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/* ----------------------------------------------------------------------------

 *         ATMEL Microcontroller Software Support

 * ----------------------------------------------------------------------------

 * Copyright (c) 2008, Atmel Corporation

 *

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 * - Redistributions of source code must retain the above copyright notice,

 * this list of conditions and the disclaimer below.

 *

 * Atmel's name may not be used to endorse or promote products derived from

 * this software without specific prior written permission.

 *

 * DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF

 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE

 * DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,

 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,

 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 * ----------------------------------------------------------------------------

 */

//------------------------------------------------------------------------------

//         Headers

//------------------------------------------------------------------------------

#include "aes.h"

#include <board.h>

#include <utility/trace.h>

#include <utility/assert.h>

//------------------------------------------------------------------------------

//         Global functions

//------------------------------------------------------------------------------

//------------------------------------------------------------------------------

/// Configures the AES peripheral to encrypt/decrypt, start mode (manual, auto,

/// PDC) and operating mode (ECB, CBC, OFB, CFB, CTR).

/// \param cipher  Indicates if the peripheral should encrypt or decrypt data.

/// \param smode  Start mode.

/// \param opmode  Operating mode.

//------------------------------------------------------------------------------

void AES_Configure(

    unsigned char cipher,

    unsigned int smode,

    unsigned int opmode)

{

    TRACE_DEBUG("AES_Configure()\n\r");

    SANITY_CHECK((cipher & 0xFFFFFFFE) == 0);

    SANITY_CHECK((smode & 0xFFFFFCFF) == 0);

    SANITY_CHECK((opmode & 0xFFFF8FFF) == 0);

    // Reset the peripheral first

    AT91C_BASE_AES->AES_CR = AT91C_AES_SWRST;

    // Configure mode register

    AT91C_BASE_AES->AES_MR = cipher | smode | opmode;

}

//------------------------------------------------------------------------------

/// Sets the key used by the AES algorithm to cipher the plain text or

/// decipher the encrypted text.

/// \param pKey  Pointer to a 16-bytes cipher key.

//------------------------------------------------------------------------------

void AES_SetKey(const unsigned int *pKey)

{

    TRACE_DEBUG("AES_SetKey()\n\r");

    SANITY_CHECK(pKey);

    AT91C_BASE_AES->AES_KEYWxR[0] = pKey[0];

    AT91C_BASE_AES->AES_KEYWxR[1] = pKey[1];

    AT91C_BASE_AES->AES_KEYWxR[2] = pKey[2];

    AT91C_BASE_AES->AES_KEYWxR[3] = pKey[3];

}

//------------------------------------------------------------------------------

/// Sets the initialization vector that is used to encrypt the plain text or

/// decrypt the cipher text in chained block modes (CBC, CFB, OFB & CTR).

/// \param pVector  Pointer to a 16-bytes initialization vector.

//------------------------------------------------------------------------------

void AES_SetVector(const unsigned int *pVector)

{

    TRACE_DEBUG("AES_SetVector()\n\r");

    SANITY_CHECK(pVector);

    AT91C_BASE_AES->AES_IVxR[0] = pVector[0];

    AT91C_BASE_AES->AES_IVxR[1] = pVector[1];

    AT91C_BASE_AES->AES_IVxR[2] = pVector[2];

    AT91C_BASE_AES->AES_IVxR[3] = pVector[3];

}

//------------------------------------------------------------------------------

/// Sets the input data of the AES algorithm (i.e. plain text in cipher mode,

/// ciphered text in decipher mode). If auto mode is active, the encryption is

/// started automatically after writing the last word.

/// \param pData  Pointer to the 16-bytes data to cipher/decipher.

//------------------------------------------------------------------------------

void AES_SetInputData(const unsigned int *pData)

{

    TRACE_DEBUG("AES_SetInputData()\n\r");

    SANITY_CHECK(pData);

    AT91C_BASE_AES->AES_IDATAxR[0] = pData[0];

    AT91C_BASE_AES->AES_IDATAxR[1] = pData[1];

    AT91C_BASE_AES->AES_IDATAxR[2] = pData[2];

    AT91C_BASE_AES->AES_IDATAxR[3] = pData[3];

}

//------------------------------------------------------------------------------

/// Stores the result of the last AES operation (encrypt/decrypt) in the

/// provided buffer.

/// \param pData  Pointer to a 16-bytes buffer.

//------------------------------------------------------------------------------

void AES_GetOutputData(unsigned int *pData)

{

    TRACE_DEBUG("AES_GetOutputData()\n\r");

    SANITY_CHECK(pData);

    pData[0] = AT91C_BASE_AES->AES_ODATAxR[0];

    pData[1] = AT91C_BASE_AES->AES_ODATAxR[1];

    pData[2] = AT91C_BASE_AES->AES_ODATAxR[2];

    pData[3] = AT91C_BASE_AES->AES_ODATAxR[3];

}

//------------------------------------------------------------------------------

/// Sets the input buffer to use when in PDC mode.

/// \param pInput  Pointer to the input buffer.

//------------------------------------------------------------------------------

void AES_SetInputBuffer(const unsigned int *pInput)

{

    TRACE_DEBUG("AES_SetInputBuffer()\n\r");

    SANITY_CHECK(pInput);

    AT91C_BASE_AES->AES_TPR = (unsigned int) pInput;

    AT91C_BASE_AES->AES_TCR = 4;

}

//------------------------------------------------------------------------------

/// Sets the output buffer to use when in PDC mode.

/// \param pOutput  Pointer to the output buffer.

//------------------------------------------------------------------------------

void AES_SetOutputBuffer(unsigned int *pOutput)

{

    TRACE_DEBUG("AES_SetOutputBuffer()\n\r");

    SANITY_CHECK(pOutput);

    AT91C_BASE_AES->AES_RPR = (unsigned int) pOutput;

    AT91C_BASE_AES->AES_RCR = 4;

}

//------------------------------------------------------------------------------

/// Starts the encryption/decryption process when in manual or PDC mode. In

/// manual mode, the key and input data must have been entered using

/// AES_SetKey() and AES_SetInputData(). In PDC mode, the key, input & output

/// buffer must have been set using AES_SetKey(), AES_SetInputBuffer() and

/// AES_SetOutputBuffer().

//------------------------------------------------------------------------------

void AES_Start(void)

{

    TRACE_DEBUG("AES_Start()\n\r");

    SANITY_CHECK(((AT91C_BASE_AES->AES_MR & AT91C_AES_SMOD) == AT91C_AES_SMOD_MANUAL)

                 || ((AT91C_BASE_AES->AES_MR & AT91C_AES_SMOD) == AT91C_AES_SMOD_PDC));

    // Manual mode

    if ((AT91C_BASE_AES->AES_MR & AT91C_AES_SMOD) == AT91C_AES_SMOD_MANUAL) {

        AT91C_BASE_AES->AES_CR = AT91C_AES_START;

    }

    // PDC

    else {

        AT91C_BASE_AES->AES_PTCR = AT91C_PDC_RXTEN | AT91C_PDC_TXTEN;

    }

}

//------------------------------------------------------------------------------

/// Returns the current value of the AES interrupt status register.

//------------------------------------------------------------------------------

unsigned int AES_GetStatus(void)

{

    TRACE_DEBUG("AES_GetStatus()\n\r");

    return AT91C_BASE_AES->AES_ISR;

}