| /* |
| * cpuidle.c - core cpuidle infrastructure |
| * |
| * (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> |
| * Shaohua Li <shaohua.li@intel.com> |
| * Adam Belay <abelay@novell.com> |
| * |
| * This code is licenced under the GPL. |
| */ |
| |
| #include <linux/clockchips.h> |
| #include <linux/kernel.h> |
| #include <linux/mutex.h> |
| #include <linux/sched.h> |
| #include <linux/notifier.h> |
| #include <linux/pm_qos.h> |
| #include <linux/cpu.h> |
| #include <linux/cpuidle.h> |
| #include <linux/ktime.h> |
| #include <linux/hrtimer.h> |
| #include <linux/module.h> |
| |
| #include "cpuidle.h" |
| |
| DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices); |
| DEFINE_PER_CPU(struct cpuidle_device, cpuidle_dev); |
| |
| DEFINE_MUTEX(cpuidle_lock); |
| LIST_HEAD(cpuidle_detected_devices); |
| |
| static int enabled_devices; |
| static int off __read_mostly; |
| static int initialized __read_mostly; |
| |
| int cpuidle_disabled(void) |
| { |
| return off; |
| } |
| void disable_cpuidle(void) |
| { |
| off = 1; |
| } |
| |
| static int __cpuidle_register_device(struct cpuidle_device *dev); |
| |
| /** |
| * cpuidle_play_dead - cpu off-lining |
| * |
| * Returns in case of an error or no driver |
| */ |
| int cpuidle_play_dead(void) |
| { |
| struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); |
| struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
| int i; |
| |
| if (!drv) |
| return -ENODEV; |
| |
| /* Find lowest-power state that supports long-term idle */ |
| for (i = drv->state_count - 1; i >= CPUIDLE_DRIVER_STATE_START; i--) |
| if (drv->states[i].enter_dead) |
| return drv->states[i].enter_dead(dev, i); |
| |
| return -ENODEV; |
| } |
| |
| /** |
| * cpuidle_enter_state - enter the state and update stats |
| * @dev: cpuidle device for this cpu |
| * @drv: cpuidle driver for this cpu |
| * @next_state: index into drv->states of the state to enter |
| */ |
| int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, |
| int index) |
| { |
| int entered_state; |
| |
| struct cpuidle_state *target_state = &drv->states[index]; |
| ktime_t time_start, time_end; |
| s64 diff; |
| |
| time_start = ktime_get(); |
| |
| entered_state = target_state->enter(dev, drv, index); |
| |
| time_end = ktime_get(); |
| |
| local_irq_enable(); |
| |
| diff = ktime_to_us(ktime_sub(time_end, time_start)); |
| if (diff > INT_MAX) |
| diff = INT_MAX; |
| |
| dev->last_residency = (int) diff; |
| |
| if (entered_state >= 0) { |
| /* Update cpuidle counters */ |
| /* This can be moved to within driver enter routine |
| * but that results in multiple copies of same code. |
| */ |
| dev->states_usage[entered_state].time += dev->last_residency; |
| dev->states_usage[entered_state].usage++; |
| } else { |
| dev->last_residency = 0; |
| } |
| |
| return entered_state; |
| } |
| |
| /** |
| * cpuidle_idle_call - the main idle loop |
| * |
| * NOTE: no locks or semaphores should be used here |
| * return non-zero on failure |
| */ |
| int cpuidle_idle_call(void) |
| { |
| struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); |
| struct cpuidle_driver *drv; |
| int next_state, entered_state; |
| |
| if (off) |
| return -ENODEV; |
| |
| if (!initialized) |
| return -ENODEV; |
| |
| /* check if the device is ready */ |
| if (!dev || !dev->enabled) |
| return -EBUSY; |
| |
| drv = cpuidle_get_cpu_driver(dev); |
| |
| /* ask the governor for the next state */ |
| next_state = cpuidle_curr_governor->select(drv, dev); |
| if (need_resched()) { |
| dev->last_residency = 0; |
| /* give the governor an opportunity to reflect on the outcome */ |
| if (cpuidle_curr_governor->reflect) |
| cpuidle_curr_governor->reflect(dev, next_state); |
| local_irq_enable(); |
| return 0; |
| } |
| |
| if (drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP) |
| clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, |
| &dev->cpu); |
| |
| if (cpuidle_state_is_coupled(dev, drv, next_state)) |
| entered_state = cpuidle_enter_state_coupled(dev, drv, |
| next_state); |
| else |
| entered_state = cpuidle_enter_state(dev, drv, next_state); |
| |
| if (drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP) |
| clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, |
| &dev->cpu); |
| |
| /* give the governor an opportunity to reflect on the outcome */ |
| if (cpuidle_curr_governor->reflect) |
| cpuidle_curr_governor->reflect(dev, entered_state); |
| |
| return 0; |
| } |
| |
| /** |
| * cpuidle_install_idle_handler - installs the cpuidle idle loop handler |
| */ |
| void cpuidle_install_idle_handler(void) |
| { |
| if (enabled_devices) { |
| /* Make sure all changes finished before we switch to new idle */ |
| smp_wmb(); |
| initialized = 1; |
| } |
| } |
| |
| /** |
| * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler |
| */ |
| void cpuidle_uninstall_idle_handler(void) |
| { |
| if (enabled_devices) { |
| initialized = 0; |
| kick_all_cpus_sync(); |
| } |
| } |
| |
| /** |
| * cpuidle_pause_and_lock - temporarily disables CPUIDLE |
| */ |
| void cpuidle_pause_and_lock(void) |
| { |
| mutex_lock(&cpuidle_lock); |
| cpuidle_uninstall_idle_handler(); |
| } |
| |
| EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock); |
| |
| /** |
| * cpuidle_resume_and_unlock - resumes CPUIDLE operation |
| */ |
| void cpuidle_resume_and_unlock(void) |
| { |
| cpuidle_install_idle_handler(); |
| mutex_unlock(&cpuidle_lock); |
| } |
| |
| EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock); |
| |
| /* Currently used in suspend/resume path to suspend cpuidle */ |
| void cpuidle_pause(void) |
| { |
| mutex_lock(&cpuidle_lock); |
| cpuidle_uninstall_idle_handler(); |
| mutex_unlock(&cpuidle_lock); |
| } |
| |
| /* Currently used in suspend/resume path to resume cpuidle */ |
| void cpuidle_resume(void) |
| { |
| mutex_lock(&cpuidle_lock); |
| cpuidle_install_idle_handler(); |
| mutex_unlock(&cpuidle_lock); |
| } |
| |
| #ifdef CONFIG_ARCH_HAS_CPU_RELAX |
| static int poll_idle(struct cpuidle_device *dev, |
| struct cpuidle_driver *drv, int index) |
| { |
| ktime_t t1, t2; |
| s64 diff; |
| |
| t1 = ktime_get(); |
| local_irq_enable(); |
| while (!need_resched()) |
| cpu_relax(); |
| |
| t2 = ktime_get(); |
| diff = ktime_to_us(ktime_sub(t2, t1)); |
| if (diff > INT_MAX) |
| diff = INT_MAX; |
| |
| dev->last_residency = (int) diff; |
| |
| return index; |
| } |
| |
| static void poll_idle_init(struct cpuidle_driver *drv) |
| { |
| struct cpuidle_state *state = &drv->states[0]; |
| |
| snprintf(state->name, CPUIDLE_NAME_LEN, "POLL"); |
| snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE"); |
| state->exit_latency = 0; |
| state->target_residency = 0; |
| state->power_usage = -1; |
| state->flags = 0; |
| state->enter = poll_idle; |
| state->disabled = false; |
| } |
| #else |
| static void poll_idle_init(struct cpuidle_driver *drv) {} |
| #endif /* CONFIG_ARCH_HAS_CPU_RELAX */ |
| |
| /** |
| * cpuidle_enable_device - enables idle PM for a CPU |
| * @dev: the CPU |
| * |
| * This function must be called between cpuidle_pause_and_lock and |
| * cpuidle_resume_and_unlock when used externally. |
| */ |
| int cpuidle_enable_device(struct cpuidle_device *dev) |
| { |
| int ret, i; |
| struct cpuidle_driver *drv; |
| |
| if (!dev) |
| return -EINVAL; |
| |
| if (dev->enabled) |
| return 0; |
| |
| drv = cpuidle_get_cpu_driver(dev); |
| |
| if (!drv || !cpuidle_curr_governor) |
| return -EIO; |
| |
| if (!dev->state_count) |
| dev->state_count = drv->state_count; |
| |
| if (dev->registered == 0) { |
| ret = __cpuidle_register_device(dev); |
| if (ret) |
| return ret; |
| } |
| |
| poll_idle_init(drv); |
| |
| ret = cpuidle_add_device_sysfs(dev); |
| if (ret) |
| return ret; |
| |
| if (cpuidle_curr_governor->enable && |
| (ret = cpuidle_curr_governor->enable(drv, dev))) |
| goto fail_sysfs; |
| |
| for (i = 0; i < dev->state_count; i++) { |
| dev->states_usage[i].usage = 0; |
| dev->states_usage[i].time = 0; |
| } |
| dev->last_residency = 0; |
| |
| smp_wmb(); |
| |
| dev->enabled = 1; |
| |
| enabled_devices++; |
| return 0; |
| |
| fail_sysfs: |
| cpuidle_remove_device_sysfs(dev); |
| |
| return ret; |
| } |
| |
| EXPORT_SYMBOL_GPL(cpuidle_enable_device); |
| |
| /** |
| * cpuidle_disable_device - disables idle PM for a CPU |
| * @dev: the CPU |
| * |
| * This function must be called between cpuidle_pause_and_lock and |
| * cpuidle_resume_and_unlock when used externally. |
| */ |
| void cpuidle_disable_device(struct cpuidle_device *dev) |
| { |
| struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
| |
| if (!dev || !dev->enabled) |
| return; |
| |
| if (!drv || !cpuidle_curr_governor) |
| return; |
| |
| dev->enabled = 0; |
| |
| if (cpuidle_curr_governor->disable) |
| cpuidle_curr_governor->disable(drv, dev); |
| |
| cpuidle_remove_device_sysfs(dev); |
| enabled_devices--; |
| } |
| |
| EXPORT_SYMBOL_GPL(cpuidle_disable_device); |
| |
| /** |
| * __cpuidle_register_device - internal register function called before register |
| * and enable routines |
| * @dev: the cpu |
| * |
| * cpuidle_lock mutex must be held before this is called |
| */ |
| static int __cpuidle_register_device(struct cpuidle_device *dev) |
| { |
| int ret; |
| struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
| |
| if (!try_module_get(drv->owner)) |
| return -EINVAL; |
| |
| per_cpu(cpuidle_devices, dev->cpu) = dev; |
| list_add(&dev->device_list, &cpuidle_detected_devices); |
| ret = cpuidle_add_sysfs(dev); |
| if (ret) |
| goto err_sysfs; |
| |
| ret = cpuidle_coupled_register_device(dev); |
| if (ret) |
| goto err_coupled; |
| |
| dev->registered = 1; |
| return 0; |
| |
| err_coupled: |
| cpuidle_remove_sysfs(dev); |
| err_sysfs: |
| list_del(&dev->device_list); |
| per_cpu(cpuidle_devices, dev->cpu) = NULL; |
| module_put(drv->owner); |
| return ret; |
| } |
| |
| /** |
| * cpuidle_register_device - registers a CPU's idle PM feature |
| * @dev: the cpu |
| */ |
| int cpuidle_register_device(struct cpuidle_device *dev) |
| { |
| int ret; |
| |
| if (!dev) |
| return -EINVAL; |
| |
| mutex_lock(&cpuidle_lock); |
| |
| if ((ret = __cpuidle_register_device(dev))) { |
| mutex_unlock(&cpuidle_lock); |
| return ret; |
| } |
| |
| cpuidle_enable_device(dev); |
| cpuidle_install_idle_handler(); |
| |
| mutex_unlock(&cpuidle_lock); |
| |
| return 0; |
| |
| } |
| |
| EXPORT_SYMBOL_GPL(cpuidle_register_device); |
| |
| /** |
| * cpuidle_unregister_device - unregisters a CPU's idle PM feature |
| * @dev: the cpu |
| */ |
| void cpuidle_unregister_device(struct cpuidle_device *dev) |
| { |
| struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
| |
| if (dev->registered == 0) |
| return; |
| |
| cpuidle_pause_and_lock(); |
| |
| cpuidle_disable_device(dev); |
| |
| cpuidle_remove_sysfs(dev); |
| list_del(&dev->device_list); |
| per_cpu(cpuidle_devices, dev->cpu) = NULL; |
| |
| cpuidle_coupled_unregister_device(dev); |
| |
| cpuidle_resume_and_unlock(); |
| |
| module_put(drv->owner); |
| } |
| |
| EXPORT_SYMBOL_GPL(cpuidle_unregister_device); |
| |
| /** |
| * cpuidle_unregister: unregister a driver and the devices. This function |
| * can be used only if the driver has been previously registered through |
| * the cpuidle_register function. |
| * |
| * @drv: a valid pointer to a struct cpuidle_driver |
| */ |
| void cpuidle_unregister(struct cpuidle_driver *drv) |
| { |
| int cpu; |
| struct cpuidle_device *device; |
| |
| for_each_possible_cpu(cpu) { |
| device = &per_cpu(cpuidle_dev, cpu); |
| cpuidle_unregister_device(device); |
| } |
| |
| cpuidle_unregister_driver(drv); |
| } |
| EXPORT_SYMBOL_GPL(cpuidle_unregister); |
| |
| /** |
| * cpuidle_register: registers the driver and the cpu devices with the |
| * coupled_cpus passed as parameter. This function is used for all common |
| * initialization pattern there are in the arch specific drivers. The |
| * devices is globally defined in this file. |
| * |
| * @drv : a valid pointer to a struct cpuidle_driver |
| * @coupled_cpus: a cpumask for the coupled states |
| * |
| * Returns 0 on success, < 0 otherwise |
| */ |
| int cpuidle_register(struct cpuidle_driver *drv, |
| const struct cpumask *const coupled_cpus) |
| { |
| int ret, cpu; |
| struct cpuidle_device *device; |
| |
| ret = cpuidle_register_driver(drv); |
| if (ret) { |
| pr_err("failed to register cpuidle driver\n"); |
| return ret; |
| } |
| |
| for_each_possible_cpu(cpu) { |
| device = &per_cpu(cpuidle_dev, cpu); |
| device->cpu = cpu; |
| |
| #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED |
| /* |
| * On multiplatform for ARM, the coupled idle states could |
| * enabled in the kernel even if the cpuidle driver does not |
| * use it. Note, coupled_cpus is a struct copy. |
| */ |
| if (coupled_cpus) |
| device->coupled_cpus = *coupled_cpus; |
| #endif |
| ret = cpuidle_register_device(device); |
| if (!ret) |
| continue; |
| |
| pr_err("Failed to register cpuidle device for cpu%d\n", cpu); |
| |
| cpuidle_unregister(drv); |
| break; |
| } |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(cpuidle_register); |
| |
| #ifdef CONFIG_SMP |
| |
| static void smp_callback(void *v) |
| { |
| /* we already woke the CPU up, nothing more to do */ |
| } |
| |
| /* |
| * This function gets called when a part of the kernel has a new latency |
| * requirement. This means we need to get all processors out of their C-state, |
| * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that |
| * wakes them all right up. |
| */ |
| static int cpuidle_latency_notify(struct notifier_block *b, |
| unsigned long l, void *v) |
| { |
| const struct cpumask *cpus; |
| |
| cpus = v ?: cpu_online_mask; |
| |
| preempt_disable(); |
| smp_call_function_many(cpus, smp_callback, NULL, 1); |
| preempt_enable(); |
| |
| return NOTIFY_OK; |
| } |
| |
| static struct notifier_block cpuidle_latency_notifier = { |
| .notifier_call = cpuidle_latency_notify, |
| }; |
| |
| static inline void latency_notifier_init(struct notifier_block *n) |
| { |
| pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n); |
| } |
| |
| #else /* CONFIG_SMP */ |
| |
| #define latency_notifier_init(x) do { } while (0) |
| |
| #endif /* CONFIG_SMP */ |
| |
| /** |
| * cpuidle_init - core initializer |
| */ |
| static int __init cpuidle_init(void) |
| { |
| int ret; |
| |
| if (cpuidle_disabled()) |
| return -ENODEV; |
| |
| ret = cpuidle_add_interface(cpu_subsys.dev_root); |
| if (ret) |
| return ret; |
| |
| latency_notifier_init(&cpuidle_latency_notifier); |
| |
| return 0; |
| } |
| |
| module_param(off, int, 0444); |
| core_initcall(cpuidle_init); |