[PATCH 2/4] parisc: checksum: Use generic implementations

[Charlie Jenkins <charlie@rivosinc.com>]

The generic implementations of the checksum functions
csum_tcpudp_nofold, csum_fold, and ip_compute_csum are either identical
or perform better than the parisc ones, so use the generic
implementations instead.

In order to use the generic implementations of checksum functions,
do_csum can no longer be static.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
 arch/parisc/Kconfig                |  3 +++
 arch/parisc/include/asm/checksum.h | 42 ++++++++------------------------------
 arch/parisc/lib/checksum.c         |  2 +-
 3 files changed, 13 insertions(+), 34 deletions(-)

diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index d14ccc948a29..1638deb23287 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -122,6 +122,9 @@ config GENERIC_BUG
 config GENERIC_BUG_RELATIVE_POINTERS
 	bool
 
+config GENERIC_CSUM
+	def_bool y
+
 config GENERIC_HWEIGHT
 	bool
 	default y
diff --git a/arch/parisc/include/asm/checksum.h b/arch/parisc/include/asm/checksum.h
index 3c43baca7b39..c7847a08ef7c 100644
--- a/arch/parisc/include/asm/checksum.h
+++ b/arch/parisc/include/asm/checksum.h
@@ -17,6 +17,7 @@
  * it's best to have buff aligned on a 32-bit boundary
  */
 extern __wsum csum_partial(const void *, int, __wsum);
+#define csum_partial csum_partial
 
 /*
  *	Optimized for IP headers, which always checksum on 4 octet boundaries.
@@ -57,20 +58,8 @@ static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
 	return (__force __sum16)sum;
 }
 
-/*
- *	Fold a partial checksum
- */
-static inline __sum16 csum_fold(__wsum csum)
-{
-	u32 sum = (__force u32)csum;
-	/* add the swapped two 16-bit halves of sum,
-	   a possible carry from adding the two 16-bit halves,
-	   will carry from the lower half into the upper half,
-	   giving us the correct sum in the upper half. */
-	sum += (sum << 16) + (sum >> 16);
-	return (__force __sum16)(~sum >> 16);
-}
- 
+#define ip_fast_csum ip_fast_csum
+
 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
 					__u32 len, __u8 proto,
 					__wsum sum)
@@ -85,28 +74,15 @@ static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
 	return sum;
 }
 
-/*
- * computes the checksum of the TCP/UDP pseudo-header
- * returns a 16-bit checksum, already complemented
- */
-static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
-					__u32 len, __u8 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
- */
-static inline __sum16 ip_compute_csum(const void *buf, int len)
-{
-	 return csum_fold (csum_partial(buf, len, 0));
-}
+#define csum_tcpudp_nofold csum_tcpudp_nofold
 
+extern unsigned int do_csum(const unsigned char *buff, int len);
+#define do_csum do_csum
 
 #define _HAVE_ARCH_IPV6_CSUM
+
+#include <asm-generic/checksum.h>
+
 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 					  const struct in6_addr *daddr,
 					  __u32 len, __u8 proto,
diff --git a/arch/parisc/lib/checksum.c b/arch/parisc/lib/checksum.c
index 4818f3db84a5..05f5ca4b2f96 100644
--- a/arch/parisc/lib/checksum.c
+++ b/arch/parisc/lib/checksum.c
@@ -34,7 +34,7 @@ static inline unsigned short from32to16(unsigned int x)
 	return (unsigned short)x;
 }
 
-static inline unsigned int do_csum(const unsigned char * buff, int len)
+unsigned int do_csum(const unsigned char *buff, int len)
 {
 	int odd, count;
 	unsigned int result = 0;

-- 
2.34.1