From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@ppc970.osdl.org>
Date: Sat, 16 Apr 2005 15:20:36 -0700
Subject: Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
---
 include/asm-ppc/checksum.h | 107 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 107 insertions(+)
 create mode 100644 include/asm-ppc/checksum.h

(limited to 'include/asm-ppc/checksum.h')

diff --git a/include/asm-ppc/checksum.h b/include/asm-ppc/checksum.h
new file mode 100644
index 00000000000..cf953a92c7a
--- /dev/null
+++ b/include/asm-ppc/checksum.h
@@ -0,0 +1,107 @@
+#ifdef __KERNEL__
+#ifndef _PPC_CHECKSUM_H
+#define _PPC_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 unsigned int csum_partial(const unsigned char * buff, int len,
+				 unsigned int sum);
+
+/*
+ * Computes the checksum of a memory block at src, length len,
+ * and adds in "sum" (32-bit), while copying the block to dst.
+ * If an access exception occurs on src or dst, it stores -EFAULT
+ * to *src_err or *dst_err respectively (if that pointer is not
+ * NULL), and, for an error on src, zeroes the rest of dst.
+ *
+ * Like csum_partial, this must be called with even lengths,
+ * except for the last fragment.
+ */
+extern unsigned int csum_partial_copy_generic(const char *src, char *dst,
+					      int len, unsigned int sum,
+					      int *src_err, int *dst_err);
+
+#define csum_partial_copy_from_user(src, dst, len, sum, errp)	\
+	csum_partial_copy_generic((__force void *)(src), (dst), (len), (sum), (errp), NULL)
+
+/* FIXME: this needs to be written to really do no check -- Cort */
+#define csum_partial_copy_nocheck(src, dst, len, sum)	\
+	csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
+
+/*
+ * turns a 32-bit partial checksum (e.g. from csum_partial) into a
+ * 1's complement 16-bit checksum.
+ */
+static inline unsigned int csum_fold(unsigned int sum)
+{
+	unsigned int tmp;
+
+	/* swap the two 16-bit halves of sum */
+	__asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
+	/* if there is a carry from adding the two 16-bit halves,
+	   it will carry from the lower half into the upper half,
+	   giving us the correct sum in the upper half. */
+	sum = ~(sum + tmp) >> 16;
+	return sum;
+}
+
+/*
+ * this routine is used for miscellaneous IP-like checksums, mainly
+ * in icmp.c
+ */
+static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
+{
+	return csum_fold(csum_partial(buff, len, 0));
+}
+
+/*
+ * FIXME: I swiped this one from the sparc and made minor modifications.
+ * It may not be correct.  -- Cort
+ */
+static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
+						   unsigned long daddr,
+						   unsigned short len,
+						   unsigned short proto,
+						   unsigned int sum)
+{
+    __asm__("\n\
+	addc %0,%0,%1 \n\
+	adde %0,%0,%2 \n\
+	adde %0,%0,%3 \n\
+	addze %0,%0 \n\
+	"
+	: "=r" (sum)
+	: "r" (daddr), "r"(saddr), "r"((proto<<16)+len), "0"(sum));
+    return sum;
+}
+
+/*
+ * This is a version of ip_compute_csum() optimized for IP headers,
+ * which always checksum on 4 octet boundaries.  ihl is the number
+ * of 32-bit words and is always >= 5.
+ */
+extern unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl);
+
+/*
+ * computes the checksum of the TCP/UDP pseudo-header
+ * returns a 16-bit checksum, already complemented
+ */
+extern unsigned short csum_tcpudp_magic(unsigned long saddr,
+					unsigned long daddr,
+					unsigned short len,
+					unsigned short proto,
+					unsigned int sum);
+
+#endif
+#endif /* __KERNEL__ */
-- 
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