/**
 * @file - stellarisif.c
 * lwIP Ethernet interface for Stellaris Devices
 *
 */

/**
 * 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>
 *
 */

/**
 * Copyright (c) 2008 Luminary Micro, Inc.
 *
 * This file is dervied from the ``ethernetif.c'' skeleton Ethernet network
 * interface driver for lwIP.
 *
 */

#include "lwip/opt.h"
#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/pbuf.h"
#include "lwip/sys.h"
#include <lwip/stats.h>
#include <lwip/snmp.h>
#include "netif/etharp.h"
#include "netif/ppp_oe.h"
#include "stellarisif.h"

/**
 * Sanity Check:  This interface driver will NOT work if the following defines
 * are incorrect.
 *
 */
#if (PBUF_LINK_HLEN != 16)
#error "PBUF_LINK_HLEN must be 16 for this interface driver!"
#endif
#if (ETH_PAD_SIZE != 2)
#error "ETH_PAD_SIZE must be 2 for this interface driver!"
#endif
#if (!SYS_LIGHTWEIGHT_PROT)
#error "SYS_LIGHTWEIGHT_PROT must be enabled for this interface driver!"
#endif

/**
 * Number of pbufs supported in low-level tx/rx pbuf queue.
 *
 */
#ifndef STELLARIS_NUM_PBUF_QUEUE
#define STELLARIS_NUM_PBUF_QUEUE    20
#endif

/**
 * Setup processing for PTP (IEEE-1588).
 *
 */
#if LWIP_PTPD
extern void lwIPHostGetTime(u32_t *time_s, u32_t *time_ns);
#endif

/**
 * Luminary Micro DriverLib Header Files required for this interface driver.
 *
 */
#include "hw_memmap.h"
#include "hw_types.h"
#include "hw_ints.h"
#include "hw_ethernet.h"
#include "ethernet.h"
#include "interrupt.h"
#include "sysctl.h"

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

/* Helper struct to hold a queue of pbufs for transmit and receive. */
struct pbufq {
  struct pbuf *pbuf[STELLARIS_NUM_PBUF_QUEUE];
  unsigned long qwrite;
  unsigned long qread;
  unsigned long overflow;
};

/* Helper macros for accessing pbuf queues. */
#define PBUF_QUEUE_EMPTY(q) \
    (((q)->qwrite == (q)->qread) ? true : false)

#define PBUF_QUEUE_FULL(q) \
    ((((((q)->qwrite + 1) % STELLARIS_NUM_PBUF_QUEUE)) == (q)->qread) ? \
    true : false )

/**
 * Helper struct to hold private data used to operate your ethernet interface.
 * Keeping the ethernet address of the MAC in this struct is not necessary
 * as it is already kept in the struct netif.
 * But this is only an example, anyway...
 */
struct ethernetif {
  struct eth_addr *ethaddr;
  /* Add whatever per-interface state that is needed here. */
  struct pbufq txq;
  struct pbufq rxq;
};

/**
 * Global variable for this interface's private data.  Needed to allow
 * the interrupt handlers access to this information outside of the
 * context of the lwIP netif.
 *
 */
static struct ethernetif ethernetif_data;

/**
 * Pop a pbuf packet from a pbuf packet queue
 *
 * @param q is the packet queue from which to pop the pbuf.
 *
 * @return pointer to pbuf packet if available, NULL otherswise.
 */
static struct pbuf *
dequeue_packet(struct pbufq *q)
{
  struct pbuf *pBuf;
  SYS_ARCH_DECL_PROTECT(lev);

  /**
   * This entire function must run within a "critical section" to preserve
   * the integrity of the transmit pbuf queue.
   *
   */
  SYS_ARCH_PROTECT(lev);

  if(PBUF_QUEUE_EMPTY(q)) {
    /* Return a NULL pointer if the queue is empty. */
    pBuf = (struct pbuf *)NULL;
  }
  else {
    /**
     * The queue is not empty so return the next frame from it
     * and adjust the read pointer accordingly.
     *
     */
    pBuf = q->pbuf[q->qread];
    q->qread = ((q->qread + 1) % STELLARIS_NUM_PBUF_QUEUE);
  }

  /* Return to prior interrupt state and return the pbuf pointer. */
  SYS_ARCH_UNPROTECT(lev);
  return(pBuf);
}

/**
 * Push a pbuf packet onto a pbuf packet queue
 *
 * @param p is the pbuf to push onto the packet queue.
 * @param q is the packet queue.
 *
 * @return 1 if successful, 0 if q is full.
 */
static int
enqueue_packet(struct pbuf *p, struct pbufq *q)
{
  SYS_ARCH_DECL_PROTECT(lev);
  int ret;

  /**
   * This entire function must run within a "critical section" to preserve
   * the integrity of the transmit pbuf queue.
   *
   */
  SYS_ARCH_PROTECT(lev);

  if(!PBUF_QUEUE_FULL(q)) {
    /**
     * The queue isn't full so we add the new frame at the current
     * write position and move the write pointer.
     *
     */
    q->pbuf[q->qwrite] = p;
    q->qwrite = ((q->qwrite + 1) % STELLARIS_NUM_PBUF_QUEUE);
    ret = 1;
  }
  else {
    /**
     * The stack is full so we are throwing away this value.  Keep track
     * of the number of times this happens.
     *
     */
    q->overflow++;
    ret = 0;
  }

  /* Return to prior interrupt state and return the pbuf pointer. */
  SYS_ARCH_UNPROTECT(lev);
  return(ret);
}

/**
 * In this function, the hardware should be initialized.
 * Called from stellarisif_init().
 *
 * @param netif the already initialized lwip network interface structure
 *        for this ethernetif
 */
static void
low_level_init(struct netif *netif)
{
  u32_t temp;
  //struct ethernetif *ethernetif = netif->state;

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

  /* set MAC hardware address */
  EthernetMACAddrGet(ETH_BASE, &(netif->hwaddr[0]));

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

  /* device capabilities */
  /* don't set NETIF_FLAG_ETHARP if this device is not an ethernet one */
  netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP;

  /* Do whatever else is needed to initialize interface. */
  /* Disable all Ethernet Interrupts. */
  EthernetIntDisable(ETH_BASE, (ETH_INT_PHY | ETH_INT_MDIO | ETH_INT_RXER |
     ETH_INT_RXOF | ETH_INT_TX | ETH_INT_TXER | ETH_INT_RX));
  temp = EthernetIntStatus(ETH_BASE, false);
  EthernetIntClear(ETH_BASE, temp);

  /* Initialize the Ethernet Controller. */
  EthernetInitExpClk(ETH_BASE, SysCtlClockGet());

  /*
   * Configure the Ethernet Controller for normal operation.
   * - Enable TX Duplex Mode
   * - Enable TX Padding
   * - Enable TX CRC Generation
   * - Enable RX Multicast Reception
   */
  EthernetConfigSet(ETH_BASE, (ETH_CFG_TX_DPLXEN |ETH_CFG_TX_CRCEN |
    ETH_CFG_TX_PADEN | ETH_CFG_RX_AMULEN));

  /* Enable the Ethernet Controller transmitter and receiver. */
  EthernetEnable(ETH_BASE);
  
  IntPrioritySet(INT_ETH, 0xFF);    /*設置以太網中斷優先級*/
  /* Enable the Ethernet Interrupt handler. */
  IntEnable(INT_ETH);

  /* Enable Ethernet TX and RX Packet Interrupts. */
  EthernetIntEnable(ETH_BASE, ETH_INT_RX | ETH_INT_TX);
}

/**
 * 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 This function MUST be called with interrupts disabled or with the
 *       Stellaris Ethernet transmit fifo protected.
 */
static err_t
low_level_transmit(struct netif *netif, struct pbuf *p)
{
  int iBuf;
  unsigned char *pucBuf;
  unsigned long *pulBuf;
  struct pbuf *q;
  int iGather;
  unsigned long ulGather;
  unsigned char *pucGather;

  /**
   * Fill in the first two bytes of the payload data (configured as padding
   * with ETH_PAD_SIZE = 2) with the total length of the payload data
   * (minus the Ethernet MAC layer header).
   *
   */
  *((unsigned short *)(p->payload)) = p->tot_len - 16;

  /* Initialize the gather register. */
  iGather = 0;
  pucGather = (unsigned char *)&ulGather;
  ulGather = 0;

  /* Copy data from the pbuf(s) into the TX Fifo. */
  for(q = p; q != NULL; q = q->next) {
    /* Intialize a char pointer and index to the pbuf payload data. */
    pucBuf = (unsigned char *)q->payload;
    iBuf = 0;

    /**
     * If the gather buffer has leftover data from a previous pbuf
     * in the chain, fill it up and write it to the Tx FIFO.
     *
     */
    while((iBuf < q->len) && (iGather != 0)) {
      /* Copy a byte from the pbuf into the gather buffer. */
      pucGather[iGather] = pucBuf[iBuf++];

      /* Increment the gather buffer index modulo 4. */
      iGather = ((iGather + 1) % 4);
    }

    /**
     * If the gather index is 0 and the pbuf index is non-zero,
     * we have a gather buffer to write into the Tx FIFO.
     *
     */
    if((iGather == 0) && (iBuf != 0)) {
      HWREG(ETH_BASE + MAC_O_DATA) = ulGather;
      ulGather = 0;
    }

    /* Initialze a long pointer into the pbuf for 32-bit access. */
    pulBuf = (unsigned long *)&pucBuf[iBuf];

    /**
     * Copy words of pbuf data into the Tx FIFO, but don't go past
     * the end of the pbuf.