[Linux-stm32] [PATCH v2 2/2] net: stmmac: Add Ingenic SoCs MAC support.

[Zhou Yanjie]

Hi Andrew,

On 2021/6/10 下午8:27, Zhou Yanjie wrote:
>
> Hi Andrew,
>
> On 2021/6/10 下午8:15, Andrew Lunn wrote:
>>> The manual does not tell how much ps a unit is.
>>>
>>> I am confirming with Ingenic, but there is no reply
>>>
>>> at the moment. Can we follow Rockchip's approach?
>>>
>>> According to the description in "rockchip-dwmac.yaml"
>>>
>>> and the related code in "dwmac-rk.c", it seems that their
>>>
>>> delay parameter seems to be the value used by the hardware
>>>
>>> directly instead of ps.
>> We are much more strict about this now than before. You have to use
>> standard units and convert to hardware values. It also makes it a lot
>> easier for DT writers, if they have an idea what the units mean.
>>
>> Having the MAC add small delays is something you can add later,
>> without breaking backwards compatibility. So if you cannot determine
>> what the units are now, just submit the glue driver without support
>> for this feature. If anybody really needs it, they can do the needed
>> research, maybe do some measurements, and then add the code.
>
>
> *I did an experiment, when the tx delay is not set, RGMII works a
> *
>
> *little abnormally. It seems I have to wait for Ingenic's reply...*
>

Here is Ingenic's reply, the time length corresponding to a unit is 
19.5ps (19500fs).


>
>>      Andrew
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