/*- * Copyright (c) 2004-2005 Nate Lawson (SDG) * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "cpufreq_if.h" /* * Common CPU frequency glue code. Drivers for specific hardware can * attach this interface to allow users to get/set the CPU frequency. */ /* * Number of levels we can handle. Levels are synthesized from settings * so for M settings and N drivers, there may be M*N levels. */ #define CF_MAX_LEVELS 64 struct cpufreq_softc { struct cf_level curr_level; int curr_priority; struct cf_level saved_level; int saved_priority; struct cf_level_lst all_levels; int all_count; int max_mhz; device_t dev; struct sysctl_ctx_list sysctl_ctx; }; struct cf_setting_array { struct cf_setting sets[MAX_SETTINGS]; int count; TAILQ_ENTRY(cf_setting_array) link; }; TAILQ_HEAD(cf_setting_lst, cf_setting_array); static int cpufreq_attach(device_t dev); static int cpufreq_detach(device_t dev); static void cpufreq_evaluate(void *arg); static int cf_set_method(device_t dev, const struct cf_level *level, int priority); static int cf_get_method(device_t dev, struct cf_level *level); static int cf_levels_method(device_t dev, struct cf_level *levels, int *count); static int cpufreq_insert_abs(struct cpufreq_softc *sc, struct cf_setting *sets, int count); static int cpufreq_expand_set(struct cpufreq_softc *sc, struct cf_setting_array *set_arr); static struct cf_level *cpufreq_dup_set(struct cpufreq_softc *sc, struct cf_level *dup, struct cf_setting *set); static int cpufreq_curr_sysctl(SYSCTL_HANDLER_ARGS); static int cpufreq_levels_sysctl(SYSCTL_HANDLER_ARGS); static int cpufreq_settings_sysctl(SYSCTL_HANDLER_ARGS); static device_method_t cpufreq_methods[] = { DEVMETHOD(device_probe, bus_generic_probe), DEVMETHOD(device_attach, cpufreq_attach), DEVMETHOD(device_detach, cpufreq_detach), DEVMETHOD(cpufreq_set, cf_set_method), DEVMETHOD(cpufreq_get, cf_get_method), DEVMETHOD(cpufreq_levels, cf_levels_method), {0, 0} }; static driver_t cpufreq_driver = { "cpufreq", cpufreq_methods, sizeof(struct cpufreq_softc) }; static devclass_t cpufreq_dc; DRIVER_MODULE(cpufreq, cpu, cpufreq_driver, cpufreq_dc, 0, 0); static eventhandler_tag cf_ev_tag; static int cpufreq_attach(device_t dev) { struct cpufreq_softc *sc; device_t parent; int numdevs; sc = device_get_softc(dev); parent = device_get_parent(dev); sc->dev = dev; sysctl_ctx_init(&sc->sysctl_ctx); TAILQ_INIT(&sc->all_levels); sc->curr_level.total_set.freq = CPUFREQ_VAL_UNKNOWN; sc->saved_level.total_set.freq = CPUFREQ_VAL_UNKNOWN; sc->max_mhz = CPUFREQ_VAL_UNKNOWN; /* * Only initialize one set of sysctls for all CPUs. In the future, * if multiple CPUs can have different settings, we can move these * sysctls to be under every CPU instead of just the first one. */ numdevs = devclass_get_count(cpufreq_dc); if (numdevs > 1) return (0); SYSCTL_ADD_PROC(&sc->sysctl_ctx, SYSCTL_CHILDREN(device_get_sysctl_tree(parent)), OID_AUTO, "freq", CTLTYPE_INT | CTLFLAG_RW, sc, 0, cpufreq_curr_sysctl, "I", "Current CPU frequency"); SYSCTL_ADD_PROC(&sc->sysctl_ctx, SYSCTL_CHILDREN(device_get_sysctl_tree(parent)), OID_AUTO, "freq_levels", CTLTYPE_STRING | CTLFLAG_RD, sc, 0, cpufreq_levels_sysctl, "A", "CPU frequency levels"); cf_ev_tag = EVENTHANDLER_REGISTER(cpufreq_changed, cpufreq_evaluate, NULL, EVENTHANDLER_PRI_ANY); return (0); } static int cpufreq_detach(device_t dev) { struct cpufreq_softc *sc; int numdevs; sc = device_get_softc(dev); sysctl_ctx_free(&sc->sysctl_ctx); /* Only clean up these resources when the last device is detaching. */ numdevs = devclass_get_count(cpufreq_dc); if (numdevs == 1) EVENTHANDLER_DEREGISTER(cpufreq_changed, cf_ev_tag); return (0); } static void cpufreq_evaluate(void *arg) { /* TODO: Re-evaluate when notified of changes to drivers. */ } static int cf_set_method(device_t dev, const struct cf_level *level, int priority) { struct cpufreq_softc *sc; const struct cf_setting *set; struct pcpu *pc; int cpu_id, error, i; sc = device_get_softc(dev); /* * Check that the TSC isn't being used as a timecounter. * If it is, then return EBUSY and refuse to change the * clock speed. */ if (strcmp(timecounter->tc_name, "TSC") == 0) return (EBUSY); /* * If the caller didn't specify a level and one is saved, prepare to * restore the saved level. If none has been saved, return an error. * If they did specify one, but the requested level has a lower * priority, don't allow the new level right now. */ if (level == NULL) { if (sc->saved_level.total_set.freq != CPUFREQ_VAL_UNKNOWN) { level = &sc->saved_level; priority = sc->saved_priority; } else return (ENXIO); } else if (priority < sc->curr_priority) return (EPERM); /* If already at this level, just return. */ if (CPUFREQ_CMP(sc->curr_level.total_set.freq, level->total_set.freq)) return (0); /* First, set the absolute frequency via its driver. */ set = &level->abs_set; if (set->dev) { if (!device_is_attached(set->dev)) { error = ENXIO; goto out; } /* Bind to the target CPU before switching, if necessary. */ cpu_id = PCPU_GET(cpuid); pc = cpu_get_pcpu(set->dev); if (cpu_id != pc->pc_cpuid) { mtx_lock_spin(&sched_lock); sched_bind(curthread, pc->pc_cpuid); mtx_unlock_spin(&sched_lock); } error = CPUFREQ_DRV_SET(set->dev, set); if (cpu_id != pc->pc_cpuid) { mtx_lock_spin(&sched_lock); sched_unbind(curthread); mtx_unlock_spin(&sched_lock); } if (error) { goto out; } } /* Next, set any/all relative frequencies via their drivers. */ for (i = 0; i < level->rel_count; i++) { set = &level->rel_set[i]; if (!device_is_attached(set->dev)) { error = ENXIO; goto out; } /* Bind to the target CPU before switching, if necessary. */ cpu_id = PCPU_GET(cpuid); pc = cpu_get_pcpu(set->dev); if (cpu_id != pc->pc_cpuid) { mtx_lock_spin(&sched_lock); sched_bind(curthread, pc->pc_cpuid); mtx_unlock_spin(&sched_lock); } error = CPUFREQ_DRV_SET(set->dev, set); if (cpu_id != pc->pc_cpuid) { mtx_lock_spin(&sched_lock); sched_unbind(curthread); mtx_unlock_spin(&sched_lock); } if (error) { /* XXX Back out any successful setting? */ goto out; } } /* If we were restoring a saved state, reset it to "unused". */ if (level == &sc->saved_level) { sc->saved_level.total_set.freq = CPUFREQ_VAL_UNKNOWN; sc->saved_priority = 0; } /* * Before recording the current level, check if we're going to a * higher priority and have not saved a level yet. If so, save the * previous level and priority. */ if (sc->curr_level.total_set.freq != CPUFREQ_VAL_UNKNOWN && sc->saved_level.total_set.freq == CPUFREQ_VAL_UNKNOWN && priority > sc->curr_priority) { sc->saved_level = sc->curr_level; sc->saved_priority = sc->curr_priority; } sc->curr_level = *level; sc->curr_priority = priority; error = 0; out: if (error) device_printf(set->dev, "set freq failed, err %d\n", error); return (error); } static int cf_get_method(device_t dev, struct cf_level *level) { struct cpufreq_softc *sc; struct cf_level *levels; struct cf_setting *curr_set, set; struct pcpu *pc; device_t *devs; int count, error, i, numdevs; uint64_t rate; sc = device_get_softc(dev); curr_set = &sc->curr_level.total_set; levels = NULL; /* If we already know the current frequency, we're done. */ if (curr_set->freq != CPUFREQ_VAL_UNKNOWN) goto out; /* * We need to figure out the current level. Loop through every * driver, getting the current setting. Then, attempt to get a best * match of settings against each level. */ count = CF_MAX_LEVELS; levels = malloc(count * sizeof(*levels), M_TEMP, M_NOWAIT); if (levels == NULL) return (ENOMEM); error = CPUFREQ_LEVELS(sc->dev, levels, &count); if (error) { if (error == E2BIG) printf("cpufreq: need to increase CF_MAX_LEVELS\n"); goto out; } error = device_get_children(device_get_parent(dev), &devs, &numdevs); if (error) goto out; for (i = 0; i < numdevs && curr_set->freq == CPUFREQ_VAL_UNKNOWN; i++) { if (!device_is_attached(devs[i])) continue; error = CPUFREQ_DRV_GET(devs[i], &set); if (error) continue; for (i = 0; i < count; i++) { if (CPUFREQ_CMP(set.freq, levels[i].total_set.freq)) { sc->curr_level = levels[i]; break; } } } free(devs, M_TEMP); if (curr_set->freq != CPUFREQ_VAL_UNKNOWN) goto out; /* * We couldn't find an exact match, so attempt to estimate and then * match against a level. */ pc = cpu_get_pcpu(dev); if (pc == NULL) { error = ENXIO; goto out; } cpu_est_clockrate(pc->pc_cpuid, &rate); rate /= 1000000; for (i = 0; i < count; i++) { if (CPUFREQ_CMP(rate, levels[i].total_set.freq)) { sc->curr_level = levels[i]; break; } } out: if (levels) free(levels, M_TEMP); *level = sc->curr_level; return (0); } static int cf_levels_method(device_t dev, struct cf_level *levels, int *count) { struct cf_setting_array *set_arr; struct cf_setting_lst rel_sets; struct cpufreq_softc *sc; struct cf_level *lev; struct cf_setting *sets; struct pcpu *pc; device_t *devs; int error, i, numdevs, set_count, type; uint64_t rate; if (levels == NULL || count == NULL) return (EINVAL); TAILQ_INIT(&rel_sets); sc = device_get_softc(dev); error = device_get_children(device_get_parent(dev), &devs, &numdevs); if (error) return (error); sets = malloc(MAX_SETTINGS * sizeof(*sets), M_TEMP, M_NOWAIT); if (sets == NULL) { free(devs, M_TEMP); return (ENOMEM); } /* Get settings from all cpufreq drivers. */ for (i = 0; i < numdevs; i++) { /* Skip devices that aren't ready. */ if (!device_is_attached(devs[i])) continue; /* * Get settings, skipping drivers that offer no settings or * provide settings for informational purposes only. */ error = CPUFREQ_DRV_TYPE(devs[i], &type); if (error || (type & CPUFREQ_FLAG_INFO_ONLY)) continue; set_count = MAX_SETTINGS; error = CPUFREQ_DRV_SETTINGS(devs[i], sets, &set_count); if (error || set_count == 0) continue; /* Add the settings to our absolute/relative lists. */ switch (type & CPUFREQ_TYPE_MASK) { case CPUFREQ_TYPE_ABSOLUTE: error = cpufreq_insert_abs(sc, sets, set_count); break; case CPUFREQ_TYPE_RELATIVE: set_arr = malloc(sizeof(*set_arr), M_TEMP, M_NOWAIT); if (set_arr == NULL) { error = ENOMEM; goto out; } bcopy(sets, set_arr->sets, set_count * sizeof(*sets)); set_arr->count = set_count; TAILQ_INSERT_TAIL(&rel_sets, set_arr, link); break; default: error = EINVAL; break; } if (error) goto out; } /* * If there are no absolute levels, create a fake one at 100%. We * then cache the clockrate for later use as our base frequency. * * XXX This assumes that the first time through, if we only have * relative drivers, the CPU is currently running at 100%. */ if (TAILQ_EMPTY(&sc->all_levels)) { if (sc->max_mhz == CPUFREQ_VAL_UNKNOWN) { pc = cpu_get_pcpu(dev); cpu_est_clockrate(pc->pc_cpuid, &rate); sc->max_mhz = rate / 1000000; } memset(&sets[0], CPUFREQ_VAL_UNKNOWN, sizeof(*sets)); sets[0].freq = sc->max_mhz; sets[0].dev = NULL; error = cpufreq_insert_abs(sc, sets, 1); if (error) goto out; } /* Create a combined list of absolute + relative levels. */ TAILQ_FOREACH(set_arr, &rel_sets, link) cpufreq_expand_set(sc, set_arr); /* If the caller doesn't have enough space, return the actual count. */ if (sc->all_count > *count) { *count = sc->all_count; error = E2BIG; goto out; } /* Finally, output the list of levels. */ i = 0; TAILQ_FOREACH(lev, &sc->all_levels, link) { levels[i] = *lev; i++; } *count = sc->all_count; error = 0; out: /* Clear all levels since we regenerate them each time. */ while ((lev = TAILQ_FIRST(&sc->all_levels)) != NULL) { TAILQ_REMOVE(&sc->all_levels, lev, link); free(lev, M_TEMP); } while ((set_arr = TAILQ_FIRST(&rel_sets)) != NULL) { TAILQ_REMOVE(&rel_sets, set_arr, link); free(set_arr, M_TEMP); } sc->all_count = 0; free(devs, M_TEMP); free(sets, M_TEMP); return (error); } /* * Create levels for an array of absolute settings and insert them in * sorted order in the specified list. */ static int cpufreq_insert_abs(struct cpufreq_softc *sc, struct cf_setting *sets, int count) { struct cf_level_lst *list; struct cf_level *level, *search; int i; list = &sc->all_levels; for (i = 0; i < count; i++) { level = malloc(sizeof(*level), M_TEMP, M_NOWAIT | M_ZERO); if (level == NULL) return (ENOMEM); level->abs_set = sets[i]; level->total_set = sets[i]; level->total_set.dev = NULL; sc->all_count++; if (TAILQ_EMPTY(list)) { TAILQ_INSERT_HEAD(list, level, link); continue; } TAILQ_FOREACH_REVERSE(search, list, cf_level_lst, link) { if (sets[i].freq <= search->total_set.freq) { TAILQ_INSERT_AFTER(list, search, level, link); break; } } } return (0); } /* * Expand a group of relative settings, creating derived levels from them. */ static int cpufreq_expand_set(struct cpufreq_softc *sc, struct cf_setting_array *set_arr) { struct cf_level *fill, *search; struct cf_setting *set; int i; TAILQ_FOREACH(search, &sc->all_levels, link) { /* Skip this level if we've already modified it. */ for (i = 0; i < search->rel_count; i++) { if (search->rel_set[i].dev == set_arr->sets[0].dev) break; } if (i != search->rel_count) continue; /* Add each setting to the level, duplicating if necessary. */ for (i = 0; i < set_arr->count; i++) { set = &set_arr->sets[i]; /* * If this setting is less than 100%, split the level * into two and add this setting to the new level. */ fill = search; if (set->freq < 10000) fill = cpufreq_dup_set(sc, search, set); /* * The new level was a duplicate of an existing level * so we freed it. Go to the next setting. */ if (fill == NULL) continue; /* Add this setting to the existing or new level. */ KASSERT(fill->rel_count < MAX_SETTINGS, ("cpufreq: too many relative drivers (%d)", MAX_SETTINGS)); fill->rel_set[fill->rel_count] = *set; fill->rel_count++; } } return (0); } static struct cf_level * cpufreq_dup_set(struct cpufreq_softc *sc, struct cf_level *dup, struct cf_setting *set) { struct cf_level_lst *list; struct cf_level *fill, *itr; struct cf_setting *fill_set, *itr_set; int i; /* * Create a new level, copy it from the old one, and update the * total frequency and power by the percentage specified in the * relative setting. */ fill = malloc(sizeof(*fill), M_TEMP, M_NOWAIT); if (fill == NULL) return (NULL); *fill = *dup; fill_set = &fill->total_set; fill_set->freq = ((uint64_t)fill_set->freq * set->freq) / 10000; if (fill_set->power != CPUFREQ_VAL_UNKNOWN) { fill_set->power = ((uint64_t)fill_set->power * set->freq) / 10000; } if (set->lat != CPUFREQ_VAL_UNKNOWN) { if (fill_set->lat != CPUFREQ_VAL_UNKNOWN) fill_set->lat += set->lat; else fill_set->lat = set->lat; } /* * If we copied an old level that we already modified (say, at 100%), * we need to remove that setting before adding this one. Since we * process each setting array in order, we know any settings for this * driver will be found at the end. */ for (i = fill->rel_count; i != 0; i--) { if (fill->rel_set[i - 1].dev != set->dev) break; fill->rel_count--; } /* * Insert the new level in sorted order. If we find a duplicate, * free the new level. We can do this since any existing level will * be guaranteed to have the same or less settings and thus consume * less power. For example, a level with one absolute setting of * 800 Mhz uses less power than one composed of an absolute setting * of 1600 Mhz and a relative setting at 50%. */ list = &sc->all_levels; if (TAILQ_EMPTY(list)) { TAILQ_INSERT_HEAD(list, fill, link); } else { TAILQ_FOREACH_REVERSE(itr, list, cf_level_lst, link) { itr_set = &itr->total_set; if (CPUFREQ_CMP(fill_set->freq, itr_set->freq)) { free(fill, M_TEMP); fill = NULL; break; } else if (fill_set->freq < itr_set->freq) { TAILQ_INSERT_AFTER(list, itr, fill, link); sc->all_count++; break; } } } return (fill); } static int cpufreq_curr_sysctl(SYSCTL_HANDLER_ARGS) { struct cpufreq_softc *sc; struct cf_level *levels; int count, devcount, error, freq, i, n; device_t *devs; devs = NULL; sc = oidp->oid_arg1; levels = malloc(CF_MAX_LEVELS * sizeof(*levels), M_TEMP, M_NOWAIT); if (levels == NULL) return (ENOMEM); error = CPUFREQ_GET(sc->dev, &levels[0]); if (error) goto out; freq = levels[0].total_set.freq; error = sysctl_handle_int(oidp, &freq, 0, req); if (error != 0 || req->newptr == NULL) goto out; /* * While we only call cpufreq_get() on one device (assuming all * CPUs have equal levels), we call cpufreq_set() on all CPUs. * This is needed for some MP systems. */ error = devclass_get_devices(cpufreq_dc, &devs, &devcount); if (error) goto out; for (n = 0; n < devcount; n++) { count = CF_MAX_LEVELS; error = CPUFREQ_LEVELS(devs[n], levels, &count); if (error) { if (error == E2BIG) printf( "cpufreq: need to increase CF_MAX_LEVELS\n"); break; } for (i = 0; i < count; i++) { if (CPUFREQ_CMP(levels[i].total_set.freq, freq)) { error = CPUFREQ_SET(devs[n], &levels[i], CPUFREQ_PRIO_USER); break; } } if (i == count) { error = EINVAL; break; } } out: if (devs) free(devs, M_TEMP); if (levels) free(levels, M_TEMP); return (error); } static int cpufreq_levels_sysctl(SYSCTL_HANDLER_ARGS) { struct cpufreq_softc *sc; struct cf_level *levels; struct cf_setting *set; struct sbuf sb; int count, error, i; sc = oidp->oid_arg1; sbuf_new(&sb, NULL, 128, SBUF_AUTOEXTEND); /* Get settings from the device and generate the output string. */ count = CF_MAX_LEVELS; levels = malloc(count * sizeof(*levels), M_TEMP, M_NOWAIT); if (levels == NULL) return (ENOMEM); error = CPUFREQ_LEVELS(sc->dev, levels, &count); if (error) { if (error == E2BIG) printf("cpufreq: need to increase CF_MAX_LEVELS\n"); goto out; } if (count) { for (i = 0; i < count; i++) { set = &levels[i].total_set; sbuf_printf(&sb, "%d/%d ", set->freq, set->power); } } else sbuf_cpy(&sb, "0"); sbuf_trim(&sb); sbuf_finish(&sb); error = sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req); out: free(levels, M_TEMP); sbuf_delete(&sb); return (error); } static int cpufreq_settings_sysctl(SYSCTL_HANDLER_ARGS) { device_t dev; struct cf_setting *sets; struct sbuf sb; int error, i, set_count; dev = oidp->oid_arg1; sbuf_new(&sb, NULL, 128, SBUF_AUTOEXTEND); /* Get settings from the device and generate the output string. */ set_count = MAX_SETTINGS; sets = malloc(set_count * sizeof(*sets), M_TEMP, M_NOWAIT); if (sets == NULL) return (ENOMEM); error = CPUFREQ_DRV_SETTINGS(dev, sets, &set_count); if (error) goto out; if (set_count) { for (i = 0; i < set_count; i++) sbuf_printf(&sb, "%d/%d ", sets[i].freq, sets[i].power); } else sbuf_cpy(&sb, "0"); sbuf_trim(&sb); sbuf_finish(&sb); error = sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req); out: free(sets, M_TEMP); sbuf_delete(&sb); return (error); } int cpufreq_register(device_t dev) { struct cpufreq_softc *sc; device_t cf_dev, cpu_dev; /* Add a sysctl to get each driver's settings separately. */ SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev), SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO, "freq_settings", CTLTYPE_STRING | CTLFLAG_RD, dev, 0, cpufreq_settings_sysctl, "A", "CPU frequency driver settings"); /* * Add only one cpufreq device to each CPU. Currently, all CPUs * must offer the same levels and be switched at the same time. */ cpu_dev = device_get_parent(dev); if ((cf_dev = device_find_child(cpu_dev, "cpufreq", -1))) { sc = device_get_softc(cf_dev); sc->max_mhz = CPUFREQ_VAL_UNKNOWN; return (0); } /* Add the child device and possibly sysctls. */ cf_dev = BUS_ADD_CHILD(cpu_dev, 0, "cpufreq", -1); if (cf_dev == NULL) return (ENOMEM); device_quiet(cf_dev); return (device_probe_and_attach(cf_dev)); } int cpufreq_unregister(device_t dev) { device_t cf_dev, *devs; int cfcount, devcount, error, i, type; /* * If this is the last cpufreq child device, remove the control * device as well. We identify cpufreq children by calling a method * they support. */ error = device_get_children(device_get_parent(dev), &devs, &devcount); if (error) return (error); cf_dev = device_find_child(device_get_parent(dev), "cpufreq", -1); cfcount = 0; for (i = 0; i < devcount; i++) { if (!device_is_attached(devs[i])) continue; if (CPUFREQ_DRV_TYPE(devs[i], &type) == 0) cfcount++; } if (cfcount <= 1) device_delete_child(device_get_parent(cf_dev), cf_dev); free(devs, M_TEMP); return (0); }