drivers/ide/ide-park.c

   1 #include <linux/kernel.h>
   2 #include <linux/ide.h>
   3 #include <linux/jiffies.h>
   4 #include <linux/blkdev.h>
   5
   6 DECLARE_WAIT_QUEUE_HEAD(ide_park_wq);
   7
   8 static void issue_park_cmd(ide_drive_t *drive, unsigned long timeout)
   9 {
  10         ide_hwgroup_t *hwgroup = drive->hwif->hwgroup;
  11         struct request_queue *q = drive->queue;
  12         struct request *rq;
  13         int rc;
  14
  15         timeout += jiffies;
  16         spin_lock_irq(&hwgroup->lock);
  17         if (drive->dev_flags & IDE_DFLAG_PARKED) {
  18                 int reset_timer = time_before(timeout, drive->sleep);
  19                 int start_queue = 0;
  20
  21                 drive->sleep = timeout;
  22                 wake_up_all(&ide_park_wq);
  23                 if (reset_timer && del_timer(&hwgroup->timer))
  24                         start_queue = 1;
  25                 spin_unlock_irq(&hwgroup->lock);
  26
  27                 if (start_queue) {
  28                         spin_lock_irq(q->queue_lock);
  29                         blk_start_queueing(q);
  30                         spin_unlock_irq(q->queue_lock);
  31                 }
  32                 return;
  33         }
  34         spin_unlock_irq(&hwgroup->lock);
  35
  36         rq = blk_get_request(q, READ, __GFP_WAIT);
  37         rq->cmd[0] = REQ_PARK_HEADS;
  38         rq->cmd_len = 1;
  39         rq->cmd_type = REQ_TYPE_SPECIAL;
  40         rq->special = &timeout;
  41         rc = blk_execute_rq(q, NULL, rq, 1);
  42         blk_put_request(rq);
  43         if (rc)
  44                 goto out;
  45
  46         /*
  47          * Make sure that *some* command is sent to the drive after the
  48          * timeout has expired, so power management will be reenabled.
  49          */
  50         rq = blk_get_request(q, READ, GFP_NOWAIT);
  51         if (unlikely(!rq))
  52                 goto out;
  53
  54         rq->cmd[0] = REQ_UNPARK_HEADS;
  55         rq->cmd_len = 1;
  56         rq->cmd_type = REQ_TYPE_SPECIAL;
  57         elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 1);
  58
  59 out:
  60         return;
  61 }
  62
  63 ssize_t ide_park_show(struct device *dev, struct device_attribute *attr,
  64                       char *buf)
  65 {
  66         ide_drive_t *drive = to_ide_device(dev);
  67         ide_hwgroup_t *hwgroup = drive->hwif->hwgroup;
  68         unsigned long now;
  69         unsigned int msecs;
  70
  71         if (drive->dev_flags & IDE_DFLAG_NO_UNLOAD)
  72                 return -EOPNOTSUPP;
  73
  74         spin_lock_irq(&hwgroup->lock);
  75         now = jiffies;
  76         if (drive->dev_flags & IDE_DFLAG_PARKED &&
  77             time_after(drive->sleep, now))
  78                 msecs = jiffies_to_msecs(drive->sleep - now);
  79         else
  80                 msecs = 0;
  81         spin_unlock_irq(&hwgroup->lock);
  82
  83         return snprintf(buf, 20, "%u\n", msecs);
  84 }
  85
  86 ssize_t ide_park_store(struct device *dev, struct device_attribute *attr,
  87                        const char *buf, size_t len)
  88 {
  89 #define MAX_PARK_TIMEOUT 30000
  90         ide_drive_t *drive = to_ide_device(dev);
  91         long int input;
  92         int rc;
  93
  94         rc = strict_strtol(buf, 10, &input);
  95         if (rc || input < -2)
  96                 return -EINVAL;
  97         if (input > MAX_PARK_TIMEOUT) {
  98                 input = MAX_PARK_TIMEOUT;
  99                 rc = -EOVERFLOW;
 100         }
 101
 102         mutex_lock(&ide_setting_mtx);
 103         if (input >= 0) {
 104                 if (drive->dev_flags & IDE_DFLAG_NO_UNLOAD)
 105                         rc = -EOPNOTSUPP;
 106                 else if (input || drive->dev_flags & IDE_DFLAG_PARKED)
 107                         issue_park_cmd(drive, msecs_to_jiffies(input));
 108         } else {
 109                 if (drive->media == ide_disk)
 110                         switch (input) {
 111                         case -1:
 112                                 drive->dev_flags &= ~IDE_DFLAG_NO_UNLOAD;
 113                                 break;
 114                         case -2:
 115                                 drive->dev_flags |= IDE_DFLAG_NO_UNLOAD;
 116                                 break;
 117                         }
 118                 else
 119                         rc = -EOPNOTSUPP;
 120         }
 121         mutex_unlock(&ide_setting_mtx);
 122
 123         return rc ? rc : len;
 124 }