arch/i386/kernel/cpu/cpufreq/powernow-k7.c

   1 /*
   2  *  AMD K7 Powernow driver.
   3  *  (C) 2003 Dave Jones <davej@codemonkey.org.uk> 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: Processor 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: Processors with half frequency multipliers may hang upon wakeup from disconnect.
  12  * - We disable half multipliers if ACPI is used on A0 stepping CPUs.
  13  */
  14
  15 #include <linux/config.h>
  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
  25 #include <asm/msr.h>
  26 #include <asm/timex.h>
  27 #include <asm/io.h>
  28 #include <asm/system.h>
  29
  30 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
  31 #include <linux/acpi.h>
  32 #include <acpi/processor.h>
  33 #endif
  34
  35 #include "powernow-k7.h"
  36
  37 #define PFX "powernow: "
  38
  39
  40 struct psb_s {
  41         u8 signature[10];
  42         u8 tableversion;
  43         u8 flags;
  44         u16 settlingtime;
  45         u8 reserved1;
  46         u8 numpst;
  47 };
  48
  49 struct pst_s {
  50         u32 cpuid;
  51         u8 fsbspeed;
  52         u8 maxfid;
  53         u8 startvid;
  54         u8 numpstates;
  55 };
  56
  57 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
  58 union powernow_acpi_control_t {
  59         struct {
  60                 unsigned long fid:5,
  61                 vid:5,
  62                 sgtc:20,
  63                 res1:2;
  64         } bits;
  65         unsigned long val;
  66 };
  67 #endif
  68
  69 #ifdef CONFIG_CPU_FREQ_DEBUG
  70 /* divide by 1000 to get VCore voltage in V. */
  71 static 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 #endif
  78
  79 /* divide by 10 to get FID. */
  80 static 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 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "powernow-k7", msg)
 105
 106 static int check_fsb(unsigned int fsbspeed)
 107 {
 108         int delta;
 109         unsigned int f = fsb / 1000;
 110
 111         delta = (fsbspeed > f) ? fsbspeed - f : f - fsbspeed;
 112         return (delta < 5);
 113 }
 114
 115 static int check_powernow(void)
 116 {
 117         struct cpuinfo_x86 *c = cpu_data;
 118         unsigned int maxei, eax, ebx, ecx, edx;
 119
 120         if ((c->x86_vendor != X86_VENDOR_AMD) || (c->x86 !=6)) {
 121 #ifdef MODULE
 122                 printk (KERN_INFO PFX "This module only works with AMD K7 CPUs\n");
 123 #endif
 124                 return 0;
 125         }
 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, 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
 167 static int get_ranges (unsigned char *pst)
 168 {
 169         unsigned int j;
 170         unsigned int speed;
 171         u8 fid, vid;
 172
 173         powernow_table = kmalloc((sizeof(struct cpufreq_frequency_table) * (number_scales + 1)), GFP_KERNEL);
 174         if (!powernow_table)
 175                 return -ENOMEM;
 176         memset(powernow_table, 0, (sizeof(struct cpufreq_frequency_table) * (number_scales + 1)));
 177
 178         for (j=0 ; j < number_scales; j++) {
 179                 fid = *pst++;
 180
 181                 powernow_table[j].frequency = (fsb * fid_codes[fid]) / 10;
 182                 powernow_table[j].index = fid; /* lower 8 bits */
 183
 184                 speed = powernow_table[j].frequency;
 185
 186                 if ((fid_codes[fid] % 10)==5) {
 187 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 188                         if (have_a0 == 1)
 189                                 powernow_table[j].frequency = CPUFREQ_ENTRY_INVALID;
 190 #endif
 191                 }
 192
 193                 if (speed < minimum_speed)
 194                         minimum_speed = speed;
 195                 if (speed > maximum_speed)
 196                         maximum_speed = speed;
 197
 198                 vid = *pst++;
 199                 powernow_table[j].index |= (vid << 8); /* upper 8 bits */
 200
 201                 dprintk ("   FID: 0x%x (%d.%dx [%dMHz])  "
 202                          "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
 203                          fid_codes[fid] % 10, speed/1000, vid,
 204                          mobile_vid_table[vid]/1000,
 205                          mobile_vid_table[vid]%1000);
 206         }
 207         powernow_table[number_scales].frequency = CPUFREQ_TABLE_END;
 208         powernow_table[number_scales].index = 0;
 209
 210         return 0;
 211 }
 212
 213
 214 static void change_FID(int fid)
 215 {
 216         union msr_fidvidctl fidvidctl;
 217
 218         rdmsrl (MSR_K7_FID_VID_CTL, fidvidctl.val);
 219         if (fidvidctl.bits.FID != fid) {
 220                 fidvidctl.bits.SGTC = latency;
 221                 fidvidctl.bits.FID = fid;
 222                 fidvidctl.bits.VIDC = 0;
 223                 fidvidctl.bits.FIDC = 1;
 224                 wrmsrl (MSR_K7_FID_VID_CTL, fidvidctl.val);
 225         }
 226 }
 227
 228
 229 static void change_VID(int vid)
 230 {
 231         union msr_fidvidctl fidvidctl;
 232
 233         rdmsrl (MSR_K7_FID_VID_CTL, fidvidctl.val);
 234         if (fidvidctl.bits.VID != vid) {
 235                 fidvidctl.bits.SGTC = latency;
 236                 fidvidctl.bits.VID = vid;
 237                 fidvidctl.bits.FIDC = 0;
 238                 fidvidctl.bits.VIDC = 1;
 239                 wrmsrl (MSR_K7_FID_VID_CTL, fidvidctl.val);
 240         }
 241 }
 242
 243
 244 static void change_speed (unsigned int index)
 245 {
 246         u8 fid, vid;
 247         struct cpufreq_freqs freqs;
 248         union msr_fidvidstatus fidvidstatus;
 249         int cfid;
 250
 251         /* fid are the lower 8 bits of the index we stored into
 252          * the cpufreq frequency table in powernow_decode_bios,
 253          * vid are the upper 8 bits.
 254          */
 255
 256         fid = powernow_table[index].index & 0xFF;
 257         vid = (powernow_table[index].index & 0xFF00) >> 8;
 258
 259         freqs.cpu = 0;
 260
 261         rdmsrl (MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 262         cfid = fidvidstatus.bits.CFID;
 263         freqs.old = fsb * fid_codes[cfid] / 10;
 264
 265         freqs.new = powernow_table[index].frequency;
 266
 267         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 268
 269         /* Now do the magic poking into the MSRs.  */
 270
 271         if (have_a0 == 1)       /* A0 errata 5 */
 272                 local_irq_disable();
 273
 274         if (freqs.old > freqs.new) {
 275                 /* Going down, so change FID first */
 276                 change_FID(fid);
 277                 change_VID(vid);
 278         } else {
 279                 /* Going up, so change VID first */
 280                 change_VID(vid);
 281                 change_FID(fid);
 282         }
 283
 284
 285         if (have_a0 == 1)
 286                 local_irq_enable();
 287
 288         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 289 }
 290
 291
 292 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 293
 294 static struct acpi_processor_performance *acpi_processor_perf;
 295
 296 static int powernow_acpi_init(void)
 297 {
 298         int i;
 299         int retval = 0;
 300         union powernow_acpi_control_t pc;
 301
 302         if (acpi_processor_perf != NULL && powernow_table != NULL) {
 303                 retval = -EINVAL;
 304                 goto err0;
 305         }
 306
 307         acpi_processor_perf = kmalloc(sizeof(struct acpi_processor_performance),
 308                                       GFP_KERNEL);
 309
 310         if (!acpi_processor_perf) {
 311                 retval = -ENOMEM;
 312                 goto err0;
 313         }
 314
 315         memset(acpi_processor_perf, 0, sizeof(struct acpi_processor_performance));
 316
 317         if (acpi_processor_register_performance(acpi_processor_perf, 0)) {
 318                 retval = -EIO;
 319                 goto err1;
 320         }
 321
 322         if (acpi_processor_perf->control_register.space_id != ACPI_ADR_SPACE_FIXED_HARDWARE) {
 323                 retval = -ENODEV;
 324                 goto err2;
 325         }
 326
 327         if (acpi_processor_perf->status_register.space_id != ACPI_ADR_SPACE_FIXED_HARDWARE) {
 328                 retval = -ENODEV;
 329                 goto err2;
 330         }
 331
 332         number_scales = acpi_processor_perf->state_count;
 333
 334         if (number_scales < 2) {
 335                 retval = -ENODEV;
 336                 goto err2;
 337         }
 338
 339         powernow_table = kmalloc((number_scales + 1) * (sizeof(struct cpufreq_frequency_table)), GFP_KERNEL);
 340         if (!powernow_table) {
 341                 retval = -ENOMEM;
 342                 goto err2;
 343         }
 344
 345         memset(powernow_table, 0, ((number_scales + 1) * sizeof(struct cpufreq_frequency_table)));
 346
 347         pc.val = (unsigned long) acpi_processor_perf->states[0].control;
 348         for (i = 0; i < number_scales; i++) {
 349                 u8 fid, vid;
 350                 unsigned int speed;
 351
 352                 pc.val = (unsigned long) acpi_processor_perf->states[i].control;
 353                 dprintk ("acpi:  P%d: %d MHz %d mW %d uS control %08x SGTC %d\n",
 354                          i,
 355                          (u32) acpi_processor_perf->states[i].core_frequency,
 356                          (u32) acpi_processor_perf->states[i].power,
 357                          (u32) acpi_processor_perf->states[i].transition_latency,
 358                          (u32) acpi_processor_perf->states[i].control,
 359                          pc.bits.sgtc);
 360
 361                 vid = pc.bits.vid;
 362                 fid = pc.bits.fid;
 363
 364                 powernow_table[i].frequency = fsb * fid_codes[fid] / 10;
 365                 powernow_table[i].index = fid; /* lower 8 bits */
 366                 powernow_table[i].index |= (vid << 8); /* upper 8 bits */
 367
 368                 speed = powernow_table[i].frequency;
 369
 370                 if ((fid_codes[fid] % 10)==5) {
 371                         if (have_a0 == 1)
 372                                 powernow_table[i].frequency = CPUFREQ_ENTRY_INVALID;
 373                 }
 374
 375                 dprintk ("   FID: 0x%x (%d.%dx [%dMHz])  "
 376                          "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
 377                          fid_codes[fid] % 10, speed/1000, vid,
 378                          mobile_vid_table[vid]/1000,
 379                          mobile_vid_table[vid]%1000);
 380
 381                 if (latency < pc.bits.sgtc)
 382                         latency = pc.bits.sgtc;
 383
 384                 if (speed < minimum_speed)
 385                         minimum_speed = speed;
 386                 if (speed > maximum_speed)
 387                         maximum_speed = speed;
 388         }
 389
 390         powernow_table[i].frequency = CPUFREQ_TABLE_END;
 391         powernow_table[i].index = 0;
 392
 393         /* notify BIOS that we exist */
 394         acpi_processor_notify_smm(THIS_MODULE);
 395
 396         return 0;
 397
 398 err2:
 399         acpi_processor_unregister_performance(acpi_processor_perf, 0);
 400 err1:
 401         kfree(acpi_processor_perf);
 402 err0:
 403         printk(KERN_WARNING PFX "ACPI perflib can not be used in this platform\n");
 404         acpi_processor_perf = NULL;
 405         return retval;
 406 }
 407 #else
 408 static int powernow_acpi_init(void)
 409 {
 410         printk(KERN_INFO PFX "no support for ACPI processor found."
 411                "  Please recompile your kernel with ACPI processor\n");
 412         return -EINVAL;
 413 }
 414 #endif
 415
 416 static int powernow_decode_bios (int maxfid, int startvid)
 417 {
 418         struct psb_s *psb;
 419         struct pst_s *pst;
 420         unsigned int i, j;
 421         unsigned char *p;
 422         unsigned int etuple;
 423         unsigned int ret;
 424
 425         etuple = cpuid_eax(0x80000001);
 426
 427         for (i=0xC0000; i < 0xffff0 ; i+=16) {
 428
 429                 p = phys_to_virt(i);
 430
 431                 if (memcmp(p, "AMDK7PNOW!",  10) == 0){
 432                         dprintk ("Found PSB header at %p\n", p);
 433                         psb = (struct psb_s *) p;
 434                         dprintk ("Table version: 0x%x\n", psb->tableversion);
 435                         if (psb->tableversion != 0x12) {
 436                                 printk (KERN_INFO PFX "Sorry, only v1.2 tables supported right now\n");
 437                                 return -ENODEV;
 438                         }
 439
 440                         dprintk ("Flags: 0x%x\n", psb->flags);
 441                         if ((psb->flags & 1)==0) {
 442                                 dprintk ("Mobile voltage regulator\n");
 443                         } else {
 444                                 dprintk ("Desktop voltage regulator\n");
 445                         }
 446
 447                         latency = psb->settlingtime;
 448                         if (latency < 100) {
 449                                 printk (KERN_INFO PFX "BIOS set settling time to %d microseconds."
 450                                                 "Should be at least 100. Correcting.\n", latency);
 451                                 latency = 100;
 452                         }
 453                         dprintk ("Settling Time: %d microseconds.\n", psb->settlingtime);
 454                         dprintk ("Has %d PST tables. (Only dumping ones relevant to this CPU).\n", psb->numpst);
 455
 456                         p += sizeof (struct psb_s);
 457
 458                         pst = (struct pst_s *) p;
 459
 460                         for (i = 0 ; i <psb->numpst; i++) {
 461                                 pst = (struct pst_s *) p;
 462                                 number_scales = pst->numpstates;
 463
 464                                 if ((etuple == pst->cpuid) && check_fsb(pst->fsbspeed) &&
 465                                     (maxfid==pst->maxfid) && (startvid==pst->startvid))
 466                                 {
 467                                         dprintk ("PST:%d (@%p)\n", i, pst);
 468                                         dprintk (" cpuid: 0x%x  fsb: %d  maxFID: 0x%x  startvid: 0x%x\n",
 469                                                  pst->cpuid, pst->fsbspeed, pst->maxfid, pst->startvid);
 470
 471                                         ret = get_ranges ((char *) pst + sizeof (struct pst_s));
 472                                         return ret;
 473
 474                                 } else {
 475                                         p = (char *) pst + sizeof (struct pst_s);
 476                                         for (j=0 ; j < number_scales; j++)
 477                                                 p+=2;
 478                                 }
 479                         }
 480                         printk (KERN_INFO PFX "No PST tables match this cpuid (0x%x)\n", etuple);
 481                         printk (KERN_INFO PFX "This is indicative of a broken BIOS.\n");
 482
 483                         return -EINVAL;
 484                 }
 485                 p++;
 486         }
 487
 488         return -ENODEV;
 489 }
 490
 491
 492 static int powernow_target (struct cpufreq_policy *policy,
 493                             unsigned int target_freq,
 494                             unsigned int relation)
 495 {
 496         unsigned int newstate;
 497
 498         if (cpufreq_frequency_table_target(policy, powernow_table, target_freq, relation, &newstate))
 499                 return -EINVAL;
 500
 501         change_speed(newstate);
 502
 503         return 0;
 504 }
 505
 506
 507 static int powernow_verify (struct cpufreq_policy *policy)
 508 {
 509         return cpufreq_frequency_table_verify(policy, powernow_table);
 510 }
 511
 512 /*
 513  * We use the fact that the bus frequency is somehow
 514  * a multiple of 100000/3 khz, then we compute sgtc according
 515  * to this multiple.
 516  * That way, we match more how AMD thinks all of that work.
 517  * We will then get the same kind of behaviour already tested under
 518  * the "well-known" other OS.
 519  */
 520 static int __init fixup_sgtc(void)
 521 {
 522         unsigned int sgtc;
 523         unsigned int m;
 524
 525         m = fsb / 3333;
 526         if ((m % 10) >= 5)
 527                 m += 5;
 528
 529         m /= 10;
 530
 531         sgtc = 100 * m * latency;
 532         sgtc = sgtc / 3;
 533         if (sgtc > 0xfffff) {
 534                 printk(KERN_WARNING PFX "SGTC too large %d\n", sgtc);
 535                 sgtc = 0xfffff;
 536         }
 537         return sgtc;
 538 }
 539
 540 static unsigned int powernow_get(unsigned int cpu)
 541 {
 542         union msr_fidvidstatus fidvidstatus;
 543         unsigned int cfid;
 544
 545         if (cpu)
 546                 return 0;
 547         rdmsrl (MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 548         cfid = fidvidstatus.bits.CFID;
 549
 550         return (fsb * fid_codes[cfid] / 10);
 551 }
 552
 553
 554 static int __init acer_cpufreq_pst(struct dmi_system_id *d)
 555 {
 556         printk(KERN_WARNING "%s laptop with broken PST tables in BIOS detected.\n", d->ident);
 557         printk(KERN_WARNING "You need to downgrade to 3A21 (09/09/2002), or try a newer BIOS than 3A71 (01/20/2003)\n");
 558         printk(KERN_WARNING "cpufreq scaling has been disabled as a result of this.\n");
 559         return 0;
 560 }
 561
 562 /*
 563  * Some Athlon laptops have really fucked PST tables.
 564  * A BIOS update is all that can save them.
 565  * Mention this, and disable cpufreq.
 566  */
 567 static struct dmi_system_id __initdata powernow_dmi_table[] = {
 568         {
 569                 .callback = acer_cpufreq_pst,
 570                 .ident = "Acer Aspire",
 571                 .matches = {
 572                         DMI_MATCH(DMI_SYS_VENDOR, "Insyde Software"),
 573                         DMI_MATCH(DMI_BIOS_VERSION, "3A71"),
 574                 },
 575         },
 576         { }
 577 };
 578
 579 static int __init powernow_cpu_init (struct cpufreq_policy *policy)
 580 {
 581         union msr_fidvidstatus fidvidstatus;
 582         int result;
 583
 584         if (policy->cpu != 0)
 585                 return -ENODEV;
 586
 587         rdmsrl (MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 588
 589         /* A K7 with powernow technology is set to max frequency by BIOS */
 590         fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.MFID];
 591         if (!fsb) {
 592                 printk(KERN_WARNING PFX "can not determine bus frequency\n");
 593                 return -EINVAL;
 594         }
 595         dprintk("FSB: %3d.%03d MHz\n", fsb/1000, fsb%1000);
 596
 597         if (dmi_check_system(powernow_dmi_table) || acpi_force) {
 598                 printk (KERN_INFO PFX "PSB/PST known to be broken.  Trying ACPI instead\n");
 599                 result = powernow_acpi_init();
 600         } else {
 601                 result = powernow_decode_bios(fidvidstatus.bits.MFID, fidvidstatus.bits.SVID);
 602                 if (result) {
 603                         printk (KERN_INFO PFX "Trying ACPI perflib\n");
 604                         maximum_speed = 0;
 605                         minimum_speed = -1;
 606                         latency = 0;
 607                         result = powernow_acpi_init();
 608                         if (result) {
 609                                 printk (KERN_INFO PFX "ACPI and legacy methods failed\n");
 610                                 printk (KERN_INFO PFX "See http://www.codemonkey.org.uk/projects/cpufreq/powernow-k7.shtml\n");
 611                         }
 612                 } else {
 613                         /* SGTC use the bus clock as timer */
 614                         latency = fixup_sgtc();
 615                         printk(KERN_INFO PFX "SGTC: %d\n", latency);
 616                 }
 617         }
 618
 619         if (result)
 620                 return result;
 621
 622         printk (KERN_INFO PFX "Minimum speed %d MHz. Maximum speed %d MHz.\n",
 623                                 minimum_speed/1000, maximum_speed/1000);
 624
 625         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 626
 627         policy->cpuinfo.transition_latency = cpufreq_scale(2000000UL, fsb, latency);
 628
 629         policy->cur = powernow_get(0);
 630
 631         cpufreq_frequency_table_get_attr(powernow_table, policy->cpu);
 632
 633         return cpufreq_frequency_table_cpuinfo(policy, powernow_table);
 634 }
 635
 636 static int powernow_cpu_exit (struct cpufreq_policy *policy) {
 637         cpufreq_frequency_table_put_attr(policy->cpu);
 638
 639 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
 640         if (acpi_processor_perf) {
 641                 acpi_processor_unregister_performance(acpi_processor_perf, 0);
 642                 kfree(acpi_processor_perf);
 643         }
 644 #endif
 645
 646         if (powernow_table)
 647                 kfree(powernow_table);
 648
 649         return 0;
 650 }
 651
 652 static struct freq_attr* powernow_table_attr[] = {
 653         &cpufreq_freq_attr_scaling_available_freqs,
 654         NULL,
 655 };
 656
 657 static struct cpufreq_driver powernow_driver = {
 658         .verify = powernow_verify,
 659         .target = powernow_target,
 660         .get    = powernow_get,
 661         .init   = powernow_cpu_init,
 662         .exit   = powernow_cpu_exit,
 663         .name   = "powernow-k7",
 664         .owner  = THIS_MODULE,
 665         .attr   = powernow_table_attr,
 666 };
 667
 668 static int __init powernow_init (void)
 669 {
 670         if (check_powernow()==0)
 671                 return -ENODEV;
 672         return cpufreq_register_driver(&powernow_driver);
 673 }
 674
 675
 676 static void __exit powernow_exit (void)
 677 {
 678         cpufreq_unregister_driver(&powernow_driver);
 679 }
 680
 681 module_param(acpi_force,  int, 0444);
 682 MODULE_PARM_DESC(acpi_force, "Force ACPI to be used.");
 683
 684 MODULE_AUTHOR ("Dave Jones <davej@codemonkey.org.uk>");
 685 MODULE_DESCRIPTION ("Powernow driver for AMD K7 processors.");
 686 MODULE_LICENSE ("GPL");
 687
 688 late_initcall(powernow_init);
 689 module_exit(powernow_exit);
 690