Re: [PATCH net-next V3 1/3] dt-bindings: net: xilinx_axienet: Introduce dmaengine binding support

[Krzysztof Kozlowski]

On 11/05/2023 13:32, Gaddam, Sarath Babu Naidu wrote:
> 
> 
>> -----Original Message-----
>> From: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
>> Sent: Wednesday, May 10, 2023 3:39 PM
>> To: Gaddam, Sarath Babu Naidu
>> <sarath.babu.naidu.gaddam@xxxxxxx>; davem@xxxxxxxxxxxxx;
>> edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx; pabeni@xxxxxxxxxx;
>> robh+dt@xxxxxxxxxx; krzysztof.kozlowski+dt@xxxxxxxxxx
>> Cc: linux@xxxxxxxxxxxxxxx; Simek, Michal <michal.simek@xxxxxxx>;
>> Pandey, Radhey Shyam <radhey.shyam.pandey@xxxxxxx>;
>> netdev@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-arm-
>> kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Sarangi,
>> Anirudha <anirudha.sarangi@xxxxxxx>; Katakam, Harini
>> <harini.katakam@xxxxxxx>; git (AMD-Xilinx) <git@xxxxxxx>
>> Subject: Re: [PATCH net-next V3 1/3] dt-bindings: net: xilinx_axienet:
>> Introduce dmaengine binding support
>>
>> On 10/05/2023 10:50, Sarath Babu Naidu Gaddam wrote:
>>> From: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxxxxx>
>>>
>>> The axiethernet driver will use dmaengine framework to communicate
>>> with dma controller IP instead of built-in dma programming sequence.
>>
>> Subject: drop second/last, redundant "bindings". The "dt-bindings"
>> prefix is already stating that these are bindings.
>>
>> Actually also drop "dmaenging" as it is Linuxism. Focus on hardware, e.g.
>> "Add DMA support".
>>
>>>
>>> To request dma transmit and receive channels the axiethernet driver
>>> uses generic dmas, dma-names properties.
>>>
>>> Also to support the backward compatibility, use "dmas" property to
>>> identify as it should use dmaengine framework or legacy
>>> driver(built-in dma programming).
>>>
>>> At this point it is recommended to use dmaengine framework but it's
>>> optional. Once the solution is stable will make dmas as required
>>> properties.
>>>
>>> Signed-off-by: Radhey Shyam Pandey
>> <radhey.shyam.pandey@xxxxxxxxxx>
>>> Signed-off-by: Sarath Babu Naidu Gaddam
>>> <sarath.babu.naidu.gaddam@xxxxxxx>
>>> ---
>>> These changes are on top of below txt to yaml conversion discussion
>>> https://lore.kernel.org/all/20230308061223.1358637-1-
>> sarath.babu.naidu
>>> .gaddam@xxxxxxx/#Z2e.:20230308061223.1358637-1-
>> sarath.babu.naidu.gadda
>>> m::40amd.com:1bindings:net:xlnx::2caxi-ethernet.yaml
>>>
>>> Changes in V3:
>>> 1) Reverted reg and interrupts property to  support backward
>> compatibility.
>>> 2) Moved dmas and dma-names properties from Required properties.
>>>
>>> Changes in V2:
>>> - None.
>>> ---
>>>  .../devicetree/bindings/net/xlnx,axi-ethernet.yaml   | 12
>> ++++++++++++
>>>  1 file changed, 12 insertions(+)
>>>
>>> diff --git
>>> a/Documentation/devicetree/bindings/net/xlnx,axi-ethernet.yaml
>>> b/Documentation/devicetree/bindings/net/xlnx,axi-ethernet.yaml
>>> index 80843c177029..9dfa1976e260 100644
>>> --- a/Documentation/devicetree/bindings/net/xlnx,axi-ethernet.yaml
>>> +++ b/Documentation/devicetree/bindings/net/xlnx,axi-ethernet.yaml
>>> @@ -122,6 +122,16 @@ properties:
>>>        modes, where "pcs-handle" should be used to point to the PCS/PMA
>> PHY,
>>>        and "phy-handle" should point to an external PHY if exists.
>>>
>>> +  dmas:
>>> +    items:
>>> +      - description: TX DMA Channel phandle and DMA request line
>> number
>>> +      - description: RX DMA Channel phandle and DMA request line
>>> + number
>>> +
>>> +  dma-names:
>>> +    items:
>>> +      - const: tx_chan0
>>
>> tx
>>
>>> +      - const: rx_chan0
>>
>> rx
> 
> We want to support more channels in the future, currently we support
> AXI DMA which has only one tx and rx channel. In future we want to 
> extend support for multichannel DMA (MCDMA) which has 16 TX and
> 16 RX channels. To uniquely identify each channel, we are using chan
> suffix. Depending on the usecase AXI ethernet driver can request any
> combination of multichannel DMA  channels.
> 
> dma-names = tx_chan0, tx_chan1, rx_chan0, rx_chan1;
> 
> will update the commit message with same.

I expect the binding to be complete, otherwise you get comments like
this. Add missing parts to the binding and resend.

Best regards,
Krzysztof