Re: [PATCH] MIPS: NI 169445 board support

Joao Pinto
2017-01-05T18:33:53Z

Hi,

Às 6:28 PM de 1/5/2017, Niklas Cassel escreveu:
> On 01/04/2017 05:38 PM, Nathan Sullivan wrote:
>> On Tue, Dec 20, 2016 at 05:34:34PM +0100, Ralf Baechle wrote:
>>> On Fri, Dec 02, 2016 at 09:42:09AM -0600, Nathan Sullivan wrote:
>>>> Date: Fri, 2 Dec 2016 09:42:09 -0600
>>>> From: Nathan Sullivan <nathan.sullivan@ni.com>
>>>> To: ralf@linux-mips.org, mark.rutland@arm.com, robh+dt@kernel.org
>>>> CC: linux-mips@linux-mips.org, devicetree@vger.kernel.org,
>>>> linux-kernel@vger.kernel.org, Nathan Sullivan <nathan.sullivan@ni.com>
>>>> Subject: [PATCH] MIPS: NI 169445 board support
>>>> Content-Type: text/plain
>>>>
>>>> Support the National Instruments 169445 board.
>>> Nathan,
>>>
>>> I assume you're going to repost the changes Rob asked for in
>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__patchwork.linux-2Dmips.org_patch_14641_-2326924&d=DgICaQ&c=DPL6_X_6JkXFx7AXWqB0tg&r=s2fO0hii0OGNOv9qQy_HRXy-xAJUD1NNoEcc3io_kx0&m=5p7f9dIkvVVK4UFHimMpezq5NwIJfUpd08c-Zk4_c6c&s=_JwSwe4VFYtxV1tcYt6Z8r4hJX0xfoGhCixygUxlg5s&e= and resubmit?
>>>
>>> Thanks,
>>>
>>> Ralf
>> Hmm, I found the issue with the generic MIPS config and dwc_eth_qos. The NIC
>> driver attempts to cache align a descriptor ring using the ___cacheline_aligned
>> attribute on the descriptor struct, in combination with a "skip" feature in
>> hardware. However, the skip feature only has a three bit field, and the generic
>> MIPS config selects MIPS_L1_CACHE_SHIFT_7. So, the line size is 128, and with a
>> 64-bit bus, that means the NIC descriptor skip field would need to be set to
>> 14 to align the 16-byte descriptors...
>>
>> I guess it makes sense for a generic MIPS kernel to align everything for 128 byte
>> cache lines, and for me to fix the dwc_eth_qos driver to handle cases where the
>> line size is too big for the hardware skip feature, right?
>
> I don't know if you've been following the discussion regarding
> dwc_eth_qos on netdev, but Joao Pinto from Synopsys is
> planning on removing the driver (since the stmmac driver
> now supports the same version of the IP, together with older
> versions of the IP).
>
> Since device tree bindings are treated as an ABI,
> Joao has implemented a glue layer for stmmac that parses
> the dwc_eth_qos binding, but uses stmmac under the hood.
>
> You can use any of the bindings, but since the dwc_eth_qos
> binding will be marked as deprecated, you might want to
> consider moving to the stmmac binding.

A patch set to port dwc_eth_qos to stmmac is at this moment under review:

http://patchwork.ozlabs.org/patch/711428/
http://patchwork.ozlabs.org/patch/711438/
http://patchwork.ozlabs.org/patch/711439/

Niklas has tested it and it works well, so after the patches are upstreamed the
dwc_eth_qos will be removed as agreed with Lars.

Thanks.

>
>>
>> Thanks,
>>
>> Nathan
>>
>>
>