bootrom.c
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/**
* Copyright (c) 2017 Google, Inc
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <asm/arch/bootrom.h>
#include <asm/arch/boot_mode.h>
#include <asm/io.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");
static void _back_to_bootrom(enum rockchip_bootrom_cmd brom_cmd)
{
longjmp(brom_ctx, brom_cmd);
}
void back_to_bootrom(enum rockchip_bootrom_cmd brom_cmd)
{
#if CONFIG_IS_ENABLED(LIBCOMMON_SUPPORT)
puts("Returning to boot ROM...\n");
#endif
_back_to_bootrom(brom_cmd);
}
/*
* we back to bootrom download mode if get a
* BOOT_BROM_DOWNLOAD flag in boot mode register
*
* note: the boot mode register is configured by
* application(next stage bootloader, kernel, etc),
* and the bootrom never check this register, so we need
* to check it and back to bootrom at very early bootstage(before
* some basic configurations(such as interrupts) been
* changed by TPL/SPL, as the bootrom download operation
* relys on many default settings(such as interrupts) by
* it's self.
*/
static bool check_back_to_brom_dnl_flag(void)
{
u32 boot_mode;
if (CONFIG_ROCKCHIP_BOOT_MODE_REG) {
boot_mode = readl(CONFIG_ROCKCHIP_BOOT_MODE_REG);
if (boot_mode == BOOT_BROM_DOWNLOAD) {
writel(0, CONFIG_ROCKCHIP_BOOT_MODE_REG);
return true;
}
}
return false;
}
/*
* 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:
if (check_back_to_brom_dnl_flag())
_back_to_bootrom(BROM_BOOT_ENTER_DNL);
/*
* 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;
case BROM_BOOT_ENTER_DNL:
/*
* A non-zero return value will instruct the BROM enter
* download mode.
*/
ret = 1;
break;
default:
#if CONFIG_IS_ENABLED(LIBCOMMON_SUPPORT)
puts("FATAL: unexpected command to back_to_bootrom()\n");
#endif
hang();
};
return ret;
}