arch/i386/kernel/cpu/cyrix.c

   1 #include <linux/init.h>
   2 #include <linux/bitops.h>
   3 #include <linux/delay.h>
   4 #include <linux/pci.h>
   5 #include <asm/dma.h>
   6 #include <asm/io.h>
   7 #include <asm/processor-cyrix.h>
   8 #include <asm/timer.h>
   9 #include <asm/pci-direct.h>
  10 #include <asm/tsc.h>
  11
  12 #include "cpu.h"
  13
  14 /*
  15  * Read NSC/Cyrix DEVID registers (DIR) to get more detailed info. about the CPU
  16  */
  17 static void __cpuinit do_cyrix_devid(unsigned char *dir0, unsigned char *dir1)
  18 {
  19         unsigned char ccr2, ccr3;
  20         unsigned long flags;
  21
  22         /* we test for DEVID by checking whether CCR3 is writable */
  23         local_irq_save(flags);
  24         ccr3 = getCx86(CX86_CCR3);
  25         setCx86(CX86_CCR3, ccr3 ^ 0x80);
  26         getCx86(0xc0);   /* dummy to change bus */
  27
  28         if (getCx86(CX86_CCR3) == ccr3) {       /* no DEVID regs. */
  29                 ccr2 = getCx86(CX86_CCR2);
  30                 setCx86(CX86_CCR2, ccr2 ^ 0x04);
  31                 getCx86(0xc0);  /* dummy */
  32
  33                 if (getCx86(CX86_CCR2) == ccr2) /* old Cx486SLC/DLC */
  34                         *dir0 = 0xfd;
  35                 else {                          /* Cx486S A step */
  36                         setCx86(CX86_CCR2, ccr2);
  37                         *dir0 = 0xfe;
  38                 }
  39         }
  40         else {
  41                 setCx86(CX86_CCR3, ccr3);  /* restore CCR3 */
  42
  43                 /* read DIR0 and DIR1 CPU registers */
  44                 *dir0 = getCx86(CX86_DIR0);
  45                 *dir1 = getCx86(CX86_DIR1);
  46         }
  47         local_irq_restore(flags);
  48 }
  49
  50 /*
  51  * Cx86_dir0_msb is a HACK needed by check_cx686_cpuid/slop in bugs.h in
  52  * order to identify the Cyrix CPU model after we're out of setup.c
  53  *
  54  * Actually since bugs.h doesn't even reference this perhaps someone should
  55  * fix the documentation ???
  56  */
  57 static unsigned char Cx86_dir0_msb __cpuinitdata = 0;
  58
  59 static char Cx86_model[][9] __cpuinitdata = {
  60         "Cx486", "Cx486", "5x86 ", "6x86", "MediaGX ", "6x86MX ",
  61         "M II ", "Unknown"
  62 };
  63 static char Cx486_name[][5] __cpuinitdata = {
  64         "SLC", "DLC", "SLC2", "DLC2", "SRx", "DRx",
  65         "SRx2", "DRx2"
  66 };
  67 static char Cx486S_name[][4] __cpuinitdata = {
  68         "S", "S2", "Se", "S2e"
  69 };
  70 static char Cx486D_name[][4] __cpuinitdata = {
  71         "DX", "DX2", "?", "?", "?", "DX4"
  72 };
  73 static char Cx86_cb[] __cpuinitdata = "?.5x Core/Bus Clock";
  74 static char cyrix_model_mult1[] __cpuinitdata = "12??43";
  75 static char cyrix_model_mult2[] __cpuinitdata = "12233445";
  76
  77 /*
  78  * Reset the slow-loop (SLOP) bit on the 686(L) which is set by some old
  79  * BIOSes for compatibility with DOS games.  This makes the udelay loop
  80  * work correctly, and improves performance.
  81  *
  82  * FIXME: our newer udelay uses the tsc. We don't need to frob with SLOP
  83  */
  84
  85 extern void calibrate_delay(void) __init;
  86
  87 static void __cpuinit check_cx686_slop(struct cpuinfo_x86 *c)
  88 {
  89         unsigned long flags;
  90
  91         if (Cx86_dir0_msb == 3) {
  92                 unsigned char ccr3, ccr5;
  93
  94                 local_irq_save(flags);
  95                 ccr3 = getCx86(CX86_CCR3);
  96                 setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10); /* enable MAPEN  */
  97                 ccr5 = getCx86(CX86_CCR5);
  98                 if (ccr5 & 2)
  99                         setCx86(CX86_CCR5, ccr5 & 0xfd);  /* reset SLOP */
 100                 setCx86(CX86_CCR3, ccr3);                 /* disable MAPEN */
 101                 local_irq_restore(flags);
 102
 103                 if (ccr5 & 2) { /* possible wrong calibration done */
 104                         printk(KERN_INFO "Recalibrating delay loop with SLOP bit reset\n");
 105                         calibrate_delay();
 106                         c->loops_per_jiffy = loops_per_jiffy;
 107                 }
 108         }
 109 }
 110
 111
 112 static void __cpuinit set_cx86_reorder(void)
 113 {
 114         u8 ccr3;
 115
 116         printk(KERN_INFO "Enable Memory access reorder on Cyrix/NSC processor.\n");
 117         ccr3 = getCx86(CX86_CCR3);
 118         setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10); /* enable MAPEN  */
 119
 120         /* Load/Store Serialize to mem access disable (=reorder it)  */
 121         setCx86(CX86_PCR0, getCx86(CX86_PCR0) & ~0x80);
 122         /* set load/store serialize from 1GB to 4GB */
 123         ccr3 |= 0xe0;
 124         setCx86(CX86_CCR3, ccr3);
 125 }
 126
 127 static void __cpuinit set_cx86_memwb(void)
 128 {
 129         u32 cr0;
 130
 131         printk(KERN_INFO "Enable Memory-Write-back mode on Cyrix/NSC processor.\n");
 132
 133         /* CCR2 bit 2: unlock NW bit */
 134         setCx86(CX86_CCR2, getCx86(CX86_CCR2) & ~0x04);
 135         /* set 'Not Write-through' */
 136         cr0 = 0x20000000;
 137         write_cr0(read_cr0() | cr0);
 138         /* CCR2 bit 2: lock NW bit and set WT1 */
 139         setCx86(CX86_CCR2, getCx86(CX86_CCR2) | 0x14 );
 140 }
 141
 142 static void __cpuinit set_cx86_inc(void)
 143 {
 144         unsigned char ccr3;
 145
 146         printk(KERN_INFO "Enable Incrementor on Cyrix/NSC processor.\n");
 147
 148         ccr3 = getCx86(CX86_CCR3);
 149         setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10); /* enable MAPEN  */
 150         /* PCR1 -- Performance Control */
 151         /* Incrementor on, whatever that is */
 152         setCx86(CX86_PCR1, getCx86(CX86_PCR1) | 0x02);
 153         /* PCR0 -- Performance Control */
 154         /* Incrementor Margin 10 */
 155         setCx86(CX86_PCR0, getCx86(CX86_PCR0) | 0x04);
 156         setCx86(CX86_CCR3, ccr3);       /* disable MAPEN */
 157 }
 158
 159 /*
 160  *      Configure later MediaGX and/or Geode processor.
 161  */
 162
 163 static void __cpuinit geode_configure(void)
 164 {
 165         unsigned long flags;
 166         u8 ccr3;
 167         local_irq_save(flags);
 168
 169         /* Suspend on halt power saving and enable #SUSP pin */
 170         setCx86(CX86_CCR2, getCx86(CX86_CCR2) | 0x88);
 171
 172         ccr3 = getCx86(CX86_CCR3);
 173         setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10);       /* enable MAPEN */
 174
 175
 176         /* FPU fast, DTE cache, Mem bypass */
 177         setCx86(CX86_CCR4, getCx86(CX86_CCR4) | 0x38);
 178         setCx86(CX86_CCR3, ccr3);                       /* disable MAPEN */
 179
 180         set_cx86_memwb();
 181         set_cx86_reorder();
 182         set_cx86_inc();
 183
 184         local_irq_restore(flags);
 185 }
 186
 187
 188 static void __cpuinit init_cyrix(struct cpuinfo_x86 *c)
 189 {
 190         unsigned char dir0, dir0_msn, dir0_lsn, dir1 = 0;
 191         char *buf = c->x86_model_id;
 192         const char *p = NULL;
 193
 194         /* Bit 31 in normal CPUID used for nonstandard 3DNow ID;
 195            3DNow is IDd by bit 31 in extended CPUID (1*32+31) anyway */
 196         clear_bit(0*32+31, c->x86_capability);
 197
 198         /* Cyrix used bit 24 in extended (AMD) CPUID for Cyrix MMX extensions */
 199         if ( test_bit(1*32+24, c->x86_capability) ) {
 200                 clear_bit(1*32+24, c->x86_capability);
 201                 set_bit(X86_FEATURE_CXMMX, c->x86_capability);
 202         }
 203
 204         do_cyrix_devid(&dir0, &dir1);
 205
 206         check_cx686_slop(c);
 207
 208         Cx86_dir0_msb = dir0_msn = dir0 >> 4; /* identifies CPU "family"   */
 209         dir0_lsn = dir0 & 0xf;                /* model or clock multiplier */
 210
 211         /* common case step number/rev -- exceptions handled below */
 212         c->x86_model = (dir1 >> 4) + 1;
 213         c->x86_mask = dir1 & 0xf;
 214
 215         /* Now cook; the original recipe is by Channing Corn, from Cyrix.
 216          * We do the same thing for each generation: we work out
 217          * the model, multiplier and stepping.  Black magic included,
 218          * to make the silicon step/rev numbers match the printed ones.
 219          */
 220
 221         switch (dir0_msn) {
 222                 unsigned char tmp;
 223
 224         case 0: /* Cx486SLC/DLC/SRx/DRx */
 225                 p = Cx486_name[dir0_lsn & 7];
 226                 break;
 227
 228         case 1: /* Cx486S/DX/DX2/DX4 */
 229                 p = (dir0_lsn & 8) ? Cx486D_name[dir0_lsn & 5]
 230                         : Cx486S_name[dir0_lsn & 3];
 231                 break;
 232
 233         case 2: /* 5x86 */
 234                 Cx86_cb[2] = cyrix_model_mult1[dir0_lsn & 5];
 235                 p = Cx86_cb+2;
 236                 break;
 237
 238         case 3: /* 6x86/6x86L */
 239                 Cx86_cb[1] = ' ';
 240                 Cx86_cb[2] = cyrix_model_mult1[dir0_lsn & 5];
 241                 if (dir1 > 0x21) { /* 686L */
 242                         Cx86_cb[0] = 'L';
 243                         p = Cx86_cb;
 244                         (c->x86_model)++;
 245                 } else             /* 686 */
 246                         p = Cx86_cb+1;
 247                 /* Emulate MTRRs using Cyrix's ARRs. */
 248                 set_bit(X86_FEATURE_CYRIX_ARR, c->x86_capability);
 249                 /* 6x86's contain this bug */
 250                 c->coma_bug = 1;
 251                 break;
 252
 253         case 4: /* MediaGX/GXm or Geode GXM/GXLV/GX1 */
 254 #ifdef CONFIG_PCI
 255         {
 256                 u32 vendor, device;
 257                 /* It isn't really a PCI quirk directly, but the cure is the
 258                    same. The MediaGX has deep magic SMM stuff that handles the
 259                    SB emulation. It thows away the fifo on disable_dma() which
 260                    is wrong and ruins the audio.
 261
 262                    Bug2: VSA1 has a wrap bug so that using maximum sized DMA
 263                    causes bad things. According to NatSemi VSA2 has another
 264                    bug to do with 'hlt'. I've not seen any boards using VSA2
 265                    and X doesn't seem to support it either so who cares 8).
 266                    VSA1 we work around however.
 267                 */
 268
 269                 printk(KERN_INFO "Working around Cyrix MediaGX virtual DMA bugs.\n");
 270                 isa_dma_bridge_buggy = 2;
 271
 272                 /* We do this before the PCI layer is running. However we
 273                    are safe here as we know the bridge must be a Cyrix
 274                    companion and must be present */
 275                 vendor = read_pci_config_16(0, 0, 0x12, PCI_VENDOR_ID);
 276                 device = read_pci_config_16(0, 0, 0x12, PCI_DEVICE_ID);
 277
 278                 /*
 279                  *  The 5510/5520 companion chips have a funky PIT.
 280                  */
 281                 if (vendor == PCI_VENDOR_ID_CYRIX &&
 282          (device == PCI_DEVICE_ID_CYRIX_5510 || device == PCI_DEVICE_ID_CYRIX_5520))
 283                         mark_tsc_unstable("cyrix 5510/5520 detected");
 284         }
 285 #endif
 286                 c->x86_cache_size=16;   /* Yep 16K integrated cache thats it */
 287
 288                 /* GXm supports extended cpuid levels 'ala' AMD */
 289                 if (c->cpuid_level == 2) {
 290                         /* Enable cxMMX extensions (GX1 Datasheet 54) */
 291                         setCx86(CX86_CCR7, getCx86(CX86_CCR7) | 1);
 292
 293                         /*
 294                          * GXm : 0x30 ... 0x5f GXm  datasheet 51
 295                          * GXlv: 0x6x          GXlv datasheet 54
 296                          *  ?  : 0x7x
 297                          * GX1 : 0x8x          GX1  datasheet 56
 298                          */
 299                         if((0x30 <= dir1 && dir1 <= 0x6f) || (0x80 <=dir1 && dir1 <= 0x8f))
 300                                 geode_configure();
 301                         get_model_name(c);  /* get CPU marketing name */
 302                         return;
 303                 }
 304                 else {  /* MediaGX */
 305                         Cx86_cb[2] = (dir0_lsn & 1) ? '3' : '4';
 306                         p = Cx86_cb+2;
 307                         c->x86_model = (dir1 & 0x20) ? 1 : 2;
 308                 }
 309                 break;
 310
 311         case 5: /* 6x86MX/M II */
 312                 if (dir1 > 7)
 313                 {
 314                         dir0_msn++;  /* M II */
 315                         /* Enable MMX extensions (App note 108) */
 316                         setCx86(CX86_CCR7, getCx86(CX86_CCR7)|1);
 317                 }
 318                 else
 319                 {
 320                         c->coma_bug = 1;      /* 6x86MX, it has the bug. */
 321                 }
 322                 tmp = (!(dir0_lsn & 7) || dir0_lsn & 1) ? 2 : 0;
 323                 Cx86_cb[tmp] = cyrix_model_mult2[dir0_lsn & 7];
 324                 p = Cx86_cb+tmp;
 325                 if (((dir1 & 0x0f) > 4) || ((dir1 & 0xf0) == 0x20))
 326                         (c->x86_model)++;
 327                 /* Emulate MTRRs using Cyrix's ARRs. */
 328                 set_bit(X86_FEATURE_CYRIX_ARR, c->x86_capability);
 329                 break;
 330
 331         case 0xf:  /* Cyrix 486 without DEVID registers */
 332                 switch (dir0_lsn) {
 333                 case 0xd:  /* either a 486SLC or DLC w/o DEVID */
 334                         dir0_msn = 0;
 335                         p = Cx486_name[(c->hard_math) ? 1 : 0];
 336                         break;
 337
 338                 case 0xe:  /* a 486S A step */
 339                         dir0_msn = 0;
 340                         p = Cx486S_name[0];
 341                         break;
 342                 }
 343                 break;
 344
 345         default:  /* unknown (shouldn't happen, we know everyone ;-) */
 346                 dir0_msn = 7;
 347                 break;
 348         }
 349         strcpy(buf, Cx86_model[dir0_msn & 7]);
 350         if (p) strcat(buf, p);
 351         return;
 352 }
 353
 354 /*
 355  * Handle National Semiconductor branded processors
 356  */
 357 static void __cpuinit init_nsc(struct cpuinfo_x86 *c)
 358 {
 359         /* There may be GX1 processors in the wild that are branded
 360          * NSC and not Cyrix.
 361          *
 362          * This function only handles the GX processor, and kicks every
 363          * thing else to the Cyrix init function above - that should
 364          * cover any processors that might have been branded differently
 365          * after NSC acquired Cyrix.
 366          *
 367          * If this breaks your GX1 horribly, please e-mail
 368          * info-linux@ldcmail.amd.com to tell us.
 369          */
 370
 371         /* Handle the GX (Formally known as the GX2) */
 372
 373         if (c->x86 == 5 && c->x86_model == 5)
 374                 display_cacheinfo(c);
 375         else
 376                 init_cyrix(c);
 377 }
 378
 379 /*
 380  * Cyrix CPUs without cpuid or with cpuid not yet enabled can be detected
 381  * by the fact that they preserve the flags across the division of 5/2.
 382  * PII and PPro exhibit this behavior too, but they have cpuid available.
 383  */
 384
 385 /*
 386  * Perform the Cyrix 5/2 test. A Cyrix won't change
 387  * the flags, while other 486 chips will.
 388  */
 389 static inline int test_cyrix_52div(void)
 390 {
 391         unsigned int test;
 392
 393         __asm__ __volatile__(
 394              "sahf\n\t"         /* clear flags (%eax = 0x0005) */
 395              "div %b2\n\t"      /* divide 5 by 2 */
 396              "lahf"             /* store flags into %ah */
 397              : "=a" (test)
 398              : "0" (5), "q" (2)
 399              : "cc");
 400
 401         /* AH is 0x02 on Cyrix after the divide.. */
 402         return (unsigned char) (test >> 8) == 0x02;
 403 }
 404
 405 static void __cpuinit cyrix_identify(struct cpuinfo_x86 * c)
 406 {
 407         /* Detect Cyrix with disabled CPUID */
 408         if ( c->x86 == 4 && test_cyrix_52div() ) {
 409                 unsigned char dir0, dir1;
 410
 411                 strcpy(c->x86_vendor_id, "CyrixInstead");
 412                 c->x86_vendor = X86_VENDOR_CYRIX;
 413
 414                 /* Actually enable cpuid on the older cyrix */
 415
 416                 /* Retrieve CPU revisions */
 417
 418                 do_cyrix_devid(&dir0, &dir1);
 419
 420                 dir0>>=4;
 421
 422                 /* Check it is an affected model */
 423
 424                 if (dir0 == 5 || dir0 == 3)
 425                 {
 426                         unsigned char ccr3;
 427                         unsigned long flags;
 428                         printk(KERN_INFO "Enabling CPUID on Cyrix processor.\n");
 429                         local_irq_save(flags);
 430                         ccr3 = getCx86(CX86_CCR3);
 431                         setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10);       /* enable MAPEN  */
 432                         setCx86(CX86_CCR4, getCx86(CX86_CCR4) | 0x80);  /* enable cpuid  */
 433                         setCx86(CX86_CCR3, ccr3);                       /* disable MAPEN */
 434                         local_irq_restore(flags);
 435                 }
 436         }
 437 }
 438
 439 static struct cpu_dev cyrix_cpu_dev __cpuinitdata = {
 440         .c_vendor       = "Cyrix",
 441         .c_ident        = { "CyrixInstead" },
 442         .c_init         = init_cyrix,
 443         .c_identify     = cyrix_identify,
 444 };
 445
 446 int __init cyrix_init_cpu(void)
 447 {
 448         cpu_devs[X86_VENDOR_CYRIX] = &cyrix_cpu_dev;
 449         return 0;
 450 }
 451
 452 static struct cpu_dev nsc_cpu_dev __cpuinitdata = {
 453         .c_vendor       = "NSC",
 454         .c_ident        = { "Geode by NSC" },
 455         .c_init         = init_nsc,
 456 };
 457
 458 int __init nsc_init_cpu(void)
 459 {
 460         cpu_devs[X86_VENDOR_NSC] = &nsc_cpu_dev;
 461         return 0;
 462 }
 463