sh: intc: Implement reverse mapping for IRQs to per-controller IDs.

This implements a scheme roughly analogous to the PowerPC virtual to
hardware IRQ mapping, which we use for IRQ to per-controller ID mapping.
This makes it possible for drivers to use the IDs directly for lookup
instead of hardcoding the vector.

The main motivation for this work is as a building block for dynamically
allocating virtual IRQs for demuxing INTC events sharing a single INTEVT
in addition to a common masking source.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/sh/Kconfig b/drivers/sh/Kconfig
index 1dc8b7ae35fb..e01ae42774af 100644
--- a/drivers/sh/Kconfig
+++ b/drivers/sh/Kconfig
@@ -22,3 +22,12 @@ config INTC_BALANCING
           vectors.
 
           If in doubt, say N.
+
+config INTC_MAPPING_DEBUG
+        bool "Expose IRQ to per-controller id mapping via debugfs"
+        depends on DEBUG_FS
+        help
+          This will create a debugfs entry for showing the relationship
+          between system IRQs and the per-controller id tables.
+
+          If in doubt, say N.