diff mbox series

[5.4,070/168] usb: cdns3: gadget: toggle cycle bit before reset endpoint

Message ID 20200310123642.341409857@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH March 10, 2020, 12:38 p.m. UTC 
From: Peter Chen <peter.chen@nxp.com>

commit 4bf2dd65135a2d7fe202f7c10d65b51bcf645ac6 upstream.

If there are TRBs pending during reset endpoint operation, the
DMA will advance after reset operation, but it isn't expected,
since the data is not yet available (For OUT, the data is not
yet available). After the data is ready, there won't be any
interrupt since the EP_TRADDR already points to next TRB entry
and doorbell is not set.

To fix it, it toggles cycle bit before reset operation, and restores
it after reset, it could avoid unexpected DMA advance due to
cycle bit is for software during the endpoint reset operation.

Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
Signed-off-by: Peter Chen <peter.chen@nxp.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200219141455.23257-3-peter.chen@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/cdns3/gadget.c |   17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)
diff mbox series

Patch

--- a/drivers/usb/cdns3/gadget.c
+++ b/drivers/usb/cdns3/gadget.c
@@ -2152,11 +2152,21 @@  int __cdns3_gadget_ep_clear_halt(struct
 {
 	struct cdns3_device *priv_dev = priv_ep->cdns3_dev;
 	struct usb_request *request;
+	struct cdns3_request *priv_req;
+	struct cdns3_trb *trb = NULL;
 	int ret;
 	int val;
 
 	trace_cdns3_halt(priv_ep, 0, 0);
 
+	request = cdns3_next_request(&priv_ep->pending_req_list);
+	if (request) {
+		priv_req = to_cdns3_request(request);
+		trb = priv_req->trb;
+		if (trb)
+			trb->control = trb->control ^ TRB_CYCLE;
+	}
+
 	writel(EP_CMD_CSTALL | EP_CMD_EPRST, &priv_dev->regs->ep_cmd);
 
 	/* wait for EPRST cleared */
@@ -2167,10 +2177,11 @@  int __cdns3_gadget_ep_clear_halt(struct
 
 	priv_ep->flags &= ~(EP_STALLED | EP_STALL_PENDING);
 
-	request = cdns3_next_request(&priv_ep->pending_req_list);
-
-	if (request)
+	if (request) {
+		if (trb)
+			trb->control = trb->control ^ TRB_CYCLE;
 		cdns3_rearm_transfer(priv_ep, 1);
+	}
 
 	cdns3_start_all_request(priv_dev, priv_ep);
 	return ret;