This allows us to move duplicated code in <asm/atomic.h>
(atomic_inc_not_zero() for now) to <linux/atomic.h>

Signed-off-by: Arun Sharma <asharma@fb.com>
Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Move irq_choose_cpu() into arch/powerpc/kernel/irq.c so that it can be used
by other PIC drivers.  The function is not MPIC-specific.

Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com>
Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

The only references to the irq_map[].host field are internal to
arch/powerpc/kernel/irq.c

Signed-off-by: Milton Miller <miltonm@bga.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Some irq_host implementations are using virq_to_host to check if
they are the irq_host for a virtual irq.  To allow us to make space
versus time tradeoffs, replace this usage with an assertive
virq_is_host that confirms or denies the irq is associated with the
given irq_host.

Signed-off-by: Milton Miller <miltonm@bga.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

It was called from irq_create_mapping if that was called for a host
and hwirq that was previously mapped, "to update the flags".  But the
only implementation was in beat_interrupt and all it did was repeat a
hypervisor call without error checking that was performed with error
checking at the beginning of the map hook.  In addition, the comment on
the beat remap hook says it will only called once for a given mapping,
which would apply to map not remap.

All flags should be known by the time the match hook is called, before
we call the map hook.  Removing this mostly unused hook will simpify
the requirements of irq_domain concept.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

First step in eliminating irq_map[] table entirely

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This is a significant rework of the XICS driver, too significant to
conveniently break it up into a series of smaller patches to be honest.

The driver is moved to a more generic location to allow new platforms
to use it, and is broken up into separate ICP and ICS "backends". For
now we have the native and "hypervisor" ICP backends and one common
RTAS ICS backend.

The driver supports one ICP backend instanciation, and many ICS ones,
in order to accomodate future platforms with multiple possibly different
interrupt "sources" mechanisms.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Conflicts:
	arch/sparc/kernel/prom_64.c

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>

Irq stacks provide an essential protection from stack overflows through
external interrupts, at the cost of two additionals stacks per CPU.

Enable them unconditionally to simplify the kernel build and prevent
people from accidentally disabling them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>