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From:   Wesley Cheng <quic_wcheng@quicinc.com>
To:     <balbi@kernel.org>, <gregkh@linuxfoundation.org>
CC:     <linux-kernel@vger.kernel.org>, <linux-usb@vger.kernel.org>,
        <Thinh.Nguyen@synopsys.com>, <quic_jackp@quicinc.com>,
        Wesley Cheng <quic_wcheng@quicinc.com>
Subject: [PATCH 1/5] usb: dwc3: Do not service EP0 and conndone events if soft disconnected
Date:   Fri, 8 Jul 2022 11:50:03 -0700
Message-ID: <20220708185007.21743-2-quic_wcheng@quicinc.com>
In-Reply-To: <20220708185007.21743-1-quic_wcheng@quicinc.com>
References: <20220708185007.21743-1-quic_wcheng@quicinc.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

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.

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 a944c7a6c83a..298e842c384c 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -3877,6 +3877,9 @@ 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;