Regression in split ARM MMIO timer driver

[Sudeep Holla]

On Fri, May 08, 2026 at 03:48:14PM -0400, Jack Matthews wrote:
> Hello,
>
> I am working on mainlining an old chip, Qualcomm's MDM9625 modem.
> I had previously booted 6.17-rc3 before putting this project to the side,
> but when I restarted work on 7.0 I was unable to boot. 
> I have bisected this to commit 0f67b56d84b4c49adfd61f19f81f84ec613ab51a
> (https://lore.kernel.org/all/20250814154622.10193-4-maz@kernel.org/) and
> reverting this commit makes the device boot successfully. Unfortunately I do
> not have access to low level debugging such as UART so I have not been able
> to pinpoint exactly what is missing.
> My changes for this chip are all available here in case it is an issue of my
> own doing: https://github.com/jackmthws/linux/commits/mdm9625-latest/.

Looking briefly into the DTS file, I couldn't find the sysreg based arch
timer node in the DT. It could be just an overlook unless there is some
issue with it that it's not added. After the above mentioned commit, the
MMIO timer gets initialised bit late in the boot and could be the reason
for boot failure. Unless you have intentionally not added it, I would
suggest to add it and try.

-- 
Regards,
Sudeep