usb: dwc3: Do not service EP0 and conndone events if soft disconnected
authorWesley Cheng <quic_wcheng@quicinc.com>
Wed, 17 Aug 2022 18:23:51 +0000 (11:23 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 31 Aug 2022 07:07:53 +0000 (09:07 +0200)
commit359d5a85a758906087801d7b3d3536a984211dec
treecdfdba0ed7c169e36c2a1b542ffb7ef6a6978e1d
parentc69400b09e471a3f1167adead55a808f0da6534a
usb: dwc3: Do not service EP0 and conndone events if soft disconnected

There are some operations that need to be ignored if there is a soft
disconnect in progress.  This is to avoid having a pending EP0 transfer in
progress while attempting to stop active transfers and halting the
controller.

There were several instances seen where a soft disconnect was able to occur
during early link negotiation, i.e. bus reset/conndone, which leads to the
conndone handler re-configuring EPs while attempting to halt the
controller, as DEP flags are cleared as part of the soft disconnect path.

ep0out: cmd 'Start New Configuration'
ep0out: cmd 'Set Endpoint Transfer Resource'
ep0in: cmd 'Set Endpoint Transfer Resource'
ep1out: cmd 'Set Endpoint Transfer Resource'
...
event (00030601): Suspend [U3]
event (00000101): Reset [U0]
ep0out: req ffffff87e5c9e100 length 0/0 zsI ==> 0
event (00000201): Connection Done [U0]
ep0out: cmd 'Start New Configuration'
ep0out: cmd 'Set Endpoint Transfer Resource'

In addition, if a soft disconnect occurs, EP0 events are still allowed to
process, however, it will stall/restart during the SETUP phase.  The
host is still able to query for the DATA phase, leading to a
xfernotready(DATA) event.  Since none of the SETUP transfer parameters are
populated, the xfernotready is treated as a "wrong direction" error,
leading to a duplicate stall/restart routine.

Add the proper softconnect/connected checks in sequences that are
potentially involved during soft disconnect processing.

Reviewed-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Link: https://lore.kernel.org/r/20220817182359.13550-2-quic_wcheng@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/dwc3/ep0.c
drivers/usb/dwc3/gadget.c