if_8139.c

eCos操作系统源码

  rltk8139_info = (Rltk8139_t *)(sc->driver_private);

#ifdef DEBUG_RLTK8139_DRIVER
  diag_printf("rltk8139_send(%s, %08x, %d, %d, %08lx)\n",
              sc->dev_name, sg_list, sg_len, total_len, key);
#endif

  CYG_ASSERT(total_len <= TX_BUF_SIZE, "packet too long");

  /*
   * Get the next free descriptor to send. We lock out all interrupts
   * and scheduling because we really, really do not want to be interrupted
   * at this point.
   *
   * IMPORTANT NOTE: the RealTek data sheet does not really make this clear,
   * but when they talk about a 'ring' of transmit descriptors, they
   * _really_ mean it, i.e. you _must_ use descriptor #1 after descriptor
   * #0 even if transmission of descriptor #0 has already completed.
   */
  cyg_drv_isr_lock();

  /*
   * Sanity check to see if '_send' was called even though there is no free
   * descriptor. This is probably unnecessary.
   */
  if (rltk8139_info->tx_num_free_desc == 0) {
      cyg_drv_isr_unlock();
#ifdef DEBUG_RLTK8139_DRIVER
    diag_printf("rltk8139_send(%s): no free descriptor available\n",
                sc->dev_name);
#endif
    return;
  }

  /*
   * Get the free descriptor and advance the descriptor counter modulo
   * TX_NUM_DESC. We assume that TX_NUM_DESC will always be a power of 2.
   */
  desc = rltk8139_info->tx_free_desc;
  rltk8139_info->tx_free_desc = (rltk8139_info->tx_free_desc + 1)
    & (NUM_TX_DESC - 1);

  /* Decrement the number of free descriptors */
  rltk8139_info->tx_num_free_desc -= 1;

  /* Reenable interrupts at this point */
  cyg_drv_isr_unlock();

  /*
   * Determine the buffer memory to use and tell the hardware about it.
   * Since we use fixed buffer addresses, we do not need to set up TSADx.
   * Memorize the key so we can call the tx_done callback correctly.
   *
   * While it would be possible to set TSADx to the packet directly if
   * it is stored in a linear memory area with 32 bit alignment, it seems
   * this happens so seldomly that it's simply not worth the extra
   * runtime check.
   */
  tx_buffer = CYGARC_UNCACHED_ADDRESS(rltk8139_info->tx_buffer
                                      + TX_BUF_SIZE * desc);
  rltk8139_info->tx_desc_key[desc] = key;

  /*
   * Copy the data to the designated position. Note that unlike the eCos
   * Intel 82559 driver, we simply assume that all the scatter/gather list
   * elements' lengths will add up to total_len exactly, and don't check
   * to make sure.
   */
  for (last_sg = &sg_list[sg_len]; sg_list < last_sg; ++sg_list) {
    memcpy(tx_buffer, (void *)(sg_list->buf), sg_list->len);
    tx_buffer += sg_list->len;
  }

  /*
   * Make sure the packet has the minimum ethernet packet size, padding
   * with zeros if necessary.
   */
  if (total_len < MIN_ETH_FRAME_SIZE) {
    memset(tx_buffer, 0, MIN_ETH_FRAME_SIZE - total_len);
    total_len = MIN_ETH_FRAME_SIZE;
  }

  /*
   * Flush the data cache here if necessary. This ensures the 8139 can
   * read the correct data from the transmit buffer.
   */
#ifdef CYGPKG_DEVS_ETH_RLTK_8139_SOFTWARE_CACHE_COHERENCY
  HAL_DCACHE_FLUSH(rltk8139_info->tx_buffer + TX_BUF_SIZE * desc, total_len);
#endif

  /*
   * Now setup the correct transmit descriptor to actually send the data.
   * The early TX threshold is incremented by the driver until we reach a
   * size that prevents transmit underruns. (An earlier attempt to calculate
   * this parameter from the packet size didn't work).
   */
  OUTL((rltk8139_info->tx_threshold << ERTXTH_SHIFT) | (total_len & SIZE),
       rltk8139_info->base_address + TSD0 + (desc<<2));
}


/*
 * This routine actually retrieves data from the receive ring by
 * copying it into the specified scatter/gather buffers. Again,
 * we assume the scatter/gather list is OK and don't check against
 * total length.
 */
static void
rltk8139_recv(struct eth_drv_sc *sc, struct eth_drv_sg *sg_list,
              int sg_len)
{
  Rltk8139_t *rltk8139_info;
  struct eth_drv_sg *last_sg;
  cyg_uint8 *rx_buffer;


  rltk8139_info = (Rltk8139_t *)(sc->driver_private);
  rx_buffer = rltk8139_info->rx_current;

  /*
   * Invalidate the cache line(s) mapped to the receive buffer
   * if necessary.
   */
#ifdef CYGPKG_DEVS_ETH_RLTK_8139_SOFTWARE_CACHE_COHERENCY
  HAL_DCACHE_INVALIDATE(rx_buffer, rltk8139_info->rx_size);
#endif

  for (last_sg = &sg_list[sg_len]; sg_list < last_sg; ++sg_list) {
    memcpy((void *)(sg_list->buf), rx_buffer, sg_list->len);
    rx_buffer += sg_list->len;
  }
}


/*
 * This function does all the heavy lifting associated with interrupts.
 */
static void
rltk8139_deliver(struct eth_drv_sc *sc)
{
  Rltk8139_t *rltk8139_info;
  cyg_uint16 status, pci_status;
  cyg_uint32 tsd;
  int desc;


  rltk8139_info = (Rltk8139_t *)(sc->driver_private);

  /*
   * The RealTek data sheet claims that reading the ISR will clear
   * it. This is incorrect; to clear a bit in the ISR, a '1' must be
   * written to the ISR instead. We immediately clear the interrupt
   * bits at this point.
   */
  status = INW(rltk8139_info->base_address + ISR);
  OUTW(status, rltk8139_info->base_address + ISR);

#ifdef DEBUG_RLTK8139_DRIVER
  diag_printf("rltk8139_deliver(%s): %04x\n", sc->dev_name, status);
#endif

  /*
   * Check for a PCI error. This seems like a very serious error to
   * me, so we will reset the chip and hope for the best.
   */
  if (status & IR_SERR) {
    cyg_pci_read_config_uint16(rltk8139_info->pci_device_id,
                               CYG_PCI_CFG_STATUS, &pci_status);
    cyg_pci_write_config_uint16(rltk8139_info->pci_device_id,
                                CYG_PCI_CFG_STATUS, pci_status);
#ifdef DEBUG_RLTK8139_DRIVER
    diag_printf("rltk8139_deliver(%s): PCI error %04x\n",
                sc->dev_name, pci_status);
#endif

    rltk8139_reset(sc);
    return;
  }

  /* Check for transmission complete (with errors or not) */
  if ((status & IR_TER) || (status & IR_TOK)) {
    /*
     * Figure out which descriptors' status must be checked. We lock out
     * interrupts while manipulating the descriptor list because we do not
     * want to be interrupted at this point.
     */
    while (1) {
      cyg_drv_isr_lock();

      /* Check if all descriptors are ready, in which case we are done. */
      if (rltk8139_info->tx_num_free_desc >= NUM_TX_DESC) {
          cyg_drv_isr_unlock();
        break;
      }

      desc = (rltk8139_info->tx_free_desc
              - (NUM_TX_DESC - rltk8139_info->tx_num_free_desc))
        & (NUM_TX_DESC - 1);
      cyg_drv_isr_unlock();

      /* Get the current status of the descriptor */
      tsd = INL(rltk8139_info->base_address + TSD0 + (desc<<2));

      /*
       * If a transmit FIFO underrun occurred, increment the threshold
       * value.
       */
      if ((tsd & TUN) && (rltk8139_info->tx_threshold < 64))
        rltk8139_info->tx_threshold += 1;

      /*
       * Check if a transmission completed OK. RealTek's data sheet implies
       * that a successful transmission that experiences underrun will only
       * set TUN. This is not true; TOK is set for all successful
       * transmissions.
       */
      if (tsd & TOK) {
        (sc->funs->eth_drv->tx_done)(sc, rltk8139_info->tx_desc_key[desc], 0);
      }
      else if (tsd & TABT) {
        /*
         * Set the CLRABT bit in TCR. Since I haven't encountered any
         * transmission aborts so far, I don't really know if this code
         * will work or not.
         */
        OUTL(INL(rltk8139_info->base_address + TCR) & CLRABT,
             rltk8139_info->base_address + TCR);
        (sc->funs->eth_drv->tx_done)(sc, rltk8139_info->tx_desc_key[desc], -1);
      }
      else {
        /*
         * This descriptor is not ready. Since the descriptors are used
         * in a ring, this means that no more descriptors are ready.
         */
        break;
      }

      /*
       * Clear the saved key value. This is not really necessary, since
       * the key value is never used to determine if a descriptor is
       * valid or not. However, clearing it is a tidier IMO.
       */
      rltk8139_info->tx_desc_key[desc] = 0;

      /*
       * Increment the free descriptor count and go through the loop again
       * to see if more descriptors are ready.
       */
      cyg_drv_isr_lock();
      rltk8139_info->tx_num_free_desc += 1;
      cyg_drv_isr_unlock();
    }
  }

  if (status & IR_ROK) {
    /*
     * Received a frame. Note that '_deliver' does not actually copy any
     * data; it just determines how many bytes are available and tells
     * the generic ethernet driver about it, which then calls into
     * the '_recv' function to copy the data.
     */
    cyg_uint16 rx_pos;
    cyg_uint32 header, length;

    /*
     * CAPR contains the index into the receive buffer. It is controlled
     * completely in software. For some reason, CAPR points 16 bytes
     * before the actual start of the packet.
     */
    rx_pos = (INW(rltk8139_info->base_address + CAPR) + 16) % RX_BUF_LEN;

    /*
     * Loop until the rx buffer is empty. I have no idea how the 8139
     * determines if the buffer still contains a packet; it may check
     * that CAPR points 16 bytes before CBR.
     */
    while (!(INB(rltk8139_info->base_address + CR) & BUFE)) {
      /*
       * Invalidate the data cache for the cache line containing the header
       * if necessary.
       */
#ifdef CYGPKG_DEVS_ETH_RLTK_8139_SOFTWARE_CACHE_COHERENCY
      HAL_DCACHE_INVALIDATE(&rltk8139_info->rx_ring[rx_pos],
                            sizeof(cyg_uint32));
#endif

      /*
       * The 8139 prepends each packet with a 32 bit packet header that
       * contains a 16 bit length and 16 bit status field, in little-endian
       * byte order.
       */
      header = HAL_LE32TOC(*((volatile cyg_uint32 *)CYGARC_UNCACHED_ADDRESS(&rltk8139_info->rx_ring[rx_pos])));

      /*
       * If the 8139 is still copying data for this packet into the
       * receive ring, it will set packet length to 0xfff0. This shouldn't
       * ever happen because we do not use early receive.
       */
      if ((header >> 16) == 0xFFF0)
        break;

      /*
       * Since the 8139 appends the ethernet CRC to every packet, we
       * must subtract 4 from the length to get the true packet length.
       */
      length = (header >> 16) - 4;

      /*
       * Check if the packet was received correctly. The OpenBSD driver
       * resets the chip if this is not the case; we attempt to salvage
       * following packets by doing nothing.
       */
      if (!(header & HDR_ROK)) {
      }
      else {
        /*
         * Packet was received OK. Determine from where to start copying
         * bytes. This is saved in the driver private area so rlt8139_recv
         * doesn't have to redetermine this information. Then, inform
         * the generic ethernet driver about the packet.
         */
        rltk8139_info->rx_current = CYGARC_UNCACHED_ADDRESS(rltk8139_info->rx_ring + rx_pos + 4);
        rltk8139_info->rx_size = length;

        /* Tell eCos about the packet */
        (sc->funs->eth_drv->recv)(sc, length);
      }

      /*
       * Update CAPR. CAPR must be aligned to a 32 bit boundary, and should
       * point 16 bytes before it's actual position.
       */
      rx_pos = ((rx_pos + length + 8 + 3) & ~3) % RX_BUF_LEN;
      OUTW((rx_pos - 16) % RX_BUF_LEN, rltk8139_info->base_address + CAPR);
    }
  }

  if (status & IR_RXOVW) {
    /*
     * In case of a receive buffer overflow, the RealTek data sheet claims we
     * should update CAPR and then write a '1'爐o ROK in ISR. However, none of
     * the other 8139 drivers I have looked at do this, so we will just reset
     * the chip instead.
     */
#ifdef DEBUG_RLTK8139_DRIVER
    diag_printf("rltk8139_deliver(%s): receive buffer overflow\n",
                sc->dev_name);
#endif
    rltk8139_reset(sc);
    return;
  }

  if (status & IR_FOVW) {
    /*
     * Rx FIFO overflow. According to RealTek's data sheet, this is cleared
     * by writing a '1' to RXOVW. Again, none of the 8139 drivers I have
     * seen actually do this, so we reset the chip instead.
     */
#ifdef DEBUG_RLTK8139_DRIVER
    diag_printf("rltk8139_deliver(%s): receive FIFO overflow\n",
                sc->dev_name);
#endif
    rltk8139_reset(sc);
    return;
  }

#ifndef CYGPKG_IO_ETH_DRIVERS_STAND_ALONE
  /* Finally, reenable interrupts */
#ifdef CYGPKG_DEVS_ETH_RLTK_8139_MASK_INTERRUPTS_IN_8139
  OUTW(RLTK8139_IRQ, rltk8139_info->base_address + IMR);
#else
  cyg_interrupt_unmask(rltk8139_info->vector);
#endif
#endif
}


/*
 * '_poll' does the same thing as '_deliver'. It is called periodically when
 * the ethernet driver is operated in non-interrupt mode, for instance by
 * RedBoot.
 */
static void
rltk8139_poll(struct eth_drv_sc *sc)
{
  Rltk8139_t *rltk8139_info;
  cyg_uint16 isr;


#ifdef DEBUG_RLTK8139_DRIVER
  diag_printf("rltk8139_poll(%s)\n", sc->dev_name);
#endif

  rltk8139_info = (Rltk8139_t *)(sc->driver_private);

  /*
   * Get the current interrupt status. If anything changed, call
   * _deliver.
   */
  if ((isr = INW(rltk8139_info->base_address + ISR)))
    rltk8139_deliver(sc);
}


/*
 * Return the interrupt vector used by this device.
 */
static int
rltk8139_int_vector(struct eth_drv_sc *sc)
{
  return ((Rltk8139_t *)(sc->driver_private))->vector;
}


/*
 * Quick and dirty register dump. This is somewhat dangerous, since
 * we read the register space 32 bits at a time, regardless of actual
 * register sizes.
 */
#ifdef DEBUG_RLTK8139_DRIVER
void
rltk8139_print_state(struct eth_drv_sc *sc) {
  int i;
  Rltk8139_t *rltk8139_info;


  rltk8139_info = (Rltk8139_t *)(sc->driver_private);

  for (i = IDR0; i < FFER; i += 16) {
    diag_printf("8139 reg address 0x%02x = 0x%08x", i,
                INL(rltk8139_info->base_address + i));
    diag_printf(" 0x%08x", INL(rltk8139_info->base_address + i + 4));
    diag_printf(" 0x%08x", INL(rltk8139_info->base_address + i + 8));
    diag_printf(" 0x%08x\n", INL(rltk8139_info->base_address + i + 12));
  }
}
#endif