1 files changed, 125 insertions, 0 deletions
diff --git a/arch/openrisc/lib/memcpy.c b/arch/openrisc/lib/memcpy.c
new file mode 100644
index 000000000..fe2177628
--- /dev/null
+++ b/arch/openrisc/lib/memcpy.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * arch/openrisc/lib/memcpy.c
+ *
+ * Optimized memory copy routines for openrisc.  These are mostly copied
+ * from ohter sources but slightly entended based on ideas discuassed in
+ * #openrisc.
+ *
+ * The word unroll implementation is an extension to the arm byte
+ * unrolled implementation, but using word copies (if things are
+ * properly aligned)
+ *
+ * The great arm loop unroll algorithm can be found at:
+ *  arch/arm/boot/compressed/string.c
+ */
+
+#include <linux/export.h>
+
+#include <linux/string.h>
+
+#ifdef CONFIG_OR1K_1200
+/*
+ * Do memcpy with word copies and loop unrolling. This gives the
+ * best performance on the OR1200 and MOR1KX archirectures
+ */
+void *memcpy(void *dest, __const void *src, __kernel_size_t n)
+{
+	int i = 0;
+	unsigned char *d, *s;
+	uint32_t *dest_w = (uint32_t *)dest, *src_w = (uint32_t *)src;
+
+	/* If both source and dest are word aligned copy words */
+	if (!((unsigned int)dest_w & 3) && !((unsigned int)src_w & 3)) {
+		/* Copy 32 bytes per loop */
+		for (i = n >> 5; i > 0; i--) {
+			*dest_w++ = *src_w++;
+			*dest_w++ = *src_w++;
+			*dest_w++ = *src_w++;
+			*dest_w++ = *src_w++;
+			*dest_w++ = *src_w++;
+			*dest_w++ = *src_w++;
+			*dest_w++ = *src_w++;
+			*dest_w++ = *src_w++;
+		}
+
+		if (n & 1 << 4) {
+			*dest_w++ = *src_w++;
+			*dest_w++ = *src_w++;
+			*dest_w++ = *src_w++;
+			*dest_w++ = *src_w++;
+		}
+
+		if (n & 1 << 3) {
+			*dest_w++ = *src_w++;
+			*dest_w++ = *src_w++;
+		}
+
+		if (n & 1 << 2)
+			*dest_w++ = *src_w++;
+
+		d = (unsigned char *)dest_w;
+		s = (unsigned char *)src_w;
+
+	} else {
+		d = (unsigned char *)dest_w;
+		s = (unsigned char *)src_w;
+
+		for (i = n >> 3; i > 0; i--) {
+			*d++ = *s++;
+			*d++ = *s++;
+			*d++ = *s++;
+			*d++ = *s++;
+			*d++ = *s++;
+			*d++ = *s++;
+			*d++ = *s++;
+			*d++ = *s++;
+		}
+
+		if (n & 1 << 2) {
+			*d++ = *s++;
+			*d++ = *s++;
+			*d++ = *s++;
+			*d++ = *s++;
+		}
+	}
+
+	if (n & 1 << 1) {
+		*d++ = *s++;
+		*d++ = *s++;
+	}
+
+	if (n & 1)
+		*d++ = *s++;
+
+	return dest;
+}
+#else
+/*
+ * Use word copies but no loop unrolling as we cannot assume there
+ * will be benefits on the archirecture
+ */
+void *memcpy(void *dest, __const void *src, __kernel_size_t n)
+{
+	unsigned char *d = (unsigned char *)dest, *s = (unsigned char *)src;
+	uint32_t *dest_w = (uint32_t *)dest, *src_w = (uint32_t *)src;
+
+	/* If both source and dest are word aligned copy words */
+	if (!((unsigned int)dest_w & 3) && !((unsigned int)src_w & 3)) {
+		for (; n >= 4; n -= 4)
+			*dest_w++ = *src_w++;
+	}
+
+	d = (unsigned char *)dest_w;
+	s = (unsigned char *)src_w;
+
+	/* For remaining or if not aligned, copy bytes */
+	for (; n >= 1; n -= 1)
+		*d++ = *s++;
+
+	return dest;
+
+}
+#endif
+
+EXPORT_SYMBOL(memcpy);