PM QoS: Implement per-device PM QoS constraints
Implement the per-device PM QoS constraints by creating a device PM QoS API, which calls the PM QoS constraints management core code. The per-device latency constraints data strctures are stored in the device dev_pm_info struct. The device PM code calls the init and destroy of the per-device constraints data struct in order to support the dynamic insertion and removal of the devices in the system. To minimize the data usage by the per-device constraints, the data struct is only allocated at the first call to dev_pm_qos_add_request. The data is later free'd when the device is removed from the system. A global mutex protects the constraints users from the data being allocated and free'd. Signed-off-by: Jean Pihet <j-pihet@ti.com> Reviewed-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This commit is contained in:
Jean Pihet
Rafael J. Wysocki
parent
abe98ec2d8
commit
91ff4cb803
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@ -1,4 +1,4 @@
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obj-$(CONFIG_PM) += sysfs.o generic_ops.o common.o
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obj-$(CONFIG_PM) += sysfs.o generic_ops.o common.o qos.o
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obj-$(CONFIG_PM_SLEEP) += main.o wakeup.o
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obj-$(CONFIG_PM_RUNTIME) += runtime.o
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obj-$(CONFIG_PM_TRACE_RTC) += trace.o
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@ -6,4 +6,4 @@ obj-$(CONFIG_PM_OPP) += opp.o
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obj-$(CONFIG_PM_GENERIC_DOMAINS) += domain.o
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obj-$(CONFIG_HAVE_CLK) += clock_ops.o
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ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
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ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
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@ -22,6 +22,7 @@
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#include <linux/mutex.h>
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#include <linux/pm.h>
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#include <linux/pm_runtime.h>
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#include <linux/pm_qos.h>
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#include <linux/resume-trace.h>
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#include <linux/interrupt.h>
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#include <linux/sched.h>
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@ -97,6 +98,7 @@ void device_pm_add(struct device *dev)
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dev_name(dev->parent));
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list_add_tail(&dev->power.entry, &dpm_list);
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mutex_unlock(&dpm_list_mtx);
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dev_pm_qos_constraints_init(dev);
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}
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/**
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@ -107,6 +109,7 @@ void device_pm_remove(struct device *dev)
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{
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pr_debug("PM: Removing info for %s:%s\n",
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dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
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dev_pm_qos_constraints_destroy(dev);
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complete_all(&dev->power.completion);
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mutex_lock(&dpm_list_mtx);
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list_del_init(&dev->power.entry);
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@ -0,0 +1,338 @@
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/*
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* Devices PM QoS constraints management
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*
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* Copyright (C) 2011 Texas Instruments, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*
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* This module exposes the interface to kernel space for specifying
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* per-device PM QoS dependencies. It provides infrastructure for registration
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* of:
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*
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* Dependents on a QoS value : register requests
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* Watchers of QoS value : get notified when target QoS value changes
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*
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* This QoS design is best effort based. Dependents register their QoS needs.
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* Watchers register to keep track of the current QoS needs of the system.
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*
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* Note about the per-device constraint data struct allocation:
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* . The per-device constraints data struct ptr is tored into the device
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* dev_pm_info.
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* . To minimize the data usage by the per-device constraints, the data struct
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* is only allocated at the first call to dev_pm_qos_add_request.
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* . The data is later free'd when the device is removed from the system.
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* . The constraints_state variable from dev_pm_info tracks the data struct
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* allocation state:
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* DEV_PM_QOS_NO_DEVICE: No device present or device removed, no data
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* allocated,
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* DEV_PM_QOS_DEVICE_PRESENT: Device present, data not allocated and will be
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* allocated at the first call to dev_pm_qos_add_request,
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* DEV_PM_QOS_ALLOCATED: Device present, data allocated. The per-device
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* PM QoS constraints framework is operational and constraints can be
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* added, updated or removed using the dev_pm_qos_* API.
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* . A global mutex protects the constraints users from the data being
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* allocated and free'd.
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*/
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#include <linux/pm_qos.h>
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#include <linux/spinlock.h>
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#include <linux/slab.h>
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#include <linux/device.h>
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#include <linux/mutex.h>
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static DEFINE_MUTEX(dev_pm_qos_mtx);
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/*
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* dev_pm_qos_constraints_allocate
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* @dev: device to allocate data for
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*
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* Called at the first call to add_request, for constraint data allocation
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* Must be called with the dev_pm_qos_mtx mutex held
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*/
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static int dev_pm_qos_constraints_allocate(struct device *dev)
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{
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struct pm_qos_constraints *c;
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struct blocking_notifier_head *n;
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c = kzalloc(sizeof(*c), GFP_KERNEL);
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if (!c)
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return -ENOMEM;
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n = kzalloc(sizeof(*n), GFP_KERNEL);
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if (!n) {
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kfree(c);
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return -ENOMEM;
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}
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BLOCKING_INIT_NOTIFIER_HEAD(n);
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dev->power.constraints = c;
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plist_head_init(&dev->power.constraints->list);
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dev->power.constraints->target_value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
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dev->power.constraints->default_value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
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dev->power.constraints->type = PM_QOS_MIN;
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dev->power.constraints->notifiers = n;
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dev->power.constraints_state = DEV_PM_QOS_ALLOCATED;
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return 0;
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}
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/**
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* dev_pm_qos_constraints_init
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* @dev: target device
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*
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* Called from the device PM subsystem at device insertion
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*/
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void dev_pm_qos_constraints_init(struct device *dev)
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{
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mutex_lock(&dev_pm_qos_mtx);
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dev->power.constraints_state = DEV_PM_QOS_DEVICE_PRESENT;
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mutex_unlock(&dev_pm_qos_mtx);
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}
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/**
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* dev_pm_qos_constraints_destroy
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* @dev: target device
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*
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* Called from the device PM subsystem at device removal
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*/
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void dev_pm_qos_constraints_destroy(struct device *dev)
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{
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struct dev_pm_qos_request *req, *tmp;
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mutex_lock(&dev_pm_qos_mtx);
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if (dev->power.constraints_state == DEV_PM_QOS_ALLOCATED) {
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/* Flush the constraints list for the device */
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plist_for_each_entry_safe(req, tmp,
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&dev->power.constraints->list,
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node) {
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/*
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* Update constraints list and call the per-device
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* callbacks if needed
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*/
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pm_qos_update_target(req->dev->power.constraints,
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&req->node, PM_QOS_REMOVE_REQ,
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PM_QOS_DEFAULT_VALUE);
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memset(req, 0, sizeof(*req));
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}
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kfree(dev->power.constraints->notifiers);
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kfree(dev->power.constraints);
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dev->power.constraints = NULL;
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}
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dev->power.constraints_state = DEV_PM_QOS_NO_DEVICE;
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mutex_unlock(&dev_pm_qos_mtx);
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}
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/**
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* dev_pm_qos_add_request - inserts new qos request into the list
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* @dev: target device for the constraint
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* @req: pointer to a preallocated handle
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* @value: defines the qos request
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*
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* This function inserts a new entry in the device constraints list of
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* requested qos performance characteristics. It recomputes the aggregate
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* QoS expectations of parameters and initializes the dev_pm_qos_request
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* handle. Caller needs to save this handle for later use in updates and
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* removal.
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*
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* Returns 1 if the aggregated constraint value has changed,
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* 0 if the aggregated constraint value has not changed,
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* -EINVAL in case of wrong parameters, -ENODEV if the device has been
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* removed from the system
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*/
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int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
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s32 value)
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{
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int ret = 0;
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if (!dev || !req) /*guard against callers passing in null */
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return -EINVAL;
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if (dev_pm_qos_request_active(req)) {
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WARN(1, KERN_ERR "dev_pm_qos_add_request() called for already "
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"added request\n");
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return -EINVAL;
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}
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mutex_lock(&dev_pm_qos_mtx);
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req->dev = dev;
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/* Return if the device has been removed */
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if (req->dev->power.constraints_state == DEV_PM_QOS_NO_DEVICE) {
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ret = -ENODEV;
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goto out;
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}
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/*
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* Allocate the constraints data on the first call to add_request,
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* i.e. only if the data is not already allocated and if the device has
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* not been removed
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*/
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if (dev->power.constraints_state == DEV_PM_QOS_DEVICE_PRESENT)
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ret = dev_pm_qos_constraints_allocate(dev);
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if (!ret)
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ret = pm_qos_update_target(dev->power.constraints, &req->node,
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PM_QOS_ADD_REQ, value);
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out:
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mutex_unlock(&dev_pm_qos_mtx);
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return ret;
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}
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EXPORT_SYMBOL_GPL(dev_pm_qos_add_request);
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/**
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* dev_pm_qos_update_request - modifies an existing qos request
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* @req : handle to list element holding a dev_pm_qos request to use
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* @new_value: defines the qos request
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*
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* Updates an existing dev PM qos request along with updating the
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* target value.
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*
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* Attempts are made to make this code callable on hot code paths.
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*
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* Returns 1 if the aggregated constraint value has changed,
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* 0 if the aggregated constraint value has not changed,
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* -EINVAL in case of wrong parameters, -ENODEV if the device has been
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* removed from the system
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*/
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int dev_pm_qos_update_request(struct dev_pm_qos_request *req,
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s32 new_value)
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{
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int ret = 0;
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if (!req) /*guard against callers passing in null */
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return -EINVAL;
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if (!dev_pm_qos_request_active(req)) {
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WARN(1, KERN_ERR "dev_pm_qos_update_request() called for "
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"unknown object\n");
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return -EINVAL;
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}
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mutex_lock(&dev_pm_qos_mtx);
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if (req->dev->power.constraints_state == DEV_PM_QOS_ALLOCATED) {
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if (new_value != req->node.prio)
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ret = pm_qos_update_target(req->dev->power.constraints,
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&req->node,
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PM_QOS_UPDATE_REQ,
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new_value);
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} else {
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/* Return if the device has been removed */
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ret = -ENODEV;
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}
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mutex_unlock(&dev_pm_qos_mtx);
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return ret;
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}
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EXPORT_SYMBOL_GPL(dev_pm_qos_update_request);
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/**
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* dev_pm_qos_remove_request - modifies an existing qos request
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* @req: handle to request list element
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*
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* Will remove pm qos request from the list of constraints and
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* recompute the current target value. Call this on slow code paths.
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*
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* Returns 1 if the aggregated constraint value has changed,
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* 0 if the aggregated constraint value has not changed,
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* -EINVAL in case of wrong parameters, -ENODEV if the device has been
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* removed from the system
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*/
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int dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
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{
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int ret = 0;
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if (!req) /*guard against callers passing in null */
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return -EINVAL;
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if (!dev_pm_qos_request_active(req)) {
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WARN(1, KERN_ERR "dev_pm_qos_remove_request() called for "
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"unknown object\n");
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return -EINVAL;
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}
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mutex_lock(&dev_pm_qos_mtx);
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if (req->dev->power.constraints_state == DEV_PM_QOS_ALLOCATED) {
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ret = pm_qos_update_target(req->dev->power.constraints,
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&req->node, PM_QOS_REMOVE_REQ,
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PM_QOS_DEFAULT_VALUE);
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memset(req, 0, sizeof(*req));
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} else {
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/* Return if the device has been removed */
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ret = -ENODEV;
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}
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mutex_unlock(&dev_pm_qos_mtx);
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return ret;
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}
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EXPORT_SYMBOL_GPL(dev_pm_qos_remove_request);
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/**
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* dev_pm_qos_add_notifier - sets notification entry for changes to target value
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* of per-device PM QoS constraints
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*
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* @dev: target device for the constraint
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* @notifier: notifier block managed by caller.
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*
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* Will register the notifier into a notification chain that gets called
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* upon changes to the target value for the device.
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*/
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int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier)
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{
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int retval = 0;
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mutex_lock(&dev_pm_qos_mtx);
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/* Silently return if the device has been removed */
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if (dev->power.constraints_state != DEV_PM_QOS_ALLOCATED)
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goto out;
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retval = blocking_notifier_chain_register(
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dev->power.constraints->notifiers,
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notifier);
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out:
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mutex_unlock(&dev_pm_qos_mtx);
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return retval;
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}
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EXPORT_SYMBOL_GPL(dev_pm_qos_add_notifier);
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/**
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* dev_pm_qos_remove_notifier - deletes notification for changes to target value
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* of per-device PM QoS constraints
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*
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* @dev: target device for the constraint
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* @notifier: notifier block to be removed.
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*
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* Will remove the notifier from the notification chain that gets called
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* upon changes to the target value.
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*/
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int dev_pm_qos_remove_notifier(struct device *dev,
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struct notifier_block *notifier)
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{
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int retval = 0;
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mutex_lock(&dev_pm_qos_mtx);
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/* Silently return if the device has been removed */
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if (dev->power.constraints_state != DEV_PM_QOS_ALLOCATED)
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goto out;
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retval = blocking_notifier_chain_unregister(
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dev->power.constraints->notifiers,
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notifier);
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out:
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mutex_unlock(&dev_pm_qos_mtx);
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return retval;
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}
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EXPORT_SYMBOL_GPL(dev_pm_qos_remove_notifier);
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@ -419,6 +419,13 @@ enum rpm_request {
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RPM_REQ_RESUME,
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};
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/* Per-device PM QoS constraints data struct state */
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enum dev_pm_qos_state {
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DEV_PM_QOS_NO_DEVICE, /* No device present */
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DEV_PM_QOS_DEVICE_PRESENT, /* Device present, data not allocated */
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DEV_PM_QOS_ALLOCATED, /* Device present, data allocated */
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};
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struct wakeup_source;
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struct pm_domain_data {
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@ -480,6 +487,8 @@ struct dev_pm_info {
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unsigned long accounting_timestamp;
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#endif
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struct pm_subsys_data *subsys_data; /* Owned by the subsystem. */
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struct pm_qos_constraints *constraints;
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enum dev_pm_qos_state constraints_state;
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};
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extern void update_pm_runtime_accounting(struct device *dev);
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@ -19,12 +19,18 @@
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#define PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC)
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#define PM_QOS_NETWORK_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC)
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#define PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE 0
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#define PM_QOS_DEV_LAT_DEFAULT_VALUE 0
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struct pm_qos_request {
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struct plist_node node;
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int pm_qos_class;
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};
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struct dev_pm_qos_request {
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struct plist_node node;
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struct device *dev;
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};
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enum pm_qos_type {
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PM_QOS_UNITIALIZED,
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PM_QOS_MAX, /* return the largest value */
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@ -51,6 +57,11 @@ enum pm_qos_req_action {
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PM_QOS_REMOVE_REQ /* Remove an existing request */
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};
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static inline int dev_pm_qos_request_active(struct dev_pm_qos_request *req)
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{
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return req->dev != 0;
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}
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#ifdef CONFIG_PM
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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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@ -64,6 +75,17 @@ int pm_qos_request(int pm_qos_class);
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int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier);
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int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier);
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int pm_qos_request_active(struct pm_qos_request *req);
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int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
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s32 value);
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int dev_pm_qos_update_request(struct dev_pm_qos_request *req, s32 new_value);
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int dev_pm_qos_remove_request(struct dev_pm_qos_request *req);
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int dev_pm_qos_add_notifier(struct device *dev,
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||||
struct notifier_block *notifier);
|
||||
int dev_pm_qos_remove_notifier(struct device *dev,
|
||||
struct notifier_block *notifier);
|
||||
void dev_pm_qos_constraints_init(struct device *dev);
|
||||
void dev_pm_qos_constraints_destroy(struct device *dev);
|
||||
#else
|
||||
static inline int pm_qos_update_target(struct pm_qos_constraints *c,
|
||||
struct plist_node *node,
|
||||
|
|
@ -89,6 +111,26 @@ static inline int pm_qos_remove_notifier(int pm_qos_class,
|
|||
{ return 0; }
|
||||
static inline int pm_qos_request_active(struct pm_qos_request *req)
|
||||
{ return 0; }
|
||||
|
||||
static inline int dev_pm_qos_add_request(struct device *dev,
|
||||
struct dev_pm_qos_request *req,
|
||||
s32 value)
|
||||
{ return 0; }
|
||||
static inline int dev_pm_qos_update_request(struct dev_pm_qos_request *req,
|
||||
s32 new_value)
|
||||
{ return 0; }
|
||||
static inline int dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
|
||||
{ return 0; }
|
||||
static inline int dev_pm_qos_add_notifier(struct device *dev,
|
||||
struct notifier_block *notifier)
|
||||
{ return 0; }
|
||||
static inline int dev_pm_qos_remove_notifier(struct device *dev,
|
||||
struct notifier_block *notifier)
|
||||
{ return 0; }
|
||||
static inline void dev_pm_qos_constraints_init(struct device *dev)
|
||||
{ return; }
|
||||
static inline void dev_pm_qos_constraints_destroy(struct device *dev)
|
||||
{ return; }
|
||||
#endif
|
||||
|
||||
#endif
|
||||
|
|
|
|||
Loading…
Reference in New Issue