arch/x86/kernel/cpu/mtrr/cyrix.c

   1 #include <linux/init.h>
   2 #include <linux/io.h>
   3 #include <linux/mm.h>
   4
   5 #include <asm/processor-cyrix.h>
   6 #include <asm/processor-flags.h>
   7 #include <asm/mtrr.h>
   8 #include <asm/msr.h>
   9
  10 #include "mtrr.h"
  11
  12 static void
  13 cyrix_get_arr(unsigned int reg, unsigned long *base,
  14               unsigned long *size, mtrr_type * type)
  15 {
  16         unsigned char arr, ccr3, rcr, shift;
  17         unsigned long flags;
  18
  19         arr = CX86_ARR_BASE + (reg << 1) + reg; /* avoid multiplication by 3 */
  20
  21         local_irq_save(flags);
  22
  23         ccr3 = getCx86(CX86_CCR3);
  24         setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10);       /* enable MAPEN */
  25         ((unsigned char *)base)[3] = getCx86(arr);
  26         ((unsigned char *)base)[2] = getCx86(arr + 1);
  27         ((unsigned char *)base)[1] = getCx86(arr + 2);
  28         rcr = getCx86(CX86_RCR_BASE + reg);
  29         setCx86(CX86_CCR3, ccr3);                       /* disable MAPEN */
  30
  31         local_irq_restore(flags);
  32
  33         shift = ((unsigned char *) base)[1] & 0x0f;
  34         *base >>= PAGE_SHIFT;
  35
  36         /*
  37          * Power of two, at least 4K on ARR0-ARR6, 256K on ARR7
  38          * Note: shift==0xf means 4G, this is unsupported.
  39          */
  40         if (shift)
  41                 *size = (reg < 7 ? 0x1UL : 0x40UL) << (shift - 1);
  42         else
  43                 *size = 0;
  44
  45         /* Bit 0 is Cache Enable on ARR7, Cache Disable on ARR0-ARR6 */
  46         if (reg < 7) {
  47                 switch (rcr) {
  48                 case 1:
  49                         *type = MTRR_TYPE_UNCACHABLE;
  50                         break;
  51                 case 8:
  52                         *type = MTRR_TYPE_WRBACK;
  53                         break;
  54                 case 9:
  55                         *type = MTRR_TYPE_WRCOMB;
  56                         break;
  57                 case 24:
  58                 default:
  59                         *type = MTRR_TYPE_WRTHROUGH;
  60                         break;
  61                 }
  62         } else {
  63                 switch (rcr) {
  64                 case 0:
  65                         *type = MTRR_TYPE_UNCACHABLE;
  66                         break;
  67                 case 8:
  68                         *type = MTRR_TYPE_WRCOMB;
  69                         break;
  70                 case 9:
  71                         *type = MTRR_TYPE_WRBACK;
  72                         break;
  73                 case 25:
  74                 default:
  75                         *type = MTRR_TYPE_WRTHROUGH;
  76                         break;
  77                 }
  78         }
  79 }
  80
  81 /*
  82  * cyrix_get_free_region - get a free ARR.
  83  *
  84  * @base: the starting (base) address of the region.
  85  * @size: the size (in bytes) of the region.
  86  *
  87  * Returns: the index of the region on success, else -1 on error.
  88 */
  89 static int
  90 cyrix_get_free_region(unsigned long base, unsigned long size, int replace_reg)
  91 {
  92         unsigned long lbase, lsize;
  93         mtrr_type ltype;
  94         int i;
  95
  96         switch (replace_reg) {
  97         case 7:
  98                 if (size < 0x40)
  99                         break;
 100         case 6:
 101         case 5:
 102         case 4:
 103                 return replace_reg;
 104         case 3:
 105         case 2:
 106         case 1:
 107         case 0:
 108                 return replace_reg;
 109         }
 110         /* If we are to set up a region >32M then look at ARR7 immediately */
 111         if (size > 0x2000) {
 112                 cyrix_get_arr(7, &lbase, &lsize, &ltype);
 113                 if (lsize == 0)
 114                         return 7;
 115                 /* Else try ARR0-ARR6 first  */
 116         } else {
 117                 for (i = 0; i < 7; i++) {
 118                         cyrix_get_arr(i, &lbase, &lsize, &ltype);
 119                         if (lsize == 0)
 120                                 return i;
 121                 }
 122                 /*
 123                  * ARR0-ARR6 isn't free
 124                  * try ARR7 but its size must be at least 256K
 125                  */
 126                 cyrix_get_arr(i, &lbase, &lsize, &ltype);
 127                 if ((lsize == 0) && (size >= 0x40))
 128                         return i;
 129         }
 130         return -ENOSPC;
 131 }
 132
 133 static u32 cr4, ccr3;
 134
 135 static void prepare_set(void)
 136 {
 137         u32 cr0;
 138
 139         /*  Save value of CR4 and clear Page Global Enable (bit 7)  */
 140         if (cpu_has_pge) {
 141                 cr4 = read_cr4();
 142                 write_cr4(cr4 & ~X86_CR4_PGE);
 143         }
 144
 145         /*
 146          * Disable and flush caches.
 147          * Note that wbinvd flushes the TLBs as a side-effect
 148          */
 149         cr0 = read_cr0() | X86_CR0_CD;
 150         wbinvd();
 151         write_cr0(cr0);
 152         wbinvd();
 153
 154         /* Cyrix ARRs - everything else was excluded at the top */
 155         ccr3 = getCx86(CX86_CCR3);
 156
 157         /* Cyrix ARRs - everything else was excluded at the top */
 158         setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10);
 159 }
 160
 161 static void post_set(void)
 162 {
 163         /* Flush caches and TLBs */
 164         wbinvd();
 165
 166         /* Cyrix ARRs - everything else was excluded at the top */
 167         setCx86(CX86_CCR3, ccr3);
 168
 169         /* Enable caches */
 170         write_cr0(read_cr0() & 0xbfffffff);
 171
 172         /* Restore value of CR4 */
 173         if (cpu_has_pge)
 174                 write_cr4(cr4);
 175 }
 176
 177 static void cyrix_set_arr(unsigned int reg, unsigned long base,
 178                           unsigned long size, mtrr_type type)
 179 {
 180         unsigned char arr, arr_type, arr_size;
 181
 182         arr = CX86_ARR_BASE + (reg << 1) + reg; /* avoid multiplication by 3 */
 183
 184         /* count down from 32M (ARR0-ARR6) or from 2G (ARR7) */
 185         if (reg >= 7)
 186                 size >>= 6;
 187
 188         size &= 0x7fff;         /* make sure arr_size <= 14 */
 189         for (arr_size = 0; size; arr_size++, size >>= 1)
 190                 ;
 191
 192         if (reg < 7) {
 193                 switch (type) {
 194                 case MTRR_TYPE_UNCACHABLE:
 195                         arr_type = 1;
 196                         break;
 197                 case MTRR_TYPE_WRCOMB:
 198                         arr_type = 9;
 199                         break;
 200                 case MTRR_TYPE_WRTHROUGH:
 201                         arr_type = 24;
 202                         break;
 203                 default:
 204                         arr_type = 8;
 205                         break;
 206                 }
 207         } else {
 208                 switch (type) {
 209                 case MTRR_TYPE_UNCACHABLE:
 210                         arr_type = 0;
 211                         break;
 212                 case MTRR_TYPE_WRCOMB:
 213                         arr_type = 8;
 214                         break;
 215                 case MTRR_TYPE_WRTHROUGH:
 216                         arr_type = 25;
 217                         break;
 218                 default:
 219                         arr_type = 9;
 220                         break;
 221                 }
 222         }
 223
 224         prepare_set();
 225
 226         base <<= PAGE_SHIFT;
 227         setCx86(arr + 0,  ((unsigned char *)&base)[3]);
 228         setCx86(arr + 1,  ((unsigned char *)&base)[2]);
 229         setCx86(arr + 2, (((unsigned char *)&base)[1]) | arr_size);
 230         setCx86(CX86_RCR_BASE + reg, arr_type);
 231
 232         post_set();
 233 }
 234
 235 typedef struct {
 236         unsigned long   base;
 237         unsigned long   size;
 238         mtrr_type       type;
 239 } arr_state_t;
 240
 241 static arr_state_t arr_state[8] = {
 242         {0UL, 0UL, 0UL}, {0UL, 0UL, 0UL}, {0UL, 0UL, 0UL}, {0UL, 0UL, 0UL},
 243         {0UL, 0UL, 0UL}, {0UL, 0UL, 0UL}, {0UL, 0UL, 0UL}, {0UL, 0UL, 0UL}
 244 };
 245
 246 static unsigned char ccr_state[7] = { 0, 0, 0, 0, 0, 0, 0 };
 247
 248 static void cyrix_set_all(void)
 249 {
 250         int i;
 251
 252         prepare_set();
 253
 254         /* the CCRs are not contiguous */
 255         for (i = 0; i < 4; i++)
 256                 setCx86(CX86_CCR0 + i, ccr_state[i]);
 257         for (; i < 7; i++)
 258                 setCx86(CX86_CCR4 + i, ccr_state[i]);
 259
 260         for (i = 0; i < 8; i++) {
 261                 cyrix_set_arr(i, arr_state[i].base,
 262                               arr_state[i].size, arr_state[i].type);
 263         }
 264
 265         post_set();
 266 }
 267
 268 static const struct mtrr_ops cyrix_mtrr_ops = {
 269         .vendor            = X86_VENDOR_CYRIX,
 270         .set_all           = cyrix_set_all,
 271         .set               = cyrix_set_arr,
 272         .get               = cyrix_get_arr,
 273         .get_free_region   = cyrix_get_free_region,
 274         .validate_add_page = generic_validate_add_page,
 275         .have_wrcomb       = positive_have_wrcomb,
 276 };
 277
 278 int __init cyrix_init_mtrr(void)
 279 {
 280         set_mtrr_ops(&cyrix_mtrr_ops);
 281         return 0;
 282 }