crc32: bolt on crc32c

Reuse the existing crc32 code to stamp out a crc32c implementation.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Bob Pearson <rpearson@systemfabricworks.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 28 insertions, 7 deletions

diff --git a/lib/gen_crc32table.c b/lib/gen_crc32table.c
index 0d9edd17ee13..8f8d5439e2d9 100644
--- a/lib/gen_crc32table.c
+++ b/lib/gen_crc32table.c
@@ -23,6 +23,7 @@
 
 static uint32_t crc32table_le[LE_TABLE_ROWS][256];
 static uint32_t crc32table_be[BE_TABLE_ROWS][256];
+static uint32_t crc32ctable_le[LE_TABLE_ROWS][256];
 
 /**
  * crc32init_le() - allocate and initialize LE table data
@@ -31,27 +32,38 @@ static uint32_t crc32table_be[BE_TABLE_ROWS][256];
  * fact that crctable[i^j] = crctable[i] ^ crctable[j].
  *
  */
-static void crc32init_le(void)
+static void crc32init_le_generic(const uint32_t polynomial,
+                                 uint32_t (*tab)[256])
 {
         unsigned i, j;
         uint32_t crc = 1;
 
-        crc32table_le[0][0] = 0;
+        tab[0][0] = 0;
 
         for (i = LE_TABLE_SIZE >> 1; i; i >>= 1) {
-                crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY_LE : 0);
+                crc = (crc >> 1) ^ ((crc & 1) ? polynomial : 0);
                 for (j = 0; j < LE_TABLE_SIZE; j += 2 * i)
-                        crc32table_le[0][i + j] = crc ^ crc32table_le[0][j];
+                        tab[0][i + j] = crc ^ tab[0][j];
         }
         for (i = 0; i < LE_TABLE_SIZE; i++) {
-                crc = crc32table_le[0][i];
+                crc = tab[0][i];
                 for (j = 1; j < LE_TABLE_ROWS; j++) {
-                        crc = crc32table_le[0][crc & 0xff] ^ (crc >> 8);
-                        crc32table_le[j][i] = crc;
+                        crc = tab[0][crc & 0xff] ^ (crc >> 8);
+                        tab[j][i] = crc;
                 }
         }
 }
 
+static void crc32init_le(void)
+{
+        crc32init_le_generic(CRCPOLY_LE, crc32table_le);
+}
+
+static void crc32cinit_le(void)
+{
+        crc32init_le_generic(CRC32C_POLY_LE, crc32ctable_le);
+}
+
 /**
  * crc32init_be() - allocate and initialize BE table data
  */
@@ -114,6 +126,15 @@ int main(int argc, char** argv)
                              BE_TABLE_SIZE, "tobe");
                 printf("};\n");
         }
+        if (CRC_LE_BITS > 1) {
+                crc32cinit_le();
+                printf("static const u32 __cacheline_aligned "
+                       "crc32ctable_le[%d][%d] = {",
+                       LE_TABLE_ROWS, LE_TABLE_SIZE);
+                output_table(crc32ctable_le, LE_TABLE_ROWS,
+                             LE_TABLE_SIZE, "tole");
+                printf("};\n");
+        }
 
         return 0;
 }