Re: [PATCH v4 1/2] arm64: dts: lx2160a: update PCIe nodes to match rev2 silicon

Russell King (Oracle)
2022-09-12T20:33:50Z

On Mon, Sep 12, 2022 at 11:54:06AM -0700, Olof Johansson wrote:
> On Mon, Sep 12, 2022 at 12:05 AM Olof Johansson <olof@lixom.net> wrote:
> >
> > Hi,
> >
> > On Wed, Aug 17, 2022 at 1:26 PM Li Yang <leoyang.li@nxp.com> wrote:
> > >
> > > The original dts was created based on the non-production rev1 silicon
> > > which was only used for evaluation. Update the PCIe nodes to align with
> > > the different controller used in production rev2 silicon.
> >
> > How can I confirm what version of silicon I have on a system?
> >
> > My non-evaluation commercially purchased system (HoneyComb LX2K) has:
> >
> > # cat /sys/bus/soc/devices/soc0/revision
> > 1.0
> >
> > And I will be really grumpy if this system stops working. It's what I
> > use to do all my maintainer work, even if that's been fairly dormant
> > this year.
> >
> > It's overall setting off red flags to update an in-place devicetree to
> > a "new revision" of silicon instead of adding a new DT for said
> > revision. 2160A has been on the market for several years, so it just
> > seems odd to all of the sudden retroactively make things
> > non-backwards-compatible.
>
> Confirmed that this patch renders my HoneyComb unbootable -- PCIe doesn't probe.
>
> Shawn, please revert, and be on the lookout for similar problematic
> approaches in the future. Thanks!

I think you may also need to beware of the MC firmware revision - I
seem to remember reading in the changelog notes for it that NXP
dropped support in the MC firmware for the older silicon, though I
may be misremembering. It's been a while since I really looked at
the LX2160A from the point of view of maintaining or developing
anything for it.

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