Merge branch 'gart/rename' of git://git.kernel.org/pub/scm/linux/kernel/git/joro...
[linux-2.6.git] / 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 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
172 static void invalidate_entry(unsigned int entry)
173 {
174         powernow_table[entry].frequency = CPUFREQ_ENTRY_INVALID;
175 }
176 #endif
177
178 static int get_ranges(unsigned char *pst)
179 {
180         unsigned int j;
181         unsigned int speed;
182         u8 fid, vid;
183
184         powernow_table = kzalloc((sizeof(struct cpufreq_frequency_table) *
185                                 (number_scales + 1)), GFP_KERNEL);
186         if (!powernow_table)
187                 return -ENOMEM;
188
189         for (j = 0 ; j < number_scales; j++) {
190                 fid = *pst++;
191
192                 powernow_table[j].frequency = (fsb * fid_codes[fid]) / 10;
193                 powernow_table[j].index = fid; /* lower 8 bits */
194
195                 speed = powernow_table[j].frequency;
196
197                 if ((fid_codes[fid] % 10) == 5) {
198 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
199                         if (have_a0 == 1)
200                                 invalidate_entry(j);
201 #endif
202                 }
203
204                 if (speed < minimum_speed)
205                         minimum_speed = speed;
206                 if (speed > maximum_speed)
207                         maximum_speed = speed;
208
209                 vid = *pst++;
210                 powernow_table[j].index |= (vid << 8); /* upper 8 bits */
211
212                 dprintk("   FID: 0x%x (%d.%dx [%dMHz])  "
213                          "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
214                          fid_codes[fid] % 10, speed/1000, vid,
215                          mobile_vid_table[vid]/1000,
216                          mobile_vid_table[vid]%1000);
217         }
218         powernow_table[number_scales].frequency = CPUFREQ_TABLE_END;
219         powernow_table[number_scales].index = 0;
220
221         return 0;
222 }
223
224
225 static void change_FID(int fid)
226 {
227         union msr_fidvidctl fidvidctl;
228
229         rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
230         if (fidvidctl.bits.FID != fid) {
231                 fidvidctl.bits.SGTC = latency;
232                 fidvidctl.bits.FID = fid;
233                 fidvidctl.bits.VIDC = 0;
234                 fidvidctl.bits.FIDC = 1;
235                 wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
236         }
237 }
238
239
240 static void change_VID(int vid)
241 {
242         union msr_fidvidctl fidvidctl;
243
244         rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
245         if (fidvidctl.bits.VID != vid) {
246                 fidvidctl.bits.SGTC = latency;
247                 fidvidctl.bits.VID = vid;
248                 fidvidctl.bits.FIDC = 0;
249                 fidvidctl.bits.VIDC = 1;
250                 wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
251         }
252 }
253
254
255 static void change_speed(unsigned int index)
256 {
257         u8 fid, vid;
258         struct cpufreq_freqs freqs;
259         union msr_fidvidstatus fidvidstatus;
260         int cfid;
261
262         /* fid are the lower 8 bits of the index we stored into
263          * the cpufreq frequency table in powernow_decode_bios,
264          * vid are the upper 8 bits.
265          */
266
267         fid = powernow_table[index].index & 0xFF;
268         vid = (powernow_table[index].index & 0xFF00) >> 8;
269
270         freqs.cpu = 0;
271
272         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
273         cfid = fidvidstatus.bits.CFID;
274         freqs.old = fsb * fid_codes[cfid] / 10;
275
276         freqs.new = powernow_table[index].frequency;
277
278         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
279
280         /* Now do the magic poking into the MSRs.  */
281
282         if (have_a0 == 1)       /* A0 errata 5 */
283                 local_irq_disable();
284
285         if (freqs.old > freqs.new) {
286                 /* Going down, so change FID first */
287                 change_FID(fid);
288                 change_VID(vid);
289         } else {
290                 /* Going up, so change VID first */
291                 change_VID(vid);
292                 change_FID(fid);
293         }
294
295
296         if (have_a0 == 1)
297                 local_irq_enable();
298
299         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
300 }
301
302
303 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
304
305 static struct acpi_processor_performance *acpi_processor_perf;
306
307 static int powernow_acpi_init(void)
308 {
309         int i;
310         int retval = 0;
311         union powernow_acpi_control_t pc;
312
313         if (acpi_processor_perf != NULL && powernow_table != NULL) {
314                 retval = -EINVAL;
315                 goto err0;
316         }
317
318         acpi_processor_perf = kzalloc(sizeof(struct acpi_processor_performance),
319                                       GFP_KERNEL);
320         if (!acpi_processor_perf) {
321                 retval = -ENOMEM;
322                 goto err0;
323         }
324
325         if (!zalloc_cpumask_var(&acpi_processor_perf->shared_cpu_map,
326                                                                 GFP_KERNEL)) {
327                 retval = -ENOMEM;
328                 goto err05;
329         }
330
331         if (acpi_processor_register_performance(acpi_processor_perf, 0)) {
332                 retval = -EIO;
333                 goto err1;
334         }
335
336         if (acpi_processor_perf->control_register.space_id !=
337                         ACPI_ADR_SPACE_FIXED_HARDWARE) {
338                 retval = -ENODEV;
339                 goto err2;
340         }
341
342         if (acpi_processor_perf->status_register.space_id !=
343                         ACPI_ADR_SPACE_FIXED_HARDWARE) {
344                 retval = -ENODEV;
345                 goto err2;
346         }
347
348         number_scales = acpi_processor_perf->state_count;
349
350         if (number_scales < 2) {
351                 retval = -ENODEV;
352                 goto err2;
353         }
354
355         powernow_table = kzalloc((sizeof(struct cpufreq_frequency_table) *
356                                 (number_scales + 1)), GFP_KERNEL);
357         if (!powernow_table) {
358                 retval = -ENOMEM;
359                 goto err2;
360         }
361
362         pc.val = (unsigned long) acpi_processor_perf->states[0].control;
363         for (i = 0; i < number_scales; i++) {
364                 u8 fid, vid;
365                 struct acpi_processor_px *state =
366                         &acpi_processor_perf->states[i];
367                 unsigned int speed, speed_mhz;
368
369                 pc.val = (unsigned long) state->control;
370                 dprintk("acpi:  P%d: %d MHz %d mW %d uS control %08x SGTC %d\n",
371                          i,
372                          (u32) state->core_frequency,
373                          (u32) state->power,
374                          (u32) state->transition_latency,
375                          (u32) state->control,
376                          pc.bits.sgtc);
377
378                 vid = pc.bits.vid;
379                 fid = pc.bits.fid;
380
381                 powernow_table[i].frequency = fsb * fid_codes[fid] / 10;
382                 powernow_table[i].index = fid; /* lower 8 bits */
383                 powernow_table[i].index |= (vid << 8); /* upper 8 bits */
384
385                 speed = powernow_table[i].frequency;
386                 speed_mhz = speed / 1000;
387
388                 /* processor_perflib will multiply the MHz value by 1000 to
389                  * get a KHz value (e.g. 1266000). However, powernow-k7 works
390                  * with true KHz values (e.g. 1266768). To ensure that all
391                  * powernow frequencies are available, we must ensure that
392                  * ACPI doesn't restrict them, so we round up the MHz value
393                  * to ensure that perflib's computed KHz value is greater than
394                  * or equal to powernow's KHz value.
395                  */
396                 if (speed % 1000 > 0)
397                         speed_mhz++;
398
399                 if ((fid_codes[fid] % 10) == 5) {
400                         if (have_a0 == 1)
401                                 invalidate_entry(i);
402                 }
403
404                 dprintk("   FID: 0x%x (%d.%dx [%dMHz])  "
405                          "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
406                          fid_codes[fid] % 10, speed_mhz, vid,
407                          mobile_vid_table[vid]/1000,
408                          mobile_vid_table[vid]%1000);
409
410                 if (state->core_frequency != speed_mhz) {
411                         state->core_frequency = speed_mhz;
412                         dprintk("   Corrected ACPI frequency to %d\n",
413                                 speed_mhz);
414                 }
415
416                 if (latency < pc.bits.sgtc)
417                         latency = pc.bits.sgtc;
418
419                 if (speed < minimum_speed)
420                         minimum_speed = speed;
421                 if (speed > maximum_speed)
422                         maximum_speed = speed;
423         }
424
425         powernow_table[i].frequency = CPUFREQ_TABLE_END;
426         powernow_table[i].index = 0;
427
428         /* notify BIOS that we exist */
429         acpi_processor_notify_smm(THIS_MODULE);
430
431         return 0;
432
433 err2:
434         acpi_processor_unregister_performance(acpi_processor_perf, 0);
435 err1:
436         free_cpumask_var(acpi_processor_perf->shared_cpu_map);
437 err05:
438         kfree(acpi_processor_perf);
439 err0:
440         printk(KERN_WARNING PFX "ACPI perflib can not be used on "
441                         "this platform\n");
442         acpi_processor_perf = NULL;
443         return retval;
444 }
445 #else
446 static int powernow_acpi_init(void)
447 {
448         printk(KERN_INFO PFX "no support for ACPI processor found."
449                "  Please recompile your kernel with ACPI processor\n");
450         return -EINVAL;
451 }
452 #endif
453
454 static void print_pst_entry(struct pst_s *pst, unsigned int j)
455 {
456         dprintk("PST:%d (@%p)\n", j, pst);
457         dprintk(" cpuid: 0x%x  fsb: %d  maxFID: 0x%x  startvid: 0x%x\n",
458                 pst->cpuid, pst->fsbspeed, pst->maxfid, pst->startvid);
459 }
460
461 static int powernow_decode_bios(int maxfid, int startvid)
462 {
463         struct psb_s *psb;
464         struct pst_s *pst;
465         unsigned int i, j;
466         unsigned char *p;
467         unsigned int etuple;
468         unsigned int ret;
469
470         etuple = cpuid_eax(0x80000001);
471
472         for (i = 0xC0000; i < 0xffff0 ; i += 16) {
473
474                 p = phys_to_virt(i);
475
476                 if (memcmp(p, "AMDK7PNOW!",  10) == 0) {
477                         dprintk("Found PSB header at %p\n", p);
478                         psb = (struct psb_s *) p;
479                         dprintk("Table version: 0x%x\n", psb->tableversion);
480                         if (psb->tableversion != 0x12) {
481                                 printk(KERN_INFO PFX "Sorry, only v1.2 tables"
482                                                 " supported right now\n");
483                                 return -ENODEV;
484                         }
485
486                         dprintk("Flags: 0x%x\n", psb->flags);
487                         if ((psb->flags & 1) == 0)
488                                 dprintk("Mobile voltage regulator\n");
489                         else
490                                 dprintk("Desktop voltage regulator\n");
491
492                         latency = psb->settlingtime;
493                         if (latency < 100) {
494                                 printk(KERN_INFO PFX "BIOS set settling time "
495                                                 "to %d microseconds. "
496                                                 "Should be at least 100. "
497                                                 "Correcting.\n", latency);
498                                 latency = 100;
499                         }
500                         dprintk("Settling Time: %d microseconds.\n",
501                                         psb->settlingtime);
502                         dprintk("Has %d PST tables. (Only dumping ones "
503                                         "relevant to this CPU).\n",
504                                         psb->numpst);
505
506                         p += sizeof(struct psb_s);
507
508                         pst = (struct pst_s *) p;
509
510                         for (j = 0; j < psb->numpst; j++) {
511                                 pst = (struct pst_s *) p;
512                                 number_scales = pst->numpstates;
513
514                                 if ((etuple == pst->cpuid) &&
515                                     check_fsb(pst->fsbspeed) &&
516                                     (maxfid == pst->maxfid) &&
517                                     (startvid == pst->startvid)) {
518                                         print_pst_entry(pst, j);
519                                         p = (char *)pst + sizeof(struct pst_s);
520                                         ret = get_ranges(p);
521                                         return ret;
522                                 } else {
523                                         unsigned int k;
524                                         p = (char *)pst + sizeof(struct pst_s);
525                                         for (k = 0; k < number_scales; k++)
526                                                 p += 2;
527                                 }
528                         }
529                         printk(KERN_INFO PFX "No PST tables match this cpuid "
530                                         "(0x%x)\n", etuple);
531                         printk(KERN_INFO PFX "This is indicative of a broken "
532                                         "BIOS.\n");
533
534                         return -EINVAL;
535                 }
536                 p++;
537         }
538
539         return -ENODEV;
540 }
541
542
543 static int powernow_target(struct cpufreq_policy *policy,
544                             unsigned int target_freq,
545                             unsigned int relation)
546 {
547         unsigned int newstate;
548
549         if (cpufreq_frequency_table_target(policy, powernow_table, target_freq,
550                                 relation, &newstate))
551                 return -EINVAL;
552
553         change_speed(newstate);
554
555         return 0;
556 }
557
558
559 static int powernow_verify(struct cpufreq_policy *policy)
560 {
561         return cpufreq_frequency_table_verify(policy, powernow_table);
562 }
563
564 /*
565  * We use the fact that the bus frequency is somehow
566  * a multiple of 100000/3 khz, then we compute sgtc according
567  * to this multiple.
568  * That way, we match more how AMD thinks all of that work.
569  * We will then get the same kind of behaviour already tested under
570  * the "well-known" other OS.
571  */
572 static int __cpuinit fixup_sgtc(void)
573 {
574         unsigned int sgtc;
575         unsigned int m;
576
577         m = fsb / 3333;
578         if ((m % 10) >= 5)
579                 m += 5;
580
581         m /= 10;
582
583         sgtc = 100 * m * latency;
584         sgtc = sgtc / 3;
585         if (sgtc > 0xfffff) {
586                 printk(KERN_WARNING PFX "SGTC too large %d\n", sgtc);
587                 sgtc = 0xfffff;
588         }
589         return sgtc;
590 }
591
592 static unsigned int powernow_get(unsigned int cpu)
593 {
594         union msr_fidvidstatus fidvidstatus;
595         unsigned int cfid;
596
597         if (cpu)
598                 return 0;
599         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
600         cfid = fidvidstatus.bits.CFID;
601
602         return fsb * fid_codes[cfid] / 10;
603 }
604
605
606 static int __cpuinit acer_cpufreq_pst(const struct dmi_system_id *d)
607 {
608         printk(KERN_WARNING PFX
609                 "%s laptop with broken PST tables in BIOS detected.\n",
610                 d->ident);
611         printk(KERN_WARNING PFX
612                 "You need to downgrade to 3A21 (09/09/2002), or try a newer "
613                 "BIOS than 3A71 (01/20/2003)\n");
614         printk(KERN_WARNING PFX
615                 "cpufreq scaling has been disabled as a result of this.\n");
616         return 0;
617 }
618
619 /*
620  * Some Athlon laptops have really fucked PST tables.
621  * A BIOS update is all that can save them.
622  * Mention this, and disable cpufreq.
623  */
624 static struct dmi_system_id __cpuinitdata powernow_dmi_table[] = {
625         {
626                 .callback = acer_cpufreq_pst,
627                 .ident = "Acer Aspire",
628                 .matches = {
629                         DMI_MATCH(DMI_SYS_VENDOR, "Insyde Software"),
630                         DMI_MATCH(DMI_BIOS_VERSION, "3A71"),
631                 },
632         },
633         { }
634 };
635
636 static int __cpuinit powernow_cpu_init(struct cpufreq_policy *policy)
637 {
638         union msr_fidvidstatus fidvidstatus;
639         int result;
640
641         if (policy->cpu != 0)
642                 return -ENODEV;
643
644         rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
645
646         recalibrate_cpu_khz();
647
648         fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.CFID];
649         if (!fsb) {
650                 printk(KERN_WARNING PFX "can not determine bus frequency\n");
651                 return -EINVAL;
652         }
653         dprintk("FSB: %3dMHz\n", fsb/1000);
654
655         if (dmi_check_system(powernow_dmi_table) || acpi_force) {
656                 printk(KERN_INFO PFX "PSB/PST known to be broken.  "
657                                 "Trying ACPI instead\n");
658                 result = powernow_acpi_init();
659         } else {
660                 result = powernow_decode_bios(fidvidstatus.bits.MFID,
661                                 fidvidstatus.bits.SVID);
662                 if (result) {
663                         printk(KERN_INFO PFX "Trying ACPI perflib\n");
664                         maximum_speed = 0;
665                         minimum_speed = -1;
666                         latency = 0;
667                         result = powernow_acpi_init();
668                         if (result) {
669                                 printk(KERN_INFO PFX
670                                         "ACPI and legacy methods failed\n");
671                         }
672                 } else {
673                         /* SGTC use the bus clock as timer */
674                         latency = fixup_sgtc();
675                         printk(KERN_INFO PFX "SGTC: %d\n", latency);
676                 }
677         }
678
679         if (result)
680                 return result;
681
682         printk(KERN_INFO PFX "Minimum speed %d MHz. Maximum speed %d MHz.\n",
683                                 minimum_speed/1000, maximum_speed/1000);
684
685         policy->cpuinfo.transition_latency =
686                 cpufreq_scale(2000000UL, fsb, latency);
687
688         policy->cur = powernow_get(0);
689
690         cpufreq_frequency_table_get_attr(powernow_table, policy->cpu);
691
692         return cpufreq_frequency_table_cpuinfo(policy, powernow_table);
693 }
694
695 static int powernow_cpu_exit(struct cpufreq_policy *policy)
696 {
697         cpufreq_frequency_table_put_attr(policy->cpu);
698
699 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
700         if (acpi_processor_perf) {
701                 acpi_processor_unregister_performance(acpi_processor_perf, 0);
702                 free_cpumask_var(acpi_processor_perf->shared_cpu_map);
703                 kfree(acpi_processor_perf);
704         }
705 #endif
706
707         kfree(powernow_table);
708         return 0;
709 }
710
711 static struct freq_attr *powernow_table_attr[] = {
712         &cpufreq_freq_attr_scaling_available_freqs,
713         NULL,
714 };
715
716 static struct cpufreq_driver powernow_driver = {
717         .verify         = powernow_verify,
718         .target         = powernow_target,
719         .get            = powernow_get,
720 #ifdef CONFIG_X86_POWERNOW_K7_ACPI
721         .bios_limit     = acpi_processor_get_bios_limit,
722 #endif
723         .init           = powernow_cpu_init,
724         .exit           = powernow_cpu_exit,
725         .name           = "powernow-k7",
726         .owner          = THIS_MODULE,
727         .attr           = powernow_table_attr,
728 };
729
730 static int __init powernow_init(void)
731 {
732         if (check_powernow() == 0)
733                 return -ENODEV;
734         return cpufreq_register_driver(&powernow_driver);
735 }
736
737
738 static void __exit powernow_exit(void)
739 {
740         cpufreq_unregister_driver(&powernow_driver);
741 }
742
743 module_param(acpi_force,  int, 0444);
744 MODULE_PARM_DESC(acpi_force, "Force ACPI to be used.");
745
746 MODULE_AUTHOR("Dave Jones <davej@redhat.com>");
747 MODULE_DESCRIPTION("Powernow driver for AMD K7 processors.");
748 MODULE_LICENSE("GPL");
749
750 late_initcall(powernow_init);
751 module_exit(powernow_exit);
752