// This file is Copyright (c) 2015 Florent Kermarrec <florent@enjoy-digital.fr>
// LiteETH lwIP port for ARTIQ
// License: BSD

#include <lwip/opt.h>
#include <lwip/mem.h>

#include <netif/etharp.h>
#include "netif/liteethif.h"

#include <generated/csr.h>
#include <hw/flags.h>
#include <hw/ethmac_mem.h>

typedef union {
  unsigned char raw[1514];
} ethernet_buffer;

static unsigned int rxslot;
static unsigned int rxlen;
static ethernet_buffer *rxbuffer;
static ethernet_buffer *rxbuffer0;
static ethernet_buffer *rxbuffer1;
static unsigned int txslot;
static unsigned int txlen;
static ethernet_buffer *txbuffer;
static ethernet_buffer *txbuffer0;
static ethernet_buffer *txbuffer1;

#define IFNAME0 'e'
#define IFNAME1 't'

static void liteeth_low_level_init(struct netif *netif)
{
  int i;

  netif->hwaddr_len = 6;
  for(i=0;i<netif->hwaddr_len;i++)
    netif->hwaddr[i] = macadr[i];
  netif->mtu = 1514;
  netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP;

  ethmac_sram_reader_ev_pending_write(ETHMAC_EV_SRAM_READER);
  ethmac_sram_writer_ev_pending_write(ETHMAC_EV_SRAM_WRITER);

  rxbuffer0 = (ethernet_buffer *)ETHMAC_RX0_BASE;
  rxbuffer1 = (ethernet_buffer *)ETHMAC_RX1_BASE;
  txbuffer0 = (ethernet_buffer *)ETHMAC_TX0_BASE;
  txbuffer1 = (ethernet_buffer *)ETHMAC_TX1_BASE;

  rxslot = 0;
  txslot = 0;

  rxbuffer = rxbuffer0;
  txbuffer = txbuffer0;

  return;
}

static err_t liteeth_low_level_output(struct netif *netif, struct pbuf *p)
{
  struct pbuf *q;

  txlen = 0;
  for(q = p; q != NULL; q = q->next) {
    memcpy(txbuffer->raw, q->payload, q->len);
    txbuffer += q->len;
    txlen += q->len;
  }

  ethmac_sram_reader_slot_write(txslot);
  ethmac_sram_reader_length_write(txlen);
  while(!(ethmac_sram_reader_ready_read()));
  ethmac_sram_reader_start_write(1);

  txslot = (txslot+1)%2;
  if (txslot)
    txbuffer = txbuffer1;
  else
    txbuffer = txbuffer0;

  return ERR_OK;
}

static struct pbuf * liteeth_low_level_input(struct netif *netif)
{
  struct pbuf *p, *q;

  rxslot = ethmac_sram_writer_slot_read();
  rxlen = ethmac_sram_writer_length_read();
  if (rxslot)
      rxbuffer = rxbuffer1;
    else
      rxbuffer = rxbuffer0;

  p = pbuf_alloc(PBUF_RAW, rxlen, PBUF_POOL);
  if (p != NULL) {
    for(q = p; q != NULL; q = q->next) {
       memcpy(q->payload, rxbuffer->raw, q->len);
       rxbuffer += q->len;
    }
  }

  return p;
}

void liteeth_input(struct netif *netif)
{
  struct pbuf *p;
  p = liteeth_low_level_input(netif);
  if (p != NULL) {
    netif->input(p, netif);
  }
}

err_t liteeth_init(struct netif *netif)
{
  struct liteethif *liteethif;

  liteethif = mem_malloc(sizeof(struct liteethif));
  if (liteethif == NULL)
    return ERR_MEM;
  netif->state = liteethif;

  netif->hwaddr_len = 6;
  netif->name[0] = IFNAME0;
  netif->name[1] = IFNAME1;
  netif->output = etharp_output;
  netif->linkoutput = liteeth_low_level_output;
  netif->mtu = 1514;

  liteethif->ethaddr = (struct eth_addr *)&(netif->hwaddr[0]);

  liteeth_low_level_init(netif);

  return ERR_OK;
}