MIPS: lib: memcpy: Add MIPS R6 support

MIPS R6 does not support the unaligned load and store instructions
so we add a special MIPS R6 case to copy one byte at a time if we
need to read/write to unaligned memory addresses.
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

arch/mips/lib/memcpy.S

@@ -293,9 +293,14 @@
 	 and	t0, src, ADDRMASK
 	PREFS(	0, 2*32(src) )
 	PREFD(	1, 2*32(dst) )
+#ifndef CONFIG_CPU_MIPSR6
 	bnez	t1, .Ldst_unaligned\@
 	 nop
 	bnez	t0, .Lsrc_unaligned_dst_aligned\@
+#else
+	or	t0, t0, t1
+	bnez	t0, .Lcopy_unaligned_bytes\@
+#endif
 	/*
 	 * use delay slot for fall-through
 	 * src and dst are aligned; need to compute rem
@@ -376,6 +381,7 @@
 	bne	rem, len, 1b
 	.set	noreorder
 
+#ifndef CONFIG_CPU_MIPSR6
 	/*
 	 * src and dst are aligned, need to copy rem bytes (rem < NBYTES)
 	 * A loop would do only a byte at a time with possible branch
@@ -477,6 +483,7 @@
 	bne	len, rem, 1b
 	.set	noreorder
 
+#endif /* !CONFIG_CPU_MIPSR6 */
 .Lcopy_bytes_checklen\@:
 	beqz	len, .Ldone\@
 	 nop
@@ -504,6 +511,22 @@
 .Ldone\@:
 	jr	ra
 	 nop
+
+#ifdef CONFIG_CPU_MIPSR6
+.Lcopy_unaligned_bytes\@:
+1:
+	COPY_BYTE(0)
+	COPY_BYTE(1)
+	COPY_BYTE(2)
+	COPY_BYTE(3)
+	COPY_BYTE(4)
+	COPY_BYTE(5)
+	COPY_BYTE(6)
+	COPY_BYTE(7)
+	ADD	src, src, 8
+	b	1b
+	 ADD	dst, dst, 8
+#endif /* CONFIG_CPU_MIPSR6 */
 	.if __memcpy == 1
 	END(memcpy)
 	.set __memcpy, 0