drivers/cpufreq/powernow-k7.c

   1 /*
   2  *  AMD K7 Powernow driver.
   3  *  (C) 2003 Dave Jones on behalf of SuSE Labs.
   4  *
   5  *  Licensed under the terms of the GNU GPL License version 2.
   6  *  Based upon datasheets & sample CPUs kindly provided by AMD.
   7  *
   8  * Errata 5:
   9  *  CPU may fail to execute a FID/VID change in presence of interrupt.
  10  *  - We cli/sti on stepping A0 CPUs around the FID/VID transition.
  11  * Errata 15:
  12  *  CPU with half frequency multipliers may hang upon wakeup from disconnect.
  13  *  - We disable half multipliers if ACPI is used on A0 stepping CPUs.
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/moduleparam.h>
  19 #include <linux/init.h>
  20 #include <linux/cpufreq.h>
  21 #include <linux/slab.h>
  22 #include <linux/string.h>
  23 #include <linux/dmi.h>
  24 #include <linux/timex.h>
  25 #include <linux/io.h>
  26
  27 #include <asm/timer.h>          /* Needed for recalibrate_cpu_khz() */
  28 #include <asm/msr.h>
  29 #include <asm/cpu_device_id.h>
  30
  31 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
  32 #include <linux/acpi.h>
  33 #include <acpi/processor.h>
  34 #endif
  35
  36 #include "powernow-k7.h"
  37
  38 #define PFX "powernow: "
  39
  40
  41 struct psb_s {
  42         u8 signature[10];
  43         u8 tableversion;
  44         u8 flags;
  45         u16 settlingtime;
  46         u8 reserved1;
  47         u8 numpst;
  48 };
  49
  50 struct pst_s {
  51         u32 cpuid;
  52         u8 fsbspeed;
  53         u8 maxfid;
  54         u8 startvid;
  55         u8 numpstates;
  56 };
  57
  58 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
  59 union powernow_acpi_control_t {
  60         struct {
  61                 unsigned long fid:5,
  62                         vid:5,
  63                         sgtc:20,
  64                         res1:2;
  65         } bits;
  66         unsigned long val;
  67 };
  68 #endif
  69
  70 /* divide by 1000 to get VCore voltage in V. */
  71 static const int mobile_vid_table[32] = {
  72     2000, 1950, 1900, 1850, 1800, 1750, 1700, 1650,
  73     1600, 1550, 1500, 1450, 1400, 1350, 1300, 0,
  74     1275, 1250, 1225, 1200, 1175, 1150, 1125, 1100,
  75     1075, 1050, 1025, 1000, 975, 950, 925, 0,
  76 };
  77
  78 /* divide by 10 to get FID. */
  79 static const int fid_codes[32] = {
  80     110, 115, 120, 125, 50, 55, 60, 65,
  81     70, 75, 80, 85, 90, 95, 100, 105,
  82     30, 190, 40, 200, 130, 135, 140, 210,
  83     150, 225, 160, 165, 170, 180, -1, -1,
  84 };
  85
  86 /* This parameter is used in order to force ACPI instead of legacy method for
  87  * configuration purpose.
  88  */
  89
  90 static int acpi_force;
  91
  92 static struct cpufreq_frequency_table *powernow_table;
  93
  94 static unsigned int can_scale_bus;
  95 static unsigned int can_scale_vid;
  96 static unsigned int minimum_speed = -1;
  97 static unsigned int maximum_speed;
  98 static unsigned int number_scales;
  99 static unsigned int fsb;
 100 static unsigned int latency;
 101 static char have_a0;
 102
 103 static int check_fsb(unsigned int fsbspeed)
 104 {
 105         int delta;
 106         unsigned int f = fsb / 1000;
 107
 108         delta = (fsbspeed > f) ? fsbspeed - f : f - fsbspeed;
 109         return delta < 5;
 110 }
 111
 112 static const struct x86_cpu_id powernow_k7_cpuids[] = {
 113         { X86_VENDOR_AMD, 6, },
 114         {}
 115 };
 116 MODULE_DEVICE_TABLE(x86cpu, powernow_k7_cpuids);
 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 (!x86_match_cpu(powernow_k7_cpuids))
 124                 return 0;
 125
 126         /* Get maximum capabilities */
 127         maxei = cpuid_eax(0x80000000);
 128         if (maxei < 0x80000007) {       /* Any powernow info ? */
 129 #ifdef MODULE
 130                 printk(KERN_INFO PFX "No powernow capabilities detected\n");
 131 #endif
 132                 return 0;
 133         }
 134
 135         if ((c->x86_model == 6) && (c->x86_mask == 0)) {
 136                 printk(KERN_INFO PFX "K7 660[A0] core detected, "
 137                                 "enabling errata workarounds\n");
 138                 have_a0 = 1;
 139         }
 140
 141         cpuid(0x80000007, &eax, &ebx, &ecx, &edx);
 142
 143         /* Check we can actually do something before we say anything.*/
 144         if (!(edx & (1 << 1 | 1 << 2)))
 145                 return 0;
 146
 147         printk(KERN_INFO PFX "PowerNOW! Technology present. Can scale: ");
 148
 149         if (edx & 1 << 1) {
 150                 printk("frequency");
 151                 can_scale_bus = 1;
 152         }
 153
 154         if ((edx & (1 << 1 | 1 << 2)) == 0x6)
 155                 printk(" and ");
 156
 157         if (edx & 1 << 2) {
 158                 printk("voltage");
 159                 can_scale_vid = 1;
 160         }
 161
 162         printk(".\n");
 163         return 1;
 164 }
 165
 166 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 167 static void invalidate_entry(unsigned int entry)
 168 {
 169         powernow_table[entry].frequency = CPUFREQ_ENTRY_INVALID;
 170 }
 171 #endif
 172
 173 static int get_ranges(unsigned char *pst)
 174 {
 175         unsigned int j;
 176         unsigned int speed;
 177         u8 fid, vid;
 178
 179         powernow_table = kzalloc((sizeof(*powernow_table) *
 180                                 (number_scales + 1)), GFP_KERNEL);
 181         if (!powernow_table)
 182                 return -ENOMEM;
 183
 184         for (j = 0 ; j < number_scales; j++) {
 185                 fid = *pst++;
 186
 187                 powernow_table[j].frequency = (fsb * fid_codes[fid]) / 10;
 188                 powernow_table[j].driver_data = fid; /* lower 8 bits */
 189
 190                 speed = powernow_table[j].frequency;
 191
 192                 if ((fid_codes[fid] % 10) == 5) {
 193 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 194                         if (have_a0 == 1)
 195                                 invalidate_entry(j);
 196 #endif
 197                 }
 198
 199                 if (speed < minimum_speed)
 200                         minimum_speed = speed;
 201                 if (speed > maximum_speed)
 202                         maximum_speed = speed;
 203
 204                 vid = *pst++;
 205                 powernow_table[j].driver_data |= (vid << 8); /* upper 8 bits */
 206
 207                 pr_debug("   FID: 0x%x (%d.%dx [%dMHz])  "
 208                          "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
 209                          fid_codes[fid] % 10, speed/1000, vid,
 210                          mobile_vid_table[vid]/1000,
 211                          mobile_vid_table[vid]%1000);
 212         }
 213         powernow_table[number_scales].frequency = CPUFREQ_TABLE_END;
 214         powernow_table[number_scales].driver_data = 0;
 215
 216         return 0;
 217 }
 218
 219
 220 static void change_FID(int fid)
 221 {
 222         union msr_fidvidctl fidvidctl;
 223
 224         rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 225         if (fidvidctl.bits.FID != fid) {
 226                 fidvidctl.bits.SGTC = latency;
 227                 fidvidctl.bits.FID = fid;
 228                 fidvidctl.bits.VIDC = 0;
 229                 fidvidctl.bits.FIDC = 1;
 230                 wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 231         }
 232 }
 233
 234
 235 static void change_VID(int vid)
 236 {
 237         union msr_fidvidctl fidvidctl;
 238
 239         rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 240         if (fidvidctl.bits.VID != vid) {
 241                 fidvidctl.bits.SGTC = latency;
 242                 fidvidctl.bits.VID = vid;
 243                 fidvidctl.bits.FIDC = 0;
 244                 fidvidctl.bits.VIDC = 1;
 245                 wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 246         }
 247 }
 248
 249
 250 static int powernow_target(struct cpufreq_policy *policy, unsigned int index)
 251 {
 252         u8 fid, vid;
 253         struct cpufreq_freqs freqs;
 254         union msr_fidvidstatus fidvidstatus;
 255         int cfid;
 256
 257         /* fid are the lower 8 bits of the index we stored into
 258          * the cpufreq frequency table in powernow_decode_bios,
 259          * vid are the upper 8 bits.
 260          */
 261
 262         fid = powernow_table[index].driver_data & 0xFF;
 263         vid = (powernow_table[index].driver_data & 0xFF00) >> 8;
 264
 265         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 266         cfid = fidvidstatus.bits.CFID;
 267         freqs.old = fsb * fid_codes[cfid] / 10;
 268
 269         freqs.new = powernow_table[index].frequency;
 270
 271         /* Now do the magic poking into the MSRs.  */
 272
 273         if (have_a0 == 1)       /* A0 errata 5 */
 274                 local_irq_disable();
 275
 276         if (freqs.old > freqs.new) {
 277                 /* Going down, so change FID first */
 278                 change_FID(fid);
 279                 change_VID(vid);
 280         } else {
 281                 /* Going up, so change VID first */
 282                 change_VID(vid);
 283                 change_FID(fid);
 284         }
 285
 286
 287         if (have_a0 == 1)
 288                 local_irq_enable();
 289
 290         return 0;
 291 }
 292
 293
 294 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 295
 296 static struct acpi_processor_performance *acpi_processor_perf;
 297
 298 static int powernow_acpi_init(void)
 299 {
 300         int i;
 301         int retval = 0;
 302         union powernow_acpi_control_t pc;
 303
 304         if (acpi_processor_perf != NULL && powernow_table != NULL) {
 305                 retval = -EINVAL;
 306                 goto err0;
 307         }
 308
 309         acpi_processor_perf = kzalloc(sizeof(*acpi_processor_perf), GFP_KERNEL);
 310         if (!acpi_processor_perf) {
 311                 retval = -ENOMEM;
 312                 goto err0;
 313         }
 314
 315         if (!zalloc_cpumask_var(&acpi_processor_perf->shared_cpu_map,
 316                                                                 GFP_KERNEL)) {
 317                 retval = -ENOMEM;
 318                 goto err05;
 319         }
 320
 321         if (acpi_processor_register_performance(acpi_processor_perf, 0)) {
 322                 retval = -EIO;
 323                 goto err1;
 324         }
 325
 326         if (acpi_processor_perf->control_register.space_id !=
 327                         ACPI_ADR_SPACE_FIXED_HARDWARE) {
 328                 retval = -ENODEV;
 329                 goto err2;
 330         }
 331
 332         if (acpi_processor_perf->status_register.space_id !=
 333                         ACPI_ADR_SPACE_FIXED_HARDWARE) {
 334                 retval = -ENODEV;
 335                 goto err2;
 336         }
 337
 338         number_scales = acpi_processor_perf->state_count;
 339
 340         if (number_scales < 2) {
 341                 retval = -ENODEV;
 342                 goto err2;
 343         }
 344
 345         powernow_table = kzalloc((sizeof(*powernow_table) *
 346                                 (number_scales + 1)), GFP_KERNEL);
 347         if (!powernow_table) {
 348                 retval = -ENOMEM;
 349                 goto err2;
 350         }
 351
 352         pc.val = (unsigned long) acpi_processor_perf->states[0].control;
 353         for (i = 0; i < number_scales; i++) {
 354                 u8 fid, vid;
 355                 struct acpi_processor_px *state =
 356                         &acpi_processor_perf->states[i];
 357                 unsigned int speed, speed_mhz;
 358
 359                 pc.val = (unsigned long) state->control;
 360                 pr_debug("acpi:  P%d: %d MHz %d mW %d uS control %08x SGTC %d\n",
 361                          i,
 362                          (u32) state->core_frequency,
 363                          (u32) state->power,
 364                          (u32) state->transition_latency,
 365                          (u32) state->control,
 366                          pc.bits.sgtc);
 367
 368                 vid = pc.bits.vid;
 369                 fid = pc.bits.fid;
 370
 371                 powernow_table[i].frequency = fsb * fid_codes[fid] / 10;
 372                 powernow_table[i].driver_data = fid; /* lower 8 bits */
 373                 powernow_table[i].driver_data |= (vid << 8); /* upper 8 bits */
 374
 375                 speed = powernow_table[i].frequency;
 376                 speed_mhz = speed / 1000;
 377
 378                 /* processor_perflib will multiply the MHz value by 1000 to
 379                  * get a KHz value (e.g. 1266000). However, powernow-k7 works
 380                  * with true KHz values (e.g. 1266768). To ensure that all
 381                  * powernow frequencies are available, we must ensure that
 382                  * ACPI doesn't restrict them, so we round up the MHz value
 383                  * to ensure that perflib's computed KHz value is greater than
 384                  * or equal to powernow's KHz value.
 385                  */
 386                 if (speed % 1000 > 0)
 387                         speed_mhz++;
 388
 389                 if ((fid_codes[fid] % 10) == 5) {
 390                         if (have_a0 == 1)
 391                                 invalidate_entry(i);
 392                 }
 393
 394                 pr_debug("   FID: 0x%x (%d.%dx [%dMHz])  "
 395                          "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
 396                          fid_codes[fid] % 10, speed_mhz, vid,
 397                          mobile_vid_table[vid]/1000,
 398                          mobile_vid_table[vid]%1000);
 399
 400                 if (state->core_frequency != speed_mhz) {
 401                         state->core_frequency = speed_mhz;
 402                         pr_debug("   Corrected ACPI frequency to %d\n",
 403                                 speed_mhz);
 404                 }
 405
 406                 if (latency < pc.bits.sgtc)
 407                         latency = pc.bits.sgtc;
 408
 409                 if (speed < minimum_speed)
 410                         minimum_speed = speed;
 411                 if (speed > maximum_speed)
 412                         maximum_speed = speed;
 413         }
 414
 415         powernow_table[i].frequency = CPUFREQ_TABLE_END;
 416         powernow_table[i].driver_data = 0;
 417
 418         /* notify BIOS that we exist */
 419         acpi_processor_notify_smm(THIS_MODULE);
 420
 421         return 0;
 422
 423 err2:
 424         acpi_processor_unregister_performance(acpi_processor_perf, 0);
 425 err1:
 426         free_cpumask_var(acpi_processor_perf->shared_cpu_map);
 427 err05:
 428         kfree(acpi_processor_perf);
 429 err0:
 430         printk(KERN_WARNING PFX "ACPI perflib can not be used on "
 431                         "this platform\n");
 432         acpi_processor_perf = NULL;
 433         return retval;
 434 }
 435 #else
 436 static int powernow_acpi_init(void)
 437 {
 438         printk(KERN_INFO PFX "no support for ACPI processor found."
 439                "  Please recompile your kernel with ACPI processor\n");
 440         return -EINVAL;
 441 }
 442 #endif
 443
 444 static void print_pst_entry(struct pst_s *pst, unsigned int j)
 445 {
 446         pr_debug("PST:%d (@%p)\n", j, pst);
 447         pr_debug(" cpuid: 0x%x  fsb: %d  maxFID: 0x%x  startvid: 0x%x\n",
 448                 pst->cpuid, pst->fsbspeed, pst->maxfid, pst->startvid);
 449 }
 450
 451 static int powernow_decode_bios(int maxfid, int startvid)
 452 {
 453         struct psb_s *psb;
 454         struct pst_s *pst;
 455         unsigned int i, j;
 456         unsigned char *p;
 457         unsigned int etuple;
 458         unsigned int ret;
 459
 460         etuple = cpuid_eax(0x80000001);
 461
 462         for (i = 0xC0000; i < 0xffff0 ; i += 16) {
 463
 464                 p = phys_to_virt(i);
 465
 466                 if (memcmp(p, "AMDK7PNOW!",  10) == 0) {
 467                         pr_debug("Found PSB header at %p\n", p);
 468                         psb = (struct psb_s *) p;
 469                         pr_debug("Table version: 0x%x\n", psb->tableversion);
 470                         if (psb->tableversion != 0x12) {
 471                                 printk(KERN_INFO PFX "Sorry, only v1.2 tables"
 472                                                 " supported right now\n");
 473                                 return -ENODEV;
 474                         }
 475
 476                         pr_debug("Flags: 0x%x\n", psb->flags);
 477                         if ((psb->flags & 1) == 0)
 478                                 pr_debug("Mobile voltage regulator\n");
 479                         else
 480                                 pr_debug("Desktop voltage regulator\n");
 481
 482                         latency = psb->settlingtime;
 483                         if (latency < 100) {
 484                                 printk(KERN_INFO PFX "BIOS set settling time "
 485                                                 "to %d microseconds. "
 486                                                 "Should be at least 100. "
 487                                                 "Correcting.\n", latency);
 488                                 latency = 100;
 489                         }
 490                         pr_debug("Settling Time: %d microseconds.\n",
 491                                         psb->settlingtime);
 492                         pr_debug("Has %d PST tables. (Only dumping ones "
 493                                         "relevant to this CPU).\n",
 494                                         psb->numpst);
 495
 496                         p += sizeof(*psb);
 497
 498                         pst = (struct pst_s *) p;
 499
 500                         for (j = 0; j < psb->numpst; j++) {
 501                                 pst = (struct pst_s *) p;
 502                                 number_scales = pst->numpstates;
 503
 504                                 if ((etuple == pst->cpuid) &&
 505                                     check_fsb(pst->fsbspeed) &&
 506                                     (maxfid == pst->maxfid) &&
 507                                     (startvid == pst->startvid)) {
 508                                         print_pst_entry(pst, j);
 509                                         p = (char *)pst + sizeof(*pst);
 510                                         ret = get_ranges(p);
 511                                         return ret;
 512                                 } else {
 513                                         unsigned int k;
 514                                         p = (char *)pst + sizeof(*pst);
 515                                         for (k = 0; k < number_scales; k++)
 516                                                 p += 2;
 517                                 }
 518                         }
 519                         printk(KERN_INFO PFX "No PST tables match this cpuid "
 520                                         "(0x%x)\n", etuple);
 521                         printk(KERN_INFO PFX "This is indicative of a broken "
 522                                         "BIOS.\n");
 523
 524                         return -EINVAL;
 525                 }
 526                 p++;
 527         }
 528
 529         return -ENODEV;
 530 }
 531
 532
 533 /*
 534  * We use the fact that the bus frequency is somehow
 535  * a multiple of 100000/3 khz, then we compute sgtc according
 536  * to this multiple.
 537  * That way, we match more how AMD thinks all of that work.
 538  * We will then get the same kind of behaviour already tested under
 539  * the "well-known" other OS.
 540  */
 541 static int fixup_sgtc(void)
 542 {
 543         unsigned int sgtc;
 544         unsigned int m;
 545
 546         m = fsb / 3333;
 547         if ((m % 10) >= 5)
 548                 m += 5;
 549
 550         m /= 10;
 551
 552         sgtc = 100 * m * latency;
 553         sgtc = sgtc / 3;
 554         if (sgtc > 0xfffff) {
 555                 printk(KERN_WARNING PFX "SGTC too large %d\n", sgtc);
 556                 sgtc = 0xfffff;
 557         }
 558         return sgtc;
 559 }
 560
 561 static unsigned int powernow_get(unsigned int cpu)
 562 {
 563         union msr_fidvidstatus fidvidstatus;
 564         unsigned int cfid;
 565
 566         if (cpu)
 567                 return 0;
 568         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 569         cfid = fidvidstatus.bits.CFID;
 570
 571         return fsb * fid_codes[cfid] / 10;
 572 }
 573
 574
 575 static int acer_cpufreq_pst(const struct dmi_system_id *d)
 576 {
 577         printk(KERN_WARNING PFX
 578                 "%s laptop with broken PST tables in BIOS detected.\n",
 579                 d->ident);
 580         printk(KERN_WARNING PFX
 581                 "You need to downgrade to 3A21 (09/09/2002), or try a newer "
 582                 "BIOS than 3A71 (01/20/2003)\n");
 583         printk(KERN_WARNING PFX
 584                 "cpufreq scaling has been disabled as a result of this.\n");
 585         return 0;
 586 }
 587
 588 /*
 589  * Some Athlon laptops have really fucked PST tables.
 590  * A BIOS update is all that can save them.
 591  * Mention this, and disable cpufreq.
 592  */
 593 static struct dmi_system_id powernow_dmi_table[] = {
 594         {
 595                 .callback = acer_cpufreq_pst,
 596                 .ident = "Acer Aspire",
 597                 .matches = {
 598                         DMI_MATCH(DMI_SYS_VENDOR, "Insyde Software"),
 599                         DMI_MATCH(DMI_BIOS_VERSION, "3A71"),
 600                 },
 601         },
 602         { }
 603 };
 604
 605 static int powernow_cpu_init(struct cpufreq_policy *policy)
 606 {
 607         union msr_fidvidstatus fidvidstatus;
 608         int result;
 609
 610         if (policy->cpu != 0)
 611                 return -ENODEV;
 612
 613         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 614
 615         recalibrate_cpu_khz();
 616
 617         fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.CFID];
 618         if (!fsb) {
 619                 printk(KERN_WARNING PFX "can not determine bus frequency\n");
 620                 return -EINVAL;
 621         }
 622         pr_debug("FSB: %3dMHz\n", fsb/1000);
 623
 624         if (dmi_check_system(powernow_dmi_table) || acpi_force) {
 625                 printk(KERN_INFO PFX "PSB/PST known to be broken.  "
 626                                 "Trying ACPI instead\n");
 627                 result = powernow_acpi_init();
 628         } else {
 629                 result = powernow_decode_bios(fidvidstatus.bits.MFID,
 630                                 fidvidstatus.bits.SVID);
 631                 if (result) {
 632                         printk(KERN_INFO PFX "Trying ACPI perflib\n");
 633                         maximum_speed = 0;
 634                         minimum_speed = -1;
 635                         latency = 0;
 636                         result = powernow_acpi_init();
 637                         if (result) {
 638                                 printk(KERN_INFO PFX
 639                                         "ACPI and legacy methods failed\n");
 640                         }
 641                 } else {
 642                         /* SGTC use the bus clock as timer */
 643                         latency = fixup_sgtc();
 644                         printk(KERN_INFO PFX "SGTC: %d\n", latency);
 645                 }
 646         }
 647
 648         if (result)
 649                 return result;
 650
 651         printk(KERN_INFO PFX "Minimum speed %d MHz. Maximum speed %d MHz.\n",
 652                                 minimum_speed/1000, maximum_speed/1000);
 653
 654         policy->cpuinfo.transition_latency =
 655                 cpufreq_scale(2000000UL, fsb, latency);
 656
 657         return cpufreq_table_validate_and_show(policy, powernow_table);
 658 }
 659
 660 static int powernow_cpu_exit(struct cpufreq_policy *policy)
 661 {
 662 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 663         if (acpi_processor_perf) {
 664                 acpi_processor_unregister_performance(acpi_processor_perf, 0);
 665                 free_cpumask_var(acpi_processor_perf->shared_cpu_map);
 666                 kfree(acpi_processor_perf);
 667         }
 668 #endif
 669
 670         kfree(powernow_table);
 671         return 0;
 672 }
 673
 674 static struct cpufreq_driver powernow_driver = {
 675         .verify         = cpufreq_generic_frequency_table_verify,
 676         .target_index   = powernow_target,
 677         .get            = powernow_get,
 678 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 679         .bios_limit     = acpi_processor_get_bios_limit,
 680 #endif
 681         .init           = powernow_cpu_init,
 682         .exit           = powernow_cpu_exit,
 683         .name           = "powernow-k7",
 684         .attr           = cpufreq_generic_attr,
 685 };
 686
 687 static int __init powernow_init(void)
 688 {
 689         if (check_powernow() == 0)
 690                 return -ENODEV;
 691         return cpufreq_register_driver(&powernow_driver);
 692 }
 693
 694
 695 static void __exit powernow_exit(void)
 696 {
 697         cpufreq_unregister_driver(&powernow_driver);
 698 }
 699
 700 module_param(acpi_force,  int, 0444);
 701 MODULE_PARM_DESC(acpi_force, "Force ACPI to be used.");
 702
 703 MODULE_AUTHOR("Dave Jones");
 704 MODULE_DESCRIPTION("Powernow driver for AMD K7 processors.");
 705 MODULE_LICENSE("GPL");
 706
 707 late_initcall(powernow_init);
 708 module_exit(powernow_exit);
 709