diff options
| author | Yalin Wang | 2014-11-03 03:01:03 +0100 |
|---|---|---|
| committer | Russell King | 2014-12-22 16:43:06 +0000 |
| commit | 556d2f055bf6d79ce81587dfe774d4dd10da473f (patch) | |
| tree | 3b1eaeda540d1592936691f953607a377668f90f /lib | |
| parent | 97bf6af1f928216fd6c5a66e8a57bfa95a659672 (diff) | |
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>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig | 9 | ||||
| -rw-r--r-- | lib/bitrev.c | 17 |
2 files changed, 11 insertions, 15 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 diff --git a/lib/bitrev.c b/lib/bitrev.c index 3956203456d4..40ffda94cc5d 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 @@ const u8 byte_rev_table[256] = { }; 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 */ |