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 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 172 static void invalidate_entry(unsigned int entry)
 173 {
 174         powernow_table[entry].frequency = CPUFREQ_ENTRY_INVALID;
 175 }
 176 #endif
 177
 178 static int get_ranges(unsigned char *pst)
 179 {
 180         unsigned int j;
 181         unsigned int speed;
 182         u8 fid, vid;
 183
 184         powernow_table = kzalloc((sizeof(struct cpufreq_frequency_table) *
 185                                 (number_scales + 1)), GFP_KERNEL);
 186         if (!powernow_table)
 187                 return -ENOMEM;
 188
 189         for (j = 0 ; j < number_scales; j++) {
 190                 fid = *pst++;
 191
 192                 powernow_table[j].frequency = (fsb * fid_codes[fid]) / 10;
 193                 powernow_table[j].index = fid; /* lower 8 bits */
 194
 195                 speed = powernow_table[j].frequency;
 196
 197                 if ((fid_codes[fid] % 10) == 5) {
 198 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 199                         if (have_a0 == 1)
 200                                 invalidate_entry(j);
 201 #endif
 202                 }
 203
 204                 if (speed < minimum_speed)
 205                         minimum_speed = speed;
 206                 if (speed > maximum_speed)
 207                         maximum_speed = speed;
 208
 209                 vid = *pst++;
 210                 powernow_table[j].index |= (vid << 8); /* upper 8 bits */
 211
 212                 dprintk("   FID: 0x%x (%d.%dx [%dMHz])  "
 213                          "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
 214                          fid_codes[fid] % 10, speed/1000, vid,
 215                          mobile_vid_table[vid]/1000,
 216                          mobile_vid_table[vid]%1000);
 217         }
 218         powernow_table[number_scales].frequency = CPUFREQ_TABLE_END;
 219         powernow_table[number_scales].index = 0;
 220
 221         return 0;
 222 }
 223
 224
 225 static void change_FID(int fid)
 226 {
 227         union msr_fidvidctl fidvidctl;
 228
 229         rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 230         if (fidvidctl.bits.FID != fid) {
 231                 fidvidctl.bits.SGTC = latency;
 232                 fidvidctl.bits.FID = fid;
 233                 fidvidctl.bits.VIDC = 0;
 234                 fidvidctl.bits.FIDC = 1;
 235                 wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 236         }
 237 }
 238
 239
 240 static void change_VID(int vid)
 241 {
 242         union msr_fidvidctl fidvidctl;
 243
 244         rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 245         if (fidvidctl.bits.VID != vid) {
 246                 fidvidctl.bits.SGTC = latency;
 247                 fidvidctl.bits.VID = vid;
 248                 fidvidctl.bits.FIDC = 0;
 249                 fidvidctl.bits.VIDC = 1;
 250                 wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 251         }
 252 }
 253
 254
 255 static void change_speed(unsigned int index)
 256 {
 257         u8 fid, vid;
 258         struct cpufreq_freqs freqs;
 259         union msr_fidvidstatus fidvidstatus;
 260         int cfid;
 261
 262         /* fid are the lower 8 bits of the index we stored into
 263          * the cpufreq frequency table in powernow_decode_bios,
 264          * vid are the upper 8 bits.
 265          */
 266
 267         fid = powernow_table[index].index & 0xFF;
 268         vid = (powernow_table[index].index & 0xFF00) >> 8;
 269
 270         freqs.cpu = 0;
 271
 272         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 273         cfid = fidvidstatus.bits.CFID;
 274         freqs.old = fsb * fid_codes[cfid] / 10;
 275
 276         freqs.new = powernow_table[index].frequency;
 277
 278         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 279
 280         /* Now do the magic poking into the MSRs.  */
 281
 282         if (have_a0 == 1)       /* A0 errata 5 */
 283                 local_irq_disable();
 284
 285         if (freqs.old > freqs.new) {
 286                 /* Going down, so change FID first */
 287                 change_FID(fid);
 288                 change_VID(vid);
 289         } else {
 290                 /* Going up, so change VID first */
 291                 change_VID(vid);
 292                 change_FID(fid);
 293         }
 294
 295
 296         if (have_a0 == 1)
 297                 local_irq_enable();
 298
 299         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 300 }
 301
 302
 303 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 304
 305 static struct acpi_processor_performance *acpi_processor_perf;
 306
 307 static int powernow_acpi_init(void)
 308 {
 309         int i;
 310         int retval = 0;
 311         union powernow_acpi_control_t pc;
 312
 313         if (acpi_processor_perf != NULL && powernow_table != NULL) {
 314                 retval = -EINVAL;
 315                 goto err0;
 316         }
 317
 318         acpi_processor_perf = kzalloc(sizeof(struct acpi_processor_performance),
 319                                       GFP_KERNEL);
 320         if (!acpi_processor_perf) {
 321                 retval = -ENOMEM;
 322                 goto err0;
 323         }
 324
 325         if (!zalloc_cpumask_var(&acpi_processor_perf->shared_cpu_map,
 326                                                                 GFP_KERNEL)) {
 327                 retval = -ENOMEM;
 328                 goto err05;
 329         }
 330
 331         if (acpi_processor_register_performance(acpi_processor_perf, 0)) {
 332                 retval = -EIO;
 333                 goto err1;
 334         }
 335
 336         if (acpi_processor_perf->control_register.space_id !=
 337                         ACPI_ADR_SPACE_FIXED_HARDWARE) {
 338                 retval = -ENODEV;
 339                 goto err2;
 340         }
 341
 342         if (acpi_processor_perf->status_register.space_id !=
 343                         ACPI_ADR_SPACE_FIXED_HARDWARE) {
 344                 retval = -ENODEV;
 345                 goto err2;
 346         }
 347
 348         number_scales = acpi_processor_perf->state_count;
 349
 350         if (number_scales < 2) {
 351                 retval = -ENODEV;
 352                 goto err2;
 353         }
 354
 355         powernow_table = kzalloc((sizeof(struct cpufreq_frequency_table) *
 356                                 (number_scales + 1)), GFP_KERNEL);
 357         if (!powernow_table) {
 358                 retval = -ENOMEM;
 359                 goto err2;
 360         }
 361
 362         pc.val = (unsigned long) acpi_processor_perf->states[0].control;
 363         for (i = 0; i < number_scales; i++) {
 364                 u8 fid, vid;
 365                 struct acpi_processor_px *state =
 366                         &acpi_processor_perf->states[i];
 367                 unsigned int speed, speed_mhz;
 368
 369                 pc.val = (unsigned long) state->control;
 370                 dprintk("acpi:  P%d: %d MHz %d mW %d uS control %08x SGTC %d\n",
 371                          i,
 372                          (u32) state->core_frequency,
 373                          (u32) state->power,
 374                          (u32) state->transition_latency,
 375                          (u32) state->control,
 376                          pc.bits.sgtc);
 377
 378                 vid = pc.bits.vid;
 379                 fid = pc.bits.fid;
 380
 381                 powernow_table[i].frequency = fsb * fid_codes[fid] / 10;
 382                 powernow_table[i].index = fid; /* lower 8 bits */
 383                 powernow_table[i].index |= (vid << 8); /* upper 8 bits */
 384
 385                 speed = powernow_table[i].frequency;
 386                 speed_mhz = speed / 1000;
 387
 388                 /* processor_perflib will multiply the MHz value by 1000 to
 389                  * get a KHz value (e.g. 1266000). However, powernow-k7 works
 390                  * with true KHz values (e.g. 1266768). To ensure that all
 391                  * powernow frequencies are available, we must ensure that
 392                  * ACPI doesn't restrict them, so we round up the MHz value
 393                  * to ensure that perflib's computed KHz value is greater than
 394                  * or equal to powernow's KHz value.
 395                  */
 396                 if (speed % 1000 > 0)
 397                         speed_mhz++;
 398
 399                 if ((fid_codes[fid] % 10) == 5) {
 400                         if (have_a0 == 1)
 401                                 invalidate_entry(i);
 402                 }
 403
 404                 dprintk("   FID: 0x%x (%d.%dx [%dMHz])  "
 405                          "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
 406                          fid_codes[fid] % 10, speed_mhz, vid,
 407                          mobile_vid_table[vid]/1000,
 408                          mobile_vid_table[vid]%1000);
 409
 410                 if (state->core_frequency != speed_mhz) {
 411                         state->core_frequency = speed_mhz;
 412                         dprintk("   Corrected ACPI frequency to %d\n",
 413                                 speed_mhz);
 414                 }
 415
 416                 if (latency < pc.bits.sgtc)
 417                         latency = pc.bits.sgtc;
 418
 419                 if (speed < minimum_speed)
 420                         minimum_speed = speed;
 421                 if (speed > maximum_speed)
 422                         maximum_speed = speed;
 423         }
 424
 425         powernow_table[i].frequency = CPUFREQ_TABLE_END;
 426         powernow_table[i].index = 0;
 427
 428         /* notify BIOS that we exist */
 429         acpi_processor_notify_smm(THIS_MODULE);
 430
 431         return 0;
 432
 433 err2:
 434         acpi_processor_unregister_performance(acpi_processor_perf, 0);
 435 err1:
 436         free_cpumask_var(acpi_processor_perf->shared_cpu_map);
 437 err05:
 438         kfree(acpi_processor_perf);
 439 err0:
 440         printk(KERN_WARNING PFX "ACPI perflib can not be used on "
 441                         "this platform\n");
 442         acpi_processor_perf = NULL;
 443         return retval;
 444 }
 445 #else
 446 static int powernow_acpi_init(void)
 447 {
 448         printk(KERN_INFO PFX "no support for ACPI processor found."
 449                "  Please recompile your kernel with ACPI processor\n");
 450         return -EINVAL;
 451 }
 452 #endif
 453
 454 static void print_pst_entry(struct pst_s *pst, unsigned int j)
 455 {
 456         dprintk("PST:%d (@%p)\n", j, pst);
 457         dprintk(" cpuid: 0x%x  fsb: %d  maxFID: 0x%x  startvid: 0x%x\n",
 458                 pst->cpuid, pst->fsbspeed, pst->maxfid, pst->startvid);
 459 }
 460
 461 static int powernow_decode_bios(int maxfid, int startvid)
 462 {
 463         struct psb_s *psb;
 464         struct pst_s *pst;
 465         unsigned int i, j;
 466         unsigned char *p;
 467         unsigned int etuple;
 468         unsigned int ret;
 469
 470         etuple = cpuid_eax(0x80000001);
 471
 472         for (i = 0xC0000; i < 0xffff0 ; i += 16) {
 473
 474                 p = phys_to_virt(i);
 475
 476                 if (memcmp(p, "AMDK7PNOW!",  10) == 0) {
 477                         dprintk("Found PSB header at %p\n", p);
 478                         psb = (struct psb_s *) p;
 479                         dprintk("Table version: 0x%x\n", psb->tableversion);
 480                         if (psb->tableversion != 0x12) {
 481                                 printk(KERN_INFO PFX "Sorry, only v1.2 tables"
 482                                                 " supported right now\n");
 483                                 return -ENODEV;
 484                         }
 485
 486                         dprintk("Flags: 0x%x\n", psb->flags);
 487                         if ((psb->flags & 1) == 0)
 488                                 dprintk("Mobile voltage regulator\n");
 489                         else
 490                                 dprintk("Desktop voltage regulator\n");
 491
 492                         latency = psb->settlingtime;
 493                         if (latency < 100) {
 494                                 printk(KERN_INFO PFX "BIOS set settling time "
 495                                                 "to %d microseconds. "
 496                                                 "Should be at least 100. "
 497                                                 "Correcting.\n", latency);
 498                                 latency = 100;
 499                         }
 500                         dprintk("Settling Time: %d microseconds.\n",
 501                                         psb->settlingtime);
 502                         dprintk("Has %d PST tables. (Only dumping ones "
 503                                         "relevant to this CPU).\n",
 504                                         psb->numpst);
 505
 506                         p += sizeof(struct psb_s);
 507
 508                         pst = (struct pst_s *) p;
 509
 510                         for (j = 0; j < psb->numpst; j++) {
 511                                 pst = (struct pst_s *) p;
 512                                 number_scales = pst->numpstates;
 513
 514                                 if ((etuple == pst->cpuid) &&
 515                                     check_fsb(pst->fsbspeed) &&
 516                                     (maxfid == pst->maxfid) &&
 517                                     (startvid == pst->startvid)) {
 518                                         print_pst_entry(pst, j);
 519                                         p = (char *)pst + sizeof(struct pst_s);
 520                                         ret = get_ranges(p);
 521                                         return ret;
 522                                 } else {
 523                                         unsigned int k;
 524                                         p = (char *)pst + sizeof(struct pst_s);
 525                                         for (k = 0; k < number_scales; k++)
 526                                                 p += 2;
 527                                 }
 528                         }
 529                         printk(KERN_INFO PFX "No PST tables match this cpuid "
 530                                         "(0x%x)\n", etuple);
 531                         printk(KERN_INFO PFX "This is indicative of a broken "
 532                                         "BIOS.\n");
 533
 534                         return -EINVAL;
 535                 }
 536                 p++;
 537         }
 538
 539         return -ENODEV;
 540 }
 541
 542
 543 static int powernow_target(struct cpufreq_policy *policy,
 544                             unsigned int target_freq,
 545                             unsigned int relation)
 546 {
 547         unsigned int newstate;
 548
 549         if (cpufreq_frequency_table_target(policy, powernow_table, target_freq,
 550                                 relation, &newstate))
 551                 return -EINVAL;
 552
 553         change_speed(newstate);
 554
 555         return 0;
 556 }
 557
 558
 559 static int powernow_verify(struct cpufreq_policy *policy)
 560 {
 561         return cpufreq_frequency_table_verify(policy, powernow_table);
 562 }
 563
 564 /*
 565  * We use the fact that the bus frequency is somehow
 566  * a multiple of 100000/3 khz, then we compute sgtc according
 567  * to this multiple.
 568  * That way, we match more how AMD thinks all of that work.
 569  * We will then get the same kind of behaviour already tested under
 570  * the "well-known" other OS.
 571  */
 572 static int __init fixup_sgtc(void)
 573 {
 574         unsigned int sgtc;
 575         unsigned int m;
 576
 577         m = fsb / 3333;
 578         if ((m % 10) >= 5)
 579                 m += 5;
 580
 581         m /= 10;
 582
 583         sgtc = 100 * m * latency;
 584         sgtc = sgtc / 3;
 585         if (sgtc > 0xfffff) {
 586                 printk(KERN_WARNING PFX "SGTC too large %d\n", sgtc);
 587                 sgtc = 0xfffff;
 588         }
 589         return sgtc;
 590 }
 591
 592 static unsigned int powernow_get(unsigned int cpu)
 593 {
 594         union msr_fidvidstatus fidvidstatus;
 595         unsigned int cfid;
 596
 597         if (cpu)
 598                 return 0;
 599         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 600         cfid = fidvidstatus.bits.CFID;
 601
 602         return fsb * fid_codes[cfid] / 10;
 603 }
 604
 605
 606 static int __init acer_cpufreq_pst(const struct dmi_system_id *d)
 607 {
 608         printk(KERN_WARNING PFX
 609                 "%s laptop with broken PST tables in BIOS detected.\n",
 610                 d->ident);
 611         printk(KERN_WARNING PFX
 612                 "You need to downgrade to 3A21 (09/09/2002), or try a newer "
 613                 "BIOS than 3A71 (01/20/2003)\n");
 614         printk(KERN_WARNING PFX
 615                 "cpufreq scaling has been disabled as a result of this.\n");
 616         return 0;
 617 }
 618
 619 /*
 620  * Some Athlon laptops have really fucked PST tables.
 621  * A BIOS update is all that can save them.
 622  * Mention this, and disable cpufreq.
 623  */
 624 static struct dmi_system_id __initdata powernow_dmi_table[] = {
 625         {
 626                 .callback = acer_cpufreq_pst,
 627                 .ident = "Acer Aspire",
 628                 .matches = {
 629                         DMI_MATCH(DMI_SYS_VENDOR, "Insyde Software"),
 630                         DMI_MATCH(DMI_BIOS_VERSION, "3A71"),
 631                 },
 632         },
 633         { }
 634 };
 635
 636 static int __init powernow_cpu_init(struct cpufreq_policy *policy)
 637 {
 638         union msr_fidvidstatus fidvidstatus;
 639         int result;
 640
 641         if (policy->cpu != 0)
 642                 return -ENODEV;
 643
 644         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 645
 646         recalibrate_cpu_khz();
 647
 648         fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.CFID];
 649         if (!fsb) {
 650                 printk(KERN_WARNING PFX "can not determine bus frequency\n");
 651                 return -EINVAL;
 652         }
 653         dprintk("FSB: %3dMHz\n", fsb/1000);
 654
 655         if (dmi_check_system(powernow_dmi_table) || acpi_force) {
 656                 printk(KERN_INFO PFX "PSB/PST known to be broken.  "
 657                                 "Trying ACPI instead\n");
 658                 result = powernow_acpi_init();
 659         } else {
 660                 result = powernow_decode_bios(fidvidstatus.bits.MFID,
 661                                 fidvidstatus.bits.SVID);
 662                 if (result) {
 663                         printk(KERN_INFO PFX "Trying ACPI perflib\n");
 664                         maximum_speed = 0;
 665                         minimum_speed = -1;
 666                         latency = 0;
 667                         result = powernow_acpi_init();
 668                         if (result) {
 669                                 printk(KERN_INFO PFX
 670                                         "ACPI and legacy methods failed\n");
 671                         }
 672                 } else {
 673                         /* SGTC use the bus clock as timer */
 674                         latency = fixup_sgtc();
 675                         printk(KERN_INFO PFX "SGTC: %d\n", latency);
 676                 }
 677         }
 678
 679         if (result)
 680                 return result;
 681
 682         printk(KERN_INFO PFX "Minimum speed %d MHz. Maximum speed %d MHz.\n",
 683                                 minimum_speed/1000, maximum_speed/1000);
 684
 685         policy->cpuinfo.transition_latency =
 686                 cpufreq_scale(2000000UL, fsb, latency);
 687
 688         policy->cur = powernow_get(0);
 689
 690         cpufreq_frequency_table_get_attr(powernow_table, policy->cpu);
 691
 692         return cpufreq_frequency_table_cpuinfo(policy, powernow_table);
 693 }
 694
 695 static int powernow_cpu_exit(struct cpufreq_policy *policy)
 696 {
 697         cpufreq_frequency_table_put_attr(policy->cpu);
 698
 699 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 700         if (acpi_processor_perf) {
 701                 acpi_processor_unregister_performance(acpi_processor_perf, 0);
 702                 free_cpumask_var(acpi_processor_perf->shared_cpu_map);
 703                 kfree(acpi_processor_perf);
 704         }
 705 #endif
 706
 707         kfree(powernow_table);
 708         return 0;
 709 }
 710
 711 static struct freq_attr *powernow_table_attr[] = {
 712         &cpufreq_freq_attr_scaling_available_freqs,
 713         NULL,
 714 };
 715
 716 static struct cpufreq_driver powernow_driver = {
 717         .verify = powernow_verify,
 718         .target = powernow_target,
 719         .get    = powernow_get,
 720         .init   = powernow_cpu_init,
 721         .exit   = powernow_cpu_exit,
 722         .name   = "powernow-k7",
 723         .owner  = THIS_MODULE,
 724         .attr   = powernow_table_attr,
 725 };
 726
 727 static int __init powernow_init(void)
 728 {
 729         if (check_powernow() == 0)
 730                 return -ENODEV;
 731         return cpufreq_register_driver(&powernow_driver);
 732 }
 733
 734
 735 static void __exit powernow_exit(void)
 736 {
 737         cpufreq_unregister_driver(&powernow_driver);
 738 }
 739
 740 module_param(acpi_force,  int, 0444);
 741 MODULE_PARM_DESC(acpi_force, "Force ACPI to be used.");
 742
 743 MODULE_AUTHOR("Dave Jones <davej@redhat.com>");
 744 MODULE_DESCRIPTION("Powernow driver for AMD K7 processors.");
 745 MODULE_LICENSE("GPL");
 746
 747 late_initcall(powernow_init);
 748 module_exit(powernow_exit);
 749