Add a system timer driver for Realtek SoCs.
This driver registers the 1 MHz global hardware counter on Realtek
platforms as a clock event device. Since this hardware counter starts
counting automatically after SoC power-on, no clock initialization is
required. Because the counter does not stop or get affected by CPU power
down, and it supports oneshot mode, it is typically used as a tick
broadcast timer.
Signed-off-by: Hao-Wen Ting <haowen.ting@realtek.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251126060110.198330-3-haowen.ting@realtek.com
am43xx has a clock tree where the global timer clock is an indirect child
of the CPU clock used for frequency scaling:
dpll_mpu_ck -- CPU/cpufreq
|
v
dpll_mpu_m2_ck -- divider
|
v
mpu_periphclk -- fixed divider by 2 used for global timer
When CPU frequency changes, the global timer's clock notifier rejects
the change because the hardcoded prescaler (1 or 2) cannot accommodate
the frequency range across all CPU OPPs (300, 600, 720, 800, 1000 MHz).
Add platform-specific prescaler auto-detection to solve this issue:
- am43xx: prescaler = 50 (calculated as initial_freq/GCD of all OPP
freqs) This allows the timer to work across all CPU frequencies after
the fixed divider by 2. Tested on am4372-idk-evm.
- zynq-7000: prescaler = 2 (preserves previous Kconfig default)
- Other platforms: prescaler = 1 (previous default)
The Kconfig option now defaults to 0 (auto-detection) but can still
override the auto-detected value when set to a non-zero value,
preserving existing customization workflows.
Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Tested-by: Kevin Hilman <khilman@baylibre.com>
Tested-by: Patrice Chotard <patrice.chotard@foss.st.com>
Tested-by: Judith Mendez <jm@ti.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20250819-topic-am43-arm-global-timer-v6-16-v2-1-6d082e2a5161@baylibre.com
Introduce a clocksource driver for the so-called high-precision timer (HPT)
in the EcoNet EN751221 and EN751627 MIPS SoCs.
It's a 32 bit upward-counting one-shot timer which relies on the crystal so it
is unaffected by CPU power mode. On MIPS 34K devices (single core) there is
one timer, and on 1004K devices (dual core) there are two.
Each timer has two sets of count/compare registers so that there is one for
each of the VPEs on the core. Because each core has 2 VPEs, register selection
takes the CPU number / 2 for the timer corrisponding to the core, then CPU
number % 2 for the register corrisponding to the VPE.
These timers use a percpu-devid IRQ to route interrupts to the VPE which set
the event.
Signed-off-by: Caleb James DeLisle <cjd@cjdns.fr>
Link: https://lore.kernel.org/r/20250507134500.390547-3-cjd@cjdns.fr
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Build-testing this driver on arm without CONFIG_OF produces a warning:
drivers/clocksource/timer-atmel-tcb.c:368:34: error: 'atmel_tcb_of_match' defined but not used [-Werror=unused-const-variable=]
368 | static const struct of_device_id atmel_tcb_of_match[] = {
| ^~~~~~~~~~~~~~~~~~
Change the dependency to require CONFIG_OF for build testing to
avoid the warning. Testing remains possible on all architectures
as CONFIG_OF is user-selectable.
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Claudiu Beznea <claudiu.beznea@tuxon.dev>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20250409155313.1096915-1-arnd@kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
STM supports commonly required system and application software timing
functions. STM includes a 32-bit count-up timer and four 32-bit
compare channels with a separate interrupt source for each
channel. The timer is driven by the STM module clock divided by an
8-bit prescale value (1 to 256).
STM has the following features:
• One 32-bit count-up timer with an 8-bit prescaler
• Four 32-bit compare channels
• An independent interrupt source for each channel
• Ability to stop the timer in Debug mode
The s32g platform is declined into two versions, the s32g2 and the
s32g3. The former has a STM block with 8 timers and the latter has 12
timers.
The platform is designed to have one usable STM instance per core on
the system which is composed of 3 x Cortex-M3 + 4 Cortex-A53 for the
s32g2 and 3 x Cortex-M3 + 8 Cortex-A53 for the s32g3.
There is a special STM instance called STM_TS which is dedicated to
the timestamp. The 7th STM instance STM_07 is directly tied to the
STM_TS which means it is not usable as a clockevent.
The driver instantiate each STM described in the device tree as a
clocksource and a clockevent conforming to the reference manual even
if the Linux system does not use all of the clocksource. Each
clockevent will have a cpumask set for a specific CPU.
Given the counter is shared between the clocksource and the
clockevent, the STM module can not be disabled by one or another so
the refcounting mechanism is used to stop the counter when it reaches
zero and to start it when it is one. The suspend and resume relies on
the refcount to stop the module.
As the device tree will have multiple STM entries, the driver can be
probed in parallel with the async option but it is not enabled
yet. However, the driver code takes care of preventing a race by
putting a lock to protect the number of STM instances global variable
which means it is ready to support the option when enough testing will
be done with the underlying time framework.
Cc: Ghennadi Procopciuc <ghennadi.procopciuc@oss.nxp.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: Thomas Fossati <thomas.fossati@linaro.org>
Suggested-by: Ghennadi Procopciuc <ghennadi.procopciuc@nxp.com>
Link: https://lore.kernel.org/r/20250417151623.121109-3-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
System Tick Counter is present on Ralink SoCs RT3352 and MT7620. This
driver has been in 'arch/mips/ralink' directory since the beggining of
Ralink architecture support. However, it can be moved into a more proper
place in 'drivers/clocksource'. Hence add it here adding also support for
compile test targets and reducing LOC in architecture code folder.
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Link: https://lore.kernel.org/r/20241028203643.191268-2-sergio.paracuellos@gmail.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
The sp804 is currently only user selectable if COMPILE_TEST, this was
done by commit dfc82faad7 ("clocksource/drivers/sp804: Add
COMPILE_TEST to CONFIG_ARM_TIMER_SP804") in order to avoid it being
spuriously offered on platforms that won't have the hardware since it's
generally only seen on Arm based platforms. This config is overly
restrictive, while platforms that rely on the SP804 do select it in
their Kconfig there are others such as the Arm fast models which have a
SP804 available but currently unused by Linux. Relax the dependency to
allow it to be user selectable on arm and arm64 to avoid surprises and
in case someone comes up with a use for extra timer hardware.
Fixes: dfc82faad7 ("clocksource/drivers/sp804: Add COMPILE_TEST to CONFIG_ARM_TIMER_SP804")
Reported-by: Ross Burton <ross.burton@arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20241001-arm64-vexpress-sp804-v3-1-0a2d3f7883e4@kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
On MediaTek platforms, CPUXGPT is the source for the AArch64 System
Timer, read through CNTVCT_EL0.
The handling for starting this timer ASAP was introduced in commit
327e93cf9a ("clocksource/drivers/timer-mediatek: Implement CPUXGPT timers")
which description also contains an important full explanation of the
reasons why this driver is necessary and cannot be a module.
In preparation for an eventual conversion of timer-mediatek to a
platform_driver that would be possibly built as a module, split out
the CPUXGPT timers driver to a new timer-mediatek-cpux.c driver.
This commit brings no functional changes.
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Walter Chang <walter.chang@mediatek.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230309103913.116775-1-angelogioacchino.delregno@collabora.com
Pull timer updates from Thomas Gleixner:
"Updates for timekeeping, timers and clockevent/source drivers:
Core:
- Yet another round of improvements to make the clocksource watchdog
more robust:
- Relax the clocksource-watchdog skew criteria to match the NTP
criteria.
- Temporarily skip the watchdog when high memory latencies are
detected which can lead to false-positives.
- Provide an option to enable TSC skew detection even on systems
where TSC is marked as reliable.
Sigh!
- Initialize the restart block in the nanosleep syscalls to be
directed to the no restart function instead of doing a partial
setup on entry.
This prevents an erroneous restart_syscall() invocation from
corrupting user space data. While such a situation is clearly a
user space bug, preventing this is a correctness issue and caters
to the least suprise principle.
- Ignore the hrtimer slack for realtime tasks in schedule_hrtimeout()
to align it with the nanosleep semantics.
Drivers:
- The obligatory new driver bindings for Mediatek, Rockchip and
RISC-V variants.
- Add support for the C3STOP misfeature to the RISC-V timer to handle
the case where the timer stops in deeper idle state.
- Set up a static key in the RISC-V timer correctly before first use.
- The usual small improvements and fixes all over the place"
* tag 'timers-core-2023-02-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (30 commits)
clocksource/drivers/timer-sun4i: Add CLOCK_EVT_FEAT_DYNIRQ
clocksource/drivers/em_sti: Mark driver as non-removable
clocksource/drivers/sh_tmu: Mark driver as non-removable
clocksource/drivers/riscv: Patch riscv_clock_next_event() jump before first use
clocksource/drivers/timer-microchip-pit64b: Add delay timer
clocksource/drivers/timer-microchip-pit64b: Select driver only on ARM
dt-bindings: timer: sifive,clint: add comaptibles for T-Head's C9xx
dt-bindings: timer: mediatek,mtk-timer: add MT8365
clocksource/drivers/riscv: Get rid of clocksource_arch_init() callback
clocksource/drivers/sh_cmt: Mark driver as non-removable
clocksource/drivers/timer-microchip-pit64b: Drop obsolete dependency on COMPILE_TEST
clocksource/drivers/riscv: Increase the clock source rating
clocksource/drivers/timer-riscv: Set CLOCK_EVT_FEAT_C3STOP based on DT
dt-bindings: timer: Add bindings for the RISC-V timer device
RISC-V: time: initialize hrtimer based broadcast clock event device
dt-bindings: timer: rk-timer: Add rktimer for rv1126
time/debug: Fix memory leak with using debugfs_lookup()
clocksource: Enable TSC watchdog checking of HPET and PMTMR only when requested
posix-timers: Use atomic64_try_cmpxchg() in __update_gt_cputime()
clocksource: Verify HPET and PMTMR when TSC unverified
...
Pull clockevent/source updates from Daniel Lezcano:
- Add the missing DT bindings for the MTU nomadik timer (Linus
Walleij)
- Fix grammar typo in the ARM global timer Kconfig option (Randy
Dunlap)
- Add the tegra186 timer and use it on the tegra234 board (Thierry
Reding)
- Add the 'CPUXGPT' CPU timer for Mediatek MT6795 and implement a
workaround to overcome an ATF bug where the timer is not correctly
initialized (AngeloGioacchino Del Regno)
- Rework the suspend/resume approach to enable the feature on the
timer even it is not an active clock and fix a compilation warning
(Claudiu Beznea)
- Add the Add R-Car Gen4 timer support along with the DT bindings
(Wolfram Sang)
- Add compatible for ti,am654-timer to support AM6 SoC (Tony Lindgren)
- Fix Kconfig option to put it back to 'bool' instead of 'tristate'
for the tegra186 (Daniel Lezcano)
- Sort 'family,type' DT bindings for the Renesas timers (Geert
Uytterhoeven)
- Add compatible 'allwinner,sun20i-d1-timer' for Allwinner D1 (Samuel
Holland)
- Remove unnecessary (void*) conversions for sun4i (XU pengfei)
- Remove unnecessary (void*) conversions for sun5i (Li zeming)
Link: https://lore.kernel.org/all/7472984e-f502-5f27-82bf-070127dd85a5@linaro.org
