xref: /freebsd/sys/kern/kern_cpu.c (revision 9bd497b8354567454e075076d40c996e21bd6095)
1 /*-
2  * Copyright (c) 2004-2007 Nate Lawson (SDG)
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/bus.h>
32 #include <sys/cpu.h>
33 #include <sys/eventhandler.h>
34 #include <sys/kernel.h>
35 #include <sys/lock.h>
36 #include <sys/malloc.h>
37 #include <sys/module.h>
38 #include <sys/proc.h>
39 #include <sys/queue.h>
40 #include <sys/sbuf.h>
41 #include <sys/sched.h>
42 #include <sys/smp.h>
43 #include <sys/sysctl.h>
44 #include <sys/systm.h>
45 #include <sys/sx.h>
46 #include <sys/timetc.h>
47 #include <sys/taskqueue.h>
48 
49 #include "cpufreq_if.h"
50 
51 /*
52  * Common CPU frequency glue code.  Drivers for specific hardware can
53  * attach this interface to allow users to get/set the CPU frequency.
54  */
55 
56 /*
57  * Number of levels we can handle.  Levels are synthesized from settings
58  * so for M settings and N drivers, there may be M*N levels.
59  */
60 #define CF_MAX_LEVELS	64
61 
62 struct cf_saved_freq {
63 	struct cf_level			level;
64 	int				priority;
65 	SLIST_ENTRY(cf_saved_freq)	link;
66 };
67 
68 struct cpufreq_softc {
69 	struct sx			lock;
70 	struct cf_level			curr_level;
71 	int				curr_priority;
72 	SLIST_HEAD(, cf_saved_freq)	saved_freq;
73 	struct cf_level_lst		all_levels;
74 	int				all_count;
75 	int				max_mhz;
76 	device_t			dev;
77 	struct sysctl_ctx_list		sysctl_ctx;
78 	struct task			startup_task;
79 };
80 
81 struct cf_setting_array {
82 	struct cf_setting		sets[MAX_SETTINGS];
83 	int				count;
84 	TAILQ_ENTRY(cf_setting_array)	link;
85 };
86 
87 TAILQ_HEAD(cf_setting_lst, cf_setting_array);
88 
89 #define CF_MTX_INIT(x)		sx_init((x), "cpufreq lock")
90 #define CF_MTX_LOCK(x)		sx_xlock((x))
91 #define CF_MTX_UNLOCK(x)	sx_xunlock((x))
92 #define CF_MTX_ASSERT(x)	sx_assert((x), SX_XLOCKED)
93 
94 #define CF_DEBUG(msg...)	do {		\
95 	if (cf_verbose)				\
96 		printf("cpufreq: " msg);	\
97 	} while (0)
98 
99 static int	cpufreq_attach(device_t dev);
100 static void	cpufreq_startup_task(void *ctx, int pending);
101 static int	cpufreq_detach(device_t dev);
102 static int	cf_set_method(device_t dev, const struct cf_level *level,
103 		    int priority);
104 static int	cf_get_method(device_t dev, struct cf_level *level);
105 static int	cf_levels_method(device_t dev, struct cf_level *levels,
106 		    int *count);
107 static int	cpufreq_insert_abs(struct cpufreq_softc *sc,
108 		    struct cf_setting *sets, int count);
109 static int	cpufreq_expand_set(struct cpufreq_softc *sc,
110 		    struct cf_setting_array *set_arr);
111 static struct cf_level *cpufreq_dup_set(struct cpufreq_softc *sc,
112 		    struct cf_level *dup, struct cf_setting *set);
113 static int	cpufreq_curr_sysctl(SYSCTL_HANDLER_ARGS);
114 static int	cpufreq_levels_sysctl(SYSCTL_HANDLER_ARGS);
115 static int	cpufreq_settings_sysctl(SYSCTL_HANDLER_ARGS);
116 
117 static device_method_t cpufreq_methods[] = {
118 	DEVMETHOD(device_probe,		bus_generic_probe),
119 	DEVMETHOD(device_attach,	cpufreq_attach),
120 	DEVMETHOD(device_detach,	cpufreq_detach),
121 
122         DEVMETHOD(cpufreq_set,		cf_set_method),
123         DEVMETHOD(cpufreq_get,		cf_get_method),
124         DEVMETHOD(cpufreq_levels,	cf_levels_method),
125 	{0, 0}
126 };
127 static driver_t cpufreq_driver = {
128 	"cpufreq", cpufreq_methods, sizeof(struct cpufreq_softc)
129 };
130 static devclass_t cpufreq_dc;
131 DRIVER_MODULE(cpufreq, cpu, cpufreq_driver, cpufreq_dc, 0, 0);
132 
133 static int		cf_lowest_freq;
134 static int		cf_verbose;
135 TUNABLE_INT("debug.cpufreq.lowest", &cf_lowest_freq);
136 TUNABLE_INT("debug.cpufreq.verbose", &cf_verbose);
137 SYSCTL_NODE(_debug, OID_AUTO, cpufreq, CTLFLAG_RD, NULL, "cpufreq debugging");
138 SYSCTL_INT(_debug_cpufreq, OID_AUTO, lowest, CTLFLAG_RW, &cf_lowest_freq, 1,
139     "Don't provide levels below this frequency.");
140 SYSCTL_INT(_debug_cpufreq, OID_AUTO, verbose, CTLFLAG_RW, &cf_verbose, 1,
141     "Print verbose debugging messages");
142 
143 static int
144 cpufreq_attach(device_t dev)
145 {
146 	struct cpufreq_softc *sc;
147 	struct pcpu *pc;
148 	device_t parent;
149 	uint64_t rate;
150 	int numdevs;
151 
152 	CF_DEBUG("initializing %s\n", device_get_nameunit(dev));
153 	sc = device_get_softc(dev);
154 	parent = device_get_parent(dev);
155 	sc->dev = dev;
156 	sysctl_ctx_init(&sc->sysctl_ctx);
157 	TAILQ_INIT(&sc->all_levels);
158 	CF_MTX_INIT(&sc->lock);
159 	sc->curr_level.total_set.freq = CPUFREQ_VAL_UNKNOWN;
160 	SLIST_INIT(&sc->saved_freq);
161 	/* Try to get nominal CPU freq to use it as maximum later if needed */
162 	sc->max_mhz = cpu_get_nominal_mhz(dev);
163 	/* If that fails, try to measure the current rate */
164 	if (sc->max_mhz <= 0) {
165 		pc = cpu_get_pcpu(dev);
166 		if (cpu_est_clockrate(pc->pc_cpuid, &rate) == 0)
167 			sc->max_mhz = rate / 1000000;
168 		else
169 			sc->max_mhz = CPUFREQ_VAL_UNKNOWN;
170 	}
171 
172 	/*
173 	 * Only initialize one set of sysctls for all CPUs.  In the future,
174 	 * if multiple CPUs can have different settings, we can move these
175 	 * sysctls to be under every CPU instead of just the first one.
176 	 */
177 	numdevs = devclass_get_count(cpufreq_dc);
178 	if (numdevs > 1)
179 		return (0);
180 
181 	CF_DEBUG("initializing one-time data for %s\n",
182 	    device_get_nameunit(dev));
183 	SYSCTL_ADD_PROC(&sc->sysctl_ctx,
184 	    SYSCTL_CHILDREN(device_get_sysctl_tree(parent)),
185 	    OID_AUTO, "freq", CTLTYPE_INT | CTLFLAG_RW, sc, 0,
186 	    cpufreq_curr_sysctl, "I", "Current CPU frequency");
187 	SYSCTL_ADD_PROC(&sc->sysctl_ctx,
188 	    SYSCTL_CHILDREN(device_get_sysctl_tree(parent)),
189 	    OID_AUTO, "freq_levels", CTLTYPE_STRING | CTLFLAG_RD, sc, 0,
190 	    cpufreq_levels_sysctl, "A", "CPU frequency levels");
191 
192 	/*
193 	 * Queue a one-shot broadcast that levels have changed.
194 	 * It will run once the system has completed booting.
195 	 */
196 	TASK_INIT(&sc->startup_task, 0, cpufreq_startup_task, dev);
197 	taskqueue_enqueue(taskqueue_thread, &sc->startup_task);
198 
199 	return (0);
200 }
201 
202 /* Handle any work to be done for all drivers that attached during boot. */
203 static void
204 cpufreq_startup_task(void *ctx, int pending)
205 {
206 
207 	cpufreq_settings_changed((device_t)ctx);
208 }
209 
210 static int
211 cpufreq_detach(device_t dev)
212 {
213 	struct cpufreq_softc *sc;
214 	struct cf_saved_freq *saved_freq;
215 	int numdevs;
216 
217 	CF_DEBUG("shutdown %s\n", device_get_nameunit(dev));
218 	sc = device_get_softc(dev);
219 	sysctl_ctx_free(&sc->sysctl_ctx);
220 
221 	while ((saved_freq = SLIST_FIRST(&sc->saved_freq)) != NULL) {
222 		SLIST_REMOVE_HEAD(&sc->saved_freq, link);
223 		free(saved_freq, M_TEMP);
224 	}
225 
226 	/* Only clean up these resources when the last device is detaching. */
227 	numdevs = devclass_get_count(cpufreq_dc);
228 	if (numdevs == 1) {
229 		CF_DEBUG("final shutdown for %s\n", device_get_nameunit(dev));
230 	}
231 
232 	return (0);
233 }
234 
235 static int
236 cf_set_method(device_t dev, const struct cf_level *level, int priority)
237 {
238 	struct cpufreq_softc *sc;
239 	const struct cf_setting *set;
240 	struct cf_saved_freq *saved_freq, *curr_freq;
241 	struct pcpu *pc;
242 	int error, i;
243 
244 	sc = device_get_softc(dev);
245 	error = 0;
246 	set = NULL;
247 	saved_freq = NULL;
248 
249 	/* We are going to change levels so notify the pre-change handler. */
250 	EVENTHANDLER_INVOKE(cpufreq_pre_change, level, &error);
251 	if (error != 0) {
252 		EVENTHANDLER_INVOKE(cpufreq_post_change, level, error);
253 		return (error);
254 	}
255 
256 	CF_MTX_LOCK(&sc->lock);
257 
258 #ifdef SMP
259 	/*
260 	 * If still booting and secondary CPUs not started yet, don't allow
261 	 * changing the frequency until they're online.  This is because we
262 	 * can't switch to them using sched_bind() and thus we'd only be
263 	 * switching the main CPU.  XXXTODO: Need to think more about how to
264 	 * handle having different CPUs at different frequencies.
265 	 */
266 	if (mp_ncpus > 1 && !smp_active) {
267 		device_printf(dev, "rejecting change, SMP not started yet\n");
268 		error = ENXIO;
269 		goto out;
270 	}
271 #endif /* SMP */
272 
273 	/*
274 	 * If the requested level has a lower priority, don't allow
275 	 * the new level right now.
276 	 */
277 	if (priority < sc->curr_priority) {
278 		CF_DEBUG("ignoring, curr prio %d less than %d\n", priority,
279 		    sc->curr_priority);
280 		error = EPERM;
281 		goto out;
282 	}
283 
284 	/*
285 	 * If the caller didn't specify a level and one is saved, prepare to
286 	 * restore the saved level.  If none has been saved, return an error.
287 	 */
288 	if (level == NULL) {
289 		saved_freq = SLIST_FIRST(&sc->saved_freq);
290 		if (saved_freq == NULL) {
291 			CF_DEBUG("NULL level, no saved level\n");
292 			error = ENXIO;
293 			goto out;
294 		}
295 		level = &saved_freq->level;
296 		priority = saved_freq->priority;
297 		CF_DEBUG("restoring saved level, freq %d prio %d\n",
298 		    level->total_set.freq, priority);
299 	}
300 
301 	/* Reject levels that are below our specified threshold. */
302 	if (level->total_set.freq < cf_lowest_freq) {
303 		CF_DEBUG("rejecting freq %d, less than %d limit\n",
304 		    level->total_set.freq, cf_lowest_freq);
305 		error = EINVAL;
306 		goto out;
307 	}
308 
309 	/* If already at this level, just return. */
310 	if (CPUFREQ_CMP(sc->curr_level.total_set.freq, level->total_set.freq)) {
311 		CF_DEBUG("skipping freq %d, same as current level %d\n",
312 		    level->total_set.freq, sc->curr_level.total_set.freq);
313 		goto skip;
314 	}
315 
316 	/* First, set the absolute frequency via its driver. */
317 	set = &level->abs_set;
318 	if (set->dev) {
319 		if (!device_is_attached(set->dev)) {
320 			error = ENXIO;
321 			goto out;
322 		}
323 
324 		/* Bind to the target CPU before switching. */
325 		pc = cpu_get_pcpu(set->dev);
326 		thread_lock(curthread);
327 		sched_bind(curthread, pc->pc_cpuid);
328 		thread_unlock(curthread);
329 		CF_DEBUG("setting abs freq %d on %s (cpu %d)\n", set->freq,
330 		    device_get_nameunit(set->dev), PCPU_GET(cpuid));
331 		error = CPUFREQ_DRV_SET(set->dev, set);
332 		thread_lock(curthread);
333 		sched_unbind(curthread);
334 		thread_unlock(curthread);
335 		if (error) {
336 			goto out;
337 		}
338 	}
339 
340 	/* Next, set any/all relative frequencies via their drivers. */
341 	for (i = 0; i < level->rel_count; i++) {
342 		set = &level->rel_set[i];
343 		if (!device_is_attached(set->dev)) {
344 			error = ENXIO;
345 			goto out;
346 		}
347 
348 		/* Bind to the target CPU before switching. */
349 		pc = cpu_get_pcpu(set->dev);
350 		thread_lock(curthread);
351 		sched_bind(curthread, pc->pc_cpuid);
352 		thread_unlock(curthread);
353 		CF_DEBUG("setting rel freq %d on %s (cpu %d)\n", set->freq,
354 		    device_get_nameunit(set->dev), PCPU_GET(cpuid));
355 		error = CPUFREQ_DRV_SET(set->dev, set);
356 		thread_lock(curthread);
357 		sched_unbind(curthread);
358 		thread_unlock(curthread);
359 		if (error) {
360 			/* XXX Back out any successful setting? */
361 			goto out;
362 		}
363 	}
364 
365 skip:
366 	/*
367 	 * Before recording the current level, check if we're going to a
368 	 * higher priority.  If so, save the previous level and priority.
369 	 */
370 	if (sc->curr_level.total_set.freq != CPUFREQ_VAL_UNKNOWN &&
371 	    priority > sc->curr_priority) {
372 		CF_DEBUG("saving level, freq %d prio %d\n",
373 		    sc->curr_level.total_set.freq, sc->curr_priority);
374 		curr_freq = malloc(sizeof(*curr_freq), M_TEMP, M_NOWAIT);
375 		if (curr_freq == NULL) {
376 			error = ENOMEM;
377 			goto out;
378 		}
379 		curr_freq->level = sc->curr_level;
380 		curr_freq->priority = sc->curr_priority;
381 		SLIST_INSERT_HEAD(&sc->saved_freq, curr_freq, link);
382 	}
383 	sc->curr_level = *level;
384 	sc->curr_priority = priority;
385 
386 	/* If we were restoring a saved state, reset it to "unused". */
387 	if (saved_freq != NULL) {
388 		CF_DEBUG("resetting saved level\n");
389 		sc->curr_level.total_set.freq = CPUFREQ_VAL_UNKNOWN;
390 		SLIST_REMOVE_HEAD(&sc->saved_freq, link);
391 		free(saved_freq, M_TEMP);
392 	}
393 
394 out:
395 	CF_MTX_UNLOCK(&sc->lock);
396 
397 	/*
398 	 * We changed levels (or attempted to) so notify the post-change
399 	 * handler of new frequency or error.
400 	 */
401 	EVENTHANDLER_INVOKE(cpufreq_post_change, level, error);
402 	if (error && set)
403 		device_printf(set->dev, "set freq failed, err %d\n", error);
404 
405 	return (error);
406 }
407 
408 static int
409 cf_get_method(device_t dev, struct cf_level *level)
410 {
411 	struct cpufreq_softc *sc;
412 	struct cf_level *levels;
413 	struct cf_setting *curr_set, set;
414 	struct pcpu *pc;
415 	device_t *devs;
416 	int count, error, i, n, numdevs;
417 	uint64_t rate;
418 
419 	sc = device_get_softc(dev);
420 	error = 0;
421 	levels = NULL;
422 
423 	/* If we already know the current frequency, we're done. */
424 	CF_MTX_LOCK(&sc->lock);
425 	curr_set = &sc->curr_level.total_set;
426 	if (curr_set->freq != CPUFREQ_VAL_UNKNOWN) {
427 		CF_DEBUG("get returning known freq %d\n", curr_set->freq);
428 		goto out;
429 	}
430 	CF_MTX_UNLOCK(&sc->lock);
431 
432 	/*
433 	 * We need to figure out the current level.  Loop through every
434 	 * driver, getting the current setting.  Then, attempt to get a best
435 	 * match of settings against each level.
436 	 */
437 	count = CF_MAX_LEVELS;
438 	levels = malloc(count * sizeof(*levels), M_TEMP, M_NOWAIT);
439 	if (levels == NULL)
440 		return (ENOMEM);
441 	error = CPUFREQ_LEVELS(sc->dev, levels, &count);
442 	if (error) {
443 		if (error == E2BIG)
444 			printf("cpufreq: need to increase CF_MAX_LEVELS\n");
445 		free(levels, M_TEMP);
446 		return (error);
447 	}
448 	error = device_get_children(device_get_parent(dev), &devs, &numdevs);
449 	if (error) {
450 		free(levels, M_TEMP);
451 		return (error);
452 	}
453 
454 	/*
455 	 * Reacquire the lock and search for the given level.
456 	 *
457 	 * XXX Note: this is not quite right since we really need to go
458 	 * through each level and compare both absolute and relative
459 	 * settings for each driver in the system before making a match.
460 	 * The estimation code below catches this case though.
461 	 */
462 	CF_MTX_LOCK(&sc->lock);
463 	for (n = 0; n < numdevs && curr_set->freq == CPUFREQ_VAL_UNKNOWN; n++) {
464 		if (!device_is_attached(devs[n]))
465 			continue;
466 		if (CPUFREQ_DRV_GET(devs[n], &set) != 0)
467 			continue;
468 		for (i = 0; i < count; i++) {
469 			if (CPUFREQ_CMP(set.freq, levels[i].total_set.freq)) {
470 				sc->curr_level = levels[i];
471 				break;
472 			}
473 		}
474 	}
475 	free(devs, M_TEMP);
476 	if (curr_set->freq != CPUFREQ_VAL_UNKNOWN) {
477 		CF_DEBUG("get matched freq %d from drivers\n", curr_set->freq);
478 		goto out;
479 	}
480 
481 	/*
482 	 * We couldn't find an exact match, so attempt to estimate and then
483 	 * match against a level.
484 	 */
485 	pc = cpu_get_pcpu(dev);
486 	if (pc == NULL) {
487 		error = ENXIO;
488 		goto out;
489 	}
490 	cpu_est_clockrate(pc->pc_cpuid, &rate);
491 	rate /= 1000000;
492 	for (i = 0; i < count; i++) {
493 		if (CPUFREQ_CMP(rate, levels[i].total_set.freq)) {
494 			sc->curr_level = levels[i];
495 			CF_DEBUG("get estimated freq %d\n", curr_set->freq);
496 			goto out;
497 		}
498 	}
499 	error = ENXIO;
500 
501 out:
502 	if (error == 0)
503 		*level = sc->curr_level;
504 
505 	CF_MTX_UNLOCK(&sc->lock);
506 	if (levels)
507 		free(levels, M_TEMP);
508 	return (error);
509 }
510 
511 static int
512 cf_levels_method(device_t dev, struct cf_level *levels, int *count)
513 {
514 	struct cf_setting_array *set_arr;
515 	struct cf_setting_lst rel_sets;
516 	struct cpufreq_softc *sc;
517 	struct cf_level *lev;
518 	struct cf_setting *sets;
519 	struct pcpu *pc;
520 	device_t *devs;
521 	int error, i, numdevs, set_count, type;
522 	uint64_t rate;
523 
524 	if (levels == NULL || count == NULL)
525 		return (EINVAL);
526 
527 	TAILQ_INIT(&rel_sets);
528 	sc = device_get_softc(dev);
529 	error = device_get_children(device_get_parent(dev), &devs, &numdevs);
530 	if (error)
531 		return (error);
532 	sets = malloc(MAX_SETTINGS * sizeof(*sets), M_TEMP, M_NOWAIT);
533 	if (sets == NULL) {
534 		free(devs, M_TEMP);
535 		return (ENOMEM);
536 	}
537 
538 	/* Get settings from all cpufreq drivers. */
539 	CF_MTX_LOCK(&sc->lock);
540 	for (i = 0; i < numdevs; i++) {
541 		/* Skip devices that aren't ready. */
542 		if (!device_is_attached(devs[i]))
543 			continue;
544 
545 		/*
546 		 * Get settings, skipping drivers that offer no settings or
547 		 * provide settings for informational purposes only.
548 		 */
549 		error = CPUFREQ_DRV_TYPE(devs[i], &type);
550 		if (error || (type & CPUFREQ_FLAG_INFO_ONLY)) {
551 			if (error == 0) {
552 				CF_DEBUG("skipping info-only driver %s\n",
553 				    device_get_nameunit(devs[i]));
554 			}
555 			continue;
556 		}
557 		set_count = MAX_SETTINGS;
558 		error = CPUFREQ_DRV_SETTINGS(devs[i], sets, &set_count);
559 		if (error || set_count == 0)
560 			continue;
561 
562 		/* Add the settings to our absolute/relative lists. */
563 		switch (type & CPUFREQ_TYPE_MASK) {
564 		case CPUFREQ_TYPE_ABSOLUTE:
565 			error = cpufreq_insert_abs(sc, sets, set_count);
566 			break;
567 		case CPUFREQ_TYPE_RELATIVE:
568 			CF_DEBUG("adding %d relative settings\n", set_count);
569 			set_arr = malloc(sizeof(*set_arr), M_TEMP, M_NOWAIT);
570 			if (set_arr == NULL) {
571 				error = ENOMEM;
572 				goto out;
573 			}
574 			bcopy(sets, set_arr->sets, set_count * sizeof(*sets));
575 			set_arr->count = set_count;
576 			TAILQ_INSERT_TAIL(&rel_sets, set_arr, link);
577 			break;
578 		default:
579 			error = EINVAL;
580 		}
581 		if (error)
582 			goto out;
583 	}
584 
585 	/*
586 	 * If there are no absolute levels, create a fake one at 100%.  We
587 	 * then cache the clockrate for later use as our base frequency.
588 	 */
589 	if (TAILQ_EMPTY(&sc->all_levels)) {
590 		if (sc->max_mhz == CPUFREQ_VAL_UNKNOWN) {
591 			sc->max_mhz = cpu_get_nominal_mhz(dev);
592 			/*
593 			 * If the CPU can't report a rate for 100%, hope
594 			 * the CPU is running at its nominal rate right now,
595 			 * and use that instead.
596 			 */
597 			if (sc->max_mhz <= 0) {
598 				pc = cpu_get_pcpu(dev);
599 				cpu_est_clockrate(pc->pc_cpuid, &rate);
600 				sc->max_mhz = rate / 1000000;
601 			}
602 		}
603 		memset(&sets[0], CPUFREQ_VAL_UNKNOWN, sizeof(*sets));
604 		sets[0].freq = sc->max_mhz;
605 		sets[0].dev = NULL;
606 		error = cpufreq_insert_abs(sc, sets, 1);
607 		if (error)
608 			goto out;
609 	}
610 
611 	/* Create a combined list of absolute + relative levels. */
612 	TAILQ_FOREACH(set_arr, &rel_sets, link)
613 		cpufreq_expand_set(sc, set_arr);
614 
615 	/* If the caller doesn't have enough space, return the actual count. */
616 	if (sc->all_count > *count) {
617 		*count = sc->all_count;
618 		error = E2BIG;
619 		goto out;
620 	}
621 
622 	/* Finally, output the list of levels. */
623 	i = 0;
624 	TAILQ_FOREACH(lev, &sc->all_levels, link) {
625 		/*
626 		 * Skip levels that are too close in frequency to the
627 		 * previous levels.  Some systems report bogus duplicate
628 		 * settings (i.e., for acpi_perf).
629 		 */
630 		if (i > 0 && CPUFREQ_CMP(lev->total_set.freq,
631 		    levels[i - 1].total_set.freq)) {
632 			sc->all_count--;
633 			continue;
634 		}
635 
636 		/* Skip levels that have a frequency that is too low. */
637 		if (lev->total_set.freq < cf_lowest_freq) {
638 			sc->all_count--;
639 			continue;
640 		}
641 
642 		levels[i] = *lev;
643 		i++;
644 	}
645 	*count = sc->all_count;
646 	error = 0;
647 
648 out:
649 	/* Clear all levels since we regenerate them each time. */
650 	while ((lev = TAILQ_FIRST(&sc->all_levels)) != NULL) {
651 		TAILQ_REMOVE(&sc->all_levels, lev, link);
652 		free(lev, M_TEMP);
653 	}
654 	sc->all_count = 0;
655 
656 	CF_MTX_UNLOCK(&sc->lock);
657 	while ((set_arr = TAILQ_FIRST(&rel_sets)) != NULL) {
658 		TAILQ_REMOVE(&rel_sets, set_arr, link);
659 		free(set_arr, M_TEMP);
660 	}
661 	free(devs, M_TEMP);
662 	free(sets, M_TEMP);
663 	return (error);
664 }
665 
666 /*
667  * Create levels for an array of absolute settings and insert them in
668  * sorted order in the specified list.
669  */
670 static int
671 cpufreq_insert_abs(struct cpufreq_softc *sc, struct cf_setting *sets,
672     int count)
673 {
674 	struct cf_level_lst *list;
675 	struct cf_level *level, *search;
676 	int i;
677 
678 	CF_MTX_ASSERT(&sc->lock);
679 
680 	list = &sc->all_levels;
681 	for (i = 0; i < count; i++) {
682 		level = malloc(sizeof(*level), M_TEMP, M_NOWAIT | M_ZERO);
683 		if (level == NULL)
684 			return (ENOMEM);
685 		level->abs_set = sets[i];
686 		level->total_set = sets[i];
687 		level->total_set.dev = NULL;
688 		sc->all_count++;
689 
690 		if (TAILQ_EMPTY(list)) {
691 			CF_DEBUG("adding abs setting %d at head\n",
692 			    sets[i].freq);
693 			TAILQ_INSERT_HEAD(list, level, link);
694 			continue;
695 		}
696 
697 		TAILQ_FOREACH_REVERSE(search, list, cf_level_lst, link) {
698 			if (sets[i].freq <= search->total_set.freq) {
699 				CF_DEBUG("adding abs setting %d after %d\n",
700 				    sets[i].freq, search->total_set.freq);
701 				TAILQ_INSERT_AFTER(list, search, level, link);
702 				break;
703 			}
704 		}
705 	}
706 	return (0);
707 }
708 
709 /*
710  * Expand a group of relative settings, creating derived levels from them.
711  */
712 static int
713 cpufreq_expand_set(struct cpufreq_softc *sc, struct cf_setting_array *set_arr)
714 {
715 	struct cf_level *fill, *search;
716 	struct cf_setting *set;
717 	int i;
718 
719 	CF_MTX_ASSERT(&sc->lock);
720 
721 	/*
722 	 * Walk the set of all existing levels in reverse.  This is so we
723 	 * create derived states from the lowest absolute settings first
724 	 * and discard duplicates created from higher absolute settings.
725 	 * For instance, a level of 50 Mhz derived from 100 Mhz + 50% is
726 	 * preferable to 200 Mhz + 25% because absolute settings are more
727 	 * efficient since they often change the voltage as well.
728 	 */
729 	TAILQ_FOREACH_REVERSE(search, &sc->all_levels, cf_level_lst, link) {
730 		/* Add each setting to the level, duplicating if necessary. */
731 		for (i = 0; i < set_arr->count; i++) {
732 			set = &set_arr->sets[i];
733 
734 			/*
735 			 * If this setting is less than 100%, split the level
736 			 * into two and add this setting to the new level.
737 			 */
738 			fill = search;
739 			if (set->freq < 10000) {
740 				fill = cpufreq_dup_set(sc, search, set);
741 
742 				/*
743 				 * The new level was a duplicate of an existing
744 				 * level or its absolute setting is too high
745 				 * so we freed it.  For example, we discard a
746 				 * derived level of 1000 MHz/25% if a level
747 				 * of 500 MHz/100% already exists.
748 				 */
749 				if (fill == NULL)
750 					break;
751 			}
752 
753 			/* Add this setting to the existing or new level. */
754 			KASSERT(fill->rel_count < MAX_SETTINGS,
755 			    ("cpufreq: too many relative drivers (%d)",
756 			    MAX_SETTINGS));
757 			fill->rel_set[fill->rel_count] = *set;
758 			fill->rel_count++;
759 			CF_DEBUG(
760 			"expand set added rel setting %d%% to %d level\n",
761 			    set->freq / 100, fill->total_set.freq);
762 		}
763 	}
764 
765 	return (0);
766 }
767 
768 static struct cf_level *
769 cpufreq_dup_set(struct cpufreq_softc *sc, struct cf_level *dup,
770     struct cf_setting *set)
771 {
772 	struct cf_level_lst *list;
773 	struct cf_level *fill, *itr;
774 	struct cf_setting *fill_set, *itr_set;
775 	int i;
776 
777 	CF_MTX_ASSERT(&sc->lock);
778 
779 	/*
780 	 * Create a new level, copy it from the old one, and update the
781 	 * total frequency and power by the percentage specified in the
782 	 * relative setting.
783 	 */
784 	fill = malloc(sizeof(*fill), M_TEMP, M_NOWAIT);
785 	if (fill == NULL)
786 		return (NULL);
787 	*fill = *dup;
788 	fill_set = &fill->total_set;
789 	fill_set->freq =
790 	    ((uint64_t)fill_set->freq * set->freq) / 10000;
791 	if (fill_set->power != CPUFREQ_VAL_UNKNOWN) {
792 		fill_set->power = ((uint64_t)fill_set->power * set->freq)
793 		    / 10000;
794 	}
795 	if (set->lat != CPUFREQ_VAL_UNKNOWN) {
796 		if (fill_set->lat != CPUFREQ_VAL_UNKNOWN)
797 			fill_set->lat += set->lat;
798 		else
799 			fill_set->lat = set->lat;
800 	}
801 	CF_DEBUG("dup set considering derived setting %d\n", fill_set->freq);
802 
803 	/*
804 	 * If we copied an old level that we already modified (say, at 100%),
805 	 * we need to remove that setting before adding this one.  Since we
806 	 * process each setting array in order, we know any settings for this
807 	 * driver will be found at the end.
808 	 */
809 	for (i = fill->rel_count; i != 0; i--) {
810 		if (fill->rel_set[i - 1].dev != set->dev)
811 			break;
812 		CF_DEBUG("removed last relative driver: %s\n",
813 		    device_get_nameunit(set->dev));
814 		fill->rel_count--;
815 	}
816 
817 	/*
818 	 * Insert the new level in sorted order.  If it is a duplicate of an
819 	 * existing level (1) or has an absolute setting higher than the
820 	 * existing level (2), do not add it.  We can do this since any such
821 	 * level is guaranteed use less power.  For example (1), a level with
822 	 * one absolute setting of 800 Mhz uses less power than one composed
823 	 * of an absolute setting of 1600 Mhz and a relative setting at 50%.
824 	 * Also for example (2), a level of 800 Mhz/75% is preferable to
825 	 * 1600 Mhz/25% even though the latter has a lower total frequency.
826 	 */
827 	list = &sc->all_levels;
828 	KASSERT(!TAILQ_EMPTY(list), ("all levels list empty in dup set"));
829 	TAILQ_FOREACH_REVERSE(itr, list, cf_level_lst, link) {
830 		itr_set = &itr->total_set;
831 		if (CPUFREQ_CMP(fill_set->freq, itr_set->freq)) {
832 			CF_DEBUG("dup set rejecting %d (dupe)\n",
833 			    fill_set->freq);
834 			itr = NULL;
835 			break;
836 		} else if (fill_set->freq < itr_set->freq) {
837 			if (fill->abs_set.freq <= itr->abs_set.freq) {
838 				CF_DEBUG(
839 			"dup done, inserting new level %d after %d\n",
840 				    fill_set->freq, itr_set->freq);
841 				TAILQ_INSERT_AFTER(list, itr, fill, link);
842 				sc->all_count++;
843 			} else {
844 				CF_DEBUG("dup set rejecting %d (abs too big)\n",
845 				    fill_set->freq);
846 				itr = NULL;
847 			}
848 			break;
849 		}
850 	}
851 
852 	/* We didn't find a good place for this new level so free it. */
853 	if (itr == NULL) {
854 		CF_DEBUG("dup set freeing new level %d (not optimal)\n",
855 		    fill_set->freq);
856 		free(fill, M_TEMP);
857 		fill = NULL;
858 	}
859 
860 	return (fill);
861 }
862 
863 static int
864 cpufreq_curr_sysctl(SYSCTL_HANDLER_ARGS)
865 {
866 	struct cpufreq_softc *sc;
867 	struct cf_level *levels;
868 	int count, devcount, error, freq, i, n;
869 	device_t *devs;
870 
871 	devs = NULL;
872 	sc = oidp->oid_arg1;
873 	levels = malloc(CF_MAX_LEVELS * sizeof(*levels), M_TEMP, M_NOWAIT);
874 	if (levels == NULL)
875 		return (ENOMEM);
876 
877 	error = CPUFREQ_GET(sc->dev, &levels[0]);
878 	if (error)
879 		goto out;
880 	freq = levels[0].total_set.freq;
881 	error = sysctl_handle_int(oidp, &freq, 0, req);
882 	if (error != 0 || req->newptr == NULL)
883 		goto out;
884 
885 	/*
886 	 * While we only call cpufreq_get() on one device (assuming all
887 	 * CPUs have equal levels), we call cpufreq_set() on all CPUs.
888 	 * This is needed for some MP systems.
889 	 */
890 	error = devclass_get_devices(cpufreq_dc, &devs, &devcount);
891 	if (error)
892 		goto out;
893 	for (n = 0; n < devcount; n++) {
894 		count = CF_MAX_LEVELS;
895 		error = CPUFREQ_LEVELS(devs[n], levels, &count);
896 		if (error) {
897 			if (error == E2BIG)
898 				printf(
899 			"cpufreq: need to increase CF_MAX_LEVELS\n");
900 			break;
901 		}
902 		for (i = 0; i < count; i++) {
903 			if (CPUFREQ_CMP(levels[i].total_set.freq, freq)) {
904 				error = CPUFREQ_SET(devs[n], &levels[i],
905 				    CPUFREQ_PRIO_USER);
906 				break;
907 			}
908 		}
909 		if (i == count) {
910 			error = EINVAL;
911 			break;
912 		}
913 	}
914 
915 out:
916 	if (devs)
917 		free(devs, M_TEMP);
918 	if (levels)
919 		free(levels, M_TEMP);
920 	return (error);
921 }
922 
923 static int
924 cpufreq_levels_sysctl(SYSCTL_HANDLER_ARGS)
925 {
926 	struct cpufreq_softc *sc;
927 	struct cf_level *levels;
928 	struct cf_setting *set;
929 	struct sbuf sb;
930 	int count, error, i;
931 
932 	sc = oidp->oid_arg1;
933 	sbuf_new(&sb, NULL, 128, SBUF_AUTOEXTEND);
934 
935 	/* Get settings from the device and generate the output string. */
936 	count = CF_MAX_LEVELS;
937 	levels = malloc(count * sizeof(*levels), M_TEMP, M_NOWAIT);
938 	if (levels == NULL) {
939 		sbuf_delete(&sb);
940 		return (ENOMEM);
941 	}
942 	error = CPUFREQ_LEVELS(sc->dev, levels, &count);
943 	if (error) {
944 		if (error == E2BIG)
945 			printf("cpufreq: need to increase CF_MAX_LEVELS\n");
946 		goto out;
947 	}
948 	if (count) {
949 		for (i = 0; i < count; i++) {
950 			set = &levels[i].total_set;
951 			sbuf_printf(&sb, "%d/%d ", set->freq, set->power);
952 		}
953 	} else
954 		sbuf_cpy(&sb, "0");
955 	sbuf_trim(&sb);
956 	sbuf_finish(&sb);
957 	error = sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req);
958 
959 out:
960 	free(levels, M_TEMP);
961 	sbuf_delete(&sb);
962 	return (error);
963 }
964 
965 static int
966 cpufreq_settings_sysctl(SYSCTL_HANDLER_ARGS)
967 {
968 	device_t dev;
969 	struct cf_setting *sets;
970 	struct sbuf sb;
971 	int error, i, set_count;
972 
973 	dev = oidp->oid_arg1;
974 	sbuf_new(&sb, NULL, 128, SBUF_AUTOEXTEND);
975 
976 	/* Get settings from the device and generate the output string. */
977 	set_count = MAX_SETTINGS;
978 	sets = malloc(set_count * sizeof(*sets), M_TEMP, M_NOWAIT);
979 	if (sets == NULL) {
980 		sbuf_delete(&sb);
981 		return (ENOMEM);
982 	}
983 	error = CPUFREQ_DRV_SETTINGS(dev, sets, &set_count);
984 	if (error)
985 		goto out;
986 	if (set_count) {
987 		for (i = 0; i < set_count; i++)
988 			sbuf_printf(&sb, "%d/%d ", sets[i].freq, sets[i].power);
989 	} else
990 		sbuf_cpy(&sb, "0");
991 	sbuf_trim(&sb);
992 	sbuf_finish(&sb);
993 	error = sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req);
994 
995 out:
996 	free(sets, M_TEMP);
997 	sbuf_delete(&sb);
998 	return (error);
999 }
1000 
1001 int
1002 cpufreq_register(device_t dev)
1003 {
1004 	struct cpufreq_softc *sc;
1005 	device_t cf_dev, cpu_dev;
1006 
1007 	/* Add a sysctl to get each driver's settings separately. */
1008 	SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
1009 	    SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
1010 	    OID_AUTO, "freq_settings", CTLTYPE_STRING | CTLFLAG_RD, dev, 0,
1011 	    cpufreq_settings_sysctl, "A", "CPU frequency driver settings");
1012 
1013 	/*
1014 	 * Add only one cpufreq device to each CPU.  Currently, all CPUs
1015 	 * must offer the same levels and be switched at the same time.
1016 	 */
1017 	cpu_dev = device_get_parent(dev);
1018 	if ((cf_dev = device_find_child(cpu_dev, "cpufreq", -1))) {
1019 		sc = device_get_softc(cf_dev);
1020 		sc->max_mhz = CPUFREQ_VAL_UNKNOWN;
1021 		return (0);
1022 	}
1023 
1024 	/* Add the child device and possibly sysctls. */
1025 	cf_dev = BUS_ADD_CHILD(cpu_dev, 0, "cpufreq", -1);
1026 	if (cf_dev == NULL)
1027 		return (ENOMEM);
1028 	device_quiet(cf_dev);
1029 
1030 	return (device_probe_and_attach(cf_dev));
1031 }
1032 
1033 int
1034 cpufreq_unregister(device_t dev)
1035 {
1036 	device_t cf_dev, *devs;
1037 	int cfcount, devcount, error, i, type;
1038 
1039 	/*
1040 	 * If this is the last cpufreq child device, remove the control
1041 	 * device as well.  We identify cpufreq children by calling a method
1042 	 * they support.
1043 	 */
1044 	error = device_get_children(device_get_parent(dev), &devs, &devcount);
1045 	if (error)
1046 		return (error);
1047 	cf_dev = device_find_child(device_get_parent(dev), "cpufreq", -1);
1048 	if (cf_dev == NULL) {
1049 		device_printf(dev,
1050 	"warning: cpufreq_unregister called with no cpufreq device active\n");
1051 		return (0);
1052 	}
1053 	cfcount = 0;
1054 	for (i = 0; i < devcount; i++) {
1055 		if (!device_is_attached(devs[i]))
1056 			continue;
1057 		if (CPUFREQ_DRV_TYPE(devs[i], &type) == 0)
1058 			cfcount++;
1059 	}
1060 	if (cfcount <= 1)
1061 		device_delete_child(device_get_parent(cf_dev), cf_dev);
1062 	free(devs, M_TEMP);
1063 
1064 	return (0);
1065 }
1066 
1067 int
1068 cpufreq_settings_changed(device_t dev)
1069 {
1070 
1071 	EVENTHANDLER_INVOKE(cpufreq_levels_changed,
1072 	    device_get_unit(device_get_parent(dev)));
1073 	return (0);
1074 }
1075