From: Marc Zyngier <maz@kernel.org>
To: linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>,
Hanjun Guo <guohanjun@huawei.com>,
Sudeep Holla <sudeep.holla@arm.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Mark Rutland <mark.rutland@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Steven Price <steven.price@arm.com>
Subject: [PATCH v2 0/4] clocksource: Add standalone MMIO ARM arch timer driver
Date: Thu, 14 Aug 2025 16:46:18 +0100 [thread overview]
Message-ID: <20250814154622.10193-1-maz@kernel.org> (raw)
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 take 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.
Patches on top of 6.17-rc1.
* From v1 [1]:
- Narrow the max delta to something that fits an unsigned long, as
the core code doesn't deal with 64bit quantities on 32bit CPUs.
- Collected RBs and TBs from Sudeep, with thanks.
Marc Zyngier (4):
ACPI: GTDT: Generate platform devices for MMIO timers
clocksource/drivers/arm_arch_timer: Add standalone MMIO driver
clocksource/drivers/arm_arch_timer_mmio: Switch over to standalone
driver
clocksource/drivers/arm_arch_timer_mmio: Add MMIO clocksource
MAINTAINERS | 1 +
drivers/acpi/arm64/gtdt.c | 29 +-
drivers/clocksource/Makefile | 1 +
drivers/clocksource/arm_arch_timer.c | 686 ++--------------------
drivers/clocksource/arm_arch_timer_mmio.c | 440 ++++++++++++++
include/clocksource/arm_arch_timer.h | 5 -
6 files changed, 532 insertions(+), 630 deletions(-)
create mode 100644 drivers/clocksource/arm_arch_timer_mmio.c
--
2.39.2
next reply other threads:[~2025-08-14 15:46 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-14 15:46 Marc Zyngier [this message]
2025-08-14 15:46 ` [PATCH v2 1/4] ACPI: GTDT: Generate platform devices for MMIO timers Marc Zyngier
2025-08-14 15:46 ` [PATCH v2 2/4] clocksource/drivers/arm_arch_timer: Add standalone MMIO driver Marc Zyngier
2025-08-14 15:46 ` [PATCH v2 3/4] clocksource/drivers/arm_arch_timer_mmio: Switch over to standalone driver Marc Zyngier
2025-10-30 16:35 ` Lorenzo Pieralisi
2025-10-30 16:55 ` Marc Zyngier
2025-08-14 15:46 ` [PATCH v2 4/4] clocksource/drivers/arm_arch_timer_mmio: Add MMIO clocksource Marc Zyngier
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