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> 9 #include <asm/arch/boot_mode.h> 10 #include <asm/io.h> 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"); 19 20 static void _back_to_bootrom(enum rockchip_bootrom_cmd brom_cmd) 21 { 22 longjmp(brom_ctx, brom_cmd); 23 } 24 25 void back_to_bootrom(enum rockchip_bootrom_cmd brom_cmd) 26 { 27 #if CONFIG_IS_ENABLED(LIBCOMMON_SUPPORT) 28 puts("Returning to boot ROM...\n"); 29 #endif 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 * The bootrom never check this register, so we need 38 * to check it and back to bootrom at very early bootstage(before 39 * some basic configurations(such as interrupts) been 40 * changed by TPL/SPL, as the bootrom download operation 41 * relys on many default settings(such as interrupts) by 42 * it's self. 43 * Note: the boot mode register is configured by 44 * application(next stage bootloader, kernel, etc) via command or PC Tool, 45 * cleared by USB download(bootrom mode) or loader(other mode) after the 46 * tag has work. 47 */ 48 static bool check_back_to_brom_dnl_flag(void) 49 { 50 u32 boot_mode, boot_id; 51 52 if (CONFIG_ROCKCHIP_BOOT_MODE_REG && BROM_BOOTSOURCE_ID_ADDR) { 53 boot_mode = readl(CONFIG_ROCKCHIP_BOOT_MODE_REG); 54 boot_id = readl(BROM_BOOTSOURCE_ID_ADDR); 55 if (boot_id == BROM_BOOTSOURCE_USB) 56 writel(0, CONFIG_ROCKCHIP_BOOT_MODE_REG); 57 else if (boot_mode == BOOT_BROM_DOWNLOAD) 58 return true; 59 } 60 61 return false; 62 } 63 64 /* 65 * All Rockchip BROM implementations enter with a valid stack-pointer, 66 * so this can safely be implemented in C (providing a single 67 * implementation both for ARMv7 and AArch64). 68 */ 69 int save_boot_params(void) 70 { 71 int ret = setjmp(brom_ctx); 72 73 switch (ret) { 74 case 0: 75 if (check_back_to_brom_dnl_flag()) 76 _back_to_bootrom(BROM_BOOT_ENTER_DNL); 77 /* 78 * This is the initial pass through this function 79 * (i.e. saving the context), setjmp just setup up the 80 * brom_ctx: transfer back into the startup-code at 81 * 'save_boot_params_ret' and let the compiler know 82 * that this will not return. 83 */ 84 save_boot_params_ret(); 85 while (true) 86 /* does not return */; 87 break; 88 89 case BROM_BOOT_NEXTSTAGE: 90 /* 91 * To instruct the BROM to boot the next stage, we 92 * need to return 0 to it: i.e. we need to rewrite 93 * the return code once more. 94 */ 95 ret = 0; 96 break; 97 case BROM_BOOT_ENTER_DNL: 98 /* 99 * A non-zero return value will instruct the BROM enter 100 * download mode. 101 */ 102 ret = 1; 103 break; 104 default: 105 #if CONFIG_IS_ENABLED(LIBCOMMON_SUPPORT) 106 puts("FATAL: unexpected command to back_to_bootrom()\n"); 107 #endif 108 hang(); 109 }; 110 111 return ret; 112 } 113