arch/mips/kernel/spram.c

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