File content as of revision 171:3a7713b1edbc:

/**
 * \file
 *
 * \brief SAM DMA cyclic redundancy check (CRC) Driver
 *
 * Copyright (C) 2014-2015 Atmel Corporation. All rights reserved.
 *
 * \asf_license_start
 *
 * \page License
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * 3. The name of Atmel may not be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * 4. This software may only be redistributed and used in connection with an
 *    Atmel microcontroller product.
 *
 * 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
 * EXPRESSLY AND SPECIFICALLY 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.
 *
 * \asf_license_stop
 *
 */
/*
 * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
 */
#ifndef DMA_CRC_H_INCLUDED
#define DMA_CRC_H_INCLUDED

#include <compiler.h>

#ifdef __cplusplus
extern "C" {
#endif

/** DMA channel n offset. */
#define DMA_CRC_CHANNEL_N_OFFSET 0x20

/** CRC Polynomial Type. */
enum crc_polynomial_type {
    /** CRC16 (CRC-CCITT). */
    CRC_TYPE_16,
    /** CRC32 (IEEE 802.3). */
    CRC_TYPE_32,
};

/** CRC Beat Type. */
enum crc_beat_size {
    /** Byte bus access. */
    CRC_BEAT_SIZE_BYTE,
    /** Half-word bus access. */
    CRC_BEAT_SIZE_HWORD,
    /** Word bus access. */
    CRC_BEAT_SIZE_WORD,
};

/** Configurations for CRC calculation. */
struct dma_crc_config {
    /** CRC polynomial type. */
    enum crc_polynomial_type type;
    /** CRC beat size. */
    enum crc_beat_size size;
};

/**
 * \brief Get DMA CRC default configurations.
 *
 * The default configuration is as follows:
 *  \li Polynomial type is set to CRC-16(CRC-CCITT)
 *  \li CRC Beat size: BYTE
 *
 * \param[in] config default configurations
 */
static inline void dma_crc_get_config_defaults(struct dma_crc_config *config)
{
    Assert(config);

    config->type = CRC_TYPE_16;
    config->size = CRC_BEAT_SIZE_BYTE;
}

/**
 * \brief Enable DMA CRC module with an DMA channel.
 *
 * This function enables a CRC calculation with an allocated DMA channel. This channel ID
 * can be gotten from a successful \ref dma_allocate.
 *
 * \param[in] channel_id DMA channel expected with CRC calculation
 * \param[in] config CRC calculation configurations
 *
 * \return Status of the DMC CRC.
 * \retval STATUS_OK Get the DMA CRC module
 * \retval STATUS_BUSY DMA CRC module is already taken and not ready yet
 */
static inline enum status_code dma_crc_channel_enable(uint32_t channel_id,
        struct dma_crc_config *config)
{
    if (DMAC->CRCSTATUS.reg & DMAC_CRCSTATUS_CRCBUSY) {
        return STATUS_BUSY;
    }

    DMAC->CRCCTRL.reg = DMAC_CRCCTRL_CRCBEATSIZE(config->size) |
                        DMAC_CRCCTRL_CRCPOLY(config->type) |
                        DMAC_CRCCTRL_CRCSRC(channel_id+DMA_CRC_CHANNEL_N_OFFSET);

    DMAC->CTRL.reg |= DMAC_CTRL_CRCENABLE;

    return STATUS_OK;
}

/**
 * \brief Disable DMA CRC module.
 *
 */
static inline void dma_crc_disable(void)
{
    DMAC->CTRL.reg &= ~DMAC_CTRL_CRCENABLE;
    DMAC->CRCCTRL.reg = 0;
}

/**
 * \brief Get DMA CRC checksum value.
 *
 * \return Calculated CRC checksum.
 */
static inline uint32_t dma_crc_get_checksum(void)
{
    if (DMAC->CRCCTRL.bit.CRCSRC == DMAC_CRCCTRL_CRCSRC_IO_Val) {
        DMAC->CRCSTATUS.reg = DMAC_CRCSTATUS_CRCBUSY;
    }

    return DMAC->CRCCHKSUM.reg;
}

/**
 * \brief Enable DMA CRC module with I/O.
 *
 * This function enables a CRC calculation with I/O mode.
 *
 * \param[in] config CRC calculation configurations.
 *
 * \return Status of the DMC CRC.
 * \retval STATUS_OK Get the DMA CRC module
 * \retval STATUS_BUSY DMA CRC module is already taken and not ready yet
 */
static inline enum status_code dma_crc_io_enable(
    struct dma_crc_config *config)
{
    if (DMAC->CRCSTATUS.reg & DMAC_CRCSTATUS_CRCBUSY) {
        return STATUS_BUSY;
    }

    if (DMAC->CTRL.reg & DMAC_CTRL_CRCENABLE) {
        return STATUS_BUSY;
    }

    DMAC->CRCCTRL.reg = DMAC_CRCCTRL_CRCBEATSIZE(config->size) |
                        DMAC_CRCCTRL_CRCPOLY(config->type) |
                        DMAC_CRCCTRL_CRCSRC_IO;

    if (config->type == CRC_TYPE_32) {
        DMAC->CRCCHKSUM.reg = 0xFFFFFFFF;
    }

    DMAC->CTRL.reg |= DMAC_CTRL_CRCENABLE;

    return STATUS_OK;
}

/**
 * \brief Calculate CRC with I/O.
 *
 * This function calculate the CRC of the input data buffer.
 *
 * \param[in] buffer CRC Pointer to calculation buffer
 * \param[in] total_beat_size Total beat size to be calculated
 *
 * \return Calculated CRC checksum value.
 */
static inline void dma_crc_io_calculation(void *buffer,
        uint32_t total_beat_size)
{
    uint32_t counter = total_beat_size;
    uint8_t *buffer_8;
    uint16_t *buffer_16;
    uint32_t *buffer_32;

    for (counter=0; counter<total_beat_size; counter++) {
        if (DMAC->CRCCTRL.bit.CRCBEATSIZE == CRC_BEAT_SIZE_BYTE) {
            buffer_8 = buffer;
            DMAC->CRCDATAIN.reg = buffer_8[counter];
        } else if (DMAC->CRCCTRL.bit.CRCBEATSIZE == CRC_BEAT_SIZE_HWORD) {
            buffer_16 = buffer;
            DMAC->CRCDATAIN.reg = buffer_16[counter];
        } else if (DMAC->CRCCTRL.bit.CRCBEATSIZE == CRC_BEAT_SIZE_WORD) {
            buffer_32 = buffer;
            DMAC->CRCDATAIN.reg = buffer_32[counter];
        }
        /* Wait several cycle to make sure CRC complete */
        nop();
        nop();
        nop();
        nop();
    }
}

#ifdef __cplusplus
}
#endif

#endif /* DMA_CRC_H_INCLUDED */