summaryrefslogtreecommitdiffstats
path: root/firmware/target/mips/ingenic_jz47xx/crt0.S
blob: 8df00811cbe4610441afee19c805ac2d09961c3f (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
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2008 by Maurus Cuelenaere
 *
 * 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.
 *
 ****************************************************************************/

/*
 * init.S
 *
 * Initialization code for JzRISC.
 *
 * Author: Seeger Chin
 * e-mail: seeger.chin@gmail.com
 *
 * Copyright (C) 2006 Ingenic Semiconductor Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include "config.h"
#include "mips.h"

    .text

    .extern system_main
    .extern main
    .global _start

    .section .init.text
    .set    push
    .set    mips32
    .set    noreorder
    .set    noat

#ifdef BOOTLOADER
#ifndef XDUOO_X3
    /* These will get filled in by scramble */
    .word 0 /* Empty    */
    .word 0 /* Filesize */

    /* Relocate bootloader */
    la     t0, (_loadaddress-0xE00000)
    la     t1, _loadaddress
    la     t2, _bootend
_relocate_loop:
    lw     t3, 0(t0)
    addiu  t1, 4
    addiu  t0, 4
    bne    t1, t2, _relocate_loop
    sw     t3, -4(t1)
#endif
#endif

_start:
    la      ra, _start
    /*
      ----------------------------------------------------
       Init CP0 registers.
      ----------------------------------------------------
    */
    mtc0    zero, C0_WATCHLO
    mtc0    zero, C0_WATCHHI

    li      t0, (M_StatusBEV  | M_StatusIM7 | M_StatusIM6 \
                | M_StatusIM5 | M_StatusIM4 | M_StatusIM3 \
                | M_StatusIM2 | M_StatusERL)
             /*
                 BEV = Enable Boot Exception Vectors
                 IMx = Interrupt mask
                 ERL = Denotes error level
             */
    mtc0    t0, C0_STATUS

    li      t0, M_CauseIV
    mtc0    t0, C0_CAUSE

    /*
      ----------------------------------------------------
       Init caches, assumes a 4way*128set*32byte I/D cache
      ----------------------------------------------------
    */
    li      t0, 3            # enable cache for kseg0 accesses
    mtc0    t0, C0_CONFIG    # CONFIG reg
    la      t0, 0x80000000   # an idx op should use an unmappable address
    ori     t1, t0, 0x4000   # 16kB cache
    mtc0    zero, C0_TAGLO   # TAGLO reg
    mtc0    zero, C0_TAGHI   # TAGHI reg

_cache_loop:
    cache   0x8, 0(t0)       # index store icache tag
    cache   0x9, 0(t0)       # index store dcache tag
    addiu   t0, t0, 0x20     # 32 bytes per cache line
    bne     t0, t1, _cache_loop
    ssnop

    /*
      ----------------------------------------------------
       Invalidate BTB
      ----------------------------------------------------
    */
    mfc0    t0, C0_CONFIG
    ssnop
    ori     t0, 2
    mtc0    t0, C0_CONFIG
    ssnop

    /*
      ----------------------------------------------------
       Copy IRAM section
        * copy IRAM first before BSS gets cleared, as both
          have the same address
      ----------------------------------------------------
    */
    la     t0, _iramcopy
    la     t1, _iramstart
    la     t2, _iramend
_iram_loop:
    lw     t3, 0(t0)
    addiu  t1, 4
    addiu  t0, 4
    bne    t1, t2, _iram_loop
    sw     t3, -4(t1)

    /*
      ----------------------------------------------------
       Clear BSS section
      ----------------------------------------------------
    */
    la     t0, _edata
    la     t1, _end
_bss_loop:
    addiu  t0, 4
    bne    t0, t1, _bss_loop
    sw     zero, -4(t0)

    /*
      ----------------------------------------------------
       Set up stack
      ----------------------------------------------------
    */
    la      sp, stackend
    la      t0, stackbegin
    li      t2, 0xDEADBEEF

_stack_loop:
    addiu   t0, 4
    bne     t0, sp, _stack_loop
    sw      t2, -4(t0)

    /*
      ----------------------------------------------------
       Set up interrupt stack
      ----------------------------------------------------
    */
    la     k0, _irqstackend
    la     t0, _irqstackbegin

_irq_stack_loop:
    addiu  t0, 4
    bne    t0, k0, _irq_stack_loop
    sw     t2, -4(t0)

    /*
      ----------------------------------------------------
       Jump to C code
      ----------------------------------------------------
    */
    jal     system_main  /* Init clocks etc first */
    ssnop
    j       main
    move    ra, zero     /* init backtrace root */

    .set pop