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Commit 702aaf46 authored Jul 25, 2018 by Manu Gautam

USB: ci13xxx_udc: Avoid unclocked access if pm_runtime_get fails



If remote wakeup request is received during system resume where
resume_early is still processing, pm_runtime_get_sync returns
-EACCES error as runtime_pm for a device is disabled between
late_suspend and early_resume.
This results in runtime_get_sync failing to bring hardware out
of low power mode state followed by unclocked access of registers
as part of remote wakeup.

Fix this by retrying runtime_resume if pm_runtime_get_sync fails
with -EACCESS.

Change-Id: I73c0d0da57e40392d00793a5b3814dd04105ef63
Signed-off-by: Manu Gautam <mgautam@codeaurora.org>

parent fab1b6d5

drivers/usb/gadget/ci13xxx_udc.c

+24 −1

Original line number	Diff line number	Diff line
		@@ -1613,11 +1613,14 @@ done:
		}
		static DEVICE_ATTR(dtds, S_IWUSR, NULL, print_dtds);

		#define CI_PM_RESUME_RETRIES 5 /* Max Number of retries */

		static int ci13xxx_wakeup(struct usb_gadget *_gadget)
		{
		struct ci13xxx *udc = container_of(_gadget, struct ci13xxx, gadget);
		unsigned long flags;
		int ret = 0;
		static int retry_count;

		trace();

		@@ -1629,7 +1632,27 @@ static int ci13xxx_wakeup(struct usb_gadget *_gadget)
		}
		spin_unlock_irqrestore(udc->lock, flags);

		pm_runtime_get_sync(&_gadget->dev);
		ret = pm_runtime_get_sync(&_gadget->dev);
		if (ret) {
		/* pm_runtime_get_sync returns -EACCES error between
		* late_suspend and early_resume, wait for system resume to
		* finish and perform resume from work_queue again
		*/
		pr_debug("PM runtime get sync failed, ret %d\n", ret);
		if (ret == -EACCES) {
		pm_runtime_put_noidle(&_gadget->dev);
		if (retry_count == CI_PM_RESUME_RETRIES) {
		pr_err("pm_runtime_get_sync timed out\n");
		retry_count = 0;
		return 0;
		}
		retry_count++;
		schedule_delayed_work(&udc->rw_work,
		REMOTE_WAKEUP_DELAY);
		return 0;
		}
		}
		retry_count = 0;

		udc->udc_driver->notify_event(udc,
		CI13XXX_CONTROLLER_REMOTE_WAKEUP_EVENT);