1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * MIPS SPRAM support
4 *
5 * Copyright (C) 2007, 2008 MIPS Technologies, Inc.
6 */
7 #include <linux/kernel.h>
8 #include <linux/ptrace.h>
9 #include <linux/stddef.h>
10
11 #include <asm/fpu.h>
12 #include <asm/mipsregs.h>
13 #include <asm/r4kcache.h>
14 #include <asm/hazards.h>
15 #include <asm/spram.h>
16
17 /*
18 * These definitions are correct for the 24K/34K/74K SPRAM sample
19 * implementation. The 4KS interpreted the tags differently...
20 */
21 #define SPRAM_TAG0_ENABLE 0x00000080
22 #define SPRAM_TAG0_PA_MASK 0xfffff000
23 #define SPRAM_TAG1_SIZE_MASK 0xfffff000
24
25 #define SPRAM_TAG_STRIDE 8
26
27 #define ERRCTL_SPRAM (1 << 28)
28
29 /* errctl access */
30 #define read_c0_errctl(x) read_c0_ecc(x)
31 #define write_c0_errctl(x) write_c0_ecc(x)
32
33 /*
34 * Different semantics to the set_c0_* function built by __BUILD_SET_C0
35 */
36 static unsigned int bis_c0_errctl(unsigned int set)
37 {
38 unsigned int res;
39 res = read_c0_errctl();
40 write_c0_errctl(res | set);
41 return res;
42 }
43
44 static void ispram_store_tag(unsigned int offset, unsigned int data)
45 {
46 unsigned int errctl;
47
48 /* enable SPRAM tag access */
49 errctl = bis_c0_errctl(ERRCTL_SPRAM);
50 ehb();
51
52 write_c0_taglo(data);
53 ehb();
54
55 cache_op(Index_Store_Tag_I, CKSEG0|offset);
56 ehb();
57
58 write_c0_errctl(errctl);
59 ehb();
60 }
61
62
63 static unsigned int ispram_load_tag(unsigned int offset)
64 {
65 unsigned int data;
66 unsigned int errctl;
67
68 /* enable SPRAM tag access */
69 errctl = bis_c0_errctl(ERRCTL_SPRAM);
70 ehb();
71 cache_op(Index_Load_Tag_I, CKSEG0 | offset);
72 ehb();
73 data = read_c0_taglo();
74 ehb();
75 write_c0_errctl(errctl);
76 ehb();
77
78 return data;
79 }
80
81 static void dspram_store_tag(unsigned int offset, unsigned int data)
82 {
83 unsigned int errctl;
84
85 /* enable SPRAM tag access */
86 errctl = bis_c0_errctl(ERRCTL_SPRAM);
87 ehb();
88 write_c0_dtaglo(data);
89 ehb();
90 cache_op(Index_Store_Tag_D, CKSEG0 | offset);
91 ehb();
92 write_c0_errctl(errctl);
93 ehb();
94 }
95
96
97 static unsigned int dspram_load_tag(unsigned int offset)
98 {
99 unsigned int data;
100 unsigned int errctl;
101
102 errctl = bis_c0_errctl(ERRCTL_SPRAM);
103 ehb();
104 cache_op(Index_Load_Tag_D, CKSEG0 | offset);
105 ehb();
106 data = read_c0_dtaglo();
107 ehb();
108 write_c0_errctl(errctl);
109 ehb();
110
111 return data;
112 }
113
114 static void probe_spram(char *type,
115 unsigned int base,
116 unsigned int (*read)(unsigned int),
117 void (*write)(unsigned int, unsigned int))
118 {
119 unsigned int firstsize = 0, lastsize = 0;
120 unsigned int firstpa = 0, lastpa = 0, pa = 0;
121 unsigned int offset = 0;
122 unsigned int size, tag0, tag1;
123 unsigned int enabled;
124 int i;
125
126 /*
127 * The limit is arbitrary but avoids the loop running away if
128 * the SPRAM tags are implemented differently
129 */
130
131 for (i = 0; i < 8; i++) {
132 tag0 = read(offset);
133 tag1 = read(offset+SPRAM_TAG_STRIDE);
134 pr_debug("DBG %s%d: tag0=%08x tag1=%08x\n",
135 type, i, tag0, tag1);
136
137 size = tag1 & SPRAM_TAG1_SIZE_MASK;
138
139 if (size == 0)
140 break;
141
142 if (i != 0) {
143 /* tags may repeat... */
144 if ((pa == firstpa && size == firstsize) ||
145 (pa == lastpa && size == lastsize))
146 break;
147 }
148
149 /* Align base with size */
150 base = (base + size - 1) & ~(size-1);
151
152 /* reprogram the base address base address and enable */
153 tag0 = (base & SPRAM_TAG0_PA_MASK) | SPRAM_TAG0_ENABLE;
154 write(offset, tag0);
155
156 base += size;
157
158 /* reread the tag */
159 tag0 = read(offset);
160 pa = tag0 & SPRAM_TAG0_PA_MASK;
161 enabled = tag0 & SPRAM_TAG0_ENABLE;
162
163 if (i == 0) {
164 firstpa = pa;
165 firstsize = size;
166 }
167
168 lastpa = pa;
169 lastsize = size;
170
171 if (strcmp(type, "DSPRAM") == 0) {
172 unsigned int *vp = (unsigned int *)(CKSEG1 | pa);
173 unsigned int v;
174 #define TDAT 0x5a5aa5a5
175 vp[0] = TDAT;
176 vp[1] = ~TDAT;
177
178 mb();
179
180 v = vp[0];
181 if (v != TDAT)
182 printk(KERN_ERR "vp=%p wrote=%08x got=%08x\n",
183 vp, TDAT, v);
184 v = vp[1];
185 if (v != ~TDAT)
186 printk(KERN_ERR "vp=%p wrote=%08x got=%08x\n",
187 vp+1, ~TDAT, v);
188 }
189
190 pr_info("%s%d: PA=%08x,Size=%08x%s\n",
191 type, i, pa, size, enabled ? ",enabled" : "");
192 offset += 2 * SPRAM_TAG_STRIDE;
193 }
194 }
195 void spram_config(void)
196 {
197 unsigned int config0;
198
199 switch (current_cpu_type()) {
200 case CPU_24K:
201 case CPU_34K:
202 case CPU_74K:
203 case CPU_1004K:
204 case CPU_1074K:
205 case CPU_INTERAPTIV:
206 case CPU_PROAPTIV:
207 case CPU_P5600:
208 case CPU_QEMU_GENERIC:
209 case CPU_I6400:
210 case CPU_P6600:
211 config0 = read_c0_config();
212 /* FIXME: addresses are Malta specific */
213 if (config0 & MIPS_CONF_ISP) {
214 probe_spram("ISPRAM", 0x1c000000,
215 &ispram_load_tag, &ispram_store_tag);
216 }
217 if (config0 & MIPS_CONF_DSP)
218 probe_spram("DSPRAM", 0x1c100000,
219 &dspram_load_tag, &dspram_store_tag);
220 }
221 }
222
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.