[U-Boot] [PATCH] MIPS: start.S: make boot config at offset 0x10 configurable

[Daniel Schwierzeck]

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 at gmail.com>

---

 README                       |  5 -----
 arch/mips/Kconfig            | 22 ++++++++++++++++++++++
 arch/mips/cpu/start.S        | 21 +++++----------------
 scripts/config_whitelist.txt |  1 -
 4 files changed, 27 insertions(+), 22 deletions(-)

diff --git a/README b/README
index a91af2a189..0afb7779ed 100644
--- a/README
+++ b/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
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 6e5e0ffe65..94da431a85 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -390,6 +390,28 @@ 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
diff --git a/arch/mips/cpu/start.S b/arch/mips/cpu/start.S
index 6ca0916c06..1d21b2324a 100644
--- a/arch/mips/cpu/start.S
+++ b/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)
diff --git a/scripts/config_whitelist.txt b/scripts/config_whitelist.txt
index 1a5606d123..901ab7ca54 100644
--- a/scripts/config_whitelist.txt
+++ b/scripts/config_whitelist.txt
@@ -4433,7 +4433,6 @@ 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
-- 
2.18.0