1 files changed, 24 insertions, 1 deletions

diff --git a/include/asm-arm/byteorder.h b/include/asm-arm/byteorder.h
index d648a1915c33..17eaf8bdf092 100644
--- a/include/asm-arm/byteorder.h
+++ b/include/asm-arm/byteorder.h
@@ -15,9 +15,32 @@
 #ifndef __ASM_ARM_BYTEORDER_H
 #define __ASM_ARM_BYTEORDER_H
 
-
+#include <linux/compiler.h>
 #include <asm/types.h>
 
+static inline __attribute_const__ __u32 ___arch__swab32(__u32 x)
+{
+        __u32 t;
+
+        if (__builtin_constant_p(x)) {
+                t = x ^ ((x << 16) | (x >> 16)); /* eor r1,r0,r0,ror #16 */
+        } else {
+                /*
+                 * The compiler needs a bit of a hint here to always do the
+                 * right thing and not screw it up to different degrees
+                 * depending on the gcc version.
+                 */
+                asm ("eor\t%0, %1, %1, ror #16" : "=r" (t) : "r" (x));
+        }
+        x = (x << 24) | (x >> 8);               /* mov r0,r0,ror #8      */
+        t &= ~0x00FF0000;                       /* bic r1,r1,#0x00FF0000 */
+        x ^= (t >> 8);                          /* eor r0,r0,r1,lsr #8   */
+
+        return x;
+}
+
+#define __arch__swab32(x) ___arch__swab32(x)
+
 #if !defined(__STRICT_ANSI__) || defined(__KERNEL__)
 #  define __BYTEORDER_HAS_U64__
 #  define __SWAB_64_THRU_32__