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