ARM: 8187/1: add CONFIG_HAVE_ARCH_BITREVERSE to support rbit instruction

this change add CONFIG_HAVE_ARCH_BITREVERSE config option,
so that we can use some architecture's bitrev hardware instruction
to do bitrev operation.

Introduce __constant_bitrev* macro for constant bitrev operation.

Change __bitrev16() __bitrev32() to be inline function,
don't need export symbol for these tiny functions.

Signed-off-by: Yalin Wang <yalin.wang@sonymobile.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 9 insertions, 0 deletions

diff --git a/lib/Kconfig b/lib/Kconfig
index 54cf309a92a5..cd177caf3876 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -13,6 +13,15 @@ config RAID6_PQ
 config BITREVERSE
         tristate
 
+config HAVE_ARCH_BITREVERSE
+        boolean
+        default n
+        depends on BITREVERSE
+        help
+          This option provides an config for the architecture which have instruction
+          can do bitreverse operation, we use the hardware instruction if the architecture
+          have this capability.
+
 config RATIONAL
         boolean