git.oblomov.eu Git - linux-2.6/blob - arch/x86/kernel/cpu/cpufreq/powernow-k7.c

   1 /*
   2  *  AMD K7 Powernow driver.
   3  *  (C) 2003 Dave Jones on behalf of SuSE Labs.
   4  *  (C) 2003-2004 Dave Jones <davej@redhat.com>
   5  *
   6  *  Licensed under the terms of the GNU GPL License version 2.
   7  *  Based upon datasheets & sample CPUs kindly provided by AMD.
   8  *
   9  * Errata 5:
  10  *  CPU may fail to execute a FID/VID change in presence of interrupt.
  11  *  - We cli/sti on stepping A0 CPUs around the FID/VID transition.
  12  * Errata 15:
  13  *  CPU with half frequency multipliers may hang upon wakeup from disconnect.
  14  *  - We disable half multipliers if ACPI is used on A0 stepping CPUs.
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/moduleparam.h>
  20 #include <linux/init.h>
  21 #include <linux/cpufreq.h>
  22 #include <linux/slab.h>
  23 #include <linux/string.h>
  24 #include <linux/dmi.h>
  25 #include <linux/timex.h>
  26 #include <linux/io.h>
  27
  28 #include <asm/timer.h>          /* Needed for recalibrate_cpu_khz() */
  29 #include <asm/msr.h>
  30 #include <asm/system.h>
  31
  32 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
  33 #include <linux/acpi.h>
  34 #include <acpi/processor.h>
  35 #endif
  36
  37 #include "powernow-k7.h"
  38
  39 #define PFX "powernow: "
  40
  41
  42 struct psb_s {
  43         u8 signature[10];
  44         u8 tableversion;
  45         u8 flags;
  46         u16 settlingtime;
  47         u8 reserved1;
  48         u8 numpst;
  49 };
  50
  51 struct pst_s {
  52         u32 cpuid;
  53         u8 fsbspeed;
  54         u8 maxfid;
  55         u8 startvid;
  56         u8 numpstates;
  57 };
  58
  59 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
  60 union powernow_acpi_control_t {
  61         struct {
  62                 unsigned long fid:5,
  63                         vid:5,
  64                         sgtc:20,
  65                         res1:2;
  66         } bits;
  67         unsigned long val;
  68 };
  69 #endif
  70
  71 #ifdef CONFIG_CPU_FREQ_DEBUG
  72 /* divide by 1000 to get VCore voltage in V. */
  73 static const int mobile_vid_table[32] = {
  74     2000, 1950, 1900, 1850, 1800, 1750, 1700, 1650,
  75     1600, 1550, 1500, 1450, 1400, 1350, 1300, 0,
  76     1275, 1250, 1225, 1200, 1175, 1150, 1125, 1100,
  77     1075, 1050, 1025, 1000, 975, 950, 925, 0,
  78 };
  79 #endif
  80
  81 /* divide by 10 to get FID. */
  82 static const int fid_codes[32] = {
  83     110, 115, 120, 125, 50, 55, 60, 65,
  84     70, 75, 80, 85, 90, 95, 100, 105,
  85     30, 190, 40, 200, 130, 135, 140, 210,
  86     150, 225, 160, 165, 170, 180, -1, -1,
  87 };
  88
  89 /* This parameter is used in order to force ACPI instead of legacy method for
  90  * configuration purpose.
  91  */
  92
  93 static int acpi_force;
  94
  95 static struct cpufreq_frequency_table *powernow_table;
  96
  97 static unsigned int can_scale_bus;
  98 static unsigned int can_scale_vid;
  99 static unsigned int minimum_speed = -1;
 100 static unsigned int maximum_speed;
 101 static unsigned int number_scales;
 102 static unsigned int fsb;
 103 static unsigned int latency;
 104 static char have_a0;
 105
 106 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, \
 107                 "powernow-k7", msg)
 108
 109 static int check_fsb(unsigned int fsbspeed)
 110 {
 111         int delta;
 112         unsigned int f = fsb / 1000;
 113
 114         delta = (fsbspeed > f) ? fsbspeed - f : f - fsbspeed;
 115         return delta < 5;
 116 }
 117
 118 static int check_powernow(void)
 119 {
 120         struct cpuinfo_x86 *c = &cpu_data(0);
 121         unsigned int maxei, eax, ebx, ecx, edx;
 122
 123         if ((c->x86_vendor != X86_VENDOR_AMD) || (c->x86 != 6)) {
 124 #ifdef MODULE
 125                 printk(KERN_INFO PFX "This module only works with "
 126                                 "AMD K7 CPUs\n");
 127 #endif
 128                 return 0;
 129         }
 130
 131         /* Get maximum capabilities */
 132         maxei = cpuid_eax(0x80000000);
 133         if (maxei < 0x80000007) {       /* Any powernow info ? */
 134 #ifdef MODULE
 135                 printk(KERN_INFO PFX "No powernow capabilities detected\n");
 136 #endif
 137                 return 0;
 138         }
 139
 140         if ((c->x86_model == 6) && (c->x86_mask == 0)) {
 141                 printk(KERN_INFO PFX "K7 660[A0] core detected, "
 142                                 "enabling errata workarounds\n");
 143                 have_a0 = 1;
 144         }
 145
 146         cpuid(0x80000007, &eax, &ebx, &ecx, &edx);
 147
 148         /* Check we can actually do something before we say anything.*/
 149         if (!(edx & (1 << 1 | 1 << 2)))
 150                 return 0;
 151
 152         printk(KERN_INFO PFX "PowerNOW! Technology present. Can scale: ");
 153
 154         if (edx & 1 << 1) {
 155                 printk("frequency");
 156                 can_scale_bus = 1;
 157         }
 158
 159         if ((edx & (1 << 1 | 1 << 2)) == 0x6)
 160                 printk(" and ");
 161
 162         if (edx & 1 << 2) {
 163                 printk("voltage");
 164                 can_scale_vid = 1;
 165         }
 166
 167         printk(".\n");
 168         return 1;
 169 }
 170
 171 static void invalidate_entry(unsigned int entry)
 172 {
 173         powernow_table[entry].frequency = CPUFREQ_ENTRY_INVALID;
 174 }
 175
 176 static int get_ranges(unsigned char *pst)
 177 {
 178         unsigned int j;
 179         unsigned int speed;
 180         u8 fid, vid;
 181
 182         powernow_table = kzalloc((sizeof(struct cpufreq_frequency_table) *
 183                                 (number_scales + 1)), GFP_KERNEL);
 184         if (!powernow_table)
 185                 return -ENOMEM;
 186
 187         for (j = 0 ; j < number_scales; j++) {
 188                 fid = *pst++;
 189
 190                 powernow_table[j].frequency = (fsb * fid_codes[fid]) / 10;
 191                 powernow_table[j].index = fid; /* lower 8 bits */
 192
 193                 speed = powernow_table[j].frequency;
 194
 195                 if ((fid_codes[fid] % 10) == 5) {
 196 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 197                         if (have_a0 == 1)
 198                                 invalidate_entry(j);
 199 #endif
 200                 }
 201
 202                 if (speed < minimum_speed)
 203                         minimum_speed = speed;
 204                 if (speed > maximum_speed)
 205                         maximum_speed = speed;
 206
 207                 vid = *pst++;
 208                 powernow_table[j].index |= (vid << 8); /* upper 8 bits */
 209
 210                 dprintk("   FID: 0x%x (%d.%dx [%dMHz])  "
 211                          "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
 212                          fid_codes[fid] % 10, speed/1000, vid,
 213                          mobile_vid_table[vid]/1000,
 214                          mobile_vid_table[vid]%1000);
 215         }
 216         powernow_table[number_scales].frequency = CPUFREQ_TABLE_END;
 217         powernow_table[number_scales].index = 0;
 218
 219         return 0;
 220 }
 221
 222
 223 static void change_FID(int fid)
 224 {
 225         union msr_fidvidctl fidvidctl;
 226
 227         rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 228         if (fidvidctl.bits.FID != fid) {
 229                 fidvidctl.bits.SGTC = latency;
 230                 fidvidctl.bits.FID = fid;
 231                 fidvidctl.bits.VIDC = 0;
 232                 fidvidctl.bits.FIDC = 1;
 233                 wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 234         }
 235 }
 236
 237
 238 static void change_VID(int vid)
 239 {
 240         union msr_fidvidctl fidvidctl;
 241
 242         rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 243         if (fidvidctl.bits.VID != vid) {
 244                 fidvidctl.bits.SGTC = latency;
 245                 fidvidctl.bits.VID = vid;
 246                 fidvidctl.bits.FIDC = 0;
 247                 fidvidctl.bits.VIDC = 1;
 248                 wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 249         }
 250 }
 251
 252
 253 static void change_speed(unsigned int index)
 254 {
 255         u8 fid, vid;
 256         struct cpufreq_freqs freqs;
 257         union msr_fidvidstatus fidvidstatus;
 258         int cfid;
 259
 260         /* fid are the lower 8 bits of the index we stored into
 261          * the cpufreq frequency table in powernow_decode_bios,
 262          * vid are the upper 8 bits.
 263          */
 264
 265         fid = powernow_table[index].index & 0xFF;
 266         vid = (powernow_table[index].index & 0xFF00) >> 8;
 267
 268         freqs.cpu = 0;
 269
 270         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 271         cfid = fidvidstatus.bits.CFID;
 272         freqs.old = fsb * fid_codes[cfid] / 10;
 273
 274         freqs.new = powernow_table[index].frequency;
 275
 276         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 277
 278         /* Now do the magic poking into the MSRs.  */
 279
 280         if (have_a0 == 1)       /* A0 errata 5 */
 281                 local_irq_disable();
 282
 283         if (freqs.old > freqs.new) {
 284                 /* Going down, so change FID first */
 285                 change_FID(fid);
 286                 change_VID(vid);
 287         } else {
 288                 /* Going up, so change VID first */
 289                 change_VID(vid);
 290                 change_FID(fid);
 291         }
 292
 293
 294         if (have_a0 == 1)
 295                 local_irq_enable();
 296
 297         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 298 }
 299
 300
 301 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 302
 303 static struct acpi_processor_performance *acpi_processor_perf;
 304
 305 static int powernow_acpi_init(void)
 306 {
 307         int i;
 308         int retval = 0;
 309         union powernow_acpi_control_t pc;
 310
 311         if (acpi_processor_perf != NULL && powernow_table != NULL) {
 312                 retval = -EINVAL;
 313                 goto err0;
 314         }
 315
 316         acpi_processor_perf = kzalloc(sizeof(struct acpi_processor_performance),
 317                                       GFP_KERNEL);
 318         if (!acpi_processor_perf) {
 319                 retval = -ENOMEM;
 320                 goto err0;
 321         }
 322
 323         if (!alloc_cpumask_var(&acpi_processor_perf->shared_cpu_map,
 324                                                                 GFP_KERNEL)) {
 325                 retval = -ENOMEM;
 326                 goto err05;
 327         }
 328
 329         if (acpi_processor_register_performance(acpi_processor_perf, 0)) {
 330                 retval = -EIO;
 331                 goto err1;
 332         }
 333
 334         if (acpi_processor_perf->control_register.space_id !=
 335                         ACPI_ADR_SPACE_FIXED_HARDWARE) {
 336                 retval = -ENODEV;
 337                 goto err2;
 338         }
 339
 340         if (acpi_processor_perf->status_register.space_id !=
 341                         ACPI_ADR_SPACE_FIXED_HARDWARE) {
 342                 retval = -ENODEV;
 343                 goto err2;
 344         }
 345
 346         number_scales = acpi_processor_perf->state_count;
 347
 348         if (number_scales < 2) {
 349                 retval = -ENODEV;
 350                 goto err2;
 351         }
 352
 353         powernow_table = kzalloc((sizeof(struct cpufreq_frequency_table) *
 354                                 (number_scales + 1)), GFP_KERNEL);
 355         if (!powernow_table) {
 356                 retval = -ENOMEM;
 357                 goto err2;
 358         }
 359
 360         pc.val = (unsigned long) acpi_processor_perf->states[0].control;
 361         for (i = 0; i < number_scales; i++) {
 362                 u8 fid, vid;
 363                 struct acpi_processor_px *state =
 364                         &acpi_processor_perf->states[i];
 365                 unsigned int speed, speed_mhz;
 366
 367                 pc.val = (unsigned long) state->control;
 368                 dprintk("acpi:  P%d: %d MHz %d mW %d uS control %08x SGTC %d\n",
 369                          i,
 370                          (u32) state->core_frequency,
 371                          (u32) state->power,
 372                          (u32) state->transition_latency,
 373                          (u32) state->control,
 374                          pc.bits.sgtc);
 375
 376                 vid = pc.bits.vid;
 377                 fid = pc.bits.fid;
 378
 379                 powernow_table[i].frequency = fsb * fid_codes[fid] / 10;
 380                 powernow_table[i].index = fid; /* lower 8 bits */
 381                 powernow_table[i].index |= (vid << 8); /* upper 8 bits */
 382
 383                 speed = powernow_table[i].frequency;
 384                 speed_mhz = speed / 1000;
 385
 386                 /* processor_perflib will multiply the MHz value by 1000 to
 387                  * get a KHz value (e.g. 1266000). However, powernow-k7 works
 388                  * with true KHz values (e.g. 1266768). To ensure that all
 389                  * powernow frequencies are available, we must ensure that
 390                  * ACPI doesn't restrict them, so we round up the MHz value
 391                  * to ensure that perflib's computed KHz value is greater than
 392                  * or equal to powernow's KHz value.
 393                  */
 394                 if (speed % 1000 > 0)
 395                         speed_mhz++;
 396
 397                 if ((fid_codes[fid] % 10) == 5) {
 398                         if (have_a0 == 1)
 399                                 invalidate_entry(i);
 400                 }
 401
 402                 dprintk("   FID: 0x%x (%d.%dx [%dMHz])  "
 403                          "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
 404                          fid_codes[fid] % 10, speed_mhz, vid,
 405                          mobile_vid_table[vid]/1000,
 406                          mobile_vid_table[vid]%1000);
 407
 408                 if (state->core_frequency != speed_mhz) {
 409                         state->core_frequency = speed_mhz;
 410                         dprintk("   Corrected ACPI frequency to %d\n",
 411                                 speed_mhz);
 412                 }
 413
 414                 if (latency < pc.bits.sgtc)
 415                         latency = pc.bits.sgtc;
 416
 417                 if (speed < minimum_speed)
 418                         minimum_speed = speed;
 419                 if (speed > maximum_speed)
 420                         maximum_speed = speed;
 421         }
 422
 423         powernow_table[i].frequency = CPUFREQ_TABLE_END;
 424         powernow_table[i].index = 0;
 425
 426         /* notify BIOS that we exist */
 427         acpi_processor_notify_smm(THIS_MODULE);
 428
 429         return 0;
 430
 431 err2:
 432         acpi_processor_unregister_performance(acpi_processor_perf, 0);
 433 err1:
 434         free_cpumask_var(acpi_processor_perf->shared_cpu_map);
 435 err05:
 436         kfree(acpi_processor_perf);
 437 err0:
 438         printk(KERN_WARNING PFX "ACPI perflib can not be used on "
 439                         "this platform\n");
 440         acpi_processor_perf = NULL;
 441         return retval;
 442 }
 443 #else
 444 static int powernow_acpi_init(void)
 445 {
 446         printk(KERN_INFO PFX "no support for ACPI processor found."
 447                "  Please recompile your kernel with ACPI processor\n");
 448         return -EINVAL;
 449 }
 450 #endif
 451
 452 static void print_pst_entry(struct pst_s *pst, unsigned int j)
 453 {
 454         dprintk("PST:%d (@%p)\n", j, pst);
 455         dprintk(" cpuid: 0x%x  fsb: %d  maxFID: 0x%x  startvid: 0x%x\n",
 456                 pst->cpuid, pst->fsbspeed, pst->maxfid, pst->startvid);
 457 }
 458
 459 static int powernow_decode_bios(int maxfid, int startvid)
 460 {
 461         struct psb_s *psb;
 462         struct pst_s *pst;
 463         unsigned int i, j;
 464         unsigned char *p;
 465         unsigned int etuple;
 466         unsigned int ret;
 467
 468         etuple = cpuid_eax(0x80000001);
 469
 470         for (i = 0xC0000; i < 0xffff0 ; i += 16) {
 471
 472                 p = phys_to_virt(i);
 473
 474                 if (memcmp(p, "AMDK7PNOW!",  10) == 0) {
 475                         dprintk("Found PSB header at %p\n", p);
 476                         psb = (struct psb_s *) p;
 477                         dprintk("Table version: 0x%x\n", psb->tableversion);
 478                         if (psb->tableversion != 0x12) {
 479                                 printk(KERN_INFO PFX "Sorry, only v1.2 tables"
 480                                                 " supported right now\n");
 481                                 return -ENODEV;
 482                         }
 483
 484                         dprintk("Flags: 0x%x\n", psb->flags);
 485                         if ((psb->flags & 1) == 0)
 486                                 dprintk("Mobile voltage regulator\n");
 487                         else
 488                                 dprintk("Desktop voltage regulator\n");
 489
 490                         latency = psb->settlingtime;
 491                         if (latency < 100) {
 492                                 printk(KERN_INFO PFX "BIOS set settling time "
 493                                                 "to %d microseconds. "
 494                                                 "Should be at least 100. "
 495                                                 "Correcting.\n", latency);
 496                                 latency = 100;
 497                         }
 498                         dprintk("Settling Time: %d microseconds.\n",
 499                                         psb->settlingtime);
 500                         dprintk("Has %d PST tables. (Only dumping ones "
 501                                         "relevant to this CPU).\n",
 502                                         psb->numpst);
 503
 504                         p += sizeof(struct psb_s);
 505
 506                         pst = (struct pst_s *) p;
 507
 508                         for (j = 0; j < psb->numpst; j++) {
 509                                 pst = (struct pst_s *) p;
 510                                 number_scales = pst->numpstates;
 511
 512                                 if ((etuple == pst->cpuid) &&
 513                                     check_fsb(pst->fsbspeed) &&
 514                                     (maxfid == pst->maxfid) &&
 515                                     (startvid == pst->startvid)) {
 516                                         print_pst_entry(pst, j);
 517                                         p = (char *)pst + sizeof(struct pst_s);
 518                                         ret = get_ranges(p);
 519                                         return ret;
 520                                 } else {
 521                                         unsigned int k;
 522                                         p = (char *)pst + sizeof(struct pst_s);
 523                                         for (k = 0; k < number_scales; k++)
 524                                                 p += 2;
 525                                 }
 526                         }
 527                         printk(KERN_INFO PFX "No PST tables match this cpuid "
 528                                         "(0x%x)\n", etuple);
 529                         printk(KERN_INFO PFX "This is indicative of a broken "
 530                                         "BIOS.\n");
 531
 532                         return -EINVAL;
 533                 }
 534                 p++;
 535         }
 536
 537         return -ENODEV;
 538 }
 539
 540
 541 static int powernow_target(struct cpufreq_policy *policy,
 542                             unsigned int target_freq,
 543                             unsigned int relation)
 544 {
 545         unsigned int newstate;
 546
 547         if (cpufreq_frequency_table_target(policy, powernow_table, target_freq,
 548                                 relation, &newstate))
 549                 return -EINVAL;
 550
 551         change_speed(newstate);
 552
 553         return 0;
 554 }
 555
 556
 557 static int powernow_verify(struct cpufreq_policy *policy)
 558 {
 559         return cpufreq_frequency_table_verify(policy, powernow_table);
 560 }
 561
 562 /*
 563  * We use the fact that the bus frequency is somehow
 564  * a multiple of 100000/3 khz, then we compute sgtc according
 565  * to this multiple.
 566  * That way, we match more how AMD thinks all of that work.
 567  * We will then get the same kind of behaviour already tested under
 568  * the "well-known" other OS.
 569  */
 570 static int __init fixup_sgtc(void)
 571 {
 572         unsigned int sgtc;
 573         unsigned int m;
 574
 575         m = fsb / 3333;
 576         if ((m % 10) >= 5)
 577                 m += 5;
 578
 579         m /= 10;
 580
 581         sgtc = 100 * m * latency;
 582         sgtc = sgtc / 3;
 583         if (sgtc > 0xfffff) {
 584                 printk(KERN_WARNING PFX "SGTC too large %d\n", sgtc);
 585                 sgtc = 0xfffff;
 586         }
 587         return sgtc;
 588 }
 589
 590 static unsigned int powernow_get(unsigned int cpu)
 591 {
 592         union msr_fidvidstatus fidvidstatus;
 593         unsigned int cfid;
 594
 595         if (cpu)
 596                 return 0;
 597         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 598         cfid = fidvidstatus.bits.CFID;
 599
 600         return fsb * fid_codes[cfid] / 10;
 601 }
 602
 603
 604 static int __init acer_cpufreq_pst(const struct dmi_system_id *d)
 605 {
 606         printk(KERN_WARNING PFX
 607                 "%s laptop with broken PST tables in BIOS detected.\n",
 608                 d->ident);
 609         printk(KERN_WARNING PFX
 610                 "You need to downgrade to 3A21 (09/09/2002), or try a newer "
 611                 "BIOS than 3A71 (01/20/2003)\n");
 612         printk(KERN_WARNING PFX
 613                 "cpufreq scaling has been disabled as a result of this.\n");
 614         return 0;
 615 }
 616
 617 /*
 618  * Some Athlon laptops have really fucked PST tables.
 619  * A BIOS update is all that can save them.
 620  * Mention this, and disable cpufreq.
 621  */
 622 static struct dmi_system_id __initdata powernow_dmi_table[] = {
 623         {
 624                 .callback = acer_cpufreq_pst,
 625                 .ident = "Acer Aspire",
 626                 .matches = {
 627                         DMI_MATCH(DMI_SYS_VENDOR, "Insyde Software"),
 628                         DMI_MATCH(DMI_BIOS_VERSION, "3A71"),
 629                 },
 630         },
 631         { }
 632 };
 633
 634 static int __init powernow_cpu_init(struct cpufreq_policy *policy)
 635 {
 636         union msr_fidvidstatus fidvidstatus;
 637         int result;
 638
 639         if (policy->cpu != 0)
 640                 return -ENODEV;
 641
 642         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 643
 644         recalibrate_cpu_khz();
 645
 646         fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.CFID];
 647         if (!fsb) {
 648                 printk(KERN_WARNING PFX "can not determine bus frequency\n");
 649                 return -EINVAL;
 650         }
 651         dprintk("FSB: %3dMHz\n", fsb/1000);
 652
 653         if (dmi_check_system(powernow_dmi_table) || acpi_force) {
 654                 printk(KERN_INFO PFX "PSB/PST known to be broken.  "
 655                                 "Trying ACPI instead\n");
 656                 result = powernow_acpi_init();
 657         } else {
 658                 result = powernow_decode_bios(fidvidstatus.bits.MFID,
 659                                 fidvidstatus.bits.SVID);
 660                 if (result) {
 661                         printk(KERN_INFO PFX "Trying ACPI perflib\n");
 662                         maximum_speed = 0;
 663                         minimum_speed = -1;
 664                         latency = 0;
 665                         result = powernow_acpi_init();
 666                         if (result) {
 667                                 printk(KERN_INFO PFX
 668                                         "ACPI and legacy methods failed\n");
 669                         }
 670                 } else {
 671                         /* SGTC use the bus clock as timer */
 672                         latency = fixup_sgtc();
 673                         printk(KERN_INFO PFX "SGTC: %d\n", latency);
 674                 }
 675         }
 676
 677         if (result)
 678                 return result;
 679
 680         printk(KERN_INFO PFX "Minimum speed %d MHz. Maximum speed %d MHz.\n",
 681                                 minimum_speed/1000, maximum_speed/1000);
 682
 683         policy->cpuinfo.transition_latency =
 684                 cpufreq_scale(2000000UL, fsb, latency);
 685
 686         policy->cur = powernow_get(0);
 687
 688         cpufreq_frequency_table_get_attr(powernow_table, policy->cpu);
 689
 690         return cpufreq_frequency_table_cpuinfo(policy, powernow_table);
 691 }
 692
 693 static int powernow_cpu_exit(struct cpufreq_policy *policy)
 694 {
 695         cpufreq_frequency_table_put_attr(policy->cpu);
 696
 697 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 698         if (acpi_processor_perf) {
 699                 acpi_processor_unregister_performance(acpi_processor_perf, 0);
 700                 free_cpumask_var(acpi_processor_perf->shared_cpu_map);
 701                 kfree(acpi_processor_perf);
 702         }
 703 #endif
 704
 705         kfree(powernow_table);
 706         return 0;
 707 }
 708
 709 static struct freq_attr *powernow_table_attr[] = {
 710         &cpufreq_freq_attr_scaling_available_freqs,
 711         NULL,
 712 };
 713
 714 static struct cpufreq_driver powernow_driver = {
 715         .verify = powernow_verify,
 716         .target = powernow_target,
 717         .get    = powernow_get,
 718         .init   = powernow_cpu_init,
 719         .exit   = powernow_cpu_exit,
 720         .name   = "powernow-k7",
 721         .owner  = THIS_MODULE,
 722         .attr   = powernow_table_attr,
 723 };
 724
 725 static int __init powernow_init(void)
 726 {
 727         if (check_powernow() == 0)
 728                 return -ENODEV;
 729         return cpufreq_register_driver(&powernow_driver);
 730 }
 731
 732
 733 static void __exit powernow_exit(void)
 734 {
 735         cpufreq_unregister_driver(&powernow_driver);
 736 }
 737
 738 module_param(acpi_force,  int, 0444);
 739 MODULE_PARM_DESC(acpi_force, "Force ACPI to be used.");
 740
 741 MODULE_AUTHOR("Dave Jones <davej@redhat.com>");
 742 MODULE_DESCRIPTION("Powernow driver for AMD K7 processors.");
 743 MODULE_LICENSE("GPL");
 744
 745 late_initcall(powernow_init);
 746 module_exit(powernow_exit);
 747