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); 748 749