[PATCH v3 3/3] usb: chipidea: udc: improve error recovery for ISO transfer

[Xu Yang <xu.yang_2@nxp.com>]

Impove device mode ISO transfer error tolerant by reprime the corresponding
endpoint.

The recovery steps when error occurs:
- Delete the error dTD from dQH and giveback request to user.
- Do reprime if dQH is not empty.
- Do prime when new dTD is queued if dQH is empty

Acked-by: Peter Chen <peter.chen@kernel.org>
Signed-off-by: Xu Yang <xu.yang_2@nxp.com>

---
Changes in v2:
 - modify commit message
 - keep "hwreq->req.status = tmptoken & TD_STATUS"
 - giveback status 0 to user for isoc error case
Changes in v3:
 - add Acked-by tag
---
 drivers/usb/chipidea/udc.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
index 0132bb25c9b5..18c1882cf088 100644
--- a/drivers/usb/chipidea/udc.c
+++ b/drivers/usb/chipidea/udc.c
@@ -683,6 +683,7 @@ static int _hardware_dequeue(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq)
 	unsigned remaining_length;
 	unsigned actual = hwreq->req.length;
 	struct ci_hdrc *ci = hwep->ci;
+	bool is_isoc = hwep->type == USB_ENDPOINT_XFER_ISOC;
 
 	if (hwreq->req.status != -EALREADY)
 		return -EINVAL;
@@ -696,7 +697,7 @@ static int _hardware_dequeue(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq)
 			int n = hw_ep_bit(hwep->num, hwep->dir);
 
 			if (ci->rev == CI_REVISION_24 ||
-			    ci->rev == CI_REVISION_22)
+			    ci->rev == CI_REVISION_22 || is_isoc)
 				if (!hw_read(ci, OP_ENDPTSTAT, BIT(n)))
 					reprime_dtd(ci, hwep, node);
 			hwreq->req.status = -EALREADY;
@@ -715,11 +716,15 @@ static int _hardware_dequeue(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq)
 			hwreq->req.status = -EPROTO;
 			break;
 		} else if ((TD_STATUS_TR_ERR & hwreq->req.status)) {
-			hwreq->req.status = -EILSEQ;
-			break;
+			if (is_isoc) {
+				hwreq->req.status = 0;
+			} else {
+				hwreq->req.status = -EILSEQ;
+				break;
+			}
 		}
 
-		if (remaining_length) {
+		if (remaining_length && !is_isoc) {
 			if (hwep->dir == TX) {
 				hwreq->req.status = -EPROTO;
 				break;
-- 
2.34.1