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* Copyright (c) 2015-2016, Freescale Semiconductor, Inc.
* Copyright 2016-2017 NXP
* All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include "fsl_crc.h"
/*******************************************************************************
* Definitions
******************************************************************************/
/*! @internal @brief Has data register with name CRC. */
#if defined(FSL_FEATURE_CRC_HAS_CRC_REG) && FSL_FEATURE_CRC_HAS_CRC_REG
#define DATA CRC
#define DATALL CRCLL
#endif
#if defined(CRC_DRIVER_USE_CRC16_CCIT_FALSE_AS_DEFAULT) && CRC_DRIVER_USE_CRC16_CCIT_FALSE_AS_DEFAULT
/* @brief Default user configuration structure for CRC-16-CCITT */
#define CRC_DRIVER_DEFAULT_POLYNOMIAL 0x1021U
/*< CRC-16-CCIT polynomial x**16 + x**12 + x**5 + x**0 */
#define CRC_DRIVER_DEFAULT_SEED 0xFFFFU
/*< Default initial checksum */
#define CRC_DRIVER_DEFAULT_REFLECT_IN false
/*< Default is no transpose */
#define CRC_DRIVER_DEFAULT_REFLECT_OUT false
/*< Default is transpose bytes */
#define CRC_DRIVER_DEFAULT_COMPLEMENT_CHECKSUM false
/*< Default is without complement of CRC data register read data */
#define CRC_DRIVER_DEFAULT_CRC_BITS kCrcBits16
/*< Default is 16-bit CRC protocol */
#define CRC_DRIVER_DEFAULT_CRC_RESULT kCrcFinalChecksum
/*< Default is resutl type is final checksum */
#endif /* CRC_DRIVER_USE_CRC16_CCIT_FALSE_AS_DEFAULT */
/*! @brief CRC type of transpose of read write data */
typedef enum _crc_transpose_type
{
kCrcTransposeNone = 0U, /*! No transpose */
kCrcTransposeBits = 1U, /*! Tranpose bits in bytes */
kCrcTransposeBitsAndBytes = 2U, /*! Transpose bytes and bits in bytes */
kCrcTransposeBytes = 3U, /*! Transpose bytes */
} crc_transpose_type_t;
/*!
* @brief CRC module configuration.
*
* This structure holds the configuration for the CRC module.
*/
typedef struct _crc_module_config
{
uint32_t polynomial; /*!< CRC Polynomial, MSBit first.@n
Example polynomial: 0x1021 = 1_0000_0010_0001 = x^12+x^5+1 */
uint32_t seed; /*!< Starting checksum value */
crc_transpose_type_t readTranspose; /*!< Type of transpose when reading CRC result. */
crc_transpose_type_t writeTranspose; /*!< Type of transpose when writing CRC input data. */
bool complementChecksum; /*!< True if the result shall be complement of the actual checksum. */
crc_bits_t crcBits; /*!< Selects 16- or 32- bit CRC protocol. */
} crc_module_config_t;
/*******************************************************************************
* Code
******************************************************************************/
/*!
* @brief Returns transpose type for CRC protocol reflect in parameter.
*
* This functions helps to set writeTranspose member of crc_config_t structure. Reflect in is CRC protocol parameter.
*
* @param enable True or false for the selected CRC protocol Reflect In (refin) parameter.
*/
static inline crc_transpose_type_t CRC_GetTransposeTypeFromReflectIn(bool enable)
{
return ((enable) ? kCrcTransposeBitsAndBytes : kCrcTransposeBytes);
}
/*!
* @brief Returns transpose type for CRC protocol reflect out parameter.
*
* This functions helps to set readTranspose member of crc_config_t structure. Reflect out is CRC protocol parameter.
*
* @param enable True or false for the selected CRC protocol Reflect Out (refout) parameter.
*/
static inline crc_transpose_type_t CRC_GetTransposeTypeFromReflectOut(bool enable)
{
return ((enable) ? kCrcTransposeBitsAndBytes : kCrcTransposeNone);
}
/*!
* @brief Starts checksum computation.
*
* Configures the CRC module for the specified CRC protocol. @n
* Starts the checksum computation by writing the seed value
*
* @param base CRC peripheral address.
* @param config Pointer to protocol configuration structure.
*/
static void CRC_ConfigureAndStart(CRC_Type *base, const crc_module_config_t *config)
{
uint32_t crcControl;
/* pre-compute value for CRC control registger based on user configuraton without WAS field */
crcControl = 0 | CRC_CTRL_TOT(config->writeTranspose) | CRC_CTRL_TOTR(config->readTranspose) |
CRC_CTRL_FXOR(config->complementChecksum) | CRC_CTRL_TCRC(config->crcBits);
/* make sure the control register is clear - WAS is deasserted, and protocol is set */
base->CTRL = crcControl;
/* write polynomial register */
base->GPOLY = config->polynomial;
/* write pre-computed control register value along with WAS to start checksum computation */
base->CTRL = crcControl | CRC_CTRL_WAS(true);
/* write seed (initial checksum) */
base->DATA = config->seed;
/* deassert WAS by writing pre-computed CRC control register value */
base->CTRL = crcControl;
}
/*!
* @brief Starts final checksum computation.
*
* Configures the CRC module for the specified CRC protocol. @n
* Starts final checksum computation by writing the seed value.
* @note CRC_Get16bitResult() or CRC_Get32bitResult() return final checksum
* (output reflection and xor functions are applied).
*
* @param base CRC peripheral address.
* @param protocolConfig Pointer to protocol configuration structure.
*/
static void CRC_SetProtocolConfig(CRC_Type *base, const crc_config_t *protocolConfig)
{
crc_module_config_t moduleConfig;
/* convert protocol to CRC peripheral module configuration, prepare for final checksum */
moduleConfig.polynomial = protocolConfig->polynomial;
moduleConfig.seed = protocolConfig->seed;
moduleConfig.readTranspose = CRC_GetTransposeTypeFromReflectOut(protocolConfig->reflectOut);
moduleConfig.writeTranspose = CRC_GetTransposeTypeFromReflectIn(protocolConfig->reflectIn);
moduleConfig.complementChecksum = protocolConfig->complementChecksum;
moduleConfig.crcBits = protocolConfig->crcBits;
CRC_ConfigureAndStart(base, &moduleConfig);
}
/*!
* @brief Starts intermediate checksum computation.
*
* Configures the CRC module for the specified CRC protocol. @n
* Starts intermediate checksum computation by writing the seed value.
* @note CRC_Get16bitResult() or CRC_Get32bitResult() return intermediate checksum (raw data register value).
*
* @param base CRC peripheral address.
* @param protocolConfig Pointer to protocol configuration structure.
*/
static void CRC_SetRawProtocolConfig(CRC_Type *base, const crc_config_t *protocolConfig)
{
crc_module_config_t moduleConfig;
/* convert protocol to CRC peripheral module configuration, prepare for intermediate checksum */
moduleConfig.polynomial = protocolConfig->polynomial;
moduleConfig.seed = protocolConfig->seed;
moduleConfig.readTranspose =
kCrcTransposeNone; /* intermediate checksum does no transpose of data register read value */
moduleConfig.writeTranspose = CRC_GetTransposeTypeFromReflectIn(protocolConfig->reflectIn);
moduleConfig.complementChecksum = false; /* intermediate checksum does no xor of data register read value */
moduleConfig.crcBits = protocolConfig->crcBits;
CRC_ConfigureAndStart(base, &moduleConfig);
}
void CRC_Init(CRC_Type *base, const crc_config_t *config)
{
#if !(defined(FSL_SDK_DISABLE_DRIVER_CLOCK_CONTROL) && FSL_SDK_DISABLE_DRIVER_CLOCK_CONTROL)
/* ungate clock */
CLOCK_EnableClock(kCLOCK_Crc0);
#endif /* FSL_SDK_DISABLE_DRIVER_CLOCK_CONTROL */
/* configure CRC module and write the seed */
if (config->crcResult == kCrcFinalChecksum)
{
CRC_SetProtocolConfig(base, config);
}
else
{
CRC_SetRawProtocolConfig(base, config);
}
}
void CRC_GetDefaultConfig(crc_config_t *config)
{
static const crc_config_t crc16ccit = {
CRC_DRIVER_DEFAULT_POLYNOMIAL, CRC_DRIVER_DEFAULT_SEED,
CRC_DRIVER_DEFAULT_REFLECT_IN, CRC_DRIVER_DEFAULT_REFLECT_OUT,
CRC_DRIVER_DEFAULT_COMPLEMENT_CHECKSUM, CRC_DRIVER_DEFAULT_CRC_BITS,
CRC_DRIVER_DEFAULT_CRC_RESULT,
};
*config = crc16ccit;
}
void CRC_WriteData(CRC_Type *base, const uint8_t *data, size_t dataSize)
{
const uint32_t *data32;
/* 8-bit reads and writes till source address is aligned 4 bytes */
while ((dataSize) && ((uint32_t)data & 3U))
{
base->ACCESS8BIT.DATALL = *data;
data++;
dataSize--;
}
/* use 32-bit reads and writes as long as possible */
data32 = (const uint32_t *)data;
while (dataSize >= sizeof(uint32_t))
{
base->DATA = *data32;
data32++;
dataSize -= sizeof(uint32_t);
}
data = (const uint8_t *)data32;
/* 8-bit reads and writes till end of data buffer */
while (dataSize)
{
base->ACCESS8BIT.DATALL = *data;
data++;
dataSize--;
}
}
uint32_t CRC_Get32bitResult(CRC_Type *base)
{
return base->DATA;
}
uint16_t CRC_Get16bitResult(CRC_Type *base)
{
uint32_t retval;
uint32_t totr; /* type of transpose read bitfield */
retval = base->DATA;
totr = (base->CTRL & CRC_CTRL_TOTR_MASK) >> CRC_CTRL_TOTR_SHIFT;
/* check transpose type to get 16-bit out of 32-bit register */
if (totr >= 2U)
{
/* transpose of bytes for read is set, the result CRC is in CRC_DATA[HU:HL] */
retval &= 0xFFFF0000U;
retval = retval >> 16U;
}
else
{
/* no transpose of bytes for read, the result CRC is in CRC_DATA[LU:LL] */
retval &= 0x0000FFFFU;
}
return (uint16_t)retval;
}
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