/*
   * kernel/power/main.c - PM subsystem core functionality.
   *
   * Copyright (c) 2003 Patrick Mochel
   * Copyright (c) 2003 Open Source Development Lab

   *

   * This file is released under the GPLv2
   *
   */

  #include <linux/export.h>

  #include <linux/kobject.h>
  #include <linux/string.h>

  #include <linux/resume-trace.h>

  #include <linux/workqueue.h>

  #include <linux/debugfs.h>
  #include <linux/seq_file.h>

  
  #include "power.h"

  DEFINE_MUTEX(pm_mutex);

  #ifdef CONFIG_PM_SLEEP

  /* 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 ret = blocking_notifier_call_chain(&pm_chain_head, val, NULL);
  
  	return notifier_to_errno(ret);

  }

  /* 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
  ", 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 (strict_strtoul(buf, 10, &val))
  		return -EINVAL;
  
  	if (val > 1)
  		return -EINVAL;
  
  	pm_async_enabled = val;
  	return n;
  }
  
  power_attr(pm_async);

  #ifdef CONFIG_PM_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) = '
  ';
  
  	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);
  	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_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
  %s: %d
  %s: %d
  %s: %d
  "
  			"%s: %d
  %s: %d
  %s: %d
  %s: %d
  ",
  			"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_noirq",
  				suspend_stats.failed_suspend_noirq,
  			"failed_resume", suspend_stats.failed_resume,
  			"failed_resume_noirq",
  				suspend_stats.failed_resume_noirq);
  	seq_printf(s,	"failures:
    last_failed_dev:\t%-s
  ",
  			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
  ",
  			suspend_stats.failed_devs[index]);
  	}
  	seq_printf(s,	"  last_failed_errno:\t%-d
  ",
  			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
  ",
  			suspend_stats.errno[index]);
  	}
  	seq_printf(s,	"  last_failed_step:\t%-s
  ",
  			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
  ",
  			suspend_step_name(
  				suspend_stats.failed_steps[index]));
  	}
  
  	return 0;
  }
  
  static int suspend_stats_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, suspend_stats_show, NULL);
  }
  
  static const struct file_operations suspend_stats_operations = {
  	.open           = suspend_stats_open,
  	.read           = seq_read,
  	.llseek         = seq_lseek,
  	.release        = single_release,
  };
  
  static int __init pm_debugfs_init(void)
  {
  	debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
  			NULL, NULL, &suspend_stats_operations);
  	return 0;
  }
  
  late_initcall(pm_debugfs_init);
  #endif /* CONFIG_DEBUG_FS */

  #endif /* CONFIG_PM_SLEEP */

  struct kobject *power_kobj;

  
  /**
   *	state - control system power state.
   *
   *	show() returns what states are supported, which is hard-coded to
   *	'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
   *	'disk' (Suspend-to-Disk).
   *

   *	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

  	int i;

  
  	for (i = 0; i < PM_SUSPEND_MAX; i++) {

  		if (pm_states[i] && valid_state(i))
  			s += sprintf(s,"%s ", pm_states[i]);

  	}

  #endif

  #ifdef CONFIG_HIBERNATION

  	s += sprintf(s, "%s
  ", "disk");
  #else
  	if (s != buf)
  		/* convert the last space to a newline */
  		*(s-1) = '
  ';
  #endif

  	return (s - buf);
  }

  static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
  			   const char *buf, size_t n)

  {

  #ifdef CONFIG_SUSPEND

  	suspend_state_t state = PM_SUSPEND_STANDBY;

  	const char * const *s;

  #endif

  	char *p;

  	int len;

  	int error = -EINVAL;

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

  	/* First, check if we are requested to hibernate */

  	if (len == 4 && !strncmp(buf, "disk", len)) {

  		error = hibernate();

  		goto Exit;

  	}

  #ifdef CONFIG_SUSPEND

  	for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {

  		if (*s && len == strlen(*s) && !strncmp(buf, *s, len))

  			break;
  	}

  	if (state < PM_SUSPEND_MAX && *s) {

  		error = enter_state(state);

  		if (error) {
  			suspend_stats.fail++;
  			dpm_save_failed_errno(error);
  		} else
  			suspend_stats.success++;

  	}

  #endif
  
   Exit:

  	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) ? sprintf(buf, "%u
  ", val) : -EINTR;

  }
  
  static ssize_t wakeup_count_store(struct kobject *kobj,
  				struct kobj_attribute *attr,
  				const char *buf, size_t n)
  {

  	unsigned int val;

  	if (sscanf(buf, "%u", &val) == 1) {

  		if (pm_save_wakeup_count(val))
  			return n;
  	}
  	return -EINVAL;
  }
  
  power_attr(wakeup_count);
  #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
  ", 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;
  		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);
  }
  
  static ssize_t
  pm_trace_dev_match_store(struct kobject *kobj, struct kobj_attribute *attr,
  			 const char *buf, size_t n)
  {
  	return -EINVAL;
  }
  
  power_attr(pm_trace_dev_match);

  #endif /* CONFIG_PM_TRACE */

  
  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_PM_DEBUG

  	&pm_test_attr.attr,
  #endif

  #endif

  	NULL,
  };

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

  #ifdef CONFIG_PM_RUNTIME
  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;
  }
  #else
  static inline int pm_start_workqueue(void) { return 0; }
  #endif

  static int __init pm_init(void)
  {

  	int error = pm_start_workqueue();
  	if (error)
  		return error;

  	hibernate_image_size_init();

  	hibernate_reserved_size_init();

  	power_kobj = kobject_create_and_add("power", NULL);
  	if (!power_kobj)

  		return -ENOMEM;

  	return sysfs_create_group(power_kobj, &attr_group);

  }
  
  core_initcall(pm_init);