Re: [PATCH 6/6] usb: chipidea: udc: Add xilinx revision support

Peter Chen
2021-10-07T05:02:18Z

On 21-08-24 22:46:18, Manish Narani wrote:
> From: Piyush Mehta <piyush.mehta@xilinx.com>
>
> 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@xilinx.com>
> Signed-off-by: Manish Narani <manish.narani@xilinx.com>
> ---
> 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 8834ca6..b440205 100644
> --- a/drivers/usb/chipidea/udc.c
> +++ b/drivers/usb/chipidea/udc.c
> @@ -680,7 +680,8 @@ 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)

Add indent for it, otherwise:

Acked-by: Peter Chen <peter.chen@kernel.org>

> if (!hw_read(ci, OP_ENDPTSTAT, BIT(n)))
> reprime_dtd(ci, hwep, node);
> hwreq->req.status = -EALREADY;
> --
> 2.1.1
>

--

Thanks,
Peter Chen