From a776452debdcad6d6e6f8f89fb26496038c86074 Mon Sep 17 00:00:00 2001 From: Piyush Mehta Date: Thu, 2 Nov 2023 12:36:03 +0530 Subject: usb: chipidea: udc: Add revision check of 2.20[CI_REVISION_22] Issue: Adding a dTD to a Primed Endpoint May Not Get Recognized with revision 2.20a. There is an issue with the add dTD tripwire semaphore (ATDTW bit in USBCMD register) that can cause the controller to ignore a dTD that is added to a primed endpoint. When this happens, the software can read the tripwire bit and the status bit at '1' even though the endpoint is unprimed. This issue observed with the Windows host machine. Workaround: The software must implement a periodic cycle, and check for each dTD pending on execution (Active = 1), if the endpoint is primed. It can do this by reading the corresponding bits in the ENDPTPRIME and ENDPTSTAT registers. If these bits are read at 0, the software needs to re-prime the endpoint by writing 1 to the corresponding bit in the ENDPTPRIME register. Added conditional revision check of 2.20[CI_REVISION_22] along with 2.40. Signed-off-by: Piyush Mehta Acked-by: Peter Chen Link: https://lore.kernel.org/r/20231102070603.777313-1-piyush.mehta@amd.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/chipidea/udc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c index 0b7bd3c643c3..2d7f616270c1 100644 --- a/drivers/usb/chipidea/udc.c +++ b/drivers/usb/chipidea/udc.c @@ -688,7 +688,8 @@ static int _hardware_dequeue(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq) if ((TD_STATUS_ACTIVE & tmptoken) != 0) { int n = hw_ep_bit(hwep->num, hwep->dir); - if (ci->rev == CI_REVISION_24) + if (ci->rev == CI_REVISION_24 || + ci->rev == CI_REVISION_22) if (!hw_read(ci, OP_ENDPTSTAT, BIT(n))) reprime_dtd(ci, hwep, node); hwreq->req.status = -EALREADY; -- cgit v1.2.3-58-ga151