usbnet.c

linux下的usb接口驱动程序

	// put into "known safe" state
	if (info->reset && (retval = info->reset (dev)) < 0) {
		devinfo (dev, "open reset fail (%d) usbnet %03d/%03d, %s",
			retval,
			dev->udev->bus->busnum, dev->udev->devnum,
			info->description);
		goto done;
	}

	// insist peer be connected
	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
		devdbg (dev, "can't open; %d", retval);
		goto done;
	}

	netif_start_queue (net);
	devdbg (dev, "open: enable queueing (rx %d, tx %d) mtu %d %s framing",
		RX_QLEN, TX_QLEN, dev->net.mtu,
		(info->flags & (FLAG_FRAMING_NC | FLAG_FRAMING_GL))
		    ? ((info->flags & FLAG_FRAMING_NC)
			? "NetChip"
			: "GeneSys")
		    : "raw"
		);

	// delay posting reads until we're fully open
	tasklet_schedule (&dev->bh);
done:
	mutex_unlock (&dev->mutex);
	return retval;
}

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

/* usb_clear_halt cannot be called in interrupt context */

static void
tx_clear_halt (void *data)
{
	struct usbnet		*dev = data;

	usb_clear_halt (dev->udev,
		usb_sndbulkpipe (dev->udev, dev->driver_info->out));
	netif_wake_queue (&dev->net);
}

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

static void tx_complete (struct urb *urb)
{
	struct sk_buff		*skb = (struct sk_buff *) urb->context;
	struct skb_data		*entry = (struct skb_data *) skb->cb;
	struct usbnet		*dev = entry->dev;

	if (urb->status == USB_ST_STALL) {
		if (dev->ctrl_task.sync == 0) {
			dev->ctrl_task.routine = tx_clear_halt;
			dev->ctrl_task.data = dev;
			schedule_task (&dev->ctrl_task);
		} else {
			dbg ("Cannot clear TX stall");
		}
	}
	urb->dev = 0;
	entry->state = tx_done;
	defer_bh (dev, skb);
}

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

static void usbnet_tx_timeout (struct net_device *net)
{
	struct usbnet		*dev = (struct usbnet *) net->priv;

	unlink_urbs (&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 = (struct usbnet *) net->priv;
	int			length = skb->len;
	int			retval = NET_XMIT_SUCCESS;
	struct urb		*urb = 0;
	struct skb_data		*entry;
	struct driver_info	*info = dev->driver_info;
	unsigned long		flags;
#ifdef	CONFIG_USB_NET1080
	struct nc_header	*header = 0;
	struct nc_trailer	*trailer = 0;
#endif	/* CONFIG_USB_NET1080 */

	flags = in_interrupt () ? GFP_ATOMIC : GFP_NOIO; /* might be used for nfs */

	// 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, flags);
		if (!skb) {
			dbg ("can't tx_fixup skb");
			goto drop;
		}
	}

	if (!(urb = usb_alloc_urb (0))) {
		dbg ("no urb");
		goto drop;
	}

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

	// FIXME: reorganize a bit, so that fixup() fills out NetChip
	// framing too. (Packet ID update needs the spinlock...)

#ifdef	CONFIG_USB_NET1080
	if (info->flags & FLAG_FRAMING_NC) {
		header = (struct nc_header *) skb_push (skb, sizeof *header);
		header->hdr_len = cpu_to_le16 (sizeof (*header));
		header->packet_len = cpu_to_le16 (length);
		if (!((skb->len + sizeof *trailer) & 0x01))
			*skb_put (skb, 1) = PAD_BYTE;
		trailer = (struct nc_trailer *) skb_put (skb, sizeof *trailer);
	} else
#endif	/* CONFIG_USB_NET1080 */

	/* don't assume the hardware handles USB_ZERO_PACKET */
	if ((length % EP_SIZE (dev)) == 0)
		skb->len++;

	FILL_BULK_URB (urb, dev->udev,
			usb_sndbulkpipe (dev->udev, info->out),
			skb->data, skb->len, tx_complete, skb);
	urb->transfer_flags |= USB_ASYNC_UNLINK;
#ifdef	REALLY_QUEUE
	urb->transfer_flags |= USB_QUEUE_BULK;
#endif
	// FIXME urb->timeout = ... jiffies ... ;

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

#ifdef	CONFIG_USB_NET1080
	if (info->flags & FLAG_FRAMING_NC) {
		header->packet_id = cpu_to_le16 (dev->packet_id++);
		put_unaligned (header->packet_id, &trailer->packet_id);
#if 0
		devdbg (dev, "frame >tx h %d p %d id %d",
			header->hdr_len, header->packet_len,
			header->packet_id);
#endif
	}
#endif	/* CONFIG_USB_NET1080 */

	netif_stop_queue (net);
	if ((retval = usb_submit_urb (urb)) != 0) {
		netif_start_queue (net);
		dbg ("%s tx: submit urb err %d", net->name, retval);
	} else {
		net->trans_start = jiffies;
		__skb_queue_tail (&dev->txq, skb);
		if (dev->txq.qlen < TX_QLEN)
			netif_start_queue (net);
	}
	spin_unlock_irqrestore (&dev->txq.lock, flags);

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


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

// tasklet ... work that avoided running in_irq()

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:
			if (entry->urb->status) {
				// can this statistic become more specific?
				dev->stats.tx_errors++;
				dbg ("%s tx: err %d", dev->net.name,
					entry->urb->status);
			} else {
				dev->stats.tx_packets++;
				dev->stats.tx_bytes += entry->length;
			}
			// FALLTHROUGH:
		    case rx_cleanup:
			usb_free_urb (entry->urb);
			dev_kfree_skb (skb);
			continue;
		    default:
			dbg ("%s: bogus skb state %d",
				dev->net.name, 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)) {
		int	temp = dev->rxq.qlen;

		if (temp < RX_QLEN) {
			struct urb	*urb;
			int		i;
			for (i = 0; i < 3 && dev->rxq.qlen < RX_QLEN; i++) {
				if ((urb = usb_alloc_urb (0)) != 0)
					rx_submit (dev, urb, GFP_ATOMIC);
			}
			if (temp != dev->rxq.qlen)
				devdbg (dev, "rxqlen %d --> %d",
						temp, dev->rxq.qlen);
			if (dev->rxq.qlen < RX_QLEN)
				tasklet_schedule (&dev->bh);
		}
		if (dev->txq.qlen < TX_QLEN)
			netif_wake_queue (&dev->net);
	}
}



/*-------------------------------------------------------------------------
 *
 * USB Device Driver support
 *
 *-------------------------------------------------------------------------*/
 
// precondition: never called in_interrupt

static void usbnet_disconnect (struct usb_device *udev, void *ptr)
{
	struct usbnet	*dev = (struct usbnet *) ptr;

	devinfo (dev, "unregister usbnet %03d/%03d, %s",
		udev->bus->busnum, udev->devnum,
		dev->driver_info->description);
	
	unregister_netdev (&dev->net);

	mutex_lock (&usbnet_mutex);
	mutex_lock (&dev->mutex);
	list_del (&dev->dev_list);
	mutex_unlock (&usbnet_mutex);

	kfree (dev);
	usb_dec_dev_use (udev);
}


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

// precondition: never called in_interrupt

static void *
usbnet_probe (struct usb_device *udev, unsigned ifnum,
			const struct usb_device_id *prod)
{
	struct usbnet			*dev;
	struct net_device 		*net;
	struct usb_interface_descriptor	*interface;
	struct driver_info		*info;
	int				altnum = 0;

	info = (struct driver_info *) prod->driver_info;

	// sanity check; expect dedicated interface/devices for now.
	interface = &udev->actconfig->interface [ifnum].altsetting [altnum];
	if (udev->descriptor.bNumConfigurations != 1
			|| udev->config[0].bNumInterfaces != 1
//			|| interface->bInterfaceClass != USB_CLASS_VENDOR_SPEC
			) {
		dbg ("Bogus config info");
		return 0;
	}

	// more sanity (unless the device is broken)
	if (!(info->flags & FLAG_NO_SETINT)) {
		if (usb_set_interface (udev, ifnum, altnum) < 0) {
			err ("set_interface failed");
			return 0;
		}
	}

	// set up our own records
	if (!(dev = kmalloc (sizeof *dev, GFP_KERNEL))) {
		dbg ("can't kmalloc dev");
		return 0;
	}
	memset (dev, 0, sizeof *dev);

	init_MUTEX_LOCKED (&dev->mutex);
	usb_inc_dev_use (udev);
	dev->udev = udev;
	dev->driver_info = info;
	INIT_LIST_HEAD (&dev->dev_list);
	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;

	// set up network interface records
	net = &dev->net;
	SET_MODULE_OWNER (net);
	net->priv = dev;
	strcpy (net->name, "usb%d");
	memcpy (net->dev_addr, node_id, sizeof node_id);

	// point-to-point link ... we always use Ethernet headers 
	// supports win32 interop and the bridge driver.
	ether_setup (net);

	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;

	register_netdev (&dev->net);
	devinfo (dev, "register usbnet %03d/%03d, %s",
		udev->bus->busnum, udev->devnum,
		dev->driver_info->description);

	// ok, it's ready to go.
	mutex_lock (&usbnet_mutex);
	list_add (&dev->dev_list, &usbnet_list);
	mutex_unlock (&dev->mutex);

	// start as if the link is up
	netif_device_attach (&dev->net);

	mutex_unlock (&usbnet_mutex);
	return dev;
}


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

/*
 * chip vendor names won't normally be on the cables, and
 * may not be on the device.
 */

static const struct usb_device_id	products [] = {

#ifdef	CONFIG_USB_AN2720
{
	USB_DEVICE (0x0547, 0x2720),	// AnchorChips defaults
	driver_info:	(unsigned long) &an2720_info,
},

{
	USB_DEVICE (0x0547, 0x2727),	// Xircom PGUNET
	driver_info:	(unsigned long) &an2720_info,
},
#endif

#ifdef	CONFIG_USB_BELKIN
{
	USB_DEVICE (0x050d, 0x0004),	// Belkin
	driver_info:	(unsigned long) &belkin_info,
}, {
	USB_DEVICE (0x056c, 0x8100),	// eTEK
	driver_info:	(unsigned long) &belkin_info,
}, {
	USB_DEVICE (0x0525, 0x9901),	// Advance USBNET (eTEK)
	driver_info:	(unsigned long) &belkin_info,
},
#endif

#ifdef	CONFIG_USB_GENESYS
{
	USB_DEVICE (0x05e3, 0x0502),	// GL620USB-A
	driver_info:	(unsigned long) &genelink_info,
},
#endif

#ifdef	CONFIG_USB_LINUXDEV
/*
 * for example, this can be a host side talk-to-PDA driver.
 * this driver is NOT what runs _inside_ a Linux device !!
 */
{
	// 1183 = 0x049F, both used as hex values?
	USB_DEVICE (0x049F, 0x505A),	// Compaq "Itsy"
	driver_info:	(unsigned long) &linuxdev_info,
},
#endif

#ifdef	CONFIG_USB_NET1080
{
	USB_DEVICE (0x0525, 0x1080),	// NetChip ref design
	driver_info:	(unsigned long) &net1080_info,
},
{
	USB_DEVICE (0x06D0, 0x0622),	// Laplink Gold
	driver_info:	(unsigned long) &net1080_info,
},
#endif

#ifdef CONFIG_USB_PL2301
{
	USB_DEVICE (0x067b, 0x0000),	// PL-2301
	driver_info:	(unsigned long) &prolific_info,
}, {
	USB_DEVICE (0x067b, 0x0001),	// PL-2302
	driver_info:	(unsigned long) &prolific_info,
},
#endif

/* KC2190 from www.sepoong.co.kr "InstaNET" */

	{ },		// END
};
MODULE_DEVICE_TABLE (usb, products);

static struct usb_driver usbnet_driver = {
	name:		"usbnet",
	id_table:	products,
	probe:		usbnet_probe,
	disconnect:	usbnet_disconnect,
};

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

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

	get_random_bytes (node_id, sizeof node_id);
	node_id [0] &= 0xfe;	// clear multicast bit

 	if (usb_register (&usbnet_driver) < 0)
 		return -1;

	return 0;
}
module_init (usbnet_init);

static void __exit usbnet_exit (void)
{
 	usb_deregister (&usbnet_driver);
}
module_exit (usbnet_exit);

EXPORT_NO_SYMBOLS;
MODULE_AUTHOR ("David Brownell <[e-mail]>");
MODULE_DESCRIPTION ("USB Host-to-Host Link Drivers (numerous vendors)");
MODULE_LICENSE ("GPL");