[PATCH 0/4] clocksource: Add standalone MMIO ARM arch timer driver
Sudeep Holla
sudeep.holla at arm.com
Wed Aug 13 03:55:48 PDT 2025
+Alexandru
On Thu, Aug 07, 2025 at 05:02:39PM +0100, Marc Zyngier wrote:
> For the past 10 years, both Mark and I have been lamenting about the
> sorry state of the badly named "arch_timer" driver, and about the way
> the MMIO part is intricately weaved into the system-register part.
>
> The time has finally come to have a stab at it.
>
> This small series simply creates a new timer driver for the MMIO arch
> timer, and only that. It is an actual driver, and not some kludge that
> has to run super early (that's what the per-CPU timers are for). This
> allows, in turn, a pretty large cleanup of the per-CPU driver, though
> there is more to come -- one thing at a time.
>
> As an added bonus, we get a clocksource, which the original code
> didn't provide. Just in case it might be useful. The end-result is far
> more readable, and about 100 lines smaller.
>
(Tested it on Juno R2 and FVP in both DT and ACPI boot)
Tested-by: Sudeep Holla <sudeep.holla at arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla at arm.com>
Alexandru found it useful(avoids some unexpected hang IIUC) in his setup
based on bootwrapper which doesn't initialise MMIO timers.
--
Regards,
Sudeep
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