diff options
Diffstat (limited to 'drivers/cpufreq/cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 418 |
1 files changed, 299 insertions, 119 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index b02824d092e7..a6f65954b0ab 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -39,13 +39,13 @@ * level driver of CPUFreq support, and its spinlock. This lock * also protects the cpufreq_cpu_data array. */ -static struct cpufreq_driver *cpufreq_driver; +static struct cpufreq_driver __rcu *cpufreq_driver; static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data); #ifdef CONFIG_HOTPLUG_CPU /* This one keeps track of the previously set governor of a removed CPU */ static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor); #endif -static DEFINE_SPINLOCK(cpufreq_driver_lock); +static DEFINE_RWLOCK(cpufreq_driver_lock); /* * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure @@ -128,23 +128,36 @@ void disable_cpufreq(void) static LIST_HEAD(cpufreq_governor_list); static DEFINE_MUTEX(cpufreq_governor_mutex); +bool have_governor_per_policy(void) +{ + bool have_governor_per_policy; + rcu_read_lock(); + have_governor_per_policy = + rcu_dereference(cpufreq_driver)->have_governor_per_policy; + rcu_read_unlock(); + return have_governor_per_policy; +} + static struct cpufreq_policy *__cpufreq_cpu_get(unsigned int cpu, bool sysfs) { struct cpufreq_policy *data; + struct cpufreq_driver *driver; unsigned long flags; if (cpu >= nr_cpu_ids) goto err_out; /* get the cpufreq driver */ - spin_lock_irqsave(&cpufreq_driver_lock, flags); + rcu_read_lock(); + driver = rcu_dereference(cpufreq_driver); - if (!cpufreq_driver) + if (!driver) goto err_out_unlock; - if (!try_module_get(cpufreq_driver->owner)) + if (!try_module_get(driver->owner)) goto err_out_unlock; + read_lock_irqsave(&cpufreq_driver_lock, flags); /* get the CPU */ data = per_cpu(cpufreq_cpu_data, cpu); @@ -155,13 +168,15 @@ static struct cpufreq_policy *__cpufreq_cpu_get(unsigned int cpu, bool sysfs) if (!sysfs && !kobject_get(&data->kobj)) goto err_out_put_module; - spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + read_unlock_irqrestore(&cpufreq_driver_lock, flags); + rcu_read_unlock(); return data; err_out_put_module: - module_put(cpufreq_driver->owner); + module_put(driver->owner); + read_unlock_irqrestore(&cpufreq_driver_lock, flags); err_out_unlock: - spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + rcu_read_unlock(); err_out: return NULL; } @@ -184,7 +199,9 @@ static void __cpufreq_cpu_put(struct cpufreq_policy *data, bool sysfs) { if (!sysfs) kobject_put(&data->kobj); - module_put(cpufreq_driver->owner); + rcu_read_lock(); + module_put(rcu_dereference(cpufreq_driver)->owner); + rcu_read_unlock(); } void cpufreq_cpu_put(struct cpufreq_policy *data) @@ -244,32 +261,20 @@ static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) #endif -/** - * cpufreq_notify_transition - call notifier chain and adjust_jiffies - * on frequency transition. - * - * This function calls the transition notifiers and the "adjust_jiffies" - * function. It is called twice on all CPU frequency changes that have - * external effects. - */ -void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state) +void __cpufreq_notify_transition(struct cpufreq_policy *policy, + struct cpufreq_freqs *freqs, unsigned int state) { - struct cpufreq_policy *policy; - unsigned long flags; - BUG_ON(irqs_disabled()); if (cpufreq_disabled()) return; - freqs->flags = cpufreq_driver->flags; + rcu_read_lock(); + freqs->flags = rcu_dereference(cpufreq_driver)->flags; + rcu_read_unlock(); pr_debug("notification %u of frequency transition to %u kHz\n", state, freqs->new); - spin_lock_irqsave(&cpufreq_driver_lock, flags); - policy = per_cpu(cpufreq_cpu_data, freqs->cpu); - spin_unlock_irqrestore(&cpufreq_driver_lock, flags); - switch (state) { case CPUFREQ_PRECHANGE: @@ -277,7 +282,7 @@ void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state) * which is not equal to what the cpufreq core thinks is * "old frequency". */ - if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { + if (!(freqs->flags & CPUFREQ_CONST_LOOPS)) { if ((policy) && (policy->cpu == freqs->cpu) && (policy->cur) && (policy->cur != freqs->old)) { pr_debug("Warning: CPU frequency is" @@ -303,6 +308,20 @@ void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state) break; } } +/** + * cpufreq_notify_transition - call notifier chain and adjust_jiffies + * on frequency transition. + * + * This function calls the transition notifiers and the "adjust_jiffies" + * function. It is called twice on all CPU frequency changes that have + * external effects. + */ +void cpufreq_notify_transition(struct cpufreq_policy *policy, + struct cpufreq_freqs *freqs, unsigned int state) +{ + for_each_cpu(freqs->cpu, policy->cpus) + __cpufreq_notify_transition(policy, freqs, state); +} EXPORT_SYMBOL_GPL(cpufreq_notify_transition); @@ -329,11 +348,21 @@ static int cpufreq_parse_governor(char *str_governor, unsigned int *policy, struct cpufreq_governor **governor) { int err = -EINVAL; - - if (!cpufreq_driver) + struct cpufreq_driver *driver; + bool has_setpolicy; + bool has_target; + + rcu_read_lock(); + driver = rcu_dereference(cpufreq_driver); + if (!driver) { + rcu_read_unlock(); goto out; + } + has_setpolicy = driver->setpolicy ? true : false; + has_target = driver->target ? true : false; + rcu_read_unlock(); - if (cpufreq_driver->setpolicy) { + if (has_setpolicy) { if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) { *policy = CPUFREQ_POLICY_PERFORMANCE; err = 0; @@ -342,7 +371,7 @@ static int cpufreq_parse_governor(char *str_governor, unsigned int *policy, *policy = CPUFREQ_POLICY_POWERSAVE; err = 0; } - } else if (cpufreq_driver->target) { + } else if (has_target) { struct cpufreq_governor *t; mutex_lock(&cpufreq_governor_mutex); @@ -493,7 +522,12 @@ static ssize_t store_scaling_governor(struct cpufreq_policy *policy, */ static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf) { - return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name); + ssize_t size; + rcu_read_lock(); + size = scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", + rcu_dereference(cpufreq_driver)->name); + rcu_read_unlock(); + return size; } /** @@ -505,10 +539,13 @@ static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy, ssize_t i = 0; struct cpufreq_governor *t; - if (!cpufreq_driver->target) { + rcu_read_lock(); + if (!rcu_dereference(cpufreq_driver)->target) { + rcu_read_unlock(); i += sprintf(buf, "performance powersave"); goto out; } + rcu_read_unlock(); list_for_each_entry(t, &cpufreq_governor_list, governor_list) { if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) @@ -586,9 +623,15 @@ static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf) static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf) { unsigned int limit; + int (*bios_limit)(int cpu, unsigned int *limit); int ret; - if (cpufreq_driver->bios_limit) { - ret = cpufreq_driver->bios_limit(policy->cpu, &limit); + + rcu_read_lock(); + bios_limit = rcu_dereference(cpufreq_driver)->bios_limit; + rcu_read_unlock(); + + if (bios_limit) { + ret = bios_limit(policy->cpu, &limit); if (!ret) return sprintf(buf, "%u\n", limit); } @@ -731,6 +774,7 @@ static int cpufreq_add_dev_interface(unsigned int cpu, { struct cpufreq_policy new_policy; struct freq_attr **drv_attr; + struct cpufreq_driver *driver; unsigned long flags; int ret = 0; unsigned int j; @@ -742,35 +786,38 @@ static int cpufreq_add_dev_interface(unsigned int cpu, return ret; /* set up files for this cpu device */ - drv_attr = cpufreq_driver->attr; + rcu_read_lock(); + driver = rcu_dereference(cpufreq_driver); + drv_attr = driver->attr; while ((drv_attr) && (*drv_attr)) { ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr)); if (ret) - goto err_out_kobj_put; + goto err_out_unlock; drv_attr++; } - if (cpufreq_driver->get) { + if (driver->get) { ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr); if (ret) - goto err_out_kobj_put; + goto err_out_unlock; } - if (cpufreq_driver->target) { + if (driver->target) { ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr); if (ret) - goto err_out_kobj_put; + goto err_out_unlock; } - if (cpufreq_driver->bios_limit) { + if (driver->bios_limit) { ret = sysfs_create_file(&policy->kobj, &bios_limit.attr); if (ret) - goto err_out_kobj_put; + goto err_out_unlock; } + rcu_read_unlock(); - spin_lock_irqsave(&cpufreq_driver_lock, flags); + write_lock_irqsave(&cpufreq_driver_lock, flags); for_each_cpu(j, policy->cpus) { per_cpu(cpufreq_cpu_data, j) = policy; per_cpu(cpufreq_policy_cpu, j) = policy->cpu; } - spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + write_unlock_irqrestore(&cpufreq_driver_lock, flags); ret = cpufreq_add_dev_symlink(cpu, policy); if (ret) @@ -786,12 +833,20 @@ static int cpufreq_add_dev_interface(unsigned int cpu, policy->user_policy.governor = policy->governor; if (ret) { + int (*exit)(struct cpufreq_policy *policy); + pr_debug("setting policy failed\n"); - if (cpufreq_driver->exit) - cpufreq_driver->exit(policy); + rcu_read_lock(); + exit = rcu_dereference(cpufreq_driver)->exit; + rcu_read_unlock(); + if (exit) + exit(policy); + } return ret; +err_out_unlock: + rcu_read_unlock(); err_out_kobj_put: kobject_put(&policy->kobj); wait_for_completion(&policy->kobj_unregister); @@ -803,27 +858,34 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling, struct device *dev) { struct cpufreq_policy *policy; - int ret = 0; + int ret = 0, has_target = 0; unsigned long flags; policy = cpufreq_cpu_get(sibling); WARN_ON(!policy); - __cpufreq_governor(policy, CPUFREQ_GOV_STOP); + rcu_read_lock(); + has_target = !!rcu_dereference(cpufreq_driver)->target; + rcu_read_unlock(); + + if (has_target) + __cpufreq_governor(policy, CPUFREQ_GOV_STOP); lock_policy_rwsem_write(sibling); - spin_lock_irqsave(&cpufreq_driver_lock, flags); + write_lock_irqsave(&cpufreq_driver_lock, flags); cpumask_set_cpu(cpu, policy->cpus); per_cpu(cpufreq_policy_cpu, cpu) = policy->cpu; per_cpu(cpufreq_cpu_data, cpu) = policy; - spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + write_unlock_irqrestore(&cpufreq_driver_lock, flags); unlock_policy_rwsem_write(sibling); - __cpufreq_governor(policy, CPUFREQ_GOV_START); - __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); + if (has_target) { + __cpufreq_governor(policy, CPUFREQ_GOV_START); + __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); + } ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"); if (ret) { @@ -849,6 +911,8 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) unsigned int j, cpu = dev->id; int ret = -ENOMEM; struct cpufreq_policy *policy; + struct cpufreq_driver *driver; + int (*init)(struct cpufreq_policy *policy); unsigned long flags; #ifdef CONFIG_HOTPLUG_CPU struct cpufreq_governor *gov; @@ -871,22 +935,27 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) #ifdef CONFIG_HOTPLUG_CPU /* Check if this cpu was hot-unplugged earlier and has siblings */ - spin_lock_irqsave(&cpufreq_driver_lock, flags); + read_lock_irqsave(&cpufreq_driver_lock, flags); for_each_online_cpu(sibling) { struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling); if (cp && cpumask_test_cpu(cpu, cp->related_cpus)) { - spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + read_unlock_irqrestore(&cpufreq_driver_lock, flags); return cpufreq_add_policy_cpu(cpu, sibling, dev); } } - spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + read_unlock_irqrestore(&cpufreq_driver_lock, flags); #endif #endif - if (!try_module_get(cpufreq_driver->owner)) { + rcu_read_lock(); + driver = rcu_dereference(cpufreq_driver); + if (!try_module_get(driver->owner)) { + rcu_read_unlock(); ret = -EINVAL; goto module_out; } + init = driver->init; + rcu_read_unlock(); policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL); if (!policy) @@ -911,7 +980,7 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) /* call driver. From then on the cpufreq must be able * to accept all calls to ->verify and ->setpolicy for this CPU */ - ret = cpufreq_driver->init(policy); + ret = init(policy); if (ret) { pr_debug("initialization failed\n"); goto err_set_policy_cpu; @@ -946,16 +1015,18 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) goto err_out_unregister; kobject_uevent(&policy->kobj, KOBJ_ADD); - module_put(cpufreq_driver->owner); + rcu_read_lock(); + module_put(rcu_dereference(cpufreq_driver)->owner); + rcu_read_unlock(); pr_debug("initialization complete\n"); return 0; err_out_unregister: - spin_lock_irqsave(&cpufreq_driver_lock, flags); + write_lock_irqsave(&cpufreq_driver_lock, flags); for_each_cpu(j, policy->cpus) per_cpu(cpufreq_cpu_data, j) = NULL; - spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + write_unlock_irqrestore(&cpufreq_driver_lock, flags); kobject_put(&policy->kobj); wait_for_completion(&policy->kobj_unregister); @@ -968,7 +1039,9 @@ err_free_cpumask: err_free_policy: kfree(policy); nomem_out: - module_put(cpufreq_driver->owner); + rcu_read_lock(); + module_put(rcu_dereference(cpufreq_driver)->owner); + rcu_read_unlock(); module_out: return ret; } @@ -1002,36 +1075,46 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif unsigned int cpu = dev->id, ret, cpus; unsigned long flags; struct cpufreq_policy *data; + struct cpufreq_driver *driver; struct kobject *kobj; struct completion *cmp; struct device *cpu_dev; + bool has_target; + int (*exit)(struct cpufreq_policy *policy); pr_debug("%s: unregistering CPU %u\n", __func__, cpu); - spin_lock_irqsave(&cpufreq_driver_lock, flags); + write_lock_irqsave(&cpufreq_driver_lock, flags); data = per_cpu(cpufreq_cpu_data, cpu); per_cpu(cpufreq_cpu_data, cpu) = NULL; - spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + write_unlock_irqrestore(&cpufreq_driver_lock, flags); if (!data) { pr_debug("%s: No cpu_data found\n", __func__); return -EINVAL; } - if (cpufreq_driver->target) + rcu_read_lock(); + driver = rcu_dereference(cpufreq_driver); + has_target = driver->target ? true : false; + exit = driver->exit; + if (has_target) __cpufreq_governor(data, CPUFREQ_GOV_STOP); #ifdef CONFIG_HOTPLUG_CPU - if (!cpufreq_driver->setpolicy) + if (!driver->setpolicy) strncpy(per_cpu(cpufreq_cpu_governor, cpu), data->governor->name, CPUFREQ_NAME_LEN); #endif + rcu_read_unlock(); WARN_ON(lock_policy_rwsem_write(cpu)); cpus = cpumask_weight(data->cpus); - cpumask_clear_cpu(cpu, data->cpus); + + if (cpus > 1) + cpumask_clear_cpu(cpu, data->cpus); unlock_policy_rwsem_write(cpu); if (cpu != data->cpu) { @@ -1047,9 +1130,9 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif WARN_ON(lock_policy_rwsem_write(cpu)); cpumask_set_cpu(cpu, data->cpus); - spin_lock_irqsave(&cpufreq_driver_lock, flags); + write_lock_irqsave(&cpufreq_driver_lock, flags); per_cpu(cpufreq_cpu_data, cpu) = data; - spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + write_unlock_irqrestore(&cpufreq_driver_lock, flags); unlock_policy_rwsem_write(cpu); @@ -1070,6 +1153,9 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif /* If cpu is last user of policy, free policy */ if (cpus == 1) { + if (has_target) + __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT); + lock_policy_rwsem_read(cpu); kobj = &data->kobj; cmp = &data->kobj_unregister; @@ -1084,13 +1170,13 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif wait_for_completion(cmp); pr_debug("wait complete\n"); - if (cpufreq_driver->exit) - cpufreq_driver->exit(data); + if (exit) + exit(data); free_cpumask_var(data->related_cpus); free_cpumask_var(data->cpus); kfree(data); - } else if (cpufreq_driver->target) { + } else if (has_target) { __cpufreq_governor(data, CPUFREQ_GOV_START); __cpufreq_governor(data, CPUFREQ_GOV_LIMITS); } @@ -1134,16 +1220,23 @@ static void handle_update(struct work_struct *work) static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, unsigned int new_freq) { + struct cpufreq_policy *policy; struct cpufreq_freqs freqs; + unsigned long flags; + pr_debug("Warning: CPU frequency out of sync: cpufreq and timing " "core thinks of %u, is %u kHz.\n", old_freq, new_freq); - freqs.cpu = cpu; freqs.old = old_freq; freqs.new = new_freq; - cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); - cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); + + read_lock_irqsave(&cpufreq_driver_lock, flags); + policy = per_cpu(cpufreq_cpu_data, cpu); + read_unlock_irqrestore(&cpufreq_driver_lock, flags); + + cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); + cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); } @@ -1157,10 +1250,18 @@ static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, unsigned int cpufreq_quick_get(unsigned int cpu) { struct cpufreq_policy *policy; + struct cpufreq_driver *driver; + unsigned int (*get)(unsigned int cpu); unsigned int ret_freq = 0; - if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) - return cpufreq_driver->get(cpu); + rcu_read_lock(); + driver = rcu_dereference(cpufreq_driver); + if (driver && driver->setpolicy && driver->get) { + get = driver->get; + rcu_read_unlock(); + return get(cpu); + } + rcu_read_unlock(); policy = cpufreq_cpu_get(cpu); if (policy) { @@ -1196,15 +1297,26 @@ EXPORT_SYMBOL(cpufreq_quick_get_max); static unsigned int __cpufreq_get(unsigned int cpu) { struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); + struct cpufreq_driver *driver; + unsigned int (*get)(unsigned int cpu); unsigned int ret_freq = 0; + u8 flags; + - if (!cpufreq_driver->get) + rcu_read_lock(); + driver = rcu_dereference(cpufreq_driver); + if (!driver->get) { + rcu_read_unlock(); return ret_freq; + } + flags = driver->flags; + get = driver->get; + rcu_read_unlock(); - ret_freq = cpufreq_driver->get(cpu); + ret_freq = get(cpu); if (ret_freq && policy->cur && - !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { + !(flags & CPUFREQ_CONST_LOOPS)) { /* verify no discrepancy between actual and saved value exists */ if (unlikely(ret_freq != policy->cur)) { @@ -1260,6 +1372,7 @@ static struct subsys_interface cpufreq_interface = { */ static int cpufreq_bp_suspend(void) { + int (*suspend)(struct cpufreq_policy *policy); int ret = 0; int cpu = smp_processor_id(); @@ -1272,8 +1385,11 @@ static int cpufreq_bp_suspend(void) if (!cpu_policy) return 0; - if (cpufreq_driver->suspend) { - ret = cpufreq_driver->suspend(cpu_policy); + rcu_read_lock(); + suspend = rcu_dereference(cpufreq_driver)->suspend; + rcu_read_unlock(); + if (suspend) { + ret = suspend(cpu_policy); if (ret) printk(KERN_ERR "cpufreq: suspend failed in ->suspend " "step on CPU %u\n", cpu_policy->cpu); @@ -1299,6 +1415,7 @@ static int cpufreq_bp_suspend(void) static void cpufreq_bp_resume(void) { int ret = 0; + int (*resume)(struct cpufreq_policy *policy); int cpu = smp_processor_id(); struct cpufreq_policy *cpu_policy; @@ -1310,8 +1427,12 @@ static void cpufreq_bp_resume(void) if (!cpu_policy) return; - if (cpufreq_driver->resume) { - ret = cpufreq_driver->resume(cpu_policy); + rcu_read_lock(); + resume = rcu_dereference(cpufreq_driver)->resume; + rcu_read_unlock(); + + if (resume) { + ret = resume(cpu_policy); if (ret) { printk(KERN_ERR "cpufreq: resume failed in ->resume " "step on CPU %u\n", cpu_policy->cpu); @@ -1338,10 +1459,14 @@ static struct syscore_ops cpufreq_syscore_ops = { */ const char *cpufreq_get_current_driver(void) { - if (cpufreq_driver) - return cpufreq_driver->name; - - return NULL; + struct cpufreq_driver *driver; + const char *name = NULL; + rcu_read_lock(); + driver = rcu_dereference(cpufreq_driver); + if (driver) + name = driver->name; + rcu_read_unlock(); + return name; } EXPORT_SYMBOL_GPL(cpufreq_get_current_driver); @@ -1435,6 +1560,9 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy, { int retval = -EINVAL; unsigned int old_target_freq = target_freq; + int (*target)(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation); if (cpufreq_disabled()) return -ENODEV; @@ -1451,8 +1579,11 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy, if (target_freq == policy->cur) return 0; - if (cpufreq_driver->target) - retval = cpufreq_driver->target(policy, target_freq, relation); + rcu_read_lock(); + target = rcu_dereference(cpufreq_driver)->target; + rcu_read_unlock(); + if (target) + retval = target(policy, target_freq, relation); return retval; } @@ -1485,18 +1616,24 @@ EXPORT_SYMBOL_GPL(cpufreq_driver_target); int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu) { int ret = 0; + unsigned int (*getavg)(struct cpufreq_policy *policy, + unsigned int cpu); if (cpufreq_disabled()) return ret; - if (!cpufreq_driver->getavg) + rcu_read_lock(); + getavg = rcu_dereference(cpufreq_driver)->getavg; + rcu_read_unlock(); + + if (!getavg) return 0; policy = cpufreq_cpu_get(policy->cpu); if (!policy) return -EINVAL; - ret = cpufreq_driver->getavg(policy, cpu); + ret = getavg(policy, cpu); cpufreq_cpu_put(policy); return ret; @@ -1544,10 +1681,12 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, policy->cpu, event); ret = policy->governor->governor(policy, event); - if (event == CPUFREQ_GOV_START) - policy->governor->initialized++; - else if (event == CPUFREQ_GOV_STOP) - policy->governor->initialized--; + if (!ret) { + if (event == CPUFREQ_GOV_POLICY_INIT) + policy->governor->initialized++; + else if (event == CPUFREQ_GOV_POLICY_EXIT) + policy->governor->initialized--; + } /* we keep one module reference alive for each CPU governed by this CPU */ @@ -1651,7 +1790,10 @@ EXPORT_SYMBOL(cpufreq_get_policy); static int __cpufreq_set_policy(struct cpufreq_policy *data, struct cpufreq_policy *policy) { - int ret = 0; + int ret = 0, failed = 1; + struct cpufreq_driver *driver; + int (*verify)(struct cpufreq_policy *policy); + int (*setpolicy)(struct cpufreq_policy *policy); pr_debug("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu, policy->min, policy->max); @@ -1665,7 +1807,13 @@ static int __cpufreq_set_policy(struct cpufreq_policy *data, } /* verify the cpu speed can be set within this limit */ - ret = cpufreq_driver->verify(policy); + rcu_read_lock(); + driver = rcu_dereference(cpufreq_driver); + verify = driver->verify; + setpolicy = driver->setpolicy; + rcu_read_unlock(); + + ret = verify(policy); if (ret) goto error_out; @@ -1679,7 +1827,7 @@ static int __cpufreq_set_policy(struct cpufreq_policy *data, /* verify the cpu speed can be set within this limit, which might be different to the first one */ - ret = cpufreq_driver->verify(policy); + ret = verify(policy); if (ret) goto error_out; @@ -1693,10 +1841,10 @@ static int __cpufreq_set_policy(struct cpufreq_policy *data, pr_debug("new min and max freqs are %u - %u kHz\n", data->min, data->max); - if (cpufreq_driver->setpolicy) { + if (setpolicy) { data->policy = policy->policy; pr_debug("setting range\n"); - ret = cpufreq_driver->setpolicy(policy); + ret = setpolicy(policy); } else { if (policy->governor != data->governor) { /* save old, working values */ @@ -1705,18 +1853,31 @@ static int __cpufreq_set_policy(struct cpufreq_policy *data, pr_debug("governor switch\n"); /* end old governor */ - if (data->governor) + if (data->governor) { __cpufreq_governor(data, CPUFREQ_GOV_STOP); + __cpufreq_governor(data, + CPUFREQ_GOV_POLICY_EXIT); + } /* start new governor */ data->governor = policy->governor; - if (__cpufreq_governor(data, CPUFREQ_GOV_START)) { + if (!__cpufreq_governor(data, CPUFREQ_GOV_POLICY_INIT)) { + if (!__cpufreq_governor(data, CPUFREQ_GOV_START)) + failed = 0; + else + __cpufreq_governor(data, + CPUFREQ_GOV_POLICY_EXIT); + } + + if (failed) { /* new governor failed, so re-start old one */ pr_debug("starting governor %s failed\n", data->governor->name); if (old_gov) { data->governor = old_gov; __cpufreq_governor(data, + CPUFREQ_GOV_POLICY_INIT); + __cpufreq_governor(data, CPUFREQ_GOV_START); } ret = -EINVAL; @@ -1743,6 +1904,11 @@ int cpufreq_update_policy(unsigned int cpu) { struct cpufreq_policy *data = cpufreq_cpu_get(cpu); struct cpufreq_policy policy; + struct cpufreq_driver *driver; + unsigned int (*get)(unsigned int cpu); + int (*target)(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation); int ret; if (!data) { @@ -1764,13 +1930,18 @@ int cpufreq_update_policy(unsigned int cpu) /* BIOS might change freq behind our back -> ask driver for current freq and notify governors about a change */ - if (cpufreq_driver->get) { - policy.cur = cpufreq_driver->get(cpu); + rcu_read_lock(); + driver = rcu_access_pointer(cpufreq_driver); + get = driver->get; + target = driver->target; + rcu_read_unlock(); + if (get) { + policy.cur = get(cpu); if (!data->cur) { pr_debug("Driver did not initialize current freq"); data->cur = policy.cur; } else { - if (data->cur != policy.cur && cpufreq_driver->target) + if (data->cur != policy.cur && target) cpufreq_out_of_sync(cpu, data->cur, policy.cur); } @@ -1848,19 +2019,20 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) if (driver_data->setpolicy) driver_data->flags |= CPUFREQ_CONST_LOOPS; - spin_lock_irqsave(&cpufreq_driver_lock, flags); - if (cpufreq_driver) { - spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + write_lock_irqsave(&cpufreq_driver_lock, flags); + if (rcu_access_pointer(cpufreq_driver)) { + write_unlock_irqrestore(&cpufreq_driver_lock, flags); return -EBUSY; } - cpufreq_driver = driver_data; - spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + rcu_assign_pointer(cpufreq_driver, driver_data); + write_unlock_irqrestore(&cpufreq_driver_lock, flags); + synchronize_rcu(); ret = subsys_interface_register(&cpufreq_interface); if (ret) goto err_null_driver; - if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) { + if (!(driver_data->flags & CPUFREQ_STICKY)) { int i; ret = -ENODEV; @@ -1886,9 +2058,10 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) err_if_unreg: subsys_interface_unregister(&cpufreq_interface); err_null_driver: - spin_lock_irqsave(&cpufreq_driver_lock, flags); - cpufreq_driver = NULL; - spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + write_lock_irqsave(&cpufreq_driver_lock, flags); + rcu_assign_pointer(cpufreq_driver, NULL); + write_unlock_irqrestore(&cpufreq_driver_lock, flags); + synchronize_rcu(); return ret; } EXPORT_SYMBOL_GPL(cpufreq_register_driver); @@ -1905,18 +2078,25 @@ EXPORT_SYMBOL_GPL(cpufreq_register_driver); int cpufreq_unregister_driver(struct cpufreq_driver *driver) { unsigned long flags; + struct cpufreq_driver *old_driver; - if (!cpufreq_driver || (driver != cpufreq_driver)) + rcu_read_lock(); + old_driver = rcu_access_pointer(cpufreq_driver); + if (!old_driver || (driver != old_driver)) { + rcu_read_unlock(); return -EINVAL; + } + rcu_read_unlock(); pr_debug("unregistering driver %s\n", driver->name); subsys_interface_unregister(&cpufreq_interface); unregister_hotcpu_notifier(&cpufreq_cpu_notifier); - spin_lock_irqsave(&cpufreq_driver_lock, flags); - cpufreq_driver = NULL; - spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + write_lock_irqsave(&cpufreq_driver_lock, flags); + rcu_assign_pointer(cpufreq_driver, NULL); + write_unlock_irqrestore(&cpufreq_driver_lock, flags); + synchronize_rcu(); return 0; } |