commit 50c763f8c1bac0dc00f7788a75f227276c0efd54
author John Youn <johnyoun@synopsys.com> Tue May 31 17:49:56 2016 -0700
committer Felipe Balbi <felipe.balbi@linux.intel.com> Wed Jun 01 09:53:42 2016 +0300
tree 2a46613c494e2a9b2908c993181122628a2e7458
parent 27a0faafdca53bda21ed340ca8f8960696dda049

usb: dwc3: Set the ClearPendIN bit on Clear Stall EP command

As of core revision 2.60a the recommended programming model is to set
the ClearPendIN bit when issuing a Clear Stall EP command for IN
endpoints. This is to prevent an issue where some (non-compliant) hosts
may not send ACK TPs for pending IN transfers due to a mishandled error
condition. Synopsys STAR 9000614252.

Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/gadget.c

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 9a7d0bd..07248ff 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -347,6 +347,28 @@
 	return ret;
 }
 
+static int dwc3_send_clear_stall_ep_cmd(struct dwc3_ep *dep)
+{
+	struct dwc3 *dwc = dep->dwc;
+	struct dwc3_gadget_ep_cmd_params params;
+	u32 cmd = DWC3_DEPCMD_CLEARSTALL;
+
+	/*
+	 * As of core revision 2.60a the recommended programming model
+	 * is to set the ClearPendIN bit when issuing a Clear Stall EP
+	 * command for IN endpoints. This is to prevent an issue where
+	 * some (non-compliant) hosts may not send ACK TPs for pending
+	 * IN transfers due to a mishandled error condition. Synopsys
+	 * STAR 9000614252.
+	 */
+	if (dep->direction && (dwc->revision >= DWC3_REVISION_260A))
+		cmd |= DWC3_DEPCMD_CLEARPENDIN;
+
+	memset(&params, 0, sizeof(params));
+
+	return dwc3_send_gadget_ep_cmd(dwc, dep->number, cmd, &params);
+}
+
 static dma_addr_t dwc3_trb_dma_offset(struct dwc3_ep *dep,
 		struct dwc3_trb *trb)
 {
@@ -1314,8 +1336,7 @@
 		else
 			dep->flags |= DWC3_EP_STALL;
 	} else {
-		ret = dwc3_send_gadget_ep_cmd(dwc, dep->number,
-			DWC3_DEPCMD_CLEARSTALL, &params);
+		ret = dwc3_send_clear_stall_ep_cmd(dep);
 		if (ret)
 			dev_err(dwc->dev, "failed to clear STALL on %s\n",
 					dep->name);
@@ -2247,7 +2268,6 @@
 
 	for (epnum = 1; epnum < DWC3_ENDPOINTS_NUM; epnum++) {
 		struct dwc3_ep *dep;
-		struct dwc3_gadget_ep_cmd_params params;
 		int ret;
 
 		dep = dwc->eps[epnum];
@@ -2259,9 +2279,7 @@
 
 		dep->flags &= ~DWC3_EP_STALL;
 
-		memset(&params, 0, sizeof(params));
-		ret = dwc3_send_gadget_ep_cmd(dwc, dep->number,
-				DWC3_DEPCMD_CLEARSTALL, &params);
+		ret = dwc3_send_clear_stall_ep_cmd(dep);
 		WARN_ON_ONCE(ret);
 	}
 }