This reverts commit dc937280.

As requested by Ben Herrenschmidt:
  "This breaks some powerpc platforms at least.  The practice of having
   a node provide an explicit "interrupt-parent" property pointing to
   itself is an old trick that we've used in the past to allow a
   device-node to have interrupts routed to different controllers.

   In that case, the node also contains an interrupt-map, so the node is
   its own parent, the interrupt resolution hits the map, which then can
   route each individual interrupt to a different parent."

Grant says:
  "Ah, nuts, yes that is broken then.  Yes, please revert the commit and
   Rob & I will come up with a better solution.

   Rob, I think it can be done by explicitly checking for np ==
   desc->interrupt_parent in of_irq_init() instead of relying on
   of_irq_find_parent() returning NULL."
Requested-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: NGrant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: devicetree-discuss@lists.ozlabs.org
Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: Tanmay Inamdar <tinamdar@apm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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>

An interrupt controller may often implicitly inherit itself from a parent
node when in fact the controller is the interrupt root controller. Guard
against the case of child == parent and return NULL in this case.

This can also be fixed by adding an explicit "interrupt-parent;" to a root
interrupt controller node.

Based on code from Grant Likely.
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Cc: Grant 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>

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>

This patch fixes some instances where interrupt specifiers are
dereferenced directly instead of doing a be32_to_cpu() conversion first.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

The flat tree code wasn't fixing the endianness on phandle values when
unflattening the tree, and the code in drivers/of wasn't always doing a
be32_to_cpu before trying to dereference the phandle values.  This patch
fixes them.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

Resource names appear in human readable output, so when extracting IRQ
and address resources from a device tree node, use the full node name
to give proper context in places like /proc/iomem.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
CC: Michal Simek <monstr@monstr.eu>
CC: Stephen Rothwell <sfr@canb.auug.org.au>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: microblaze-uclinux@itee.uq.edu.au
CC: linuxppc-dev@ozlabs.org

Fix some endian issues in the irq mapping OF code.
Signed-off-by: NRob Herring <r.herring@freescale.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
CC: Michal Simek <monstr@monstr.eu>
CC: Wolfram Sang <w.sang@pengutronix.de>
CC: Stephen Rothwell <sfr@canb.auug.org.au>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>

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>