Signed-off-by: Marek Vasut <marek.vasut@gmail.com> Cc: Stefano Babic <sbabic@denx.de> Cc: Wolfgang Denk <wd@denx.de> Cc: Detlev Zundel <dzu@denx.de>master
Marek Vasut
14 years ago
committed by
Stefano Babic
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DENX M28EVK |
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=========== |
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This document describes the DENX M28/M28EVK U-Boot port. This document mostly |
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covers topics related to making the module/board bootable. |
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Terminology |
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----------- |
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The dollar symbol ($) introduces a snipped of shell code. This shall be typed |
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into the unix command prompt in U-Boot source code root directory. |
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The (=>) introduces a snipped of code that should by typed into U-Boot command |
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prompt. |
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Contents |
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-------- |
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0) Files of the M28/M28EVK port |
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1) Prerequisites |
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2) Compiling U-Boot for M28 |
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3) Installation of U-Boot for M28EVK to SD card |
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4) Installation of U-Boot for M28 to NAND flash |
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0) Files of the M28/M28EVK port |
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------------------------------- |
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arch/arm/cpu/arm926ejs/mx28/ - The CPU support code for the Freescale i.MX28 |
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arch/arm/include/asm/arch-mx28/ - Header files for the Freescale i.MX28 |
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board/denx/m28evk/ - M28EVK board specific files |
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include/configs/m28evk.h - M28EVK configuration file |
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1) Prerequisites |
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---------------- |
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To make the M28 module or the M28 module or M28EVK board bootable, some tools |
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are necessary. The first one is the "elftosb" tool distributed by Freescale |
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Semiconductor. The other tool is the "mxsboot" tool found in U-Boot source tree. |
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Firstly, obtain the elftosb archive from the following location: |
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http://foss.doredevelopment.dk/mirrors/imx/elftosb-10.12.01.tar.gz |
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We use a $VER variable here to denote the current version. At the time of |
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writing of this document, that is "10.12.01". To obtain the file from command |
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line, use: |
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$ VER="10.12.01" |
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$ wget http://foss.doredevelopment.dk/mirrors/imx/elftosb-${VER}.tar.gz |
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Extract the file: |
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$ tar xzf elftosb-${VER}.tar.gz |
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Compile the file. We need to manually tell the linker to use also libm: |
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$ cd elftosb-${VER}/ |
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$ make LIBS="-lstdc++ -lm" elftosb |
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Optionally, remove debugging symbols from elftosb: |
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$ strip bld/linux/elftosb |
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Finally, install the "elftosb" binary. The "install" target is missing, so just |
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copy the binary by hand: |
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$ sudo cp bld/linux/elftosb /usr/local/bin/ |
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Make sure the "elftosb" binary can be found in your $PATH, in this case this |
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means "/usr/local/bin/" has to be in your $PATH. |
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2) Compiling U-Boot for M28 |
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--------------------------- |
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Compiling the U-Boot for M28 is straightforward and done as compiling U-Boot |
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for any other ARM device. For cross-compiler setup, please refer to ELDK5.0 |
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documentation. First, clean up the source code: |
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$ make mrproper |
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Next, configure U-Boot for M28EVK: |
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$ make m28evk_config |
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Lastly, compile U-Boot and prepare a "BootStream". The "BootStream" is a special |
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type of file, which the i.MX28 CPU can boot. This is handled by the following |
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command: |
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$ make u-boot.sb |
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HINT: To speed-up the build process, you can add -j<N>, where N is number of |
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compiler instances that'll run in parallel. |
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The code produces "u-boot.sb" file. This file needs to be augmented with a |
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proper header to allow successful boot from SD or NAND. Adding the header is |
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discussed in the following chapters. |
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3) Installation of U-Boot for M28EVK to SD card |
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----------------------------------------------- |
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To boot an M28 from SD, set the boot mode DIP switches according to i.MX28 |
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manual chapter 12.2.1 (Table 12-2), PORT=SSP0, SD/MMC master on SSP0, 3.3V. |
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An SD card the i.MX28 CPU can use to boot U-Boot must contain a DOS partition |
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table, which in turn carries a partition of special type and which contains a |
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special header. The rest of partitions in the DOS partition table can be used |
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by the user. |
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To prepare such partition, use your favourite partitioning tool. The partition |
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must have the following parameters: |
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* Start sector .......... sector 2048 |
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* Partition size ........ at least 1024 kb |
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* Partition type ........ 0x53 (sometimes "OnTrack DM6 Aux3") |
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For example in Linux fdisk, the sequence for a clear card is the following: |
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* o ..................... create a clear partition table |
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* n ..................... create new partition |
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* p ............. primary partition |
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* 1 ............. first partition |
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* 2048 .......... first sector is 2048 |
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* +1M ........... make the partition 1Mb big |
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* t 1 ................... change first partition ID |
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* 53 ............ change the ID to 0x53 (OnTrack DM6 Aux3) |
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* <create other partitions> |
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* w ..................... write partition table to disk |
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The partition layout is ready, next the special partition must be filled with |
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proper contents. The contents is generated by running the following command (see |
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chapter 2)): |
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$ ./tools/mxsboot sd u-boot.sb u-boot.sd |
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The resulting file, "u-boot.sd", shall then be written to the partition. In this |
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case, we assume the first partition of the SD card is /dev/mmcblk0p1: |
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$ dd if=u-boot.sd of=/dev/mmcblk0p1 |
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Last step is to insert the card into M28EVK and boot. |
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NOTE: If the user needs to adjust the start sector, the "mxsboot" tool contains |
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a "-p" switch for that purpose. The "-p" switch takes the sector number as |
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an argument. |
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4) Installation of U-Boot for M28 to NAND flash |
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----------------------------------------------- |
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To boot an M28 from NAND, set the boot mode DIP switches according to i.MX28 |
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manual chapter 12.2.1 (Table 12-2), PORT=GPMI, NAND 1.8 V. |
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There are two possibilities when preparing an image writable to NAND flash. |
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I) The NAND wasn't written at all yet or the BCB is broken |
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---------------------------------------------------------- |
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In this case, both BCB (FCB and DBBT) and firmware needs to be |
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written to NAND. To generate NAND image containing all these, |
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there is a tool called "mxsboot" in the "tools/" directory. The tool |
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is invoked on "u-boot.sb" file from chapter 2): |
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$ ./tools/mxsboot nand u-boot.sb u-boot.nand |
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NOTE: The above invokation works for NAND flash with geometry of |
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2048b per page, 64b OOB data, 128kb erase size. If your chip |
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has a different geometry, please use: |
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-w <size> change page size (default 2048 b) |
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-o <size> change oob size (default 64 b) |
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-e <size> change erase size (default 131072 b) |
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The geometry information can be obtained from running U-Boot |
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on M28 by issuing the "nand info" command. |
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The resulting file, "u-boot.nand" can be written directly to NAND |
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from the U-Boot prompt. To simplify the process, the U-Boot default |
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environment contains script "update_nand_full" to update the system. |
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This script expects a working TFTP server containing the file |
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"u-boot.nand" in it's root directory. This can be changed by |
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adjusting the "update_nand_full_filename" varible. |
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To update the system, run the following in U-Boot prompt: |
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=> run update_nand_full |
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In case you would only need to update the bootloader in future, |
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see II) below. |
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II) The NAND was already written with a good BCB |
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------------------------------------------------ |
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This part applies after the part I) above was done at least once. |
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If part I) above was done correctly already, there is no need to |
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write the FCB and DBBT parts of NAND again. It's possible to upgrade |
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only the bootloader image. |
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To simplify the process of firmware update, the U-Boot default |
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environment contains script "update_nand_firmware" to update only |
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the firmware, without rewriting FCB and DBBT. |
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This script expects a working TFTP server containing the file |
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"u-boot.sb" in it's root directory. This can be changed by |
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adjusting the "update_nand_firmware_filename" varible. |
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To update the system, run the following in U-Boot prompt: |
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=> run update_nand_firmware |
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III) Special settings for the update scripts |
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-------------------------------------------- |
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There is a slight possibility of the user wanting to adjust the |
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STRIDE and COUNT options of the NAND boot. For description of these, |
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see i.MX28 manual section 12.12.1.2 and 12.12.1.3. |
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The update scripts take this possibility into account. In case the |
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user changes STRIDE by blowing fuses, the user also has to change |
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"update_nand_stride" variable. In case the user changes COUNT by |
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blowing fuses, the user also has to change "update_nand_count" |
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variable for the update scripts to work correctly. |
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In case the user needs to boot a firmware image bigger than 1Mb, the |
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user has to adjust the "update_nand_firmware_maxsz" variable for the |
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update scripts to work properly. |
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