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Commit 0b0cc1cd authored by Felipe Balbi's avatar Felipe Balbi
Browse files

usb: dwc3: workaround: unexpected transtion U3 -> RESUME 



In DWC3 versions < 2.50a configured without
Hibernation mode enabled, there will be an
extra link status change interrupt if device
detects host-initiated U3 exit.

In that case, core will generate an unnecessary
U3 -> RESUME transition which should be ignored
by the driver.

Signed-off-by: default avatarFelipe Balbi <balbi@ti.com>
parent 7ac6a593

drivers/usb/dwc3/gadget.c

+28 −0
Original line number Diff line number Diff line
@@ -2317,6 +2317,34 @@ static void dwc3_gadget_linksts_change_interrupt(struct dwc3 *dwc, 
		unsigned int evtinfo)

{

	enum dwc3_link_state	next = evtinfo & DWC3_LINK_STATE_MASK;

	unsigned int		pwropt;



	/*

	 * WORKAROUND: DWC3 < 2.50a have an issue when configured without

	 * Hibernation mode enabled which would show up when device detects

	 * host-initiated U3 exit.

	 *

	 * In that case, device will generate a Link State Change Interrupt

	 * from U3 to RESUME which is only necessary if Hibernation is

	 * configured in.

	 *

	 * There are no functional changes due to such spurious event and we

	 * just need to ignore it.

	 *

	 * Refers to:

	 *

	 * STAR#9000570034 RTL: SS Resume event generated in non-Hibernation

	 * operational mode

	 */

	pwropt = DWC3_GHWPARAMS1_EN_PWROPT(dwc->hwparams.hwparams1);

	if ((dwc->revision < DWC3_REVISION_250A) &&

			(pwropt != DWC3_GHWPARAMS1_EN_PWROPT_HIB)) {

		if ((dwc->link_state == DWC3_LINK_STATE_U3) &&

				(next == DWC3_LINK_STATE_RESUME)) {

			dev_vdbg(dwc->dev, "ignoring transition U3 -> Resume\n");

			return;

		}

	}



	/*

	 * WORKAROUND: DWC3 Revisions <1.83a have an issue which, depending