metag: Optimised library functions

[cascardo/linux.git] / arch / metag / include / asm / checksum.h

diff --git a/arch/metag/include/asm/checksum.h b/arch/metag/include/asm/checksum.h
new file mode 100644 (file)
index 0000000..999bf76
--- /dev/null
+++ b/arch/metag/include/asm/checksum.h
@@ -0,0 +1,92 @@
+#ifndef _METAG_CHECKSUM_H
+#define _METAG_CHECKSUM_H
+
+/*
+ * computes the checksum of a memory block at buff, length len,
+ * and adds in "sum" (32-bit)
+ *
+ * returns a 32-bit number suitable for feeding into itself
+ * or csum_tcpudp_magic
+ *
+ * this function must be called with even lengths, except
+ * for the last fragment, which may be odd
+ *
+ * it's best to have buff aligned on a 32-bit boundary
+ */
+extern __wsum csum_partial(const void *buff, int len, __wsum sum);
+
+/*
+ * the same as csum_partial, but copies from src while it
+ * checksums
+ *
+ * here even more important to align src and dst on a 32-bit (or even
+ * better 64-bit) boundary
+ */
+extern __wsum csum_partial_copy(const void *src, void *dst, int len,
+                               __wsum sum);
+
+/*
+ * the same as csum_partial_copy, but copies from user space.
+ *
+ * here even more important to align src and dst on a 32-bit (or even
+ * better 64-bit) boundary
+ */
+extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
+                                       int len, __wsum sum, int *csum_err);
+
+#define csum_partial_copy_nocheck(src, dst, len, sum)  \
+       csum_partial_copy((src), (dst), (len), (sum))
+
+/*
+ * Fold a partial checksum
+ */
+static inline __sum16 csum_fold(__wsum csum)
+{
+       u32 sum = (__force u32)csum;
+       sum = (sum & 0xffff) + (sum >> 16);
+       sum = (sum & 0xffff) + (sum >> 16);
+       return (__force __sum16)~sum;
+}
+
+/*
+ * This is a version of ip_compute_csum() optimized for IP headers,
+ * which always checksum on 4 octet boundaries.
+ */
+extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
+
+/*
+ * computes the checksum of the TCP/UDP pseudo-header
+ * returns a 16-bit checksum, already complemented
+ */
+static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
+                                       unsigned short len,
+                                       unsigned short proto,
+                                       __wsum sum)
+{
+       unsigned long len_proto = (proto + len) << 8;
+       asm ("ADD    %0, %0, %1\n"
+            "ADDS   %0, %0, %2\n"
+            "ADDCS  %0, %0, #1\n"
+            "ADDS   %0, %0, %3\n"
+            "ADDCS  %0, %0, #1\n"
+            : "=d" (sum)
+            : "d" (daddr), "d" (saddr), "d" (len_proto),
+              "0" (sum)
+            : "cc");
+       return sum;
+}
+
+static inline __sum16
+csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len,
+                 unsigned short proto, __wsum sum)
+{
+       return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
+}
+
+/*
+ * this routine is used for miscellaneous IP-like checksums, mainly
+ * in icmp.c
+ */
+extern __sum16 ip_compute_csum(const void *buff, int len);
+
+#endif /* _METAG_CHECKSUM_H */