From 026a2078791b64aede220b1b1a3e4dfe4ab175e7 Mon Sep 17 00:00:00 2001 From: Michal Simek Date: Wed, 26 Jan 2011 13:41:05 +0100 Subject: [PATCH] microblaze: Fix DTB passing from bootloader Little endian system needs to check OF_DT_HEADER but it is swapped because it is in big-endian. Microblaze LE provides lwr instruction which loads magic number in BIG endian format which can be compared. There is used the fact that if you write 0x1 as word and load it as byte then you get for big-endian zero and 1 for little-endian. Signed-off-by: Michal Simek --- arch/microblaze/kernel/head.S | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/arch/microblaze/kernel/head.S b/arch/microblaze/kernel/head.S index 4243400..0db20b5 100644 --- a/arch/microblaze/kernel/head.S +++ b/arch/microblaze/kernel/head.S @@ -77,8 +77,18 @@ real_start: We ensure r7 points to a valid FDT, just in case the bootloader is broken or non-existent */ beqi r7, no_fdt_arg /* NULL pointer? don't copy */ - lw r11, r0, r7 /* Does r7 point to a */ - rsubi r11, r11, OF_DT_HEADER /* valid FDT? */ +/* Does r7 point to a valid FDT? Load HEADER magic number */ + /* Run time Big/Little endian platform */ + /* Save 1 as word and load byte - 0 - BIG, 1 - LITTLE */ + addik r11, r0, 0x1 /* BIG/LITTLE checking value */ + /* __bss_start will be zeroed later - it is just temp location */ + swi r11, r0, TOPHYS(__bss_start) + lbui r11, r0, TOPHYS(__bss_start) + beqid r11, big_endian /* DO NOT break delay stop dependency */ + lw r11, r0, r7 /* Big endian load in delay slot */ + lwr r11, r0, r7 /* Little endian load */ +big_endian: + rsubi r11, r11, OF_DT_HEADER /* Check FDT header */ beqi r11, _prepare_copy_fdt or r7, r0, r0 /* clear R7 when not valid DTB */ bnei r11, no_fdt_arg /* No - get out of here */ -- 2.7.4