1 files changed, 108 insertions, 0 deletions
diff --git a/arch/parisc/lib/checksum.c b/arch/parisc/lib/checksum.c
new file mode 100644
index 000000000..4818f3db8
--- /dev/null
+++ b/arch/parisc/lib/checksum.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * INET		An implementation of the TCP/IP protocol suite for the LINUX
+ *		operating system.  INET is implemented using the  BSD Socket
+ *		interface as the means of communication with the user level.
+ *
+ *		MIPS specific IP/TCP/UDP checksumming routines
+ *
+ * Authors:	Ralf Baechle, <ralf@waldorf-gmbh.de>
+ *		Lots of code moved from tcp.c and ip.c; see those files
+ *		for more names.
+ */
+#include <linux/module.h>
+#include <linux/types.h>
+
+#include <net/checksum.h>
+#include <asm/byteorder.h>
+#include <asm/string.h>
+#include <linux/uaccess.h>
+
+#define addc(_t,_r)                     \
+	__asm__ __volatile__ (          \
+"       add             %0, %1, %0\n"   \
+"       addc            %0, %%r0, %0\n" \
+	: "=r"(_t)                      \
+	: "r"(_r), "0"(_t));
+
+static inline unsigned short from32to16(unsigned int x)
+{
+	/* 32 bits --> 16 bits + carry */
+	x = (x & 0xffff) + (x >> 16);
+	/* 16 bits + carry --> 16 bits including carry */
+	x = (x & 0xffff) + (x >> 16);
+	return (unsigned short)x;
+}
+
+static inline unsigned int do_csum(const unsigned char * buff, int len)
+{
+	int odd, count;
+	unsigned int result = 0;
+
+	if (len <= 0)
+		goto out;
+	odd = 1 & (unsigned long) buff;
+	if (odd) {
+		result = be16_to_cpu(*buff);
+		len--;
+		buff++;
+	}
+	count = len >> 1;		/* nr of 16-bit words.. */
+	if (count) {
+		if (2 & (unsigned long) buff) {
+			result += *(unsigned short *) buff;
+			count--;
+			len -= 2;
+			buff += 2;
+		}
+		count >>= 1;		/* nr of 32-bit words.. */
+		if (count) {
+			while (count >= 4) {
+				unsigned int r1, r2, r3, r4;
+				r1 = *(unsigned int *)(buff + 0);
+				r2 = *(unsigned int *)(buff + 4);
+				r3 = *(unsigned int *)(buff + 8);
+				r4 = *(unsigned int *)(buff + 12);
+				addc(result, r1);
+				addc(result, r2);
+				addc(result, r3);
+				addc(result, r4);
+				count -= 4;
+				buff += 16;
+			}
+			while (count) {
+				unsigned int w = *(unsigned int *) buff;
+				count--;
+				buff += 4;
+				addc(result, w);
+			}
+			result = (result & 0xffff) + (result >> 16);
+		}
+		if (len & 2) {
+			result += *(unsigned short *) buff;
+			buff += 2;
+		}
+	}
+	if (len & 1)
+		result += le16_to_cpu(*buff);
+	result = from32to16(result);
+	if (odd)
+		result = swab16(result);
+out:
+	return result;
+}
+
+/*
+ * computes a partial checksum, e.g. for TCP/UDP fragments
+ */
+/*
+ * why bother folding?
+ */
+__wsum csum_partial(const void *buff, int len, __wsum sum)
+{
+	unsigned int result = do_csum(buff, len);
+	addc(result, sum);
+	return (__force __wsum)from32to16(result);
+}
+
+EXPORT_SYMBOL(csum_partial);