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>

arch/avr32/kernel/avr32_ksyms.c

@@ -58,6 +58,7 @@ EXPORT_SYMBOL(find_first_zero_bit);
 EXPORT_SYMBOL(find_next_zero_bit);
 EXPORT_SYMBOL(find_first_bit);
 EXPORT_SYMBOL(find_next_bit);
+EXPORT_SYMBOL(generic_find_next_le_bit);
 EXPORT_SYMBOL(generic_find_next_zero_le_bit);
 
 /* I/O primitives (lib/io-*.S) */

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