drivers/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/cpu_device_id.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 /* divide by 1000 to get VCore voltage in V. */
  72 static const int mobile_vid_table[32] = {
  73     2000, 1950, 1900, 1850, 1800, 1750, 1700, 1650,
  74     1600, 1550, 1500, 1450, 1400, 1350, 1300, 0,
  75     1275, 1250, 1225, 1200, 1175, 1150, 1125, 1100,
  76     1075, 1050, 1025, 1000, 975, 950, 925, 0,
  77 };
  78
  79 /* divide by 10 to get FID. */
  80 static const int fid_codes[32] = {
  81     110, 115, 120, 125, 50, 55, 60, 65,
  82     70, 75, 80, 85, 90, 95, 100, 105,
  83     30, 190, 40, 200, 130, 135, 140, 210,
  84     150, 225, 160, 165, 170, 180, -1, -1,
  85 };
  86
  87 /* This parameter is used in order to force ACPI instead of legacy method for
  88  * configuration purpose.
  89  */
  90
  91 static int acpi_force;
  92
  93 static struct cpufreq_frequency_table *powernow_table;
  94
  95 static unsigned int can_scale_bus;
  96 static unsigned int can_scale_vid;
  97 static unsigned int minimum_speed = -1;
  98 static unsigned int maximum_speed;
  99 static unsigned int number_scales;
 100 static unsigned int fsb;
 101 static unsigned int latency;
 102 static char have_a0;
 103
 104 static int check_fsb(unsigned int fsbspeed)
 105 {
 106         int delta;
 107         unsigned int f = fsb / 1000;
 108
 109         delta = (fsbspeed > f) ? fsbspeed - f : f - fsbspeed;
 110         return delta < 5;
 111 }
 112
 113 static const struct x86_cpu_id powernow_k7_cpuids[] = {
 114         { X86_VENDOR_AMD, 6, },
 115         {}
 116 };
 117 MODULE_DEVICE_TABLE(x86cpu, powernow_k7_cpuids);
 118
 119 static int check_powernow(void)
 120 {
 121         struct cpuinfo_x86 *c = &cpu_data(0);
 122         unsigned int maxei, eax, ebx, ecx, edx;
 123
 124         if (!x86_match_cpu(powernow_k7_cpuids))
 125                 return 0;
 126
 127         /* Get maximum capabilities */
 128         maxei = cpuid_eax(0x80000000);
 129         if (maxei < 0x80000007) {       /* Any powernow info ? */
 130 #ifdef MODULE
 131                 printk(KERN_INFO PFX "No powernow capabilities detected\n");
 132 #endif
 133                 return 0;
 134         }
 135
 136         if ((c->x86_model == 6) && (c->x86_mask == 0)) {
 137                 printk(KERN_INFO PFX "K7 660[A0] core detected, "
 138                                 "enabling errata workarounds\n");
 139                 have_a0 = 1;
 140         }
 141
 142         cpuid(0x80000007, &eax, &ebx, &ecx, &edx);
 143
 144         /* Check we can actually do something before we say anything.*/
 145         if (!(edx & (1 << 1 | 1 << 2)))
 146                 return 0;
 147
 148         printk(KERN_INFO PFX "PowerNOW! Technology present. Can scale: ");
 149
 150         if (edx & 1 << 1) {
 151                 printk("frequency");
 152                 can_scale_bus = 1;
 153         }
 154
 155         if ((edx & (1 << 1 | 1 << 2)) == 0x6)
 156                 printk(" and ");
 157
 158         if (edx & 1 << 2) {
 159                 printk("voltage");
 160                 can_scale_vid = 1;
 161         }
 162
 163         printk(".\n");
 164         return 1;
 165 }
 166
 167 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 168 static void invalidate_entry(unsigned int entry)
 169 {
 170         powernow_table[entry].frequency = CPUFREQ_ENTRY_INVALID;
 171 }
 172 #endif
 173
 174 static int get_ranges(unsigned char *pst)
 175 {
 176         unsigned int j;
 177         unsigned int speed;
 178         u8 fid, vid;
 179
 180         powernow_table = kzalloc((sizeof(struct cpufreq_frequency_table) *
 181                                 (number_scales + 1)), GFP_KERNEL);
 182         if (!powernow_table)
 183                 return -ENOMEM;
 184
 185         for (j = 0 ; j < number_scales; j++) {
 186                 fid = *pst++;
 187
 188                 powernow_table[j].frequency = (fsb * fid_codes[fid]) / 10;
 189                 powernow_table[j].index = fid; /* lower 8 bits */
 190
 191                 speed = powernow_table[j].frequency;
 192
 193                 if ((fid_codes[fid] % 10) == 5) {
 194 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 195                         if (have_a0 == 1)
 196                                 invalidate_entry(j);
 197 #endif
 198                 }
 199
 200                 if (speed < minimum_speed)
 201                         minimum_speed = speed;
 202                 if (speed > maximum_speed)
 203                         maximum_speed = speed;
 204
 205                 vid = *pst++;
 206                 powernow_table[j].index |= (vid << 8); /* upper 8 bits */
 207
 208                 pr_debug("   FID: 0x%x (%d.%dx [%dMHz])  "
 209                          "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
 210                          fid_codes[fid] % 10, speed/1000, vid,
 211                          mobile_vid_table[vid]/1000,
 212                          mobile_vid_table[vid]%1000);
 213         }
 214         powernow_table[number_scales].frequency = CPUFREQ_TABLE_END;
 215         powernow_table[number_scales].index = 0;
 216
 217         return 0;
 218 }
 219
 220
 221 static void change_FID(int fid)
 222 {
 223         union msr_fidvidctl fidvidctl;
 224
 225         rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 226         if (fidvidctl.bits.FID != fid) {
 227                 fidvidctl.bits.SGTC = latency;
 228                 fidvidctl.bits.FID = fid;
 229                 fidvidctl.bits.VIDC = 0;
 230                 fidvidctl.bits.FIDC = 1;
 231                 wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 232         }
 233 }
 234
 235
 236 static void change_VID(int vid)
 237 {
 238         union msr_fidvidctl fidvidctl;
 239
 240         rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 241         if (fidvidctl.bits.VID != vid) {
 242                 fidvidctl.bits.SGTC = latency;
 243                 fidvidctl.bits.VID = vid;
 244                 fidvidctl.bits.FIDC = 0;
 245                 fidvidctl.bits.VIDC = 1;
 246                 wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 247         }
 248 }
 249
 250
 251 static void change_speed(unsigned int index)
 252 {
 253         u8 fid, vid;
 254         struct cpufreq_freqs freqs;
 255         union msr_fidvidstatus fidvidstatus;
 256         int cfid;
 257
 258         /* fid are the lower 8 bits of the index we stored into
 259          * the cpufreq frequency table in powernow_decode_bios,
 260          * vid are the upper 8 bits.
 261          */
 262
 263         fid = powernow_table[index].index & 0xFF;
 264         vid = (powernow_table[index].index & 0xFF00) >> 8;
 265
 266         freqs.cpu = 0;
 267
 268         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 269         cfid = fidvidstatus.bits.CFID;
 270         freqs.old = fsb * fid_codes[cfid] / 10;
 271
 272         freqs.new = powernow_table[index].frequency;
 273
 274         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 275
 276         /* Now do the magic poking into the MSRs.  */
 277
 278         if (have_a0 == 1)       /* A0 errata 5 */
 279                 local_irq_disable();
 280
 281         if (freqs.old > freqs.new) {
 282                 /* Going down, so change FID first */
 283                 change_FID(fid);
 284                 change_VID(vid);
 285         } else {
 286                 /* Going up, so change VID first */
 287                 change_VID(vid);
 288                 change_FID(fid);
 289         }
 290
 291
 292         if (have_a0 == 1)
 293                 local_irq_enable();
 294
 295         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 296 }
 297
 298
 299 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 300
 301 static struct acpi_processor_performance *acpi_processor_perf;
 302
 303 static int powernow_acpi_init(void)
 304 {
 305         int i;
 306         int retval = 0;
 307         union powernow_acpi_control_t pc;
 308
 309         if (acpi_processor_perf != NULL && powernow_table != NULL) {
 310                 retval = -EINVAL;
 311                 goto err0;
 312         }
 313
 314         acpi_processor_perf = kzalloc(sizeof(struct acpi_processor_performance),
 315                                       GFP_KERNEL);
 316         if (!acpi_processor_perf) {
 317                 retval = -ENOMEM;
 318                 goto err0;
 319         }
 320
 321         if (!zalloc_cpumask_var(&acpi_processor_perf->shared_cpu_map,
 322                                                                 GFP_KERNEL)) {
 323                 retval = -ENOMEM;
 324                 goto err05;
 325         }
 326
 327         if (acpi_processor_register_performance(acpi_processor_perf, 0)) {
 328                 retval = -EIO;
 329                 goto err1;
 330         }
 331
 332         if (acpi_processor_perf->control_register.space_id !=
 333                         ACPI_ADR_SPACE_FIXED_HARDWARE) {
 334                 retval = -ENODEV;
 335                 goto err2;
 336         }
 337
 338         if (acpi_processor_perf->status_register.space_id !=
 339                         ACPI_ADR_SPACE_FIXED_HARDWARE) {
 340                 retval = -ENODEV;
 341                 goto err2;
 342         }
 343
 344         number_scales = acpi_processor_perf->state_count;
 345
 346         if (number_scales < 2) {
 347                 retval = -ENODEV;
 348                 goto err2;
 349         }
 350
 351         powernow_table = kzalloc((sizeof(struct cpufreq_frequency_table) *
 352                                 (number_scales + 1)), GFP_KERNEL);
 353         if (!powernow_table) {
 354                 retval = -ENOMEM;
 355                 goto err2;
 356         }
 357
 358         pc.val = (unsigned long) acpi_processor_perf->states[0].control;
 359         for (i = 0; i < number_scales; i++) {
 360                 u8 fid, vid;
 361                 struct acpi_processor_px *state =
 362                         &acpi_processor_perf->states[i];
 363                 unsigned int speed, speed_mhz;
 364
 365                 pc.val = (unsigned long) state->control;
 366                 pr_debug("acpi:  P%d: %d MHz %d mW %d uS control %08x SGTC %d\n",
 367                          i,
 368                          (u32) state->core_frequency,
 369                          (u32) state->power,
 370                          (u32) state->transition_latency,
 371                          (u32) state->control,
 372                          pc.bits.sgtc);
 373
 374                 vid = pc.bits.vid;
 375                 fid = pc.bits.fid;
 376
 377                 powernow_table[i].frequency = fsb * fid_codes[fid] / 10;
 378                 powernow_table[i].index = fid; /* lower 8 bits */
 379                 powernow_table[i].index |= (vid << 8); /* upper 8 bits */
 380
 381                 speed = powernow_table[i].frequency;
 382                 speed_mhz = speed / 1000;
 383
 384                 /* processor_perflib will multiply the MHz value by 1000 to
 385                  * get a KHz value (e.g. 1266000). However, powernow-k7 works
 386                  * with true KHz values (e.g. 1266768). To ensure that all
 387                  * powernow frequencies are available, we must ensure that
 388                  * ACPI doesn't restrict them, so we round up the MHz value
 389                  * to ensure that perflib's computed KHz value is greater than
 390                  * or equal to powernow's KHz value.
 391                  */
 392                 if (speed % 1000 > 0)
 393                         speed_mhz++;
 394
 395                 if ((fid_codes[fid] % 10) == 5) {
 396                         if (have_a0 == 1)
 397                                 invalidate_entry(i);
 398                 }
 399
 400                 pr_debug("   FID: 0x%x (%d.%dx [%dMHz])  "
 401                          "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
 402                          fid_codes[fid] % 10, speed_mhz, vid,
 403                          mobile_vid_table[vid]/1000,
 404                          mobile_vid_table[vid]%1000);
 405
 406                 if (state->core_frequency != speed_mhz) {
 407                         state->core_frequency = speed_mhz;
 408                         pr_debug("   Corrected ACPI frequency to %d\n",
 409                                 speed_mhz);
 410                 }
 411
 412                 if (latency < pc.bits.sgtc)
 413                         latency = pc.bits.sgtc;
 414
 415                 if (speed < minimum_speed)
 416                         minimum_speed = speed;
 417                 if (speed > maximum_speed)
 418                         maximum_speed = speed;
 419         }
 420
 421         powernow_table[i].frequency = CPUFREQ_TABLE_END;
 422         powernow_table[i].index = 0;
 423
 424         /* notify BIOS that we exist */
 425         acpi_processor_notify_smm(THIS_MODULE);
 426
 427         return 0;
 428
 429 err2:
 430         acpi_processor_unregister_performance(acpi_processor_perf, 0);
 431 err1:
 432         free_cpumask_var(acpi_processor_perf->shared_cpu_map);
 433 err05:
 434         kfree(acpi_processor_perf);
 435 err0:
 436         printk(KERN_WARNING PFX "ACPI perflib can not be used on "
 437                         "this platform\n");
 438         acpi_processor_perf = NULL;
 439         return retval;
 440 }
 441 #else
 442 static int powernow_acpi_init(void)
 443 {
 444         printk(KERN_INFO PFX "no support for ACPI processor found."
 445                "  Please recompile your kernel with ACPI processor\n");
 446         return -EINVAL;
 447 }
 448 #endif
 449
 450 static void print_pst_entry(struct pst_s *pst, unsigned int j)
 451 {
 452         pr_debug("PST:%d (@%p)\n", j, pst);
 453         pr_debug(" cpuid: 0x%x  fsb: %d  maxFID: 0x%x  startvid: 0x%x\n",
 454                 pst->cpuid, pst->fsbspeed, pst->maxfid, pst->startvid);
 455 }
 456
 457 static int powernow_decode_bios(int maxfid, int startvid)
 458 {
 459         struct psb_s *psb;
 460         struct pst_s *pst;
 461         unsigned int i, j;
 462         unsigned char *p;
 463         unsigned int etuple;
 464         unsigned int ret;
 465
 466         etuple = cpuid_eax(0x80000001);
 467
 468         for (i = 0xC0000; i < 0xffff0 ; i += 16) {
 469
 470                 p = phys_to_virt(i);
 471
 472                 if (memcmp(p, "AMDK7PNOW!",  10) == 0) {
 473                         pr_debug("Found PSB header at %p\n", p);
 474                         psb = (struct psb_s *) p;
 475                         pr_debug("Table version: 0x%x\n", psb->tableversion);
 476                         if (psb->tableversion != 0x12) {
 477                                 printk(KERN_INFO PFX "Sorry, only v1.2 tables"
 478                                                 " supported right now\n");
 479                                 return -ENODEV;
 480                         }
 481
 482                         pr_debug("Flags: 0x%x\n", psb->flags);
 483                         if ((psb->flags & 1) == 0)
 484                                 pr_debug("Mobile voltage regulator\n");
 485                         else
 486                                 pr_debug("Desktop voltage regulator\n");
 487
 488                         latency = psb->settlingtime;
 489                         if (latency < 100) {
 490                                 printk(KERN_INFO PFX "BIOS set settling time "
 491                                                 "to %d microseconds. "
 492                                                 "Should be at least 100. "
 493                                                 "Correcting.\n", latency);
 494                                 latency = 100;
 495                         }
 496                         pr_debug("Settling Time: %d microseconds.\n",
 497                                         psb->settlingtime);
 498                         pr_debug("Has %d PST tables. (Only dumping ones "
 499                                         "relevant to this CPU).\n",
 500                                         psb->numpst);
 501
 502                         p += sizeof(struct psb_s);
 503
 504                         pst = (struct pst_s *) p;
 505
 506                         for (j = 0; j < psb->numpst; j++) {
 507                                 pst = (struct pst_s *) p;
 508                                 number_scales = pst->numpstates;
 509
 510                                 if ((etuple == pst->cpuid) &&
 511                                     check_fsb(pst->fsbspeed) &&
 512                                     (maxfid == pst->maxfid) &&
 513                                     (startvid == pst->startvid)) {
 514                                         print_pst_entry(pst, j);
 515                                         p = (char *)pst + sizeof(struct pst_s);
 516                                         ret = get_ranges(p);
 517                                         return ret;
 518                                 } else {
 519                                         unsigned int k;
 520                                         p = (char *)pst + sizeof(struct pst_s);
 521                                         for (k = 0; k < number_scales; k++)
 522                                                 p += 2;
 523                                 }
 524                         }
 525                         printk(KERN_INFO PFX "No PST tables match this cpuid "
 526                                         "(0x%x)\n", etuple);
 527                         printk(KERN_INFO PFX "This is indicative of a broken "
 528                                         "BIOS.\n");
 529
 530                         return -EINVAL;
 531                 }
 532                 p++;
 533         }
 534
 535         return -ENODEV;
 536 }
 537
 538
 539 static int powernow_target(struct cpufreq_policy *policy,
 540                             unsigned int target_freq,
 541                             unsigned int relation)
 542 {
 543         unsigned int newstate;
 544
 545         if (cpufreq_frequency_table_target(policy, powernow_table, target_freq,
 546                                 relation, &newstate))
 547                 return -EINVAL;
 548
 549         change_speed(newstate);
 550
 551         return 0;
 552 }
 553
 554
 555 static int powernow_verify(struct cpufreq_policy *policy)
 556 {
 557         return cpufreq_frequency_table_verify(policy, powernow_table);
 558 }
 559
 560 /*
 561  * We use the fact that the bus frequency is somehow
 562  * a multiple of 100000/3 khz, then we compute sgtc according
 563  * to this multiple.
 564  * That way, we match more how AMD thinks all of that work.
 565  * We will then get the same kind of behaviour already tested under
 566  * the "well-known" other OS.
 567  */
 568 static int __cpuinit fixup_sgtc(void)
 569 {
 570         unsigned int sgtc;
 571         unsigned int m;
 572
 573         m = fsb / 3333;
 574         if ((m % 10) >= 5)
 575                 m += 5;
 576
 577         m /= 10;
 578
 579         sgtc = 100 * m * latency;
 580         sgtc = sgtc / 3;
 581         if (sgtc > 0xfffff) {
 582                 printk(KERN_WARNING PFX "SGTC too large %d\n", sgtc);
 583                 sgtc = 0xfffff;
 584         }
 585         return sgtc;
 586 }
 587
 588 static unsigned int powernow_get(unsigned int cpu)
 589 {
 590         union msr_fidvidstatus fidvidstatus;
 591         unsigned int cfid;
 592
 593         if (cpu)
 594                 return 0;
 595         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 596         cfid = fidvidstatus.bits.CFID;
 597
 598         return fsb * fid_codes[cfid] / 10;
 599 }
 600
 601
 602 static int __cpuinit acer_cpufreq_pst(const struct dmi_system_id *d)
 603 {
 604         printk(KERN_WARNING PFX
 605                 "%s laptop with broken PST tables in BIOS detected.\n",
 606                 d->ident);
 607         printk(KERN_WARNING PFX
 608                 "You need to downgrade to 3A21 (09/09/2002), or try a newer "
 609                 "BIOS than 3A71 (01/20/2003)\n");
 610         printk(KERN_WARNING PFX
 611                 "cpufreq scaling has been disabled as a result of this.\n");
 612         return 0;
 613 }
 614
 615 /*
 616  * Some Athlon laptops have really fucked PST tables.
 617  * A BIOS update is all that can save them.
 618  * Mention this, and disable cpufreq.
 619  */
 620 static struct dmi_system_id __cpuinitdata powernow_dmi_table[] = {
 621         {
 622                 .callback = acer_cpufreq_pst,
 623                 .ident = "Acer Aspire",
 624                 .matches = {
 625                         DMI_MATCH(DMI_SYS_VENDOR, "Insyde Software"),
 626                         DMI_MATCH(DMI_BIOS_VERSION, "3A71"),
 627                 },
 628         },
 629         { }
 630 };
 631
 632 static int __cpuinit powernow_cpu_init(struct cpufreq_policy *policy)
 633 {
 634         union msr_fidvidstatus fidvidstatus;
 635         int result;
 636
 637         if (policy->cpu != 0)
 638                 return -ENODEV;
 639
 640         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 641
 642         recalibrate_cpu_khz();
 643
 644         fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.CFID];
 645         if (!fsb) {
 646                 printk(KERN_WARNING PFX "can not determine bus frequency\n");
 647                 return -EINVAL;
 648         }
 649         pr_debug("FSB: %3dMHz\n", fsb/1000);
 650
 651         if (dmi_check_system(powernow_dmi_table) || acpi_force) {
 652                 printk(KERN_INFO PFX "PSB/PST known to be broken.  "
 653                                 "Trying ACPI instead\n");
 654                 result = powernow_acpi_init();
 655         } else {
 656                 result = powernow_decode_bios(fidvidstatus.bits.MFID,
 657                                 fidvidstatus.bits.SVID);
 658                 if (result) {
 659                         printk(KERN_INFO PFX "Trying ACPI perflib\n");
 660                         maximum_speed = 0;
 661                         minimum_speed = -1;
 662                         latency = 0;
 663                         result = powernow_acpi_init();
 664                         if (result) {
 665                                 printk(KERN_INFO PFX
 666                                         "ACPI and legacy methods failed\n");
 667                         }
 668                 } else {
 669                         /* SGTC use the bus clock as timer */
 670                         latency = fixup_sgtc();
 671                         printk(KERN_INFO PFX "SGTC: %d\n", latency);
 672                 }
 673         }
 674
 675         if (result)
 676                 return result;
 677
 678         printk(KERN_INFO PFX "Minimum speed %d MHz. Maximum speed %d MHz.\n",
 679                                 minimum_speed/1000, maximum_speed/1000);
 680
 681         policy->cpuinfo.transition_latency =
 682                 cpufreq_scale(2000000UL, fsb, latency);
 683
 684         policy->cur = powernow_get(0);
 685
 686         cpufreq_frequency_table_get_attr(powernow_table, policy->cpu);
 687
 688         return cpufreq_frequency_table_cpuinfo(policy, powernow_table);
 689 }
 690
 691 static int powernow_cpu_exit(struct cpufreq_policy *policy)
 692 {
 693         cpufreq_frequency_table_put_attr(policy->cpu);
 694
 695 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 696         if (acpi_processor_perf) {
 697                 acpi_processor_unregister_performance(acpi_processor_perf, 0);
 698                 free_cpumask_var(acpi_processor_perf->shared_cpu_map);
 699                 kfree(acpi_processor_perf);
 700         }
 701 #endif
 702
 703         kfree(powernow_table);
 704         return 0;
 705 }
 706
 707 static struct freq_attr *powernow_table_attr[] = {
 708         &cpufreq_freq_attr_scaling_available_freqs,
 709         NULL,
 710 };
 711
 712 static struct cpufreq_driver powernow_driver = {
 713         .verify         = powernow_verify,
 714         .target         = powernow_target,
 715         .get            = powernow_get,
 716 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 717         .bios_limit     = acpi_processor_get_bios_limit,
 718 #endif
 719         .init           = powernow_cpu_init,
 720         .exit           = powernow_cpu_exit,
 721         .name           = "powernow-k7",
 722         .owner          = THIS_MODULE,
 723         .attr           = powernow_table_attr,
 724 };
 725
 726 static int __init powernow_init(void)
 727 {
 728         if (check_powernow() == 0)
 729                 return -ENODEV;
 730         return cpufreq_register_driver(&powernow_driver);
 731 }
 732
 733
 734 static void __exit powernow_exit(void)
 735 {
 736         cpufreq_unregister_driver(&powernow_driver);
 737 }
 738
 739 module_param(acpi_force,  int, 0444);
 740 MODULE_PARM_DESC(acpi_force, "Force ACPI to be used.");
 741
 742 MODULE_AUTHOR("Dave Jones <davej@redhat.com>");
 743 MODULE_DESCRIPTION("Powernow driver for AMD K7 processors.");
 744 MODULE_LICENSE("GPL");
 745
 746 late_initcall(powernow_init);
 747 module_exit(powernow_exit);
 748