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3d818266 WD |
1 | /* |
2 | * (C) Copyright 2002 | |
3 | * Sysgo Real-Time Solutions, GmbH <www.elinos.com> | |
4 | * Marius Groeger <mgroeger@sysgo.de> | |
5 | * | |
6 | * (C) Copyright 2002 | |
7 | * Gary Jennejohn, DENX Software Engineering, <gj@denx.de> | |
8 | * | |
9 | * See file CREDITS for list of people who contributed to this | |
10 | * project. | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or | |
13 | * modify it under the terms of the GNU General Public License as | |
14 | * published by the Free Software Foundation; either version 2 of | |
15 | * the License, or (at your option) any later version. | |
16 | * | |
17 | * This program is distributed in the hope that it will be useful, | |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | * GNU General Public License for more details. | |
21 | * | |
22 | * You should have received a copy of the GNU General Public License | |
23 | * along with this program; if not, write to the Free Software | |
24 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, | |
25 | * MA 02111-1307 USA | |
26 | */ | |
27 | ||
28 | /* | |
29 | * CPU specific code | |
30 | */ | |
31 | ||
32 | #include <common.h> | |
33 | #include <command.h> | |
34 | #include <arm920t.h> | |
35 | ||
d87080b7 WD |
36 | #ifdef CONFIG_USE_IRQ |
37 | DECLARE_GLOBAL_DATA_PTR; | |
38 | #endif | |
39 | ||
3d818266 WD |
40 | /* read co-processor 15, register #1 (control register) */ |
41 | static unsigned long read_p15_c1 (void) | |
42 | { | |
43 | unsigned long value; | |
44 | ||
45 | __asm__ __volatile__( | |
74f4304e | 46 | "mrc p15, 0, %0, c1, c0, 0 @ read control reg\n" |
3d818266 WD |
47 | : "=r" (value) |
48 | : | |
49 | : "memory"); | |
50 | ||
51 | #ifdef MMU_DEBUG | |
52 | printf ("p15/c1 is = %08lx\n", value); | |
53 | #endif | |
54 | return value; | |
55 | } | |
56 | ||
57 | /* write to co-processor 15, register #1 (control register) */ | |
58 | static void write_p15_c1 (unsigned long value) | |
59 | { | |
60 | #ifdef MMU_DEBUG | |
61 | printf ("write %08lx to p15/c1\n", value); | |
62 | #endif | |
63 | __asm__ __volatile__( | |
74f4304e | 64 | "mcr p15, 0, %0, c1, c0, 0 @ write it back\n" |
3d818266 WD |
65 | : |
66 | : "r" (value) | |
67 | : "memory"); | |
68 | ||
69 | read_p15_c1 (); | |
70 | } | |
71 | ||
72 | static void cp_delay (void) | |
73 | { | |
74 | volatile int i; | |
75 | ||
76 | /* copro seems to need some delay between reading and writing */ | |
77 | for (i = 0; i < 100; i++); | |
78 | } | |
79 | ||
74f4304e | 80 | /* See also ARM920T Technical reference Manual */ |
3d818266 WD |
81 | #define C1_MMU (1<<0) /* mmu off/on */ |
82 | #define C1_ALIGN (1<<1) /* alignment faults off/on */ | |
83 | #define C1_DC (1<<2) /* dcache off/on */ | |
74f4304e WD |
84 | |
85 | #define C1_BIG_ENDIAN (1<<7) /* big endian off/on */ | |
3d818266 WD |
86 | #define C1_SYS_PROT (1<<8) /* system protection */ |
87 | #define C1_ROM_PROT (1<<9) /* ROM protection */ | |
88 | #define C1_IC (1<<12) /* icache off/on */ | |
74f4304e WD |
89 | #define C1_HIGH_VECTORS (1<<13) /* location of vectors: low/high addresses */ |
90 | ||
3d818266 WD |
91 | |
92 | int cpu_init (void) | |
93 | { | |
94 | /* | |
a8c7c708 | 95 | * setup up stacks if necessary |
3d818266 WD |
96 | */ |
97 | #ifdef CONFIG_USE_IRQ | |
6d0f6bcf | 98 | IRQ_STACK_START = _armboot_start - CONFIG_SYS_MALLOC_LEN - CONFIG_SYS_GBL_DATA_SIZE - 4; |
a8c7c708 WD |
99 | FIQ_STACK_START = IRQ_STACK_START - CONFIG_STACKSIZE_IRQ; |
100 | #endif | |
101 | return 0; | |
3d818266 WD |
102 | } |
103 | ||
104 | int cleanup_before_linux (void) | |
105 | { | |
106 | /* | |
107 | * this function is called just before we call linux | |
108 | * it prepares the processor for linux | |
109 | * | |
110 | * we turn off caches etc ... | |
111 | */ | |
112 | ||
113 | unsigned long i; | |
114 | ||
115 | disable_interrupts (); | |
116 | ||
117 | /* turn off I/D-cache */ | |
118 | asm ("mrc p15, 0, %0, c1, c0, 0":"=r" (i)); | |
119 | i &= ~(C1_DC | C1_IC); | |
120 | asm ("mcr p15, 0, %0, c1, c0, 0": :"r" (i)); | |
121 | ||
122 | /* flush I/D-cache */ | |
123 | i = 0; | |
124 | asm ("mcr p15, 0, %0, c7, c7, 0": :"r" (i)); | |
74f4304e | 125 | |
3d818266 WD |
126 | return (0); |
127 | } | |
128 | ||
129 | int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) | |
130 | { | |
3d818266 WD |
131 | disable_interrupts (); |
132 | reset_cpu (0); | |
133 | /*NOTREACHED*/ | |
134 | return (0); | |
135 | } | |
136 | ||
137 | void icache_enable (void) | |
138 | { | |
139 | ulong reg; | |
140 | ||
74f4304e | 141 | reg = read_p15_c1 (); /* get control reg. */ |
3d818266 WD |
142 | cp_delay (); |
143 | write_p15_c1 (reg | C1_IC); | |
144 | } | |
145 | ||
146 | void icache_disable (void) | |
147 | { | |
148 | ulong reg; | |
149 | ||
150 | reg = read_p15_c1 (); | |
151 | cp_delay (); | |
152 | write_p15_c1 (reg & ~C1_IC); | |
153 | } | |
154 | ||
155 | int icache_status (void) | |
156 | { | |
157 | return (read_p15_c1 () & C1_IC) != 0; | |
158 | } | |
159 | ||
160 | #ifdef USE_920T_MMU | |
161 | /* It makes no sense to use the dcache if the MMU is not enabled */ | |
162 | void dcache_enable (void) | |
163 | { | |
164 | ulong reg; | |
165 | ||
166 | reg = read_p15_c1 (); | |
167 | cp_delay (); | |
168 | write_p15_c1 (reg | C1_DC); | |
169 | } | |
170 | ||
171 | void dcache_disable (void) | |
172 | { | |
173 | ulong reg; | |
174 | ||
175 | reg = read_p15_c1 (); | |
176 | cp_delay (); | |
177 | reg &= ~C1_DC; | |
178 | write_p15_c1 (reg); | |
179 | } | |
180 | ||
181 | int dcache_status (void) | |
182 | { | |
183 | return (read_p15_c1 () & C1_DC) != 0; | |
184 | } | |
185 | #endif |