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memstick: rtsx_usb_ms: Support runtime power management
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In order to let host's parent device, rtsx_usb, to use USB remote wake
up signaling to do card detection, it needs to be suspended. Hence it's
necessary to add runtime PM support for the memstick host.

To keep memstick host stays suspended when it's not in use, convert the
card detection function from kthread to delayed_work, which can be
scheduled when the host is resumed and can be canceled when the host is
suspended.

Put the device to suspend when there's no card and the power mode is
MEMSTICK_POWER_OFF.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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@khfeng @storulf
khfeng authored and storulf committed Dec 17, 2018
1 parent ba9d5f8 commit 6827ca5
Showing 1 changed file with 100 additions and 63 deletions.
163 changes: 100 additions & 63 deletions drivers/memstick/host/rtsx_usb_ms.c
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Original file line number Diff line number Diff line change
Expand Up @@ -40,15 +40,14 @@ struct rtsx_usb_ms {

struct mutex host_mutex;
struct work_struct handle_req;

struct task_struct *detect_ms;
struct completion detect_ms_exit;
struct delayed_work poll_card;

u8 ssc_depth;
unsigned int clock;
int power_mode;
unsigned char ifmode;
bool eject;
bool system_suspending;
};

static inline struct device *ms_dev(struct rtsx_usb_ms *host)
Expand Down Expand Up @@ -545,7 +544,7 @@ static void rtsx_usb_ms_handle_req(struct work_struct *work)
host->req->error);
}
} while (!rc);
pm_runtime_put(ms_dev(host));
pm_runtime_put_sync(ms_dev(host));
}

}
Expand Down Expand Up @@ -585,14 +584,14 @@ static int rtsx_usb_ms_set_param(struct memstick_host *msh,
break;

if (value == MEMSTICK_POWER_ON) {
pm_runtime_get_sync(ms_dev(host));
pm_runtime_get_noresume(ms_dev(host));
err = ms_power_on(host);
if (err)
pm_runtime_put_noidle(ms_dev(host));
} else if (value == MEMSTICK_POWER_OFF) {
err = ms_power_off(host);
if (host->msh->card)
if (!err)
pm_runtime_put_noidle(ms_dev(host));
else
pm_runtime_put(ms_dev(host));
} else
err = -EINVAL;
if (!err)
Expand Down Expand Up @@ -638,12 +637,16 @@ static int rtsx_usb_ms_set_param(struct memstick_host *msh,
}
out:
mutex_unlock(&ucr->dev_mutex);
pm_runtime_put(ms_dev(host));
pm_runtime_put_sync(ms_dev(host));

/* power-on delay */
if (param == MEMSTICK_POWER && value == MEMSTICK_POWER_ON)
if (param == MEMSTICK_POWER && value == MEMSTICK_POWER_ON) {
usleep_range(10000, 12000);

if (!host->eject)
schedule_delayed_work(&host->poll_card, 100);
}

dev_dbg(ms_dev(host), "%s: return = %d\n", __func__, err);
return err;
}
Expand All @@ -654,9 +657,24 @@ static int rtsx_usb_ms_suspend(struct device *dev)
struct rtsx_usb_ms *host = dev_get_drvdata(dev);
struct memstick_host *msh = host->msh;

dev_dbg(ms_dev(host), "--> %s\n", __func__);
/* Since we use rtsx_usb's resume callback to runtime resume its
* children to implement remote wakeup signaling, this causes
* rtsx_usb_ms' runtime resume callback runs after its suspend
* callback:
* rtsx_usb_ms_suspend()
* rtsx_usb_resume()
* -> rtsx_usb_ms_runtime_resume()
* -> memstick_detect_change()
*
* rtsx_usb_suspend()
*
* To avoid this, skip runtime resume/suspend if system suspend is
* underway.
*/

host->system_suspending = true;
memstick_suspend_host(msh);

return 0;
}

Expand All @@ -665,58 +683,85 @@ static int rtsx_usb_ms_resume(struct device *dev)
struct rtsx_usb_ms *host = dev_get_drvdata(dev);
struct memstick_host *msh = host->msh;

dev_dbg(ms_dev(host), "--> %s\n", __func__);

memstick_resume_host(msh);
host->system_suspending = false;

return 0;
}
#endif /* CONFIG_PM_SLEEP */

/*
* Thread function of ms card slot detection. The thread starts right after
* successful host addition. It stops while the driver removal function sets
* host->eject true.
*/
static int rtsx_usb_detect_ms_card(void *__host)
#ifdef CONFIG_PM
static int rtsx_usb_ms_runtime_suspend(struct device *dev)
{
struct rtsx_usb_ms *host = dev_get_drvdata(dev);

if (host->system_suspending)
return 0;

if (host->msh->card || host->power_mode != MEMSTICK_POWER_OFF)
return -EAGAIN;

return 0;
}

static int rtsx_usb_ms_runtime_resume(struct device *dev)
{
struct rtsx_usb_ms *host = dev_get_drvdata(dev);


if (host->system_suspending)
return 0;

memstick_detect_change(host->msh);

return 0;
}
#endif /* CONFIG_PM */

static const struct dev_pm_ops rtsx_usb_ms_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(rtsx_usb_ms_suspend, rtsx_usb_ms_resume)
SET_RUNTIME_PM_OPS(rtsx_usb_ms_runtime_suspend, rtsx_usb_ms_runtime_resume, NULL)
};


static void rtsx_usb_ms_poll_card(struct work_struct *work)
{
struct rtsx_usb_ms *host = (struct rtsx_usb_ms *)__host;
struct rtsx_usb_ms *host = container_of(work, struct rtsx_usb_ms,
poll_card.work);
struct rtsx_ucr *ucr = host->ucr;
u8 val = 0;
int err;
u8 val;

for (;;) {
pm_runtime_get_sync(ms_dev(host));
mutex_lock(&ucr->dev_mutex);

/* Check pending MS card changes */
err = rtsx_usb_read_register(ucr, CARD_INT_PEND, &val);
if (err) {
mutex_unlock(&ucr->dev_mutex);
goto poll_again;
}
if (host->eject || host->power_mode != MEMSTICK_POWER_ON)
return;

/* Clear the pending */
rtsx_usb_write_register(ucr, CARD_INT_PEND,
XD_INT | MS_INT | SD_INT,
XD_INT | MS_INT | SD_INT);
pm_runtime_get_sync(ms_dev(host));
mutex_lock(&ucr->dev_mutex);

/* Check pending MS card changes */
err = rtsx_usb_read_register(ucr, CARD_INT_PEND, &val);
if (err) {
mutex_unlock(&ucr->dev_mutex);
goto poll_again;
}

if (val & MS_INT) {
dev_dbg(ms_dev(host), "MS slot change detected\n");
memstick_detect_change(host->msh);
}
/* Clear the pending */
rtsx_usb_write_register(ucr, CARD_INT_PEND,
XD_INT | MS_INT | SD_INT,
XD_INT | MS_INT | SD_INT);

poll_again:
pm_runtime_put(ms_dev(host));
if (host->eject)
break;
mutex_unlock(&ucr->dev_mutex);

schedule_timeout_idle(HZ);
if (val & MS_INT) {
dev_dbg(ms_dev(host), "MS slot change detected\n");
memstick_detect_change(host->msh);
}

complete(&host->detect_ms_exit);
return 0;
poll_again:
pm_runtime_put_sync(ms_dev(host));

if (!host->eject && host->power_mode == MEMSTICK_POWER_ON)
schedule_delayed_work(&host->poll_card, 100);
}

static int rtsx_usb_ms_drv_probe(struct platform_device *pdev)
Expand Down Expand Up @@ -747,40 +792,36 @@ static int rtsx_usb_ms_drv_probe(struct platform_device *pdev)
mutex_init(&host->host_mutex);
INIT_WORK(&host->handle_req, rtsx_usb_ms_handle_req);

init_completion(&host->detect_ms_exit);
host->detect_ms = kthread_create(rtsx_usb_detect_ms_card, host,
"rtsx_usb_ms_%d", pdev->id);
if (IS_ERR(host->detect_ms)) {
dev_dbg(&(pdev->dev),
"Unable to create polling thread.\n");
err = PTR_ERR(host->detect_ms);
goto err_out;
}
INIT_DELAYED_WORK(&host->poll_card, rtsx_usb_ms_poll_card);

msh->request = rtsx_usb_ms_request;
msh->set_param = rtsx_usb_ms_set_param;
msh->caps = MEMSTICK_CAP_PAR4;

pm_runtime_enable(&pdev->dev);
pm_runtime_get_noresume(ms_dev(host));
pm_runtime_set_active(ms_dev(host));
pm_runtime_enable(ms_dev(host));

err = memstick_add_host(msh);
if (err)
goto err_out;

wake_up_process(host->detect_ms);
pm_runtime_put(ms_dev(host));

return 0;
err_out:
memstick_free_host(msh);
pm_runtime_disable(ms_dev(host));
pm_runtime_put_noidle(ms_dev(host));
return err;
}

static int rtsx_usb_ms_drv_remove(struct platform_device *pdev)
{
struct rtsx_usb_ms *host = platform_get_drvdata(pdev);
struct memstick_host *msh;
struct memstick_host *msh = host->msh;
int err;

msh = host->msh;
host->eject = true;
cancel_work_sync(&host->handle_req);

Expand All @@ -798,7 +839,6 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev)
}
mutex_unlock(&host->host_mutex);

wait_for_completion(&host->detect_ms_exit);
memstick_remove_host(msh);
memstick_free_host(msh);

Expand All @@ -817,9 +857,6 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev)
return 0;
}

static SIMPLE_DEV_PM_OPS(rtsx_usb_ms_pm_ops,
rtsx_usb_ms_suspend, rtsx_usb_ms_resume);

static struct platform_device_id rtsx_usb_ms_ids[] = {
{
.name = "rtsx_usb_ms",
Expand Down

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