Merge branches 'release', 'APERF', 'ARAT', 'misc', 'kelvin', 'device-lock' and 'bjorn...
[linux-2.6] / 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 static void invalidate_entry(unsigned int entry)
172 {
173         powernow_table[entry].frequency = CPUFREQ_ENTRY_INVALID;
174 }
175
176 static int get_ranges(unsigned char *pst)
177 {
178         unsigned int j;
179         unsigned int speed;
180         u8 fid, vid;
181
182         powernow_table = kzalloc((sizeof(struct cpufreq_frequency_table) *
183                                 (number_scales + 1)), GFP_KERNEL);
184         if (!powernow_table)
185                 return -ENOMEM;
186
187         for (j = 0 ; j < number_scales; j++) {
188                 fid = *pst++;
189
190                 powernow_table[j].frequency = (fsb * fid_codes[fid]) / 10;
191                 powernow_table[j].index = fid; /* lower 8 bits */
192
193                 speed = powernow_table[j].frequency;
194
195                 if ((fid_codes[fid] % 10) == 5) {
196 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
197                         if (have_a0 == 1)
198                                 invalidate_entry(j);
199 #endif
200                 }
201
202                 if (speed < minimum_speed)
203                         minimum_speed = speed;
204                 if (speed > maximum_speed)
205                         maximum_speed = speed;
206
207                 vid = *pst++;
208                 powernow_table[j].index |= (vid << 8); /* upper 8 bits */
209
210                 dprintk("   FID: 0x%x (%d.%dx [%dMHz])  "
211                          "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
212                          fid_codes[fid] % 10, speed/1000, vid,
213                          mobile_vid_table[vid]/1000,
214                          mobile_vid_table[vid]%1000);
215         }
216         powernow_table[number_scales].frequency = CPUFREQ_TABLE_END;
217         powernow_table[number_scales].index = 0;
218
219         return 0;
220 }
221
222
223 static void change_FID(int fid)
224 {
225         union msr_fidvidctl fidvidctl;
226
227         rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
228         if (fidvidctl.bits.FID != fid) {
229                 fidvidctl.bits.SGTC = latency;
230                 fidvidctl.bits.FID = fid;
231                 fidvidctl.bits.VIDC = 0;
232                 fidvidctl.bits.FIDC = 1;
233                 wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
234         }
235 }
236
237
238 static void change_VID(int vid)
239 {
240         union msr_fidvidctl fidvidctl;
241
242         rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
243         if (fidvidctl.bits.VID != vid) {
244                 fidvidctl.bits.SGTC = latency;
245                 fidvidctl.bits.VID = vid;
246                 fidvidctl.bits.FIDC = 0;
247                 fidvidctl.bits.VIDC = 1;
248                 wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
249         }
250 }
251
252
253 static void change_speed(unsigned int index)
254 {
255         u8 fid, vid;
256         struct cpufreq_freqs freqs;
257         union msr_fidvidstatus fidvidstatus;
258         int cfid;
259
260         /* fid are the lower 8 bits of the index we stored into
261          * the cpufreq frequency table in powernow_decode_bios,
262          * vid are the upper 8 bits.
263          */
264
265         fid = powernow_table[index].index & 0xFF;
266         vid = (powernow_table[index].index & 0xFF00) >> 8;
267
268         freqs.cpu = 0;
269
270         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
271         cfid = fidvidstatus.bits.CFID;
272         freqs.old = fsb * fid_codes[cfid] / 10;
273
274         freqs.new = powernow_table[index].frequency;
275
276         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
277
278         /* Now do the magic poking into the MSRs.  */
279
280         if (have_a0 == 1)       /* A0 errata 5 */
281                 local_irq_disable();
282
283         if (freqs.old > freqs.new) {
284                 /* Going down, so change FID first */
285                 change_FID(fid);
286                 change_VID(vid);
287         } else {
288                 /* Going up, so change VID first */
289                 change_VID(vid);
290                 change_FID(fid);
291         }
292
293
294         if (have_a0 == 1)
295                 local_irq_enable();
296
297         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
298 }
299
300
301 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
302
303 static struct acpi_processor_performance *acpi_processor_perf;
304
305 static int powernow_acpi_init(void)
306 {
307         int i;
308         int retval = 0;
309         union powernow_acpi_control_t pc;
310
311         if (acpi_processor_perf != NULL && powernow_table != NULL) {
312                 retval = -EINVAL;
313                 goto err0;
314         }
315
316         acpi_processor_perf = kzalloc(sizeof(struct acpi_processor_performance),
317                                       GFP_KERNEL);
318         if (!acpi_processor_perf) {
319                 retval = -ENOMEM;
320                 goto err0;
321         }
322
323         if (!alloc_cpumask_var(&acpi_processor_perf->shared_cpu_map,
324                                                                 GFP_KERNEL)) {
325                 retval = -ENOMEM;
326                 goto err05;
327         }
328
329         if (acpi_processor_register_performance(acpi_processor_perf, 0)) {
330                 retval = -EIO;
331                 goto err1;
332         }
333
334         if (acpi_processor_perf->control_register.space_id !=
335                         ACPI_ADR_SPACE_FIXED_HARDWARE) {
336                 retval = -ENODEV;
337                 goto err2;
338         }
339
340         if (acpi_processor_perf->status_register.space_id !=
341                         ACPI_ADR_SPACE_FIXED_HARDWARE) {
342                 retval = -ENODEV;
343                 goto err2;
344         }
345
346         number_scales = acpi_processor_perf->state_count;
347
348         if (number_scales < 2) {
349                 retval = -ENODEV;
350                 goto err2;
351         }
352
353         powernow_table = kzalloc((sizeof(struct cpufreq_frequency_table) *
354                                 (number_scales + 1)), GFP_KERNEL);
355         if (!powernow_table) {
356                 retval = -ENOMEM;
357                 goto err2;
358         }
359
360         pc.val = (unsigned long) acpi_processor_perf->states[0].control;
361         for (i = 0; i < number_scales; i++) {
362                 u8 fid, vid;
363                 struct acpi_processor_px *state =
364                         &acpi_processor_perf->states[i];
365                 unsigned int speed, speed_mhz;
366
367                 pc.val = (unsigned long) state->control;
368                 dprintk("acpi:  P%d: %d MHz %d mW %d uS control %08x SGTC %d\n",
369                          i,
370                          (u32) state->core_frequency,
371                          (u32) state->power,
372                          (u32) state->transition_latency,
373                          (u32) state->control,
374                          pc.bits.sgtc);
375
376                 vid = pc.bits.vid;
377                 fid = pc.bits.fid;
378
379                 powernow_table[i].frequency = fsb * fid_codes[fid] / 10;
380                 powernow_table[i].index = fid; /* lower 8 bits */
381                 powernow_table[i].index |= (vid << 8); /* upper 8 bits */
382
383                 speed = powernow_table[i].frequency;
384                 speed_mhz = speed / 1000;
385
386                 /* processor_perflib will multiply the MHz value by 1000 to
387                  * get a KHz value (e.g. 1266000). However, powernow-k7 works
388                  * with true KHz values (e.g. 1266768). To ensure that all
389                  * powernow frequencies are available, we must ensure that
390                  * ACPI doesn't restrict them, so we round up the MHz value
391                  * to ensure that perflib's computed KHz value is greater than
392                  * or equal to powernow's KHz value.
393                  */
394                 if (speed % 1000 > 0)
395                         speed_mhz++;
396
397                 if ((fid_codes[fid] % 10) == 5) {
398                         if (have_a0 == 1)
399                                 invalidate_entry(i);
400                 }
401
402                 dprintk("   FID: 0x%x (%d.%dx [%dMHz])  "
403                          "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
404                          fid_codes[fid] % 10, speed_mhz, vid,
405                          mobile_vid_table[vid]/1000,
406                          mobile_vid_table[vid]%1000);
407
408                 if (state->core_frequency != speed_mhz) {
409                         state->core_frequency = speed_mhz;
410                         dprintk("   Corrected ACPI frequency to %d\n",
411                                 speed_mhz);
412                 }
413
414                 if (latency < pc.bits.sgtc)
415                         latency = pc.bits.sgtc;
416
417                 if (speed < minimum_speed)
418                         minimum_speed = speed;
419                 if (speed > maximum_speed)
420                         maximum_speed = speed;
421         }
422
423         powernow_table[i].frequency = CPUFREQ_TABLE_END;
424         powernow_table[i].index = 0;
425
426         /* notify BIOS that we exist */
427         acpi_processor_notify_smm(THIS_MODULE);
428
429         return 0;
430
431 err2:
432         acpi_processor_unregister_performance(acpi_processor_perf, 0);
433 err1:
434         free_cpumask_var(acpi_processor_perf->shared_cpu_map);
435 err05:
436         kfree(acpi_processor_perf);
437 err0:
438         printk(KERN_WARNING PFX "ACPI perflib can not be used on "
439                         "this platform\n");
440         acpi_processor_perf = NULL;
441         return retval;
442 }
443 #else
444 static int powernow_acpi_init(void)
445 {
446         printk(KERN_INFO PFX "no support for ACPI processor found."
447                "  Please recompile your kernel with ACPI processor\n");
448         return -EINVAL;
449 }
450 #endif
451
452 static void print_pst_entry(struct pst_s *pst, unsigned int j)
453 {
454         dprintk("PST:%d (@%p)\n", j, pst);
455         dprintk(" cpuid: 0x%x  fsb: %d  maxFID: 0x%x  startvid: 0x%x\n",
456                 pst->cpuid, pst->fsbspeed, pst->maxfid, pst->startvid);
457 }
458
459 static int powernow_decode_bios(int maxfid, int startvid)
460 {
461         struct psb_s *psb;
462         struct pst_s *pst;
463         unsigned int i, j;
464         unsigned char *p;
465         unsigned int etuple;
466         unsigned int ret;
467
468         etuple = cpuid_eax(0x80000001);
469
470         for (i = 0xC0000; i < 0xffff0 ; i += 16) {
471
472                 p = phys_to_virt(i);
473
474                 if (memcmp(p, "AMDK7PNOW!",  10) == 0) {
475                         dprintk("Found PSB header at %p\n", p);
476                         psb = (struct psb_s *) p;
477                         dprintk("Table version: 0x%x\n", psb->tableversion);
478                         if (psb->tableversion != 0x12) {
479                                 printk(KERN_INFO PFX "Sorry, only v1.2 tables"
480                                                 " supported right now\n");
481                                 return -ENODEV;
482                         }
483
484                         dprintk("Flags: 0x%x\n", psb->flags);
485                         if ((psb->flags & 1) == 0)
486                                 dprintk("Mobile voltage regulator\n");
487                         else
488                                 dprintk("Desktop voltage regulator\n");
489
490                         latency = psb->settlingtime;
491                         if (latency < 100) {
492                                 printk(KERN_INFO PFX "BIOS set settling time "
493                                                 "to %d microseconds. "
494                                                 "Should be at least 100. "
495                                                 "Correcting.\n", latency);
496                                 latency = 100;
497                         }
498                         dprintk("Settling Time: %d microseconds.\n",
499                                         psb->settlingtime);
500                         dprintk("Has %d PST tables. (Only dumping ones "
501                                         "relevant to this CPU).\n",
502                                         psb->numpst);
503
504                         p += sizeof(struct psb_s);
505
506                         pst = (struct pst_s *) p;
507
508                         for (j = 0; j < psb->numpst; j++) {
509                                 pst = (struct pst_s *) p;
510                                 number_scales = pst->numpstates;
511
512                                 if ((etuple == pst->cpuid) &&
513                                     check_fsb(pst->fsbspeed) &&
514                                     (maxfid == pst->maxfid) &&
515                                     (startvid == pst->startvid)) {
516                                         print_pst_entry(pst, j);
517                                         p = (char *)pst + sizeof(struct pst_s);
518                                         ret = get_ranges(p);
519                                         return ret;
520                                 } else {
521                                         unsigned int k;
522                                         p = (char *)pst + sizeof(struct pst_s);
523                                         for (k = 0; k < number_scales; k++)
524                                                 p += 2;
525                                 }
526                         }
527                         printk(KERN_INFO PFX "No PST tables match this cpuid "
528                                         "(0x%x)\n", etuple);
529                         printk(KERN_INFO PFX "This is indicative of a broken "
530                                         "BIOS.\n");
531
532                         return -EINVAL;
533                 }
534                 p++;
535         }
536
537         return -ENODEV;
538 }
539
540
541 static int powernow_target(struct cpufreq_policy *policy,
542                             unsigned int target_freq,
543                             unsigned int relation)
544 {
545         unsigned int newstate;
546
547         if (cpufreq_frequency_table_target(policy, powernow_table, target_freq,
548                                 relation, &newstate))
549                 return -EINVAL;
550
551         change_speed(newstate);
552
553         return 0;
554 }
555
556
557 static int powernow_verify(struct cpufreq_policy *policy)
558 {
559         return cpufreq_frequency_table_verify(policy, powernow_table);
560 }
561
562 /*
563  * We use the fact that the bus frequency is somehow
564  * a multiple of 100000/3 khz, then we compute sgtc according
565  * to this multiple.
566  * That way, we match more how AMD thinks all of that work.
567  * We will then get the same kind of behaviour already tested under
568  * the "well-known" other OS.
569  */
570 static int __init fixup_sgtc(void)
571 {
572         unsigned int sgtc;
573         unsigned int m;
574
575         m = fsb / 3333;
576         if ((m % 10) >= 5)
577                 m += 5;
578
579         m /= 10;
580
581         sgtc = 100 * m * latency;
582         sgtc = sgtc / 3;
583         if (sgtc > 0xfffff) {
584                 printk(KERN_WARNING PFX "SGTC too large %d\n", sgtc);
585                 sgtc = 0xfffff;
586         }
587         return sgtc;
588 }
589
590 static unsigned int powernow_get(unsigned int cpu)
591 {
592         union msr_fidvidstatus fidvidstatus;
593         unsigned int cfid;
594
595         if (cpu)
596                 return 0;
597         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
598         cfid = fidvidstatus.bits.CFID;
599
600         return fsb * fid_codes[cfid] / 10;
601 }
602
603
604 static int __init acer_cpufreq_pst(const struct dmi_system_id *d)
605 {
606         printk(KERN_WARNING PFX
607                 "%s laptop with broken PST tables in BIOS detected.\n",
608                 d->ident);
609         printk(KERN_WARNING PFX
610                 "You need to downgrade to 3A21 (09/09/2002), or try a newer "
611                 "BIOS than 3A71 (01/20/2003)\n");
612         printk(KERN_WARNING PFX
613                 "cpufreq scaling has been disabled as a result of this.\n");
614         return 0;
615 }
616
617 /*
618  * Some Athlon laptops have really fucked PST tables.
619  * A BIOS update is all that can save them.
620  * Mention this, and disable cpufreq.
621  */
622 static struct dmi_system_id __initdata powernow_dmi_table[] = {
623         {
624                 .callback = acer_cpufreq_pst,
625                 .ident = "Acer Aspire",
626                 .matches = {
627                         DMI_MATCH(DMI_SYS_VENDOR, "Insyde Software"),
628                         DMI_MATCH(DMI_BIOS_VERSION, "3A71"),
629                 },
630         },
631         { }
632 };
633
634 static int __init powernow_cpu_init(struct cpufreq_policy *policy)
635 {
636         union msr_fidvidstatus fidvidstatus;
637         int result;
638
639         if (policy->cpu != 0)
640                 return -ENODEV;
641
642         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
643
644         recalibrate_cpu_khz();
645
646         fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.CFID];
647         if (!fsb) {
648                 printk(KERN_WARNING PFX "can not determine bus frequency\n");
649                 return -EINVAL;
650         }
651         dprintk("FSB: %3dMHz\n", fsb/1000);
652
653         if (dmi_check_system(powernow_dmi_table) || acpi_force) {
654                 printk(KERN_INFO PFX "PSB/PST known to be broken.  "
655                                 "Trying ACPI instead\n");
656                 result = powernow_acpi_init();
657         } else {
658                 result = powernow_decode_bios(fidvidstatus.bits.MFID,
659                                 fidvidstatus.bits.SVID);
660                 if (result) {
661                         printk(KERN_INFO PFX "Trying ACPI perflib\n");
662                         maximum_speed = 0;
663                         minimum_speed = -1;
664                         latency = 0;
665                         result = powernow_acpi_init();
666                         if (result) {
667                                 printk(KERN_INFO PFX
668                                         "ACPI and legacy methods failed\n");
669                         }
670                 } else {
671                         /* SGTC use the bus clock as timer */
672                         latency = fixup_sgtc();
673                         printk(KERN_INFO PFX "SGTC: %d\n", latency);
674                 }
675         }
676
677         if (result)
678                 return result;
679
680         printk(KERN_INFO PFX "Minimum speed %d MHz. Maximum speed %d MHz.\n",
681                                 minimum_speed/1000, maximum_speed/1000);
682
683         policy->cpuinfo.transition_latency =
684                 cpufreq_scale(2000000UL, fsb, latency);
685
686         policy->cur = powernow_get(0);
687
688         cpufreq_frequency_table_get_attr(powernow_table, policy->cpu);
689
690         return cpufreq_frequency_table_cpuinfo(policy, powernow_table);
691 }
692
693 static int powernow_cpu_exit(struct cpufreq_policy *policy)
694 {
695         cpufreq_frequency_table_put_attr(policy->cpu);
696
697 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
698         if (acpi_processor_perf) {
699                 acpi_processor_unregister_performance(acpi_processor_perf, 0);
700                 free_cpumask_var(acpi_processor_perf->shared_cpu_map);
701                 kfree(acpi_processor_perf);
702         }
703 #endif
704
705         kfree(powernow_table);
706         return 0;
707 }
708
709 static struct freq_attr *powernow_table_attr[] = {
710         &cpufreq_freq_attr_scaling_available_freqs,
711         NULL,
712 };
713
714 static struct cpufreq_driver powernow_driver = {
715         .verify = powernow_verify,
716         .target = powernow_target,
717         .get    = powernow_get,
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