irq: add irq_domain translation infrastructure

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

1 files changed, 0 insertions, 14 deletions

diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
index 0cdd7b456cb..1a33e9d6bb1 100644
--- a/arch/arm/kernel/devtree.c
+++ b/arch/arm/kernel/devtree.c
@@ -132,17 +132,3 @@ struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
 
 	return mdesc_best;
 }
-
-/**
- * irq_create_of_mapping - Hook to resolve OF irq specifier into a Linux irq#
- *
- * Currently the mapping mechanism is trivial; simple flat hwirq numbers are
- * mapped 1:1 onto Linux irq numbers.  Cascaded irq controllers are not
- * supported.
- */
-unsigned int irq_create_of_mapping(struct device_node *controller,
-				   const u32 *intspec, unsigned int intsize)
-{
-	return intspec[0];
-}
-EXPORT_SYMBOL_GPL(irq_create_of_mapping);