summaryrefslogtreecommitdiff
path: root/drivers/cpufreq/powernow-k7.c
blob: 501d167368d2f22636d460ee7cf9f6b5973276c1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
/*
 *  AMD K7 Powernow driver.
 *  (C) 2003 Dave Jones on behalf of SuSE Labs.
 *  (C) 2003-2004 Dave Jones <davej@redhat.com>
 *
 *  Licensed under the terms of the GNU GPL License version 2.
 *  Based upon datasheets & sample CPUs kindly provided by AMD.
 *
 * Errata 5:
 *  CPU may fail to execute a FID/VID change in presence of interrupt.
 *  - We cli/sti on stepping A0 CPUs around the FID/VID transition.
 * Errata 15:
 *  CPU with half frequency multipliers may hang upon wakeup from disconnect.
 *  - We disable half multipliers if ACPI is used on A0 stepping CPUs.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/dmi.h>
#include <linux/timex.h>
#include <linux/io.h>

#include <asm/timer.h>		/* Needed for recalibrate_cpu_khz() */
#include <asm/msr.h>
#include <asm/system.h>
#include <asm/cpu_device_id.h>

#ifdef CONFIG_X86_POWERNOW_K7_ACPI
#include <linux/acpi.h>
#include <acpi/processor.h>
#endif

#include "powernow-k7.h"

#define PFX "powernow: "


struct psb_s {
	u8 signature[10];
	u8 tableversion;
	u8 flags;
	u16 settlingtime;
	u8 reserved1;
	u8 numpst;
};

struct pst_s {
	u32 cpuid;
	u8 fsbspeed;
	u8 maxfid;
	u8 startvid;
	u8 numpstates;
};

#ifdef CONFIG_X86_POWERNOW_K7_ACPI
union powernow_acpi_control_t {
	struct {
		unsigned long fid:5,
			vid:5,
			sgtc:20,
			res1:2;
	} bits;
	unsigned long val;
};
#endif

/* divide by 1000 to get VCore voltage in V. */
static const int mobile_vid_table[32] = {
    2000, 1950, 1900, 1850, 1800, 1750, 1700, 1650,
    1600, 1550, 1500, 1450, 1400, 1350, 1300, 0,
    1275, 1250, 1225, 1200, 1175, 1150, 1125, 1100,
    1075, 1050, 1025, 1000, 975, 950, 925, 0,
};

/* divide by 10 to get FID. */
static const int fid_codes[32] = {
    110, 115, 120, 125, 50, 55, 60, 65,
    70, 75, 80, 85, 90, 95, 100, 105,
    30, 190, 40, 200, 130, 135, 140, 210,
    150, 225, 160, 165, 170, 180, -1, -1,
};

/* This parameter is used in order to force ACPI instead of legacy method for
 * configuration purpose.
 */

static int acpi_force;

static struct cpufreq_frequency_table *powernow_table;

static unsigned int can_scale_bus;
static unsigned int can_scale_vid;
static unsigned int minimum_speed = -1;
static unsigned int maximum_speed;
static unsigned int number_scales;
static unsigned int fsb;
static unsigned int latency;
static char have_a0;

static int check_fsb(unsigned int fsbspeed)
{
	int delta;
	unsigned int f = fsb / 1000;

	delta = (fsbspeed > f) ? fsbspeed - f : f - fsbspeed;
	return delta < 5;
}

static const struct x86_cpu_id powernow_k7_cpuids[] = {
	{ X86_VENDOR_AMD, 7, },
	{}
};
MODULE_DEVICE_TABLE(x86cpu, powernow_k7_cpuids);

static int check_powernow(void)
{
	struct cpuinfo_x86 *c = &cpu_data(0);
	unsigned int maxei, eax, ebx, ecx, edx;

	if (!x86_match_cpu(powernow_k7_cpuids))
		return 0;

	/* Get maximum capabilities */
	maxei = cpuid_eax(0x80000000);
	if (maxei < 0x80000007) {	/* Any powernow info ? */
#ifdef MODULE
		printk(KERN_INFO PFX "No powernow capabilities detected\n");
#endif
		return 0;
	}

	if ((c->x86_model == 6) && (c->x86_mask == 0)) {
		printk(KERN_INFO PFX "K7 660[A0] core detected, "
				"enabling errata workarounds\n");
		have_a0 = 1;
	}

	cpuid(0x80000007, &eax, &ebx, &ecx, &edx);

	/* Check we can actually do something before we say anything.*/
	if (!(edx & (1 << 1 | 1 << 2)))
		return 0;

	printk(KERN_INFO PFX "PowerNOW! Technology present. Can scale: ");

	if (edx & 1 << 1) {
		printk("frequency");
		can_scale_bus = 1;
	}

	if ((edx & (1 << 1 | 1 << 2)) == 0x6)
		printk(" and ");

	if (edx & 1 << 2) {
		printk("voltage");
		can_scale_vid = 1;
	}

	printk(".\n");
	return 1;
}

#ifdef CONFIG_X86_POWERNOW_K7_ACPI
static void invalidate_entry(unsigned int entry)
{
	powernow_table[entry].frequency = CPUFREQ_ENTRY_INVALID;
}
#endif

static int get_ranges(unsigned char *pst)
{
	unsigned int j;
	unsigned int speed;
	u8 fid, vid;

	powernow_table = kzalloc((sizeof(struct cpufreq_frequency_table) *
				(number_scales + 1)), GFP_KERNEL);
	if (!powernow_table)
		return -ENOMEM;

	for (j = 0 ; j < number_scales; j++) {
		fid = *pst++;

		powernow_table[j].frequency = (fsb * fid_codes[fid]) / 10;
		powernow_table[j].index = fid; /* lower 8 bits */

		speed = powernow_table[j].frequency;

		if ((fid_codes[fid] % 10) == 5) {
#ifdef CONFIG_X86_POWERNOW_K7_ACPI
			if (have_a0 == 1)
				invalidate_entry(j);
#endif
		}

		if (speed < minimum_speed)
			minimum_speed = speed;
		if (speed > maximum_speed)
			maximum_speed = speed;

		vid = *pst++;
		powernow_table[j].index |= (vid << 8); /* upper 8 bits */

		pr_debug("   FID: 0x%x (%d.%dx [%dMHz])  "
			 "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
			 fid_codes[fid] % 10, speed/1000, vid,
			 mobile_vid_table[vid]/1000,
			 mobile_vid_table[vid]%1000);
	}
	powernow_table[number_scales].frequency = CPUFREQ_TABLE_END;
	powernow_table[number_scales].index = 0;

	return 0;
}


static void change_FID(int fid)
{
	union msr_fidvidctl fidvidctl;

	rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
	if (fidvidctl.bits.FID != fid) {
		fidvidctl.bits.SGTC = latency;
		fidvidctl.bits.FID = fid;
		fidvidctl.bits.VIDC = 0;
		fidvidctl.bits.FIDC = 1;
		wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
	}
}


static void change_VID(int vid)
{
	union msr_fidvidctl fidvidctl;

	rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
	if (fidvidctl.bits.VID != vid) {
		fidvidctl.bits.SGTC = latency;
		fidvidctl.bits.VID = vid;
		fidvidctl.bits.FIDC = 0;
		fidvidctl.bits.VIDC = 1;
		wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
	}
}


static void change_speed(unsigned int index)
{
	u8 fid, vid;
	struct cpufreq_freqs freqs;
	union msr_fidvidstatus fidvidstatus;
	int cfid;

	/* fid are the lower 8 bits of the index we stored into
	 * the cpufreq frequency table in powernow_decode_bios,
	 * vid are the upper 8 bits.
	 */

	fid = powernow_table[index].index & 0xFF;
	vid = (powernow_table[index].index & 0xFF00) >> 8;

	freqs.cpu = 0;

	rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
	cfid = fidvidstatus.bits.CFID;
	freqs.old = fsb * fid_codes[cfid] / 10;

	freqs.new = powernow_table[index].frequency;

	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);

	/* Now do the magic poking into the MSRs.  */

	if (have_a0 == 1)	/* A0 errata 5 */
		local_irq_disable();

	if (freqs.old > freqs.new) {
		/* Going down, so change FID first */
		change_FID(fid);
		change_VID(vid);
	} else {
		/* Going up, so change VID first */
		change_VID(vid);
		change_FID(fid);
	}


	if (have_a0 == 1)
		local_irq_enable();

	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
}


#ifdef CONFIG_X86_POWERNOW_K7_ACPI

static struct acpi_processor_performance *acpi_processor_perf;

static int powernow_acpi_init(void)
{
	int i;
	int retval = 0;
	union powernow_acpi_control_t pc;

	if (acpi_processor_perf != NULL && powernow_table != NULL) {
		retval = -EINVAL;
		goto err0;
	}

	acpi_processor_perf = kzalloc(sizeof(struct acpi_processor_performance),
				      GFP_KERNEL);
	if (!acpi_processor_perf) {
		retval = -ENOMEM;
		goto err0;
	}

	if (!zalloc_cpumask_var(&acpi_processor_perf->shared_cpu_map,
								GFP_KERNEL)) {
		retval = -ENOMEM;
		goto err05;
	}

	if (acpi_processor_register_performance(acpi_processor_perf, 0)) {
		retval = -EIO;
		goto err1;
	}

	if (acpi_processor_perf->control_register.space_id !=
			ACPI_ADR_SPACE_FIXED_HARDWARE) {
		retval = -ENODEV;
		goto err2;
	}

	if (acpi_processor_perf->status_register.space_id !=
			ACPI_ADR_SPACE_FIXED_HARDWARE) {
		retval = -ENODEV;
		goto err2;
	}

	number_scales = acpi_processor_perf->state_count;

	if (number_scales < 2) {
		retval = -ENODEV;
		goto err2;
	}

	powernow_table = kzalloc((sizeof(struct cpufreq_frequency_table) *
				(number_scales + 1)), GFP_KERNEL);
	if (!powernow_table) {
		retval = -ENOMEM;
		goto err2;
	}

	pc.val = (unsigned long) acpi_processor_perf->states[0].control;
	for (i = 0; i < number_scales; i++) {
		u8 fid, vid;
		struct acpi_processor_px *state =
			&acpi_processor_perf->states[i];
		unsigned int speed, speed_mhz;

		pc.val = (unsigned long) state->control;
		pr_debug("acpi:  P%d: %d MHz %d mW %d uS control %08x SGTC %d\n",
			 i,
			 (u32) state->core_frequency,
			 (u32) state->power,
			 (u32) state->transition_latency,
			 (u32) state->control,
			 pc.bits.sgtc);

		vid = pc.bits.vid;
		fid = pc.bits.fid;

		powernow_table[i].frequency = fsb * fid_codes[fid] / 10;
		powernow_table[i].index = fid; /* lower 8 bits */
		powernow_table[i].index |= (vid << 8); /* upper 8 bits */

		speed = powernow_table[i].frequency;
		speed_mhz = speed / 1000;

		/* processor_perflib will multiply the MHz value by 1000 to
		 * get a KHz value (e.g. 1266000). However, powernow-k7 works
		 * with true KHz values (e.g. 1266768). To ensure that all
		 * powernow frequencies are available, we must ensure that
		 * ACPI doesn't restrict them, so we round up the MHz value
		 * to ensure that perflib's computed KHz value is greater than
		 * or equal to powernow's KHz value.
		 */
		if (speed % 1000 > 0)
			speed_mhz++;

		if ((fid_codes[fid] % 10) == 5) {
			if (have_a0 == 1)
				invalidate_entry(i);
		}

		pr_debug("   FID: 0x%x (%d.%dx [%dMHz])  "
			 "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
			 fid_codes[fid] % 10, speed_mhz, vid,
			 mobile_vid_table[vid]/1000,
			 mobile_vid_table[vid]%1000);

		if (state->core_frequency != speed_mhz) {
			state->core_frequency = speed_mhz;
			pr_debug("   Corrected ACPI frequency to %d\n",
				speed_mhz);
		}

		if (latency < pc.bits.sgtc)
			latency = pc.bits.sgtc;

		if (speed < minimum_speed)
			minimum_speed = speed;
		if (speed > maximum_speed)
			maximum_speed = speed;
	}

	powernow_table[i].frequency = CPUFREQ_TABLE_END;
	powernow_table[i].index = 0;

	/* notify BIOS that we exist */
	acpi_processor_notify_smm(THIS_MODULE);

	return 0;

err2:
	acpi_processor_unregister_performance(acpi_processor_perf, 0);
err1:
	free_cpumask_var(acpi_processor_perf->shared_cpu_map);
err05:
	kfree(acpi_processor_perf);
err0:
	printk(KERN_WARNING PFX "ACPI perflib can not be used on "
			"this platform\n");
	acpi_processor_perf = NULL;
	return retval;
}
#else
static int powernow_acpi_init(void)
{
	printk(KERN_INFO PFX "no support for ACPI processor found."
	       "  Please recompile your kernel with ACPI processor\n");
	return -EINVAL;
}
#endif

static void print_pst_entry(struct pst_s *pst, unsigned int j)
{
	pr_debug("PST:%d (@%p)\n", j, pst);
	pr_debug(" cpuid: 0x%x  fsb: %d  maxFID: 0x%x  startvid: 0x%x\n",
		pst->cpuid, pst->fsbspeed, pst->maxfid, pst->startvid);
}

static int powernow_decode_bios(int maxfid, int startvid)
{
	struct psb_s *psb;
	struct pst_s *pst;
	unsigned int i, j;
	unsigned char *p;
	unsigned int etuple;
	unsigned int ret;

	etuple = cpuid_eax(0x80000001);

	for (i = 0xC0000; i < 0xffff0 ; i += 16) {

		p = phys_to_virt(i);

		if (memcmp(p, "AMDK7PNOW!",  10) == 0) {
			pr_debug("Found PSB header at %p\n", p);
			psb = (struct psb_s *) p;
			pr_debug("Table version: 0x%x\n", psb->tableversion);
			if (psb->tableversion != 0x12) {
				printk(KERN_INFO PFX "Sorry, only v1.2 tables"
						" supported right now\n");
				return -ENODEV;
			}

			pr_debug("Flags: 0x%x\n", psb->flags);
			if ((psb->flags & 1) == 0)
				pr_debug("Mobile voltage regulator\n");
			else
				pr_debug("Desktop voltage regulator\n");

			latency = psb->settlingtime;
			if (latency < 100) {
				printk(KERN_INFO PFX "BIOS set settling time "
						"to %d microseconds. "
						"Should be at least 100. "
						"Correcting.\n", latency);
				latency = 100;
			}
			pr_debug("Settling Time: %d microseconds.\n",
					psb->settlingtime);
			pr_debug("Has %d PST tables. (Only dumping ones "
					"relevant to this CPU).\n",
					psb->numpst);

			p += sizeof(struct psb_s);

			pst = (struct pst_s *) p;

			for (j = 0; j < psb->numpst; j++) {
				pst = (struct pst_s *) p;
				number_scales = pst->numpstates;

				if ((etuple == pst->cpuid) &&
				    check_fsb(pst->fsbspeed) &&
				    (maxfid == pst->maxfid) &&
				    (startvid == pst->startvid)) {
					print_pst_entry(pst, j);
					p = (char *)pst + sizeof(struct pst_s);
					ret = get_ranges(p);
					return ret;
				} else {
					unsigned int k;
					p = (char *)pst + sizeof(struct pst_s);
					for (k = 0; k < number_scales; k++)
						p += 2;
				}
			}
			printk(KERN_INFO PFX "No PST tables match this cpuid "
					"(0x%x)\n", etuple);
			printk(KERN_INFO PFX "This is indicative of a broken "
					"BIOS.\n");

			return -EINVAL;
		}
		p++;
	}

	return -ENODEV;
}


static int powernow_target(struct cpufreq_policy *policy,
			    unsigned int target_freq,
			    unsigned int relation)
{
	unsigned int newstate;

	if (cpufreq_frequency_table_target(policy, powernow_table, target_freq,
				relation, &newstate))
		return -EINVAL;

	change_speed(newstate);

	return 0;
}


static int powernow_verify(struct cpufreq_policy *policy)
{
	return cpufreq_frequency_table_verify(policy, powernow_table);
}

/*
 * We use the fact that the bus frequency is somehow
 * a multiple of 100000/3 khz, then we compute sgtc according
 * to this multiple.
 * That way, we match more how AMD thinks all of that work.
 * We will then get the same kind of behaviour already tested under
 * the "well-known" other OS.
 */
static int __cpuinit fixup_sgtc(void)
{
	unsigned int sgtc;
	unsigned int m;

	m = fsb / 3333;
	if ((m % 10) >= 5)
		m += 5;

	m /= 10;

	sgtc = 100 * m * latency;
	sgtc = sgtc / 3;
	if (sgtc > 0xfffff) {
		printk(KERN_WARNING PFX "SGTC too large %d\n", sgtc);
		sgtc = 0xfffff;
	}
	return sgtc;
}

static unsigned int powernow_get(unsigned int cpu)
{
	union msr_fidvidstatus fidvidstatus;
	unsigned int cfid;

	if (cpu)
		return 0;
	rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
	cfid = fidvidstatus.bits.CFID;

	return fsb * fid_codes[cfid] / 10;
}


static int __cpuinit acer_cpufreq_pst(const struct dmi_system_id *d)
{
	printk(KERN_WARNING PFX
		"%s laptop with broken PST tables in BIOS detected.\n",
		d->ident);
	printk(KERN_WARNING PFX
		"You need to downgrade to 3A21 (09/09/2002), or try a newer "
		"BIOS than 3A71 (01/20/2003)\n");
	printk(KERN_WARNING PFX
		"cpufreq scaling has been disabled as a result of this.\n");
	return 0;
}

/*
 * Some Athlon laptops have really fucked PST tables.
 * A BIOS update is all that can save them.
 * Mention this, and disable cpufreq.
 */
static struct dmi_system_id __cpuinitdata powernow_dmi_table[] = {
	{
		.callback = acer_cpufreq_pst,
		.ident = "Acer Aspire",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Insyde Software"),
			DMI_MATCH(DMI_BIOS_VERSION, "3A71"),
		},
	},
	{ }
};

static int __cpuinit powernow_cpu_init(struct cpufreq_policy *policy)
{
	union msr_fidvidstatus fidvidstatus;
	int result;

	if (policy->cpu != 0)
		return -ENODEV;

	rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);

	recalibrate_cpu_khz();

	fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.CFID];
	if (!fsb) {
		printk(KERN_WARNING PFX "can not determine bus frequency\n");
		return -EINVAL;
	}
	pr_debug("FSB: %3dMHz\n", fsb/1000);

	if (dmi_check_system(powernow_dmi_table) || acpi_force) {
		printk(KERN_INFO PFX "PSB/PST known to be broken.  "
				"Trying ACPI instead\n");
		result = powernow_acpi_init();
	} else {
		result = powernow_decode_bios(fidvidstatus.bits.MFID,
				fidvidstatus.bits.SVID);
		if (result) {
			printk(KERN_INFO PFX "Trying ACPI perflib\n");
			maximum_speed = 0;
			minimum_speed = -1;
			latency = 0;
			result = powernow_acpi_init();
			if (result) {
				printk(KERN_INFO PFX
					"ACPI and legacy methods failed\n");
			}
		} else {
			/* SGTC use the bus clock as timer */
			latency = fixup_sgtc();
			printk(KERN_INFO PFX "SGTC: %d\n", latency);
		}
	}

	if (result)
		return result;

	printk(KERN_INFO PFX "Minimum speed %d MHz. Maximum speed %d MHz.\n",
				minimum_speed/1000, maximum_speed/1000);

	policy->cpuinfo.transition_latency =
		cpufreq_scale(2000000UL, fsb, latency);

	policy->cur = powernow_get(0);

	cpufreq_frequency_table_get_attr(powernow_table, policy->cpu);

	return cpufreq_frequency_table_cpuinfo(policy, powernow_table);
}

static int powernow_cpu_exit(struct cpufreq_policy *policy)
{
	cpufreq_frequency_table_put_attr(policy->cpu);

#ifdef CONFIG_X86_POWERNOW_K7_ACPI
	if (acpi_processor_perf) {
		acpi_processor_unregister_performance(acpi_processor_perf, 0);
		free_cpumask_var(acpi_processor_perf->shared_cpu_map);
		kfree(acpi_processor_perf);
	}
#endif

	kfree(powernow_table);
	return 0;
}

static struct freq_attr *powernow_table_attr[] = {
	&cpufreq_freq_attr_scaling_available_freqs,
	NULL,
};

static struct cpufreq_driver powernow_driver = {
	.verify		= powernow_verify,
	.target		= powernow_target,
	.get		= powernow_get,
#ifdef CONFIG_X86_POWERNOW_K7_ACPI
	.bios_limit	= acpi_processor_get_bios_limit,
#endif
	.init		= powernow_cpu_init,
	.exit		= powernow_cpu_exit,
	.name		= "powernow-k7",
	.owner		= THIS_MODULE,
	.attr		= powernow_table_attr,
};

static int __init powernow_init(void)
{
	if (check_powernow() == 0)
		return -ENODEV;
	return cpufreq_register_driver(&powernow_driver);
}


static void __exit powernow_exit(void)
{
	cpufreq_unregister_driver(&powernow_driver);
}

module_param(acpi_force,  int, 0444);
MODULE_PARM_DESC(acpi_force, "Force ACPI to be used.");

MODULE_AUTHOR("Dave Jones <davej@redhat.com>");
MODULE_DESCRIPTION("Powernow driver for AMD K7 processors.");
MODULE_LICENSE("GPL");

late_initcall(powernow_init);
module_exit(powernow_exit);