of_irq_init will scan the devicetree for matching interrupt controller
nodes. Then it calls an initialization function for each found controller
in the proper order with parent nodes initialized before child nodes.

Based on initial pseudo code from Grant Likely.

Changes in v4:
- Drop unnecessary empty list check
- Be more verbose on errors
- Simplify "if (!desc) WARN_ON(1)" to "if (WARN_ON(!desc))"

Changes in v3:
- add missing kfree's found by Jamie
- Implement Grant's comments to simplify the init loop
- fix function comments

Changes in v2:
- Complete re-write of list searching code from Grant Likely
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Reviewed-by: NJamie Iles <jamie@jamieiles.com>
Tested-by: NThomas Abraham <thomas.abraham@linaro.org>
Acked-by: NGrant Likely <grant.likely@secretlab.ca>

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: NRalf Baechle <ralf@linux-mips.org>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

We have platform code that needs to find a node's interrupt parent, so
export of_irq_find_parent() so we can use it.
Signed-off-by: NMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

It works on current architectures simply because asm/prom.h includes
it, but it broke when x86 turned on CONFIG_OF.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

Instead of referencing NO_IRQ in platform.c, define some helper functions
in irq.c to call instead from platform.c.  Keep NO_IRQ usage local to
irq.c, and define NO_IRQ if not defined in headers.
Signed-off-by: NAndres Salomon <dilinger@queued.net>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

Merge common irq mapping code between PowerPC and Microblaze.

This patch merges of_irq_find_parent(), of_irq_map_raw() and
of_irq_map_one().  The functions are dependent on one another, so all
three are merged in a single patch.  Other than cosmetic difference
(ie. DBG() vs. pr_debug()), the implementations are identical.

of_irq_to_resource() is also merged, but in this case the
implementations are different.  This patch drops the microblaze version
and uses the powerpc implementation unchanged.  The microblaze version
essentially open-coded irq_of_parse_and_map() which it does not need
to do.  Therefore the powerpc version is safe to adopt.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
CC: Michal Simek <monstr@monstr.eu>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Stephen Rothwell <sfr@canb.auug.org.au>

Merge common code between PowerPC and Microblaze.  SPARC implements
irq_of_parse_and_map(), but the implementation is different, so it
does not use this code.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Jeremy Kerr <jeremy.kerr@canonical.com>