// SPDX-License-Identifier: GPL-2.0-only /* * Power Management Quality of Service (PM QoS) support base. * * Copyright (C) 2020 Intel Corporation * * Authors: * Mark Gross <[email protected]> * Rafael J. Wysocki <[email protected]> * * Provided here is an interface for specifying PM QoS dependencies. It allows * entities depending on QoS constraints to register their requests which are * aggregated as appropriate to produce effective constraints (target values) * that can be monitored by entities needing to respect them, either by polling * or through a built-in notification mechanism. * * In addition to the basic functionality, more specific interfaces for managing * global CPU latency QoS requests and frequency QoS requests are provided. */ /*#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/miscdevice.h> #include <linux/string.h> #include <linux/platform_device.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/debugfs.h> #include <linux/seq_file.h> #include <linux/uaccess.h> #include <linux/export.h> #include <trace/events/power.h> /* * locking rule: all changes to constraints or notifiers lists * or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock * held, taken with _irqsave. One lock to rule them all */ static DEFINE_SPINLOCK(pm_qos_lock); /** * pm_qos_read_value - Return the current effective constraint value. * @c: List of PM QoS constraint requests. */ s32 pm_qos_read_value(struct pm_qos_constraints *c) { … } static int pm_qos_get_value(struct pm_qos_constraints *c) { … } static void pm_qos_set_value(struct pm_qos_constraints *c, s32 value) { … } /** * pm_qos_update_target - Update a list of PM QoS constraint requests. * @c: List of PM QoS requests. * @node: Target list entry. * @action: Action to carry out (add, update or remove). * @value: New request value for the target list entry. * * Update the given list of PM QoS constraint requests, @c, by carrying an * @action involving the @node list entry and @value on it. * * The recognized values of @action are PM_QOS_ADD_REQ (store @value in @node * and add it to the list), PM_QOS_UPDATE_REQ (remove @node from the list, store * @value in it and add it to the list again), and PM_QOS_REMOVE_REQ (remove * @node from the list, ignore @value). * * Return: 1 if the aggregate constraint value has changed, 0 otherwise. */ int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node, enum pm_qos_req_action action, int value) { … } /** * pm_qos_flags_remove_req - Remove device PM QoS flags request. * @pqf: Device PM QoS flags set to remove the request from. * @req: Request to remove from the set. */ static void pm_qos_flags_remove_req(struct pm_qos_flags *pqf, struct pm_qos_flags_request *req) { … } /** * pm_qos_update_flags - Update a set of PM QoS flags. * @pqf: Set of PM QoS flags to update. * @req: Request to add to the set, to modify, or to remove from the set. * @action: Action to take on the set. * @val: Value of the request to add or modify. * * Return: 1 if the aggregate constraint value has changed, 0 otherwise. */ bool pm_qos_update_flags(struct pm_qos_flags *pqf, struct pm_qos_flags_request *req, enum pm_qos_req_action action, s32 val) { … } #ifdef CONFIG_CPU_IDLE /* Definitions related to the CPU latency QoS. */ static struct pm_qos_constraints cpu_latency_constraints = …; static inline bool cpu_latency_qos_value_invalid(s32 value) { … } /** * cpu_latency_qos_limit - Return current system-wide CPU latency QoS limit. */ s32 cpu_latency_qos_limit(void) { … } /** * cpu_latency_qos_request_active - Check the given PM QoS request. * @req: PM QoS request to check. * * Return: 'true' if @req has been added to the CPU latency QoS list, 'false' * otherwise. */ bool cpu_latency_qos_request_active(struct pm_qos_request *req) { … } EXPORT_SYMBOL_GPL(…); static void cpu_latency_qos_apply(struct pm_qos_request *req, enum pm_qos_req_action action, s32 value) { … } /** * cpu_latency_qos_add_request - Add new CPU latency QoS request. * @req: Pointer to a preallocated handle. * @value: Requested constraint value. * * Use @value to initialize the request handle pointed to by @req, insert it as * a new entry to the CPU latency QoS list and recompute the effective QoS * constraint for that list. * * Callers need to save the handle for later use in updates and removal of the * QoS request represented by it. */ void cpu_latency_qos_add_request(struct pm_qos_request *req, s32 value) { … } EXPORT_SYMBOL_GPL(…); /** * cpu_latency_qos_update_request - Modify existing CPU latency QoS request. * @req : QoS request to update. * @new_value: New requested constraint value. * * Use @new_value to update the QoS request represented by @req in the CPU * latency QoS list along with updating the effective constraint value for that * list. */ void cpu_latency_qos_update_request(struct pm_qos_request *req, s32 new_value) { … } EXPORT_SYMBOL_GPL(…); /** * cpu_latency_qos_remove_request - Remove existing CPU latency QoS request. * @req: QoS request to remove. * * Remove the CPU latency QoS request represented by @req from the CPU latency * QoS list along with updating the effective constraint value for that list. */ void cpu_latency_qos_remove_request(struct pm_qos_request *req) { … } EXPORT_SYMBOL_GPL(…); /* User space interface to the CPU latency QoS via misc device. */ static int cpu_latency_qos_open(struct inode *inode, struct file *filp) { … } static int cpu_latency_qos_release(struct inode *inode, struct file *filp) { … } static ssize_t cpu_latency_qos_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos) { … } static ssize_t cpu_latency_qos_write(struct file *filp, const char __user *buf, size_t count, loff_t *f_pos) { … } static const struct file_operations cpu_latency_qos_fops = …; static struct miscdevice cpu_latency_qos_miscdev = …; static int __init cpu_latency_qos_init(void) { … } late_initcall(cpu_latency_qos_init); #endif /* CONFIG_CPU_IDLE */ /* Definitions related to the frequency QoS below. */ static inline bool freq_qos_value_invalid(s32 value) { … } /** * freq_constraints_init - Initialize frequency QoS constraints. * @qos: Frequency QoS constraints to initialize. */ void freq_constraints_init(struct freq_constraints *qos) { … } /** * freq_qos_read_value - Get frequency QoS constraint for a given list. * @qos: Constraints to evaluate. * @type: QoS request type. */ s32 freq_qos_read_value(struct freq_constraints *qos, enum freq_qos_req_type type) { … } /** * freq_qos_apply - Add/modify/remove frequency QoS request. * @req: Constraint request to apply. * @action: Action to perform (add/update/remove). * @value: Value to assign to the QoS request. * * This is only meant to be called from inside pm_qos, not drivers. */ int freq_qos_apply(struct freq_qos_request *req, enum pm_qos_req_action action, s32 value) { … } /** * freq_qos_add_request - Insert new frequency QoS request into a given list. * @qos: Constraints to update. * @req: Preallocated request object. * @type: Request type. * @value: Request value. * * Insert a new entry into the @qos list of requests, recompute the effective * QoS constraint value for that list and initialize the @req object. The * caller needs to save that object for later use in updates and removal. * * Return 1 if the effective constraint value has changed, 0 if the effective * constraint value has not changed, or a negative error code on failures. */ int freq_qos_add_request(struct freq_constraints *qos, struct freq_qos_request *req, enum freq_qos_req_type type, s32 value) { … } EXPORT_SYMBOL_GPL(…); /** * freq_qos_update_request - Modify existing frequency QoS request. * @req: Request to modify. * @new_value: New request value. * * Update an existing frequency QoS request along with the effective constraint * value for the list of requests it belongs to. * * Return 1 if the effective constraint value has changed, 0 if the effective * constraint value has not changed, or a negative error code on failures. */ int freq_qos_update_request(struct freq_qos_request *req, s32 new_value) { … } EXPORT_SYMBOL_GPL(…); /** * freq_qos_remove_request - Remove frequency QoS request from its list. * @req: Request to remove. * * Remove the given frequency QoS request from the list of constraints it * belongs to and recompute the effective constraint value for that list. * * Return 1 if the effective constraint value has changed, 0 if the effective * constraint value has not changed, or a negative error code on failures. */ int freq_qos_remove_request(struct freq_qos_request *req) { … } EXPORT_SYMBOL_GPL(…); /** * freq_qos_add_notifier - Add frequency QoS change notifier. * @qos: List of requests to add the notifier to. * @type: Request type. * @notifier: Notifier block to add. */ int freq_qos_add_notifier(struct freq_constraints *qos, enum freq_qos_req_type type, struct notifier_block *notifier) { … } EXPORT_SYMBOL_GPL(…); /** * freq_qos_remove_notifier - Remove frequency QoS change notifier. * @qos: List of requests to remove the notifier from. * @type: Request type. * @notifier: Notifier block to remove. */ int freq_qos_remove_notifier(struct freq_constraints *qos, enum freq_qos_req_type type, struct notifier_block *notifier) { … } EXPORT_SYMBOL_GPL(…);
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