lance.c

LINUX1.0内核源代码,学习LINUX编程的一定要看。

    if (lance_debug > 2)
	printk("%s: LANCE open after %d ticks, init block %#x csr0 %4.4x.\n",
	       dev->name, i, (int) &lp->init_block, inw(ioaddr+LANCE_DATA));

    return 0;			/* Always succeed */
}

/* Initialize the LANCE Rx and Tx rings. */
static void
lance_init_ring(struct device *dev)
{
    struct lance_private *lp = (struct lance_private *)dev->priv;
    int i;

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

    for (i = 0; i < RX_RING_SIZE; i++) {
	lp->rx_ring[i].base = (lp->rx_buffs + i*PKT_BUF_SZ) | 0x80000000;
	lp->rx_ring[i].buf_length = -PKT_BUF_SZ;
    }
    /* The Tx buffer address is filled in as needed, but we do need to clear
       the upper ownership bit. */
    for (i = 0; i < TX_RING_SIZE; i++) {
	lp->tx_ring[i].base = 0;
    }

    lp->init_block.mode = 0x0000;
    for (i = 0; i < 6; i++)
	lp->init_block.phys_addr[i] = dev->dev_addr[i];
    lp->init_block.filter[0] = 0x00000000;
    lp->init_block.filter[1] = 0x00000000;
    lp->init_block.rx_ring = (int)lp->rx_ring | RX_RING_LEN_BITS;
    lp->init_block.tx_ring = (int)lp->tx_ring | TX_RING_LEN_BITS;
}

static int
lance_start_xmit(struct sk_buff *skb, struct device *dev)
{
    struct lance_private *lp = (struct lance_private *)dev->priv;
    int ioaddr = dev->base_addr;
    int entry;

    /* Transmitter timeout, serious problems. */
    if (dev->tbusy) {
	int tickssofar = jiffies - dev->trans_start;
	if (tickssofar < 10)
	    return 1;
	outw(0, ioaddr+LANCE_ADDR);
	printk("%s: transmit timed out, status %4.4x, resetting.\n",
	       dev->name, inw(ioaddr+LANCE_DATA));
	outw(0x0001, ioaddr+LANCE_DATA);
	lp->stats.tx_errors++;
#ifndef final_version
	{
	    int i;
	    printk(" Ring data dump: dirty_tx %d cur_tx %d cur_rx %d.",
		   lp->dirty_tx, lp->cur_tx, lp->cur_rx);
	    for (i = 0 ; i < RX_RING_SIZE; i++)
		printk("%s %08x %04x %04x", i & 0x3 ? "" : "\n ",
		       lp->rx_ring[i].base, -lp->rx_ring[i].buf_length,
		       lp->rx_ring[i].msg_length);
	    for (i = 0 ; i < TX_RING_SIZE; i++)
		printk(" %s%08x %04x %04x", i & 0x3 ? "" : "\n ",
		       lp->tx_ring[i].base, -lp->tx_ring[i].length,
		       lp->tx_ring[i].misc);
	    printk("\n");
	}
#endif
	lance_init_ring(dev);
	outw(0x0043, ioaddr+LANCE_DATA);

	dev->tbusy=0;
	dev->trans_start = jiffies;

	return 0;
    }

    if (skb == NULL) {
	dev_tint(dev);
	return 0;
    }

    /* Fill in the ethernet header. */
    if (!skb->arp  &&  dev->rebuild_header(skb->data, dev)) {
	skb->dev = dev;
	arp_queue (skb);
	return 0;
    }
    skb->arp=1;

    if (skb->len <= 0)
	return 0;

    if (lance_debug > 3) {
	outw(0x0000, ioaddr+LANCE_ADDR);
	printk("%s: lance_start_xmit() called, csr0 %4.4x.\n", dev->name,
	       inw(ioaddr+LANCE_DATA));
	outw(0x0000, ioaddr+LANCE_DATA);
    }

    /* Block a timer-based transmit from overlapping.  This could better be
       done with atomic_swap(1, dev->tbusy), but set_bit() works as well. */
    if (set_bit(0, (void*)&dev->tbusy) != 0)
	printk("%s: Transmitter access conflict.\n", dev->name);

    /* Fill in a Tx ring entry */

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

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

    /* The old LANCE chips doesn't automatically pad buffers to min. size. */
    if (lp->old_lance) {
	lp->tx_ring[entry].length =
	    -(ETH_ZLEN < skb->len ? skb->len : ETH_ZLEN);
    } else
	lp->tx_ring[entry].length = -skb->len;

    lp->tx_ring[entry].misc = 0x0000;

    /* If any part of this buffer is >16M we must copy it to a low-memory
       buffer. */
    if ((int)(skb->data) + skb->len > 0x01000000) {
	if (lance_debug > 5)
	    printk("%s: bouncing a high-memory packet (%#x).\n",
		   dev->name, (int)(skb->data));
	memcpy(&lp->tx_bounce_buffs[entry], skb->data, skb->len);
	lp->tx_ring[entry].base =
	    (int)(lp->tx_bounce_buffs + entry) | 0x83000000;
	if (skb->free)
	    kfree_skb (skb, FREE_WRITE);
    } else {
    	/* We can't free the packet yet, so we inform the memory management
	   code that we are still using it. */
    	if(skb->free==0)
    		skb_kept_by_device(skb);
	lp->tx_ring[entry].base = (int)(skb->data) | 0x83000000;
    }
    lp->cur_tx++;

    /* Trigger an immediate send poll. */
    outw(0x0000, ioaddr+LANCE_ADDR);
    outw(0x0048, ioaddr+LANCE_DATA);

    dev->trans_start = jiffies;

    if (lp->tx_ring[(entry+1) & TX_RING_MOD_MASK].base == 0)
	dev->tbusy=0;

    return 0;
}

/* The LANCE interrupt handler. */
static void
lance_interrupt(int reg_ptr)
{
    int irq = -(((struct pt_regs *)reg_ptr)->orig_eax+2);
    struct device *dev = (struct device *)(irq2dev_map[irq]);
    struct lance_private *lp;
    int csr0, ioaddr;

    if (dev == NULL) {
	printk ("lance_interrupt(): irq %d for unknown device.\n", irq);
	return;
    }

    ioaddr = dev->base_addr;
    lp = (struct lance_private *)dev->priv;
    if (dev->interrupt)
	printk("%s: Re-entering the interrupt handler.\n", dev->name);

    dev->interrupt = 1;

    outw(0x00, dev->base_addr + LANCE_ADDR);
    csr0 = inw(dev->base_addr + LANCE_DATA);

    /* Acknowledge all of the current interrupt sources ASAP. */
    outw(csr0 & ~0x004f, dev->base_addr + LANCE_DATA);

    if (lance_debug > 5)
	printk("%s: interrupt  csr0=%#2.2x new csr=%#2.2x.\n",
	       dev->name, csr0, inw(dev->base_addr + LANCE_DATA));

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

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

	while (dirty_tx < lp->cur_tx) {
	    int entry = dirty_tx & TX_RING_MOD_MASK;
	    int status = lp->tx_ring[entry].base;
	    void *databuff;
	    
	    if (status < 0)
		break;		/* It still hasn't been Txed */

	    lp->tx_ring[entry].base = 0;
	    databuff = (void*)(status & 0x00ffffff);

	    if (status & 0x40000000) { /* There was an major error, log it. */
		int err_status = lp->tx_ring[entry].misc;
		lp->stats.tx_errors++;
		if (err_status & 0x0400) lp->stats.tx_aborted_errors++;
		if (err_status & 0x0800) lp->stats.tx_carrier_errors++;
		if (err_status & 0x1000) lp->stats.tx_window_errors++;
		if (err_status & 0x4000) lp->stats.tx_fifo_errors++;
		/* Perhaps we should re-init() after the FIFO error. */
	    } else {
		if (status & 0x18000000)
		    lp->stats.collisions++;
		lp->stats.tx_packets++;
	    }

	    /* We don't free the skb if it's a data-only copy in the bounce
	       buffer.  The address checks here are sorted -- the first test
	       should always work.  */
	    if (databuff >= (void*)(&lp->tx_bounce_buffs[TX_RING_SIZE])
		|| databuff < (void*)(lp->tx_bounce_buffs)) {
		struct sk_buff *skb = ((struct sk_buff *)databuff) - 1;
		if (skb->free)
		    kfree_skb(skb, FREE_WRITE);
		else
		    skb_device_release(skb,FREE_WRITE);
		/* Warning: skb may well vanish at the point you call
		   device_release! */
	    }
	    dirty_tx++;
	}

#ifndef final_version
	if (lp->cur_tx - dirty_tx >= TX_RING_SIZE) {
	    printk("out-of-sync dirty pointer, %d vs. %d.\n",
		   dirty_tx, lp->cur_tx);
	    dirty_tx += TX_RING_SIZE;
	}
#endif

	if (dev->tbusy  &&  dirty_tx > lp->cur_tx - TX_RING_SIZE + 2) {
	    /* The ring is no longer full, clear tbusy. */
	    dev->tbusy = 0;
	    mark_bh(INET_BH);
	}

	lp->dirty_tx = dirty_tx;
    }

    if (csr0 & 0x8000) {
	if (csr0 & 0x4000) lp->stats.tx_errors++;
	if (csr0 & 0x1000) lp->stats.rx_errors++;
    }

    /* Clear the interrupts we've handled. */
    outw(0x0000, dev->base_addr + LANCE_ADDR);
    outw(0x7f40, dev->base_addr + LANCE_DATA);

    if (lance_debug > 4)
	printk("%s: exiting interrupt, csr%d=%#4.4x.\n",
	       dev->name, inw(ioaddr + LANCE_ADDR),
	       inw(dev->base_addr + LANCE_DATA));

    dev->interrupt = 0;
    return;
}

static int
lance_rx(struct device *dev)
{
    struct lance_private *lp = (struct lance_private *)dev->priv;
    int entry = lp->cur_rx & RX_RING_MOD_MASK;
	
    /* If we own the next entry, it's a new packet. Send it up. */
    while (lp->rx_ring[entry].base >= 0) {
	int status = lp->rx_ring[entry].base >> 24;

	if (status != 0x03) {		/* There was an error. */
	    /* There is an tricky error noted by John Murphy,
	       <[e-mail]> to Russ Nelson: Even with full-sized
	       buffers it's possible for a jabber packet to use two
	       buffers, with only the last correctly noting the error. */
	    if (status & 0x01)	/* Only count a general error at the */
		lp->stats.rx_errors++; /* end of a packet.*/
	    if (status & 0x20) lp->stats.rx_frame_errors++;
	    if (status & 0x10) lp->stats.rx_over_errors++;
	    if (status & 0x08) lp->stats.rx_crc_errors++;
	    if (status & 0x04) lp->stats.rx_fifo_errors++;
	} else {
	    /* Malloc up new buffer, compatible with net-2e. */
	    short pkt_len = lp->rx_ring[entry].msg_length;
	    int sksize = sizeof(struct sk_buff) + pkt_len;
	    struct sk_buff *skb;

	    skb = alloc_skb(sksize, GFP_ATOMIC);
	    if (skb == NULL) {
		printk("%s: Memory squeeze, deferring packet.\n", dev->name);
		lp->stats.rx_dropped++;	/* Really, deferred. */
		break;
	    }
	    skb->mem_len = sksize;
	    skb->mem_addr = skb;
	    skb->len = pkt_len;
	    skb->dev = dev;
	    memcpy(skb->data,
		   (unsigned char *)(lp->rx_ring[entry].base & 0x00ffffff),
		   pkt_len);
#ifdef HAVE_NETIF_RX
	    netif_rx(skb);
#else
	    skb->lock = 0;
	    if (dev_rint((unsigned char*)skb, pkt_len, IN_SKBUFF, dev) != 0) {
		kfree_skbmem(skb, sksize);
		lp->stats.rx_dropped++;
		break;
	    }
#endif
	    lp->stats.rx_packets++;
	}

	lp->rx_ring[entry].base |= 0x80000000;
	entry = (++lp->cur_rx) & RX_RING_MOD_MASK;
    }

    /* We should check that at least two ring entries are free.  If not,
       we should free one and mark stats->rx_dropped++. */

    return 0;
}

static int
lance_close(struct device *dev)
{
    int ioaddr = dev->base_addr;
    struct lance_private *lp = (struct lance_private *)dev->priv;

    dev->start = 0;
    dev->tbusy = 1;

    outw(112, ioaddr+LANCE_ADDR);
    lp->stats.rx_missed_errors = inw(ioaddr+LANCE_DATA);

    outw(0, ioaddr+LANCE_ADDR);

    if (lance_debug > 1)
	printk("%s: Shutting down ethercard, status was %2.2x.\n",
	       dev->name, inw(ioaddr+LANCE_DATA));

    /* We stop the LANCE here -- it occasionally polls
       memory if we don't. */
    outw(0x0004, ioaddr+LANCE_DATA);

    disable_dma(dev->dma);

    free_irq(dev->irq);
    free_dma(dev->dma);

    irq2dev_map[dev->irq] = 0;

    return 0;
}

static struct enet_statistics *
lance_get_stats(struct device *dev)
{
    struct lance_private *lp = (struct lance_private *)dev->priv;
    short ioaddr = dev->base_addr;
    short saved_addr;

    cli();
    saved_addr = inw(ioaddr+LANCE_ADDR);
    outw(112, ioaddr+LANCE_ADDR);
    lp->stats.rx_missed_errors = inw(ioaddr+LANCE_DATA);
    outw(saved_addr, ioaddr+LANCE_ADDR);
    sti();

    return &lp->stats;
}

#ifdef HAVE_MULTICAST
/* Set or clear the multicast filter for this adaptor.
   num_addrs == -1	Promiscuous mode, receive all packets
   num_addrs == 0	Normal mode, clear multicast list
   num_addrs > 0	Multicast mode, receive normal and MC packets, and do
   			best-effort filtering.
 */
static void
set_multicast_list(struct device *dev, int num_addrs, void *addrs)
{
    short ioaddr = dev->base_addr;

    /* We take the simple way out and always enable promiscuous mode. */
    outw(0, ioaddr+LANCE_ADDR);
    outw(0x0004, ioaddr+LANCE_DATA); /* Temporarily stop the lance.  */

    outw(15, ioaddr+LANCE_ADDR);
    if (num_addrs >= 0) {
	short multicast_table[4];
	int i;
	/* We don't use the multicast table, but rely on upper-layer filtering. */
	memset(multicast_table, (num_addrs == 0) ? 0 : -1, sizeof(multicast_table));
	for (i = 0; i < 4; i++) {
	    outw(8 + i, ioaddr+LANCE_ADDR);
	    outw(multicast_table[i], ioaddr+LANCE_DATA);
	}
	outw(0x0000, ioaddr+LANCE_DATA); /* Unset promiscuous mode */
    } else {
	outw(0x8000, ioaddr+LANCE_DATA); /* Set promiscuous mode */
    }

    outw(0, ioaddr+LANCE_ADDR);
    outw(0x0142, ioaddr+LANCE_DATA); /* Resume normal operation. */
}
#endif

#ifdef HAVE_DEVLIST
static unsigned int lance_portlist[] = {0x300, 0x320, 0x340, 0x360, 0};
struct netdev_entry lance_drv =
{"lance", lance_probe1, LANCE_TOTAL_SIZE, lance_portlist};
#endif

/*
 * Local variables:
 *  compile-command: "gcc -D__KERNEL__ -I/usr/src/linux/net/inet -Wall -Wstrict-prototypes -O6 -m486 -c lance.c"
 * End:
 */