The device tree property "msi-map" specifies how to create the PCI
requester id used in some MSI controllers.  Add a new function
of_msi_map_rid() that finds the msi-map property and applies its
translation to a given requester id.
Reviewed-by: NMarc Zyngier <marc.zyngier@arm.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NDavid Daney <david.daney@cavium.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Similarly to of_get_irq(), let's export of_irq_get_byname(), so if a bus core
can be compiled as a module (such as I2C) it can have access to the symbol.
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

As for PCI, we're able to populate the msi_domain field at probe time,
provided that the device tree has an "msi-parent" property.
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: Yijing Wang <wangyijing@huawei.com>
Cc: Ma Jun <majun258@huawei.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Duc Dang <dhdang@apm.com>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1438091186-10244-9-git-send-email-marc.zyngier@arm.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Now CONFIG_OF can be enabled on sh:

    drivers/of/irq.c:472:8: error: redefinition of 'struct intc_desc'
    include/linux/sh_intc.h:109:8: note: originally defined here

As "intc_desc" is used all over the place in sh platform code, while
drivers/of/irq.c has a local definition used in a single function,
rename the latter by prefixing it with "of_".
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

of_irq_parse_raw() needs to return the correct interrupt controller
node when an interrupt-map property doesn't exist.

It allows of_irq_parse_raw() to return the node pointer of the interrupt
controller, rather than the parent bus. This allows ics_rtas_host_match()
to detect that the controller is a legacy 8259 and avoid using xics.
This avoids an RTAS assertion/crash during early kernel bootstrapping.
Signed-off-by: NJeremy Linton <lintonrjeremy@gmail.com>
Reviewed-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

The error code paths that require cleanup use a goto to jump to the
cleanup code and return an error code. However, the error code variable
res, which is initialized to -EINVAL when declared, is then overwritten
with the return value of of_parse_phandle_with_args(), and reused as the
return code from of_irq_parse_one(). This leads to an undetermined error
being returned instead of the expected -EINVAL value. Fix it.
Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Cc: stable@vger.kernel.org # 3.13+
Signed-off-by: NRob Herring <robh@kernel.org>

The function will be used by the I2C core which can be compiled as a
module.
Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: NRob Herring <robh@kernel.org>
Acked-by: NGrant Likely <grant.likely@linaro.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

In case the Device Tree blob passed by the boot agent supplies both an
'interrupts-extended' and an 'interrupts' property in order to allow for
older kernels to be usable, prefer the new-style 'interrupts-extended'
property which conveys a lot more information.

This allows us to have bootloaders willingly maintaining backwards
compatibility with older kernels without entirely deprecating the
'interrupts' property.

Update the bindings documentation to describe a situation where both the
'interrupts-extended' and the 'interrupts' property are present, and
which one takes precedence over the other.

Cc: stable@vger.kernel.org # 3.13+
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

The commit 9ec36caf
"of/irq: do irq resolution in platform_get_irq" from Rob Herring -
moves resolving of the interrupt resources in platform_get_irq().
But this solution isn't complete because platform_get_irq_byname()
need to be modified the same way.

Hence, fix it by adding interrupt resolution code at the
platform_get_irq_byname() function too.

Cc: Russell King <linux@arm.linux.org.uk>
Cc: Rob Herring <robh@kernel.org>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

Currently we get the following kind of errors if we try to use interrupt
phandles to irqchips that have not yet initialized:

irq: no irq domain found for /ocp/pinmux@48002030 !
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at drivers/of/platform.c:171 of_device_alloc+0x144/0x184()
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.12.0-00038-g42a9708 #1012
(show_stack+0x14/0x1c)
(dump_stack+0x6c/0xa0)
(warn_slowpath_common+0x64/0x84)
(warn_slowpath_null+0x1c/0x24)
(of_device_alloc+0x144/0x184)
(of_platform_device_create_pdata+0x44/0x9c)
(of_platform_bus_create+0xd0/0x170)
(of_platform_bus_create+0x12c/0x170)
(of_platform_populate+0x60/0x98)

This is because we're wrongly trying to populate resources that are not
yet available. It's perfectly valid to create irqchips dynamically, so
let's fix up the issue by resolving the interrupt resources when
platform_get_irq is called.

And then we also need to accept the fact that some irqdomains do not
exist that early on, and only get initialized later on. So we can
make the current WARN_ON into just into a pr_debug().

We still attempt to populate irq resources when we create the devices.
This allows current drivers which don't use platform_get_irq to continue
to function. Once all drivers are fixed, this code can be removed.
Suggested-by: NRussell King <linux@arm.linux.org.uk>
Signed-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NTony Lindgren <tony@atomide.com>
Tested-by: NTony Lindgren <tony@atomide.com>
Cc: stable@vger.kernel.org # v3.10+
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

s/interrupts-names/interrupt-names/g
s/clocks-names/clock-names/g

Some of the binding files and device tree files get this wrong and the
kernel won't be able to pick it up. Fix them up now so that they don't
get widely used.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by : Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

Commit 23616132, "of/irq: Refactor interrupt-map parsing" changed
the refcount on the device_node causing an error in of_node_put():

ERROR: Bad of_node_put() on /pci@800000020000000
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.13.0-rc3-dirty #2
Call Trace:
[c00000003e403500] [c0000000000144fc] .show_stack+0x7c/0x1f0 (unreliable)
[c00000003e4035d0] [c00000000070f250] .dump_stack+0x88/0xb4
[c00000003e403650] [c0000000005e8768] .of_node_release+0xd8/0xf0
[c00000003e4036e0] [c0000000005eeafc] .of_irq_parse_one+0x10c/0x280
[c00000003e4037a0] [c0000000005efd4c] .of_irq_parse_pci+0x3c/0x1d0
[c00000003e403840] [c000000000038240] .pcibios_setup_device+0xa0/0x2e0
[c00000003e403910] [c0000000000398f0] .pcibios_setup_bus_devices+0x60/0xd0
[c00000003e403990] [c00000000003b3a4] .__of_scan_bus+0x1a4/0x2b0
[c00000003e403a80] [c00000000003a62c] .pcibios_scan_phb+0x30c/0x410
[c00000003e403b60] [c0000000009fe430] .pcibios_init+0x7c/0xd4

This patch adjusts the refcount in the walk of the interrupt tree.
When a match is found, there is no need to increase the refcount
on 'out_irq->np' as 'newpar' is already holding a ref. The refcount
balance between 'ipar' and 'newpar' is maintained in the skiplevel:
goto label.

This patch also removes the usage of the device_node variable 'old'
which seems useless after the latest changes.
Signed-off-by: NCédric Le Goater <clg@fr.ibm.com>
Signed-off-by: NRob Herring <robh@kernel.org>

When searching the interrupt map, if a matched parent is disabled, just
ignore it and move on with the search.

This allows for specifying connection of a single device IRQ to
multiple interrupt controllers via the interrupt map schema. This change
allows for selection of the active interrupt controller via the already
existing status = "disabled" mechanism.
Signed-off-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>
Acked-by: NMichal Simek <michal.simek@xilinx.com>
Signed-off-by: NRob Herring <rob.herring@calxeda.com>

When searching the system for interrupt controllers, skip over any
that are explicitly disabled.

This makes interrupt controllers consistent with regular devices,
which can be marked as do-not-probe via the status = "disabled" dts
property.
Signed-off-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>
Acked-by: NMichal Simek <michal.simek@xilinx.com>
Signed-off-by: NRob Herring <rob.herring@calxeda.com>

This patch fixes interrupt-map entry matching code to properly match all
specifier cells with interrupt map entries.
Signed-off-by: NTomasz Figa <t.figa@samsung.com>
Tested-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NRob Herring <rob.herring@calxeda.com>

Commit 23616132, "of/irq: Refactor interrupt-map parsing" introduced
a potential buffer overflow bug because it doesn't do sufficient range
checking on the input data. This patch adds the appropriate checking and
buffer size adjustments. If the bounds are out of range then warn
loudly. MAX_PHANDLE_ARGS should be sufficient. If it is not then the
value can be increased.
Signed-off-by: NGrant Likely <grant.likely@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>

Commit 23616132, "of/irq: Refactor interrupt-map parsing" introduced
a bug. The irq parsing will fail for some nodes that don't have a reg
property. It is fixed by deferring the check for reg until it is
actually needed. Also adjust the testcase data to catch the bug.
Signed-off-by: NGrant Likely <grant.likely@linaro.org>
Tested-by: NStephen Warren <swarren@nvidia.com>
Tested-by: NMing Lei <tom.leiming@gmail.com>
Tested-by: NStephen Warren <swarren@nvidia.com>
Cc: Rob Herring <rob.herring@calxeda.com>

The standard interrupts property in device tree can only handle
interrupts coming from a single interrupt parent. If a device is wired
to multiple interrupt controllers, then it needs to be attached to a
node with an interrupt-map property to demux the interrupt specifiers
which is confusing. It would be a lot easier if there was a form of the
interrupts property that allows for a separate interrupt phandle for
each interrupt specifier.

This patch does exactly that by creating a new interrupts-extended
property which reuses the phandle+arguments pattern used by GPIOs and
other core bindings.
Signed-off-by: NGrant Likely <grant.likely@linaro.org>
Acked-by: NTony Lindgren <tony@atomide.com>
Acked-by: NKumar Gala <galak@codeaurora.org>
[grant.likely: removed versatile platform hunks into separate patch]
Cc: Rob Herring <rob.herring@calxeda.com>

The of_irq_to_resource() helper that is used to implement of_irq_count()
tries to resolve interrupts and in fact creates a mapping for resolved
interrupts. That's pretty heavy lifting for something that claims to
just return the number of interrupts requested by a given device node.

Instead, use the more lightweight of_irq_map_one(), which, despite the
name, doesn't create an actual mapping. Perhaps a better name would be
of_irq_translate_one().
Signed-off-by: NThierry Reding <treding@nvidia.com>
Acked-by: NRob Herring <rob.herring@calxeda.com>
[grant.likely: fixup s/of_irq_map_one/of_irq_parse_one/]
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

It is sometimes useful for debug to get the contents of an
of_phandle_args structure out into the kernel log.
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

All the users of of_irq_parse_raw pass in a raw interrupt specifier from
the device tree and expect it to be returned (possibly modified) in an
of_phandle_args structure. However, the primary function of
of_irq_parse_raw() is to check for translations due to the presence of
one or more interrupt-map properties. The actual placing of the data
into an of_phandle_args structure is trivial. If it is refactored to
accept an of_phandle_args structure directly, then it becomes possible
to consume of_phandle_args from other sources. This is important for an
upcoming patch that allows a device to be connected to more than one
interrupt parent. It also simplifies the code a bit.

The biggest complication with this patch is that the old version works
on the interrupt specifiers in __be32 form, but the of_phandle_args
structure is intended to carry it in the cpu-native version. A bit of
churn was required to make this work. In the end it results in tighter
code, so the churn is worth it.
Signed-off-by: NGrant Likely <grant.likely@linaro.org>
Acked-by: NTony Lindgren <tony@atomide.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>

All the callers of irq_create_of_mapping() pass the contents of a struct
of_phandle_args structure to the function. Since all the callers already
have an of_phandle_args pointer, why not pass it directly to
irq_create_of_mapping()?
Signed-off-by: NGrant Likely <grant.likely@linaro.org>
Acked-by: NMichal Simek <monstr@monstr.eu>
Acked-by: NTony Lindgren <tony@atomide.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>

struct of_irq and struct of_phandle_args are exactly the same structure.
This patch makes the kernel use of_phandle_args everywhere. This in
itself isn't a big deal, but it makes some follow-on patches simpler.
Signed-off-by: NGrant Likely <grant.likely@linaro.org>
Acked-by: NMichal Simek <monstr@monstr.eu>
Acked-by: NTony Lindgren <tony@atomide.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The OF irq handling code has been overloading the term 'map' to refer to
both parsing the data in the device tree and mapping it to the internal
linux irq system. This is probably because the device tree does have the
concept of an 'interrupt-map' function for translating interrupt
references from one node to another, but 'map' is still confusing when
the primary purpose of some of the functions are to parse the DT data.

This patch renames all the of_irq_map_* functions to of_irq_parse_*
which makes it clear that there is a difference between the parsing
phase and the mapping phase. Kernel code can make use of just the
parsing or just the mapping support as needed by the subsystem.

The patch was generated mechanically with a handful of sed commands.
Signed-off-by: NGrant Likely <grant.likely@linaro.org>
Acked-by: NMichal Simek <monstr@monstr.eu>
Acked-by: NTony Lindgren <tony@atomide.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Some drivers might rely on availability of trigger flags in IRQ
resource, for example to configure the hardware for particular interrupt
type. However current code creating IRQ resources from data in device
tree does not configure trigger flags in resulting resources.

This patch tries to solve the problem, based on the fact that
irq_of_parse_and_map() configures the trigger based on DT interrupt
specifier and IRQD_TRIGGER_* flags are consistent with IORESOURCE_IRQ_*,
and we can get correct trigger flags by calling irqd_get_trigger_type()
after mapping the interrupt.
Signed-off-by: NTomasz Figa <tomasz.figa@gmail.com>
[grant.likely: Merged the two assignments to r->flags]
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

Several locations in the of_address and of_irq code dereference the
full_name parameter from a device_node pointer without checking if the
pointer is valid.  This patch switches to use of_node_full_name() which
always checks the pointer.
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

Fix trivial comment typo for irq_of_parse_and_map().
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

It almost does not matter because most users use only the ->start member
of the struct. However if this struct is passed to a platform device
which is then added via platform_device_add() then the ->parent member is
also used.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

list_first_entry() expects the list is not empty, we need to check if list is
empty before calling list_first_entry(). Thus use list_first_entry_or_null()
instead of list_first_entry().
Signed-off-by: NAxel Lin <axel.lin@ingics.com>
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

drivers/of/irq.c:195:57: warning: restricted __be32 degrades to integer
drivers/of/irq.c:196:51: warning: restricted __be32 degrades to integer
drivers/of/irq.c:199:57: warning: restricted __be32 degrades to integer
drivers/of/irq.c:201:58: warning: restricted __be32 degrades to integer
drivers/of/irq.c:470:37: warning: incorrect type in assignment (different modifiers)
drivers/of/irq.c:470:37:    expected int ( *[usertype] irq_init_cb )( ... )
drivers/of/irq.c:470:37:    got void const *const data
drivers/of/irq.c:96:5: error: symbol 'of_irq_map_raw' redeclared with different type (originally declared at include/linux/of_irq.h:61) - incompatible argument 2 (different base types)

drivers/of/of_pci_irq.c:91:40: warning: incorrect type in argument 2 (different base types)
drivers/of/of_pci_irq.c:91:40:    expected unsigned int const [usertype] *intspec
drivers/of/of_pci_irq.c:91:40:    got restricted __be32 *<noident>
drivers/of/of_pci_irq.c:91:53: warning: incorrect type in argument 4 (different base types)
drivers/of/of_pci_irq.c:91:53:    expected unsigned int const [usertype] *addr
drivers/of/of_pci_irq.c:91:53:    got restricted __be32 *<noident>
Signed-off-by: NKim Phillips <kim.phillips@freescale.com>
Signed-off-by: NRob Herring <rob.herring@calxeda.com>

Trivial patch that exports the of_irq_to_resource_table() symbol so that
modules can use it.
Signed-off-by: NJohn Crispin <blogic@openwrt.org>
Signed-off-by: NRob Herring <rob.herring@calxeda.com>

The pattern (np ? np->full_name : "<none>") is rather common in the
kernel, but can also make for quite long lines.  This patch adds a new
inline function, of_node_full_name() so that the test for a valid node
pointer doesn't need to be open coded at all call sites.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NRob Herring <rob.herring@calxeda.com>

The pattern (np ? np->full_name : "<none>") is rather common in the
kernel, but can also make for quite long lines.  This patch adds a new
inline function, of_node_full_name() so that the test for a valid node
pointer doesn't need to be open coded at all call sites.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Thomas Gleixner <tglx@linutronix.de>

Add a interrupts-names property to allow the possibility to provide a name
to any interrupts entries.  If the name is available, use it to name the
resource, otherwise keep the device full name.
Signed-off-by: NBenoit Cousson <b-cousson@ti.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
[grant.likely: use "interrupt-names" and tidy documentation]
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

PPC32/64 defines NO_IRQ to zero, so no problems expected.
ARM defines NO_IRQ to -1, but OF code relies on IRQ domains support,
which returns correct ('0') value in 'no irq' case. So everything
should be fine.

Other arches might break if some of their OF drivers rely on NO_IRQ
being not 0. If so, the drivers must be fixed, finally.

[ Rob Herring points out that microblaze should be fixed, and has posted
  a patch for testing for that.   - Linus ]
Signed-off-by: NAnton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: NWolfram Sang <w.sang@pengutronix.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With the revert of "of/irq: of_irq_find_parent: check for parent equal to
child" (dc937280), we need another way to handle parent node equal
to the child node. This can simply be handled in of_irq_init by checking
for this condition.
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Tested-by: NPawel Moll <pawel.moll@arm.com>
Tested-by: NStephen Warren <swarren@nvidia.com>

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>