summaryrefslogtreecommitdiffstats
path: root/arch/tile/include/asm
diff options
context:
space:
mode:
authorChris Metcalf <cmetcalf@tilera.com>2012-04-28 21:41:39 +0200
committerChris Metcalf <cmetcalf@tilera.com>2012-07-11 22:04:57 +0200
commit10104a1ad670889adc1ae3779df968db621b5dbd (patch)
tree1a5aa6b3ae5c669b818bf076f748a8a54d27f88f /arch/tile/include/asm
parentarch/tile: provide kernel support for the tilegx mPIPE shim (diff)
downloadlinux-10104a1ad670889adc1ae3779df968db621b5dbd.tar.xz
linux-10104a1ad670889adc1ae3779df968db621b5dbd.zip
arch/tile: break out the "csum a long" function to <asm/checksum.h>
This makes it available to the tilegx network driver. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Diffstat (limited to 'arch/tile/include/asm')
-rw-r--r--arch/tile/include/asm/checksum.h18
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/tile/include/asm/checksum.h b/arch/tile/include/asm/checksum.h
index a120766c7264..b21a2fdec9f7 100644
--- a/arch/tile/include/asm/checksum.h
+++ b/arch/tile/include/asm/checksum.h
@@ -21,4 +21,22 @@
__wsum do_csum(const unsigned char *buff, int len);
#define do_csum do_csum
+/*
+ * Return the sum of all the 16-bit subwords in a long.
+ * This sums two subwords on a 32-bit machine, and four on 64 bits.
+ * The implementation does two vector adds to capture any overflow.
+ */
+static inline unsigned int csum_long(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;
+}
+
#endif /* _ASM_TILE_CHECKSUM_H */