From cbc9ef0287ab764d3da0129efa673808df641fe3 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 3 Jul 2012 19:07:42 +0200 Subject: PM / Domains: Add preliminary support for cpuidle, v2 On some systems there are CPU cores located in the same power domains as I/O devices. Then, power can only be removed from the domain if all I/O devices in it are not in use and the CPU core is idle. Add preliminary support for that to the generic PM domains framework. First, the platform is expected to provide a cpuidle driver with one extra state designated for use with the generic PM domains code. This state should be initially disabled and its exit_latency value should be set to whatever time is needed to bring up the CPU core itself after restoring power to it, not including the domain's power on latency. Its .enter() callback should point to a procedure that will remove power from the domain containing the CPU core at the end of the CPU power transition. The remaining characteristics of the extra cpuidle state, referred to as the "domain" cpuidle state below, (e.g. power usage, target residency) should be populated in accordance with the properties of the hardware. Next, the platform should execute genpd_attach_cpuidle() on the PM domain containing the CPU core. That will cause the generic PM domains framework to treat that domain in a special way such that: * When all devices in the domain have been suspended and it is about to be turned off, the states of the devices will be saved, but power will not be removed from the domain. Instead, the "domain" cpuidle state will be enabled so that power can be removed from the domain when the CPU core is idle and the state has been chosen as the target by the cpuidle governor. * When the first I/O device in the domain is resumed and __pm_genpd_poweron(() is called for the first time after power has been removed from the domain, the "domain" cpuidle state will be disabled to avoid subsequent surprise power removals via cpuidle. The effective exit_latency value of the "domain" cpuidle state depends on the time needed to bring up the CPU core itself after restoring power to it as well as on the power on latency of the domain containing the CPU core. Thus the "domain" cpuidle state's exit_latency has to be recomputed every time the domain's power on latency is updated, which may happen every time power is restored to the domain, if the measured power on latency is greater than the latency stored in the corresponding generic_pm_domain structure. Signed-off-by: Rafael J. Wysocki Reviewed-by: Kevin Hilman --- include/linux/pm_domain.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'include/linux/pm_domain.h') diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h index 30f794eb382..2febe31d267 100644 --- a/include/linux/pm_domain.h +++ b/include/linux/pm_domain.h @@ -15,6 +15,7 @@ #include #include #include +#include enum gpd_status { GPD_STATE_ACTIVE = 0, /* PM domain is active */ @@ -45,6 +46,11 @@ struct gpd_dev_ops { bool (*active_wakeup)(struct device *dev); }; +struct gpd_cpu_data { + unsigned int saved_exit_latency; + struct cpuidle_state *idle_state; +}; + struct generic_pm_domain { struct dev_pm_domain domain; /* PM domain operations */ struct list_head gpd_list_node; /* Node in the global PM domains list */ @@ -75,6 +81,7 @@ struct generic_pm_domain { bool max_off_time_changed; bool cached_power_down_ok; struct device_node *of_node; /* Node in device tree */ + struct gpd_cpu_data *cpu_data; }; static inline struct generic_pm_domain *pd_to_genpd(struct dev_pm_domain *pd) @@ -155,6 +162,8 @@ extern int pm_genpd_add_callbacks(struct device *dev, struct gpd_dev_ops *ops, struct gpd_timing_data *td); extern int __pm_genpd_remove_callbacks(struct device *dev, bool clear_td); +extern int genpd_attach_cpuidle(struct generic_pm_domain *genpd, int state); +extern int genpd_detach_cpuidle(struct generic_pm_domain *genpd); extern void pm_genpd_init(struct generic_pm_domain *genpd, struct dev_power_governor *gov, bool is_off); @@ -211,6 +220,14 @@ static inline int __pm_genpd_remove_callbacks(struct device *dev, bool clear_td) { return -ENOSYS; } +static inline int genpd_attach_cpuidle(struct generic_pm_domain *genpd, int st) +{ + return -ENOSYS; +} +static inline int genpd_detach_cpuidle(struct generic_pm_domain *genpd) +{ + return -ENOSYS; +} static inline void pm_genpd_init(struct generic_pm_domain *genpd, struct dev_power_governor *gov, bool is_off) { -- cgit v1.2.3-70-g09d2 From 1d5fcfec22ce5f69db0d29284d2b65ff8ab1bfaa Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 5 Jul 2012 22:12:32 +0200 Subject: PM / Domains: Add device domain data reference counter Add a mechanism for counting references to the struct generic_pm_domain_data object pointed to by dev->power.subsys_data->domain_data if the device in question belongs to a generic PM domain. This change is necessary for a subsequent patch making it possible to allocate that object from within pm_genpd_add_callbacks(), so that drivers can attach their PM domain device callbacks to devices before those devices are added to PM domains. This patch has been tested on the SH7372 Mackerel board. Signed-off-by: Rafael J. Wysocki --- drivers/base/power/domain.c | 83 +++++++++++++++++++++++++++++++-------------- include/linux/pm_domain.h | 1 + 2 files changed, 58 insertions(+), 26 deletions(-) (limited to 'include/linux/pm_domain.h') diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c index 4b5f090fccb..45eb3b155b6 100644 --- a/drivers/base/power/domain.c +++ b/drivers/base/power/domain.c @@ -297,7 +297,7 @@ static int genpd_dev_pm_qos_notifier(struct notifier_block *nb, pdd = dev->power.subsys_data ? dev->power.subsys_data->domain_data : NULL; - if (pdd) { + if (pdd && pdd->dev) { to_gpd_data(pdd)->td.constraint_changed = true; genpd = dev_to_genpd(dev); } else { @@ -1266,6 +1266,27 @@ static void pm_genpd_complete(struct device *dev) #endif /* CONFIG_PM_SLEEP */ +static struct generic_pm_domain_data *__pm_genpd_alloc_dev_data(struct device *dev) +{ + struct generic_pm_domain_data *gpd_data; + + gpd_data = kzalloc(sizeof(*gpd_data), GFP_KERNEL); + if (!gpd_data) + return NULL; + + mutex_init(&gpd_data->lock); + gpd_data->nb.notifier_call = genpd_dev_pm_qos_notifier; + dev_pm_qos_add_notifier(dev, &gpd_data->nb); + return gpd_data; +} + +static void __pm_genpd_free_dev_data(struct device *dev, + struct generic_pm_domain_data *gpd_data) +{ + dev_pm_qos_remove_notifier(dev, &gpd_data->nb); + kfree(gpd_data); +} + /** * __pm_genpd_add_device - Add a device to an I/O PM domain. * @genpd: PM domain to add the device to. @@ -1275,7 +1296,7 @@ static void pm_genpd_complete(struct device *dev) int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev, struct gpd_timing_data *td) { - struct generic_pm_domain_data *gpd_data; + struct generic_pm_domain_data *gpd_data_new, *gpd_data = NULL; struct pm_domain_data *pdd; int ret = 0; @@ -1284,14 +1305,10 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev, if (IS_ERR_OR_NULL(genpd) || IS_ERR_OR_NULL(dev)) return -EINVAL; - gpd_data = kzalloc(sizeof(*gpd_data), GFP_KERNEL); - if (!gpd_data) + gpd_data_new = __pm_genpd_alloc_dev_data(dev); + if (!gpd_data_new) return -ENOMEM; - mutex_init(&gpd_data->lock); - gpd_data->nb.notifier_call = genpd_dev_pm_qos_notifier; - dev_pm_qos_add_notifier(dev, &gpd_data->nb); - genpd_acquire_lock(genpd); if (genpd->prepared_count > 0) { @@ -1305,35 +1322,42 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev, goto out; } + ret = dev_pm_get_subsys_data(dev); + if (ret) + goto out; + genpd->device_count++; genpd->max_off_time_changed = true; - dev_pm_get_subsys_data(dev); - - mutex_lock(&gpd_data->lock); spin_lock_irq(&dev->power.lock); + dev->pm_domain = &genpd->domain; - dev->power.subsys_data->domain_data = &gpd_data->base; - gpd_data->base.dev = dev; - list_add_tail(&gpd_data->base.list_node, &genpd->dev_list); - gpd_data->need_restore = genpd->status == GPD_STATE_POWER_OFF; + if (dev->power.subsys_data->domain_data) { + gpd_data = to_gpd_data(dev->power.subsys_data->domain_data); + } else { + gpd_data = gpd_data_new; + dev->power.subsys_data->domain_data = &gpd_data->base; + } + gpd_data->refcount++; if (td) gpd_data->td = *td; + spin_unlock_irq(&dev->power.lock); + + mutex_lock(&gpd_data->lock); + gpd_data->base.dev = dev; + list_add_tail(&gpd_data->base.list_node, &genpd->dev_list); + gpd_data->need_restore = genpd->status == GPD_STATE_POWER_OFF; gpd_data->td.constraint_changed = true; gpd_data->td.effective_constraint_ns = -1; - spin_unlock_irq(&dev->power.lock); mutex_unlock(&gpd_data->lock); - genpd_release_lock(genpd); - - return 0; - out: genpd_release_lock(genpd); - dev_pm_qos_remove_notifier(dev, &gpd_data->nb); - kfree(gpd_data); + if (gpd_data != gpd_data_new) + __pm_genpd_free_dev_data(dev, gpd_data_new); + return ret; } @@ -1379,6 +1403,7 @@ int pm_genpd_remove_device(struct generic_pm_domain *genpd, { struct generic_pm_domain_data *gpd_data; struct pm_domain_data *pdd; + bool remove = false; int ret = 0; dev_dbg(dev, "%s()\n", __func__); @@ -1399,22 +1424,28 @@ int pm_genpd_remove_device(struct generic_pm_domain *genpd, genpd->max_off_time_changed = true; spin_lock_irq(&dev->power.lock); + dev->pm_domain = NULL; pdd = dev->power.subsys_data->domain_data; list_del_init(&pdd->list_node); - dev->power.subsys_data->domain_data = NULL; + gpd_data = to_gpd_data(pdd); + if (--gpd_data->refcount == 0) { + dev->power.subsys_data->domain_data = NULL; + remove = true; + } + spin_unlock_irq(&dev->power.lock); - gpd_data = to_gpd_data(pdd); mutex_lock(&gpd_data->lock); pdd->dev = NULL; mutex_unlock(&gpd_data->lock); genpd_release_lock(genpd); - dev_pm_qos_remove_notifier(dev, &gpd_data->nb); - kfree(gpd_data); dev_pm_put_subsys_data(dev); + if (remove) + __pm_genpd_free_dev_data(dev, gpd_data); + return 0; out: diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h index 2febe31d267..a7d6172922d 100644 --- a/include/linux/pm_domain.h +++ b/include/linux/pm_domain.h @@ -112,6 +112,7 @@ struct generic_pm_domain_data { struct gpd_timing_data td; struct notifier_block nb; struct mutex lock; + unsigned int refcount; bool need_restore; bool always_on; }; -- cgit v1.2.3-70-g09d2