linux/drivers/cpufreq/powernow-k7.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  AMD K7 Powernow driver.
   4 *  (C) 2003 Dave Jones on behalf of SuSE Labs.
   5 *
   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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  17
  18#include <linux/kernel.h>
  19#include <linux/module.h>
  20#include <linux/moduleparam.h>
  21#include <linux/init.h>
  22#include <linux/cpufreq.h>
  23#include <linux/slab.h>
  24#include <linux/string.h>
  25#include <linux/dmi.h>
  26#include <linux/timex.h>
  27#include <linux/io.h>
  28
  29#include <asm/timer.h>          /* Needed for recalibrate_cpu_khz() */
  30#include <asm/msr.h>
  31#include <asm/cpu_device_id.h>
  32
  33#ifdef CONFIG_X86_POWERNOW_K7_ACPI
  34#include <linux/acpi.h>
  35#include <acpi/processor.h>
  36#endif
  37
  38#include "powernow-k7.h"
  39
  40struct psb_s {
  41        u8 signature[10];
  42        u8 tableversion;
  43        u8 flags;
  44        u16 settlingtime;
  45        u8 reserved1;
  46        u8 numpst;
  47};
  48
  49struct 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
  58union 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/* divide by 1000 to get VCore voltage in V. */
  70static const int mobile_vid_table[32] = {
  71    2000, 1950, 1900, 1850, 1800, 1750, 1700, 1650,
  72    1600, 1550, 1500, 1450, 1400, 1350, 1300, 0,
  73    1275, 1250, 1225, 1200, 1175, 1150, 1125, 1100,
  74    1075, 1050, 1025, 1000, 975, 950, 925, 0,
  75};
  76
  77/* divide by 10 to get FID. */
  78static const int fid_codes[32] = {
  79    110, 115, 120, 125, 50, 55, 60, 65,
  80    70, 75, 80, 85, 90, 95, 100, 105,
  81    30, 190, 40, 200, 130, 135, 140, 210,
  82    150, 225, 160, 165, 170, 180, -1, -1,
  83};
  84
  85/* This parameter is used in order to force ACPI instead of legacy method for
  86 * configuration purpose.
  87 */
  88
  89static int acpi_force;
  90
  91static struct cpufreq_frequency_table *powernow_table;
  92
  93static unsigned int can_scale_bus;
  94static unsigned int can_scale_vid;
  95static unsigned int minimum_speed = -1;
  96static unsigned int maximum_speed;
  97static unsigned int number_scales;
  98static unsigned int fsb;
  99static unsigned int latency;
 100static char have_a0;
 101
 102static int check_fsb(unsigned int fsbspeed)
 103{
 104        int delta;
 105        unsigned int f = fsb / 1000;
 106
 107        delta = (fsbspeed > f) ? fsbspeed - f : f - fsbspeed;
 108        return delta < 5;
 109}
 110
 111static const struct x86_cpu_id powernow_k7_cpuids[] = {
 112        X86_MATCH_VENDOR_FAM(AMD, 6, NULL),
 113        {}
 114};
 115MODULE_DEVICE_TABLE(x86cpu, powernow_k7_cpuids);
 116
 117static int check_powernow(void)
 118{
 119        struct cpuinfo_x86 *c = &cpu_data(0);
 120        unsigned int maxei, eax, ebx, ecx, edx;
 121
 122        if (!x86_match_cpu(powernow_k7_cpuids))
 123                return 0;
 124
 125        /* Get maximum capabilities */
 126        maxei = cpuid_eax(0x80000000);
 127        if (maxei < 0x80000007) {       /* Any powernow info ? */
 128#ifdef MODULE
 129                pr_info("No powernow capabilities detected\n");
 130#endif
 131                return 0;
 132        }
 133
 134        if ((c->x86_model == 6) && (c->x86_stepping == 0)) {
 135                pr_info("K7 660[A0] core detected, enabling errata workarounds\n");
 136                have_a0 = 1;
 137        }
 138
 139        cpuid(0x80000007, &eax, &ebx, &ecx, &edx);
 140
 141        /* Check we can actually do something before we say anything.*/
 142        if (!(edx & (1 << 1 | 1 << 2)))
 143                return 0;
 144
 145        pr_info("PowerNOW! Technology present. Can scale: ");
 146
 147        if (edx & 1 << 1) {
 148                pr_cont("frequency");
 149                can_scale_bus = 1;
 150        }
 151
 152        if ((edx & (1 << 1 | 1 << 2)) == 0x6)
 153                pr_cont(" and ");
 154
 155        if (edx & 1 << 2) {
 156                pr_cont("voltage");
 157                can_scale_vid = 1;
 158        }
 159
 160        pr_cont("\n");
 161        return 1;
 162}
 163
 164#ifdef CONFIG_X86_POWERNOW_K7_ACPI
 165static void invalidate_entry(unsigned int entry)
 166{
 167        powernow_table[entry].frequency = CPUFREQ_ENTRY_INVALID;
 168}
 169#endif
 170
 171static int get_ranges(unsigned char *pst)
 172{
 173        unsigned int j;
 174        unsigned int speed;
 175        u8 fid, vid;
 176
 177        powernow_table = kzalloc((sizeof(*powernow_table) *
 178                                (number_scales + 1)), GFP_KERNEL);
 179        if (!powernow_table)
 180                return -ENOMEM;
 181
 182        for (j = 0 ; j < number_scales; j++) {
 183                fid = *pst++;
 184
 185                powernow_table[j].frequency = (fsb * fid_codes[fid]) / 10;
 186                powernow_table[j].driver_data = fid; /* lower 8 bits */
 187
 188                speed = powernow_table[j].frequency;
 189
 190                if ((fid_codes[fid] % 10) == 5) {
 191#ifdef CONFIG_X86_POWERNOW_K7_ACPI
 192                        if (have_a0 == 1)
 193                                invalidate_entry(j);
 194#endif
 195                }
 196
 197                if (speed < minimum_speed)
 198                        minimum_speed = speed;
 199                if (speed > maximum_speed)
 200                        maximum_speed = speed;
 201
 202                vid = *pst++;
 203                powernow_table[j].driver_data |= (vid << 8); /* upper 8 bits */
 204
 205                pr_debug("   FID: 0x%x (%d.%dx [%dMHz])  "
 206                         "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
 207                         fid_codes[fid] % 10, speed/1000, vid,
 208                         mobile_vid_table[vid]/1000,
 209                         mobile_vid_table[vid]%1000);
 210        }
 211        powernow_table[number_scales].frequency = CPUFREQ_TABLE_END;
 212        powernow_table[number_scales].driver_data = 0;
 213
 214        return 0;
 215}
 216
 217
 218static void change_FID(int fid)
 219{
 220        union msr_fidvidctl fidvidctl;
 221
 222        rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 223        if (fidvidctl.bits.FID != fid) {
 224                fidvidctl.bits.SGTC = latency;
 225                fidvidctl.bits.FID = fid;
 226                fidvidctl.bits.VIDC = 0;
 227                fidvidctl.bits.FIDC = 1;
 228                wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 229        }
 230}
 231
 232
 233static void change_VID(int vid)
 234{
 235        union msr_fidvidctl fidvidctl;
 236
 237        rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 238        if (fidvidctl.bits.VID != vid) {
 239                fidvidctl.bits.SGTC = latency;
 240                fidvidctl.bits.VID = vid;
 241                fidvidctl.bits.FIDC = 0;
 242                fidvidctl.bits.VIDC = 1;
 243                wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
 244        }
 245}
 246
 247
 248static int powernow_target(struct cpufreq_policy *policy, unsigned int index)
 249{
 250        u8 fid, vid;
 251        struct cpufreq_freqs freqs;
 252        union msr_fidvidstatus fidvidstatus;
 253        int cfid;
 254
 255        /* fid are the lower 8 bits of the index we stored into
 256         * the cpufreq frequency table in powernow_decode_bios,
 257         * vid are the upper 8 bits.
 258         */
 259
 260        fid = powernow_table[index].driver_data & 0xFF;
 261        vid = (powernow_table[index].driver_data & 0xFF00) >> 8;
 262
 263        rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 264        cfid = fidvidstatus.bits.CFID;
 265        freqs.old = fsb * fid_codes[cfid] / 10;
 266
 267        freqs.new = powernow_table[index].frequency;
 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        return 0;
 289}
 290
 291
 292#ifdef CONFIG_X86_POWERNOW_K7_ACPI
 293
 294static struct acpi_processor_performance *acpi_processor_perf;
 295
 296static 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 = kzalloc(sizeof(*acpi_processor_perf), GFP_KERNEL);
 308        if (!acpi_processor_perf) {
 309                retval = -ENOMEM;
 310                goto err0;
 311        }
 312
 313        if (!zalloc_cpumask_var(&acpi_processor_perf->shared_cpu_map,
 314                                                                GFP_KERNEL)) {
 315                retval = -ENOMEM;
 316                goto err05;
 317        }
 318
 319        if (acpi_processor_register_performance(acpi_processor_perf, 0)) {
 320                retval = -EIO;
 321                goto err1;
 322        }
 323
 324        if (acpi_processor_perf->control_register.space_id !=
 325                        ACPI_ADR_SPACE_FIXED_HARDWARE) {
 326                retval = -ENODEV;
 327                goto err2;
 328        }
 329
 330        if (acpi_processor_perf->status_register.space_id !=
 331                        ACPI_ADR_SPACE_FIXED_HARDWARE) {
 332                retval = -ENODEV;
 333                goto err2;
 334        }
 335
 336        number_scales = acpi_processor_perf->state_count;
 337
 338        if (number_scales < 2) {
 339                retval = -ENODEV;
 340                goto err2;
 341        }
 342
 343        powernow_table = kzalloc((sizeof(*powernow_table) *
 344                                (number_scales + 1)), GFP_KERNEL);
 345        if (!powernow_table) {
 346                retval = -ENOMEM;
 347                goto err2;
 348        }
 349
 350        pc.val = (unsigned long) acpi_processor_perf->states[0].control;
 351        for (i = 0; i < number_scales; i++) {
 352                u8 fid, vid;
 353                struct acpi_processor_px *state =
 354                        &acpi_processor_perf->states[i];
 355                unsigned int speed, speed_mhz;
 356
 357                pc.val = (unsigned long) state->control;
 358                pr_debug("acpi:  P%d: %d MHz %d mW %d uS control %08x SGTC %d\n",
 359                         i,
 360                         (u32) state->core_frequency,
 361                         (u32) state->power,
 362                         (u32) state->transition_latency,
 363                         (u32) state->control,
 364                         pc.bits.sgtc);
 365
 366                vid = pc.bits.vid;
 367                fid = pc.bits.fid;
 368
 369                powernow_table[i].frequency = fsb * fid_codes[fid] / 10;
 370                powernow_table[i].driver_data = fid; /* lower 8 bits */
 371                powernow_table[i].driver_data |= (vid << 8); /* upper 8 bits */
 372
 373                speed = powernow_table[i].frequency;
 374                speed_mhz = speed / 1000;
 375
 376                /* processor_perflib will multiply the MHz value by 1000 to
 377                 * get a KHz value (e.g. 1266000). However, powernow-k7 works
 378                 * with true KHz values (e.g. 1266768). To ensure that all
 379                 * powernow frequencies are available, we must ensure that
 380                 * ACPI doesn't restrict them, so we round up the MHz value
 381                 * to ensure that perflib's computed KHz value is greater than
 382                 * or equal to powernow's KHz value.
 383                 */
 384                if (speed % 1000 > 0)
 385                        speed_mhz++;
 386
 387                if ((fid_codes[fid] % 10) == 5) {
 388                        if (have_a0 == 1)
 389                                invalidate_entry(i);
 390                }
 391
 392                pr_debug("   FID: 0x%x (%d.%dx [%dMHz])  "
 393                         "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
 394                         fid_codes[fid] % 10, speed_mhz, vid,
 395                         mobile_vid_table[vid]/1000,
 396                         mobile_vid_table[vid]%1000);
 397
 398                if (state->core_frequency != speed_mhz) {
 399                        state->core_frequency = speed_mhz;
 400                        pr_debug("   Corrected ACPI frequency to %d\n",
 401                                speed_mhz);
 402                }
 403
 404                if (latency < pc.bits.sgtc)
 405                        latency = pc.bits.sgtc;
 406
 407                if (speed < minimum_speed)
 408                        minimum_speed = speed;
 409                if (speed > maximum_speed)
 410                        maximum_speed = speed;
 411        }
 412
 413        powernow_table[i].frequency = CPUFREQ_TABLE_END;
 414        powernow_table[i].driver_data = 0;
 415
 416        /* notify BIOS that we exist */
 417        acpi_processor_notify_smm(THIS_MODULE);
 418
 419        return 0;
 420
 421err2:
 422        acpi_processor_unregister_performance(0);
 423err1:
 424        free_cpumask_var(acpi_processor_perf->shared_cpu_map);
 425err05:
 426        kfree(acpi_processor_perf);
 427err0:
 428        pr_warn("ACPI perflib can not be used on this platform\n");
 429        acpi_processor_perf = NULL;
 430        return retval;
 431}
 432#else
 433static int powernow_acpi_init(void)
 434{
 435        pr_info("no support for ACPI processor found - please recompile your kernel with ACPI processor\n");
 436        return -EINVAL;
 437}
 438#endif
 439
 440static void print_pst_entry(struct pst_s *pst, unsigned int j)
 441{
 442        pr_debug("PST:%d (@%p)\n", j, pst);
 443        pr_debug(" cpuid: 0x%x  fsb: %d  maxFID: 0x%x  startvid: 0x%x\n",
 444                pst->cpuid, pst->fsbspeed, pst->maxfid, pst->startvid);
 445}
 446
 447static int powernow_decode_bios(int maxfid, int startvid)
 448{
 449        struct psb_s *psb;
 450        struct pst_s *pst;
 451        unsigned int i, j;
 452        unsigned char *p;
 453        unsigned int etuple;
 454        unsigned int ret;
 455
 456        etuple = cpuid_eax(0x80000001);
 457
 458        for (i = 0xC0000; i < 0xffff0 ; i += 16) {
 459
 460                p = phys_to_virt(i);
 461
 462                if (memcmp(p, "AMDK7PNOW!",  10) == 0) {
 463                        pr_debug("Found PSB header at %p\n", p);
 464                        psb = (struct psb_s *) p;
 465                        pr_debug("Table version: 0x%x\n", psb->tableversion);
 466                        if (psb->tableversion != 0x12) {
 467                                pr_info("Sorry, only v1.2 tables supported right now\n");
 468                                return -ENODEV;
 469                        }
 470
 471                        pr_debug("Flags: 0x%x\n", psb->flags);
 472                        if ((psb->flags & 1) == 0)
 473                                pr_debug("Mobile voltage regulator\n");
 474                        else
 475                                pr_debug("Desktop voltage regulator\n");
 476
 477                        latency = psb->settlingtime;
 478                        if (latency < 100) {
 479                                pr_info("BIOS set settling time to %d microseconds. Should be at least 100. Correcting.\n",
 480                                        latency);
 481                                latency = 100;
 482                        }
 483                        pr_debug("Settling Time: %d microseconds.\n",
 484                                        psb->settlingtime);
 485                        pr_debug("Has %d PST tables. (Only dumping ones "
 486                                        "relevant to this CPU).\n",
 487                                        psb->numpst);
 488
 489                        p += sizeof(*psb);
 490
 491                        pst = (struct pst_s *) p;
 492
 493                        for (j = 0; j < psb->numpst; j++) {
 494                                pst = (struct pst_s *) p;
 495                                number_scales = pst->numpstates;
 496
 497                                if ((etuple == pst->cpuid) &&
 498                                    check_fsb(pst->fsbspeed) &&
 499                                    (maxfid == pst->maxfid) &&
 500                                    (startvid == pst->startvid)) {
 501                                        print_pst_entry(pst, j);
 502                                        p = (char *)pst + sizeof(*pst);
 503                                        ret = get_ranges(p);
 504                                        return ret;
 505                                } else {
 506                                        unsigned int k;
 507                                        p = (char *)pst + sizeof(*pst);
 508                                        for (k = 0; k < number_scales; k++)
 509                                                p += 2;
 510                                }
 511                        }
 512                        pr_info("No PST tables match this cpuid (0x%x)\n",
 513                                etuple);
 514                        pr_info("This is indicative of a broken BIOS\n");
 515
 516                        return -EINVAL;
 517                }
 518                p++;
 519        }
 520
 521        return -ENODEV;
 522}
 523
 524
 525/*
 526 * We use the fact that the bus frequency is somehow
 527 * a multiple of 100000/3 khz, then we compute sgtc according
 528 * to this multiple.
 529 * That way, we match more how AMD thinks all of that work.
 530 * We will then get the same kind of behaviour already tested under
 531 * the "well-known" other OS.
 532 */
 533static int fixup_sgtc(void)
 534{
 535        unsigned int sgtc;
 536        unsigned int m;
 537
 538        m = fsb / 3333;
 539        if ((m % 10) >= 5)
 540                m += 5;
 541
 542        m /= 10;
 543
 544        sgtc = 100 * m * latency;
 545        sgtc = sgtc / 3;
 546        if (sgtc > 0xfffff) {
 547                pr_warn("SGTC too large %d\n", sgtc);
 548                sgtc = 0xfffff;
 549        }
 550        return sgtc;
 551}
 552
 553static unsigned int powernow_get(unsigned int cpu)
 554{
 555        union msr_fidvidstatus fidvidstatus;
 556        unsigned int cfid;
 557
 558        if (cpu)
 559                return 0;
 560        rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 561        cfid = fidvidstatus.bits.CFID;
 562
 563        return fsb * fid_codes[cfid] / 10;
 564}
 565
 566
 567static int acer_cpufreq_pst(const struct dmi_system_id *d)
 568{
 569        pr_warn("%s laptop with broken PST tables in BIOS detected\n",
 570                d->ident);
 571        pr_warn("You need to downgrade to 3A21 (09/09/2002), or try a newer BIOS than 3A71 (01/20/2003)\n");
 572        pr_warn("cpufreq scaling has been disabled as a result of this\n");
 573        return 0;
 574}
 575
 576/*
 577 * Some Athlon laptops have really fucked PST tables.
 578 * A BIOS update is all that can save them.
 579 * Mention this, and disable cpufreq.
 580 */
 581static const struct dmi_system_id powernow_dmi_table[] = {
 582        {
 583                .callback = acer_cpufreq_pst,
 584                .ident = "Acer Aspire",
 585                .matches = {
 586                        DMI_MATCH(DMI_SYS_VENDOR, "Insyde Software"),
 587                        DMI_MATCH(DMI_BIOS_VERSION, "3A71"),
 588                },
 589        },
 590        { }
 591};
 592
 593static int powernow_cpu_init(struct cpufreq_policy *policy)
 594{
 595        union msr_fidvidstatus fidvidstatus;
 596        int result;
 597
 598        if (policy->cpu != 0)
 599                return -ENODEV;
 600
 601        rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
 602
 603        recalibrate_cpu_khz();
 604
 605        fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.CFID];
 606        if (!fsb) {
 607                pr_warn("can not determine bus frequency\n");
 608                return -EINVAL;
 609        }
 610        pr_debug("FSB: %3dMHz\n", fsb/1000);
 611
 612        if (dmi_check_system(powernow_dmi_table) || acpi_force) {
 613                pr_info("PSB/PST known to be broken - trying ACPI instead\n");
 614                result = powernow_acpi_init();
 615        } else {
 616                result = powernow_decode_bios(fidvidstatus.bits.MFID,
 617                                fidvidstatus.bits.SVID);
 618                if (result) {
 619                        pr_info("Trying ACPI perflib\n");
 620                        maximum_speed = 0;
 621                        minimum_speed = -1;
 622                        latency = 0;
 623                        result = powernow_acpi_init();
 624                        if (result) {
 625                                pr_info("ACPI and legacy methods failed\n");
 626                        }
 627                } else {
 628                        /* SGTC use the bus clock as timer */
 629                        latency = fixup_sgtc();
 630                        pr_info("SGTC: %d\n", latency);
 631                }
 632        }
 633
 634        if (result)
 635                return result;
 636
 637        pr_info("Minimum speed %d MHz - Maximum speed %d MHz\n",
 638                minimum_speed/1000, maximum_speed/1000);
 639
 640        policy->cpuinfo.transition_latency =
 641                cpufreq_scale(2000000UL, fsb, latency);
 642        policy->freq_table = powernow_table;
 643
 644        return 0;
 645}
 646
 647static int powernow_cpu_exit(struct cpufreq_policy *policy)
 648{
 649#ifdef CONFIG_X86_POWERNOW_K7_ACPI
 650        if (acpi_processor_perf) {
 651                acpi_processor_unregister_performance(0);
 652                free_cpumask_var(acpi_processor_perf->shared_cpu_map);
 653                kfree(acpi_processor_perf);
 654        }
 655#endif
 656
 657        kfree(powernow_table);
 658        return 0;
 659}
 660
 661static struct cpufreq_driver powernow_driver = {
 662        .verify         = cpufreq_generic_frequency_table_verify,
 663        .target_index   = powernow_target,
 664        .get            = powernow_get,
 665#ifdef CONFIG_X86_POWERNOW_K7_ACPI
 666        .bios_limit     = acpi_processor_get_bios_limit,
 667#endif
 668        .init           = powernow_cpu_init,
 669        .exit           = powernow_cpu_exit,
 670        .name           = "powernow-k7",
 671        .attr           = cpufreq_generic_attr,
 672};
 673
 674static int __init powernow_init(void)
 675{
 676        if (check_powernow() == 0)
 677                return -ENODEV;
 678        return cpufreq_register_driver(&powernow_driver);
 679}
 680
 681
 682static void __exit powernow_exit(void)
 683{
 684        cpufreq_unregister_driver(&powernow_driver);
 685}
 686
 687module_param(acpi_force,  int, 0444);
 688MODULE_PARM_DESC(acpi_force, "Force ACPI to be used.");
 689
 690MODULE_AUTHOR("Dave Jones");
 691MODULE_DESCRIPTION("Powernow driver for AMD K7 processors.");
 692MODULE_LICENSE("GPL");
 693
 694late_initcall(powernow_init);
 695module_exit(powernow_exit);
 696
 697