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Commit 559bd47c authored by Jack Pham's avatar Jack Pham
Browse files

usb: dwc3-msm: Simplify restart_usb_host_mode() callback 



Convert restart_usb_host_mode() into a generic blocking_sync()
callback which simply ensures that any pending role switches are
fully flushed before proceeding with the next extcon_set_state()
call. Move the responsibility of stopping/restarting host mode
with the speed to the PD policy engine instead.

This fixes a couple of possible race scenarios:
1) stopping host mode needs to be fully completed before allowing
   DisplayPort to initialize as it may require exclusive use of
   the PHY.

2) data role swap followed by entering DisplayPort alt mode in
   which it determines it needs 4-lane configuration. The
   back-to-back start peripheral, stop peripheral and start
   host may overlap if they are not serialized.

Change-Id: Ic29b74ae3e22f69f67e73aba59d211b81eb70de0
Signed-off-by: default avatarJack Pham <jackp@codeaurora.org>
parent 0c075d52

drivers/usb/dwc3/dwc3-msm.c

+28 −40
Original line number Diff line number Diff line
@@ -181,7 +181,7 @@ struct extcon_nb { 
	int			idx;

	struct notifier_block	vbus_nb;

	struct notifier_block	id_nb;

	struct notifier_block	host_restart_nb;

	struct notifier_block	blocking_sync_nb;

};



/* Input bits to state machine (mdwc->inputs) */
@@ -294,7 +294,7 @@ static void dwc3_pwr_event_handler(struct dwc3_msm *mdwc); 
static int dwc3_msm_gadget_vbus_draw(struct dwc3_msm *mdwc, unsigned int mA);

static void dwc3_msm_notify_event(struct dwc3 *dwc, unsigned int event,

						unsigned int value);

static int dwc3_restart_usb_host_mode(struct notifier_block *nb,

static int dwc3_usb_blocking_sync(struct notifier_block *nb,

					unsigned long event, void *ptr);



/**
@@ -3094,10 +3094,10 @@ static int dwc3_msm_extcon_register(struct dwc3_msm *mdwc) 
		if (ret < 0)

			check_id_state = false;



		mdwc->extcon[idx].host_restart_nb.notifier_call =

					dwc3_restart_usb_host_mode;

		mdwc->extcon[idx].blocking_sync_nb.notifier_call =

					dwc3_usb_blocking_sync;

		extcon_register_blocking_notifier(edev, EXTCON_USB_HOST,

					&mdwc->extcon[idx].host_restart_nb);

					&mdwc->extcon[idx].blocking_sync_nb);



		/* Update initial VBUS/ID state */

		if (check_vbus_state && extcon_get_state(edev, EXTCON_USB))
@@ -4087,58 +4087,46 @@ static int dwc3_otg_start_peripheral(struct dwc3_msm *mdwc, int on) 
	return 0;

}



/* speed: 0 - USB_SPEED_HIGH, 1 - USB_SPEED_SUPER */

static int dwc3_restart_usb_host_mode(struct notifier_block *nb,

static int dwc3_usb_blocking_sync(struct notifier_block *nb,

				unsigned long event, void *ptr)

{

	struct dwc3 *dwc;

	struct extcon_dev *edev = ptr;

	struct extcon_nb *enb = container_of(nb, struct extcon_nb,

						host_restart_nb);

						blocking_sync_nb);

	struct dwc3_msm *mdwc = enb->mdwc;

	int ret = -EINVAL, usb_speed;

	int ret = 0;



	if (!edev || !mdwc)

		return NOTIFY_DONE;



	dwc = platform_get_drvdata(mdwc->dwc3);



	usb_speed = (event == 0 ? USB_SPEED_HIGH : USB_SPEED_SUPER);

	if (dwc->maximum_speed == usb_speed)

		return 0;



	dbg_event(0xFF, "fw_restarthost", 0);

	dbg_event(0xFF, "fw_blocksync", 0);

	flush_work(&mdwc->resume_work);

	flush_delayed_work(&mdwc->sm_work);



	if (!mdwc->in_host_mode)

		goto err;



	dbg_event(0xFF, "stop_host_mode", dwc->maximum_speed);

	ret = dwc3_otg_start_host(mdwc, 0);

	if (ret)

		goto err;

	if (!mdwc->in_host_mode && !mdwc->in_device_mode) {

		dbg_event(0xFF, "lpm_state", atomic_read(&dwc->in_lpm));



	dbg_event(0xFF, "USB_lpm_state", atomic_read(&dwc->in_lpm));

		/*

		 * stop host mode functionality performs autosuspend with mdwc

		 * device, and it may take sometime to call PM runtime suspend.

		 * Hence call pm_runtime_suspend() API to invoke PM runtime

	 * suspend immediately to put USB controller and PHYs into suspend.

		 * suspend immediately to put USB controller and PHYs into

		 * suspend.

		 */

		ret = pm_runtime_suspend(mdwc->dev);

		dbg_event(0xFF, "pm_runtime_sus", ret);



		/*

		 * If mdwc device is already suspended, pm_runtime_suspend() API

		 * returns 1, which is not error. Overwrite with zero if it is.

		 */

		if (ret > 0)

			ret = 0;

	dbg_event(0xFF, "pm_runtime_sus", ret);

	}



	dwc->maximum_speed = usb_speed;

	mdwc->otg_state = OTG_STATE_B_IDLE;

	schedule_delayed_work(&mdwc->sm_work, 0);

	dbg_event(0xFF, "complete_host_change", dwc->maximum_speed);

err:

	return ret;

}