oom: fix integer overflow of points in oom_badness
[linux-2.6.git] / drivers / 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 /* 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