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/* ethernet.c -- Simulation of Ethernet MAC

   Copyright (C) 2001 by Erez Volk, erez@opencores.org

                         Ivan Guzvinec, ivang@opencores.org

   Copyright (C) 2008, 2001 Embecosm Limited

   Copyright (C) 2010 ORSoC

   Contributor Jeremy Bennett <jeremy.bennett@embecosm.com>

   Contributor Julius Baxter <julius@orsoc.se>

   This file is part of Or1ksim, the OpenRISC 1000 Architectural Simulator.

   This program is free software; you can redistribute it and/or modify it

   under the terms of the GNU General Public License as published by the Free

   Software Foundation; either version 3 of the License, or (at your option)

   any later version.

   This program is distributed in the hope that it will be useful, but WITHOUT

   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for

   more details.

   You should have received a copy of the GNU General Public License along

   with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* This program is commented throughout in a fashion suitable for processing

   with Doxygen. */

/* Autoconf and/or portability configuration */

#include "config.h"

#include "port.h"

/* System includes */

#include <stdlib.h>

#include <stdio.h>

#include <sys/socket.h>

#include <sys/ioctl.h>

#include <sys/stat.h>

#include <sys/types.h>

#include <fcntl.h>

#include <sys/poll.h>

#include <unistd.h>

#include <errno.h>

#include <linux/if.h>

#include <linux/if_tun.h>

/* Package includes */

#include "arch.h"

#include "config.h"

#include "abstract.h"

#include "eth.h"

#include "dma.h"

#include "sim-config.h"

#include "fields.h"

#include "crc32.h"

#include "vapi.h"

#include "pic.h"

#include "sched.h"

#include "toplevel-support.h"

#include "sim-cmd.h"

/* Control debug messages */

#define ETH_DEBUG 0

#ifndef ETH_DEBUG

# define ETH_DEBUG  1

#endif

/*! MAC address that is always accepted. */

static const unsigned char mac_broadcast[ETHER_ADDR_LEN] =

  { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };

/* -------------------------------------------------------------------------- */

/*!Structure describing the Ethernet device                                   */

/* -------------------------------------------------------------------------- */

struct eth_device

{

  /* Basic stuff about the device */

  int                enabled;           /* Is peripheral enabled */

  oraddr_t           baseaddr;          /* Base address in memory */

  unsigned long int  base_vapi_id;      /* Start of VAPI ID block */

  /* DMA controller this MAC is connected to, and associated channels */

  unsigned dma;

  unsigned tx_channel;

  unsigned rx_channel;

  /* Details of the hardware */

  unsigned char      mac_address[ETHER_ADDR_LEN];  /* Ext HW address */

  unsigned long int  phy_addr;          /* Int HW address */

  unsigned long int  mac_int;           /* interrupt line number */

  int                int_line_stat;     /* interrupt line status */

  /* External interface deatils */

  int rtx_type;                         /* Type of external i/f: FILE or TAP */

  /* RX and TX file names and handles for FILE type connection. */

  char  *rxfile;                        /* Rx filename */

  char  *txfile;                        /* Tx filename */

  int    txfd;                          /* Rx file handle */

  int    rxfd;                          /* Tx file handle */

  /* Info for TAP type connections */

  char *tap_dev;                        /* The TAP device */

  int   rtx_fd;                         /* TAP device handle */

  /* Indices into the buffer descriptors. */

  unsigned long int  tx_bd_index;

  unsigned long int  rx_bd_index;

  /* Visible registers */

  struct

  {

    unsigned long int  moder;

    unsigned long int  int_source;

    unsigned long int  int_mask;

    unsigned long int  ipgt;

    unsigned long int  ipgr1;

    unsigned long int  ipgr2;

    unsigned long int  packetlen;

    unsigned long int  collconf;

    unsigned long int  tx_bd_num;

    unsigned long int  controlmoder;

    unsigned long int  miimoder;

    unsigned long int  miicommand;

    unsigned long int  miiaddress;

    unsigned long int  miitx_data;

    unsigned long int  miirx_data;

    unsigned long int  miistatus;

    unsigned long int  hash0;

    unsigned long int  hash1;

    /* Buffer descriptors */

    unsigned long int  bd_ram[ETH_BD_SPACE / 4];

  } regs;

};

/* -------------------------------------------------------------------------- */

/*!Emulate MIIM transaction to ethernet PHY

   @param[in]  eth  Ethernet device datastruture.                           */

/* -------------------------------------------------------------------------- */

static void

eth_miim_trans (struct eth_device *eth)

{

  switch (eth->regs.miicommand)

    {

    case ((1 << ETH_MIICOMM_WCDATA_OFFSET)):

      /* Perhaps something to emulate here later, but for now do nothing */

      break;

    case ((1 << ETH_MIICOMM_RSTAT_OFFSET)):

      /*

      printf("or1ksim: eth_miim_trans: phy %d\n",(int)

             ((eth->regs.miiaddress >> ETH_MIIADDR_FIAD_OFFSET)&

              ETH_MIIADDR_FIAD_MASK));

      printf("or1ksim: eth_miim_trans: reg %d\n",(int)

             ((eth->regs.miiaddress >> ETH_MIIADDR_RGAD_OFFSET)&

              ETH_MIIADDR_RGAD_MASK));

      */

      /*First check if it's the correct PHY to address */

      if (((eth->regs.miiaddress >> ETH_MIIADDR_FIAD_OFFSET)&

           ETH_MIIADDR_FIAD_MASK) == eth->phy_addr)

        {

          /* Correct PHY - now switch based on the register address in the PHY*/

          switch ((eth->regs.miiaddress >> ETH_MIIADDR_RGAD_OFFSET)&

                  ETH_MIIADDR_RGAD_MASK)

            {

            case MII_BMCR:

              eth->regs.miirx_data = BMCR_FULLDPLX;

              break;

            case MII_BMSR:

              eth->regs.miirx_data = BMSR_LSTATUS | BMSR_ANEGCOMPLETE |

                BMSR_10HALF | BMSR_10FULL | BMSR_100HALF | BMSR_100FULL;

              break;

            case MII_PHYSID1:

              eth->regs.miirx_data = 0x22; /* Micrel PHYID */

              break;

            case MII_PHYSID2:

              eth->regs.miirx_data = 0x1613; /* Micrel PHYID */

              break;

            case MII_ADVERTISE:

              eth->regs.miirx_data = ADVERTISE_FULL;

              break;

            case MII_LPA:

              eth->regs.miirx_data = LPA_DUPLEX | LPA_100;

              break;

            case MII_EXPANSION:

              eth->regs.miirx_data = 0;

              break;

            case MII_CTRL1000:

              eth->regs.miirx_data = 0;

              break;

            case MII_STAT1000:

              eth->regs.miirx_data = 0;

              break;

            case MII_ESTATUS:

              eth->regs.miirx_data = 0;

              break;

            case MII_DCOUNTER:

              eth->regs.miirx_data = 0;

              break;

            case MII_FCSCOUNTER:

              eth->regs.miirx_data = 0;

              break;

            case MII_NWAYTEST:

              eth->regs.miirx_data = 0;

              break;

            case MII_RERRCOUNTER:

              eth->regs.miirx_data = 0;

              break;

            case MII_SREVISION:

              eth->regs.miirx_data = 0;

              break;

            case MII_RESV1:

              eth->regs.miirx_data = 0;

              break;

            case MII_LBRERROR:

              eth->regs.miirx_data = 0;

              break;

            case MII_PHYADDR:

              eth->regs.miirx_data = eth->phy_addr;

              break;

            case MII_RESV2:

              eth->regs.miirx_data = 0;

              break;

            case MII_TPISTATUS:

              eth->regs.miirx_data = 0;

              break;

            case MII_NCONFIG:

              eth->regs.miirx_data = 0;

              break;

            default:

              eth->regs.miirx_data = 0xffff;

              break;

            }

        }

      else

        {

          eth->regs.miirx_data = 0xffff; /* PHY doesn't exist, read all 1's */

        }

      break;

    case ((1 << ETH_MIICOMM_SCANS_OFFSET)):

      /* From MAC's datasheet:

         A host initiates the Scan Status Operation by asserting the SCANSTAT

         signal. The MIIM performs a continuous read operation of the PHY

         Status register. The PHY is selected by the FIAD[4:0] signals. The

         link status LinkFail signal is asserted/deasserted by the MIIM module

         and reflects the link status bit of the PHY Status register. The

         signal NVALID is used for qualifying the validity of the LinkFail

         signals and the status data PRSD[15:0]. These signals are invalid

         until the first scan status operation ends. During the scan status

         operation, the BUSY signal is asserted until the last read is

         performed (the scan status operation is stopped).

         So for now - do nothing, leave link status indicator as permanently

         with link.

      */

      break;

    default:

      break;

    }

}       /* eth_miim_trans () */

/* -------------------------------------------------------------------------- */

/*!Write an Ethernet packet to a FILE interface.

   This writes a single Ethernet packet to a FILE interface. The format is to

   write the length, then the data.

   @param[in] eth     Pointer to the relevant Ethernet data structure.

   @param[in] buf     Where to get the data.

   @param[in] length  Length of data to write.

   @return  The length if successful, a negative value otherwise.             */

/* -------------------------------------------------------------------------- */

static ssize_t

eth_write_file_packet (struct eth_device *eth,

                       unsigned char     *buf,

                       unsigned long int  length)

{

  ssize_t  nwritten;

  /* Write length to file. */

  nwritten = write (eth->txfd, &(length), sizeof (length));

  if (nwritten != sizeof (length))

    {

      fprintf (stderr, "ERROR: Failed to write Ethernet packet length: %s.\n",

               strerror (errno));

      return  -1;

    }

  /* write data to file */

  nwritten = write (eth->txfd, buf, length);

  if (nwritten != length)

    {

      fprintf (stderr, "ERROR: Failed to write Ethernet packet data: %s.\n",

               strerror (errno));

      return  -1;

    }

  return  nwritten;

}       /* eth_write_file_packet () */

/* -------------------------------------------------------------------------- */

/*!Write an Ethernet packet to a TAP interface.

   This writes a single Ethernet packet to a TAP interface.

   @param[in] eth     Pointer to the relevant Ethernet data structure.

   @param[in] buf     Where to get the data.

   @param[in] length  Length of data to write.

   @return  The length if successful, a negative value otherwise.             */

/* -------------------------------------------------------------------------- */

static ssize_t

eth_write_tap_packet (struct eth_device *eth,

                      unsigned char     *buf,

                      unsigned long int  length)

{

  ssize_t  nwritten;

#if ETH_DEBUG

  int  j;

  printf ("Writing TAP\n");

  printf ("  packet %d bytes:", (int) length);

  for (j = 0; j < length; j++)

    {

      if (0 == (j % 16))

        {

          printf ("\n");

        }

      else if (0 == (j % 8))

        {

          printf (" ");

        }

      printf ("%.2x ", buf[j]);

    }

  printf("\nend packet:\n");

#endif    

  /* Write the data to the TAP */

  nwritten = write (eth->rtx_fd, buf, length);

  if (nwritten != length)

    {

      fprintf (stderr, "ERROR: Failed to write Ethernet packet data: %s.\n",

               strerror (errno));

      return  -1;

    }

  return  nwritten;

}       /* eth_write_tap_packet () */

/* -------------------------------------------------------------------------- */

/*!Write an Ethernet packet.

   This writes a single Ethernet packet to the outside world from the supplied

   buffer. It deals with the different types of external interface.

   @param[in] eth     Pointer to the relevant Ethernet data structure.

   @param[in] buf     Where to get the data.

   @param[in] length  Length of data to write.

   @return  The length if successful, zero if no packet was available,

            a negative value otherwise.                                       */

/* -------------------------------------------------------------------------- */

static ssize_t

eth_write_packet (struct eth_device *eth,

                  unsigned char     *buf,

                  ssize_t            length)

{

  /* Send packet according to interface type. */

  switch (eth->rtx_type)

    {

    case ETH_RTX_FILE: return  eth_write_file_packet (eth, buf, length);

    case ETH_RTX_TAP:  return  eth_write_tap_packet (eth, buf, length);

    default:

      fprintf (stderr, "Unknown Ethernet write interface: ignored.\n");

      return  (ssize_t) -1;

    }

}       /* eth_write_packet () */

/* -------------------------------------------------------------------------- */

/*!Flush a Tx buffer descriptor to the outside world.

   We know the buffer descriptor is full, so write it to the appropriate

   outside interface.

   @param[in] eth  The Ethernet data structure.                               */

/* -------------------------------------------------------------------------- */

static void

eth_flush_bd (struct eth_device *eth)

{

  /* First word of BD is flags and length, second is pointer to buffer */

  unsigned long int  bd_info = eth->regs.bd_ram[eth->tx_bd_index];

  unsigned long int  bd_addr = eth->regs.bd_ram[eth->tx_bd_index + 1];

  unsigned char      buf[ETH_MAXPL];

  long int           packet_length;

  long int           bytes_sent;

  /* Get the packet length */

  packet_length = GET_FIELD (bd_info, ETH_TX_BD, LENGTH);

  /* Clear error status bits and retry count. */

  CLEAR_FLAG (bd_info, ETH_TX_BD, DEFER);

  CLEAR_FLAG (bd_info, ETH_TX_BD, COLLISION);

  CLEAR_FLAG (bd_info, ETH_TX_BD, RETRANSMIT);

  CLEAR_FLAG (bd_info, ETH_TX_BD, UNDERRUN);

  CLEAR_FLAG (bd_info, ETH_TX_BD, NO_CARRIER);

  SET_FIELD (bd_info, ETH_TX_BD, RETRY, 0);

  /* Copy data from buffer descriptor address into our local buf. */

  for (bytes_sent = 0; bytes_sent < packet_length; bytes_sent +=4)

    {

      unsigned long int  read_word =

        eval_direct32 (bytes_sent + bd_addr, 0, 0);

      buf[bytes_sent]     = (unsigned char) (read_word >> 24);

      buf[bytes_sent + 1] = (unsigned char) (read_word >> 16);

      buf[bytes_sent + 2] = (unsigned char) (read_word >> 8);

      buf[bytes_sent + 3] = (unsigned char) (read_word);

    }

  /* Send packet according to interface type and set BD status. If we didn't

     write the whole packet, then we retry. */

  if (eth_write_packet (eth, buf, packet_length) == packet_length)

    {

      CLEAR_FLAG (bd_info, ETH_TX_BD, READY);

      SET_FLAG (eth->regs.int_source, ETH_INT_SOURCE, TXB);

    }

  else

    {

      /* Does this retry mechanism really work? */

      CLEAR_FLAG (bd_info, ETH_TX_BD, READY);

      CLEAR_FLAG (bd_info, ETH_TX_BD, COLLISION);

      SET_FLAG (eth->regs.int_source, ETH_INT_SOURCE, TXE);

#if ETH_DEBUG

      printf ("Transmit retry request.\n");

#endif

    }

  /* Update the flags in the buffer descriptor */

  eth->regs.bd_ram[eth->tx_bd_index] = bd_info;

  /* Generate interrupt to indicate transfer complete, under the

     following criteria all being met:

     - either INT_MASK flag for Tx (OK or error) is set

     - the bugger descriptor has its IRQ flag set

     - there is no interrupt in progress.

     @todo We ought to warn if we get here and fail to set an IRQ. */

  if ((TEST_FLAG (eth->regs.int_mask, ETH_INT_MASK, TXE_M) ||

       TEST_FLAG (eth->regs.int_mask, ETH_INT_MASK, TXB_M)) &&

      TEST_FLAG (bd_info, ETH_TX_BD, IRQ))

    {

      if (eth->int_line_stat)

        {

          fprintf (stderr, "Warning: Interrupt active during Tx.\n");

        }

      else

        {

#if ETH_DEBUG

          printf ("TRANSMIT interrupt\n");

#endif

          report_interrupt (eth->mac_int);

          eth->int_line_stat = 1;

        }

    }

  /* Advance to next BD, wrapping around if appropriate. */

  if (TEST_FLAG (bd_info, ETH_TX_BD, WRAP) ||

      eth->tx_bd_index >= ((eth->regs.tx_bd_num - 1) * 2))

    {

      eth->tx_bd_index = 0;

    }

  else

    {

      eth->tx_bd_index += 2;

    }

}       /* eth_flush_bd () */

/* -------------------------------------------------------------------------- */

/*!Tx clock function.

   Responsible for starting and completing any TX actions.

   The original version had 4 states, which allowed modeling the transfer of

   data one byte per cycle.  For now we use only the one state for

   efficiency. When we find something in a buffer descriptor, we transmit

   it.

   We reschedule every cycle. There is no point in trying to do anything if

   there is an interrupt still being processed by the core.

   @todo We should eventually reinstate the one byte per cycle transfer.

   @param[in] dat  The Ethernet data structure, passed as a void pointer.    */

/* -------------------------------------------------------------------------- */

static void

eth_controller_tx_clock (void *dat)

{

  struct eth_device *eth = dat;

  /* Only do anything if there is not an interrupt outstanding. */

  if (!eth->int_line_stat)

    {

      /* First word of BD is flags. If we have a buffer ready, get it and

         transmit it. */

      if (TEST_FLAG (eth->regs.bd_ram[eth->tx_bd_index], ETH_TX_BD, READY))

        {

          eth_flush_bd (eth);

        }

    }

  /* Wake up again after 1 ticks (was 10, changed by Julius). */

  SCHED_ADD (eth_controller_tx_clock, dat, 1);

}       /* eth_controller_tx_clock () */

/* -------------------------------------------------------------------------- */

/*!Read an Ethernet packet from a FILE interface.

   This reads a single Ethernet packet from the outside world via a FILE

   interface.

   The format is 4 bytes of packet length, followed by the packet data.

   @param[in]  eth  Pointer to the relevant Ethernet data structure

   @param[out] buf  Where to put the data

   @return  The length if successful, zero if no packet was available

            (i.e. EOF), a negative value otherwise.                           */

/* -------------------------------------------------------------------------- */

static ssize_t

eth_read_file_packet (struct eth_device *eth,

                      unsigned char     *buf)

{

  ssize_t  packet_length;

  ssize_t  nread;

  /* Read packet length. We may be at EOF. */

  nread = read (eth->rxfd, &(packet_length), sizeof (packet_length));

  if (0 == nread)

    {

      return  0;                 /* No more packets */

    }

  else if (nread < sizeof (packet_length))

    {

      fprintf (stderr, "ERROR: Failed to read length from file.\n");

      return  -1;

    }

  /* Packet must be big enough to hold a header */

  if (packet_length < ETHER_HDR_LEN)

    {

      fprintf (stderr, "Warning: Ethernet packet length %zd too small.\n",

               packet_length);

      return  -1;

    }

  /* Read the packet proper. */

  nread = read (eth->rxfd, buf, packet_length);

  if (nread != packet_length)

    {

      fprintf (stderr, "ERROR: Failed to read packet from file.\n");

      return  -1;

    }

  return  packet_length;

}       /* eth_read_file_packet () */

/* -------------------------------------------------------------------------- */

/*!Read an Ethernet packet from a FILE interface.

   This reads a single Ethernet packet from the outside world via a TAP

   interface.

   A complete packet is always read, so its length (minus CRC) is the amount

   read.

   @param[in]  eth  Pointer to the relevant Ethernet data structure

   @param[out] buf  Where to put the data

   @return  The length if successful, zero if no packet was available,

            a negative value otherwise.                                       */

/* -------------------------------------------------------------------------- */

static ssize_t

eth_read_tap_packet (struct eth_device *eth,

                     unsigned char     *buf)

{

  struct pollfd  fds[1];

  int            n;

  ssize_t        packet_length;

  /* Poll to see if there is data to read */

  fds[0].fd     = eth->rtx_fd;

  fds[0].events = POLLIN;

  n = poll (fds, 1, 0);

  if (n < 0)

    {

      fprintf (stderr, "Warning: Poll for TAP receive failed %s: ignored.\n",

               strerror (errno));

      return  -1;

    }

  else if ((n > 0) && ((fds[0].revents & POLLIN) == POLLIN))

    {

      /* Data to be read from TAP */

      packet_length = read (eth->rtx_fd, buf, ETH_MAXPL);

#if ETH_DEBUG

      printf ("%d bytes read from TAP.\n", (int) packet_length);

#endif

      if (packet_length < 0)

        {

          fprintf (stderr, "Warning: Read of RXTATE_RECV failed: %s.\n",

                   strerror (errno));

          SET_FLAG (eth->regs.int_source, ETH_INT_SOURCE, RXE);

          /* Signal interrupt if enabled, and no interrupt currently in

             progress. */

          if (TEST_FLAG (eth->regs.int_mask, ETH_INT_MASK, RXE_M) &&

              !eth->int_line_stat)

            {

#if ETH_DEBUG

              printf ("Ethernet failed receive interrupt\n");

#endif

              report_interrupt (eth->mac_int);

              eth->int_line_stat = 1;

            }

        }

      return  packet_length;

    }

  else

    {

      return  0;                 /* No packet */

    }

}       /* eth_read_tap_packet () */

/* -------------------------------------------------------------------------- */

/*!Read an Ethernet packet.

   This reads a single Ethernet packet from the outside world into the

   supplied buffer. It deals with the different types of external interface.

   @param[in]  eth  Pointer to the relevant Ethernet data structure

   @param[out] buf  Where to put the data

   @return  The length if successful, zero if no packet was available,

            a negative value otherwise.                                       */

/* -------------------------------------------------------------------------- */

static ssize_t

eth_read_packet (struct eth_device *eth,

                 unsigned char     *buf)

{

  switch (eth->rtx_type)

    {

    case ETH_RTX_FILE: return  eth_read_file_packet (eth, buf);

    case ETH_RTX_TAP:  return  eth_read_tap_packet (eth, buf);

    default:

      fprintf (stderr, "Unknown Ethernet read interface: ignored.\n");

      return  (ssize_t) -1;

    }

}       /* eth_read_packet () */

/* -------------------------------------------------------------------------- */

/*!Fill a buffer descriptor