FreeRTOS/Demo/CORTEX_A5_SAMA5D2x_Xplained_IAR/AtmelFiles/drivers/peripherals/tdes.c

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/** \addtogroup tdes_module Working with TDES
 * \ingroup peripherals_module
 * The TDES driver provides the interface to configure and use the TDES
 * peripheral.
 * \n
 *
 * The Data Encryption Standard (DES) and the Triple Data Encryption Algorithm
 * (TDES) specify FIPS-approved cryptographic algorithms that can be used to
 * protect electronic data.
 * The TDES bit in the TDES Mode Register (TDES_MR) is used to select either the
 * single DES or the Triple DES mode (make use of the tdes_configure()
 * function).
 *
 * The DES uses 64-bit cryptographic keys to encrypt and decrypt 64-bit data
 * blocks. Input data can be fed calling tdes_set_input().
 * The 64-bit key is defined in the Key 1 Word Registers (TDES_KEY1WRx) and set
 * by tdes_write_key1().
 *
 * The Triple DES key consists in three DES keys, which set is also referred to
 * as a key bundle. These three 64-bit keys are defined, respectively, in the
 * Key 1, 2 and 3 Word Registers (TDES_KEY1WRx, TDES_KEY2WRx and TDES_KEY3WRx).
 * In Triple DES mode (TDES_MR:TDESMOD set to 1), the TDES_MR:KEYMOD bit is used
 * to select either the two- or three-key algorithm.
 *
 * In order to perform TDES encryption/decryption, the user has to follow these
 * few steps:
 * <ul>
 * <li> A software-triggered hardware reset of the TDES interface is performed
 * by tdes_soft_reset().</li>
 * <li> Configure TDES algorithm mode, key mode, start mode and operation mode
 * by means of tdes_configure().</li>
 * <li> Set DES keys with function tdes_write_key1(), tdes_write_key2(), and
 * tdes_write_key3().</li>
 * <li> To start encrypting or decrypting call tdes_start().</li>
 * <li> Retrieve the encryption or decryption result by means of
 * tdes_get_output().</li>
 * </ul>
 *
 * For more accurate information, please look at the TDES section of the
 * Datasheet.
 *
 * Related files:\n
 * \ref tdes.c\n
 * \ref tdes.h\n
 */
/*@{*/
/*@}*/
/**
 * \file
 *
 * Implementation of the Triple Data Encryption Algorithm (TDES).
 *
 */

/*----------------------------------------------------------------------------
 *        Headers
 *----------------------------------------------------------------------------*/

#include "chip.h"
#include "peripherals/tdes.h"

/*----------------------------------------------------------------------------
 *        Exported functions
 *----------------------------------------------------------------------------*/

void tdes_start(void)
{
	TDES->TDES_CR = TDES_CR_START;
}

void tdes_soft_reset(void)
{
	TDES->TDES_CR = TDES_CR_SWRST;
}

void tdes_configure(uint32_t mode)
{
	TDES->TDES_MR = mode;
}

void tdes_enable_it(uint32_t sources)
{
	TDES->TDES_IER = sources;
}

void tdes_disable_it(uint32_t sources)
{
	TDES->TDES_IDR = sources;
}

uint32_t tdes_get_status(void)
{
	return TDES->TDES_ISR;
}

void tdes_write_key1(uint32_t key_word0, uint32_t key_word1)
{
	TDES->TDES_KEY1WR[0] = key_word0;
	TDES->TDES_KEY1WR[1] = key_word1;
}

void tdes_write_key2(uint32_t key_word0, uint32_t key_word1)
{
	TDES->TDES_KEY2WR[0] = key_word0;
	TDES->TDES_KEY2WR[1] = key_word1;
}

void tdes_write_key3(uint32_t key_word0, uint32_t key_word1)
{
	TDES->TDES_KEY3WR[0] = key_word0;
	TDES->TDES_KEY3WR[1] = key_word1;
}

void tdes_set_input(uint32_t data0, uint32_t data1)
{
	TDES->TDES_IDATAR[0] = data0;
	TDES->TDES_IDATAR[1] = data1;
}

void tdes_get_output(uint32_t *data0, uint32_t *data1)
{
	*data0 = TDES->TDES_ODATAR[0];
	*data1 = TDES->TDES_ODATAR[1];
}

void tdes_set_vector(uint32_t v0, uint32_t v1)
{
	TDES->TDES_IVR[0] = v0;
	TDES->TDES_IVR[1] = v1;
}

void tdes_set_xtea_rounds(uint32_t rounds)
{
	TDES->TDES_XTEA_RNDR = TDES_XTEA_RNDR_XTEA_RNDS(rounds);
}