ide-park.c revision 4abdc6ee7c47a1a6e12f95717e461baeebee5df7 
1#include <linux/kernel.h>
2#include <linux/ide.h>
3#include <linux/jiffies.h>
4#include <linux/blkdev.h>
5
6DECLARE_WAIT_QUEUE_HEAD(ide_park_wq);
7
8static void issue_park_cmd(ide_drive_t *drive, unsigned long timeout)
9{
10	struct request_queue *q = drive->queue;
11	struct request *rq;
12	int rc;
13
14	timeout += jiffies;
15	spin_lock_irq(&ide_lock);
16	if (drive->dev_flags & IDE_DFLAG_PARKED) {
17		ide_hwgroup_t *hwgroup = drive->hwif->hwgroup;
18		int reset_timer;
19
20		reset_timer = time_before(timeout, drive->sleep);
21		drive->sleep = timeout;
22		wake_up_all(&ide_park_wq);
23		if (reset_timer && hwgroup->sleeping &&
24		    del_timer(&hwgroup->timer)) {
25			hwgroup->sleeping = 0;
26			hwgroup->busy = 0;
27			blk_start_queueing(q);
28		}
29		spin_unlock_irq(&ide_lock);
30		return;
31	}
32	spin_unlock_irq(&ide_lock);
33
34	rq = blk_get_request(q, READ, __GFP_WAIT);
35	rq->cmd[0] = REQ_PARK_HEADS;
36	rq->cmd_len = 1;
37	rq->cmd_type = REQ_TYPE_SPECIAL;
38	rq->special = &timeout;
39	rc = blk_execute_rq(q, NULL, rq, 1);
40	blk_put_request(rq);
41	if (rc)
42		goto out;
43
44	/*
45	 * Make sure that *some* command is sent to the drive after the
46	 * timeout has expired, so power management will be reenabled.
47	 */
48	rq = blk_get_request(q, READ, GFP_NOWAIT);
49	if (unlikely(!rq))
50		goto out;
51
52	rq->cmd[0] = REQ_UNPARK_HEADS;
53	rq->cmd_len = 1;
54	rq->cmd_type = REQ_TYPE_SPECIAL;
55	elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 1);
56
57out:
58	return;
59}
60
61ssize_t ide_park_show(struct device *dev, struct device_attribute *attr,
62		      char *buf)
63{
64	ide_drive_t *drive = to_ide_device(dev);
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(&ide_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(&ide_lock);
79
80	return snprintf(buf, 20, "%u\n", msecs);
81}
82
83ssize_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}
122