kernel/linux.git/drivers/counter/interrupt-cnt.c, branch v6.12.80

counter: interrupt-cnt: Drop IRQF_NO_THREAD flag

2026-01-17T15:31:16+00:00

commit 23f9485510c338476b9735d516c1d4aacb810d46 upstream. An IRQ handler can either be IRQF_NO_THREAD or acquire spinlock_t, as CONFIG_PROVE_RAW_LOCK_NESTING warns: ============================= [ BUG: Invalid wait context ] 6.18.0-rc1+git... #1 ----------------------------- some-user-space-process/1251 is trying to lock: (&counter->events_list_lock){....}-{3:3}, at: counter_push_event [counter] other info that might help us debug this: context-{2:2} no locks held by some-user-space-process/.... stack backtrace: CPU: 0 UID: 0 PID: 1251 Comm: some-user-space-process 6.18.0-rc1+git... #1 PREEMPT Call trace: show_stack (C) dump_stack_lvl dump_stack __lock_acquire lock_acquire _raw_spin_lock_irqsave counter_push_event [counter] interrupt_cnt_isr [interrupt_cnt] __handle_irq_event_percpu handle_irq_event handle_simple_irq handle_irq_desc generic_handle_domain_irq gpio_irq_handler handle_irq_desc generic_handle_domain_irq gic_handle_irq call_on_irq_stack do_interrupt_handler el0_interrupt __el0_irq_handler_common el0t_64_irq_handler el0t_64_irq ... and Sebastian correctly points out. Remove IRQF_NO_THREAD as an alternative to switching to raw_spinlock_t, because the latter would limit all potential nested locks to raw_spinlock_t only. Cc: Sebastian Andrzej Siewior Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20251117151314.xwLAZrWY@linutronix.de/ Fixes: a55ebd47f21f ("counter: add IRQ or GPIO based counter") Signed-off-by: Alexander Sverdlin Reviewed-by: Sebastian Andrzej Siewior Reviewed-by: Oleksij Rempel Link: https://lore.kernel.org/r/20251118083603.778626-1-alexander.sverdlin@siemens.com Signed-off-by: William Breathitt Gray Signed-off-by: Greg Kroah-Hartman

counter: interrupt-cnt: Protect enable/disable OPs with mutex

2025-06-19T13:32:12+00:00

[ Upstream commit 7351312632e831e51383f48957d47712fae791ef ] Enable/disable seems to be racy on SMP, consider the following scenario: CPU0 CPU1 interrupt_cnt_enable_write(true) { if (priv->enabled == enable) return 0; if (enable) { priv->enabled = true; interrupt_cnt_enable_write(false) { if (priv->enabled == enable) return 0; if (enable) { priv->enabled = true; enable_irq(priv->irq); } else { disable_irq(priv->irq) priv->enabled = false; } enable_irq(priv->irq); } else { disable_irq(priv->irq); priv->enabled = false; } The above would result in priv->enabled == false, but IRQ left enabled. Protect both write (above race) and read (to propagate the value on SMP) callbacks with a mutex. Signed-off-by: Alexander Sverdlin Fixes: a55ebd47f21f ("counter: add IRQ or GPIO based counter") Acked-by: Oleksij Rempel Link: https://lore.kernel.org/r/20250331163642.2382651-1-alexander.sverdlin@siemens.com Signed-off-by: William Breathitt Gray Signed-off-by: Sasha Levin

counter: interrupt-cnt: Implement watch_validate callback

2022-09-30T12:32:35+00:00

The interrupt-cnt counter driver only pushes one type of event on only one channel: COUNTER_EVENT_CHANGE_OF_STATE on channel 0. The interrupt_cnt_watch_validate() watch_valid callback is implemented to ensure watch configurations are valid for this driver. Cc: Oleksij Rempel Cc: Pengutronix Kernel Team Link: https://lore.kernel.org/r/20220815225058.144203-1-william.gray@linaro.org/ Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/c50b5eede7d3f523de8dc3937dc44680f2773e1d.1664318353.git.william.gray@linaro.org Signed-off-by: Greg Kroah-Hartman

counter: Move symbols into COUNTER namespace

2022-09-30T12:32:35+00:00

Counter subsystem symbols are only relevant to counter drivers. A COUNTER namespace is created to control the availability of these symbols to modules that import this namespace explicitly. Cc: Patrick Havelange Cc: Jarkko Nikula Cc: Oleksij Rempel Cc: Pengutronix Kernel Team Cc: Kamel Bouhara Cc: Fabrice Gasnier Cc: Maxime Coquelin Cc: Alexandre Torgue Acked-by: David Lechner Reviewed-by: Jonathan Cameron Link: https://lore.kernel.org/r/20220815220321.74161-1-william.gray@linaro.org/ Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/8a756df96c24946547a7ece5caa5f654809c5e7f.1664318353.git.william.gray@linaro.org Signed-off-by: Greg Kroah-Hartman

counter: interrupt-cnt: add counter_push_event()

2022-03-18T13:04:30+00:00

Add counter_push_event() to notify user space about new pulses Link: https://lore.kernel.org/r/20220203135727.2374052-3-o.rempel@pengutronix.de Signed-off-by: Oleksij Rempel Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/9da3460113b5092e8658e12f23578567aab7cc5f.1647373009.git.vilhelm.gray@gmail.com Signed-off-by: Greg Kroah-Hartman

counter: interrupt-cnt: Convert to new counter registration

2021-12-30T16:44:07+00:00

This fixes device lifetime issues where it was possible to free a live struct device. Fixes: a55ebd47f21f ("counter: add IRQ or GPIO based counter") Reviewed-by: Jonathan Cameron Acked-by: William Breathitt Gray Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20211230150300.72196-17-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman

counter: interrupt-cnt: Convert to counter_priv() wrapper

2021-12-30T16:44:06+00:00

This is a straight forward conversion to the new counter_priv() wrapper. Acked-by: Jonathan Cameron Acked-by: William Breathitt Gray Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20211230150300.72196-7-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman

counter: Internalize sysfs interface code

2021-10-17T09:52:58+00:00

This is a reimplementation of the Generic Counter driver interface. There are no modifications to the Counter subsystem userspace interface, so existing userspace applications should continue to run seamlessly. The purpose of this patch is to internalize the sysfs interface code among the various counter drivers into a shared module. Counter drivers pass and take data natively (i.e. u8, u64, etc.) and the shared counter module handles the translation between the sysfs interface and the device drivers. This guarantees a standard userspace interface for all counter drivers, and helps generalize the Generic Counter driver ABI in order to support the Generic Counter chrdev interface (introduced in a subsequent patch) without significant changes to the existing counter drivers. Note, Counter device registration is the same as before: drivers populate a struct counter_device with components and callbacks, then pass the structure to the devm_counter_register function. However, what's different now is how the Counter subsystem code handles this registration internally. Whereas before callbacks would interact directly with sysfs data, this interaction is now abstracted and instead callbacks interact with native C data types. The counter_comp structure forms the basis for Counter extensions. The counter-sysfs.c file contains the code to parse through the counter_device structure and register the requested components and extensions. Attributes are created and populated based on type, with respective translation functions to handle the mapping between sysfs and the counter driver callbacks. The translation performed for each attribute is straightforward: the attribute type and data is parsed from the counter_attribute structure, the respective counter driver read/write callback is called, and sysfs I/O is handled before or after the driver read/write function is called. Cc: Jarkko Nikula Cc: Patrick Havelange Cc: Kamel Bouhara Cc: Maxime Coquelin Cc: Alexandre Torgue Cc: Dan Carpenter Acked-by: Syed Nayyar Waris Reviewed-by: David Lechner Tested-by: David Lechner Signed-off-by: William Breathitt Gray Reviewed-by: Fabrice Gasnier # for stm32 Link: https://lore.kernel.org/r/c68b4a1ffb195c1a2f65e8dd5ad7b7c14e79c6ef.1630031207.git.vilhelm.gray@gmail.com Signed-off-by: Jonathan Cameron

counter: Rename counter_count_function to counter_function

2021-08-09T19:17:36+00:00

The phrase "Counter Count function" is verbose and unintentionally implies that function is a Count extension. This patch adjusts the Counter subsystem code to use the more direct "Counter function" phrase to make the intent of this code clearer. Cc: Jarkko Nikula Cc: Patrick Havelange Cc: Oleksij Rempel Cc: Kamel Bouhara Cc: Maxime Coquelin Cc: Alexandre Torgue Cc: David Lechner Acked-by: Syed Nayyar Waris Reviewed-by: Fabrice Gasnier Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/8268c54d6f42075a19bb08151a37831e22652499.1627990337.git.vilhelm.gray@gmail.com Signed-off-by: Jonathan Cameron

counter: Rename counter_signal_value to counter_signal_level

2021-08-09T19:17:36+00:00

Signal values will always be levels so let's be explicit it about it to make the intent of the code clear. Cc: Oleksij Rempel Cc: Kamel Bouhara Acked-by: Syed Nayyar Waris Reviewed-by: David Lechner Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/3f17010abe2415859cea9a5fddabd3c97f635ff5.1627990337.git.vilhelm.gray@gmail.com Signed-off-by: Jonathan Cameron