[people/ms/u-boot.git] / arch / arm / mach-rockchip / bootrom.c

/**
 * 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;
}
Commit	Line	Data
e1bc64ee SG	1	/**
	2	* Copyright (c) 2017 Google, Inc
	3	*
	4	* SPDX-License-Identifier: GPL-2.0+
	5	*/
	6
	7	#include <common.h>
	8	#include <asm/arch/bootrom.h>
b4d23f76 AY	9	#include <asm/arch/boot_mode.h>
b4d23f76 AY	10	#include <asm/io.h>
ecfd7189 PT	11	#include <asm/setjmp.h>
	12	#include <asm/system.h>
	13
	14	/*
	15	* Force the jmp_buf to the data-section, as .bss will not be valid
	16	* when save_boot_params is invoked.
	17	*/
	18	static jmp_buf brom_ctx __section(".data");
e1bc64ee	19
b4d23f76 AY	20	static void _back_to_bootrom(enum rockchip_bootrom_cmd brom_cmd)
	21	{
	22	longjmp(brom_ctx, brom_cmd);
	23	}
	24
b82bd1f8	25	void back_to_bootrom(enum rockchip_bootrom_cmd brom_cmd)
e1bc64ee	26	{
19b68fb2 PT	27	#if CONFIG_IS_ENABLED(LIBCOMMON_SUPPORT)
19b68fb2 PT	28	puts("Returning to boot ROM...\n");
e1bc64ee	29	#endif
b4d23f76 AY	30	_back_to_bootrom(brom_cmd);
	31	}
	32
	33	/*
	34	* we back to bootrom download mode if get a
	35	* BOOT_BROM_DOWNLOAD flag in boot mode register
	36	*
	37	* note: the boot mode register is configured by
	38	* application(next stage bootloader, kernel, etc),
	39	* and the bootrom never check this register, so we need
	40	* to check it and back to bootrom at very early bootstage(before
	41	* some basic configurations(such as interrupts) been
	42	* changed by TPL/SPL, as the bootrom download operation
	43	* relys on many default settings(such as interrupts) by
	44	* it's self.
	45	*/
	46	static bool check_back_to_brom_dnl_flag(void)
	47	{
	48	u32 boot_mode;
	49
	50	if (CONFIG_ROCKCHIP_BOOT_MODE_REG) {
	51	boot_mode = readl(CONFIG_ROCKCHIP_BOOT_MODE_REG);
	52	if (boot_mode == BOOT_BROM_DOWNLOAD) {
	53	writel(0, CONFIG_ROCKCHIP_BOOT_MODE_REG);
	54	return true;
	55	}
	56	}
	57
	58	return false;
ecfd7189 PT	59	}
	60
	61	/*
	62	* All Rockchip BROM implementations enter with a valid stack-pointer,
	63	* so this can safely be implemented in C (providing a single
	64	* implementation both for ARMv7 and AArch64).
	65	*/
	66	int save_boot_params(void)
	67	{
	68	int ret = setjmp(brom_ctx);
	69
	70	switch (ret) {
	71	case 0:
b4d23f76 AY	72	if (check_back_to_brom_dnl_flag())
b4d23f76 AY	73	_back_to_bootrom(BROM_BOOT_ENTER_DNL);
ecfd7189 PT	74	/*
	75	* This is the initial pass through this function
	76	* (i.e. saving the context), setjmp just setup up the
	77	* brom_ctx: transfer back into the startup-code at
	78	* 'save_boot_params_ret' and let the compiler know
	79	* that this will not return.
	80	*/
	81	save_boot_params_ret();
	82	while (true)
	83	/* does not return */;
	84	break;
	85
	86	case BROM_BOOT_NEXTSTAGE:
	87	/*
	88	* To instruct the BROM to boot the next stage, we
	89	* need to return 0 to it: i.e. we need to rewrite
	90	* the return code once more.
	91	*/
	92	ret = 0;
	93	break;
b4d23f76 AY	94	case BROM_BOOT_ENTER_DNL:
	95	/*
	96	* A non-zero return value will instruct the BROM enter
	97	* download mode.
	98	*/
	99	ret = 1;
	100	break;
ecfd7189 PT	101	default:
	102	#if CONFIG_IS_ENABLED(LIBCOMMON_SUPPORT)
	103	puts("FATAL: unexpected command to back_to_bootrom()\n");
	104	#endif
	105	hang();
	106	};
	107
	108	return ret;
e1bc64ee	109	}