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>
diff --git a/lib/Kconfig b/lib/Kconfig
index 54cf309..cd177ca 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -13,6 +13,15 @@
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
diff --git a/lib/bitrev.c b/lib/bitrev.c
index 3956203..40ffda9 100644
--- a/lib/bitrev.c
+++ b/lib/bitrev.c
@@ -1,3 +1,4 @@
+#ifndef CONFIG_HAVE_ARCH_BITREVERSE
#include <linux/types.h>
#include <linux/module.h>
#include <linux/bitrev.h>
@@ -42,18 +43,4 @@
};
EXPORT_SYMBOL_GPL(byte_rev_table);
-u16 bitrev16(u16 x)
-{
- return (bitrev8(x & 0xff) << 8) | bitrev8(x >> 8);
-}
-EXPORT_SYMBOL(bitrev16);
-
-/**
- * bitrev32 - reverse the order of bits in a u32 value
- * @x: value to be bit-reversed
- */
-u32 bitrev32(u32 x)
-{
- return (bitrev16(x & 0xffff) << 16) | bitrev16(x >> 16);
-}
-EXPORT_SYMBOL(bitrev32);
+#endif /* CONFIG_HAVE_ARCH_BITREVERSE */