summaryrefslogtreecommitdiffstats
path: root/arch/tile/lib/checksum.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/tile/lib/checksum.c')
-rw-r--r--arch/tile/lib/checksum.c102
1 files changed, 102 insertions, 0 deletions
diff --git a/arch/tile/lib/checksum.c b/arch/tile/lib/checksum.c
new file mode 100644
index 000000000000..e4bab5bd3f31
--- /dev/null
+++ b/arch/tile/lib/checksum.c
@@ -0,0 +1,102 @@
+/*
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ * Support code for the main lib/checksum.c.
+ */
+
+#include <net/checksum.h>
+#include <linux/module.h>
+
+static inline unsigned int longto16(unsigned long x)
+{
+ unsigned long ret;
+#ifdef __tilegx__
+ ret = __insn_v2sadu(x, 0);
+ ret = __insn_v2sadu(ret, 0);
+#else
+ ret = __insn_sadh_u(x, 0);
+ ret = __insn_sadh_u(ret, 0);
+#endif
+ return ret;
+}
+
+__wsum do_csum(const unsigned char *buff, int len)
+{
+ int odd, count;
+ unsigned long result = 0;
+
+ if (len <= 0)
+ goto out;
+ odd = 1 & (unsigned long) buff;
+ if (odd) {
+ result = (*buff << 8);
+ len--;
+ buff++;
+ }
+ count = len >> 1; /* nr of 16-bit words.. */
+ if (count) {
+ if (2 & (unsigned long) buff) {
+ result += *(const unsigned short *)buff;
+ count--;
+ len -= 2;
+ buff += 2;
+ }
+ count >>= 1; /* nr of 32-bit words.. */
+ if (count) {
+#ifdef __tilegx__
+ if (4 & (unsigned long) buff) {
+ unsigned int w = *(const unsigned int *)buff;
+ result = __insn_v2sadau(result, w, 0);
+ count--;
+ len -= 4;
+ buff += 4;
+ }
+ count >>= 1; /* nr of 64-bit words.. */
+#endif
+
+ /*
+ * This algorithm could wrap around for very
+ * large buffers, but those should be impossible.
+ */
+ BUG_ON(count >= 65530);
+
+ while (count) {
+ unsigned long w = *(const unsigned long *)buff;
+ count--;
+ buff += sizeof(w);
+#ifdef __tilegx__
+ result = __insn_v2sadau(result, w, 0);
+#else
+ result = __insn_sadah_u(result, w, 0);
+#endif
+ }
+#ifdef __tilegx__
+ if (len & 4) {
+ unsigned int w = *(const unsigned int *)buff;
+ result = __insn_v2sadau(result, w, 0);
+ buff += 4;
+ }
+#endif
+ }
+ if (len & 2) {
+ result += *(const unsigned short *) buff;
+ buff += 2;
+ }
+ }
+ if (len & 1)
+ result += *buff;
+ result = longto16(result);
+ if (odd)
+ result = swab16(result);
+out:
+ return result;
+}
OpenPOWER on IntegriCloud