scsi_pm.c

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/*
 *  scsi_pm.c   Copyright (C) 2010 Alan Stern
 *
 *  SCSI dynamic Power Management
 *      Initial version: Alan Stern <[email protected]>
 */

#include <linux/pm_runtime.h>
#include <linux/export.h>
#include <linux/async.h>

#include <scsi/scsi.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_driver.h>
#include <scsi/scsi_host.h>

#include "scsi_priv.h"

static int scsi_dev_type_suspend(struct device *dev, pm_message_t msg)
{
    struct device_driver *drv;
    int err;

    err = scsi_device_quiesce(to_scsi_device(dev));
    if (err == 0) {
        drv = dev->driver;
        if (drv && drv->suspend) {
            err = drv->suspend(dev, msg);
            if (err)
                scsi_device_resume(to_scsi_device(dev));
        }
    }
    dev_dbg(dev, "scsi suspend: %d\n", err);
    return err;
}

static int scsi_dev_type_resume(struct device *dev)
{
    struct device_driver *drv;
    int err = 0;

    drv = dev->driver;
    if (drv && drv->resume)
        err = drv->resume(dev);
    scsi_device_resume(to_scsi_device(dev));
    dev_dbg(dev, "scsi resume: %d\n", err);
    return err;
}

#ifdef CONFIG_PM_SLEEP

static int scsi_bus_suspend_common(struct device *dev, pm_message_t msg)
{
    int err = 0;

    if (scsi_is_sdev_device(dev)) {
        /*
         * sd is the only high-level SCSI driver to implement runtime
         * PM, and sd treats runtime suspend, system suspend, and
         * system hibernate identically (but not system freeze).
         */
        if (pm_runtime_suspended(dev)) {
            if (msg.event == PM_EVENT_SUSPEND ||
                msg.event == PM_EVENT_HIBERNATE)
                return 0;   /* already suspended */

            /* wake up device so that FREEZE will succeed */
            pm_runtime_resume(dev);
        }
        err = scsi_dev_type_suspend(dev, msg);
    }
    return err;
}

static int scsi_bus_resume_common(struct device *dev)
{
    int err = 0;

    /*
     * Parent device may have runtime suspended as soon as
     * it is woken up during the system resume.
     *
     * Resume it on behalf of child.
     */
    pm_runtime_get_sync(dev->parent);

    if (scsi_is_sdev_device(dev))
        err = scsi_dev_type_resume(dev);
    if (err == 0) {
        pm_runtime_disable(dev);
        pm_runtime_set_active(dev);
        pm_runtime_enable(dev);
    }

    pm_runtime_put_sync(dev->parent);

    return err;
}

static int scsi_bus_prepare(struct device *dev)
{
    if (scsi_is_sdev_device(dev)) {
        /* sd probing uses async_schedule.  Wait until it finishes. */
        async_synchronize_full_domain(&scsi_sd_probe_domain);

    } else if (scsi_is_host_device(dev)) {
        /* Wait until async scanning is finished */
        scsi_complete_async_scans();
    }
    return 0;
}

static int scsi_bus_suspend(struct device *dev)
{
    return scsi_bus_suspend_common(dev, PMSG_SUSPEND);
}

static int scsi_bus_freeze(struct device *dev)
{
    return scsi_bus_suspend_common(dev, PMSG_FREEZE);
}

static int scsi_bus_poweroff(struct device *dev)
{
    return scsi_bus_suspend_common(dev, PMSG_HIBERNATE);
}

#else /* CONFIG_PM_SLEEP */

#define scsi_bus_resume_common      NULL
#define scsi_bus_prepare        NULL
#define scsi_bus_suspend        NULL
#define scsi_bus_freeze         NULL
#define scsi_bus_poweroff       NULL

#endif /* CONFIG_PM_SLEEP */

#ifdef CONFIG_PM_RUNTIME

static int scsi_runtime_suspend(struct device *dev)
{
    int err = 0;

    dev_dbg(dev, "scsi_runtime_suspend\n");
    if (scsi_is_sdev_device(dev)) {
        err = scsi_dev_type_suspend(dev, PMSG_AUTO_SUSPEND);
        if (err == -EAGAIN)
            pm_schedule_suspend(dev, jiffies_to_msecs(
                round_jiffies_up_relative(HZ/10)));
    }

    /* Insert hooks here for targets, hosts, and transport classes */

    return err;
}

static int scsi_runtime_resume(struct device *dev)
{
    int err = 0;

    dev_dbg(dev, "scsi_runtime_resume\n");
    if (scsi_is_sdev_device(dev))
        err = scsi_dev_type_resume(dev);

    /* Insert hooks here for targets, hosts, and transport classes */

    return err;
}

static int scsi_runtime_idle(struct device *dev)
{
    int err;

    dev_dbg(dev, "scsi_runtime_idle\n");

    /* Insert hooks here for targets, hosts, and transport classes */

    if (scsi_is_sdev_device(dev))
        err = pm_schedule_suspend(dev, 100);
    else
        err = pm_runtime_suspend(dev);
    return err;
}

int scsi_autopm_get_device(struct scsi_device *sdev)
{
    int err;

    err = pm_runtime_get_sync(&sdev->sdev_gendev);
    if (err < 0 && err !=-EACCES)
        pm_runtime_put_sync(&sdev->sdev_gendev);
    else
        err = 0;
    return err;
}
EXPORT_SYMBOL_GPL(scsi_autopm_get_device);

void scsi_autopm_put_device(struct scsi_device *sdev)
{
    pm_runtime_put_sync(&sdev->sdev_gendev);
}
EXPORT_SYMBOL_GPL(scsi_autopm_put_device);

void scsi_autopm_get_target(struct scsi_target *starget)
{
    pm_runtime_get_sync(&starget->dev);
}

void scsi_autopm_put_target(struct scsi_target *starget)
{
    pm_runtime_put_sync(&starget->dev);
}

int scsi_autopm_get_host(struct Scsi_Host *shost)
{
    int err;

    err = pm_runtime_get_sync(&shost->shost_gendev);
    if (err < 0 && err !=-EACCES)
        pm_runtime_put_sync(&shost->shost_gendev);
    else
        err = 0;
    return err;
}

void scsi_autopm_put_host(struct Scsi_Host *shost)
{
    pm_runtime_put_sync(&shost->shost_gendev);
}

#else

#define scsi_runtime_suspend    NULL
#define scsi_runtime_resume NULL
#define scsi_runtime_idle   NULL

#endif /* CONFIG_PM_RUNTIME */

const struct dev_pm_ops scsi_bus_pm_ops = {
    .prepare =      scsi_bus_prepare,
    .suspend =      scsi_bus_suspend,
    .resume =       scsi_bus_resume_common,
    .freeze =       scsi_bus_freeze,
    .thaw =         scsi_bus_resume_common,
    .poweroff =     scsi_bus_poweroff,
    .restore =      scsi_bus_resume_common,
    .runtime_suspend =  scsi_runtime_suspend,
    .runtime_resume =   scsi_runtime_resume,
    .runtime_idle =     scsi_runtime_idle,
};