lib/raid6: add ARM-NEON accelerated syndrome calculation

[karo-tx-linux.git] / lib / raid6 / neon.c

diff --git a/lib/raid6/neon.c b/lib/raid6/neon.c
new file mode 100644 (file)
index 0000000..36ad470
--- /dev/null
+++ b/lib/raid6/neon.c
@@ -0,0 +1,58 @@
+/*
+ * linux/lib/raid6/neon.c - RAID6 syndrome calculation using ARM NEON intrinsics
+ *
+ * Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/raid/pq.h>
+
+#ifdef __KERNEL__
+#include <asm/neon.h>
+#else
+#define kernel_neon_begin()
+#define kernel_neon_end()
+#define cpu_has_neon()         (1)
+#endif
+
+/*
+ * There are 2 reasons these wrappers are kept in a separate compilation unit
+ * from the actual implementations in neonN.c (generated from neon.uc by
+ * unroll.awk):
+ * - the actual implementations use NEON intrinsics, and the GCC support header
+ *   (arm_neon.h) is not fully compatible (type wise) with the kernel;
+ * - the neonN.c files are compiled with -mfpu=neon and optimization enabled,
+ *   and we have to make sure that we never use *any* NEON/VFP instructions
+ *   outside a kernel_neon_begin()/kernel_neon_end() pair.
+ */
+
+#define RAID6_NEON_WRAPPER(_n)                                         \
+       static void raid6_neon ## _n ## _gen_syndrome(int disks,        \
+                                       size_t bytes, void **ptrs)      \
+       {                                                               \
+               void raid6_neon ## _n  ## _gen_syndrome_real(int,       \
+                                               unsigned long, void**); \
+               kernel_neon_begin();                                    \
+               raid6_neon ## _n ## _gen_syndrome_real(disks,           \
+                                       (unsigned long)bytes, ptrs);    \
+               kernel_neon_end();                                      \
+       }                                                               \
+       struct raid6_calls const raid6_neonx ## _n = {                  \
+               raid6_neon ## _n ## _gen_syndrome,                      \
+               raid6_have_neon,                                        \
+               "neonx" #_n,                                            \
+               0                                                       \
+       }
+
+static int raid6_have_neon(void)
+{
+       return cpu_has_neon();
+}
+
+RAID6_NEON_WRAPPER(1);
+RAID6_NEON_WRAPPER(2);
+RAID6_NEON_WRAPPER(4);
+RAID6_NEON_WRAPPER(8);