ide-park.c

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#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_run_queue(q);
        return;
    }
    spin_unlock_irq(&hwif->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);

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 (rq->cmd[0] == REQ_PARK_HEADS) {
        drive->sleep = *(unsigned long *)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 = 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;
}