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673 lines
17 KiB
673 lines
17 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Power Management Quality of Service (PM QoS) support base. |
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* |
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* Copyright (C) 2020 Intel Corporation |
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* |
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* Authors: |
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* Mark Gross <[email protected]> |
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* Rafael J. Wysocki <[email protected]> |
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* |
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* Provided here is an interface for specifying PM QoS dependencies. It allows |
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* entities depending on QoS constraints to register their requests which are |
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* aggregated as appropriate to produce effective constraints (target values) |
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* that can be monitored by entities needing to respect them, either by polling |
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* or through a built-in notification mechanism. |
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* |
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* In addition to the basic functionality, more specific interfaces for managing |
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* global CPU latency QoS requests and frequency QoS requests are provided. |
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*/ |
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/*#define DEBUG*/ |
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#include <linux/pm_qos.h> |
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#include <linux/sched.h> |
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#include <linux/spinlock.h> |
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#include <linux/slab.h> |
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#include <linux/time.h> |
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#include <linux/fs.h> |
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#include <linux/device.h> |
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#include <linux/miscdevice.h> |
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#include <linux/string.h> |
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#include <linux/platform_device.h> |
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#include <linux/init.h> |
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#include <linux/kernel.h> |
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#include <linux/debugfs.h> |
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#include <linux/seq_file.h> |
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#include <linux/uaccess.h> |
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#include <linux/export.h> |
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#include <trace/events/power.h> |
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/* |
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* locking rule: all changes to constraints or notifiers lists |
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* or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock |
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* held, taken with _irqsave. One lock to rule them all |
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*/ |
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static DEFINE_SPINLOCK(pm_qos_lock); |
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/** |
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* pm_qos_read_value - Return the current effective constraint value. |
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* @c: List of PM QoS constraint requests. |
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*/ |
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s32 pm_qos_read_value(struct pm_qos_constraints *c) |
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{ |
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return READ_ONCE(c->target_value); |
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} |
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static int pm_qos_get_value(struct pm_qos_constraints *c) |
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{ |
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if (plist_head_empty(&c->list)) |
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return c->no_constraint_value; |
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switch (c->type) { |
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case PM_QOS_MIN: |
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return plist_first(&c->list)->prio; |
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case PM_QOS_MAX: |
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return plist_last(&c->list)->prio; |
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default: |
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WARN(1, "Unknown PM QoS type in %s\n", __func__); |
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return PM_QOS_DEFAULT_VALUE; |
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} |
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} |
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static void pm_qos_set_value(struct pm_qos_constraints *c, s32 value) |
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{ |
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WRITE_ONCE(c->target_value, value); |
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} |
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/** |
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* pm_qos_update_target - Update a list of PM QoS constraint requests. |
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* @c: List of PM QoS requests. |
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* @node: Target list entry. |
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* @action: Action to carry out (add, update or remove). |
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* @value: New request value for the target list entry. |
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* |
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* Update the given list of PM QoS constraint requests, @c, by carrying an |
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* @action involving the @node list entry and @value on it. |
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* |
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* The recognized values of @action are PM_QOS_ADD_REQ (store @value in @node |
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* and add it to the list), PM_QOS_UPDATE_REQ (remove @node from the list, store |
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* @value in it and add it to the list again), and PM_QOS_REMOVE_REQ (remove |
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* @node from the list, ignore @value). |
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* |
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* Return: 1 if the aggregate constraint value has changed, 0 otherwise. |
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*/ |
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int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node, |
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enum pm_qos_req_action action, int value) |
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{ |
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int prev_value, curr_value, new_value; |
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unsigned long flags; |
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spin_lock_irqsave(&pm_qos_lock, flags); |
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prev_value = pm_qos_get_value(c); |
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if (value == PM_QOS_DEFAULT_VALUE) |
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new_value = c->default_value; |
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else |
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new_value = value; |
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switch (action) { |
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case PM_QOS_REMOVE_REQ: |
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plist_del(node, &c->list); |
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break; |
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case PM_QOS_UPDATE_REQ: |
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/* |
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* To change the list, atomically remove, reinit with new value |
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* and add, then see if the aggregate has changed. |
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*/ |
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plist_del(node, &c->list); |
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fallthrough; |
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case PM_QOS_ADD_REQ: |
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plist_node_init(node, new_value); |
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plist_add(node, &c->list); |
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break; |
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default: |
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/* no action */ |
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; |
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} |
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curr_value = pm_qos_get_value(c); |
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pm_qos_set_value(c, curr_value); |
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spin_unlock_irqrestore(&pm_qos_lock, flags); |
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trace_pm_qos_update_target(action, prev_value, curr_value); |
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if (prev_value == curr_value) |
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return 0; |
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if (c->notifiers) |
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blocking_notifier_call_chain(c->notifiers, curr_value, NULL); |
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return 1; |
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} |
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/** |
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* pm_qos_flags_remove_req - Remove device PM QoS flags request. |
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* @pqf: Device PM QoS flags set to remove the request from. |
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* @req: Request to remove from the set. |
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*/ |
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static void pm_qos_flags_remove_req(struct pm_qos_flags *pqf, |
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struct pm_qos_flags_request *req) |
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{ |
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s32 val = 0; |
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list_del(&req->node); |
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list_for_each_entry(req, &pqf->list, node) |
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val |= req->flags; |
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pqf->effective_flags = val; |
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} |
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/** |
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* pm_qos_update_flags - Update a set of PM QoS flags. |
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* @pqf: Set of PM QoS flags to update. |
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* @req: Request to add to the set, to modify, or to remove from the set. |
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* @action: Action to take on the set. |
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* @val: Value of the request to add or modify. |
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* |
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* Return: 1 if the aggregate constraint value has changed, 0 otherwise. |
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*/ |
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bool pm_qos_update_flags(struct pm_qos_flags *pqf, |
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struct pm_qos_flags_request *req, |
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enum pm_qos_req_action action, s32 val) |
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{ |
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unsigned long irqflags; |
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s32 prev_value, curr_value; |
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spin_lock_irqsave(&pm_qos_lock, irqflags); |
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prev_value = list_empty(&pqf->list) ? 0 : pqf->effective_flags; |
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switch (action) { |
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case PM_QOS_REMOVE_REQ: |
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pm_qos_flags_remove_req(pqf, req); |
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break; |
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case PM_QOS_UPDATE_REQ: |
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pm_qos_flags_remove_req(pqf, req); |
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fallthrough; |
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case PM_QOS_ADD_REQ: |
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req->flags = val; |
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INIT_LIST_HEAD(&req->node); |
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list_add_tail(&req->node, &pqf->list); |
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pqf->effective_flags |= val; |
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break; |
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default: |
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/* no action */ |
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; |
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} |
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curr_value = list_empty(&pqf->list) ? 0 : pqf->effective_flags; |
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spin_unlock_irqrestore(&pm_qos_lock, irqflags); |
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trace_pm_qos_update_flags(action, prev_value, curr_value); |
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return prev_value != curr_value; |
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} |
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#ifdef CONFIG_CPU_IDLE |
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/* Definitions related to the CPU latency QoS. */ |
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static struct pm_qos_constraints cpu_latency_constraints = { |
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.list = PLIST_HEAD_INIT(cpu_latency_constraints.list), |
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.target_value = PM_QOS_CPU_LATENCY_DEFAULT_VALUE, |
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.default_value = PM_QOS_CPU_LATENCY_DEFAULT_VALUE, |
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.no_constraint_value = PM_QOS_CPU_LATENCY_DEFAULT_VALUE, |
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.type = PM_QOS_MIN, |
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}; |
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/** |
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* cpu_latency_qos_limit - Return current system-wide CPU latency QoS limit. |
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*/ |
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s32 cpu_latency_qos_limit(void) |
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{ |
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return pm_qos_read_value(&cpu_latency_constraints); |
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} |
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/** |
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* cpu_latency_qos_request_active - Check the given PM QoS request. |
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* @req: PM QoS request to check. |
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* |
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* Return: 'true' if @req has been added to the CPU latency QoS list, 'false' |
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* otherwise. |
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*/ |
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bool cpu_latency_qos_request_active(struct pm_qos_request *req) |
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{ |
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return req->qos == &cpu_latency_constraints; |
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} |
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EXPORT_SYMBOL_GPL(cpu_latency_qos_request_active); |
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static void cpu_latency_qos_apply(struct pm_qos_request *req, |
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enum pm_qos_req_action action, s32 value) |
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{ |
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int ret = pm_qos_update_target(req->qos, &req->node, action, value); |
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if (ret > 0) |
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wake_up_all_idle_cpus(); |
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} |
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/** |
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* cpu_latency_qos_add_request - Add new CPU latency QoS request. |
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* @req: Pointer to a preallocated handle. |
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* @value: Requested constraint value. |
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* |
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* Use @value to initialize the request handle pointed to by @req, insert it as |
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* a new entry to the CPU latency QoS list and recompute the effective QoS |
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* constraint for that list. |
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* |
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* Callers need to save the handle for later use in updates and removal of the |
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* QoS request represented by it. |
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*/ |
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void cpu_latency_qos_add_request(struct pm_qos_request *req, s32 value) |
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{ |
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if (!req) |
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return; |
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if (cpu_latency_qos_request_active(req)) { |
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WARN(1, KERN_ERR "%s called for already added request\n", __func__); |
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return; |
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} |
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trace_pm_qos_add_request(value); |
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req->qos = &cpu_latency_constraints; |
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cpu_latency_qos_apply(req, PM_QOS_ADD_REQ, value); |
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} |
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EXPORT_SYMBOL_GPL(cpu_latency_qos_add_request); |
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/** |
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* cpu_latency_qos_update_request - Modify existing CPU latency QoS request. |
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* @req : QoS request to update. |
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* @new_value: New requested constraint value. |
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* |
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* Use @new_value to update the QoS request represented by @req in the CPU |
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* latency QoS list along with updating the effective constraint value for that |
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* list. |
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*/ |
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void cpu_latency_qos_update_request(struct pm_qos_request *req, s32 new_value) |
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{ |
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if (!req) |
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return; |
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if (!cpu_latency_qos_request_active(req)) { |
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WARN(1, KERN_ERR "%s called for unknown object\n", __func__); |
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return; |
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} |
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trace_pm_qos_update_request(new_value); |
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if (new_value == req->node.prio) |
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return; |
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cpu_latency_qos_apply(req, PM_QOS_UPDATE_REQ, new_value); |
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} |
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EXPORT_SYMBOL_GPL(cpu_latency_qos_update_request); |
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/** |
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* cpu_latency_qos_remove_request - Remove existing CPU latency QoS request. |
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* @req: QoS request to remove. |
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* |
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* Remove the CPU latency QoS request represented by @req from the CPU latency |
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* QoS list along with updating the effective constraint value for that list. |
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*/ |
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void cpu_latency_qos_remove_request(struct pm_qos_request *req) |
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{ |
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if (!req) |
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return; |
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if (!cpu_latency_qos_request_active(req)) { |
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WARN(1, KERN_ERR "%s called for unknown object\n", __func__); |
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return; |
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} |
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trace_pm_qos_remove_request(PM_QOS_DEFAULT_VALUE); |
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cpu_latency_qos_apply(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE); |
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memset(req, 0, sizeof(*req)); |
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} |
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EXPORT_SYMBOL_GPL(cpu_latency_qos_remove_request); |
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/* User space interface to the CPU latency QoS via misc device. */ |
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static int cpu_latency_qos_open(struct inode *inode, struct file *filp) |
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{ |
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struct pm_qos_request *req; |
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req = kzalloc(sizeof(*req), GFP_KERNEL); |
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if (!req) |
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return -ENOMEM; |
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cpu_latency_qos_add_request(req, PM_QOS_DEFAULT_VALUE); |
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filp->private_data = req; |
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return 0; |
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} |
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static int cpu_latency_qos_release(struct inode *inode, struct file *filp) |
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{ |
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struct pm_qos_request *req = filp->private_data; |
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filp->private_data = NULL; |
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cpu_latency_qos_remove_request(req); |
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kfree(req); |
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return 0; |
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} |
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static ssize_t cpu_latency_qos_read(struct file *filp, char __user *buf, |
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size_t count, loff_t *f_pos) |
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{ |
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struct pm_qos_request *req = filp->private_data; |
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unsigned long flags; |
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s32 value; |
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if (!req || !cpu_latency_qos_request_active(req)) |
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return -EINVAL; |
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spin_lock_irqsave(&pm_qos_lock, flags); |
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value = pm_qos_get_value(&cpu_latency_constraints); |
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spin_unlock_irqrestore(&pm_qos_lock, flags); |
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return simple_read_from_buffer(buf, count, f_pos, &value, sizeof(s32)); |
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} |
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static ssize_t cpu_latency_qos_write(struct file *filp, const char __user *buf, |
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size_t count, loff_t *f_pos) |
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{ |
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s32 value; |
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if (count == sizeof(s32)) { |
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if (copy_from_user(&value, buf, sizeof(s32))) |
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return -EFAULT; |
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} else { |
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int ret; |
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ret = kstrtos32_from_user(buf, count, 16, &value); |
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if (ret) |
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return ret; |
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} |
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cpu_latency_qos_update_request(filp->private_data, value); |
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return count; |
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} |
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static const struct file_operations cpu_latency_qos_fops = { |
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.write = cpu_latency_qos_write, |
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.read = cpu_latency_qos_read, |
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.open = cpu_latency_qos_open, |
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.release = cpu_latency_qos_release, |
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.llseek = noop_llseek, |
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}; |
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static struct miscdevice cpu_latency_qos_miscdev = { |
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.minor = MISC_DYNAMIC_MINOR, |
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.name = "cpu_dma_latency", |
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.fops = &cpu_latency_qos_fops, |
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}; |
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static int __init cpu_latency_qos_init(void) |
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{ |
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int ret; |
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ret = misc_register(&cpu_latency_qos_miscdev); |
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if (ret < 0) |
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pr_err("%s: %s setup failed\n", __func__, |
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cpu_latency_qos_miscdev.name); |
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return ret; |
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} |
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late_initcall(cpu_latency_qos_init); |
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#endif /* CONFIG_CPU_IDLE */ |
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/* Definitions related to the frequency QoS below. */ |
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/** |
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* freq_constraints_init - Initialize frequency QoS constraints. |
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* @qos: Frequency QoS constraints to initialize. |
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*/ |
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void freq_constraints_init(struct freq_constraints *qos) |
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{ |
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struct pm_qos_constraints *c; |
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c = &qos->min_freq; |
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plist_head_init(&c->list); |
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c->target_value = FREQ_QOS_MIN_DEFAULT_VALUE; |
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c->default_value = FREQ_QOS_MIN_DEFAULT_VALUE; |
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c->no_constraint_value = FREQ_QOS_MIN_DEFAULT_VALUE; |
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c->type = PM_QOS_MAX; |
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c->notifiers = &qos->min_freq_notifiers; |
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BLOCKING_INIT_NOTIFIER_HEAD(c->notifiers); |
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c = &qos->max_freq; |
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plist_head_init(&c->list); |
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c->target_value = FREQ_QOS_MAX_DEFAULT_VALUE; |
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c->default_value = FREQ_QOS_MAX_DEFAULT_VALUE; |
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c->no_constraint_value = FREQ_QOS_MAX_DEFAULT_VALUE; |
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c->type = PM_QOS_MIN; |
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c->notifiers = &qos->max_freq_notifiers; |
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BLOCKING_INIT_NOTIFIER_HEAD(c->notifiers); |
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} |
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/** |
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* freq_qos_read_value - Get frequency QoS constraint for a given list. |
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* @qos: Constraints to evaluate. |
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* @type: QoS request type. |
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*/ |
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s32 freq_qos_read_value(struct freq_constraints *qos, |
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enum freq_qos_req_type type) |
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{ |
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s32 ret; |
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switch (type) { |
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case FREQ_QOS_MIN: |
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ret = IS_ERR_OR_NULL(qos) ? |
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FREQ_QOS_MIN_DEFAULT_VALUE : |
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pm_qos_read_value(&qos->min_freq); |
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break; |
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case FREQ_QOS_MAX: |
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ret = IS_ERR_OR_NULL(qos) ? |
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FREQ_QOS_MAX_DEFAULT_VALUE : |
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pm_qos_read_value(&qos->max_freq); |
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break; |
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default: |
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WARN_ON(1); |
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ret = 0; |
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} |
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return ret; |
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} |
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/** |
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* freq_qos_apply - Add/modify/remove frequency QoS request. |
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* @req: Constraint request to apply. |
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* @action: Action to perform (add/update/remove). |
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* @value: Value to assign to the QoS request. |
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* |
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* This is only meant to be called from inside pm_qos, not drivers. |
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*/ |
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int freq_qos_apply(struct freq_qos_request *req, |
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enum pm_qos_req_action action, s32 value) |
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{ |
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int ret; |
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switch(req->type) { |
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case FREQ_QOS_MIN: |
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ret = pm_qos_update_target(&req->qos->min_freq, &req->pnode, |
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action, value); |
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break; |
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case FREQ_QOS_MAX: |
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ret = pm_qos_update_target(&req->qos->max_freq, &req->pnode, |
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action, value); |
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break; |
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default: |
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ret = -EINVAL; |
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} |
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return ret; |
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} |
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/** |
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* freq_qos_add_request - Insert new frequency QoS request into a given list. |
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* @qos: Constraints to update. |
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* @req: Preallocated request object. |
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* @type: Request type. |
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* @value: Request value. |
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* |
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* Insert a new entry into the @qos list of requests, recompute the effective |
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* QoS constraint value for that list and initialize the @req object. The |
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* caller needs to save that object for later use in updates and removal. |
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* |
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* Return 1 if the effective constraint value has changed, 0 if the effective |
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* constraint value has not changed, or a negative error code on failures. |
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*/ |
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int freq_qos_add_request(struct freq_constraints *qos, |
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struct freq_qos_request *req, |
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enum freq_qos_req_type type, s32 value) |
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{ |
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int ret; |
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if (IS_ERR_OR_NULL(qos) || !req) |
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return -EINVAL; |
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if (WARN(freq_qos_request_active(req), |
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"%s() called for active request\n", __func__)) |
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return -EINVAL; |
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req->qos = qos; |
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req->type = type; |
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ret = freq_qos_apply(req, PM_QOS_ADD_REQ, value); |
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if (ret < 0) { |
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req->qos = NULL; |
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req->type = 0; |
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} |
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return ret; |
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} |
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EXPORT_SYMBOL_GPL(freq_qos_add_request); |
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|
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/** |
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* freq_qos_update_request - Modify existing frequency QoS request. |
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* @req: Request to modify. |
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* @new_value: New request value. |
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* |
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* Update an existing frequency QoS request along with the effective constraint |
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* value for the list of requests it belongs to. |
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* |
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* Return 1 if the effective constraint value has changed, 0 if the effective |
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* constraint value has not changed, or a negative error code on failures. |
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*/ |
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int freq_qos_update_request(struct freq_qos_request *req, s32 new_value) |
|
{ |
|
if (!req) |
|
return -EINVAL; |
|
|
|
if (WARN(!freq_qos_request_active(req), |
|
"%s() called for unknown object\n", __func__)) |
|
return -EINVAL; |
|
|
|
if (req->pnode.prio == new_value) |
|
return 0; |
|
|
|
return freq_qos_apply(req, PM_QOS_UPDATE_REQ, new_value); |
|
} |
|
EXPORT_SYMBOL_GPL(freq_qos_update_request); |
|
|
|
/** |
|
* 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) |
|
{ |
|
int ret; |
|
|
|
if (!req) |
|
return -EINVAL; |
|
|
|
if (WARN(!freq_qos_request_active(req), |
|
"%s() called for unknown object\n", __func__)) |
|
return -EINVAL; |
|
|
|
ret = freq_qos_apply(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE); |
|
req->qos = NULL; |
|
req->type = 0; |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL_GPL(freq_qos_remove_request); |
|
|
|
/** |
|
* 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) |
|
{ |
|
int ret; |
|
|
|
if (IS_ERR_OR_NULL(qos) || !notifier) |
|
return -EINVAL; |
|
|
|
switch (type) { |
|
case FREQ_QOS_MIN: |
|
ret = blocking_notifier_chain_register(qos->min_freq.notifiers, |
|
notifier); |
|
break; |
|
case FREQ_QOS_MAX: |
|
ret = blocking_notifier_chain_register(qos->max_freq.notifiers, |
|
notifier); |
|
break; |
|
default: |
|
WARN_ON(1); |
|
ret = -EINVAL; |
|
} |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL_GPL(freq_qos_add_notifier); |
|
|
|
/** |
|
* 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) |
|
{ |
|
int ret; |
|
|
|
if (IS_ERR_OR_NULL(qos) || !notifier) |
|
return -EINVAL; |
|
|
|
switch (type) { |
|
case FREQ_QOS_MIN: |
|
ret = blocking_notifier_chain_unregister(qos->min_freq.notifiers, |
|
notifier); |
|
break; |
|
case FREQ_QOS_MAX: |
|
ret = blocking_notifier_chain_unregister(qos->max_freq.notifiers, |
|
notifier); |
|
break; |
|
default: |
|
WARN_ON(1); |
|
ret = -EINVAL; |
|
} |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL_GPL(freq_qos_remove_notifier);
|
|
|