diff mbox series

usb: cdnsp: fix issue with ZLP - added TD_SIZE = 1

Message ID 1666159637-161135-1-git-send-email-pawell@cadence.com
State New
Headers
Series usb: cdnsp: fix issue with ZLP - added TD_SIZE = 1 |

Commit Message

Pawel Laszczak Oct. 19, 2022, 6:07 a.m. UTC 
  Patch modifies the TD_SIZE in TRB before ZLP TRB.
The TD_SIZE in TRB before ZLP TRB must be set to 1 to force
processing ZLP TRB by controller.

Cc: <stable@vger.kernel.org>
Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
---
 drivers/usb/cdns3/cdnsp-ring.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

Comments

Peter Chen Oct. 20, 2022, 1:20 p.m. UTC | #1 
On 22-10-19 02:07:17, Pawel Laszczak wrote:
> Patch modifies the TD_SIZE in TRB before ZLP TRB.
> The TD_SIZE in TRB before ZLP TRB must be set to 1 to force
> processing ZLP TRB by controller.
> 
> Cc: <stable@vger.kernel.org>
> Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
> Signed-off-by: Pawel Laszczak <pawell@cadence.com>
> ---
>  drivers/usb/cdns3/cdnsp-ring.c | 15 ++++++++-------
>  1 file changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/usb/cdns3/cdnsp-ring.c b/drivers/usb/cdns3/cdnsp-ring.c
> index 794e413800ae..4809d0e894bb 100644
> --- a/drivers/usb/cdns3/cdnsp-ring.c
> +++ b/drivers/usb/cdns3/cdnsp-ring.c
> @@ -1765,18 +1765,19 @@ static u32 cdnsp_td_remainder(struct cdnsp_device *pdev,
>  			      struct cdnsp_request *preq,
>  			      bool more_trbs_coming)
>  {
> -	u32 maxp, total_packet_count;
> -
> -	/* One TRB with a zero-length data packet. */
> -	if (!more_trbs_coming || (transferred == 0 && trb_buff_len == 0) ||
> -	    trb_buff_len == td_total_len)
> -		return 0;
> +	u32 maxp, total_packet_count, remainder;
>  
>  	maxp = usb_endpoint_maxp(preq->pep->endpoint.desc);
>  	total_packet_count = DIV_ROUND_UP(td_total_len, maxp);
>  
>  	/* Queuing functions don't count the current TRB into transferred. */
> -	return (total_packet_count - ((transferred + trb_buff_len) / maxp));
> +	remainder = (total_packet_count - ((transferred + trb_buff_len) / maxp));
> +
> +	/* Before ZLP driver needs set TD_SIZE=1. */
> +	if (!remainder && more_trbs_coming)
> +		remainder = 1;

Without ZLP, TD_SIZE = 0 for the last TRB.
With ZLP, TD_SIZE = 1 for current TRB, and TD_SIZE = 0 for the next TRB
(the last zero-length packet) right?

Peter

> +
> +	return remainder;
>  }
>  
>  static int cdnsp_align_td(struct cdnsp_device *pdev,
> -- 
> 2.25.1
>
Pawel Laszczak Oct. 21, 2022, 5:03 a.m. UTC | #2 
>
>
>On 22-10-19 02:07:17, Pawel Laszczak wrote:
>> Patch modifies the TD_SIZE in TRB before ZLP TRB.
>> The TD_SIZE in TRB before ZLP TRB must be set to 1 to force processing
>> ZLP TRB by controller.
>>
>> Cc: <stable@vger.kernel.org>
>> Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence
>> USBSSP DRD Driver")
>> Signed-off-by: Pawel Laszczak <pawell@cadence.com>
>> ---
>>  drivers/usb/cdns3/cdnsp-ring.c | 15 ++++++++-------
>>  1 file changed, 8 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/usb/cdns3/cdnsp-ring.c
>> b/drivers/usb/cdns3/cdnsp-ring.c index 794e413800ae..4809d0e894bb
>> 100644
>> --- a/drivers/usb/cdns3/cdnsp-ring.c
>> +++ b/drivers/usb/cdns3/cdnsp-ring.c
>> @@ -1765,18 +1765,19 @@ static u32 cdnsp_td_remainder(struct
>cdnsp_device *pdev,
>>  			      struct cdnsp_request *preq,
>>  			      bool more_trbs_coming)
>>  {
>> -	u32 maxp, total_packet_count;
>> -
>> -	/* One TRB with a zero-length data packet. */
>> -	if (!more_trbs_coming || (transferred == 0 && trb_buff_len == 0) ||
>> -	    trb_buff_len == td_total_len)
>> -		return 0;
>> +	u32 maxp, total_packet_count, remainder;
>>
>>  	maxp = usb_endpoint_maxp(preq->pep->endpoint.desc);
>>  	total_packet_count = DIV_ROUND_UP(td_total_len, maxp);
>>
>>  	/* Queuing functions don't count the current TRB into transferred. */
>> -	return (total_packet_count - ((transferred + trb_buff_len) / maxp));
>> +	remainder = (total_packet_count - ((transferred + trb_buff_len) /
>> +maxp));
>> +
>> +	/* Before ZLP driver needs set TD_SIZE=1. */
>> +	if (!remainder && more_trbs_coming)
>> +		remainder = 1;
>
>Without ZLP, TD_SIZE = 0 for the last TRB.
>With ZLP, TD_SIZE = 1 for current TRB, and TD_SIZE = 0 for the next TRB (the
>last zero-length packet) right?

Yes, you have right.

Pawel

>Peter
>
>> +
>> +	return remainder;
>>  }
>>
>>  static int cdnsp_align_td(struct cdnsp_device *pdev,
>> --
>> 2.25.1
>>
>
>--
>
>Thanks,
>Peter Chen

Regards,
Pawel Laszczak
Peter Chen Oct. 22, 2022, 1:43 p.m. UTC | #3 
On 22-10-21 05:03:25, Pawel Laszczak wrote:
> >
> >
> >On 22-10-19 02:07:17, Pawel Laszczak wrote:
> >> Patch modifies the TD_SIZE in TRB before ZLP TRB.
> >> The TD_SIZE in TRB before ZLP TRB must be set to 1 to force processing
> >> ZLP TRB by controller.
> >>
> >> Cc: <stable@vger.kernel.org>
> >> Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence
> >> USBSSP DRD Driver")
> >> Signed-off-by: Pawel Laszczak <pawell@cadence.com>
> >> ---
> >>  drivers/usb/cdns3/cdnsp-ring.c | 15 ++++++++-------
> >>  1 file changed, 8 insertions(+), 7 deletions(-)
> >>
> >> diff --git a/drivers/usb/cdns3/cdnsp-ring.c
> >> b/drivers/usb/cdns3/cdnsp-ring.c index 794e413800ae..4809d0e894bb
> >> 100644
> >> --- a/drivers/usb/cdns3/cdnsp-ring.c
> >> +++ b/drivers/usb/cdns3/cdnsp-ring.c
> >> @@ -1765,18 +1765,19 @@ static u32 cdnsp_td_remainder(struct
> >cdnsp_device *pdev,
> >>  			      struct cdnsp_request *preq,
> >>  			      bool more_trbs_coming)
> >>  {
> >> -	u32 maxp, total_packet_count;
> >> -
> >> -	/* One TRB with a zero-length data packet. */
> >> -	if (!more_trbs_coming || (transferred == 0 && trb_buff_len == 0) ||
> >> -	    trb_buff_len == td_total_len)
> >> -		return 0;
> >> +	u32 maxp, total_packet_count, remainder;
> >>
> >>  	maxp = usb_endpoint_maxp(preq->pep->endpoint.desc);
> >>  	total_packet_count = DIV_ROUND_UP(td_total_len, maxp);
> >>
> >>  	/* Queuing functions don't count the current TRB into transferred. */
> >> -	return (total_packet_count - ((transferred + trb_buff_len) / maxp));
> >> +	remainder = (total_packet_count - ((transferred + trb_buff_len) /
> >> +maxp));
> >> +
> >> +	/* Before ZLP driver needs set TD_SIZE=1. */
> >> +	if (!remainder && more_trbs_coming)
> >> +		remainder = 1;
> >
> >Without ZLP, TD_SIZE = 0 for the last TRB.
> >With ZLP, TD_SIZE = 1 for current TRB, and TD_SIZE = 0 for the next TRB (the
> >last zero-length packet) right?
> 
> Yes, you have right.
> 

Pawel, With your changes, the return value is 1 for function
cdnsp_queue_ctrl_tx. Without your changes, it is 0, something wrong?
Pawel Laszczak Oct. 24, 2022, 2:10 p.m. UTC | #4 
>> >
>> >On 22-10-19 02:07:17, Pawel Laszczak wrote:
>> >> Patch modifies the TD_SIZE in TRB before ZLP TRB.
>> >> The TD_SIZE in TRB before ZLP TRB must be set to 1 to force
>> >> processing ZLP TRB by controller.
>> >>
>> >> Cc: <stable@vger.kernel.org>
>> >> Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence
>> >> USBSSP DRD Driver")
>> >> Signed-off-by: Pawel Laszczak <pawell@cadence.com>
>> >> ---
>> >>  drivers/usb/cdns3/cdnsp-ring.c | 15 ++++++++-------
>> >>  1 file changed, 8 insertions(+), 7 deletions(-)
>> >>
>> >> diff --git a/drivers/usb/cdns3/cdnsp-ring.c
>> >> b/drivers/usb/cdns3/cdnsp-ring.c index 794e413800ae..4809d0e894bb
>> >> 100644
>> >> --- a/drivers/usb/cdns3/cdnsp-ring.c
>> >> +++ b/drivers/usb/cdns3/cdnsp-ring.c
>> >> @@ -1765,18 +1765,19 @@ static u32 cdnsp_td_remainder(struct
>> >cdnsp_device *pdev,
>> >>  			      struct cdnsp_request *preq,
>> >>  			      bool more_trbs_coming)
>> >>  {
>> >> -	u32 maxp, total_packet_count;
>> >> -
>> >> -	/* One TRB with a zero-length data packet. */
>> >> -	if (!more_trbs_coming || (transferred == 0 && trb_buff_len == 0) ||
>> >> -	    trb_buff_len == td_total_len)
>> >> -		return 0;
>> >> +	u32 maxp, total_packet_count, remainder;
>> >>
>> >>  	maxp = usb_endpoint_maxp(preq->pep->endpoint.desc);
>> >>  	total_packet_count = DIV_ROUND_UP(td_total_len, maxp);
>> >>
>> >>  	/* Queuing functions don't count the current TRB into transferred. */
>> >> -	return (total_packet_count - ((transferred + trb_buff_len) / maxp));
>> >> +	remainder = (total_packet_count - ((transferred + trb_buff_len) /
>> >> +maxp));
>> >> +
>> >> +	/* Before ZLP driver needs set TD_SIZE=1. */
>> >> +	if (!remainder && more_trbs_coming)
>> >> +		remainder = 1;
>> >
>> >Without ZLP, TD_SIZE = 0 for the last TRB.
>> >With ZLP, TD_SIZE = 1 for current TRB, and TD_SIZE = 0 for the next
>> >TRB (the last zero-length packet) right?
>>
>> Yes, you have right.
>>
>
>Pawel, With your changes, the return value is 1 for function
>cdnsp_queue_ctrl_tx. Without your changes, it is 0, something wrong?
>
Yes you have right. 
It does not cause a problem, but it's not according with controller specification. 

I posted the fixed version of this patch.

Thanks,
Pawel
diff mbox series

Patch

diff --git a/drivers/usb/cdns3/cdnsp-ring.c b/drivers/usb/cdns3/cdnsp-ring.c
index 794e413800ae..4809d0e894bb 100644
--- a/drivers/usb/cdns3/cdnsp-ring.c
+++ b/drivers/usb/cdns3/cdnsp-ring.c
@@ -1765,18 +1765,19 @@  static u32 cdnsp_td_remainder(struct cdnsp_device *pdev,
 			      struct cdnsp_request *preq,
 			      bool more_trbs_coming)
 {
-	u32 maxp, total_packet_count;
-
-	/* One TRB with a zero-length data packet. */
-	if (!more_trbs_coming || (transferred == 0 && trb_buff_len == 0) ||
-	    trb_buff_len == td_total_len)
-		return 0;
+	u32 maxp, total_packet_count, remainder;
 
 	maxp = usb_endpoint_maxp(preq->pep->endpoint.desc);
 	total_packet_count = DIV_ROUND_UP(td_total_len, maxp);
 
 	/* Queuing functions don't count the current TRB into transferred. */
-	return (total_packet_count - ((transferred + trb_buff_len) / maxp));
+	remainder = (total_packet_count - ((transferred + trb_buff_len) / maxp));
+
+	/* Before ZLP driver needs set TD_SIZE=1. */
+	if (!remainder && more_trbs_coming)
+		remainder = 1;
+
+	return remainder;
 }
 
 static int cdnsp_align_td(struct cdnsp_device *pdev,