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
|
/*
* (C) Copyright 2002
* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
* Marius Groeger <mgroeger@sysgo.de>
*
* (C) Copyright 2002
* Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
*
* See file CREDITS for list of people who contributed to this
* project.
*
* 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 program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
/*
* CPU specific code
*/
#include <common.h>
#include <command.h>
#include <arm920t.h>
#ifdef CONFIG_USE_IRQ
DECLARE_GLOBAL_DATA_PTR;
#endif
/* read co-processor 15, register #1 (control register) */
static unsigned long read_p15_c1 (void)
{
unsigned long value;
__asm__ __volatile__(
"mrc p15, 0, %0, c1, c0, 0 @ read control reg\n"
: "=r" (value)
:
: "memory");
#ifdef MMU_DEBUG
printf ("p15/c1 is = %08lx\n", value);
#endif
return value;
}
/* write to co-processor 15, register #1 (control register) */
static void write_p15_c1 (unsigned long value)
{
#ifdef MMU_DEBUG
printf ("write %08lx to p15/c1\n", value);
#endif
__asm__ __volatile__(
"mcr p15, 0, %0, c1, c0, 0 @ write it back\n"
:
: "r" (value)
: "memory");
read_p15_c1 ();
}
static void cp_delay (void)
{
volatile int i;
/* copro seems to need some delay between reading and writing */
for (i = 0; i < 100; i++);
}
/* See also ARM920T Technical reference Manual */
#define C1_MMU (1<<0) /* mmu off/on */
#define C1_ALIGN (1<<1) /* alignment faults off/on */
#define C1_DC (1<<2) /* dcache off/on */
#define C1_BIG_ENDIAN (1<<7) /* big endian off/on */
#define C1_SYS_PROT (1<<8) /* system protection */
#define C1_ROM_PROT (1<<9) /* ROM protection */
#define C1_IC (1<<12) /* icache off/on */
#define C1_HIGH_VECTORS (1<<13) /* location of vectors: low/high addresses */
int cpu_init (void)
{
/*
* setup up stacks if necessary
*/
#ifdef CONFIG_USE_IRQ
IRQ_STACK_START = _armboot_start - CONFIG_SYS_MALLOC_LEN - CONFIG_SYS_GBL_DATA_SIZE - 4;
FIQ_STACK_START = IRQ_STACK_START - CONFIG_STACKSIZE_IRQ;
#endif
return 0;
}
int cleanup_before_linux (void)
{
/*
* this function is called just before we call linux
* it prepares the processor for linux
*
* we turn off caches etc ...
*/
unsigned long i;
disable_interrupts ();
/* turn off I/D-cache */
asm ("mrc p15, 0, %0, c1, c0, 0":"=r" (i));
i &= ~(C1_DC | C1_IC);
asm ("mcr p15, 0, %0, c1, c0, 0": :"r" (i));
/* flush I/D-cache */
i = 0;
asm ("mcr p15, 0, %0, c7, c7, 0": :"r" (i));
return (0);
}
int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
{
disable_interrupts ();
reset_cpu (0);
/*NOTREACHED*/
return (0);
}
void icache_enable (void)
{
ulong reg;
reg = read_p15_c1 (); /* get control reg. */
cp_delay ();
write_p15_c1 (reg | C1_IC);
}
void icache_disable (void)
{
ulong reg;
reg = read_p15_c1 ();
cp_delay ();
write_p15_c1 (reg & ~C1_IC);
}
int icache_status (void)
{
return (read_p15_c1 () & C1_IC) != 0;
}
#ifdef USE_920T_MMU
/* It makes no sense to use the dcache if the MMU is not enabled */
void dcache_enable (void)
{
ulong reg;
reg = read_p15_c1 ();
cp_delay ();
write_p15_c1 (reg | C1_DC);
}
void dcache_disable (void)
{
ulong reg;
reg = read_p15_c1 ();
cp_delay ();
reg &= ~C1_DC;
write_p15_c1 (reg);
}
int dcache_status (void)
{
return (read_p15_c1 () & C1_DC) != 0;
}
#endif
|
