1 // SPDX-License-Identifier: GPL-2.0+
2 /**
3 * Copyright (c) 2017 Google, Inc
4 */
5
6 #include <common.h>
7 #include <hang.h>
8 #include <asm/arch-rockchip/bootrom.h>
9 #include <asm/arch-rockchip/boot_mode.h>
10 #include <asm/cache.h>
11 #include <asm/io.h>
12 #include <asm/setjmp.h>
13 #include <asm/system.h>
14
15 /*
16 * Force the jmp_buf to the data-section, as .bss will not be valid
17 * when save_boot_params is invoked.
18 */
19 static jmp_buf brom_ctx __section(".data");
20
_back_to_bootrom(enum rockchip_bootrom_cmd brom_cmd)21 static void _back_to_bootrom(enum rockchip_bootrom_cmd brom_cmd)
22 {
23 longjmp(brom_ctx, brom_cmd);
24 }
25
back_to_bootrom(enum rockchip_bootrom_cmd brom_cmd)26 void back_to_bootrom(enum rockchip_bootrom_cmd brom_cmd)
27 {
28 #if CONFIG_IS_ENABLED(LIBCOMMON_SUPPORT)
29 puts("Returning to boot ROM...\n");
30 #endif
31 _back_to_bootrom(brom_cmd);
32 }
33
34 /*
35 * we back to bootrom download mode if get a
36 * BOOT_BROM_DOWNLOAD flag in boot mode register
37 *
38 * note: the boot mode register is configured by
39 * application(next stage bootloader, kernel, etc),
40 * and the bootrom never check this register, so we need
41 * to check it and back to bootrom at very early bootstage(before
42 * some basic configurations(such as interrupts) been
43 * changed by TPL/SPL, as the bootrom download operation
44 * relies on many default settings(such as interrupts) by
45 * itself.
46 */
check_back_to_brom_dnl_flag(void)47 static bool check_back_to_brom_dnl_flag(void)
48 {
49 u32 boot_mode;
50
51 if (CONFIG_ROCKCHIP_BOOT_MODE_REG) {
52 boot_mode = readl(CONFIG_ROCKCHIP_BOOT_MODE_REG);
53 if (boot_mode == BOOT_BROM_DOWNLOAD) {
54 writel(0, CONFIG_ROCKCHIP_BOOT_MODE_REG);
55 return true;
56 }
57 }
58
59 return false;
60 }
61
62 /*
63 * All Rockchip BROM implementations enter with a valid stack-pointer,
64 * so this can safely be implemented in C (providing a single
65 * implementation both for ARMv7 and AArch64).
66 */
save_boot_params(void)67 int save_boot_params(void)
68 {
69 int ret = setjmp(brom_ctx);
70
71 switch (ret) {
72 case 0:
73 if (check_back_to_brom_dnl_flag())
74 _back_to_bootrom(BROM_BOOT_ENTER_DNL);
75 /*
76 * This is the initial pass through this function
77 * (i.e. saving the context), setjmp just setup up the
78 * brom_ctx: transfer back into the startup-code at
79 * 'save_boot_params_ret' and let the compiler know
80 * that this will not return.
81 */
82 save_boot_params_ret();
83 while (true)
84 /* does not return */;
85 break;
86
87 case BROM_BOOT_NEXTSTAGE:
88 /*
89 * To instruct the BROM to boot the next stage, we
90 * need to return 0 to it: i.e. we need to rewrite
91 * the return code once more.
92 */
93 ret = 0;
94 break;
95 case BROM_BOOT_ENTER_DNL:
96 /*
97 * A non-zero return value will instruct the BROM enter
98 * download mode.
99 */
100 ret = 1;
101 break;
102 default:
103 #if CONFIG_IS_ENABLED(LIBCOMMON_SUPPORT)
104 puts("FATAL: unexpected command to back_to_bootrom()\n");
105 #endif
106 hang();
107 };
108
109 return ret;
110 }
111