// SPDX-License-Identifier: GPL-2.0-only
/*
 * kernel/power/main.c - PM subsystem core functionality.
 *
 * Copyright (c) 2003 Patrick Mochel
 * Copyright (c) 2003 Open Source Development Lab
 */

#include <linux/export.h>
#include <linux/kobject.h>
#include <linux/string.h>
#include <linux/pm-trace.h>
#include <linux/workqueue.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/suspend.h>
#include <linux/syscalls.h>

#include "power.h"

#ifdef CONFIG_PM_SLEEP

void lock_system_sleep(void)
{
        current->flags |= PF_FREEZER_SKIP;
        mutex_lock(&system_transition_mutex);
}
EXPORT_SYMBOL_GPL(lock_system_sleep);

void unlock_system_sleep(void)
{
        /*
         * Don't use freezer_count() because we don't want the call to
         * try_to_freeze() here.
         *
         * Reason:
         * Fundamentally, we just don't need it, because freezing condition
         * doesn't come into effect until we release the
         * system_transition_mutex lock, since the freezer always works with
         * system_transition_mutex held.
         *
         * More importantly, in the case of hibernation,
         * unlock_system_sleep() gets called in snapshot_read() and
         * snapshot_write() when the freezing condition is still in effect.
         * Which means, if we use try_to_freeze() here, it would make them
         * enter the refrigerator, thus causing hibernation to lockup.
         */
        current->flags &= ~PF_FREEZER_SKIP;
        mutex_unlock(&system_transition_mutex);
}
EXPORT_SYMBOL_GPL(unlock_system_sleep);

void ksys_sync_helper(void)
{
        ktime_t start;
        long elapsed_msecs;

        start = ktime_get();
        ksys_sync();
        elapsed_msecs = ktime_to_ms(ktime_sub(ktime_get(), start));
        pr_info("Filesystems sync: %ld.%03ld seconds\n",
                elapsed_msecs / MSEC_PER_SEC, elapsed_msecs % MSEC_PER_SEC);
}
EXPORT_SYMBOL_GPL(ksys_sync_helper);

/* Routines for PM-transition notifications */

static BLOCKING_NOTIFIER_HEAD(pm_chain_head);

int register_pm_notifier(struct notifier_block *nb)
{
        return blocking_notifier_chain_register(&pm_chain_head, nb);
}
EXPORT_SYMBOL_GPL(register_pm_notifier);

int unregister_pm_notifier(struct notifier_block *nb)
{
        return blocking_notifier_chain_unregister(&pm_chain_head, nb);
}
EXPORT_SYMBOL_GPL(unregister_pm_notifier);

int __pm_notifier_call_chain(unsigned long val, int nr_to_call, int *nr_calls)
{
        int ret;

        ret = __blocking_notifier_call_chain(&pm_chain_head, val, NULL,
                                                nr_to_call, nr_calls);

        return notifier_to_errno(ret);
}
int pm_notifier_call_chain(unsigned long val)
{
        return __pm_notifier_call_chain(val, -1, NULL);
}

/* If set, devices may be suspended and resumed asynchronously. */
int pm_async_enabled = 1;

static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr,
                             char *buf)
{
        return sprintf(buf, "%d\n", pm_async_enabled);
}

static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr,
                              const char *buf, size_t n)
{
        unsigned long val;

        if (kstrtoul(buf, 10, &val))
                return -EINVAL;

        if (val > 1)
                return -EINVAL;

        pm_async_enabled = val;
        return n;
}

power_attr(pm_async);

#ifdef CONFIG_SUSPEND
static ssize_t mem_sleep_show(struct kobject *kobj, struct kobj_attribute *attr,
                              char *buf)
{
        char *s = buf;
        suspend_state_t i;

        for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
                if (mem_sleep_states[i]) {
                        const char *label = mem_sleep_states[i];

                        if (mem_sleep_current == i)
                                s += sprintf(s, "[%s] ", label);
                        else
                                s += sprintf(s, "%s ", label);
                }

        /* Convert the last space to a newline if needed. */
        if (s != buf)
                *(s-1) = '\n';

        return (s - buf);
}

static suspend_state_t decode_suspend_state(const char *buf, size_t n)
{
        suspend_state_t state;
        char *p;
        int len;

        p = memchr(buf, '\n', n);
        len = p ? p - buf : n;

        for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
                const char *label = mem_sleep_states[state];

                if (label && len == strlen(label) && !strncmp(buf, label, len))
                        return state;
        }

        return PM_SUSPEND_ON;
}

static ssize_t mem_sleep_store(struct kobject *kobj, struct kobj_attribute *attr,
                               const char *buf, size_t n)
{
        suspend_state_t state;
        int error;

        error = pm_autosleep_lock();
        if (error)
                return error;

        if (pm_autosleep_state() > PM_SUSPEND_ON) {
                error = -EBUSY;
                goto out;
        }

        state = decode_suspend_state(buf, n);
        if (state < PM_SUSPEND_MAX && state > PM_SUSPEND_ON)
                mem_sleep_current = state;
        else
                error = -EINVAL;

 out:
        pm_autosleep_unlock();
        return error ? error : n;
}

power_attr(mem_sleep);
#endif /* CONFIG_SUSPEND */

#ifdef CONFIG_PM_SLEEP_DEBUG
int pm_test_level = TEST_NONE;

static const char * const pm_tests[__TEST_AFTER_LAST] = {
        [TEST_NONE] = "none",
        [TEST_CORE] = "core",
        [TEST_CPUS] = "processors",
        [TEST_PLATFORM] = "platform",
        [TEST_DEVICES] = "devices",
        [TEST_FREEZER] = "freezer",
};

static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
                                char *buf)
{
        char *s = buf;
        int level;

        for (level = TEST_FIRST; level <= TEST_MAX; level++)
                if (pm_tests[level]) {
                        if (level == pm_test_level)
                                s += sprintf(s, "[%s] ", pm_tests[level]);
                        else
                                s += sprintf(s, "%s ", pm_tests[level]);
                }

        if (s != buf)
                /* convert the last space to a newline */
                *(s-1) = '\n';

        return (s - buf);
}

static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
                                const char *buf, size_t n)
{
        const char * const *s;
        int level;
        char *p;
        int len;
        int error = -EINVAL;

        p = memchr(buf, '\n', n);
        len = p ? p - buf : n;

        lock_system_sleep();

        level = TEST_FIRST;
        for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
                if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
                        pm_test_level = level;
                        error = 0;
                        break;
                }

        unlock_system_sleep();

        return error ? error : n;
}

power_attr(pm_test);
#endif /* CONFIG_PM_SLEEP_DEBUG */

#ifdef CONFIG_DEBUG_FS
static char *suspend_step_name(enum suspend_stat_step step)
{
        switch (step) {
        case SUSPEND_FREEZE:
                return "freeze";
        case SUSPEND_PREPARE:
                return "prepare";
        case SUSPEND_SUSPEND:
                return "suspend";
        case SUSPEND_SUSPEND_NOIRQ:
                return "suspend_noirq";
        case SUSPEND_RESUME_NOIRQ:
                return "resume_noirq";
        case SUSPEND_RESUME:
                return "resume";
        default:
                return "";
        }
}

static int suspend_stats_show(struct seq_file *s, void *unused)
{
        int i, index, last_dev, last_errno, last_step;

        last_dev = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
        last_dev %= REC_FAILED_NUM;
        last_errno = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
        last_errno %= REC_FAILED_NUM;
        last_step = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
        last_step %= REC_FAILED_NUM;
        seq_printf(s, "%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n"
                        "%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n",
                        "success", suspend_stats.success,
                        "fail", suspend_stats.fail,
                        "failed_freeze", suspend_stats.failed_freeze,
                        "failed_prepare", suspend_stats.failed_prepare,
                        "failed_suspend", suspend_stats.failed_suspend,
                        "failed_suspend_late",
                                suspend_stats.failed_suspend_late,
                        "failed_suspend_noirq",
                                suspend_stats.failed_suspend_noirq,
                        "failed_resume", suspend_stats.failed_resume,
                        "failed_resume_early",
                                suspend_stats.failed_resume_early,
                        "failed_resume_noirq",
                                suspend_stats.failed_resume_noirq);
        seq_printf(s,   "failures:\n  last_failed_dev:\t%-s\n",
                        suspend_stats.failed_devs[last_dev]);
        for (i = 1; i < REC_FAILED_NUM; i++) {
                index = last_dev + REC_FAILED_NUM - i;
                index %= REC_FAILED_NUM;
                seq_printf(s, "\t\t\t%-s\n",
                        suspend_stats.failed_devs[index]);
        }
        seq_printf(s,   "  last_failed_errno:\t%-d\n",
                        suspend_stats.errno[last_errno]);
        for (i = 1; i < REC_FAILED_NUM; i++) {
                index = last_errno + REC_FAILED_NUM - i;
                index %= REC_FAILED_NUM;
                seq_printf(s, "\t\t\t%-d\n",
                        suspend_stats.errno[index]);
        }
        seq_printf(s,   "  last_failed_step:\t%-s\n",
                        suspend_step_name(
                                suspend_stats.failed_steps[last_step]));
        for (i = 1; i < REC_FAILED_NUM; i++) {
                index = last_step + REC_FAILED_NUM - i;
                index %= REC_FAILED_NUM;
                seq_printf(s, "\t\t\t%-s\n",
                        suspend_step_name(
                                suspend_stats.failed_steps[index]));
        }

        return 0;
}
DEFINE_SHOW_ATTRIBUTE(suspend_stats);

static int __init pm_debugfs_init(void)
{
        debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
                        NULL, NULL, &suspend_stats_fops);
        return 0;
}

late_initcall(pm_debugfs_init);
#endif /* CONFIG_DEBUG_FS */

#endif /* CONFIG_PM_SLEEP */

#ifdef CONFIG_PM_SLEEP_DEBUG
/*
 * pm_print_times: print time taken by devices to suspend and resume.
 *
 * show() returns whether printing of suspend and resume times is enabled.
 * store() accepts 0 or 1.  0 disables printing and 1 enables it.
 */
bool pm_print_times_enabled;

static ssize_t pm_print_times_show(struct kobject *kobj,
                                   struct kobj_attribute *attr, char *buf)
{
        return sprintf(buf, "%d\n", pm_print_times_enabled);
}

static ssize_t pm_print_times_store(struct kobject *kobj,
                                    struct kobj_attribute *attr,
                                    const char *buf, size_t n)
{
        unsigned long val;

        if (kstrtoul(buf, 10, &val))
                return -EINVAL;

        if (val > 1)
                return -EINVAL;

        pm_print_times_enabled = !!val;
        return n;
}

power_attr(pm_print_times);

static inline void pm_print_times_init(void)
{
        pm_print_times_enabled = !!initcall_debug;
}

static ssize_t pm_wakeup_irq_show(struct kobject *kobj,
                                        struct kobj_attribute *attr,
                                        char *buf)
{
        return pm_wakeup_irq ? sprintf(buf, "%u\n", pm_wakeup_irq) : -ENODATA;
}

power_attr_ro(pm_wakeup_irq);

bool pm_debug_messages_on __read_mostly;

static ssize_t pm_debug_messages_show(struct kobject *kobj,
                                      struct kobj_attribute *attr, char *buf)
{
        return sprintf(buf, "%d\n", pm_debug_messages_on);
}

static ssize_t pm_debug_messages_store(struct kobject *kobj,
                                       struct kobj_attribute *attr,
                                       const char *buf, size_t n)
{
        unsigned long val;

        if (kstrtoul(buf, 10, &val))
                return -EINVAL;

        if (val > 1)
                return -EINVAL;

        pm_debug_messages_on = !!val;
        return n;
}

power_attr(pm_debug_messages);

/**
 * __pm_pr_dbg - Print a suspend debug message to the kernel log.
 * @defer: Whether or not to use printk_deferred() to print the message.
 * @fmt: Message format.
 *
 * The message will be emitted if enabled through the pm_debug_messages
 * sysfs attribute.
 */
void __pm_pr_dbg(bool defer, const char *fmt, ...)
{
        struct va_format vaf;
        va_list args;

        if (!pm_debug_messages_on)
                return;

        va_start(args, fmt);

        vaf.fmt = fmt;
        vaf.va = &args;

        if (defer)
                printk_deferred(KERN_DEBUG "PM: %pV", &vaf);
        else
                printk(KERN_DEBUG "PM: %pV", &vaf);

        va_end(args);
}

#else /* !CONFIG_PM_SLEEP_DEBUG */
static inline void pm_print_times_init(void) {}
#endif /* CONFIG_PM_SLEEP_DEBUG */

struct kobject *power_kobj;

/**
 * state - control system sleep states.
 *
 * show() returns available sleep state labels, which may be "mem", "standby",
 * "freeze" and "disk" (hibernation).
 * See Documentation/admin-guide/pm/sleep-states.rst for a description of
 * what they mean.
 *
 * store() accepts one of those strings, translates it into the proper
 * enumerated value, and initiates a suspend transition.
 */
static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
                          char *buf)
{
        char *s = buf;
#ifdef CONFIG_SUSPEND
        suspend_state_t i;

        for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
                if (pm_states[i])
                        s += sprintf(s,"%s ", pm_states[i]);

#endif
        if (hibernation_available())
                s += sprintf(s, "disk ");
        if (s != buf)
                /* convert the last space to a newline */
                *(s-1) = '\n';
        return (s - buf);
}

static suspend_state_t decode_state(const char *buf, size_t n)
{
#ifdef CONFIG_SUSPEND
        suspend_state_t state;
#endif
        char *p;
        int len;

        p = memchr(buf, '\n', n);
        len = p ? p - buf : n;

        /* Check hibernation first. */
        if (len == 4 && !strncmp(buf, "disk", len))
                return PM_SUSPEND_MAX;

#ifdef CONFIG_SUSPEND
        for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
                const char *label = pm_states[state];

                if (label && len == strlen(label) && !strncmp(buf, label, len))
                        return state;
        }
#endif

        return PM_SUSPEND_ON;
}

static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
                           const char *buf, size_t n)
{
        suspend_state_t state;
        int error;

        error = pm_autosleep_lock();
        if (error)
                return error;

        if (pm_autosleep_state() > PM_SUSPEND_ON) {
                error = -EBUSY;
                goto out;
        }

        state = decode_state(buf, n);
        if (state < PM_SUSPEND_MAX) {
                if (state == PM_SUSPEND_MEM)
                        state = mem_sleep_current;

                error = pm_suspend(state);
        } else if (state == PM_SUSPEND_MAX) {
                error = hibernate();
        } else {
                error = -EINVAL;
        }

 out:
        pm_autosleep_unlock();
        return error ? error : n;
}

power_attr(state);

#ifdef CONFIG_PM_SLEEP
/*
 * The 'wakeup_count' attribute, along with the functions defined in
 * drivers/base/power/wakeup.c, provides a means by which wakeup events can be
 * handled in a non-racy way.
 *
 * If a wakeup event occurs when the system is in a sleep state, it simply is
 * woken up.  In turn, if an event that would wake the system up from a sleep
 * state occurs when it is undergoing a transition to that sleep state, the
 * transition should be aborted.  Moreover, if such an event occurs when the
 * system is in the working state, an attempt to start a transition to the
 * given sleep state should fail during certain period after the detection of
 * the event.  Using the 'state' attribute alone is not sufficient to satisfy
 * these requirements, because a wakeup event may occur exactly when 'state'
 * is being written to and may be delivered to user space right before it is
 * frozen, so the event will remain only partially processed until the system is
 * woken up by another event.  In particular, it won't cause the transition to
 * a sleep state to be aborted.
 *
 * This difficulty may be overcome if user space uses 'wakeup_count' before
 * writing to 'state'.  It first should read from 'wakeup_count' and store
 * the read value.  Then, after carrying out its own preparations for the system
 * transition to a sleep state, it should write the stored value to
 * 'wakeup_count'.  If that fails, at least one wakeup event has occurred since
 * 'wakeup_count' was read and 'state' should not be written to.  Otherwise, it
 * is allowed to write to 'state', but the transition will be aborted if there
 * are any wakeup events detected after 'wakeup_count' was written to.
 */

static ssize_t wakeup_count_show(struct kobject *kobj,
                                struct kobj_attribute *attr,
                                char *buf)
{
        unsigned int val;

        return pm_get_wakeup_count(&val, true) ?
                sprintf(buf, "%u\n", val) : -EINTR;
}

static ssize_t wakeup_count_store(struct kobject *kobj,
                                struct kobj_attribute *attr,
                                const char *buf, size_t n)
{
        unsigned int val;
        int error;

        error = pm_autosleep_lock();
        if (error)
                return error;

        if (pm_autosleep_state() > PM_SUSPEND_ON) {
                error = -EBUSY;
                goto out;
        }

        error = -EINVAL;
        if (sscanf(buf, "%u", &val) == 1) {
                if (pm_save_wakeup_count(val))
                        error = n;
                else
                        pm_print_active_wakeup_sources();
        }

 out:
        pm_autosleep_unlock();
        return error;
}

power_attr(wakeup_count);

#ifdef CONFIG_PM_AUTOSLEEP
static ssize_t autosleep_show(struct kobject *kobj,
                              struct kobj_attribute *attr,
                              char *buf)
{
        suspend_state_t state = pm_autosleep_state();

        if (state == PM_SUSPEND_ON)
                return sprintf(buf, "off\n");

#ifdef CONFIG_SUSPEND
        if (state < PM_SUSPEND_MAX)
                return sprintf(buf, "%s\n", pm_states[state] ?
                                        pm_states[state] : "error");
#endif
#ifdef CONFIG_HIBERNATION
        return sprintf(buf, "disk\n");
#else
        return sprintf(buf, "error");
#endif
}

static ssize_t autosleep_store(struct kobject *kobj,
                               struct kobj_attribute *attr,
                               const char *buf, size_t n)
{
        suspend_state_t state = decode_state(buf, n);
        int error;

        if (state == PM_SUSPEND_ON
            && strcmp(buf, "off") && strcmp(buf, "off\n"))
                return -EINVAL;

        if (state == PM_SUSPEND_MEM)
                state = mem_sleep_current;

        error = pm_autosleep_set_state(state);
        return error ? error : n;
}

power_attr(autosleep);
#endif /* CONFIG_PM_AUTOSLEEP */

#ifdef CONFIG_PM_WAKELOCKS
static ssize_t wake_lock_show(struct kobject *kobj,
                              struct kobj_attribute *attr,
                              char *buf)
{
        return pm_show_wakelocks(buf, true);
}

static ssize_t wake_lock_store(struct kobject *kobj,
                               struct kobj_attribute *attr,
                               const char *buf, size_t n)
{
        int error = pm_wake_lock(buf);
        return error ? error : n;
}

power_attr(wake_lock);

static ssize_t wake_unlock_show(struct kobject *kobj,
                                struct kobj_attribute *attr,
                                char *buf)
{
        return pm_show_wakelocks(buf, false);
}

static ssize_t wake_unlock_store(struct kobject *kobj,
                                 struct kobj_attribute *attr,
                                 const char *buf, size_t n)
{
        int error = pm_wake_unlock(buf);
        return error ? error : n;
}

power_attr(wake_unlock);

#endif /* CONFIG_PM_WAKELOCKS */
#endif /* CONFIG_PM_SLEEP */

#ifdef CONFIG_PM_TRACE
int pm_trace_enabled;

static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
                             char *buf)
{
        return sprintf(buf, "%d\n", pm_trace_enabled);
}

static ssize_t
pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
               const char *buf, size_t n)
{
        int val;

        if (sscanf(buf, "%d", &val) == 1) {
                pm_trace_enabled = !!val;
                if (pm_trace_enabled) {
                        pr_warn("PM: Enabling pm_trace changes system date and time during resume.\n"
                                "PM: Correct system time has to be restored manually after resume.\n");
                }
                return n;
        }
        return -EINVAL;
}

power_attr(pm_trace);

static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
                                       struct kobj_attribute *attr,
                                       char *buf)
{
        return show_trace_dev_match(buf, PAGE_SIZE);
}

power_attr_ro(pm_trace_dev_match);

#endif /* CONFIG_PM_TRACE */

#ifdef CONFIG_FREEZER
static ssize_t pm_freeze_timeout_show(struct kobject *kobj,
                                      struct kobj_attribute *attr, char *buf)
{
        return sprintf(buf, "%u\n", freeze_timeout_msecs);
}

static ssize_t pm_freeze_timeout_store(struct kobject *kobj,
                                       struct kobj_attribute *attr,
                                       const char *buf, size_t n)
{
        unsigned long val;

        if (kstrtoul(buf, 10, &val))
                return -EINVAL;

        freeze_timeout_msecs = val;
        return n;
}

power_attr(pm_freeze_timeout);

#endif  /* CONFIG_FREEZER*/

static struct attribute * g[] = {
        &state_attr.attr,
#ifdef CONFIG_PM_TRACE
        &pm_trace_attr.attr,
        &pm_trace_dev_match_attr.attr,
#endif
#ifdef CONFIG_PM_SLEEP
        &pm_async_attr.attr,
        &wakeup_count_attr.attr,
#ifdef CONFIG_SUSPEND
        &mem_sleep_attr.attr,
#endif
#ifdef CONFIG_PM_AUTOSLEEP
        &autosleep_attr.attr,
#endif
#ifdef CONFIG_PM_WAKELOCKS
        &wake_lock_attr.attr,
        &wake_unlock_attr.attr,
#endif
#ifdef CONFIG_PM_SLEEP_DEBUG
        &pm_test_attr.attr,
        &pm_print_times_attr.attr,
        &pm_wakeup_irq_attr.attr,
        &pm_debug_messages_attr.attr,
#endif
#endif
#ifdef CONFIG_FREEZER
        &pm_freeze_timeout_attr.attr,
#endif
        NULL,
};

static const struct attribute_group attr_group = {
        .attrs = g,
};

struct workqueue_struct *pm_wq;
EXPORT_SYMBOL_GPL(pm_wq);

static int __init pm_start_workqueue(void)
{
        pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);

        return pm_wq ? 0 : -ENOMEM;
}

static int __init pm_init(void)
{
        int error = pm_start_workqueue();
        if (error)
                return error;
        hibernate_image_size_init();
        hibernate_reserved_size_init();
        pm_states_init();
        power_kobj = kobject_create_and_add("power", NULL);
        if (!power_kobj)
                return -ENOMEM;
        error = sysfs_create_group(power_kobj, &attr_group);
        if (error)
                return error;
        pm_print_times_init();
        return pm_autosleep_init();
}

core_initcall(pm_init);