[PATCH v2 0/6] irq/irq_sim: try to improve the API

[Bartosz Golaszewski <brgl@bgdev.pl>]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

This is my second take at improving the interrupt simulator interface.
I marked it as v2 but it actually takes a completely different approach.

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 series tries to address it.

First, we make irq_domain_reset_irq_data() available to non-V2 domain API
users - that'll be used in the subsequent patch. Next we overhaul the
public interfaces - we hide all specific data structures and instead
rely on the irq_domain struct and virtual interrupt numberspace.

Next four patches simplify the interface even more, but since the change
may be a bit more controversial due to modification of the irq_domain
I decided to split them out of the second patch.

In patch 3/6 we're adding a new callback to irq_domain_ops that is called
right before all the other code in irq_domain_remove(). Next we use it to
remove the simulator-specific cleanup function from irq_sim.h - users now
can simply use the regular irq_domain_remove().

Last two patches show that the new callback isn't limited to the interrupt
simulator and can be used to shrink code in real driver too. We introduce
a new helper for a common use case of disposing of all mappings before
removing the irq_domain and use it in the keystone irqchip driver.

The end effect is that we limit the interrupt simulator API to two
functions (plus one device managed variant) and zero new structures.

v1: https://lkml.org/lkml/2019/8/12/558

v1 -> v2:
- instead of just making the new data structures opaque for users, remove
  them entirely in favor of irq_domain
- call irq_set_handler() & irq_domain_reset_irq_data() when unmapping
  the simulated interrupt
- fix a memory leak in error path
- make it possible to use irq_find_matching_fwnode() with the simulator
  domain
- correctly use irq_create_mapping() and irq_find_mapping(): only use the
  former at init-time and the latter at interrupt-time

Bartosz Golaszewski (6):
  irq: make irq_domain_reset_irq_data() available even for non-V2 users
  irq/irq_sim: simplify the API
  irq/domain: add a new callback to domain ops
  irq/irq_sim: remove irq_domain_remove_sim()
  irq/domain: provide irq_domain_dispose_mappings() helper
  irqchip: keystone: use irq_domain_dispose_mappings()

 drivers/gpio/gpio-mockup.c          |  47 ++++--
 drivers/iio/dummy/iio_dummy_evgen.c |  32 ++--
 drivers/irqchip/irq-keystone.c      |   5 +-
 include/linux/irq_sim.h             |  33 ++--
 include/linux/irqdomain.h           |   9 +-
 kernel/irq/Kconfig                  |   1 +
 kernel/irq/irq_sim.c                | 225 ++++++++++++++++------------
 kernel/irq/irqdomain.c              |  44 ++++--
 8 files changed, 238 insertions(+), 158 deletions(-)

-- 
2.25.0