atp.c

讲述linux的初始化过程

		} else if (status & ((ISR_TxErr + ISR_TxOK)<<3)) {
			if (net_debug > 6)  printk("handling Tx done..");
			/* Clear the Tx interrupt.  We should check for too many failures
			   and reinitialize the adapter. */
			write_reg(ioaddr, ISR, ISR_TxErr + ISR_TxOK);
			if (status & (ISR_TxErr<<3)) {
				lp->stats.collisions++;
				if (++lp->re_tx > 15) {
					lp->stats.tx_aborted_errors++;
					hardware_init(dev);
					break;
				}
				/* Attempt to retransmit. */
				if (net_debug > 6)  printk("attempting to ReTx");
				write_reg(ioaddr, CMR1, CMR1_ReXmit + CMR1_Xmit);
			} else {
				/* Finish up the transmit. */
				lp->stats.tx_packets++;
				lp->pac_cnt_in_tx_buf--;
				if ( lp->saved_tx_size) {
					trigger_send(ioaddr, lp->saved_tx_size);
					lp->saved_tx_size = 0;
					lp->re_tx = 0;
				} else
					lp->tx_unit_busy = 0;
				netif_wake_queue(dev);	/* Inform upper layers. */
			}
			num_tx_since_rx++;
		} else if (num_tx_since_rx > 8
				   && jiffies > dev->last_rx + HZ) {
			if (net_debug > 2)
				printk(KERN_DEBUG "%s: Missed packet? No Rx after %d Tx and "
					   "%ld jiffies status %02x  CMR1 %02x.\n", dev->name,
					   num_tx_since_rx, jiffies - dev->last_rx, status,
					   (read_nibble(ioaddr, CMR1) >> 3) & 15);
			lp->stats.rx_missed_errors++;
			hardware_init(dev);
			num_tx_since_rx = 0;
			break;
		} else
			break;
    }

	/* This following code fixes a rare (and very difficult to track down)
	   problem where the adapter forgets its ethernet address. */
	{
		int i;
		for (i = 0; i < 6; i++)
			write_reg_byte(ioaddr, PAR0 + i, dev->dev_addr[i]);
#if 0 && defined(TIMED_CHECKER)
		mod_timer(&lp->timer, RUN_AT(TIMED_CHECKER));
#endif
	}

	/* Tell the adapter that it can go back to using the output line as IRQ. */
    write_reg(ioaddr, CMR2, CMR2_IRQOUT);
	/* Enable the physical interrupt line, which is sure to be low until.. */
	outb(Ctrl_SelData + Ctrl_IRQEN, ioaddr + PAR_CONTROL);
	/* .. we enable the interrupt sources. */
	write_reg(ioaddr, IMR, ISR_RxOK | ISR_TxErr | ISR_TxOK);
	write_reg_high(ioaddr, IMR, ISRh_RxErr); 			/* Hmmm, really needed? */

	spin_unlock(&lp->lock);

	if (net_debug > 5) printk("exiting interrupt.\n");
	return;
}

#ifdef TIMED_CHECKER
/* This following code fixes a rare (and very difficult to track down)
   problem where the adapter forgets its ethernet address. */
static void atp_timed_checker(unsigned long data)
{
	struct net_device *dev = (struct net_device *)data;
	long ioaddr = dev->base_addr;
	struct net_local *lp = (struct net_local *)dev->priv;
	int tickssofar = jiffies - lp->last_rx_time;
	int i;

	spin_lock(&lp->lock);
	if (tickssofar > 2*HZ) {
#if 1
		for (i = 0; i < 6; i++)
			write_reg_byte(ioaddr, PAR0 + i, dev->dev_addr[i]);
		lp->last_rx_time = jiffies;
#else
		for (i = 0; i < 6; i++)
			if (read_cmd_byte(ioaddr, PAR0 + i) != atp_timed_dev->dev_addr[i])
				{
			struct net_local *lp = (struct net_local *)atp_timed_dev->priv;
			write_reg_byte(ioaddr, PAR0 + i, atp_timed_dev->dev_addr[i]);
			if (i == 2)
			  lp->stats.tx_errors++;
			else if (i == 3)
			  lp->stats.tx_dropped++;
			else if (i == 4)
			  lp->stats.collisions++;
			else
			  lp->stats.rx_errors++;
		  }
#endif
	}
	spin_unlock(&lp->lock);
	lp->timer.expires = RUN_AT(TIMED_CHECKER);
	add_timer(&lp->timer);
}
#endif

/* We have a good packet(s), get it/them out of the buffers. */
static void net_rx(struct net_device *dev)
{
	struct net_local *lp = (struct net_local *)dev->priv;
	long ioaddr = dev->base_addr;
	struct rx_header rx_head;

	/* Process the received packet. */
	outb(EOC+MAR, ioaddr + PAR_DATA);
	read_block(ioaddr, 8, (unsigned char*)&rx_head, dev->if_port);
	if (net_debug > 5)
		printk(KERN_DEBUG " rx_count %04x %04x %04x %04x..", rx_head.pad,
			   rx_head.rx_count, rx_head.rx_status, rx_head.cur_addr);
	if ((rx_head.rx_status & 0x77) != 0x01) {
		lp->stats.rx_errors++;
		if (rx_head.rx_status & 0x0004) lp->stats.rx_frame_errors++;
		else if (rx_head.rx_status & 0x0002) lp->stats.rx_crc_errors++;
		if (net_debug > 3)
			printk(KERN_DEBUG "%s: Unknown ATP Rx error %04x.\n",
				   dev->name, rx_head.rx_status);
		if  (rx_head.rx_status & 0x0020) {
			lp->stats.rx_fifo_errors++;
			write_reg_high(ioaddr, CMR1, CMR1h_TxENABLE);
			write_reg_high(ioaddr, CMR1, CMR1h_RxENABLE | CMR1h_TxENABLE);
		} else if (rx_head.rx_status & 0x0050)
			hardware_init(dev);
		return;
	} else {
		/* Malloc up new buffer. The "-4" omits the FCS (CRC). */
		int pkt_len = (rx_head.rx_count & 0x7ff) - 4;
		struct sk_buff *skb;

		skb = dev_alloc_skb(pkt_len + 2);
		if (skb == NULL) {
			printk(KERN_ERR "%s: Memory squeeze, dropping packet.\n",
				   dev->name);
			lp->stats.rx_dropped++;
			goto done;
		}
		skb->dev = dev;

		skb_reserve(skb, 2);	/* Align IP on 16 byte boundaries */
		read_block(ioaddr, pkt_len, skb_put(skb,pkt_len), dev->if_port);
		skb->protocol = eth_type_trans(skb, dev);
		netif_rx(skb);
		lp->stats.rx_packets++;
		lp->stats.rx_bytes += pkt_len;
	}
 done:
	write_reg(ioaddr, CMR1, CMR1_NextPkt);
	lp->last_rx_time = jiffies;
	return;
}

static void read_block(long ioaddr, int length, unsigned char *p, int data_mode)
{

	if (data_mode <= 3) { /* Mode 0 or 1 */
		outb(Ctrl_LNibRead, ioaddr + PAR_CONTROL);
		outb(length == 8  ?  RdAddr | HNib | MAR  :  RdAddr | MAR,
			 ioaddr + PAR_DATA);
		if (data_mode <= 1) { /* Mode 0 or 1 */
			do  *p++ = read_byte_mode0(ioaddr);  while (--length > 0);
		} else	/* Mode 2 or 3 */
			do  *p++ = read_byte_mode2(ioaddr);  while (--length > 0);
	} else if (data_mode <= 5)
		do      *p++ = read_byte_mode4(ioaddr);  while (--length > 0);
	else
		do      *p++ = read_byte_mode6(ioaddr);  while (--length > 0);

    outb(EOC+HNib+MAR, ioaddr + PAR_DATA);
	outb(Ctrl_SelData, ioaddr + PAR_CONTROL);
}

/* The inverse routine to net_open(). */
static int
net_close(struct net_device *dev)
{
	struct net_local *lp = (struct net_local *)dev->priv;
	long ioaddr = dev->base_addr;

	netif_stop_queue(dev);

	del_timer_sync(&lp->timer);

	/* Flush the Tx and disable Rx here. */
	lp->addr_mode = CMR2h_OFF;
	write_reg_high(ioaddr, CMR2, CMR2h_OFF);

	/* Free the IRQ line. */
	outb(0x00, ioaddr + PAR_CONTROL);
	free_irq(dev->irq, dev);

	/* Reset the ethernet hardware and activate the printer pass-through. */
	write_reg_high(ioaddr, CMR1, CMR1h_RESET | CMR1h_MUX);
	return 0;
}

/* Get the current statistics.	This may be called with the card open or
   closed. */
static struct net_device_stats *
net_get_stats(struct net_device *dev)
{
	struct net_local *lp = (struct net_local *)dev->priv;
	return &lp->stats;
}

/*
 *	Set or clear the multicast filter for this adapter.
 */

/* The little-endian AUTODIN32 ethernet CRC calculation.
   This is common code and should be moved to net/core/crc.c */
static unsigned const ethernet_polynomial_le = 0xedb88320U;
static inline unsigned ether_crc_le(int length, unsigned char *data)
{
    unsigned int crc = 0xffffffff;	/* Initial value. */
    while(--length >= 0) {
		unsigned char current_octet = *data++;
		int bit;
		for (bit = 8; --bit >= 0; current_octet >>= 1) {
			if ((crc ^ current_octet) & 1) {
				crc >>= 1;
				crc ^= ethernet_polynomial_le;
			} else
				crc >>= 1;
		}
    }
    return crc;
}

static void set_rx_mode_8002(struct net_device *dev)
{
	struct net_local *lp = (struct net_local *)dev->priv;
	long ioaddr = dev->base_addr;

	if ( dev->mc_count > 0 || (dev->flags & (IFF_ALLMULTI|IFF_PROMISC))) {
		/* We must make the kernel realise we had to move
		 *	into promisc mode or we start all out war on
		 *	the cable. - AC
		 */
		dev->flags|=IFF_PROMISC;
		lp->addr_mode = CMR2h_PROMISC;
	} else
		lp->addr_mode = CMR2h_Normal;
	write_reg_high(ioaddr, CMR2, lp->addr_mode);
}

static void set_rx_mode_8012(struct net_device *dev)
{
	struct net_local *lp = (struct net_local *)dev->priv;
	long ioaddr = dev->base_addr;
	unsigned char new_mode, mc_filter[8]; /* Multicast hash filter */
	int i;

	if (dev->flags & IFF_PROMISC) {			/* Set promiscuous. */
		new_mode = CMR2h_PROMISC;
	} else if ((dev->mc_count > 1000)  ||  (dev->flags & IFF_ALLMULTI)) {
		/* Too many to filter perfectly -- accept all multicasts. */
		memset(mc_filter, 0xff, sizeof(mc_filter));
		new_mode = CMR2h_Normal;
	} else {
		struct dev_mc_list *mclist;

		memset(mc_filter, 0, sizeof(mc_filter));
		for (i = 0, mclist = dev->mc_list; mclist && i < dev->mc_count;
			 i++, mclist = mclist->next)
			set_bit(ether_crc_le(ETH_ALEN, mclist->dmi_addr) & 0x3f,
					mc_filter);
		new_mode = CMR2h_Normal;
	}
	lp->addr_mode = new_mode;
    write_reg(ioaddr, CMR2, CMR2_IRQOUT | 0x04); /* Switch to page 1. */
    for (i = 0; i < 8; i++)
		write_reg_byte(ioaddr, i, mc_filter[i]);
	if (net_debug > 2 || 1) {
		lp->addr_mode = 1;
		printk(KERN_DEBUG "%s: Mode %d, setting multicast filter to",
			   dev->name, lp->addr_mode);
		for (i = 0; i < 8; i++)
			printk(" %2.2x", mc_filter[i]);
		printk(".\n");
	}

	write_reg_high(ioaddr, CMR2, lp->addr_mode);
    write_reg(ioaddr, CMR2, CMR2_IRQOUT); /* Switch back to page 0 */
}

static int __init atp_init_module(void) {
	if (debug)					/* Emit version even if no cards detected. */
		printk(KERN_INFO "%s" KERN_INFO "%s", versionA, versionB);
	return atp_init(NULL);
}

static void __exit atp_cleanup_module(void) {
	struct net_device *next_dev;

	while (root_atp_dev) {
		next_dev = ((struct net_local *)root_atp_dev->priv)->next_module;
		unregister_netdev(root_atp_dev);
		/* No need to release_region(), since we never snarf it. */
		kfree(root_atp_dev);
		root_atp_dev = next_dev;
	}
}

module_init(atp_init_module);
module_exit(atp_cleanup_module);