1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *  AMD K7 Powernow driver.
4 *  (C) 2003 Dave Jones on behalf of SuSE Labs.
5 *
6 *  Based upon datasheets & sample CPUs kindly provided by AMD.
7 *
8 * Errata 5:
9 *  CPU 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:
12 *  CPU with half frequency multipliers may hang upon wakeup from disconnect.
13 *  - We disable half multipliers if ACPI is used on A0 stepping CPUs.
14 */
15
16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18#include <linux/kernel.h>
19#include <linux/module.h>
20#include <linux/moduleparam.h>
21#include <linux/init.h>
22#include <linux/cpufreq.h>
23#include <linux/slab.h>
24#include <linux/string.h>
25#include <linux/dmi.h>
26#include <linux/timex.h>
27#include <linux/io.h>
28
29#include <asm/timer.h>		/* Needed for recalibrate_cpu_khz() */
30#include <asm/msr.h>
31#include <asm/cpu_device_id.h>
32
33#ifdef CONFIG_X86_POWERNOW_K7_ACPI
34#include <linux/acpi.h>
35#include <acpi/processor.h>
36#endif
37
38#include "powernow-k7.h"
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/* divide by 1000 to get VCore voltage in V. */
70static const int mobile_vid_table[32] = {
71    2000, 1950, 1900, 1850, 1800, 1750, 1700, 1650,
72    1600, 1550, 1500, 1450, 1400, 1350, 1300, 0,
73    1275, 1250, 1225, 1200, 1175, 1150, 1125, 1100,
74    1075, 1050, 1025, 1000, 975, 950, 925, 0,
75};
76
77/* divide by 10 to get FID. */
78static const int fid_codes[32] = {
79    110, 115, 120, 125, 50, 55, 60, 65,
80    70, 75, 80, 85, 90, 95, 100, 105,
81    30, 190, 40, 200, 130, 135, 140, 210,
82    150, 225, 160, 165, 170, 180, -1, -1,
83};
84
85/* This parameter is used in order to force ACPI instead of legacy method for
86 * configuration purpose.
87 */
88
89static int acpi_force;
90
91static struct cpufreq_frequency_table *powernow_table;
92
93static unsigned int can_scale_bus;
94static unsigned int can_scale_vid;
95static unsigned int minimum_speed = -1;
96static unsigned int maximum_speed;
97static unsigned int number_scales;
98static unsigned int fsb;
99static unsigned int latency;
100static char have_a0;
101
102static int check_fsb(unsigned int fsbspeed)
103{
104	int delta;
105	unsigned int f = fsb / 1000;
106
107	delta = (fsbspeed > f) ? fsbspeed - f : f - fsbspeed;
108	return delta < 5;
109}
110
111static const struct x86_cpu_id powernow_k7_cpuids[] = {
112	X86_MATCH_VENDOR_FAM(AMD, 6, NULL),
113	{}
114};
115MODULE_DEVICE_TABLE(x86cpu, powernow_k7_cpuids);
116
117static int check_powernow(void)
118{
119	struct cpuinfo_x86 *c = &cpu_data(0);
120	unsigned int maxei, eax, ebx, ecx, edx;
121
122	if (!x86_match_cpu(powernow_k7_cpuids))
123		return 0;
124
125	/* Get maximum capabilities */
126	maxei = cpuid_eax(0x80000000);
127	if (maxei < 0x80000007) {	/* Any powernow info ? */
128#ifdef MODULE
129		pr_info("No powernow capabilities detected\n");
130#endif
131		return 0;
132	}
133
134	if ((c->x86_model == 6) && (c->x86_stepping == 0)) {
135		pr_info("K7 660[A0] core detected, enabling errata workarounds\n");
136		have_a0 = 1;
137	}
138
139	cpuid(0x80000007, &eax, &ebx, &ecx, &edx);
140
141	/* Check we can actually do something before we say anything.*/
142	if (!(edx & (1 << 1 | 1 << 2)))
143		return 0;
144
145	pr_info("PowerNOW! Technology present. Can scale: ");
146
147	if (edx & 1 << 1) {
148		pr_cont("frequency");
149		can_scale_bus = 1;
150	}
151
152	if ((edx & (1 << 1 | 1 << 2)) == 0x6)
153		pr_cont(" and ");
154
155	if (edx & 1 << 2) {
156		pr_cont("voltage");
157		can_scale_vid = 1;
158	}
159
160	pr_cont("\n");
161	return 1;
162}
163
164#ifdef CONFIG_X86_POWERNOW_K7_ACPI
165static void invalidate_entry(unsigned int entry)
166{
167	powernow_table[entry].frequency = CPUFREQ_ENTRY_INVALID;
168}
169#endif
170
171static int get_ranges(unsigned char *pst)
172{
173	unsigned int j;
174	unsigned int speed;
175	u8 fid, vid;
176
177	powernow_table = kzalloc((sizeof(*powernow_table) *
178				(number_scales + 1)), GFP_KERNEL);
179	if (!powernow_table)
180		return -ENOMEM;
181
182	for (j = 0 ; j < number_scales; j++) {
183		fid = *pst++;
184
185		powernow_table[j].frequency = (fsb * fid_codes[fid]) / 10;
186		powernow_table[j].driver_data = fid; /* lower 8 bits */
187
188		speed = powernow_table[j].frequency;
189
190		if ((fid_codes[fid] % 10) == 5) {
191#ifdef CONFIG_X86_POWERNOW_K7_ACPI
192			if (have_a0 == 1)
193				invalidate_entry(j);
194#endif
195		}
196
197		if (speed < minimum_speed)
198			minimum_speed = speed;
199		if (speed > maximum_speed)
200			maximum_speed = speed;
201
202		vid = *pst++;
203		powernow_table[j].driver_data |= (vid << 8); /* upper 8 bits */
204
205		pr_debug("   FID: 0x%x (%d.%dx [%dMHz])  "
206			 "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
207			 fid_codes[fid] % 10, speed/1000, vid,
208			 mobile_vid_table[vid]/1000,
209			 mobile_vid_table[vid]%1000);
210	}
211	powernow_table[number_scales].frequency = CPUFREQ_TABLE_END;
212	powernow_table[number_scales].driver_data = 0;
213
214	return 0;
215}
216
217
218static void change_FID(int fid)
219{
220	union msr_fidvidctl fidvidctl;
221
222	rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
223	if (fidvidctl.bits.FID != fid) {
224		fidvidctl.bits.SGTC = latency;
225		fidvidctl.bits.FID = fid;
226		fidvidctl.bits.VIDC = 0;
227		fidvidctl.bits.FIDC = 1;
228		wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
229	}
230}
231
232
233static void change_VID(int vid)
234{
235	union msr_fidvidctl fidvidctl;
236
237	rdmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
238	if (fidvidctl.bits.VID != vid) {
239		fidvidctl.bits.SGTC = latency;
240		fidvidctl.bits.VID = vid;
241		fidvidctl.bits.FIDC = 0;
242		fidvidctl.bits.VIDC = 1;
243		wrmsrl(MSR_K7_FID_VID_CTL, fidvidctl.val);
244	}
245}
246
247
248static int powernow_target(struct cpufreq_policy *policy, unsigned int index)
249{
250	u8 fid, vid;
251	struct cpufreq_freqs freqs;
252	union msr_fidvidstatus fidvidstatus;
253	int cfid;
254
255	/* fid are the lower 8 bits of the index we stored into
256	 * the cpufreq frequency table in powernow_decode_bios,
257	 * vid are the upper 8 bits.
258	 */
259
260	fid = powernow_table[index].driver_data & 0xFF;
261	vid = (powernow_table[index].driver_data & 0xFF00) >> 8;
262
263	rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
264	cfid = fidvidstatus.bits.CFID;
265	freqs.old = fsb * fid_codes[cfid] / 10;
266
267	freqs.new = powernow_table[index].frequency;
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	return 0;
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 = kzalloc(sizeof(*acpi_processor_perf), GFP_KERNEL);
308	if (!acpi_processor_perf) {
309		retval = -ENOMEM;
310		goto err0;
311	}
312
313	if (!zalloc_cpumask_var(&acpi_processor_perf->shared_cpu_map,
314								GFP_KERNEL)) {
315		retval = -ENOMEM;
316		goto err05;
317	}
318
319	if (acpi_processor_register_performance(acpi_processor_perf, 0)) {
320		retval = -EIO;
321		goto err1;
322	}
323
324	if (acpi_processor_perf->control_register.space_id !=
325			ACPI_ADR_SPACE_FIXED_HARDWARE) {
326		retval = -ENODEV;
327		goto err2;
328	}
329
330	if (acpi_processor_perf->status_register.space_id !=
331			ACPI_ADR_SPACE_FIXED_HARDWARE) {
332		retval = -ENODEV;
333		goto err2;
334	}
335
336	number_scales = acpi_processor_perf->state_count;
337
338	if (number_scales < 2) {
339		retval = -ENODEV;
340		goto err2;
341	}
342
343	powernow_table = kzalloc((sizeof(*powernow_table) *
344				(number_scales + 1)), GFP_KERNEL);
345	if (!powernow_table) {
346		retval = -ENOMEM;
347		goto err2;
348	}
349
350	pc.val = (unsigned long) acpi_processor_perf->states[0].control;
351	for (i = 0; i < number_scales; i++) {
352		u8 fid, vid;
353		struct acpi_processor_px *state =
354			&acpi_processor_perf->states[i];
355		unsigned int speed, speed_mhz;
356
357		pc.val = (unsigned long) state->control;
358		pr_debug("acpi:  P%d: %d MHz %d mW %d uS control %08x SGTC %d\n",
359			 i,
360			 (u32) state->core_frequency,
361			 (u32) state->power,
362			 (u32) state->transition_latency,
363			 (u32) state->control,
364			 pc.bits.sgtc);
365
366		vid = pc.bits.vid;
367		fid = pc.bits.fid;
368
369		powernow_table[i].frequency = fsb * fid_codes[fid] / 10;
370		powernow_table[i].driver_data = fid; /* lower 8 bits */
371		powernow_table[i].driver_data |= (vid << 8); /* upper 8 bits */
372
373		speed = powernow_table[i].frequency;
374		speed_mhz = speed / 1000;
375
376		/* processor_perflib will multiply the MHz value by 1000 to
377		 * get a KHz value (e.g. 1266000). However, powernow-k7 works
378		 * with true KHz values (e.g. 1266768). To ensure that all
379		 * powernow frequencies are available, we must ensure that
380		 * ACPI doesn't restrict them, so we round up the MHz value
381		 * to ensure that perflib's computed KHz value is greater than
382		 * or equal to powernow's KHz value.
383		 */
384		if (speed % 1000 > 0)
385			speed_mhz++;
386
387		if ((fid_codes[fid] % 10) == 5) {
388			if (have_a0 == 1)
389				invalidate_entry(i);
390		}
391
392		pr_debug("   FID: 0x%x (%d.%dx [%dMHz])  "
393			 "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
394			 fid_codes[fid] % 10, speed_mhz, vid,
395			 mobile_vid_table[vid]/1000,
396			 mobile_vid_table[vid]%1000);
397
398		if (state->core_frequency != speed_mhz) {
399			state->core_frequency = speed_mhz;
400			pr_debug("   Corrected ACPI frequency to %d\n",
401				speed_mhz);
402		}
403
404		if (latency < pc.bits.sgtc)
405			latency = pc.bits.sgtc;
406
407		if (speed < minimum_speed)
408			minimum_speed = speed;
409		if (speed > maximum_speed)
410			maximum_speed = speed;
411	}
412
413	powernow_table[i].frequency = CPUFREQ_TABLE_END;
414	powernow_table[i].driver_data = 0;
415
416	/* notify BIOS that we exist */
417	acpi_processor_notify_smm(THIS_MODULE);
418
419	return 0;
420
421err2:
422	acpi_processor_unregister_performance(0);
423err1:
424	free_cpumask_var(acpi_processor_perf->shared_cpu_map);
425err05:
426	kfree(acpi_processor_perf);
427err0:
428	pr_warn("ACPI perflib can not be used on this platform\n");
429	acpi_processor_perf = NULL;
430	return retval;
431}
432#else
433static int powernow_acpi_init(void)
434{
435	pr_info("no support for ACPI processor found - please recompile your kernel with ACPI processor\n");
436	return -EINVAL;
437}
438#endif
439
440static void print_pst_entry(struct pst_s *pst, unsigned int j)
441{
442	pr_debug("PST:%d (@%p)\n", j, pst);
443	pr_debug(" cpuid: 0x%x  fsb: %d  maxFID: 0x%x  startvid: 0x%x\n",
444		pst->cpuid, pst->fsbspeed, pst->maxfid, pst->startvid);
445}
446
447static int powernow_decode_bios(int maxfid, int startvid)
448{
449	struct psb_s *psb;
450	struct pst_s *pst;
451	unsigned int i, j;
452	unsigned char *p;
453	unsigned int etuple;
454	unsigned int ret;
455
456	etuple = cpuid_eax(0x80000001);
457
458	for (i = 0xC0000; i < 0xffff0 ; i += 16) {
459
460		p = phys_to_virt(i);
461
462		if (memcmp(p, "AMDK7PNOW!",  10) == 0) {
463			pr_debug("Found PSB header at %p\n", p);
464			psb = (struct psb_s *) p;
465			pr_debug("Table version: 0x%x\n", psb->tableversion);
466			if (psb->tableversion != 0x12) {
467				pr_info("Sorry, only v1.2 tables supported right now\n");
468				return -ENODEV;
469			}
470
471			pr_debug("Flags: 0x%x\n", psb->flags);
472			if ((psb->flags & 1) == 0)
473				pr_debug("Mobile voltage regulator\n");
474			else
475				pr_debug("Desktop voltage regulator\n");
476
477			latency = psb->settlingtime;
478			if (latency < 100) {
479				pr_info("BIOS set settling time to %d microseconds. Should be at least 100. Correcting.\n",
480					latency);
481				latency = 100;
482			}
483			pr_debug("Settling Time: %d microseconds.\n",
484					psb->settlingtime);
485			pr_debug("Has %d PST tables. (Only dumping ones "
486					"relevant to this CPU).\n",
487					psb->numpst);
488
489			p += sizeof(*psb);
490
491			pst = (struct pst_s *) p;
492
493			for (j = 0; j < psb->numpst; j++) {
494				pst = (struct pst_s *) p;
495				number_scales = pst->numpstates;
496
497				if ((etuple == pst->cpuid) &&
498				    check_fsb(pst->fsbspeed) &&
499				    (maxfid == pst->maxfid) &&
500				    (startvid == pst->startvid)) {
501					print_pst_entry(pst, j);
502					p = (char *)pst + sizeof(*pst);
503					ret = get_ranges(p);
504					return ret;
505				} else {
506					unsigned int k;
507					p = (char *)pst + sizeof(*pst);
508					for (k = 0; k < number_scales; k++)
509						p += 2;
510				}
511			}
512			pr_info("No PST tables match this cpuid (0x%x)\n",
513				etuple);
514			pr_info("This is indicative of a broken BIOS\n");
515
516			return -EINVAL;
517		}
518		p++;
519	}
520
521	return -ENODEV;
522}
523
524
525/*
526 * We use the fact that the bus frequency is somehow
527 * a multiple of 100000/3 khz, then we compute sgtc according
528 * to this multiple.
529 * That way, we match more how AMD thinks all of that work.
530 * We will then get the same kind of behaviour already tested under
531 * the "well-known" other OS.
532 */
533static int fixup_sgtc(void)
534{
535	unsigned int sgtc;
536	unsigned int m;
537
538	m = fsb / 3333;
539	if ((m % 10) >= 5)
540		m += 5;
541
542	m /= 10;
543
544	sgtc = 100 * m * latency;
545	sgtc = sgtc / 3;
546	if (sgtc > 0xfffff) {
547		pr_warn("SGTC too large %d\n", sgtc);
548		sgtc = 0xfffff;
549	}
550	return sgtc;
551}
552
553static unsigned int powernow_get(unsigned int cpu)
554{
555	union msr_fidvidstatus fidvidstatus;
556	unsigned int cfid;
557
558	if (cpu)
559		return 0;
560	rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
561	cfid = fidvidstatus.bits.CFID;
562
563	return fsb * fid_codes[cfid] / 10;
564}
565
566
567static int acer_cpufreq_pst(const struct dmi_system_id *d)
568{
569	pr_warn("%s laptop with broken PST tables in BIOS detected\n",
570		d->ident);
571	pr_warn("You need to downgrade to 3A21 (09/09/2002), or try a newer BIOS than 3A71 (01/20/2003)\n");
572	pr_warn("cpufreq scaling has been disabled as a result of this\n");
573	return 0;
574}
575
576/*
577 * Some Athlon laptops have really fucked PST tables.
578 * A BIOS update is all that can save them.
579 * Mention this, and disable cpufreq.
580 */
581static const struct dmi_system_id powernow_dmi_table[] = {
582	{
583		.callback = acer_cpufreq_pst,
584		.ident = "Acer Aspire",
585		.matches = {
586			DMI_MATCH(DMI_SYS_VENDOR, "Insyde Software"),
587			DMI_MATCH(DMI_BIOS_VERSION, "3A71"),
588		},
589	},
590	{ }
591};
592
593static int powernow_cpu_init(struct cpufreq_policy *policy)
594{
595	union msr_fidvidstatus fidvidstatus;
596	int result;
597
598	if (policy->cpu != 0)
599		return -ENODEV;
600
601	rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
602
603	recalibrate_cpu_khz();
604
605	fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.CFID];
606	if (!fsb) {
607		pr_warn("can not determine bus frequency\n");
608		return -EINVAL;
609	}
610	pr_debug("FSB: %3dMHz\n", fsb/1000);
611
612	if (dmi_check_system(powernow_dmi_table) || acpi_force) {
613		pr_info("PSB/PST known to be broken - trying ACPI instead\n");
614		result = powernow_acpi_init();
615	} else {
616		result = powernow_decode_bios(fidvidstatus.bits.MFID,
617				fidvidstatus.bits.SVID);
618		if (result) {
619			pr_info("Trying ACPI perflib\n");
620			maximum_speed = 0;
621			minimum_speed = -1;
622			latency = 0;
623			result = powernow_acpi_init();
624			if (result) {
625				pr_info("ACPI and legacy methods failed\n");
626			}
627		} else {
628			/* SGTC use the bus clock as timer */
629			latency = fixup_sgtc();
630			pr_info("SGTC: %d\n", latency);
631		}
632	}
633
634	if (result)
635		return result;
636
637	pr_info("Minimum speed %d MHz - Maximum speed %d MHz\n",
638		minimum_speed/1000, maximum_speed/1000);
639
640	policy->cpuinfo.transition_latency =
641		cpufreq_scale(2000000UL, fsb, latency);
642	policy->freq_table = powernow_table;
643
644	return 0;
645}
646
647static int powernow_cpu_exit(struct cpufreq_policy *policy)
648{
649#ifdef CONFIG_X86_POWERNOW_K7_ACPI
650	if (acpi_processor_perf) {
651		acpi_processor_unregister_performance(0);
652		free_cpumask_var(acpi_processor_perf->shared_cpu_map);
653		kfree(acpi_processor_perf);
654	}
655#endif
656
657	kfree(powernow_table);
658	return 0;
659}
660
661static struct cpufreq_driver powernow_driver = {
662	.verify		= cpufreq_generic_frequency_table_verify,
663	.target_index	= powernow_target,
664	.get		= powernow_get,
665#ifdef CONFIG_X86_POWERNOW_K7_ACPI
666	.bios_limit	= acpi_processor_get_bios_limit,
667#endif
668	.init		= powernow_cpu_init,
669	.exit		= powernow_cpu_exit,
670	.name		= "powernow-k7",
671	.attr		= cpufreq_generic_attr,
672};
673
674static int __init powernow_init(void)
675{
676	if (check_powernow() == 0)
677		return -ENODEV;
678	return cpufreq_register_driver(&powernow_driver);
679}
680
681
682static void __exit powernow_exit(void)
683{
684	cpufreq_unregister_driver(&powernow_driver);
685}
686
687module_param(acpi_force,  int, 0444);
688MODULE_PARM_DESC(acpi_force, "Force ACPI to be used.");
689
690MODULE_AUTHOR("Dave Jones");
691MODULE_DESCRIPTION("Powernow driver for AMD K7 processors.");
692MODULE_LICENSE("GPL");
693
694late_initcall(powernow_init);
695module_exit(powernow_exit);
696
697