aboutsummaryrefslogtreecommitdiff
path: root/arch/mips/kernel/spram.c
blob: 8489c88f9932310b7732e1ec396ca2fb2000078c (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
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
/*
 * MIPS SPRAM support
 *
 * 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.
 *
 * Copyright (C) 2007, 2008 MIPS Technologies, Inc.
 */
#include <linux/kernel.h>
#include <linux/ptrace.h>
#include <linux/stddef.h>

#include <asm/fpu.h>
#include <asm/mipsregs.h>
#include <asm/r4kcache.h>
#include <asm/hazards.h>

/*
 * These definitions are correct for the 24K/34K/74K SPRAM sample
 * implementation. The 4KS interpreted the tags differently...
 */
#define SPRAM_TAG0_ENABLE	0x00000080
#define SPRAM_TAG0_PA_MASK	0xfffff000
#define SPRAM_TAG1_SIZE_MASK	0xfffff000

#define SPRAM_TAG_STRIDE	8

#define ERRCTL_SPRAM		(1 << 28)

/* errctl access */
#define read_c0_errctl(x) read_c0_ecc(x)
#define write_c0_errctl(x) write_c0_ecc(x)

/*
 * Different semantics to the set_c0_* function built by __BUILD_SET_C0
 */
static unsigned int bis_c0_errctl(unsigned int set)
{
	unsigned int res;
	res = read_c0_errctl();
	write_c0_errctl(res | set);
	return res;
}

static void ispram_store_tag(unsigned int offset, unsigned int data)
{
	unsigned int errctl;

	/* enable SPRAM tag access */
	errctl = bis_c0_errctl(ERRCTL_SPRAM);
	ehb();

	write_c0_taglo(data);
	ehb();

	cache_op(Index_Store_Tag_I, CKSEG0|offset);
	ehb();

	write_c0_errctl(errctl);
	ehb();
}


static unsigned int ispram_load_tag(unsigned int offset)
{
	unsigned int data;
	unsigned int errctl;

	/* enable SPRAM tag access */
	errctl = bis_c0_errctl(ERRCTL_SPRAM);
	ehb();
	cache_op(Index_Load_Tag_I, CKSEG0 | offset);
	ehb();
	data = read_c0_taglo();
	ehb();
	write_c0_errctl(errctl);
	ehb();

	return data;
}

static void dspram_store_tag(unsigned int offset, unsigned int data)
{
	unsigned int errctl;

	/* enable SPRAM tag access */
	errctl = bis_c0_errctl(ERRCTL_SPRAM);
	ehb();
	write_c0_dtaglo(data);
	ehb();
	cache_op(Index_Store_Tag_D, CKSEG0 | offset);
	ehb();
	write_c0_errctl(errctl);
	ehb();
}


static unsigned int dspram_load_tag(unsigned int offset)
{
	unsigned int data;
	unsigned int errctl;

	errctl = bis_c0_errctl(ERRCTL_SPRAM);
	ehb();
	cache_op(Index_Load_Tag_D, CKSEG0 | offset);
	ehb();
	data = read_c0_dtaglo();
	ehb();
	write_c0_errctl(errctl);
	ehb();

	return data;
}

static void probe_spram(char *type,
	    unsigned int base,
	    unsigned int (*read)(unsigned int),
	    void (*write)(unsigned int, unsigned int))
{
	unsigned int firstsize = 0, lastsize = 0;
	unsigned int firstpa = 0, lastpa = 0, pa = 0;
	unsigned int offset = 0;
	unsigned int size, tag0, tag1;
	unsigned int enabled;
	int i;

	/*
	 * The limit is arbitrary but avoids the loop running away if
	 * the SPRAM tags are implemented differently
	 */

	for (i = 0; i < 8; i++) {
		tag0 = read(offset);
		tag1 = read(offset+SPRAM_TAG_STRIDE);
		pr_debug("DBG %s%d: tag0=%08x tag1=%08x\n",
			 type, i, tag0, tag1);

		size = tag1 & SPRAM_TAG1_SIZE_MASK;

		if (size == 0)
			break;

		if (i != 0) {
			/* tags may repeat... */
			if ((pa == firstpa && size == firstsize) ||
			    (pa == lastpa && size == lastsize))
				break;
		}

		/* Align base with size */
		base = (base + size - 1) & ~(size-1);

		/* reprogram the base address base address and enable */
		tag0 = (base & SPRAM_TAG0_PA_MASK) | SPRAM_TAG0_ENABLE;
		write(offset, tag0);

		base += size;

		/* reread the tag */
		tag0 = read(offset);
		pa = tag0 & SPRAM_TAG0_PA_MASK;
		enabled = tag0 & SPRAM_TAG0_ENABLE;

		if (i == 0) {
			firstpa = pa;
			firstsize = size;
		}

		lastpa = pa;
		lastsize = size;

		if (strcmp(type, "DSPRAM") == 0) {
			unsigned int *vp = (unsigned int *)(CKSEG1 | pa);
			unsigned int v;
#define TDAT	0x5a5aa5a5
			vp[0] = TDAT;
			vp[1] = ~TDAT;

			mb();

			v = vp[0];
			if (v != TDAT)
				printk(KERN_ERR "vp=%p wrote=%08x got=%08x\n",
				       vp, TDAT, v);
			v = vp[1];
			if (v != ~TDAT)
				printk(KERN_ERR "vp=%p wrote=%08x got=%08x\n",
				       vp+1, ~TDAT, v);
		}

		pr_info("%s%d: PA=%08x,Size=%08x%s\n",
			type, i, pa, size, enabled ? ",enabled" : "");
		offset += 2 * SPRAM_TAG_STRIDE;
	}
}
void spram_config(void)
{
	unsigned int config0;

	switch (current_cpu_type()) {
	case CPU_24K:
	case CPU_34K:
	case CPU_74K:
	case CPU_1004K:
	case CPU_1074K:
	case CPU_INTERAPTIV:
	case CPU_PROAPTIV:
	case CPU_P5600:
	case CPU_QEMU_GENERIC:
	case CPU_I6400:
		config0 = read_c0_config();
		/* FIXME: addresses are Malta specific */
		if (config0 & (1<<24)) {
			probe_spram("ISPRAM", 0x1c000000,
				    &ispram_load_tag, &ispram_store_tag);
		}
		if (config0 & (1<<23))
			probe_spram("DSPRAM", 0x1c100000,
				    &dspram_load_tag, &dspram_store_tag);
	}
}