irq: add irq_domain translation infrastructure

This patch adds irq_domain infrastructure for translating from
hardware irq numbers to linux irqs.  This is particularly important
for architectures adding device tree support because the current
implementation (excluding PowerPC and SPARC) cannot handle
translation for more than a single interrupt controller.  irq_domain
supports device tree translation for any number of interrupt
controllers.

This patch converts x86, Microblaze, ARM and MIPS to use irq_domain
for device tree irq translation.  x86 is untested beyond compiling it,
irq_domain is enabled for MIPS and Microblaze, but the old behaviour is
preserved until the core code is modified to actually register an
irq_domain yet.  On ARM it works and is required for much of the new
ARM device tree board support.

PowerPC has /not/ been converted to use this new infrastructure.  It
is still missing some features before it can replace the virq
infrastructure already in powerpc (see documentation on
irq_domain_map/unmap for details).  Followup patches will add the
missing pieces and migrate PowerPC to use irq_domain.

SPARC has its own method of managing interrupts from the device tree
and is unaffected by this change.

Acked-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
dt/irq: add irq_domain_generate_simple() helper

irq_domain_generate_simple() is an easy way to generate an irq translation
domain for simple irq controllers.  It assumes a flat 1:1 mapping from
hardware irq number to an offset of the first linux irq number assigned
to the controller

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
irq: Add declaration of irq_domain_simple_ops to irqdomain.h

irq_domain_simple_ops is exported, but is not declared in irqdomain.h,
so add it.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: marc.zyngier@arm.com
Cc: thomas.abraham@linaro.org
Cc: jamie@jamieiles.com
Cc: b-cousson@ti.com
Cc: shawn.guo@linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: devicetree-discuss@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1316017900-19918-2-git-send-email-robherring2@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
irq: support domains with non-zero hwirq base

Interrupt controllers can have non-zero starting value for h/w irq numbers.
Adding support in irq_domain allows the domain hwirq numbering to match
the interrupt controllers' numbering.

As this makes looping over irqs for a domain more complicated, add loop
iterators to iterate over all hwirqs and irqs for a domain.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Reviewed-by: Jamie Iles <jamie@jamieiles.com>
Tested-by: Thomas Abraham <thomas.abraham@linaro.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
ARM: 7235/1: irqdomain: export irq_domain_simple_ops for !CONFIG_OF

irqdomain support is used in interrupt controller drivers that may not
have device tree support but only need the basic HW->Linux irq
translation.  Rather than having each of these implement their own IRQ
domain, allow them to use the simple ops.

Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rob Herring <robherring2@gmail.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
irq_domain: Create common xlate functions that device drivers can use

Rather than having each interrupt controller driver creating its own barely
unique .xlate function for irq_domain, create a library of translators which
any driver can use directly.

v5: - Remove irq_domain_xlate_pci().  It was incorrect.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Mark Salter <msalter@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Milton Miller <miltonm@bga.com>
Tested-by: Olof Johansson <olof@lixom.net>
irq_domain: Centralize definition of irq_dispose_mapping()

Several architectures define their own empty irq_dispose_mapping().  Since
the irq_domain code is centralized now, there is little need to do so.  This
patch removes them and creates a new empty copy when !CONFIG_IRQ_DOMAIN is
selected.

The patch also means that IRQ_DOMAIN becomes selectable on all architectures.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: sparclinux@vger.kernel.org
Cc: linux@lists.openrisc.net