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 /* 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 int check_powernow(void) 114 { 115 struct cpuinfo_x86 *c = &cpu_data(0); 116 unsigned int maxei, eax, ebx, ecx, edx; 117 118 if ((c->x86_vendor != X86_VENDOR_AMD) || (c->x86 != 6)) { 119 #ifdef MODULE 120 printk(KERN_INFO PFX "This module only works with " 121 "AMD K7 CPUs\n"); 122 #endif 123 return 0; 124 } 125 126 /* Get maximum capabilities */ 127 maxei = cpuid_eax(0x80000000); 128 if (maxei < 0x80000007) { /* Any powernow info ? */ 129 #ifdef MODULE 130 printk(KERN_INFO PFX "No powernow capabilities detected\n"); 131 #endif 132 return 0; 133 } 134 135 if ((c->x86_model == 6) && (c->x86_mask == 0)) { 136 printk(KERN_INFO PFX "K7 660[A0] core detected, " 137 "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 #ifdef CONFIG_X86_POWERNOW_K7_ACPI 167 static void invalidate_entry(unsigned int entry) 168 { 169 powernow_table[entry].frequency = CPUFREQ_ENTRY_INVALID; 170 } 171 #endif 172 173 static int get_ranges(unsigned char *pst) 174 { 175 unsigned int j; 176 unsigned int speed; 177 u8 fid, vid; 178 179 powernow_table = kzalloc((sizeof(struct cpufreq_frequency_table) * 180 (number_scales + 1)), GFP_KERNEL); 181 if (!powernow_table) 182 return -ENOMEM; 183 184 for (j = 0 ; j < number_scales; j++) { 185 fid = *pst++; 186 187 powernow_table[j].frequency = (fsb * fid_codes[fid]) / 10; 188 powernow_table[j].index = fid; /* lower 8 bits */ 189 190 speed = powernow_table[j].frequency; 191 192 if ((fid_codes[fid] % 10) == 5) { 193 #ifdef CONFIG_X86_POWERNOW_K7_ACPI 194 if (have_a0 == 1) 195 invalidate_entry(j); 196 #endif 197 } 198 199 if (speed < minimum_speed) 200 minimum_speed = speed; 201 if (speed > maximum_speed) 202 maximum_speed = speed; 203 204 vid = *pst++; 205 powernow_table[j].index |= (vid << 8); /* upper 8 bits */ 206 207 pr_debug(" FID: 0x%x (%d.%dx [%dMHz]) " 208 "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10, 209 fid_codes[fid] % 10, speed/1000, vid, 210 mobile_vid_table[vid]/1000, 211 mobile_vid_table[vid]%1000); 212 } 213 powernow_table[number_scales].frequency = CPUFREQ_TABLE_END; 214 powernow_table[number_scales].index = 0; 215 216 return 0; 217 } 218 219 220 static void change_FID(int fid) 221 { 222 union msr_fidvidctl fidvidctl; 223 224 rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val); 225 if (fidvidctl.bits.FID != fid) { 226 fidvidctl.bits.SGTC = latency; 227 fidvidctl.bits.FID = fid; 228 fidvidctl.bits.VIDC = 0; 229 fidvidctl.bits.FIDC = 1; 230 wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val); 231 } 232 } 233 234 235 static void change_VID(int vid) 236 { 237 union msr_fidvidctl fidvidctl; 238 239 rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val); 240 if (fidvidctl.bits.VID != vid) { 241 fidvidctl.bits.SGTC = latency; 242 fidvidctl.bits.VID = vid; 243 fidvidctl.bits.FIDC = 0; 244 fidvidctl.bits.VIDC = 1; 245 wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val); 246 } 247 } 248 249 250 static void change_speed(unsigned int index) 251 { 252 u8 fid, vid; 253 struct cpufreq_freqs freqs; 254 union msr_fidvidstatus fidvidstatus; 255 int cfid; 256 257 /* fid are the lower 8 bits of the index we stored into 258 * the cpufreq frequency table in powernow_decode_bios, 259 * vid are the upper 8 bits. 260 */ 261 262 fid = powernow_table[index].index & 0xFF; 263 vid = (powernow_table[index].index & 0xFF00) >> 8; 264 265 freqs.cpu = 0; 266 267 rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val); 268 cfid = fidvidstatus.bits.CFID; 269 freqs.old = fsb * fid_codes[cfid] / 10; 270 271 freqs.new = powernow_table[index].frequency; 272 273 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); 274 275 /* Now do the magic poking into the MSRs. */ 276 277 if (have_a0 == 1) /* A0 errata 5 */ 278 local_irq_disable(); 279 280 if (freqs.old > freqs.new) { 281 /* Going down, so change FID first */ 282 change_FID(fid); 283 change_VID(vid); 284 } else { 285 /* Going up, so change VID first */ 286 change_VID(vid); 287 change_FID(fid); 288 } 289 290 291 if (have_a0 == 1) 292 local_irq_enable(); 293 294 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); 295 } 296 297 298 #ifdef CONFIG_X86_POWERNOW_K7_ACPI 299 300 static struct acpi_processor_performance *acpi_processor_perf; 301 302 static int powernow_acpi_init(void) 303 { 304 int i; 305 int retval = 0; 306 union powernow_acpi_control_t pc; 307 308 if (acpi_processor_perf != NULL && powernow_table != NULL) { 309 retval = -EINVAL; 310 goto err0; 311 } 312 313 acpi_processor_perf = kzalloc(sizeof(struct acpi_processor_performance), 314 GFP_KERNEL); 315 if (!acpi_processor_perf) { 316 retval = -ENOMEM; 317 goto err0; 318 } 319 320 if (!zalloc_cpumask_var(&acpi_processor_perf->shared_cpu_map, 321 GFP_KERNEL)) { 322 retval = -ENOMEM; 323 goto err05; 324 } 325 326 if (acpi_processor_register_performance(acpi_processor_perf, 0)) { 327 retval = -EIO; 328 goto err1; 329 } 330 331 if (acpi_processor_perf->control_register.space_id != 332 ACPI_ADR_SPACE_FIXED_HARDWARE) { 333 retval = -ENODEV; 334 goto err2; 335 } 336 337 if (acpi_processor_perf->status_register.space_id != 338 ACPI_ADR_SPACE_FIXED_HARDWARE) { 339 retval = -ENODEV; 340 goto err2; 341 } 342 343 number_scales = acpi_processor_perf->state_count; 344 345 if (number_scales < 2) { 346 retval = -ENODEV; 347 goto err2; 348 } 349 350 powernow_table = kzalloc((sizeof(struct cpufreq_frequency_table) * 351 (number_scales + 1)), GFP_KERNEL); 352 if (!powernow_table) { 353 retval = -ENOMEM; 354 goto err2; 355 } 356 357 pc.val = (unsigned long) acpi_processor_perf->states[0].control; 358 for (i = 0; i < number_scales; i++) { 359 u8 fid, vid; 360 struct acpi_processor_px *state = 361 &acpi_processor_perf->states[i]; 362 unsigned int speed, speed_mhz; 363 364 pc.val = (unsigned long) state->control; 365 pr_debug("acpi: P%d: %d MHz %d mW %d uS control %08x SGTC %d\n", 366 i, 367 (u32) state->core_frequency, 368 (u32) state->power, 369 (u32) state->transition_latency, 370 (u32) state->control, 371 pc.bits.sgtc); 372 373 vid = pc.bits.vid; 374 fid = pc.bits.fid; 375 376 powernow_table[i].frequency = fsb * fid_codes[fid] / 10; 377 powernow_table[i].index = fid; /* lower 8 bits */ 378 powernow_table[i].index |= (vid << 8); /* upper 8 bits */ 379 380 speed = powernow_table[i].frequency; 381 speed_mhz = speed / 1000; 382 383 /* processor_perflib will multiply the MHz value by 1000 to 384 * get a KHz value (e.g. 1266000). However, powernow-k7 works 385 * with true KHz values (e.g. 1266768). To ensure that all 386 * powernow frequencies are available, we must ensure that 387 * ACPI doesn't restrict them, so we round up the MHz value 388 * to ensure that perflib's computed KHz value is greater than 389 * or equal to powernow's KHz value. 390 */ 391 if (speed % 1000 > 0) 392 speed_mhz++; 393 394 if ((fid_codes[fid] % 10) == 5) { 395 if (have_a0 == 1) 396 invalidate_entry(i); 397 } 398 399 pr_debug(" FID: 0x%x (%d.%dx [%dMHz]) " 400 "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10, 401 fid_codes[fid] % 10, speed_mhz, vid, 402 mobile_vid_table[vid]/1000, 403 mobile_vid_table[vid]%1000); 404 405 if (state->core_frequency != speed_mhz) { 406 state->core_frequency = speed_mhz; 407 pr_debug(" Corrected ACPI frequency to %d\n", 408 speed_mhz); 409 } 410 411 if (latency < pc.bits.sgtc) 412 latency = pc.bits.sgtc; 413 414 if (speed < minimum_speed) 415 minimum_speed = speed; 416 if (speed > maximum_speed) 417 maximum_speed = speed; 418 } 419 420 powernow_table[i].frequency = CPUFREQ_TABLE_END; 421 powernow_table[i].index = 0; 422 423 /* notify BIOS that we exist */ 424 acpi_processor_notify_smm(THIS_MODULE); 425 426 return 0; 427 428 err2: 429 acpi_processor_unregister_performance(acpi_processor_perf, 0); 430 err1: 431 free_cpumask_var(acpi_processor_perf->shared_cpu_map); 432 err05: 433 kfree(acpi_processor_perf); 434 err0: 435 printk(KERN_WARNING PFX "ACPI perflib can not be used on " 436 "this platform\n"); 437 acpi_processor_perf = NULL; 438 return retval; 439 } 440 #else 441 static int powernow_acpi_init(void) 442 { 443 printk(KERN_INFO PFX "no support for ACPI processor found." 444 " Please recompile your kernel with ACPI processor\n"); 445 return -EINVAL; 446 } 447 #endif 448 449 static void print_pst_entry(struct pst_s *pst, unsigned int j) 450 { 451 pr_debug("PST:%d (@%p)\n", j, pst); 452 pr_debug(" cpuid: 0x%x fsb: %d maxFID: 0x%x startvid: 0x%x\n", 453 pst->cpuid, pst->fsbspeed, pst->maxfid, pst->startvid); 454 } 455 456 static int powernow_decode_bios(int maxfid, int startvid) 457 { 458 struct psb_s *psb; 459 struct pst_s *pst; 460 unsigned int i, j; 461 unsigned char *p; 462 unsigned int etuple; 463 unsigned int ret; 464 465 etuple = cpuid_eax(0x80000001); 466 467 for (i = 0xC0000; i < 0xffff0 ; i += 16) { 468 469 p = phys_to_virt(i); 470 471 if (memcmp(p, "AMDK7PNOW!", 10) == 0) { 472 pr_debug("Found PSB header at %p\n", p); 473 psb = (struct psb_s *) p; 474 pr_debug("Table version: 0x%x\n", psb->tableversion); 475 if (psb->tableversion != 0x12) { 476 printk(KERN_INFO PFX "Sorry, only v1.2 tables" 477 " supported right now\n"); 478 return -ENODEV; 479 } 480 481 pr_debug("Flags: 0x%x\n", psb->flags); 482 if ((psb->flags & 1) == 0) 483 pr_debug("Mobile voltage regulator\n"); 484 else 485 pr_debug("Desktop voltage regulator\n"); 486 487 latency = psb->settlingtime; 488 if (latency < 100) { 489 printk(KERN_INFO PFX "BIOS set settling time " 490 "to %d microseconds. " 491 "Should be at least 100. " 492 "Correcting.\n", latency); 493 latency = 100; 494 } 495 pr_debug("Settling Time: %d microseconds.\n", 496 psb->settlingtime); 497 pr_debug("Has %d PST tables. (Only dumping ones " 498 "relevant to this CPU).\n", 499 psb->numpst); 500 501 p += sizeof(struct psb_s); 502 503 pst = (struct pst_s *) p; 504 505 for (j = 0; j < psb->numpst; j++) { 506 pst = (struct pst_s *) p; 507 number_scales = pst->numpstates; 508 509 if ((etuple == pst->cpuid) && 510 check_fsb(pst->fsbspeed) && 511 (maxfid == pst->maxfid) && 512 (startvid == pst->startvid)) { 513 print_pst_entry(pst, j); 514 p = (char *)pst + sizeof(struct pst_s); 515 ret = get_ranges(p); 516 return ret; 517 } else { 518 unsigned int k; 519 p = (char *)pst + sizeof(struct pst_s); 520 for (k = 0; k < number_scales; k++) 521 p += 2; 522 } 523 } 524 printk(KERN_INFO PFX "No PST tables match this cpuid " 525 "(0x%x)\n", etuple); 526 printk(KERN_INFO PFX "This is indicative of a broken " 527 "BIOS.\n"); 528 529 return -EINVAL; 530 } 531 p++; 532 } 533 534 return -ENODEV; 535 } 536 537 538 static int powernow_target(struct cpufreq_policy *policy, 539 unsigned int target_freq, 540 unsigned int relation) 541 { 542 unsigned int newstate; 543 544 if (cpufreq_frequency_table_target(policy, powernow_table, target_freq, 545 relation, &newstate)) 546 return -EINVAL; 547 548 change_speed(newstate); 549 550 return 0; 551 } 552 553 554 static int powernow_verify(struct cpufreq_policy *policy) 555 { 556 return cpufreq_frequency_table_verify(policy, powernow_table); 557 } 558 559 /* 560 * We use the fact that the bus frequency is somehow 561 * a multiple of 100000/3 khz, then we compute sgtc according 562 * to this multiple. 563 * That way, we match more how AMD thinks all of that work. 564 * We will then get the same kind of behaviour already tested under 565 * the "well-known" other OS. 566 */ 567 static int __cpuinit fixup_sgtc(void) 568 { 569 unsigned int sgtc; 570 unsigned int m; 571 572 m = fsb / 3333; 573 if ((m % 10) >= 5) 574 m += 5; 575 576 m /= 10; 577 578 sgtc = 100 * m * latency; 579 sgtc = sgtc / 3; 580 if (sgtc > 0xfffff) { 581 printk(KERN_WARNING PFX "SGTC too large %d\n", sgtc); 582 sgtc = 0xfffff; 583 } 584 return sgtc; 585 } 586 587 static unsigned int powernow_get(unsigned int cpu) 588 { 589 union msr_fidvidstatus fidvidstatus; 590 unsigned int cfid; 591 592 if (cpu) 593 return 0; 594 rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val); 595 cfid = fidvidstatus.bits.CFID; 596 597 return fsb * fid_codes[cfid] / 10; 598 } 599 600 601 static int __cpuinit acer_cpufreq_pst(const struct dmi_system_id *d) 602 { 603 printk(KERN_WARNING PFX 604 "%s laptop with broken PST tables in BIOS detected.\n", 605 d->ident); 606 printk(KERN_WARNING PFX 607 "You need to downgrade to 3A21 (09/09/2002), or try a newer " 608 "BIOS than 3A71 (01/20/2003)\n"); 609 printk(KERN_WARNING PFX 610 "cpufreq scaling has been disabled as a result of this.\n"); 611 return 0; 612 } 613 614 /* 615 * Some Athlon laptops have really fucked PST tables. 616 * A BIOS update is all that can save them. 617 * Mention this, and disable cpufreq. 618 */ 619 static struct dmi_system_id __cpuinitdata powernow_dmi_table[] = { 620 { 621 .callback = acer_cpufreq_pst, 622 .ident = "Acer Aspire", 623 .matches = { 624 DMI_MATCH(DMI_SYS_VENDOR, "Insyde Software"), 625 DMI_MATCH(DMI_BIOS_VERSION, "3A71"), 626 }, 627 }, 628 { } 629 }; 630 631 static int __cpuinit powernow_cpu_init(struct cpufreq_policy *policy) 632 { 633 union msr_fidvidstatus fidvidstatus; 634 int result; 635 636 if (policy->cpu != 0) 637 return -ENODEV; 638 639 rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val); 640 641 recalibrate_cpu_khz(); 642 643 fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.CFID]; 644 if (!fsb) { 645 printk(KERN_WARNING PFX "can not determine bus frequency\n"); 646 return -EINVAL; 647 } 648 pr_debug("FSB: %3dMHz\n", fsb/1000); 649 650 if (dmi_check_system(powernow_dmi_table) || acpi_force) { 651 printk(KERN_INFO PFX "PSB/PST known to be broken. " 652 "Trying ACPI instead\n"); 653 result = powernow_acpi_init(); 654 } else { 655 result = powernow_decode_bios(fidvidstatus.bits.MFID, 656 fidvidstatus.bits.SVID); 657 if (result) { 658 printk(KERN_INFO PFX "Trying ACPI perflib\n"); 659 maximum_speed = 0; 660 minimum_speed = -1; 661 latency = 0; 662 result = powernow_acpi_init(); 663 if (result) { 664 printk(KERN_INFO PFX 665 "ACPI and legacy methods failed\n"); 666 } 667 } else { 668 /* SGTC use the bus clock as timer */ 669 latency = fixup_sgtc(); 670 printk(KERN_INFO PFX "SGTC: %d\n", latency); 671 } 672 } 673 674 if (result) 675 return result; 676 677 printk(KERN_INFO PFX "Minimum speed %d MHz. Maximum speed %d MHz.\n", 678 minimum_speed/1000, maximum_speed/1000); 679 680 policy->cpuinfo.transition_latency = 681 cpufreq_scale(2000000UL, fsb, latency); 682 683 policy->cur = powernow_get(0); 684 685 cpufreq_frequency_table_get_attr(powernow_table, policy->cpu); 686 687 return cpufreq_frequency_table_cpuinfo(policy, powernow_table); 688 } 689 690 static int powernow_cpu_exit(struct cpufreq_policy *policy) 691 { 692 cpufreq_frequency_table_put_attr(policy->cpu); 693 694 #ifdef CONFIG_X86_POWERNOW_K7_ACPI 695 if (acpi_processor_perf) { 696 acpi_processor_unregister_performance(acpi_processor_perf, 0); 697 free_cpumask_var(acpi_processor_perf->shared_cpu_map); 698 kfree(acpi_processor_perf); 699 } 700 #endif 701 702 kfree(powernow_table); 703 return 0; 704 } 705 706 static struct freq_attr *powernow_table_attr[] = { 707 &cpufreq_freq_attr_scaling_available_freqs, 708 NULL, 709 }; 710 711 static struct cpufreq_driver powernow_driver = { 712 .verify = powernow_verify, 713 .target = powernow_target, 714 .get = powernow_get, 715 #ifdef CONFIG_X86_POWERNOW_K7_ACPI 716 .bios_limit = acpi_processor_get_bios_limit, 717 #endif 718 .init = powernow_cpu_init, 719 .exit = powernow_cpu_exit, 720 .name = "powernow-k7", 721 .owner = THIS_MODULE, 722 .attr = powernow_table_attr, 723 }; 724 725 static int __init powernow_init(void) 726 { 727 if (check_powernow() == 0) 728 return -ENODEV; 729 return cpufreq_register_driver(&powernow_driver); 730 } 731 732 733 static void __exit powernow_exit(void) 734 { 735 cpufreq_unregister_driver(&powernow_driver); 736 } 737 738 module_param(acpi_force, int, 0444); 739 MODULE_PARM_DESC(acpi_force, "Force ACPI to be used."); 740 741 MODULE_AUTHOR("Dave Jones <davej@redhat.com>"); 742 MODULE_DESCRIPTION("Powernow driver for AMD K7 processors."); 743 MODULE_LICENSE("GPL"); 744 745 late_initcall(powernow_init); 746 module_exit(powernow_exit); 747 748