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rename CFG_ macros to CONFIG_SYS
[people/ms/u-boot.git] / cpu / arm920t / cpu.c
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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
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36#ifdef CONFIG_USE_IRQ
37DECLARE_GLOBAL_DATA_PTR;
38#endif
39
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40/* read co-processor 15, register #1 (control register) */
41static 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"
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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) */
58static 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"
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65 :
66 : "r" (value)
67 : "memory");
68
69 read_p15_c1 ();
70}
71
72static 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 */
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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 */
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84
85#define C1_BIG_ENDIAN (1<<7) /* big endian off/on */
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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 */
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89#define C1_HIGH_VECTORS (1<<13) /* location of vectors: low/high addresses */
90
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91
92int cpu_init (void)
93{
94 /*
a8c7c708 95 * setup up stacks if necessary
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96 */
97#ifdef CONFIG_USE_IRQ
6d0f6bcf 98 IRQ_STACK_START = _armboot_start - CONFIG_SYS_MALLOC_LEN - CONFIG_SYS_GBL_DATA_SIZE - 4;
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99 FIQ_STACK_START = IRQ_STACK_START - CONFIG_STACKSIZE_IRQ;
100#endif
101 return 0;
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102}
103
104int 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
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126 return (0);
127}
128
129int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
130{
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131 disable_interrupts ();
132 reset_cpu (0);
133 /*NOTREACHED*/
134 return (0);
135}
136
137void icache_enable (void)
138{
139 ulong reg;
140
74f4304e 141 reg = read_p15_c1 (); /* get control reg. */
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142 cp_delay ();
143 write_p15_c1 (reg | C1_IC);
144}
145
146void 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
155int 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 */
162void 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
171void 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
181int dcache_status (void)
182{
183 return (read_p15_c1 () & C1_DC) != 0;
184}
185#endif