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 <piyush.mehta@amd.com>
Acked-by: Peter Chen <peter.chen@kernel.org>
Link: https://lore.kernel.org/r/20231102070603.777313-1-piyush.mehta@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
index 0b7bd3c643c3aa4d40fcb5612ec1ea3595f025ea..2d7f616270c17ba8d488459d7a84c62d18b083f8 100644 (file)
--- 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;