xref: /netbsd-src/sys/dev/acpi/acpi_cpu_tstate.c (revision 46f5119e40af2e51998f686b2fdcc76b5488f7f3)
1 /* $NetBSD: acpi_cpu_tstate.c,v 1.27 2011/03/19 12:57:31 jruoho Exp $ */
2 
3 /*-
4  * Copyright (c) 2010 Jukka Ruohonen <jruohonen@iki.fi>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: acpi_cpu_tstate.c,v 1.27 2011/03/19 12:57:31 jruoho Exp $");
31 
32 #include <sys/param.h>
33 #include <sys/kmem.h>
34 #include <sys/xcall.h>
35 
36 #include <dev/acpi/acpireg.h>
37 #include <dev/acpi/acpivar.h>
38 #include <dev/acpi/acpi_cpu.h>
39 
40 #define _COMPONENT	 ACPI_BUS_COMPONENT
41 ACPI_MODULE_NAME	 ("acpi_cpu_tstate")
42 
43 static ACPI_STATUS	 acpicpu_tstate_tss(struct acpicpu_softc *);
44 static ACPI_STATUS	 acpicpu_tstate_tss_add(struct acpicpu_tstate *,
45 						ACPI_OBJECT *);
46 static ACPI_STATUS	 acpicpu_tstate_ptc(struct acpicpu_softc *);
47 static ACPI_STATUS	 acpicpu_tstate_dep(struct acpicpu_softc *);
48 static ACPI_STATUS	 acpicpu_tstate_fadt(struct acpicpu_softc *);
49 static ACPI_STATUS	 acpicpu_tstate_change(struct acpicpu_softc *);
50 static void		 acpicpu_tstate_reset(struct acpicpu_softc *);
51 static void		 acpicpu_tstate_set_xcall(void *, void *);
52 
53 extern struct acpicpu_softc **acpicpu_sc;
54 
55 void
56 acpicpu_tstate_attach(device_t self)
57 {
58 	struct acpicpu_softc *sc = device_private(self);
59 	const char *str;
60 	ACPI_HANDLE tmp;
61 	ACPI_STATUS rv;
62 
63 	/*
64 	 * Disable T-states for PIIX4.
65 	 */
66 	if ((sc->sc_flags & ACPICPU_FLAG_PIIX4) != 0)
67 		return;
68 
69 	rv  = acpicpu_tstate_tss(sc);
70 
71 	if (ACPI_FAILURE(rv)) {
72 		str = "_TSS";
73 		goto out;
74 	}
75 
76 	rv = acpicpu_tstate_ptc(sc);
77 
78 	if (ACPI_FAILURE(rv)) {
79 		str = "_PTC";
80 		goto out;
81 	}
82 
83 	/*
84 	 * Query the optional _TSD.
85 	 */
86 	rv = acpicpu_tstate_dep(sc);
87 
88 	if (ACPI_SUCCESS(rv))
89 		sc->sc_flags |= ACPICPU_FLAG_T_DEP;
90 
91 	/*
92 	 * Comparable to P-states, the _TPC object may
93 	 * be absent in some systems, even though it is
94 	 * required by ACPI 3.0 along with _TSS and _PTC.
95 	 */
96 	rv = AcpiGetHandle(sc->sc_node->ad_handle, "_TPC", &tmp);
97 
98 	if (ACPI_FAILURE(rv)) {
99 		aprint_debug_dev(self, "_TPC missing\n");
100 		rv = AE_OK;
101 	}
102 
103 out:
104 	if (ACPI_FAILURE(rv)) {
105 
106 		if (rv != AE_NOT_FOUND)
107 			aprint_error_dev(sc->sc_dev, "failed to evaluate "
108 			    "%s: %s\n", str, AcpiFormatException(rv));
109 
110 		rv = acpicpu_tstate_fadt(sc);
111 
112 		if (ACPI_FAILURE(rv))
113 			return;
114 
115 		sc->sc_flags |= ACPICPU_FLAG_T_FADT;
116 	}
117 
118 	sc->sc_flags |= ACPICPU_FLAG_T;
119 
120 	acpicpu_tstate_reset(sc);
121 }
122 
123 int
124 acpicpu_tstate_detach(device_t self)
125 {
126 	struct acpicpu_softc *sc = device_private(self);
127 	size_t size;
128 
129 	if ((sc->sc_flags & ACPICPU_FLAG_T) == 0)
130 		return 0;
131 
132 	size = sc->sc_tstate_count * sizeof(*sc->sc_tstate);
133 
134 	if (sc->sc_tstate != NULL)
135 		kmem_free(sc->sc_tstate, size);
136 
137 	sc->sc_flags &= ~ACPICPU_FLAG_T;
138 
139 	return 0;
140 }
141 
142 void
143 acpicpu_tstate_start(device_t self)
144 {
145 	/* Nothing. */
146 }
147 
148 void
149 acpicpu_tstate_suspend(void *aux)
150 {
151 	struct acpicpu_softc *sc;
152 	device_t self = aux;
153 
154 	sc = device_private(self);
155 
156 	mutex_enter(&sc->sc_mtx);
157 	acpicpu_tstate_reset(sc);
158 	mutex_exit(&sc->sc_mtx);
159 }
160 
161 void
162 acpicpu_tstate_resume(void *aux)
163 {
164 	/* Nothing. */
165 }
166 
167 void
168 acpicpu_tstate_callback(void *aux)
169 {
170 	struct acpicpu_softc *sc;
171 	device_t self = aux;
172 	uint32_t omax, omin;
173 	int i;
174 
175 	sc = device_private(self);
176 
177 	if ((sc->sc_flags & ACPICPU_FLAG_T_FADT) != 0)
178 		return;
179 
180 	mutex_enter(&sc->sc_mtx);
181 
182 	/*
183 	 * If P-states are in use, we should ignore
184 	 * the interrupt unless we are in the highest
185 	 * P-state (see ACPI 4.0, section 8.4.3.3).
186 	 */
187 	if ((sc->sc_flags & ACPICPU_FLAG_P) != 0) {
188 
189 		for (i = sc->sc_pstate_count - 1; i >= 0; i--) {
190 
191 			if (sc->sc_pstate[i].ps_freq != 0)
192 				break;
193 		}
194 
195 		if (sc->sc_pstate_current != sc->sc_pstate[i].ps_freq) {
196 			mutex_exit(&sc->sc_mtx);
197 			return;
198 		}
199 	}
200 
201 	omax = sc->sc_tstate_max;
202 	omin = sc->sc_tstate_min;
203 
204 	(void)acpicpu_tstate_change(sc);
205 
206 	if (omax != sc->sc_tstate_max || omin != sc->sc_tstate_min) {
207 
208 		aprint_debug_dev(sc->sc_dev, "throttling window "
209 		    "changed from %u-%u %% to %u-%u %%\n",
210 		    sc->sc_tstate[omax].ts_percent,
211 		    sc->sc_tstate[omin].ts_percent,
212 		    sc->sc_tstate[sc->sc_tstate_max].ts_percent,
213 		    sc->sc_tstate[sc->sc_tstate_min].ts_percent);
214 	}
215 
216 	mutex_exit(&sc->sc_mtx);
217 }
218 
219 static ACPI_STATUS
220 acpicpu_tstate_tss(struct acpicpu_softc *sc)
221 {
222 	struct acpicpu_tstate *ts;
223 	ACPI_OBJECT *obj;
224 	ACPI_BUFFER buf;
225 	ACPI_STATUS rv;
226 	uint32_t count;
227 	uint32_t i, j;
228 
229 	rv = acpi_eval_struct(sc->sc_node->ad_handle, "_TSS", &buf);
230 
231 	if (ACPI_FAILURE(rv))
232 		return rv;
233 
234 	obj = buf.Pointer;
235 
236 	if (obj->Type != ACPI_TYPE_PACKAGE) {
237 		rv = AE_TYPE;
238 		goto out;
239 	}
240 
241 	sc->sc_tstate_count = obj->Package.Count;
242 
243 	if (sc->sc_tstate_count == 0) {
244 		rv = AE_NOT_EXIST;
245 		goto out;
246 	}
247 
248 	if (sc->sc_tstate_count > ACPICPU_T_STATE_MAX) {
249 		rv = AE_LIMIT;
250 		goto out;
251 	}
252 
253 	sc->sc_tstate = kmem_zalloc(sc->sc_tstate_count *
254 	    sizeof(struct acpicpu_tstate), KM_SLEEP);
255 
256 	if (sc->sc_tstate == NULL) {
257 		rv = AE_NO_MEMORY;
258 		goto out;
259 	}
260 
261 	for (count = i = 0; i < sc->sc_tstate_count; i++) {
262 
263 		ts = &sc->sc_tstate[i];
264 		rv = acpicpu_tstate_tss_add(ts, &obj->Package.Elements[i]);
265 
266 		if (ACPI_FAILURE(rv)) {
267 			ts->ts_percent = 0;
268 			continue;
269 		}
270 
271 		for (j = 0; j < i; j++) {
272 
273 			if (ts->ts_percent >= sc->sc_tstate[j].ts_percent) {
274 				ts->ts_percent = 0;
275 				break;
276 			}
277 		}
278 
279 		if (ts->ts_percent != 0)
280 			count++;
281 	}
282 
283 	if (count == 0) {
284 		rv = AE_NOT_EXIST;
285 		goto out;
286 	}
287 
288 	/*
289 	 * There must be an entry with the percent
290 	 * field of 100. If this is not true, and if
291 	 * this entry is not in the expected index,
292 	 * invalidate the use of T-states via _TSS.
293 	 */
294 	if (sc->sc_tstate[0].ts_percent != 100) {
295 		rv = AE_BAD_DECIMAL_CONSTANT;
296 		goto out;
297 	}
298 
299 out:
300 	if (buf.Pointer != NULL)
301 		ACPI_FREE(buf.Pointer);
302 
303 	return rv;
304 }
305 
306 static ACPI_STATUS
307 acpicpu_tstate_tss_add(struct acpicpu_tstate *ts, ACPI_OBJECT *obj)
308 {
309 	ACPI_OBJECT *elm;
310 	uint32_t val[5];
311 	uint32_t *p;
312 	int i;
313 
314 	if (obj->Type != ACPI_TYPE_PACKAGE)
315 		return AE_TYPE;
316 
317 	if (obj->Package.Count != 5)
318 		return AE_BAD_DATA;
319 
320 	elm = obj->Package.Elements;
321 
322 	for (i = 0; i < 5; i++) {
323 
324 		if (elm[i].Type != ACPI_TYPE_INTEGER)
325 			return AE_TYPE;
326 
327 		if (elm[i].Integer.Value > UINT32_MAX)
328 			return AE_AML_NUMERIC_OVERFLOW;
329 
330 		val[i] = elm[i].Integer.Value;
331 	}
332 
333 	p = &ts->ts_percent;
334 
335 	for (i = 0; i < 5; i++, p++)
336 		*p = val[i];
337 
338 	/*
339 	 * The minimum should be around 100 / 8 = 12.5 %.
340 	 */
341         if (ts->ts_percent < 10 || ts->ts_percent > 100)
342 		return AE_BAD_DECIMAL_CONSTANT;
343 
344 	if (ts->ts_latency == 0 || ts->ts_latency > 1000)
345 		ts->ts_latency = 1;
346 
347 	return AE_OK;
348 }
349 
350 ACPI_STATUS
351 acpicpu_tstate_ptc(struct acpicpu_softc *sc)
352 {
353 	static const size_t size = sizeof(struct acpicpu_reg);
354 	struct acpicpu_reg *reg[2];
355 	ACPI_OBJECT *elm, *obj;
356 	ACPI_BUFFER buf;
357 	ACPI_STATUS rv;
358 	int i;
359 
360 	rv = acpi_eval_struct(sc->sc_node->ad_handle, "_PTC", &buf);
361 
362 	if (ACPI_FAILURE(rv))
363 		return rv;
364 
365 	obj = buf.Pointer;
366 
367 	if (obj->Type != ACPI_TYPE_PACKAGE) {
368 		rv = AE_TYPE;
369 		goto out;
370 	}
371 
372 	if (obj->Package.Count != 2) {
373 		rv = AE_LIMIT;
374 		goto out;
375 	}
376 
377 	for (i = 0; i < 2; i++) {
378 
379 		elm = &obj->Package.Elements[i];
380 
381 		if (elm->Type != ACPI_TYPE_BUFFER) {
382 			rv = AE_TYPE;
383 			goto out;
384 		}
385 
386 		if (size > elm->Buffer.Length) {
387 			rv = AE_AML_BAD_RESOURCE_LENGTH;
388 			goto out;
389 		}
390 
391 		reg[i] = (struct acpicpu_reg *)elm->Buffer.Pointer;
392 
393 		switch (reg[i]->reg_spaceid) {
394 
395 		case ACPI_ADR_SPACE_SYSTEM_IO:
396 
397 			if (reg[i]->reg_addr == 0) {
398 				rv = AE_AML_ILLEGAL_ADDRESS;
399 				goto out;
400 			}
401 
402 			/*
403 			 * Check that the values match the IA32 clock
404 			 * modulation MSR, where the bit 0 is reserved,
405 			 * bits 1 through 3 define the duty cycle, and
406 			 * the fourth bit enables the modulation.
407 			 */
408 			if (reg[i]->reg_bitwidth != 4) {
409 				rv = AE_AML_BAD_RESOURCE_VALUE;
410 				goto out;
411 			}
412 
413 			if (reg[i]->reg_bitoffset != 1) {
414 				rv = AE_AML_BAD_RESOURCE_VALUE;
415 				goto out;
416 			}
417 
418 			break;
419 
420 		case ACPI_ADR_SPACE_FIXED_HARDWARE:
421 
422 			if ((sc->sc_flags & ACPICPU_FLAG_T_FFH) == 0) {
423 				rv = AE_SUPPORT;
424 				goto out;
425 			}
426 
427 			break;
428 
429 		default:
430 			rv = AE_AML_INVALID_SPACE_ID;
431 			goto out;
432 		}
433 	}
434 
435 	if (reg[0]->reg_spaceid != reg[1]->reg_spaceid) {
436 		rv = AE_AML_INVALID_SPACE_ID;
437 		goto out;
438 	}
439 
440 	(void)memcpy(&sc->sc_tstate_control, reg[0], size);
441 	(void)memcpy(&sc->sc_tstate_status,  reg[1], size);
442 
443 out:
444 	if (buf.Pointer != NULL)
445 		ACPI_FREE(buf.Pointer);
446 
447 	return rv;
448 }
449 
450 static ACPI_STATUS
451 acpicpu_tstate_dep(struct acpicpu_softc *sc)
452 {
453 	ACPI_OBJECT *elm, *obj;
454 	ACPI_BUFFER buf;
455 	ACPI_STATUS rv;
456 	uint32_t val;
457 	uint8_t i, n;
458 
459 	rv = acpi_eval_struct(sc->sc_node->ad_handle, "_TSD", &buf);
460 
461 	if (ACPI_FAILURE(rv))
462 		goto out;
463 
464 	obj = buf.Pointer;
465 
466 	if (obj->Type != ACPI_TYPE_PACKAGE) {
467 		rv = AE_TYPE;
468 		goto out;
469 	}
470 
471 	if (obj->Package.Count != 1) {
472 		rv = AE_LIMIT;
473 		goto out;
474 	}
475 
476 	elm = &obj->Package.Elements[0];
477 
478 	if (obj->Type != ACPI_TYPE_PACKAGE) {
479 		rv = AE_TYPE;
480 		goto out;
481 	}
482 
483 	n = elm->Package.Count;
484 
485 	if (n != 5) {
486 		rv = AE_LIMIT;
487 		goto out;
488 	}
489 
490 	elm = elm->Package.Elements;
491 
492 	for (i = 0; i < n; i++) {
493 
494 		if (elm[i].Type != ACPI_TYPE_INTEGER) {
495 			rv = AE_TYPE;
496 			goto out;
497 		}
498 
499 		if (elm[i].Integer.Value > UINT32_MAX) {
500 			rv = AE_AML_NUMERIC_OVERFLOW;
501 			goto out;
502 		}
503 	}
504 
505 	val = elm[1].Integer.Value;
506 
507 	if (val != 0)
508 		aprint_debug_dev(sc->sc_dev, "invalid revision in _TSD\n");
509 
510 	val = elm[3].Integer.Value;
511 
512 	if (val < ACPICPU_DEP_SW_ALL || val > ACPICPU_DEP_HW_ALL) {
513 		rv = AE_AML_BAD_RESOURCE_VALUE;
514 		goto out;
515 	}
516 
517 	val = elm[4].Integer.Value;
518 
519 	if (val > sc->sc_ncpus) {
520 		rv = AE_BAD_VALUE;
521 		goto out;
522 	}
523 
524 	sc->sc_tstate_dep.dep_domain = elm[2].Integer.Value;
525 	sc->sc_tstate_dep.dep_type   = elm[3].Integer.Value;
526 	sc->sc_tstate_dep.dep_ncpus  = elm[4].Integer.Value;
527 
528 out:
529 	if (ACPI_FAILURE(rv) && rv != AE_NOT_FOUND)
530 		aprint_debug_dev(sc->sc_dev, "failed to evaluate "
531 		    "_TSD: %s\n", AcpiFormatException(rv));
532 
533 	if (buf.Pointer != NULL)
534 		ACPI_FREE(buf.Pointer);
535 
536 	return rv;
537 }
538 
539 static ACPI_STATUS
540 acpicpu_tstate_fadt(struct acpicpu_softc *sc)
541 {
542 	static const size_t size = sizeof(struct acpicpu_tstate);
543 	const uint8_t offset = AcpiGbl_FADT.DutyOffset;
544 	const uint8_t width = AcpiGbl_FADT.DutyWidth;
545 	uint8_t beta, count, i;
546 
547 	if (sc->sc_object.ao_pblkaddr == 0)
548 		return AE_AML_ILLEGAL_ADDRESS;
549 
550 	/*
551 	 * A zero DUTY_WIDTH may be used announce
552 	 * that T-states are not available via FADT
553 	 * (ACPI 4.0, p. 121). See also (section 9.3):
554 	 *
555 	 *	Advanced Micro Devices: BIOS and Kernel
556 	 *	Developer's Guide for AMD Athlon 64 and
557 	 *	AMD Opteron Processors. Revision 3.30,
558 	 *	February 2006.
559 	 */
560 	if (width == 0 || width + offset > 4)
561 		return AE_AML_BAD_RESOURCE_VALUE;
562 
563 	count = 1 << width;
564 
565 	if (count > ACPICPU_T_STATE_MAX)
566 		return AE_LIMIT;
567 
568 	if (sc->sc_tstate != NULL)
569 		kmem_free(sc->sc_tstate, sc->sc_tstate_count * size);
570 
571 	sc->sc_tstate = kmem_zalloc(count * size, KM_SLEEP);
572 
573 	if (sc->sc_tstate == NULL)
574 		return ENOMEM;
575 
576 	sc->sc_tstate_count = count;
577 
578 	/*
579 	 * Approximate duty cycles and set the MSR values.
580 	 */
581 	for (beta = 100 / count, i = 0; i < count; i++) {
582 		sc->sc_tstate[i].ts_percent = 100 - beta * i;
583 		sc->sc_tstate[i].ts_latency = 1;
584 	}
585 
586 	for (i = 1; i < count; i++)
587 		sc->sc_tstate[i].ts_control = (count - i) | __BIT(3);
588 
589 	/*
590 	 * Fake values for throttling registers.
591 	 */
592 	(void)memset(&sc->sc_tstate_status, 0, sizeof(struct acpicpu_reg));
593 	(void)memset(&sc->sc_tstate_control, 0, sizeof(struct acpicpu_reg));
594 
595 	sc->sc_tstate_status.reg_bitwidth = width;
596 	sc->sc_tstate_status.reg_bitoffset = offset;
597 	sc->sc_tstate_status.reg_addr = sc->sc_object.ao_pblkaddr;
598 	sc->sc_tstate_status.reg_spaceid = ACPI_ADR_SPACE_SYSTEM_IO;
599 
600 	sc->sc_tstate_control.reg_bitwidth = width;
601 	sc->sc_tstate_control.reg_bitoffset = offset;
602 	sc->sc_tstate_control.reg_addr = sc->sc_object.ao_pblkaddr;
603 	sc->sc_tstate_control.reg_spaceid = ACPI_ADR_SPACE_SYSTEM_IO;
604 
605 	return AE_OK;
606 }
607 
608 static ACPI_STATUS
609 acpicpu_tstate_change(struct acpicpu_softc *sc)
610 {
611 	ACPI_INTEGER val;
612 	ACPI_STATUS rv;
613 
614 	acpicpu_tstate_reset(sc);
615 
616 	/*
617 	 * Evaluate the available T-state window:
618 	 *
619 	 *   _TPC : either this maximum or any lower power
620 	 *          (i.e. higher numbered) state may be used.
621 	 *
622 	 *   _TDL : either this minimum or any higher power
623 	 *	    (i.e. lower numbered) state may be used.
624 	 *
625 	 *   _TDL >= _TPC || _TDL >= _TSS[last entry].
626 	 */
627 	rv = acpi_eval_integer(sc->sc_node->ad_handle, "_TPC", &val);
628 
629 	if (ACPI_SUCCESS(rv) && val < sc->sc_tstate_count) {
630 
631 		if (sc->sc_tstate[val].ts_percent != 0)
632 			sc->sc_tstate_max = val;
633 	}
634 
635 	rv = acpi_eval_integer(sc->sc_node->ad_handle, "_TDL", &val);
636 
637 	if (ACPI_SUCCESS(rv) && val < sc->sc_tstate_count) {
638 
639 		if (val >= sc->sc_tstate_max &&
640 		    sc->sc_tstate[val].ts_percent != 0)
641 			sc->sc_tstate_min = val;
642 	}
643 
644 	return AE_OK;
645 }
646 
647 static void
648 acpicpu_tstate_reset(struct acpicpu_softc *sc)
649 {
650 
651 	sc->sc_tstate_max = 0;
652 	sc->sc_tstate_min = sc->sc_tstate_count - 1;
653 }
654 
655 int
656 acpicpu_tstate_get(struct cpu_info *ci, uint32_t *percent)
657 {
658 	struct acpicpu_tstate *ts = NULL;
659 	struct acpicpu_softc *sc;
660 	uint32_t i, val = 0;
661 	uint8_t offset;
662 	uint64_t addr;
663 	int rv;
664 
665 	sc = acpicpu_sc[ci->ci_acpiid];
666 
667 	if (__predict_false(sc == NULL)) {
668 		rv = ENXIO;
669 		goto fail;
670 	}
671 
672 	if (__predict_false(sc->sc_cold != false)) {
673 		rv = EBUSY;
674 		goto fail;
675 	}
676 
677 	if (__predict_false((sc->sc_flags & ACPICPU_FLAG_T) == 0)) {
678 		rv = ENODEV;
679 		goto fail;
680 	}
681 
682 	mutex_enter(&sc->sc_mtx);
683 
684 	if (sc->sc_tstate_current != ACPICPU_T_STATE_UNKNOWN) {
685 		*percent = sc->sc_tstate_current;
686 		mutex_exit(&sc->sc_mtx);
687 		return 0;
688 	}
689 
690 	mutex_exit(&sc->sc_mtx);
691 
692 	switch (sc->sc_tstate_status.reg_spaceid) {
693 
694 	case ACPI_ADR_SPACE_FIXED_HARDWARE:
695 
696 		rv = acpicpu_md_tstate_get(sc, percent);
697 
698 		if (__predict_false(rv != 0))
699 			goto fail;
700 
701 		break;
702 
703 	case ACPI_ADR_SPACE_SYSTEM_IO:
704 
705 		addr   = sc->sc_tstate_status.reg_addr;
706 		offset = sc->sc_tstate_status.reg_bitoffset;
707 
708 		(void)AcpiOsReadPort(addr, &val, 8);
709 
710 		val = (val >> offset) & 0x0F;
711 
712 		for (i = 0; i < sc->sc_tstate_count; i++) {
713 
714 			if (sc->sc_tstate[i].ts_percent == 0)
715 				continue;
716 
717 			if (val == sc->sc_tstate[i].ts_status) {
718 				ts = &sc->sc_tstate[i];
719 				break;
720 			}
721 		}
722 
723 		if (ts == NULL) {
724 			rv = EIO;
725 			goto fail;
726 		}
727 
728 		*percent = ts->ts_percent;
729 		break;
730 
731 	default:
732 		rv = ENOTTY;
733 		goto fail;
734 	}
735 
736 	mutex_enter(&sc->sc_mtx);
737 	sc->sc_tstate_current = *percent;
738 	mutex_exit(&sc->sc_mtx);
739 
740 	return 0;
741 
742 fail:
743 	aprint_error_dev(sc->sc_dev, "failed "
744 	    "to get T-state (err %d)\n", rv);
745 
746 	mutex_enter(&sc->sc_mtx);
747 	*percent = sc->sc_tstate_current = ACPICPU_T_STATE_UNKNOWN;
748 	mutex_exit(&sc->sc_mtx);
749 
750 	return rv;
751 }
752 
753 void
754 acpicpu_tstate_set(struct cpu_info *ci, uint32_t percent)
755 {
756 	uint64_t xc;
757 
758 	xc = xc_broadcast(0, acpicpu_tstate_set_xcall, &percent, NULL);
759 	xc_wait(xc);
760 }
761 
762 static void
763 acpicpu_tstate_set_xcall(void *arg1, void *arg2)
764 {
765 	struct acpicpu_tstate *ts = NULL;
766 	struct cpu_info *ci = curcpu();
767 	struct acpicpu_softc *sc;
768 	uint32_t i, percent, val;
769 	uint8_t offset;
770 	uint64_t addr;
771 	int rv;
772 
773 	percent = *(uint32_t *)arg1;
774 	sc = acpicpu_sc[ci->ci_acpiid];
775 
776 	if (__predict_false(sc == NULL)) {
777 		rv = ENXIO;
778 		goto fail;
779 	}
780 
781 	if (__predict_false(sc->sc_cold != false)) {
782 		rv = EBUSY;
783 		goto fail;
784 	}
785 
786 	if (__predict_false((sc->sc_flags & ACPICPU_FLAG_T) == 0)) {
787 		rv = ENODEV;
788 		goto fail;
789 	}
790 
791 	mutex_enter(&sc->sc_mtx);
792 
793 	if (sc->sc_tstate_current == percent) {
794 		mutex_exit(&sc->sc_mtx);
795 		return;
796 	}
797 
798 	for (i = sc->sc_tstate_max; i <= sc->sc_tstate_min; i++) {
799 
800 		if (__predict_false(sc->sc_tstate[i].ts_percent == 0))
801 			continue;
802 
803 		if (sc->sc_tstate[i].ts_percent == percent) {
804 			ts = &sc->sc_tstate[i];
805 			break;
806 		}
807 	}
808 
809 	mutex_exit(&sc->sc_mtx);
810 
811 	if (__predict_false(ts == NULL)) {
812 		rv = EINVAL;
813 		goto fail;
814 	}
815 
816 	switch (sc->sc_tstate_control.reg_spaceid) {
817 
818 	case ACPI_ADR_SPACE_FIXED_HARDWARE:
819 
820 		rv = acpicpu_md_tstate_set(ts);
821 
822 		if (__predict_false(rv != 0))
823 			goto fail;
824 
825 		break;
826 
827 	case ACPI_ADR_SPACE_SYSTEM_IO:
828 
829 		addr   = sc->sc_tstate_control.reg_addr;
830 		offset = sc->sc_tstate_control.reg_bitoffset;
831 
832 		val = (ts->ts_control & 0x0F) << offset;
833 
834 		if (ts->ts_percent != 100 && (val & __BIT(4)) == 0) {
835 			rv = EINVAL;
836 			goto fail;
837 		}
838 
839 		(void)AcpiOsWritePort(addr, val, 8);
840 
841 		/*
842 		 * If the status field is zero, the transition is
843 		 * specified to be "asynchronous" and there is no
844 		 * need to check the status (ACPI 4.0, 8.4.3.2).
845 		 */
846 		if (ts->ts_status == 0)
847 			break;
848 
849 		addr   = sc->sc_tstate_status.reg_addr;
850 		offset = sc->sc_tstate_status.reg_bitoffset;
851 
852 		for (i = val = 0; i < ACPICPU_T_STATE_RETRY; i++) {
853 
854 			(void)AcpiOsReadPort(addr, &val, 8);
855 
856 			val = (val >> offset) & 0x0F;
857 
858 			if (val == ts->ts_status)
859 				break;
860 
861 			DELAY(ts->ts_latency);
862 		}
863 
864 		if (i == ACPICPU_T_STATE_RETRY) {
865 			rv = EAGAIN;
866 			goto fail;
867 		}
868 
869 		break;
870 
871 	default:
872 		rv = ENOTTY;
873 		goto fail;
874 	}
875 
876 	mutex_enter(&sc->sc_mtx);
877 	ts->ts_evcnt.ev_count++;
878 	sc->sc_tstate_current = percent;
879 	mutex_exit(&sc->sc_mtx);
880 
881 	return;
882 
883 fail:
884 	aprint_error_dev(sc->sc_dev, "failed to "
885 	    "throttle to %u %% (err %d)\n", percent, rv);
886 
887 	mutex_enter(&sc->sc_mtx);
888 	sc->sc_tstate_current = ACPICPU_T_STATE_UNKNOWN;
889 	mutex_exit(&sc->sc_mtx);
890 }
891