[meta-xilinx] [PATCH 0/5] Use kernel device tree when we can

[Nathan Rossi]

On Thu, Nov 5, 2015 at 11:08 PM, Joe Nicholson <joe at joenicholson.co.uk> wrote:
> Hi Nathan
>
> We're still using linux-xlnx 3.14 on one project.  We're quite keen to move
> to mainline, but for us to be able to it needs PL support and a higher
> performance Ethernet driver (we had to move from macb to Emacps to get the
> transfer speeds we needed).

Any reason against moving to a newer linux-xlnx kernel, or just not
worth the time investment? It is just that the 3.14 kernel is quite
old now.

>
> Are these now merged into linux-yocto?  If so, no objections at all!

PL support is not in linux-yocto yet, but it is in linux-next and will
make it into 4.4 is my understanding
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/tree/drivers/fpga/zynq-fpga.c
(Thanks Moritz! :D), planning on looking into getting it going (maybe
backport?) once I have sorted the jethro branching. As for macb, I
haven't done any benchmarks recently but changes keep happening so it
might be worth looking at the performance again for your setup when
the kernel with PL support becomes available.

Regards,
Nathan

>
> Cheers!
>
> Joe
>
>
> -----Original Message-----
> From: meta-xilinx-bounces at yoctoproject.org
> [mailto:meta-xilinx-bounces at yoctoproject.org] On Behalf Of Nathan Rossi
> Sent: 05 November 2015 02:07
> To: Manjukumar Harthikote Matha <manjukumar.harthikote-matha at xilinx.com>
> Cc: meta-xilinx at yoctoproject.org
> Subject: Re: [meta-xilinx] [PATCH 0/5] Use kernel device tree when we can
>
> On Thu, Nov 5, 2015 at 11:48 AM, Manjukumar Harthikote Matha
> <manjukumar.harthikote-matha at xilinx.com> wrote:
>> On 11/04/2015 04:08 PM, Nathan Rossi wrote:
>>>
>>> On Thu, Nov 5, 2015 at 8:02 AM, Manjukumar Matha
>>> <manjukumar.harthikote-matha at xilinx.com> wrote:
>>>>
>>>> This series simplifies some meta-xilinx machine definitions by
>>>> removing their device tree files and using the kernel device tree
>>>> definitions instead.
>>>
>>>
>>> These changes are definitely the goal, however due to some
>>> in-consistency with the device trees in older kernels (v3.19)
>>> meta-xilinx is not quite ready to do the switch over. Before doing
>>> these changes I was planning on getting the meta-xilinx device trees
>>> moved over to the same base include that is used in the kernel.
>>> Alongside those changes I was looking into deprecating the whole
>>> conf/machine/boards in favour of a more standardized BSP layout, so
>>> as to better set-up for supporting more boards/machines.
>>>
>>
>> Thanks.
>>
>> What has been the practice so far on maintaining/dropping support for
>> earlier kernels? For instance, could we drop support for v3.14 (and
>> maybe
>> v3.19) on jethro? We can of course continue supporting both versions
>> on fido.
>
> There has not been any specific rules/practices, i've just gone with the
> flow. However I would like to reduce the number of linux-xlnx kernel
> versions that are kept around across releases. For jethro I don't plan on
> dropping any kernel versions (primarily due to timing), but I planning to
> drop the linux-xlnx 3.14 and 3.19 recipes afterwards (as long as there are
> no objections), but linux-yocto will still have
> 3.14 and 3.19 at least for now so dropping them purely to achieve the kernel
> dts goal is a bit problematic, maybe once 3.14 is gone minimal patching of
> linux-yocto 3.19 will put us on track for kernel device trees.
>
> Regards,
> Nathan
>
>>
>>> Also the zybo device trees are missing some nodes (in linux-xlnx and
>>> mainline), so that one should still use the layers dts for now.
>>>
>> Thanks for the heads up on Zybo.
>> We will work on this issue and get linux-xlnx updated
>>
>> Thanks
>> Manju
>>
>>
> --
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