Re: [PATCH 0/8] Add support for Qualcomm SA8155-ADP board

[Stephan Gerhold <stephan@gerhold.net>]

On Fri, Mar 01, 2024 at 06:25:39PM +0000, Volodymyr Babchuk wrote:
> Caleb Connolly <caleb.connolly@linaro.org> writes:
> > On 29/02/2024 14:21, Volodymyr Babchuk wrote:
> >> This patch series adds support for Qualcomm SA8155-ADP development
> >> board. Main motivation for this series is to allow running
> >> virtualization software on this board and U-Boot is a good way to
> >> break Qualcomm's boot chain at EL2 with more convenient ways for
> >> uploading and running the code. With this patches applied it is
> >> possible to upload and run Xen on this board. KVM probably should work
> >> too.
> >
> > This is really cool! I've experimented with this on SDM845 and SM8250
> > but never really did anything with it... I'd love to take a look at your
> > Xen branch?
> 
> Honestly, there is nothing to look at right now. I just implemented
> early printk serial driver for the qcom, made hacks to the device tree
> and trying to boot Dom0. I already expecting issues with the GPU,
> because it has own SMMU without virtualization support and Xen already
> complains about it. So I had to remove it from the DTS for a time being.
> 

Did you enable all the clocks/power domains/etc for the GPU SMMU? If I
remember correctly it is off by default and all registers read as
zeroes. The SMMU driver could easily get confused about the capabilities
of the SMMU (e.g. the stage 2/virtualization support) if all the ID
registers read as zeroes.

Thanks,
Stephan