[PATCH RFC] ARM/IRQ-Crossbar: Make Xen aware of devices being statically mapped in the IRQ crossbar.

[Brandon Perez <bperez-1@ti.com>]

In general, Xen needs to own very few interrupts to run. Most of these are timer
PPIs, which do not involve the crossbar. The notable exception to this is the
serial device, which is an SPI. On the DRA7 chips, this involves going through
the interrupt crossbar.

As the device tree entry will contain the crossbar input number, and not the
IRQ line, Xen must be given the SPI input line number. This is achieved with
the "default-mapping" property, which contains the SPI number that the device
will correspond to in the mapping setup by the bootloader.

Signed-off-by: Brandon Perez <bperez-1@ti.com>
---
 xen/common/device_tree.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index 31f169b..fc82eb4 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -1036,10 +1036,13 @@ int dt_device_get_raw_irq(const struct dt_device_node *device,
     dt_dprintk("dt_device_get_raw_irq: dev=%s, index=%u\n",
                device->full_name, index);

-    /* Get the interrupts property */
-    intspec = dt_get_property(device, "interrupts", &intlen);
-    if ( intspec == NULL )
-        return -EINVAL;
+    /* Get the appropiate interrupts property */
+    intspec = dt_get_property(device, "default-mapping", &intlen);
+    if (intspec == NULL) {
+        intspec = dt_get_property(device, "interrupts", &intlen);
+        if (intspec == NULL)
+            return -EINVAL;
+    }
     intlen /= sizeof(*intspec);

     dt_dprintk(" intspec=%d intlen=%d\n", be32_to_cpup(intspec), intlen);
--
1.7.9.5