summaryrefslogtreecommitdiffstats
path: root/firmware/target/arm/crt0.S
blob: 07d860ed4f89d927c7ded8a0fb2e95a49f738273 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2008 by Marcoen Hirschberg
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/
#include "config.h"
#include "cpu.h"

#if defined(HAVE_BOOTDATA) && !defined(BOOTLOADER)
#include "bootdata.h"
#endif

    .section .init.text,"ax",%progbits

    .global    start
start:
    /* Exception vectors */

    /*
     * reset vector *MUST* use relative-addressing only
     * the MMU might not be enabled yet, and the PC might point to
     * a memory region not present in the linked binary
     */

    b   newstart
    b   undef_instr_handler
    b   software_int_handler
    b   prefetch_abort_handler
    b   data_abort_handler
    b   reserved_handler
    b   irq_handler
    b   fiq_handler

_vectorsend:

    .text

newstart:
    msr     cpsr_c, #0xd3 /* enter supervisor mode, disable IRQ/FIQ */

#if CONFIG_CPU == AS3525 || CONFIG_CPU == AS3525v2
    bl      memory_init
#endif

#ifdef USE_IRAM
    /* Zero out IBSS */
    ldr     r2, =_iedata
    ldr     r3, =_iend
    mov     r4, #0
1:
    cmp     r3, r2
    strhi   r4, [r2], #4
    bhi     1b

    /* Copy the IRAM */
    /* must be done before bss is zeroed */
    ldr     r2, =_iramcopy
    ldr     r3, =_iramstart
    ldr     r4, =_iramend
1:
    cmp     r4, r3
    ldrhi   r5, [r2], #4
    strhi   r5, [r3], #4
    bhi     1b
#endif

#ifdef HAVE_INIT_ATTR
    /* copy init data to codec buffer */
    /* must be done before bss is zeroed */
    ldr    r2, =_initcopy
    ldr    r3, =_initstart
    ldr    r4, =_initend
1:
    cmp     r4, r3
    ldrhi   r5, [r2], #4
    strhi   r5, [r3], #4
    bhi     1b

    mov     r2, #0
    mcr     p15, 0, r2, c7, c5, 0   @ Invalidate ICache
#endif

    /* Initialise bss section to zero */
    ldr     r2, =_edata
    ldr     r3, =_end
    mov     r4, #0
1:
    cmp     r3, r2
    strhi   r4, [r2], #4
    bhi     1b

    /* Set up stack for IRQ mode */
    msr     cpsr_c, #0xd2
    ldr     sp, =irq_stack

    msr     cpsr_c, #0xd3
#if CONFIG_CPU == AS3525 || CONFIG_CPU == AS3525v2
    /* Let abort and undefined modes use irq stack */
    /* svc stack is for interrupt processing */
    ldr     sp, =svc_stack
#else
    /* Let svc, abort and undefined modes use irq stack */
    ldr     sp, =irq_stack

    /* Set up stack for FIQ mode */
    msr     cpsr_c, #0xd1
    ldr     sp, =fiq_stack
#endif
    msr     cpsr_c, #0xd7
    ldr     sp, =irq_stack
    msr     cpsr_c, #0xdb
    ldr     sp, =irq_stack

    /* Switch to sys mode */
    msr     cpsr_c, #0xdf

    /* Set up some stack and munge it with 0xdeadbeef */
    ldr     sp, =stackend
    ldr     r2, =stackbegin
    ldr     r3, =0xdeadbeef
1:
    cmp     sp, r2
    strhi   r3, [r2], #4
    bhi     1b

    ldr     ip, =main       @ make sure we are using the virtual address
    bx      ip

#if defined(HAVE_BOOTDATA) && !defined(BOOTLOADER)
/* boot data structure */
put_boot_data_here
#endif

/* Cache-align interrupt stacks */
.balign    32

/* 256 words of IRQ stack */
    .space 256*4
irq_stack:

/* 256 words of FIQ/SVC stack */
    .space 256*4
fiq_stack:
svc_stack:

end: