diff mbox series

[v3,2/3] usb: chipidea: udc: improve dTD link logic

Message ID 20240926022906.473319-2-xu.yang_2@nxp.com
State New
Headers show
Series None | expand

Commit Message

Xu Yang Sept. 26, 2024, 2:29 a.m. UTC 
Currently, ATDTW semaphore is used to safety link new dTD to dQH. But this
code has a bug when the endpoint is already in error before polling ATDTW
or just met error during polling ATDTW. In that cases, ATDTW will never
turn to 1 and the cpu will busy loop there.

When the endpoint met error, ENDPTSTAT will be cleared by HW. Therefore,
ENDPTSTAT should also be considered during this process. In case of
endpoint error, the current dTD should not be pushed to the head of dQH
since some dTDs may be still not executed. Therefore, the link logic is
also improved accordingly.

Signed-off-by: Xu Yang <xu.yang_2@nxp.com>

---
Changes in v2:
 - modify comments
 - fix kernel test robot build warning by using cpu_to_le32
 - add fix tag and cc stable
Changes in v3:
 - remove fixes tag and stable maillist
---
 drivers/usb/chipidea/udc.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
index b9ccf62e0a50..0132bb25c9b5 100644
--- a/drivers/usb/chipidea/udc.c
+++ b/drivers/usb/chipidea/udc.c
@@ -612,10 +612,17 @@  static int _hardware_enqueue(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq)
 		do {
 			hw_write(ci, OP_USBCMD, USBCMD_ATDTW, USBCMD_ATDTW);
 			tmp_stat = hw_read(ci, OP_ENDPTSTAT, BIT(n));
-		} while (!hw_read(ci, OP_USBCMD, USBCMD_ATDTW));
+		} while (!hw_read(ci, OP_USBCMD, USBCMD_ATDTW) && tmp_stat);
 		hw_write(ci, OP_USBCMD, USBCMD_ATDTW, 0);
 		if (tmp_stat)
 			goto done;
+
+		/* OP_ENDPTSTAT will be clear by HW when the endpoint met
+		 * err. This dTD don't push to dQH if current dTD point is
+		 * not the last one in previous request.
+		 */
+		if (hwep->qh.ptr->curr != cpu_to_le32(prevlastnode->dma))
+			goto done;
 	}
 
 	/*  QH configuration */