commit f09ddcfcb8c5 ("usb: dwc3: gadget: Prevent EP queuing while stopping
transfers") addressed an issue where the DWC3 gadget was still allowing EP
queuing to occur while the pullup disable routine was executing. This led to
a situation where the controller prepares a TRB, which will be unmapped by the
stop active transfer call.
In addition to the above, there are a few other places in the DWC3 gadget where
we need to block preparing of TRBs:
1. While the DWC3 gadget cleans up completed TRBs (during
dwc3_gadget_endpoint_trbs_complete()), DWC3 gadget giveback is utilized and
will release the dwc->lock. If a pullup disable call occurs while the
cleanup is happening, then there is a chance dwc3_gadget_ep_should_continue
will prepare a TRB, which will later on be unmapped by the stop active
transfer in the pullup disable path.
2. If we are in the CONFIGURED state and the host issues a bus RESET. In this
situation, the connected flag is still set to true while we stop active
transfers, which can lead to the same initial problem. Ideally, function
drivers would stop any pending usb requests through dwc3_reset_gadget()
using the EP disable call, but for some function drivers, this does not
occur synchronously in their disable() callback. These functions would rely
on the stop active transfers in the reset handler to issue the endxfer cmd.
Wesley Cheng (2):
usb: dwc3: gadget: Avoid continuing preparing TRBs during teardown
usb: dwc3: gadget: Ignore EP queue requests during bus reset
drivers/usb/dwc3/gadget.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
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