/*
    ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
                 2011,2012 Giovanni Di Sirio.

    This file is part of ChibiOS/RT.

    ChibiOS/RT 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.

    ChibiOS/RT 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/>.

                                      ---

    A special exception to the GPL can be applied should you wish to distribute
    a combined work that includes ChibiOS/RT, without being obliged to provide
    the source code for any proprietary components. See the file exception.txt
    for full details of how and when the exception can be applied.
*/

/**
 * @file    AT91SAM7/mac_lld.c
 * @brief   AT91SAM7 low level MAC driver code.
 *
 * @addtogroup MAC
 * @{
 */

#include <string.h>

#include "ch.h"
#include "hal.h"
#include "mii.h"
#include "at91sam7_mii.h"

#if HAL_USE_MAC || defined(__DOXYGEN__)

#define EMAC_PIN_MASK (AT91C_PB0_ETXCK_EREFCK  | AT91C_PB1_ETXEN         | \
                       AT91C_PB2_ETX0          | AT91C_PB3_ETX1          | \
                       AT91C_PB4_ECRS          | AT91C_PB5_ERX0          | \
                       AT91C_PB6_ERX1          | AT91C_PB7_ERXER         | \
                       AT91C_PB8_EMDC          | AT91C_PB9_EMDIO         | \
                       AT91C_PB10_ETX2         | AT91C_PB11_ETX3         | \
                       AT91C_PB12_ETXER        | AT91C_PB13_ERX2         | \
                       AT91C_PB14_ERX3         | AT91C_PB15_ERXDV_ECRSDV | \
                       AT91C_PB16_ECOL         | AT91C_PB17_ERXCK)

#define RSR_BITS (AT91C_EMAC_BNA | AT91C_EMAC_REC | AT91C_EMAC_OVR)

#define TSR_BITS (AT91C_EMAC_UBR | AT91C_EMAC_COL | AT91C_EMAC_RLES | \
                  AT91C_EMAC_BEX | AT91C_EMAC_COMP | AT91C_EMAC_UND)

/*===========================================================================*/
/* Driver exported variables.                                                */
/*===========================================================================*/

/**
 * @brief   Ethernet driver 1.
 */
MACDriver ETHD1;

/*===========================================================================*/
/* Driver local variables.                                                   */
/*===========================================================================*/

#ifndef __DOXYGEN__

static uint8_t default_mac[] = {0xAA, 0x55, 0x13, 0x37, 0x01, 0x10};

static EMACDescriptor *rxptr;
static EMACDescriptor *txptr;
static EMACDescriptor rd[EMAC_RECEIVE_DESCRIPTORS]
    __attribute__((aligned(8)));
static EMACDescriptor td[EMAC_TRANSMIT_DESCRIPTORS]
    __attribute__((aligned(8)));
static uint8_t rb[EMAC_RECEIVE_DESCRIPTORS * EMAC_RECEIVE_BUFFERS_SIZE]
    __attribute__((aligned(8)));
static uint8_t tb[EMAC_TRANSMIT_DESCRIPTORS * EMAC_TRANSMIT_BUFFERS_SIZE]
    __attribute__((aligned(8)));
#endif

/*===========================================================================*/
/* Driver local functions.                                                   */
/*===========================================================================*/

/**
 * @brief   IRQ handler.
 */
/** @cond never*/
__attribute__((noinline))
/** @endcond*/
static void serve_interrupt(void) {
  uint32_t isr, rsr, tsr;

  /* Fix for the EMAC errata */
  isr = AT91C_BASE_EMAC->EMAC_ISR;
  rsr = AT91C_BASE_EMAC->EMAC_RSR;
  tsr = AT91C_BASE_EMAC->EMAC_TSR;

  if ((isr & AT91C_EMAC_RCOMP) || (rsr & RSR_BITS)) {
    if (rsr & AT91C_EMAC_REC) {
      chSysLockFromIsr();
      chSemResetI(&ETHD1.rdsem, 0);
#if MAC_USE_EVENTS
      chEvtBroadcastI(&ETHD1.rdevent);
#endif
      chSysUnlockFromIsr();
    }
    AT91C_BASE_EMAC->EMAC_RSR = RSR_BITS;
  }

  if ((isr & AT91C_EMAC_TCOMP) || (tsr & TSR_BITS)) {
    if (tsr & AT91C_EMAC_COMP) {
      chSysLockFromIsr();
      chSemResetI(&ETHD1.tdsem, 0);
      chSysUnlockFromIsr();
    }
    AT91C_BASE_EMAC->EMAC_TSR = TSR_BITS;
  }
  AT91C_BASE_AIC->AIC_EOICR = 0;
}

/**
 * @brief   Cleans an incomplete frame.
 *
 * @param[in] from      the start position of the incomplete frame
 */
static void cleanup(EMACDescriptor *from) {

  while (from != rxptr) {
    from->w1 &= ~W1_R_OWNERSHIP;
    if (++from >= &rd[EMAC_RECEIVE_DESCRIPTORS])
      from = rd;
  }
}

/**
 * @brief   MAC address setup.
 *
 * @param[in] p         pointer to a six bytes buffer containing the MAC
 *                      address
 */
static void set_address(const uint8_t *p) {

  AT91C_BASE_EMAC->EMAC_SA1L = (AT91_REG)((p[3] << 24) | (p[2] << 16) |
                                          (p[1] << 8) | p[0]);
  AT91C_BASE_EMAC->EMAC_SA1H = (AT91_REG)((p[5] << 8) | p[4]);
}

/*===========================================================================*/
/* Driver interrupt handlers.                                                */
/*===========================================================================*/

/**
 * @brief   EMAC IRQ handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(irq_handler) {

  CH_IRQ_PROLOGUE();

  serve_interrupt();

  CH_IRQ_EPILOGUE();
}

/*===========================================================================*/
/* Driver exported functions.                                                */
/*===========================================================================*/

/**
 * @brief   Low level MAC initialization.
 *
 * @notapi
 */
void mac_lld_init(void) {

  miiInit();
  macObjectInit(&ETHD1);

  /*
   * Associated PHY initialization.
   */
  miiReset(&ETHD1);

  /*
   * EMAC pins setup. Note, PB18 is not included because it is
   * used as #PD control and not as EF100.
   */
  AT91C_BASE_PIOB->PIO_ASR = EMAC_PIN_MASK;
  AT91C_BASE_PIOB->PIO_PDR = EMAC_PIN_MASK;
  AT91C_BASE_PIOB->PIO_PPUDR = EMAC_PIN_MASK;
}

/**
 * @brief   Configures and activates the MAC peripheral.
 *
 * @param[in] macp      pointer to the @p MACDriver object
 *
 * @notapi
 */
void mac_lld_start(MACDriver *macp) {
  unsigned i;

  /*
   * Buffers initialization.
   */
  for (i = 0; i < EMAC_RECEIVE_DESCRIPTORS; i++) {
    rd[i].w1 = (uint32_t)&rb[i * EMAC_RECEIVE_BUFFERS_SIZE];
    rd[i].w2 = 0;
  }
  rd[EMAC_RECEIVE_DESCRIPTORS - 1].w1 |= W1_R_WRAP;
  rxptr = rd;
  for (i = 0; i < EMAC_TRANSMIT_DESCRIPTORS; i++) {
    td[i].w1 = (uint32_t)&tb[i * EMAC_TRANSMIT_BUFFERS_SIZE];
    td[i].w2 = EMAC_TRANSMIT_BUFFERS_SIZE | W2_T_LAST_BUFFER | W2_T_USED;
  }
  td[EMAC_TRANSMIT_DESCRIPTORS - 1].w2 |= W2_T_WRAP;
  txptr = td;

  /*
   * EMAC clock enable.
   */
  AT91C_BASE_PMC->PMC_PCER = 1 << AT91C_ID_EMAC;

  /*
   * EMAC Initial setup.
   */
  AT91C_BASE_EMAC->EMAC_NCR = 0;                /* Stopped but MCE active.*/
  AT91C_BASE_EMAC->EMAC_NCFGR = 2 << 10;        /* MDC-CLK = MCK / 32 */
  AT91C_BASE_EMAC->EMAC_USRIO = AT91C_EMAC_CLKEN;/* Enable EMAC in MII mode.*/
  AT91C_BASE_EMAC->EMAC_RBQP = (AT91_REG)rd;    /* RX descriptors list.*/
  AT91C_BASE_EMAC->EMAC_TBQP = (AT91_REG)td;    /* TX descriptors list.*/
  AT91C_BASE_EMAC->EMAC_RSR = AT91C_EMAC_OVR |
                              AT91C_EMAC_REC |
                              AT91C_EMAC_BNA;   /* Clears RSR.*/
  AT91C_BASE_EMAC->EMAC_NCFGR |= AT91C_EMAC_DRFCS;/* Initial NCFGR settings.*/
  AT91C_BASE_EMAC->EMAC_NCR |= AT91C_EMAC_TE |
                               AT91C_EMAC_RE |
                               AT91C_EMAC_CLRSTAT;/* Initial NCR settings.*/
  if (macp->config->mac_address == NULL)
    set_address(default_mac);
  else
    set_address(macp->config->mac_address);

  /*
   * PHY device identification.
   */
  AT91C_BASE_EMAC->EMAC_NCR |= AT91C_EMAC_MPE;
  if ((miiGet(&ETHD1, MII_PHYSID1) != (PHY_ID >> 16)) ||
      ((miiGet(&ETHD1, MII_PHYSID2) & 0xFFF0) != (PHY_ID & 0xFFF0)))
    chSysHalt();
  AT91C_BASE_EMAC->EMAC_NCR &= ~AT91C_EMAC_MPE;

  /*
   * Interrupt configuration.
   */
  AT91C_BASE_EMAC->EMAC_IER = AT91C_EMAC_RCOMP | AT91C_EMAC_TCOMP;
  AIC_ConfigureIT(AT91C_ID_EMAC,
                  AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL | EMAC_INTERRUPT_PRIORITY,
                  irq_handler);
  AIC_EnableIT(AT91C_ID_EMAC);
}

/**
 * @brief   Deactivates the MAC peripheral.
 *
 * @param[in] macp      pointer to the @p MACDriver object
 *
 * @notapi
 */
void mac_lld_stop(MACDriver *macp) {

  (void)macp;
}

/**
 * @brief   Returns a transmission descriptor.
 * @details One of the available transmission descriptors is locked and
 *          returned.
 *
 * @param[in] macp      pointer to the @p MACDriver object
 * @param[out] tdp      pointer to a @p MACTransmitDescriptor structure
 * @return              The operation status.
 * @retval RDY_OK       the descriptor has been obtained.
 * @retval RDY_TIMEOUT  descriptor not available.
 *
 * @notapi
 */
msg_t mac_lld_get_transmit_descriptor(MACDriver *macp,
                                      MACTransmitDescriptor *tdp) {
  EMACDescriptor *edp;

  (void)macp;

  if (!macp->link_up)
    return RDY_TIMEOUT;

  chSysLock();
  edp = txptr;
  if (!(edp->w2 & W2_T_USED) || (edp->w2 & W2_T_LOCKED)) {
    chSysUnlock();
    return RDY_TIMEOUT;
  }
  /*
   * Set the buffer size and configuration, the buffer is also marked
   * as locked.
   */
  if (++txptr >= &td[EMAC_TRANSMIT_DESCRIPTORS]) {
    edp->w2 = W2_T_LOCKED | W2_T_USED | W2_T_LAST_BUFFER | W2_T_WRAP;
    txptr = td;
  }
  else
    edp->w2 = W2_T_LOCKED | W2_T_USED | W2_T_LAST_BUFFER;
  chSysUnlock();
  tdp->offset = 0;
  tdp->size = EMAC_TRANSMIT_BUFFERS_SIZE;
  tdp->physdesc = edp;
  return RDY_OK;
}

/**
 * @brief   Writes to a transmit descriptor's stream.
 *
 * @param[in] tdp       pointer to a @p MACTransmitDescriptor structure
 * @param[in] buf       pointer to the buffer containing the data to be
 *                      written
 * @param[in] size      number of bytes to be written
 * @return              The number of bytes written into the descriptor's
 *                      stream, this value can be less than the amount
 *                      specified in the parameter @p size if the maximum
 *                      frame size is reached.
 *
 * @notapi
 */
size_t mac_lld_write_transmit_descriptor(MACTransmitDescriptor *tdp,
                                         uint8_t *buf,
                                         size_t size) {

  if (size > tdp->size - tdp->offset)
    size = tdp->size - tdp->offset;
  if (size > 0) {
    memcpy((uint8_t *)(tdp->physdesc->w1 & W1_T_ADDRESS_MASK) +
                      tdp->offset,
           buf, size);
    tdp->offset += size;
  }
  return size;
}

/**
 * @brief   Releases a transmit descriptor and starts the transmission of the
 *          enqueued data as a single frame.
 *
 * @param[in] tdp       the pointer to the @p MACTransmitDescriptor structure
 *
 * @notapi
 */
void mac_lld_release_transmit_descriptor(MACTransmitDescriptor *tdp) {

  chSysLock();
  tdp->physdesc->w2 = (tdp->physdesc->w2 &
                          ~(W2_T_LOCKED | W2_T_USED | W2_T_LENGTH_MASK)) |
                         tdp->offset;
  AT91C_BASE_EMAC->EMAC_NCR |= AT91C_EMAC_TSTART;
  chSysUnlock();
}

/**
 * @brief   Returns a receive descriptor.
 *
 * @param[in] macp      pointer to the @p MACDriver object
 * @param[out] rdp      pointer to a @p MACReceiveDescriptor structure
 * @return              The operation status.
 * @retval RDY_OK       the descriptor has been obtained.
 * @retval RDY_TIMEOUT  descriptor not available.
 *
 * @notapi
 */
msg_t mac_lld_get_receive_descriptor(MACDriver *macp,
                                     MACReceiveDescriptor *rdp) {
  unsigned n;
  EMACDescriptor *edp;

  (void)macp;
  n = EMAC_RECEIVE_DESCRIPTORS;

  /*
   * Skips unused buffers, if any.
   */
skip:
  while ((n > 0) && !(rxptr->w1 & W1_R_OWNERSHIP)) {
    if (++rxptr >= &rd[EMAC_RECEIVE_DESCRIPTORS])
      rxptr = rd;
    n--;
  }

  /*
   * Skips fragments, if any, cleaning them up.
   */
  while ((n > 0) && (rxptr->w1 & W1_R_OWNERSHIP) &&
                    !(rxptr->w2 & W2_R_FRAME_START)) {
    rxptr->w1 &= ~W1_R_OWNERSHIP;
    if (++rxptr >= &rd[EMAC_RECEIVE_DESCRIPTORS])
      rxptr = rd;
    n--;
  }

  /*
   * Now compute the total frame size skipping eventual incomplete frames
   * or holes...
   */
restart:
  edp = rxptr;
  while (n > 0) {
    if (!(rxptr->w1 & W1_R_OWNERSHIP)) {
      /* Empty buffer for some reason... cleaning up the incomplete frame.*/
      cleanup(edp);
      goto skip;
    }
    /*
     * End Of Frame found.
     */
    if (rxptr->w2 & W2_R_FRAME_END) {
      rdp->offset = 0;
      rdp->size = rxptr->w2 & W2_T_LENGTH_MASK;
      rdp->physdesc = edp;
      return RDY_OK;
    }

    if ((edp != rxptr) && (rxptr->w2 & W2_R_FRAME_START)) {
      /* Found another start... cleaning up the incomplete frame.*/
      cleanup(edp);
      goto restart;     /* Another start buffer for some reason... */
    }

    if (++rxptr >= &rd[EMAC_RECEIVE_DESCRIPTORS])
      rxptr = rd;
    n--;
  }
  return RDY_TIMEOUT;
}

/**
 * @brief   Reads from a receive descriptor's stream.
 *
 * @param[in] rdp       pointer to a @p MACReceiveDescriptor structure
 * @param[in] buf       pointer to the buffer that will receive the read data
 * @param[in] size      number of bytes to be read
 * @return              The number of bytes read from the descriptor's
 *                      stream, this value can be less than the amount
 *                      specified in the parameter @p size if there are
 *                      no more bytes to read.
 *
 * @notapi
 */
size_t mac_lld_read_receive_descriptor(MACReceiveDescriptor *rdp,
                                         uint8_t *buf,
                                         size_t size) {
  if (size > rdp->size - rdp->offset)
    size = rdp->size - rdp->offset;
  if (size > 0) {
    uint8_t *src = (uint8_t *)(rdp->physdesc->w1 & W1_R_ADDRESS_MASK) +
                   rdp->offset;
    uint8_t *limit = &rb[EMAC_RECEIVE_DESCRIPTORS * EMAC_RECEIVE_BUFFERS_SIZE];
    if (src >= limit)
      src -= EMAC_RECEIVE_DESCRIPTORS * EMAC_RECEIVE_BUFFERS_SIZE;
    if (src + size > limit ) {
      memcpy(buf, src, (size_t)(limit - src));
      memcpy(buf + (size_t)(limit - src), rb, size - (size_t)(limit - src));
    }
    else
      memcpy(buf, src, size);
    rdp->offset += size;
  }
  return size;
}

/**
 * @brief   Releases a receive descriptor.
 * @details The descriptor and its buffer are made available for more incoming
 *          frames.
 *
 * @param[in] rdp       the pointer to the @p MACReceiveDescriptor structure
 *
 * @notapi
 */
void mac_lld_release_receive_descriptor(MACReceiveDescriptor *rdp) {
  bool_t done;
  EMACDescriptor *edp = rdp->physdesc;

  unsigned n = EMAC_RECEIVE_DESCRIPTORS;
  do {
    done = ((edp->w2 & W2_R_FRAME_END) != 0);
    chDbgAssert(edp->w1 & W1_R_OWNERSHIP,
                "mac_lld_release_receive_descriptor(), #1",
                "found not owned descriptor");
    edp->w1 &= ~(W1_R_OWNERSHIP | W2_R_FRAME_START | W2_R_FRAME_END);
    if (++edp >= &rd[EMAC_RECEIVE_DESCRIPTORS])
      edp = rd;
    n--;
  }
  while ((n > 0) && !done);
  /*
   * Make rxptr point to the descriptor where the next frame will most
   * likely appear.
   */
  rxptr = edp;
}

/**
 * @brief   Updates and returns the link status.
 *
 * @param[in] macp      pointer to the @p MACDriver object
 * @return              The link status.
 * @retval TRUE         if the link is active.
 * @retval FALSE        if the link is down.
 *
 * @notapi
 */
bool_t mac_lld_poll_link_status(MACDriver *macp) {
  uint32_t ncfgr, bmsr, bmcr, lpa;

  AT91C_BASE_EMAC->EMAC_NCR |= AT91C_EMAC_MPE;
  (void)miiGet(macp, MII_BMSR);
  bmsr = miiGet(macp, MII_BMSR);
  if (!(bmsr & BMSR_LSTATUS)) {
    AT91C_BASE_EMAC->EMAC_NCR &= ~AT91C_EMAC_MPE;
    return macp->link_up = FALSE;
  }

  ncfgr = AT91C_BASE_EMAC->EMAC_NCFGR & ~(AT91C_EMAC_SPD | AT91C_EMAC_FD);
  bmcr = miiGet(macp, MII_BMCR);
  if (bmcr & BMCR_ANENABLE) {
    lpa = miiGet(macp, MII_LPA);
    if (lpa & (LPA_100HALF | LPA_100FULL | LPA_100BASE4))
      ncfgr |= AT91C_EMAC_SPD;
    if (lpa & (LPA_10FULL | LPA_100FULL))
      ncfgr |= AT91C_EMAC_FD;
  }
  else {
    if (bmcr & BMCR_SPEED100)
      ncfgr |= AT91C_EMAC_SPD;
    if (bmcr & BMCR_FULLDPLX)
      ncfgr |= AT91C_EMAC_FD;
  }
  AT91C_BASE_EMAC->EMAC_NCFGR = ncfgr;
  AT91C_BASE_EMAC->EMAC_NCR &= ~AT91C_EMAC_MPE;
  return macp->link_up = TRUE;
}

#endif /* HAL_USE_MAC */

/** @} */