/arch/i386/kernel/cpu/cpufreq/powernow-k7.c

  1/*
  2 *  AMD K7 Powernow driver.
  3 *  (C) 2003 Dave Jones <davej@codemonkey.org.uk> 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: Processor may fail to execute a FID/VID change in presence of interrupt.
 10 * - We cli/sti on stepping A0 CPUs around the FID/VID transition.
 11 * Errata 15: Processors with half frequency multipliers may hang upon wakeup from disconnect.
 12 * - We disable half multipliers if ACPI is used on A0 stepping CPUs.
 13 */
 14
 15#include <linux/config.h>
 16#include <linux/kernel.h>
 17#include <linux/module.h>
 18#include <linux/moduleparam.h>
 19#include <linux/init.h>
 20#include <linux/cpufreq.h>
 21#include <linux/slab.h>
 22#include <linux/string.h>
 23#include <linux/dmi.h>
 24
 25#include <asm/msr.h>
 26#include <asm/timex.h>
 27#include <asm/io.h>
 28#include <asm/system.h>
 29
 30#ifdef CONFIG_X86_POWERNOW_K7_ACPI
 31#include <linux/acpi.h>
 32#include <acpi/processor.h>
 33#endif
 34
 35#include "powernow-k7.h"
 36
 37#define PFX "powernow: "
 38
 39
 40struct psb_s {
 41	u8 signature[10];
 42	u8 tableversion;
 43	u8 flags;
 44	u16 settlingtime;
 45	u8 reserved1;
 46	u8 numpst;
 47};
 48
 49struct pst_s {
 50	u32 cpuid;
 51	u8 fsbspeed;
 52	u8 maxfid;
 53	u8 startvid;
 54	u8 numpstates;
 55};
 56
 57#ifdef CONFIG_X86_POWERNOW_K7_ACPI
 58union powernow_acpi_control_t {
 59	struct {
 60		unsigned long fid:5,
 61		vid:5,
 62		sgtc:20,
 63		res1:2;
 64	} bits;
 65	unsigned long val;
 66};
 67#endif
 68
 69#ifdef CONFIG_CPU_FREQ_DEBUG
 70/* divide by 1000 to get VCore voltage in V. */
 71static int mobile_vid_table[32] = {
 72    2000, 1950, 1900, 1850, 1800, 1750, 1700, 1650,
 73    1600, 1550, 1500, 1450, 1400, 1350, 1300, 0,
 74    1275, 1250, 1225, 1200, 1175, 1150, 1125, 1100,
 75    1075, 1050, 1025, 1000, 975, 950, 925, 0,
 76};
 77#endif
 78
 79/* divide by 10 to get FID. */
 80static 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
 91static int acpi_force;
 92
 93static struct cpufreq_frequency_table *powernow_table;
 94
 95static unsigned int can_scale_bus;
 96static unsigned int can_scale_vid;
 97static unsigned int minimum_speed=-1;
 98static unsigned int maximum_speed;
 99static unsigned int number_scales;
100static unsigned int fsb;
101static unsigned int latency;
102static char have_a0;
103
104#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "powernow-k7", msg)
105
106static int check_fsb(unsigned int fsbspeed)
107{
108	int delta;
109	unsigned int f = fsb / 1000;
110
111	delta = (fsbspeed > f) ? fsbspeed - f : f - fsbspeed;
112	return (delta < 5);
113}
114
115static int check_powernow(void)
116{
117	struct cpuinfo_x86 *c = cpu_data;
118	unsigned int maxei, eax, ebx, ecx, edx;
119
120	if ((c->x86_vendor != X86_VENDOR_AMD) || (c->x86 !=6)) {
121#ifdef MODULE
122		printk (KERN_INFO PFX "This module only works with AMD K7 CPUs\n");
123#endif
124		return 0;
125	}
126
127	/* Get maximum capabilities */
128	maxei = cpuid_eax (0x80000000);
129	if (maxei < 0x80000007) {	/* Any powernow info ? */
130#ifdef MODULE
131		printk (KERN_INFO PFX "No powernow capabilities detected\n");
132#endif
133		return 0;
134	}
135
136	if ((c->x86_model == 6) && (c->x86_mask == 0)) {
137		printk (KERN_INFO PFX "K7 660[A0] core detected, 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
167static int get_ranges (unsigned char *pst)
168{
169	unsigned int j;
170	unsigned int speed;
171	u8 fid, vid;
172
173	powernow_table = kmalloc((sizeof(struct cpufreq_frequency_table) * (number_scales + 1)), GFP_KERNEL);
174	if (!powernow_table)
175		return -ENOMEM;
176	memset(powernow_table, 0, (sizeof(struct cpufreq_frequency_table) * (number_scales + 1)));
177
178	for (j=0 ; j < number_scales; j++) {
179		fid = *pst++;
180
181		powernow_table[j].frequency = (fsb * fid_codes[fid]) / 10;
182		powernow_table[j].index = fid; /* lower 8 bits */
183
184		speed = powernow_table[j].frequency;
185
186		if ((fid_codes[fid] % 10)==5) {
187#ifdef CONFIG_X86_POWERNOW_K7_ACPI
188			if (have_a0 == 1)
189				powernow_table[j].frequency = CPUFREQ_ENTRY_INVALID;
190#endif
191		}
192
193		if (speed < minimum_speed)
194			minimum_speed = speed;
195		if (speed > maximum_speed)
196			maximum_speed = speed;
197
198		vid = *pst++;
199		powernow_table[j].index |= (vid << 8); /* upper 8 bits */
200
201		dprintk ("   FID: 0x%x (%d.%dx [%dMHz])  "
202			 "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10, 
203			 fid_codes[fid] % 10, speed/1000, vid,	
204			 mobile_vid_table[vid]/1000,
205			 mobile_vid_table[vid]%1000);
206	}
207	powernow_table[number_scales].frequency = CPUFREQ_TABLE_END;
208	powernow_table[number_scales].index = 0;
209
210	return 0;
211}
212
213
214static void change_FID(int fid)
215{
216	union msr_fidvidctl fidvidctl;
217
218	rdmsrl (MSR_K7_FID_VID_CTL, fidvidctl.val);
219	if (fidvidctl.bits.FID != fid) {
220		fidvidctl.bits.SGTC = latency;
221		fidvidctl.bits.FID = fid;
222		fidvidctl.bits.VIDC = 0;
223		fidvidctl.bits.FIDC = 1;
224		wrmsrl (MSR_K7_FID_VID_CTL, fidvidctl.val);
225	}
226}
227
228
229static void change_VID(int vid)
230{
231	union msr_fidvidctl fidvidctl;
232
233	rdmsrl (MSR_K7_FID_VID_CTL, fidvidctl.val);
234	if (fidvidctl.bits.VID != vid) {
235		fidvidctl.bits.SGTC = latency;
236		fidvidctl.bits.VID = vid;
237		fidvidctl.bits.FIDC = 0;
238		fidvidctl.bits.VIDC = 1;
239		wrmsrl (MSR_K7_FID_VID_CTL, fidvidctl.val);
240	}
241}
242
243
244static void change_speed (unsigned int index)
245{
246	u8 fid, vid;
247	struct cpufreq_freqs freqs;
248	union msr_fidvidstatus fidvidstatus;
249	int cfid;
250
251	/* fid are the lower 8 bits of the index we stored into
252	 * the cpufreq frequency table in powernow_decode_bios,
253	 * vid are the upper 8 bits.
254	 */
255
256	fid = powernow_table[index].index & 0xFF;
257	vid = (powernow_table[index].index & 0xFF00) >> 8;
258
259	freqs.cpu = 0;
260
261	rdmsrl (MSR_K7_FID_VID_STATUS, fidvidstatus.val);
262	cfid = fidvidstatus.bits.CFID;
263	freqs.old = fsb * fid_codes[cfid] / 10;
264
265	freqs.new = powernow_table[index].frequency;
266
267	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
268
269	/* Now do the magic poking into the MSRs.  */
270
271	if (have_a0 == 1)	/* A0 errata 5 */
272		local_irq_disable();
273
274	if (freqs.old > freqs.new) {
275		/* Going down, so change FID first */
276		change_FID(fid);
277		change_VID(vid);
278	} else {
279		/* Going up, so change VID first */
280		change_VID(vid);
281		change_FID(fid);
282	}
283
284
285	if (have_a0 == 1)
286		local_irq_enable();
287
288	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
289}
290
291
292#ifdef CONFIG_X86_POWERNOW_K7_ACPI
293
294static struct acpi_processor_performance *acpi_processor_perf;
295
296static int powernow_acpi_init(void)
297{
298	int i;
299	int retval = 0;
300	union powernow_acpi_control_t pc;
301
302	if (acpi_processor_perf != NULL && powernow_table != NULL) {
303		retval = -EINVAL;
304		goto err0;
305	}
306
307	acpi_processor_perf = kmalloc(sizeof(struct acpi_processor_performance),
308				      GFP_KERNEL);
309
310	if (!acpi_processor_perf) {
311		retval = -ENOMEM;
312		goto err0;
313	}
314
315	memset(acpi_processor_perf, 0, sizeof(struct acpi_processor_performance));
316
317	if (acpi_processor_register_performance(acpi_processor_perf, 0)) {
318		retval = -EIO;
319		goto err1;
320	}
321
322	if (acpi_processor_perf->control_register.space_id != ACPI_ADR_SPACE_FIXED_HARDWARE) {
323		retval = -ENODEV;
324		goto err2;
325	}
326
327	if (acpi_processor_perf->status_register.space_id != ACPI_ADR_SPACE_FIXED_HARDWARE) {
328		retval = -ENODEV;
329		goto err2;
330	}
331
332	number_scales = acpi_processor_perf->state_count;
333
334	if (number_scales < 2) {
335		retval = -ENODEV;
336		goto err2;
337	}
338
339	powernow_table = kmalloc((number_scales + 1) * (sizeof(struct cpufreq_frequency_table)), GFP_KERNEL);
340	if (!powernow_table) {
341		retval = -ENOMEM;
342		goto err2;
343	}
344
345	memset(powernow_table, 0, ((number_scales + 1) * sizeof(struct cpufreq_frequency_table)));
346
347	pc.val = (unsigned long) acpi_processor_perf->states[0].control;
348	for (i = 0; i < number_scales; i++) {
349		u8 fid, vid;
350		unsigned int speed;
351
352		pc.val = (unsigned long) acpi_processor_perf->states[i].control;
353		dprintk ("acpi:  P%d: %d MHz %d mW %d uS control %08x SGTC %d\n",
354			 i,
355			 (u32) acpi_processor_perf->states[i].core_frequency,
356			 (u32) acpi_processor_perf->states[i].power,
357			 (u32) acpi_processor_perf->states[i].transition_latency,
358			 (u32) acpi_processor_perf->states[i].control,
359			 pc.bits.sgtc);
360
361		vid = pc.bits.vid;
362		fid = pc.bits.fid;
363
364		powernow_table[i].frequency = fsb * fid_codes[fid] / 10;
365		powernow_table[i].index = fid; /* lower 8 bits */
366		powernow_table[i].index |= (vid << 8); /* upper 8 bits */
367
368		speed = powernow_table[i].frequency;
369
370		if ((fid_codes[fid] % 10)==5) {
371			if (have_a0 == 1)
372				powernow_table[i].frequency = CPUFREQ_ENTRY_INVALID;
373		}
374
375		dprintk ("   FID: 0x%x (%d.%dx [%dMHz])  "
376			 "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10, 
377			 fid_codes[fid] % 10, speed/1000, vid,	
378			 mobile_vid_table[vid]/1000,
379			 mobile_vid_table[vid]%1000);
380
381		if (latency < pc.bits.sgtc)
382			latency = pc.bits.sgtc;
383
384		if (speed < minimum_speed)
385			minimum_speed = speed;
386		if (speed > maximum_speed)
387			maximum_speed = speed;
388	}
389
390	powernow_table[i].frequency = CPUFREQ_TABLE_END;
391	powernow_table[i].index = 0;
392
393	/* notify BIOS that we exist */
394	acpi_processor_notify_smm(THIS_MODULE);
395
396	return 0;
397
398err2:
399	acpi_processor_unregister_performance(acpi_processor_perf, 0);
400err1:
401	kfree(acpi_processor_perf);
402err0:
403	printk(KERN_WARNING PFX "ACPI perflib can not be used in this platform\n");
404	acpi_processor_perf = NULL;
405	return retval;
406}
407#else
408static int powernow_acpi_init(void)
409{
410	printk(KERN_INFO PFX "no support for ACPI processor found."
411	       "  Please recompile your kernel with ACPI processor\n");
412	return -EINVAL;
413}
414#endif
415
416static int powernow_decode_bios (int maxfid, int startvid)
417{
418	struct psb_s *psb;
419	struct pst_s *pst;
420	unsigned int i, j;
421	unsigned char *p;
422	unsigned int etuple;
423	unsigned int ret;
424
425	etuple = cpuid_eax(0x80000001);
426
427	for (i=0xC0000; i < 0xffff0 ; i+=16) {
428
429		p = phys_to_virt(i);
430
431		if (memcmp(p, "AMDK7PNOW!",  10) == 0){
432			dprintk ("Found PSB header at %p\n", p);
433			psb = (struct psb_s *) p;
434			dprintk ("Table version: 0x%x\n", psb->tableversion);
435			if (psb->tableversion != 0x12) {
436				printk (KERN_INFO PFX "Sorry, only v1.2 tables supported right now\n");
437				return -ENODEV;
438			}
439
440			dprintk ("Flags: 0x%x\n", psb->flags);
441			if ((psb->flags & 1)==0) {
442				dprintk ("Mobile voltage regulator\n");
443			} else {
444				dprintk ("Desktop voltage regulator\n");
445			}
446
447			latency = psb->settlingtime;
448			if (latency < 100) {
449				printk (KERN_INFO PFX "BIOS set settling time to %d microseconds."
450						"Should be at least 100. Correcting.\n", latency);
451				latency = 100;
452			}
453			dprintk ("Settling Time: %d microseconds.\n", psb->settlingtime);
454			dprintk ("Has %d PST tables. (Only dumping ones relevant to this CPU).\n", psb->numpst);
455
456			p += sizeof (struct psb_s);
457
458			pst = (struct pst_s *) p;
459
460			for (i = 0 ; i <psb->numpst; i++) {
461				pst = (struct pst_s *) p;
462				number_scales = pst->numpstates;
463
464				if ((etuple == pst->cpuid) && check_fsb(pst->fsbspeed) &&
465				    (maxfid==pst->maxfid) && (startvid==pst->startvid))
466				{
467					dprintk ("PST:%d (@%p)\n", i, pst);
468					dprintk (" cpuid: 0x%x  fsb: %d  maxFID: 0x%x  startvid: 0x%x\n", 
469						 pst->cpuid, pst->fsbspeed, pst->maxfid, pst->startvid);
470
471					ret = get_ranges ((char *) pst + sizeof (struct pst_s));
472					return ret;
473
474				} else {
475					p = (char *) pst + sizeof (struct pst_s);
476					for (j=0 ; j < number_scales; j++)
477						p+=2;
478				}
479			}
480			printk (KERN_INFO PFX "No PST tables match this cpuid (0x%x)\n", etuple);
481			printk (KERN_INFO PFX "This is indicative of a broken BIOS.\n");
482
483			return -EINVAL;
484		}
485		p++;
486	}
487
488	return -ENODEV;
489}
490
491
492static int powernow_target (struct cpufreq_policy *policy,
493			    unsigned int target_freq,
494			    unsigned int relation)
495{
496	unsigned int newstate;
497
498	if (cpufreq_frequency_table_target(policy, powernow_table, target_freq, relation, &newstate))
499		return -EINVAL;
500
501	change_speed(newstate);
502
503	return 0;
504}
505
506
507static int powernow_verify (struct cpufreq_policy *policy)
508{
509	return cpufreq_frequency_table_verify(policy, powernow_table);
510}
511
512/*
513 * We use the fact that the bus frequency is somehow
514 * a multiple of 100000/3 khz, then we compute sgtc according
515 * to this multiple.
516 * That way, we match more how AMD thinks all of that work.
517 * We will then get the same kind of behaviour already tested under
518 * the "well-known" other OS.
519 */
520static int __init fixup_sgtc(void)
521{
522	unsigned int sgtc;
523	unsigned int m;
524
525	m = fsb / 3333;
526	if ((m % 10) >= 5)
527		m += 5;
528
529	m /= 10;
530
531	sgtc = 100 * m * latency;
532	sgtc = sgtc / 3;
533	if (sgtc > 0xfffff) {
534		printk(KERN_WARNING PFX "SGTC too large %d\n", sgtc);
535		sgtc = 0xfffff;
536	}
537	return sgtc;
538}
539
540static unsigned int powernow_get(unsigned int cpu)
541{
542	union msr_fidvidstatus fidvidstatus;
543	unsigned int cfid;
544
545	if (cpu)
546		return 0;
547	rdmsrl (MSR_K7_FID_VID_STATUS, fidvidstatus.val);
548	cfid = fidvidstatus.bits.CFID;
549
550	return (fsb * fid_codes[cfid] / 10);
551}
552
553
554static int __init acer_cpufreq_pst(struct dmi_system_id *d)
555{
556	printk(KERN_WARNING "%s laptop with broken PST tables in BIOS detected.\n", d->ident);
557	printk(KERN_WARNING "You need to downgrade to 3A21 (09/09/2002), or try a newer BIOS than 3A71 (01/20/2003)\n");
558	printk(KERN_WARNING "cpufreq scaling has been disabled as a result of this.\n");
559	return 0;
560}
561
562/*
563 * Some Athlon laptops have really fucked PST tables.
564 * A BIOS update is all that can save them.
565 * Mention this, and disable cpufreq.
566 */
567static struct dmi_system_id __initdata powernow_dmi_table[] = {
568	{
569		.callback = acer_cpufreq_pst,
570		.ident = "Acer Aspire",
571		.matches = {
572			DMI_MATCH(DMI_SYS_VENDOR, "Insyde Software"),
573			DMI_MATCH(DMI_BIOS_VERSION, "3A71"),
574		},
575	},
576	{ }
577};
578
579static int __init powernow_cpu_init (struct cpufreq_policy *policy)
580{
581	union msr_fidvidstatus fidvidstatus;
582	int result;
583
584	if (policy->cpu != 0)
585		return -ENODEV;
586
587	rdmsrl (MSR_K7_FID_VID_STATUS, fidvidstatus.val);
588
589	/* A K7 with powernow technology is set to max frequency by BIOS */
590	fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.MFID];
591	if (!fsb) {
592		printk(KERN_WARNING PFX "can not determine bus frequency\n");
593		return -EINVAL;
594	}
595	dprintk("FSB: %3d.%03d MHz\n", fsb/1000, fsb%1000);
596
597	if (dmi_check_system(powernow_dmi_table) || acpi_force) {
598		printk (KERN_INFO PFX "PSB/PST known to be broken.  Trying ACPI instead\n");
599		result = powernow_acpi_init();
600	} else {
601		result = powernow_decode_bios(fidvidstatus.bits.MFID, fidvidstatus.bits.SVID);
602		if (result) {
603			printk (KERN_INFO PFX "Trying ACPI perflib\n");
604			maximum_speed = 0;
605			minimum_speed = -1;
606			latency = 0;
607			result = powernow_acpi_init();
608			if (result) {
609				printk (KERN_INFO PFX "ACPI and legacy methods failed\n");
610				printk (KERN_INFO PFX "See http://www.codemonkey.org.uk/projects/cpufreq/powernow-k7.shtml\n");
611			}
612		} else {
613			/* SGTC use the bus clock as timer */
614			latency = fixup_sgtc();
615			printk(KERN_INFO PFX "SGTC: %d\n", latency);
616		}
617	}
618
619	if (result)
620		return result;
621
622	printk (KERN_INFO PFX "Minimum speed %d MHz. Maximum speed %d MHz.\n",
623				minimum_speed/1000, maximum_speed/1000);
624
625	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
626
627	policy->cpuinfo.transition_latency = cpufreq_scale(2000000UL, fsb, latency);
628
629	policy->cur = powernow_get(0);
630
631	cpufreq_frequency_table_get_attr(powernow_table, policy->cpu);
632
633	return cpufreq_frequency_table_cpuinfo(policy, powernow_table);
634}
635
636static int powernow_cpu_exit (struct cpufreq_policy *policy) {
637	cpufreq_frequency_table_put_attr(policy->cpu);
638
639#ifdef CONFIG_X86_POWERNOW_K7_ACPI
640	if (acpi_processor_perf) {
641		acpi_processor_unregister_performance(acpi_processor_perf, 0);
642		kfree(acpi_processor_perf);
643	}
644#endif
645
646	if (powernow_table)
647		kfree(powernow_table);
648
649	return 0;
650}
651
652static struct freq_attr* powernow_table_attr[] = {
653	&cpufreq_freq_attr_scaling_available_freqs,
654	NULL,
655};
656
657static struct cpufreq_driver powernow_driver = {
658	.verify	= powernow_verify,
659	.target	= powernow_target,
660	.get	= powernow_get,
661	.init	= powernow_cpu_init,
662	.exit	= powernow_cpu_exit,
663	.name	= "powernow-k7",
664	.owner	= THIS_MODULE,
665	.attr	= powernow_table_attr,
666};
667
668static int __init powernow_init (void)
669{
670	if (check_powernow()==0)
671		return -ENODEV;
672	return cpufreq_register_driver(&powernow_driver);
673}
674
675
676static void __exit powernow_exit (void)
677{
678	cpufreq_unregister_driver(&powernow_driver);
679}
680
681module_param(acpi_force,  int, 0444);
682MODULE_PARM_DESC(acpi_force, "Force ACPI to be used.");
683
684MODULE_AUTHOR ("Dave Jones <davej@codemonkey.org.uk>");
685MODULE_DESCRIPTION ("Powernow driver for AMD K7 processors.");
686MODULE_LICENSE ("GPL");
687
688late_initcall(powernow_init);
689module_exit(powernow_exit);
690