memstick: rtsx_usb_ms: Manage runtime PM when accessing the device

BugLink: http://bugs.launchpad.net/bugs/1637510

commit 9158cb29 upstream.

Accesses to the rtsx usb device, which is the parent of the rtsx memstick
device, must not be done unless it's runtime resumed. This is currently not
the case and it could trigger various errors.

Fix this by properly deal with runtime PM in this regards. This means
making sure the device is runtime resumed, when serving requests via the
->request() callback or changing settings via the ->set_param() callbacks.

Cc: Ritesh Raj Sarraf <rrs@researchut.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

drivers/memstick/host/rtsx_usb_ms.c

@@ -524,6 +524,7 @@ static void rtsx_usb_ms_handle_req(struct work_struct *work)
 	int rc;
 
 	if (!host->req) {
+		pm_runtime_get_sync(ms_dev(host));
 		do {
 			rc = memstick_next_req(msh, &host->req);
 			dev_dbg(ms_dev(host), "next req %d\n", rc);
@@ -544,6 +545,7 @@ static void rtsx_usb_ms_handle_req(struct work_struct *work)
 						host->req->error);
 			}
 		} while (!rc);
+		pm_runtime_put(ms_dev(host));
 	}
 
 }
@@ -570,6 +572,7 @@ static int rtsx_usb_ms_set_param(struct memstick_host *msh,
 	dev_dbg(ms_dev(host), "%s: param = %d, value = %d\n",
 			__func__, param, value);
 
+	pm_runtime_get_sync(ms_dev(host));
 	mutex_lock(&ucr->dev_mutex);
 
 	err = rtsx_usb_card_exclusive_check(ucr, RTSX_USB_MS_CARD);
@@ -635,6 +638,7 @@ static int rtsx_usb_ms_set_param(struct memstick_host *msh,
 	}
 out:
 	mutex_unlock(&ucr->dev_mutex);
+	pm_runtime_put(ms_dev(host));
 
 	/* power-on delay */
 	if (param == MEMSTICK_POWER && value == MEMSTICK_POWER_ON)