Re: [Xen-devel] [PATCH v2] xen/arm: platform: fix Raspberry Pi compatible string

[Julien Grall <julien.grall@xxxxxxx>]

Hi,

On 10/9/19 5:59 PM, Stewart Hildebrand wrote:
> On Wednesday, October 9, 2019 11:30 AM, Julien Grall <julien.grall@xxxxxxx> 
> wrote:
> > On 04/10/2019 01:47, Stewart Hildebrand wrote:
> > > Both upstream [1] and downstream [2] Linux kernels use "brcm,bcm2711"
> > > as the compatible string for Raspberry Pi 4. Add this string to our
> > > platform compatible list.
> > Did the RPI foundation released any kernel with the old binding?
> Sure, I see the following tags in their linux tree since initial RPi4
> support until the binding was updated:
> raspberrypi-kernel_1.20190709-1
> raspberrypi-kernel_1.20190718-1
> raspberrypi-kernel_1.20190819-1
> raspberrypi-kernel_1.20190925-1
>
> These correspond with their binary releases at [3], except the binary
> releases also have an earlier 1.20190620+1 tag with RPi4 support.
>
> However, even with Xen looking for bcm2838, you wouldn't be able to
> grab one of those releases and boot without running into other issues.
> You'd still need a couple of additional patches at [4]. Currently the
> only way that I'm aware of to successfully boot into dom0 and launch
> domU is to build the dom0 kernel from source with the extra patches
> applied found at [4].
Is there any plan to upstream those patches?

> > If so, I am ok if we don't support the compatible in Xen (we don't have a
> > release with it yet!), but it would be worth mentioning in the commit message
> > that this is going to break for some users (TBD) so they need to upgrade.
> See below for suggestion.
>
> > @Juergen: I would like to consider this patch for Xen 4.13. This is limited to
> > RPI4 and would avoid us to ship it with a compatible that is going to disappear.
> >
> > > The brcm,bcm2838 convention is abandoned. Remove it.
> > >
> > > Rename the variables within the file to a rpi4_* prefix since the file
> > > is meant to cover the Raspberry Pi 4 platform.
> "If you are using a device tree with the old compatible string
> brcm,bcm2838, you will need to upgrade your device tree to one that has
> the new brcm,bcm2711 compatible string."
That's fine with me.

Cheers,

--
Julien Grall

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