README 177 KB

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  1. # SPDX-License-Identifier: GPL-2.0+
  2. #
  3. # (C) Copyright 2000 - 2013
  4. # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
  5. Summary:
  6. ========
  7. This directory contains the source code for U-Boot, a boot loader for
  8. Embedded boards based on PowerPC, ARM, MIPS and several other
  9. processors, which can be installed in a boot ROM and used to
  10. initialize and test the hardware or to download and run application
  11. code.
  12. The development of U-Boot is closely related to Linux: some parts of
  13. the source code originate in the Linux source tree, we have some
  14. header files in common, and special provision has been made to
  15. support booting of Linux images.
  16. Some attention has been paid to make this software easily
  17. configurable and extendable. For instance, all monitor commands are
  18. implemented with the same call interface, so that it's very easy to
  19. add new commands. Also, instead of permanently adding rarely used
  20. code (for instance hardware test utilities) to the monitor, you can
  21. load and run it dynamically.
  22. Status:
  23. =======
  24. In general, all boards for which a configuration option exists in the
  25. Makefile have been tested to some extent and can be considered
  26. "working". In fact, many of them are used in production systems.
  27. In case of problems see the CHANGELOG file to find out who contributed
  28. the specific port. In addition, there are various MAINTAINERS files
  29. scattered throughout the U-Boot source identifying the people or
  30. companies responsible for various boards and subsystems.
  31. Note: As of August, 2010, there is no longer a CHANGELOG file in the
  32. actual U-Boot source tree; however, it can be created dynamically
  33. from the Git log using:
  34. make CHANGELOG
  35. Where to get help:
  36. ==================
  37. In case you have questions about, problems with or contributions for
  38. U-Boot, you should send a message to the U-Boot mailing list at
  39. <u-boot@lists.denx.de>. There is also an archive of previous traffic
  40. on the mailing list - please search the archive before asking FAQ's.
  41. Please see http://lists.denx.de/pipermail/u-boot and
  42. http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
  43. Where to get source code:
  44. =========================
  45. The U-Boot source code is maintained in the Git repository at
  46. git://www.denx.de/git/u-boot.git ; you can browse it online at
  47. http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
  48. The "snapshot" links on this page allow you to download tarballs of
  49. any version you might be interested in. Official releases are also
  50. available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
  51. directory.
  52. Pre-built (and tested) images are available from
  53. ftp://ftp.denx.de/pub/u-boot/images/
  54. Where we come from:
  55. ===================
  56. - start from 8xxrom sources
  57. - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
  58. - clean up code
  59. - make it easier to add custom boards
  60. - make it possible to add other [PowerPC] CPUs
  61. - extend functions, especially:
  62. * Provide extended interface to Linux boot loader
  63. * S-Record download
  64. * network boot
  65. * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
  66. - create ARMBoot project (http://sourceforge.net/projects/armboot)
  67. - add other CPU families (starting with ARM)
  68. - create U-Boot project (http://sourceforge.net/projects/u-boot)
  69. - current project page: see http://www.denx.de/wiki/U-Boot
  70. Names and Spelling:
  71. ===================
  72. The "official" name of this project is "Das U-Boot". The spelling
  73. "U-Boot" shall be used in all written text (documentation, comments
  74. in source files etc.). Example:
  75. This is the README file for the U-Boot project.
  76. File names etc. shall be based on the string "u-boot". Examples:
  77. include/asm-ppc/u-boot.h
  78. #include <asm/u-boot.h>
  79. Variable names, preprocessor constants etc. shall be either based on
  80. the string "u_boot" or on "U_BOOT". Example:
  81. U_BOOT_VERSION u_boot_logo
  82. IH_OS_U_BOOT u_boot_hush_start
  83. Versioning:
  84. ===========
  85. Starting with the release in October 2008, the names of the releases
  86. were changed from numerical release numbers without deeper meaning
  87. into a time stamp based numbering. Regular releases are identified by
  88. names consisting of the calendar year and month of the release date.
  89. Additional fields (if present) indicate release candidates or bug fix
  90. releases in "stable" maintenance trees.
  91. Examples:
  92. U-Boot v2009.11 - Release November 2009
  93. U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
  94. U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release
  95. Directory Hierarchy:
  96. ====================
  97. /arch Architecture specific files
  98. /arc Files generic to ARC architecture
  99. /arm Files generic to ARM architecture
  100. /m68k Files generic to m68k architecture
  101. /microblaze Files generic to microblaze architecture
  102. /mips Files generic to MIPS architecture
  103. /nds32 Files generic to NDS32 architecture
  104. /nios2 Files generic to Altera NIOS2 architecture
  105. /openrisc Files generic to OpenRISC architecture
  106. /powerpc Files generic to PowerPC architecture
  107. /riscv Files generic to RISC-V architecture
  108. /sandbox Files generic to HW-independent "sandbox"
  109. /sh Files generic to SH architecture
  110. /x86 Files generic to x86 architecture
  111. /api Machine/arch independent API for external apps
  112. /board Board dependent files
  113. /cmd U-Boot commands functions
  114. /common Misc architecture independent functions
  115. /configs Board default configuration files
  116. /disk Code for disk drive partition handling
  117. /doc Documentation (don't expect too much)
  118. /drivers Commonly used device drivers
  119. /dts Contains Makefile for building internal U-Boot fdt.
  120. /examples Example code for standalone applications, etc.
  121. /fs Filesystem code (cramfs, ext2, jffs2, etc.)
  122. /include Header Files
  123. /lib Library routines generic to all architectures
  124. /Licenses Various license files
  125. /net Networking code
  126. /post Power On Self Test
  127. /scripts Various build scripts and Makefiles
  128. /test Various unit test files
  129. /tools Tools to build S-Record or U-Boot images, etc.
  130. Software Configuration:
  131. =======================
  132. Configuration is usually done using C preprocessor defines; the
  133. rationale behind that is to avoid dead code whenever possible.
  134. There are two classes of configuration variables:
  135. * Configuration _OPTIONS_:
  136. These are selectable by the user and have names beginning with
  137. "CONFIG_".
  138. * Configuration _SETTINGS_:
  139. These depend on the hardware etc. and should not be meddled with if
  140. you don't know what you're doing; they have names beginning with
  141. "CONFIG_SYS_".
  142. Previously, all configuration was done by hand, which involved creating
  143. symbolic links and editing configuration files manually. More recently,
  144. U-Boot has added the Kbuild infrastructure used by the Linux kernel,
  145. allowing you to use the "make menuconfig" command to configure your
  146. build.
  147. Selection of Processor Architecture and Board Type:
  148. ---------------------------------------------------
  149. For all supported boards there are ready-to-use default
  150. configurations available; just type "make <board_name>_defconfig".
  151. Example: For a TQM823L module type:
  152. cd u-boot
  153. make TQM823L_defconfig
  154. Note: If you're looking for the default configuration file for a board
  155. you're sure used to be there but is now missing, check the file
  156. doc/README.scrapyard for a list of no longer supported boards.
  157. Sandbox Environment:
  158. --------------------
  159. U-Boot can be built natively to run on a Linux host using the 'sandbox'
  160. board. This allows feature development which is not board- or architecture-
  161. specific to be undertaken on a native platform. The sandbox is also used to
  162. run some of U-Boot's tests.
  163. See board/sandbox/README.sandbox for more details.
  164. Board Initialisation Flow:
  165. --------------------------
  166. This is the intended start-up flow for boards. This should apply for both
  167. SPL and U-Boot proper (i.e. they both follow the same rules).
  168. Note: "SPL" stands for "Secondary Program Loader," which is explained in
  169. more detail later in this file.
  170. At present, SPL mostly uses a separate code path, but the function names
  171. and roles of each function are the same. Some boards or architectures
  172. may not conform to this. At least most ARM boards which use
  173. CONFIG_SPL_FRAMEWORK conform to this.
  174. Execution typically starts with an architecture-specific (and possibly
  175. CPU-specific) start.S file, such as:
  176. - arch/arm/cpu/armv7/start.S
  177. - arch/powerpc/cpu/mpc83xx/start.S
  178. - arch/mips/cpu/start.S
  179. and so on. From there, three functions are called; the purpose and
  180. limitations of each of these functions are described below.
  181. lowlevel_init():
  182. - purpose: essential init to permit execution to reach board_init_f()
  183. - no global_data or BSS
  184. - there is no stack (ARMv7 may have one but it will soon be removed)
  185. - must not set up SDRAM or use console
  186. - must only do the bare minimum to allow execution to continue to
  187. board_init_f()
  188. - this is almost never needed
  189. - return normally from this function
  190. board_init_f():
  191. - purpose: set up the machine ready for running board_init_r():
  192. i.e. SDRAM and serial UART
  193. - global_data is available
  194. - stack is in SRAM
  195. - BSS is not available, so you cannot use global/static variables,
  196. only stack variables and global_data
  197. Non-SPL-specific notes:
  198. - dram_init() is called to set up DRAM. If already done in SPL this
  199. can do nothing
  200. SPL-specific notes:
  201. - you can override the entire board_init_f() function with your own
  202. version as needed.
  203. - preloader_console_init() can be called here in extremis
  204. - should set up SDRAM, and anything needed to make the UART work
  205. - these is no need to clear BSS, it will be done by crt0.S
  206. - must return normally from this function (don't call board_init_r()
  207. directly)
  208. Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
  209. this point the stack and global_data are relocated to below
  210. CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
  211. memory.
  212. board_init_r():
  213. - purpose: main execution, common code
  214. - global_data is available
  215. - SDRAM is available
  216. - BSS is available, all static/global variables can be used
  217. - execution eventually continues to main_loop()
  218. Non-SPL-specific notes:
  219. - U-Boot is relocated to the top of memory and is now running from
  220. there.
  221. SPL-specific notes:
  222. - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
  223. CONFIG_SPL_STACK_R_ADDR points into SDRAM
  224. - preloader_console_init() can be called here - typically this is
  225. done by selecting CONFIG_SPL_BOARD_INIT and then supplying a
  226. spl_board_init() function containing this call
  227. - loads U-Boot or (in falcon mode) Linux
  228. Configuration Options:
  229. ----------------------
  230. Configuration depends on the combination of board and CPU type; all
  231. such information is kept in a configuration file
  232. "include/configs/<board_name>.h".
  233. Example: For a TQM823L module, all configuration settings are in
  234. "include/configs/TQM823L.h".
  235. Many of the options are named exactly as the corresponding Linux
  236. kernel configuration options. The intention is to make it easier to
  237. build a config tool - later.
  238. - ARM Platform Bus Type(CCI):
  239. CoreLink Cache Coherent Interconnect (CCI) is ARM BUS which
  240. provides full cache coherency between two clusters of multi-core
  241. CPUs and I/O coherency for devices and I/O masters
  242. CONFIG_SYS_FSL_HAS_CCI400
  243. Defined For SoC that has cache coherent interconnect
  244. CCN-400
  245. CONFIG_SYS_FSL_HAS_CCN504
  246. Defined for SoC that has cache coherent interconnect CCN-504
  247. The following options need to be configured:
  248. - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
  249. - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
  250. - 85xx CPU Options:
  251. CONFIG_SYS_PPC64
  252. Specifies that the core is a 64-bit PowerPC implementation (implements
  253. the "64" category of the Power ISA). This is necessary for ePAPR
  254. compliance, among other possible reasons.
  255. CONFIG_SYS_FSL_TBCLK_DIV
  256. Defines the core time base clock divider ratio compared to the
  257. system clock. On most PQ3 devices this is 8, on newer QorIQ
  258. devices it can be 16 or 32. The ratio varies from SoC to Soc.
  259. CONFIG_SYS_FSL_PCIE_COMPAT
  260. Defines the string to utilize when trying to match PCIe device
  261. tree nodes for the given platform.
  262. CONFIG_SYS_FSL_ERRATUM_A004510
  263. Enables a workaround for erratum A004510. If set,
  264. then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
  265. CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
  266. CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
  267. CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
  268. Defines one or two SoC revisions (low 8 bits of SVR)
  269. for which the A004510 workaround should be applied.
  270. The rest of SVR is either not relevant to the decision
  271. of whether the erratum is present (e.g. p2040 versus
  272. p2041) or is implied by the build target, which controls
  273. whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
  274. See Freescale App Note 4493 for more information about
  275. this erratum.
  276. CONFIG_A003399_NOR_WORKAROUND
  277. Enables a workaround for IFC erratum A003399. It is only
  278. required during NOR boot.
  279. CONFIG_A008044_WORKAROUND
  280. Enables a workaround for T1040/T1042 erratum A008044. It is only
  281. required during NAND boot and valid for Rev 1.0 SoC revision
  282. CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
  283. This is the value to write into CCSR offset 0x18600
  284. according to the A004510 workaround.
  285. CONFIG_SYS_FSL_DSP_DDR_ADDR
  286. This value denotes start offset of DDR memory which is
  287. connected exclusively to the DSP cores.
  288. CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
  289. This value denotes start offset of M2 memory
  290. which is directly connected to the DSP core.
  291. CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
  292. This value denotes start offset of M3 memory which is directly
  293. connected to the DSP core.
  294. CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
  295. This value denotes start offset of DSP CCSR space.
  296. CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
  297. Single Source Clock is clocking mode present in some of FSL SoC's.
  298. In this mode, a single differential clock is used to supply
  299. clocks to the sysclock, ddrclock and usbclock.
  300. CONFIG_SYS_CPC_REINIT_F
  301. This CONFIG is defined when the CPC is configured as SRAM at the
  302. time of U-Boot entry and is required to be re-initialized.
  303. CONFIG_DEEP_SLEEP
  304. Indicates this SoC supports deep sleep feature. If deep sleep is
  305. supported, core will start to execute uboot when wakes up.
  306. - Generic CPU options:
  307. CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
  308. Defines the endianess of the CPU. Implementation of those
  309. values is arch specific.
  310. CONFIG_SYS_FSL_DDR
  311. Freescale DDR driver in use. This type of DDR controller is
  312. found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
  313. SoCs.
  314. CONFIG_SYS_FSL_DDR_ADDR
  315. Freescale DDR memory-mapped register base.
  316. CONFIG_SYS_FSL_DDR_EMU
  317. Specify emulator support for DDR. Some DDR features such as
  318. deskew training are not available.
  319. CONFIG_SYS_FSL_DDRC_GEN1
  320. Freescale DDR1 controller.
  321. CONFIG_SYS_FSL_DDRC_GEN2
  322. Freescale DDR2 controller.
  323. CONFIG_SYS_FSL_DDRC_GEN3
  324. Freescale DDR3 controller.
  325. CONFIG_SYS_FSL_DDRC_GEN4
  326. Freescale DDR4 controller.
  327. CONFIG_SYS_FSL_DDRC_ARM_GEN3
  328. Freescale DDR3 controller for ARM-based SoCs.
  329. CONFIG_SYS_FSL_DDR1
  330. Board config to use DDR1. It can be enabled for SoCs with
  331. Freescale DDR1 or DDR2 controllers, depending on the board
  332. implemetation.
  333. CONFIG_SYS_FSL_DDR2
  334. Board config to use DDR2. It can be enabled for SoCs with
  335. Freescale DDR2 or DDR3 controllers, depending on the board
  336. implementation.
  337. CONFIG_SYS_FSL_DDR3
  338. Board config to use DDR3. It can be enabled for SoCs with
  339. Freescale DDR3 or DDR3L controllers.
  340. CONFIG_SYS_FSL_DDR3L
  341. Board config to use DDR3L. It can be enabled for SoCs with
  342. DDR3L controllers.
  343. CONFIG_SYS_FSL_DDR4
  344. Board config to use DDR4. It can be enabled for SoCs with
  345. DDR4 controllers.
  346. CONFIG_SYS_FSL_IFC_BE
  347. Defines the IFC controller register space as Big Endian
  348. CONFIG_SYS_FSL_IFC_LE
  349. Defines the IFC controller register space as Little Endian
  350. CONFIG_SYS_FSL_IFC_CLK_DIV
  351. Defines divider of platform clock(clock input to IFC controller).
  352. CONFIG_SYS_FSL_LBC_CLK_DIV
  353. Defines divider of platform clock(clock input to eLBC controller).
  354. CONFIG_SYS_FSL_PBL_PBI
  355. It enables addition of RCW (Power on reset configuration) in built image.
  356. Please refer doc/README.pblimage for more details
  357. CONFIG_SYS_FSL_PBL_RCW
  358. It adds PBI(pre-boot instructions) commands in u-boot build image.
  359. PBI commands can be used to configure SoC before it starts the execution.
  360. Please refer doc/README.pblimage for more details
  361. CONFIG_SPL_FSL_PBL
  362. It adds a target to create boot binary having SPL binary in PBI format
  363. concatenated with u-boot binary.
  364. CONFIG_SYS_FSL_DDR_BE
  365. Defines the DDR controller register space as Big Endian
  366. CONFIG_SYS_FSL_DDR_LE
  367. Defines the DDR controller register space as Little Endian
  368. CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
  369. Physical address from the view of DDR controllers. It is the
  370. same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
  371. it could be different for ARM SoCs.
  372. CONFIG_SYS_FSL_DDR_INTLV_256B
  373. DDR controller interleaving on 256-byte. This is a special
  374. interleaving mode, handled by Dickens for Freescale layerscape
  375. SoCs with ARM core.
  376. CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
  377. Number of controllers used as main memory.
  378. CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
  379. Number of controllers used for other than main memory.
  380. CONFIG_SYS_FSL_HAS_DP_DDR
  381. Defines the SoC has DP-DDR used for DPAA.
  382. CONFIG_SYS_FSL_SEC_BE
  383. Defines the SEC controller register space as Big Endian
  384. CONFIG_SYS_FSL_SEC_LE
  385. Defines the SEC controller register space as Little Endian
  386. - MIPS CPU options:
  387. CONFIG_SYS_INIT_SP_OFFSET
  388. Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
  389. pointer. This is needed for the temporary stack before
  390. relocation.
  391. CONFIG_XWAY_SWAP_BYTES
  392. Enable compilation of tools/xway-swap-bytes needed for Lantiq
  393. XWAY SoCs for booting from NOR flash. The U-Boot image needs to
  394. be swapped if a flash programmer is used.
  395. - ARM options:
  396. CONFIG_SYS_EXCEPTION_VECTORS_HIGH
  397. Select high exception vectors of the ARM core, e.g., do not
  398. clear the V bit of the c1 register of CP15.
  399. COUNTER_FREQUENCY
  400. Generic timer clock source frequency.
  401. COUNTER_FREQUENCY_REAL
  402. Generic timer clock source frequency if the real clock is
  403. different from COUNTER_FREQUENCY, and can only be determined
  404. at run time.
  405. - Tegra SoC options:
  406. CONFIG_TEGRA_SUPPORT_NON_SECURE
  407. Support executing U-Boot in non-secure (NS) mode. Certain
  408. impossible actions will be skipped if the CPU is in NS mode,
  409. such as ARM architectural timer initialization.
  410. - Linux Kernel Interface:
  411. CONFIG_CLOCKS_IN_MHZ
  412. U-Boot stores all clock information in Hz
  413. internally. For binary compatibility with older Linux
  414. kernels (which expect the clocks passed in the
  415. bd_info data to be in MHz) the environment variable
  416. "clocks_in_mhz" can be defined so that U-Boot
  417. converts clock data to MHZ before passing it to the
  418. Linux kernel.
  419. When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
  420. "clocks_in_mhz=1" is automatically included in the
  421. default environment.
  422. CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
  423. When transferring memsize parameter to Linux, some versions
  424. expect it to be in bytes, others in MB.
  425. Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
  426. CONFIG_OF_LIBFDT
  427. New kernel versions are expecting firmware settings to be
  428. passed using flattened device trees (based on open firmware
  429. concepts).
  430. CONFIG_OF_LIBFDT
  431. * New libfdt-based support
  432. * Adds the "fdt" command
  433. * The bootm command automatically updates the fdt
  434. OF_TBCLK - The timebase frequency.
  435. OF_STDOUT_PATH - The path to the console device
  436. boards with QUICC Engines require OF_QE to set UCC MAC
  437. addresses
  438. CONFIG_OF_BOARD_SETUP
  439. Board code has addition modification that it wants to make
  440. to the flat device tree before handing it off to the kernel
  441. CONFIG_OF_SYSTEM_SETUP
  442. Other code has addition modification that it wants to make
  443. to the flat device tree before handing it off to the kernel.
  444. This causes ft_system_setup() to be called before booting
  445. the kernel.
  446. CONFIG_OF_IDE_FIXUP
  447. U-Boot can detect if an IDE device is present or not.
  448. If not, and this new config option is activated, U-Boot
  449. removes the ATA node from the DTS before booting Linux,
  450. so the Linux IDE driver does not probe the device and
  451. crash. This is needed for buggy hardware (uc101) where
  452. no pull down resistor is connected to the signal IDE5V_DD7.
  453. CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
  454. This setting is mandatory for all boards that have only one
  455. machine type and must be used to specify the machine type
  456. number as it appears in the ARM machine registry
  457. (see http://www.arm.linux.org.uk/developer/machines/).
  458. Only boards that have multiple machine types supported
  459. in a single configuration file and the machine type is
  460. runtime discoverable, do not have to use this setting.
  461. - vxWorks boot parameters:
  462. bootvx constructs a valid bootline using the following
  463. environments variables: bootdev, bootfile, ipaddr, netmask,
  464. serverip, gatewayip, hostname, othbootargs.
  465. It loads the vxWorks image pointed bootfile.
  466. Note: If a "bootargs" environment is defined, it will overwride
  467. the defaults discussed just above.
  468. - Cache Configuration:
  469. CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
  470. CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
  471. CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
  472. - Cache Configuration for ARM:
  473. CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
  474. controller
  475. CONFIG_SYS_PL310_BASE - Physical base address of PL310
  476. controller register space
  477. - Serial Ports:
  478. CONFIG_PL010_SERIAL
  479. Define this if you want support for Amba PrimeCell PL010 UARTs.
  480. CONFIG_PL011_SERIAL
  481. Define this if you want support for Amba PrimeCell PL011 UARTs.
  482. CONFIG_PL011_CLOCK
  483. If you have Amba PrimeCell PL011 UARTs, set this variable to
  484. the clock speed of the UARTs.
  485. CONFIG_PL01x_PORTS
  486. If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
  487. define this to a list of base addresses for each (supported)
  488. port. See e.g. include/configs/versatile.h
  489. CONFIG_SERIAL_HW_FLOW_CONTROL
  490. Define this variable to enable hw flow control in serial driver.
  491. Current user of this option is drivers/serial/nsl16550.c driver
  492. - Console Baudrate:
  493. CONFIG_BAUDRATE - in bps
  494. Select one of the baudrates listed in
  495. CONFIG_SYS_BAUDRATE_TABLE, see below.
  496. - Autoboot Command:
  497. CONFIG_BOOTCOMMAND
  498. Only needed when CONFIG_BOOTDELAY is enabled;
  499. define a command string that is automatically executed
  500. when no character is read on the console interface
  501. within "Boot Delay" after reset.
  502. CONFIG_RAMBOOT and CONFIG_NFSBOOT
  503. The value of these goes into the environment as
  504. "ramboot" and "nfsboot" respectively, and can be used
  505. as a convenience, when switching between booting from
  506. RAM and NFS.
  507. - Pre-Boot Commands:
  508. CONFIG_PREBOOT
  509. When this option is #defined, the existence of the
  510. environment variable "preboot" will be checked
  511. immediately before starting the CONFIG_BOOTDELAY
  512. countdown and/or running the auto-boot command resp.
  513. entering interactive mode.
  514. This feature is especially useful when "preboot" is
  515. automatically generated or modified. For an example
  516. see the LWMON board specific code: here "preboot" is
  517. modified when the user holds down a certain
  518. combination of keys on the (special) keyboard when
  519. booting the systems
  520. - Serial Download Echo Mode:
  521. CONFIG_LOADS_ECHO
  522. If defined to 1, all characters received during a
  523. serial download (using the "loads" command) are
  524. echoed back. This might be needed by some terminal
  525. emulations (like "cu"), but may as well just take
  526. time on others. This setting #define's the initial
  527. value of the "loads_echo" environment variable.
  528. - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
  529. CONFIG_KGDB_BAUDRATE
  530. Select one of the baudrates listed in
  531. CONFIG_SYS_BAUDRATE_TABLE, see below.
  532. - Removal of commands
  533. If no commands are needed to boot, you can disable
  534. CONFIG_CMDLINE to remove them. In this case, the command line
  535. will not be available, and when U-Boot wants to execute the
  536. boot command (on start-up) it will call board_run_command()
  537. instead. This can reduce image size significantly for very
  538. simple boot procedures.
  539. - Regular expression support:
  540. CONFIG_REGEX
  541. If this variable is defined, U-Boot is linked against
  542. the SLRE (Super Light Regular Expression) library,
  543. which adds regex support to some commands, as for
  544. example "env grep" and "setexpr".
  545. - Device tree:
  546. CONFIG_OF_CONTROL
  547. If this variable is defined, U-Boot will use a device tree
  548. to configure its devices, instead of relying on statically
  549. compiled #defines in the board file. This option is
  550. experimental and only available on a few boards. The device
  551. tree is available in the global data as gd->fdt_blob.
  552. U-Boot needs to get its device tree from somewhere. This can
  553. be done using one of the three options below:
  554. CONFIG_OF_EMBED
  555. If this variable is defined, U-Boot will embed a device tree
  556. binary in its image. This device tree file should be in the
  557. board directory and called <soc>-<board>.dts. The binary file
  558. is then picked up in board_init_f() and made available through
  559. the global data structure as gd->fdt_blob.
  560. CONFIG_OF_SEPARATE
  561. If this variable is defined, U-Boot will build a device tree
  562. binary. It will be called u-boot.dtb. Architecture-specific
  563. code will locate it at run-time. Generally this works by:
  564. cat u-boot.bin u-boot.dtb >image.bin
  565. and in fact, U-Boot does this for you, creating a file called
  566. u-boot-dtb.bin which is useful in the common case. You can
  567. still use the individual files if you need something more
  568. exotic.
  569. CONFIG_OF_BOARD
  570. If this variable is defined, U-Boot will use the device tree
  571. provided by the board at runtime instead of embedding one with
  572. the image. Only boards defining board_fdt_blob_setup() support
  573. this option (see include/fdtdec.h file).
  574. - Watchdog:
  575. CONFIG_WATCHDOG
  576. If this variable is defined, it enables watchdog
  577. support for the SoC. There must be support in the SoC
  578. specific code for a watchdog. For the 8xx
  579. CPUs, the SIU Watchdog feature is enabled in the SYPCR
  580. register. When supported for a specific SoC is
  581. available, then no further board specific code should
  582. be needed to use it.
  583. CONFIG_HW_WATCHDOG
  584. When using a watchdog circuitry external to the used
  585. SoC, then define this variable and provide board
  586. specific code for the "hw_watchdog_reset" function.
  587. CONFIG_AT91_HW_WDT_TIMEOUT
  588. specify the timeout in seconds. default 2 seconds.
  589. - Real-Time Clock:
  590. When CONFIG_CMD_DATE is selected, the type of the RTC
  591. has to be selected, too. Define exactly one of the
  592. following options:
  593. CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
  594. CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
  595. CONFIG_RTC_MC146818 - use MC146818 RTC
  596. CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
  597. CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
  598. CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
  599. CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
  600. CONFIG_RTC_DS164x - use Dallas DS164x RTC
  601. CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
  602. CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
  603. CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
  604. CONFIG_SYS_RV3029_TCR - enable trickle charger on
  605. RV3029 RTC.
  606. Note that if the RTC uses I2C, then the I2C interface
  607. must also be configured. See I2C Support, below.
  608. - GPIO Support:
  609. CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
  610. The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
  611. chip-ngpio pairs that tell the PCA953X driver the number of
  612. pins supported by a particular chip.
  613. Note that if the GPIO device uses I2C, then the I2C interface
  614. must also be configured. See I2C Support, below.
  615. - I/O tracing:
  616. When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
  617. accesses and can checksum them or write a list of them out
  618. to memory. See the 'iotrace' command for details. This is
  619. useful for testing device drivers since it can confirm that
  620. the driver behaves the same way before and after a code
  621. change. Currently this is supported on sandbox and arm. To
  622. add support for your architecture, add '#include <iotrace.h>'
  623. to the bottom of arch/<arch>/include/asm/io.h and test.
  624. Example output from the 'iotrace stats' command is below.
  625. Note that if the trace buffer is exhausted, the checksum will
  626. still continue to operate.
  627. iotrace is enabled
  628. Start: 10000000 (buffer start address)
  629. Size: 00010000 (buffer size)
  630. Offset: 00000120 (current buffer offset)
  631. Output: 10000120 (start + offset)
  632. Count: 00000018 (number of trace records)
  633. CRC32: 9526fb66 (CRC32 of all trace records)
  634. - Timestamp Support:
  635. When CONFIG_TIMESTAMP is selected, the timestamp
  636. (date and time) of an image is printed by image
  637. commands like bootm or iminfo. This option is
  638. automatically enabled when you select CONFIG_CMD_DATE .
  639. - Partition Labels (disklabels) Supported:
  640. Zero or more of the following:
  641. CONFIG_MAC_PARTITION Apple's MacOS partition table.
  642. CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
  643. CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
  644. bootloader. Note 2TB partition limit; see
  645. disk/part_efi.c
  646. CONFIG_SCSI) you must configure support for at
  647. least one non-MTD partition type as well.
  648. - IDE Reset method:
  649. CONFIG_IDE_RESET_ROUTINE - this is defined in several
  650. board configurations files but used nowhere!
  651. CONFIG_IDE_RESET - is this is defined, IDE Reset will
  652. be performed by calling the function
  653. ide_set_reset(int reset)
  654. which has to be defined in a board specific file
  655. - ATAPI Support:
  656. CONFIG_ATAPI
  657. Set this to enable ATAPI support.
  658. - LBA48 Support
  659. CONFIG_LBA48
  660. Set this to enable support for disks larger than 137GB
  661. Also look at CONFIG_SYS_64BIT_LBA.
  662. Whithout these , LBA48 support uses 32bit variables and will 'only'
  663. support disks up to 2.1TB.
  664. CONFIG_SYS_64BIT_LBA:
  665. When enabled, makes the IDE subsystem use 64bit sector addresses.
  666. Default is 32bit.
  667. - SCSI Support:
  668. CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
  669. CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
  670. CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
  671. maximum numbers of LUNs, SCSI ID's and target
  672. devices.
  673. The environment variable 'scsidevs' is set to the number of
  674. SCSI devices found during the last scan.
  675. - NETWORK Support (PCI):
  676. CONFIG_E1000
  677. Support for Intel 8254x/8257x gigabit chips.
  678. CONFIG_E1000_SPI
  679. Utility code for direct access to the SPI bus on Intel 8257x.
  680. This does not do anything useful unless you set at least one
  681. of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
  682. CONFIG_E1000_SPI_GENERIC
  683. Allow generic access to the SPI bus on the Intel 8257x, for
  684. example with the "sspi" command.
  685. CONFIG_EEPRO100
  686. Support for Intel 82557/82559/82559ER chips.
  687. Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
  688. write routine for first time initialisation.
  689. CONFIG_TULIP
  690. Support for Digital 2114x chips.
  691. Optional CONFIG_TULIP_SELECT_MEDIA for board specific
  692. modem chip initialisation (KS8761/QS6611).
  693. CONFIG_NATSEMI
  694. Support for National dp83815 chips.
  695. CONFIG_NS8382X
  696. Support for National dp8382[01] gigabit chips.
  697. - NETWORK Support (other):
  698. CONFIG_DRIVER_AT91EMAC
  699. Support for AT91RM9200 EMAC.
  700. CONFIG_RMII
  701. Define this to use reduced MII inteface
  702. CONFIG_DRIVER_AT91EMAC_QUIET
  703. If this defined, the driver is quiet.
  704. The driver doen't show link status messages.
  705. CONFIG_CALXEDA_XGMAC
  706. Support for the Calxeda XGMAC device
  707. CONFIG_LAN91C96
  708. Support for SMSC's LAN91C96 chips.
  709. CONFIG_LAN91C96_USE_32_BIT
  710. Define this to enable 32 bit addressing
  711. CONFIG_SMC91111
  712. Support for SMSC's LAN91C111 chip
  713. CONFIG_SMC91111_BASE
  714. Define this to hold the physical address
  715. of the device (I/O space)
  716. CONFIG_SMC_USE_32_BIT
  717. Define this if data bus is 32 bits
  718. CONFIG_SMC_USE_IOFUNCS
  719. Define this to use i/o functions instead of macros
  720. (some hardware wont work with macros)
  721. CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
  722. Define this if you have more then 3 PHYs.
  723. CONFIG_FTGMAC100
  724. Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
  725. CONFIG_FTGMAC100_EGIGA
  726. Define this to use GE link update with gigabit PHY.
  727. Define this if FTGMAC100 is connected to gigabit PHY.
  728. If your system has 10/100 PHY only, it might not occur
  729. wrong behavior. Because PHY usually return timeout or
  730. useless data when polling gigabit status and gigabit
  731. control registers. This behavior won't affect the
  732. correctnessof 10/100 link speed update.
  733. CONFIG_SH_ETHER
  734. Support for Renesas on-chip Ethernet controller
  735. CONFIG_SH_ETHER_USE_PORT
  736. Define the number of ports to be used
  737. CONFIG_SH_ETHER_PHY_ADDR
  738. Define the ETH PHY's address
  739. CONFIG_SH_ETHER_CACHE_WRITEBACK
  740. If this option is set, the driver enables cache flush.
  741. - PWM Support:
  742. CONFIG_PWM_IMX
  743. Support for PWM module on the imx6.
  744. - TPM Support:
  745. CONFIG_TPM
  746. Support TPM devices.
  747. CONFIG_TPM_TIS_INFINEON
  748. Support for Infineon i2c bus TPM devices. Only one device
  749. per system is supported at this time.
  750. CONFIG_TPM_TIS_I2C_BURST_LIMITATION
  751. Define the burst count bytes upper limit
  752. CONFIG_TPM_ST33ZP24
  753. Support for STMicroelectronics TPM devices. Requires DM_TPM support.
  754. CONFIG_TPM_ST33ZP24_I2C
  755. Support for STMicroelectronics ST33ZP24 I2C devices.
  756. Requires TPM_ST33ZP24 and I2C.
  757. CONFIG_TPM_ST33ZP24_SPI
  758. Support for STMicroelectronics ST33ZP24 SPI devices.
  759. Requires TPM_ST33ZP24 and SPI.
  760. CONFIG_TPM_ATMEL_TWI
  761. Support for Atmel TWI TPM device. Requires I2C support.
  762. CONFIG_TPM_TIS_LPC
  763. Support for generic parallel port TPM devices. Only one device
  764. per system is supported at this time.
  765. CONFIG_TPM_TIS_BASE_ADDRESS
  766. Base address where the generic TPM device is mapped
  767. to. Contemporary x86 systems usually map it at
  768. 0xfed40000.
  769. CONFIG_TPM
  770. Define this to enable the TPM support library which provides
  771. functional interfaces to some TPM commands.
  772. Requires support for a TPM device.
  773. CONFIG_TPM_AUTH_SESSIONS
  774. Define this to enable authorized functions in the TPM library.
  775. Requires CONFIG_TPM and CONFIG_SHA1.
  776. - USB Support:
  777. At the moment only the UHCI host controller is
  778. supported (PIP405, MIP405); define
  779. CONFIG_USB_UHCI to enable it.
  780. define CONFIG_USB_KEYBOARD to enable the USB Keyboard
  781. and define CONFIG_USB_STORAGE to enable the USB
  782. storage devices.
  783. Note:
  784. Supported are USB Keyboards and USB Floppy drives
  785. (TEAC FD-05PUB).
  786. CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
  787. txfilltuning field in the EHCI controller on reset.
  788. CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
  789. HW module registers.
  790. - USB Device:
  791. Define the below if you wish to use the USB console.
  792. Once firmware is rebuilt from a serial console issue the
  793. command "setenv stdin usbtty; setenv stdout usbtty" and
  794. attach your USB cable. The Unix command "dmesg" should print
  795. it has found a new device. The environment variable usbtty
  796. can be set to gserial or cdc_acm to enable your device to
  797. appear to a USB host as a Linux gserial device or a
  798. Common Device Class Abstract Control Model serial device.
  799. If you select usbtty = gserial you should be able to enumerate
  800. a Linux host by
  801. # modprobe usbserial vendor=0xVendorID product=0xProductID
  802. else if using cdc_acm, simply setting the environment
  803. variable usbtty to be cdc_acm should suffice. The following
  804. might be defined in YourBoardName.h
  805. CONFIG_USB_DEVICE
  806. Define this to build a UDC device
  807. CONFIG_USB_TTY
  808. Define this to have a tty type of device available to
  809. talk to the UDC device
  810. CONFIG_USBD_HS
  811. Define this to enable the high speed support for usb
  812. device and usbtty. If this feature is enabled, a routine
  813. int is_usbd_high_speed(void)
  814. also needs to be defined by the driver to dynamically poll
  815. whether the enumeration has succeded at high speed or full
  816. speed.
  817. CONFIG_SYS_CONSOLE_IS_IN_ENV
  818. Define this if you want stdin, stdout &/or stderr to
  819. be set to usbtty.
  820. If you have a USB-IF assigned VendorID then you may wish to
  821. define your own vendor specific values either in BoardName.h
  822. or directly in usbd_vendor_info.h. If you don't define
  823. CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
  824. CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
  825. should pretend to be a Linux device to it's target host.
  826. CONFIG_USBD_MANUFACTURER
  827. Define this string as the name of your company for
  828. - CONFIG_USBD_MANUFACTURER "my company"
  829. CONFIG_USBD_PRODUCT_NAME
  830. Define this string as the name of your product
  831. - CONFIG_USBD_PRODUCT_NAME "acme usb device"
  832. CONFIG_USBD_VENDORID
  833. Define this as your assigned Vendor ID from the USB
  834. Implementors Forum. This *must* be a genuine Vendor ID
  835. to avoid polluting the USB namespace.
  836. - CONFIG_USBD_VENDORID 0xFFFF
  837. CONFIG_USBD_PRODUCTID
  838. Define this as the unique Product ID
  839. for your device
  840. - CONFIG_USBD_PRODUCTID 0xFFFF
  841. - ULPI Layer Support:
  842. The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
  843. the generic ULPI layer. The generic layer accesses the ULPI PHY
  844. via the platform viewport, so you need both the genric layer and
  845. the viewport enabled. Currently only Chipidea/ARC based
  846. viewport is supported.
  847. To enable the ULPI layer support, define CONFIG_USB_ULPI and
  848. CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
  849. If your ULPI phy needs a different reference clock than the
  850. standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
  851. the appropriate value in Hz.
  852. - MMC Support:
  853. The MMC controller on the Intel PXA is supported. To
  854. enable this define CONFIG_MMC. The MMC can be
  855. accessed from the boot prompt by mapping the device
  856. to physical memory similar to flash. Command line is
  857. enabled with CONFIG_CMD_MMC. The MMC driver also works with
  858. the FAT fs. This is enabled with CONFIG_CMD_FAT.
  859. CONFIG_SH_MMCIF
  860. Support for Renesas on-chip MMCIF controller
  861. CONFIG_SH_MMCIF_ADDR
  862. Define the base address of MMCIF registers
  863. CONFIG_SH_MMCIF_CLK
  864. Define the clock frequency for MMCIF
  865. CONFIG_SUPPORT_EMMC_BOOT
  866. Enable some additional features of the eMMC boot partitions.
  867. - USB Device Firmware Update (DFU) class support:
  868. CONFIG_DFU_OVER_USB
  869. This enables the USB portion of the DFU USB class
  870. CONFIG_DFU_MMC
  871. This enables support for exposing (e)MMC devices via DFU.
  872. CONFIG_DFU_NAND
  873. This enables support for exposing NAND devices via DFU.
  874. CONFIG_DFU_RAM
  875. This enables support for exposing RAM via DFU.
  876. Note: DFU spec refer to non-volatile memory usage, but
  877. allow usages beyond the scope of spec - here RAM usage,
  878. one that would help mostly the developer.
  879. CONFIG_SYS_DFU_DATA_BUF_SIZE
  880. Dfu transfer uses a buffer before writing data to the
  881. raw storage device. Make the size (in bytes) of this buffer
  882. configurable. The size of this buffer is also configurable
  883. through the "dfu_bufsiz" environment variable.
  884. CONFIG_SYS_DFU_MAX_FILE_SIZE
  885. When updating files rather than the raw storage device,
  886. we use a static buffer to copy the file into and then write
  887. the buffer once we've been given the whole file. Define
  888. this to the maximum filesize (in bytes) for the buffer.
  889. Default is 4 MiB if undefined.
  890. DFU_DEFAULT_POLL_TIMEOUT
  891. Poll timeout [ms], is the timeout a device can send to the
  892. host. The host must wait for this timeout before sending
  893. a subsequent DFU_GET_STATUS request to the device.
  894. DFU_MANIFEST_POLL_TIMEOUT
  895. Poll timeout [ms], which the device sends to the host when
  896. entering dfuMANIFEST state. Host waits this timeout, before
  897. sending again an USB request to the device.
  898. - Journaling Flash filesystem support:
  899. CONFIG_JFFS2_NAND
  900. Define these for a default partition on a NAND device
  901. CONFIG_SYS_JFFS2_FIRST_SECTOR,
  902. CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
  903. Define these for a default partition on a NOR device
  904. - Keyboard Support:
  905. See Kconfig help for available keyboard drivers.
  906. CONFIG_KEYBOARD
  907. Define this to enable a custom keyboard support.
  908. This simply calls drv_keyboard_init() which must be
  909. defined in your board-specific files. This option is deprecated
  910. and is only used by novena. For new boards, use driver model
  911. instead.
  912. - Video support:
  913. CONFIG_FSL_DIU_FB
  914. Enable the Freescale DIU video driver. Reference boards for
  915. SOCs that have a DIU should define this macro to enable DIU
  916. support, and should also define these other macros:
  917. CONFIG_SYS_DIU_ADDR
  918. CONFIG_VIDEO
  919. CONFIG_CFB_CONSOLE
  920. CONFIG_VIDEO_SW_CURSOR
  921. CONFIG_VGA_AS_SINGLE_DEVICE
  922. CONFIG_VIDEO_LOGO
  923. CONFIG_VIDEO_BMP_LOGO
  924. The DIU driver will look for the 'video-mode' environment
  925. variable, and if defined, enable the DIU as a console during
  926. boot. See the documentation file doc/README.video for a
  927. description of this variable.
  928. - LCD Support: CONFIG_LCD
  929. Define this to enable LCD support (for output to LCD
  930. display); also select one of the supported displays
  931. by defining one of these:
  932. CONFIG_ATMEL_LCD:
  933. HITACHI TX09D70VM1CCA, 3.5", 240x320.
  934. CONFIG_NEC_NL6448AC33:
  935. NEC NL6448AC33-18. Active, color, single scan.
  936. CONFIG_NEC_NL6448BC20
  937. NEC NL6448BC20-08. 6.5", 640x480.
  938. Active, color, single scan.
  939. CONFIG_NEC_NL6448BC33_54
  940. NEC NL6448BC33-54. 10.4", 640x480.
  941. Active, color, single scan.
  942. CONFIG_SHARP_16x9
  943. Sharp 320x240. Active, color, single scan.
  944. It isn't 16x9, and I am not sure what it is.
  945. CONFIG_SHARP_LQ64D341
  946. Sharp LQ64D341 display, 640x480.
  947. Active, color, single scan.
  948. CONFIG_HLD1045
  949. HLD1045 display, 640x480.
  950. Active, color, single scan.
  951. CONFIG_OPTREX_BW
  952. Optrex CBL50840-2 NF-FW 99 22 M5
  953. or
  954. Hitachi LMG6912RPFC-00T
  955. or
  956. Hitachi SP14Q002
  957. 320x240. Black & white.
  958. CONFIG_LCD_ALIGNMENT
  959. Normally the LCD is page-aligned (typically 4KB). If this is
  960. defined then the LCD will be aligned to this value instead.
  961. For ARM it is sometimes useful to use MMU_SECTION_SIZE
  962. here, since it is cheaper to change data cache settings on
  963. a per-section basis.
  964. CONFIG_LCD_ROTATION
  965. Sometimes, for example if the display is mounted in portrait
  966. mode or even if it's mounted landscape but rotated by 180degree,
  967. we need to rotate our content of the display relative to the
  968. framebuffer, so that user can read the messages which are
  969. printed out.
  970. Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
  971. initialized with a given rotation from "vl_rot" out of
  972. "vidinfo_t" which is provided by the board specific code.
  973. The value for vl_rot is coded as following (matching to
  974. fbcon=rotate:<n> linux-kernel commandline):
  975. 0 = no rotation respectively 0 degree
  976. 1 = 90 degree rotation
  977. 2 = 180 degree rotation
  978. 3 = 270 degree rotation
  979. If CONFIG_LCD_ROTATION is not defined, the console will be
  980. initialized with 0degree rotation.
  981. CONFIG_LCD_BMP_RLE8
  982. Support drawing of RLE8-compressed bitmaps on the LCD.
  983. CONFIG_I2C_EDID
  984. Enables an 'i2c edid' command which can read EDID
  985. information over I2C from an attached LCD display.
  986. - Splash Screen Support: CONFIG_SPLASH_SCREEN
  987. If this option is set, the environment is checked for
  988. a variable "splashimage". If found, the usual display
  989. of logo, copyright and system information on the LCD
  990. is suppressed and the BMP image at the address
  991. specified in "splashimage" is loaded instead. The
  992. console is redirected to the "nulldev", too. This
  993. allows for a "silent" boot where a splash screen is
  994. loaded very quickly after power-on.
  995. CONFIG_SPLASHIMAGE_GUARD
  996. If this option is set, then U-Boot will prevent the environment
  997. variable "splashimage" from being set to a problematic address
  998. (see doc/README.displaying-bmps).
  999. This option is useful for targets where, due to alignment
  1000. restrictions, an improperly aligned BMP image will cause a data
  1001. abort. If you think you will not have problems with unaligned
  1002. accesses (for example because your toolchain prevents them)
  1003. there is no need to set this option.
  1004. CONFIG_SPLASH_SCREEN_ALIGN
  1005. If this option is set the splash image can be freely positioned
  1006. on the screen. Environment variable "splashpos" specifies the
  1007. position as "x,y". If a positive number is given it is used as
  1008. number of pixel from left/top. If a negative number is given it
  1009. is used as number of pixel from right/bottom. You can also
  1010. specify 'm' for centering the image.
  1011. Example:
  1012. setenv splashpos m,m
  1013. => image at center of screen
  1014. setenv splashpos 30,20
  1015. => image at x = 30 and y = 20
  1016. setenv splashpos -10,m
  1017. => vertically centered image
  1018. at x = dspWidth - bmpWidth - 9
  1019. - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
  1020. If this option is set, additionally to standard BMP
  1021. images, gzipped BMP images can be displayed via the
  1022. splashscreen support or the bmp command.
  1023. - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
  1024. If this option is set, 8-bit RLE compressed BMP images
  1025. can be displayed via the splashscreen support or the
  1026. bmp command.
  1027. - Compression support:
  1028. CONFIG_GZIP
  1029. Enabled by default to support gzip compressed images.
  1030. CONFIG_BZIP2
  1031. If this option is set, support for bzip2 compressed
  1032. images is included. If not, only uncompressed and gzip
  1033. compressed images are supported.
  1034. NOTE: the bzip2 algorithm requires a lot of RAM, so
  1035. the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
  1036. be at least 4MB.
  1037. - MII/PHY support:
  1038. CONFIG_PHY_CLOCK_FREQ (ppc4xx)
  1039. The clock frequency of the MII bus
  1040. CONFIG_PHY_RESET_DELAY
  1041. Some PHY like Intel LXT971A need extra delay after
  1042. reset before any MII register access is possible.
  1043. For such PHY, set this option to the usec delay
  1044. required. (minimum 300usec for LXT971A)
  1045. CONFIG_PHY_CMD_DELAY (ppc4xx)
  1046. Some PHY like Intel LXT971A need extra delay after
  1047. command issued before MII status register can be read
  1048. - IP address:
  1049. CONFIG_IPADDR
  1050. Define a default value for the IP address to use for
  1051. the default Ethernet interface, in case this is not
  1052. determined through e.g. bootp.
  1053. (Environment variable "ipaddr")
  1054. - Server IP address:
  1055. CONFIG_SERVERIP
  1056. Defines a default value for the IP address of a TFTP
  1057. server to contact when using the "tftboot" command.
  1058. (Environment variable "serverip")
  1059. CONFIG_KEEP_SERVERADDR
  1060. Keeps the server's MAC address, in the env 'serveraddr'
  1061. for passing to bootargs (like Linux's netconsole option)
  1062. - Gateway IP address:
  1063. CONFIG_GATEWAYIP
  1064. Defines a default value for the IP address of the
  1065. default router where packets to other networks are
  1066. sent to.
  1067. (Environment variable "gatewayip")
  1068. - Subnet mask:
  1069. CONFIG_NETMASK
  1070. Defines a default value for the subnet mask (or
  1071. routing prefix) which is used to determine if an IP
  1072. address belongs to the local subnet or needs to be
  1073. forwarded through a router.
  1074. (Environment variable "netmask")
  1075. - Multicast TFTP Mode:
  1076. CONFIG_MCAST_TFTP
  1077. Defines whether you want to support multicast TFTP as per
  1078. rfc-2090; for example to work with atftp. Lets lots of targets
  1079. tftp down the same boot image concurrently. Note: the Ethernet
  1080. driver in use must provide a function: mcast() to join/leave a
  1081. multicast group.
  1082. - BOOTP Recovery Mode:
  1083. CONFIG_BOOTP_RANDOM_DELAY
  1084. If you have many targets in a network that try to
  1085. boot using BOOTP, you may want to avoid that all
  1086. systems send out BOOTP requests at precisely the same
  1087. moment (which would happen for instance at recovery
  1088. from a power failure, when all systems will try to
  1089. boot, thus flooding the BOOTP server. Defining
  1090. CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
  1091. inserted before sending out BOOTP requests. The
  1092. following delays are inserted then:
  1093. 1st BOOTP request: delay 0 ... 1 sec
  1094. 2nd BOOTP request: delay 0 ... 2 sec
  1095. 3rd BOOTP request: delay 0 ... 4 sec
  1096. 4th and following
  1097. BOOTP requests: delay 0 ... 8 sec
  1098. CONFIG_BOOTP_ID_CACHE_SIZE
  1099. BOOTP packets are uniquely identified using a 32-bit ID. The
  1100. server will copy the ID from client requests to responses and
  1101. U-Boot will use this to determine if it is the destination of
  1102. an incoming response. Some servers will check that addresses
  1103. aren't in use before handing them out (usually using an ARP
  1104. ping) and therefore take up to a few hundred milliseconds to
  1105. respond. Network congestion may also influence the time it
  1106. takes for a response to make it back to the client. If that
  1107. time is too long, U-Boot will retransmit requests. In order
  1108. to allow earlier responses to still be accepted after these
  1109. retransmissions, U-Boot's BOOTP client keeps a small cache of
  1110. IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
  1111. cache. The default is to keep IDs for up to four outstanding
  1112. requests. Increasing this will allow U-Boot to accept offers
  1113. from a BOOTP client in networks with unusually high latency.
  1114. - DHCP Advanced Options:
  1115. You can fine tune the DHCP functionality by defining
  1116. CONFIG_BOOTP_* symbols:
  1117. CONFIG_BOOTP_NISDOMAIN
  1118. CONFIG_BOOTP_BOOTFILESIZE
  1119. CONFIG_BOOTP_SEND_HOSTNAME
  1120. CONFIG_BOOTP_NTPSERVER
  1121. CONFIG_BOOTP_TIMEOFFSET
  1122. CONFIG_BOOTP_VENDOREX
  1123. CONFIG_BOOTP_MAY_FAIL
  1124. CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
  1125. environment variable, not the BOOTP server.
  1126. CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
  1127. after the configured retry count, the call will fail
  1128. instead of starting over. This can be used to fail over
  1129. to Link-local IP address configuration if the DHCP server
  1130. is not available.
  1131. CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
  1132. to do a dynamic update of a DNS server. To do this, they
  1133. need the hostname of the DHCP requester.
  1134. If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
  1135. of the "hostname" environment variable is passed as
  1136. option 12 to the DHCP server.
  1137. CONFIG_BOOTP_DHCP_REQUEST_DELAY
  1138. A 32bit value in microseconds for a delay between
  1139. receiving a "DHCP Offer" and sending the "DHCP Request".
  1140. This fixes a problem with certain DHCP servers that don't
  1141. respond 100% of the time to a "DHCP request". E.g. On an
  1142. AT91RM9200 processor running at 180MHz, this delay needed
  1143. to be *at least* 15,000 usec before a Windows Server 2003
  1144. DHCP server would reply 100% of the time. I recommend at
  1145. least 50,000 usec to be safe. The alternative is to hope
  1146. that one of the retries will be successful but note that
  1147. the DHCP timeout and retry process takes a longer than
  1148. this delay.
  1149. - Link-local IP address negotiation:
  1150. Negotiate with other link-local clients on the local network
  1151. for an address that doesn't require explicit configuration.
  1152. This is especially useful if a DHCP server cannot be guaranteed
  1153. to exist in all environments that the device must operate.
  1154. See doc/README.link-local for more information.
  1155. - MAC address from environment variables
  1156. FDT_SEQ_MACADDR_FROM_ENV
  1157. Fix-up device tree with MAC addresses fetched sequentially from
  1158. environment variables. This config work on assumption that
  1159. non-usable ethernet node of device-tree are either not present
  1160. or their status has been marked as "disabled".
  1161. - CDP Options:
  1162. CONFIG_CDP_DEVICE_ID
  1163. The device id used in CDP trigger frames.
  1164. CONFIG_CDP_DEVICE_ID_PREFIX
  1165. A two character string which is prefixed to the MAC address
  1166. of the device.
  1167. CONFIG_CDP_PORT_ID
  1168. A printf format string which contains the ascii name of
  1169. the port. Normally is set to "eth%d" which sets
  1170. eth0 for the first Ethernet, eth1 for the second etc.
  1171. CONFIG_CDP_CAPABILITIES
  1172. A 32bit integer which indicates the device capabilities;
  1173. 0x00000010 for a normal host which does not forwards.
  1174. CONFIG_CDP_VERSION
  1175. An ascii string containing the version of the software.
  1176. CONFIG_CDP_PLATFORM
  1177. An ascii string containing the name of the platform.
  1178. CONFIG_CDP_TRIGGER
  1179. A 32bit integer sent on the trigger.
  1180. CONFIG_CDP_POWER_CONSUMPTION
  1181. A 16bit integer containing the power consumption of the
  1182. device in .1 of milliwatts.
  1183. CONFIG_CDP_APPLIANCE_VLAN_TYPE
  1184. A byte containing the id of the VLAN.
  1185. - Status LED: CONFIG_LED_STATUS
  1186. Several configurations allow to display the current
  1187. status using a LED. For instance, the LED will blink
  1188. fast while running U-Boot code, stop blinking as
  1189. soon as a reply to a BOOTP request was received, and
  1190. start blinking slow once the Linux kernel is running
  1191. (supported by a status LED driver in the Linux
  1192. kernel). Defining CONFIG_LED_STATUS enables this
  1193. feature in U-Boot.
  1194. Additional options:
  1195. CONFIG_LED_STATUS_GPIO
  1196. The status LED can be connected to a GPIO pin.
  1197. In such cases, the gpio_led driver can be used as a
  1198. status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
  1199. to include the gpio_led driver in the U-Boot binary.
  1200. CONFIG_GPIO_LED_INVERTED_TABLE
  1201. Some GPIO connected LEDs may have inverted polarity in which
  1202. case the GPIO high value corresponds to LED off state and
  1203. GPIO low value corresponds to LED on state.
  1204. In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
  1205. with a list of GPIO LEDs that have inverted polarity.
  1206. - I2C Support: CONFIG_SYS_I2C
  1207. This enable the NEW i2c subsystem, and will allow you to use
  1208. i2c commands at the u-boot command line (as long as you set
  1209. CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
  1210. based realtime clock chips or other i2c devices. See
  1211. common/cmd_i2c.c for a description of the command line
  1212. interface.
  1213. ported i2c driver to the new framework:
  1214. - drivers/i2c/soft_i2c.c:
  1215. - activate first bus with CONFIG_SYS_I2C_SOFT define
  1216. CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
  1217. for defining speed and slave address
  1218. - activate second bus with I2C_SOFT_DECLARATIONS2 define
  1219. CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
  1220. for defining speed and slave address
  1221. - activate third bus with I2C_SOFT_DECLARATIONS3 define
  1222. CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
  1223. for defining speed and slave address
  1224. - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
  1225. CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
  1226. for defining speed and slave address
  1227. - drivers/i2c/fsl_i2c.c:
  1228. - activate i2c driver with CONFIG_SYS_I2C_FSL
  1229. define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
  1230. offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
  1231. CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
  1232. bus.
  1233. - If your board supports a second fsl i2c bus, define
  1234. CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
  1235. CONFIG_SYS_FSL_I2C2_SPEED for the speed and
  1236. CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
  1237. second bus.
  1238. - drivers/i2c/tegra_i2c.c:
  1239. - activate this driver with CONFIG_SYS_I2C_TEGRA
  1240. - This driver adds 4 i2c buses with a fix speed from
  1241. 100000 and the slave addr 0!
  1242. - drivers/i2c/ppc4xx_i2c.c
  1243. - activate this driver with CONFIG_SYS_I2C_PPC4XX
  1244. - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
  1245. - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
  1246. - drivers/i2c/i2c_mxc.c
  1247. - activate this driver with CONFIG_SYS_I2C_MXC
  1248. - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
  1249. - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
  1250. - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
  1251. - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
  1252. - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
  1253. - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
  1254. - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
  1255. - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
  1256. - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
  1257. - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
  1258. - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
  1259. - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
  1260. If those defines are not set, default value is 100000
  1261. for speed, and 0 for slave.
  1262. - drivers/i2c/rcar_i2c.c:
  1263. - activate this driver with CONFIG_SYS_I2C_RCAR
  1264. - This driver adds 4 i2c buses
  1265. - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
  1266. - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
  1267. - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
  1268. - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
  1269. - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
  1270. - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
  1271. - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
  1272. - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
  1273. - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
  1274. - drivers/i2c/sh_i2c.c:
  1275. - activate this driver with CONFIG_SYS_I2C_SH
  1276. - This driver adds from 2 to 5 i2c buses
  1277. - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
  1278. - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
  1279. - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
  1280. - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
  1281. - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
  1282. - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
  1283. - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
  1284. - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
  1285. - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
  1286. - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
  1287. - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
  1288. - drivers/i2c/omap24xx_i2c.c
  1289. - activate this driver with CONFIG_SYS_I2C_OMAP24XX
  1290. - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
  1291. - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
  1292. - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
  1293. - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
  1294. - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
  1295. - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
  1296. - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
  1297. - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
  1298. - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
  1299. - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
  1300. - drivers/i2c/zynq_i2c.c
  1301. - activate this driver with CONFIG_SYS_I2C_ZYNQ
  1302. - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
  1303. - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
  1304. - drivers/i2c/s3c24x0_i2c.c:
  1305. - activate this driver with CONFIG_SYS_I2C_S3C24X0
  1306. - This driver adds i2c buses (11 for Exynos5250, Exynos5420
  1307. 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
  1308. with a fix speed from 100000 and the slave addr 0!
  1309. - drivers/i2c/ihs_i2c.c
  1310. - activate this driver with CONFIG_SYS_I2C_IHS
  1311. - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
  1312. - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
  1313. - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
  1314. - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
  1315. - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
  1316. - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
  1317. - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
  1318. - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
  1319. - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
  1320. - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
  1321. - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
  1322. - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
  1323. - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
  1324. - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
  1325. - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
  1326. - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
  1327. - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
  1328. - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
  1329. - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
  1330. - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
  1331. - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
  1332. additional defines:
  1333. CONFIG_SYS_NUM_I2C_BUSES
  1334. Hold the number of i2c buses you want to use.
  1335. CONFIG_SYS_I2C_DIRECT_BUS
  1336. define this, if you don't use i2c muxes on your hardware.
  1337. if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
  1338. omit this define.
  1339. CONFIG_SYS_I2C_MAX_HOPS
  1340. define how many muxes are maximal consecutively connected
  1341. on one i2c bus. If you not use i2c muxes, omit this
  1342. define.
  1343. CONFIG_SYS_I2C_BUSES
  1344. hold a list of buses you want to use, only used if
  1345. CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
  1346. a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
  1347. CONFIG_SYS_NUM_I2C_BUSES = 9:
  1348. CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
  1349. {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
  1350. {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
  1351. {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
  1352. {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
  1353. {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
  1354. {1, {I2C_NULL_HOP}}, \
  1355. {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
  1356. {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
  1357. }
  1358. which defines
  1359. bus 0 on adapter 0 without a mux
  1360. bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
  1361. bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
  1362. bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
  1363. bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
  1364. bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
  1365. bus 6 on adapter 1 without a mux
  1366. bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
  1367. bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
  1368. If you do not have i2c muxes on your board, omit this define.
  1369. - Legacy I2C Support:
  1370. If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
  1371. then the following macros need to be defined (examples are
  1372. from include/configs/lwmon.h):
  1373. I2C_INIT
  1374. (Optional). Any commands necessary to enable the I2C
  1375. controller or configure ports.
  1376. eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
  1377. I2C_ACTIVE
  1378. The code necessary to make the I2C data line active
  1379. (driven). If the data line is open collector, this
  1380. define can be null.
  1381. eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
  1382. I2C_TRISTATE
  1383. The code necessary to make the I2C data line tri-stated
  1384. (inactive). If the data line is open collector, this
  1385. define can be null.
  1386. eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
  1387. I2C_READ
  1388. Code that returns true if the I2C data line is high,
  1389. false if it is low.
  1390. eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
  1391. I2C_SDA(bit)
  1392. If <bit> is true, sets the I2C data line high. If it
  1393. is false, it clears it (low).
  1394. eg: #define I2C_SDA(bit) \
  1395. if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
  1396. else immr->im_cpm.cp_pbdat &= ~PB_SDA
  1397. I2C_SCL(bit)
  1398. If <bit> is true, sets the I2C clock line high. If it
  1399. is false, it clears it (low).
  1400. eg: #define I2C_SCL(bit) \
  1401. if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
  1402. else immr->im_cpm.cp_pbdat &= ~PB_SCL
  1403. I2C_DELAY
  1404. This delay is invoked four times per clock cycle so this
  1405. controls the rate of data transfer. The data rate thus
  1406. is 1 / (I2C_DELAY * 4). Often defined to be something
  1407. like:
  1408. #define I2C_DELAY udelay(2)
  1409. CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
  1410. If your arch supports the generic GPIO framework (asm/gpio.h),
  1411. then you may alternatively define the two GPIOs that are to be
  1412. used as SCL / SDA. Any of the previous I2C_xxx macros will
  1413. have GPIO-based defaults assigned to them as appropriate.
  1414. You should define these to the GPIO value as given directly to
  1415. the generic GPIO functions.
  1416. CONFIG_SYS_I2C_INIT_BOARD
  1417. When a board is reset during an i2c bus transfer
  1418. chips might think that the current transfer is still
  1419. in progress. On some boards it is possible to access
  1420. the i2c SCLK line directly, either by using the
  1421. processor pin as a GPIO or by having a second pin
  1422. connected to the bus. If this option is defined a
  1423. custom i2c_init_board() routine in boards/xxx/board.c
  1424. is run early in the boot sequence.
  1425. CONFIG_I2C_MULTI_BUS
  1426. This option allows the use of multiple I2C buses, each of which
  1427. must have a controller. At any point in time, only one bus is
  1428. active. To switch to a different bus, use the 'i2c dev' command.
  1429. Note that bus numbering is zero-based.
  1430. CONFIG_SYS_I2C_NOPROBES
  1431. This option specifies a list of I2C devices that will be skipped
  1432. when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
  1433. is set, specify a list of bus-device pairs. Otherwise, specify
  1434. a 1D array of device addresses
  1435. e.g.
  1436. #undef CONFIG_I2C_MULTI_BUS
  1437. #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
  1438. will skip addresses 0x50 and 0x68 on a board with one I2C bus
  1439. #define CONFIG_I2C_MULTI_BUS
  1440. #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
  1441. will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
  1442. CONFIG_SYS_SPD_BUS_NUM
  1443. If defined, then this indicates the I2C bus number for DDR SPD.
  1444. If not defined, then U-Boot assumes that SPD is on I2C bus 0.
  1445. CONFIG_SYS_RTC_BUS_NUM
  1446. If defined, then this indicates the I2C bus number for the RTC.
  1447. If not defined, then U-Boot assumes that RTC is on I2C bus 0.
  1448. CONFIG_SOFT_I2C_READ_REPEATED_START
  1449. defining this will force the i2c_read() function in
  1450. the soft_i2c driver to perform an I2C repeated start
  1451. between writing the address pointer and reading the
  1452. data. If this define is omitted the default behaviour
  1453. of doing a stop-start sequence will be used. Most I2C
  1454. devices can use either method, but some require one or
  1455. the other.
  1456. - SPI Support: CONFIG_SPI
  1457. Enables SPI driver (so far only tested with
  1458. SPI EEPROM, also an instance works with Crystal A/D and
  1459. D/As on the SACSng board)
  1460. CONFIG_SOFT_SPI
  1461. Enables a software (bit-bang) SPI driver rather than
  1462. using hardware support. This is a general purpose
  1463. driver that only requires three general I/O port pins
  1464. (two outputs, one input) to function. If this is
  1465. defined, the board configuration must define several
  1466. SPI configuration items (port pins to use, etc). For
  1467. an example, see include/configs/sacsng.h.
  1468. CONFIG_HARD_SPI
  1469. Enables a hardware SPI driver for general-purpose reads
  1470. and writes. As with CONFIG_SOFT_SPI, the board configuration
  1471. must define a list of chip-select function pointers.
  1472. Currently supported on some MPC8xxx processors. For an
  1473. example, see include/configs/mpc8349emds.h.
  1474. CONFIG_SYS_SPI_MXC_WAIT
  1475. Timeout for waiting until spi transfer completed.
  1476. default: (CONFIG_SYS_HZ/100) /* 10 ms */
  1477. - FPGA Support: CONFIG_FPGA
  1478. Enables FPGA subsystem.
  1479. CONFIG_FPGA_<vendor>
  1480. Enables support for specific chip vendors.
  1481. (ALTERA, XILINX)
  1482. CONFIG_FPGA_<family>
  1483. Enables support for FPGA family.
  1484. (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
  1485. CONFIG_FPGA_COUNT
  1486. Specify the number of FPGA devices to support.
  1487. CONFIG_SYS_FPGA_PROG_FEEDBACK
  1488. Enable printing of hash marks during FPGA configuration.
  1489. CONFIG_SYS_FPGA_CHECK_BUSY
  1490. Enable checks on FPGA configuration interface busy
  1491. status by the configuration function. This option
  1492. will require a board or device specific function to
  1493. be written.
  1494. CONFIG_FPGA_DELAY
  1495. If defined, a function that provides delays in the FPGA
  1496. configuration driver.
  1497. CONFIG_SYS_FPGA_CHECK_CTRLC
  1498. Allow Control-C to interrupt FPGA configuration
  1499. CONFIG_SYS_FPGA_CHECK_ERROR
  1500. Check for configuration errors during FPGA bitfile
  1501. loading. For example, abort during Virtex II
  1502. configuration if the INIT_B line goes low (which
  1503. indicated a CRC error).
  1504. CONFIG_SYS_FPGA_WAIT_INIT
  1505. Maximum time to wait for the INIT_B line to de-assert
  1506. after PROB_B has been de-asserted during a Virtex II
  1507. FPGA configuration sequence. The default time is 500
  1508. ms.
  1509. CONFIG_SYS_FPGA_WAIT_BUSY
  1510. Maximum time to wait for BUSY to de-assert during
  1511. Virtex II FPGA configuration. The default is 5 ms.
  1512. CONFIG_SYS_FPGA_WAIT_CONFIG
  1513. Time to wait after FPGA configuration. The default is
  1514. 200 ms.
  1515. - Configuration Management:
  1516. CONFIG_BUILD_TARGET
  1517. Some SoCs need special image types (e.g. U-Boot binary
  1518. with a special header) as build targets. By defining
  1519. CONFIG_BUILD_TARGET in the SoC / board header, this
  1520. special image will be automatically built upon calling
  1521. make / buildman.
  1522. CONFIG_IDENT_STRING
  1523. If defined, this string will be added to the U-Boot
  1524. version information (U_BOOT_VERSION)
  1525. - Vendor Parameter Protection:
  1526. U-Boot considers the values of the environment
  1527. variables "serial#" (Board Serial Number) and
  1528. "ethaddr" (Ethernet Address) to be parameters that
  1529. are set once by the board vendor / manufacturer, and
  1530. protects these variables from casual modification by
  1531. the user. Once set, these variables are read-only,
  1532. and write or delete attempts are rejected. You can
  1533. change this behaviour:
  1534. If CONFIG_ENV_OVERWRITE is #defined in your config
  1535. file, the write protection for vendor parameters is
  1536. completely disabled. Anybody can change or delete
  1537. these parameters.
  1538. Alternatively, if you define _both_ an ethaddr in the
  1539. default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
  1540. Ethernet address is installed in the environment,
  1541. which can be changed exactly ONCE by the user. [The
  1542. serial# is unaffected by this, i. e. it remains
  1543. read-only.]
  1544. The same can be accomplished in a more flexible way
  1545. for any variable by configuring the type of access
  1546. to allow for those variables in the ".flags" variable
  1547. or define CONFIG_ENV_FLAGS_LIST_STATIC.
  1548. - Protected RAM:
  1549. CONFIG_PRAM
  1550. Define this variable to enable the reservation of
  1551. "protected RAM", i. e. RAM which is not overwritten
  1552. by U-Boot. Define CONFIG_PRAM to hold the number of
  1553. kB you want to reserve for pRAM. You can overwrite
  1554. this default value by defining an environment
  1555. variable "pram" to the number of kB you want to
  1556. reserve. Note that the board info structure will
  1557. still show the full amount of RAM. If pRAM is
  1558. reserved, a new environment variable "mem" will
  1559. automatically be defined to hold the amount of
  1560. remaining RAM in a form that can be passed as boot
  1561. argument to Linux, for instance like that:
  1562. setenv bootargs ... mem=\${mem}
  1563. saveenv
  1564. This way you can tell Linux not to use this memory,
  1565. either, which results in a memory region that will
  1566. not be affected by reboots.
  1567. *WARNING* If your board configuration uses automatic
  1568. detection of the RAM size, you must make sure that
  1569. this memory test is non-destructive. So far, the
  1570. following board configurations are known to be
  1571. "pRAM-clean":
  1572. IVMS8, IVML24, SPD8xx,
  1573. HERMES, IP860, RPXlite, LWMON,
  1574. FLAGADM
  1575. - Access to physical memory region (> 4GB)
  1576. Some basic support is provided for operations on memory not
  1577. normally accessible to U-Boot - e.g. some architectures
  1578. support access to more than 4GB of memory on 32-bit
  1579. machines using physical address extension or similar.
  1580. Define CONFIG_PHYSMEM to access this basic support, which
  1581. currently only supports clearing the memory.
  1582. - Error Recovery:
  1583. CONFIG_NET_RETRY_COUNT
  1584. This variable defines the number of retries for
  1585. network operations like ARP, RARP, TFTP, or BOOTP
  1586. before giving up the operation. If not defined, a
  1587. default value of 5 is used.
  1588. CONFIG_ARP_TIMEOUT
  1589. Timeout waiting for an ARP reply in milliseconds.
  1590. CONFIG_NFS_TIMEOUT
  1591. Timeout in milliseconds used in NFS protocol.
  1592. If you encounter "ERROR: Cannot umount" in nfs command,
  1593. try longer timeout such as
  1594. #define CONFIG_NFS_TIMEOUT 10000UL
  1595. - Command Interpreter:
  1596. CONFIG_SYS_PROMPT_HUSH_PS2
  1597. This defines the secondary prompt string, which is
  1598. printed when the command interpreter needs more input
  1599. to complete a command. Usually "> ".
  1600. Note:
  1601. In the current implementation, the local variables
  1602. space and global environment variables space are
  1603. separated. Local variables are those you define by
  1604. simply typing `name=value'. To access a local
  1605. variable later on, you have write `$name' or
  1606. `${name}'; to execute the contents of a variable
  1607. directly type `$name' at the command prompt.
  1608. Global environment variables are those you use
  1609. setenv/printenv to work with. To run a command stored
  1610. in such a variable, you need to use the run command,
  1611. and you must not use the '$' sign to access them.
  1612. To store commands and special characters in a
  1613. variable, please use double quotation marks
  1614. surrounding the whole text of the variable, instead
  1615. of the backslashes before semicolons and special
  1616. symbols.
  1617. - Command Line Editing and History:
  1618. CONFIG_CMDLINE_PS_SUPPORT
  1619. Enable support for changing the command prompt string
  1620. at run-time. Only static string is supported so far.
  1621. The string is obtained from environment variables PS1
  1622. and PS2.
  1623. - Default Environment:
  1624. CONFIG_EXTRA_ENV_SETTINGS
  1625. Define this to contain any number of null terminated
  1626. strings (variable = value pairs) that will be part of
  1627. the default environment compiled into the boot image.
  1628. For example, place something like this in your
  1629. board's config file:
  1630. #define CONFIG_EXTRA_ENV_SETTINGS \
  1631. "myvar1=value1\0" \
  1632. "myvar2=value2\0"
  1633. Warning: This method is based on knowledge about the
  1634. internal format how the environment is stored by the
  1635. U-Boot code. This is NOT an official, exported
  1636. interface! Although it is unlikely that this format
  1637. will change soon, there is no guarantee either.
  1638. You better know what you are doing here.
  1639. Note: overly (ab)use of the default environment is
  1640. discouraged. Make sure to check other ways to preset
  1641. the environment like the "source" command or the
  1642. boot command first.
  1643. CONFIG_DELAY_ENVIRONMENT
  1644. Normally the environment is loaded when the board is
  1645. initialised so that it is available to U-Boot. This inhibits
  1646. that so that the environment is not available until
  1647. explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
  1648. this is instead controlled by the value of
  1649. /config/load-environment.
  1650. - Serial Flash support
  1651. Usage requires an initial 'sf probe' to define the serial
  1652. flash parameters, followed by read/write/erase/update
  1653. commands.
  1654. The following defaults may be provided by the platform
  1655. to handle the common case when only a single serial
  1656. flash is present on the system.
  1657. CONFIG_SF_DEFAULT_BUS Bus identifier
  1658. CONFIG_SF_DEFAULT_CS Chip-select
  1659. CONFIG_SF_DEFAULT_MODE (see include/spi.h)
  1660. CONFIG_SF_DEFAULT_SPEED in Hz
  1661. - TFTP Fixed UDP Port:
  1662. CONFIG_TFTP_PORT
  1663. If this is defined, the environment variable tftpsrcp
  1664. is used to supply the TFTP UDP source port value.
  1665. If tftpsrcp isn't defined, the normal pseudo-random port
  1666. number generator is used.
  1667. Also, the environment variable tftpdstp is used to supply
  1668. the TFTP UDP destination port value. If tftpdstp isn't
  1669. defined, the normal port 69 is used.
  1670. The purpose for tftpsrcp is to allow a TFTP server to
  1671. blindly start the TFTP transfer using the pre-configured
  1672. target IP address and UDP port. This has the effect of
  1673. "punching through" the (Windows XP) firewall, allowing
  1674. the remainder of the TFTP transfer to proceed normally.
  1675. A better solution is to properly configure the firewall,
  1676. but sometimes that is not allowed.
  1677. - Show boot progress:
  1678. CONFIG_SHOW_BOOT_PROGRESS
  1679. Defining this option allows to add some board-
  1680. specific code (calling a user-provided function
  1681. "show_boot_progress(int)") that enables you to show
  1682. the system's boot progress on some display (for
  1683. example, some LED's) on your board. At the moment,
  1684. the following checkpoints are implemented:
  1685. Legacy uImage format:
  1686. Arg Where When
  1687. 1 common/cmd_bootm.c before attempting to boot an image
  1688. -1 common/cmd_bootm.c Image header has bad magic number
  1689. 2 common/cmd_bootm.c Image header has correct magic number
  1690. -2 common/cmd_bootm.c Image header has bad checksum
  1691. 3 common/cmd_bootm.c Image header has correct checksum
  1692. -3 common/cmd_bootm.c Image data has bad checksum
  1693. 4 common/cmd_bootm.c Image data has correct checksum
  1694. -4 common/cmd_bootm.c Image is for unsupported architecture
  1695. 5 common/cmd_bootm.c Architecture check OK
  1696. -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
  1697. 6 common/cmd_bootm.c Image Type check OK
  1698. -6 common/cmd_bootm.c gunzip uncompression error
  1699. -7 common/cmd_bootm.c Unimplemented compression type
  1700. 7 common/cmd_bootm.c Uncompression OK
  1701. 8 common/cmd_bootm.c No uncompress/copy overwrite error
  1702. -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
  1703. 9 common/image.c Start initial ramdisk verification
  1704. -10 common/image.c Ramdisk header has bad magic number
  1705. -11 common/image.c Ramdisk header has bad checksum
  1706. 10 common/image.c Ramdisk header is OK
  1707. -12 common/image.c Ramdisk data has bad checksum
  1708. 11 common/image.c Ramdisk data has correct checksum
  1709. 12 common/image.c Ramdisk verification complete, start loading
  1710. -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
  1711. 13 common/image.c Start multifile image verification
  1712. 14 common/image.c No initial ramdisk, no multifile, continue.
  1713. 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
  1714. -30 arch/powerpc/lib/board.c Fatal error, hang the system
  1715. -31 post/post.c POST test failed, detected by post_output_backlog()
  1716. -32 post/post.c POST test failed, detected by post_run_single()
  1717. 34 common/cmd_doc.c before loading a Image from a DOC device
  1718. -35 common/cmd_doc.c Bad usage of "doc" command
  1719. 35 common/cmd_doc.c correct usage of "doc" command
  1720. -36 common/cmd_doc.c No boot device
  1721. 36 common/cmd_doc.c correct boot device
  1722. -37 common/cmd_doc.c Unknown Chip ID on boot device
  1723. 37 common/cmd_doc.c correct chip ID found, device available
  1724. -38 common/cmd_doc.c Read Error on boot device
  1725. 38 common/cmd_doc.c reading Image header from DOC device OK
  1726. -39 common/cmd_doc.c Image header has bad magic number
  1727. 39 common/cmd_doc.c Image header has correct magic number
  1728. -40 common/cmd_doc.c Error reading Image from DOC device
  1729. 40 common/cmd_doc.c Image header has correct magic number
  1730. 41 common/cmd_ide.c before loading a Image from a IDE device
  1731. -42 common/cmd_ide.c Bad usage of "ide" command
  1732. 42 common/cmd_ide.c correct usage of "ide" command
  1733. -43 common/cmd_ide.c No boot device
  1734. 43 common/cmd_ide.c boot device found
  1735. -44 common/cmd_ide.c Device not available
  1736. 44 common/cmd_ide.c Device available
  1737. -45 common/cmd_ide.c wrong partition selected
  1738. 45 common/cmd_ide.c partition selected
  1739. -46 common/cmd_ide.c Unknown partition table
  1740. 46 common/cmd_ide.c valid partition table found
  1741. -47 common/cmd_ide.c Invalid partition type
  1742. 47 common/cmd_ide.c correct partition type
  1743. -48 common/cmd_ide.c Error reading Image Header on boot device
  1744. 48 common/cmd_ide.c reading Image Header from IDE device OK
  1745. -49 common/cmd_ide.c Image header has bad magic number
  1746. 49 common/cmd_ide.c Image header has correct magic number
  1747. -50 common/cmd_ide.c Image header has bad checksum
  1748. 50 common/cmd_ide.c Image header has correct checksum
  1749. -51 common/cmd_ide.c Error reading Image from IDE device
  1750. 51 common/cmd_ide.c reading Image from IDE device OK
  1751. 52 common/cmd_nand.c before loading a Image from a NAND device
  1752. -53 common/cmd_nand.c Bad usage of "nand" command
  1753. 53 common/cmd_nand.c correct usage of "nand" command
  1754. -54 common/cmd_nand.c No boot device
  1755. 54 common/cmd_nand.c boot device found
  1756. -55 common/cmd_nand.c Unknown Chip ID on boot device
  1757. 55 common/cmd_nand.c correct chip ID found, device available
  1758. -56 common/cmd_nand.c Error reading Image Header on boot device
  1759. 56 common/cmd_nand.c reading Image Header from NAND device OK
  1760. -57 common/cmd_nand.c Image header has bad magic number
  1761. 57 common/cmd_nand.c Image header has correct magic number
  1762. -58 common/cmd_nand.c Error reading Image from NAND device
  1763. 58 common/cmd_nand.c reading Image from NAND device OK
  1764. -60 common/env_common.c Environment has a bad CRC, using default
  1765. 64 net/eth.c starting with Ethernet configuration.
  1766. -64 net/eth.c no Ethernet found.
  1767. 65 net/eth.c Ethernet found.
  1768. -80 common/cmd_net.c usage wrong
  1769. 80 common/cmd_net.c before calling net_loop()
  1770. -81 common/cmd_net.c some error in net_loop() occurred
  1771. 81 common/cmd_net.c net_loop() back without error
  1772. -82 common/cmd_net.c size == 0 (File with size 0 loaded)
  1773. 82 common/cmd_net.c trying automatic boot
  1774. 83 common/cmd_net.c running "source" command
  1775. -83 common/cmd_net.c some error in automatic boot or "source" command
  1776. 84 common/cmd_net.c end without errors
  1777. FIT uImage format:
  1778. Arg Where When
  1779. 100 common/cmd_bootm.c Kernel FIT Image has correct format
  1780. -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
  1781. 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
  1782. -101 common/cmd_bootm.c Can't get configuration for kernel subimage
  1783. 102 common/cmd_bootm.c Kernel unit name specified
  1784. -103 common/cmd_bootm.c Can't get kernel subimage node offset
  1785. 103 common/cmd_bootm.c Found configuration node
  1786. 104 common/cmd_bootm.c Got kernel subimage node offset
  1787. -104 common/cmd_bootm.c Kernel subimage hash verification failed
  1788. 105 common/cmd_bootm.c Kernel subimage hash verification OK
  1789. -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
  1790. 106 common/cmd_bootm.c Architecture check OK
  1791. -106 common/cmd_bootm.c Kernel subimage has wrong type
  1792. 107 common/cmd_bootm.c Kernel subimage type OK
  1793. -107 common/cmd_bootm.c Can't get kernel subimage data/size
  1794. 108 common/cmd_bootm.c Got kernel subimage data/size
  1795. -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
  1796. -109 common/cmd_bootm.c Can't get kernel subimage type
  1797. -110 common/cmd_bootm.c Can't get kernel subimage comp
  1798. -111 common/cmd_bootm.c Can't get kernel subimage os
  1799. -112 common/cmd_bootm.c Can't get kernel subimage load address
  1800. -113 common/cmd_bootm.c Image uncompress/copy overwrite error
  1801. 120 common/image.c Start initial ramdisk verification
  1802. -120 common/image.c Ramdisk FIT image has incorrect format
  1803. 121 common/image.c Ramdisk FIT image has correct format
  1804. 122 common/image.c No ramdisk subimage unit name, using configuration
  1805. -122 common/image.c Can't get configuration for ramdisk subimage
  1806. 123 common/image.c Ramdisk unit name specified
  1807. -124 common/image.c Can't get ramdisk subimage node offset
  1808. 125 common/image.c Got ramdisk subimage node offset
  1809. -125 common/image.c Ramdisk subimage hash verification failed
  1810. 126 common/image.c Ramdisk subimage hash verification OK
  1811. -126 common/image.c Ramdisk subimage for unsupported architecture
  1812. 127 common/image.c Architecture check OK
  1813. -127 common/image.c Can't get ramdisk subimage data/size
  1814. 128 common/image.c Got ramdisk subimage data/size
  1815. 129 common/image.c Can't get ramdisk load address
  1816. -129 common/image.c Got ramdisk load address
  1817. -130 common/cmd_doc.c Incorrect FIT image format
  1818. 131 common/cmd_doc.c FIT image format OK
  1819. -140 common/cmd_ide.c Incorrect FIT image format
  1820. 141 common/cmd_ide.c FIT image format OK
  1821. -150 common/cmd_nand.c Incorrect FIT image format
  1822. 151 common/cmd_nand.c FIT image format OK
  1823. - Standalone program support:
  1824. CONFIG_STANDALONE_LOAD_ADDR
  1825. This option defines a board specific value for the
  1826. address where standalone program gets loaded, thus
  1827. overwriting the architecture dependent default
  1828. settings.
  1829. - Frame Buffer Address:
  1830. CONFIG_FB_ADDR
  1831. Define CONFIG_FB_ADDR if you want to use specific
  1832. address for frame buffer. This is typically the case
  1833. when using a graphics controller has separate video
  1834. memory. U-Boot will then place the frame buffer at
  1835. the given address instead of dynamically reserving it
  1836. in system RAM by calling lcd_setmem(), which grabs
  1837. the memory for the frame buffer depending on the
  1838. configured panel size.
  1839. Please see board_init_f function.
  1840. - Automatic software updates via TFTP server
  1841. CONFIG_UPDATE_TFTP
  1842. CONFIG_UPDATE_TFTP_CNT_MAX
  1843. CONFIG_UPDATE_TFTP_MSEC_MAX
  1844. These options enable and control the auto-update feature;
  1845. for a more detailed description refer to doc/README.update.
  1846. - MTD Support (mtdparts command, UBI support)
  1847. CONFIG_MTD_UBI_WL_THRESHOLD
  1848. This parameter defines the maximum difference between the highest
  1849. erase counter value and the lowest erase counter value of eraseblocks
  1850. of UBI devices. When this threshold is exceeded, UBI starts performing
  1851. wear leveling by means of moving data from eraseblock with low erase
  1852. counter to eraseblocks with high erase counter.
  1853. The default value should be OK for SLC NAND flashes, NOR flashes and
  1854. other flashes which have eraseblock life-cycle 100000 or more.
  1855. However, in case of MLC NAND flashes which typically have eraseblock
  1856. life-cycle less than 10000, the threshold should be lessened (e.g.,
  1857. to 128 or 256, although it does not have to be power of 2).
  1858. default: 4096
  1859. CONFIG_MTD_UBI_BEB_LIMIT
  1860. This option specifies the maximum bad physical eraseblocks UBI
  1861. expects on the MTD device (per 1024 eraseblocks). If the
  1862. underlying flash does not admit of bad eraseblocks (e.g. NOR
  1863. flash), this value is ignored.
  1864. NAND datasheets often specify the minimum and maximum NVM
  1865. (Number of Valid Blocks) for the flashes' endurance lifetime.
  1866. The maximum expected bad eraseblocks per 1024 eraseblocks
  1867. then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
  1868. which gives 20 for most NANDs (MaxNVB is basically the total
  1869. count of eraseblocks on the chip).
  1870. To put it differently, if this value is 20, UBI will try to
  1871. reserve about 1.9% of physical eraseblocks for bad blocks
  1872. handling. And that will be 1.9% of eraseblocks on the entire
  1873. NAND chip, not just the MTD partition UBI attaches. This means
  1874. that if you have, say, a NAND flash chip admits maximum 40 bad
  1875. eraseblocks, and it is split on two MTD partitions of the same
  1876. size, UBI will reserve 40 eraseblocks when attaching a
  1877. partition.
  1878. default: 20
  1879. CONFIG_MTD_UBI_FASTMAP
  1880. Fastmap is a mechanism which allows attaching an UBI device
  1881. in nearly constant time. Instead of scanning the whole MTD device it
  1882. only has to locate a checkpoint (called fastmap) on the device.
  1883. The on-flash fastmap contains all information needed to attach
  1884. the device. Using fastmap makes only sense on large devices where
  1885. attaching by scanning takes long. UBI will not automatically install
  1886. a fastmap on old images, but you can set the UBI parameter
  1887. CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
  1888. that fastmap-enabled images are still usable with UBI implementations
  1889. without fastmap support. On typical flash devices the whole fastmap
  1890. fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
  1891. CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
  1892. Set this parameter to enable fastmap automatically on images
  1893. without a fastmap.
  1894. default: 0
  1895. CONFIG_MTD_UBI_FM_DEBUG
  1896. Enable UBI fastmap debug
  1897. default: 0
  1898. - SPL framework
  1899. CONFIG_SPL
  1900. Enable building of SPL globally.
  1901. CONFIG_SPL_LDSCRIPT
  1902. LDSCRIPT for linking the SPL binary.
  1903. CONFIG_SPL_MAX_FOOTPRINT
  1904. Maximum size in memory allocated to the SPL, BSS included.
  1905. When defined, the linker checks that the actual memory
  1906. used by SPL from _start to __bss_end does not exceed it.
  1907. CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
  1908. must not be both defined at the same time.
  1909. CONFIG_SPL_MAX_SIZE
  1910. Maximum size of the SPL image (text, data, rodata, and
  1911. linker lists sections), BSS excluded.
  1912. When defined, the linker checks that the actual size does
  1913. not exceed it.
  1914. CONFIG_SPL_TEXT_BASE
  1915. TEXT_BASE for linking the SPL binary.
  1916. CONFIG_SPL_RELOC_TEXT_BASE
  1917. Address to relocate to. If unspecified, this is equal to
  1918. CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
  1919. CONFIG_SPL_BSS_START_ADDR
  1920. Link address for the BSS within the SPL binary.
  1921. CONFIG_SPL_BSS_MAX_SIZE
  1922. Maximum size in memory allocated to the SPL BSS.
  1923. When defined, the linker checks that the actual memory used
  1924. by SPL from __bss_start to __bss_end does not exceed it.
  1925. CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
  1926. must not be both defined at the same time.
  1927. CONFIG_SPL_STACK
  1928. Adress of the start of the stack SPL will use
  1929. CONFIG_SPL_PANIC_ON_RAW_IMAGE
  1930. When defined, SPL will panic() if the image it has
  1931. loaded does not have a signature.
  1932. Defining this is useful when code which loads images
  1933. in SPL cannot guarantee that absolutely all read errors
  1934. will be caught.
  1935. An example is the LPC32XX MLC NAND driver, which will
  1936. consider that a completely unreadable NAND block is bad,
  1937. and thus should be skipped silently.
  1938. CONFIG_SPL_RELOC_STACK
  1939. Adress of the start of the stack SPL will use after
  1940. relocation. If unspecified, this is equal to
  1941. CONFIG_SPL_STACK.
  1942. CONFIG_SYS_SPL_MALLOC_START
  1943. Starting address of the malloc pool used in SPL.
  1944. When this option is set the full malloc is used in SPL and
  1945. it is set up by spl_init() and before that, the simple malloc()
  1946. can be used if CONFIG_SYS_MALLOC_F is defined.
  1947. CONFIG_SYS_SPL_MALLOC_SIZE
  1948. The size of the malloc pool used in SPL.
  1949. CONFIG_SPL_OS_BOOT
  1950. Enable booting directly to an OS from SPL.
  1951. See also: doc/README.falcon
  1952. CONFIG_SPL_DISPLAY_PRINT
  1953. For ARM, enable an optional function to print more information
  1954. about the running system.
  1955. CONFIG_SPL_INIT_MINIMAL
  1956. Arch init code should be built for a very small image
  1957. CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
  1958. Partition on the MMC to load U-Boot from when the MMC is being
  1959. used in raw mode
  1960. CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
  1961. Sector to load kernel uImage from when MMC is being
  1962. used in raw mode (for Falcon mode)
  1963. CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
  1964. CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
  1965. Sector and number of sectors to load kernel argument
  1966. parameters from when MMC is being used in raw mode
  1967. (for falcon mode)
  1968. CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
  1969. Partition on the MMC to load U-Boot from when the MMC is being
  1970. used in fs mode
  1971. CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
  1972. Filename to read to load U-Boot when reading from filesystem
  1973. CONFIG_SPL_FS_LOAD_KERNEL_NAME
  1974. Filename to read to load kernel uImage when reading
  1975. from filesystem (for Falcon mode)
  1976. CONFIG_SPL_FS_LOAD_ARGS_NAME
  1977. Filename to read to load kernel argument parameters
  1978. when reading from filesystem (for Falcon mode)
  1979. CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
  1980. Set this for NAND SPL on PPC mpc83xx targets, so that
  1981. start.S waits for the rest of the SPL to load before
  1982. continuing (the hardware starts execution after just
  1983. loading the first page rather than the full 4K).
  1984. CONFIG_SPL_SKIP_RELOCATE
  1985. Avoid SPL relocation
  1986. CONFIG_SPL_NAND_BASE
  1987. Include nand_base.c in the SPL. Requires
  1988. CONFIG_SPL_NAND_DRIVERS.
  1989. CONFIG_SPL_NAND_DRIVERS
  1990. SPL uses normal NAND drivers, not minimal drivers.
  1991. CONFIG_SPL_NAND_IDENT
  1992. SPL uses the chip ID list to identify the NAND flash.
  1993. Requires CONFIG_SPL_NAND_BASE.
  1994. CONFIG_SPL_NAND_ECC
  1995. Include standard software ECC in the SPL
  1996. CONFIG_SPL_NAND_SIMPLE
  1997. Support for NAND boot using simple NAND drivers that
  1998. expose the cmd_ctrl() interface.
  1999. CONFIG_SPL_UBI
  2000. Support for a lightweight UBI (fastmap) scanner and
  2001. loader
  2002. CONFIG_SPL_NAND_RAW_ONLY
  2003. Support to boot only raw u-boot.bin images. Use this only
  2004. if you need to save space.
  2005. CONFIG_SPL_COMMON_INIT_DDR
  2006. Set for common ddr init with serial presence detect in
  2007. SPL binary.
  2008. CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
  2009. CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
  2010. CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
  2011. CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
  2012. CONFIG_SYS_NAND_ECCBYTES
  2013. Defines the size and behavior of the NAND that SPL uses
  2014. to read U-Boot
  2015. CONFIG_SPL_NAND_BOOT
  2016. Add support NAND boot
  2017. CONFIG_SYS_NAND_U_BOOT_OFFS
  2018. Location in NAND to read U-Boot from
  2019. CONFIG_SYS_NAND_U_BOOT_DST
  2020. Location in memory to load U-Boot to
  2021. CONFIG_SYS_NAND_U_BOOT_SIZE
  2022. Size of image to load
  2023. CONFIG_SYS_NAND_U_BOOT_START
  2024. Entry point in loaded image to jump to
  2025. CONFIG_SYS_NAND_HW_ECC_OOBFIRST
  2026. Define this if you need to first read the OOB and then the
  2027. data. This is used, for example, on davinci platforms.
  2028. CONFIG_SPL_RAM_DEVICE
  2029. Support for running image already present in ram, in SPL binary
  2030. CONFIG_SPL_PAD_TO
  2031. Image offset to which the SPL should be padded before appending
  2032. the SPL payload. By default, this is defined as
  2033. CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
  2034. CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
  2035. payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
  2036. CONFIG_SPL_TARGET
  2037. Final target image containing SPL and payload. Some SPLs
  2038. use an arch-specific makefile fragment instead, for
  2039. example if more than one image needs to be produced.
  2040. CONFIG_SPL_FIT_PRINT
  2041. Printing information about a FIT image adds quite a bit of
  2042. code to SPL. So this is normally disabled in SPL. Use this
  2043. option to re-enable it. This will affect the output of the
  2044. bootm command when booting a FIT image.
  2045. - TPL framework
  2046. CONFIG_TPL
  2047. Enable building of TPL globally.
  2048. CONFIG_TPL_PAD_TO
  2049. Image offset to which the TPL should be padded before appending
  2050. the TPL payload. By default, this is defined as
  2051. CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
  2052. CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
  2053. payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
  2054. - Interrupt support (PPC):
  2055. There are common interrupt_init() and timer_interrupt()
  2056. for all PPC archs. interrupt_init() calls interrupt_init_cpu()
  2057. for CPU specific initialization. interrupt_init_cpu()
  2058. should set decrementer_count to appropriate value. If
  2059. CPU resets decrementer automatically after interrupt
  2060. (ppc4xx) it should set decrementer_count to zero.
  2061. timer_interrupt() calls timer_interrupt_cpu() for CPU
  2062. specific handling. If board has watchdog / status_led
  2063. / other_activity_monitor it works automatically from
  2064. general timer_interrupt().
  2065. Board initialization settings:
  2066. ------------------------------
  2067. During Initialization u-boot calls a number of board specific functions
  2068. to allow the preparation of board specific prerequisites, e.g. pin setup
  2069. before drivers are initialized. To enable these callbacks the
  2070. following configuration macros have to be defined. Currently this is
  2071. architecture specific, so please check arch/your_architecture/lib/board.c
  2072. typically in board_init_f() and board_init_r().
  2073. - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
  2074. - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
  2075. - CONFIG_BOARD_LATE_INIT: Call board_late_init()
  2076. - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
  2077. Configuration Settings:
  2078. -----------------------
  2079. - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
  2080. Optionally it can be defined to support 64-bit memory commands.
  2081. - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
  2082. undefine this when you're short of memory.
  2083. - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
  2084. width of the commands listed in the 'help' command output.
  2085. - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
  2086. prompt for user input.
  2087. - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
  2088. - CONFIG_SYS_PBSIZE: Buffer size for Console output
  2089. - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
  2090. - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
  2091. the application (usually a Linux kernel) when it is
  2092. booted
  2093. - CONFIG_SYS_BAUDRATE_TABLE:
  2094. List of legal baudrate settings for this board.
  2095. - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
  2096. Begin and End addresses of the area used by the
  2097. simple memory test.
  2098. - CONFIG_SYS_MEMTEST_SCRATCH:
  2099. Scratch address used by the alternate memory test
  2100. You only need to set this if address zero isn't writeable
  2101. - CONFIG_SYS_MEM_RESERVE_SECURE
  2102. Only implemented for ARMv8 for now.
  2103. If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
  2104. is substracted from total RAM and won't be reported to OS.
  2105. This memory can be used as secure memory. A variable
  2106. gd->arch.secure_ram is used to track the location. In systems
  2107. the RAM base is not zero, or RAM is divided into banks,
  2108. this variable needs to be recalcuated to get the address.
  2109. - CONFIG_SYS_MEM_TOP_HIDE:
  2110. If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
  2111. this specified memory area will get subtracted from the top
  2112. (end) of RAM and won't get "touched" at all by U-Boot. By
  2113. fixing up gd->ram_size the Linux kernel should gets passed
  2114. the now "corrected" memory size and won't touch it either.
  2115. This should work for arch/ppc and arch/powerpc. Only Linux
  2116. board ports in arch/powerpc with bootwrapper support that
  2117. recalculate the memory size from the SDRAM controller setup
  2118. will have to get fixed in Linux additionally.
  2119. This option can be used as a workaround for the 440EPx/GRx
  2120. CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
  2121. be touched.
  2122. WARNING: Please make sure that this value is a multiple of
  2123. the Linux page size (normally 4k). If this is not the case,
  2124. then the end address of the Linux memory will be located at a
  2125. non page size aligned address and this could cause major
  2126. problems.
  2127. - CONFIG_SYS_LOADS_BAUD_CHANGE:
  2128. Enable temporary baudrate change while serial download
  2129. - CONFIG_SYS_SDRAM_BASE:
  2130. Physical start address of SDRAM. _Must_ be 0 here.
  2131. - CONFIG_SYS_FLASH_BASE:
  2132. Physical start address of Flash memory.
  2133. - CONFIG_SYS_MONITOR_BASE:
  2134. Physical start address of boot monitor code (set by
  2135. make config files to be same as the text base address
  2136. (CONFIG_SYS_TEXT_BASE) used when linking) - same as
  2137. CONFIG_SYS_FLASH_BASE when booting from flash.
  2138. - CONFIG_SYS_MONITOR_LEN:
  2139. Size of memory reserved for monitor code, used to
  2140. determine _at_compile_time_ (!) if the environment is
  2141. embedded within the U-Boot image, or in a separate
  2142. flash sector.
  2143. - CONFIG_SYS_MALLOC_LEN:
  2144. Size of DRAM reserved for malloc() use.
  2145. - CONFIG_SYS_MALLOC_F_LEN
  2146. Size of the malloc() pool for use before relocation. If
  2147. this is defined, then a very simple malloc() implementation
  2148. will become available before relocation. The address is just
  2149. below the global data, and the stack is moved down to make
  2150. space.
  2151. This feature allocates regions with increasing addresses
  2152. within the region. calloc() is supported, but realloc()
  2153. is not available. free() is supported but does nothing.
  2154. The memory will be freed (or in fact just forgotten) when
  2155. U-Boot relocates itself.
  2156. - CONFIG_SYS_MALLOC_SIMPLE
  2157. Provides a simple and small malloc() and calloc() for those
  2158. boards which do not use the full malloc in SPL (which is
  2159. enabled with CONFIG_SYS_SPL_MALLOC_START).
  2160. - CONFIG_SYS_NONCACHED_MEMORY:
  2161. Size of non-cached memory area. This area of memory will be
  2162. typically located right below the malloc() area and mapped
  2163. uncached in the MMU. This is useful for drivers that would
  2164. otherwise require a lot of explicit cache maintenance. For
  2165. some drivers it's also impossible to properly maintain the
  2166. cache. For example if the regions that need to be flushed
  2167. are not a multiple of the cache-line size, *and* padding
  2168. cannot be allocated between the regions to align them (i.e.
  2169. if the HW requires a contiguous array of regions, and the
  2170. size of each region is not cache-aligned), then a flush of
  2171. one region may result in overwriting data that hardware has
  2172. written to another region in the same cache-line. This can
  2173. happen for example in network drivers where descriptors for
  2174. buffers are typically smaller than the CPU cache-line (e.g.
  2175. 16 bytes vs. 32 or 64 bytes).
  2176. Non-cached memory is only supported on 32-bit ARM at present.
  2177. - CONFIG_SYS_BOOTM_LEN:
  2178. Normally compressed uImages are limited to an
  2179. uncompressed size of 8 MBytes. If this is not enough,
  2180. you can define CONFIG_SYS_BOOTM_LEN in your board config file
  2181. to adjust this setting to your needs.
  2182. - CONFIG_SYS_BOOTMAPSZ:
  2183. Maximum size of memory mapped by the startup code of
  2184. the Linux kernel; all data that must be processed by
  2185. the Linux kernel (bd_info, boot arguments, FDT blob if
  2186. used) must be put below this limit, unless "bootm_low"
  2187. environment variable is defined and non-zero. In such case
  2188. all data for the Linux kernel must be between "bootm_low"
  2189. and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
  2190. variable "bootm_mapsize" will override the value of
  2191. CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
  2192. then the value in "bootm_size" will be used instead.
  2193. - CONFIG_SYS_BOOT_RAMDISK_HIGH:
  2194. Enable initrd_high functionality. If defined then the
  2195. initrd_high feature is enabled and the bootm ramdisk subcommand
  2196. is enabled.
  2197. - CONFIG_SYS_BOOT_GET_CMDLINE:
  2198. Enables allocating and saving kernel cmdline in space between
  2199. "bootm_low" and "bootm_low" + BOOTMAPSZ.
  2200. - CONFIG_SYS_BOOT_GET_KBD:
  2201. Enables allocating and saving a kernel copy of the bd_info in
  2202. space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
  2203. - CONFIG_SYS_MAX_FLASH_BANKS:
  2204. Max number of Flash memory banks
  2205. - CONFIG_SYS_MAX_FLASH_SECT:
  2206. Max number of sectors on a Flash chip
  2207. - CONFIG_SYS_FLASH_ERASE_TOUT:
  2208. Timeout for Flash erase operations (in ms)
  2209. - CONFIG_SYS_FLASH_WRITE_TOUT:
  2210. Timeout for Flash write operations (in ms)
  2211. - CONFIG_SYS_FLASH_LOCK_TOUT
  2212. Timeout for Flash set sector lock bit operation (in ms)
  2213. - CONFIG_SYS_FLASH_UNLOCK_TOUT
  2214. Timeout for Flash clear lock bits operation (in ms)
  2215. - CONFIG_SYS_FLASH_PROTECTION
  2216. If defined, hardware flash sectors protection is used
  2217. instead of U-Boot software protection.
  2218. - CONFIG_SYS_DIRECT_FLASH_TFTP:
  2219. Enable TFTP transfers directly to flash memory;
  2220. without this option such a download has to be
  2221. performed in two steps: (1) download to RAM, and (2)
  2222. copy from RAM to flash.
  2223. The two-step approach is usually more reliable, since
  2224. you can check if the download worked before you erase
  2225. the flash, but in some situations (when system RAM is
  2226. too limited to allow for a temporary copy of the
  2227. downloaded image) this option may be very useful.
  2228. - CONFIG_SYS_FLASH_CFI:
  2229. Define if the flash driver uses extra elements in the
  2230. common flash structure for storing flash geometry.
  2231. - CONFIG_FLASH_CFI_DRIVER
  2232. This option also enables the building of the cfi_flash driver
  2233. in the drivers directory
  2234. - CONFIG_FLASH_CFI_MTD
  2235. This option enables the building of the cfi_mtd driver
  2236. in the drivers directory. The driver exports CFI flash
  2237. to the MTD layer.
  2238. - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
  2239. Use buffered writes to flash.
  2240. - CONFIG_FLASH_SPANSION_S29WS_N
  2241. s29ws-n MirrorBit flash has non-standard addresses for buffered
  2242. write commands.
  2243. - CONFIG_SYS_FLASH_QUIET_TEST
  2244. If this option is defined, the common CFI flash doesn't
  2245. print it's warning upon not recognized FLASH banks. This
  2246. is useful, if some of the configured banks are only
  2247. optionally available.
  2248. - CONFIG_FLASH_SHOW_PROGRESS
  2249. If defined (must be an integer), print out countdown
  2250. digits and dots. Recommended value: 45 (9..1) for 80
  2251. column displays, 15 (3..1) for 40 column displays.
  2252. - CONFIG_FLASH_VERIFY
  2253. If defined, the content of the flash (destination) is compared
  2254. against the source after the write operation. An error message
  2255. will be printed when the contents are not identical.
  2256. Please note that this option is useless in nearly all cases,
  2257. since such flash programming errors usually are detected earlier
  2258. while unprotecting/erasing/programming. Please only enable
  2259. this option if you really know what you are doing.
  2260. - CONFIG_SYS_RX_ETH_BUFFER:
  2261. Defines the number of Ethernet receive buffers. On some
  2262. Ethernet controllers it is recommended to set this value
  2263. to 8 or even higher (EEPRO100 or 405 EMAC), since all
  2264. buffers can be full shortly after enabling the interface
  2265. on high Ethernet traffic.
  2266. Defaults to 4 if not defined.
  2267. - CONFIG_ENV_MAX_ENTRIES
  2268. Maximum number of entries in the hash table that is used
  2269. internally to store the environment settings. The default
  2270. setting is supposed to be generous and should work in most
  2271. cases. This setting can be used to tune behaviour; see
  2272. lib/hashtable.c for details.
  2273. - CONFIG_ENV_FLAGS_LIST_DEFAULT
  2274. - CONFIG_ENV_FLAGS_LIST_STATIC
  2275. Enable validation of the values given to environment variables when
  2276. calling env set. Variables can be restricted to only decimal,
  2277. hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
  2278. the variables can also be restricted to IP address or MAC address.
  2279. The format of the list is:
  2280. type_attribute = [s|d|x|b|i|m]
  2281. access_attribute = [a|r|o|c]
  2282. attributes = type_attribute[access_attribute]
  2283. entry = variable_name[:attributes]
  2284. list = entry[,list]
  2285. The type attributes are:
  2286. s - String (default)
  2287. d - Decimal
  2288. x - Hexadecimal
  2289. b - Boolean ([1yYtT|0nNfF])
  2290. i - IP address
  2291. m - MAC address
  2292. The access attributes are:
  2293. a - Any (default)
  2294. r - Read-only
  2295. o - Write-once
  2296. c - Change-default
  2297. - CONFIG_ENV_FLAGS_LIST_DEFAULT
  2298. Define this to a list (string) to define the ".flags"
  2299. environment variable in the default or embedded environment.
  2300. - CONFIG_ENV_FLAGS_LIST_STATIC
  2301. Define this to a list (string) to define validation that
  2302. should be done if an entry is not found in the ".flags"
  2303. environment variable. To override a setting in the static
  2304. list, simply add an entry for the same variable name to the
  2305. ".flags" variable.
  2306. If CONFIG_REGEX is defined, the variable_name above is evaluated as a
  2307. regular expression. This allows multiple variables to define the same
  2308. flags without explicitly listing them for each variable.
  2309. - CONFIG_ENV_ACCESS_IGNORE_FORCE
  2310. If defined, don't allow the -f switch to env set override variable
  2311. access flags.
  2312. The following definitions that deal with the placement and management
  2313. of environment data (variable area); in general, we support the
  2314. following configurations:
  2315. - CONFIG_BUILD_ENVCRC:
  2316. Builds up envcrc with the target environment so that external utils
  2317. may easily extract it and embed it in final U-Boot images.
  2318. BE CAREFUL! The first access to the environment happens quite early
  2319. in U-Boot initialization (when we try to get the setting of for the
  2320. console baudrate). You *MUST* have mapped your NVRAM area then, or
  2321. U-Boot will hang.
  2322. Please note that even with NVRAM we still use a copy of the
  2323. environment in RAM: we could work on NVRAM directly, but we want to
  2324. keep settings there always unmodified except somebody uses "saveenv"
  2325. to save the current settings.
  2326. BE CAREFUL! For some special cases, the local device can not use
  2327. "saveenv" command. For example, the local device will get the
  2328. environment stored in a remote NOR flash by SRIO or PCIE link,
  2329. but it can not erase, write this NOR flash by SRIO or PCIE interface.
  2330. - CONFIG_NAND_ENV_DST
  2331. Defines address in RAM to which the nand_spl code should copy the
  2332. environment. If redundant environment is used, it will be copied to
  2333. CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
  2334. Please note that the environment is read-only until the monitor
  2335. has been relocated to RAM and a RAM copy of the environment has been
  2336. created; also, when using EEPROM you will have to use env_get_f()
  2337. until then to read environment variables.
  2338. The environment is protected by a CRC32 checksum. Before the monitor
  2339. is relocated into RAM, as a result of a bad CRC you will be working
  2340. with the compiled-in default environment - *silently*!!! [This is
  2341. necessary, because the first environment variable we need is the
  2342. "baudrate" setting for the console - if we have a bad CRC, we don't
  2343. have any device yet where we could complain.]
  2344. Note: once the monitor has been relocated, then it will complain if
  2345. the default environment is used; a new CRC is computed as soon as you
  2346. use the "saveenv" command to store a valid environment.
  2347. - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
  2348. Echo the inverted Ethernet link state to the fault LED.
  2349. Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
  2350. also needs to be defined.
  2351. - CONFIG_SYS_FAULT_MII_ADDR:
  2352. MII address of the PHY to check for the Ethernet link state.
  2353. - CONFIG_NS16550_MIN_FUNCTIONS:
  2354. Define this if you desire to only have use of the NS16550_init
  2355. and NS16550_putc functions for the serial driver located at
  2356. drivers/serial/ns16550.c. This option is useful for saving
  2357. space for already greatly restricted images, including but not
  2358. limited to NAND_SPL configurations.
  2359. - CONFIG_DISPLAY_BOARDINFO
  2360. Display information about the board that U-Boot is running on
  2361. when U-Boot starts up. The board function checkboard() is called
  2362. to do this.
  2363. - CONFIG_DISPLAY_BOARDINFO_LATE
  2364. Similar to the previous option, but display this information
  2365. later, once stdio is running and output goes to the LCD, if
  2366. present.
  2367. - CONFIG_BOARD_SIZE_LIMIT:
  2368. Maximum size of the U-Boot image. When defined, the
  2369. build system checks that the actual size does not
  2370. exceed it.
  2371. Low Level (hardware related) configuration options:
  2372. ---------------------------------------------------
  2373. - CONFIG_SYS_CACHELINE_SIZE:
  2374. Cache Line Size of the CPU.
  2375. - CONFIG_SYS_CCSRBAR_DEFAULT:
  2376. Default (power-on reset) physical address of CCSR on Freescale
  2377. PowerPC SOCs.
  2378. - CONFIG_SYS_CCSRBAR:
  2379. Virtual address of CCSR. On a 32-bit build, this is typically
  2380. the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
  2381. - CONFIG_SYS_CCSRBAR_PHYS:
  2382. Physical address of CCSR. CCSR can be relocated to a new
  2383. physical address, if desired. In this case, this macro should
  2384. be set to that address. Otherwise, it should be set to the
  2385. same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
  2386. is typically relocated on 36-bit builds. It is recommended
  2387. that this macro be defined via the _HIGH and _LOW macros:
  2388. #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
  2389. * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
  2390. - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
  2391. Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
  2392. either 0 (32-bit build) or 0xF (36-bit build). This macro is
  2393. used in assembly code, so it must not contain typecasts or
  2394. integer size suffixes (e.g. "ULL").
  2395. - CONFIG_SYS_CCSRBAR_PHYS_LOW:
  2396. Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
  2397. used in assembly code, so it must not contain typecasts or
  2398. integer size suffixes (e.g. "ULL").
  2399. - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
  2400. If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
  2401. forced to a value that ensures that CCSR is not relocated.
  2402. - Floppy Disk Support:
  2403. CONFIG_SYS_FDC_DRIVE_NUMBER
  2404. the default drive number (default value 0)
  2405. CONFIG_SYS_ISA_IO_STRIDE
  2406. defines the spacing between FDC chipset registers
  2407. (default value 1)
  2408. CONFIG_SYS_ISA_IO_OFFSET
  2409. defines the offset of register from address. It
  2410. depends on which part of the data bus is connected to
  2411. the FDC chipset. (default value 0)
  2412. If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
  2413. CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
  2414. default value.
  2415. if CONFIG_SYS_FDC_HW_INIT is defined, then the function
  2416. fdc_hw_init() is called at the beginning of the FDC
  2417. setup. fdc_hw_init() must be provided by the board
  2418. source code. It is used to make hardware-dependent
  2419. initializations.
  2420. - CONFIG_IDE_AHB:
  2421. Most IDE controllers were designed to be connected with PCI
  2422. interface. Only few of them were designed for AHB interface.
  2423. When software is doing ATA command and data transfer to
  2424. IDE devices through IDE-AHB controller, some additional
  2425. registers accessing to these kind of IDE-AHB controller
  2426. is required.
  2427. - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
  2428. DO NOT CHANGE unless you know exactly what you're
  2429. doing! (11-4) [MPC8xx systems only]
  2430. - CONFIG_SYS_INIT_RAM_ADDR:
  2431. Start address of memory area that can be used for
  2432. initial data and stack; please note that this must be
  2433. writable memory that is working WITHOUT special
  2434. initialization, i. e. you CANNOT use normal RAM which
  2435. will become available only after programming the
  2436. memory controller and running certain initialization
  2437. sequences.
  2438. U-Boot uses the following memory types:
  2439. - MPC8xx: IMMR (internal memory of the CPU)
  2440. - CONFIG_SYS_GBL_DATA_OFFSET:
  2441. Offset of the initial data structure in the memory
  2442. area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
  2443. CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
  2444. data is located at the end of the available space
  2445. (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
  2446. GENERATED_GBL_DATA_SIZE), and the initial stack is just
  2447. below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
  2448. CONFIG_SYS_GBL_DATA_OFFSET) downward.
  2449. Note:
  2450. On the MPC824X (or other systems that use the data
  2451. cache for initial memory) the address chosen for
  2452. CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
  2453. point to an otherwise UNUSED address space between
  2454. the top of RAM and the start of the PCI space.
  2455. - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
  2456. - CONFIG_SYS_OR_TIMING_SDRAM:
  2457. SDRAM timing
  2458. - CONFIG_SYS_MAMR_PTA:
  2459. periodic timer for refresh
  2460. - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
  2461. CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
  2462. CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
  2463. CONFIG_SYS_BR1_PRELIM:
  2464. Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
  2465. - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
  2466. CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
  2467. CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
  2468. Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
  2469. - CONFIG_PCI_ENUM_ONLY
  2470. Only scan through and get the devices on the buses.
  2471. Don't do any setup work, presumably because someone or
  2472. something has already done it, and we don't need to do it
  2473. a second time. Useful for platforms that are pre-booted
  2474. by coreboot or similar.
  2475. - CONFIG_PCI_INDIRECT_BRIDGE:
  2476. Enable support for indirect PCI bridges.
  2477. - CONFIG_SYS_SRIO:
  2478. Chip has SRIO or not
  2479. - CONFIG_SRIO1:
  2480. Board has SRIO 1 port available
  2481. - CONFIG_SRIO2:
  2482. Board has SRIO 2 port available
  2483. - CONFIG_SRIO_PCIE_BOOT_MASTER
  2484. Board can support master function for Boot from SRIO and PCIE
  2485. - CONFIG_SYS_SRIOn_MEM_VIRT:
  2486. Virtual Address of SRIO port 'n' memory region
  2487. - CONFIG_SYS_SRIOn_MEM_PHYS:
  2488. Physical Address of SRIO port 'n' memory region
  2489. - CONFIG_SYS_SRIOn_MEM_SIZE:
  2490. Size of SRIO port 'n' memory region
  2491. - CONFIG_SYS_NAND_BUSWIDTH_16BIT
  2492. Defined to tell the NAND controller that the NAND chip is using
  2493. a 16 bit bus.
  2494. Not all NAND drivers use this symbol.
  2495. Example of drivers that use it:
  2496. - drivers/mtd/nand/raw/ndfc.c
  2497. - drivers/mtd/nand/raw/mxc_nand.c
  2498. - CONFIG_SYS_NDFC_EBC0_CFG
  2499. Sets the EBC0_CFG register for the NDFC. If not defined
  2500. a default value will be used.
  2501. - CONFIG_SPD_EEPROM
  2502. Get DDR timing information from an I2C EEPROM. Common
  2503. with pluggable memory modules such as SODIMMs
  2504. SPD_EEPROM_ADDRESS
  2505. I2C address of the SPD EEPROM
  2506. - CONFIG_SYS_SPD_BUS_NUM
  2507. If SPD EEPROM is on an I2C bus other than the first
  2508. one, specify here. Note that the value must resolve
  2509. to something your driver can deal with.
  2510. - CONFIG_SYS_DDR_RAW_TIMING
  2511. Get DDR timing information from other than SPD. Common with
  2512. soldered DDR chips onboard without SPD. DDR raw timing
  2513. parameters are extracted from datasheet and hard-coded into
  2514. header files or board specific files.
  2515. - CONFIG_FSL_DDR_INTERACTIVE
  2516. Enable interactive DDR debugging. See doc/README.fsl-ddr.
  2517. - CONFIG_FSL_DDR_SYNC_REFRESH
  2518. Enable sync of refresh for multiple controllers.
  2519. - CONFIG_FSL_DDR_BIST
  2520. Enable built-in memory test for Freescale DDR controllers.
  2521. - CONFIG_SYS_83XX_DDR_USES_CS0
  2522. Only for 83xx systems. If specified, then DDR should
  2523. be configured using CS0 and CS1 instead of CS2 and CS3.
  2524. - CONFIG_RMII
  2525. Enable RMII mode for all FECs.
  2526. Note that this is a global option, we can't
  2527. have one FEC in standard MII mode and another in RMII mode.
  2528. - CONFIG_CRC32_VERIFY
  2529. Add a verify option to the crc32 command.
  2530. The syntax is:
  2531. => crc32 -v <address> <count> <crc32>
  2532. Where address/count indicate a memory area
  2533. and crc32 is the correct crc32 which the
  2534. area should have.
  2535. - CONFIG_LOOPW
  2536. Add the "loopw" memory command. This only takes effect if
  2537. the memory commands are activated globally (CONFIG_CMD_MEMORY).
  2538. - CONFIG_MX_CYCLIC
  2539. Add the "mdc" and "mwc" memory commands. These are cyclic
  2540. "md/mw" commands.
  2541. Examples:
  2542. => mdc.b 10 4 500
  2543. This command will print 4 bytes (10,11,12,13) each 500 ms.
  2544. => mwc.l 100 12345678 10
  2545. This command will write 12345678 to address 100 all 10 ms.
  2546. This only takes effect if the memory commands are activated
  2547. globally (CONFIG_CMD_MEMORY).
  2548. - CONFIG_SKIP_LOWLEVEL_INIT
  2549. [ARM, NDS32, MIPS, RISC-V only] If this variable is defined, then certain
  2550. low level initializations (like setting up the memory
  2551. controller) are omitted and/or U-Boot does not
  2552. relocate itself into RAM.
  2553. Normally this variable MUST NOT be defined. The only
  2554. exception is when U-Boot is loaded (to RAM) by some
  2555. other boot loader or by a debugger which performs
  2556. these initializations itself.
  2557. - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
  2558. [ARM926EJ-S only] This allows just the call to lowlevel_init()
  2559. to be skipped. The normal CP15 init (such as enabling the
  2560. instruction cache) is still performed.
  2561. - CONFIG_SPL_BUILD
  2562. Modifies the behaviour of start.S when compiling a loader
  2563. that is executed before the actual U-Boot. E.g. when
  2564. compiling a NAND SPL.
  2565. - CONFIG_TPL_BUILD
  2566. Modifies the behaviour of start.S when compiling a loader
  2567. that is executed after the SPL and before the actual U-Boot.
  2568. It is loaded by the SPL.
  2569. - CONFIG_SYS_MPC85XX_NO_RESETVEC
  2570. Only for 85xx systems. If this variable is specified, the section
  2571. .resetvec is not kept and the section .bootpg is placed in the
  2572. previous 4k of the .text section.
  2573. - CONFIG_ARCH_MAP_SYSMEM
  2574. Generally U-Boot (and in particular the md command) uses
  2575. effective address. It is therefore not necessary to regard
  2576. U-Boot address as virtual addresses that need to be translated
  2577. to physical addresses. However, sandbox requires this, since
  2578. it maintains its own little RAM buffer which contains all
  2579. addressable memory. This option causes some memory accesses
  2580. to be mapped through map_sysmem() / unmap_sysmem().
  2581. - CONFIG_X86_RESET_VECTOR
  2582. If defined, the x86 reset vector code is included. This is not
  2583. needed when U-Boot is running from Coreboot.
  2584. - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
  2585. Option to disable subpage write in NAND driver
  2586. driver that uses this:
  2587. drivers/mtd/nand/raw/davinci_nand.c
  2588. Freescale QE/FMAN Firmware Support:
  2589. -----------------------------------
  2590. The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
  2591. loading of "firmware", which is encoded in the QE firmware binary format.
  2592. This firmware often needs to be loaded during U-Boot booting, so macros
  2593. are used to identify the storage device (NOR flash, SPI, etc) and the address
  2594. within that device.
  2595. - CONFIG_SYS_FMAN_FW_ADDR
  2596. The address in the storage device where the FMAN microcode is located. The
  2597. meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
  2598. is also specified.
  2599. - CONFIG_SYS_QE_FW_ADDR
  2600. The address in the storage device where the QE microcode is located. The
  2601. meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
  2602. is also specified.
  2603. - CONFIG_SYS_QE_FMAN_FW_LENGTH
  2604. The maximum possible size of the firmware. The firmware binary format
  2605. has a field that specifies the actual size of the firmware, but it
  2606. might not be possible to read any part of the firmware unless some
  2607. local storage is allocated to hold the entire firmware first.
  2608. - CONFIG_SYS_QE_FMAN_FW_IN_NOR
  2609. Specifies that QE/FMAN firmware is located in NOR flash, mapped as
  2610. normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
  2611. virtual address in NOR flash.
  2612. - CONFIG_SYS_QE_FMAN_FW_IN_NAND
  2613. Specifies that QE/FMAN firmware is located in NAND flash.
  2614. CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
  2615. - CONFIG_SYS_QE_FMAN_FW_IN_MMC
  2616. Specifies that QE/FMAN firmware is located on the primary SD/MMC
  2617. device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
  2618. - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
  2619. Specifies that QE/FMAN firmware is located in the remote (master)
  2620. memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
  2621. can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
  2622. window->master inbound window->master LAW->the ucode address in
  2623. master's memory space.
  2624. Freescale Layerscape Management Complex Firmware Support:
  2625. ---------------------------------------------------------
  2626. The Freescale Layerscape Management Complex (MC) supports the loading of
  2627. "firmware".
  2628. This firmware often needs to be loaded during U-Boot booting, so macros
  2629. are used to identify the storage device (NOR flash, SPI, etc) and the address
  2630. within that device.
  2631. - CONFIG_FSL_MC_ENET
  2632. Enable the MC driver for Layerscape SoCs.
  2633. Freescale Layerscape Debug Server Support:
  2634. -------------------------------------------
  2635. The Freescale Layerscape Debug Server Support supports the loading of
  2636. "Debug Server firmware" and triggering SP boot-rom.
  2637. This firmware often needs to be loaded during U-Boot booting.
  2638. - CONFIG_SYS_MC_RSV_MEM_ALIGN
  2639. Define alignment of reserved memory MC requires
  2640. Reproducible builds
  2641. -------------------
  2642. In order to achieve reproducible builds, timestamps used in the U-Boot build
  2643. process have to be set to a fixed value.
  2644. This is done using the SOURCE_DATE_EPOCH environment variable.
  2645. SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
  2646. option for U-Boot or an environment variable in U-Boot.
  2647. SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
  2648. Building the Software:
  2649. ======================
  2650. Building U-Boot has been tested in several native build environments
  2651. and in many different cross environments. Of course we cannot support
  2652. all possibly existing versions of cross development tools in all
  2653. (potentially obsolete) versions. In case of tool chain problems we
  2654. recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
  2655. which is extensively used to build and test U-Boot.
  2656. If you are not using a native environment, it is assumed that you
  2657. have GNU cross compiling tools available in your path. In this case,
  2658. you must set the environment variable CROSS_COMPILE in your shell.
  2659. Note that no changes to the Makefile or any other source files are
  2660. necessary. For example using the ELDK on a 4xx CPU, please enter:
  2661. $ CROSS_COMPILE=ppc_4xx-
  2662. $ export CROSS_COMPILE
  2663. Note: If you wish to generate Windows versions of the utilities in
  2664. the tools directory you can use the MinGW toolchain
  2665. (http://www.mingw.org). Set your HOST tools to the MinGW
  2666. toolchain and execute 'make tools'. For example:
  2667. $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
  2668. Binaries such as tools/mkimage.exe will be created which can
  2669. be executed on computers running Windows.
  2670. U-Boot is intended to be simple to build. After installing the
  2671. sources you must configure U-Boot for one specific board type. This
  2672. is done by typing:
  2673. make NAME_defconfig
  2674. where "NAME_defconfig" is the name of one of the existing configu-
  2675. rations; see boards.cfg for supported names.
  2676. Note: for some board special configuration names may exist; check if
  2677. additional information is available from the board vendor; for
  2678. instance, the TQM823L systems are available without (standard)
  2679. or with LCD support. You can select such additional "features"
  2680. when choosing the configuration, i. e.
  2681. make TQM823L_defconfig
  2682. - will configure for a plain TQM823L, i. e. no LCD support
  2683. make TQM823L_LCD_defconfig
  2684. - will configure for a TQM823L with U-Boot console on LCD
  2685. etc.
  2686. Finally, type "make all", and you should get some working U-Boot
  2687. images ready for download to / installation on your system:
  2688. - "u-boot.bin" is a raw binary image
  2689. - "u-boot" is an image in ELF binary format
  2690. - "u-boot.srec" is in Motorola S-Record format
  2691. By default the build is performed locally and the objects are saved
  2692. in the source directory. One of the two methods can be used to change
  2693. this behavior and build U-Boot to some external directory:
  2694. 1. Add O= to the make command line invocations:
  2695. make O=/tmp/build distclean
  2696. make O=/tmp/build NAME_defconfig
  2697. make O=/tmp/build all
  2698. 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
  2699. export KBUILD_OUTPUT=/tmp/build
  2700. make distclean
  2701. make NAME_defconfig
  2702. make all
  2703. Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
  2704. variable.
  2705. User specific CPPFLAGS, AFLAGS and CFLAGS can be passed to the compiler by
  2706. setting the according environment variables KCPPFLAGS, KAFLAGS and KCFLAGS.
  2707. For example to treat all compiler warnings as errors:
  2708. make KCFLAGS=-Werror
  2709. Please be aware that the Makefiles assume you are using GNU make, so
  2710. for instance on NetBSD you might need to use "gmake" instead of
  2711. native "make".
  2712. If the system board that you have is not listed, then you will need
  2713. to port U-Boot to your hardware platform. To do this, follow these
  2714. steps:
  2715. 1. Create a new directory to hold your board specific code. Add any
  2716. files you need. In your board directory, you will need at least
  2717. the "Makefile" and a "<board>.c".
  2718. 2. Create a new configuration file "include/configs/<board>.h" for
  2719. your board.
  2720. 3. If you're porting U-Boot to a new CPU, then also create a new
  2721. directory to hold your CPU specific code. Add any files you need.
  2722. 4. Run "make <board>_defconfig" with your new name.
  2723. 5. Type "make", and you should get a working "u-boot.srec" file
  2724. to be installed on your target system.
  2725. 6. Debug and solve any problems that might arise.
  2726. [Of course, this last step is much harder than it sounds.]
  2727. Testing of U-Boot Modifications, Ports to New Hardware, etc.:
  2728. ==============================================================
  2729. If you have modified U-Boot sources (for instance added a new board
  2730. or support for new devices, a new CPU, etc.) you are expected to
  2731. provide feedback to the other developers. The feedback normally takes
  2732. the form of a "patch", i. e. a context diff against a certain (latest
  2733. official or latest in the git repository) version of U-Boot sources.
  2734. But before you submit such a patch, please verify that your modifi-
  2735. cation did not break existing code. At least make sure that *ALL* of
  2736. the supported boards compile WITHOUT ANY compiler warnings. To do so,
  2737. just run the buildman script (tools/buildman/buildman), which will
  2738. configure and build U-Boot for ALL supported system. Be warned, this
  2739. will take a while. Please see the buildman README, or run 'buildman -H'
  2740. for documentation.
  2741. See also "U-Boot Porting Guide" below.
  2742. Monitor Commands - Overview:
  2743. ============================
  2744. go - start application at address 'addr'
  2745. run - run commands in an environment variable
  2746. bootm - boot application image from memory
  2747. bootp - boot image via network using BootP/TFTP protocol
  2748. bootz - boot zImage from memory
  2749. tftpboot- boot image via network using TFTP protocol
  2750. and env variables "ipaddr" and "serverip"
  2751. (and eventually "gatewayip")
  2752. tftpput - upload a file via network using TFTP protocol
  2753. rarpboot- boot image via network using RARP/TFTP protocol
  2754. diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
  2755. loads - load S-Record file over serial line
  2756. loadb - load binary file over serial line (kermit mode)
  2757. md - memory display
  2758. mm - memory modify (auto-incrementing)
  2759. nm - memory modify (constant address)
  2760. mw - memory write (fill)
  2761. cp - memory copy
  2762. cmp - memory compare
  2763. crc32 - checksum calculation
  2764. i2c - I2C sub-system
  2765. sspi - SPI utility commands
  2766. base - print or set address offset
  2767. printenv- print environment variables
  2768. setenv - set environment variables
  2769. saveenv - save environment variables to persistent storage
  2770. protect - enable or disable FLASH write protection
  2771. erase - erase FLASH memory
  2772. flinfo - print FLASH memory information
  2773. nand - NAND memory operations (see doc/README.nand)
  2774. bdinfo - print Board Info structure
  2775. iminfo - print header information for application image
  2776. coninfo - print console devices and informations
  2777. ide - IDE sub-system
  2778. loop - infinite loop on address range
  2779. loopw - infinite write loop on address range
  2780. mtest - simple RAM test
  2781. icache - enable or disable instruction cache
  2782. dcache - enable or disable data cache
  2783. reset - Perform RESET of the CPU
  2784. echo - echo args to console
  2785. version - print monitor version
  2786. help - print online help
  2787. ? - alias for 'help'
  2788. Monitor Commands - Detailed Description:
  2789. ========================================
  2790. TODO.
  2791. For now: just type "help <command>".
  2792. Environment Variables:
  2793. ======================
  2794. U-Boot supports user configuration using Environment Variables which
  2795. can be made persistent by saving to Flash memory.
  2796. Environment Variables are set using "setenv", printed using
  2797. "printenv", and saved to Flash using "saveenv". Using "setenv"
  2798. without a value can be used to delete a variable from the
  2799. environment. As long as you don't save the environment you are
  2800. working with an in-memory copy. In case the Flash area containing the
  2801. environment is erased by accident, a default environment is provided.
  2802. Some configuration options can be set using Environment Variables.
  2803. List of environment variables (most likely not complete):
  2804. baudrate - see CONFIG_BAUDRATE
  2805. bootdelay - see CONFIG_BOOTDELAY
  2806. bootcmd - see CONFIG_BOOTCOMMAND
  2807. bootargs - Boot arguments when booting an RTOS image
  2808. bootfile - Name of the image to load with TFTP
  2809. bootm_low - Memory range available for image processing in the bootm
  2810. command can be restricted. This variable is given as
  2811. a hexadecimal number and defines lowest address allowed
  2812. for use by the bootm command. See also "bootm_size"
  2813. environment variable. Address defined by "bootm_low" is
  2814. also the base of the initial memory mapping for the Linux
  2815. kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
  2816. bootm_mapsize.
  2817. bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
  2818. This variable is given as a hexadecimal number and it
  2819. defines the size of the memory region starting at base
  2820. address bootm_low that is accessible by the Linux kernel
  2821. during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
  2822. as the default value if it is defined, and bootm_size is
  2823. used otherwise.
  2824. bootm_size - Memory range available for image processing in the bootm
  2825. command can be restricted. This variable is given as
  2826. a hexadecimal number and defines the size of the region
  2827. allowed for use by the bootm command. See also "bootm_low"
  2828. environment variable.
  2829. updatefile - Location of the software update file on a TFTP server, used
  2830. by the automatic software update feature. Please refer to
  2831. documentation in doc/README.update for more details.
  2832. autoload - if set to "no" (any string beginning with 'n'),
  2833. "bootp" will just load perform a lookup of the
  2834. configuration from the BOOTP server, but not try to
  2835. load any image using TFTP
  2836. autostart - if set to "yes", an image loaded using the "bootp",
  2837. "rarpboot", "tftpboot" or "diskboot" commands will
  2838. be automatically started (by internally calling
  2839. "bootm")
  2840. If set to "no", a standalone image passed to the
  2841. "bootm" command will be copied to the load address
  2842. (and eventually uncompressed), but NOT be started.
  2843. This can be used to load and uncompress arbitrary
  2844. data.
  2845. fdt_high - if set this restricts the maximum address that the
  2846. flattened device tree will be copied into upon boot.
  2847. For example, if you have a system with 1 GB memory
  2848. at physical address 0x10000000, while Linux kernel
  2849. only recognizes the first 704 MB as low memory, you
  2850. may need to set fdt_high as 0x3C000000 to have the
  2851. device tree blob be copied to the maximum address
  2852. of the 704 MB low memory, so that Linux kernel can
  2853. access it during the boot procedure.
  2854. If this is set to the special value 0xFFFFFFFF then
  2855. the fdt will not be copied at all on boot. For this
  2856. to work it must reside in writable memory, have
  2857. sufficient padding on the end of it for u-boot to
  2858. add the information it needs into it, and the memory
  2859. must be accessible by the kernel.
  2860. fdtcontroladdr- if set this is the address of the control flattened
  2861. device tree used by U-Boot when CONFIG_OF_CONTROL is
  2862. defined.
  2863. i2cfast - (PPC405GP|PPC405EP only)
  2864. if set to 'y' configures Linux I2C driver for fast
  2865. mode (400kHZ). This environment variable is used in
  2866. initialization code. So, for changes to be effective
  2867. it must be saved and board must be reset.
  2868. initrd_high - restrict positioning of initrd images:
  2869. If this variable is not set, initrd images will be
  2870. copied to the highest possible address in RAM; this
  2871. is usually what you want since it allows for
  2872. maximum initrd size. If for some reason you want to
  2873. make sure that the initrd image is loaded below the
  2874. CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
  2875. variable to a value of "no" or "off" or "0".
  2876. Alternatively, you can set it to a maximum upper
  2877. address to use (U-Boot will still check that it
  2878. does not overwrite the U-Boot stack and data).
  2879. For instance, when you have a system with 16 MB
  2880. RAM, and want to reserve 4 MB from use by Linux,
  2881. you can do this by adding "mem=12M" to the value of
  2882. the "bootargs" variable. However, now you must make
  2883. sure that the initrd image is placed in the first
  2884. 12 MB as well - this can be done with
  2885. setenv initrd_high 00c00000
  2886. If you set initrd_high to 0xFFFFFFFF, this is an
  2887. indication to U-Boot that all addresses are legal
  2888. for the Linux kernel, including addresses in flash
  2889. memory. In this case U-Boot will NOT COPY the
  2890. ramdisk at all. This may be useful to reduce the
  2891. boot time on your system, but requires that this
  2892. feature is supported by your Linux kernel.
  2893. ipaddr - IP address; needed for tftpboot command
  2894. loadaddr - Default load address for commands like "bootp",
  2895. "rarpboot", "tftpboot", "loadb" or "diskboot"
  2896. loads_echo - see CONFIG_LOADS_ECHO
  2897. serverip - TFTP server IP address; needed for tftpboot command
  2898. bootretry - see CONFIG_BOOT_RETRY_TIME
  2899. bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
  2900. bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
  2901. ethprime - controls which interface is used first.
  2902. ethact - controls which interface is currently active.
  2903. For example you can do the following
  2904. => setenv ethact FEC
  2905. => ping 192.168.0.1 # traffic sent on FEC
  2906. => setenv ethact SCC
  2907. => ping 10.0.0.1 # traffic sent on SCC
  2908. ethrotate - When set to "no" U-Boot does not go through all
  2909. available network interfaces.
  2910. It just stays at the currently selected interface.
  2911. netretry - When set to "no" each network operation will
  2912. either succeed or fail without retrying.
  2913. When set to "once" the network operation will
  2914. fail when all the available network interfaces
  2915. are tried once without success.
  2916. Useful on scripts which control the retry operation
  2917. themselves.
  2918. npe_ucode - set load address for the NPE microcode
  2919. silent_linux - If set then Linux will be told to boot silently, by
  2920. changing the console to be empty. If "yes" it will be
  2921. made silent. If "no" it will not be made silent. If
  2922. unset, then it will be made silent if the U-Boot console
  2923. is silent.
  2924. tftpsrcp - If this is set, the value is used for TFTP's
  2925. UDP source port.
  2926. tftpdstp - If this is set, the value is used for TFTP's UDP
  2927. destination port instead of the Well Know Port 69.
  2928. tftpblocksize - Block size to use for TFTP transfers; if not set,
  2929. we use the TFTP server's default block size
  2930. tftptimeout - Retransmission timeout for TFTP packets (in milli-
  2931. seconds, minimum value is 1000 = 1 second). Defines
  2932. when a packet is considered to be lost so it has to
  2933. be retransmitted. The default is 5000 = 5 seconds.
  2934. Lowering this value may make downloads succeed
  2935. faster in networks with high packet loss rates or
  2936. with unreliable TFTP servers.
  2937. tftptimeoutcountmax - maximum count of TFTP timeouts (no
  2938. unit, minimum value = 0). Defines how many timeouts
  2939. can happen during a single file transfer before that
  2940. transfer is aborted. The default is 10, and 0 means
  2941. 'no timeouts allowed'. Increasing this value may help
  2942. downloads succeed with high packet loss rates, or with
  2943. unreliable TFTP servers or client hardware.
  2944. vlan - When set to a value < 4095 the traffic over
  2945. Ethernet is encapsulated/received over 802.1q
  2946. VLAN tagged frames.
  2947. bootpretryperiod - Period during which BOOTP/DHCP sends retries.
  2948. Unsigned value, in milliseconds. If not set, the period will
  2949. be either the default (28000), or a value based on
  2950. CONFIG_NET_RETRY_COUNT, if defined. This value has
  2951. precedence over the valu based on CONFIG_NET_RETRY_COUNT.
  2952. The following image location variables contain the location of images
  2953. used in booting. The "Image" column gives the role of the image and is
  2954. not an environment variable name. The other columns are environment
  2955. variable names. "File Name" gives the name of the file on a TFTP
  2956. server, "RAM Address" gives the location in RAM the image will be
  2957. loaded to, and "Flash Location" gives the image's address in NOR
  2958. flash or offset in NAND flash.
  2959. *Note* - these variables don't have to be defined for all boards, some
  2960. boards currently use other variables for these purposes, and some
  2961. boards use these variables for other purposes.
  2962. Image File Name RAM Address Flash Location
  2963. ----- --------- ----------- --------------
  2964. u-boot u-boot u-boot_addr_r u-boot_addr
  2965. Linux kernel bootfile kernel_addr_r kernel_addr
  2966. device tree blob fdtfile fdt_addr_r fdt_addr
  2967. ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
  2968. The following environment variables may be used and automatically
  2969. updated by the network boot commands ("bootp" and "rarpboot"),
  2970. depending the information provided by your boot server:
  2971. bootfile - see above
  2972. dnsip - IP address of your Domain Name Server
  2973. dnsip2 - IP address of your secondary Domain Name Server
  2974. gatewayip - IP address of the Gateway (Router) to use
  2975. hostname - Target hostname
  2976. ipaddr - see above
  2977. netmask - Subnet Mask
  2978. rootpath - Pathname of the root filesystem on the NFS server
  2979. serverip - see above
  2980. There are two special Environment Variables:
  2981. serial# - contains hardware identification information such
  2982. as type string and/or serial number
  2983. ethaddr - Ethernet address
  2984. These variables can be set only once (usually during manufacturing of
  2985. the board). U-Boot refuses to delete or overwrite these variables
  2986. once they have been set once.
  2987. Further special Environment Variables:
  2988. ver - Contains the U-Boot version string as printed
  2989. with the "version" command. This variable is
  2990. readonly (see CONFIG_VERSION_VARIABLE).
  2991. Please note that changes to some configuration parameters may take
  2992. only effect after the next boot (yes, that's just like Windoze :-).
  2993. Callback functions for environment variables:
  2994. ---------------------------------------------
  2995. For some environment variables, the behavior of u-boot needs to change
  2996. when their values are changed. This functionality allows functions to
  2997. be associated with arbitrary variables. On creation, overwrite, or
  2998. deletion, the callback will provide the opportunity for some side
  2999. effect to happen or for the change to be rejected.
  3000. The callbacks are named and associated with a function using the
  3001. U_BOOT_ENV_CALLBACK macro in your board or driver code.
  3002. These callbacks are associated with variables in one of two ways. The
  3003. static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
  3004. in the board configuration to a string that defines a list of
  3005. associations. The list must be in the following format:
  3006. entry = variable_name[:callback_name]
  3007. list = entry[,list]
  3008. If the callback name is not specified, then the callback is deleted.
  3009. Spaces are also allowed anywhere in the list.
  3010. Callbacks can also be associated by defining the ".callbacks" variable
  3011. with the same list format above. Any association in ".callbacks" will
  3012. override any association in the static list. You can define
  3013. CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
  3014. ".callbacks" environment variable in the default or embedded environment.
  3015. If CONFIG_REGEX is defined, the variable_name above is evaluated as a
  3016. regular expression. This allows multiple variables to be connected to
  3017. the same callback without explicitly listing them all out.
  3018. The signature of the callback functions is:
  3019. int callback(const char *name, const char *value, enum env_op op, int flags)
  3020. * name - changed environment variable
  3021. * value - new value of the environment variable
  3022. * op - operation (create, overwrite, or delete)
  3023. * flags - attributes of the environment variable change, see flags H_* in
  3024. include/search.h
  3025. The return value is 0 if the variable change is accepted and 1 otherwise.
  3026. Command Line Parsing:
  3027. =====================
  3028. There are two different command line parsers available with U-Boot:
  3029. the old "simple" one, and the much more powerful "hush" shell:
  3030. Old, simple command line parser:
  3031. --------------------------------
  3032. - supports environment variables (through setenv / saveenv commands)
  3033. - several commands on one line, separated by ';'
  3034. - variable substitution using "... ${name} ..." syntax
  3035. - special characters ('$', ';') can be escaped by prefixing with '\',
  3036. for example:
  3037. setenv bootcmd bootm \${address}
  3038. - You can also escape text by enclosing in single apostrophes, for example:
  3039. setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
  3040. Hush shell:
  3041. -----------
  3042. - similar to Bourne shell, with control structures like
  3043. if...then...else...fi, for...do...done; while...do...done,
  3044. until...do...done, ...
  3045. - supports environment ("global") variables (through setenv / saveenv
  3046. commands) and local shell variables (through standard shell syntax
  3047. "name=value"); only environment variables can be used with "run"
  3048. command
  3049. General rules:
  3050. --------------
  3051. (1) If a command line (or an environment variable executed by a "run"
  3052. command) contains several commands separated by semicolon, and
  3053. one of these commands fails, then the remaining commands will be
  3054. executed anyway.
  3055. (2) If you execute several variables with one call to run (i. e.
  3056. calling run with a list of variables as arguments), any failing
  3057. command will cause "run" to terminate, i. e. the remaining
  3058. variables are not executed.
  3059. Note for Redundant Ethernet Interfaces:
  3060. =======================================
  3061. Some boards come with redundant Ethernet interfaces; U-Boot supports
  3062. such configurations and is capable of automatic selection of a
  3063. "working" interface when needed. MAC assignment works as follows:
  3064. Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
  3065. MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
  3066. "eth1addr" (=>eth1), "eth2addr", ...
  3067. If the network interface stores some valid MAC address (for instance
  3068. in SROM), this is used as default address if there is NO correspon-
  3069. ding setting in the environment; if the corresponding environment
  3070. variable is set, this overrides the settings in the card; that means:
  3071. o If the SROM has a valid MAC address, and there is no address in the
  3072. environment, the SROM's address is used.
  3073. o If there is no valid address in the SROM, and a definition in the
  3074. environment exists, then the value from the environment variable is
  3075. used.
  3076. o If both the SROM and the environment contain a MAC address, and
  3077. both addresses are the same, this MAC address is used.
  3078. o If both the SROM and the environment contain a MAC address, and the
  3079. addresses differ, the value from the environment is used and a
  3080. warning is printed.
  3081. o If neither SROM nor the environment contain a MAC address, an error
  3082. is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
  3083. a random, locally-assigned MAC is used.
  3084. If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
  3085. will be programmed into hardware as part of the initialization process. This
  3086. may be skipped by setting the appropriate 'ethmacskip' environment variable.
  3087. The naming convention is as follows:
  3088. "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
  3089. Image Formats:
  3090. ==============
  3091. U-Boot is capable of booting (and performing other auxiliary operations on)
  3092. images in two formats:
  3093. New uImage format (FIT)
  3094. -----------------------
  3095. Flexible and powerful format based on Flattened Image Tree -- FIT (similar
  3096. to Flattened Device Tree). It allows the use of images with multiple
  3097. components (several kernels, ramdisks, etc.), with contents protected by
  3098. SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
  3099. Old uImage format
  3100. -----------------
  3101. Old image format is based on binary files which can be basically anything,
  3102. preceded by a special header; see the definitions in include/image.h for
  3103. details; basically, the header defines the following image properties:
  3104. * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
  3105. 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
  3106. LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
  3107. Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
  3108. INTEGRITY).
  3109. * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
  3110. IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
  3111. Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC).
  3112. * Compression Type (uncompressed, gzip, bzip2)
  3113. * Load Address
  3114. * Entry Point
  3115. * Image Name
  3116. * Image Timestamp
  3117. The header is marked by a special Magic Number, and both the header
  3118. and the data portions of the image are secured against corruption by
  3119. CRC32 checksums.
  3120. Linux Support:
  3121. ==============
  3122. Although U-Boot should support any OS or standalone application
  3123. easily, the main focus has always been on Linux during the design of
  3124. U-Boot.
  3125. U-Boot includes many features that so far have been part of some
  3126. special "boot loader" code within the Linux kernel. Also, any
  3127. "initrd" images to be used are no longer part of one big Linux image;
  3128. instead, kernel and "initrd" are separate images. This implementation
  3129. serves several purposes:
  3130. - the same features can be used for other OS or standalone
  3131. applications (for instance: using compressed images to reduce the
  3132. Flash memory footprint)
  3133. - it becomes much easier to port new Linux kernel versions because
  3134. lots of low-level, hardware dependent stuff are done by U-Boot
  3135. - the same Linux kernel image can now be used with different "initrd"
  3136. images; of course this also means that different kernel images can
  3137. be run with the same "initrd". This makes testing easier (you don't
  3138. have to build a new "zImage.initrd" Linux image when you just
  3139. change a file in your "initrd"). Also, a field-upgrade of the
  3140. software is easier now.
  3141. Linux HOWTO:
  3142. ============
  3143. Porting Linux to U-Boot based systems:
  3144. ---------------------------------------
  3145. U-Boot cannot save you from doing all the necessary modifications to
  3146. configure the Linux device drivers for use with your target hardware
  3147. (no, we don't intend to provide a full virtual machine interface to
  3148. Linux :-).
  3149. But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
  3150. Just make sure your machine specific header file (for instance
  3151. include/asm-ppc/tqm8xx.h) includes the same definition of the Board
  3152. Information structure as we define in include/asm-<arch>/u-boot.h,
  3153. and make sure that your definition of IMAP_ADDR uses the same value
  3154. as your U-Boot configuration in CONFIG_SYS_IMMR.
  3155. Note that U-Boot now has a driver model, a unified model for drivers.
  3156. If you are adding a new driver, plumb it into driver model. If there
  3157. is no uclass available, you are encouraged to create one. See
  3158. doc/driver-model.
  3159. Configuring the Linux kernel:
  3160. -----------------------------
  3161. No specific requirements for U-Boot. Make sure you have some root
  3162. device (initial ramdisk, NFS) for your target system.
  3163. Building a Linux Image:
  3164. -----------------------
  3165. With U-Boot, "normal" build targets like "zImage" or "bzImage" are
  3166. not used. If you use recent kernel source, a new build target
  3167. "uImage" will exist which automatically builds an image usable by
  3168. U-Boot. Most older kernels also have support for a "pImage" target,
  3169. which was introduced for our predecessor project PPCBoot and uses a
  3170. 100% compatible format.
  3171. Example:
  3172. make TQM850L_defconfig
  3173. make oldconfig
  3174. make dep
  3175. make uImage
  3176. The "uImage" build target uses a special tool (in 'tools/mkimage') to
  3177. encapsulate a compressed Linux kernel image with header information,
  3178. CRC32 checksum etc. for use with U-Boot. This is what we are doing:
  3179. * build a standard "vmlinux" kernel image (in ELF binary format):
  3180. * convert the kernel into a raw binary image:
  3181. ${CROSS_COMPILE}-objcopy -O binary \
  3182. -R .note -R .comment \
  3183. -S vmlinux linux.bin
  3184. * compress the binary image:
  3185. gzip -9 linux.bin
  3186. * package compressed binary image for U-Boot:
  3187. mkimage -A ppc -O linux -T kernel -C gzip \
  3188. -a 0 -e 0 -n "Linux Kernel Image" \
  3189. -d linux.bin.gz uImage
  3190. The "mkimage" tool can also be used to create ramdisk images for use
  3191. with U-Boot, either separated from the Linux kernel image, or
  3192. combined into one file. "mkimage" encapsulates the images with a 64
  3193. byte header containing information about target architecture,
  3194. operating system, image type, compression method, entry points, time
  3195. stamp, CRC32 checksums, etc.
  3196. "mkimage" can be called in two ways: to verify existing images and
  3197. print the header information, or to build new images.
  3198. In the first form (with "-l" option) mkimage lists the information
  3199. contained in the header of an existing U-Boot image; this includes
  3200. checksum verification:
  3201. tools/mkimage -l image
  3202. -l ==> list image header information
  3203. The second form (with "-d" option) is used to build a U-Boot image
  3204. from a "data file" which is used as image payload:
  3205. tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
  3206. -n name -d data_file image
  3207. -A ==> set architecture to 'arch'
  3208. -O ==> set operating system to 'os'
  3209. -T ==> set image type to 'type'
  3210. -C ==> set compression type 'comp'
  3211. -a ==> set load address to 'addr' (hex)
  3212. -e ==> set entry point to 'ep' (hex)
  3213. -n ==> set image name to 'name'
  3214. -d ==> use image data from 'datafile'
  3215. Right now, all Linux kernels for PowerPC systems use the same load
  3216. address (0x00000000), but the entry point address depends on the
  3217. kernel version:
  3218. - 2.2.x kernels have the entry point at 0x0000000C,
  3219. - 2.3.x and later kernels have the entry point at 0x00000000.
  3220. So a typical call to build a U-Boot image would read:
  3221. -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
  3222. > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
  3223. > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
  3224. > examples/uImage.TQM850L
  3225. Image Name: 2.4.4 kernel for TQM850L
  3226. Created: Wed Jul 19 02:34:59 2000
  3227. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  3228. Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
  3229. Load Address: 0x00000000
  3230. Entry Point: 0x00000000
  3231. To verify the contents of the image (or check for corruption):
  3232. -> tools/mkimage -l examples/uImage.TQM850L
  3233. Image Name: 2.4.4 kernel for TQM850L
  3234. Created: Wed Jul 19 02:34:59 2000
  3235. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  3236. Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
  3237. Load Address: 0x00000000
  3238. Entry Point: 0x00000000
  3239. NOTE: for embedded systems where boot time is critical you can trade
  3240. speed for memory and install an UNCOMPRESSED image instead: this
  3241. needs more space in Flash, but boots much faster since it does not
  3242. need to be uncompressed:
  3243. -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
  3244. -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
  3245. > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
  3246. > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
  3247. > examples/uImage.TQM850L-uncompressed
  3248. Image Name: 2.4.4 kernel for TQM850L
  3249. Created: Wed Jul 19 02:34:59 2000
  3250. Image Type: PowerPC Linux Kernel Image (uncompressed)
  3251. Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
  3252. Load Address: 0x00000000
  3253. Entry Point: 0x00000000
  3254. Similar you can build U-Boot images from a 'ramdisk.image.gz' file
  3255. when your kernel is intended to use an initial ramdisk:
  3256. -> tools/mkimage -n 'Simple Ramdisk Image' \
  3257. > -A ppc -O linux -T ramdisk -C gzip \
  3258. > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
  3259. Image Name: Simple Ramdisk Image
  3260. Created: Wed Jan 12 14:01:50 2000
  3261. Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
  3262. Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
  3263. Load Address: 0x00000000
  3264. Entry Point: 0x00000000
  3265. The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
  3266. option performs the converse operation of the mkimage's second form (the "-d"
  3267. option). Given an image built by mkimage, the dumpimage extracts a "data file"
  3268. from the image:
  3269. tools/dumpimage -i image -T type -p position data_file
  3270. -i ==> extract from the 'image' a specific 'data_file'
  3271. -T ==> set image type to 'type'
  3272. -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
  3273. Installing a Linux Image:
  3274. -------------------------
  3275. To downloading a U-Boot image over the serial (console) interface,
  3276. you must convert the image to S-Record format:
  3277. objcopy -I binary -O srec examples/image examples/image.srec
  3278. The 'objcopy' does not understand the information in the U-Boot
  3279. image header, so the resulting S-Record file will be relative to
  3280. address 0x00000000. To load it to a given address, you need to
  3281. specify the target address as 'offset' parameter with the 'loads'
  3282. command.
  3283. Example: install the image to address 0x40100000 (which on the
  3284. TQM8xxL is in the first Flash bank):
  3285. => erase 40100000 401FFFFF
  3286. .......... done
  3287. Erased 8 sectors
  3288. => loads 40100000
  3289. ## Ready for S-Record download ...
  3290. ~>examples/image.srec
  3291. 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
  3292. ...
  3293. 15989 15990 15991 15992
  3294. [file transfer complete]
  3295. [connected]
  3296. ## Start Addr = 0x00000000
  3297. You can check the success of the download using the 'iminfo' command;
  3298. this includes a checksum verification so you can be sure no data
  3299. corruption happened:
  3300. => imi 40100000
  3301. ## Checking Image at 40100000 ...
  3302. Image Name: 2.2.13 for initrd on TQM850L
  3303. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  3304. Data Size: 335725 Bytes = 327 kB = 0 MB
  3305. Load Address: 00000000
  3306. Entry Point: 0000000c
  3307. Verifying Checksum ... OK
  3308. Boot Linux:
  3309. -----------
  3310. The "bootm" command is used to boot an application that is stored in
  3311. memory (RAM or Flash). In case of a Linux kernel image, the contents
  3312. of the "bootargs" environment variable is passed to the kernel as
  3313. parameters. You can check and modify this variable using the
  3314. "printenv" and "setenv" commands:
  3315. => printenv bootargs
  3316. bootargs=root=/dev/ram
  3317. => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
  3318. => printenv bootargs
  3319. bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
  3320. => bootm 40020000
  3321. ## Booting Linux kernel at 40020000 ...
  3322. Image Name: 2.2.13 for NFS on TQM850L
  3323. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  3324. Data Size: 381681 Bytes = 372 kB = 0 MB
  3325. Load Address: 00000000
  3326. Entry Point: 0000000c
  3327. Verifying Checksum ... OK
  3328. Uncompressing Kernel Image ... OK
  3329. Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
  3330. Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
  3331. time_init: decrementer frequency = 187500000/60
  3332. Calibrating delay loop... 49.77 BogoMIPS
  3333. Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
  3334. ...
  3335. If you want to boot a Linux kernel with initial RAM disk, you pass
  3336. the memory addresses of both the kernel and the initrd image (PPBCOOT
  3337. format!) to the "bootm" command:
  3338. => imi 40100000 40200000
  3339. ## Checking Image at 40100000 ...
  3340. Image Name: 2.2.13 for initrd on TQM850L
  3341. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  3342. Data Size: 335725 Bytes = 327 kB = 0 MB
  3343. Load Address: 00000000
  3344. Entry Point: 0000000c
  3345. Verifying Checksum ... OK
  3346. ## Checking Image at 40200000 ...
  3347. Image Name: Simple Ramdisk Image
  3348. Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
  3349. Data Size: 566530 Bytes = 553 kB = 0 MB
  3350. Load Address: 00000000
  3351. Entry Point: 00000000
  3352. Verifying Checksum ... OK
  3353. => bootm 40100000 40200000
  3354. ## Booting Linux kernel at 40100000 ...
  3355. Image Name: 2.2.13 for initrd on TQM850L
  3356. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  3357. Data Size: 335725 Bytes = 327 kB = 0 MB
  3358. Load Address: 00000000
  3359. Entry Point: 0000000c
  3360. Verifying Checksum ... OK
  3361. Uncompressing Kernel Image ... OK
  3362. ## Loading RAMDisk Image at 40200000 ...
  3363. Image Name: Simple Ramdisk Image
  3364. Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
  3365. Data Size: 566530 Bytes = 553 kB = 0 MB
  3366. Load Address: 00000000
  3367. Entry Point: 00000000
  3368. Verifying Checksum ... OK
  3369. Loading Ramdisk ... OK
  3370. Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
  3371. Boot arguments: root=/dev/ram
  3372. time_init: decrementer frequency = 187500000/60
  3373. Calibrating delay loop... 49.77 BogoMIPS
  3374. ...
  3375. RAMDISK: Compressed image found at block 0
  3376. VFS: Mounted root (ext2 filesystem).
  3377. bash#
  3378. Boot Linux and pass a flat device tree:
  3379. -----------
  3380. First, U-Boot must be compiled with the appropriate defines. See the section
  3381. titled "Linux Kernel Interface" above for a more in depth explanation. The
  3382. following is an example of how to start a kernel and pass an updated
  3383. flat device tree:
  3384. => print oftaddr
  3385. oftaddr=0x300000
  3386. => print oft
  3387. oft=oftrees/mpc8540ads.dtb
  3388. => tftp $oftaddr $oft
  3389. Speed: 1000, full duplex
  3390. Using TSEC0 device
  3391. TFTP from server 192.168.1.1; our IP address is 192.168.1.101
  3392. Filename 'oftrees/mpc8540ads.dtb'.
  3393. Load address: 0x300000
  3394. Loading: #
  3395. done
  3396. Bytes transferred = 4106 (100a hex)
  3397. => tftp $loadaddr $bootfile
  3398. Speed: 1000, full duplex
  3399. Using TSEC0 device
  3400. TFTP from server 192.168.1.1; our IP address is 192.168.1.2
  3401. Filename 'uImage'.
  3402. Load address: 0x200000
  3403. Loading:############
  3404. done
  3405. Bytes transferred = 1029407 (fb51f hex)
  3406. => print loadaddr
  3407. loadaddr=200000
  3408. => print oftaddr
  3409. oftaddr=0x300000
  3410. => bootm $loadaddr - $oftaddr
  3411. ## Booting image at 00200000 ...
  3412. Image Name: Linux-2.6.17-dirty
  3413. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  3414. Data Size: 1029343 Bytes = 1005.2 kB
  3415. Load Address: 00000000
  3416. Entry Point: 00000000
  3417. Verifying Checksum ... OK
  3418. Uncompressing Kernel Image ... OK
  3419. Booting using flat device tree at 0x300000
  3420. Using MPC85xx ADS machine description
  3421. Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
  3422. [snip]
  3423. More About U-Boot Image Types:
  3424. ------------------------------
  3425. U-Boot supports the following image types:
  3426. "Standalone Programs" are directly runnable in the environment
  3427. provided by U-Boot; it is expected that (if they behave
  3428. well) you can continue to work in U-Boot after return from
  3429. the Standalone Program.
  3430. "OS Kernel Images" are usually images of some Embedded OS which
  3431. will take over control completely. Usually these programs
  3432. will install their own set of exception handlers, device
  3433. drivers, set up the MMU, etc. - this means, that you cannot
  3434. expect to re-enter U-Boot except by resetting the CPU.
  3435. "RAMDisk Images" are more or less just data blocks, and their
  3436. parameters (address, size) are passed to an OS kernel that is
  3437. being started.
  3438. "Multi-File Images" contain several images, typically an OS
  3439. (Linux) kernel image and one or more data images like
  3440. RAMDisks. This construct is useful for instance when you want
  3441. to boot over the network using BOOTP etc., where the boot
  3442. server provides just a single image file, but you want to get
  3443. for instance an OS kernel and a RAMDisk image.
  3444. "Multi-File Images" start with a list of image sizes, each
  3445. image size (in bytes) specified by an "uint32_t" in network
  3446. byte order. This list is terminated by an "(uint32_t)0".
  3447. Immediately after the terminating 0 follow the images, one by
  3448. one, all aligned on "uint32_t" boundaries (size rounded up to
  3449. a multiple of 4 bytes).
  3450. "Firmware Images" are binary images containing firmware (like
  3451. U-Boot or FPGA images) which usually will be programmed to
  3452. flash memory.
  3453. "Script files" are command sequences that will be executed by
  3454. U-Boot's command interpreter; this feature is especially
  3455. useful when you configure U-Boot to use a real shell (hush)
  3456. as command interpreter.
  3457. Booting the Linux zImage:
  3458. -------------------------
  3459. On some platforms, it's possible to boot Linux zImage. This is done
  3460. using the "bootz" command. The syntax of "bootz" command is the same
  3461. as the syntax of "bootm" command.
  3462. Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
  3463. kernel with raw initrd images. The syntax is slightly different, the
  3464. address of the initrd must be augmented by it's size, in the following
  3465. format: "<initrd addres>:<initrd size>".
  3466. Standalone HOWTO:
  3467. =================
  3468. One of the features of U-Boot is that you can dynamically load and
  3469. run "standalone" applications, which can use some resources of
  3470. U-Boot like console I/O functions or interrupt services.
  3471. Two simple examples are included with the sources:
  3472. "Hello World" Demo:
  3473. -------------------
  3474. 'examples/hello_world.c' contains a small "Hello World" Demo
  3475. application; it is automatically compiled when you build U-Boot.
  3476. It's configured to run at address 0x00040004, so you can play with it
  3477. like that:
  3478. => loads
  3479. ## Ready for S-Record download ...
  3480. ~>examples/hello_world.srec
  3481. 1 2 3 4 5 6 7 8 9 10 11 ...
  3482. [file transfer complete]
  3483. [connected]
  3484. ## Start Addr = 0x00040004
  3485. => go 40004 Hello World! This is a test.
  3486. ## Starting application at 0x00040004 ...
  3487. Hello World
  3488. argc = 7
  3489. argv[0] = "40004"
  3490. argv[1] = "Hello"
  3491. argv[2] = "World!"
  3492. argv[3] = "This"
  3493. argv[4] = "is"
  3494. argv[5] = "a"
  3495. argv[6] = "test."
  3496. argv[7] = "<NULL>"
  3497. Hit any key to exit ...
  3498. ## Application terminated, rc = 0x0
  3499. Another example, which demonstrates how to register a CPM interrupt
  3500. handler with the U-Boot code, can be found in 'examples/timer.c'.
  3501. Here, a CPM timer is set up to generate an interrupt every second.
  3502. The interrupt service routine is trivial, just printing a '.'
  3503. character, but this is just a demo program. The application can be
  3504. controlled by the following keys:
  3505. ? - print current values og the CPM Timer registers
  3506. b - enable interrupts and start timer
  3507. e - stop timer and disable interrupts
  3508. q - quit application
  3509. => loads
  3510. ## Ready for S-Record download ...
  3511. ~>examples/timer.srec
  3512. 1 2 3 4 5 6 7 8 9 10 11 ...
  3513. [file transfer complete]
  3514. [connected]
  3515. ## Start Addr = 0x00040004
  3516. => go 40004
  3517. ## Starting application at 0x00040004 ...
  3518. TIMERS=0xfff00980
  3519. Using timer 1
  3520. tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
  3521. Hit 'b':
  3522. [q, b, e, ?] Set interval 1000000 us
  3523. Enabling timer
  3524. Hit '?':
  3525. [q, b, e, ?] ........
  3526. tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
  3527. Hit '?':
  3528. [q, b, e, ?] .
  3529. tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
  3530. Hit '?':
  3531. [q, b, e, ?] .
  3532. tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
  3533. Hit '?':
  3534. [q, b, e, ?] .
  3535. tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
  3536. Hit 'e':
  3537. [q, b, e, ?] ...Stopping timer
  3538. Hit 'q':
  3539. [q, b, e, ?] ## Application terminated, rc = 0x0
  3540. Minicom warning:
  3541. ================
  3542. Over time, many people have reported problems when trying to use the
  3543. "minicom" terminal emulation program for serial download. I (wd)
  3544. consider minicom to be broken, and recommend not to use it. Under
  3545. Unix, I recommend to use C-Kermit for general purpose use (and
  3546. especially for kermit binary protocol download ("loadb" command), and
  3547. use "cu" for S-Record download ("loads" command). See
  3548. http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
  3549. for help with kermit.
  3550. Nevertheless, if you absolutely want to use it try adding this
  3551. configuration to your "File transfer protocols" section:
  3552. Name Program Name U/D FullScr IO-Red. Multi
  3553. X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
  3554. Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
  3555. NetBSD Notes:
  3556. =============
  3557. Starting at version 0.9.2, U-Boot supports NetBSD both as host
  3558. (build U-Boot) and target system (boots NetBSD/mpc8xx).
  3559. Building requires a cross environment; it is known to work on
  3560. NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
  3561. need gmake since the Makefiles are not compatible with BSD make).
  3562. Note that the cross-powerpc package does not install include files;
  3563. attempting to build U-Boot will fail because <machine/ansi.h> is
  3564. missing. This file has to be installed and patched manually:
  3565. # cd /usr/pkg/cross/powerpc-netbsd/include
  3566. # mkdir powerpc
  3567. # ln -s powerpc machine
  3568. # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
  3569. # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
  3570. Native builds *don't* work due to incompatibilities between native
  3571. and U-Boot include files.
  3572. Booting assumes that (the first part of) the image booted is a
  3573. stage-2 loader which in turn loads and then invokes the kernel
  3574. proper. Loader sources will eventually appear in the NetBSD source
  3575. tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
  3576. meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
  3577. Implementation Internals:
  3578. =========================
  3579. The following is not intended to be a complete description of every
  3580. implementation detail. However, it should help to understand the
  3581. inner workings of U-Boot and make it easier to port it to custom
  3582. hardware.
  3583. Initial Stack, Global Data:
  3584. ---------------------------
  3585. The implementation of U-Boot is complicated by the fact that U-Boot
  3586. starts running out of ROM (flash memory), usually without access to
  3587. system RAM (because the memory controller is not initialized yet).
  3588. This means that we don't have writable Data or BSS segments, and BSS
  3589. is not initialized as zero. To be able to get a C environment working
  3590. at all, we have to allocate at least a minimal stack. Implementation
  3591. options for this are defined and restricted by the CPU used: Some CPU
  3592. models provide on-chip memory (like the IMMR area on MPC8xx and
  3593. MPC826x processors), on others (parts of) the data cache can be
  3594. locked as (mis-) used as memory, etc.
  3595. Chris Hallinan posted a good summary of these issues to the
  3596. U-Boot mailing list:
  3597. Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
  3598. From: "Chris Hallinan" <clh@net1plus.com>
  3599. Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
  3600. ...
  3601. Correct me if I'm wrong, folks, but the way I understand it
  3602. is this: Using DCACHE as initial RAM for Stack, etc, does not
  3603. require any physical RAM backing up the cache. The cleverness
  3604. is that the cache is being used as a temporary supply of
  3605. necessary storage before the SDRAM controller is setup. It's
  3606. beyond the scope of this list to explain the details, but you
  3607. can see how this works by studying the cache architecture and
  3608. operation in the architecture and processor-specific manuals.
  3609. OCM is On Chip Memory, which I believe the 405GP has 4K. It
  3610. is another option for the system designer to use as an
  3611. initial stack/RAM area prior to SDRAM being available. Either
  3612. option should work for you. Using CS 4 should be fine if your
  3613. board designers haven't used it for something that would
  3614. cause you grief during the initial boot! It is frequently not
  3615. used.
  3616. CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
  3617. with your processor/board/system design. The default value
  3618. you will find in any recent u-boot distribution in
  3619. walnut.h should work for you. I'd set it to a value larger
  3620. than your SDRAM module. If you have a 64MB SDRAM module, set
  3621. it above 400_0000. Just make sure your board has no resources
  3622. that are supposed to respond to that address! That code in
  3623. start.S has been around a while and should work as is when
  3624. you get the config right.
  3625. -Chris Hallinan
  3626. DS4.COM, Inc.
  3627. It is essential to remember this, since it has some impact on the C
  3628. code for the initialization procedures:
  3629. * Initialized global data (data segment) is read-only. Do not attempt
  3630. to write it.
  3631. * Do not use any uninitialized global data (or implicitly initialized
  3632. as zero data - BSS segment) at all - this is undefined, initiali-
  3633. zation is performed later (when relocating to RAM).
  3634. * Stack space is very limited. Avoid big data buffers or things like
  3635. that.
  3636. Having only the stack as writable memory limits means we cannot use
  3637. normal global data to share information between the code. But it
  3638. turned out that the implementation of U-Boot can be greatly
  3639. simplified by making a global data structure (gd_t) available to all
  3640. functions. We could pass a pointer to this data as argument to _all_
  3641. functions, but this would bloat the code. Instead we use a feature of
  3642. the GCC compiler (Global Register Variables) to share the data: we
  3643. place a pointer (gd) to the global data into a register which we
  3644. reserve for this purpose.
  3645. When choosing a register for such a purpose we are restricted by the
  3646. relevant (E)ABI specifications for the current architecture, and by
  3647. GCC's implementation.
  3648. For PowerPC, the following registers have specific use:
  3649. R1: stack pointer
  3650. R2: reserved for system use
  3651. R3-R4: parameter passing and return values
  3652. R5-R10: parameter passing
  3653. R13: small data area pointer
  3654. R30: GOT pointer
  3655. R31: frame pointer
  3656. (U-Boot also uses R12 as internal GOT pointer. r12
  3657. is a volatile register so r12 needs to be reset when
  3658. going back and forth between asm and C)
  3659. ==> U-Boot will use R2 to hold a pointer to the global data
  3660. Note: on PPC, we could use a static initializer (since the
  3661. address of the global data structure is known at compile time),
  3662. but it turned out that reserving a register results in somewhat
  3663. smaller code - although the code savings are not that big (on
  3664. average for all boards 752 bytes for the whole U-Boot image,
  3665. 624 text + 127 data).
  3666. On ARM, the following registers are used:
  3667. R0: function argument word/integer result
  3668. R1-R3: function argument word
  3669. R9: platform specific
  3670. R10: stack limit (used only if stack checking is enabled)
  3671. R11: argument (frame) pointer
  3672. R12: temporary workspace
  3673. R13: stack pointer
  3674. R14: link register
  3675. R15: program counter
  3676. ==> U-Boot will use R9 to hold a pointer to the global data
  3677. Note: on ARM, only R_ARM_RELATIVE relocations are supported.
  3678. On Nios II, the ABI is documented here:
  3679. http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
  3680. ==> U-Boot will use gp to hold a pointer to the global data
  3681. Note: on Nios II, we give "-G0" option to gcc and don't use gp
  3682. to access small data sections, so gp is free.
  3683. On NDS32, the following registers are used:
  3684. R0-R1: argument/return
  3685. R2-R5: argument
  3686. R15: temporary register for assembler
  3687. R16: trampoline register
  3688. R28: frame pointer (FP)
  3689. R29: global pointer (GP)
  3690. R30: link register (LP)
  3691. R31: stack pointer (SP)
  3692. PC: program counter (PC)
  3693. ==> U-Boot will use R10 to hold a pointer to the global data
  3694. NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
  3695. or current versions of GCC may "optimize" the code too much.
  3696. On RISC-V, the following registers are used:
  3697. x0: hard-wired zero (zero)
  3698. x1: return address (ra)
  3699. x2: stack pointer (sp)
  3700. x3: global pointer (gp)
  3701. x4: thread pointer (tp)
  3702. x5: link register (t0)
  3703. x8: frame pointer (fp)
  3704. x10-x11: arguments/return values (a0-1)
  3705. x12-x17: arguments (a2-7)
  3706. x28-31: temporaries (t3-6)
  3707. pc: program counter (pc)
  3708. ==> U-Boot will use gp to hold a pointer to the global data
  3709. Memory Management:
  3710. ------------------
  3711. U-Boot runs in system state and uses physical addresses, i.e. the
  3712. MMU is not used either for address mapping nor for memory protection.
  3713. The available memory is mapped to fixed addresses using the memory
  3714. controller. In this process, a contiguous block is formed for each
  3715. memory type (Flash, SDRAM, SRAM), even when it consists of several
  3716. physical memory banks.
  3717. U-Boot is installed in the first 128 kB of the first Flash bank (on
  3718. TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
  3719. booting and sizing and initializing DRAM, the code relocates itself
  3720. to the upper end of DRAM. Immediately below the U-Boot code some
  3721. memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
  3722. configuration setting]. Below that, a structure with global Board
  3723. Info data is placed, followed by the stack (growing downward).
  3724. Additionally, some exception handler code is copied to the low 8 kB
  3725. of DRAM (0x00000000 ... 0x00001FFF).
  3726. So a typical memory configuration with 16 MB of DRAM could look like
  3727. this:
  3728. 0x0000 0000 Exception Vector code
  3729. :
  3730. 0x0000 1FFF
  3731. 0x0000 2000 Free for Application Use
  3732. :
  3733. :
  3734. :
  3735. :
  3736. 0x00FB FF20 Monitor Stack (Growing downward)
  3737. 0x00FB FFAC Board Info Data and permanent copy of global data
  3738. 0x00FC 0000 Malloc Arena
  3739. :
  3740. 0x00FD FFFF
  3741. 0x00FE 0000 RAM Copy of Monitor Code
  3742. ... eventually: LCD or video framebuffer
  3743. ... eventually: pRAM (Protected RAM - unchanged by reset)
  3744. 0x00FF FFFF [End of RAM]
  3745. System Initialization:
  3746. ----------------------
  3747. In the reset configuration, U-Boot starts at the reset entry point
  3748. (on most PowerPC systems at address 0x00000100). Because of the reset
  3749. configuration for CS0# this is a mirror of the on board Flash memory.
  3750. To be able to re-map memory U-Boot then jumps to its link address.
  3751. To be able to implement the initialization code in C, a (small!)
  3752. initial stack is set up in the internal Dual Ported RAM (in case CPUs
  3753. which provide such a feature like), or in a locked part of the data
  3754. cache. After that, U-Boot initializes the CPU core, the caches and
  3755. the SIU.
  3756. Next, all (potentially) available memory banks are mapped using a
  3757. preliminary mapping. For example, we put them on 512 MB boundaries
  3758. (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
  3759. on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
  3760. programmed for SDRAM access. Using the temporary configuration, a
  3761. simple memory test is run that determines the size of the SDRAM
  3762. banks.
  3763. When there is more than one SDRAM bank, and the banks are of
  3764. different size, the largest is mapped first. For equal size, the first
  3765. bank (CS2#) is mapped first. The first mapping is always for address
  3766. 0x00000000, with any additional banks following immediately to create
  3767. contiguous memory starting from 0.
  3768. Then, the monitor installs itself at the upper end of the SDRAM area
  3769. and allocates memory for use by malloc() and for the global Board
  3770. Info data; also, the exception vector code is copied to the low RAM
  3771. pages, and the final stack is set up.
  3772. Only after this relocation will you have a "normal" C environment;
  3773. until that you are restricted in several ways, mostly because you are
  3774. running from ROM, and because the code will have to be relocated to a
  3775. new address in RAM.
  3776. U-Boot Porting Guide:
  3777. ----------------------
  3778. [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
  3779. list, October 2002]
  3780. int main(int argc, char *argv[])
  3781. {
  3782. sighandler_t no_more_time;
  3783. signal(SIGALRM, no_more_time);
  3784. alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
  3785. if (available_money > available_manpower) {
  3786. Pay consultant to port U-Boot;
  3787. return 0;
  3788. }
  3789. Download latest U-Boot source;
  3790. Subscribe to u-boot mailing list;
  3791. if (clueless)
  3792. email("Hi, I am new to U-Boot, how do I get started?");
  3793. while (learning) {
  3794. Read the README file in the top level directory;
  3795. Read http://www.denx.de/twiki/bin/view/DULG/Manual;
  3796. Read applicable doc/*.README;
  3797. Read the source, Luke;
  3798. /* find . -name "*.[chS]" | xargs grep -i <keyword> */
  3799. }
  3800. if (available_money > toLocalCurrency ($2500))
  3801. Buy a BDI3000;
  3802. else
  3803. Add a lot of aggravation and time;
  3804. if (a similar board exists) { /* hopefully... */
  3805. cp -a board/<similar> board/<myboard>
  3806. cp include/configs/<similar>.h include/configs/<myboard>.h
  3807. } else {
  3808. Create your own board support subdirectory;
  3809. Create your own board include/configs/<myboard>.h file;
  3810. }
  3811. Edit new board/<myboard> files
  3812. Edit new include/configs/<myboard>.h
  3813. while (!accepted) {
  3814. while (!running) {
  3815. do {
  3816. Add / modify source code;
  3817. } until (compiles);
  3818. Debug;
  3819. if (clueless)
  3820. email("Hi, I am having problems...");
  3821. }
  3822. Send patch file to the U-Boot email list;
  3823. if (reasonable critiques)
  3824. Incorporate improvements from email list code review;
  3825. else
  3826. Defend code as written;
  3827. }
  3828. return 0;
  3829. }
  3830. void no_more_time (int sig)
  3831. {
  3832. hire_a_guru();
  3833. }
  3834. Coding Standards:
  3835. -----------------
  3836. All contributions to U-Boot should conform to the Linux kernel
  3837. coding style; see the kernel coding style guide at
  3838. https://www.kernel.org/doc/html/latest/process/coding-style.html, and the
  3839. script "scripts/Lindent" in your Linux kernel source directory.
  3840. Source files originating from a different project (for example the
  3841. MTD subsystem) are generally exempt from these guidelines and are not
  3842. reformatted to ease subsequent migration to newer versions of those
  3843. sources.
  3844. Please note that U-Boot is implemented in C (and to some small parts in
  3845. Assembler); no C++ is used, so please do not use C++ style comments (//)
  3846. in your code.
  3847. Please also stick to the following formatting rules:
  3848. - remove any trailing white space
  3849. - use TAB characters for indentation and vertical alignment, not spaces
  3850. - make sure NOT to use DOS '\r\n' line feeds
  3851. - do not add more than 2 consecutive empty lines to source files
  3852. - do not add trailing empty lines to source files
  3853. Submissions which do not conform to the standards may be returned
  3854. with a request to reformat the changes.
  3855. Submitting Patches:
  3856. -------------------
  3857. Since the number of patches for U-Boot is growing, we need to
  3858. establish some rules. Submissions which do not conform to these rules
  3859. may be rejected, even when they contain important and valuable stuff.
  3860. Please see http://www.denx.de/wiki/U-Boot/Patches for details.
  3861. Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
  3862. see https://lists.denx.de/listinfo/u-boot
  3863. When you send a patch, please include the following information with
  3864. it:
  3865. * For bug fixes: a description of the bug and how your patch fixes
  3866. this bug. Please try to include a way of demonstrating that the
  3867. patch actually fixes something.
  3868. * For new features: a description of the feature and your
  3869. implementation.
  3870. * A CHANGELOG entry as plaintext (separate from the patch)
  3871. * For major contributions, add a MAINTAINERS file with your
  3872. information and associated file and directory references.
  3873. * When you add support for a new board, don't forget to add a
  3874. maintainer e-mail address to the boards.cfg file, too.
  3875. * If your patch adds new configuration options, don't forget to
  3876. document these in the README file.
  3877. * The patch itself. If you are using git (which is *strongly*
  3878. recommended) you can easily generate the patch using the
  3879. "git format-patch". If you then use "git send-email" to send it to
  3880. the U-Boot mailing list, you will avoid most of the common problems
  3881. with some other mail clients.
  3882. If you cannot use git, use "diff -purN OLD NEW". If your version of
  3883. diff does not support these options, then get the latest version of
  3884. GNU diff.
  3885. The current directory when running this command shall be the parent
  3886. directory of the U-Boot source tree (i. e. please make sure that
  3887. your patch includes sufficient directory information for the
  3888. affected files).
  3889. We prefer patches as plain text. MIME attachments are discouraged,
  3890. and compressed attachments must not be used.
  3891. * If one logical set of modifications affects or creates several
  3892. files, all these changes shall be submitted in a SINGLE patch file.
  3893. * Changesets that contain different, unrelated modifications shall be
  3894. submitted as SEPARATE patches, one patch per changeset.
  3895. Notes:
  3896. * Before sending the patch, run the buildman script on your patched
  3897. source tree and make sure that no errors or warnings are reported
  3898. for any of the boards.
  3899. * Keep your modifications to the necessary minimum: A patch
  3900. containing several unrelated changes or arbitrary reformats will be
  3901. returned with a request to re-formatting / split it.
  3902. * If you modify existing code, make sure that your new code does not
  3903. add to the memory footprint of the code ;-) Small is beautiful!
  3904. When adding new features, these should compile conditionally only
  3905. (using #ifdef), and the resulting code with the new feature
  3906. disabled must not need more memory than the old code without your
  3907. modification.
  3908. * Remember that there is a size limit of 100 kB per message on the
  3909. u-boot mailing list. Bigger patches will be moderated. If they are
  3910. reasonable and not too big, they will be acknowledged. But patches
  3911. bigger than the size limit should be avoided.