Merge branch 'async' of macbook:git/btrfs-unstable

[pandora-kernel.git] / lib / raid6 / raid6altivec.uc

diff --git a/lib/raid6/raid6altivec.uc b/lib/raid6/raid6altivec.uc
new file mode 100644 (file)
index 0000000..2654d5c
--- /dev/null
+++ b/lib/raid6/raid6altivec.uc
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+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ *   Copyright 2002-2004 H. Peter Anvin - All Rights Reserved
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * raid6altivec$#.c
+ *
+ * $#-way unrolled portable integer math RAID-6 instruction set
+ *
+ * This file is postprocessed using unroll.awk
+ *
+ * <benh> hpa: in process,
+ * you can just "steal" the vec unit with enable_kernel_altivec() (but
+ * bracked this with preempt_disable/enable or in a lock)
+ */
+
+#include <linux/raid/pq.h>
+
+#ifdef CONFIG_ALTIVEC
+
+#include <altivec.h>
+#ifdef __KERNEL__
+# include <asm/system.h>
+# include <asm/cputable.h>
+#endif
+
+/*
+ * This is the C data type to use.  We use a vector of
+ * signed char so vec_cmpgt() will generate the right
+ * instruction.
+ */
+
+typedef vector signed char unative_t;
+
+#define NBYTES(x) ((vector signed char) {x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x})
+#define NSIZE  sizeof(unative_t)
+
+/*
+ * The SHLBYTE() operation shifts each byte left by 1, *not*
+ * rolling over into the next byte
+ */
+static inline __attribute_const__ unative_t SHLBYTE(unative_t v)
+{
+       return vec_add(v,v);
+}
+
+/*
+ * The MASK() operation returns 0xFF in any byte for which the high
+ * bit is 1, 0x00 for any byte for which the high bit is 0.
+ */
+static inline __attribute_const__ unative_t MASK(unative_t v)
+{
+       unative_t zv = NBYTES(0);
+
+       /* vec_cmpgt returns a vector bool char; thus the need for the cast */
+       return (unative_t)vec_cmpgt(zv, v);
+}
+
+
+/* This is noinline to make damned sure that gcc doesn't move any of the
+   Altivec code around the enable/disable code */
+static void noinline
+raid6_altivec$#_gen_syndrome_real(int disks, size_t bytes, void **ptrs)
+{
+       u8 **dptr = (u8 **)ptrs;
+       u8 *p, *q;
+       int d, z, z0;
+
+       unative_t wd$$, wq$$, wp$$, w1$$, w2$$;
+       unative_t x1d = NBYTES(0x1d);
+
+       z0 = disks - 3;         /* Highest data disk */
+       p = dptr[z0+1];         /* XOR parity */
+       q = dptr[z0+2];         /* RS syndrome */
+
+       for ( d = 0 ; d < bytes ; d += NSIZE*$# ) {
+               wq$$ = wp$$ = *(unative_t *)&dptr[z0][d+$$*NSIZE];
+               for ( z = z0-1 ; z >= 0 ; z-- ) {
+                       wd$$ = *(unative_t *)&dptr[z][d+$$*NSIZE];
+                       wp$$ = vec_xor(wp$$, wd$$);
+                       w2$$ = MASK(wq$$);
+                       w1$$ = SHLBYTE(wq$$);
+                       w2$$ = vec_and(w2$$, x1d);
+                       w1$$ = vec_xor(w1$$, w2$$);
+                       wq$$ = vec_xor(w1$$, wd$$);
+               }
+               *(unative_t *)&p[d+NSIZE*$$] = wp$$;
+               *(unative_t *)&q[d+NSIZE*$$] = wq$$;
+       }
+}
+
+static void raid6_altivec$#_gen_syndrome(int disks, size_t bytes, void **ptrs)
+{
+       preempt_disable();
+       enable_kernel_altivec();
+
+       raid6_altivec$#_gen_syndrome_real(disks, bytes, ptrs);
+
+       preempt_enable();
+}
+
+int raid6_have_altivec(void);
+#if $# == 1
+int raid6_have_altivec(void)
+{
+       /* This assumes either all CPUs have Altivec or none does */
+# ifdef __KERNEL__
+       return cpu_has_feature(CPU_FTR_ALTIVEC);
+# else
+       return 1;
+# endif
+}
+#endif
+
+const struct raid6_calls raid6_altivec$# = {
+       raid6_altivec$#_gen_syndrome,
+       raid6_have_altivec,
+       "altivecx$#",
+       0
+};
+
+#endif /* CONFIG_ALTIVEC */