sys/kern/kern_cpu.c

   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   64
  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         struct sysctl_ctx_list          sysctl_ctx;
  80         struct task                     startup_task;
  81         struct cf_level                 *levels_buf;
  82 };
  83
  84 struct cf_setting_array {
  85         struct cf_setting               sets[MAX_SETTINGS];
  86         int                             count;
  87         TAILQ_ENTRY(cf_setting_array)   link;
  88 };
  89
  90 TAILQ_HEAD(cf_setting_lst, cf_setting_array);
  91
  92 #define CF_MTX_INIT(x)          sx_init((x), "cpufreq lock")
  93 #define CF_MTX_LOCK(x)          sx_xlock((x))
  94 #define CF_MTX_UNLOCK(x)        sx_xunlock((x))
  95 #define CF_MTX_ASSERT(x)        sx_assert((x), SX_XLOCKED)
  96
  97 #define CF_DEBUG(msg...)        do {            \
  98         if (cf_verbose)                         \
  99                 printf("cpufreq: " msg);        \
 100         } while (0)
 101
 102 static int      cpufreq_attach(device_t dev);
 103 static void     cpufreq_startup_task(void *ctx, int pending);
 104 static int      cpufreq_detach(device_t dev);
 105 static int      cf_set_method(device_t dev, const struct cf_level *level,
 106                     int priority);
 107 static int      cf_get_method(device_t dev, struct cf_level *level);
 108 static int      cf_levels_method(device_t dev, struct cf_level *levels,
 109                     int *count);
 110 static int      cpufreq_insert_abs(struct cpufreq_softc *sc,
 111                     struct cf_setting *sets, int count);
 112 static int      cpufreq_expand_set(struct cpufreq_softc *sc,
 113                     struct cf_setting_array *set_arr);
 114 static struct cf_level *cpufreq_dup_set(struct cpufreq_softc *sc,
 115                     struct cf_level *dup, struct cf_setting *set);
 116 static int      cpufreq_curr_sysctl(SYSCTL_HANDLER_ARGS);
 117 static int      cpufreq_levels_sysctl(SYSCTL_HANDLER_ARGS);
 118 static int      cpufreq_settings_sysctl(SYSCTL_HANDLER_ARGS);
 119
 120 static device_method_t cpufreq_methods[] = {
 121         DEVMETHOD(device_probe,         bus_generic_probe),
 122         DEVMETHOD(device_attach,        cpufreq_attach),
 123         DEVMETHOD(device_detach,        cpufreq_detach),
 124
 125         DEVMETHOD(cpufreq_set,          cf_set_method),
 126         DEVMETHOD(cpufreq_get,          cf_get_method),
 127         DEVMETHOD(cpufreq_levels,       cf_levels_method),
 128         {0, 0}
 129 };
 130 static driver_t cpufreq_driver = {
 131         "cpufreq", cpufreq_methods, sizeof(struct cpufreq_softc)
 132 };
 133 static devclass_t cpufreq_dc;
 134 DRIVER_MODULE(cpufreq, cpu, cpufreq_driver, cpufreq_dc, 0, 0);
 135
 136 static int              cf_lowest_freq;
 137 static int              cf_verbose;
 138 static SYSCTL_NODE(_debug, OID_AUTO, cpufreq, CTLFLAG_RD, NULL,
 139     "cpufreq debugging");
 140 SYSCTL_INT(_debug_cpufreq, OID_AUTO, lowest, CTLFLAG_RWTUN, &cf_lowest_freq, 1,
 141     "Don't provide levels below this frequency.");
 142 SYSCTL_INT(_debug_cpufreq, OID_AUTO, verbose, CTLFLAG_RWTUN, &cf_verbose, 1,
 143     "Print verbose debugging messages");
 144
 145 static int
 146 cpufreq_attach(device_t dev)
 147 {
 148         struct cpufreq_softc *sc;
 149         struct pcpu *pc;
 150         device_t parent;
 151         uint64_t rate;
 152         int numdevs;
 153
 154         CF_DEBUG("initializing %s\n", device_get_nameunit(dev));
 155         sc = device_get_softc(dev);
 156         parent = device_get_parent(dev);
 157         sc->dev = dev;
 158         sysctl_ctx_init(&sc->sysctl_ctx);
 159         TAILQ_INIT(&sc->all_levels);
 160         CF_MTX_INIT(&sc->lock);
 161         sc->curr_level.total_set.freq = CPUFREQ_VAL_UNKNOWN;
 162         SLIST_INIT(&sc->saved_freq);
 163         /* Try to get nominal CPU freq to use it as maximum later if needed */
 164         sc->max_mhz = cpu_get_nominal_mhz(dev);
 165         /* If that fails, try to measure the current rate */
 166         if (sc->max_mhz <= 0) {
 167                 pc = cpu_get_pcpu(dev);
 168                 if (cpu_est_clockrate(pc->pc_cpuid, &rate) == 0)
 169                         sc->max_mhz = rate / 1000000;
 170                 else
 171                         sc->max_mhz = CPUFREQ_VAL_UNKNOWN;
 172         }
 173
 174         /*
 175          * Only initialize one set of sysctls for all CPUs.  In the future,
 176          * if multiple CPUs can have different settings, we can move these
 177          * sysctls to be under every CPU instead of just the first one.
 178          */
 179         numdevs = devclass_get_count(cpufreq_dc);
 180         if (numdevs > 1)
 181                 return (0);
 182
 183         CF_DEBUG("initializing one-time data for %s\n",
 184             device_get_nameunit(dev));
 185         sc->levels_buf = malloc(CF_MAX_LEVELS * sizeof(*sc->levels_buf),
 186             M_DEVBUF, M_WAITOK);
 187         SYSCTL_ADD_PROC(&sc->sysctl_ctx,
 188             SYSCTL_CHILDREN(device_get_sysctl_tree(parent)),
 189             OID_AUTO, "freq", CTLTYPE_INT | CTLFLAG_RW, sc, 0,
 190             cpufreq_curr_sysctl, "I", "Current CPU frequency");
 191         SYSCTL_ADD_PROC(&sc->sysctl_ctx,
 192             SYSCTL_CHILDREN(device_get_sysctl_tree(parent)),
 193             OID_AUTO, "freq_levels", CTLTYPE_STRING | CTLFLAG_RD, sc, 0,
 194             cpufreq_levels_sysctl, "A", "CPU frequency levels");
 195
 196         /*
 197          * Queue a one-shot broadcast that levels have changed.
 198          * It will run once the system has completed booting.
 199          */
 200         TASK_INIT(&sc->startup_task, 0, cpufreq_startup_task, dev);
 201         taskqueue_enqueue(taskqueue_thread, &sc->startup_task);
 202
 203         return (0);
 204 }
 205
 206 /* Handle any work to be done for all drivers that attached during boot. */
 207 static void
 208 cpufreq_startup_task(void *ctx, int pending)
 209 {
 210
 211         cpufreq_settings_changed((device_t)ctx);
 212 }
 213
 214 static int
 215 cpufreq_detach(device_t dev)
 216 {
 217         struct cpufreq_softc *sc;
 218         struct cf_saved_freq *saved_freq;
 219         int numdevs;
 220
 221         CF_DEBUG("shutdown %s\n", device_get_nameunit(dev));
 222         sc = device_get_softc(dev);
 223         sysctl_ctx_free(&sc->sysctl_ctx);
 224
 225         while ((saved_freq = SLIST_FIRST(&sc->saved_freq)) != NULL) {
 226                 SLIST_REMOVE_HEAD(&sc->saved_freq, link);
 227                 free(saved_freq, M_TEMP);
 228         }
 229
 230         /* Only clean up these resources when the last device is detaching. */
 231         numdevs = devclass_get_count(cpufreq_dc);
 232         if (numdevs == 1) {
 233                 CF_DEBUG("final shutdown for %s\n", device_get_nameunit(dev));
 234                 free(sc->levels_buf, M_DEVBUF);
 235         }
 236
 237         return (0);
 238 }
 239
 240 static int
 241 cf_set_method(device_t dev, const struct cf_level *level, int priority)
 242 {
 243         struct cpufreq_softc *sc;
 244         const struct cf_setting *set;
 245         struct cf_saved_freq *saved_freq, *curr_freq;
 246         struct pcpu *pc;
 247         int error, i;
 248
 249         sc = device_get_softc(dev);
 250         error = 0;
 251         set = NULL;
 252         saved_freq = NULL;
 253
 254         /* We are going to change levels so notify the pre-change handler. */
 255         EVENTHANDLER_INVOKE(cpufreq_pre_change, level, &error);
 256         if (error != 0) {
 257                 EVENTHANDLER_INVOKE(cpufreq_post_change, level, error);
 258                 return (error);
 259         }
 260
 261         CF_MTX_LOCK(&sc->lock);
 262
 263 #ifdef SMP
 264 #ifdef EARLY_AP_STARTUP
 265         MPASS(mp_ncpus == 1 || smp_started);
 266 #else
 267         /*
 268          * If still booting and secondary CPUs not started yet, don't allow
 269          * changing the frequency until they're online.  This is because we
 270          * can't switch to them using sched_bind() and thus we'd only be
 271          * switching the main CPU.  XXXTODO: Need to think more about how to
 272          * handle having different CPUs at different frequencies.
 273          */
 274         if (mp_ncpus > 1 && !smp_started) {
 275                 device_printf(dev, "rejecting change, SMP not started yet\n");
 276                 error = ENXIO;
 277                 goto out;
 278         }
 279 #endif
 280 #endif /* SMP */
 281
 282         /*
 283          * If the requested level has a lower priority, don't allow
 284          * the new level right now.
 285          */
 286         if (priority < sc->curr_priority) {
 287                 CF_DEBUG("ignoring, curr prio %d less than %d\n", priority,
 288                     sc->curr_priority);
 289                 error = EPERM;
 290                 goto out;
 291         }
 292
 293         /*
 294          * If the caller didn't specify a level and one is saved, prepare to
 295          * restore the saved level.  If none has been saved, return an error.
 296          */
 297         if (level == NULL) {
 298                 saved_freq = SLIST_FIRST(&sc->saved_freq);
 299                 if (saved_freq == NULL) {
 300                         CF_DEBUG("NULL level, no saved level\n");
 301                         error = ENXIO;
 302                         goto out;
 303                 }
 304                 level = &saved_freq->level;
 305                 priority = saved_freq->priority;
 306                 CF_DEBUG("restoring saved level, freq %d prio %d\n",
 307                     level->total_set.freq, priority);
 308         }
 309
 310         /* Reject levels that are below our specified threshold. */
 311         if (level->total_set.freq < cf_lowest_freq) {
 312                 CF_DEBUG("rejecting freq %d, less than %d limit\n",
 313                     level->total_set.freq, cf_lowest_freq);
 314                 error = EINVAL;
 315                 goto out;
 316         }
 317
 318         /* If already at this level, just return. */
 319         if (sc->curr_level.total_set.freq == level->total_set.freq) {
 320                 CF_DEBUG("skipping freq %d, same as current level %d\n",
 321                     level->total_set.freq, sc->curr_level.total_set.freq);
 322                 goto skip;
 323         }
 324
 325         /* First, set the absolute frequency via its driver. */
 326         set = &level->abs_set;
 327         if (set->dev) {
 328                 if (!device_is_attached(set->dev)) {
 329                         error = ENXIO;
 330                         goto out;
 331                 }
 332
 333                 /* Bind to the target CPU before switching. */
 334                 pc = cpu_get_pcpu(set->dev);
 335                 thread_lock(curthread);
 336                 sched_bind(curthread, pc->pc_cpuid);
 337                 thread_unlock(curthread);
 338                 CF_DEBUG("setting abs freq %d on %s (cpu %d)\n", set->freq,
 339                     device_get_nameunit(set->dev), PCPU_GET(cpuid));
 340                 error = CPUFREQ_DRV_SET(set->dev, set);
 341                 thread_lock(curthread);
 342                 sched_unbind(curthread);
 343                 thread_unlock(curthread);
 344                 if (error) {
 345                         goto out;
 346                 }
 347         }
 348
 349         /* Next, set any/all relative frequencies via their drivers. */
 350         for (i = 0; i < level->rel_count; i++) {
 351                 set = &level->rel_set[i];
 352                 if (!device_is_attached(set->dev)) {
 353                         error = ENXIO;
 354                         goto out;
 355                 }
 356
 357                 /* Bind to the target CPU before switching. */
 358                 pc = cpu_get_pcpu(set->dev);
 359                 thread_lock(curthread);
 360                 sched_bind(curthread, pc->pc_cpuid);
 361                 thread_unlock(curthread);
 362                 CF_DEBUG("setting rel freq %d on %s (cpu %d)\n", set->freq,
 363                     device_get_nameunit(set->dev), PCPU_GET(cpuid));
 364                 error = CPUFREQ_DRV_SET(set->dev, set);
 365                 thread_lock(curthread);
 366                 sched_unbind(curthread);
 367                 thread_unlock(curthread);
 368                 if (error) {
 369                         /* XXX Back out any successful setting? */
 370                         goto out;
 371                 }
 372         }
 373
 374 skip:
 375         /*
 376          * Before recording the current level, check if we're going to a
 377          * higher priority.  If so, save the previous level and priority.
 378          */
 379         if (sc->curr_level.total_set.freq != CPUFREQ_VAL_UNKNOWN &&
 380             priority > sc->curr_priority) {
 381                 CF_DEBUG("saving level, freq %d prio %d\n",
 382                     sc->curr_level.total_set.freq, sc->curr_priority);
 383                 curr_freq = malloc(sizeof(*curr_freq), M_TEMP, M_NOWAIT);
 384                 if (curr_freq == NULL) {
 385                         error = ENOMEM;
 386                         goto out;
 387                 }
 388                 curr_freq->level = sc->curr_level;
 389                 curr_freq->priority = sc->curr_priority;
 390                 SLIST_INSERT_HEAD(&sc->saved_freq, curr_freq, link);
 391         }
 392         sc->curr_level = *level;
 393         sc->curr_priority = priority;
 394
 395         /* If we were restoring a saved state, reset it to "unused". */
 396         if (saved_freq != NULL) {
 397                 CF_DEBUG("resetting saved level\n");
 398                 sc->curr_level.total_set.freq = CPUFREQ_VAL_UNKNOWN;
 399                 SLIST_REMOVE_HEAD(&sc->saved_freq, link);
 400                 free(saved_freq, M_TEMP);
 401         }
 402
 403 out:
 404         CF_MTX_UNLOCK(&sc->lock);
 405
 406         /*
 407          * We changed levels (or attempted to) so notify the post-change
 408          * handler of new frequency or error.
 409          */
 410         EVENTHANDLER_INVOKE(cpufreq_post_change, level, error);
 411         if (error && set)
 412                 device_printf(set->dev, "set freq failed, err %d\n", error);
 413
 414         return (error);
 415 }
 416
 417 static int
 418 cf_get_method(device_t dev, struct cf_level *level)
 419 {
 420         struct cpufreq_softc *sc;
 421         struct cf_level *levels;
 422         struct cf_setting *curr_set, set;
 423         struct pcpu *pc;
 424         device_t *devs;
 425         int bdiff, count, diff, error, i, n, numdevs;
 426         uint64_t rate;
 427
 428         sc = device_get_softc(dev);
 429         error = 0;
 430         levels = NULL;
 431
 432         /* If we already know the current frequency, we're done. */
 433         CF_MTX_LOCK(&sc->lock);
 434         curr_set = &sc->curr_level.total_set;
 435         if (curr_set->freq != CPUFREQ_VAL_UNKNOWN) {
 436                 CF_DEBUG("get returning known freq %d\n", curr_set->freq);
 437                 goto out;
 438         }
 439         CF_MTX_UNLOCK(&sc->lock);
 440
 441         /*
 442          * We need to figure out the current level.  Loop through every
 443          * driver, getting the current setting.  Then, attempt to get a best
 444          * match of settings against each level.
 445          */
 446         count = CF_MAX_LEVELS;
 447         levels = malloc(count * sizeof(*levels), M_TEMP, M_NOWAIT);
 448         if (levels == NULL)
 449                 return (ENOMEM);
 450         error = CPUFREQ_LEVELS(sc->dev, levels, &count);
 451         if (error) {
 452                 if (error == E2BIG)
 453                         printf("cpufreq: need to increase CF_MAX_LEVELS\n");
 454                 free(levels, M_TEMP);
 455                 return (error);
 456         }
 457         error = device_get_children(device_get_parent(dev), &devs, &numdevs);
 458         if (error) {
 459                 free(levels, M_TEMP);
 460                 return (error);
 461         }
 462
 463         /*
 464          * Reacquire the lock and search for the given level.
 465          *
 466          * XXX Note: this is not quite right since we really need to go
 467          * through each level and compare both absolute and relative
 468          * settings for each driver in the system before making a match.
 469          * The estimation code below catches this case though.
 470          */
 471         CF_MTX_LOCK(&sc->lock);
 472         for (n = 0; n < numdevs && curr_set->freq == CPUFREQ_VAL_UNKNOWN; n++) {
 473                 if (!device_is_attached(devs[n]))
 474                         continue;
 475                 if (CPUFREQ_DRV_GET(devs[n], &set) != 0)
 476                         continue;
 477                 for (i = 0; i < count; i++) {
 478                         if (set.freq == levels[i].total_set.freq) {
 479                                 sc->curr_level = levels[i];
 480                                 break;
 481                         }
 482                 }
 483         }
 484         free(devs, M_TEMP);
 485         if (curr_set->freq != CPUFREQ_VAL_UNKNOWN) {
 486                 CF_DEBUG("get matched freq %d from drivers\n", curr_set->freq);
 487                 goto out;
 488         }
 489
 490         /*
 491          * We couldn't find an exact match, so attempt to estimate and then
 492          * match against a level.
 493          */
 494         pc = cpu_get_pcpu(dev);
 495         if (pc == NULL) {
 496                 error = ENXIO;
 497                 goto out;
 498         }
 499         cpu_est_clockrate(pc->pc_cpuid, &rate);
 500         rate /= 1000000;
 501         bdiff = 1 << 30;
 502         for (i = 0; i < count; i++) {
 503                 diff = abs(levels[i].total_set.freq - rate);
 504                 if (diff < bdiff) {
 505                         bdiff = diff;
 506                         sc->curr_level = levels[i];
 507                 }
 508         }
 509         CF_DEBUG("get estimated freq %d\n", curr_set->freq);
 510
 511 out:
 512         if (error == 0)
 513                 *level = sc->curr_level;
 514
 515         CF_MTX_UNLOCK(&sc->lock);
 516         if (levels)
 517                 free(levels, M_TEMP);
 518         return (error);
 519 }
 520
 521 static int
 522 cf_levels_method(device_t dev, struct cf_level *levels, int *count)
 523 {
 524         struct cf_setting_array *set_arr;
 525         struct cf_setting_lst rel_sets;
 526         struct cpufreq_softc *sc;
 527         struct cf_level *lev;
 528         struct cf_setting *sets;
 529         struct pcpu *pc;
 530         device_t *devs;
 531         int error, i, numdevs, set_count, type;
 532         uint64_t rate;
 533
 534         if (levels == NULL || count == NULL)
 535                 return (EINVAL);
 536
 537         TAILQ_INIT(&rel_sets);
 538         sc = device_get_softc(dev);
 539         error = device_get_children(device_get_parent(dev), &devs, &numdevs);
 540         if (error)
 541                 return (error);
 542         sets = malloc(MAX_SETTINGS * sizeof(*sets), M_TEMP, M_NOWAIT);
 543         if (sets == NULL) {
 544                 free(devs, M_TEMP);
 545                 return (ENOMEM);
 546         }
 547
 548         /* Get settings from all cpufreq drivers. */
 549         CF_MTX_LOCK(&sc->lock);
 550         for (i = 0; i < numdevs; i++) {
 551                 /* Skip devices that aren't ready. */
 552                 if (!device_is_attached(devs[i]))
 553                         continue;
 554
 555                 /*
 556                  * Get settings, skipping drivers that offer no settings or
 557                  * provide settings for informational purposes only.
 558                  */
 559                 error = CPUFREQ_DRV_TYPE(devs[i], &type);
 560                 if (error || (type & CPUFREQ_FLAG_INFO_ONLY)) {
 561                         if (error == 0) {
 562                                 CF_DEBUG("skipping info-only driver %s\n",
 563                                     device_get_nameunit(devs[i]));
 564                         }
 565                         continue;
 566                 }
 567                 set_count = MAX_SETTINGS;
 568                 error = CPUFREQ_DRV_SETTINGS(devs[i], sets, &set_count);
 569                 if (error || set_count == 0)
 570                         continue;
 571
 572                 /* Add the settings to our absolute/relative lists. */
 573                 switch (type & CPUFREQ_TYPE_MASK) {
 574                 case CPUFREQ_TYPE_ABSOLUTE:
 575                         error = cpufreq_insert_abs(sc, sets, set_count);
 576                         break;
 577                 case CPUFREQ_TYPE_RELATIVE:
 578                         CF_DEBUG("adding %d relative settings\n", set_count);
 579                         set_arr = malloc(sizeof(*set_arr), M_TEMP, M_NOWAIT);
 580                         if (set_arr == NULL) {
 581                                 error = ENOMEM;
 582                                 goto out;
 583                         }
 584                         bcopy(sets, set_arr->sets, set_count * sizeof(*sets));
 585                         set_arr->count = set_count;
 586                         TAILQ_INSERT_TAIL(&rel_sets, set_arr, link);
 587                         break;
 588                 default:
 589                         error = EINVAL;
 590                 }
 591                 if (error)
 592                         goto out;
 593         }
 594
 595         /*
 596          * If there are no absolute levels, create a fake one at 100%.  We
 597          * then cache the clockrate for later use as our base frequency.
 598          */
 599         if (TAILQ_EMPTY(&sc->all_levels)) {
 600                 if (sc->max_mhz == CPUFREQ_VAL_UNKNOWN) {
 601                         sc->max_mhz = cpu_get_nominal_mhz(dev);
 602                         /*
 603                          * If the CPU can't report a rate for 100%, hope
 604                          * the CPU is running at its nominal rate right now,
 605                          * and use that instead.
 606                          */
 607                         if (sc->max_mhz <= 0) {
 608                                 pc = cpu_get_pcpu(dev);
 609                                 cpu_est_clockrate(pc->pc_cpuid, &rate);
 610                                 sc->max_mhz = rate / 1000000;
 611                         }
 612                 }
 613                 memset(&sets[0], CPUFREQ_VAL_UNKNOWN, sizeof(*sets));
 614                 sets[0].freq = sc->max_mhz;
 615                 sets[0].dev = NULL;
 616                 error = cpufreq_insert_abs(sc, sets, 1);
 617                 if (error)
 618                         goto out;
 619         }
 620
 621         /* Create a combined list of absolute + relative levels. */
 622         TAILQ_FOREACH(set_arr, &rel_sets, link)
 623                 cpufreq_expand_set(sc, set_arr);
 624
 625         /* If the caller doesn't have enough space, return the actual count. */
 626         if (sc->all_count > *count) {
 627                 *count = sc->all_count;
 628                 error = E2BIG;
 629                 goto out;
 630         }
 631
 632         /* Finally, output the list of levels. */
 633         i = 0;
 634         TAILQ_FOREACH(lev, &sc->all_levels, link) {
 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 best, count, diff, bdiff, devcount, error, freq, i, n;
 869         device_t *devs;
 870
 871         devs = NULL;
 872         sc = oidp->oid_arg1;
 873         levels = sc->levels_buf;
 874
 875         error = CPUFREQ_GET(sc->dev, &levels[0]);
 876         if (error)
 877                 goto out;
 878         freq = levels[0].total_set.freq;
 879         error = sysctl_handle_int(oidp, &freq, 0, req);
 880         if (error != 0 || req->newptr == NULL)
 881                 goto out;
 882
 883         /*
 884          * While we only call cpufreq_get() on one device (assuming all
 885          * CPUs have equal levels), we call cpufreq_set() on all CPUs.
 886          * This is needed for some MP systems.
 887          */
 888         error = devclass_get_devices(cpufreq_dc, &devs, &devcount);
 889         if (error)
 890                 goto out;
 891         for (n = 0; n < devcount; n++) {
 892                 count = CF_MAX_LEVELS;
 893                 error = CPUFREQ_LEVELS(devs[n], levels, &count);
 894                 if (error) {
 895                         if (error == E2BIG)
 896                                 printf(
 897                         "cpufreq: need to increase CF_MAX_LEVELS\n");
 898                         break;
 899                 }
 900                 best = 0;
 901                 bdiff = 1 << 30;
 902                 for (i = 0; i < count; i++) {
 903                         diff = abs(levels[i].total_set.freq - freq);
 904                         if (diff < bdiff) {
 905                                 bdiff = diff;
 906                                 best = i;
 907                         }
 908                 }
 909                 error = CPUFREQ_SET(devs[n], &levels[best], CPUFREQ_PRIO_USER);
 910         }
 911
 912 out:
 913         if (devs)
 914                 free(devs, M_TEMP);
 915         return (error);
 916 }
 917
 918 static int
 919 cpufreq_levels_sysctl(SYSCTL_HANDLER_ARGS)
 920 {
 921         struct cpufreq_softc *sc;
 922         struct cf_level *levels;
 923         struct cf_setting *set;
 924         struct sbuf sb;
 925         int count, error, i;
 926
 927         sc = oidp->oid_arg1;
 928         sbuf_new(&sb, NULL, 128, SBUF_AUTOEXTEND);
 929
 930         /* Get settings from the device and generate the output string. */
 931         count = CF_MAX_LEVELS;
 932         levels = sc->levels_buf;
 933         if (levels == NULL) {
 934                 sbuf_delete(&sb);
 935                 return (ENOMEM);
 936         }
 937         error = CPUFREQ_LEVELS(sc->dev, levels, &count);
 938         if (error) {
 939                 if (error == E2BIG)
 940                         printf("cpufreq: need to increase CF_MAX_LEVELS\n");
 941                 goto out;
 942         }
 943         if (count) {
 944                 for (i = 0; i < count; i++) {
 945                         set = &levels[i].total_set;
 946                         sbuf_printf(&sb, "%d/%d ", set->freq, set->power);
 947                 }
 948         } else
 949                 sbuf_cpy(&sb, "0");
 950         sbuf_trim(&sb);
 951         sbuf_finish(&sb);
 952         error = sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req);
 953
 954 out:
 955         sbuf_delete(&sb);
 956         return (error);
 957 }
 958
 959 static int
 960 cpufreq_settings_sysctl(SYSCTL_HANDLER_ARGS)
 961 {
 962         device_t dev;
 963         struct cf_setting *sets;
 964         struct sbuf sb;
 965         int error, i, set_count;
 966
 967         dev = oidp->oid_arg1;
 968         sbuf_new(&sb, NULL, 128, SBUF_AUTOEXTEND);
 969
 970         /* Get settings from the device and generate the output string. */
 971         set_count = MAX_SETTINGS;
 972         sets = malloc(set_count * sizeof(*sets), M_TEMP, M_NOWAIT);
 973         if (sets == NULL) {
 974                 sbuf_delete(&sb);
 975                 return (ENOMEM);
 976         }
 977         error = CPUFREQ_DRV_SETTINGS(dev, sets, &set_count);
 978         if (error)
 979                 goto out;
 980         if (set_count) {
 981                 for (i = 0; i < set_count; i++)
 982                         sbuf_printf(&sb, "%d/%d ", sets[i].freq, sets[i].power);
 983         } else
 984                 sbuf_cpy(&sb, "0");
 985         sbuf_trim(&sb);
 986         sbuf_finish(&sb);
 987         error = sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req);
 988
 989 out:
 990         free(sets, M_TEMP);
 991         sbuf_delete(&sb);
 992         return (error);
 993 }
 994
 995 int
 996 cpufreq_register(device_t dev)
 997 {
 998         struct cpufreq_softc *sc;
 999         device_t cf_dev, cpu_dev;
1000
1001         /* Add a sysctl to get each driver's settings separately. */
1002         SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
1003             SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
1004             OID_AUTO, "freq_settings", CTLTYPE_STRING | CTLFLAG_RD, dev, 0,
1005             cpufreq_settings_sysctl, "A", "CPU frequency driver settings");
1006
1007         /*
1008          * Add only one cpufreq device to each CPU.  Currently, all CPUs
1009          * must offer the same levels and be switched at the same time.
1010          */
1011         cpu_dev = device_get_parent(dev);
1012         if ((cf_dev = device_find_child(cpu_dev, "cpufreq", -1))) {
1013                 sc = device_get_softc(cf_dev);
1014                 sc->max_mhz = CPUFREQ_VAL_UNKNOWN;
1015                 return (0);
1016         }
1017
1018         /* Add the child device and possibly sysctls. */
1019         cf_dev = BUS_ADD_CHILD(cpu_dev, 0, "cpufreq", -1);
1020         if (cf_dev == NULL)
1021                 return (ENOMEM);
1022         device_quiet(cf_dev);
1023
1024         return (device_probe_and_attach(cf_dev));
1025 }
1026
1027 int
1028 cpufreq_unregister(device_t dev)
1029 {
1030         device_t cf_dev, *devs;
1031         int cfcount, devcount, error, i, type;
1032
1033         /*
1034          * If this is the last cpufreq child device, remove the control
1035          * device as well.  We identify cpufreq children by calling a method
1036          * they support.
1037          */
1038         error = device_get_children(device_get_parent(dev), &devs, &devcount);
1039         if (error)
1040                 return (error);
1041         cf_dev = device_find_child(device_get_parent(dev), "cpufreq", -1);
1042         if (cf_dev == NULL) {
1043                 device_printf(dev,
1044         "warning: cpufreq_unregister called with no cpufreq device active\n");
1045                 free(devs, M_TEMP);
1046                 return (0);
1047         }
1048         cfcount = 0;
1049         for (i = 0; i < devcount; i++) {
1050                 if (!device_is_attached(devs[i]))
1051                         continue;
1052                 if (CPUFREQ_DRV_TYPE(devs[i], &type) == 0)
1053                         cfcount++;
1054         }
1055         if (cfcount <= 1)
1056                 device_delete_child(device_get_parent(cf_dev), cf_dev);
1057         free(devs, M_TEMP);
1058
1059         return (0);
1060 }
1061
1062 int
1063 cpufreq_settings_changed(device_t dev)
1064 {
1065
1066         EVENTHANDLER_INVOKE(cpufreq_levels_changed,
1067             device_get_unit(device_get_parent(dev)));
1068         return (0);
1069 }