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usb: chipidea: udc: improve dTD link logic

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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>
Acked-by: Peter Chen <peter.chen@kernel.org>
Link: https://lore.kernel.org/r/20240926022906.473319-2-xu.yang_2@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Xu Yang 2024-09-26 10:29:05 +08:00 committed by Greg Kroah-Hartman
parent 548f48b66c
commit b8c7f7e188
1 changed files with 8 additions and 1 deletions
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9
drivers/usb/chipidea/udc.c
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@ -753,10 +753,17 @@ 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 */