[POWERPC] Add workaround for MPICs with broken register reads

Some versions of PWRficient 1682M have an interrupt controller in which
the first register in each pair for interrupt sources doesn't always
read with the right polarity/sense values.

To work around this, keep a software copy of the register instead.  Since
it's not modified from the mpic itself, it's a feasible solution.  Still,
keep it under a config option to avoid wasting memory on other platforms.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/asm-powerpc/mpic.h b/include/asm-powerpc/mpic.h
index 0eb3ab9ec2bb..edb4a7c84506 100644
--- a/include/asm-powerpc/mpic.h
+++ b/include/asm-powerpc/mpic.h
@@ -306,6 +306,10 @@ struct mpic
         unsigned long           *hwirq_bitmap;
 #endif
 
+#ifdef CONFIG_MPIC_BROKEN_REGREAD
+        u32                     isu_reg0_shadow[MPIC_MAX_IRQ_SOURCES];
+#endif
+
         /* link */
         struct mpic             *next;