powerpc/mpic: Fix incorrect allocation of interrupt rev-map

Before when we were setting up the irq host map for mpic we passed in
just isu_size for the size of the linear map.  However, for a number of
mpic implementations we have no isu (thus pass in 0) and will end up
with a no linear map (size = 0).  This causes us to always call
irq_find_mapping() from mpic_get_irq().

By moving the allocation of the host map to after we've determined the
number of sources we can actually benefit from having a linear map for
the non-isu users that covers all the interrupt sources.

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

1 files changed, 9 insertions, 7 deletions

diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c
index 21b956701596..0efc12d1a3d7 100644
--- a/arch/powerpc/sysdev/mpic.c
+++ b/arch/powerpc/sysdev/mpic.c
@@ -1057,13 +1057,6 @@ struct mpic * __init mpic_alloc(struct device_node *node,
         memset(mpic, 0, sizeof(struct mpic));
         mpic->name = name;
 
-        mpic->irqhost = irq_alloc_host(node, IRQ_HOST_MAP_LINEAR,
-                                       isu_size, &mpic_host_ops,
-                                       flags & MPIC_LARGE_VECTORS ? 2048 : 256);
-        if (mpic->irqhost == NULL)
-                return NULL;
-
-        mpic->irqhost->host_data = mpic;
         mpic->hc_irq = mpic_irq_chip;
         mpic->hc_irq.typename = name;
         if (flags & MPIC_PRIMARY)
@@ -1213,6 +1206,15 @@ struct mpic * __init mpic_alloc(struct device_node *node,
         mpic->isu_shift = 1 + __ilog2(mpic->isu_size - 1);
         mpic->isu_mask = (1 << mpic->isu_shift) - 1;
 
+        mpic->irqhost = irq_alloc_host(node, IRQ_HOST_MAP_LINEAR,
+                                       isu_size ? isu_size : mpic->num_sources,
+                                       &mpic_host_ops,
+                                       flags & MPIC_LARGE_VECTORS ? 2048 : 256);
+        if (mpic->irqhost == NULL)
+                return NULL;
+
+        mpic->irqhost->host_data = mpic;
+
         /* Display version */
         switch (greg_feature & MPIC_GREG_FEATURE_VERSION_MASK) {
         case 1: