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

[Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>]

Hi Stephan,

Stephan Gerhold <stephan@gerhold.net> writes:

> 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.

Ah, this is a great idea, thanks. I tried a quick test by enabling only
clocks that are provided by GCC, but looks like I need to enable GPUCC
clocks as well. So I need to write a driver for GPUCC or at least
figure which registers to write with a debugger. I'll try this later.

By the way, do you have any suggestion about my second issue? When Linux
in the Dom0 tries to access UFS, CPU gets a secure interrupt and hangs in
TZ. I had the same exactly behavior when I tried to access EMAC without enabling
clocks and power domains in U-Boot. But Linux should enable all
prerequisites for UFS... I suspect that there is an additional
initialization needs to be done, but I didn't figured it yet.

-- 
WBR, Volodymyr