jnand_crc.h

QUALCOMM JNAND DRIVER

#ifndef __JNAND_CRC_H__
#define __JNAND_CRC_H__
/*===========================================================================

              C R C    S E R V I C E S    D E C L A R A T I O N S

DESCRIPTION
  The following declarations are for use with the CRC Services.

Copyright(c) 1991,1992,1996 by QUALCOMM, Incorporated.  All Rights Reserved.
Copyright(c) 1998,1999      by QUALCOMM, Incorporated.  All Rights Reserved.
===========================================================================*/


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

                      EDIT HISTORY FOR FILE

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

$Header: //depot/asic/MSMSHARED/tools/jnand/jnand_crc.h#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 references.
11/29/01   lad     Added step-wise CRC30 calculation.
03/17/99   ms      Removed comments related to bb_ for Virtual Boot Block.
12/16/98   jct     Removed 80186 support
09/21/98   jct     Incorporate ARM porting changes, cdecl changes
02/28/96   dna     Changed crc_16_l_table extern to be a pointer so the 
                   macro now accesses the table through the Boot Block jump
                   table.
06/21/93   jah     Corrected CRC_16_L_OK to match with crc_16_l_calc().
06/07/93   jah     Added prototype for crc_16_l_calc(), and improved comments
                   for CRC_16_L_STEP().
04/26/93   jah     Added extern for crc_16_l_table[] for macro.
04/22/93   jah     Added CRC definitions and macro to support CRC CCITT-16
                   processed LSB first.
07/09/92   jah     Changed crc_16_step() from bits to bytes
06/18/92   jah     Ported from brassboard and converted to table-driven.

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

#include "jnand_comdef.h"


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

                        DATA DECLARATIONS

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


/* Residual CRC value to compare against return value of crc_30_calc().
** Use crc_30_calc() to calculate a 30 bit CRC, and append it to the buffer.
** When crc_30_calc() is applied to the unchanged result, it returns CRC_30_OK.
*/
#define  CRC_30_OK  0x0B105AA5

/* Mask for CRC-30 polynomial:
**
**      x^30+x^29+x^21+x^20+x^15+x^13+x^12+x^11+x^8+x^7+x^6+x^2+x^1+1
**
** Note:  the x^30 tap is left off, it's implicit.
*/
#define CRC_30_POLYNOMIAL       0x6030B9C7

/* Seed value for CRC register.  The all ones seed allows detection of
** an entire data stream of zeroes.
*/
#define CRC_30_SEED             0x3FFFFFFF

/* Seed value for CRC30 register.  The CRC30 seed is inverted prior to
** being used in the step-wise CRC-30.  This behaves as CRC_30_SEED.
*/
#define CRC_30_STEP_SEED        (~((dword) CRC_30_SEED))

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

                      FUNCTION DECLARATIONS

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



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

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

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

extern 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 */
);

#endif /* __JNAND_CRC_H__ */