u-boot/board/nokia/rx51/lowlevel_init.S
Pali Rohár 0ba6ce4b78 Nokia RX-51: Simplify calculation of attached kernel image address
Now when board starup code does not copy image to CONFIG_SYS_TEXT_BASE
address there is no need to calculate all addresses from base address at
runtime. The only address which needs to be calculated is attached kernel
image address which can be simplified at compile time without need to know
CONFIG_SYS_TEXT_BASE address or relocation address at the runtime.

Signed-off-by: Pali Rohár <pali@kernel.org>
2022-08-20 16:17:50 -04:00

96 lines
2.5 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0+ */
/*
* (C) Copyright 2011-2012
* Pali Rohár <pali@kernel.org>
*/
#include <config.h>
kernoffs: /* offset of kernel image from this address */
.word KERNEL_OFFSET - (. - CONFIG_SYS_TEXT_BASE)
kernaddr: /* address of kernel after copying */
.word KERNEL_ADDRESS
kernsize: /* maximal size of kernel image */
.word KERNEL_MAXSIZE
imagesize: /* maximal size of image */
.word IMAGE_MAXSIZE
ih_magic: /* IH_MAGIC in big endian from include/image.h */
.word 0x56190527
z_magic: /* LINUX_ARM_ZIMAGE_MAGIC */
.word 0x016f2818
/*
* Routine: save_boot_params (called after reset from start.S)
* Description: Copy attached kernel to address KERNEL_ADDRESS
*/
.global save_boot_params
save_boot_params:
/*
* Copy valid attached kernel to absolute address KERNEL_ADDRESS
*
* Nokia X-Loader is loading secondary image to address 0x80400000.
* NOLO is loading boot image to random place, so it doesn't really
* matter what is set in CONFIG_SYS_TEXT_BASE. We have to detect
* KERNEL_OFFSET from the current execution address and copy it to
* absolute address KERNEL_ADDRESS.
*
* Note that U-Boot has to be compiled with CONFIG_POSITION_INDEPENDENT
* because it is loaded at random address and not to the fixed address
* (CONFIG_SYS_TEXT_BASE).
*/
copy_kernel_start:
/* r0 - start of kernel before */
adr r0, kernoffs /* r0 - current address of kernoffs section */
ldr r1, kernoffs /* r1 - offset of kernel image from kernoffs section */
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] /* remove 4 bytes header of kernel uImage */
str r5, [r3, #36] /* remove 4 bytes header of kernel zImage */
/* check for valid kernel uImage */
ldr r4, [r0] /* r4 - 4 bytes header of kernel */
ldr r5, ih_magic /* r5 - IH_MAGIC */
cmp r4, r5
beq copy_kernel_loop
/* check for valid kernel zImage */
ldr r4, [r0, #36] /* r4 - 4 bytes header of kernel at offset 36 */
ldr r5, z_magic /* r5 - LINUX_ARM_ZIMAGE_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:
/* remove header in source kernel image */
mov r5, #0
str r5, [r0] /* remove 4 bytes header of kernel uImage */
str r5, [r0, #36] /* remove 4 bytes header of kernel zImage */
/* Returns */
b save_boot_params_ret