#include <linux/kernel.h>
  #include <linux/gfp.h>
  #include <linux/ide.h>
  
  int generic_ide_suspend(struct device *dev, pm_message_t mesg)
  {
  	ide_drive_t *drive = to_ide_device(dev);
  	ide_drive_t *pair = ide_get_pair_dev(drive);
  	ide_hwif_t *hwif = drive->hwif;
  	struct request *rq;
  	struct request_pm_state rqpm;
  	int ret;
  
  	if (ide_port_acpi(hwif)) {
  		/* call ACPI _GTM only once */
  		if ((drive->dn & 1) == 0 || pair == NULL)
  			ide_acpi_get_timing(hwif);
  	}
  
  	memset(&rqpm, 0, sizeof(rqpm));
  	rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
  	rq->cmd_type = REQ_TYPE_PM_SUSPEND;
  	rq->special = &rqpm;
  	rqpm.pm_step = IDE_PM_START_SUSPEND;
  	if (mesg.event == PM_EVENT_PRETHAW)
  		mesg.event = PM_EVENT_FREEZE;
  	rqpm.pm_state = mesg.event;
  
  	ret = blk_execute_rq(drive->queue, NULL, rq, 0);
  	blk_put_request(rq);
  
  	if (ret == 0 && ide_port_acpi(hwif)) {
  		/* call ACPI _PS3 only after both devices are suspended */
  		if ((drive->dn & 1) || pair == NULL)
  			ide_acpi_set_state(hwif, 0);
  	}
  
  	return ret;
  }
  
  int generic_ide_resume(struct device *dev)
  {
  	ide_drive_t *drive = to_ide_device(dev);
  	ide_drive_t *pair = ide_get_pair_dev(drive);
  	ide_hwif_t *hwif = drive->hwif;
  	struct request *rq;
  	struct request_pm_state rqpm;
  	int err;
  
  	if (ide_port_acpi(hwif)) {
  		/* call ACPI _PS0 / _STM only once */
  		if ((drive->dn & 1) == 0 || pair == NULL) {
  			ide_acpi_set_state(hwif, 1);
  			ide_acpi_push_timing(hwif);
  		}
  
  		ide_acpi_exec_tfs(drive);
  	}
  
  	memset(&rqpm, 0, sizeof(rqpm));
  	rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
  	rq->cmd_type = REQ_TYPE_PM_RESUME;
  	rq->cmd_flags |= REQ_PREEMPT;
  	rq->special = &rqpm;
  	rqpm.pm_step = IDE_PM_START_RESUME;
  	rqpm.pm_state = PM_EVENT_ON;
  
  	err = blk_execute_rq(drive->queue, NULL, rq, 1);
  	blk_put_request(rq);
  
  	if (err == 0 && dev->driver) {
  		struct ide_driver *drv = to_ide_driver(dev->driver);
  
  		if (drv->resume)
  			drv->resume(drive);
  	}
  
  	return err;
  }
  
  void ide_complete_power_step(ide_drive_t *drive, struct request *rq)
  {
  	struct request_pm_state *pm = rq->special;
  
  #ifdef DEBUG_PM
  	printk(KERN_INFO "%s: complete_power_step(step: %d)
  ",
  		drive->name, pm->pm_step);
  #endif
  	if (drive->media != ide_disk)
  		return;
  
  	switch (pm->pm_step) {
  	case IDE_PM_FLUSH_CACHE:	/* Suspend step 1 (flush cache) */
  		if (pm->pm_state == PM_EVENT_FREEZE)
  			pm->pm_step = IDE_PM_COMPLETED;
  		else
  			pm->pm_step = IDE_PM_STANDBY;
  		break;
  	case IDE_PM_STANDBY:		/* Suspend step 2 (standby) */
  		pm->pm_step = IDE_PM_COMPLETED;
  		break;
  	case IDE_PM_RESTORE_PIO:	/* Resume step 1 (restore PIO) */
  		pm->pm_step = IDE_PM_IDLE;
  		break;
  	case IDE_PM_IDLE:		/* Resume step 2 (idle)*/
  		pm->pm_step = IDE_PM_RESTORE_DMA;
  		break;
  	}
  }
  
  ide_startstop_t ide_start_power_step(ide_drive_t *drive, struct request *rq)
  {
  	struct request_pm_state *pm = rq->special;
  	struct ide_cmd cmd = { };
  
  	switch (pm->pm_step) {
  	case IDE_PM_FLUSH_CACHE:	/* Suspend step 1 (flush cache) */
  		if (drive->media != ide_disk)
  			break;
  		/* Not supported? Switch to next step now. */
  		if (ata_id_flush_enabled(drive->id) == 0 ||
  		    (drive->dev_flags & IDE_DFLAG_WCACHE) == 0) {
  			ide_complete_power_step(drive, rq);
  			return ide_stopped;
  		}
  		if (ata_id_flush_ext_enabled(drive->id))
  			cmd.tf.command = ATA_CMD_FLUSH_EXT;
  		else
  			cmd.tf.command = ATA_CMD_FLUSH;
  		goto out_do_tf;
  	case IDE_PM_STANDBY:		/* Suspend step 2 (standby) */
  		cmd.tf.command = ATA_CMD_STANDBYNOW1;
  		goto out_do_tf;
  	case IDE_PM_RESTORE_PIO:	/* Resume step 1 (restore PIO) */
  		ide_set_max_pio(drive);
  		/*
  		 * skip IDE_PM_IDLE for ATAPI devices
  		 */
  		if (drive->media != ide_disk)
  			pm->pm_step = IDE_PM_RESTORE_DMA;
  		else
  			ide_complete_power_step(drive, rq);
  		return ide_stopped;
  	case IDE_PM_IDLE:		/* Resume step 2 (idle) */
  		cmd.tf.command = ATA_CMD_IDLEIMMEDIATE;
  		goto out_do_tf;
  	case IDE_PM_RESTORE_DMA:	/* Resume step 3 (restore DMA) */
  		/*
  		 * Right now, all we do is call ide_set_dma(drive),
  		 * we could be smarter and check for current xfer_speed
  		 * in struct drive etc...
  		 */
  		if (drive->hwif->dma_ops == NULL)
  			break;
  		/*
  		 * TODO: respect IDE_DFLAG_USING_DMA
  		 */
  		ide_set_dma(drive);
  		break;
  	}
  
  	pm->pm_step = IDE_PM_COMPLETED;
  
  	return ide_stopped;
  
  out_do_tf:
  	cmd.valid.out.tf = IDE_VALID_OUT_TF | IDE_VALID_DEVICE;
  	cmd.valid.in.tf  = IDE_VALID_IN_TF  | IDE_VALID_DEVICE;
  	cmd.protocol = ATA_PROT_NODATA;
  
  	return do_rw_taskfile(drive, &cmd);
  }
  
  /**
   *	ide_complete_pm_rq - end the current Power Management request
   *	@drive: target drive
   *	@rq: request
   *
   *	This function cleans up the current PM request and stops the queue
   *	if necessary.
   */
  void ide_complete_pm_rq(ide_drive_t *drive, struct request *rq)
  {
  	struct request_queue *q = drive->queue;
  	struct request_pm_state *pm = rq->special;
  	unsigned long flags;
  
  	ide_complete_power_step(drive, rq);
  	if (pm->pm_step != IDE_PM_COMPLETED)
  		return;
  
  #ifdef DEBUG_PM
  	printk("%s: completing PM request, %s
  ", drive->name,
  	       (rq->cmd_type == REQ_TYPE_PM_SUSPEND) ? "suspend" : "resume");
  #endif
  	spin_lock_irqsave(q->queue_lock, flags);
  	if (rq->cmd_type == REQ_TYPE_PM_SUSPEND)
  		blk_stop_queue(q);
  	else
  		drive->dev_flags &= ~IDE_DFLAG_BLOCKED;
  	spin_unlock_irqrestore(q->queue_lock, flags);
  
  	drive->hwif->rq = NULL;
  
  	if (blk_end_request(rq, 0, 0))
  		BUG();
  }
  
  void ide_check_pm_state(ide_drive_t *drive, struct request *rq)
  {
  	struct request_pm_state *pm = rq->special;
  
  	if (rq->cmd_type == REQ_TYPE_PM_SUSPEND &&
  	    pm->pm_step == IDE_PM_START_SUSPEND)
  		/* Mark drive blocked when starting the suspend sequence. */
  		drive->dev_flags |= IDE_DFLAG_BLOCKED;
  	else if (rq->cmd_type == REQ_TYPE_PM_RESUME &&
  		 pm->pm_step == IDE_PM_START_RESUME) {
  		/*
  		 * The first thing we do on wakeup is to wait for BSY bit to
  		 * go away (with a looong timeout) as a drive on this hwif may
  		 * just be POSTing itself.
  		 * We do that before even selecting as the "other" device on
  		 * the bus may be broken enough to walk on our toes at this
  		 * point.
  		 */
  		ide_hwif_t *hwif = drive->hwif;
  		const struct ide_tp_ops *tp_ops = hwif->tp_ops;
  		struct request_queue *q = drive->queue;
  		unsigned long flags;
  		int rc;
  #ifdef DEBUG_PM
  		printk("%s: Wakeup request inited, waiting for !BSY...
  ", drive->name);
  #endif
  		rc = ide_wait_not_busy(hwif, 35000);
  		if (rc)
  			printk(KERN_WARNING "%s: bus not ready on wakeup
  ", drive->name);
  		tp_ops->dev_select(drive);
  		tp_ops->write_devctl(hwif, ATA_DEVCTL_OBS);
  		rc = ide_wait_not_busy(hwif, 100000);
  		if (rc)
  			printk(KERN_WARNING "%s: drive not ready on wakeup
  ", drive->name);
  
  		spin_lock_irqsave(q->queue_lock, flags);
  		blk_start_queue(q);
  		spin_unlock_irqrestore(q->queue_lock, flags);
  	}
  }