/**
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* Copyright (c) 2017 Google, Inc
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <asm/arch/bootrom.h>
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#include <asm/arch/boot_mode.h>
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#include <asm/io.h>
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#include <asm/setjmp.h>
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#include <asm/system.h>
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/*
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* Force the jmp_buf to the data-section, as .bss will not be valid
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* when save_boot_params is invoked.
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*/
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static jmp_buf brom_ctx __section(".data");
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static void _back_to_bootrom(enum rockchip_bootrom_cmd brom_cmd)
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{
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longjmp(brom_ctx, brom_cmd);
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}
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void back_to_bootrom(enum rockchip_bootrom_cmd brom_cmd)
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{
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#if CONFIG_IS_ENABLED(LIBCOMMON_SUPPORT)
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puts("Returning to boot ROM...\n");
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#endif
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_back_to_bootrom(brom_cmd);
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}
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/*
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* We back to bootrom download mode if get a
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* BOOT_BROM_DOWNLOAD flag in boot mode register
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*
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* The bootrom never check this register, so we need
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* to check it and back to bootrom at very early bootstage(before
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* some basic configurations(such as interrupts) been
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* changed by TPL/SPL, as the bootrom download operation
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* relys on many default settings(such as interrupts) by
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* it's self.
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* Note: the boot mode register is configured by
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* application(next stage bootloader, kernel, etc) via command or PC Tool,
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* cleared by USB download(bootrom mode) or loader(other mode) after the
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* tag has work.
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*/
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static bool check_back_to_brom_dnl_flag(void)
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{
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u32 boot_mode, boot_id;
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if (CONFIG_ROCKCHIP_BOOT_MODE_REG && BROM_BOOTSOURCE_ID_ADDR) {
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boot_mode = readl(CONFIG_ROCKCHIP_BOOT_MODE_REG);
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boot_id = readl(BROM_BOOTSOURCE_ID_ADDR);
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if (boot_id == BROM_BOOTSOURCE_USB)
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writel(0, CONFIG_ROCKCHIP_BOOT_MODE_REG);
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else if (boot_mode == BOOT_BROM_DOWNLOAD)
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return true;
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}
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return false;
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}
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/*
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* All Rockchip BROM implementations enter with a valid stack-pointer,
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* so this can safely be implemented in C (providing a single
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* implementation both for ARMv7 and AArch64).
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*/
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int save_boot_params(void)
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{
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int ret = setjmp(brom_ctx);
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switch (ret) {
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case 0:
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if (check_back_to_brom_dnl_flag())
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_back_to_bootrom(BROM_BOOT_ENTER_DNL);
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/*
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* This is the initial pass through this function
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* (i.e. saving the context), setjmp just setup up the
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* brom_ctx: transfer back into the startup-code at
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* 'save_boot_params_ret' and let the compiler know
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* that this will not return.
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*/
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save_boot_params_ret();
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while (true)
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/* does not return */;
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break;
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case BROM_BOOT_NEXTSTAGE:
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/*
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* To instruct the BROM to boot the next stage, we
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* need to return 0 to it: i.e. we need to rewrite
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* the return code once more.
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*/
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ret = 0;
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break;
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case BROM_BOOT_ENTER_DNL:
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/*
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* A non-zero return value will instruct the BROM enter
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* download mode.
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*/
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ret = 1;
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break;
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default:
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#if CONFIG_IS_ENABLED(LIBCOMMON_SUPPORT)
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puts("FATAL: unexpected command to back_to_bootrom()\n");
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#endif
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hang();
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};
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return ret;
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}
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