The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_cpu.c

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    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: releng/8.1/sys/kern/kern_cpu.c 202815 2010-01-22 17:03:49Z brueffer $");
   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, "");
  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, "");
  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 }

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