/**
* @file
* Ethernet Interface Skeleton
*
*/

/*
* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
* All rights reserved.
*
* 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 the author may not be used to endorse or promote products
*    derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
* SHALL THE AUTHOR 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.
*
* This file is part of the lwIP TCP/IP stack.
*
* Author: Adam Dunkels <adam@sics.se>
*
*/

/*
* This file is a skeleton for developing Ethernet network interface
* drivers for lwIP. Add code to the low_level functions and do a
* search-and-replace for the word "ethernetif" to replace it with
* something that better describes your network interface.
*/

#include "lwip/opt.h"
#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/pbuf.h"
#include "lwip/timers.h"
#include "netif/etharp.h"
#include "err.h"
#include "ethernetif.h"

#include "eth_opts.h"
#include "stm32f4x7_eth.h"
#include <string.h>


#define netifMTU                                (1500)
#define netifINTERFACE_TASK_STACK_SIZE		( 400 )
#define netifINTERFACE_TASK_PRIORITY		( configMAX_PRIORITIES - 1 )
#define netifGUARD_BLOCK_TIME			( 250 )
/* The time to block waiting for input. */
#define emacBLOCK_TIME_WAITING_FOR_INPUT	( ( portTickType ) 100 )

/* Define those to better describe your network interface. */
#define IFNAME0 's'
#define IFNAME1 't'


static struct netif *s_pxNetIf = NULL;
xSemaphoreHandle s_xSemaphore = NULL;


/* Ethernet Rx & Tx DMA Descriptors */
extern ETH_DMADESCTypeDef  DMARxDscrTab[ETH_RXBUFNB], DMATxDscrTab[ETH_TXBUFNB];

/* Ethernet Receive buffers  */
extern uint8_t Rx_Buff[ETH_RXBUFNB][ETH_RX_BUF_SIZE]; 

/* Ethernet Transmit buffers */
extern uint8_t Tx_Buff[ETH_TXBUFNB][ETH_TX_BUF_SIZE]; 

/* Global pointers to track current transmit and receive descriptors */
extern ETH_DMADESCTypeDef  *DMATxDescToSet;
extern ETH_DMADESCTypeDef  *DMARxDescToGet;

/* Global pointer for last received frame infos */
extern ETH_DMA_Rx_Frame_infos *DMA_RX_FRAME_infos;


static void ethernetif_input( void * pvParameters );
static void arp_timer(void *arg);


/**
* In this function, the hardware should be initialized.
* Called from ethernetif_init().
*
* @param netif the already initialized lwip network interface structure
*        for this ethernetif
*/
static void low_level_init(struct netif *netif)
{
  uint32_t i;

  /* set netif MAC hardware address length */
  netif->hwaddr_len = ETHARP_HWADDR_LEN;

  /* set netif MAC hardware address */
  netif->hwaddr[0] =  MAC_ADDR0;
  netif->hwaddr[1] =  MAC_ADDR1;
  netif->hwaddr[2] =  MAC_ADDR2;
  netif->hwaddr[3] =  MAC_ADDR3;
  netif->hwaddr[4] =  MAC_ADDR4;
  netif->hwaddr[5] =  MAC_ADDR5;

  /* set netif maximum transfer unit */
  netif->mtu = 1500;

  /* Accept broadcast address and ARP traffic */
  netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP;

  s_pxNetIf =netif;

  /* create binary semaphore used for informing ethernetif of frame reception */
  if (s_xSemaphore == NULL)
  {
    vSemaphoreCreateBinary(s_xSemaphore);
    xSemaphoreTake( s_xSemaphore, 0);
  }

  /* initialize MAC address in ethernet MAC */ 
  ETH_MACAddressConfig(ETH_MAC_Address0, netif->hwaddr); 

  /* Initialize Tx Descriptors list: Chain Mode */
  ETH_DMATxDescChainInit(DMATxDscrTab, &Tx_Buff[0][0], ETH_TXBUFNB);
  /* Initialize Rx Descriptors list: Chain Mode  */
  ETH_DMARxDescChainInit(DMARxDscrTab, &Rx_Buff[0][0], ETH_RXBUFNB);

  /* Enable Ethernet Rx interrrupt */
  { 
    for(i=0; i<ETH_RXBUFNB; i++)
    {
      ETH_DMARxDescReceiveITConfig(&DMARxDscrTab[i], ENABLE);
    }
  }

#ifdef CHECKSUM_BY_HARDWARE
  /* Enable the checksum insertion for the Tx frames */
  {
    for(i=0; i<ETH_TXBUFNB; i++)
    {
      ETH_DMATxDescChecksumInsertionConfig(&DMATxDscrTab[i], ETH_DMATxDesc_ChecksumTCPUDPICMPFull);
    }
  } 
#endif

  /* create the task that handles the ETH_MAC */
  xTaskCreate(ethernetif_input, (signed char*) "Eth_if", netifINTERFACE_TASK_STACK_SIZE, NULL,
              netifINTERFACE_TASK_PRIORITY,NULL);

    /* Enable MAC and DMA transmission and reception */
    ETH_Start();   
}


/**
* This function should do the actual transmission of the packet. The packet is
* contained in the pbuf that is passed to the function. This pbuf
* might be chained.
*
* @param netif the lwip network interface structure for this ethernetif
* @param p the MAC packet to send (e.g. IP packet including MAC addresses and type)
* @return ERR_OK if the packet could be sent
*         an err_t value if the packet couldn't be sent
*
* @note Returning ERR_MEM here if a DMA queue of your MAC is full can lead to
*       strange results. You might consider waiting for space in the DMA queue
*       to become availale since the stack doesn't retry to send a packet
*       dropped because of memory failure (except for the TCP timers).
*/

static err_t low_level_output(struct netif *netif, struct pbuf *p)
{
  static xSemaphoreHandle xTxSemaphore = NULL;
  struct pbuf *q;
  u8 *buffer ;
  __IO ETH_DMADESCTypeDef *DmaTxDesc;
  uint16_t framelength = 0;
  uint32_t bufferoffset = 0;
  uint32_t byteslefttocopy = 0;
  uint32_t payloadoffset = 0;

  if (xTxSemaphore == NULL)
  {
    vSemaphoreCreateBinary (xTxSemaphore);
  }

  if (xSemaphoreTake(xTxSemaphore, netifGUARD_BLOCK_TIME))
  {
    DmaTxDesc = DMATxDescToSet;
    buffer = (u8 *)(DmaTxDesc->Buffer1Addr);
    bufferoffset = 0;

    for(q = p; q != NULL; q = q->next) 
    {
      if((DmaTxDesc->Status & ETH_DMATxDesc_OWN) != (u32)RESET)
      {
        goto error;
      }

      /* Get bytes in current lwIP buffer  */
      byteslefttocopy = q->len;
      payloadoffset = 0;

      /* Check if the length of data to copy is bigger than Tx buffer size*/
      while( (byteslefttocopy + bufferoffset) > ETH_TX_BUF_SIZE )
      {
        /* Copy data to Tx buffer*/
        memcpy( (u8_t*)((u8_t*)buffer + bufferoffset), (u8_t*)((u8_t*)q->payload + payloadoffset), (ETH_TX_BUF_SIZE - bufferoffset) );

        /* Point to next descriptor */
        DmaTxDesc = (ETH_DMADESCTypeDef *)(DmaTxDesc->Buffer2NextDescAddr);

        /* Check if the buffer is available */
        if((DmaTxDesc->Status & ETH_DMATxDesc_OWN) != (u32)RESET)
        {
          goto error;
        }

        buffer = (u8 *)(DmaTxDesc->Buffer1Addr);

        byteslefttocopy = byteslefttocopy - (ETH_TX_BUF_SIZE - bufferoffset);
        payloadoffset = payloadoffset + (ETH_TX_BUF_SIZE - bufferoffset);
        framelength = framelength + (ETH_TX_BUF_SIZE - bufferoffset);
        bufferoffset = 0;
      }

      /* Copy the remaining bytes */
      memcpy( (u8_t*)((u8_t*)buffer + bufferoffset), (u8_t*)((u8_t*)q->payload + payloadoffset), byteslefttocopy );
      bufferoffset = bufferoffset + byteslefttocopy;
      framelength = framelength + byteslefttocopy;
    }

    /* Prepare transmit descriptors to give to DMA*/
    ETH_Prepare_Transmit_Descriptors(framelength);

    /* Give semaphore and exit */
  error:

    xSemaphoreGive(xTxSemaphore);
  }

  return ERR_OK;
}

/**
* Should allocate a pbuf and transfer the bytes of the incoming
* packet from the interface into the pbuf.
*
* @param netif the lwip network interface structure for this ethernetif
* @return a pbuf filled with the received packet (including MAC header)
*         NULL on memory error
*/
static struct pbuf * low_level_input(struct netif *netif)
{
  struct pbuf *p= NULL, *q;
  u32_t len;
  FrameTypeDef frame;
  u8 *buffer;
  __IO ETH_DMADESCTypeDef *DMARxDesc;
  uint32_t bufferoffset = 0;
  uint32_t payloadoffset = 0;
  uint32_t byteslefttocopy = 0;
  uint32_t i=0;  

  /* get received frame */
  frame = ETH_Get_Received_Frame_interrupt();

  /* Obtain the size of the packet and put it into the "len" variable. */
  len = frame.length;
  buffer = (u8 *)frame.buffer;
  
  if (len > 0)
  {
    /* We allocate a pbuf chain of pbufs from the Lwip buffer pool */
    p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
  }
  
  if (p != NULL)
  {
    DMARxDesc = frame.descriptor;
    bufferoffset = 0;
    for(q = p; q != NULL; q = q->next)
    {
      byteslefttocopy = q->len;
      payloadoffset = 0;

      /* Check if the length of bytes to copy in current pbuf is bigger than Rx buffer size*/
      while( (byteslefttocopy + bufferoffset) > ETH_RX_BUF_SIZE )
      {
        /* Copy data to pbuf*/
        memcpy( (u8_t*)((u8_t*)q->payload + payloadoffset), (u8_t*)((u8_t*)buffer + bufferoffset), (ETH_RX_BUF_SIZE - bufferoffset));

        /* Point to next descriptor */
        DMARxDesc = (ETH_DMADESCTypeDef *)(DMARxDesc->Buffer2NextDescAddr);
        buffer = (unsigned char *)(DMARxDesc->Buffer1Addr);

        byteslefttocopy = byteslefttocopy - (ETH_RX_BUF_SIZE - bufferoffset);
        payloadoffset = payloadoffset + (ETH_RX_BUF_SIZE - bufferoffset);
        bufferoffset = 0;
      }

      /* Copy remaining data in pbuf */
      memcpy( (u8_t*)((u8_t*)q->payload + payloadoffset), (u8_t*)((u8_t*)buffer + bufferoffset), byteslefttocopy);
      bufferoffset = bufferoffset + byteslefttocopy;
    }
  
  /* Release descriptors to DMA */
  DMARxDesc =frame.descriptor;

  /* Set Own bit in Rx descriptors: gives the buffers back to DMA */
  for (i=0; i<DMA_RX_FRAME_infos->Seg_Count; i++)
  {  
    DMARxDesc->Status = ETH_DMARxDesc_OWN;
    DMARxDesc = (ETH_DMADESCTypeDef *)(DMARxDesc->Buffer2NextDescAddr);
  }
  
  /* Clear Segment_Count */
  DMA_RX_FRAME_infos->Seg_Count =0;
  /* added for test*/
  }
  
  /* When Rx Buffer unavailable flag is set: clear it and resume reception */
  if ((ETH->DMASR & ETH_DMASR_RBUS) != (u32)RESET)  
  {
    /* Clear RBUS ETHERNET DMA flag */
    ETH->DMASR = ETH_DMASR_RBUS;
    /* Resume DMA reception */
    ETH->DMARPDR = 0;
  }
  return p;
}


/**
* This function is the ethernetif_input task, it is processed when a packet 
* is ready to be read from the interface. It uses the function low_level_input() 
* that should handle the actual reception of bytes from the network
* interface. Then the type of the received packet is determined and
* the appropriate input function is called.
*
* @param netif the lwip network interface structure for this ethernetif
*/
void ethernetif_input( void * pvParameters )
{
  struct pbuf *p;
  
  for( ;; )
  {
    if (xSemaphoreTake( s_xSemaphore, emacBLOCK_TIME_WAITING_FOR_INPUT)==pdTRUE)
    {
TRY_GET_NEXT_FRAME:
      p = low_level_input( s_pxNetIf );
      if   (p != NULL)
      {
        if (ERR_OK != s_pxNetIf->input( p, s_pxNetIf))
        {
          pbuf_free(p);
        }
        else
        {
          goto TRY_GET_NEXT_FRAME;
        }
      }
    }
  }
}

/**
* Should be called at the beginning of the program to set up the
* network interface. It calls the function low_level_init() to do the
* actual setup of the hardware.
*
* This function should be passed as a parameter to netif_add().
*
* @param netif the lwip network interface structure for this ethernetif
* @return ERR_OK if the loopif is initialized
*         ERR_MEM if private data couldn't be allocated
*         any other err_t on error
*/
err_t ethernetif_init(struct netif *netif)
{
  LWIP_ASSERT("netif != NULL", (netif != NULL));

#if LWIP_NETIF_HOSTNAME
  /* Initialize interface hostname */
  netif->hostname = "lwip";
#endif /* LWIP_NETIF_HOSTNAME */

  netif->name[0] = IFNAME0;
  netif->name[1] = IFNAME1;

  netif->output = etharp_output;
  netif->linkoutput = low_level_output;

  /* initialize the hardware */
  low_level_init(netif);

  etharp_init();
  sys_timeout(ARP_TMR_INTERVAL, arp_timer, NULL);

  return ERR_OK;
}


static void arp_timer(void *arg)
{
  etharp_tmr();
  sys_timeout(ARP_TMR_INTERVAL, arp_timer, NULL);
}

