[PATCH 0/2] clocksource/drivers/arm_arch_timer_mmio: Restore support for early init

[Stephan Gerhold]

Jack reported a regression for some single-core Qualcomm platforms (e.g.
MDM9625, MDM9607) that no longer boot because no timers can be found during
early boot [1]. These platforms rely on an obscure timer setup where the
global Arm MMIO timer (arm,armv7-timer-mem) is used as the only available
timer for the CPU. This setup used to work fine until commit 0f67b56d84b4
("clocksource/drivers/arm_arch_timer_mmio: Switch over to standalone
driver") when the early timer initialization using TIMER_OF_DECLARE() was
removed when moving to the standalone MMIO driver.

There doesn't seem to be any other usable CPU timer on those platforms, so
this series restores the early timer support using TIMER_OF_DECLARE()
inside the new standalone arm_arch_timer_mmio driver. This is pretty ugly,
but I could not think of a better solution so far. I tried to keep the
ugliness for the two probe paths as limited as possible. :-)

If someone has a better idea how to solve this, I would be happy to try it.

[1]: https://lore.kernel.org/r/46A20F89-E208-4091-8B6E-B5C38BF82B42@jackmatthe.ws/

Signed-off-by: Stephan Gerhold <stephan.gerhold at linaro.org>
---
Stephan Gerhold (2):
      clocksource/drivers/arm_arch_timer_mmio: Refactor for early init
      clocksource/drivers/arm_arch_timer_mmio: Restore support for early init

 drivers/clocksource/arm_arch_timer_mmio.c | 180 ++++++++++++++++++++----------
 1 file changed, 123 insertions(+), 57 deletions(-)
---
base-commit: 49e02880ec0a8c378e811bc9d85da188d7c6204c
change-id: 20260609-arm-arch-timer-mmio-early-de97155938e4

Best regards,
--  
Stephan Gerhold <stephan.gerhold at linaro.org>