![Thomas Gleixner](/assets/img/avatar_default.png)
Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
701 lines
19 KiB
C
701 lines
19 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* This module exposes the interface to kernel space for specifying
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* QoS dependencies. It provides infrastructure for registration 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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* There are 3 basic classes of QoS parameter: latency, timeout, throughput
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* each have defined units:
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* latency: usec
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* timeout: usec <-- currently not used.
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* throughput: kbs (kilo byte / sec)
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*
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* There are lists of pm_qos_objects each one wrapping requests, notifiers
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*
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* User mode requests on a QOS parameter register themselves to the
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* subsystem by opening the device node /dev/... and writing there request to
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* the node. As long as the process holds a file handle open to the node the
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* client continues to be accounted for. Upon file release the usermode
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* request is removed and a new qos target is computed. This way when the
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* request that the application has is cleaned up when closes the file
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* pointer or exits the pm_qos_object will get an opportunity to clean up.
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*
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* Mark Gross <mgross@linux.intel.com>
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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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struct pm_qos_object {
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struct pm_qos_constraints *constraints;
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struct miscdevice pm_qos_power_miscdev;
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char *name;
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};
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static DEFINE_SPINLOCK(pm_qos_lock);
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static struct pm_qos_object null_pm_qos;
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static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
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static struct pm_qos_constraints cpu_dma_constraints = {
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.list = PLIST_HEAD_INIT(cpu_dma_constraints.list),
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.target_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
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.default_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
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.no_constraint_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
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.type = PM_QOS_MIN,
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.notifiers = &cpu_dma_lat_notifier,
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};
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static struct pm_qos_object cpu_dma_pm_qos = {
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.constraints = &cpu_dma_constraints,
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.name = "cpu_dma_latency",
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};
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static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
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static struct pm_qos_constraints network_lat_constraints = {
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.list = PLIST_HEAD_INIT(network_lat_constraints.list),
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.target_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
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.default_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
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.no_constraint_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
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.type = PM_QOS_MIN,
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.notifiers = &network_lat_notifier,
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};
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static struct pm_qos_object network_lat_pm_qos = {
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.constraints = &network_lat_constraints,
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.name = "network_latency",
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};
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static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
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static struct pm_qos_constraints network_tput_constraints = {
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.list = PLIST_HEAD_INIT(network_tput_constraints.list),
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.target_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
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.default_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
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.no_constraint_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
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.type = PM_QOS_MAX,
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.notifiers = &network_throughput_notifier,
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};
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static struct pm_qos_object network_throughput_pm_qos = {
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.constraints = &network_tput_constraints,
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.name = "network_throughput",
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};
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static BLOCKING_NOTIFIER_HEAD(memory_bandwidth_notifier);
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static struct pm_qos_constraints memory_bw_constraints = {
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.list = PLIST_HEAD_INIT(memory_bw_constraints.list),
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.target_value = PM_QOS_MEMORY_BANDWIDTH_DEFAULT_VALUE,
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.default_value = PM_QOS_MEMORY_BANDWIDTH_DEFAULT_VALUE,
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.no_constraint_value = PM_QOS_MEMORY_BANDWIDTH_DEFAULT_VALUE,
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.type = PM_QOS_SUM,
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.notifiers = &memory_bandwidth_notifier,
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};
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static struct pm_qos_object memory_bandwidth_pm_qos = {
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.constraints = &memory_bw_constraints,
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.name = "memory_bandwidth",
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};
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static struct pm_qos_object *pm_qos_array[] = {
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&null_pm_qos,
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&cpu_dma_pm_qos,
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&network_lat_pm_qos,
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&network_throughput_pm_qos,
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&memory_bandwidth_pm_qos,
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};
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static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
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size_t count, loff_t *f_pos);
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static ssize_t pm_qos_power_read(struct file *filp, char __user *buf,
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size_t count, loff_t *f_pos);
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static int pm_qos_power_open(struct inode *inode, struct file *filp);
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static int pm_qos_power_release(struct inode *inode, struct file *filp);
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static const struct file_operations pm_qos_power_fops = {
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.write = pm_qos_power_write,
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.read = pm_qos_power_read,
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.open = pm_qos_power_open,
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.release = pm_qos_power_release,
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.llseek = noop_llseek,
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};
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/* unlocked internal variant */
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static inline int pm_qos_get_value(struct pm_qos_constraints *c)
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{
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struct plist_node *node;
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int total_value = 0;
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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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case PM_QOS_SUM:
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plist_for_each(node, &c->list)
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total_value += node->prio;
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return total_value;
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default:
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/* runtime check for not using enum */
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BUG();
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return PM_QOS_DEFAULT_VALUE;
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}
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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 c->target_value;
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}
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static inline void pm_qos_set_value(struct pm_qos_constraints *c, s32 value)
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{
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c->target_value = value;
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}
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static int pm_qos_debug_show(struct seq_file *s, void *unused)
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{
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struct pm_qos_object *qos = (struct pm_qos_object *)s->private;
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struct pm_qos_constraints *c;
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struct pm_qos_request *req;
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char *type;
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unsigned long flags;
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int tot_reqs = 0;
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int active_reqs = 0;
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if (IS_ERR_OR_NULL(qos)) {
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pr_err("%s: bad qos param!\n", __func__);
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return -EINVAL;
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}
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c = qos->constraints;
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if (IS_ERR_OR_NULL(c)) {
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pr_err("%s: Bad constraints on qos?\n", __func__);
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return -EINVAL;
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}
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/* Lock to ensure we have a snapshot */
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spin_lock_irqsave(&pm_qos_lock, flags);
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if (plist_head_empty(&c->list)) {
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seq_puts(s, "Empty!\n");
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goto out;
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}
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switch (c->type) {
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case PM_QOS_MIN:
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type = "Minimum";
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break;
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case PM_QOS_MAX:
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type = "Maximum";
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break;
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case PM_QOS_SUM:
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type = "Sum";
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break;
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default:
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type = "Unknown";
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}
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plist_for_each_entry(req, &c->list, node) {
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char *state = "Default";
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if ((req->node).prio != c->default_value) {
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active_reqs++;
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state = "Active";
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}
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tot_reqs++;
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seq_printf(s, "%d: %d: %s\n", tot_reqs,
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(req->node).prio, state);
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}
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seq_printf(s, "Type=%s, Value=%d, Requests: active=%d / total=%d\n",
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type, pm_qos_get_value(c), active_reqs, tot_reqs);
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out:
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spin_unlock_irqrestore(&pm_qos_lock, flags);
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return 0;
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}
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DEFINE_SHOW_ATTRIBUTE(pm_qos_debug);
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/**
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* pm_qos_update_target - manages the constraints list and calls the notifiers
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* if needed
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* @c: constraints data struct
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* @node: request to add to the list, to update or to remove
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* @action: action to take on the constraints list
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* @value: value of the request to add or update
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*
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* This function returns 1 if the aggregated constraint value has changed, 0
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* 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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unsigned long flags;
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int prev_value, curr_value, new_value;
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int ret;
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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, we atomically remove, reinit
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* with new value and add, then see if the extremal
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* changed
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*/
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plist_del(node, &c->list);
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/* fall through */
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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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ret = 1;
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if (c->notifiers)
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blocking_notifier_call_chain(c->notifiers,
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(unsigned long)curr_value,
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NULL);
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} else {
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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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* 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 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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* Update the given set of PM QoS flags and call notifiers if the aggregate
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* value has changed. Returns 1 if the aggregate constraint value has changed,
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* 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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/* fall through */
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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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/**
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* pm_qos_request - returns current system wide qos expectation
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* @pm_qos_class: identification of which qos value is requested
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*
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* This function returns the current target value.
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*/
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int pm_qos_request(int pm_qos_class)
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{
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return pm_qos_read_value(pm_qos_array[pm_qos_class]->constraints);
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}
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EXPORT_SYMBOL_GPL(pm_qos_request);
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int pm_qos_request_active(struct pm_qos_request *req)
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{
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return req->pm_qos_class != 0;
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}
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EXPORT_SYMBOL_GPL(pm_qos_request_active);
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static void __pm_qos_update_request(struct pm_qos_request *req,
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s32 new_value)
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{
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trace_pm_qos_update_request(req->pm_qos_class, new_value);
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if (new_value != req->node.prio)
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pm_qos_update_target(
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pm_qos_array[req->pm_qos_class]->constraints,
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&req->node, PM_QOS_UPDATE_REQ, new_value);
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}
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/**
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* pm_qos_work_fn - the timeout handler of pm_qos_update_request_timeout
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* @work: work struct for the delayed work (timeout)
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*
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* This cancels the timeout request by falling back to the default at timeout.
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*/
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static void pm_qos_work_fn(struct work_struct *work)
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{
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struct pm_qos_request *req = container_of(to_delayed_work(work),
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struct pm_qos_request,
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work);
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__pm_qos_update_request(req, PM_QOS_DEFAULT_VALUE);
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}
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/**
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* pm_qos_add_request - inserts new qos request into the list
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* @req: pointer to a preallocated handle
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* @pm_qos_class: identifies which list of qos request to use
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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 pm_qos_class list of requested qos
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* performance characteristics. It recomputes the aggregate QoS expectations
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* for the pm_qos_class of parameters and initializes the 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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void pm_qos_add_request(struct pm_qos_request *req,
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int pm_qos_class, s32 value)
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{
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if (!req) /*guard against callers passing in null */
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return;
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if (pm_qos_request_active(req)) {
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WARN(1, KERN_ERR "pm_qos_add_request() called for already added request\n");
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return;
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}
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req->pm_qos_class = pm_qos_class;
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INIT_DELAYED_WORK(&req->work, pm_qos_work_fn);
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trace_pm_qos_add_request(pm_qos_class, value);
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pm_qos_update_target(pm_qos_array[pm_qos_class]->constraints,
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&req->node, PM_QOS_ADD_REQ, value);
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}
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EXPORT_SYMBOL_GPL(pm_qos_add_request);
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/**
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* pm_qos_update_request - modifies an existing qos request
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* @req : handle to list element holding a pm_qos request to use
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* @value: defines the qos request
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*
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* Updates an existing qos request for the pm_qos_class of parameters along
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* with updating the target pm_qos_class 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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void pm_qos_update_request(struct pm_qos_request *req,
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s32 new_value)
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{
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if (!req) /*guard against callers passing in null */
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return;
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if (!pm_qos_request_active(req)) {
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WARN(1, KERN_ERR "pm_qos_update_request() called for unknown object\n");
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return;
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}
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cancel_delayed_work_sync(&req->work);
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__pm_qos_update_request(req, new_value);
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}
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EXPORT_SYMBOL_GPL(pm_qos_update_request);
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/**
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* pm_qos_update_request_timeout - modifies an existing qos request temporarily.
|
|
* @req : handle to list element holding a pm_qos request to use
|
|
* @new_value: defines the temporal qos request
|
|
* @timeout_us: the effective duration of this qos request in usecs.
|
|
*
|
|
* After timeout_us, this qos request is cancelled automatically.
|
|
*/
|
|
void pm_qos_update_request_timeout(struct pm_qos_request *req, s32 new_value,
|
|
unsigned long timeout_us)
|
|
{
|
|
if (!req)
|
|
return;
|
|
if (WARN(!pm_qos_request_active(req),
|
|
"%s called for unknown object.", __func__))
|
|
return;
|
|
|
|
cancel_delayed_work_sync(&req->work);
|
|
|
|
trace_pm_qos_update_request_timeout(req->pm_qos_class,
|
|
new_value, timeout_us);
|
|
if (new_value != req->node.prio)
|
|
pm_qos_update_target(
|
|
pm_qos_array[req->pm_qos_class]->constraints,
|
|
&req->node, PM_QOS_UPDATE_REQ, new_value);
|
|
|
|
schedule_delayed_work(&req->work, usecs_to_jiffies(timeout_us));
|
|
}
|
|
|
|
/**
|
|
* pm_qos_remove_request - modifies an existing qos request
|
|
* @req: handle to request list element
|
|
*
|
|
* Will remove pm qos request from the list of constraints and
|
|
* recompute the current target value for the pm_qos_class. Call this
|
|
* on slow code paths.
|
|
*/
|
|
void pm_qos_remove_request(struct pm_qos_request *req)
|
|
{
|
|
if (!req) /*guard against callers passing in null */
|
|
return;
|
|
/* silent return to keep pcm code cleaner */
|
|
|
|
if (!pm_qos_request_active(req)) {
|
|
WARN(1, KERN_ERR "pm_qos_remove_request() called for unknown object\n");
|
|
return;
|
|
}
|
|
|
|
cancel_delayed_work_sync(&req->work);
|
|
|
|
trace_pm_qos_remove_request(req->pm_qos_class, PM_QOS_DEFAULT_VALUE);
|
|
pm_qos_update_target(pm_qos_array[req->pm_qos_class]->constraints,
|
|
&req->node, PM_QOS_REMOVE_REQ,
|
|
PM_QOS_DEFAULT_VALUE);
|
|
memset(req, 0, sizeof(*req));
|
|
}
|
|
EXPORT_SYMBOL_GPL(pm_qos_remove_request);
|
|
|
|
/**
|
|
* pm_qos_add_notifier - sets notification entry for changes to target value
|
|
* @pm_qos_class: identifies which qos target changes should be notified.
|
|
* @notifier: notifier block managed by caller.
|
|
*
|
|
* will register the notifier into a notification chain that gets called
|
|
* upon changes to the pm_qos_class target value.
|
|
*/
|
|
int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
|
|
{
|
|
int retval;
|
|
|
|
retval = blocking_notifier_chain_register(
|
|
pm_qos_array[pm_qos_class]->constraints->notifiers,
|
|
notifier);
|
|
|
|
return retval;
|
|
}
|
|
EXPORT_SYMBOL_GPL(pm_qos_add_notifier);
|
|
|
|
/**
|
|
* pm_qos_remove_notifier - deletes notification entry from chain.
|
|
* @pm_qos_class: identifies which qos target changes are notified.
|
|
* @notifier: notifier block to be removed.
|
|
*
|
|
* will remove the notifier from the notification chain that gets called
|
|
* upon changes to the pm_qos_class target value.
|
|
*/
|
|
int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
|
|
{
|
|
int retval;
|
|
|
|
retval = blocking_notifier_chain_unregister(
|
|
pm_qos_array[pm_qos_class]->constraints->notifiers,
|
|
notifier);
|
|
|
|
return retval;
|
|
}
|
|
EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
|
|
|
|
/* User space interface to PM QoS classes via misc devices */
|
|
static int register_pm_qos_misc(struct pm_qos_object *qos, struct dentry *d)
|
|
{
|
|
qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR;
|
|
qos->pm_qos_power_miscdev.name = qos->name;
|
|
qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops;
|
|
|
|
debugfs_create_file(qos->name, S_IRUGO, d, (void *)qos,
|
|
&pm_qos_debug_fops);
|
|
|
|
return misc_register(&qos->pm_qos_power_miscdev);
|
|
}
|
|
|
|
static int find_pm_qos_object_by_minor(int minor)
|
|
{
|
|
int pm_qos_class;
|
|
|
|
for (pm_qos_class = PM_QOS_CPU_DMA_LATENCY;
|
|
pm_qos_class < PM_QOS_NUM_CLASSES; pm_qos_class++) {
|
|
if (minor ==
|
|
pm_qos_array[pm_qos_class]->pm_qos_power_miscdev.minor)
|
|
return pm_qos_class;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
static int pm_qos_power_open(struct inode *inode, struct file *filp)
|
|
{
|
|
long pm_qos_class;
|
|
|
|
pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
|
|
if (pm_qos_class >= PM_QOS_CPU_DMA_LATENCY) {
|
|
struct pm_qos_request *req = kzalloc(sizeof(*req), GFP_KERNEL);
|
|
if (!req)
|
|
return -ENOMEM;
|
|
|
|
pm_qos_add_request(req, pm_qos_class, PM_QOS_DEFAULT_VALUE);
|
|
filp->private_data = req;
|
|
|
|
return 0;
|
|
}
|
|
return -EPERM;
|
|
}
|
|
|
|
static int pm_qos_power_release(struct inode *inode, struct file *filp)
|
|
{
|
|
struct pm_qos_request *req;
|
|
|
|
req = filp->private_data;
|
|
pm_qos_remove_request(req);
|
|
kfree(req);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
static ssize_t pm_qos_power_read(struct file *filp, char __user *buf,
|
|
size_t count, loff_t *f_pos)
|
|
{
|
|
s32 value;
|
|
unsigned long flags;
|
|
struct pm_qos_request *req = filp->private_data;
|
|
|
|
if (!req)
|
|
return -EINVAL;
|
|
if (!pm_qos_request_active(req))
|
|
return -EINVAL;
|
|
|
|
spin_lock_irqsave(&pm_qos_lock, flags);
|
|
value = pm_qos_get_value(pm_qos_array[req->pm_qos_class]->constraints);
|
|
spin_unlock_irqrestore(&pm_qos_lock, flags);
|
|
|
|
return simple_read_from_buffer(buf, count, f_pos, &value, sizeof(s32));
|
|
}
|
|
|
|
static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
|
|
size_t count, loff_t *f_pos)
|
|
{
|
|
s32 value;
|
|
struct pm_qos_request *req;
|
|
|
|
if (count == sizeof(s32)) {
|
|
if (copy_from_user(&value, buf, sizeof(s32)))
|
|
return -EFAULT;
|
|
} else {
|
|
int ret;
|
|
|
|
ret = kstrtos32_from_user(buf, count, 16, &value);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
req = filp->private_data;
|
|
pm_qos_update_request(req, value);
|
|
|
|
return count;
|
|
}
|
|
|
|
|
|
static int __init pm_qos_power_init(void)
|
|
{
|
|
int ret = 0;
|
|
int i;
|
|
struct dentry *d;
|
|
|
|
BUILD_BUG_ON(ARRAY_SIZE(pm_qos_array) != PM_QOS_NUM_CLASSES);
|
|
|
|
d = debugfs_create_dir("pm_qos", NULL);
|
|
|
|
for (i = PM_QOS_CPU_DMA_LATENCY; i < PM_QOS_NUM_CLASSES; i++) {
|
|
ret = register_pm_qos_misc(pm_qos_array[i], d);
|
|
if (ret < 0) {
|
|
pr_err("%s: %s setup failed\n",
|
|
__func__, pm_qos_array[i]->name);
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
late_initcall(pm_qos_power_init);
|