jnand_crc.c

QUALCOMM JNAND DRIVER

/*====*====*====*====*====*====*====*====*====*====*====*====*====*====*====*

                        C R C    S E R V I C E S

GENERAL DESCRIPTION
  This module contains functions for calculating a checksum for the code
  image programmed into NAND flash by JNAND utility

REFERENCES
  CRC-30, CAI Section 6.7.1.2.2, 7.7.1.2.2, 7.7.2.2.2

EXTERNALIZED FUNCTIONS
  crc_30_step - calculate a step-by-step 30-bit CRC over disjunct data.

INITIALIZATION AND SEQUENCING REQUIREMENTS
  None

Copyright (c) 1990-1992 by QUALCOMM, Incorporated.  All Rights Reserved.
Copyright (c) 1996-1999 by QUALCOMM, Incorporated.  All Rights Reserved.
*====*====*====*====*====*====*====*====*====*====*====*====*====*====*====*/


/*===========================================================================

                        EDIT HISTORY FOR MODULE

This section contains comments describing changes made to the module.
Notice that changes are listed in reverse chronological order.

$Header: //depot/asic/MSMSHARED/tools/jnand/jnand_crc.c#1 $ $DateTime: 2003/02/06 15:47:46 $ $Author: pingguan $

when       who     what, where, why
--------   ---     ----------------------------------------------------------
02/06/03   pg      Moved from ASWP402 server to ASWP401 server.
07/04/02   drh     Removed reference to crc_30_calc as we only use the step
06/19/02   drh     Removed all 16 bit CRC functions not used in JNAND
11/29/01   lad     Added step-wise CRC30 calculation.
04/09/99   ms      Lint cleanup.
03/17/99   ms      Changes for Virtual Boot Block.
                      Removed bb_ prefixes
                      Not includingbbjmpout.h
12/16/98   jct     Removed 80186 support
09/28/98   jct     Incorporate ARM changes
04/08/96   dna     Added comment to each func. saying it is in the Boot Block
02/28/96   dna     Merged crctab.c into this file for Boot Block because the
                   external references to the tables caused a problem.
                   Prepended bb_ to function and table names to move this 
                   file into the Boot Block.
06/21/93   jah     Fixed bug in crc_16_l_calc().
06/07/93   jah     Added crc_16_l_calc().
04/20/93   jah     Added the table for an LSB-first CCITT-16 CRC.
07/09/92   jah     Changed crc_16_step() from bits to bytes
07/09/92   jah     Removed CRC generation program
06/21/92   jah     Created crc tables
06/18/92   jah     Ported from brassboard and converted to table-driven.

===========================================================================*/


/*===========================================================================

                     INCLUDE FILES FOR MODULE

===========================================================================*/

#include "jnand_crc.h"                /* CRC typedefs and definitions         */


/*===========================================================================

                DEFINITIONS AND DECLARATIONS FOR MODULE

This section contains definitions for constants, macros, types, variables
and other items needed by this module.

===========================================================================*/

/* The CRC table size is based on how many bits at a time we are going
** to process through the table.  Given that we are processing the data
** 8 bits at a time, this gives us 2^8 (256) entries.
*/
#define CRC_TAB_SIZE    256             /* 2^CRC_TAB_BITS      */

/* CRC table for 30 bit CRC, with generator polynomial 0x6030b9c7,
** calculated 8 bits at a time, MSB first.
*/
const dword crc30_table[ CRC_TAB_SIZE ] = {
  0x00000000, 0x2030b9c7, 0x2051ca49, 0x0061738e,
  0x20932d55, 0x00a39492, 0x00c2e71c, 0x20f25edb,
  0x2116e36d, 0x01265aaa, 0x01472924, 0x217790e3,
  0x0185ce38, 0x21b577ff, 0x21d40471, 0x01e4bdb6,
  0x221d7f1d, 0x022dc6da, 0x024cb554, 0x227c0c93,
  0x028e5248, 0x22beeb8f, 0x22df9801, 0x02ef21c6,
  0x030b9c70, 0x233b25b7, 0x235a5639, 0x036aeffe,
  0x2398b125, 0x03a808e2, 0x03c97b6c, 0x23f9c2ab,
  0x240a47fd, 0x043afe3a, 0x045b8db4, 0x246b3473,
  0x04996aa8, 0x24a9d36f, 0x24c8a0e1, 0x04f81926,
  0x051ca490, 0x252c1d57, 0x254d6ed9, 0x057dd71e,
  0x258f89c5, 0x05bf3002, 0x05de438c, 0x25eefa4b,
  0x061738e0, 0x26278127, 0x2646f2a9, 0x06764b6e,
  0x268415b5, 0x06b4ac72, 0x06d5dffc, 0x26e5663b,
  0x2701db8d, 0x0731624a, 0x075011c4, 0x2760a803,
  0x0792f6d8, 0x27a24f1f, 0x27c33c91, 0x07f38556,
  0x2824363d, 0x08148ffa, 0x0875fc74, 0x284545b3,
  0x08b71b68, 0x2887a2af, 0x28e6d121, 0x08d668e6,
  0x0932d550, 0x29026c97, 0x29631f19, 0x0953a6de,
  0x29a1f805, 0x099141c2, 0x09f0324c, 0x29c08b8b,
  0x0a394920, 0x2a09f0e7, 0x2a688369, 0x0a583aae,
  0x2aaa6475, 0x0a9addb2, 0x0afbae3c, 0x2acb17fb,
  0x2b2faa4d, 0x0b1f138a, 0x0b7e6004, 0x2b4ed9c3,
  0x0bbc8718, 0x2b8c3edf, 0x2bed4d51, 0x0bddf496,
  0x0c2e71c0, 0x2c1ec807, 0x2c7fbb89, 0x0c4f024e,
  0x2cbd5c95, 0x0c8de552, 0x0cec96dc, 0x2cdc2f1b,
  0x2d3892ad, 0x0d082b6a, 0x0d6958e4, 0x2d59e123,
  0x0dabbff8, 0x2d9b063f, 0x2dfa75b1, 0x0dcacc76,
  0x2e330edd, 0x0e03b71a, 0x0e62c494, 0x2e527d53,
  0x0ea02388, 0x2e909a4f, 0x2ef1e9c1, 0x0ec15006,
  0x0f25edb0, 0x2f155477, 0x2f7427f9, 0x0f449e3e,
  0x2fb6c0e5, 0x0f867922, 0x0fe70aac, 0x2fd7b36b,
  0x3078d5bd, 0x10486c7a, 0x10291ff4, 0x3019a633,
  0x10ebf8e8, 0x30db412f, 0x30ba32a1, 0x108a8b66,
  0x116e36d0, 0x315e8f17, 0x313ffc99, 0x110f455e,
  0x31fd1b85, 0x11cda242, 0x11acd1cc, 0x319c680b,
  0x1265aaa0, 0x32551367, 0x323460e9, 0x1204d92e,
  0x32f687f5, 0x12c63e32, 0x12a74dbc, 0x3297f47b,
  0x337349cd, 0x1343f00a, 0x13228384, 0x33123a43,
  0x13e06498, 0x33d0dd5f, 0x33b1aed1, 0x13811716,
  0x14729240, 0x34422b87, 0x34235809, 0x1413e1ce,
  0x34e1bf15, 0x14d106d2, 0x14b0755c, 0x3480cc9b,
  0x3564712d, 0x1554c8ea, 0x1535bb64, 0x350502a3,
  0x15f75c78, 0x35c7e5bf, 0x35a69631, 0x15962ff6,
  0x366fed5d, 0x165f549a, 0x163e2714, 0x360e9ed3,
  0x16fcc008, 0x36cc79cf, 0x36ad0a41, 0x169db386,
  0x17790e30, 0x3749b7f7, 0x3728c479, 0x17187dbe,
  0x37ea2365, 0x17da9aa2, 0x17bbe92c, 0x378b50eb,
  0x185ce380, 0x386c5a47, 0x380d29c9, 0x183d900e,
  0x38cfced5, 0x18ff7712, 0x189e049c, 0x38aebd5b,
  0x394a00ed, 0x197ab92a, 0x191bcaa4, 0x392b7363,
  0x19d92db8, 0x39e9947f, 0x3988e7f1, 0x19b85e36,
  0x3a419c9d, 0x1a71255a, 0x1a1056d4, 0x3a20ef13,
  0x1ad2b1c8, 0x3ae2080f, 0x3a837b81, 0x1ab3c246,
  0x1b577ff0, 0x3b67c637, 0x3b06b5b9, 0x1b360c7e,
  0x3bc452a5, 0x1bf4eb62, 0x1b9598ec, 0x3ba5212b,
  0x3c56a47d, 0x1c661dba, 0x1c076e34, 0x3c37d7f3,
  0x1cc58928, 0x3cf530ef, 0x3c944361, 0x1ca4faa6,
  0x1d404710, 0x3d70fed7, 0x3d118d59, 0x1d21349e,
  0x3dd36a45, 0x1de3d382, 0x1d82a00c, 0x3db219cb,
  0x1e4bdb60, 0x3e7b62a7, 0x3e1a1129, 0x1e2aa8ee,
  0x3ed8f635, 0x1ee84ff2, 0x1e893c7c, 0x3eb985bb,
  0x3f5d380d, 0x1f6d81ca, 0x1f0cf244, 0x3f3c4b83,
  0x1fce1558, 0x3ffeac9f, 0x3f9fdf11, 0x1faf66d6
};


/*===========================================================================

FUNCTION CRC_30_STEP

DESCRIPTION
  This function calculates a 30-bit CRC over a specified number of data
  bits.  It can be used to produce a CRC and to check a CRC.  The CRC value
  passed in is used to continue the CRC calculation from a previous call,
  this allows this routine to be used to CRC discontinuous data.

DEPENDENCIES
  None

RETURN VALUE
  Returns a double word holding 30 bits which are the contents of the
  CRC register as calculated over the specified data bits.  If this
  function is being used to check a CRC, then the return value will be
  equal to CRC_30_OK (defined in crc.h) if the CRC checks correctly.
  
  NOTE: The caller is expected to mask the bottom 30 bits from the value, 

SIDE EFFECTS
  None

===========================================================================*/

dword crc_30_step
(
  dword seed,
    /* Either the result of a previous crc_30_step() or CRC_16_STEP_SEED
    ** the first time the routine is called.  Note that the input is
    ** inverted prior to use, to counteract the inversion applied when
    ** it was returned as a result of the previous step.
    */

  byte *buf_ptr,
    /* Pointer to bytes containing the data to CRC.  The bit stream starts
    ** in the MS bit of the first byte.
    */

  word len
    /* Number of data bits to calculate the CRC over */
)
{
  dword data, crc_30;

  /* Generate a CRC-30 by looking up the transformation in a table and
  ** XOR-ing it into the CRC, one byte at a time.
  */
  for (crc_30 = ~seed & 0x3FFFFFFF; len >= 8; len -= 8, buf_ptr++) {
    crc_30 = crc30_table[ ((crc_30 >> (30 - 8)) ^ *buf_ptr) & 0xff ]
                ^ (crc_30 << 8);
  }

  /* Finish calculating the CRC over the trailing data bits
  **
  ** XOR the MS bit of data with the MS bit of the CRC.
  ** Shift the CRC and data left 1 bit.
  ** If the XOR result is 1, XOR the generating polynomial in with the CRC.
  */
  if (len != 0) {

    data = ((dword) (*buf_ptr)) << (30-8); /* Align data MSB with CRC MSB */

    while (len-- != 0) {
      if ( ((crc_30 ^ data) & (1L << 29)) != 0 ) {       /* Is MSB of XOR a 1 */

        crc_30 <<= 1;                   /* Left shift CRC          */
        crc_30 ^= CRC_30_POLYNOMIAL;    /* XOR polynomial into CRC */

      } else {

        crc_30 <<= 1;                   /* Left shift CRC          */

      }

      data <<= 1;                       /* Left shift data         */
    }
  }

  crc_30 = ~crc_30;                     /* 1's complement the CRC     */

  return( crc_30 & 0x3FFFFFFF );        /* mask the result to 30 bits */

} /* end of crc_30_calc */