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Tom Rini10e47792018-05-06 17:58:06 -04001/* SPDX-License-Identifier: GPL-2.0+ */
Albert ARIBAUDfacdae52013-01-08 10:18:02 +00002/*
3 * crt0 - C-runtime startup Code for ARM U-Boot
4 *
5 * Copyright (c) 2012 Albert ARIBAUD <albert.u.boot@aribaud.net>
Albert ARIBAUDfacdae52013-01-08 10:18:02 +00006 */
7
8#include <config.h>
9#include <asm-offsets.h>
Benoît Thébaudeau73dcb272013-04-11 09:35:47 +000010#include <linux/linkage.h>
Vikas Manocha976e3422018-08-31 16:57:06 -070011#include <asm/assembler.h>
Albert ARIBAUDfacdae52013-01-08 10:18:02 +000012
13/*
14 * This file handles the target-independent stages of the U-Boot
15 * start-up where a C runtime environment is needed. Its entry point
16 * is _main and is branched into from the target's start.S file.
17 *
18 * _main execution sequence is:
19 *
20 * 1. Set up initial environment for calling board_init_f().
21 * This environment only provides a stack and a place to store
22 * the GD ('global data') structure, both located in some readily
23 * available RAM (SRAM, locked cache...). In this context, VARIABLE
24 * global data, initialized or not (BSS), are UNAVAILABLE; only
Simon Glasscb60ae82015-08-01 08:55:46 -060025 * CONSTANT initialized data are available. GD should be zeroed
26 * before board_init_f() is called.
Albert ARIBAUDfacdae52013-01-08 10:18:02 +000027 *
28 * 2. Call board_init_f(). This function prepares the hardware for
29 * execution from system RAM (DRAM, DDR...) As system RAM may not
30 * be available yet, , board_init_f() must use the current GD to
31 * store any data which must be passed on to later stages. These
32 * data include the relocation destination, the future stack, and
33 * the future GD location.
34 *
Albert ARIBAUDfacdae52013-01-08 10:18:02 +000035 * 3. Set up intermediate environment where the stack and GD are the
36 * ones allocated by board_init_f() in system RAM, but BSS and
37 * initialized non-const data are still not available.
38 *
Simon Glasscb60ae82015-08-01 08:55:46 -060039 * 4a.For U-Boot proper (not SPL), call relocate_code(). This function
40 * relocates U-Boot from its current location into the relocation
41 * destination computed by board_init_f().
42 *
43 * 4b.For SPL, board_init_f() just returns (to crt0). There is no
44 * code relocation in SPL.
Albert ARIBAUDfacdae52013-01-08 10:18:02 +000045 *
46 * 5. Set up final environment for calling board_init_r(). This
47 * environment has BSS (initialized to 0), initialized non-const
48 * data (initialized to their intended value), and stack in system
Simon Glasscb60ae82015-08-01 08:55:46 -060049 * RAM (for SPL moving the stack and GD into RAM is optional - see
50 * CONFIG_SPL_STACK_R). GD has retained values set by board_init_f().
51 *
52 * 6. For U-Boot proper (not SPL), some CPUs have some work left to do
53 * at this point regarding memory, so call c_runtime_cpu_setup.
54 *
55 * 7. Branch to board_init_r().
Albert ARIBAUDfacdae52013-01-08 10:18:02 +000056 *
Simon Glasscb60ae82015-08-01 08:55:46 -060057 * For more information see 'Board Initialisation Flow in README.
Albert ARIBAUDfacdae52013-01-08 10:18:02 +000058 */
59
60/*
Andreas Dannenbergaa4ad4b2019-06-04 17:55:45 -050061 * Macro for clearing BSS during SPL execution. Usually called during the
62 * relocation process for most boards before entering board_init_r(), but
63 * can also be done early before entering board_init_f() on plaforms that
64 * can afford it due to sufficient memory being available early.
65 */
66
67.macro SPL_CLEAR_BSS
68 ldr r0, =__bss_start /* this is auto-relocated! */
69
70#ifdef CONFIG_USE_ARCH_MEMSET
71 ldr r3, =__bss_end /* this is auto-relocated! */
72 mov r1, #0x00000000 /* prepare zero to clear BSS */
73
74 subs r2, r3, r0 /* r2 = memset len */
75 bl memset
76#else
77 ldr r1, =__bss_end /* this is auto-relocated! */
78 mov r2, #0x00000000 /* prepare zero to clear BSS */
79
80clbss_l:cmp r0, r1 /* while not at end of BSS */
81 strlo r2, [r0] /* clear 32-bit BSS word */
82 addlo r0, r0, #4 /* move to next */
83 blo clbss_l
84#endif
85.endm
86
87/*
Albert ARIBAUDfacdae52013-01-08 10:18:02 +000088 * entry point of crt0 sequence
89 */
90
Benoît Thébaudeau73dcb272013-04-11 09:35:47 +000091ENTRY(_main)
Albert ARIBAUDfacdae52013-01-08 10:18:02 +000092
93/*
94 * Set up initial C runtime environment and call board_init_f(0).
95 */
96
Kever Yang94ddd962019-04-02 20:41:21 +080097#if defined(CONFIG_TPL_BUILD) && defined(CONFIG_TPL_NEEDS_SEPARATE_STACK)
98 ldr r0, =(CONFIG_TPL_STACK)
99#elif defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_STACK)
Vikas Manocha40eb6912016-02-05 10:43:01 -0800100 ldr r0, =(CONFIG_SPL_STACK)
Albert ARIBAUDfacdae52013-01-08 10:18:02 +0000101#else
Vikas Manocha40eb6912016-02-05 10:43:01 -0800102 ldr r0, =(CONFIG_SYS_INIT_SP_ADDR)
Albert ARIBAUDfacdae52013-01-08 10:18:02 +0000103#endif
Vikas Manocha40eb6912016-02-05 10:43:01 -0800104 bic r0, r0, #7 /* 8-byte alignment for ABI compliance */
105 mov sp, r0
Albert ARIBAUD6cb4c462015-11-25 17:56:32 +0100106 bl board_init_f_alloc_reserve
Simon Glass35375d42015-10-19 06:50:00 -0600107 mov sp, r0
Albert ARIBAUD85260bb2015-11-25 17:56:33 +0100108 /* set up gd here, outside any C code */
109 mov r9, r0
Albert ARIBAUD6cb4c462015-11-25 17:56:32 +0100110 bl board_init_f_init_reserve
Simon Glass35375d42015-10-19 06:50:00 -0600111
Andreas Dannenbergaa4ad4b2019-06-04 17:55:45 -0500112#if defined(CONFIG_SPL_EARLY_BSS)
113 SPL_CLEAR_BSS
114#endif
115
Albert ARIBAUDfacdae52013-01-08 10:18:02 +0000116 mov r0, #0
117 bl board_init_f
118
119#if ! defined(CONFIG_SPL_BUILD)
120
121/*
122 * Set up intermediate environment (new sp and gd) and call
Benoît Thébaudeaua0436612013-04-11 09:35:53 +0000123 * relocate_code(addr_moni). Trick here is that we'll return
124 * 'here' but relocated.
Albert ARIBAUDfacdae52013-01-08 10:18:02 +0000125 */
126
Vikas Manocha40eb6912016-02-05 10:43:01 -0800127 ldr r0, [r9, #GD_START_ADDR_SP] /* sp = gd->start_addr_sp */
128 bic r0, r0, #7 /* 8-byte alignment for ABI compliance */
129 mov sp, r0
Jeroen Hofsteef2d60762013-09-21 14:04:41 +0200130 ldr r9, [r9, #GD_BD] /* r9 = gd->bd */
131 sub r9, r9, #GD_SIZE /* new GD is below bd */
Albert ARIBAUDfacdae52013-01-08 10:18:02 +0000132
133 adr lr, here
Jeroen Hofsteef2d60762013-09-21 14:04:41 +0200134 ldr r0, [r9, #GD_RELOC_OFF] /* r0 = gd->reloc_off */
Albert ARIBAUDfacdae52013-01-08 10:18:02 +0000135 add lr, lr, r0
rev13@wp.plb3b57e82015-03-01 12:44:39 +0100136#if defined(CONFIG_CPU_V7M)
137 orr lr, #1 /* As required by Thumb-only */
138#endif
Jeroen Hofsteef2d60762013-09-21 14:04:41 +0200139 ldr r0, [r9, #GD_RELOCADDR] /* r0 = gd->relocaddr */
Albert ARIBAUDfacdae52013-01-08 10:18:02 +0000140 b relocate_code
141here:
Albert ARIBAUDbd6e56f2014-11-13 17:59:15 +0100142/*
143 * now relocate vectors
144 */
145
146 bl relocate_vectors
Albert ARIBAUDfacdae52013-01-08 10:18:02 +0000147
148/* Set up final (full) environment */
149
150 bl c_runtime_cpu_setup /* we still call old routine here */
Simon Glassd8711af2015-03-03 08:03:00 -0700151#endif
152#if !defined(CONFIG_SPL_BUILD) || defined(CONFIG_SPL_FRAMEWORK)
Andreas Dannenbergaa4ad4b2019-06-04 17:55:45 -0500153
154#if !defined(CONFIG_SPL_EARLY_BSS)
155 SPL_CLEAR_BSS
156#endif
157
Simon Glassd8711af2015-03-03 08:03:00 -0700158# ifdef CONFIG_SPL_BUILD
159 /* Use a DRAM stack for the rest of SPL, if requested */
160 bl spl_relocate_stack_gd
161 cmp r0, #0
162 movne sp, r0
Albert ARIBAUD85260bb2015-11-25 17:56:33 +0100163 movne r9, r0
Simon Glassd8711af2015-03-03 08:03:00 -0700164# endif
Albert ARIBAUDfacdae52013-01-08 10:18:02 +0000165
Simon Glassd8711af2015-03-03 08:03:00 -0700166#if ! defined(CONFIG_SPL_BUILD)
Albert ARIBAUDfacdae52013-01-08 10:18:02 +0000167 bl coloured_LED_init
168 bl red_led_on
Simon Glassd8711af2015-03-03 08:03:00 -0700169#endif
Albert ARIBAUDfacdae52013-01-08 10:18:02 +0000170 /* call board_init_r(gd_t *id, ulong dest_addr) */
Jeroen Hofsteef2d60762013-09-21 14:04:41 +0200171 mov r0, r9 /* gd_t */
172 ldr r1, [r9, #GD_RELOCADDR] /* dest_addr */
Albert ARIBAUDfacdae52013-01-08 10:18:02 +0000173 /* call board_init_r */
Tom Rini1c640a62017-03-18 09:01:44 -0400174#if CONFIG_IS_ENABLED(SYS_THUMB_BUILD)
David Müller (ELSOFT AG)408a12d2016-02-09 16:48:28 +0100175 ldr lr, =board_init_r /* this is auto-relocated! */
176 bx lr
177#else
Albert ARIBAUDfacdae52013-01-08 10:18:02 +0000178 ldr pc, =board_init_r /* this is auto-relocated! */
David Müller (ELSOFT AG)408a12d2016-02-09 16:48:28 +0100179#endif
Albert ARIBAUDfacdae52013-01-08 10:18:02 +0000180 /* we should not return here. */
Albert ARIBAUDfacdae52013-01-08 10:18:02 +0000181#endif
Benoît Thébaudeau73dcb272013-04-11 09:35:47 +0000182
183ENDPROC(_main)