2022-08-25 07:27:57

by Pawel Laszczak

Subject: [PATCH] usb: cdns3: fix incorrect handling TRB_SMM flag for ISOC transfer

The TRB_SMM flag indicates that DMA has completed the TD service with
this TRB. Usually it’s a last TRB in TD. In case of ISOC transfer for
bInterval > 1 each ISOC transfer contains more than one TD associated
with usb request (one TD per ITP). In such case the TRB_SMM flag will
be set in every TD and driver will recognize the end of transfer after
processing the first TD with TRB_SMM. In result driver stops updating
request->actual and returns incorrect actual length.
To fix this issue driver additionally must check TRB_CHAIN which is not
used for isochronous transfers.

Fixes: 249f0a25e8be ("usb: cdns3: gadget: handle sg list use case at completion correctly")
cc: <[email protected]>
Signed-off-by: Pawel Laszczak <[email protected]>
---
drivers/usb/cdns3/cdns3-gadget.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
index fa8263951e63..a6618a922c61 100644
--- a/drivers/usb/cdns3/cdns3-gadget.c
+++ b/drivers/usb/cdns3/cdns3-gadget.c
@@ -1529,7 +1529,8 @@ static void cdns3_transfer_completed(struct cdns3_device *priv_dev,
TRB_LEN(le32_to_cpu(trb->length));

if (priv_req->num_of_trb > 1 &&
- le32_to_cpu(trb->control) & TRB_SMM)
+ le32_to_cpu(trb->control) & TRB_SMM &&
+ le32_to_cpu(trb->control) & TRB_CHAIN)
transfer_end = true;

cdns3_ep_inc_deq(priv_ep);
--
2.25.1

2022-08-29 02:12:31

by Peter Chen

Subject: Re: [PATCH] usb: cdns3: fix incorrect handling TRB_SMM flag for ISOC transfer

On 22-08-25 08:22:07, Pawel Laszczak wrote:
> The TRB_SMM flag indicates that DMA has completed the TD service with
> this TRB. Usually it’s a last TRB in TD. In case of ISOC transfer for
> bInterval > 1 each ISOC transfer contains more than one TD associated
> with usb request (one TD per ITP). In such case the TRB_SMM flag will
> be set in every TD and driver will recognize the end of transfer after
> processing the first TD with TRB_SMM. In result driver stops updating
> request->actual and returns incorrect actual length.
> To fix this issue driver additionally must check TRB_CHAIN which is not
> used for isochronous transfers.
>
> Fixes: 249f0a25e8be ("usb: cdns3: gadget: handle sg list use case at completion correctly")
> cc: <[email protected]>
> Signed-off-by: Pawel Laszczak <[email protected]>

Acked-by: Peter Chen <[email protected]>

> ---
> drivers/usb/cdns3/cdns3-gadget.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
> index fa8263951e63..a6618a922c61 100644
> --- a/drivers/usb/cdns3/cdns3-gadget.c
> +++ b/drivers/usb/cdns3/cdns3-gadget.c
> @@ -1529,7 +1529,8 @@ static void cdns3_transfer_completed(struct cdns3_device *priv_dev,
> TRB_LEN(le32_to_cpu(trb->length));
>
> if (priv_req->num_of_trb > 1 &&
> - le32_to_cpu(trb->control) & TRB_SMM)
> + le32_to_cpu(trb->control) & TRB_SMM &&
> + le32_to_cpu(trb->control) & TRB_CHAIN)
> transfer_end = true;
>
> cdns3_ep_inc_deq(priv_ep);
> --
> 2.25.1
>

--

Thanks,
Peter Chen