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/7.3/sys/kern/kern_cpu.c 202816 2010-01-22 17:08:05Z 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 current CPU freq to use it as maximum later if needed */
  162         pc = cpu_get_pcpu(dev);
  163         if (cpu_est_clockrate(pc->pc_cpuid, &rate) == 0)
  164                 sc->max_mhz = rate / 1000000;
  165         else
  166                 sc->max_mhz = CPUFREQ_VAL_UNKNOWN;
  167 
  168         /*
  169          * Only initialize one set of sysctls for all CPUs.  In the future,
  170          * if multiple CPUs can have different settings, we can move these
  171          * sysctls to be under every CPU instead of just the first one.
  172          */
  173         numdevs = devclass_get_count(cpufreq_dc);
  174         if (numdevs > 1)
  175                 return (0);
  176 
  177         CF_DEBUG("initializing one-time data for %s\n",
  178             device_get_nameunit(dev));
  179         SYSCTL_ADD_PROC(&sc->sysctl_ctx,
  180             SYSCTL_CHILDREN(device_get_sysctl_tree(parent)),
  181             OID_AUTO, "freq", CTLTYPE_INT | CTLFLAG_RW, sc, 0,
  182             cpufreq_curr_sysctl, "I", "Current CPU frequency");
  183         SYSCTL_ADD_PROC(&sc->sysctl_ctx,
  184             SYSCTL_CHILDREN(device_get_sysctl_tree(parent)),
  185             OID_AUTO, "freq_levels", CTLTYPE_STRING | CTLFLAG_RD, sc, 0,
  186             cpufreq_levels_sysctl, "A", "CPU frequency levels");
  187 
  188         /*
  189          * Queue a one-shot broadcast that levels have changed.
  190          * It will run once the system has completed booting.
  191          */
  192         TASK_INIT(&sc->startup_task, 0, cpufreq_startup_task, dev);
  193         taskqueue_enqueue(taskqueue_thread, &sc->startup_task);
  194 
  195         return (0);
  196 }
  197 
  198 /* Handle any work to be done for all drivers that attached during boot. */
  199 static void 
  200 cpufreq_startup_task(void *ctx, int pending)
  201 {
  202 
  203         cpufreq_settings_changed((device_t)ctx);
  204 }
  205 
  206 static int
  207 cpufreq_detach(device_t dev)
  208 {
  209         struct cpufreq_softc *sc;
  210         struct cf_saved_freq *saved_freq;
  211         int numdevs;
  212 
  213         CF_DEBUG("shutdown %s\n", device_get_nameunit(dev));
  214         sc = device_get_softc(dev);
  215         sysctl_ctx_free(&sc->sysctl_ctx);
  216 
  217         while ((saved_freq = SLIST_FIRST(&sc->saved_freq)) != NULL) {
  218                 SLIST_REMOVE_HEAD(&sc->saved_freq, link);
  219                 free(saved_freq, M_TEMP);
  220         }
  221 
  222         /* Only clean up these resources when the last device is detaching. */
  223         numdevs = devclass_get_count(cpufreq_dc);
  224         if (numdevs == 1) {
  225                 CF_DEBUG("final shutdown for %s\n", device_get_nameunit(dev));
  226         }
  227 
  228         return (0);
  229 }
  230 
  231 static int
  232 cf_set_method(device_t dev, const struct cf_level *level, int priority)
  233 {
  234         struct cpufreq_softc *sc;
  235         const struct cf_setting *set;
  236         struct cf_saved_freq *saved_freq, *curr_freq;
  237         struct pcpu *pc;
  238         int error, i;
  239 
  240         sc = device_get_softc(dev);
  241         error = 0;
  242         set = NULL;
  243         saved_freq = NULL;
  244 
  245         /* We are going to change levels so notify the pre-change handler. */
  246         EVENTHANDLER_INVOKE(cpufreq_pre_change, level, &error);
  247         if (error != 0) {
  248                 EVENTHANDLER_INVOKE(cpufreq_post_change, level, error);
  249                 return (error);
  250         }
  251 
  252         CF_MTX_LOCK(&sc->lock);
  253 
  254 #ifdef SMP
  255         /*
  256          * If still booting and secondary CPUs not started yet, don't allow
  257          * changing the frequency until they're online.  This is because we
  258          * can't switch to them using sched_bind() and thus we'd only be
  259          * switching the main CPU.  XXXTODO: Need to think more about how to
  260          * handle having different CPUs at different frequencies.  
  261          */
  262         if (mp_ncpus > 1 && !smp_active) {
  263                 device_printf(dev, "rejecting change, SMP not started yet\n");
  264                 error = ENXIO;
  265                 goto out;
  266         }
  267 #endif /* SMP */
  268 
  269         /*
  270          * If the requested level has a lower priority, don't allow
  271          * the new level right now.
  272          */
  273         if (priority < sc->curr_priority) {
  274                 CF_DEBUG("ignoring, curr prio %d less than %d\n", priority,
  275                     sc->curr_priority);
  276                 error = EPERM;
  277                 goto out;
  278         }
  279 
  280         /*
  281          * If the caller didn't specify a level and one is saved, prepare to
  282          * restore the saved level.  If none has been saved, return an error.
  283          */
  284         if (level == NULL) {
  285                 saved_freq = SLIST_FIRST(&sc->saved_freq);
  286                 if (saved_freq == NULL) {
  287                         CF_DEBUG("NULL level, no saved level\n");
  288                         error = ENXIO;
  289                         goto out;
  290                 }
  291                 level = &saved_freq->level;
  292                 priority = saved_freq->priority;
  293                 CF_DEBUG("restoring saved level, freq %d prio %d\n",
  294                     level->total_set.freq, priority);
  295         }
  296 
  297         /* Reject levels that are below our specified threshold. */
  298         if (level->total_set.freq < cf_lowest_freq) {
  299                 CF_DEBUG("rejecting freq %d, less than %d limit\n",
  300                     level->total_set.freq, cf_lowest_freq);
  301                 error = EINVAL;
  302                 goto out;
  303         }
  304 
  305         /* If already at this level, just return. */
  306         if (CPUFREQ_CMP(sc->curr_level.total_set.freq, level->total_set.freq)) {
  307                 CF_DEBUG("skipping freq %d, same as current level %d\n",
  308                     level->total_set.freq, sc->curr_level.total_set.freq);
  309                 goto skip;
  310         }
  311 
  312         /* First, set the absolute frequency via its driver. */
  313         set = &level->abs_set;
  314         if (set->dev) {
  315                 if (!device_is_attached(set->dev)) {
  316                         error = ENXIO;
  317                         goto out;
  318                 }
  319 
  320                 /* Bind to the target CPU before switching. */
  321                 pc = cpu_get_pcpu(set->dev);
  322                 thread_lock(curthread);
  323                 sched_bind(curthread, pc->pc_cpuid);
  324                 thread_unlock(curthread);
  325                 CF_DEBUG("setting abs freq %d on %s (cpu %d)\n", set->freq,
  326                     device_get_nameunit(set->dev), PCPU_GET(cpuid));
  327                 error = CPUFREQ_DRV_SET(set->dev, set);
  328                 thread_lock(curthread);
  329                 sched_unbind(curthread);
  330                 thread_unlock(curthread);
  331                 if (error) {
  332                         goto out;
  333                 }
  334         }
  335 
  336         /* Next, set any/all relative frequencies via their drivers. */
  337         for (i = 0; i < level->rel_count; i++) {
  338                 set = &level->rel_set[i];
  339                 if (!device_is_attached(set->dev)) {
  340                         error = ENXIO;
  341                         goto out;
  342                 }
  343 
  344                 /* Bind to the target CPU before switching. */
  345                 pc = cpu_get_pcpu(set->dev);
  346                 thread_lock(curthread);
  347                 sched_bind(curthread, pc->pc_cpuid);
  348                 thread_unlock(curthread);
  349                 CF_DEBUG("setting rel freq %d on %s (cpu %d)\n", set->freq,
  350                     device_get_nameunit(set->dev), PCPU_GET(cpuid));
  351                 error = CPUFREQ_DRV_SET(set->dev, set);
  352                 thread_lock(curthread);
  353                 sched_unbind(curthread);
  354                 thread_unlock(curthread);
  355                 if (error) {
  356                         /* XXX Back out any successful setting? */
  357                         goto out;
  358                 }
  359         }
  360 
  361 skip:
  362         /*
  363          * Before recording the current level, check if we're going to a
  364          * higher priority.  If so, save the previous level and priority.
  365          */
  366         if (sc->curr_level.total_set.freq != CPUFREQ_VAL_UNKNOWN &&
  367             priority > sc->curr_priority) {
  368                 CF_DEBUG("saving level, freq %d prio %d\n",
  369                     sc->curr_level.total_set.freq, sc->curr_priority);
  370                 curr_freq = malloc(sizeof(*curr_freq), M_TEMP, M_NOWAIT);
  371                 if (curr_freq == NULL) {
  372                         error = ENOMEM;
  373                         goto out;
  374                 }
  375                 curr_freq->level = sc->curr_level;
  376                 curr_freq->priority = sc->curr_priority;
  377                 SLIST_INSERT_HEAD(&sc->saved_freq, curr_freq, link);
  378         }
  379         sc->curr_level = *level;
  380         sc->curr_priority = priority;
  381 
  382         /* If we were restoring a saved state, reset it to "unused". */
  383         if (saved_freq != NULL) {
  384                 CF_DEBUG("resetting saved level\n");
  385                 sc->curr_level.total_set.freq = CPUFREQ_VAL_UNKNOWN;
  386                 SLIST_REMOVE_HEAD(&sc->saved_freq, link);
  387                 free(saved_freq, M_TEMP);
  388         }
  389 
  390 out:
  391         CF_MTX_UNLOCK(&sc->lock);
  392 
  393         /*
  394          * We changed levels (or attempted to) so notify the post-change
  395          * handler of new frequency or error.
  396          */
  397         EVENTHANDLER_INVOKE(cpufreq_post_change, level, error);
  398         if (error && set)
  399                 device_printf(set->dev, "set freq failed, err %d\n", error);
  400 
  401         return (error);
  402 }
  403 
  404 static int
  405 cf_get_method(device_t dev, struct cf_level *level)
  406 {
  407         struct cpufreq_softc *sc;
  408         struct cf_level *levels;
  409         struct cf_setting *curr_set, set;
  410         struct pcpu *pc;
  411         device_t *devs;
  412         int count, error, i, n, numdevs;
  413         uint64_t rate;
  414 
  415         sc = device_get_softc(dev);
  416         error = 0;
  417         levels = NULL;
  418 
  419         /* If we already know the current frequency, we're done. */
  420         CF_MTX_LOCK(&sc->lock);
  421         curr_set = &sc->curr_level.total_set;
  422         if (curr_set->freq != CPUFREQ_VAL_UNKNOWN) {
  423                 CF_DEBUG("get returning known freq %d\n", curr_set->freq);
  424                 goto out;
  425         }
  426         CF_MTX_UNLOCK(&sc->lock);
  427 
  428         /*
  429          * We need to figure out the current level.  Loop through every
  430          * driver, getting the current setting.  Then, attempt to get a best
  431          * match of settings against each level.
  432          */
  433         count = CF_MAX_LEVELS;
  434         levels = malloc(count * sizeof(*levels), M_TEMP, M_NOWAIT);
  435         if (levels == NULL)
  436                 return (ENOMEM);
  437         error = CPUFREQ_LEVELS(sc->dev, levels, &count);
  438         if (error) {
  439                 if (error == E2BIG)
  440                         printf("cpufreq: need to increase CF_MAX_LEVELS\n");
  441                 free(levels, M_TEMP);
  442                 return (error);
  443         }
  444         error = device_get_children(device_get_parent(dev), &devs, &numdevs);
  445         if (error) {
  446                 free(levels, M_TEMP);
  447                 return (error);
  448         }
  449 
  450         /*
  451          * Reacquire the lock and search for the given level.
  452          *
  453          * XXX Note: this is not quite right since we really need to go
  454          * through each level and compare both absolute and relative
  455          * settings for each driver in the system before making a match.
  456          * The estimation code below catches this case though.
  457          */
  458         CF_MTX_LOCK(&sc->lock);
  459         for (n = 0; n < numdevs && curr_set->freq == CPUFREQ_VAL_UNKNOWN; n++) {
  460                 if (!device_is_attached(devs[n]))
  461                         continue;
  462                 if (CPUFREQ_DRV_GET(devs[n], &set) != 0)
  463                         continue;
  464                 for (i = 0; i < count; i++) {
  465                         if (CPUFREQ_CMP(set.freq, levels[i].total_set.freq)) {
  466                                 sc->curr_level = levels[i];
  467                                 break;
  468                         }
  469                 }
  470         }
  471         free(devs, M_TEMP);
  472         if (curr_set->freq != CPUFREQ_VAL_UNKNOWN) {
  473                 CF_DEBUG("get matched freq %d from drivers\n", curr_set->freq);
  474                 goto out;
  475         }
  476 
  477         /*
  478          * We couldn't find an exact match, so attempt to estimate and then
  479          * match against a level.
  480          */
  481         pc = cpu_get_pcpu(dev);
  482         if (pc == NULL) {
  483                 error = ENXIO;
  484                 goto out;
  485         }
  486         cpu_est_clockrate(pc->pc_cpuid, &rate);
  487         rate /= 1000000;
  488         for (i = 0; i < count; i++) {
  489                 if (CPUFREQ_CMP(rate, levels[i].total_set.freq)) {
  490                         sc->curr_level = levels[i];
  491                         CF_DEBUG("get estimated freq %d\n", curr_set->freq);
  492                         goto out;
  493                 }
  494         }
  495         error = ENXIO;
  496 
  497 out:
  498         if (error == 0)
  499                 *level = sc->curr_level;
  500 
  501         CF_MTX_UNLOCK(&sc->lock);
  502         if (levels)
  503                 free(levels, M_TEMP);
  504         return (error);
  505 }
  506 
  507 static int
  508 cf_levels_method(device_t dev, struct cf_level *levels, int *count)
  509 {
  510         struct cf_setting_array *set_arr;
  511         struct cf_setting_lst rel_sets;
  512         struct cpufreq_softc *sc;
  513         struct cf_level *lev;
  514         struct cf_setting *sets;
  515         struct pcpu *pc;
  516         device_t *devs;
  517         int error, i, numdevs, set_count, type;
  518         uint64_t rate;
  519 
  520         if (levels == NULL || count == NULL)
  521                 return (EINVAL);
  522 
  523         TAILQ_INIT(&rel_sets);
  524         sc = device_get_softc(dev);
  525         error = device_get_children(device_get_parent(dev), &devs, &numdevs);
  526         if (error)
  527                 return (error);
  528         sets = malloc(MAX_SETTINGS * sizeof(*sets), M_TEMP, M_NOWAIT);
  529         if (sets == NULL) {
  530                 free(devs, M_TEMP);
  531                 return (ENOMEM);
  532         }
  533 
  534         /* Get settings from all cpufreq drivers. */
  535         CF_MTX_LOCK(&sc->lock);
  536         for (i = 0; i < numdevs; i++) {
  537                 /* Skip devices that aren't ready. */
  538                 if (!device_is_attached(devs[i]))
  539                         continue;
  540 
  541                 /*
  542                  * Get settings, skipping drivers that offer no settings or
  543                  * provide settings for informational purposes only.
  544                  */
  545                 error = CPUFREQ_DRV_TYPE(devs[i], &type);
  546                 if (error || (type & CPUFREQ_FLAG_INFO_ONLY)) {
  547                         if (error == 0) {
  548                                 CF_DEBUG("skipping info-only driver %s\n",
  549                                     device_get_nameunit(devs[i]));
  550                         }
  551                         continue;
  552                 }
  553                 set_count = MAX_SETTINGS;
  554                 error = CPUFREQ_DRV_SETTINGS(devs[i], sets, &set_count);
  555                 if (error || set_count == 0)
  556                         continue;
  557 
  558                 /* Add the settings to our absolute/relative lists. */
  559                 switch (type & CPUFREQ_TYPE_MASK) {
  560                 case CPUFREQ_TYPE_ABSOLUTE:
  561                         error = cpufreq_insert_abs(sc, sets, set_count);
  562                         break;
  563                 case CPUFREQ_TYPE_RELATIVE:
  564                         CF_DEBUG("adding %d relative settings\n", set_count);
  565                         set_arr = malloc(sizeof(*set_arr), M_TEMP, M_NOWAIT);
  566                         if (set_arr == NULL) {
  567                                 error = ENOMEM;
  568                                 goto out;
  569                         }
  570                         bcopy(sets, set_arr->sets, set_count * sizeof(*sets));
  571                         set_arr->count = set_count;
  572                         TAILQ_INSERT_TAIL(&rel_sets, set_arr, link);
  573                         break;
  574                 default:
  575                         error = EINVAL;
  576                 }
  577                 if (error)
  578                         goto out;
  579         }
  580 
  581         /*
  582          * If there are no absolute levels, create a fake one at 100%.  We
  583          * then cache the clockrate for later use as our base frequency.
  584          *
  585          * XXX This assumes that the first time through, if we only have
  586          * relative drivers, the CPU is currently running at 100%.
  587          */
  588         if (TAILQ_EMPTY(&sc->all_levels)) {
  589                 if (sc->max_mhz == CPUFREQ_VAL_UNKNOWN) {
  590                         pc = cpu_get_pcpu(dev);
  591                         cpu_est_clockrate(pc->pc_cpuid, &rate);
  592                         sc->max_mhz = rate / 1000000;
  593                 }
  594                 memset(&sets[0], CPUFREQ_VAL_UNKNOWN, sizeof(*sets));
  595                 sets[0].freq = sc->max_mhz;
  596                 sets[0].dev = NULL;
  597                 error = cpufreq_insert_abs(sc, sets, 1);
  598                 if (error)
  599                         goto out;
  600         }
  601 
  602         /* Create a combined list of absolute + relative levels. */
  603         TAILQ_FOREACH(set_arr, &rel_sets, link)
  604                 cpufreq_expand_set(sc, set_arr);
  605 
  606         /* If the caller doesn't have enough space, return the actual count. */
  607         if (sc->all_count > *count) {
  608                 *count = sc->all_count;
  609                 error = E2BIG;
  610                 goto out;
  611         }
  612 
  613         /* Finally, output the list of levels. */
  614         i = 0;
  615         TAILQ_FOREACH(lev, &sc->all_levels, link) {
  616                 /*
  617                  * Skip levels that are too close in frequency to the
  618                  * previous levels.  Some systems report bogus duplicate
  619                  * settings (i.e., for acpi_perf).
  620                  */
  621                 if (i > 0 && CPUFREQ_CMP(lev->total_set.freq,
  622                     levels[i - 1].total_set.freq)) {
  623                         sc->all_count--;
  624                         continue;
  625                 }
  626 
  627                 /* Skip levels that have a frequency that is too low. */
  628                 if (lev->total_set.freq < cf_lowest_freq) {
  629                         sc->all_count--;
  630                         continue;
  631                 }
  632 
  633                 levels[i] = *lev;
  634                 i++;
  635         }
  636         *count = sc->all_count;
  637         error = 0;
  638 
  639 out:
  640         /* Clear all levels since we regenerate them each time. */
  641         while ((lev = TAILQ_FIRST(&sc->all_levels)) != NULL) {
  642                 TAILQ_REMOVE(&sc->all_levels, lev, link);
  643                 free(lev, M_TEMP);
  644         }
  645         sc->all_count = 0;
  646 
  647         CF_MTX_UNLOCK(&sc->lock);
  648         while ((set_arr = TAILQ_FIRST(&rel_sets)) != NULL) {
  649                 TAILQ_REMOVE(&rel_sets, set_arr, link);
  650                 free(set_arr, M_TEMP);
  651         }
  652         free(devs, M_TEMP);
  653         free(sets, M_TEMP);
  654         return (error);
  655 }
  656 
  657 /*
  658  * Create levels for an array of absolute settings and insert them in
  659  * sorted order in the specified list.
  660  */
  661 static int
  662 cpufreq_insert_abs(struct cpufreq_softc *sc, struct cf_setting *sets,
  663     int count)
  664 {
  665         struct cf_level_lst *list;
  666         struct cf_level *level, *search;
  667         int i;
  668 
  669         CF_MTX_ASSERT(&sc->lock);
  670 
  671         list = &sc->all_levels;
  672         for (i = 0; i < count; i++) {
  673                 level = malloc(sizeof(*level), M_TEMP, M_NOWAIT | M_ZERO);
  674                 if (level == NULL)
  675                         return (ENOMEM);
  676                 level->abs_set = sets[i];
  677                 level->total_set = sets[i];
  678                 level->total_set.dev = NULL;
  679                 sc->all_count++;
  680 
  681                 if (TAILQ_EMPTY(list)) {
  682                         CF_DEBUG("adding abs setting %d at head\n",
  683                             sets[i].freq);
  684                         TAILQ_INSERT_HEAD(list, level, link);
  685                         continue;
  686                 }
  687 
  688                 TAILQ_FOREACH_REVERSE(search, list, cf_level_lst, link) {
  689                         if (sets[i].freq <= search->total_set.freq) {
  690                                 CF_DEBUG("adding abs setting %d after %d\n",
  691                                     sets[i].freq, search->total_set.freq);
  692                                 TAILQ_INSERT_AFTER(list, search, level, link);
  693                                 break;
  694                         }
  695                 }
  696         }
  697         return (0);
  698 }
  699 
  700 /*
  701  * Expand a group of relative settings, creating derived levels from them.
  702  */
  703 static int
  704 cpufreq_expand_set(struct cpufreq_softc *sc, struct cf_setting_array *set_arr)
  705 {
  706         struct cf_level *fill, *search;
  707         struct cf_setting *set;
  708         int i;
  709 
  710         CF_MTX_ASSERT(&sc->lock);
  711 
  712         /*
  713          * Walk the set of all existing levels in reverse.  This is so we
  714          * create derived states from the lowest absolute settings first
  715          * and discard duplicates created from higher absolute settings.
  716          * For instance, a level of 50 Mhz derived from 100 Mhz + 50% is
  717          * preferable to 200 Mhz + 25% because absolute settings are more
  718          * efficient since they often change the voltage as well.
  719          */
  720         TAILQ_FOREACH_REVERSE(search, &sc->all_levels, cf_level_lst, link) {
  721                 /* Add each setting to the level, duplicating if necessary. */
  722                 for (i = 0; i < set_arr->count; i++) {
  723                         set = &set_arr->sets[i];
  724 
  725                         /*
  726                          * If this setting is less than 100%, split the level
  727                          * into two and add this setting to the new level.
  728                          */
  729                         fill = search;
  730                         if (set->freq < 10000) {
  731                                 fill = cpufreq_dup_set(sc, search, set);
  732 
  733                                 /*
  734                                  * The new level was a duplicate of an existing
  735                                  * level or its absolute setting is too high
  736                                  * so we freed it.  For example, we discard a
  737                                  * derived level of 1000 MHz/25% if a level
  738                                  * of 500 MHz/100% already exists.
  739                                  */
  740                                 if (fill == NULL)
  741                                         break;
  742                         }
  743 
  744                         /* Add this setting to the existing or new level. */
  745                         KASSERT(fill->rel_count < MAX_SETTINGS,
  746                             ("cpufreq: too many relative drivers (%d)",
  747                             MAX_SETTINGS));
  748                         fill->rel_set[fill->rel_count] = *set;
  749                         fill->rel_count++;
  750                         CF_DEBUG(
  751                         "expand set added rel setting %d%% to %d level\n",
  752                             set->freq / 100, fill->total_set.freq);
  753                 }
  754         }
  755 
  756         return (0);
  757 }
  758 
  759 static struct cf_level *
  760 cpufreq_dup_set(struct cpufreq_softc *sc, struct cf_level *dup,
  761     struct cf_setting *set)
  762 {
  763         struct cf_level_lst *list;
  764         struct cf_level *fill, *itr;
  765         struct cf_setting *fill_set, *itr_set;
  766         int i;
  767 
  768         CF_MTX_ASSERT(&sc->lock);
  769 
  770         /*
  771          * Create a new level, copy it from the old one, and update the
  772          * total frequency and power by the percentage specified in the
  773          * relative setting.
  774          */
  775         fill = malloc(sizeof(*fill), M_TEMP, M_NOWAIT);
  776         if (fill == NULL)
  777                 return (NULL);
  778         *fill = *dup;
  779         fill_set = &fill->total_set;
  780         fill_set->freq =
  781             ((uint64_t)fill_set->freq * set->freq) / 10000;
  782         if (fill_set->power != CPUFREQ_VAL_UNKNOWN) {
  783                 fill_set->power = ((uint64_t)fill_set->power * set->freq)
  784                     / 10000;
  785         }
  786         if (set->lat != CPUFREQ_VAL_UNKNOWN) {
  787                 if (fill_set->lat != CPUFREQ_VAL_UNKNOWN)
  788                         fill_set->lat += set->lat;
  789                 else
  790                         fill_set->lat = set->lat;
  791         }
  792         CF_DEBUG("dup set considering derived setting %d\n", fill_set->freq);
  793 
  794         /*
  795          * If we copied an old level that we already modified (say, at 100%),
  796          * we need to remove that setting before adding this one.  Since we
  797          * process each setting array in order, we know any settings for this
  798          * driver will be found at the end.
  799          */
  800         for (i = fill->rel_count; i != 0; i--) {
  801                 if (fill->rel_set[i - 1].dev != set->dev)
  802                         break;
  803                 CF_DEBUG("removed last relative driver: %s\n",
  804                     device_get_nameunit(set->dev));
  805                 fill->rel_count--;
  806         }
  807 
  808         /*
  809          * Insert the new level in sorted order.  If it is a duplicate of an
  810          * existing level (1) or has an absolute setting higher than the
  811          * existing level (2), do not add it.  We can do this since any such
  812          * level is guaranteed use less power.  For example (1), a level with
  813          * one absolute setting of 800 Mhz uses less power than one composed
  814          * of an absolute setting of 1600 Mhz and a relative setting at 50%.
  815          * Also for example (2), a level of 800 Mhz/75% is preferable to
  816          * 1600 Mhz/25% even though the latter has a lower total frequency.
  817          */
  818         list = &sc->all_levels;
  819         KASSERT(!TAILQ_EMPTY(list), ("all levels list empty in dup set"));
  820         TAILQ_FOREACH_REVERSE(itr, list, cf_level_lst, link) {
  821                 itr_set = &itr->total_set;
  822                 if (CPUFREQ_CMP(fill_set->freq, itr_set->freq)) {
  823                         CF_DEBUG("dup set rejecting %d (dupe)\n",
  824                             fill_set->freq);
  825                         itr = NULL;
  826                         break;
  827                 } else if (fill_set->freq < itr_set->freq) {
  828                         if (fill->abs_set.freq <= itr->abs_set.freq) {
  829                                 CF_DEBUG(
  830                         "dup done, inserting new level %d after %d\n",
  831                                     fill_set->freq, itr_set->freq);
  832                                 TAILQ_INSERT_AFTER(list, itr, fill, link);
  833                                 sc->all_count++;
  834                         } else {
  835                                 CF_DEBUG("dup set rejecting %d (abs too big)\n",
  836                                     fill_set->freq);
  837                                 itr = NULL;
  838                         }
  839                         break;
  840                 }
  841         }
  842 
  843         /* We didn't find a good place for this new level so free it. */
  844         if (itr == NULL) {
  845                 CF_DEBUG("dup set freeing new level %d (not optimal)\n",
  846                     fill_set->freq);
  847                 free(fill, M_TEMP);
  848                 fill = NULL;
  849         }
  850 
  851         return (fill);
  852 }
  853 
  854 static int
  855 cpufreq_curr_sysctl(SYSCTL_HANDLER_ARGS)
  856 {
  857         struct cpufreq_softc *sc;
  858         struct cf_level *levels;
  859         int count, devcount, error, freq, i, n;
  860         device_t *devs;
  861 
  862         devs = NULL;
  863         sc = oidp->oid_arg1;
  864         levels = malloc(CF_MAX_LEVELS * sizeof(*levels), M_TEMP, M_NOWAIT);
  865         if (levels == NULL)
  866                 return (ENOMEM);
  867 
  868         error = CPUFREQ_GET(sc->dev, &levels[0]);
  869         if (error)
  870                 goto out;
  871         freq = levels[0].total_set.freq;
  872         error = sysctl_handle_int(oidp, &freq, 0, req);
  873         if (error != 0 || req->newptr == NULL)
  874                 goto out;
  875 
  876         /*
  877          * While we only call cpufreq_get() on one device (assuming all
  878          * CPUs have equal levels), we call cpufreq_set() on all CPUs.
  879          * This is needed for some MP systems.
  880          */
  881         error = devclass_get_devices(cpufreq_dc, &devs, &devcount);
  882         if (error)
  883                 goto out;
  884         for (n = 0; n < devcount; n++) {
  885                 count = CF_MAX_LEVELS;
  886                 error = CPUFREQ_LEVELS(devs[n], levels, &count);
  887                 if (error) {
  888                         if (error == E2BIG)
  889                                 printf(
  890                         "cpufreq: need to increase CF_MAX_LEVELS\n");
  891                         break;
  892                 }
  893                 for (i = 0; i < count; i++) {
  894                         if (CPUFREQ_CMP(levels[i].total_set.freq, freq)) {
  895                                 error = CPUFREQ_SET(devs[n], &levels[i],
  896                                     CPUFREQ_PRIO_USER);
  897                                 break;
  898                         }
  899                 }
  900                 if (i == count) {
  901                         error = EINVAL;
  902                         break;
  903                 }
  904         }
  905 
  906 out:
  907         if (devs)
  908                 free(devs, M_TEMP);
  909         if (levels)
  910                 free(levels, M_TEMP);
  911         return (error);
  912 }
  913 
  914 static int
  915 cpufreq_levels_sysctl(SYSCTL_HANDLER_ARGS)
  916 {
  917         struct cpufreq_softc *sc;
  918         struct cf_level *levels;
  919         struct cf_setting *set;
  920         struct sbuf sb;
  921         int count, error, i;
  922 
  923         sc = oidp->oid_arg1;
  924         sbuf_new(&sb, NULL, 128, SBUF_AUTOEXTEND);
  925 
  926         /* Get settings from the device and generate the output string. */
  927         count = CF_MAX_LEVELS;
  928         levels = malloc(count * sizeof(*levels), M_TEMP, M_NOWAIT);
  929         if (levels == NULL) {
  930                 sbuf_delete(&sb);
  931                 return (ENOMEM);
  932         }
  933         error = CPUFREQ_LEVELS(sc->dev, levels, &count);
  934         if (error) {
  935                 if (error == E2BIG)
  936                         printf("cpufreq: need to increase CF_MAX_LEVELS\n");
  937                 goto out;
  938         }
  939         if (count) {
  940                 for (i = 0; i < count; i++) {
  941                         set = &levels[i].total_set;
  942                         sbuf_printf(&sb, "%d/%d ", set->freq, set->power);
  943                 }
  944         } else
  945                 sbuf_cpy(&sb, "");
  946         sbuf_trim(&sb);
  947         sbuf_finish(&sb);
  948         error = sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req);
  949 
  950 out:
  951         free(levels, M_TEMP);
  952         sbuf_delete(&sb);
  953         return (error);
  954 }
  955 
  956 static int
  957 cpufreq_settings_sysctl(SYSCTL_HANDLER_ARGS)
  958 {
  959         device_t dev;
  960         struct cf_setting *sets;
  961         struct sbuf sb;
  962         int error, i, set_count;
  963 
  964         dev = oidp->oid_arg1;
  965         sbuf_new(&sb, NULL, 128, SBUF_AUTOEXTEND);
  966 
  967         /* Get settings from the device and generate the output string. */
  968         set_count = MAX_SETTINGS;
  969         sets = malloc(set_count * sizeof(*sets), M_TEMP, M_NOWAIT);
  970         if (sets == NULL) {
  971                 sbuf_delete(&sb);
  972                 return (ENOMEM);
  973         }
  974         error = CPUFREQ_DRV_SETTINGS(dev, sets, &set_count);
  975         if (error)
  976                 goto out;
  977         if (set_count) {
  978                 for (i = 0; i < set_count; i++)
  979                         sbuf_printf(&sb, "%d/%d ", sets[i].freq, sets[i].power);
  980         } else
  981                 sbuf_cpy(&sb, "");
  982         sbuf_trim(&sb);
  983         sbuf_finish(&sb);
  984         error = sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req);
  985 
  986 out:
  987         free(sets, M_TEMP);
  988         sbuf_delete(&sb);
  989         return (error);
  990 }
  991 
  992 int
  993 cpufreq_register(device_t dev)
  994 {
  995         struct cpufreq_softc *sc;
  996         device_t cf_dev, cpu_dev;
  997 
  998         /* Add a sysctl to get each driver's settings separately. */
  999         SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
 1000             SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
 1001             OID_AUTO, "freq_settings", CTLTYPE_STRING | CTLFLAG_RD, dev, 0,
 1002             cpufreq_settings_sysctl, "A", "CPU frequency driver settings");
 1003 
 1004         /*
 1005          * Add only one cpufreq device to each CPU.  Currently, all CPUs
 1006          * must offer the same levels and be switched at the same time.
 1007          */
 1008         cpu_dev = device_get_parent(dev);
 1009         if ((cf_dev = device_find_child(cpu_dev, "cpufreq", -1))) {
 1010                 sc = device_get_softc(cf_dev);
 1011                 sc->max_mhz = CPUFREQ_VAL_UNKNOWN;
 1012                 return (0);
 1013         }
 1014 
 1015         /* Add the child device and possibly sysctls. */
 1016         cf_dev = BUS_ADD_CHILD(cpu_dev, 0, "cpufreq", -1);
 1017         if (cf_dev == NULL)
 1018                 return (ENOMEM);
 1019         device_quiet(cf_dev);
 1020 
 1021         return (device_probe_and_attach(cf_dev));
 1022 }
 1023 
 1024 int
 1025 cpufreq_unregister(device_t dev)
 1026 {
 1027         device_t cf_dev, *devs;
 1028         int cfcount, devcount, error, i, type;
 1029 
 1030         /*
 1031          * If this is the last cpufreq child device, remove the control
 1032          * device as well.  We identify cpufreq children by calling a method
 1033          * they support.
 1034          */
 1035         error = device_get_children(device_get_parent(dev), &devs, &devcount);
 1036         if (error)
 1037                 return (error);
 1038         cf_dev = device_find_child(device_get_parent(dev), "cpufreq", -1);
 1039         if (cf_dev == NULL) {
 1040                 device_printf(dev,
 1041         "warning: cpufreq_unregister called with no cpufreq device active\n");
 1042                 return (0);
 1043         }
 1044         cfcount = 0;
 1045         for (i = 0; i < devcount; i++) {
 1046                 if (!device_is_attached(devs[i]))
 1047                         continue;
 1048                 if (CPUFREQ_DRV_TYPE(devs[i], &type) == 0)
 1049                         cfcount++;
 1050         }
 1051         if (cfcount <= 1)
 1052                 device_delete_child(device_get_parent(cf_dev), cf_dev);
 1053         free(devs, M_TEMP);
 1054 
 1055         return (0);
 1056 }
 1057 
 1058 int
 1059 cpufreq_settings_changed(device_t dev)
 1060 {
 1061 
 1062         EVENTHANDLER_INVOKE(cpufreq_levels_changed,
 1063             device_get_unit(device_get_parent(dev)));
 1064         return (0);
 1065 }

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