[PATCH v2 1/5] usb: dwc3: Do not service EP0 and conndone events if soft disconnected

Wesley Cheng
2022-07-13T00:36:01Z

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.

Fixes: 861c010a2ee1 ("usb: dwc3: gadget: Refactor pullup()")
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
---
drivers/usb/dwc3/ep0.c | 6 ++++--
drivers/usb/dwc3/gadget.c | 3 +++
2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index 2a510e84eef4..506ef717fdc0 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -197,7 +197,7 @@ int dwc3_gadget_ep0_queue(struct usb_ep *ep, struct usb_request *request,
int ret;

spin_lock_irqsave(&dwc->lock, flags);
- if (!dep->endpoint.desc || !dwc->pullups_connected) {
+ if (!dep->endpoint.desc || !dwc->pullups_connected || !dwc->connected) {
dev_err(dwc->dev, "%s: can't queue to disabled endpoint\n",
dep->name);
ret = -ESHUTDOWN;
@@ -813,7 +813,7 @@ static void dwc3_ep0_inspect_setup(struct dwc3 *dwc,
int ret = -EINVAL;
u32 len;

- if (!dwc->gadget_driver || !dwc->connected)
+ if (!dwc->gadget_driver || !dwc->softconnect || !dwc->connected)
goto out;

trace_dwc3_ctrl_req(ctrl);
@@ -1116,6 +1116,8 @@ static void dwc3_ep0_xfernotready(struct dwc3 *dwc,
{
switch (event->status) {
case DEPEVT_STATUS_CONTROL_DATA:
+ if (!dwc->softconnect || !dwc->connected)
+ return;
/*
* We already have a DATA transfer in the controller's cache,
* if we receive a XferNotReady(DATA) we will ignore it, unless
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 4366c45c28cf..d1d7a5e5bd7c 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -3865,6 +3865,9 @@ static void dwc3_gadget_conndone_interrupt(struct dwc3 *dwc)
u8 lanes = 1;
u8 speed;

+ if (!dwc->softconnect)
+ return;
+
reg = dwc3_readl(dwc->regs, DWC3_DSTS);
speed = reg & DWC3_DSTS_CONNECTSPD;
dwc->speed = speed;