blob: 4c3a94af572c58b4938885c0258b8ddd9ce13053 [file] [log] [blame]
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +00001/*
2 * crt0 - C-runtime startup Code for ARM U-Boot
3 *
4 * Copyright (c) 2012 Albert ARIBAUD <albert.u.boot@aribaud.net>
5 *
Wolfgang Denk1a459662013-07-08 09:37:19 +02006 * SPDX-License-Identifier: GPL-2.0+
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +00007 */
8
9#include <config.h>
10#include <asm-offsets.h>
Benoît Thébaudeau9c5feab2013-04-11 09:35:47 +000011#include <linux/linkage.h>
rev13@wp.pl12d8a722015-03-01 12:44:39 +010012#ifdef CONFIG_CPU_V7M
13#include <asm/armv7m.h>
14#endif
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +000015
16/*
17 * This file handles the target-independent stages of the U-Boot
18 * start-up where a C runtime environment is needed. Its entry point
19 * is _main and is branched into from the target's start.S file.
20 *
21 * _main execution sequence is:
22 *
23 * 1. Set up initial environment for calling board_init_f().
24 * This environment only provides a stack and a place to store
25 * the GD ('global data') structure, both located in some readily
26 * available RAM (SRAM, locked cache...). In this context, VARIABLE
27 * global data, initialized or not (BSS), are UNAVAILABLE; only
Simon Glassed641902015-08-01 08:55:46 -060028 * CONSTANT initialized data are available. GD should be zeroed
29 * before board_init_f() is called.
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +000030 *
31 * 2. Call board_init_f(). This function prepares the hardware for
32 * execution from system RAM (DRAM, DDR...) As system RAM may not
33 * be available yet, , board_init_f() must use the current GD to
34 * store any data which must be passed on to later stages. These
35 * data include the relocation destination, the future stack, and
36 * the future GD location.
37 *
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +000038 * 3. Set up intermediate environment where the stack and GD are the
39 * ones allocated by board_init_f() in system RAM, but BSS and
40 * initialized non-const data are still not available.
41 *
Simon Glassed641902015-08-01 08:55:46 -060042 * 4a.For U-Boot proper (not SPL), call relocate_code(). This function
43 * relocates U-Boot from its current location into the relocation
44 * destination computed by board_init_f().
45 *
46 * 4b.For SPL, board_init_f() just returns (to crt0). There is no
47 * code relocation in SPL.
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +000048 *
49 * 5. Set up final environment for calling board_init_r(). This
50 * environment has BSS (initialized to 0), initialized non-const
51 * data (initialized to their intended value), and stack in system
Simon Glassed641902015-08-01 08:55:46 -060052 * RAM (for SPL moving the stack and GD into RAM is optional - see
53 * CONFIG_SPL_STACK_R). GD has retained values set by board_init_f().
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +000054 *
Simon Glassed641902015-08-01 08:55:46 -060055 * 6. For U-Boot proper (not SPL), some CPUs have some work left to do
56 * at this point regarding memory, so call c_runtime_cpu_setup.
57 *
58 * 7. Branch to board_init_r().
59 *
60 * For more information see 'Board Initialisation Flow in README.
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +000061 */
62
63/*
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +000064 * entry point of crt0 sequence
65 */
66
Benoît Thébaudeau9c5feab2013-04-11 09:35:47 +000067ENTRY(_main)
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +000068
69/*
70 * Set up initial C runtime environment and call board_init_f(0).
71 */
72
Benoît Thébaudeau66f30bf2013-04-11 09:36:01 +000073#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_STACK)
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +000074 ldr sp, =(CONFIG_SPL_STACK)
75#else
76 ldr sp, =(CONFIG_SYS_INIT_SP_ADDR)
77#endif
rev13@wp.pl12d8a722015-03-01 12:44:39 +010078#if defined(CONFIG_CPU_V7M) /* v7M forbids using SP as BIC destination */
79 mov r3, sp
80 bic r3, r3, #7
81 mov sp, r3
82#else
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +000083 bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
rev13@wp.pl12d8a722015-03-01 12:44:39 +010084#endif
Simon Glassaae2aef2014-07-10 22:23:26 -060085 mov r2, sp
Andreas Bießmann6ba2bc82013-11-27 16:09:29 +010086 sub sp, sp, #GD_SIZE /* allocate one GD above SP */
rev13@wp.pl12d8a722015-03-01 12:44:39 +010087#if defined(CONFIG_CPU_V7M) /* v7M forbids using SP as BIC destination */
88 mov r3, sp
89 bic r3, r3, #7
90 mov sp, r3
91#else
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +000092 bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
rev13@wp.pl12d8a722015-03-01 12:44:39 +010093#endif
Jeroen Hofsteefe1378a2013-09-21 14:04:41 +020094 mov r9, sp /* GD is above SP */
Simon Glassaae2aef2014-07-10 22:23:26 -060095 mov r1, sp
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +000096 mov r0, #0
Simon Glassaae2aef2014-07-10 22:23:26 -060097clr_gd:
98 cmp r1, r2 /* while not at end of GD */
rev13@wp.pl12d8a722015-03-01 12:44:39 +010099#if defined(CONFIG_CPU_V7M)
100 itt lo
101#endif
Simon Glassaae2aef2014-07-10 22:23:26 -0600102 strlo r0, [r1] /* clear 32-bit GD word */
103 addlo r1, r1, #4 /* move to next */
104 blo clr_gd
Simon Glassba195992014-11-10 17:16:44 -0700105#if defined(CONFIG_SYS_MALLOC_F_LEN)
Simon Glass76a1e5842014-07-10 22:23:29 -0600106 sub sp, sp, #CONFIG_SYS_MALLOC_F_LEN
107 str sp, [r9, #GD_MALLOC_BASE]
108#endif
Simon Glassaae2aef2014-07-10 22:23:26 -0600109 /* mov r0, #0 not needed due to above code */
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +0000110 bl board_init_f
111
112#if ! defined(CONFIG_SPL_BUILD)
113
114/*
115 * Set up intermediate environment (new sp and gd) and call
Benoît Thébaudeau5c6db122013-04-11 09:35:53 +0000116 * relocate_code(addr_moni). Trick here is that we'll return
117 * 'here' but relocated.
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +0000118 */
119
Jeroen Hofsteefe1378a2013-09-21 14:04:41 +0200120 ldr sp, [r9, #GD_START_ADDR_SP] /* sp = gd->start_addr_sp */
rev13@wp.pl12d8a722015-03-01 12:44:39 +0100121#if defined(CONFIG_CPU_V7M) /* v7M forbids using SP as BIC destination */
122 mov r3, sp
123 bic r3, r3, #7
124 mov sp, r3
125#else
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +0000126 bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
rev13@wp.pl12d8a722015-03-01 12:44:39 +0100127#endif
Jeroen Hofsteefe1378a2013-09-21 14:04:41 +0200128 ldr r9, [r9, #GD_BD] /* r9 = gd->bd */
129 sub r9, r9, #GD_SIZE /* new GD is below bd */
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +0000130
131 adr lr, here
Jeroen Hofsteefe1378a2013-09-21 14:04:41 +0200132 ldr r0, [r9, #GD_RELOC_OFF] /* r0 = gd->reloc_off */
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +0000133 add lr, lr, r0
rev13@wp.pl12d8a722015-03-01 12:44:39 +0100134#if defined(CONFIG_CPU_V7M)
135 orr lr, #1 /* As required by Thumb-only */
136#endif
Jeroen Hofsteefe1378a2013-09-21 14:04:41 +0200137 ldr r0, [r9, #GD_RELOCADDR] /* r0 = gd->relocaddr */
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +0000138 b relocate_code
139here:
Albert ARIBAUDdb544b92014-11-13 17:59:15 +0100140/*
141 * now relocate vectors
142 */
143
144 bl relocate_vectors
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +0000145
146/* Set up final (full) environment */
147
148 bl c_runtime_cpu_setup /* we still call old routine here */
Simon Glassdb910352015-03-03 08:03:00 -0700149#endif
150#if !defined(CONFIG_SPL_BUILD) || defined(CONFIG_SPL_FRAMEWORK)
151# ifdef CONFIG_SPL_BUILD
152 /* Use a DRAM stack for the rest of SPL, if requested */
153 bl spl_relocate_stack_gd
154 cmp r0, #0
155 movne sp, r0
156# endif
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +0000157 ldr r0, =__bss_start /* this is auto-relocated! */
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +0000158
Przemyslaw Marczak114c86d2015-03-04 14:01:22 +0100159#ifdef CONFIG_USE_ARCH_MEMSET
160 ldr r3, =__bss_end /* this is auto-relocated! */
161 mov r1, #0x00000000 /* prepare zero to clear BSS */
162
163 subs r2, r3, r0 /* r2 = memset len */
164 bl memset
165#else
166 ldr r1, =__bss_end /* this is auto-relocated! */
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +0000167 mov r2, #0x00000000 /* prepare zero to clear BSS */
168
169clbss_l:cmp r0, r1 /* while not at end of BSS */
rev13@wp.pl12d8a722015-03-01 12:44:39 +0100170#if defined(CONFIG_CPU_V7M)
171 itt lo
172#endif
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +0000173 strlo r2, [r0] /* clear 32-bit BSS word */
174 addlo r0, r0, #4 /* move to next */
175 blo clbss_l
Przemyslaw Marczak114c86d2015-03-04 14:01:22 +0100176#endif
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +0000177
Simon Glassdb910352015-03-03 08:03:00 -0700178#if ! defined(CONFIG_SPL_BUILD)
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +0000179 bl coloured_LED_init
180 bl red_led_on
Simon Glassdb910352015-03-03 08:03:00 -0700181#endif
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +0000182 /* call board_init_r(gd_t *id, ulong dest_addr) */
Jeroen Hofsteefe1378a2013-09-21 14:04:41 +0200183 mov r0, r9 /* gd_t */
184 ldr r1, [r9, #GD_RELOCADDR] /* dest_addr */
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +0000185 /* call board_init_r */
186 ldr pc, =board_init_r /* this is auto-relocated! */
187
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +0000188 /* we should not return here. */
Albert ARIBAUDe05e5de2013-01-08 10:18:02 +0000189#endif
Benoît Thébaudeau9c5feab2013-04-11 09:35:47 +0000190
191ENDPROC(_main)