natsemi.c

Linux下各种网卡的驱动程序

		np->full_duplex = duplex;
		if (np->msg_level & NETIF_MSG_LINK)
			printk(KERN_INFO "%s: Setting %s-duplex based on negotiated link"
				   " capability.\n", dev->name,
				   duplex ? "full" : "half");
		if (duplex) {
			np->rx_config |= 0x10000000;
			np->tx_config |= 0xC0000000;
		} else {
			np->rx_config &= ~0x10000000;
			np->tx_config &= ~0xC0000000;
		}
		writel(np->tx_config, ioaddr + TxConfig);
		writel(np->rx_config, ioaddr + RxConfig);
	}
}

static void netdev_timer(unsigned long data)
{
	struct net_device *dev = (struct net_device *)data;
	struct netdev_private *np = (struct netdev_private *)dev->priv;
	long ioaddr = dev->base_addr;
	int next_tick = 10*HZ;

	if (np->msg_level & NETIF_MSG_TIMER)
		printk(KERN_DEBUG "%s: Driver monitor timer tick, status %8.8x.\n",
			   dev->name, (int)readl(ioaddr + IntrStatus));
	if (np->rx_q_empty) {
		/* Trigger an interrupt to refill. */
		writel(SoftIntr, ioaddr + ChipCmd);
	}
	/* This will either have a small false-trigger window or will not catch
	   tbusy incorrectly set when the queue is empty. */
	if (netif_queue_paused(dev)  &&
		np->cur_tx - np->dirty_tx > 1  &&
		(jiffies - dev->trans_start) > TX_TIMEOUT) {
		tx_timeout(dev);
	}
	check_duplex(dev);
	np->timer.expires = jiffies + next_tick;
	add_timer(&np->timer);
}

static void tx_timeout(struct net_device *dev)
{
	struct netdev_private *np = (struct netdev_private *)dev->priv;
	long ioaddr = dev->base_addr;

	printk(KERN_WARNING "%s: Transmit timed out, status %8.8x,"
		   " resetting...\n", dev->name, (int)readl(ioaddr + TxRingPtr));

	if (np->msg_level & NETIF_MSG_TX_ERR) {
		int i;
		printk(KERN_DEBUG "  Rx ring %p: ", np->rx_ring);
		for (i = 0; i < RX_RING_SIZE; i++)
			printk(" %8.8x", (unsigned int)np->rx_ring[i].cmd_status);
		printk("\n"KERN_DEBUG"  Tx ring %p: ", np->tx_ring);
		for (i = 0; i < TX_RING_SIZE; i++)
			printk(" %4.4x", np->tx_ring[i].cmd_status);
		printk("\n");
	}

	/* Reinitialize the hardware here. */
	/* Stop and restart the chip's Tx processes . */

	/* Trigger an immediate transmit demand. */

	dev->trans_start = jiffies;
	np->stats.tx_errors++;
	return;
}

/* Refill the Rx ring buffers, returning non-zero if not full. */
static int rx_ring_fill(struct net_device *dev)
{
	struct netdev_private *np = (struct netdev_private *)dev->priv;
	unsigned int entry;

	for (; np->cur_rx - np->dirty_rx > 0; np->dirty_rx++) {
		entry = np->dirty_rx % RX_RING_SIZE;
		if (np->rx_skbuff[entry] == NULL) {
			struct sk_buff *skb = dev_alloc_skb(np->rx_buf_sz);
			np->rx_skbuff[entry] = skb;
			if (skb == NULL)
				return 1;				/* Better luck next time. */
			skb->dev = dev;			/* Mark as being used by this device. */
			np->rx_ring[entry].buf_addr = virt_to_le32desc(skb->tail);
		}
		np->rx_ring[entry].cmd_status = cpu_to_le32(DescIntr | np->rx_buf_sz);
	}
	return 0;
}

/* Initialize the Rx and Tx rings, along with various 'dev' bits. */
static void init_ring(struct net_device *dev)
{
	struct netdev_private *np = (struct netdev_private *)dev->priv;
	int i;

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

	/* MAX(PKT_BUF_SZ, dev->mtu + 8); */
	/* I know you _want_ to change this without understanding it.  Don't. */
	np->rx_buf_sz = (dev->mtu <= 1532 ? PKT_BUF_SZ : dev->mtu + 8);
	np->rx_head_desc = &np->rx_ring[0];

	/* Initialize all Rx descriptors. */
	for (i = 0; i < RX_RING_SIZE; i++) {
		np->rx_ring[i].next_desc = virt_to_le32desc(&np->rx_ring[i+1]);
		np->rx_ring[i].cmd_status = cpu_to_le32(DescOwn);
		np->rx_skbuff[i] = 0;
	}
	/* Mark the last entry as wrapping the ring. */
	np->rx_ring[i-1].next_desc = virt_to_le32desc(&np->rx_ring[0]);

	for (i = 0; i < TX_RING_SIZE; i++) {
		np->tx_skbuff[i] = 0;
		np->tx_ring[i].next_desc = virt_to_le32desc(&np->tx_ring[i+1]);
		np->tx_ring[i].cmd_status = 0;
	}
	np->tx_ring[i-1].next_desc = virt_to_le32desc(&np->tx_ring[0]);

	/* Fill in the Rx buffers.
	   Allocation failure just leaves a "negative" np->dirty_rx. */
	np->dirty_rx = (unsigned int)(0 - RX_RING_SIZE);
	rx_ring_fill(dev);

	return;
}

static int start_tx(struct sk_buff *skb, struct net_device *dev)
{
	struct netdev_private *np = (struct netdev_private *)dev->priv;
	unsigned int entry;

	/* Block a timer-based transmit from overlapping.  This happens when
	   packets are presumed lost, and we use this check the Tx status. */
	if (netif_pause_tx_queue(dev) != 0) {
		/* This watchdog code is redundant with the media monitor timer. */
		if (jiffies - dev->trans_start > TX_TIMEOUT)
			tx_timeout(dev);
		return 1;
	}

	/* Note: Ordering is important here, set the field with the
	   "ownership" bit last, and only then increment cur_tx.
	   No spinlock is needed for either Tx or Rx.
	*/

	/* Calculate the next Tx descriptor entry. */
	entry = np->cur_tx % TX_RING_SIZE;

	np->tx_skbuff[entry] = skb;

	np->tx_ring[entry].buf_addr = virt_to_le32desc(skb->data);
	np->tx_ring[entry].cmd_status = cpu_to_le32(DescOwn|DescIntr | skb->len);
	np->cur_tx++;

	/* For some architectures explicitly flushing np->tx_ring,sizeof(tx_ring)
	   and skb->data,skb->len improves performance. */

	if (np->cur_tx - np->dirty_tx >= TX_QUEUE_LEN - 1) {
		np->tx_full = 1;
		/* Check for a just-cleared queue. */
		if (np->cur_tx - (volatile unsigned int)np->dirty_tx
			< TX_QUEUE_LEN - 4) {
			np->tx_full = 0;
			netif_unpause_tx_queue(dev);
		} else
			netif_stop_tx_queue(dev);
	} else
		netif_unpause_tx_queue(dev);		/* Typical path */
	/* Wake the potentially-idle transmit channel. */
	writel(TxOn, dev->base_addr + ChipCmd);

	dev->trans_start = jiffies;

	if (np->msg_level & NETIF_MSG_TX_QUEUED) {
		printk(KERN_DEBUG "%s: Transmit frame #%d queued in slot %d.\n",
			   dev->name, np->cur_tx, entry);
	}
	return 0;
}

/* The interrupt handler does all of the Rx thread work and cleans up
   after the Tx thread. */
static void intr_handler(int irq, void *dev_instance, struct pt_regs *rgs)
{
	struct net_device *dev = (struct net_device *)dev_instance;
	struct netdev_private *np;
	long ioaddr;
	int boguscnt;

#ifndef final_version			/* Can never occur. */
	if (dev == NULL) {
		printk (KERN_ERR "Netdev interrupt handler(): IRQ %d for unknown "
				"device.\n", irq);
		return;
	}
#endif

	ioaddr = dev->base_addr;
	np = (struct netdev_private *)dev->priv;
	boguscnt = np->max_interrupt_work;

	do {
		u32 intr_status = readl(ioaddr + IntrStatus);

		if (intr_status == 0 || intr_status == 0xffffffff)
			break;

		/* Acknowledge all of the current interrupt sources ASAP.
		   Nominally the read above accomplishes this, but... */
		writel(intr_status & 0x001ffff, ioaddr + IntrStatus);

		if (np->msg_level & NETIF_MSG_INTR)
			printk(KERN_DEBUG "%s: Interrupt, status %8.8x.\n",
				   dev->name, intr_status);

		if (intr_status & (IntrRxDone | IntrRxIntr)) {
			netdev_rx(dev);
			np->rx_q_empty = rx_ring_fill(dev);
		}

		if (intr_status & (IntrRxIdle | IntrDrv)) {
			unsigned int old_dirty_rx = np->dirty_rx;
			if (rx_ring_fill(dev) == 0)
				np->rx_q_empty = 0;
			/* Restart Rx engine iff we did add a buffer. */
			if (np->dirty_rx != old_dirty_rx)
				writel(RxOn, dev->base_addr + ChipCmd);
		}

		for (; np->cur_tx - np->dirty_tx > 0; np->dirty_tx++) {
			int entry = np->dirty_tx % TX_RING_SIZE;
			int tx_status = le32_to_cpu(np->tx_ring[entry].cmd_status);
			if (tx_status & DescOwn)
				break;
			if (np->msg_level & NETIF_MSG_TX_DONE)
				printk(KERN_DEBUG "%s: Transmit done, Tx status %8.8x.\n",
					   dev->name, tx_status);
			if (tx_status & 0x08000000) {
				np->stats.tx_packets++;
#if LINUX_VERSION_CODE > 0x20127
				np->stats.tx_bytes += np->tx_skbuff[entry]->len;
#endif
			} else {			/* Various Tx errors */
				if (np->msg_level & NETIF_MSG_TX_ERR)
					printk(KERN_DEBUG "%s: Transmit error, Tx status %8.8x.\n",
						   dev->name, tx_status);
				if (tx_status & 0x04010000) np->stats.tx_aborted_errors++;
				if (tx_status & 0x02000000) np->stats.tx_fifo_errors++;
				if (tx_status & 0x01000000) np->stats.tx_carrier_errors++;
				if (tx_status & 0x00200000) np->stats.tx_window_errors++;
				np->stats.tx_errors++;
			}
			/* Free the original skb. */
			dev_free_skb_irq(np->tx_skbuff[entry]);
			np->tx_skbuff[entry] = 0;
		}
		/* Note the 4 slot hysteresis to mark the queue non-full. */
		if (np->tx_full
			&& np->cur_tx - np->dirty_tx < TX_QUEUE_LEN - 4) {
			/* The ring is no longer full, allow new TX entries. */
			np->tx_full = 0;
			netif_resume_tx_queue(dev);
		}

		/* Abnormal error summary/uncommon events handlers. */
		if (intr_status & IntrAbnormalSummary)
			netdev_error(dev, intr_status);

		if (--boguscnt < 0) {
			printk(KERN_WARNING "%s: Too much work at interrupt, "
				   "status=0x%4.4x.\n",
				   dev->name, intr_status);
			np->restore_intr_enable = 1;
			break;
		}
	} while (1);

	if (np->msg_level & NETIF_MSG_INTR)
		printk(KERN_DEBUG "%s: exiting interrupt, status=%#4.4x.\n",
			   dev->name, (int)readl(ioaddr + IntrStatus));

	return;
}

/* This routine is logically part of the interrupt handler, but separated
   for clarity and better register allocation. */
static int netdev_rx(struct net_device *dev)
{
	struct netdev_private *np = (struct netdev_private *)dev->priv;
	int entry = np->cur_rx % RX_RING_SIZE;
	int boguscnt = np->dirty_rx + RX_RING_SIZE - np->cur_rx;
	s32 desc_status = le32_to_cpu(np->rx_head_desc->cmd_status);

	/* If the driver owns the next entry it's a new packet. Send it up. */
	while (desc_status < 0) {		/* e.g. & DescOwn */
		if (np->msg_level & NETIF_MSG_RX_STATUS)
			printk(KERN_DEBUG "  In netdev_rx() entry %d status was %8.8x.\n",
				   entry, desc_status);
		if (--boguscnt < 0)
			break;
		if ((desc_status & (DescMore|DescPktOK|RxTooLong)) != DescPktOK) {
			if (desc_status & DescMore) {
				printk(KERN_WARNING "%s: Oversized(?) Ethernet frame spanned "
					   "multiple buffers, entry %#x status %x.\n",
					   dev->name, np->cur_rx, desc_status);
				np->stats.rx_length_errors++;
			} else {
				/* There was a error. */
				if (np->msg_level & NETIF_MSG_RX_ERR)
					printk(KERN_DEBUG "  netdev_rx() Rx error was %8.8x.\n",
						   desc_status);
				np->stats.rx_errors++;
				if (desc_status & 0x06000000) np->stats.rx_over_errors++;
				if (desc_status & 0x00600000) np->stats.rx_length_errors++;
				if (desc_status & 0x00140000) np->stats.rx_frame_errors++;
				if (desc_status & 0x00080000) np->stats.rx_crc_errors++;
			}
		} else {
			struct sk_buff *skb;
			int pkt_len = (desc_status & 0x0fff) - 4;	/* Omit CRC size. */
			/* Check if the packet is long enough to accept without copying
			   to a minimally-sized skbuff. */
			if (pkt_len < np->rx_copybreak
				&& (skb = dev_alloc_skb(pkt_len + 2)) != NULL) {
				skb->dev = dev;
				skb_reserve(skb, 2);	/* 16 byte align the IP header */
#if defined(HAS_IP_COPYSUM)  ||  (LINUX_VERSION_CODE >= 0x20100)
				eth_copy_and_sum(skb, np->rx_skbuff[entry]->tail, pkt_len, 0);
				skb_put(skb, pkt_len);
#else
				memcpy(skb_put(skb, pkt_len), np->rx_skbuff[entry]->tail,
					   pkt_len);
#endif
			} else {
				skb_put(skb = np->rx_skbuff[entry], pkt_len);
				np->rx_skbuff[entry] = NULL;
			}
			skb->protocol = eth_type_trans(skb, dev);
			/* W/ hardware checksum: skb->ip_summed = CHECKSUM_UNNECESSARY; */
			netif_rx(skb);
			dev->last_rx = jiffies;
			np->stats.rx_packets++;
#if LINUX_VERSION_CODE > 0x20127
			np->stats.rx_bytes += pkt_len;
#endif
		}
		entry = (++np->cur_rx) % RX_RING_SIZE;
		np->rx_head_desc = &np->rx_ring[entry];
		desc_status = le32_to_cpu(np->rx_head_desc->cmd_status);
	}

	/* Refill is now done in the main interrupt loop. */
	return 0;
}

static void netdev_error(struct net_device *dev, int intr_status)
{