Linux-USB Archive on lore.kernel.org
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From: Peter Chen <peter.chen@nxp.com>
To: balbi@kernel.org
Cc: linux-usb@vger.kernel.org, linux-imx@nxp.com, pawell@cadence.com,
	rogerq@ti.com, gregkh@linuxfoundation.org, jun.li@nxp.com,
	Peter Chen <peter.chen@nxp.com>
Subject: [PATCH 2/2] usb: cdns3: gadget: toggle cycle bit before reset endpoint
Date: Fri, 14 Feb 2020 15:14:14 +0800
Message-ID: <20200214071414.7256-3-peter.chen@nxp.com> (raw)
In-Reply-To: <20200214071414.7256-1-peter.chen@nxp.com>

If there are TRBs pending during clear stall and reset endpoint, the
DMA will advance after reset operation, but it doesn't be expected,
since the data has still not be ready (For OUT, the data has still
not received). After the data is ready, there isn't any interrupt
since the EP_TRADDR has already points to next TRB entry.

To fix it, it toggles cyclt bit before reset operation, and restore
it after reset, it could keep DMA stopping.

Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
Signed-off-by: Peter Chen <peter.chen@nxp.com>
---
 drivers/usb/cdns3/gadget.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
index 1d8a2af35bb0..7b6bb96b91d1 100644
--- a/drivers/usb/cdns3/gadget.c
+++ b/drivers/usb/cdns3/gadget.c
@@ -2595,11 +2595,21 @@ int __cdns3_gadget_ep_clear_halt(struct cdns3_endpoint *priv_ep)
 {
 	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 ^ 1;
+	}
+
 	writel(EP_CMD_CSTALL | EP_CMD_EPRST, &priv_dev->regs->ep_cmd);
 
 	/* wait for EPRST cleared */
@@ -2610,10 +2620,11 @@ int __cdns3_gadget_ep_clear_halt(struct cdns3_endpoint *priv_ep)
 
 	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 ^ 1;
 		cdns3_rearm_transfer(priv_ep, 1);
+	}
 
 	cdns3_start_all_request(priv_dev, priv_ep);
 	return ret;
-- 
2.17.1


  parent reply index

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-14  7:14 [PATCH 0/2] usb: cdns3: two fixes for gadget Peter Chen
2020-02-14  7:14 ` [PATCH 1/2] usb: cdns3: gadget: link trb should point to next request Peter Chen
2020-02-14  7:14 ` Peter Chen [this message]
2020-02-14  7:41   ` [PATCH 2/2] usb: cdns3: gadget: toggle cycle bit before reset endpoint Pawel Laszczak
2020-02-16 13:42     ` Peter Chen
2020-02-14  8:48   ` Roger Quadros
2020-02-16 13:56     ` Peter Chen

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