text: // SPDX-License-Identifier: GPL-2.0
  #include <linux/kernel.h>
  #include <linux/gfp.h>
  #include <linux/ide.h>
  #include <linux/jiffies.h>
  #include <linux/blkdev.h>
  
  DECLARE_WAIT_QUEUE_HEAD(ide_park_wq);
  
  static void issue_park_cmd(ide_drive_t *drive, unsigned long timeout)
  {
  	ide_hwif_t *hwif = drive->hwif;
  	struct request_queue *q = drive->queue;
  	struct request *rq;
  	int rc;
  
  	timeout += jiffies;
  	spin_lock_irq(&hwif->lock);
  	if (drive->dev_flags & IDE_DFLAG_PARKED) {
  		int reset_timer = time_before(timeout, drive->sleep);
  		int start_queue = 0;
  
  		drive->sleep = timeout;
  		wake_up_all(&ide_park_wq);
  		if (reset_timer && del_timer(&hwif->timer))
  			start_queue = 1;
  		spin_unlock_irq(&hwif->lock);
  
  		if (start_queue)
  			blk_mq_run_hw_queues(q, true);
  		return;
  	}
  	spin_unlock_irq(&hwif->lock);
  
  	rq = blk_get_request(q, REQ_OP_DRV_IN, 0);
  	scsi_req(rq)->cmd[0] = REQ_PARK_HEADS;
  	scsi_req(rq)->cmd_len = 1;
  	ide_req(rq)->type = ATA_PRIV_MISC;
  	ide_req(rq)->special = &timeout;
  	blk_execute_rq(NULL, rq, 1);
  	rc = scsi_req(rq)->result ? -EIO : 0;
  	blk_put_request(rq);
  	if (rc)
  		goto out;
  
  	/*
  	 * Make sure that *some* command is sent to the drive after the
  	 * timeout has expired, so power management will be reenabled.
  	 */
  	rq = blk_get_request(q, REQ_OP_DRV_IN, BLK_MQ_REQ_NOWAIT);
  	if (IS_ERR(rq))
  		goto out;
  
  	scsi_req(rq)->cmd[0] = REQ_UNPARK_HEADS;
  	scsi_req(rq)->cmd_len = 1;
  	ide_req(rq)->type = ATA_PRIV_MISC;
  	spin_lock_irq(&hwif->lock);
  	ide_insert_request_head(drive, rq);
  	spin_unlock_irq(&hwif->lock);
  
  out:
  	return;
  }
  
  ide_startstop_t ide_do_park_unpark(ide_drive_t *drive, struct request *rq)
  {
  	struct ide_cmd cmd;
  	struct ide_taskfile *tf = &cmd.tf;
  
  	memset(&cmd, 0, sizeof(cmd));
  	if (scsi_req(rq)->cmd[0] == REQ_PARK_HEADS) {
  		drive->sleep = *(unsigned long *)ide_req(rq)->special;
  		drive->dev_flags |= IDE_DFLAG_SLEEPING;
  		tf->command = ATA_CMD_IDLEIMMEDIATE;
  		tf->feature = 0x44;
  		tf->lbal = 0x4c;
  		tf->lbam = 0x4e;
  		tf->lbah = 0x55;
  		cmd.valid.out.tf = IDE_VALID_OUT_TF | IDE_VALID_DEVICE;
  		cmd.valid.in.tf  = IDE_VALID_IN_TF  | IDE_VALID_DEVICE;
  	} else		/* cmd == REQ_UNPARK_HEADS */
  		tf->command = ATA_CMD_CHK_POWER;
  
  	cmd.tf_flags |= IDE_TFLAG_CUSTOM_HANDLER;
  	cmd.protocol = ATA_PROT_NODATA;
  
  	cmd.rq = rq;
  
  	return do_rw_taskfile(drive, &cmd);
  }
  
  ssize_t ide_park_show(struct device *dev, struct device_attribute *attr,
  		      char *buf)
  {
  	ide_drive_t *drive = to_ide_device(dev);
  	ide_hwif_t *hwif = drive->hwif;
  	unsigned long now;
  	unsigned int msecs;
  
  	if (drive->dev_flags & IDE_DFLAG_NO_UNLOAD)
  		return -EOPNOTSUPP;
  
  	spin_lock_irq(&hwif->lock);
  	now = jiffies;
  	if (drive->dev_flags & IDE_DFLAG_PARKED &&
  	    time_after(drive->sleep, now))
  		msecs = jiffies_to_msecs(drive->sleep - now);
  	else
  		msecs = 0;
  	spin_unlock_irq(&hwif->lock);
  
  	return snprintf(buf, 20, "%u\n", msecs);
  }
  
  ssize_t ide_park_store(struct device *dev, struct device_attribute *attr,
  		       const char *buf, size_t len)
  {
  #define MAX_PARK_TIMEOUT 30000
  	ide_drive_t *drive = to_ide_device(dev);
  	long int input;
  	int rc;
  
  	rc = kstrtol(buf, 10, &input);
  	if (rc)
  		return rc;
  	if (input < -2)
  		return -EINVAL;
  	if (input > MAX_PARK_TIMEOUT) {
  		input = MAX_PARK_TIMEOUT;
  		rc = -EOVERFLOW;
  	}
  
  	mutex_lock(&ide_setting_mtx);
  	if (input >= 0) {
  		if (drive->dev_flags & IDE_DFLAG_NO_UNLOAD)
  			rc = -EOPNOTSUPP;
  		else if (input || drive->dev_flags & IDE_DFLAG_PARKED)
  			issue_park_cmd(drive, msecs_to_jiffies(input));
  	} else {
  		if (drive->media == ide_disk)
  			switch (input) {
  			case -1:
  				drive->dev_flags &= ~IDE_DFLAG_NO_UNLOAD;
  				break;
  			case -2:
  				drive->dev_flags |= IDE_DFLAG_NO_UNLOAD;
  				break;
  			}
  		else
  			rc = -EOPNOTSUPP;
  	}
  	mutex_unlock(&ide_setting_mtx);
  
  	return rc ? rc : len;
  }
  