Re: Fwd: Micrel KSZ9031RN PHY problem

[Guillermo Rodriguez Garcia <guille.rodriguez@gmail.com>]

Hello,

2016-04-21 9:32 GMT+02:00 Sascha Hauer <s.hauer@pengutronix.de>:
> On Wed, Apr 20, 2016 at 05:58:40PM +0200, Guillermo Rodriguez Garcia wrote:
>> Hello,
>>
>> 2016-04-19 9:11 GMT+02:00 Sascha Hauer <s.hauer@pengutronix.de>:
>> > Hi Guillermo,
>> >
>> > +Cc Philipp Zabel who ported the patch to barebox
>> >
>> > On Mon, Apr 18, 2016 at 04:49:47PM +0200, Guillermo Rodriguez Garcia wrote:
>> >> Hello all,
>> >>
>> >> I am playing with barebox on an Atmel SAMA5D3 Xplained board. It is
>> >> now working fine for the most part, however after updating to the
>> >> latest sources from git I found a problem that I had not seen before.
>> >>
>> >> This board has two Ethernet interfaces; eth0 uses a Micrel KSZ9031RN
>> >> PHY, and eth1 uses a Micrel KSZ8081RNB PHY.
>> >>
>> >> It seems that after release 2016.03.0, eth0 does not work anymore with
>> >> some routers. Specifically I found this problem with a Comtrend
>> >> VG-8050. I have tested other routers and the problem was not present
>> >> there.
>> >>
>> >> After some research it seems that the problem is caused by this
>> >> commit: http://git.pengutronix.de/?p=barebox.git;a=commit;h=da89ee8f2e04e116410632a185024f58b8262d87
>> >>
>> >> Before this commit eth0 was working fine. After this commit, the link
>> >> cannot established anymore:
>> >>
>> >> [...]
>> >> barebox:/# ping 192.168.0.128
>> >> ping failed: Network is down
>> >>
>> >> Before diving further into this I thought it could be a good idea to
>> >> ask, in case someone can shed some light here.
>> >
>> > I have no idea what the issue is here. We might have to make this option
>> > configurable via devicetree to give boards different options. Since the
>> > patch comes from the Linux Kernel, do you have the same problems under
>> > Linux?
>>
>> I'm trying to get the latest kernel to boot. The latest version
>> supported by Atmel is 4.1, which doesn't have the patch yet. Will
>> report back asap.
>
> Thanks. We can revert this patch since Philipp only ported it to stay in
> sync with the kernel. Anyway, if it makes problems we'll probably need a
> solution for the kernel aswell.

Linux kernel 4.3 which incorporates the patch works fine (!)

On the other hand, U-Boot 2016.03, which also incorporates a
center_flp_timing patch
(http://www.spinics.net/lists/u-boot-v2/msg25938.html) also shows the
same problem as Barebox.

This is puzzling. The timings patch in kernel version 4.3 works fine,
but seems to cause problems in both Barebox and U-Boot.

Still investigating.

Guillermo Rodriguez Garcia
guille.rodriguez@gmail.com

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