1 files changed, 125 insertions, 0 deletions

diff --git a/drivers/md/mktables.c b/drivers/md/mktables.c
new file mode 100644
index 000000000000..adef299908cf
--- /dev/null
+++ b/drivers/md/mktables.c
@@ -0,0 +1,125 @@
+#ident "$Id: mktables.c,v 1.2 2002/12/12 22:41:27 hpa Exp $"
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2002 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,
+ *   Bostom MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * mktables.c
+ *
+ * Make RAID-6 tables.  This is a host user space program to be run at
+ * compile time.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <time.h>
+
+static uint8_t gfmul(uint8_t a, uint8_t b)
+{
+  uint8_t v = 0;
+
+  while ( b ) {
+    if ( b & 1 ) v ^= a;
+    a = (a << 1) ^ (a & 0x80 ? 0x1d : 0);
+    b >>= 1;
+  }
+  return v;
+}
+
+static uint8_t gfpow(uint8_t a, int b)
+{
+  uint8_t v = 1;
+
+  b %= 255;
+  if ( b < 0 )
+    b += 255;
+
+  while ( b ) {
+    if ( b & 1 ) v = gfmul(v,a);
+    a = gfmul(a,a);
+    b >>= 1;
+  }
+  return v;
+}
+
+int main(int argc, char *argv[])
+{
+  int i, j, k;
+  uint8_t v;
+  uint8_t exptbl[256], invtbl[256];
+
+  printf("#include \"raid6.h\"\n");
+
+  /* Compute multiplication table */
+  printf("\nconst u8  __attribute__((aligned(256)))\n"
+         "raid6_gfmul[256][256] =\n"
+         "{\n");
+  for ( i = 0 ; i < 256 ; i++ ) {
+    printf("\t{\n");
+    for ( j = 0 ; j < 256 ; j += 8 ) {
+      printf("\t\t");
+      for ( k = 0 ; k < 8 ; k++ ) {
+        printf("0x%02x, ", gfmul(i,j+k));
+      }
+      printf("\n");
+    }
+    printf("\t},\n");
+  }
+  printf("};\n");
+
+  /* Compute power-of-2 table (exponent) */
+  v = 1;
+  printf("\nconst u8 __attribute__((aligned(256)))\n"
+         "raid6_gfexp[256] =\n"
+         "{\n");
+  for ( i = 0 ; i < 256 ; i += 8 ) {
+    printf("\t");
+    for ( j = 0 ; j < 8 ; j++ ) {
+      exptbl[i+j] = v;
+      printf("0x%02x, ", v);
+      v = gfmul(v,2);
+      if ( v == 1 ) v = 0;      /* For entry 255, not a real entry */
+    }
+    printf("\n");
+  }
+  printf("};\n");
+
+  /* Compute inverse table x^-1 == x^254 */
+  printf("\nconst u8 __attribute__((aligned(256)))\n"
+         "raid6_gfinv[256] =\n"
+         "{\n");
+  for ( i = 0 ; i < 256 ; i += 8 ) {
+    printf("\t");
+    for ( j = 0 ; j < 8 ; j++ ) {
+      invtbl[i+j] = v = gfpow(i+j,254);
+      printf("0x%02x, ", v);
+    }
+    printf("\n");
+  }
+  printf("};\n");
+
+  /* Compute inv(2^x + 1) (exponent-xor-inverse) table */
+  printf("\nconst u8 __attribute__((aligned(256)))\n"
+         "raid6_gfexi[256] =\n"
+         "{\n");
+  for ( i = 0 ; i < 256 ; i += 8 ) {
+    printf("\t");
+    for ( j = 0 ; j < 8 ; j++ ) {
+      printf("0x%02x, ", invtbl[exptbl[i+j]^1]);
+    }
+    printf("\n");
+  }
+  printf("};\n\n");
+
+  return 0;
+}