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![Gustavo A. R. Silva](/assets/img/avatar_default.png)
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
673 lines
17 KiB
C
673 lines
17 KiB
C
// 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 <mgross@linux.intel.com>
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* Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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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)
|
|
{
|
|
int ret;
|
|
|
|
switch(req->type) {
|
|
case FREQ_QOS_MIN:
|
|
ret = pm_qos_update_target(&req->qos->min_freq, &req->pnode,
|
|
action, value);
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|
break;
|
|
case FREQ_QOS_MAX:
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|
ret = pm_qos_update_target(&req->qos->max_freq, &req->pnode,
|
|
action, value);
|
|
break;
|
|
default:
|
|
ret = -EINVAL;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
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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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|
*
|
|
* 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)
|
|
{
|
|
int ret;
|
|
|
|
if (IS_ERR_OR_NULL(qos) || !req)
|
|
return -EINVAL;
|
|
|
|
if (WARN(freq_qos_request_active(req),
|
|
"%s() called for active request\n", __func__))
|
|
return -EINVAL;
|
|
|
|
req->qos = qos;
|
|
req->type = type;
|
|
ret = freq_qos_apply(req, PM_QOS_ADD_REQ, value);
|
|
if (ret < 0) {
|
|
req->qos = NULL;
|
|
req->type = 0;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(freq_qos_add_request);
|
|
|
|
/**
|
|
* 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)
|
|
{
|
|
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);
|