arch/i386/kernel/cpu/centaur.c

   1 #include <linux/kernel.h>
   2 #include <linux/init.h>
   3 #include <linux/bitops.h>
   4 #include <asm/processor.h>
   5 #include <asm/msr.h>
   6 #include <asm/e820.h>
   7 #include "cpu.h"
   8
   9 #ifdef CONFIG_X86_OOSTORE
  10
  11 static u32 __init power2(u32 x)
  12 {
  13         u32 s=1;
  14         while(s<=x)
  15                 s<<=1;
  16         return s>>=1;
  17 }
  18
  19
  20 /*
  21  *      Set up an actual MCR
  22  */
  23
  24 static void __init centaur_mcr_insert(int reg, u32 base, u32 size, int key)
  25 {
  26         u32 lo, hi;
  27
  28         hi = base & ~0xFFF;
  29         lo = ~(size-1);         /* Size is a power of 2 so this makes a mask */
  30         lo &= ~0xFFF;           /* Remove the ctrl value bits */
  31         lo |= key;              /* Attribute we wish to set */
  32         wrmsr(reg+MSR_IDT_MCR0, lo, hi);
  33         mtrr_centaur_report_mcr(reg, lo, hi);   /* Tell the mtrr driver */
  34 }
  35
  36 /*
  37  *      Figure what we can cover with MCR's
  38  *
  39  *      Shortcut: We know you can't put 4Gig of RAM on a winchip
  40  */
  41
  42 static u32 __init ramtop(void)          /* 16388 */
  43 {
  44         int i;
  45         u32 top = 0;
  46         u32 clip = 0xFFFFFFFFUL;
  47
  48         for (i = 0; i < e820.nr_map; i++) {
  49                 unsigned long start, end;
  50
  51                 if (e820.map[i].addr > 0xFFFFFFFFUL)
  52                         continue;
  53                 /*
  54                  *      Don't MCR over reserved space. Ignore the ISA hole
  55                  *      we frob around that catastrophy already
  56                  */
  57
  58                 if (e820.map[i].type == E820_RESERVED)
  59                 {
  60                         if(e820.map[i].addr >= 0x100000UL && e820.map[i].addr < clip)
  61                                 clip = e820.map[i].addr;
  62                         continue;
  63                 }
  64                 start = e820.map[i].addr;
  65                 end = e820.map[i].addr + e820.map[i].size;
  66                 if (start >= end)
  67                         continue;
  68                 if (end > top)
  69                         top = end;
  70         }
  71         /* Everything below 'top' should be RAM except for the ISA hole.
  72            Because of the limited MCR's we want to map NV/ACPI into our
  73            MCR range for gunk in RAM
  74
  75            Clip might cause us to MCR insufficient RAM but that is an
  76            acceptable failure mode and should only bite obscure boxes with
  77            a VESA hole at 15Mb
  78
  79            The second case Clip sometimes kicks in is when the EBDA is marked
  80            as reserved. Again we fail safe with reasonable results
  81         */
  82
  83         if(top>clip)
  84                 top=clip;
  85
  86         return top;
  87 }
  88
  89 /*
  90  *      Compute a set of MCR's to give maximum coverage
  91  */
  92
  93 static int __init centaur_mcr_compute(int nr, int key)
  94 {
  95         u32 mem = ramtop();
  96         u32 root = power2(mem);
  97         u32 base = root;
  98         u32 top = root;
  99         u32 floor = 0;
 100         int ct = 0;
 101
 102         while(ct<nr)
 103         {
 104                 u32 fspace = 0;
 105
 106                 /*
 107                  *      Find the largest block we will fill going upwards
 108                  */
 109
 110                 u32 high = power2(mem-top);
 111
 112                 /*
 113                  *      Find the largest block we will fill going downwards
 114                  */
 115
 116                 u32 low = base/2;
 117
 118                 /*
 119                  *      Don't fill below 1Mb going downwards as there
 120                  *      is an ISA hole in the way.
 121                  */
 122
 123                 if(base <= 1024*1024)
 124                         low = 0;
 125
 126                 /*
 127                  *      See how much space we could cover by filling below
 128                  *      the ISA hole
 129                  */
 130
 131                 if(floor == 0)
 132                         fspace = 512*1024;
 133                 else if(floor ==512*1024)
 134                         fspace = 128*1024;
 135
 136                 /* And forget ROM space */
 137
 138                 /*
 139                  *      Now install the largest coverage we get
 140                  */
 141
 142                 if(fspace > high && fspace > low)
 143                 {
 144                         centaur_mcr_insert(ct, floor, fspace, key);
 145                         floor += fspace;
 146                 }
 147                 else if(high > low)
 148                 {
 149                         centaur_mcr_insert(ct, top, high, key);
 150                         top += high;
 151                 }
 152                 else if(low > 0)
 153                 {
 154                         base -= low;
 155                         centaur_mcr_insert(ct, base, low, key);
 156                 }
 157                 else break;
 158                 ct++;
 159         }
 160         /*
 161          *      We loaded ct values. We now need to set the mask. The caller
 162          *      must do this bit.
 163          */
 164
 165         return ct;
 166 }
 167
 168 static void __init centaur_create_optimal_mcr(void)
 169 {
 170         int i;
 171         /*
 172          *      Allocate up to 6 mcrs to mark as much of ram as possible
 173          *      as write combining and weak write ordered.
 174          *
 175          *      To experiment with: Linux never uses stack operations for
 176          *      mmio spaces so we could globally enable stack operation wc
 177          *
 178          *      Load the registers with type 31 - full write combining, all
 179          *      writes weakly ordered.
 180          */
 181         int used = centaur_mcr_compute(6, 31);
 182
 183         /*
 184          *      Wipe unused MCRs
 185          */
 186
 187         for(i=used;i<8;i++)
 188                 wrmsr(MSR_IDT_MCR0+i, 0, 0);
 189 }
 190
 191 static void __init winchip2_create_optimal_mcr(void)
 192 {
 193         u32 lo, hi;
 194         int i;
 195
 196         /*
 197          *      Allocate up to 6 mcrs to mark as much of ram as possible
 198          *      as write combining, weak store ordered.
 199          *
 200          *      Load the registers with type 25
 201          *              8       -       weak write ordering
 202          *              16      -       weak read ordering
 203          *              1       -       write combining
 204          */
 205
 206         int used = centaur_mcr_compute(6, 25);
 207
 208         /*
 209          *      Mark the registers we are using.
 210          */
 211
 212         rdmsr(MSR_IDT_MCR_CTRL, lo, hi);
 213         for(i=0;i<used;i++)
 214                 lo|=1<<(9+i);
 215         wrmsr(MSR_IDT_MCR_CTRL, lo, hi);
 216
 217         /*
 218          *      Wipe unused MCRs
 219          */
 220
 221         for(i=used;i<8;i++)
 222                 wrmsr(MSR_IDT_MCR0+i, 0, 0);
 223 }
 224
 225 /*
 226  *      Handle the MCR key on the Winchip 2.
 227  */
 228
 229 static void __init winchip2_unprotect_mcr(void)
 230 {
 231         u32 lo, hi;
 232         u32 key;
 233
 234         rdmsr(MSR_IDT_MCR_CTRL, lo, hi);
 235         lo&=~0x1C0;     /* blank bits 8-6 */
 236         key = (lo>>17) & 7;
 237         lo |= key<<6;   /* replace with unlock key */
 238         wrmsr(MSR_IDT_MCR_CTRL, lo, hi);
 239 }
 240
 241 static void __init winchip2_protect_mcr(void)
 242 {
 243         u32 lo, hi;
 244
 245         rdmsr(MSR_IDT_MCR_CTRL, lo, hi);
 246         lo&=~0x1C0;     /* blank bits 8-6 */
 247         wrmsr(MSR_IDT_MCR_CTRL, lo, hi);
 248 }
 249 #endif /* CONFIG_X86_OOSTORE */
 250
 251 #define ACE_PRESENT     (1 << 6)
 252 #define ACE_ENABLED     (1 << 7)
 253 #define ACE_FCR         (1 << 28)       /* MSR_VIA_FCR */
 254
 255 #define RNG_PRESENT     (1 << 2)
 256 #define RNG_ENABLED     (1 << 3)
 257 #define RNG_ENABLE      (1 << 6)        /* MSR_VIA_RNG */
 258
 259 static void __init init_c3(struct cpuinfo_x86 *c)
 260 {
 261         u32  lo, hi;
 262
 263         /* Test for Centaur Extended Feature Flags presence */
 264         if (cpuid_eax(0xC0000000) >= 0xC0000001) {
 265                 u32 tmp = cpuid_edx(0xC0000001);
 266
 267                 /* enable ACE unit, if present and disabled */
 268                 if ((tmp & (ACE_PRESENT | ACE_ENABLED)) == ACE_PRESENT) {
 269                         rdmsr (MSR_VIA_FCR, lo, hi);
 270                         lo |= ACE_FCR;          /* enable ACE unit */
 271                         wrmsr (MSR_VIA_FCR, lo, hi);
 272                         printk(KERN_INFO "CPU: Enabled ACE h/w crypto\n");
 273                 }
 274
 275                 /* enable RNG unit, if present and disabled */
 276                 if ((tmp & (RNG_PRESENT | RNG_ENABLED)) == RNG_PRESENT) {
 277                         rdmsr (MSR_VIA_RNG, lo, hi);
 278                         lo |= RNG_ENABLE;       /* enable RNG unit */
 279                         wrmsr (MSR_VIA_RNG, lo, hi);
 280                         printk(KERN_INFO "CPU: Enabled h/w RNG\n");
 281                 }
 282
 283                 /* store Centaur Extended Feature Flags as
 284                  * word 5 of the CPU capability bit array
 285                  */
 286                 c->x86_capability[5] = cpuid_edx(0xC0000001);
 287         }
 288
 289         /* Cyrix III family needs CX8 & PGE explicity enabled. */
 290         if (c->x86_model >=6 && c->x86_model <= 9) {
 291                 rdmsr (MSR_VIA_FCR, lo, hi);
 292                 lo |= (1<<1 | 1<<7);
 293                 wrmsr (MSR_VIA_FCR, lo, hi);
 294                 set_bit(X86_FEATURE_CX8, c->x86_capability);
 295         }
 296
 297         /* Before Nehemiah, the C3's had 3dNOW! */
 298         if (c->x86_model >=6 && c->x86_model <9)
 299                 set_bit(X86_FEATURE_3DNOW, c->x86_capability);
 300
 301         get_model_name(c);
 302         display_cacheinfo(c);
 303 }
 304
 305 static void __init init_centaur(struct cpuinfo_x86 *c)
 306 {
 307         enum {
 308                 ECX8=1<<1,
 309                 EIERRINT=1<<2,
 310                 DPM=1<<3,
 311                 DMCE=1<<4,
 312                 DSTPCLK=1<<5,
 313                 ELINEAR=1<<6,
 314                 DSMC=1<<7,
 315                 DTLOCK=1<<8,
 316                 EDCTLB=1<<8,
 317                 EMMX=1<<9,
 318                 DPDC=1<<11,
 319                 EBRPRED=1<<12,
 320                 DIC=1<<13,
 321                 DDC=1<<14,
 322                 DNA=1<<15,
 323                 ERETSTK=1<<16,
 324                 E2MMX=1<<19,
 325                 EAMD3D=1<<20,
 326         };
 327
 328         char *name;
 329         u32  fcr_set=0;
 330         u32  fcr_clr=0;
 331         u32  lo,hi,newlo;
 332         u32  aa,bb,cc,dd;
 333
 334         /* Bit 31 in normal CPUID used for nonstandard 3DNow ID;
 335            3DNow is IDd by bit 31 in extended CPUID (1*32+31) anyway */
 336         clear_bit(0*32+31, c->x86_capability);
 337
 338         switch (c->x86) {
 339
 340                 case 5:
 341                         switch(c->x86_model) {
 342                         case 4:
 343                                 name="C6";
 344                                 fcr_set=ECX8|DSMC|EDCTLB|EMMX|ERETSTK;
 345                                 fcr_clr=DPDC;
 346                                 printk(KERN_NOTICE "Disabling bugged TSC.\n");
 347                                 clear_bit(X86_FEATURE_TSC, c->x86_capability);
 348 #ifdef CONFIG_X86_OOSTORE
 349                                 centaur_create_optimal_mcr();
 350                                 /* Enable
 351                                         write combining on non-stack, non-string
 352                                         write combining on string, all types
 353                                         weak write ordering
 354
 355                                    The C6 original lacks weak read order
 356
 357                                    Note 0x120 is write only on Winchip 1 */
 358
 359                                 wrmsr(MSR_IDT_MCR_CTRL, 0x01F0001F, 0);
 360 #endif
 361                                 break;
 362                         case 8:
 363                                 switch(c->x86_mask) {
 364                                 default:
 365                                         name="2";
 366                                         break;
 367                                 case 7 ... 9:
 368                                         name="2A";
 369                                         break;
 370                                 case 10 ... 15:
 371                                         name="2B";
 372                                         break;
 373                                 }
 374                                 fcr_set=ECX8|DSMC|DTLOCK|EMMX|EBRPRED|ERETSTK|E2MMX|EAMD3D;
 375                                 fcr_clr=DPDC;
 376 #ifdef CONFIG_X86_OOSTORE
 377                                 winchip2_unprotect_mcr();
 378                                 winchip2_create_optimal_mcr();
 379                                 rdmsr(MSR_IDT_MCR_CTRL, lo, hi);
 380                                 /* Enable
 381                                         write combining on non-stack, non-string
 382                                         write combining on string, all types
 383                                         weak write ordering
 384                                 */
 385                                 lo|=31;
 386                                 wrmsr(MSR_IDT_MCR_CTRL, lo, hi);
 387                                 winchip2_protect_mcr();
 388 #endif
 389                                 break;
 390                         case 9:
 391                                 name="3";
 392                                 fcr_set=ECX8|DSMC|DTLOCK|EMMX|EBRPRED|ERETSTK|E2MMX|EAMD3D;
 393                                 fcr_clr=DPDC;
 394 #ifdef CONFIG_X86_OOSTORE
 395                                 winchip2_unprotect_mcr();
 396                                 winchip2_create_optimal_mcr();
 397                                 rdmsr(MSR_IDT_MCR_CTRL, lo, hi);
 398                                 /* Enable
 399                                         write combining on non-stack, non-string
 400                                         write combining on string, all types
 401                                         weak write ordering
 402                                 */
 403                                 lo|=31;
 404                                 wrmsr(MSR_IDT_MCR_CTRL, lo, hi);
 405                                 winchip2_protect_mcr();
 406 #endif
 407                                 break;
 408                         case 10:
 409                                 name="4";
 410                                 /* no info on the WC4 yet */
 411                                 break;
 412                         default:
 413                                 name="??";
 414                         }
 415
 416                         rdmsr(MSR_IDT_FCR1, lo, hi);
 417                         newlo=(lo|fcr_set) & (~fcr_clr);
 418
 419                         if (newlo!=lo) {
 420                                 printk(KERN_INFO "Centaur FCR was 0x%X now 0x%X\n", lo, newlo );
 421                                 wrmsr(MSR_IDT_FCR1, newlo, hi );
 422                         } else {
 423                                 printk(KERN_INFO "Centaur FCR is 0x%X\n",lo);
 424                         }
 425                         /* Emulate MTRRs using Centaur's MCR. */
 426                         set_bit(X86_FEATURE_CENTAUR_MCR, c->x86_capability);
 427                         /* Report CX8 */
 428                         set_bit(X86_FEATURE_CX8, c->x86_capability);
 429                         /* Set 3DNow! on Winchip 2 and above. */
 430                         if (c->x86_model >=8)
 431                                 set_bit(X86_FEATURE_3DNOW, c->x86_capability);
 432                         /* See if we can find out some more. */
 433                         if ( cpuid_eax(0x80000000) >= 0x80000005 ) {
 434                                 /* Yes, we can. */
 435                                 cpuid(0x80000005,&aa,&bb,&cc,&dd);
 436                                 /* Add L1 data and code cache sizes. */
 437                                 c->x86_cache_size = (cc>>24)+(dd>>24);
 438                         }
 439                         sprintf( c->x86_model_id, "WinChip %s", name );
 440                         break;
 441
 442                 case 6:
 443                         init_c3(c);
 444                         break;
 445         }
 446 }
 447
 448 static unsigned int centaur_size_cache(struct cpuinfo_x86 * c, unsigned int size)
 449 {
 450         /* VIA C3 CPUs (670-68F) need further shifting. */
 451         if ((c->x86 == 6) && ((c->x86_model == 7) || (c->x86_model == 8)))
 452                 size >>= 8;
 453
 454         /* VIA also screwed up Nehemiah stepping 1, and made
 455            it return '65KB' instead of '64KB'
 456            - Note, it seems this may only be in engineering samples. */
 457         if ((c->x86==6) && (c->x86_model==9) && (c->x86_mask==1) && (size==65))
 458                 size -=1;
 459
 460         return size;
 461 }
 462
 463 static struct cpu_dev centaur_cpu_dev __initdata = {
 464         .c_vendor       = "Centaur",
 465         .c_ident        = { "CentaurHauls" },
 466         .c_init         = init_centaur,
 467         .c_size_cache   = centaur_size_cache,
 468 };
 469
 470 int __init centaur_init_cpu(void)
 471 {
 472         cpu_devs[X86_VENDOR_CENTAUR] = &centaur_cpu_dev;
 473         return 0;
 474 }
 475
 476 //early_arch_initcall(centaur_init_cpu);