MIPS: start.S: make boot config at offset 0x10 configurable

Some MIPS systems store some board-specific boot configuration
in the U-Boot binary at offset 0x10. This is used by Malta boards
and by Lantiq/Intel SoC's when booting from parallel NOR flash.

Convert the hard-coded values to Kconfig options to remove such
board-specific stuff out of the generic start.S code. This also
deprecates the config option CONFIG_SYS_XWAY_EBU_BOOTCFG.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>

README

@@ -542,11 +542,6 @@ The following options need to be configured:
 			CONF_CM_CACHABLE_CUW
 			CONF_CM_CACHABLE_ACCELERATED
 
-		CONFIG_SYS_XWAY_EBU_BOOTCFG
-
-		Special option for Lantiq XWAY SoCs for booting from NOR flash.
-		See also arch/mips/cpu/mips32/start.S.
-
 		CONFIG_XWAY_SWAP_BYTES
 
 		Enable compilation of tools/xway-swap-bytes needed for Lantiq

arch/mips/Kconfig

@@ -28,6 +28,7 @@ config TARGET_MALTA
 	select DM_SERIAL
 	select DYNAMIC_IO_PORT_BASE
 	select MIPS_CM
+	select MIPS_INSERT_BOOT_CONFIG
 	select MIPS_L1_CACHE_SHIFT_6
 	select MIPS_L2_CACHE
 	select OF_CONTROL
@@ -390,6 +391,28 @@ config MIPS_CM
 	  wish U-Boot to configure it or make use of it to retrieve system
 	  information such as cache configuration.
 
+config MIPS_INSERT_BOOT_CONFIG
+	bool
+	default n
+	help
+	  Enable this to insert some board-specific boot configuration in
+	  the U-Boot binary at offset 0x10.
+
+config MIPS_BOOT_CONFIG_WORD0
+	hex
+	depends on MIPS_INSERT_BOOT_CONFIG
+	default 0x420 if TARGET_MALTA
+	default 0x0
+	help
+	  Value which is inserted as boot config word 0.
+
+config MIPS_BOOT_CONFIG_WORD1
+	hex
+	depends on MIPS_INSERT_BOOT_CONFIG
+	default 0x0
+	help
+	  Value which is inserted as boot config word 1.
+
 endif
 
 endmenu

arch/mips/cpu/start.S

@@ -84,25 +84,14 @@ ENTRY(_start)
 	b	reset
 	 mtc0	zero, CP0_COUNT	# clear cp0 count for most accurate boot timing
 
-#if defined(CONFIG_SYS_XWAY_EBU_BOOTCFG)
+#if defined(CONFIG_MIPS_INSERT_BOOT_CONFIG)
 	/*
-	 * Almost all Lantiq XWAY SoC devices have an external bus unit (EBU) to
-	 * access external NOR flashes. If the board boots from NOR flash the
-	 * internal BootROM does a blind read at address 0xB0000010 to read the
-	 * initial configuration for that EBU in order to access the flash
-	 * device with correct parameters. This config option is board-specific.
+	 * Store some board-specific boot configuration. This is used by some
+	 * MIPS systems like Malta.
 	 */
 	.org 0x10
-	.word CONFIG_SYS_XWAY_EBU_BOOTCFG
-	.word 0x0
-#endif
-#if defined(CONFIG_MALTA)
-	/*
-	 * Linux expects the Board ID here.
-	 */
-	.org 0x10
-	.word 0x00000420	# 0x420 (Malta Board with CoreLV)
-	.word 0x00000000
+	.word CONFIG_MIPS_BOOT_CONFIG_WORD0
+	.word CONFIG_MIPS_BOOT_CONFIG_WORD1
 #endif
 
 #if defined(CONFIG_ROM_EXCEPTION_VECTORS)

scripts/config_whitelist.txt

@@ -4421,7 +4421,6 @@ CONFIG_SYS_XHCI_USB1_ADDR
 CONFIG_SYS_XHCI_USB2_ADDR
 CONFIG_SYS_XHCI_USB3_ADDR
 CONFIG_SYS_XIMG_LEN
-CONFIG_SYS_XWAY_EBU_BOOTCFG
 CONFIG_SYS_ZYNQ_QSPI_WAIT
 CONFIG_SYS_ZYNQ_SPI_WAIT
 CONFIG_SYS_i2C_FSL