avr32: add generic_find_next_le_bit bit function

This patch implements the generic_find_next_le_bit bit function for AVR32
architecture. This is used by EXT4 file system.

Signed-off-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/arch/avr32/lib/findbit.S b/arch/avr32/lib/findbit.S
index c6b91dee857c..997b33b2288a 100644
--- a/arch/avr32/lib/findbit.S
+++ b/arch/avr32/lib/findbit.S
@@ -123,6 +123,36 @@ ENTRY(find_next_bit)
         brgt    1b
         retal   r11
 
+ENTRY(generic_find_next_le_bit)
+        lsr     r8, r10, 5
+        sub     r9, r11, r10
+        retle   r11
+
+        lsl     r8, 2
+        add     r12, r8
+        andl    r10, 31, COH
+        breq    1f
+
+        /* offset is not word-aligned. Handle the first (32 - r10) bits */
+        ldswp.w r8, r12[0]
+        sub     r12, -4
+        lsr     r8, r8, r10
+        brne    .L_found
+
+        /* r9 = r9 - (32 - r10) = r9 + r10 - 32 */
+        add     r9, r10
+        sub     r9, 32
+        retle   r11
+
+        /* Main loop. offset must be word-aligned */
+1:      ldswp.w r8, r12[0]
+        cp.w    r8, 0
+        brne    .L_found
+        sub     r12, -4
+        sub     r9, 32
+        brgt    1b
+        retal   r11
+
 ENTRY(generic_find_next_zero_le_bit)
         lsr     r8, r10, 5
         sub     r9, r11, r10