path: root/drivers/base/power/wakeup.c

// SPDX-License-Identifier: GPL-2.0
/*
 * drivers/base/power/wakeup.c - System wakeup events framework
 *
 * Copyright (c) 2010 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
 */
#define pr_fmt(fmt) "PM: " fmt

#include <linux/device.h>
#include <linux/slab.h>
#include <linux/sched/signal.h>
#include <linux/capability.h>
#include <linux/export.h>
#include <linux/suspend.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/pm_wakeirq.h>
#include <trace/events/power.h>

#include "power.h"

#define list_for_each_entry_rcu_locked(pos, head, member) \
	list_for_each_entry_rcu(pos, head, member, \
		srcu_read_lock_held(&wakeup_srcu))
/*
 * If set, the suspend/hibernate code will abort transitions to a sleep state
 * if wakeup events are registered during or immediately before the transition.
 */
bool events_check_enabled __read_mostly;

/* First wakeup IRQ seen by the kernel in the last cycle. */
static unsigned int wakeup_irq[2] __read_mostly;
static DEFINE_RAW_SPINLOCK(wakeup_irq_lock);

/* If greater than 0 and the system is suspending, terminate the suspend. */
static atomic_t pm_abort_suspend __read_mostly;

/*
 * Combined counters of registered wakeup events and wakeup events in progress.
 * They need to be modified together atomically, so it's better to use one
 * atomic variable to hold them both.
 */
static atomic_t combined_event_count = ATOMIC_INIT(0);

#define IN_PROGRESS_BITS	(sizeof(int) * 4)
#define MAX_IN_PROGRESS		((1 << IN_PROGRESS_BITS) - 1)

static void split_counters(unsigned int *cnt, unsigned int *inpr)
{
	unsigned int comb = atomic_read(&combined_event_count);

	*cnt = (comb >> IN_PROGRESS_BITS);
	*inpr = comb & MAX_IN_PROGRESS;
}

/* A preserved old value of the events counter. */
static unsigned int saved_count;

static DEFINE_RAW_SPINLOCK(events_lock);

static void pm_wakeup_timer_fn(struct timer_list *t);

static LIST_HEAD(wakeup_sources);

static DECLARE_WAIT_QUEUE_HEAD(wakeup_count_wait_queue);

DEFINE_STATIC_SRCU(wakeup_srcu);

static struct wakeup_source deleted_ws = {
	.name = "deleted",
	.lock =  __SPIN_LOCK_UNLOCKED(deleted_ws.lock),
};

static DEFINE_IDA(wakeup_ida);

/**
 * wakeup_source_create - Create a struct wakeup_source object.
 * @name: Name of the new wakeup source.
 */
struct wakeup_source *wakeup_source_create(const char *name)
{
	struct wakeup_source *ws;
	const char *ws_name;
	int id;

	ws = kzalloc(sizeof(*ws), GFP_KERNEL);
	if (!ws)
		goto err_ws;

	ws_name = kstrdup_const(name, GFP_KERNEL);
	if (!ws_name)
		goto err_name;
	ws->name = ws_name;

	id = ida_alloc(&wakeup_ida, GFP_KERNEL);
	if (id < 0)
		goto err_id;
	ws->id = id;

	return ws;

err_id:
	kfree_const(ws->name);
err_name:
	kfree(ws);
err_ws:
	return NULL;
}
EXPORT_SYMBOL_GPL(wakeup_source_create);

/*
 * Record wakeup_source statistics being deleted into a dummy wakeup_source.
 */
static void wakeup_source_record(struct wakeup_source *ws)
{
	unsigned long flags;

	spin_lock_irqsave(&deleted_ws.lock, flags);

	if (ws->event_count) {
		deleted_ws.total_time =
			ktime_add(deleted_ws.total_time, ws->total_time);
		deleted_ws.prevent_sleep_time =
			ktime_add(deleted_ws.prevent_sleep_time,
				  ws->prevent_sleep_time);
		deleted_ws.max_time =
			ktime_compare(deleted_ws.max_time, ws->max_time) > 0 ?
				deleted_ws.max_time : ws->max_time;
		deleted_ws.event_count += ws->event_count;
		deleted_ws.active_count += ws->active_count;
		deleted_ws.relax_count += ws->relax_count;
		deleted_ws.expire_count += ws->expire_count;
		deleted_ws.wakeup_count += ws->wakeup_count;
	}

	spin_unlock_irqrestore(&deleted_ws.lock, flags);
}

static void wakeup_source_free(struct wakeup_source *ws)
{
	ida_free(&wakeup_ida, ws->id);
	kfree_const(ws->name);
	kfree(ws);
}

/**
 * wakeup_source_destroy - Destroy a struct wakeup_source object.
 * @ws: Wakeup source to destroy.
 *
 * Use only for wakeup source objects created with wakeup_source_create().
 */
void wakeup_source_destroy(struct wakeup_source *ws)
{
	if (!ws)
		return;

	__pm_relax(ws);
	wakeup_source_record(ws);
	wakeup_source_free(ws);
}
EXPORT_SYMBOL_GPL(wakeup_source_destroy);

/**
 * wakeup_source_add - Add given object to the list of wakeup sources.
 * @ws: Wakeup source object to add to the list.
 */