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Code Issues Releases Wiki Activity

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>
This commit is contained in:
Piyush Mehta 2023-11-02 12:36:03 +05:30 committed by Greg Kroah-Hartman
parent 6437760acc
commit a776452deb
1 changed files with 2 additions and 1 deletions
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3
drivers/usb/chipidea/udc.c
View File

@ -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;