acenic.c

讲述linux的初始化过程

 				ace_issue_cmd(ap->regs, &cmd);
 			} else {
 				writel(0, &((ap->regs)->RxJumboPrd));
 				wmb();
 			}

			ap->jumbo = 0;
			ap->rx_jumbo_skbprd = 0;
			printk(KERN_INFO "%s: Jumbo ring flushed\n",
			       dev->name);
			if (!ap->tx_full)
				netif_wake_queue(dev);
			clear_bit(0, &ap->jumbo_refill_busy);
			break;
		}
		default:
			printk(KERN_ERR "%s: Unhandled event 0x%02x\n",
			       dev->name, ap->evt_ring[evtcsm].evt);
		}
		evtcsm = (evtcsm + 1) % EVT_RING_ENTRIES;
	}

	return evtcsm;
}


static void ace_rx_int(struct net_device *dev, u32 rxretprd, u32 rxretcsm)
{
	struct ace_private *ap = dev->priv;
	u32 idx;
	int mini_count = 0, std_count = 0;

	idx = rxretcsm;

	while (idx != rxretprd) {
		struct ring_info *rip;
		struct sk_buff *skb;
		struct rx_desc *rxdesc, *retdesc;
		u32 skbidx;
		int desc_type, mapsize;
		u16 csum;

		retdesc = &ap->rx_return_ring[idx];
		skbidx = retdesc->idx;
		desc_type = retdesc->flags & (BD_FLG_JUMBO | BD_FLG_MINI);

		switch(desc_type) {
			/*
			 * Normal frames do not have any flags set
			 *
			 * Mini and normal frames arrive frequently,
			 * so use a local counter to avoid doing
			 * atomic operations for each packet arriving.
			 */
		case 0:
			rip = &ap->skb->rx_std_skbuff[skbidx];
			mapsize = ACE_STD_BUFSIZE - (2 + 16);
			rxdesc = &ap->rx_std_ring[skbidx];
			std_count++;
			break;
		case BD_FLG_JUMBO:
			rip = &ap->skb->rx_jumbo_skbuff[skbidx];
			mapsize = ACE_JUMBO_BUFSIZE - (2 + 16);
			rxdesc = &ap->rx_jumbo_ring[skbidx];
			atomic_dec(&ap->cur_jumbo_bufs);
			break;
		case BD_FLG_MINI:
			rip = &ap->skb->rx_mini_skbuff[skbidx];
			mapsize = ACE_MINI_BUFSIZE - (2 + 16);
			rxdesc = &ap->rx_mini_ring[skbidx];
			mini_count++; 
			break;
		default:
			printk(KERN_INFO "%s: unknown frame type (0x%02x) "
			       "returned by NIC\n", dev->name,
			       retdesc->flags);
			goto error;
		}

		skb = rip->skb;
		rip->skb = NULL;
		pci_unmap_single(ap->pdev, rip->mapping, mapsize,
				 PCI_DMA_FROMDEVICE);
		skb_put(skb, retdesc->size);
#if 0
		/* unncessary */
		rxdesc->size = 0;
#endif

		/*
		 * Fly baby, fly!
		 */
		csum = retdesc->tcp_udp_csum;

		skb->dev = dev;
		skb->protocol = eth_type_trans(skb, dev);

		/*
		 * If the checksum is correct and this is not a
		 * fragment, tell the stack that the data is correct.
		 */
		if(!(csum ^ 0xffff) &&
		   (!(((struct iphdr *)skb->data)->frag_off &
		      __constant_htons(IP_MF|IP_OFFSET))))
			skb->ip_summed = CHECKSUM_UNNECESSARY;
		else
			skb->ip_summed = CHECKSUM_NONE;

		netif_rx(skb);		/* send it up */

		ap->stats.rx_packets++;
		ap->stats.rx_bytes += retdesc->size;

		idx = (idx + 1) % RX_RETURN_RING_ENTRIES;
	}

	atomic_sub(std_count, &ap->cur_rx_bufs);
	if (!ACE_IS_TIGON_I(ap))
		atomic_sub(mini_count, &ap->cur_mini_bufs);

 out:
	/*
	 * According to the documentation RxRetCsm is obsolete with
	 * the 12.3.x Firmware - my Tigon I NICs seem to disagree!
	 */
	if (ACE_IS_TIGON_I(ap)) {
		struct ace_regs *regs = ap->regs;
		writel(idx, &regs->RxRetCsm);
	}
	ap->cur_rx = idx;

	return;
 error:
	idx = rxretprd;
	goto out;
}


static void ace_interrupt(int irq, void *dev_id, struct pt_regs *ptregs)
{
	struct ace_private *ap;
	struct ace_regs *regs;
	struct net_device *dev = (struct net_device *)dev_id;
	u32 idx;
	u32 txcsm, rxretcsm, rxretprd;
	u32 evtcsm, evtprd;

	ap = dev->priv;
	regs = ap->regs;

	/*
	 * In case of PCI shared interrupts or spurious interrupts,
	 * we want to make sure it is actually our interrupt before
	 * spending any time in here.
	 */
	if (!(readl(&regs->HostCtrl) & IN_INT))
		return;

	/*
	 * Tell the card not to generate interrupts while we are in here.
	 */
	writel(1, &regs->Mb0Lo);

	/*
	 * There is no conflict between transmit handling in
	 * start_xmit and receive processing, thus there is no reason
	 * to take a spin lock for RX handling. Wait until we start
	 * working on the other stuff - hey we don't need a spin lock
	 * anymore.
	 */
	rxretprd = *ap->rx_ret_prd;
	rxretcsm = ap->cur_rx;

	if (rxretprd != rxretcsm)
		ace_rx_int(dev, rxretprd, rxretcsm);

	txcsm = *ap->tx_csm;
	idx = ap->tx_ret_csm;

	if (txcsm != idx) {
		do {
			struct sk_buff *skb;

			skb = ap->skb->tx_skbuff[idx].skb;
			/*
			 * Race condition between the code cleaning
			 * the tx queue in the interrupt handler and the
			 * interface close,
			 *
			 * This is a kludge that really should be fixed 
			 * by preventing the driver from generating a tx
			 * interrupt when the packet has already been
			 * removed from the tx queue.
			 *
			 * Nailed by Don Dugger and Chip Salzenberg of
			 * VA Linux.
			 */
			if (skb) {
				dma_addr_t mapping;

				mapping = ap->skb->tx_skbuff[idx].mapping;

				ap->stats.tx_packets++;
				ap->stats.tx_bytes += skb->len;
				pci_unmap_single(ap->pdev, mapping, skb->len,
						 PCI_DMA_TODEVICE);
				dev_kfree_skb_irq(skb);

				ap->skb->tx_skbuff[idx].skb = NULL;
			}

			/*
			 * Question here is whether one should not skip
			 * these writes - I have never seen any errors
			 * caused by the NIC actually trying to access
			 * these incorrectly.
			 */
#ifdef ACE_64BIT_PTR
			ap->tx_ring[idx].addr.addrhi = 0;
#endif
			ap->tx_ring[idx].addr.addrlo = 0;
			ap->tx_ring[idx].flagsize = 0;

			idx = (idx + 1) % TX_RING_ENTRIES;
		} while (idx != txcsm);

		/*
		 * Once we actually get to this point the tx ring has
		 * already been trimmed thus it cannot be full!
		 * Ie. skip the comparison of the tx producer vs. the
		 * consumer.
		 */
		if (netif_queue_stopped(dev) && xchg(&ap->tx_full, 0)) {
			/*
			 * This does not need to be atomic (and expensive),
			 * I've seen cases where it would fail otherwise ;-(
			 */
			netif_wake_queue(dev);
			ace_mark_net_bh();

			/*
			 * TX ring is no longer full, aka the
			 * transmitter is working fine - kill timer.
			 */
			del_timer(&ap->timer);
		}

		ap->tx_ret_csm = txcsm;
		wmb();
	}

	evtcsm = readl(&regs->EvtCsm);
	evtprd = *ap->evt_prd;

	if (evtcsm != evtprd) {
		evtcsm = ace_handle_event(dev, evtcsm, evtprd);
		writel(evtcsm, &regs->EvtCsm);
	}

	/*
	 * This has to go last in the interrupt handler and run with
	 * the spin lock released ... what lock?
	 */
	if (netif_running(dev)) {
		int cur_size;
		int run_tasklet = 0;

		cur_size = atomic_read(&ap->cur_rx_bufs);
		if (cur_size < RX_LOW_STD_THRES) {
			if ((cur_size < RX_PANIC_STD_THRES) &&
			    !test_and_set_bit(0, &ap->std_refill_busy)) {
#if DEBUG
				printk("low on std buffers %i\n", cur_size);
#endif
				ace_load_std_rx_ring(ap,
						     RX_RING_SIZE - cur_size);
			} else
				run_tasklet = 1;
		}

		if (!ACE_IS_TIGON_I(ap)) {
			cur_size = atomic_read(&ap->cur_mini_bufs);
			if (cur_size < RX_LOW_MINI_THRES) {
				if ((cur_size < RX_PANIC_MINI_THRES) &&
				    !test_and_set_bit(0,
						      &ap->mini_refill_busy)) {
#if DEBUG
					printk("low on mini buffers %i\n",
					       cur_size);
#endif
					ace_load_mini_rx_ring(ap, RX_MINI_SIZE - cur_size);
				} else
					run_tasklet = 1;
			}
		}

		if (ap->jumbo) {
			cur_size = atomic_read(&ap->cur_jumbo_bufs);
			if (cur_size < RX_LOW_JUMBO_THRES) {
				if ((cur_size < RX_PANIC_JUMBO_THRES) &&
				    !test_and_set_bit(0,
						      &ap->jumbo_refill_busy)){
#if DEBUG
					printk("low on jumbo buffers %i\n",
					       cur_size);
#endif
					ace_load_jumbo_rx_ring(ap, RX_JUMBO_SIZE - cur_size);
				} else
					run_tasklet = 1;
			}
		}
		if (run_tasklet && !ap->tasklet_pending) {
			ap->tasklet_pending = 1;
			tasklet_schedule(&ap->ace_tasklet);
		}
	}

	/*
	 * Allow the card to generate interrupts again
	 */
	writel(0, &regs->Mb0Lo);
}


static int ace_open(struct net_device *dev)
{
	struct ace_private *ap;
	struct ace_regs *regs;
	struct cmd cmd;

	ap = dev->priv;
	regs = ap->regs;

	if (!(ap->fw_running)) {
		printk(KERN_WARNING "%s: Firmware not running!\n", dev->name);
		return -EBUSY;
	}

	writel(dev->mtu + ETH_HLEN + 4, &regs->IfMtu);

	/*
	 * Zero the stats when restarting the interface...
	 */
	memset(&ap->stats, 0, sizeof(ap->stats));

	cmd.evt = C_CLEAR_STATS;
	cmd.code = 0;
	cmd.idx = 0;
	ace_issue_cmd(regs, &cmd);

	cmd.evt = C_HOST_STATE;
	cmd.code = C_C_STACK_UP;
	cmd.idx = 0;
	ace_issue_cmd(regs, &cmd);

	if (ap->jumbo &&
	    !test_and_set_bit(0, &ap->jumbo_refill_busy))
		ace_load_jumbo_rx_ring(ap, RX_JUMBO_SIZE);

	if (dev->flags & IFF_PROMISC) {
		cmd.evt = C_SET_PROMISC_MODE;
		cmd.code = C_C_PROMISC_ENABLE;
		cmd.idx = 0;
		ace_issue_cmd(regs, &cmd);

		ap->promisc = 1;
	}else
		ap->promisc = 0;
	ap->mcast_all = 0;

#if 0
	cmd.evt = C_LNK_NEGOTIATION;
	cmd.code = 0;
	cmd.idx = 0;
	ace_issue_cmd(regs, &cmd);
#endif

	netif_start_queue(dev);

	ACE_MOD_INC_USE_COUNT;

	/*
	 * Setup the timer
	 */
	init_timer(&ap->timer);
	ap->timer.data = (unsigned long)dev;
	ap->timer.function = ace_timer;

	/*
	 * Setup the bottom half rx ring refill handler
	 */
	tasklet_init(&ap->ace_tasklet, ace_tasklet, (unsigned long)dev);
	return 0;
}


static int ace_close(struct net_device *dev)
{
	struct ace_private *ap;
	struct ace_regs *regs;
	struct cmd cmd;
	unsigned long flags;
	short i;

	ace_if_down(dev);
	netif_stop_queue(dev);

	ap = dev->priv;
	regs = ap->regs;

	del_timer(&ap->timer);

	if (ap->promisc) {
		cmd.evt = C_SET_PROMISC_MODE;
		cmd.code = C_C_PROMISC_DISABLE;
		cmd.idx = 0;
		ace_issue_cmd(regs, &cmd);
		ap->promisc = 0;
	}

	cmd.evt = C_HOST_STATE;
	cmd.code = C_C_STACK_DOWN;
	cmd.idx = 0;
	ace_issue_cmd(regs, &cmd);

	tasklet_kill(&ap->ace_tasklet);

	/*
	 * Make sure one CPU is not processing packets while
	 * buffers are being released by another.
	 */
	save_flags(flags);
	cli();

	for (i = 0; i < TX_RING_ENTRIES; i++) {
		struct sk_buff *skb;
		dma_addr_t mapping;

		skb = ap->skb->tx_skbuff[i].skb;
		mapping = ap->skb->tx_skbuff[i].mapping;
		if (skb) {
			memset(&ap->tx_ring[i].addr, 0, sizeof(struct tx_desc));
			pci_unmap_single(ap->pdev, mapping, skb->len,
					 PCI_DMA_TODEVICE);
			dev_kfree_skb(skb);
			ap->skb->tx_skbuff[i].skb = NULL;
		}
	}

	if (ap->jumbo) {
		cmd.evt = C_RESET_JUMBO_RNG;
		cmd.code = 0;
		cmd.idx = 0;
		ace_issue_cmd(regs, &cmd);
	}

	restore_flags(flags);

	ACE_MOD_DEC_USE_COUNT;
	return 0;
}


static int ace_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct ace_private *ap = dev->priv;
	struct ace_regs *regs = ap->regs;
	unsigned long addr;
	u32 idx, flagsize;

	/*
	 * This only happens with pre-softnet, ie. 2.2.x kernels.
	 */
	if (early_stop_netif_stop_queue(dev))
		return 1;

	idx = ap->tx_prd;

	if ((idx + 1) % TX_RING_ENTRIES == ap->tx_ret_csm) {
		ap->tx_full = 1;
#if DEBUG
		printk("%s: trying to transmit while the