irq/gpio: ixp4xx: Drop boardfile probe path

The boardfiles for IXP4xx have been deleted. Delete all the
quirks and code dealing with that boot path and rely solely on
device tree boot.

Fix some missing static keywords that the kernel test robot
was complaining about while we're at it.

Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

irq: remove handle_domain_{irq,nmi}()

Now that entry code handles IRQ entry (including setting the IRQ regs)
before calling irqchip code, irqchip code can safely call
generic_handle_domain_irq(), and there's no functional reason for it to
call handle_domain_irq().

Let's cement this split of responsibility and remove handle_domain_irq()
entirely, updating irqchip drivers to call generic_handle_domain_irq().

For consistency, handle_domain_nmi() is similarly removed and replaced
with a generic_handle_domain_nmi() function which also does not perform
any entry logic.

Previously handle_domain_{irq,nmi}() had a WARN_ON() which would fire
when they were called in an inappropriate context. So that we can
identify similar issues going forward, similar WARN_ON_ONCE() logic is
added to the generic_handle_*() functions, and comments are updated for
clarity and consistency.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>

irqchip/ixp4xx: Register the base PA instead of its VA in fwnode

Do not expose the base VA (it appears in debugfs). Instead,
record the PA, which at least can be used to precisely identify
the associated irqchip and domain.

Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <maz@kernel.org>

ARM: ixp4xx: mark ixp4xx_irq_setup as __init

Kbuild complains about ixp4xx_irq_setup not being __init
itself in some configurations:

WARNING: vmlinux.o(.text+0x85bae4): Section mismatch in reference from the function ixp4xx_irq_setup() to the function .init.text:set_handle_irq()
The function ixp4xx_irq_setup() references
the function __init set_handle_irq().
This is often because ixp4xx_irq_setup lacks a __init
annotation or the annotation of set_handle_irq is wrong.

I suspect it normally gets inlined, so we get no such warning,
but clang makes this obvious when the function is left out
of line.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Olof Johansson <olof@lixom.net>

irqchip: ixp4xx: Add OF initialization support

This adds support for probing and settin up the IXP4xx
irqchip from device tree.

Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

irqchip: Add driver for IXP4xx

The IXP4xx (arch/arm/mach-ixp4xx) is an old Intel XScale
platform that has very wide deployment and use.

As part of modernizing the platform, we need to implement a
proper irqchip in the irqchip subsystem.

The IXP4xx irqchip is tightly jotted together with the GPIO
controller, and whereas in the past we would deal with this
complex logic by adding necessarily different code, we can
nowadays modernize it using a hierarchical irqchip.

The actual IXP4 irqchip is a simple active low level IRQ
controller, whereas the GPIO functionality resides in a
different memory area and adds edge trigger support for
the interrupts.

The interrupts from GPIO lines 0..12 are 1:1 mapped to
a fixed set of hardware IRQs on this IRQchip, so we
expect the child GPIO interrupt controller to go in and
allocate descriptors for these interrupts.

For the other interrupts, as we do not yet have DT
support for this platform, we create a linear irqdomain
and then go in and allocate the IRQs that the legacy
boards use. This code will be removed on the DT probe
path when we add DT support to the platform.

We add some translation code for supporting DT
translations for the fwnodes, but we leave most of that
for later.

Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>