xref: /FreeRTOS-Plus-TCP-v4.0.0/source/portable/NetworkInterface/ATSAM4E/gmac.c (revision 245d5879903cfc6e52a466fc1067fe54f869740c)

/**
 * \file
 *
 * \brief GMAC (Ethernet MAC) driver for SAM.
 *
 * Copyright (c) 2013 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
 *
 */

/* Standard includes. */
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

/* FreeRTOS includes. */
#include "FreeRTOS.h"
#include "task.h"

#include "FreeRTOSIPConfig.h"

#include "compiler.h"
#include "instance/gmac.h"
#include "ethernet_phy.h"

/*/ @cond 0 */
/**INDENT-OFF**/
#ifdef __cplusplus
    extern "C" {
#endif
/**INDENT-ON**/
/*/ @endcond */

#ifndef ARRAY_SIZE
    #define ARRAY_SIZE( x )    ( int ) ( sizeof( x ) / sizeof( x )[ 0 ] )
#endif

/**
 * \defgroup gmac_group Ethernet Media Access Controller
 *
 * See \ref gmac_quickstart.
 *
 * Driver for the GMAC (Ethernet Media Access Controller).
 * This file contains basic functions for the GMAC, with support for all modes, settings
 * and clock speeds.
 *
 * \section dependencies Dependencies
 * This driver does not depend on other modules.
 *
 * @{
 */

/** TX descriptor lists */
COMPILER_ALIGNED( 8 )
static gmac_tx_descriptor_t gs_tx_desc[ GMAC_TX_BUFFERS ];
#if ( GMAC_USES_TX_CALLBACK != 0 )
/** TX callback lists */
    static gmac_dev_tx_cb_t gs_tx_callback[ GMAC_TX_BUFFERS ];
#endif
/** RX descriptors lists */
COMPILER_ALIGNED( 8 )
static gmac_rx_descriptor_t gs_rx_desc[ GMAC_RX_BUFFERS ];

#if ( ipconfigZERO_COPY_TX_DRIVER == 0 )

/** Send Buffer. Section 3.6 of AMBA 2.0 spec states that burst should not cross the
 * 1K Boundaries. Receive buffer manager write operations are burst of 2 words => 3 lsb bits
 * of the address shall be set to 0.
 */
    COMPILER_ALIGNED( 8 )
    static uint8_t gs_uc_tx_buffer[ GMAC_TX_BUFFERS * GMAC_TX_UNITSIZE ];
#endif /* ipconfigZERO_COPY_TX_DRIVER */

/** Receive Buffer */
COMPILER_ALIGNED( 8 )
static uint8_t gs_uc_rx_buffer[ GMAC_RX_BUFFERS * GMAC_RX_UNITSIZE ];

/**
 * GMAC device memory management struct.
 */
typedef struct gmac_dev_mem
{
    /* Pointer to allocated buffer for RX. The address should be 8-byte aligned
     * and the size should be GMAC_RX_UNITSIZE * wRxSize. */
    uint8_t * p_rx_buffer;
    /* Pointer to allocated RX descriptor list. */
    gmac_rx_descriptor_t * p_rx_dscr;
    /* RX size, in number of registered units (RX descriptors). */
    /* Increased size from 16- to 32-bits, because it's more efficient */
    uint32_t us_rx_size;

    /* Pointer to allocated buffer for TX. The address should be 8-byte aligned
     * and the size should be GMAC_TX_UNITSIZE * wTxSize. */
    uint8_t * p_tx_buffer;
    /* Pointer to allocated TX descriptor list. */
    gmac_tx_descriptor_t * p_tx_dscr;
    /* TX size, in number of registered units (TX descriptors). */
    uint32_t us_tx_size;
} gmac_dev_mem_t;

/** Return count in buffer */
#define CIRC_CNT( head, tail, size )      ( ( ( head ) - ( tail ) ) % ( size ) )

/*
 * Return space available, from 0 to size-1.
 * Always leave one free char as a completely full buffer that has (head == tail),
 * which is the same as empty.
 */
#define CIRC_SPACE( head, tail, size )    CIRC_CNT( ( tail ), ( ( head ) + 1 ), ( size ) )

/** Circular buffer is empty ? */
#define CIRC_EMPTY( head, tail )          ( head == tail )
/** Clear circular buffer */
#define CIRC_CLEAR( head, tail )          do { ( head ) = 0; ( tail ) = 0; } while( ipFALSE_BOOL )

/** Increment head or tail */
static __inline void circ_inc32( int32_t * lHeadOrTail,
                                 uint32_t ulSize )
{
    ( *lHeadOrTail )++;

    if( ( *lHeadOrTail ) >= ( int32_t ) ulSize )
    {
        ( *lHeadOrTail ) = 0;
    }
}

/**
 * \brief Wait PHY operation to be completed.
 *
 * \param p_gmac HW controller address.
 * \param ul_retry The retry times, 0 to wait forever until completeness.
 *
 * Return GMAC_OK if the operation is completed successfully.
 */
static uint8_t gmac_wait_phy( Gmac * p_gmac,
                              const uint32_t ul_retry )
{
    volatile uint32_t ul_retry_count = 0;
    const uint32_t xPHYPollDelay = pdMS_TO_TICKS( 1ul );

    while( !gmac_is_phy_idle( p_gmac ) )
    {
        if( ul_retry == 0 )
        {
            continue;
        }

        ul_retry_count++;

        if( ul_retry_count >= ul_retry )
        {
            return GMAC_TIMEOUT;
        }

        /* Block the task to allow other tasks to execute while the PHY
         * is not connected. */
        vTaskDelay( xPHYPollDelay );
    }

    return GMAC_OK;
}

/**
 * \brief Disable transfer, reset registers and descriptor lists.
 *
 * \param p_dev Pointer to GMAC driver instance.
 *
 */
static void gmac_reset_tx_mem( gmac_device_t * p_dev )
{
    Gmac * p_hw = p_dev->p_hw;
    uint8_t * p_tx_buff = p_dev->p_tx_buffer;
    gmac_tx_descriptor_t * p_td = p_dev->p_tx_dscr;

    uint32_t ul_index;
    uint32_t ul_address;

    /* Disable TX */
    gmac_enable_transmit( p_hw, 0 );

    /* Set up the TX descriptors */
    CIRC_CLEAR( p_dev->l_tx_head, p_dev->l_tx_tail );

    for( ul_index = 0; ul_index < p_dev->ul_tx_list_size; ul_index++ )
    {
        #if ( ipconfigZERO_COPY_TX_DRIVER != 0 )
            {
                ul_address = ( uint32_t ) 0u;
            }
        #else
            {
                ul_address = ( uint32_t ) ( &( p_tx_buff[ ul_index * GMAC_TX_UNITSIZE ] ) );
            }
        #endif /* ipconfigZERO_COPY_TX_DRIVER */
        p_td[ ul_index ].addr = ul_address;
        p_td[ ul_index ].status.val = GMAC_TXD_USED;
    }

    p_td[ p_dev->ul_tx_list_size - 1 ].status.val =
        GMAC_TXD_USED | GMAC_TXD_WRAP;

    /* Set transmit buffer queue */
    gmac_set_tx_queue( p_hw, ( uint32_t ) p_td );
}

/**
 * \brief Disable receiver, reset registers and descriptor list.
 *
 * \param p_drv Pointer to GMAC Driver instance.
 */
static void gmac_reset_rx_mem( gmac_device_t * p_dev )
{
    Gmac * p_hw = p_dev->p_hw;
    uint8_t * p_rx_buff = p_dev->p_rx_buffer;
    gmac_rx_descriptor_t * pRd = p_dev->p_rx_dscr;

    uint32_t ul_index;
    uint32_t ul_address;

    /* Disable RX */
    gmac_enable_receive( p_hw, 0 );

    /* Set up the RX descriptors */
    p_dev->ul_rx_idx = 0;

    for( ul_index = 0; ul_index < p_dev->ul_rx_list_size; ul_index++ )
    {
        ul_address = ( uint32_t ) ( &( p_rx_buff[ ul_index * GMAC_RX_UNITSIZE ] ) );
        pRd[ ul_index ].addr.val = ul_address & GMAC_RXD_ADDR_MASK;
        pRd[ ul_index ].status.val = 0;
    }

    pRd[ p_dev->ul_rx_list_size - 1 ].addr.val |= GMAC_RXD_WRAP;

    /* Set receive buffer queue */
    gmac_set_rx_queue( p_hw, ( uint32_t ) pRd );
}


/**
 * \brief Initialize the allocated buffer lists for GMAC driver to transfer data.
 * Must be invoked after gmac_dev_init() but before RX/TX starts.
 *
 * \note If input address is not 8-byte aligned, the address is automatically
 *       adjusted and the list size is reduced by one.
 *
 * \param p_gmac Pointer to GMAC instance.
 * \param p_gmac_dev Pointer to GMAC device instance.
 * \param p_dev_mm Pointer to the GMAC memory management control block.
 * \param p_tx_cb Pointer to allocated TX callback list.
 *
 * \return GMAC_OK or GMAC_PARAM.
 */
static uint8_t gmac_init_mem( Gmac * p_gmac,
                              gmac_device_t * p_gmac_dev,
                              gmac_dev_mem_t * p_dev_mm
#if ( GMAC_USES_TX_CALLBACK != 0 )
                                  ,
                                  gmac_dev_tx_cb_t * p_tx_cb
#endif
                              )
{
    if( ( p_dev_mm->us_rx_size <= 1 ) || p_dev_mm->us_tx_size <= 1
        #if ( GMAC_USES_TX_CALLBACK != 0 )
            || p_tx_cb == NULL
        #endif
        )
    {
        return GMAC_PARAM;
    }

    /* Assign RX buffers */
    if( ( ( uint32_t ) p_dev_mm->p_rx_buffer & 0x7 ) ||
        ( ( uint32_t ) p_dev_mm->p_rx_dscr & 0x7 ) )
    {
        p_dev_mm->us_rx_size--;
    }

    p_gmac_dev->p_rx_buffer =
        ( uint8_t * ) ( ( uint32_t ) p_dev_mm->p_rx_buffer & 0xFFFFFFF8 );
    p_gmac_dev->p_rx_dscr =
        ( gmac_rx_descriptor_t * ) ( ( uint32_t ) p_dev_mm->p_rx_dscr
                                     & 0xFFFFFFF8 );
    p_gmac_dev->ul_rx_list_size = p_dev_mm->us_rx_size;

    /* Assign TX buffers */
    if( ( ( uint32_t ) p_dev_mm->p_tx_buffer & 0x7 ) ||
        ( ( uint32_t ) p_dev_mm->p_tx_dscr & 0x7 ) )
    {
        p_dev_mm->us_tx_size--;
    }

    p_gmac_dev->p_tx_buffer =
        ( uint8_t * ) ( ( uint32_t ) p_dev_mm->p_tx_buffer & 0xFFFFFFF8 );
    p_gmac_dev->p_tx_dscr =
        ( gmac_tx_descriptor_t * ) ( ( uint32_t ) p_dev_mm->p_tx_dscr
                                     & 0xFFFFFFF8 );
    p_gmac_dev->ul_tx_list_size = p_dev_mm->us_tx_size;
    #if ( GMAC_USES_TX_CALLBACK != 0 )
        p_gmac_dev->func_tx_cb_list = p_tx_cb;
    #endif
    /* Reset TX & RX */
    gmac_reset_rx_mem( p_gmac_dev );
    gmac_reset_tx_mem( p_gmac_dev );

    /* Enable Rx and Tx, plus the statistics register */
    gmac_enable_transmit( p_gmac, true );
    gmac_enable_receive( p_gmac, true );
    gmac_enable_statistics_write( p_gmac, true );

    /* Set up the interrupts for transmission and errors */
    gmac_enable_interrupt( p_gmac,
                           GMAC_IER_RXUBR | /* Enable receive used bit read interrupt. */
                           GMAC_IER_TUR |   /* Enable transmit underrun interrupt. */
                           GMAC_IER_RLEX |  /* Enable retry limit  exceeded interrupt. */
                           GMAC_IER_TFC |   /* Enable transmit buffers exhausted in mid-frame interrupt. */
                           GMAC_IER_TCOMP | /* Enable transmit complete interrupt. */
                           GMAC_IER_ROVR |  /* Enable receive overrun interrupt. */
                           GMAC_IER_HRESP | /* Enable Hresp not OK interrupt. */
                           GMAC_IER_PFNZ |  /* Enable pause frame received interrupt. */
                           GMAC_IER_PTZ );  /* Enable pause time zero interrupt. */

    return GMAC_OK;
}

/**
 * \brief Read the PHY register.
 *
 * \param p_gmac   Pointer to the GMAC instance.
 * \param uc_phy_address PHY address.
 * \param uc_address Register address.
 * \param p_value Pointer to a 32-bit location to store read data.
 *
 * \Return GMAC_OK if successfully, GMAC_TIMEOUT if timeout.
 */
uint8_t gmac_phy_read( Gmac * p_gmac,
                       uint8_t uc_phy_address,
                       uint8_t uc_address,
                       uint32_t * p_value )
{
    gmac_maintain_phy( p_gmac, uc_phy_address, uc_address, 1, 0 );

    if( gmac_wait_phy( p_gmac, MAC_PHY_RETRY_MAX ) == GMAC_TIMEOUT )
    {
        return GMAC_TIMEOUT;
    }

    *p_value = gmac_get_phy_data( p_gmac );
    return GMAC_OK;
}

/**
 * \brief Write the PHY register.
 *
 * \param p_gmac   Pointer to the GMAC instance.
 * \param uc_phy_address PHY Address.
 * \param uc_address Register Address.
 * \param ul_value Data to write, actually 16-bit data.
 *
 * \Return GMAC_OK if successfully, GMAC_TIMEOUT if timeout.
 */
uint8_t gmac_phy_write( Gmac * p_gmac,
                        uint8_t uc_phy_address,
                        uint8_t uc_address,
                        uint32_t ul_value )
{
    gmac_maintain_phy( p_gmac, uc_phy_address, uc_address, 0, ul_value );

    if( gmac_wait_phy( p_gmac, MAC_PHY_RETRY_MAX ) == GMAC_TIMEOUT )
    {
        return GMAC_TIMEOUT;
    }

    return GMAC_OK;
}

/**
 * \brief Initialize the GMAC driver.
 *
 * \param p_gmac   Pointer to the GMAC instance.
 * \param p_gmac_dev Pointer to the GMAC device instance.
 * \param p_opt GMAC configure options.
 */
void gmac_dev_init( Gmac * p_gmac,
                    gmac_device_t * p_gmac_dev,
                    gmac_options_t * p_opt )
{
    gmac_dev_mem_t gmac_dev_mm;

    /* Disable TX & RX and more */
    gmac_network_control( p_gmac, 0 );
    gmac_disable_interrupt( p_gmac, ~0u );


    gmac_clear_statistics( p_gmac );

    /* Clear all status bits in the receive status register. */
    gmac_clear_rx_status( p_gmac, GMAC_RSR_RXOVR | GMAC_RSR_REC | GMAC_RSR_BNA );

    /* Clear all status bits in the transmit status register */
    gmac_clear_tx_status( p_gmac, GMAC_TSR_UBR | GMAC_TSR_COL | GMAC_TSR_RLE
                          | GMAC_TSR_TFC | GMAC_TSR_TXCOMP | GMAC_TSR_UND );

    /* Clear interrupts */
    gmac_get_interrupt_status( p_gmac );
    #if !defined( ETHERNET_CONF_DATA_OFFSET )

        /*  Receive Buffer Offset
         * Indicates the number of bytes by which the received data
         * is offset from the start of the receive buffer
         * which can be handy for alignment reasons */
        /* Note: FreeRTOS+TCP wants to have this offset set to 2 bytes */
    #error ETHERNET_CONF_DATA_OFFSET not defined, assuming 0
    #endif

    /* Enable the copy of data into the buffers
     * ignore broadcasts, and not copy FCS. */

    gmac_set_configure( p_gmac,
                        ( gmac_get_configure( p_gmac ) & ~GMAC_NCFGR_RXBUFO_Msk ) |
                        GMAC_NCFGR_RFCS | /*  Remove FCS, frame check sequence (last 4 bytes) */
                        GMAC_NCFGR_PEN |  /* Pause Enable */
                        GMAC_NCFGR_RXBUFO( ETHERNET_CONF_DATA_OFFSET ) |
                        GMAC_RXD_RXCOEN );

    /*
     * GMAC_DCFGR_TXCOEN: (GMAC_DCFGR) Transmitter Checksum Generation Offload Enable.
     * Note: that SAM4E does have RX checksum offloading
     * but TX checksum offloading has NOT been implemented.
     */

    gmac_set_dma( p_gmac,
                  gmac_get_dma( p_gmac ) | GMAC_DCFGR_TXCOEN );

    gmac_enable_copy_all( p_gmac, p_opt->uc_copy_all_frame );
    gmac_disable_broadcast( p_gmac, p_opt->uc_no_boardcast );

    /* Fill in GMAC device memory management */
    gmac_dev_mm.p_rx_buffer = gs_uc_rx_buffer;
    gmac_dev_mm.p_rx_dscr = gs_rx_desc;
    gmac_dev_mm.us_rx_size = GMAC_RX_BUFFERS;

    #if ( ipconfigZERO_COPY_TX_DRIVER != 0 )
        {
            gmac_dev_mm.p_tx_buffer = NULL;
        }
    #else
        {
            gmac_dev_mm.p_tx_buffer = gs_uc_tx_buffer;
        }
    #endif
    gmac_dev_mm.p_tx_dscr = gs_tx_desc;
    gmac_dev_mm.us_tx_size = GMAC_TX_BUFFERS;

    gmac_init_mem( p_gmac, p_gmac_dev, &gmac_dev_mm
                   #if ( GMAC_USES_TX_CALLBACK != 0 )
                       , gs_tx_callback
                   #endif
                   );

    gmac_set_address( p_gmac, 0, p_opt->uc_mac_addr );
}

/**
 * \brief Frames can be read from the GMAC in multiple sections.
 *
 * Returns > 0 if a complete frame is available
 * It also it cleans up incomplete older frames
 */

static uint32_t gmac_dev_poll( gmac_device_t * p_gmac_dev )
{
    uint32_t ulReturn = 0;
    int32_t ulIndex = p_gmac_dev->ul_rx_idx;
    gmac_rx_descriptor_t * pxHead = &p_gmac_dev->p_rx_dscr[ ulIndex ];

    /* Discard any incomplete frames */
    while( ( pxHead->addr.val & GMAC_RXD_OWNERSHIP ) &&
           ( pxHead->status.val & GMAC_RXD_SOF ) == 0 )
    {
        pxHead->addr.val &= ~( GMAC_RXD_OWNERSHIP );
        circ_inc32( &ulIndex, p_gmac_dev->ul_rx_list_size );
        pxHead = &p_gmac_dev->p_rx_dscr[ ulIndex ];
        p_gmac_dev->ul_rx_idx = ulIndex;
        #if ( GMAC_STATS != 0 )
            {
                gmacStats.incompCount++;
            }
        #endif
    }

    while( ( pxHead->addr.val & GMAC_RXD_OWNERSHIP ) != 0 )
    {
        if( ( pxHead->status.val & GMAC_RXD_EOF ) != 0 )
        {
            /* Here a complete frame has been seen with SOF and EOF */
            ulReturn = pxHead->status.bm.len;
            break;
        }

        circ_inc32( &ulIndex, p_gmac_dev->ul_rx_list_size );
        pxHead = &p_gmac_dev->p_rx_dscr[ ulIndex ];

        if( ( pxHead->addr.val & GMAC_RXD_OWNERSHIP ) == 0 )
        {
            /* CPU is not the owner (yet) */
            break;
        }

        if( ( pxHead->status.val & GMAC_RXD_SOF ) != 0 )
        {
            /* Strange, we found a new Start Of Frame
             * discard previous segments */
            int32_t ulPrev = p_gmac_dev->ul_rx_idx;
            pxHead = &p_gmac_dev->p_rx_dscr[ ulPrev ];

            do
            {
                pxHead->addr.val &= ~( GMAC_RXD_OWNERSHIP );
                circ_inc32( &ulPrev, p_gmac_dev->ul_rx_list_size );
                pxHead = &p_gmac_dev->p_rx_dscr[ ulPrev ];
                #if ( GMAC_STATS != 0 )
                    {
                        gmacStats.truncCount++;
                    }
                #endif
            } while( ulPrev != ulIndex );

            p_gmac_dev->ul_rx_idx = ulIndex;
        }
    }

    return ulReturn;
}

/**
 * \brief Frames can be read from the GMAC in multiple sections.
 * Read ul_frame_size bytes from the GMAC receive buffers to pcTo.
 * p_rcv_size is the size of the entire frame.  Generally gmac_read
 * will be repeatedly called until the sum of all the ul_frame_size equals
 * the value of p_rcv_size.
 *
 * \param p_gmac_dev Pointer to the GMAC device instance.
 * \param p_frame Address of the frame buffer.
 * \param ul_frame_size  Length of the frame.
 * \param p_rcv_size   Received frame size.
 *
 * \return GMAC_OK if receiving frame successfully, otherwise failed.
 */
uint32_t gmac_dev_read( gmac_device_t * p_gmac_dev,
                        uint8_t * p_frame,
                        uint32_t ul_frame_size,
                        uint32_t * p_rcv_size )
{
    int32_t nextIdx; /* A copy of the Rx-index 'ul_rx_idx' */
    int32_t bytesLeft = gmac_dev_poll( p_gmac_dev );
    gmac_rx_descriptor_t * pxHead;

    if( bytesLeft == 0 )
    {
        return GMAC_RX_NULL;
    }

    /* gmac_dev_poll has confirmed that there is a complete frame at
     * the current position 'ul_rx_idx'
     */
    nextIdx = p_gmac_dev->ul_rx_idx;

    /* Read +2 bytes because buffers are aligned at -2 bytes */
    bytesLeft = min( bytesLeft + 2, ( int32_t ) ul_frame_size );

    /* The frame will be copied in 1 or 2 memcpy's */
    if( ( p_frame != NULL ) && ( bytesLeft != 0 ) )
    {
        const uint8_t * source;
        int32_t left;
        int32_t toCopy;

        source = p_gmac_dev->p_rx_buffer + nextIdx * GMAC_RX_UNITSIZE;
        left = bytesLeft;
        toCopy = ( p_gmac_dev->ul_rx_list_size - nextIdx ) * GMAC_RX_UNITSIZE;

        if( toCopy > left )
        {
            toCopy = left;
        }

        memcpy( p_frame, source, toCopy );
        left -= toCopy;

        if( left != 0ul )
        {
            memcpy( p_frame + toCopy, ( void * ) p_gmac_dev->p_rx_buffer, left );
        }
    }

    do
    {
        pxHead = &p_gmac_dev->p_rx_dscr[ nextIdx ];
        pxHead->addr.val &= ~( GMAC_RXD_OWNERSHIP );
        circ_inc32( &nextIdx, p_gmac_dev->ul_rx_list_size );
    } while( ( pxHead->status.val & GMAC_RXD_EOF ) == 0 );

    p_gmac_dev->ul_rx_idx = nextIdx;

    *p_rcv_size = bytesLeft;

    return GMAC_OK;
}


extern void vGMACGenerateChecksum( uint8_t * apBuffer );

/**
 * \brief Send ulLength bytes from pcFrom. This copies the buffer to one of the
 * GMAC Tx buffers, and then indicates to the GMAC that the buffer is ready.
 * If lEndOfFrame is true then the data being copied is the end of the frame
 * and the frame can be transmitted.
 *
 * \param p_gmac_dev Pointer to the GMAC device instance.
 * \param p_buffer       Pointer to the data buffer.
 * \param ul_size    Length of the frame.
 * \param func_tx_cb  Transmit callback function.
 *
 * \return Length sent.
 */
uint32_t gmac_dev_write( gmac_device_t * p_gmac_dev,
                         void * p_buffer,
                         uint32_t ul_size,
                         gmac_dev_tx_cb_t func_tx_cb )
{
    volatile gmac_tx_descriptor_t * p_tx_td;

    #if ( GMAC_USES_TX_CALLBACK != 0 )
        volatile gmac_dev_tx_cb_t * p_func_tx_cb;
    #endif

    Gmac * p_hw = p_gmac_dev->p_hw;

    #if ( GMAC_USES_TX_CALLBACK == 0 )
        ( void ) func_tx_cb;
    #endif

    /* Check parameter */
    if( ul_size > GMAC_TX_UNITSIZE )
    {
        return GMAC_PARAM;
    }

    /* Pointers to the current transmit descriptor */
    p_tx_td = &p_gmac_dev->p_tx_dscr[ p_gmac_dev->l_tx_head ];

    /* If no free TxTd, buffer can't be sent, schedule the wakeup callback */
/*	if (CIRC_SPACE(p_gmac_dev->l_tx_head, p_gmac_dev->l_tx_tail, */
/*					p_gmac_dev->ul_tx_list_size) == 0) */
    {
        if( ( p_tx_td->status.val & GMAC_TXD_USED ) == 0 )
        {
            return GMAC_TX_BUSY;
        }
    }
    #if ( GMAC_USES_TX_CALLBACK != 0 )
        /* Pointers to the current Tx callback */
        p_func_tx_cb = &p_gmac_dev->func_tx_cb_list[ p_gmac_dev->l_tx_head ];
    #endif

    /* Set up/copy data to transmission buffer */
    if( p_buffer && ul_size )
    {
        /* Driver manages the ring buffer */

        /* Calculating the checksum here is faster than calculating it from the GMAC buffer
         * because within p_buffer, it is well aligned */
        #if ( ipconfigZERO_COPY_TX_DRIVER != 0 )
            {
                /* Zero-copy... */
                p_tx_td->addr = ( uint32_t ) p_buffer;
            }
        #else
            {
                /* Or Memcopy... */
                memcpy( ( void * ) p_tx_td->addr, p_buffer, ul_size );
            }
        #endif /* ipconfigZERO_COPY_TX_DRIVER */
        vGMACGenerateChecksum( ( uint8_t * ) p_tx_td->addr );
    }

    #if ( GMAC_USES_TX_CALLBACK != 0 )
        /* Tx callback */
        *p_func_tx_cb = func_tx_cb;
    #endif

    /* Update transmit descriptor status */

    /* The buffer size defined is the length of ethernet frame,
     * so it's always the last buffer of the frame. */
    if( p_gmac_dev->l_tx_head == ( int32_t ) ( p_gmac_dev->ul_tx_list_size - 1 ) )
    {
        /* No need to 'and' with GMAC_TXD_LEN_MASK because ul_size has been checked */
        p_tx_td->status.val =
            ul_size | GMAC_TXD_LAST | GMAC_TXD_WRAP;
    }
    else
    {
        p_tx_td->status.val =
            ul_size | GMAC_TXD_LAST;
    }

    circ_inc32( &p_gmac_dev->l_tx_head, p_gmac_dev->ul_tx_list_size );

    /* Now start to transmit if it is still not done */
    gmac_start_transmission( p_hw );

    return GMAC_OK;
}

/**
 * \brief Get current load of transmit.
 *
 * \param p_gmac_dev Pointer to the GMAC device instance.
 *
 * \return Current load of transmit.
 */
#if ( GMAC_USES_TX_CALLBACK != 0 )
/* Without defining GMAC_USES_TX_CALLBACK, l_tx_tail won't be updated */
    uint32_t gmac_dev_get_tx_load( gmac_device_t * p_gmac_dev )
    {
        uint16_t us_head = p_gmac_dev->l_tx_head;
        uint16_t us_tail = p_gmac_dev->l_tx_tail;

        return CIRC_CNT( us_head, us_tail, p_gmac_dev->ul_tx_list_size );
    }
#endif

/**
 * \brief Register/Clear RX callback. Callback will be invoked after the next received
 * frame.
 *
 * When gmac_dev_read() returns GMAC_RX_NULL, the application task calls
 * gmac_dev_set_rx_callback() to register func_rx_cb() callback and enters suspend state.
 * The callback is in charge to resume the task once a new frame has been
 * received. The next time gmac_dev_read() is called, it will be successful.
 *
 * This function is usually invoked from the RX callback itself with NULL
 * callback, to unregister. Once the callback has resumed the application task,
 * there is no need to invoke the callback again.
 *
 * \param p_gmac_dev Pointer to the GMAC device instance.
 * \param func_tx_cb  Receive callback function.
 */
void gmac_dev_set_rx_callback( gmac_device_t * p_gmac_dev,
                               gmac_dev_rx_cb_t func_rx_cb )
{
    Gmac * p_hw = p_gmac_dev->p_hw;

    if( func_rx_cb == NULL )
    {
        gmac_disable_interrupt( p_hw, GMAC_IDR_RCOMP );
        p_gmac_dev->func_rx_cb = NULL;
    }
    else
    {
        p_gmac_dev->func_rx_cb = func_rx_cb;
        gmac_enable_interrupt( p_hw, GMAC_IER_RCOMP );
    }
}

/**
 *  \brief Register/Clear TX wakeup callback.
 *
 * When gmac_dev_write() returns GMAC_TX_BUSY (all transmit descriptor busy), the application
 * task calls gmac_dev_set_tx_wakeup_callback() to register func_wakeup() callback and
 * enters suspend state. The callback is in charge to resume the task once
 * several transmit descriptors have been released. The next time gmac_dev_write() will be called,
 * it shall be successful.
 *
 * This function is usually invoked with NULL callback from the TX wakeup
 * callback itself, to unregister. Once the callback has resumed the
 * application task, there is no need to invoke the callback again.
 *
 * \param p_gmac_dev   Pointer to GMAC device instance.
 * \param func_wakeup    Pointer to wakeup callback function.
 * \param uc_threshold Number of free transmit descriptor before wakeup callback invoked.
 *
 * \return GMAC_OK, GMAC_PARAM on parameter error.
 */
#if ( GMAC_USES_WAKEUP_CALLBACK )
    uint8_t gmac_dev_set_tx_wakeup_callback( gmac_device_t * p_gmac_dev,
                                             gmac_dev_wakeup_cb_t func_wakeup_cb,
                                             uint8_t uc_threshold )
    {
        if( func_wakeup_cb == NULL )
        {
            p_gmac_dev->func_wakeup_cb = NULL;
        }
        else
        {
            if( uc_threshold <= p_gmac_dev->ul_tx_list_size )
            {
                p_gmac_dev->func_wakeup_cb = func_wakeup_cb;
                p_gmac_dev->uc_wakeup_threshold = uc_threshold;
            }
            else
            {
                return GMAC_PARAM;
            }
        }

        return GMAC_OK;
    }
#endif /* GMAC_USES_WAKEUP_CALLBACK */

/**
 * \brief Reset TX & RX queue & statistics.
 *
 * \param p_gmac_dev   Pointer to GMAC device instance.
 */
void gmac_dev_reset( gmac_device_t * p_gmac_dev )
{
    Gmac * p_hw = p_gmac_dev->p_hw;

    gmac_reset_rx_mem( p_gmac_dev );
    gmac_reset_tx_mem( p_gmac_dev );
    gmac_network_control( p_hw, GMAC_NCR_TXEN | GMAC_NCR_RXEN
                          | GMAC_NCR_WESTAT | GMAC_NCR_CLRSTAT );
}

void gmac_dev_halt( Gmac * p_gmac );

void gmac_dev_halt( Gmac * p_gmac )
{
    gmac_network_control( p_gmac, GMAC_NCR_WESTAT | GMAC_NCR_CLRSTAT );
    gmac_disable_interrupt( p_gmac, ~0u );
}


/**
 * \brief GMAC Interrupt handler.
 *
 * \param p_gmac_dev   Pointer to GMAC device instance.
 */

#if ( GMAC_STATS != 0 )
    extern int logPrintf( const char * pcFormat,
                          ... );

    void gmac_show_irq_counts()
    {
        int index;

        for( index = 0; index < ARRAY_SIZE( intPairs ); index++ )
        {
            if( gmacStats.intStatus[ intPairs[ index ].index ] )
            {
                logPrintf( "%s : %6u\n", intPairs[ index ].name, gmacStats.intStatus[ intPairs[ index ].index ] );
            }
        }
    }
#endif /* if ( GMAC_STATS != 0 ) */

void gmac_handler( gmac_device_t * p_gmac_dev )
{
    Gmac * p_hw = p_gmac_dev->p_hw;

    #if ( GMAC_USES_TX_CALLBACK != 0 )
        gmac_tx_descriptor_t * p_tx_td;
        gmac_dev_tx_cb_t * p_tx_cb = NULL;
        uint32_t ul_tx_status_flag;
    #endif
    #if ( GMAC_STATS != 0 )
        int index;
    #endif

    /* volatile */ uint32_t ul_isr;
    /* volatile */ uint32_t ul_rsr;
    /* volatile */ uint32_t ul_tsr;

    ul_isr = gmac_get_interrupt_status( p_hw );
    ul_rsr = gmac_get_rx_status( p_hw );
    ul_tsr = gmac_get_tx_status( p_hw );

/*	Why clear bits that are ignored anyway ? */
/*	ul_isr &= ~(gmac_get_interrupt_mask(p_hw) | 0xF8030300); */
    #if ( GMAC_STATS != 0 )
        {
            for( index = 0; index < ARRAY_SIZE( intPairs ); index++ )
            {
                if( ul_isr & intPairs[ index ].mask )
                {
                    gmacStats.intStatus[ intPairs[ index ].index ]++;
                }
            }
        }
    #endif /* GMAC_STATS != 0 */

    /* RX packet */
    if( ( ul_isr & GMAC_ISR_RCOMP ) || ( ul_rsr & ( GMAC_RSR_REC | GMAC_RSR_RXOVR | GMAC_RSR_BNA ) ) )
    {
        /* Clear status */
        gmac_clear_rx_status( p_hw, ul_rsr );

        if( ul_isr & GMAC_ISR_RCOMP )
        {
            ul_rsr |= GMAC_RSR_REC;
        }

        /* Invoke callbacks which can be useful to wake up a task */
        if( p_gmac_dev->func_rx_cb )
        {
            p_gmac_dev->func_rx_cb( ul_rsr );
        }
    }

    /* TX packet */
    if( ( ul_isr & GMAC_ISR_TCOMP ) || ( ul_tsr & ( GMAC_TSR_TXCOMP | GMAC_TSR_COL | GMAC_TSR_RLE | GMAC_TSR_UND ) ) )
    {
        #if ( GMAC_USES_TX_CALLBACK != 0 )
            ul_tx_status_flag = GMAC_TSR_TXCOMP;
        #endif
        /* A frame transmitted */

        /* Check RLE */
        if( ul_tsr & GMAC_TSR_RLE )
        {
            /* Status RLE & Number of discarded buffers */
            #if ( GMAC_USES_TX_CALLBACK != 0 )
                ul_tx_status_flag = GMAC_TSR_RLE | CIRC_CNT( p_gmac_dev->l_tx_head,
                                                             p_gmac_dev->l_tx_tail, p_gmac_dev->ul_tx_list_size );
                p_tx_cb = &p_gmac_dev->func_tx_cb_list[ p_gmac_dev->l_tx_tail ];
            #endif
            gmac_reset_tx_mem( p_gmac_dev );
            gmac_enable_transmit( p_hw, 1 );
        }

        /* Clear status */
        gmac_clear_tx_status( p_hw, ul_tsr );

        #if ( GMAC_USES_TX_CALLBACK != 0 )
            if( !CIRC_EMPTY( p_gmac_dev->l_tx_head, p_gmac_dev->l_tx_tail ) )
            {
                /* Check the buffers */
                do
                {
                    p_tx_td = &p_gmac_dev->p_tx_dscr[ p_gmac_dev->l_tx_tail ];
                    p_tx_cb = &p_gmac_dev->func_tx_cb_list[ p_gmac_dev->l_tx_tail ];

                    /* Any error? Exit if buffer has not been sent yet */
                    if( ( p_tx_td->status.val & GMAC_TXD_USED ) == 0 )
                    {
                        break;
                    }

                    /* Notify upper layer that a packet has been sent */
                    if( *p_tx_cb )
                    {
                        ( *p_tx_cb )( ul_tx_status_flag, ( void * ) p_tx_td->addr );
                        #if ( ipconfigZERO_COPY_TX_DRIVER != 0 )
                            {
                                p_tx_td->addr = 0ul;
                            }
                        #endif /* ipconfigZERO_COPY_TX_DRIVER */
                    }

                    circ_inc32( &p_gmac_dev->l_tx_tail, p_gmac_dev->ul_tx_list_size );
                } while( CIRC_CNT( p_gmac_dev->l_tx_head, p_gmac_dev->l_tx_tail,
                                   p_gmac_dev->ul_tx_list_size ) );
            }

            if( ul_tsr & GMAC_TSR_RLE )
            {
                /* Notify upper layer RLE */
                if( *p_tx_cb )
                {
                    ( *p_tx_cb )( ul_tx_status_flag, NULL );
                }
            }
        #endif /* GMAC_USES_TX_CALLBACK */

        #if ( GMAC_USES_WAKEUP_CALLBACK )

            /* If a wakeup has been scheduled, notify upper layer that it can
             * send other packets, and the sending will be successful. */
            if( ( CIRC_SPACE( p_gmac_dev->l_tx_head, p_gmac_dev->l_tx_tail,
                              p_gmac_dev->ul_tx_list_size ) >= p_gmac_dev->uc_wakeup_threshold ) &&
                p_gmac_dev->func_wakeup_cb )
            {
                p_gmac_dev->func_wakeup_cb();
            }
        #endif
    }
}

/*@} */

/*/ @cond 0 */
/**INDENT-OFF**/
#ifdef __cplusplus
}
#endif
/**INDENT-ON**/
/*/ @endcond */