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rockchip: back-to-bootrom: replace assembly-implementation with C-code

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The back-to-bootrom implementation for Rockchip has always relied on
the stack-pointer being valid on entry, so there was little reason to
have this as an assembly implementation.

This provides a new C-only implementation of save_boot_params and
back_to_bootrom (relying on setjmp/longjmp) and removes the older
assembly-only implementation.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Tested-by: Andy Yan <andy.yan@rock-chips.com>
This commit is contained in:
Philipp Tomsich 2017-10-10 16:21:14 +02:00
parent b4806d6f1f
commit ecfd71891a
4 changed files with 73 additions and 79 deletions
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27
arch/arm/include/asm/arch-rockchip/bootrom.h
View file

@ -1,5 +1,6 @@
/*
* (C) Copyright 2017 Heiko Stuebner <heiko@sntech.de>
* (C) Copyright 2017 Theobroma Systems Design und Consulting GmbH
*
* SPDX-License-Identifier: GPL-2.0
*/
@ -14,15 +15,27 @@
extern u32 SAVE_SP_ADDR;
/**
* Hand control back to the bootrom to load another
* boot stage.
* back_to_bootrom() - return to bootrom (for TPL/SPL), passing a
* result code
*
* Transfer control back to the Rockchip BROM, restoring necessary
* register context and passing a command/result code to the BROM
* to instruct its next actions (e.g. continue boot sequence, enter
* download mode, ...).
*
* This function does not return.
*/
void back_to_bootrom(void);
enum rockchip_bootrom_cmd {
/*
* These can not start at 0, as 0 has a special meaning
* for setjmp().
*/
/**
* Assembler component for the above (do not call this directly)
*/
void _back_to_bootrom_s(void);
BROM_BOOT_NEXTSTAGE = 1, /* continue boot-sequence */
BROM_BOOT_ENTER_DNL, /* have BROM enter download-mode */
};
void back_to_bootrom(void);
/**
* Boot-device identifiers as used by the BROM

4
arch/arm/mach-rockchip/Makefile
View file

@ -8,8 +8,8 @@
# this may have entered from ATF with the stack-pointer pointing to
# inaccessible/protected memory (and the bootrom-helper assumes that
# the stack-pointer is valid before switching to the U-Boot stack).
obj-spl-$(CONFIG_ROCKCHIP_BROM_HELPER) += bootrom.o save_boot_param.o
obj-tpl-$(CONFIG_ROCKCHIP_BROM_HELPER) += bootrom.o save_boot_param.o
obj-spl-$(CONFIG_ROCKCHIP_BROM_HELPER) += bootrom.o
obj-tpl-$(CONFIG_ROCKCHIP_BROM_HELPER) += bootrom.o
obj-tpl-$(CONFIG_ROCKCHIP_RK3188) += rk3188-board-tpl.o
obj-tpl-$(CONFIG_ROCKCHIP_RK3288) += rk3288-board-tpl.o

52
arch/arm/mach-rockchip/bootrom.c
View file

@ -6,11 +6,61 @@
#include <common.h>
#include <asm/arch/bootrom.h>
#include <asm/setjmp.h>
#include <asm/system.h>
/*
* Force the jmp_buf to the data-section, as .bss will not be valid
* when save_boot_params is invoked.
*/
static jmp_buf brom_ctx __section(".data");
void back_to_bootrom(void)
{
#if CONFIG_IS_ENABLED(LIBCOMMON_SUPPORT)
puts("Returning to boot ROM...\n");
#endif
_back_to_bootrom_s();
longjmp(brom_ctx, BROM_BOOT_NEXTSTAGE);
}
/*
* All Rockchip BROM implementations enter with a valid stack-pointer,
* so this can safely be implemented in C (providing a single
* implementation both for ARMv7 and AArch64).
*/
int save_boot_params(void)
{
int ret = setjmp(brom_ctx);
switch (ret) {
case 0:
/*
* This is the initial pass through this function
* (i.e. saving the context), setjmp just setup up the
* brom_ctx: transfer back into the startup-code at
* 'save_boot_params_ret' and let the compiler know
* that this will not return.
*/
save_boot_params_ret();
while (true)
/* does not return */;
break;
case BROM_BOOT_NEXTSTAGE:
/*
* To instruct the BROM to boot the next stage, we
* need to return 0 to it: i.e. we need to rewrite
* the return code once more.
*/
ret = 0;
break;
default:
#if CONFIG_IS_ENABLED(LIBCOMMON_SUPPORT)
puts("FATAL: unexpected command to back_to_bootrom()\n");
#endif
hang();
};
return ret;
}

69
arch/arm/mach-rockchip/save_boot_param.S
View file

@ -1,69 +0,0 @@
/*
* (C) Copyright 2016 Rockchip Electronics Co., Ltd
* (C) Copyright 2017 Theobroma Systems Design und Consulting GmbH
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <linux/linkage.h>
#if defined(CONFIG_ARM64)
.globl SAVE_SP_ADDR
SAVE_SP_ADDR:
.quad 0
ENTRY(save_boot_params)
sub sp, sp, #0x60
stp x29, x30, [sp, #0x50]
stp x27, x28, [sp, #0x40]
stp x25, x26, [sp, #0x30]
stp x23, x24, [sp, #0x20]
stp x21, x22, [sp, #0x10]
stp x19, x20, [sp, #0]
ldr x8, =SAVE_SP_ADDR
mov x9, sp
str x9, [x8]
b save_boot_params_ret /* back to my caller */
ENDPROC(save_boot_params)
.globl _back_to_bootrom_s
ENTRY(_back_to_bootrom_s)
ldr x0, =SAVE_SP_ADDR
ldr x0, [x0]
mov sp, x0
ldp x29, x30, [sp, #0x50]
ldp x27, x28, [sp, #0x40]
ldp x25, x26, [sp, #0x30]
ldp x23, x24, [sp, #0x20]
ldp x21, x22, [sp, #0x10]
ldp x19, x20, [sp]
add sp, sp, #0x60
mov x0, xzr
ret
ENDPROC(_back_to_bootrom_s)
#else
.globl SAVE_SP_ADDR
SAVE_SP_ADDR:
.word 0
/*
* void save_boot_params
*
* Save sp, lr, r1~r12
*/
ENTRY(save_boot_params)
push {r1-r12, lr}
ldr r0, =SAVE_SP_ADDR
str sp, [r0]
b save_boot_params_ret @ back to my caller
ENDPROC(save_boot_params)
.globl _back_to_bootrom_s
ENTRY(_back_to_bootrom_s)
ldr r0, =SAVE_SP_ADDR
ldr sp, [r0]
mov r0, #0
pop {r1-r12, pc}
ENDPROC(_back_to_bootrom_s)
#endif