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
40 struct psb_s {
41 u8 signature[10];
42 u8 tableversion;
43 u8 flags;
44 u16 settlingtime;
45 u8 reserved1;
46 u8 numpst;
47 };
48
49 struct 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
58 union 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. */
70 static 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. */
78 static 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
89 static int acpi_force;
90
91 static struct cpufreq_frequency_table *powernow_table;
92
93 static unsigned int can_scale_bus;
94 static unsigned int can_scale_vid;
95 static unsigned int minimum_speed = -1;
96 static unsigned int maximum_speed;
97 static unsigned int number_scales;
98 static unsigned int fsb;
99 static unsigned int latency;
100 static char have_a0;
101
check_fsb(unsigned int fsbspeed)102 static 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
111 static const struct x86_cpu_id powernow_k7_cpuids[] = {
112 X86_MATCH_VENDOR_FAM(AMD, 6, NULL),
113 {}
114 };
115 MODULE_DEVICE_TABLE(x86cpu, powernow_k7_cpuids);
116
check_powernow(void)117 static 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
invalidate_entry(unsigned int entry)165 static void invalidate_entry(unsigned int entry)
166 {
167 powernow_table[entry].frequency = CPUFREQ_ENTRY_INVALID;
168 }
169 #endif
170
get_ranges(unsigned char * pst)171 static 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
change_FID(int fid)218 static 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
change_VID(int vid)233 static 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
powernow_target(struct cpufreq_policy * policy,unsigned int index)248 static 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
294 static struct acpi_processor_performance *acpi_processor_perf;
295
powernow_acpi_init(void)296 static 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
421 err2:
422 acpi_processor_unregister_performance(0);
423 err1:
424 free_cpumask_var(acpi_processor_perf->shared_cpu_map);
425 err05:
426 kfree(acpi_processor_perf);
427 err0:
428 pr_warn("ACPI perflib can not be used on this platform\n");
429 acpi_processor_perf = NULL;
430 return retval;
431 }
432 #else
powernow_acpi_init(void)433 static 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
print_pst_entry(struct pst_s * pst,unsigned int j)440 static 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
powernow_decode_bios(int maxfid,int startvid)447 static 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 */
fixup_sgtc(void)533 static 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
powernow_get(unsigned int cpu)553 static 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
acer_cpufreq_pst(const struct dmi_system_id * d)567 static 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 */
581 static 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
powernow_cpu_init(struct cpufreq_policy * policy)593 static 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
powernow_cpu_exit(struct cpufreq_policy * policy)647 static 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
661 static 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
powernow_init(void)674 static int __init powernow_init(void)
675 {
676 if (check_powernow() == 0)
677 return -ENODEV;
678 return cpufreq_register_driver(&powernow_driver);
679 }
680
681
powernow_exit(void)682 static void __exit powernow_exit(void)
683 {
684 cpufreq_unregister_driver(&powernow_driver);
685 }
686
687 module_param(acpi_force, int, 0444);
688 MODULE_PARM_DESC(acpi_force, "Force ACPI to be used.");
689
690 MODULE_AUTHOR("Dave Jones");
691 MODULE_DESCRIPTION("Powernow driver for AMD K7 processors.");
692 MODULE_LICENSE("GPL");
693
694 late_initcall(powernow_init);
695 module_exit(powernow_exit);
696
697