root/lib/crc32defs.h

INCLUDED FROM

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 
   3 /* Try to choose an implementation variant via Kconfig */
   4 #ifdef CONFIG_CRC32_SLICEBY8
   5 # define CRC_LE_BITS 64
   6 # define CRC_BE_BITS 64
   7 #endif
   8 #ifdef CONFIG_CRC32_SLICEBY4
   9 # define CRC_LE_BITS 32
  10 # define CRC_BE_BITS 32
  11 #endif
  12 #ifdef CONFIG_CRC32_SARWATE
  13 # define CRC_LE_BITS 8
  14 # define CRC_BE_BITS 8
  15 #endif
  16 #ifdef CONFIG_CRC32_BIT
  17 # define CRC_LE_BITS 1
  18 # define CRC_BE_BITS 1
  19 #endif
  20 
  21 /*
  22  * How many bits at a time to use.  Valid values are 1, 2, 4, 8, 32 and 64.
  23  * For less performance-sensitive, use 4 or 8 to save table size.
  24  * For larger systems choose same as CPU architecture as default.
  25  * This works well on X86_64, SPARC64 systems. This may require some
  26  * elaboration after experiments with other architectures.
  27  */
  28 #ifndef CRC_LE_BITS
  29 #  ifdef CONFIG_64BIT
  30 #  define CRC_LE_BITS 64
  31 #  else
  32 #  define CRC_LE_BITS 32
  33 #  endif
  34 #endif
  35 #ifndef CRC_BE_BITS
  36 #  ifdef CONFIG_64BIT
  37 #  define CRC_BE_BITS 64
  38 #  else
  39 #  define CRC_BE_BITS 32
  40 #  endif
  41 #endif
  42 
  43 /*
  44  * Little-endian CRC computation.  Used with serial bit streams sent
  45  * lsbit-first.  Be sure to use cpu_to_le32() to append the computed CRC.
  46  */
  47 #if CRC_LE_BITS > 64 || CRC_LE_BITS < 1 || CRC_LE_BITS == 16 || \
  48         CRC_LE_BITS & CRC_LE_BITS-1
  49 # error "CRC_LE_BITS must be one of {1, 2, 4, 8, 32, 64}"
  50 #endif
  51 
  52 /*
  53  * Big-endian CRC computation.  Used with serial bit streams sent
  54  * msbit-first.  Be sure to use cpu_to_be32() to append the computed CRC.
  55  */
  56 #if CRC_BE_BITS > 64 || CRC_BE_BITS < 1 || CRC_BE_BITS == 16 || \
  57         CRC_BE_BITS & CRC_BE_BITS-1
  58 # error "CRC_BE_BITS must be one of {1, 2, 4, 8, 32, 64}"
  59 #endif