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, 6 insertions, 0 deletions

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 5f695041090c..87a06f345bd2 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -108,14 +108,18 @@ enum {
 };
 
 struct msi_desc;
+struct irq_domain;
 
 /**
  * struct irq_data - per irq and irq chip data passed down to chip functions
  * @irq:                interrupt number
+ * @hwirq:              hardware interrupt number, local to the interrupt domain
  * @node:               node index useful for balancing
  * @state_use_accessors: status information for irq chip functions.
  *                      Use accessor functions to deal with it
  * @chip:               low level interrupt hardware access
+ * @domain:             Interrupt translation domain; responsible for mapping
+ *                      between hwirq number and linux irq number.
  * @handler_data:       per-IRQ data for the irq_chip methods
  * @chip_data:          platform-specific per-chip private data for the chip
  *                      methods, to allow shared chip implementations
@@ -128,9 +132,11 @@ struct msi_desc;
  */
 struct irq_data {
         unsigned int            irq;
+        unsigned long           hwirq;
         unsigned int            node;
         unsigned int            state_use_accessors;
         struct irq_chip         *chip;
+        struct irq_domain       *domain;
         void                    *handler_data;
         void                    *chip_data;
         struct msi_desc         *msi_desc;