Commit e7898836 authored Mar 11, 2020 by Sriharsha Allenki

usb: dwc3: gadget: Issue soft reset as part of composition switch



As part of composition switch, the device initiates
disconnect from the host by clearing the run/stop
bit of DCTL and initiates a connect by setting the run/stop bit.
But during this entire scenario the core is not reset
and there is a possibility of core caching the SETUP packets
from the previous session and giving this to the driver once the
run/stop bit is set leading to unintnented SETUP packets further
leading to stall on endpoint 0. This caused the endpoint 0 to
go into a bad state leading to enumeration failures.

Also, the databook clearly mentions that the soft reset has
to be issued before setting the run/stop bit to initialize a
conenct after a disconnect.
So, issue soft reset as part of composition switch to fix this
issue.

Change-Id: Id93bef710e7cdb67a6820cb4c9defecc5ad2a34e
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>

parent ef302ddf

drivers/usb/dwc3/gadget.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -2102,6 +2102,12 @@ static int dwc3_device_core_soft_reset(struct dwc3 *dwc)
		/* phy sync delay as per data book */
		msleep(50);

		/*
		* Soft reset clears the block on the doorbell,
		* set it back to prevent unwanted writes to the doorbell.
		*/
		dwc3_notify_event(dwc, DWC3_CONTROLLER_NOTIFY_CLEAR_DB, 0);

		return 0;
		}

		@@ -2265,6 +2271,9 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
		/* prevent pending bh to run later */
		flush_work(&dwc->bh_work);

		if (is_on)
		dwc3_device_core_soft_reset(dwc);

		spin_lock_irqsave(&dwc->lock, flags);
		if (dwc->ep0state != EP0_SETUP_PHASE)
		dbg_event(0xFF, "EP0 is not in SETUP phase\n", 0);