ext/hal/silabs/gecko/emlib/src/em_gpcrc.c

/***************************************************************************//**
 * @file
 * @brief General Purpose Cyclic Redundancy Check (GPCRC) API.
 * @version 5.6.0
 *******************************************************************************
 * # License
 * <b>Copyright 2016 Silicon Laboratories, Inc. www.silabs.com</b>
 *******************************************************************************
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 *
 * DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Silicon Labs has no
 * obligation to support this Software. Silicon Labs is providing the
 * Software "AS IS", with no express or implied warranties of any kind,
 * including, but not limited to, any implied warranties of merchantability
 * or fitness for any particular purpose or warranties against infringement
 * of any proprietary rights of a third party.
 *
 * Silicon Labs will not be liable for any consequential, incidental, or
 * special damages, or any other relief, or for any claim by any third party,
 * arising from your use of this Software.
 *
 ******************************************************************************/

#include "em_common.h"
#include "em_gpcrc.h"
#include "em_assert.h"

#if defined(GPCRC_PRESENT) && (GPCRC_COUNT > 0)

/***************************************************************************//**
 * @addtogroup emlib
 * @{
 ******************************************************************************/

/***************************************************************************//**
 * @addtogroup GPCRC
 * @{
 ******************************************************************************/

/*******************************************************************************
 ***************************   GLOBAL FUNCTIONS   ******************************
 ******************************************************************************/

/***************************************************************************//**
 * @brief
 *   Initialize the General Purpose Cyclic Redundancy Check (GPCRC) module.
 *
 * @details
 *   Use this function to configure the operational parameters of the GPCRC,
 *   such as the polynomial to use and how the input should be preprocessed
 *   before entering the CRC calculation.
 *
 * @note
 *   This function will not copy the initialization value to the data register
 *   to prepare for a new CRC calculation. Either call
 *   @ref GPCRC_Start before each calculation or by use the
 *   autoInit functionality.
 *
 * @param[in] gpcrc
 *   A pointer to the GPCRC peripheral register block.
 *
 * @param[in] init
 *   A pointer to the initialization structure used to configure the GPCRC.
 ******************************************************************************/
void GPCRC_Init(GPCRC_TypeDef * gpcrc, const GPCRC_Init_TypeDef * init)
{
  uint32_t polySelect;
  uint32_t revPoly = 0;

  if (init->crcPoly == 0x04C11DB7) {
    polySelect = GPCRC_CTRL_POLYSEL_CRC32;
  } else {
    // If not using the fixed CRC-32 polynomial, use 16-bit.
    EFM_ASSERT((init->crcPoly & 0xFFFF0000) == 0);
#if defined(GPCRC_CTRL_POLYSEL_CRC16)
    polySelect = GPCRC_CTRL_POLYSEL_CRC16;
#else
    polySelect = GPCRC_CTRL_POLYSEL_16;
#endif
    revPoly = SL_RBIT16(init->crcPoly);
  }

#if defined(GPCRC_EN_EN)
  if (init->enable) {
    gpcrc->EN_SET = GPCRC_EN_EN;
  } else {
    gpcrc->EN_CLR = GPCRC_EN_EN;
  }

  gpcrc->CTRL = (((uint32_t)init->autoInit << _GPCRC_CTRL_AUTOINIT_SHIFT)
                 | ((uint32_t)init->reverseByteOrder << _GPCRC_CTRL_BYTEREVERSE_SHIFT)
                 | ((uint32_t)init->reverseBits << _GPCRC_CTRL_BITREVERSE_SHIFT)
                 | ((uint32_t)init->enableByteMode << _GPCRC_CTRL_BYTEMODE_SHIFT)
                 | polySelect);
#else
  gpcrc->CTRL = (((uint32_t)init->autoInit << _GPCRC_CTRL_AUTOINIT_SHIFT)
                 | ((uint32_t)init->reverseByteOrder << _GPCRC_CTRL_BYTEREVERSE_SHIFT)
                 | ((uint32_t)init->reverseBits << _GPCRC_CTRL_BITREVERSE_SHIFT)
                 | ((uint32_t)init->enableByteMode << _GPCRC_CTRL_BYTEMODE_SHIFT)
                 | polySelect
                 | ((uint32_t)init->enable << _GPCRC_CTRL_EN_SHIFT));
#endif

#if defined(GPCRC_CTRL_POLYSEL_CRC16)
  if (polySelect == GPCRC_CTRL_POLYSEL_CRC16) {
#else
  if (polySelect == GPCRC_CTRL_POLYSEL_16) {
#endif
    // Set the CRC polynomial value.
    gpcrc->POLY = revPoly & _GPCRC_POLY_POLY_MASK;
  }

  // Load the CRC initialization value to GPCRC_INIT.
  gpcrc->INIT = init->initValue;
}

/***************************************************************************//**
 * @brief
 *   Reset GPCRC registers to the hardware reset state.
 *
 * @note
 *   The data registers are not reset by this function.
 *
 * @param[in] gpcrc
 *   A pointer to the GPCRC peripheral register block.
 ******************************************************************************/
void GPCRC_Reset(GPCRC_TypeDef * gpcrc)
{
  gpcrc->CTRL = _GPCRC_CTRL_RESETVALUE;
  gpcrc->POLY = _GPCRC_POLY_RESETVALUE;
  gpcrc->INIT = _GPCRC_INIT_RESETVALUE;
}

/** @} (end addtogroup GPCRC) */
/** @} (end addtogroup emlib) */

#endif /* defined(GPCRC_COUNT) && (GPCRC_COUNT > 0) */