1 files changed, 29 insertions, 0 deletions
diff --git a/arch/cris/include/arch-v32/arch/checksum.h b/arch/cris/include/arch-v32/arch/checksum.h
new file mode 100644
index 0000000..e5dcfce
--- /dev/null
+++ b/arch/cris/include/arch-v32/arch/checksum.h
@@ -0,0 +1,29 @@
+#ifndef _ASM_CRIS_ARCH_CHECKSUM_H
+#define _ASM_CRIS_ARCH_CHECKSUM_H
+
+/*
+ * Check values used in TCP/UDP headers.
+ *
+ * The gain of doing this in assembler instead of C, is that C doesn't
+ * generate carry-additions for the 32-bit components of the
+ * checksum. Which means it would be necessary to split all those into
+ * 16-bit components and then add.
+ */
+static inline __wsum
+csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
+		   unsigned short len, unsigned short proto, __wsum sum)
+{
+	__wsum res;
+
+	__asm__ __volatile__ ("add.d %2, %0\n\t"
+			      "addc %3, %0\n\t"
+			      "addc %4, %0\n\t"
+			      "addc 0, %0\n\t"
+			      : "=r" (res)
+			      : "0" (sum), "r" (daddr), "r" (saddr), \
+			      "r" ((len + proto) << 8));
+
+	return res;
+}
+
+#endif /* _ASM_CRIS_ARCH_CHECKSUM_H */