diff options
Diffstat (limited to 'drivers/cpufreq/cpufreq.c')
-rw-r--r-- | drivers/cpufreq/cpufreq.c | 322 |
1 files changed, 175 insertions, 147 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 04548f7023a..02d534da22d 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -47,49 +47,11 @@ static LIST_HEAD(cpufreq_policy_list); static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor); #endif -/* - * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure - * all cpufreq/hotplug/workqueue/etc related lock issues. - * - * The rules for this semaphore: - * - Any routine that wants to read from the policy structure will - * do a down_read on this semaphore. - * - Any routine that will write to the policy structure and/or may take away - * the policy altogether (eg. CPU hotplug), will hold this lock in write - * mode before doing so. - * - * Additional rules: - * - Governor routines that can be called in cpufreq hotplug path should not - * take this sem as top level hotplug notifier handler takes this. - * - Lock should not be held across - * __cpufreq_governor(data, CPUFREQ_GOV_STOP); - */ -static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem); - -#define lock_policy_rwsem(mode, cpu) \ -static int lock_policy_rwsem_##mode(int cpu) \ -{ \ - struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); \ - BUG_ON(!policy); \ - down_##mode(&per_cpu(cpu_policy_rwsem, policy->cpu)); \ - \ - return 0; \ -} - -lock_policy_rwsem(read, cpu); -lock_policy_rwsem(write, cpu); - -#define unlock_policy_rwsem(mode, cpu) \ -static void unlock_policy_rwsem_##mode(int cpu) \ -{ \ - struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); \ - BUG_ON(!policy); \ - up_##mode(&per_cpu(cpu_policy_rwsem, policy->cpu)); \ +static inline bool has_target(void) +{ + return cpufreq_driver->target_index || cpufreq_driver->target; } -unlock_policy_rwsem(read, cpu); -unlock_policy_rwsem(write, cpu); - /* * rwsem to guarantee that cpufreq driver module doesn't unload during critical * sections @@ -135,7 +97,7 @@ static DEFINE_MUTEX(cpufreq_governor_mutex); bool have_governor_per_policy(void) { - return cpufreq_driver->have_governor_per_policy; + return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY); } EXPORT_SYMBOL_GPL(have_governor_per_policy); @@ -183,6 +145,37 @@ u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy) } EXPORT_SYMBOL_GPL(get_cpu_idle_time); +/* + * This is a generic cpufreq init() routine which can be used by cpufreq + * drivers of SMP systems. It will do following: + * - validate & show freq table passed + * - set policies transition latency + * - policy->cpus with all possible CPUs + */ +int cpufreq_generic_init(struct cpufreq_policy *policy, + struct cpufreq_frequency_table *table, + unsigned int transition_latency) +{ + int ret; + + ret = cpufreq_table_validate_and_show(policy, table); + if (ret) { + pr_err("%s: invalid frequency table: %d\n", __func__, ret); + return ret; + } + + policy->cpuinfo.transition_latency = transition_latency; + + /* + * The driver only supports the SMP configuartion where all processors + * share the clock and voltage and clock. + */ + cpumask_setall(policy->cpus); + + return 0; +} +EXPORT_SYMBOL_GPL(cpufreq_generic_init); + struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu) { struct cpufreq_policy *policy = NULL; @@ -363,7 +356,7 @@ 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); @@ -414,7 +407,7 @@ show_one(scaling_min_freq, min); show_one(scaling_max_freq, max); show_one(scaling_cur_freq, cur); -static int __cpufreq_set_policy(struct cpufreq_policy *policy, +static int cpufreq_set_policy(struct cpufreq_policy *policy, struct cpufreq_policy *new_policy); /** @@ -435,7 +428,7 @@ static ssize_t store_##file_name \ if (ret != 1) \ return -EINVAL; \ \ - ret = __cpufreq_set_policy(policy, &new_policy); \ + ret = cpufreq_set_policy(policy, &new_policy); \ policy->user_policy.object = policy->object; \ \ return ret ? ret : count; \ @@ -493,11 +486,7 @@ static ssize_t store_scaling_governor(struct cpufreq_policy *policy, &new_policy.governor)) return -EINVAL; - /* - * Do not use cpufreq_set_policy here or the user_policy.max - * will be wrongly overridden - */ - ret = __cpufreq_set_policy(policy, &new_policy); + ret = cpufreq_set_policy(policy, &new_policy); policy->user_policy.policy = policy->policy; policy->user_policy.governor = policy->governor; @@ -525,7 +514,7 @@ static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy, ssize_t i = 0; struct cpufreq_governor *t; - if (!cpufreq_driver->target) { + if (!has_target()) { i += sprintf(buf, "performance powersave"); goto out; } @@ -653,24 +642,21 @@ static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf) { struct cpufreq_policy *policy = to_policy(kobj); struct freq_attr *fattr = to_attr(attr); - ssize_t ret = -EINVAL; + ssize_t ret; if (!down_read_trylock(&cpufreq_rwsem)) - goto exit; + return -EINVAL; - if (lock_policy_rwsem_read(policy->cpu) < 0) - goto up_read; + down_read(&policy->rwsem); if (fattr->show) ret = fattr->show(policy, buf); else ret = -EIO; - unlock_policy_rwsem_read(policy->cpu); - -up_read: + up_read(&policy->rwsem); up_read(&cpufreq_rwsem); -exit: + return ret; } @@ -689,17 +675,15 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr, if (!down_read_trylock(&cpufreq_rwsem)) goto unlock; - if (lock_policy_rwsem_write(policy->cpu) < 0) - goto up_read; + down_write(&policy->rwsem); if (fattr->store) ret = fattr->store(policy, buf, count); else ret = -EIO; - unlock_policy_rwsem_write(policy->cpu); + up_write(&policy->rwsem); -up_read: up_read(&cpufreq_rwsem); unlock: put_online_cpus(); @@ -815,7 +799,7 @@ static int cpufreq_add_dev_interface(struct cpufreq_policy *policy, if (ret) goto err_out_kobj_put; } - if (cpufreq_driver->target) { + if (has_target()) { ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr); if (ret) goto err_out_kobj_put; @@ -844,11 +828,11 @@ static void cpufreq_init_policy(struct cpufreq_policy *policy) int ret = 0; memcpy(&new_policy, policy, sizeof(*policy)); - /* assure that the starting sequence is run in __cpufreq_set_policy */ + /* assure that the starting sequence is run in cpufreq_set_policy */ policy->governor = NULL; /* set default policy */ - ret = __cpufreq_set_policy(policy, &new_policy); + ret = cpufreq_set_policy(policy, &new_policy); policy->user_policy.policy = policy->policy; policy->user_policy.governor = policy->governor; @@ -864,10 +848,10 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu, struct device *dev, bool frozen) { - int ret = 0, has_target = !!cpufreq_driver->target; + int ret = 0; unsigned long flags; - if (has_target) { + if (has_target()) { ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP); if (ret) { pr_err("%s: Failed to stop governor\n", __func__); @@ -875,7 +859,7 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, } } - lock_policy_rwsem_write(policy->cpu); + down_write(&policy->rwsem); write_lock_irqsave(&cpufreq_driver_lock, flags); @@ -883,9 +867,9 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, per_cpu(cpufreq_cpu_data, cpu) = policy; write_unlock_irqrestore(&cpufreq_driver_lock, flags); - unlock_policy_rwsem_write(policy->cpu); + up_write(&policy->rwsem); - if (has_target) { + if (has_target()) { if ((ret = __cpufreq_governor(policy, CPUFREQ_GOV_START)) || (ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))) { pr_err("%s: Failed to start governor\n", __func__); @@ -930,6 +914,8 @@ static struct cpufreq_policy *cpufreq_policy_alloc(void) goto err_free_cpumask; INIT_LIST_HEAD(&policy->policy_list); + init_rwsem(&policy->rwsem); + return policy; err_free_cpumask: @@ -949,26 +935,17 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy) static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu) { - if (cpu == policy->cpu) + if (WARN_ON(cpu == policy->cpu)) return; - /* - * Take direct locks as lock_policy_rwsem_write wouldn't work here. - * Also lock for last cpu is enough here as contention will happen only - * after policy->cpu is changed and after it is changed, other threads - * will try to acquire lock for new cpu. And policy is already updated - * by then. - */ - down_write(&per_cpu(cpu_policy_rwsem, policy->cpu)); + down_write(&policy->rwsem); policy->last_cpu = policy->cpu; policy->cpu = cpu; - up_write(&per_cpu(cpu_policy_rwsem, policy->last_cpu)); + up_write(&policy->rwsem); -#ifdef CONFIG_CPU_FREQ_TABLE cpufreq_frequency_table_update_policy_cpu(policy); -#endif blocking_notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_UPDATE_POLICY_CPU, policy); } @@ -1053,6 +1030,14 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, goto err_set_policy_cpu; } + if (cpufreq_driver->get) { + policy->cur = cpufreq_driver->get(policy->cpu); + if (!policy->cur) { + pr_err("%s: ->get() failed\n", __func__); + goto err_get_freq; + } + } + /* related cpus should atleast have policy->cpus */ cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus); @@ -1107,6 +1092,9 @@ err_out_unregister: per_cpu(cpufreq_cpu_data, j) = NULL; write_unlock_irqrestore(&cpufreq_driver_lock, flags); +err_get_freq: + if (cpufreq_driver->exit) + cpufreq_driver->exit(policy); err_set_policy_cpu: cpufreq_policy_free(policy); nomem_out: @@ -1147,9 +1135,9 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy, if (ret) { pr_err("%s: Failed to move kobj: %d", __func__, ret); - WARN_ON(lock_policy_rwsem_write(old_cpu)); + down_write(&policy->rwsem); cpumask_set_cpu(old_cpu, policy->cpus); - unlock_policy_rwsem_write(old_cpu); + up_write(&policy->rwsem); ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj, "cpufreq"); @@ -1186,7 +1174,7 @@ static int __cpufreq_remove_dev_prepare(struct device *dev, return -EINVAL; } - if (cpufreq_driver->target) { + if (has_target()) { ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP); if (ret) { pr_err("%s: Failed to stop governor\n", __func__); @@ -1200,22 +1188,21 @@ static int __cpufreq_remove_dev_prepare(struct device *dev, policy->governor->name, CPUFREQ_NAME_LEN); #endif - lock_policy_rwsem_read(cpu); + down_read(&policy->rwsem); cpus = cpumask_weight(policy->cpus); - unlock_policy_rwsem_read(cpu); + up_read(&policy->rwsem); if (cpu != policy->cpu) { if (!frozen) sysfs_remove_link(&dev->kobj, "cpufreq"); } else if (cpus > 1) { - new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu, frozen); if (new_cpu >= 0) { update_policy_cpu(policy, new_cpu); if (!frozen) { - pr_debug("%s: policy Kobject moved to cpu: %d " - "from: %d\n",__func__, new_cpu, cpu); + pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n", + __func__, new_cpu, cpu); } } } @@ -1243,16 +1230,16 @@ static int __cpufreq_remove_dev_finish(struct device *dev, return -EINVAL; } - WARN_ON(lock_policy_rwsem_write(cpu)); + down_write(&policy->rwsem); cpus = cpumask_weight(policy->cpus); if (cpus > 1) cpumask_clear_cpu(cpu, policy->cpus); - unlock_policy_rwsem_write(cpu); + up_write(&policy->rwsem); /* If cpu is last user of policy, free policy */ if (cpus == 1) { - if (cpufreq_driver->target) { + if (has_target()) { ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); if (ret) { @@ -1263,10 +1250,10 @@ static int __cpufreq_remove_dev_finish(struct device *dev, } if (!frozen) { - lock_policy_rwsem_read(cpu); + down_read(&policy->rwsem); kobj = &policy->kobj; cmp = &policy->kobj_unregister; - unlock_policy_rwsem_read(cpu); + up_read(&policy->rwsem); kobject_put(kobj); /* @@ -1295,7 +1282,7 @@ static int __cpufreq_remove_dev_finish(struct device *dev, if (!frozen) cpufreq_policy_free(policy); } else { - if (cpufreq_driver->target) { + if (has_target()) { if ((ret = __cpufreq_governor(policy, CPUFREQ_GOV_START)) || (ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))) { pr_err("%s: Failed to start governor\n", @@ -1310,36 +1297,24 @@ static int __cpufreq_remove_dev_finish(struct device *dev, } /** - * __cpufreq_remove_dev - remove a CPU device + * cpufreq_remove_dev - remove a CPU device * * Removes the cpufreq interface for a CPU device. - * Caller should already have policy_rwsem in write mode for this CPU. - * This routine frees the rwsem before returning. */ -static inline int __cpufreq_remove_dev(struct device *dev, - struct subsys_interface *sif, - bool frozen) -{ - int ret; - - ret = __cpufreq_remove_dev_prepare(dev, sif, frozen); - - if (!ret) - ret = __cpufreq_remove_dev_finish(dev, sif, frozen); - - return ret; -} - static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) { unsigned int cpu = dev->id; - int retval; + int ret; if (cpu_is_offline(cpu)) return 0; - retval = __cpufreq_remove_dev(dev, sif, false); - return retval; + ret = __cpufreq_remove_dev_prepare(dev, sif, false); + + if (!ret) + ret = __cpufreq_remove_dev_finish(dev, sif, false); + + return ret; } static void handle_update(struct work_struct *work) @@ -1458,22 +1433,22 @@ static unsigned int __cpufreq_get(unsigned int cpu) */ unsigned int cpufreq_get(unsigned int cpu) { + struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); unsigned int ret_freq = 0; if (cpufreq_disabled() || !cpufreq_driver) return -ENOENT; + BUG_ON(!policy); + if (!down_read_trylock(&cpufreq_rwsem)) return 0; - if (unlikely(lock_policy_rwsem_read(cpu))) - goto out_policy; + down_read(&policy->rwsem); ret_freq = __cpufreq_get(cpu); - unlock_policy_rwsem_read(cpu); - -out_policy: + up_read(&policy->rwsem); up_read(&cpufreq_rwsem); return ret_freq; @@ -1681,12 +1656,75 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy, pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n", policy->cpu, target_freq, relation, old_target_freq); + /* + * This might look like a redundant call as we are checking it again + * after finding index. But it is left intentionally for cases where + * exactly same freq is called again and so we can save on few function + * calls. + */ if (target_freq == policy->cur) return 0; if (cpufreq_driver->target) retval = cpufreq_driver->target(policy, target_freq, relation); + else if (cpufreq_driver->target_index) { + struct cpufreq_frequency_table *freq_table; + struct cpufreq_freqs freqs; + bool notify; + int index; + + freq_table = cpufreq_frequency_get_table(policy->cpu); + if (unlikely(!freq_table)) { + pr_err("%s: Unable to find freq_table\n", __func__); + goto out; + } + + retval = cpufreq_frequency_table_target(policy, freq_table, + target_freq, relation, &index); + if (unlikely(retval)) { + pr_err("%s: Unable to find matching freq\n", __func__); + goto out; + } + + if (freq_table[index].frequency == policy->cur) { + retval = 0; + goto out; + } + + notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION); + + if (notify) { + freqs.old = policy->cur; + freqs.new = freq_table[index].frequency; + freqs.flags = 0; + + pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n", + __func__, policy->cpu, freqs.old, + freqs.new); + + cpufreq_notify_transition(policy, &freqs, + CPUFREQ_PRECHANGE); + } + + retval = cpufreq_driver->target_index(policy, index); + if (retval) + pr_err("%s: Failed to change cpu frequency: %d\n", + __func__, retval); + + if (notify) { + /* + * Notify with old freq in case we failed to change + * frequency + */ + if (retval) + freqs.new = freqs.old; + + cpufreq_notify_transition(policy, &freqs, + CPUFREQ_POSTCHANGE); + } + } +out: return retval; } EXPORT_SYMBOL_GPL(__cpufreq_driver_target); @@ -1697,14 +1735,12 @@ int cpufreq_driver_target(struct cpufreq_policy *policy, { int ret = -EINVAL; - if (unlikely(lock_policy_rwsem_write(policy->cpu))) - goto fail; + down_write(&policy->rwsem); ret = __cpufreq_driver_target(policy, target_freq, relation); - unlock_policy_rwsem_write(policy->cpu); + up_write(&policy->rwsem); -fail: return ret; } EXPORT_SYMBOL_GPL(cpufreq_driver_target); @@ -1871,10 +1907,10 @@ int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu) EXPORT_SYMBOL(cpufreq_get_policy); /* - * data : current policy. - * policy : policy to be set. + * policy : current policy. + * new_policy: policy to be set. */ -static int __cpufreq_set_policy(struct cpufreq_policy *policy, +static int cpufreq_set_policy(struct cpufreq_policy *policy, struct cpufreq_policy *new_policy) { int ret = 0, failed = 1; @@ -1934,10 +1970,10 @@ static int __cpufreq_set_policy(struct cpufreq_policy *policy, /* end old governor */ if (policy->governor) { __cpufreq_governor(policy, CPUFREQ_GOV_STOP); - unlock_policy_rwsem_write(new_policy->cpu); + up_write(&policy->rwsem); __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); - lock_policy_rwsem_write(new_policy->cpu); + down_write(&policy->rwsem); } /* start new governor */ @@ -1946,10 +1982,10 @@ static int __cpufreq_set_policy(struct cpufreq_policy *policy, if (!__cpufreq_governor(policy, CPUFREQ_GOV_START)) { failed = 0; } else { - unlock_policy_rwsem_write(new_policy->cpu); + up_write(&policy->rwsem); __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); - lock_policy_rwsem_write(new_policy->cpu); + down_write(&policy->rwsem); } } @@ -1995,10 +2031,7 @@ int cpufreq_update_policy(unsigned int cpu) goto no_policy; } - if (unlikely(lock_policy_rwsem_write(cpu))) { - ret = -EINVAL; - goto fail; - } + down_write(&policy->rwsem); pr_debug("updating policy for CPU %u\n", cpu); memcpy(&new_policy, policy, sizeof(*policy)); @@ -2017,17 +2050,16 @@ int cpufreq_update_policy(unsigned int cpu) pr_debug("Driver did not initialize current freq"); policy->cur = new_policy.cur; } else { - if (policy->cur != new_policy.cur && cpufreq_driver->target) + if (policy->cur != new_policy.cur && has_target()) cpufreq_out_of_sync(cpu, policy->cur, new_policy.cur); } } - ret = __cpufreq_set_policy(policy, &new_policy); + ret = cpufreq_set_policy(policy, &new_policy); - unlock_policy_rwsem_write(cpu); + up_write(&policy->rwsem); -fail: cpufreq_cpu_put(policy); no_policy: return ret; @@ -2096,7 +2128,8 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) return -ENODEV; if (!driver_data || !driver_data->verify || !driver_data->init || - ((!driver_data->setpolicy) && (!driver_data->target))) + !(driver_data->setpolicy || driver_data->target_index || + driver_data->target)) return -EINVAL; pr_debug("trying to register driver %s\n", driver_data->name); @@ -2183,14 +2216,9 @@ EXPORT_SYMBOL_GPL(cpufreq_unregister_driver); static int __init cpufreq_core_init(void) { - int cpu; - if (cpufreq_disabled()) return -ENODEV; - for_each_possible_cpu(cpu) - init_rwsem(&per_cpu(cpu_policy_rwsem, cpu)); - cpufreq_global_kobject = kobject_create(); BUG_ON(!cpufreq_global_kobject); register_syscore_ops(&cpufreq_syscore_ops); |