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wdenk3d818262002-09-22 23:07:35 +00001/*
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
36/* read co-processor 15, register #1 (control register) */
37static unsigned long read_p15_c1 (void)
38{
39 unsigned long value;
40
41 __asm__ __volatile__(
42 "mrc p15, 0, %0, c1, c0, 0 @ read control reg\n"
43 : "=r" (value)
44 :
45 : "memory");
46
47#ifdef MMU_DEBUG
48 printf ("p15/c1 is = %08lx\n", value);
49#endif
50 return value;
51}
52
53/* write to co-processor 15, register #1 (control register) */
54static void write_p15_c1 (unsigned long value)
55{
56#ifdef MMU_DEBUG
57 printf ("write %08lx to p15/c1\n", value);
58#endif
59 __asm__ __volatile__(
60 "mcr p15, 0, %0, c1, c0, 0 @ write it back\n"
61 :
62 : "r" (value)
63 : "memory");
64
65 read_p15_c1 ();
66}
67
68static void cp_delay (void)
69{
70 volatile int i;
71
72 /* copro seems to need some delay between reading and writing */
73 for (i = 0; i < 100; i++);
74}
75
76/* See also ARM Ref. Man. */
77#define C1_MMU (1<<0) /* mmu off/on */
78#define C1_ALIGN (1<<1) /* alignment faults off/on */
79#define C1_DC (1<<2) /* dcache off/on */
80#define C1_BIG_ENDIAN (1<<7) /* big endian off/on */
81#define C1_SYS_PROT (1<<8) /* system protection */
82#define C1_ROM_PROT (1<<9) /* ROM protection */
83#define C1_IC (1<<12) /* icache off/on */
84#define C1_HIGH_VECTORS (1<<13) /* location of vectors: low/high addresses */
85#define RESERVED_1 (0xf << 3) /* must be 111b for R/W */
86
87int cpu_init (void)
88{
89 /*
90 * setup up stack if necessary
91 */
92#ifdef CONFIG_USE_IRQ
93 IRQ_STACK_START = _armboot_end +
94 CONFIG_STACKSIZE + CONFIG_STACKSIZE_IRQ - 4;
95 FIQ_STACK_START = IRQ_STACK_START + CONFIG_STACKSIZE_FIQ;
96 _armboot_real_end = FIQ_STACK_START + 4;
97#else
98 _armboot_real_end = _armboot_end + CONFIG_STACKSIZE;
99#endif /* CONFIG_USE_IRQ */
100 return (0);
101}
102
103int cleanup_before_linux (void)
104{
105 /*
106 * this function is called just before we call linux
107 * it prepares the processor for linux
108 *
109 * we turn off caches etc ...
110 */
111
112 unsigned long i;
113
114 disable_interrupts ();
115
116 /* turn off I/D-cache */
117 asm ("mrc p15, 0, %0, c1, c0, 0":"=r" (i));
118 i &= ~(C1_DC | C1_IC);
119 asm ("mcr p15, 0, %0, c1, c0, 0": :"r" (i));
120
121 /* flush I/D-cache */
122 i = 0;
123 asm ("mcr p15, 0, %0, c7, c7, 0": :"r" (i));
124 return (0);
125}
126
127int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
128{
129 extern void reset_cpu (ulong addr);
130
131 disable_interrupts ();
132 reset_cpu (0);
133 /*NOTREACHED*/
134 return (0);
135}
136
137void icache_enable (void)
138{
139 ulong reg;
140
141 reg = read_p15_c1 ();
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