From: Jean Pihet <[email protected]> Implement the per-device PM QoS constraints by creating a device PM QoS API, which calls the PM QoS constraints management core code.
The per-device latency constraints data strctures are stored in the device dev_pm_info struct. The device PM code calls the init and destroy of the per-device constraints data struct in order to support the dynamic insertion and removal of the devices in the system. To minimize the data usage by the per-device constraints, the data struct is only allocated at the first call to dev_pm_qos_add_request. The data is later free'd when the device is removed from the system. Signed-off-by: Jean Pihet <[email protected]> --- drivers/base/power/Makefile | 4 +- drivers/base/power/main.c | 3 + drivers/base/power/qos.c | 262 +++++++++++++++++++++++++++++++++++++++++++ include/linux/pm.h | 9 ++ include/linux/pm_qos.h | 39 +++++++ 5 files changed, 315 insertions(+), 2 deletions(-) create mode 100644 drivers/base/power/qos.c diff --git a/drivers/base/power/Makefile b/drivers/base/power/Makefile index 3647e11..1a61f89 100644 --- a/drivers/base/power/Makefile +++ b/drivers/base/power/Makefile @@ -1,8 +1,8 @@ -obj-$(CONFIG_PM) += sysfs.o generic_ops.o +obj-$(CONFIG_PM) += sysfs.o generic_ops.o qos.o obj-$(CONFIG_PM_SLEEP) += main.o wakeup.o obj-$(CONFIG_PM_RUNTIME) += runtime.o obj-$(CONFIG_PM_TRACE_RTC) += trace.o obj-$(CONFIG_PM_OPP) += opp.o obj-$(CONFIG_HAVE_CLK) += clock_ops.o -ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG \ No newline at end of file +ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index 06f09bf..f5c0e0e 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -22,6 +22,7 @@ #include <linux/mutex.h> #include <linux/pm.h> #include <linux/pm_runtime.h> +#include <linux/pm_qos.h> #include <linux/resume-trace.h> #include <linux/interrupt.h> #include <linux/sched.h> @@ -97,6 +98,7 @@ void device_pm_add(struct device *dev) dev_name(dev->parent)); list_add_tail(&dev->power.entry, &dpm_list); mutex_unlock(&dpm_list_mtx); + dev_pm_qos_constraints_init(dev); } /** @@ -107,6 +109,7 @@ void device_pm_remove(struct device *dev) { pr_debug("PM: Removing info for %s:%s\n", dev->bus ? dev->bus->name : "No Bus", dev_name(dev)); + dev_pm_qos_constraints_destroy(dev); complete_all(&dev->power.completion); mutex_lock(&dpm_list_mtx); list_del_init(&dev->power.entry); diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c new file mode 100644 index 0000000..465e419 --- /dev/null +++ b/drivers/base/power/qos.c @@ -0,0 +1,262 @@ +/* + * This module exposes the interface to kernel space for specifying + * per-device PM QoS dependencies. It provides infrastructure for registration + * of: + * + * Dependents on a QoS value : register requests + * Watchers of QoS value : get notified when target QoS value changes + * + * This QoS design is best effort based. Dependents register their QoS needs. + * Watchers register to keep track of the current QoS needs of the system. + * + * Note about the per-device constraint data struct allocation: + * . The per-device constraints data struct ptr is tored into the device + * dev_pm_info. + * . To minimize the data usage by the per-device constraints, the data struct + * is only allocated at the first call to dev_pm_qos_add_request. + * . The data is later free'd when the device is removed from the system. + * . The constraints_state variable from dev_pm_info tracks the data struct + * allocation state: + * DEV_PM_QOS_NO_DEVICE: No device present or device removed, no data + * allocated, + * DEV_PM_QOS_DEVICE_PRESENT: Device present, data not allocated and will be + * allocated at the first call to dev_pm_qos_add_request, + * DEV_PM_QOS_ALLOCATED: Device present, data allocated. The per-device + * PM QoS constraints framework is operational and constraints can be + * added, updated or removed using the dev_pm_qos_* API. + */ + +/*#define DEBUG*/ + +#include <linux/pm_qos.h> +#include <linux/sched.h> +#include <linux/spinlock.h> +#include <linux/slab.h> +#include <linux/time.h> +#include <linux/fs.h> +#include <linux/device.h> +#include <linux/string.h> +#include <linux/platform_device.h> +#include <linux/init.h> +#include <linux/kernel.h> + + +static void dev_pm_qos_constraints_allocate(struct device *dev); + +int dev_pm_qos_request_active(struct dev_pm_qos_request *req) +{ + return req->dev != 0; +} +EXPORT_SYMBOL_GPL(dev_pm_qos_request_active); + +/** + * dev_pm_qos_add_request - inserts new qos request into the list + * @req: pointer to a preallocated handle + * @dev: target device for the constraint + * @value: defines the qos request + * + * This function inserts a new entry in the device constraints list of + * requested qos performance characteristics. It recomputes the aggregate + * QoS expectations of parameters and initializes the dev_pm_qos_request + * handle. Caller needs to save this handle for later use in updates and + * removal. + */ +void dev_pm_qos_add_request(struct dev_pm_qos_request *req, struct device *dev, + s32 value) +{ + if (!req) /*guard against callers passing in null */ + return; + + if (dev_pm_qos_request_active(req)) { + WARN(1, KERN_ERR "dev_pm_qos_add_request() called for already " + "added request\n"); + return; + } + req->dev = dev; + + /* Allocate the constraints struct on the first call to add_request */ + if (req->dev->power.constraints_state == DEV_PM_QOS_DEVICE_PRESENT) + dev_pm_qos_constraints_allocate(dev); + + /* Silently return if the device has been removed */ + if (req->dev->power.constraints_state != DEV_PM_QOS_ALLOCATED) + return; + + pm_qos_update_target(dev->power.constraints, + &req->node, PM_QOS_ADD_REQ, value); +} +EXPORT_SYMBOL_GPL(dev_pm_qos_add_request); + +/** + * dev_pm_qos_update_request - modifies an existing qos request + * @req : handle to list element holding a dev_pm_qos request to use + * @value: defines the qos request + * + * Updates an existing dev PM qos request along with updating the + * target value. + * + * Attempts are made to make this code callable on hot code paths. + */ +void dev_pm_qos_update_request(struct dev_pm_qos_request *req, + s32 new_value) +{ + if (!req) /*guard against callers passing in null */ + return; + + if (!dev_pm_qos_request_active(req)) { + WARN(1, KERN_ERR "dev_pm_qos_update_request() called for " + "unknown object\n"); + return; + } + + /* Silently return if the device has been removed */ + if (req->dev->power.constraints_state != DEV_PM_QOS_ALLOCATED) + return; + + if (new_value != req->node.prio) + pm_qos_update_target( + req->dev->power.constraints, + &req->node, PM_QOS_UPDATE_REQ, new_value); +} +EXPORT_SYMBOL_GPL(dev_pm_qos_update_request); + +/** + * dev_pm_qos_remove_request - modifies an existing qos request + * @req: handle to request list element + * + * Will remove pm qos request from the list of constraints and + * recompute the current target value. Call this on slow code paths. + */ +void dev_pm_qos_remove_request(struct dev_pm_qos_request *req) +{ + if (!req) /*guard against callers passing in null */ + return; + + if (!dev_pm_qos_request_active(req)) { + WARN(1, KERN_ERR "dev_pm_qos_remove_request() called for " + "unknown object\n"); + return; + } + + /* Silently return if the device has been removed */ + if (req->dev->power.constraints_state != DEV_PM_QOS_ALLOCATED) + return; + + pm_qos_update_target(req->dev->power.constraints, + &req->node, PM_QOS_REMOVE_REQ, + PM_QOS_DEFAULT_VALUE); + memset(req, 0, sizeof(*req)); +} +EXPORT_SYMBOL_GPL(dev_pm_qos_remove_request); + +/** + * dev_pm_qos_add_notifier - sets notification entry for changes to target value + * of per-device PM QoS constraints + * + * @dev: target device for the constraint + * @notifier: notifier block managed by caller. + * + * Will register the notifier into a notification chain that gets called + * upon changes to the target value for the device. + */ +int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier) +{ + int retval = 0; + + /* Silently return if the device has been removed */ + if (dev->power.constraints_state != DEV_PM_QOS_ALLOCATED) + return retval; + + retval = blocking_notifier_chain_register( + dev->power.constraints->notifiers, + notifier); + + return retval; +} +EXPORT_SYMBOL_GPL(dev_pm_qos_add_notifier); + +/** + * dev_pm_qos_remove_notifier - deletes notification for changes to target value + * of per-device PM QoS constraints + * + * @dev: target device for the constraint + * @notifier: notifier block to be removed. + * + * Will remove the notifier from the notification chain that gets called + * upon changes to the target value. + */ +int dev_pm_qos_remove_notifier(struct device *dev, + struct notifier_block *notifier) +{ + int retval = 0; + + /* Silently return if the device has been removed */ + if (dev->power.constraints_state != DEV_PM_QOS_ALLOCATED) + return retval; + + retval = blocking_notifier_chain_unregister( + dev->power.constraints->notifiers, + notifier); + + return retval; +} +EXPORT_SYMBOL_GPL(dev_pm_qos_remove_notifier); + +/* Called at the first call to add_request, for constraint data allocation */ +static void dev_pm_qos_constraints_allocate(struct device *dev) +{ + struct pm_qos_constraints *c; + struct blocking_notifier_head *n; + + c = kzalloc(sizeof(*c), GFP_KERNEL); + if (!c) + return; + + n = kzalloc(sizeof(*n), GFP_KERNEL); + if (!n) { + kfree(c); + return; + } + BLOCKING_INIT_NOTIFIER_HEAD(n); + + dev->power.constraints = c; + plist_head_init(&dev->power.constraints->list, &dev->power.lock); + dev->power.constraints->target_value = PM_QOS_DEV_LAT_DEFAULT_VALUE; + dev->power.constraints->default_value = PM_QOS_DEV_LAT_DEFAULT_VALUE; + dev->power.constraints->type = PM_QOS_MIN; + dev->power.constraints->notifiers = n; + dev->power.constraints_state = DEV_PM_QOS_ALLOCATED; +} + +/* Called from the device PM subsystem at device insertion */ +void dev_pm_qos_constraints_init(struct device *dev) +{ + dev->power.constraints_state = DEV_PM_QOS_DEVICE_PRESENT; +} + +/* Called from the device PM subsystem at device removal */ +void dev_pm_qos_constraints_destroy(struct device *dev) +{ + struct dev_pm_qos_request *req, *tmp; + enum dev_pm_qos_state constraints_state = dev->power.constraints_state; + + dev->power.constraints_state = DEV_PM_QOS_NO_DEVICE; + if (constraints_state == DEV_PM_QOS_ALLOCATED) { + /* Flush the constraints list for the device */ + plist_for_each_entry_safe(req, tmp, + &dev->power.constraints->list, + node) + /* + * Update constraints list and call the per-device + * callbacks if needed + */ + pm_qos_update_target(req->dev->power.constraints, + &req->node, PM_QOS_REMOVE_REQ, + PM_QOS_DEFAULT_VALUE); + + kfree(dev->power.constraints->notifiers); + kfree(dev->power.constraints); + dev->power.constraints = NULL; + } +} + diff --git a/include/linux/pm.h b/include/linux/pm.h index 411e4f4..aa6dc53 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -421,6 +421,13 @@ enum rpm_request { struct wakeup_source; +/* Per-device PM QoS constraints data struct state */ +enum dev_pm_qos_state { + DEV_PM_QOS_NO_DEVICE, /* No device present */ + DEV_PM_QOS_DEVICE_PRESENT, /* Device present, data not allocated */ + DEV_PM_QOS_ALLOCATED, /* Device present, data allocated */ +}; + struct dev_pm_info { pm_message_t power_state; unsigned int can_wakeup:1; @@ -463,6 +470,8 @@ struct dev_pm_info { unsigned long accounting_timestamp; void *subsys_data; /* Owned by the subsystem. */ #endif + struct pm_qos_constraints *constraints; + enum dev_pm_qos_state constraints_state; }; extern void update_pm_runtime_accounting(struct device *dev); diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h index 84aa150..178eaa1 100644 --- a/include/linux/pm_qos.h +++ b/include/linux/pm_qos.h @@ -19,12 +19,18 @@ #define PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC) #define PM_QOS_NETWORK_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC) #define PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE 0 +#define PM_QOS_DEV_LAT_DEFAULT_VALUE 0 struct pm_qos_request { struct plist_node node; int pm_qos_class; }; +struct dev_pm_qos_request { + struct plist_node node; + struct device *dev; +}; + enum pm_qos_type { PM_QOS_UNITIALIZED, PM_QOS_MAX, /* return the largest value */ @@ -64,6 +70,18 @@ int pm_qos_request(int pm_qos_class); int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier); int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier); int pm_qos_request_active(struct pm_qos_request *req); + +int dev_pm_qos_request_active(struct dev_pm_qos_request *req); +void dev_pm_qos_add_request(struct dev_pm_qos_request *req, struct device *dev, + s32 value); +void dev_pm_qos_update_request(struct dev_pm_qos_request *req, s32 new_value); +void dev_pm_qos_remove_request(struct dev_pm_qos_request *req); +int dev_pm_qos_add_notifier(struct device *dev, + struct notifier_block *notifier); +int dev_pm_qos_remove_notifier(struct device *dev, + struct notifier_block *notifier); +void dev_pm_qos_constraints_init(struct device *dev); +void dev_pm_qos_constraints_destroy(struct device *dev); #else static inline int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node, @@ -89,6 +107,27 @@ static inline int pm_qos_remove_notifier(int pm_qos_class, { return 0; } static inline int pm_qos_request_active(struct pm_qos_request *req) { return 0; } + +static inline int dev_pm_qos_request_active(struct dev_pm_qos_request *req) + { return 0; } +static inline void dev_pm_qos_add_request(struct dev_pm_qos_request *req, + struct device *dev, s32 value) + { return; } +static inline void dev_pm_qos_update_request(struct dev_pm_qos_request *req, + s32 new_value) + { return; } +static inline void dev_pm_qos_remove_request(struct dev_pm_qos_request *req) + { return; } +static inline int dev_pm_qos_add_notifier(struct device *dev, + struct notifier_block *notifier) + { return 0; } +static inline int dev_pm_qos_remove_notifier(struct device *dev, + struct notifier_block *notifier) + { return 0; } +static inline void dev_pm_qos_constraints_init(struct device *dev) + { return; } +static inline void dev_pm_qos_constraints_destroy(struct device *dev) + { return; } #endif #endif -- 1.7.2.5 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
