diff options
Diffstat (limited to 'drivers/base/power/qos.c')
| -rw-r--r-- | drivers/base/power/qos.c | 886 |
1 files changed, 886 insertions, 0 deletions
diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c new file mode 100644 index 000000000..3382542b3 --- /dev/null +++ b/drivers/base/power/qos.c @@ -0,0 +1,886 @@ +/* + * Devices PM QoS constraints management + * + * Copyright (C) 2011 Texas Instruments, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * + * 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. + * Watchers can register a per-device notification callback using the + * dev_pm_qos_*_notifier API. The notification chain data is stored in the + * per-device constraint data struct. + * + * 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. + * . A global mutex protects the constraints users from the data being + * allocated and free'd. + */ + +#include <linux/pm_qos.h> +#include <linux/spinlock.h> +#include <linux/slab.h> +#include <linux/device.h> +#include <linux/mutex.h> +#include <linux/export.h> +#include <linux/pm_runtime.h> +#include <linux/err.h> +#include <trace/events/power.h> + +#include "power.h" + +static DEFINE_MUTEX(dev_pm_qos_mtx); +static DEFINE_MUTEX(dev_pm_qos_sysfs_mtx); + +/** + * __dev_pm_qos_flags - Check PM QoS flags for a given device. + * @dev: Device to check the PM QoS flags for. + * @mask: Flags to check against. + * + * This routine must be called with dev->power.lock held. + */ +enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev, s32 mask) +{ + struct dev_pm_qos *qos = dev->power.qos; + struct pm_qos_flags *pqf; + s32 val; + + lockdep_assert_held(&dev->power.lock); + + if (IS_ERR_OR_NULL(qos)) + return PM_QOS_FLAGS_UNDEFINED; + + pqf = &qos->flags; + if (list_empty(&pqf->list)) + return PM_QOS_FLAGS_UNDEFINED; + + val = pqf->effective_flags & mask; + if (val) + return (val == mask) ? PM_QOS_FLAGS_ALL : PM_QOS_FLAGS_SOME; + + return PM_QOS_FLAGS_NONE; +} + +/** + * dev_pm_qos_flags - Check PM QoS flags for a given device (locked). + * @dev: Device to check the PM QoS flags for. + * @mask: Flags to check against. + */ +enum pm_qos_flags_status dev_pm_qos_flags(struct device *dev, s32 mask) +{ + unsigned long irqflags; + enum pm_qos_flags_status ret; + + spin_lock_irqsave(&dev->power.lock, irqflags); + ret = __dev_pm_qos_flags(dev, mask); + spin_unlock_irqrestore(&dev->power.lock, irqflags); + + return ret; +} +EXPORT_SYMBOL_GPL(dev_pm_qos_flags); + +/** + * __dev_pm_qos_read_value - Get PM QoS constraint for a given device. + * @dev: Device to get the PM QoS constraint value for. + * + * This routine must be called with dev->power.lock held. + */ +s32 __dev_pm_qos_read_value(struct device *dev) +{ + lockdep_assert_held(&dev->power.lock); + + return dev_pm_qos_raw_read_value(dev); +} + +/** + * dev_pm_qos_read_value - Get PM QoS constraint for a given device (locked). + * @dev: Device to get the PM QoS constraint value for. + */ +s32 dev_pm_qos_read_value(struct device *dev) +{ + unsigned long flags; + s32 ret; + + spin_lock_irqsave(&dev->power.lock, flags); + ret = __dev_pm_qos_read_value(dev); + spin_unlock_irqrestore(&dev->power.lock, flags); + + return ret; +} + +/** + * apply_constraint - Add/modify/remove device PM QoS request. + * @req: Constraint request to apply + * @action: Action to perform (add/update/remove). + * @value: Value to assign to the QoS request. + * + * Internal function to update the constraints list using the PM QoS core + * code and if needed call the per-device callbacks. + */ +static int apply_constraint(struct dev_pm_qos_request *req, + enum pm_qos_req_action action, s32 value) +{ + struct dev_pm_qos *qos = req->dev->power.qos; + int ret; + + switch(req->type) { + case DEV_PM_QOS_RESUME_LATENCY: + if (WARN_ON(action != PM_QOS_REMOVE_REQ && value < 0)) + value = 0; + + ret = pm_qos_update_target(&qos->resume_latency, + &req->data.pnode, action, value); + break; + case DEV_PM_QOS_LATENCY_TOLERANCE: + ret = pm_qos_update_target(&qos->latency_tolerance, + &req->data.pnode, action, value); + if (ret) { + value = pm_qos_read_value(&qos->latency_tolerance); + req->dev->power.set_latency_tolerance(req->dev, value); + } + break; + case DEV_PM_QOS_FLAGS: + ret = pm_qos_update_flags(&qos->flags, &req->data.flr, + action, value); + break; + default: + ret = -EINVAL; + } + + return ret; +} + +/* + * dev_pm_qos_constraints_allocate + * @dev: device to allocate data for + * + * Called at the first call to add_request, for constraint data allocation + * Must be called with the dev_pm_qos_mtx mutex held + */ +static int dev_pm_qos_constraints_allocate(struct device *dev) +{ + struct dev_pm_qos *qos; + struct pm_qos_constraints *c; + struct blocking_notifier_head *n; + + qos = kzalloc(sizeof(*qos), GFP_KERNEL); + if (!qos) + return -ENOMEM; + + n = kzalloc(sizeof(*n), GFP_KERNEL); + if (!n) { + kfree(qos); + return -ENOMEM; + } + BLOCKING_INIT_NOTIFIER_HEAD(n); + + c = &qos->resume_latency; + plist_head_init(&c->list); + c->target_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE; + c->default_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE; + c->no_constraint_value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT; + c->type = PM_QOS_MIN; + c->notifiers = n; + + c = &qos->latency_tolerance; + plist_head_init(&c->list); + c->target_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE; + c->default_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE; + c->no_constraint_value = PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT; + c->type = PM_QOS_MIN; + + INIT_LIST_HEAD(&qos->flags.list); + + spin_lock_irq(&dev->power.lock); + dev->power.qos = qos; + spin_unlock_irq(&dev->power.lock); + + return 0; +} + +static void __dev_pm_qos_hide_latency_limit(struct device *dev); +static void __dev_pm_qos_hide_flags(struct device *dev); + +/** + * dev_pm_qos_constraints_destroy + * @dev: target device + * + * Called from the device PM subsystem on device removal under device_pm_lock(). + */ +void dev_pm_qos_constraints_destroy(struct device *dev) +{ + struct dev_pm_qos *qos; + struct dev_pm_qos_request *req, *tmp; + struct pm_qos_constraints *c; + struct pm_qos_flags *f; + + mutex_lock(&dev_pm_qos_sysfs_mtx); + + /* + * If the device's PM QoS resume latency limit or PM QoS flags have been + * exposed to user space, they have to be hidden at this point. + */ + pm_qos_sysfs_remove_resume_latency(dev); + pm_qos_sysfs_remove_flags(dev); + + mutex_lock(&dev_pm_qos_mtx); + + __dev_pm_qos_hide_latency_limit(dev); + __dev_pm_qos_hide_flags(dev); + + qos = dev->power.qos; + if (!qos) + goto out; + + /* Flush the constraints lists for the device. */ + c = &qos->resume_latency; + plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) { + /* + * Update constraints list and call the notification + * callbacks if needed + */ + apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE); + memset(req, 0, sizeof(*req)); + } + c = &qos->latency_tolerance; + plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) { + apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE); + memset(req, 0, sizeof(*req)); + } + f = &qos->flags; + list_for_each_entry_safe(req, tmp, &f->list, data.flr.node) { + apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE); + memset(req, 0, sizeof(*req)); + } + + spin_lock_irq(&dev->power.lock); + dev->power.qos = ERR_PTR(-ENODEV); + spin_unlock_irq(&dev->power.lock); + + kfree(qos->resume_latency.notifiers); + kfree(qos); + + out: + mutex_unlock(&dev_pm_qos_mtx); + + mutex_unlock(&dev_pm_qos_sysfs_mtx); +} + +static bool dev_pm_qos_invalid_req_type(struct device *dev, + enum dev_pm_qos_req_type type) +{ + return type == DEV_PM_QOS_LATENCY_TOLERANCE && + !dev->power.set_latency_tolerance; +} + +static int __dev_pm_qos_add_request(struct device *dev, + struct dev_pm_qos_request *req, + enum dev_pm_qos_req_type type, s32 value) +{ + int ret = 0; + + if (!dev || !req || dev_pm_qos_invalid_req_type(dev, type)) + return -EINVAL; + + if (WARN(dev_pm_qos_request_active(req), + "%s() called for already added request\n", __func__)) + return -EINVAL; + + if (IS_ERR(dev->power.qos)) + ret = -ENODEV; + else if (!dev->power.qos) + ret = dev_pm_qos_constraints_allocate(dev); + + trace_dev_pm_qos_add_request(dev_name(dev), type, value); + if (!ret) { + req->dev = dev; + req->type = type; + ret = apply_constraint(req, PM_QOS_ADD_REQ, value); + } + return ret; +} + +/** + * dev_pm_qos_add_request - inserts new qos request into the list + * @dev: target device for the constraint + * @req: pointer to a preallocated handle + * @type: type of the request + * @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. + * + * Returns 1 if the aggregated constraint value has changed, + * 0 if the aggregated constraint value has not changed, + * -EINVAL in case of wrong parameters, -ENOMEM if there's not enough memory + * to allocate for data structures, -ENODEV if the device has just been removed + * from the system. + * + * Callers should ensure that the target device is not RPM_SUSPENDED before + * using this function for requests of type DEV_PM_QOS_FLAGS. + */ +int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req, + enum dev_pm_qos_req_type type, s32 value) +{ + int ret; + + mutex_lock(&dev_pm_qos_mtx); + ret = __dev_pm_qos_add_request(dev, req, type, value); + mutex_unlock(&dev_pm_qos_mtx); + return ret; +} +EXPORT_SYMBOL_GPL(dev_pm_qos_add_request); + +/** + * __dev_pm_qos_update_request - Modify an existing device PM QoS request. + * @req : PM QoS request to modify. + * @new_value: New value to request. + */ +static int __dev_pm_qos_update_request(struct dev_pm_qos_request *req, + s32 new_value) +{ + s32 curr_value; + int ret = 0; + + if (!req) /*guard against callers passing in null */ + return -EINVAL; + + if (WARN(!dev_pm_qos_request_active(req), + "%s() called for unknown object\n", __func__)) + return -EINVAL; + + if (IS_ERR_OR_NULL(req->dev->power.qos)) + return -ENODEV; + + switch(req->type) { + case DEV_PM_QOS_RESUME_LATENCY: + case DEV_PM_QOS_LATENCY_TOLERANCE: + curr_value = req->data.pnode.prio; + break; + case DEV_PM_QOS_FLAGS: + curr_value = req->data.flr.flags; + break; + default: + return -EINVAL; + } + + trace_dev_pm_qos_update_request(dev_name(req->dev), req->type, + new_value); + if (curr_value != new_value) + ret = apply_constraint(req, PM_QOS_UPDATE_REQ, new_value); + + return ret; +} + +/** + * dev_pm_qos_update_request - modifies an existing qos request + * @req : handle to list element holding a dev_pm_qos request to use + * @new_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. + * + * Returns 1 if the aggregated constraint value has changed, + * 0 if the aggregated constraint value has not changed, + * -EINVAL in case of wrong parameters, -ENODEV if the device has been + * removed from the system + * + * Callers should ensure that the target device is not RPM_SUSPENDED before + * using this function for requests of type DEV_PM_QOS_FLAGS. + */ +int dev_pm_qos_update_request(struct dev_pm_qos_request *req, s32 new_value) +{ + int ret; + + mutex_lock(&dev_pm_qos_mtx); + ret = __dev_pm_qos_update_request(req, new_value); + mutex_unlock(&dev_pm_qos_mtx); + return ret; +} +EXPORT_SYMBOL_GPL(dev_pm_qos_update_request); + +static int __dev_pm_qos_remove_request(struct dev_pm_qos_request *req) +{ + int ret; + + if (!req) /*guard against callers passing in null */ + return -EINVAL; + + if (WARN(!dev_pm_qos_request_active(req), + "%s() called for unknown object\n", __func__)) + return -EINVAL; + + if (IS_ERR_OR_NULL(req->dev->power.qos)) + return -ENODEV; + + trace_dev_pm_qos_remove_request(dev_name(req->dev), req->type, + PM_QOS_DEFAULT_VALUE); + ret = apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE); + memset(req, 0, sizeof(*req)); + return ret; +} + +/** + * 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. + * + * Returns 1 if the aggregated constraint value has changed, + * 0 if the aggregated constraint value has not changed, + * -EINVAL in case of wrong parameters, -ENODEV if the device has been + * removed from the system + * + * Callers should ensure that the target device is not RPM_SUSPENDED before + * using this function for requests of type DEV_PM_QOS_FLAGS. + */ +int dev_pm_qos_remove_request(struct dev_pm_qos_request *req) +{ + int ret; + + mutex_lock(&dev_pm_qos_mtx); + ret = __dev_pm_qos_remove_request(req); + mutex_unlock(&dev_pm_qos_mtx); + return ret; +} +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. + * + * If the device's constraints object doesn't exist when this routine is called, + * it will be created (or error code will be returned if that fails). + */ +int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier) +{ + int ret = 0; + + mutex_lock(&dev_pm_qos_mtx); + + if (IS_ERR(dev->power.qos)) + ret = -ENODEV; + else if (!dev->power.qos) + ret = dev_pm_qos_constraints_allocate(dev); + + if (!ret) + ret = blocking_notifier_chain_register(dev->power.qos->resume_latency.notifiers, + notifier); + + mutex_unlock(&dev_pm_qos_mtx); + return ret; +} +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; + + mutex_lock(&dev_pm_qos_mtx); + + /* Silently return if the constraints object is not present. */ + if (!IS_ERR_OR_NULL(dev->power.qos)) + retval = blocking_notifier_chain_unregister(dev->power.qos->resume_latency.notifiers, + notifier); + + mutex_unlock(&dev_pm_qos_mtx); + return retval; +} +EXPORT_SYMBOL_GPL(dev_pm_qos_remove_notifier); + +/** + * dev_pm_qos_add_ancestor_request - Add PM QoS request for device's ancestor. + * @dev: Device whose ancestor to add the request for. + * @req: Pointer to the preallocated handle. + * @type: Type of the request. + * @value: Constraint latency value. + */ +int dev_pm_qos_add_ancestor_request(struct device *dev, + struct dev_pm_qos_request *req, + enum dev_pm_qos_req_type type, s32 value) +{ + struct device *ancestor = dev->parent; + int ret = -ENODEV; + + switch (type) { + case DEV_PM_QOS_RESUME_LATENCY: + while (ancestor && !ancestor->power.ignore_children) + ancestor = ancestor->parent; + + break; + case DEV_PM_QOS_LATENCY_TOLERANCE: + while (ancestor && !ancestor->power.set_latency_tolerance) + ancestor = ancestor->parent; + + break; + default: + ancestor = NULL; + } + if (ancestor) + ret = dev_pm_qos_add_request(ancestor, req, type, value); + + if (ret < 0) + req->dev = NULL; + + return ret; +} +EXPORT_SYMBOL_GPL(dev_pm_qos_add_ancestor_request); + +static void __dev_pm_qos_drop_user_request(struct device *dev, + enum dev_pm_qos_req_type type) +{ + struct dev_pm_qos_request *req = NULL; + + switch(type) { + case DEV_PM_QOS_RESUME_LATENCY: + req = dev->power.qos->resume_latency_req; + dev->power.qos->resume_latency_req = NULL; + break; + case DEV_PM_QOS_LATENCY_TOLERANCE: + req = dev->power.qos->latency_tolerance_req; + dev->power.qos->latency_tolerance_req = NULL; + break; + case DEV_PM_QOS_FLAGS: + req = dev->power.qos->flags_req; + dev->power.qos->flags_req = NULL; + break; + } + __dev_pm_qos_remove_request(req); + kfree(req); +} + +static void dev_pm_qos_drop_user_request(struct device *dev, + enum dev_pm_qos_req_type type) +{ + mutex_lock(&dev_pm_qos_mtx); + __dev_pm_qos_drop_user_request(dev, type); + mutex_unlock(&dev_pm_qos_mtx); +} + +/** + * dev_pm_qos_expose_latency_limit - Expose PM QoS latency limit to user space. + * @dev: Device whose PM QoS latency limit is to be exposed to user space. + * @value: Initial value of the latency limit. + */ +int dev_pm_qos_expose_latency_limit(struct device *dev, s32 value) +{ + struct dev_pm_qos_request *req; + int ret; + + if (!device_is_registered(dev) || value < 0) + return -EINVAL; + + req = kzalloc(sizeof(*req), GFP_KERNEL); + if (!req) + return -ENOMEM; + + ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_RESUME_LATENCY, value); + if (ret < 0) { + kfree(req); + return ret; + } + + mutex_lock(&dev_pm_qos_sysfs_mtx); + + mutex_lock(&dev_pm_qos_mtx); + + if (IS_ERR_OR_NULL(dev->power.qos)) + ret = -ENODEV; + else if (dev->power.qos->resume_latency_req) + ret = -EEXIST; + + if (ret < 0) { + __dev_pm_qos_remove_request(req); + kfree(req); + mutex_unlock(&dev_pm_qos_mtx); + goto out; + } + dev->power.qos->resume_latency_req = req; + + mutex_unlock(&dev_pm_qos_mtx); + + ret = pm_qos_sysfs_add_resume_latency(dev); + if (ret) + dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_RESUME_LATENCY); + + out: + mutex_unlock(&dev_pm_qos_sysfs_mtx); + return ret; +} +EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_limit); + +static void __dev_pm_qos_hide_latency_limit(struct device *dev) +{ + if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->resume_latency_req) + __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_RESUME_LATENCY); +} + +/** + * dev_pm_qos_hide_latency_limit - Hide PM QoS latency limit from user space. + * @dev: Device whose PM QoS latency limit is to be hidden from user space. + */ +void dev_pm_qos_hide_latency_limit(struct device *dev) +{ + mutex_lock(&dev_pm_qos_sysfs_mtx); + + pm_qos_sysfs_remove_resume_latency(dev); + + mutex_lock(&dev_pm_qos_mtx); + __dev_pm_qos_hide_latency_limit(dev); + mutex_unlock(&dev_pm_qos_mtx); + + mutex_unlock(&dev_pm_qos_sysfs_mtx); +} +EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_limit); + +/** + * dev_pm_qos_expose_flags - Expose PM QoS flags of a device to user space. + * @dev: Device whose PM QoS flags are to be exposed to user space. + * @val: Initial values of the flags. + */ +int dev_pm_qos_expose_flags(struct device *dev, s32 val) +{ + struct dev_pm_qos_request *req; + int ret; + + if (!device_is_registered(dev)) + return -EINVAL; + + req = kzalloc(sizeof(*req), GFP_KERNEL); + if (!req) + return -ENOMEM; + + ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_FLAGS, val); + if (ret < 0) { + kfree(req); + return ret; + } + + pm_runtime_get_sync(dev); + mutex_lock(&dev_pm_qos_sysfs_mtx); + + mutex_lock(&dev_pm_qos_mtx); + + if (IS_ERR_OR_NULL(dev->power.qos)) + ret = -ENODEV; + else if (dev->power.qos->flags_req) + ret = -EEXIST; + + if (ret < 0) { + __dev_pm_qos_remove_request(req); + kfree(req); + mutex_unlock(&dev_pm_qos_mtx); + goto out; + } + dev->power.qos->flags_req = req; + + mutex_unlock(&dev_pm_qos_mtx); + + ret = pm_qos_sysfs_add_flags(dev); + if (ret) + dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_FLAGS); + + out: + mutex_unlock(&dev_pm_qos_sysfs_mtx); + pm_runtime_put(dev); + return ret; +} +EXPORT_SYMBOL_GPL(dev_pm_qos_expose_flags); + +static void __dev_pm_qos_hide_flags(struct device *dev) +{ + if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->flags_req) + __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_FLAGS); +} + +/** + * dev_pm_qos_hide_flags - Hide PM QoS flags of a device from user space. + * @dev: Device whose PM QoS flags are to be hidden from user space. + */ +void dev_pm_qos_hide_flags(struct device *dev) +{ + pm_runtime_get_sync(dev); + mutex_lock(&dev_pm_qos_sysfs_mtx); + + pm_qos_sysfs_remove_flags(dev); + + mutex_lock(&dev_pm_qos_mtx); + __dev_pm_qos_hide_flags(dev); + mutex_unlock(&dev_pm_qos_mtx); + + mutex_unlock(&dev_pm_qos_sysfs_mtx); + pm_runtime_put(dev); +} +EXPORT_SYMBOL_GPL(dev_pm_qos_hide_flags); + +/** + * dev_pm_qos_update_flags - Update PM QoS flags request owned by user space. + * @dev: Device to update the PM QoS flags request for. + * @mask: Flags to set/clear. + * @set: Whether to set or clear the flags (true means set). + */ +int dev_pm_qos_update_flags(struct device *dev, s32 mask, bool set) +{ + s32 value; + int ret; + + pm_runtime_get_sync(dev); + mutex_lock(&dev_pm_qos_mtx); + + if (IS_ERR_OR_NULL(dev->power.qos) || !dev->power.qos->flags_req) { + ret = -EINVAL; + goto out; + } + + value = dev_pm_qos_requested_flags(dev); + if (set) + value |= mask; + else + value &= ~mask; + + ret = __dev_pm_qos_update_request(dev->power.qos->flags_req, value); + + out: + mutex_unlock(&dev_pm_qos_mtx); + pm_runtime_put(dev); + return ret; +} + +/** + * dev_pm_qos_get_user_latency_tolerance - Get user space latency tolerance. + * @dev: Device to obtain the user space latency tolerance for. + */ +s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev) +{ + s32 ret; + + mutex_lock(&dev_pm_qos_mtx); + ret = IS_ERR_OR_NULL(dev->power.qos) + || !dev->power.qos->latency_tolerance_req ? + PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT : + dev->power.qos->latency_tolerance_req->data.pnode.prio; + mutex_unlock(&dev_pm_qos_mtx); + return ret; +} + +/** + * dev_pm_qos_update_user_latency_tolerance - Update user space latency tolerance. + * @dev: Device to update the user space latency tolerance for. + * @val: New user space latency tolerance for @dev (negative values disable). + */ +int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val) +{ + int ret; + + mutex_lock(&dev_pm_qos_mtx); + + if (IS_ERR_OR_NULL(dev->power.qos) + || !dev->power.qos->latency_tolerance_req) { + struct dev_pm_qos_request *req; + + if (val < 0) { + if (val == PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT) + ret = 0; + else + ret = -EINVAL; + goto out; + } + req = kzalloc(sizeof(*req), GFP_KERNEL); + if (!req) { + ret = -ENOMEM; + goto out; + } + ret = __dev_pm_qos_add_request(dev, req, DEV_PM_QOS_LATENCY_TOLERANCE, val); + if (ret < 0) { + kfree(req); + goto out; + } + dev->power.qos->latency_tolerance_req = req; + } else { + if (val < 0) { + __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY_TOLERANCE); + ret = 0; + } else { + ret = __dev_pm_qos_update_request(dev->power.qos->latency_tolerance_req, val); + } + } + + out: + mutex_unlock(&dev_pm_qos_mtx); + return ret; +} +EXPORT_SYMBOL_GPL(dev_pm_qos_update_user_latency_tolerance); + +/** + * dev_pm_qos_expose_latency_tolerance - Expose latency tolerance to userspace + * @dev: Device whose latency tolerance to expose + */ +int dev_pm_qos_expose_latency_tolerance(struct device *dev) +{ + int ret; + + if (!dev->power.set_latency_tolerance) + return -EINVAL; + + mutex_lock(&dev_pm_qos_sysfs_mtx); + ret = pm_qos_sysfs_add_latency_tolerance(dev); + mutex_unlock(&dev_pm_qos_sysfs_mtx); + + return ret; +} +EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_tolerance); + +/** + * dev_pm_qos_hide_latency_tolerance - Hide latency tolerance from userspace + * @dev: Device whose latency tolerance to hide + */ +void dev_pm_qos_hide_latency_tolerance(struct device *dev) +{ + mutex_lock(&dev_pm_qos_sysfs_mtx); + pm_qos_sysfs_remove_latency_tolerance(dev); + mutex_unlock(&dev_pm_qos_sysfs_mtx); + + /* Remove the request from user space now */ + pm_runtime_get_sync(dev); + dev_pm_qos_update_user_latency_tolerance(dev, + PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT); + pm_runtime_put(dev); +} +EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_tolerance); |