arch/i386/kernel/cpu/amd.c

   1 #include <linux/init.h>
   2 #include <linux/bitops.h>
   3 #include <linux/mm.h>
   4 #include <asm/io.h>
   5 #include <asm/processor.h>
   6
   7 #include "cpu.h"
   8
   9 /*
  10  *      B step AMD K6 before B 9730xxxx have hardware bugs that can cause
  11  *      misexecution of code under Linux. Owners of such processors should
  12  *      contact AMD for precise details and a CPU swap.
  13  *
  14  *      See     http://www.multimania.com/poulot/k6bug.html
  15  *              http://www.amd.com/K6/k6docs/revgd.html
  16  *
  17  *      The following test is erm.. interesting. AMD neglected to up
  18  *      the chip setting when fixing the bug but they also tweaked some
  19  *      performance at the same time..
  20  */
  21
  22 extern void vide(void);
  23 __asm__(".align 4\nvide: ret");
  24
  25 static void __init init_amd(struct cpuinfo_x86 *c)
  26 {
  27         u32 l, h;
  28         int mbytes = num_physpages >> (20-PAGE_SHIFT);
  29         int r;
  30
  31         /*
  32          *      FIXME: We should handle the K5 here. Set up the write
  33          *      range and also turn on MSR 83 bits 4 and 31 (write alloc,
  34          *      no bus pipeline)
  35          */
  36
  37         /* Bit 31 in normal CPUID used for nonstandard 3DNow ID;
  38            3DNow is IDd by bit 31 in extended CPUID (1*32+31) anyway */
  39         clear_bit(0*32+31, c->x86_capability);
  40
  41         r = get_model_name(c);
  42
  43         switch(c->x86)
  44         {
  45                 case 4:
  46                 /*
  47                  * General Systems BIOSen alias the cpu frequency registers
  48                  * of the Elan at 0x000df000. Unfortuantly, one of the Linux
  49                  * drivers subsequently pokes it, and changes the CPU speed.
  50                  * Workaround : Remove the unneeded alias.
  51                  */
  52 #define CBAR            (0xfffc) /* Configuration Base Address  (32-bit) */
  53 #define CBAR_ENB        (0x80000000)
  54 #define CBAR_KEY        (0X000000CB)
  55                         if (c->x86_model==9 || c->x86_model == 10) {
  56                                 if (inl (CBAR) & CBAR_ENB)
  57                                         outl (0 | CBAR_KEY, CBAR);
  58                         }
  59                         break;
  60                 case 5:
  61                         if( c->x86_model < 6 )
  62                         {
  63                                 /* Based on AMD doc 20734R - June 2000 */
  64                                 if ( c->x86_model == 0 ) {
  65                                         clear_bit(X86_FEATURE_APIC, c->x86_capability);
  66                                         set_bit(X86_FEATURE_PGE, c->x86_capability);
  67                                 }
  68                                 break;
  69                         }
  70
  71                         if ( c->x86_model == 6 && c->x86_mask == 1 ) {
  72                                 const int K6_BUG_LOOP = 1000000;
  73                                 int n;
  74                                 void (*f_vide)(void);
  75                                 unsigned long d, d2;
  76
  77                                 printk(KERN_INFO "AMD K6 stepping B detected - ");
  78
  79                                 /*
  80                                  * It looks like AMD fixed the 2.6.2 bug and improved indirect
  81                                  * calls at the same time.
  82                                  */
  83
  84                                 n = K6_BUG_LOOP;
  85                                 f_vide = vide;
  86                                 rdtscl(d);
  87                                 while (n--)
  88                                         f_vide();
  89                                 rdtscl(d2);
  90                                 d = d2-d;
  91
  92                                 /* Knock these two lines out if it debugs out ok */
  93                                 printk(KERN_INFO "AMD K6 stepping B detected - ");
  94                                 /* -- cut here -- */
  95                                 if (d > 20*K6_BUG_LOOP)
  96                                         printk("system stability may be impaired when more than 32 MB are used.\n");
  97                                 else
  98                                         printk("probably OK (after B9730xxxx).\n");
  99                                 printk(KERN_INFO "Please see http://membres.lycos.fr/poulot/k6bug.html\n");
 100                         }
 101
 102                         /* K6 with old style WHCR */
 103                         if (c->x86_model < 8 ||
 104                            (c->x86_model== 8 && c->x86_mask < 8)) {
 105                                 /* We can only write allocate on the low 508Mb */
 106                                 if(mbytes>508)
 107                                         mbytes=508;
 108
 109                                 rdmsr(MSR_K6_WHCR, l, h);
 110                                 if ((l&0x0000FFFF)==0) {
 111                                         unsigned long flags;
 112                                         l=(1<<0)|((mbytes/4)<<1);
 113                                         local_irq_save(flags);
 114                                         wbinvd();
 115                                         wrmsr(MSR_K6_WHCR, l, h);
 116                                         local_irq_restore(flags);
 117                                         printk(KERN_INFO "Enabling old style K6 write allocation for %d Mb\n",
 118                                                 mbytes);
 119                                 }
 120                                 break;
 121                         }
 122
 123                         if ((c->x86_model == 8 && c->x86_mask >7) ||
 124                              c->x86_model == 9 || c->x86_model == 13) {
 125                                 /* The more serious chips .. */
 126
 127                                 if(mbytes>4092)
 128                                         mbytes=4092;
 129
 130                                 rdmsr(MSR_K6_WHCR, l, h);
 131                                 if ((l&0xFFFF0000)==0) {
 132                                         unsigned long flags;
 133                                         l=((mbytes>>2)<<22)|(1<<16);
 134                                         local_irq_save(flags);
 135                                         wbinvd();
 136                                         wrmsr(MSR_K6_WHCR, l, h);
 137                                         local_irq_restore(flags);
 138                                         printk(KERN_INFO "Enabling new style K6 write allocation for %d Mb\n",
 139                                                 mbytes);
 140                                 }
 141
 142                                 /*  Set MTRR capability flag if appropriate */
 143                                 if (c->x86_model == 13 || c->x86_model == 9 ||
 144                                    (c->x86_model == 8 && c->x86_mask >= 8))
 145                                         set_bit(X86_FEATURE_K6_MTRR, c->x86_capability);
 146                                 break;
 147                         }
 148                         break;
 149
 150                 case 6: /* An Athlon/Duron */
 151
 152                         /* Bit 15 of Athlon specific MSR 15, needs to be 0
 153                          * to enable SSE on Palomino/Morgan/Barton CPU's.
 154                          * If the BIOS didn't enable it already, enable it here.
 155                          */
 156                         if (c->x86_model >= 6 && c->x86_model <= 10) {
 157                                 if (!cpu_has(c, X86_FEATURE_XMM)) {
 158                                         printk(KERN_INFO "Enabling disabled K7/SSE Support.\n");
 159                                         rdmsr(MSR_K7_HWCR, l, h);
 160                                         l &= ~0x00008000;
 161                                         wrmsr(MSR_K7_HWCR, l, h);
 162                                         set_bit(X86_FEATURE_XMM, c->x86_capability);
 163                                 }
 164                         }
 165
 166                         /* It's been determined by AMD that Athlons since model 8 stepping 1
 167                          * are more robust with CLK_CTL set to 200xxxxx instead of 600xxxxx
 168                          * As per AMD technical note 27212 0.2
 169                          */
 170                         if ((c->x86_model == 8 && c->x86_mask>=1) || (c->x86_model > 8)) {
 171                                 rdmsr(MSR_K7_CLK_CTL, l, h);
 172                                 if ((l & 0xfff00000) != 0x20000000) {
 173                                         printk ("CPU: CLK_CTL MSR was %x. Reprogramming to %x\n", l,
 174                                                 ((l & 0x000fffff)|0x20000000));
 175                                         wrmsr(MSR_K7_CLK_CTL, (l & 0x000fffff)|0x20000000, h);
 176                                 }
 177                         }
 178                         break;
 179         }
 180
 181         switch (c->x86) {
 182         case 15:
 183                 set_bit(X86_FEATURE_K8, c->x86_capability);
 184                 break;
 185         case 6:
 186                 set_bit(X86_FEATURE_K7, c->x86_capability);
 187                 break;
 188         }
 189
 190         display_cacheinfo(c);
 191
 192         if (cpuid_eax(0x80000000) >= 0x80000008) {
 193                 c->x86_num_cores = (cpuid_ecx(0x80000008) & 0xff) + 1;
 194                 if (c->x86_num_cores & (c->x86_num_cores - 1))
 195                         c->x86_num_cores = 1;
 196         }
 197
 198 #ifdef CONFIG_X86_SMP
 199         /*
 200          * On a AMD dual core setup the lower bits of the APIC id
 201          * distingush the cores.  Assumes number of cores is a power
 202          * of two.
 203          */
 204         if (c->x86_num_cores > 1) {
 205                 int cpu = smp_processor_id();
 206                 /* Fix up the APIC ID following AMD specifications. */
 207                 cpu_core_id[cpu] >>= hweight32(c->x86_num_cores - 1);
 208                 printk(KERN_INFO "CPU %d(%d) -> Core %d\n",
 209                        cpu, c->x86_num_cores, cpu_core_id[cpu]);
 210         }
 211 #endif
 212 }
 213
 214 static unsigned int amd_size_cache(struct cpuinfo_x86 * c, unsigned int size)
 215 {
 216         /* AMD errata T13 (order #21922) */
 217         if ((c->x86 == 6)) {
 218                 if (c->x86_model == 3 && c->x86_mask == 0)      /* Duron Rev A0 */
 219                         size = 64;
 220                 if (c->x86_model == 4 &&
 221                     (c->x86_mask==0 || c->x86_mask==1)) /* Tbird rev A1/A2 */
 222                         size = 256;
 223         }
 224         return size;
 225 }
 226
 227 static struct cpu_dev amd_cpu_dev __initdata = {
 228         .c_vendor       = "AMD",
 229         .c_ident        = { "AuthenticAMD" },
 230         .c_models = {
 231                 { .vendor = X86_VENDOR_AMD, .family = 4, .model_names =
 232                   {
 233                           [3] = "486 DX/2",
 234                           [7] = "486 DX/2-WB",
 235                           [8] = "486 DX/4",
 236                           [9] = "486 DX/4-WB",
 237                           [14] = "Am5x86-WT",
 238                           [15] = "Am5x86-WB"
 239                   }
 240                 },
 241         },
 242         .c_init         = init_amd,
 243         .c_identify     = generic_identify,
 244         .c_size_cache   = amd_size_cache,
 245 };
 246
 247 int __init amd_init_cpu(void)
 248 {
 249         cpu_devs[X86_VENDOR_AMD] = &amd_cpu_dev;
 250         return 0;
 251 }
 252
 253 //early_arch_initcall(amd_init_cpu);