genirq/irq_sim: Shrink code by using <linux/cleanup.h> helpers

Use the new __free() mechanism to remove all gotos and simplify the error
paths.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20240122124243.44002-5-brgl@bgdev.pl

genirq/irq_sim: Order headers alphabetically

For better readability and maintenance keep headers in alphabetical
order.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240122124243.44002-4-brgl@bgdev.pl

genirq/irq_sim: Remove unused field from struct irq_sim_irq_ctx

The irqnum field is unused. Remove it.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240122124243.44002-3-brgl@bgdev.pl

genirq/irq_sim: Make the irq_work always run in hard irq context

The IRQ simulator uses irq_work to trigger an interrupt. Without the
IRQ_WORK_HARD_IRQ flag the irq_work will be performed in thread context
on PREEMPT_RT. This causes locking errors later in handle_simple_irq()
which expects to be invoked with disabled interrupts.

Triggering individual interrupts in hardirq context should not lead to
unexpected high latencies since this is also what the hardware
controller does. Also it is used as a simulator so...

Use IRQ_WORK_INIT_HARD() to carry out the irq_work in hardirq context on
PREEMPT_RT.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/YnuZBoEVMGwKkLm+@linutronix.de

genirq/irq_sim: Shrink devm_irq_domain_create_sim()

The custom devres structure manages only a single pointer which can
can be achieved by using devm_add_action_or_reset() as well which
makes the code simpler.

[ tglx: Fixed return value handling - found by smatch ]

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210301142659.8971-1-brgl@bgdev.pl

genirq/irq_sim: Fix typos in kernel doc (fnode -> fwnode)

Fix typos in kernel doc, otherwise validation script complains:

.../irq_sim.c:170: warning: Function parameter or member 'fwnode' not described in 'irq_domain_create_sim'
.../irq_sim.c:170: warning: Excess function parameter 'fnode' description in 'irq_domain_create_sim'
.../irq_sim.c:240: warning: Function parameter or member 'fwnode' not described in 'devm_irq_domain_create_sim'
.../irq_sim.c:240: warning: Excess function parameter 'fnode' description in 'devm_irq_domain_create_sim'

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210302161453.28540-1-andriy.shevchenko@linux.intel.com

genirq/irq_sim: Simplify the API

The interrupt simulator API exposes a lot of custom data structures and
functions and doesn't reuse the interfaces already exposed by the irq
subsystem. This patch tries to address it.

We hide all the simulator-related data structures from users and instead
rely on the well-known irq domain. When creating the interrupt simulator
the user receives a pointer to a newly created irq_domain and can use it
to create mappings for simulated interrupts.

It is also possible to pass a handle to fwnode when creating the simulator
domain and retrieve it using irq_find_matching_fwnode().

The irq_sim_fire() function is dropped as well. Instead we implement the
irq_get/set_irqchip_state interface.

We modify the two modules that use the simulator at the same time as
adding these changes in order to reduce the intermediate bloat that would
result when trying to migrate the drivers in separate patches.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> #for IIO
Link: https://lore.kernel.org/r/20200514083901.23445-3-brgl@bgdev.pl

irq/irq_sim: add irq_set_type() callback

Implement the irq_set_type() callback and call irqd_set_trigger_type()
internally so that users interested in the configured trigger type can
later retrieve it using irqd_get_trigger_type(). We only support edge
trigger types.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>

irq/irq_sim: Store multiple interrupt offsets in a bitmap

Two threads can try to fire the irq_sim with different offsets and will
end up fighting for the irq_work asignment. Thomas Gleixner suggested a
solution based on a bitfield where we set a bit for every offset
associated with an interrupt that should be fired and then iterate over
all set bits in the interrupt handler.

This is a slightly modified solution using a bitmap so that we don't
impose a limit on the number of interrupts one can allocate with
irq_sim.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

genirq/irq_sim: Remove the license boilerplate

There is the SPDX license identifier now in the irq simulator. Remove the
license boilerplate.

While at it: update the copyright notice, since I did some changes in 2018.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20180426200747.8344-1-brgl@bgdev.pl

genirq: Add missing SPDX identifiers

Add SPDX identifiers to files

- which contain an explicit license boiler plate or reference

- which do not contain a license reference and were not updated in the
initial SPDX conversion because the license was deduced by the scanners
via EXPORT_SYMBOL_GPL as GPL2.0 only.

[ tglx: Moved adding identifiers from the patch which removes the
references/boilerplate ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Link: https://lkml.kernel.org/r/20180314212030.668321222@linutronix.de

genirq/irq_sim: Return the base of the irq range from irq_sim_init()

Returning the base of the allocated interrupt range from irq_sim_init() and
devm_irq_sim_init() allows users to handle the logic of associating irq
numbers with any other driver-specific resources without having to use
irq_sim_irqnum().

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Link: https://lkml.kernel.org/r/20180304121018.640-4-brgl@bgdev.pl

genirq/irq_sim: Check the return value of irq_sim_init() for error codes

As discussed with Marc Zyngier: irq_sim_init() and its devres variant
should return the base of the allocated interrupt range on success rather
than 0.

Make devm_irq_sim_init() check for an error code. This is a preparatory
change for modifying irq_sim_init() itself.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Link: https://lkml.kernel.org/r/20180304121018.640-3-brgl@bgdev.pl

genirq/irq_sim: Explicitly include slab.h

kfree() is used in the irq_sim code but slab.h is pulled in indirectly via
irq.h. Include it explicitly.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Link: https://lkml.kernel.org/r/20180304121018.640-2-brgl@bgdev.pl

genirq/irq_sim: Add a devres variant of irq_sim_init()

Add a resource managed version of irq_sim_init(). This can be
conveniently used in device drivers.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-doc@vger.kernel.org
Cc: linux-gpio@vger.kernel.org
Cc: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
Cc: Jonathan Cameron <jic23@kernel.org>
Link: http://lkml.kernel.org/r/20170814145318.6495-3-brgl@bgdev.pl
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

genirq/irq_sim: Add a simple interrupt simulator framework

Implement a simple, irq_work-based framework for simulating
interrupts. Currently the API exposes routines for initializing and
deinitializing the simulator object, enqueueing the interrupts and
retrieving the allocated interrupt numbers based on the offset of the
dummy interrupt in the simulator struct.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-doc@vger.kernel.org
Cc: linux-gpio@vger.kernel.org
Cc: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
Cc: Jonathan Cameron <jic23@kernel.org>
Link: http://lkml.kernel.org/r/20170814145318.6495-2-brgl@bgdev.pl
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>