Re: [PATCH] MIPS: NI 169445 board support

Joao Pinto
2017-01-05T18:45:26Z

Às 6:44 PM de 1/5/2017, Nathan Sullivan escreveu:
> On Thu, Jan 05, 2017 at 06:33:53PM +0000, Joao Pinto wrote:
>> 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:
>>
>> https://urldefense.proofpoint.com/v2/url?u=http-3A__patchwork.ozlabs.org_patch_711428_&d=DgIDAw&c=DPL6_X_6JkXFx7AXWqB0tg&r=s2fO0hii0OGNOv9qQy_HRXy-xAJUD1NNoEcc3io_kx0&m=E0wkLvWGNBx49Zdq7Jw5toxfcwI9r7MBBbcTea28AL0&s=P71GK8K8tyGjenB4tDVyKfCuZF9cZiFBBpdeX8PQtEM&e=
>> https://urldefense.proofpoint.com/v2/url?u=http-3A__patchwork.ozlabs.org_patch_711438_&d=DgIDAw&c=DPL6_X_6JkXFx7AXWqB0tg&r=s2fO0hii0OGNOv9qQy_HRXy-xAJUD1NNoEcc3io_kx0&m=E0wkLvWGNBx49Zdq7Jw5toxfcwI9r7MBBbcTea28AL0&s=fj787JEefx7cddQAe7g604tMtvDlVzYj3kQKy80Gym0&e=
>> https://urldefense.proofpoint.com/v2/url?u=http-3A__patchwork.ozlabs.org_patch_711439_&d=DgIDAw&c=DPL6_X_6JkXFx7AXWqB0tg&r=s2fO0hii0OGNOv9qQy_HRXy-xAJUD1NNoEcc3io_kx0&m=E0wkLvWGNBx49Zdq7Jw5toxfcwI9r7MBBbcTea28AL0&s=Cyy9ySM6LNgkQ07OsIYE8KnD1h1DruhCKLxH6W3_1VY&e=
>>
>> 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 for the heads up, I'll wait, adjust my bindings and retest then.

Great! Thanks!

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