u-boot/board/nokia/rx51/lowlevel_init.S
Pali Rohár 64d16706a0 Nokia RX-51: Fix calculating return address in save_boot_params
Commit e11c6c279d broke calculating lr register
in function save_boot_params() and caused U-Boot to crash at early boot time
on Nokia N900 board.

This patch fix calculating return address in lr register and make Nokia N900
board bootable again. Patch was tested in qemu and also on real N900 HW.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
2015-06-12 08:11:18 -04:00

191 lines
3.9 KiB
ArmAsm

/*
* (C) Copyright 2011-2012
* Pali Rohár <pali.rohar@gmail.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <config.h>
relocaddr: /* address of this relocaddr section after coping */
.word . /* address of section (calculated at compile time) */
startaddr: /* address of u-boot after copying */
.word CONFIG_SYS_TEXT_BASE
kernaddr: /* address of kernel after copying */
.word KERNEL_ADDRESS
kernsize: /* maximal size of kernel image */
.word KERNEL_MAXSIZE
kernoffs: /* offset of kernel image in loaded u-boot */
.word KERNEL_OFFSET
imagesize: /* maximal size of image */
.word IMAGE_MAXSIZE
ih_magic: /* IH_MAGIC in big endian from include/image.h */
.word 0x56190527
/*
* Routine: save_boot_params (called after reset from start.S)
* Description: Copy attached kernel to address KERNEL_ADDRESS
* Copy u-boot to address CONFIG_SYS_TEXT_BASE
* Return to copied u-boot address
*/
.global save_boot_params
save_boot_params:
/* Get return address */
ldr lr, =save_boot_params_ret
/* Copy valid attached kernel to address KERNEL_ADDRESS */
copy_kernel_start:
adr r0, relocaddr /* r0 - address of section relocaddr */
ldr r1, relocaddr /* r1 - address of relocaddr after relocation */
cmp r0, r1
/* r4 - calculated offset */
subhi r4, r0, r1
sublo r4, r1, r0
/* r0 - start of kernel before */
ldr r0, startaddr
addhi r0, r0, r4
sublo r0, r0, r4
ldr r1, kernoffs
add r0, r0, r1
/* r3 - start of kernel after */
ldr r3, kernaddr
/* r2 - end of kernel after */
ldr r1, kernsize
add r2, r3, r1
/* r1 - end of kernel before */
add r1, r0, r1
/* remove header in target kernel */
mov r5, #0
str r5, [r3]
/* check for valid kernel uImage */
ldr r4, [r0] /* r4 - 4 bytes header of kernel */
ldr r5, ih_magic /* r5 - IH_MAGIC */
cmp r4, r5
bne copy_kernel_end /* skip if invalid image */
copy_kernel_loop:
ldmdb r1!, {r3 - r10}
stmdb r2!, {r3 - r10}
cmp r1, r0
bhi copy_kernel_loop
copy_kernel_end:
mov r5, #0
str r5, [r0] /* remove 4 bytes header of kernel */
/* Fix u-boot code */
fix_start:
adr r0, relocaddr /* r0 - address of section relocaddr */
ldr r1, relocaddr /* r1 - address of relocaddr after relocation */
cmp r0, r1
beq copy_uboot_end /* skip if u-boot is on correct address */
/* r5 - calculated offset */
subhi r5, r0, r1
sublo r5, r1, r0
/* r6 - maximal u-boot size */
ldr r6, imagesize
/* r1 - start of u-boot after */
ldr r1, startaddr
/* r0 - start of u-boot before */
addhi r0, r1, r5
sublo r0, r1, r5
/* check if we need to move uboot copy code before calling it */
cmp r5, r6
bhi copy_uboot_start /* now coping u-boot code directly is safe */
copy_code_start:
/* r0 - start of u-boot before */
/* r1 - start of u-boot after */
/* r6 - maximal u-boot size */
/* r7 - maximal kernel size */
ldr r7, kernsize
/* r4 - end of kernel before */
add r4, r0, r6
add r4, r4, r7
/* r5 - end of u-boot after */
ldr r5, startaddr
add r5, r5, r6
/* r2 - start of loop code after */
cmp r4, r5 /* higher address (r4 or r5) */
movhs r2, r4
movlo r2, r5
/* r3 - end of loop code before */
adr r3, end
/* r4 - end of loop code after */
adr r4, copy_uboot_start
sub r4, r3, r4
add r4, r2, r4
copy_code_loop:
ldmdb r3!, {r7 - r10}
stmdb r4!, {r7 - r10}
cmp r4, r2
bhi copy_code_loop
copy_code_end:
mov pc, r2
/* Copy u-boot to address CONFIG_SYS_TEXT_BASE */
copy_uboot_start:
/* r0 - start of u-boot before */
/* r1 - start of u-boot after */
/* r6 - maximal u-boot size */
/* r2 - end of u-boot after */
add r2, r1, r6
/* condition for copying from left to right */
cmp r0, r1
addlo r1, r0, r6 /* r1 - end of u-boot before */
blo copy_uboot_loop_right
copy_uboot_loop_left:
ldmia r0!, {r3 - r10}
stmia r1!, {r3 - r10}
cmp r1, r2
blo copy_uboot_loop_left
b copy_uboot_end
copy_uboot_loop_right:
ldmdb r1!, {r3 - r10}
stmdb r2!, {r3 - r10}
cmp r1, r0
bhi copy_uboot_loop_right
copy_uboot_end:
bx lr
end: