usbnet.c

omap3 linux 2.6 用nocc去除了冗余代码

		// like rx, tx gets controller i/o faults during khubd delays
		// and so it uses the same throttling mechanism.
		case -EPROTO:
		case -ETIME:
		case -EILSEQ:
			if (!timer_pending (&dev->delay)) {
				mod_timer (&dev->delay,
					jiffies + THROTTLE_JIFFIES);
				if (netif_msg_link (dev))
					devdbg (dev, "tx throttle %d",
							urb->status);
			}
			netif_stop_queue (dev->net);
			break;
		default:
			if (netif_msg_tx_err (dev))
				devdbg (dev, "tx err %d", entry->urb->status);
			break;
		}
	}

	urb->dev = NULL;
	entry->state = tx_done;
	defer_bh(dev, skb, &dev->txq);
}

/*-------------------------------------------------------------------------*/

static void usbnet_tx_timeout (struct net_device *net)
{
	struct usbnet		*dev = netdev_priv(net);

	unlink_urbs (dev, &dev->txq);
	tasklet_schedule (&dev->bh);

	// FIXME: device recovery -- reset?
}

/*-------------------------------------------------------------------------*/

static int usbnet_start_xmit (struct sk_buff *skb, struct net_device *net)
{
	struct usbnet		*dev = netdev_priv(net);
	int			length;
	int			retval = NET_XMIT_SUCCESS;
	struct urb		*urb = NULL;
	struct skb_data		*entry;
	struct driver_info	*info = dev->driver_info;
	unsigned long		flags;

	// some devices want funky USB-level framing, for
	// win32 driver (usually) and/or hardware quirks
	if (info->tx_fixup) {
		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
		if (!skb) {
			if (netif_msg_tx_err (dev))
				devdbg (dev, "can't tx_fixup skb");
			goto drop;
		}
	}
	length = skb->len;

	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
		if (netif_msg_tx_err (dev))
			devdbg (dev, "no urb");
		goto drop;
	}

	entry = (struct skb_data *) skb->cb;
	entry->urb = urb;
	entry->dev = dev;
	entry->state = tx_start;
	entry->length = length;

	usb_fill_bulk_urb (urb, dev->udev, dev->out,
			skb->data, skb->len, tx_complete, skb);

	/* don't assume the hardware handles USB_ZERO_PACKET
	 * NOTE:  strictly conforming cdc-ether devices should expect
	 * the ZLP here, but ignore the one-byte packet.
	 */
	if ((length % dev->maxpacket) == 0) {
		urb->transfer_buffer_length++;
		if (skb_tailroom(skb)) {
			skb->data[skb->len] = 0;
			__skb_put(skb, 1);
		}
	}

	spin_lock_irqsave (&dev->txq.lock, flags);

	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
	case -EPIPE:
		netif_stop_queue (net);
		usbnet_defer_kevent (dev, EVENT_TX_HALT);
		break;
	default:
		if (netif_msg_tx_err (dev))
			devdbg (dev, "tx: submit urb err %d", retval);
		break;
	case 0:
		net->trans_start = jiffies;
		__skb_queue_tail (&dev->txq, skb);
		if (dev->txq.qlen >= TX_QLEN (dev))
			netif_stop_queue (net);
	}
	spin_unlock_irqrestore (&dev->txq.lock, flags);

	if (retval) {
		if (netif_msg_tx_err (dev))
			devdbg (dev, "drop, code %d", retval);
drop:
		retval = NET_XMIT_SUCCESS;
		dev->stats.tx_dropped++;
		if (skb)
			dev_kfree_skb_any (skb);
		usb_free_urb (urb);
	} else if (netif_msg_tx_queued (dev)) {
		devdbg (dev, "> tx, len %d, type 0x%x",
			length, skb->protocol);
	}
	return retval;
}


/*-------------------------------------------------------------------------*/

// tasklet (work deferred from completions, in_irq) or timer

static void usbnet_bh (unsigned long param)
{
	struct usbnet		*dev = (struct usbnet *) param;
	struct sk_buff		*skb;
	struct skb_data		*entry;

	while ((skb = skb_dequeue (&dev->done))) {
		entry = (struct skb_data *) skb->cb;
		switch (entry->state) {
		    case rx_done:
			entry->state = rx_cleanup;
			rx_process (dev, skb);
			continue;
		    case tx_done:
		    case rx_cleanup:
			usb_free_urb (entry->urb);
			dev_kfree_skb (skb);
			continue;
		    default:
			devdbg (dev, "bogus skb state %d", entry->state);
		}
	}

	// waiting for all pending urbs to complete?
	if (dev->wait) {
		if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
			wake_up (dev->wait);
		}

	// or are we maybe short a few urbs?
	} else if (netif_running (dev->net)
			&& netif_device_present (dev->net)
			&& !timer_pending (&dev->delay)
			&& !test_bit (EVENT_RX_HALT, &dev->flags)) {
		int	temp = dev->rxq.qlen;
		int	qlen = RX_QLEN (dev);

		if (temp < qlen) {
			struct urb	*urb;
			int		i;

			// don't refill the queue all at once
			for (i = 0; i < 10 && dev->rxq.qlen < qlen; i++) {
				urb = usb_alloc_urb (0, GFP_ATOMIC);
				if (urb != NULL)
					rx_submit (dev, urb, GFP_ATOMIC);
			}
			if (temp != dev->rxq.qlen && netif_msg_link (dev))
				devdbg (dev, "rxqlen %d --> %d",
						temp, dev->rxq.qlen);
			if (dev->rxq.qlen < qlen)
				tasklet_schedule (&dev->bh);
		}
		if (dev->txq.qlen < TX_QLEN (dev))
			netif_wake_queue (dev->net);
	}
}



/*-------------------------------------------------------------------------
 *
 * USB Device Driver support
 *
 *-------------------------------------------------------------------------*/

// precondition: never called in_interrupt

void usbnet_disconnect (struct usb_interface *intf)
{
	struct usbnet		*dev;
	struct usb_device	*xdev;
	struct net_device	*net;

	dev = usb_get_intfdata(intf);
	usb_set_intfdata(intf, NULL);
	if (!dev)
		return;

	xdev = interface_to_usbdev (intf);

	if (netif_msg_probe (dev))
		devinfo (dev, "unregister '%s' usb-%s-%s, %s",
			intf->dev.driver->name,
			xdev->bus->bus_name, xdev->devpath,
			dev->driver_info->description);

	net = dev->net;
	unregister_netdev (net);

	/* we don't hold rtnl here ... */
	flush_scheduled_work ();

	if (dev->driver_info->unbind)
		dev->driver_info->unbind (dev, intf);

	free_netdev(net);
	usb_put_dev (xdev);
}
EXPORT_SYMBOL_GPL(usbnet_disconnect);


/*-------------------------------------------------------------------------*/

// precondition: never called in_interrupt

int
usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
{
	struct usbnet			*dev;
	struct net_device		*net;
	struct usb_host_interface	*interface;
	struct driver_info		*info;
	struct usb_device		*xdev;
	int				status;
	const char			*name;

	name = udev->dev.driver->name;
	info = (struct driver_info *) prod->driver_info;
	if (!info) {
		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
		return -ENODEV;
	}
	xdev = interface_to_usbdev (udev);
	interface = udev->cur_altsetting;

	usb_get_dev (xdev);

	status = -ENOMEM;

	// set up our own records
	net = alloc_etherdev(sizeof(*dev));
	if (!net) {
		dbg ("can't kmalloc dev");
		goto out;
	}

	dev = netdev_priv(net);
	dev->udev = xdev;
	dev->driver_info = info;
	dev->driver_name = name;
	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
	skb_queue_head_init (&dev->rxq);
	skb_queue_head_init (&dev->txq);
	skb_queue_head_init (&dev->done);
	dev->bh.func = usbnet_bh;
	dev->bh.data = (unsigned long) dev;
	INIT_WORK (&dev->kevent, kevent);
	dev->delay.function = usbnet_bh;
	dev->delay.data = (unsigned long) dev;
	init_timer (&dev->delay);
	mutex_init (&dev->phy_mutex);

	SET_MODULE_OWNER (net);
	dev->net = net;
	strcpy (net->name, "usb%d");
	memcpy (net->dev_addr, node_id, sizeof node_id);

	/* rx and tx sides can use different message sizes;
	 * bind() should set rx_urb_size in that case.
	 */
	dev->hard_mtu = net->mtu + net->hard_header_len;

	net->change_mtu = usbnet_change_mtu;
	net->get_stats = usbnet_get_stats;
	net->hard_start_xmit = usbnet_start_xmit;
	net->open = usbnet_open;
	net->stop = usbnet_stop;
	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
	net->tx_timeout = usbnet_tx_timeout;
	net->ethtool_ops = &usbnet_ethtool_ops;

	// allow device-specific bind/init procedures
	// NOTE net->name still not usable ...
	if (info->bind) {
		status = info->bind (dev, udev);
		if (status < 0)
			goto out1;

		// heuristic:  "usb%d" for links we know are two-host,
		// else "eth%d" when there's reasonable doubt.  userspace
		// can rename the link if it knows better.
		if ((dev->driver_info->flags & FLAG_ETHER) != 0
				&& (net->dev_addr [0] & 0x02) == 0)
			strcpy (net->name, "eth%d");

		/* maybe the remote can't receive an Ethernet MTU */
		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
			net->mtu = dev->hard_mtu - net->hard_header_len;
	} else if (!info->in || !info->out)
		status = usbnet_get_endpoints (dev, udev);
	else {
		dev->in = usb_rcvbulkpipe (xdev, info->in);
		dev->out = usb_sndbulkpipe (xdev, info->out);
		if (!(info->flags & FLAG_NO_SETINT))
			status = usb_set_interface (xdev,
				interface->desc.bInterfaceNumber,
				interface->desc.bAlternateSetting);
		else
			status = 0;

	}
	if (status == 0 && dev->status)
		status = init_status (dev, udev);
	if (status < 0)
		goto out3;

	if (!dev->rx_urb_size)
		dev->rx_urb_size = dev->hard_mtu;
	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);

	SET_NETDEV_DEV(net, &udev->dev);
	status = register_netdev (net);
	if (status)
		goto out3;
	if (netif_msg_probe (dev))
		devinfo (dev, "register '%s' at usb-%s-%s, %s, "
				"%02x:%02x:%02x:%02x:%02x:%02x",
			udev->dev.driver->name,
			xdev->bus->bus_name, xdev->devpath,
			dev->driver_info->description,
			net->dev_addr [0], net->dev_addr [1],
			net->dev_addr [2], net->dev_addr [3],
			net->dev_addr [4], net->dev_addr [5]);

	// ok, it's ready to go.
	usb_set_intfdata (udev, dev);

	// start as if the link is up
	netif_device_attach (net);

	return 0;

out3:
	if (info->unbind)
		info->unbind (dev, udev);
out1:
	free_netdev(net);
out:
	usb_put_dev(xdev);
	return status;
}
EXPORT_SYMBOL_GPL(usbnet_probe);

/*-------------------------------------------------------------------------*/

/*
 * suspend the whole driver as soon as the first interface is suspended
 * resume only when the last interface is resumed
 */

int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
{
	struct usbnet		*dev = usb_get_intfdata(intf);

	if (!dev->suspend_count++) {
		/* accelerate emptying of the rx and queues, to avoid
		 * having everything error out.
		 */
		netif_device_detach (dev->net);
		(void) unlink_urbs (dev, &dev->rxq);
		(void) unlink_urbs (dev, &dev->txq);
	}
	return 0;
}
EXPORT_SYMBOL_GPL(usbnet_suspend);

int usbnet_resume (struct usb_interface *intf)
{
	struct usbnet		*dev = usb_get_intfdata(intf);

	if (!--dev->suspend_count) {
		netif_device_attach (dev->net);
		tasklet_schedule (&dev->bh);
	}
	return 0;
}
EXPORT_SYMBOL_GPL(usbnet_resume);


/*-------------------------------------------------------------------------*/

static int __init usbnet_init(void)
{
	/* compiler should optimize this out */
	BUILD_BUG_ON (sizeof (((struct sk_buff *)0)->cb)
			< sizeof (struct skb_data));

	random_ether_addr(node_id);
	return 0;
}
module_init(usbnet_init);

static void __exit usbnet_exit(void)
{
}
module_exit(usbnet_exit);

MODULE_AUTHOR("David Brownell");
MODULE_DESCRIPTION("USB network driver framework");
MODULE_LICENSE("GPL");