/*
   *	scsi_pm.c	Copyright (C) 2010 Alan Stern
   *
   *	SCSI dynamic Power Management
   *		Initial version: Alan Stern <stern@rowland.harvard.edu>
   */
  
  #include <linux/pm_runtime.h>

  #include <linux/export.h>

  #include <linux/async.h>

  
  #include <scsi/scsi.h>
  #include <scsi/scsi_device.h>
  #include <scsi/scsi_driver.h>
  #include <scsi/scsi_host.h>
  
  #include "scsi_priv.h"

  #ifdef CONFIG_PM_SLEEP

  static int do_scsi_suspend(struct device *dev, const struct dev_pm_ops *pm)

  {

  	return pm && pm->suspend ? pm->suspend(dev) : 0;
  }
  
  static int do_scsi_freeze(struct device *dev, const struct dev_pm_ops *pm)
  {
  	return pm && pm->freeze ? pm->freeze(dev) : 0;
  }
  
  static int do_scsi_poweroff(struct device *dev, const struct dev_pm_ops *pm)
  {
  	return pm && pm->poweroff ? pm->poweroff(dev) : 0;
  }
  
  static int do_scsi_resume(struct device *dev, const struct dev_pm_ops *pm)
  {
  	return pm && pm->resume ? pm->resume(dev) : 0;
  }
  
  static int do_scsi_thaw(struct device *dev, const struct dev_pm_ops *pm)
  {
  	return pm && pm->thaw ? pm->thaw(dev) : 0;
  }
  
  static int do_scsi_restore(struct device *dev, const struct dev_pm_ops *pm)
  {
  	return pm && pm->restore ? pm->restore(dev) : 0;
  }
  
  static int scsi_dev_type_suspend(struct device *dev,
  		int (*cb)(struct device *, const struct dev_pm_ops *))
  {
  	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;

  	int err;

  	/* flush pending in-flight resume operations, suspend is synchronous */
  	async_synchronize_full_domain(&scsi_sd_pm_domain);

  	err = scsi_device_quiesce(to_scsi_device(dev));
  	if (err == 0) {

  		err = cb(dev, pm);
  		if (err)
  			scsi_device_resume(to_scsi_device(dev));

  	}
  	dev_dbg(dev, "scsi suspend: %d
  ", err);
  	return err;
  }

  static int scsi_dev_type_resume(struct device *dev,
  		int (*cb)(struct device *, const struct dev_pm_ops *))

  {

  	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;

  	int err = 0;

  	err = cb(dev, pm);

  	scsi_device_resume(to_scsi_device(dev));
  	dev_dbg(dev, "scsi resume: %d
  ", err);

  
  	if (err == 0) {
  		pm_runtime_disable(dev);
  		pm_runtime_set_active(dev);
  		pm_runtime_enable(dev);
  	}

  	return err;
  }

  static int

  scsi_bus_suspend_common(struct device *dev,
  		int (*cb)(struct device *, const struct dev_pm_ops *))

  {
  	int err = 0;

  	if (scsi_is_sdev_device(dev)) {
  		/*

  		 * All the high-level SCSI drivers that implement runtime
  		 * PM treat runtime suspend, system suspend, and system

  		 * hibernate nearly identically. In all cases the requirements
  		 * for runtime suspension are stricter.

  		 */

  		if (pm_runtime_suspended(dev))
  			return 0;

  		err = scsi_dev_type_suspend(dev, cb);

  	}

  	return err;
  }

  static void async_sdev_resume(void *dev, async_cookie_t cookie)

  {

  	scsi_dev_type_resume(dev, do_scsi_resume);
  }

  static void async_sdev_thaw(void *dev, async_cookie_t cookie)
  {
  	scsi_dev_type_resume(dev, do_scsi_thaw);
  }

  static void async_sdev_restore(void *dev, async_cookie_t cookie)
  {
  	scsi_dev_type_resume(dev, do_scsi_restore);
  }
  
  static int scsi_bus_resume_common(struct device *dev,
  		int (*cb)(struct device *, const struct dev_pm_ops *))
  {
  	async_func_t fn;
  
  	if (!scsi_is_sdev_device(dev))
  		fn = NULL;
  	else if (cb == do_scsi_resume)
  		fn = async_sdev_resume;
  	else if (cb == do_scsi_thaw)
  		fn = async_sdev_thaw;
  	else if (cb == do_scsi_restore)
  		fn = async_sdev_restore;
  	else
  		fn = NULL;
  
  	if (fn) {
  		async_schedule_domain(fn, dev, &scsi_sd_pm_domain);
  
  		/*
  		 * If a user has disabled async probing a likely reason
  		 * is due to a storage enclosure that does not inject
  		 * staggered spin-ups.  For safety, make resume
  		 * synchronous as well in that case.
  		 */
  		if (strncmp(scsi_scan_type, "async", 5) != 0)
  			async_synchronize_full_domain(&scsi_sd_pm_domain);
  	} else {

  		pm_runtime_disable(dev);
  		pm_runtime_set_active(dev);
  		pm_runtime_enable(dev);
  	}

  	return 0;

  }

  static int scsi_bus_prepare(struct device *dev)
  {
  	if (scsi_is_sdev_device(dev)) {
  		/* sd probing uses async_schedule.  Wait until it finishes. */

  		async_synchronize_full_domain(&scsi_sd_probe_domain);

  
  	} else if (scsi_is_host_device(dev)) {
  		/* Wait until async scanning is finished */
  		scsi_complete_async_scans();
  	}
  	return 0;
  }

  static int scsi_bus_suspend(struct device *dev)
  {

  	return scsi_bus_suspend_common(dev, do_scsi_suspend);

  }
  
  static int scsi_bus_resume(struct device *dev)
  {

  	return scsi_bus_resume_common(dev, do_scsi_resume);

  }
  
  static int scsi_bus_freeze(struct device *dev)
  {

  	return scsi_bus_suspend_common(dev, do_scsi_freeze);

  }
  
  static int scsi_bus_thaw(struct device *dev)
  {

  	return scsi_bus_resume_common(dev, do_scsi_thaw);

  }
  
  static int scsi_bus_poweroff(struct device *dev)
  {

  	return scsi_bus_suspend_common(dev, do_scsi_poweroff);

  }
  
  static int scsi_bus_restore(struct device *dev)
  {

  	return scsi_bus_resume_common(dev, do_scsi_restore);

  }
  
  #else /* CONFIG_PM_SLEEP */

  #define scsi_bus_prepare		NULL

  #define scsi_bus_suspend		NULL

  #define scsi_bus_resume			NULL

  #define scsi_bus_freeze			NULL

  #define scsi_bus_thaw			NULL

  #define scsi_bus_poweroff		NULL

  #define scsi_bus_restore		NULL

  
  #endif /* CONFIG_PM_SLEEP */

  static int sdev_runtime_suspend(struct device *dev)

  {

  	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
  	struct scsi_device *sdev = to_scsi_device(dev);

  	int err = 0;

  	err = blk_pre_runtime_suspend(sdev->request_queue);
  	if (err)
  		return err;
  	if (pm && pm->runtime_suspend)

  		err = pm->runtime_suspend(dev);

  	blk_post_runtime_suspend(sdev->request_queue, err);

  	return err;
  }

  static int scsi_runtime_suspend(struct device *dev)
  {
  	int err = 0;
  
  	dev_dbg(dev, "scsi_runtime_suspend
  ");

  	if (scsi_is_sdev_device(dev))
  		err = sdev_runtime_suspend(dev);

  
  	/* Insert hooks here for targets, hosts, and transport classes */
  
  	return err;
  }

  static int sdev_runtime_resume(struct device *dev)

  {

  	struct scsi_device *sdev = to_scsi_device(dev);
  	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;

  	int err = 0;

  	blk_pre_runtime_resume(sdev->request_queue);
  	if (pm && pm->runtime_resume)

  		err = pm->runtime_resume(dev);

  	blk_post_runtime_resume(sdev->request_queue, err);

  	return err;
  }

  static int scsi_runtime_resume(struct device *dev)
  {
  	int err = 0;

  
  	dev_dbg(dev, "scsi_runtime_resume
  ");
  	if (scsi_is_sdev_device(dev))

  		err = sdev_runtime_resume(dev);

  
  	/* Insert hooks here for targets, hosts, and transport classes */
  
  	return err;
  }
  
  static int scsi_runtime_idle(struct device *dev)
  {

  	dev_dbg(dev, "scsi_runtime_idle
  ");
  
  	/* Insert hooks here for targets, hosts, and transport classes */

  	if (scsi_is_sdev_device(dev)) {

  		pm_runtime_mark_last_busy(dev);
  		pm_runtime_autosuspend(dev);
  		return -EBUSY;

  	}

  	return 0;

  }
  
  int scsi_autopm_get_device(struct scsi_device *sdev)
  {
  	int	err;
  
  	err = pm_runtime_get_sync(&sdev->sdev_gendev);

  	if (err < 0 && err !=-EACCES)

  		pm_runtime_put_sync(&sdev->sdev_gendev);

  	else

  		err = 0;
  	return err;
  }
  EXPORT_SYMBOL_GPL(scsi_autopm_get_device);
  
  void scsi_autopm_put_device(struct scsi_device *sdev)
  {
  	pm_runtime_put_sync(&sdev->sdev_gendev);
  }
  EXPORT_SYMBOL_GPL(scsi_autopm_put_device);
  
  void scsi_autopm_get_target(struct scsi_target *starget)
  {
  	pm_runtime_get_sync(&starget->dev);
  }
  
  void scsi_autopm_put_target(struct scsi_target *starget)
  {
  	pm_runtime_put_sync(&starget->dev);
  }
  
  int scsi_autopm_get_host(struct Scsi_Host *shost)
  {
  	int	err;
  
  	err = pm_runtime_get_sync(&shost->shost_gendev);

  	if (err < 0 && err !=-EACCES)

  		pm_runtime_put_sync(&shost->shost_gendev);

  	else

  		err = 0;
  	return err;
  }
  
  void scsi_autopm_put_host(struct Scsi_Host *shost)
  {
  	pm_runtime_put_sync(&shost->shost_gendev);
  }

  const struct dev_pm_ops scsi_bus_pm_ops = {

  	.prepare =		scsi_bus_prepare,

  	.suspend =		scsi_bus_suspend,

  	.resume =		scsi_bus_resume,

  	.freeze =		scsi_bus_freeze,

  	.thaw =			scsi_bus_thaw,

  	.poweroff =		scsi_bus_poweroff,

  	.restore =		scsi_bus_restore,

  	.runtime_suspend =	scsi_runtime_suspend,
  	.runtime_resume =	scsi_runtime_resume,
  	.runtime_idle =		scsi_runtime_idle,

  };