xref: /freebsd/sys/kern/kern_cpu.c (revision 130d950cafcd29c6a32cf5357bf600dcd9c1d998)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2004-2007 Nate Lawson (SDG)
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  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/bus.h>
34 #include <sys/cpu.h>
35 #include <sys/eventhandler.h>
36 #include <sys/kernel.h>
37 #include <sys/lock.h>
38 #include <sys/malloc.h>
39 #include <sys/module.h>
40 #include <sys/proc.h>
41 #include <sys/queue.h>
42 #include <sys/sbuf.h>
43 #include <sys/sched.h>
44 #include <sys/smp.h>
45 #include <sys/sysctl.h>
46 #include <sys/systm.h>
47 #include <sys/sx.h>
48 #include <sys/timetc.h>
49 #include <sys/taskqueue.h>
50 
51 #include "cpufreq_if.h"
52 
53 /*
54  * Common CPU frequency glue code.  Drivers for specific hardware can
55  * attach this interface to allow users to get/set the CPU frequency.
56  */
57 
58 /*
59  * Number of levels we can handle.  Levels are synthesized from settings
60  * so for M settings and N drivers, there may be M*N levels.
61  */
62 #define CF_MAX_LEVELS	256
63 
64 struct cf_saved_freq {
65 	struct cf_level			level;
66 	int				priority;
67 	SLIST_ENTRY(cf_saved_freq)	link;
68 };
69 
70 struct cpufreq_softc {
71 	struct sx			lock;
72 	struct cf_level			curr_level;
73 	int				curr_priority;
74 	SLIST_HEAD(, cf_saved_freq)	saved_freq;
75 	struct cf_level_lst		all_levels;
76 	int				all_count;
77 	int				max_mhz;
78 	device_t			dev;
79 	device_t			cf_drv_dev;
80 	struct sysctl_ctx_list		sysctl_ctx;
81 	struct task			startup_task;
82 	struct cf_level			*levels_buf;
83 };
84 
85 struct cf_setting_array {
86 	struct cf_setting		sets[MAX_SETTINGS];
87 	int				count;
88 	TAILQ_ENTRY(cf_setting_array)	link;
89 };
90 
91 TAILQ_HEAD(cf_setting_lst, cf_setting_array);
92 
93 #define CF_MTX_INIT(x)		sx_init((x), "cpufreq lock")
94 #define CF_MTX_LOCK(x)		sx_xlock((x))
95 #define CF_MTX_UNLOCK(x)	sx_xunlock((x))
96 #define CF_MTX_ASSERT(x)	sx_assert((x), SX_XLOCKED)
97 
98 #define CF_DEBUG(msg...)	do {		\
99 	if (cf_verbose)				\
100 		printf("cpufreq: " msg);	\
101 	} while (0)
102 
103 static int	cpufreq_attach(device_t dev);
104 static void	cpufreq_startup_task(void *ctx, int pending);
105 static int	cpufreq_detach(device_t dev);
106 static int	cf_set_method(device_t dev, const struct cf_level *level,
107 		    int priority);
108 static int	cf_get_method(device_t dev, struct cf_level *level);
109 static int	cf_levels_method(device_t dev, struct cf_level *levels,
110 		    int *count);
111 static int	cpufreq_insert_abs(struct cpufreq_softc *sc,
112 		    struct cf_setting *sets, int count);
113 static int	cpufreq_expand_set(struct cpufreq_softc *sc,
114 		    struct cf_setting_array *set_arr);
115 static struct cf_level *cpufreq_dup_set(struct cpufreq_softc *sc,
116 		    struct cf_level *dup, struct cf_setting *set);
117 static int	cpufreq_curr_sysctl(SYSCTL_HANDLER_ARGS);
118 static int	cpufreq_levels_sysctl(SYSCTL_HANDLER_ARGS);
119 static int	cpufreq_settings_sysctl(SYSCTL_HANDLER_ARGS);
120 
121 static device_method_t cpufreq_methods[] = {
122 	DEVMETHOD(device_probe,		bus_generic_probe),
123 	DEVMETHOD(device_attach,	cpufreq_attach),
124 	DEVMETHOD(device_detach,	cpufreq_detach),
125 
126         DEVMETHOD(cpufreq_set,		cf_set_method),
127         DEVMETHOD(cpufreq_get,		cf_get_method),
128         DEVMETHOD(cpufreq_levels,	cf_levels_method),
129 	{0, 0}
130 };
131 static driver_t cpufreq_driver = {
132 	"cpufreq", cpufreq_methods, sizeof(struct cpufreq_softc)
133 };
134 static devclass_t cpufreq_dc;
135 DRIVER_MODULE(cpufreq, cpu, cpufreq_driver, cpufreq_dc, 0, 0);
136 
137 static int		cf_lowest_freq;
138 static int		cf_verbose;
139 static SYSCTL_NODE(_debug, OID_AUTO, cpufreq, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL,
140     "cpufreq debugging");
141 SYSCTL_INT(_debug_cpufreq, OID_AUTO, lowest, CTLFLAG_RWTUN, &cf_lowest_freq, 1,
142     "Don't provide levels below this frequency.");
143 SYSCTL_INT(_debug_cpufreq, OID_AUTO, verbose, CTLFLAG_RWTUN, &cf_verbose, 1,
144     "Print verbose debugging messages");
145 
146 /*
147  * This is called as the result of a hardware specific frequency control driver
148  * calling cpufreq_register. It provides a general interface for system wide
149  * frequency controls and operates on a per cpu basis.
150  */
151 static int
152 cpufreq_attach(device_t dev)
153 {
154 	struct cpufreq_softc *sc;
155 	struct pcpu *pc;
156 	device_t parent;
157 	uint64_t rate;
158 
159 	CF_DEBUG("initializing %s\n", device_get_nameunit(dev));
160 	sc = device_get_softc(dev);
161 	parent = device_get_parent(dev);
162 	sc->dev = dev;
163 	sysctl_ctx_init(&sc->sysctl_ctx);
164 	TAILQ_INIT(&sc->all_levels);
165 	CF_MTX_INIT(&sc->lock);
166 	sc->curr_level.total_set.freq = CPUFREQ_VAL_UNKNOWN;
167 	SLIST_INIT(&sc->saved_freq);
168 	/* Try to get nominal CPU freq to use it as maximum later if needed */
169 	sc->max_mhz = cpu_get_nominal_mhz(dev);
170 	/* If that fails, try to measure the current rate */
171 	if (sc->max_mhz <= 0) {
172 		CF_DEBUG("Unable to obtain nominal frequency.\n");
173 		pc = cpu_get_pcpu(dev);
174 		if (cpu_est_clockrate(pc->pc_cpuid, &rate) == 0)
175 			sc->max_mhz = rate / 1000000;
176 		else
177 			sc->max_mhz = CPUFREQ_VAL_UNKNOWN;
178 	}
179 
180 	CF_DEBUG("initializing one-time data for %s\n",
181 	    device_get_nameunit(dev));
182 	sc->levels_buf = malloc(CF_MAX_LEVELS * sizeof(*sc->levels_buf),
183 	    M_DEVBUF, M_WAITOK);
184 	SYSCTL_ADD_PROC(&sc->sysctl_ctx,
185 	    SYSCTL_CHILDREN(device_get_sysctl_tree(parent)),
186 	    OID_AUTO, "freq", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
187 	    sc, 0, cpufreq_curr_sysctl, "I", "Current CPU frequency");
188 	SYSCTL_ADD_PROC(&sc->sysctl_ctx,
189 	    SYSCTL_CHILDREN(device_get_sysctl_tree(parent)),
190 	    OID_AUTO, "freq_levels",
191 	    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_NEEDGIANT, sc, 0,
192 	    cpufreq_levels_sysctl, "A", "CPU frequency levels");
193 
194 	/*
195 	 * Queue a one-shot broadcast that levels have changed.
196 	 * It will run once the system has completed booting.
197 	 */
198 	TASK_INIT(&sc->startup_task, 0, cpufreq_startup_task, dev);
199 	taskqueue_enqueue(taskqueue_thread, &sc->startup_task);
200 
201 	return (0);
202 }
203 
204 /* Handle any work to be done for all drivers that attached during boot. */
205 static void
206 cpufreq_startup_task(void *ctx, int pending)
207 {
208 
209 	cpufreq_settings_changed((device_t)ctx);
210 }
211 
212 static int
213 cpufreq_detach(device_t dev)
214 {
215 	struct cpufreq_softc *sc;
216 	struct cf_saved_freq *saved_freq;
217 
218 	CF_DEBUG("shutdown %s\n", device_get_nameunit(dev));
219 	sc = device_get_softc(dev);
220 	sysctl_ctx_free(&sc->sysctl_ctx);
221 
222 	while ((saved_freq = SLIST_FIRST(&sc->saved_freq)) != NULL) {
223 		SLIST_REMOVE_HEAD(&sc->saved_freq, link);
224 		free(saved_freq, M_TEMP);
225 	}
226 
227 	free(sc->levels_buf, M_DEVBUF);
228 
229 	return (0);
230 }
231 
232 static int
233 cf_set_method(device_t dev, const struct cf_level *level, int priority)
234 {
235 	struct cpufreq_softc *sc;
236 	const struct cf_setting *set;
237 	struct cf_saved_freq *saved_freq, *curr_freq;
238 	struct pcpu *pc;
239 	int error, i;
240 	u_char pri;
241 
242 	sc = device_get_softc(dev);
243 	error = 0;
244 	set = NULL;
245 	saved_freq = NULL;
246 
247 	/* We are going to change levels so notify the pre-change handler. */
248 	EVENTHANDLER_INVOKE(cpufreq_pre_change, level, &error);
249 	if (error != 0) {
250 		EVENTHANDLER_INVOKE(cpufreq_post_change, level, error);
251 		return (error);
252 	}
253 
254 	CF_MTX_LOCK(&sc->lock);
255 
256 #ifdef SMP
257 #ifdef EARLY_AP_STARTUP
258 	MPASS(mp_ncpus == 1 || smp_started);
259 #else
260 	/*
261 	 * If still booting and secondary CPUs not started yet, don't allow
262 	 * changing the frequency until they're online.  This is because we
263 	 * can't switch to them using sched_bind() and thus we'd only be
264 	 * switching the main CPU.  XXXTODO: Need to think more about how to
265 	 * handle having different CPUs at different frequencies.
266 	 */
267 	if (mp_ncpus > 1 && !smp_started) {
268 		device_printf(dev, "rejecting change, SMP not started yet\n");
269 		error = ENXIO;
270 		goto out;
271 	}
272 #endif
273 #endif /* SMP */
274 
275 	/*
276 	 * If the requested level has a lower priority, don't allow
277 	 * the new level right now.
278 	 */
279 	if (priority < sc->curr_priority) {
280 		CF_DEBUG("ignoring, curr prio %d less than %d\n", priority,
281 		    sc->curr_priority);
282 		error = EPERM;
283 		goto out;
284 	}
285 
286 	/*
287 	 * If the caller didn't specify a level and one is saved, prepare to
288 	 * restore the saved level.  If none has been saved, return an error.
289 	 */
290 	if (level == NULL) {
291 		saved_freq = SLIST_FIRST(&sc->saved_freq);
292 		if (saved_freq == NULL) {
293 			CF_DEBUG("NULL level, no saved level\n");
294 			error = ENXIO;
295 			goto out;
296 		}
297 		level = &saved_freq->level;
298 		priority = saved_freq->priority;
299 		CF_DEBUG("restoring saved level, freq %d prio %d\n",
300 		    level->total_set.freq, priority);
301 	}
302 
303 	/* Reject levels that are below our specified threshold. */
304 	if (level->total_set.freq < cf_lowest_freq) {
305 		CF_DEBUG("rejecting freq %d, less than %d limit\n",
306 		    level->total_set.freq, cf_lowest_freq);
307 		error = EINVAL;
308 		goto out;
309 	}
310 
311 	/* If already at this level, just return. */
312 	if (sc->curr_level.total_set.freq == level->total_set.freq) {
313 		CF_DEBUG("skipping freq %d, same as current level %d\n",
314 		    level->total_set.freq, sc->curr_level.total_set.freq);
315 		goto skip;
316 	}
317 
318 	/* First, set the absolute frequency via its driver. */
319 	set = &level->abs_set;
320 	if (set->dev) {
321 		if (!device_is_attached(set->dev)) {
322 			error = ENXIO;
323 			goto out;
324 		}
325 
326 		/* Bind to the target CPU before switching. */
327 		pc = cpu_get_pcpu(set->dev);
328 		thread_lock(curthread);
329 		pri = curthread->td_priority;
330 		sched_prio(curthread, PRI_MIN);
331 		sched_bind(curthread, pc->pc_cpuid);
332 		thread_unlock(curthread);
333 		CF_DEBUG("setting abs freq %d on %s (cpu %d)\n", set->freq,
334 		    device_get_nameunit(set->dev), PCPU_GET(cpuid));
335 		error = CPUFREQ_DRV_SET(set->dev, set);
336 		thread_lock(curthread);
337 		sched_unbind(curthread);
338 		sched_prio(curthread, pri);
339 		thread_unlock(curthread);
340 		if (error) {
341 			goto out;
342 		}
343 	}
344 
345 	/* Next, set any/all relative frequencies via their drivers. */
346 	for (i = 0; i < level->rel_count; i++) {
347 		set = &level->rel_set[i];
348 		if (!device_is_attached(set->dev)) {
349 			error = ENXIO;
350 			goto out;
351 		}
352 
353 		/* Bind to the target CPU before switching. */
354 		pc = cpu_get_pcpu(set->dev);
355 		thread_lock(curthread);
356 		pri = curthread->td_priority;
357 		sched_prio(curthread, PRI_MIN);
358 		sched_bind(curthread, pc->pc_cpuid);
359 		thread_unlock(curthread);
360 		CF_DEBUG("setting rel freq %d on %s (cpu %d)\n", set->freq,
361 		    device_get_nameunit(set->dev), PCPU_GET(cpuid));
362 		error = CPUFREQ_DRV_SET(set->dev, set);
363 		thread_lock(curthread);
364 		sched_unbind(curthread);
365 		sched_prio(curthread, pri);
366 		thread_unlock(curthread);
367 		if (error) {
368 			/* XXX Back out any successful setting? */
369 			goto out;
370 		}
371 	}
372 
373 skip:
374 	/*
375 	 * Before recording the current level, check if we're going to a
376 	 * higher priority.  If so, save the previous level and priority.
377 	 */
378 	if (sc->curr_level.total_set.freq != CPUFREQ_VAL_UNKNOWN &&
379 	    priority > sc->curr_priority) {
380 		CF_DEBUG("saving level, freq %d prio %d\n",
381 		    sc->curr_level.total_set.freq, sc->curr_priority);
382 		curr_freq = malloc(sizeof(*curr_freq), M_TEMP, M_NOWAIT);
383 		if (curr_freq == NULL) {
384 			error = ENOMEM;
385 			goto out;
386 		}
387 		curr_freq->level = sc->curr_level;
388 		curr_freq->priority = sc->curr_priority;
389 		SLIST_INSERT_HEAD(&sc->saved_freq, curr_freq, link);
390 	}
391 	sc->curr_level = *level;
392 	sc->curr_priority = priority;
393 
394 	/* If we were restoring a saved state, reset it to "unused". */
395 	if (saved_freq != NULL) {
396 		CF_DEBUG("resetting saved level\n");
397 		sc->curr_level.total_set.freq = CPUFREQ_VAL_UNKNOWN;
398 		SLIST_REMOVE_HEAD(&sc->saved_freq, link);
399 		free(saved_freq, M_TEMP);
400 	}
401 
402 out:
403 	CF_MTX_UNLOCK(&sc->lock);
404 
405 	/*
406 	 * We changed levels (or attempted to) so notify the post-change
407 	 * handler of new frequency or error.
408 	 */
409 	EVENTHANDLER_INVOKE(cpufreq_post_change, level, error);
410 	if (error && set)
411 		device_printf(set->dev, "set freq failed, err %d\n", error);
412 
413 	return (error);
414 }
415 
416 static int
417 cpufreq_get_frequency(device_t dev)
418 {
419 	struct cf_setting set;
420 
421 	if (CPUFREQ_DRV_GET(dev, &set) != 0)
422 		return (-1);
423 
424 	return (set.freq);
425 }
426 
427 /* Returns the index into *levels with the match */
428 static int
429 cpufreq_get_level(device_t dev, struct cf_level *levels, int count)
430 {
431 	int i, freq;
432 
433 	if ((freq = cpufreq_get_frequency(dev)) < 0)
434 		return (-1);
435 	for (i = 0; i < count; i++)
436 		if (freq == levels[i].total_set.freq)
437 			return (i);
438 
439 	return (-1);
440 }
441 
442 /*
443  * Used by the cpufreq core, this function will populate *level with the current
444  * frequency as either determined by a cached value sc->curr_level, or in the
445  * case the lower level driver has set the CPUFREQ_FLAG_UNCACHED flag, it will
446  * obtain the frequency from the driver itself.
447  */
448 static int
449 cf_get_method(device_t dev, struct cf_level *level)
450 {
451 	struct cpufreq_softc *sc;
452 	struct cf_level *levels;
453 	struct cf_setting *curr_set;
454 	struct pcpu *pc;
455 	int bdiff, count, diff, error, i, type;
456 	uint64_t rate;
457 
458 	sc = device_get_softc(dev);
459 	error = 0;
460 	levels = NULL;
461 
462 	/*
463 	 * If we already know the current frequency, and the driver didn't ask
464 	 * for uncached usage, we're done.
465 	 */
466 	CF_MTX_LOCK(&sc->lock);
467 	curr_set = &sc->curr_level.total_set;
468 	error = CPUFREQ_DRV_TYPE(sc->cf_drv_dev, &type);
469 	if (error == 0 && (type & CPUFREQ_FLAG_UNCACHED)) {
470 		struct cf_setting set;
471 
472 		/*
473 		 * If the driver wants to always report back the real frequency,
474 		 * first try the driver and if that fails, fall back to
475 		 * estimating.
476 		 */
477 		if (CPUFREQ_DRV_GET(sc->cf_drv_dev, &set) == 0) {
478 			sc->curr_level.total_set = set;
479 			CF_DEBUG("get returning immediate freq %d\n",
480 			    curr_set->freq);
481 			goto out;
482 		}
483 	} else if (curr_set->freq != CPUFREQ_VAL_UNKNOWN) {
484 		CF_DEBUG("get returning known freq %d\n", curr_set->freq);
485 		error = 0;
486 		goto out;
487 	}
488 	CF_MTX_UNLOCK(&sc->lock);
489 
490 	/*
491 	 * We need to figure out the current level.  Loop through every
492 	 * driver, getting the current setting.  Then, attempt to get a best
493 	 * match of settings against each level.
494 	 */
495 	count = CF_MAX_LEVELS;
496 	levels = malloc(count * sizeof(*levels), M_TEMP, M_NOWAIT);
497 	if (levels == NULL)
498 		return (ENOMEM);
499 	error = CPUFREQ_LEVELS(sc->dev, levels, &count);
500 	if (error) {
501 		if (error == E2BIG)
502 			printf("cpufreq: need to increase CF_MAX_LEVELS\n");
503 		free(levels, M_TEMP);
504 		return (error);
505 	}
506 
507 	/*
508 	 * Reacquire the lock and search for the given level.
509 	 *
510 	 * XXX Note: this is not quite right since we really need to go
511 	 * through each level and compare both absolute and relative
512 	 * settings for each driver in the system before making a match.
513 	 * The estimation code below catches this case though.
514 	 */
515 	CF_MTX_LOCK(&sc->lock);
516 	i = cpufreq_get_level(sc->cf_drv_dev, levels, count);
517 	if (i >= 0)
518 		sc->curr_level = levels[i];
519 	else
520 		CF_DEBUG("Couldn't find supported level for %s\n",
521 		    device_get_nameunit(sc->cf_drv_dev));
522 
523 	if (curr_set->freq != CPUFREQ_VAL_UNKNOWN) {
524 		CF_DEBUG("get matched freq %d from drivers\n", curr_set->freq);
525 		goto out;
526 	}
527 
528 	/*
529 	 * We couldn't find an exact match, so attempt to estimate and then
530 	 * match against a level.
531 	 */
532 	pc = cpu_get_pcpu(dev);
533 	if (pc == NULL) {
534 		error = ENXIO;
535 		goto out;
536 	}
537 	cpu_est_clockrate(pc->pc_cpuid, &rate);
538 	rate /= 1000000;
539 	bdiff = 1 << 30;
540 	for (i = 0; i < count; i++) {
541 		diff = abs(levels[i].total_set.freq - rate);
542 		if (diff < bdiff) {
543 			bdiff = diff;
544 			sc->curr_level = levels[i];
545 		}
546 	}
547 	CF_DEBUG("get estimated freq %d\n", curr_set->freq);
548 
549 out:
550 	if (error == 0)
551 		*level = sc->curr_level;
552 
553 	CF_MTX_UNLOCK(&sc->lock);
554 	if (levels)
555 		free(levels, M_TEMP);
556 	return (error);
557 }
558 
559 /*
560  * Either directly obtain settings from the cpufreq driver, or build a list of
561  * relative settings to be integrated later against an absolute max.
562  */
563 static int
564 cpufreq_add_levels(device_t cf_dev, struct cf_setting_lst *rel_sets)
565 {
566 	struct cf_setting_array *set_arr;
567 	struct cf_setting *sets;
568 	device_t dev;
569 	struct cpufreq_softc *sc;
570 	int type, set_count, error;
571 
572 	sc = device_get_softc(cf_dev);
573 	dev = sc->cf_drv_dev;
574 
575 	/* Skip devices that aren't ready. */
576 	if (!device_is_attached(cf_dev))
577 		return (0);
578 
579 	/*
580 	 * Get settings, skipping drivers that offer no settings or
581 	 * provide settings for informational purposes only.
582 	 */
583 	error = CPUFREQ_DRV_TYPE(dev, &type);
584 	if (error != 0 || (type & CPUFREQ_FLAG_INFO_ONLY)) {
585 		if (error == 0) {
586 			CF_DEBUG("skipping info-only driver %s\n",
587 			    device_get_nameunit(cf_dev));
588 		}
589 		return (error);
590 	}
591 
592 	sets = malloc(MAX_SETTINGS * sizeof(*sets), M_TEMP, M_NOWAIT);
593 	if (sets == NULL)
594 		return (ENOMEM);
595 
596 	set_count = MAX_SETTINGS;
597 	error = CPUFREQ_DRV_SETTINGS(dev, sets, &set_count);
598 	if (error != 0 || set_count == 0)
599 		goto out;
600 
601 	/* Add the settings to our absolute/relative lists. */
602 	switch (type & CPUFREQ_TYPE_MASK) {
603 	case CPUFREQ_TYPE_ABSOLUTE:
604 		error = cpufreq_insert_abs(sc, sets, set_count);
605 		break;
606 	case CPUFREQ_TYPE_RELATIVE:
607 		CF_DEBUG("adding %d relative settings\n", set_count);
608 		set_arr = malloc(sizeof(*set_arr), M_TEMP, M_NOWAIT);
609 		if (set_arr == NULL) {
610 			error = ENOMEM;
611 			goto out;
612 		}
613 		bcopy(sets, set_arr->sets, set_count * sizeof(*sets));
614 		set_arr->count = set_count;
615 		TAILQ_INSERT_TAIL(rel_sets, set_arr, link);
616 		break;
617 	default:
618 		error = EINVAL;
619 	}
620 
621 out:
622 	free(sets, M_TEMP);
623 	return (error);
624 }
625 
626 static int
627 cf_levels_method(device_t dev, struct cf_level *levels, int *count)
628 {
629 	struct cf_setting_array *set_arr;
630 	struct cf_setting_lst rel_sets;
631 	struct cpufreq_softc *sc;
632 	struct cf_level *lev;
633 	struct pcpu *pc;
634 	int error, i;
635 	uint64_t rate;
636 
637 	if (levels == NULL || count == NULL)
638 		return (EINVAL);
639 
640 	TAILQ_INIT(&rel_sets);
641 	sc = device_get_softc(dev);
642 
643 	CF_MTX_LOCK(&sc->lock);
644 	error = cpufreq_add_levels(sc->dev, &rel_sets);
645 	if (error)
646 		goto out;
647 
648 	/*
649 	 * If there are no absolute levels, create a fake one at 100%.  We
650 	 * then cache the clockrate for later use as our base frequency.
651 	 */
652 	if (TAILQ_EMPTY(&sc->all_levels)) {
653 		struct cf_setting set;
654 
655 		CF_DEBUG("No absolute levels returned by driver\n");
656 
657 		if (sc->max_mhz == CPUFREQ_VAL_UNKNOWN) {
658 			sc->max_mhz = cpu_get_nominal_mhz(dev);
659 			/*
660 			 * If the CPU can't report a rate for 100%, hope
661 			 * the CPU is running at its nominal rate right now,
662 			 * and use that instead.
663 			 */
664 			if (sc->max_mhz <= 0) {
665 				pc = cpu_get_pcpu(dev);
666 				cpu_est_clockrate(pc->pc_cpuid, &rate);
667 				sc->max_mhz = rate / 1000000;
668 			}
669 		}
670 		memset(&set, CPUFREQ_VAL_UNKNOWN, sizeof(set));
671 		set.freq = sc->max_mhz;
672 		set.dev = NULL;
673 		error = cpufreq_insert_abs(sc, &set, 1);
674 		if (error)
675 			goto out;
676 	}
677 
678 	/* Create a combined list of absolute + relative levels. */
679 	TAILQ_FOREACH(set_arr, &rel_sets, link)
680 		cpufreq_expand_set(sc, set_arr);
681 
682 	/* If the caller doesn't have enough space, return the actual count. */
683 	if (sc->all_count > *count) {
684 		*count = sc->all_count;
685 		error = E2BIG;
686 		goto out;
687 	}
688 
689 	/* Finally, output the list of levels. */
690 	i = 0;
691 	TAILQ_FOREACH(lev, &sc->all_levels, link) {
692 
693 		/* Skip levels that have a frequency that is too low. */
694 		if (lev->total_set.freq < cf_lowest_freq) {
695 			sc->all_count--;
696 			continue;
697 		}
698 
699 		levels[i] = *lev;
700 		i++;
701 	}
702 	*count = sc->all_count;
703 	error = 0;
704 
705 out:
706 	/* Clear all levels since we regenerate them each time. */
707 	while ((lev = TAILQ_FIRST(&sc->all_levels)) != NULL) {
708 		TAILQ_REMOVE(&sc->all_levels, lev, link);
709 		free(lev, M_TEMP);
710 	}
711 	sc->all_count = 0;
712 
713 	CF_MTX_UNLOCK(&sc->lock);
714 	while ((set_arr = TAILQ_FIRST(&rel_sets)) != NULL) {
715 		TAILQ_REMOVE(&rel_sets, set_arr, link);
716 		free(set_arr, M_TEMP);
717 	}
718 	return (error);
719 }
720 
721 /*
722  * Create levels for an array of absolute settings and insert them in
723  * sorted order in the specified list.
724  */
725 static int
726 cpufreq_insert_abs(struct cpufreq_softc *sc, struct cf_setting *sets,
727     int count)
728 {
729 	struct cf_level_lst *list;
730 	struct cf_level *level, *search;
731 	int i, inserted;
732 
733 	CF_MTX_ASSERT(&sc->lock);
734 
735 	list = &sc->all_levels;
736 	for (i = 0; i < count; i++) {
737 		level = malloc(sizeof(*level), M_TEMP, M_NOWAIT | M_ZERO);
738 		if (level == NULL)
739 			return (ENOMEM);
740 		level->abs_set = sets[i];
741 		level->total_set = sets[i];
742 		level->total_set.dev = NULL;
743 		sc->all_count++;
744 		inserted = 0;
745 
746 		if (TAILQ_EMPTY(list)) {
747 			CF_DEBUG("adding abs setting %d at head\n",
748 			    sets[i].freq);
749 			TAILQ_INSERT_HEAD(list, level, link);
750 			continue;
751 		}
752 
753 		TAILQ_FOREACH_REVERSE(search, list, cf_level_lst, link)
754 			if (sets[i].freq <= search->total_set.freq) {
755 				CF_DEBUG("adding abs setting %d after %d\n",
756 				    sets[i].freq, search->total_set.freq);
757 				TAILQ_INSERT_AFTER(list, search, level, link);
758 				inserted = 1;
759 				break;
760 			}
761 
762 		if (inserted == 0) {
763 			TAILQ_FOREACH(search, list, link)
764 				if (sets[i].freq >= search->total_set.freq) {
765 					CF_DEBUG("adding abs setting %d before %d\n",
766 					    sets[i].freq, search->total_set.freq);
767 					TAILQ_INSERT_BEFORE(search, level, link);
768 					break;
769 				}
770 		}
771 	}
772 
773 	return (0);
774 }
775 
776 /*
777  * Expand a group of relative settings, creating derived levels from them.
778  */
779 static int
780 cpufreq_expand_set(struct cpufreq_softc *sc, struct cf_setting_array *set_arr)
781 {
782 	struct cf_level *fill, *search;
783 	struct cf_setting *set;
784 	int i;
785 
786 	CF_MTX_ASSERT(&sc->lock);
787 
788 	/*
789 	 * Walk the set of all existing levels in reverse.  This is so we
790 	 * create derived states from the lowest absolute settings first
791 	 * and discard duplicates created from higher absolute settings.
792 	 * For instance, a level of 50 Mhz derived from 100 Mhz + 50% is
793 	 * preferable to 200 Mhz + 25% because absolute settings are more
794 	 * efficient since they often change the voltage as well.
795 	 */
796 	TAILQ_FOREACH_REVERSE(search, &sc->all_levels, cf_level_lst, link) {
797 		/* Add each setting to the level, duplicating if necessary. */
798 		for (i = 0; i < set_arr->count; i++) {
799 			set = &set_arr->sets[i];
800 
801 			/*
802 			 * If this setting is less than 100%, split the level
803 			 * into two and add this setting to the new level.
804 			 */
805 			fill = search;
806 			if (set->freq < 10000) {
807 				fill = cpufreq_dup_set(sc, search, set);
808 
809 				/*
810 				 * The new level was a duplicate of an existing
811 				 * level or its absolute setting is too high
812 				 * so we freed it.  For example, we discard a
813 				 * derived level of 1000 MHz/25% if a level
814 				 * of 500 MHz/100% already exists.
815 				 */
816 				if (fill == NULL)
817 					break;
818 			}
819 
820 			/* Add this setting to the existing or new level. */
821 			KASSERT(fill->rel_count < MAX_SETTINGS,
822 			    ("cpufreq: too many relative drivers (%d)",
823 			    MAX_SETTINGS));
824 			fill->rel_set[fill->rel_count] = *set;
825 			fill->rel_count++;
826 			CF_DEBUG(
827 			"expand set added rel setting %d%% to %d level\n",
828 			    set->freq / 100, fill->total_set.freq);
829 		}
830 	}
831 
832 	return (0);
833 }
834 
835 static struct cf_level *
836 cpufreq_dup_set(struct cpufreq_softc *sc, struct cf_level *dup,
837     struct cf_setting *set)
838 {
839 	struct cf_level_lst *list;
840 	struct cf_level *fill, *itr;
841 	struct cf_setting *fill_set, *itr_set;
842 	int i;
843 
844 	CF_MTX_ASSERT(&sc->lock);
845 
846 	/*
847 	 * Create a new level, copy it from the old one, and update the
848 	 * total frequency and power by the percentage specified in the
849 	 * relative setting.
850 	 */
851 	fill = malloc(sizeof(*fill), M_TEMP, M_NOWAIT);
852 	if (fill == NULL)
853 		return (NULL);
854 	*fill = *dup;
855 	fill_set = &fill->total_set;
856 	fill_set->freq =
857 	    ((uint64_t)fill_set->freq * set->freq) / 10000;
858 	if (fill_set->power != CPUFREQ_VAL_UNKNOWN) {
859 		fill_set->power = ((uint64_t)fill_set->power * set->freq)
860 		    / 10000;
861 	}
862 	if (set->lat != CPUFREQ_VAL_UNKNOWN) {
863 		if (fill_set->lat != CPUFREQ_VAL_UNKNOWN)
864 			fill_set->lat += set->lat;
865 		else
866 			fill_set->lat = set->lat;
867 	}
868 	CF_DEBUG("dup set considering derived setting %d\n", fill_set->freq);
869 
870 	/*
871 	 * If we copied an old level that we already modified (say, at 100%),
872 	 * we need to remove that setting before adding this one.  Since we
873 	 * process each setting array in order, we know any settings for this
874 	 * driver will be found at the end.
875 	 */
876 	for (i = fill->rel_count; i != 0; i--) {
877 		if (fill->rel_set[i - 1].dev != set->dev)
878 			break;
879 		CF_DEBUG("removed last relative driver: %s\n",
880 		    device_get_nameunit(set->dev));
881 		fill->rel_count--;
882 	}
883 
884 	/*
885 	 * Insert the new level in sorted order.  If it is a duplicate of an
886 	 * existing level (1) or has an absolute setting higher than the
887 	 * existing level (2), do not add it.  We can do this since any such
888 	 * level is guaranteed use less power.  For example (1), a level with
889 	 * one absolute setting of 800 Mhz uses less power than one composed
890 	 * of an absolute setting of 1600 Mhz and a relative setting at 50%.
891 	 * Also for example (2), a level of 800 Mhz/75% is preferable to
892 	 * 1600 Mhz/25% even though the latter has a lower total frequency.
893 	 */
894 	list = &sc->all_levels;
895 	KASSERT(!TAILQ_EMPTY(list), ("all levels list empty in dup set"));
896 	TAILQ_FOREACH_REVERSE(itr, list, cf_level_lst, link) {
897 		itr_set = &itr->total_set;
898 		if (CPUFREQ_CMP(fill_set->freq, itr_set->freq)) {
899 			CF_DEBUG("dup set rejecting %d (dupe)\n",
900 			    fill_set->freq);
901 			itr = NULL;
902 			break;
903 		} else if (fill_set->freq < itr_set->freq) {
904 			if (fill->abs_set.freq <= itr->abs_set.freq) {
905 				CF_DEBUG(
906 			"dup done, inserting new level %d after %d\n",
907 				    fill_set->freq, itr_set->freq);
908 				TAILQ_INSERT_AFTER(list, itr, fill, link);
909 				sc->all_count++;
910 			} else {
911 				CF_DEBUG("dup set rejecting %d (abs too big)\n",
912 				    fill_set->freq);
913 				itr = NULL;
914 			}
915 			break;
916 		}
917 	}
918 
919 	/* We didn't find a good place for this new level so free it. */
920 	if (itr == NULL) {
921 		CF_DEBUG("dup set freeing new level %d (not optimal)\n",
922 		    fill_set->freq);
923 		free(fill, M_TEMP);
924 		fill = NULL;
925 	}
926 
927 	return (fill);
928 }
929 
930 static int
931 cpufreq_curr_sysctl(SYSCTL_HANDLER_ARGS)
932 {
933 	struct cpufreq_softc *sc;
934 	struct cf_level *levels;
935 	int best, count, diff, bdiff, devcount, error, freq, i, n;
936 	device_t *devs;
937 
938 	devs = NULL;
939 	sc = oidp->oid_arg1;
940 	levels = sc->levels_buf;
941 
942 	error = CPUFREQ_GET(sc->dev, &levels[0]);
943 	if (error)
944 		goto out;
945 	freq = levels[0].total_set.freq;
946 	error = sysctl_handle_int(oidp, &freq, 0, req);
947 	if (error != 0 || req->newptr == NULL)
948 		goto out;
949 
950 	/*
951 	 * While we only call cpufreq_get() on one device (assuming all
952 	 * CPUs have equal levels), we call cpufreq_set() on all CPUs.
953 	 * This is needed for some MP systems.
954 	 */
955 	error = devclass_get_devices(cpufreq_dc, &devs, &devcount);
956 	if (error)
957 		goto out;
958 	for (n = 0; n < devcount; n++) {
959 		count = CF_MAX_LEVELS;
960 		error = CPUFREQ_LEVELS(devs[n], levels, &count);
961 		if (error) {
962 			if (error == E2BIG)
963 				printf(
964 			"cpufreq: need to increase CF_MAX_LEVELS\n");
965 			break;
966 		}
967 		best = 0;
968 		bdiff = 1 << 30;
969 		for (i = 0; i < count; i++) {
970 			diff = abs(levels[i].total_set.freq - freq);
971 			if (diff < bdiff) {
972 				bdiff = diff;
973 				best = i;
974 			}
975 		}
976 		error = CPUFREQ_SET(devs[n], &levels[best], CPUFREQ_PRIO_USER);
977 	}
978 
979 out:
980 	if (devs)
981 		free(devs, M_TEMP);
982 	return (error);
983 }
984 
985 static int
986 cpufreq_levels_sysctl(SYSCTL_HANDLER_ARGS)
987 {
988 	struct cpufreq_softc *sc;
989 	struct cf_level *levels;
990 	struct cf_setting *set;
991 	struct sbuf sb;
992 	int count, error, i;
993 
994 	sc = oidp->oid_arg1;
995 	sbuf_new(&sb, NULL, 128, SBUF_AUTOEXTEND);
996 
997 	/* Get settings from the device and generate the output string. */
998 	count = CF_MAX_LEVELS;
999 	levels = sc->levels_buf;
1000 	if (levels == NULL) {
1001 		sbuf_delete(&sb);
1002 		return (ENOMEM);
1003 	}
1004 	error = CPUFREQ_LEVELS(sc->dev, levels, &count);
1005 	if (error) {
1006 		if (error == E2BIG)
1007 			printf("cpufreq: need to increase CF_MAX_LEVELS\n");
1008 		goto out;
1009 	}
1010 	if (count) {
1011 		for (i = 0; i < count; i++) {
1012 			set = &levels[i].total_set;
1013 			sbuf_printf(&sb, "%d/%d ", set->freq, set->power);
1014 		}
1015 	} else
1016 		sbuf_cpy(&sb, "0");
1017 	sbuf_trim(&sb);
1018 	sbuf_finish(&sb);
1019 	error = sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req);
1020 
1021 out:
1022 	sbuf_delete(&sb);
1023 	return (error);
1024 }
1025 
1026 static int
1027 cpufreq_settings_sysctl(SYSCTL_HANDLER_ARGS)
1028 {
1029 	device_t dev;
1030 	struct cf_setting *sets;
1031 	struct sbuf sb;
1032 	int error, i, set_count;
1033 
1034 	dev = oidp->oid_arg1;
1035 	sbuf_new(&sb, NULL, 128, SBUF_AUTOEXTEND);
1036 
1037 	/* Get settings from the device and generate the output string. */
1038 	set_count = MAX_SETTINGS;
1039 	sets = malloc(set_count * sizeof(*sets), M_TEMP, M_NOWAIT);
1040 	if (sets == NULL) {
1041 		sbuf_delete(&sb);
1042 		return (ENOMEM);
1043 	}
1044 	error = CPUFREQ_DRV_SETTINGS(dev, sets, &set_count);
1045 	if (error)
1046 		goto out;
1047 	if (set_count) {
1048 		for (i = 0; i < set_count; i++)
1049 			sbuf_printf(&sb, "%d/%d ", sets[i].freq, sets[i].power);
1050 	} else
1051 		sbuf_cpy(&sb, "0");
1052 	sbuf_trim(&sb);
1053 	sbuf_finish(&sb);
1054 	error = sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req);
1055 
1056 out:
1057 	free(sets, M_TEMP);
1058 	sbuf_delete(&sb);
1059 	return (error);
1060 }
1061 
1062 static void
1063 cpufreq_add_freq_driver_sysctl(device_t cf_dev)
1064 {
1065 	struct cpufreq_softc *sc;
1066 
1067 	sc = device_get_softc(cf_dev);
1068 	SYSCTL_ADD_CONST_STRING(&sc->sysctl_ctx,
1069 	    SYSCTL_CHILDREN(device_get_sysctl_tree(cf_dev)), OID_AUTO,
1070 	    "freq_driver", CTLFLAG_RD, device_get_nameunit(sc->cf_drv_dev),
1071 	    "cpufreq driver used by this cpu");
1072 }
1073 
1074 int
1075 cpufreq_register(device_t dev)
1076 {
1077 	struct cpufreq_softc *sc;
1078 	device_t cf_dev, cpu_dev;
1079 	int error;
1080 
1081 	/* Add a sysctl to get each driver's settings separately. */
1082 	SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
1083 	    SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
1084 	    OID_AUTO, "freq_settings",
1085 	    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_NEEDGIANT, dev, 0,
1086 	    cpufreq_settings_sysctl, "A", "CPU frequency driver settings");
1087 
1088 	/*
1089 	 * Add only one cpufreq device to each CPU.  Currently, all CPUs
1090 	 * must offer the same levels and be switched at the same time.
1091 	 */
1092 	cpu_dev = device_get_parent(dev);
1093 	if ((cf_dev = device_find_child(cpu_dev, "cpufreq", -1))) {
1094 		sc = device_get_softc(cf_dev);
1095 		sc->max_mhz = CPUFREQ_VAL_UNKNOWN;
1096 		MPASS(sc->cf_drv_dev != NULL);
1097 		return (0);
1098 	}
1099 
1100 	/* Add the child device and possibly sysctls. */
1101 	cf_dev = BUS_ADD_CHILD(cpu_dev, 0, "cpufreq", -1);
1102 	if (cf_dev == NULL)
1103 		return (ENOMEM);
1104 	device_quiet(cf_dev);
1105 
1106 	error = device_probe_and_attach(cf_dev);
1107 	if (error)
1108 		return (error);
1109 
1110 	sc = device_get_softc(cf_dev);
1111 	sc->cf_drv_dev = dev;
1112 	cpufreq_add_freq_driver_sysctl(cf_dev);
1113 	return (error);
1114 }
1115 
1116 int
1117 cpufreq_unregister(device_t dev)
1118 {
1119 	device_t cf_dev;
1120 	struct cpufreq_softc *sc;
1121 
1122 	/*
1123 	 * If this is the last cpufreq child device, remove the control
1124 	 * device as well.  We identify cpufreq children by calling a method
1125 	 * they support.
1126 	 */
1127 	cf_dev = device_find_child(device_get_parent(dev), "cpufreq", -1);
1128 	if (cf_dev == NULL) {
1129 		device_printf(dev,
1130 	"warning: cpufreq_unregister called with no cpufreq device active\n");
1131 		return (0);
1132 	}
1133 	sc = device_get_softc(cf_dev);
1134 	MPASS(sc->cf_drv_dev == dev);
1135 	device_delete_child(device_get_parent(cf_dev), cf_dev);
1136 
1137 	return (0);
1138 }
1139 
1140 int
1141 cpufreq_settings_changed(device_t dev)
1142 {
1143 
1144 	EVENTHANDLER_INVOKE(cpufreq_levels_changed,
1145 	    device_get_unit(device_get_parent(dev)));
1146 	return (0);
1147 }
1148