ide: Implement disk shock protection support (v4)

[pandora-kernel.git] / drivers / ide / ide-park.c

diff --git a/drivers/ide/ide-park.c b/drivers/ide/ide-park.c
new file mode 100644 (file)
index 0000000..03b00e5
--- /dev/null
+++ b/drivers/ide/ide-park.c
@@ -0,0 +1,121 @@
+#include <linux/kernel.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)
+{
+       struct request_queue *q = drive->queue;
+       struct request *rq;
+       int rc;
+
+       timeout += jiffies;
+       spin_lock_irq(&ide_lock);
+       if (drive->dev_flags & IDE_DFLAG_PARKED) {
+               ide_hwgroup_t *hwgroup = drive->hwif->hwgroup;
+               int reset_timer;
+
+               reset_timer = time_before(timeout, drive->sleep);
+               drive->sleep = timeout;
+               wake_up_all(&ide_park_wq);
+               if (reset_timer && hwgroup->sleeping &&
+                   del_timer(&hwgroup->timer)) {
+                       hwgroup->sleeping = 0;
+                       hwgroup->busy = 0;
+                       blk_start_queueing(q);
+               }
+               spin_unlock_irq(&ide_lock);
+               return;
+       }
+       spin_unlock_irq(&ide_lock);
+
+       rq = blk_get_request(q, READ, __GFP_WAIT);
+       rq->cmd[0] = REQ_PARK_HEADS;
+       rq->cmd_len = 1;
+       rq->cmd_type = REQ_TYPE_SPECIAL;
+       rq->special = &timeout;
+       rc = blk_execute_rq(q, NULL, rq, 1);
+       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, READ, GFP_NOWAIT);
+       if (unlikely(!rq))
+               goto out;
+
+       rq->cmd[0] = REQ_UNPARK_HEADS;
+       rq->cmd_len = 1;
+       rq->cmd_type = REQ_TYPE_SPECIAL;
+       elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 1);
+
+out:
+       return;
+}
+
+ssize_t ide_park_show(struct device *dev, struct device_attribute *attr,
+                     char *buf)
+{
+       ide_drive_t *drive = to_ide_device(dev);
+       unsigned long now;
+       unsigned int msecs;
+
+       if (drive->dev_flags & IDE_DFLAG_NO_UNLOAD)
+               return -EOPNOTSUPP;
+
+       spin_lock_irq(&ide_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(&ide_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 = strict_strtol(buf, 10, &input);
+       if (rc || 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;
+}