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From:   Wesley Cheng <quic_wcheng@quicinc.com>
To:     <balbi@kernel.org>, <gregkh@linuxfoundation.org>,
        <Thinh.Nguyen@synopsys.com>
CC:     <linux-kernel@vger.kernel.org>, <linux-usb@vger.kernel.org>,
        <quic_jackp@quicinc.com>, Wesley Cheng <quic_wcheng@quicinc.com>
Subject: [PATCH v6 1/5] usb: dwc3: Avoid unmapping USB requests if endxfer is not complete
Date:   Thu, 1 Sep 2022 11:43:10 -0700
Message-ID: <20220901184314.30481-2-quic_wcheng@quicinc.com>
In-Reply-To: <20220901184314.30481-1-quic_wcheng@quicinc.com>
References: <20220901184314.30481-1-quic_wcheng@quicinc.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

If DWC3_EP_DELAYED_STOP is set during stop active transfers, then do not
continue attempting to unmap request buffers during dwc3_remove_requests().
This can lead to SMMU faults, as the controller has not stopped the
processing of the TRB.  Defer this sequence to the EP0 out start, which
ensures that there are no pending SETUP transactions before issuing the
endxfer.

Reviewed-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
---
 drivers/usb/dwc3/core.h   | 3 +++
 drivers/usb/dwc3/ep0.c    | 5 ++++-
 drivers/usb/dwc3/gadget.c | 6 +++++-
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 4fe4287dc934..7d5d2507244b 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1560,6 +1560,7 @@ int dwc3_send_gadget_ep_cmd(struct dwc3_ep *dep, unsigned int cmd,
 int dwc3_send_gadget_generic_command(struct dwc3 *dwc, unsigned int cmd,
 		u32 param);
 void dwc3_gadget_clear_tx_fifos(struct dwc3 *dwc);
+void dwc3_remove_requests(struct dwc3 *dwc, struct dwc3_ep *dep, int status);
 #else
 static inline int dwc3_gadget_init(struct dwc3 *dwc)
 { return 0; }
@@ -1581,6 +1582,8 @@ static inline int dwc3_send_gadget_generic_command(struct dwc3 *dwc,
 { return 0; }
 static inline void dwc3_gadget_clear_tx_fifos(struct dwc3 *dwc)
 { }
+static inline void dwc3_remove_requests(struct dwc3 *dwc, struct dwc3_ep *dep)
+{ }
 #endif
 
 #if IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE)
diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index 33cee0089609..61de693461da 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -293,7 +293,10 @@ void dwc3_ep0_out_start(struct dwc3 *dwc)
 			continue;
 
 		dwc3_ep->flags &= ~DWC3_EP_DELAY_STOP;
-		dwc3_stop_active_transfer(dwc3_ep, true, true);
+		if (dwc->connected)
+			dwc3_stop_active_transfer(dwc3_ep, true, true);
+		else
+			dwc3_remove_requests(dwc, dwc3_ep, -ESHUTDOWN);
 	}
 }
 
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index d6c0cb79ace3..6f2491fc109e 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -965,12 +965,16 @@ static int __dwc3_gadget_ep_enable(struct dwc3_ep *dep, unsigned int action)
 	return 0;
 }
 
-static void dwc3_remove_requests(struct dwc3 *dwc, struct dwc3_ep *dep, int status)
+void dwc3_remove_requests(struct dwc3 *dwc, struct dwc3_ep *dep, int status)
 {
 	struct dwc3_request		*req;
 
 	dwc3_stop_active_transfer(dep, true, false);
 
+	/* If endxfer is delayed, avoid unmapping requests */
+	if (dep->flags & DWC3_EP_DELAY_STOP)
+		return;
+
 	/* - giveback all requests to gadget driver */
 	while (!list_empty(&dep->started_list)) {
 		req = next_request(&dep->started_list);