[RFC PATCH 1/4] dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl

[RFC PATCH 1/4] dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl

[Tejas Joglekar]

This commit adds the documentation for consolidate-sgl, and
snps,consolidate-sgl property. These when set enables the quirk for
XHCI driver for consolidation of sg list into a temporary buffer when small
buffer sizes are scattered over the sg list not making up to MPS or total
transfer size within TRB cache size with Synopsys xHC.

Signed-off-by: Tejas Joglekar <joglekar@synopsys.com>
---
 Documentation/devicetree/bindings/usb/dwc3.txt     | 3 +++
 Documentation/devicetree/bindings/usb/usb-xhci.txt | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
index 9946ff9ba735..292d1f7969e4 100644
--- a/Documentation/devicetree/bindings/usb/dwc3.txt
+++ b/Documentation/devicetree/bindings/usb/dwc3.txt
@@ -104,6 +104,9 @@ Optional properties:
 			this and tx-thr-num-pkt-prd to a valid, non-zero value
 			1-16 (DWC_usb31 programming guide section 1.2.3) to
 			enable periodic ESS TX threshold.
+ - snps,consolidate-sgl: enable sg list consolidation - host mode only. Set to use
+			SG buffers of at least MPS size by consolidating smaller SG
+			buffers list into a single buffer.
 
  - <DEPRECATED> tx-fifo-resize: determines if the FIFO *has* to be reallocated.
  - snps,incr-burst-type-adjustment: Value for INCR burst type of GSBUSCFG0
diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt b/Documentation/devicetree/bindings/usb/usb-xhci.txt
index 3f378951d624..a90d853557ee 100644
--- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
+++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
@@ -43,6 +43,9 @@ Optional properties:
   - quirk-broken-port-ped: set if the controller has broken port disable mechanism
   - imod-interval-ns: default interrupt moderation interval is 5000ns
   - phys : see usb-hcd.yaml in the current directory
+  - consolidate-sgl: indicate if you need to consolidate sg list into a
+    temporary buffer when small SG buffer sizes does not make upto MPS
+    size or total transfer size across the TRB cache size.
 
 additionally the properties from usb-hcd.yaml (in the current directory) are
 supported.
-- 
2.11.0

[RESENDING RFC PATCH 0/4] Add logic to consolidate TRBs for Synopsys xHC

[Tejas Joglekar]

The Synopsys xHC has an internal TRB cache of size TRB_CACHE_SIZE for
each endpoint. The default value for TRB_CACHE_SIZE is 16 for SS and 8
for HS. The controller loads and updates the TRB cache from the
transfer ring in system memory whenever the driver issues a start
transfer or update transfer command.

For chained TRBs, the Synopsys xHC requires that the total amount of
bytes for all TRBs loaded in the TRB cache be greater than or equal to
1 MPS. Or the chain ends within the TRB cache (with a last TRB).

If this requirement is not met, the controller will not be able to
send or receive a packet and it will hang causing a driver timeout and
error.

This patch set adds logic to the XHCI driver to detect and prevent this
from happening along with the quirk to enable this logic for Synopsys
HAPS platform.

Based on Mathias's feedback on previous implementation where consolidation
was done in TRB cache, with this patch series the implementation is done
during mapping of the URB by consolidating the SG list into a temporary
buffer if the SG list buffer sizes within TRB_CACHE_SIZE is less than MPS.


Tejas Joglekar (4):
  dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl
  usb: xhci: Set quirk for XHCI_CONSOLIDATE_SG_LIST
  usb: dwc3: Add device property consolidate-sgl
  usb: xhci: Use temporary buffer to consolidate SG

Resending as 'umlaut' is not accepted by some servers in email.

 Documentation/devicetree/bindings/usb/dwc3.txt     |   3 +
 Documentation/devicetree/bindings/usb/usb-xhci.txt |   3 +
 drivers/usb/core/hcd.c                             |   8 ++
 drivers/usb/dwc3/core.c                            |   2 +
 drivers/usb/dwc3/core.h                            |   2 +
 drivers/usb/dwc3/dwc3-haps.c                       |   1 +
 drivers/usb/dwc3/host.c                            |   5 +-
 drivers/usb/host/xhci-pci.c                        |   3 +
 drivers/usb/host/xhci-plat.c                       |   3 +
 drivers/usb/host/xhci-ring.c                       |   2 +-
 drivers/usb/host/xhci.c                            | 128 +++++++++++++++++++++
 drivers/usb/host/xhci.h                            |   5 +
 12 files changed, 163 insertions(+), 2 deletions(-)

-- 
2.11.0

Re: [RESENDING RFC PATCH 0/4] Add logic to consolidate TRBs for Synopsys xHC

[Greg KH]

On Fri, Mar 27, 2020 at 02:22:23PM +0530, Tejas Joglekar wrote:
> The Synopsys xHC has an internal TRB cache of size TRB_CACHE_SIZE for
> each endpoint. The default value for TRB_CACHE_SIZE is 16 for SS and 8
> for HS. The controller loads and updates the TRB cache from the
> transfer ring in system memory whenever the driver issues a start
> transfer or update transfer command.
> 
> For chained TRBs, the Synopsys xHC requires that the total amount of
> bytes for all TRBs loaded in the TRB cache be greater than or equal to
> 1 MPS. Or the chain ends within the TRB cache (with a last TRB).
> 
> If this requirement is not met, the controller will not be able to
> send or receive a packet and it will hang causing a driver timeout and
> error.
> 
> This patch set adds logic to the XHCI driver to detect and prevent this
> from happening along with the quirk to enable this logic for Synopsys
> HAPS platform.
> 
> Based on Mathias's feedback on previous implementation where consolidation
> was done in TRB cache, with this patch series the implementation is done
> during mapping of the URB by consolidating the SG list into a temporary
> buffer if the SG list buffer sizes within TRB_CACHE_SIZE is less than MPS.
> 
> 
> Tejas Joglekar (4):
>   dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl
>   usb: xhci: Set quirk for XHCI_CONSOLIDATE_SG_LIST
>   usb: dwc3: Add device property consolidate-sgl
>   usb: xhci: Use temporary buffer to consolidate SG
> 
> Resending as 'umlaut' is not accepted by some servers in email.

Only patch 4/4 seems to have gone through :(

[RESENDING RFC PATCH 1/4] dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl

[Tejas Joglekar]

This commit adds the documentation for consolidate-sgl, and
snps,consolidate-sgl property. These when set enables the quirk for
XHCI driver for consolidation of sg list into a temporary buffer when small
buffer sizes are scattered over the sg list not making up to MPS or total
transfer size within TRB cache size with Synopsys xHC.

Signed-off-by: Tejas Joglekar <joglekar@synopsys.com>
---
 Documentation/devicetree/bindings/usb/dwc3.txt     | 3 +++
 Documentation/devicetree/bindings/usb/usb-xhci.txt | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
index 9946ff9ba735..292d1f7969e4 100644
--- a/Documentation/devicetree/bindings/usb/dwc3.txt
+++ b/Documentation/devicetree/bindings/usb/dwc3.txt
@@ -104,6 +104,9 @@ Optional properties:
 			this and tx-thr-num-pkt-prd to a valid, non-zero value
 			1-16 (DWC_usb31 programming guide section 1.2.3) to
 			enable periodic ESS TX threshold.
+ - snps,consolidate-sgl: enable sg list consolidation - host mode only. Set to use
+			SG buffers of at least MPS size by consolidating smaller SG
+			buffers list into a single buffer.
 
  - <DEPRECATED> tx-fifo-resize: determines if the FIFO *has* to be reallocated.
  - snps,incr-burst-type-adjustment: Value for INCR burst type of GSBUSCFG0
diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt b/Documentation/devicetree/bindings/usb/usb-xhci.txt
index 3f378951d624..a90d853557ee 100644
--- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
+++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
@@ -43,6 +43,9 @@ Optional properties:
   - quirk-broken-port-ped: set if the controller has broken port disable mechanism
   - imod-interval-ns: default interrupt moderation interval is 5000ns
   - phys : see usb-hcd.yaml in the current directory
+  - consolidate-sgl: indicate if you need to consolidate sg list into a
+    temporary buffer when small SG buffer sizes does not make upto MPS
+    size or total transfer size across the TRB cache size.
 
 additionally the properties from usb-hcd.yaml (in the current directory) are
 supported.
-- 
2.11.0

Re: [RESENDING RFC PATCH 0/4] Add logic to consolidate TRBs for Synopsys xHC

[Tejas Joglekar]

On 3/27/2020 2:58 PM, Greg KH wrote:
> On Fri, Mar 27, 2020 at 02:22:23PM +0530, Tejas Joglekar wrote:
>> The Synopsys xHC has an internal TRB cache of size TRB_CACHE_SIZE for
>> each endpoint. The default value for TRB_CACHE_SIZE is 16 for SS and 8
>> for HS. The controller loads and updates the TRB cache from the
>> transfer ring in system memory whenever the driver issues a start
>> transfer or update transfer command.
>>
>> For chained TRBs, the Synopsys xHC requires that the total amount of
>> bytes for all TRBs loaded in the TRB cache be greater than or equal to
>> 1 MPS. Or the chain ends within the TRB cache (with a last TRB).
>>
>> If this requirement is not met, the controller will not be able to
>> send or receive a packet and it will hang causing a driver timeout and
>> error.
>>
>> This patch set adds logic to the XHCI driver to detect and prevent this
>> from happening along with the quirk to enable this logic for Synopsys
>> HAPS platform.
>>
>> Based on Mathias's feedback on previous implementation where consolidation
>> was done in TRB cache, with this patch series the implementation is done
>> during mapping of the URB by consolidating the SG list into a temporary
>> buffer if the SG list buffer sizes within TRB_CACHE_SIZE is less than MPS.
>>
>>
>> Tejas Joglekar (4):
>>   dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl
>>   usb: xhci: Set quirk for XHCI_CONSOLIDATE_SG_LIST
>>   usb: dwc3: Add device property consolidate-sgl
>>   usb: xhci: Use temporary buffer to consolidate SG
>>
>> Resending as 'umlaut' is not accepted by some servers in email.
> 
> Only patch 4/4 seems to have gone through :(
> 

Resent the missing patches

Re: [RESENDING RFC PATCH 1/4] dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl

[Greg KH]

On Fri, Mar 27, 2020 at 03:11:56PM +0530, Tejas Joglekar wrote:
> This commit adds the documentation for consolidate-sgl, and
> snps,consolidate-sgl property. These when set enables the quirk for
> XHCI driver for consolidation of sg list into a temporary buffer when small
> buffer sizes are scattered over the sg list not making up to MPS or total
> transfer size within TRB cache size with Synopsys xHC.
> 
> Signed-off-by: Tejas Joglekar <joglekar@synopsys.com>
> ---
>  Documentation/devicetree/bindings/usb/dwc3.txt     | 3 +++
>  Documentation/devicetree/bindings/usb/usb-xhci.txt | 3 +++
>  2 files changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
> index 9946ff9ba735..292d1f7969e4 100644
> --- a/Documentation/devicetree/bindings/usb/dwc3.txt
> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
> @@ -104,6 +104,9 @@ Optional properties:
>  			this and tx-thr-num-pkt-prd to a valid, non-zero value
>  			1-16 (DWC_usb31 programming guide section 1.2.3) to
>  			enable periodic ESS TX threshold.
> + - snps,consolidate-sgl: enable sg list consolidation - host mode only. Set to use
> +			SG buffers of at least MPS size by consolidating smaller SG
> +			buffers list into a single buffer.
>  
>   - <DEPRECATED> tx-fifo-resize: determines if the FIFO *has* to be reallocated.
>   - snps,incr-burst-type-adjustment: Value for INCR burst type of GSBUSCFG0
> diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt b/Documentation/devicetree/bindings/usb/usb-xhci.txt
> index 3f378951d624..a90d853557ee 100644
> --- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
> +++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
> @@ -43,6 +43,9 @@ Optional properties:
>    - quirk-broken-port-ped: set if the controller has broken port disable mechanism
>    - imod-interval-ns: default interrupt moderation interval is 5000ns
>    - phys : see usb-hcd.yaml in the current directory
> +  - consolidate-sgl: indicate if you need to consolidate sg list into a
> +    temporary buffer when small SG buffer sizes does not make upto MPS
> +    size or total transfer size across the TRB cache size.

Shouldn't this refer to the fact that the hardware is broken?  Otherwise
why would anyone know if they should, or should not, enable this option?

thanks,

greg k-h

Re: [RESENDING RFC PATCH 1/4] dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl

[Tejas Joglekar]

Hi,
On 3/27/2020 3:24 PM, Greg KH wrote:
> On Fri, Mar 27, 2020 at 03:11:56PM +0530, Tejas Joglekar wrote:
>> This commit adds the documentation for consolidate-sgl, and
>> snps,consolidate-sgl property. These when set enables the quirk for
>> XHCI driver for consolidation of sg list into a temporary buffer when small
>> buffer sizes are scattered over the sg list not making up to MPS or total
>> transfer size within TRB cache size with Synopsys xHC.
>>
>> Signed-off-by: Tejas Joglekar <joglekar@synopsys.com>
>> ---
>>  Documentation/devicetree/bindings/usb/dwc3.txt     | 3 +++
>>  Documentation/devicetree/bindings/usb/usb-xhci.txt | 3 +++
>>  2 files changed, 6 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
>> index 9946ff9ba735..292d1f7969e4 100644
>> --- a/Documentation/devicetree/bindings/usb/dwc3.txt
>> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
>> @@ -104,6 +104,9 @@ Optional properties:
>>  			this and tx-thr-num-pkt-prd to a valid, non-zero value
>>  			1-16 (DWC_usb31 programming guide section 1.2.3) to
>>  			enable periodic ESS TX threshold.
>> + - snps,consolidate-sgl: enable sg list consolidation - host mode only. Set to use
>> +			SG buffers of at least MPS size by consolidating smaller SG
>> +			buffers list into a single buffer.
>>  
>>   - <DEPRECATED> tx-fifo-resize: determines if the FIFO *has* to be reallocated.
>>   - snps,incr-burst-type-adjustment: Value for INCR burst type of GSBUSCFG0
>> diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt b/Documentation/devicetree/bindings/usb/usb-xhci.txt
>> index 3f378951d624..a90d853557ee 100644
>> --- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
>> +++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
>> @@ -43,6 +43,9 @@ Optional properties:
>>    - quirk-broken-port-ped: set if the controller has broken port disable mechanism
>>    - imod-interval-ns: default interrupt moderation interval is 5000ns
>>    - phys : see usb-hcd.yaml in the current directory
>> +  - consolidate-sgl: indicate if you need to consolidate sg list into a
>> +    temporary buffer when small SG buffer sizes does not make upto MPS
>> +    size or total transfer size across the TRB cache size.
> 
> Shouldn't this refer to the fact that the hardware is broken?  Otherwise
> why would anyone know if they should, or should not, enable this option?
>
We have not seen issue with Linux environment for now. But with other OS with
SG list with very small buffer sizes the xHC controller hang was seen. So 
currently introducing the binding as optional one. One could enable this 
option when xHC halt happens due to small SG list sizes.  
 
> thanks,
> 
> greg k-h
> 

Thanks & Regards,
 Tejas Joglekar

Re: [RESENDING RFC PATCH 1/4] dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl

[Greg KH]

On Fri, Mar 27, 2020 at 10:11:59AM +0000, Tejas Joglekar wrote:
> Hi,
> On 3/27/2020 3:24 PM, Greg KH wrote:
> > On Fri, Mar 27, 2020 at 03:11:56PM +0530, Tejas Joglekar wrote:
> >> This commit adds the documentation for consolidate-sgl, and
> >> snps,consolidate-sgl property. These when set enables the quirk for
> >> XHCI driver for consolidation of sg list into a temporary buffer when small
> >> buffer sizes are scattered over the sg list not making up to MPS or total
> >> transfer size within TRB cache size with Synopsys xHC.
> >>
> >> Signed-off-by: Tejas Joglekar <joglekar@synopsys.com>
> >> ---
> >>  Documentation/devicetree/bindings/usb/dwc3.txt     | 3 +++
> >>  Documentation/devicetree/bindings/usb/usb-xhci.txt | 3 +++
> >>  2 files changed, 6 insertions(+)
> >>
> >> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
> >> index 9946ff9ba735..292d1f7969e4 100644
> >> --- a/Documentation/devicetree/bindings/usb/dwc3.txt
> >> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
> >> @@ -104,6 +104,9 @@ Optional properties:
> >>  			this and tx-thr-num-pkt-prd to a valid, non-zero value
> >>  			1-16 (DWC_usb31 programming guide section 1.2.3) to
> >>  			enable periodic ESS TX threshold.
> >> + - snps,consolidate-sgl: enable sg list consolidation - host mode only. Set to use
> >> +			SG buffers of at least MPS size by consolidating smaller SG
> >> +			buffers list into a single buffer.
> >>  
> >>   - <DEPRECATED> tx-fifo-resize: determines if the FIFO *has* to be reallocated.
> >>   - snps,incr-burst-type-adjustment: Value for INCR burst type of GSBUSCFG0
> >> diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt b/Documentation/devicetree/bindings/usb/usb-xhci.txt
> >> index 3f378951d624..a90d853557ee 100644
> >> --- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
> >> +++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
> >> @@ -43,6 +43,9 @@ Optional properties:
> >>    - quirk-broken-port-ped: set if the controller has broken port disable mechanism
> >>    - imod-interval-ns: default interrupt moderation interval is 5000ns
> >>    - phys : see usb-hcd.yaml in the current directory
> >> +  - consolidate-sgl: indicate if you need to consolidate sg list into a
> >> +    temporary buffer when small SG buffer sizes does not make upto MPS
> >> +    size or total transfer size across the TRB cache size.
> > 
> > Shouldn't this refer to the fact that the hardware is broken?  Otherwise
> > why would anyone know if they should, or should not, enable this option?
> >
> We have not seen issue with Linux environment for now. But with other OS with
> SG list with very small buffer sizes the xHC controller hang was seen. So 
> currently introducing the binding as optional one. One could enable this 
> option when xHC halt happens due to small SG list sizes.  

What I mean is this should be something like,
"quirk-broken-sg-list-handler" or something like that.  Otherwise how
does anyone know if this really is needed or not.  Reading this would
seem like everyone would like to do this, as consolidating links
sounds like a good optimization, when instead this really cause more
memory allocations, making this possibly worse performance.

thanks,

greg k-h

Re: [RESENDING RFC PATCH 1/4] dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl

[Tejas Joglekar]

On 3/27/2020 3:54 PM, Greg KH wrote:
> On Fri, Mar 27, 2020 at 10:11:59AM +0000, Tejas Joglekar wrote:
>> Hi,
>> On 3/27/2020 3:24 PM, Greg KH wrote:
>>> On Fri, Mar 27, 2020 at 03:11:56PM +0530, Tejas Joglekar wrote:
>>>> This commit adds the documentation for consolidate-sgl, and
>>>> snps,consolidate-sgl property. These when set enables the quirk for
>>>> XHCI driver for consolidation of sg list into a temporary buffer when small
>>>> buffer sizes are scattered over the sg list not making up to MPS or total
>>>> transfer size within TRB cache size with Synopsys xHC.
>>>>
>>>> Signed-off-by: Tejas Joglekar <joglekar@synopsys.com>
>>>> ---
>>>>  Documentation/devicetree/bindings/usb/dwc3.txt     | 3 +++
>>>>  Documentation/devicetree/bindings/usb/usb-xhci.txt | 3 +++
>>>>  2 files changed, 6 insertions(+)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
>>>> index 9946ff9ba735..292d1f7969e4 100644
>>>> --- a/Documentation/devicetree/bindings/usb/dwc3.txt
>>>> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
>>>> @@ -104,6 +104,9 @@ Optional properties:
>>>>  			this and tx-thr-num-pkt-prd to a valid, non-zero value
>>>>  			1-16 (DWC_usb31 programming guide section 1.2.3) to
>>>>  			enable periodic ESS TX threshold.
>>>> + - snps,consolidate-sgl: enable sg list consolidation - host mode only. Set to use
>>>> +			SG buffers of at least MPS size by consolidating smaller SG
>>>> +			buffers list into a single buffer.
>>>>  
>>>>   - <DEPRECATED> tx-fifo-resize: determines if the FIFO *has* to be reallocated.
>>>>   - snps,incr-burst-type-adjustment: Value for INCR burst type of GSBUSCFG0
>>>> diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt b/Documentation/devicetree/bindings/usb/usb-xhci.txt
>>>> index 3f378951d624..a90d853557ee 100644
>>>> --- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
>>>> +++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
>>>> @@ -43,6 +43,9 @@ Optional properties:
>>>>    - quirk-broken-port-ped: set if the controller has broken port disable mechanism
>>>>    - imod-interval-ns: default interrupt moderation interval is 5000ns
>>>>    - phys : see usb-hcd.yaml in the current directory
>>>> +  - consolidate-sgl: indicate if you need to consolidate sg list into a
>>>> +    temporary buffer when small SG buffer sizes does not make upto MPS
>>>> +    size or total transfer size across the TRB cache size.
>>>
>>> Shouldn't this refer to the fact that the hardware is broken?  Otherwise
>>> why would anyone know if they should, or should not, enable this option?
>>>
>> We have not seen issue with Linux environment for now. But with other OS with
>> SG list with very small buffer sizes the xHC controller hang was seen. So 
>> currently introducing the binding as optional one. One could enable this 
>> option when xHC halt happens due to small SG list sizes.  
> 
> What I mean is this should be something like,
> "quirk-broken-sg-list-handler" or something like that.  Otherwise how
> does anyone know if this really is needed or not.  Reading this would
> seem like everyone would like to do this, as consolidating links
> sounds like a good optimization, when instead this really cause more
> memory allocations, making this possibly worse performance.
> 
Sure, understood. I will rename this entry.
> thanks,
> 
> greg k-h
> 

Thanks & Regards,
 Tejas Joglekar

Re: [RESENDING RFC PATCH 1/4] dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl

[Rob Herring]

On Fri, Mar 27, 2020 at 03:11:56PM +0530, Tejas Joglekar wrote:
> This commit adds the documentation for consolidate-sgl, and
> snps,consolidate-sgl property. These when set enables the quirk for
> XHCI driver for consolidation of sg list into a temporary buffer when small
> buffer sizes are scattered over the sg list not making up to MPS or total
> transfer size within TRB cache size with Synopsys xHC.
> 
> Signed-off-by: Tejas Joglekar <joglekar@synopsys.com>
> ---
>  Documentation/devicetree/bindings/usb/dwc3.txt     | 3 +++
>  Documentation/devicetree/bindings/usb/usb-xhci.txt | 3 +++
>  2 files changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
> index 9946ff9ba735..292d1f7969e4 100644
> --- a/Documentation/devicetree/bindings/usb/dwc3.txt
> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
> @@ -104,6 +104,9 @@ Optional properties:
>  			this and tx-thr-num-pkt-prd to a valid, non-zero value
>  			1-16 (DWC_usb31 programming guide section 1.2.3) to
>  			enable periodic ESS TX threshold.
> + - snps,consolidate-sgl: enable sg list consolidation - host mode only. Set to use
> +			SG buffers of at least MPS size by consolidating smaller SG
> +			buffers list into a single buffer.

The preference is not to keep adding properties for every single quirk 
or feature. These should be implied by specific compatibles. As Synopsys 
knows what quirks/errata/features are in each version of IP, the 
compatible strings should reflect those versions. (And yes, I'm sure 
there's customer ECO fixes that aren't reflected in the version, but 
that's why we have SoC specific compatibles too.) This is the only way 
we can fix quirks in the OS without doing DT updates. For comparison, do 
you want to have to update your PC BIOS so an OS can work-around issues?

Rob

Re: [RESENDING RFC PATCH 1/4] dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl

[Tejas Joglekar]

Hi,
On 4/5/2020 7:15 AM, Rob Herring wrote:
> On Fri, Mar 27, 2020 at 03:11:56PM +0530, Tejas Joglekar wrote:
>> This commit adds the documentation for consolidate-sgl, and
>> snps,consolidate-sgl property. These when set enables the quirk for
>> XHCI driver for consolidation of sg list into a temporary buffer when small
>> buffer sizes are scattered over the sg list not making up to MPS or total
>> transfer size within TRB cache size with Synopsys xHC.
>>
>> Signed-off-by: Tejas Joglekar <joglekar@synopsys.com>
>> ---
>>  Documentation/devicetree/bindings/usb/dwc3.txt     | 3 +++
>>  Documentation/devicetree/bindings/usb/usb-xhci.txt | 3 +++
>>  2 files changed, 6 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
>> index 9946ff9ba735..292d1f7969e4 100644
>> --- a/Documentation/devicetree/bindings/usb/dwc3.txt
>> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
>> @@ -104,6 +104,9 @@ Optional properties:
>>  			this and tx-thr-num-pkt-prd to a valid, non-zero value
>>  			1-16 (DWC_usb31 programming guide section 1.2.3) to
>>  			enable periodic ESS TX threshold.
>> + - snps,consolidate-sgl: enable sg list consolidation - host mode only. Set to use
>> +			SG buffers of at least MPS size by consolidating smaller SG
>> +			buffers list into a single buffer.
> 
> The preference is not to keep adding properties for every single quirk 
> or feature. These should be implied by specific compatibles. As Synopsys 
> knows what quirks/errata/features are in each version of IP, the 
> compatible strings should reflect those versions. (And yes, I'm sure 
> there's customer ECO fixes that aren't reflected in the version, but 
> that's why we have SoC specific compatibles too.) This is the only way 
> we can fix quirks in the OS without doing DT updates. For comparison, do 
> you want to have to update your PC BIOS so an OS can work-around issues?
>
Yes, I understand what you want to say here. But I think this compatible string
does not work with the platform drivers with PCI based systems. So based on the vendor 
id and device id then I need to set the quirk required. 

@Felipe: What do you suggest for setting up quirk without the DT update for dwc3?
 
> Rob
> 

Thanks & Regards,
 Tejas Joglekar

Re: [RESENDING RFC PATCH 1/4] dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl

[Felipe Balbi]

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Hi,

Tejas Joglekar <Tejas.Joglekar@synopsys.com> writes:
> Hi,
> On 4/5/2020 7:15 AM, Rob Herring wrote:
>> On Fri, Mar 27, 2020 at 03:11:56PM +0530, Tejas Joglekar wrote:
>>> This commit adds the documentation for consolidate-sgl, and
>>> snps,consolidate-sgl property. These when set enables the quirk for
>>> XHCI driver for consolidation of sg list into a temporary buffer when small
>>> buffer sizes are scattered over the sg list not making up to MPS or total
>>> transfer size within TRB cache size with Synopsys xHC.
>>>
>>> Signed-off-by: Tejas Joglekar <joglekar@synopsys.com>
>>> ---
>>>  Documentation/devicetree/bindings/usb/dwc3.txt     | 3 +++
>>>  Documentation/devicetree/bindings/usb/usb-xhci.txt | 3 +++
>>>  2 files changed, 6 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
>>> index 9946ff9ba735..292d1f7969e4 100644
>>> --- a/Documentation/devicetree/bindings/usb/dwc3.txt
>>> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
>>> @@ -104,6 +104,9 @@ Optional properties:
>>>  			this and tx-thr-num-pkt-prd to a valid, non-zero value
>>>  			1-16 (DWC_usb31 programming guide section 1.2.3) to
>>>  			enable periodic ESS TX threshold.
>>> + - snps,consolidate-sgl: enable sg list consolidation - host mode only. Set to use
>>> +			SG buffers of at least MPS size by consolidating smaller SG
>>> +			buffers list into a single buffer.
>> 
>> The preference is not to keep adding properties for every single quirk 
>> or feature. These should be implied by specific compatibles. As Synopsys 
>> knows what quirks/errata/features are in each version of IP, the 
>> compatible strings should reflect those versions. (And yes, I'm sure 
>> there's customer ECO fixes that aren't reflected in the version, but 
>> that's why we have SoC specific compatibles too.) This is the only way 
>> we can fix quirks in the OS without doing DT updates. For comparison, do 
>> you want to have to update your PC BIOS so an OS can work-around issues?
>>
> Yes, I understand what you want to say here. But I think this compatible string
> does not work with the platform drivers with PCI based systems. So based on the vendor 
> id and device id then I need to set the quirk required. 
>
> @Felipe: What do you suggest for setting up quirk without the DT update for dwc3?

We have been using Synopsys controller's revision register, but that's
not visible to xhci driver and we don't have a separate compatible for
each synopsys version on the xhci driver side. One option would be to
add "snps,xhci-foo-bar" to xhci-plat and use that.

-- 
balbi

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Re: [RESENDING RFC PATCH 1/4] dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl

[Tejas Joglekar]

Hi,
On 4/16/2020 1:52 PM, Felipe Balbi wrote:
> 
> Hi,
> 
> Tejas Joglekar <Tejas.Joglekar@synopsys.com> writes:
>> Hi,
>> On 4/5/2020 7:15 AM, Rob Herring wrote:
>>> On Fri, Mar 27, 2020 at 03:11:56PM +0530, Tejas Joglekar wrote:
>>>> This commit adds the documentation for consolidate-sgl, and
>>>> snps,consolidate-sgl property. These when set enables the quirk for
>>>> XHCI driver for consolidation of sg list into a temporary buffer when small
>>>> buffer sizes are scattered over the sg list not making up to MPS or total
>>>> transfer size within TRB cache size with Synopsys xHC.
>>>>
>>>> Signed-off-by: Tejas Joglekar <joglekar@synopsys.com>
>>>> ---
>>>>  Documentation/devicetree/bindings/usb/dwc3.txt     | 3 +++
>>>>  Documentation/devicetree/bindings/usb/usb-xhci.txt | 3 +++
>>>>  2 files changed, 6 insertions(+)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
>>>> index 9946ff9ba735..292d1f7969e4 100644
>>>> --- a/Documentation/devicetree/bindings/usb/dwc3.txt
>>>> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
>>>> @@ -104,6 +104,9 @@ Optional properties:
>>>>  			this and tx-thr-num-pkt-prd to a valid, non-zero value
>>>>  			1-16 (DWC_usb31 programming guide section 1.2.3) to
>>>>  			enable periodic ESS TX threshold.
>>>> + - snps,consolidate-sgl: enable sg list consolidation - host mode only. Set to use
>>>> +			SG buffers of at least MPS size by consolidating smaller SG
>>>> +			buffers list into a single buffer.
>>>
>>> The preference is not to keep adding properties for every single quirk 
>>> or feature. These should be implied by specific compatibles. As Synopsys 
>>> knows what quirks/errata/features are in each version of IP, the 
>>> compatible strings should reflect those versions. (And yes, I'm sure 
>>> there's customer ECO fixes that aren't reflected in the version, but 
>>> that's why we have SoC specific compatibles too.) This is the only way 
>>> we can fix quirks in the OS without doing DT updates. For comparison, do 
>>> you want to have to update your PC BIOS so an OS can work-around issues?
>>>
>> Yes, I understand what you want to say here. But I think this compatible string
>> does not work with the platform drivers with PCI based systems. So based on the vendor 
>> id and device id then I need to set the quirk required. 
>>
>> @Felipe: What do you suggest for setting up quirk without the DT update for dwc3?
> 
> We have been using Synopsys controller's revision register, but that's
> not visible to xhci driver and we don't have a separate compatible for
> each synopsys version on the xhci driver side. One option would be to
> add "snps,xhci-foo-bar" to xhci-plat and use that.
> 
@Felipe: Thanks for suggestion

@Mathias: Do you prefer parameter passed this way? I can send the v2 patch set,
after your input.


Thanks & Regards,
 Tejas Joglekar 

Re: [RESENDING RFC PATCH 1/4] dt-bindings: usb: Add snps,consolidate-sgl & consolidate-sgl

[Mathias Nyman]

On 16.4.2020 19.37, Tejas Joglekar wrote:
> Hi,
> On 4/16/2020 1:52 PM, Felipe Balbi wrote:
>>
>> Hi,
>>
>> Tejas Joglekar <Tejas.Joglekar@synopsys.com> writes:
>>> Hi,
>>> On 4/5/2020 7:15 AM, Rob Herring wrote:
>>>> On Fri, Mar 27, 2020 at 03:11:56PM +0530, Tejas Joglekar wrote:
>>>>> This commit adds the documentation for consolidate-sgl, and
>>>>> snps,consolidate-sgl property. These when set enables the quirk for
>>>>> XHCI driver for consolidation of sg list into a temporary buffer when small
>>>>> buffer sizes are scattered over the sg list not making up to MPS or total
>>>>> transfer size within TRB cache size with Synopsys xHC.
>>>>>
>>>>> Signed-off-by: Tejas Joglekar <joglekar@synopsys.com>
>>>>> ---
>>>>>  Documentation/devicetree/bindings/usb/dwc3.txt     | 3 +++
>>>>>  Documentation/devicetree/bindings/usb/usb-xhci.txt | 3 +++
>>>>>  2 files changed, 6 insertions(+)
>>>>>
>>>>> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
>>>>> index 9946ff9ba735..292d1f7969e4 100644
>>>>> --- a/Documentation/devicetree/bindings/usb/dwc3.txt
>>>>> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
>>>>> @@ -104,6 +104,9 @@ Optional properties:
>>>>>  			this and tx-thr-num-pkt-prd to a valid, non-zero value
>>>>>  			1-16 (DWC_usb31 programming guide section 1.2.3) to
>>>>>  			enable periodic ESS TX threshold.
>>>>> + - snps,consolidate-sgl: enable sg list consolidation - host mode only. Set to use
>>>>> +			SG buffers of at least MPS size by consolidating smaller SG
>>>>> +			buffers list into a single buffer.
>>>>
>>>> The preference is not to keep adding properties for every single quirk 
>>>> or feature. These should be implied by specific compatibles. As Synopsys 
>>>> knows what quirks/errata/features are in each version of IP, the 
>>>> compatible strings should reflect those versions. (And yes, I'm sure 
>>>> there's customer ECO fixes that aren't reflected in the version, but 
>>>> that's why we have SoC specific compatibles too.) This is the only way 
>>>> we can fix quirks in the OS without doing DT updates. For comparison, do 
>>>> you want to have to update your PC BIOS so an OS can work-around issues?
>>>>
>>> Yes, I understand what you want to say here. But I think this compatible string
>>> does not work with the platform drivers with PCI based systems. So based on the vendor 
>>> id and device id then I need to set the quirk required. 
>>>
>>> @Felipe: What do you suggest for setting up quirk without the DT update for dwc3?
>>
>> We have been using Synopsys controller's revision register, but that's
>> not visible to xhci driver and we don't have a separate compatible for
>> each synopsys version on the xhci driver side. One option would be to
>> add "snps,xhci-foo-bar" to xhci-plat and use that.
>>
> @Felipe: Thanks for suggestion
> 
> @Mathias: Do you prefer parameter passed this way? I can send the v2 patch set,
> after your input.

should work, I don't see any issues with that.

-Mathias