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: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin 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: Grant 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: Andres Salomon <dilinger@queued.net>
Signed-off-by: Grant 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: Grant 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: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Benjamin 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>