Re: [PATCH] ARM: tegra: Remove 0, prefix from unit-addresses

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On Mon, Apr 11, 2016 at 10:05:21AM -0600, Stephen Warren wrote:
> On 04/11/2016 08:01 AM, Thierry Reding wrote:
> > From: Thierry Reding <treding@xxxxxxxxxx>
> > 
> > When Tegra124 support was first merged the unit-addresses of all devices
> > were listed with a "0," prefix to encode the reg property's second cell.
> > It turns out that this notation is not correct, and the "," separator is
> > only used to separate fields in the unit address (such as the device and
> > function number in PCI devices), not individual cells for addresses with
> > more than one cell.
> 
> > diff --git a/arch/arm/boot/dts/tegra124-jetson-tk1.dts b/arch/arm/boot/dts/tegra124-jetson-tk1.dts
> 
> > -	gpu@0,57000000 {
> > +	gpu@57000000 {
> >   		/*
> >   		 * Node left disabled on purpose - the bootloader will enable
> >   		 * it after having set the VPR up
> 
> So the bootloader doesn't actually do that for the new node name at present.
> I have written a patch to make it do so, but haven't sent it yet since I
> wrote it in the middle of a large cleanup of U-Boot. I expect I can shuffle
> it to the front of the series and send it soon though. Without a new
> bootloader that contains this change, IIUC all graphics will be
> non-operative if this change is applied.

Ah, that's unfortunate. Would it be possible to make the bootloader look
at the reg property for the matching, rather than at the node name? That
might prevent such issues in the future.

Actually, a match on both the compatible and reg might be necessary. Not
that it's likely that there will ever be two devices at the same address
but perhaps to make it explicit what type of device is being enabled.

I'll hold off on this until a version of U-Boot is released that will
contain a fix for this. Do you think it would make v2016.06?

Thierry

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