pcnet32.c

一个基于linux的TCP/IP协议栈的实现

	mii_check_media (&lp->mii_if, netif_msg_link(lp), 1);
	mod_timer (&(lp->watchdog_timer), PCNET32_WATCHDOG_TIMEOUT);
    }

    i = 0;
    while (i++ < 100)
	if (lp->a.read_csr (ioaddr, 0) & 0x0100)
	    break;
    /*
     * We used to clear the InitDone bit, 0x0100, here but Mark Stockton
     * reports that doing so triggers a bug in the '974.
     */
    lp->a.write_csr (ioaddr, 0, 0x0042);

    if (netif_msg_ifup(lp))
	printk(KERN_DEBUG "%s: pcnet32 open after %d ticks, init block %#x csr0 %4.4x.\n",
		dev->name, i, (u32) (lp->dma_addr +
		    offsetof(struct pcnet32_private, init_block)),
		lp->a.read_csr(ioaddr, 0));

    spin_unlock_irqrestore(&lp->lock, flags);

    return 0;	/* Always succeed */

err_free_ring:
    /* free any allocated skbuffs */
    for (i = 0; i < lp->rx_ring_size; i++) {
	lp->rx_ring[i].status = 0;
	if (lp->rx_skbuff[i]) {
	    pci_unmap_single(lp->pci_dev, lp->rx_dma_addr[i], PKT_BUF_SZ-2,
		    PCI_DMA_FROMDEVICE);
	    dev_kfree_skb(lp->rx_skbuff[i]);
	}
	lp->rx_skbuff[i] = NULL;
	lp->rx_dma_addr[i] = 0;
    }

    pcnet32_free_ring(dev);

    /*
     * Switch back to 16bit mode to avoid problems with dumb
     * DOS packet driver after a warm reboot
     */
    lp->a.write_bcr (ioaddr, 20, 4);

err_free_irq:
    spin_unlock_irqrestore(&lp->lock, flags);
    free_irq(dev->irq, dev);
    return rc;
}

/*
 * The LANCE has been halted for one reason or another (busmaster memory
 * arbitration error, Tx FIFO underflow, driver stopped it to reconfigure,
 * etc.).  Modern LANCE variants always reload their ring-buffer
 * configuration when restarted, so we must reinitialize our ring
 * context before restarting.  As part of this reinitialization,
 * find all packets still on the Tx ring and pretend that they had been
 * sent (in effect, drop the packets on the floor) - the higher-level
 * protocols will time out and retransmit.  It'd be better to shuffle
 * these skbs to a temp list and then actually re-Tx them after
 * restarting the chip, but I'm too lazy to do so right now.  [e-mail]
 */

static void
pcnet32_purge_tx_ring(struct net_device *dev)
{
    struct pcnet32_private *lp = dev->priv;
    int i;

    for (i = 0; i < lp->tx_ring_size; i++) {
	lp->tx_ring[i].status = 0;	/* CPU owns buffer */
	wmb();	/* Make sure adapter sees owner change */
	if (lp->tx_skbuff[i]) {
	    pci_unmap_single(lp->pci_dev, lp->tx_dma_addr[i],
		    lp->tx_skbuff[i]->len, PCI_DMA_TODEVICE);
	    dev_kfree_skb_any(lp->tx_skbuff[i]);
	}
	lp->tx_skbuff[i] = NULL;
	lp->tx_dma_addr[i] = 0;
    }
}


/* Initialize the PCNET32 Rx and Tx rings. */
static int
pcnet32_init_ring(struct net_device *dev)
{
    struct pcnet32_private *lp = dev->priv;
    int i;

    lp->tx_full = 0;
    lp->cur_rx = lp->cur_tx = 0;
    lp->dirty_rx = lp->dirty_tx = 0;

    for (i = 0; i < lp->rx_ring_size; i++) {
	struct sk_buff *rx_skbuff = lp->rx_skbuff[i];
	if (rx_skbuff == NULL) {
	    if (!(rx_skbuff = lp->rx_skbuff[i] = dev_alloc_skb (PKT_BUF_SZ))) {
		/* there is not much, we can do at this point */
		if (pcnet32_debug & NETIF_MSG_DRV)
		    printk(KERN_ERR "%s: pcnet32_init_ring dev_alloc_skb failed.\n",
			    dev->name);
		return -1;
	    }
	    skb_reserve (rx_skbuff, 2);
	}

	rmb();
	if (lp->rx_dma_addr[i] == 0)
	    lp->rx_dma_addr[i] = pci_map_single(lp->pci_dev, rx_skbuff->data,
		    PKT_BUF_SZ-2, PCI_DMA_FROMDEVICE);
	lp->rx_ring[i].base = (u32)le32_to_cpu(lp->rx_dma_addr[i]);
	lp->rx_ring[i].buf_length = le16_to_cpu(2-PKT_BUF_SZ);
	wmb();	/* Make sure owner changes after all others are visible */
	lp->rx_ring[i].status = le16_to_cpu(0x8000);
    }
    /* The Tx buffer address is filled in as needed, but we do need to clear
     * the upper ownership bit. */
    for (i = 0; i < lp->tx_ring_size; i++) {
	lp->tx_ring[i].status = 0;	/* CPU owns buffer */
	wmb();	/* Make sure adapter sees owner change */
	lp->tx_ring[i].base = 0;
	lp->tx_dma_addr[i] = 0;
    }

    lp->init_block.tlen_rlen = le16_to_cpu(lp->tx_len_bits | lp->rx_len_bits);
    for (i = 0; i < 6; i++)
	lp->init_block.phys_addr[i] = dev->dev_addr[i];
    lp->init_block.rx_ring = (u32)le32_to_cpu(lp->rx_ring_dma_addr);
    lp->init_block.tx_ring = (u32)le32_to_cpu(lp->tx_ring_dma_addr);
    wmb();	/* Make sure all changes are visible */
    return 0;
}

/* the pcnet32 has been issued a stop or reset.  Wait for the stop bit
 * then flush the pending transmit operations, re-initialize the ring,
 * and tell the chip to initialize.
 */
static void
pcnet32_restart(struct net_device *dev, unsigned int csr0_bits)
{
    struct pcnet32_private *lp = dev->priv;
    unsigned long ioaddr = dev->base_addr;
    int i;

    /* wait for stop */
    for (i=0; i<100; i++)
	if (lp->a.read_csr(ioaddr, 0) & 0x0004)
	   break;

    if (i >= 100 && netif_msg_drv(lp))
	printk(KERN_ERR "%s: pcnet32_restart timed out waiting for stop.\n",
		dev->name);

    pcnet32_purge_tx_ring(dev);
    if (pcnet32_init_ring(dev))
	return;

    /* ReInit Ring */
    lp->a.write_csr (ioaddr, 0, 1);
    i = 0;
    while (i++ < 1000)
	if (lp->a.read_csr (ioaddr, 0) & 0x0100)
	    break;

    lp->a.write_csr (ioaddr, 0, csr0_bits);
}


static void
pcnet32_tx_timeout (struct net_device *dev)
{
    struct pcnet32_private *lp = dev->priv;
    unsigned long ioaddr = dev->base_addr, flags;

    spin_lock_irqsave(&lp->lock, flags);
    /* Transmitter timeout, serious problems. */
    if (pcnet32_debug & NETIF_MSG_DRV)
	printk(KERN_ERR "%s: transmit timed out, status %4.4x, resetting.\n",
		dev->name, lp->a.read_csr(ioaddr, 0));
    lp->a.write_csr (ioaddr, 0, 0x0004);
    lp->stats.tx_errors++;
    if (netif_msg_tx_err(lp)) {
	int i;
	printk(KERN_DEBUG " Ring data dump: dirty_tx %d cur_tx %d%s cur_rx %d.",
	   lp->dirty_tx, lp->cur_tx, lp->tx_full ? " (full)" : "",
	   lp->cur_rx);
	for (i = 0 ; i < lp->rx_ring_size; i++)
	printk("%s %08x %04x %08x %04x", i & 1 ? "" : "\n ",
	       le32_to_cpu(lp->rx_ring[i].base),
	       (-le16_to_cpu(lp->rx_ring[i].buf_length)) & 0xffff,
	       le32_to_cpu(lp->rx_ring[i].msg_length),
	       le16_to_cpu(lp->rx_ring[i].status));
	for (i = 0 ; i < lp->tx_ring_size; i++)
	printk("%s %08x %04x %08x %04x", i & 1 ? "" : "\n ",
	       le32_to_cpu(lp->tx_ring[i].base),
	       (-le16_to_cpu(lp->tx_ring[i].length)) & 0xffff,
	       le32_to_cpu(lp->tx_ring[i].misc),
	       le16_to_cpu(lp->tx_ring[i].status));
	printk("\n");
    }
    pcnet32_restart(dev, 0x0042);

    dev->trans_start = jiffies;
    netif_wake_queue(dev);

    spin_unlock_irqrestore(&lp->lock, flags);
}


static int
pcnet32_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
    struct pcnet32_private *lp = dev->priv;
    unsigned long ioaddr = dev->base_addr;
    u16 status;
    int entry;
    unsigned long flags;

    spin_lock_irqsave(&lp->lock, flags);

    if (netif_msg_tx_queued(lp)) {
	printk(KERN_DEBUG "%s: pcnet32_start_xmit() called, csr0 %4.4x.\n",
	       dev->name, lp->a.read_csr(ioaddr, 0));
    }

    /* Default status -- will not enable Successful-TxDone
     * interrupt when that option is available to us.
     */
    status = 0x8300;

    /* Fill in a Tx ring entry */

    /* Mask to ring buffer boundary. */
    entry = lp->cur_tx & lp->tx_mod_mask;

    /* Caution: the write order is important here, set the status
     * with the "ownership" bits last. */

    lp->tx_ring[entry].length = le16_to_cpu(-skb->len);

    lp->tx_ring[entry].misc = 0x00000000;

    lp->tx_skbuff[entry] = skb;
    lp->tx_dma_addr[entry] = pci_map_single(lp->pci_dev, skb->data, skb->len,
	    PCI_DMA_TODEVICE);
    lp->tx_ring[entry].base = (u32)le32_to_cpu(lp->tx_dma_addr[entry]);
    wmb(); /* Make sure owner changes after all others are visible */
    lp->tx_ring[entry].status = le16_to_cpu(status);

    lp->cur_tx++;
    lp->stats.tx_bytes += skb->len;

    /* Trigger an immediate send poll. */
    lp->a.write_csr (ioaddr, 0, 0x0048);

    dev->trans_start = jiffies;

    if (lp->tx_ring[(entry+1) & lp->tx_mod_mask].base != 0) {
	lp->tx_full = 1;
	netif_stop_queue(dev);
    }
    spin_unlock_irqrestore(&lp->lock, flags);
    return 0;
}

/* The PCNET32 interrupt handler. */
static irqreturn_t
pcnet32_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
    struct net_device *dev = dev_id;
    struct pcnet32_private *lp;
    unsigned long ioaddr;
    u16 csr0,rap;
    int boguscnt =  max_interrupt_work;
    int must_restart;

    if (!dev) {
	if (pcnet32_debug & NETIF_MSG_INTR)
	    printk (KERN_DEBUG "%s(): irq %d for unknown device\n",
		__FUNCTION__, irq);
	return IRQ_NONE;
    }

    ioaddr = dev->base_addr;
    lp = dev->priv;

    spin_lock(&lp->lock);

    rap = lp->a.read_rap(ioaddr);
    while ((csr0 = lp->a.read_csr (ioaddr, 0)) & 0x8f00 && --boguscnt >= 0) {
	if (csr0 == 0xffff) {
	    break;			/* PCMCIA remove happened */
	}
	/* Acknowledge all of the current interrupt sources ASAP. */
	lp->a.write_csr (ioaddr, 0, csr0 & ~0x004f);

	must_restart = 0;

	if (netif_msg_intr(lp))
	    printk(KERN_DEBUG "%s: interrupt  csr0=%#2.2x new csr=%#2.2x.\n",
		   dev->name, csr0, lp->a.read_csr (ioaddr, 0));

	if (csr0 & 0x0400)		/* Rx interrupt */
	    pcnet32_rx(dev);

	if (csr0 & 0x0200) {		/* Tx-done interrupt */
	    unsigned int dirty_tx = lp->dirty_tx;
	    int delta;

	    while (dirty_tx != lp->cur_tx) {
		int entry = dirty_tx & lp->tx_mod_mask;
		int status = (short)le16_to_cpu(lp->tx_ring[entry].status);

		if (status < 0)
		    break;		/* It still hasn't been Txed */

		lp->tx_ring[entry].base = 0;

		if (status & 0x4000) {
		    /* There was an major error, log it. */
		    int err_status = le32_to_cpu(lp->tx_ring[entry].misc);
		    lp->stats.tx_errors++;
		    if (netif_msg_tx_err(lp))
			printk(KERN_ERR "%s: Tx error status=%04x err_status=%08x\n",
				dev->name, status, err_status);
		    if (err_status & 0x04000000) lp->stats.tx_aborted_errors++;
		    if (err_status & 0x08000000) lp->stats.tx_carrier_errors++;
		    if (err_status & 0x10000000) lp->stats.tx_window_errors++;
#ifndef DO_DXSUFLO
		    if (err_status & 0x40000000) {
			lp->stats.tx_fifo_errors++;
			/* Ackk!  On FIFO errors the Tx unit is turned off! */
			/* Remove this verbosity later! */
			if (netif_msg_tx_err(lp))
			    printk(KERN_ERR "%s: Tx FIFO error! CSR0=%4.4x\n",
				    dev->name, csr0);
			must_restart = 1;
		    }
#else
		    if (err_status & 0x40000000) {
			lp->stats.tx_fifo_errors++;
			if (! lp->dxsuflo) {  /* If controller doesn't recover ... */
			    /* Ackk!  On FIFO errors the Tx unit is turned off! */
			    /* Remove this verbosity later! */
			    if (netif_msg_tx_err(lp))
				printk(KERN_ERR "%s: Tx FIFO error! CSR0=%4.4x\n",
					dev->name, csr0);
			    must_restart = 1;
			}
		    }
#endif
		} else {
		    if (status & 0x1800)
			lp->stats.collisions++;
		    lp->stats.tx_packets++;
		}

		/* We must free the original skb */
		if (lp->tx_skbuff[entry]) {
		    pci_unmap_single(lp->pci_dev, lp->tx_dma_addr[entry],
			lp->tx_skbuff[entry]->len, PCI_DMA_TODEVICE);
		    dev_kfree_skb_irq(lp->tx_skbuff[entry]);
		    lp->tx_skbuff[entry] = NULL;
		    lp->tx_dma_addr[entry] = 0;
		}
		dirty_tx++;
	    }

	    delta = (lp->cur_tx - dirty_tx) & (lp->tx_mod_mask + lp->tx_ring_size);
	    if (delta > lp->tx_ring_size) {
		if (netif_msg_drv(lp))
		    printk(KERN_ERR "%s: out-of-sync dirty pointer, %d vs. %d, full=%d.\n",
			    dev->name, dirty_tx, lp->cur_tx, lp->tx_full);
		dirty_tx += lp->tx_ring_size;
		delta -= lp->tx_ring_size;
	    }

	    if (lp->tx_full &&
		netif_queue_stopped(dev) &&
		delta < lp->tx_ring_size - 2) {
		/* The ring is no longer full, clear tbusy. */
		lp->tx_full = 0;
		netif_wake_queue (dev);
	    }
	    lp->dirty_tx = dirty_tx;
	}

	/* Log misc errors. */
	if (csr0 & 0x4000) lp->stats.tx_errors++; /* Tx babble. */
	if (csr0 & 0x1000) {
	    /*
	     * this happens when our receive ring is full. This shouldn't
	     * be a problem as we will see normal rx interrupts for the frames
	     * in the receive ring. But there are some PCI chipsets (I can
	     * reproduce this on SP3G with Intel saturn chipset) which have
	     * sometimes problems and will fill up the receive ring with
	     * error descriptors. In this situation we don't get a rx
	     * interrupt, but a missed frame interrupt sooner or later.
	     * So we try to clean up our receive ring here.
	     */
	    pcnet32_rx(dev);
	    lp->stats.rx_errors++; /* Missed a Rx frame. */
	}
	if (csr0 & 0x0800) {
	    if (netif_msg_drv(lp))
		printk(KERN_ERR "%s: Bus master arbitration failure, status %4.4x.\n",
			dev->name, csr0);
	    /* unlike for the lance, there is no restart needed */
	}

	if (must_restart) {
	    /* reset the chip to clear the error condition, then restart */
	    lp->a.reset(ioaddr);