usbnet.c

linux下的usb接口驱动程序

			|| skb->len > FRAMED_SIZE (dev->net.mtu)) {
		dev->stats.rx_frame_errors++;
		dbg ("rx framesize %d range %d..%d mtu %d", skb->len,
			(int)MIN_FRAMED, (int)FRAMED_SIZE (dev->net.mtu),
			dev->net.mtu);
		return 0;
	}

	header = (struct nc_header *) skb->data;
	le16_to_cpus (&header->hdr_len);
	le16_to_cpus (&header->packet_len);
	if (FRAMED_SIZE (header->packet_len) > MAX_PACKET) {
		dev->stats.rx_frame_errors++;
		dbg ("packet too big, %d", header->packet_len);
		return 0;
	} else if (header->hdr_len < MIN_HEADER) {
		dev->stats.rx_frame_errors++;
		dbg ("header too short, %d", header->hdr_len);
		return 0;
	} else if (header->hdr_len > MIN_HEADER) {
		// out of band data for us?
		dbg ("header OOB, %d bytes",
			header->hdr_len - MIN_HEADER);
		// switch (vendor/product ids) { ... }
	}
	skb_pull (skb, header->hdr_len);

	trailer = (struct nc_trailer *)
		(skb->data + skb->len - sizeof *trailer);
	skb_trim (skb, skb->len - sizeof *trailer);

	if ((header->packet_len & 0x01) == 0) {
		if (skb->data [header->packet_len] != PAD_BYTE) {
			dev->stats.rx_frame_errors++;
			dbg ("bad pad");
			return 0;
		}
		skb_trim (skb, skb->len - 1);
	}
	if (skb->len != header->packet_len) {
		dev->stats.rx_frame_errors++;
		dbg ("bad packet len %d (expected %d)",
			skb->len, header->packet_len);
		return 0;
	}
	if (header->packet_id != get_unaligned (&trailer->packet_id)) {
		dev->stats.rx_fifo_errors++;
		dbg ("(2+ dropped) rx packet_id mismatch 0x%x 0x%x",
			header->packet_id, trailer->packet_id);
		return 0;
	}
#if 0
	devdbg (dev, "frame <rx h %d p %d id %d", header->hdr_len,
		header->packet_len, header->packet_id);
#endif
	return 1;
}

static struct sk_buff *
net1080_tx_fixup (struct usbnet *dev, struct sk_buff *skb, int flags)
{
	int			padlen;
	struct sk_buff		*skb2;

	padlen = ((skb->len + sizeof (struct nc_header)
			+ sizeof (struct nc_trailer)) & 0x01) ? 0 : 1;
	if (!skb_cloned (skb)) {
		int	headroom = skb_headroom (skb);
		int	tailroom = skb_tailroom (skb);

		if ((padlen + sizeof (struct nc_trailer)) <= tailroom
			    && sizeof (struct nc_header) <= headroom)
			return skb;

		if ((sizeof (struct nc_header) + padlen
					+ sizeof (struct nc_trailer)) <
				(headroom + tailroom)) {
			skb->data = memmove (skb->head
						+ sizeof (struct nc_header),
					    skb->data, skb->len);
			skb->tail = skb->data + skb->len;
			return skb;
		}
	}
	skb2 = skb_copy_expand (skb,
				sizeof (struct nc_header),
				sizeof (struct nc_trailer) + padlen,
				flags);
	dev_kfree_skb_any (skb);
	return skb2;
}

static const struct driver_info	net1080_info = {
	description:	"NetChip TurboCONNECT",
	flags:		FLAG_FRAMING_NC,
	reset:		net1080_reset,
	check_connect:	net1080_check_connect,
	rx_fixup:	net1080_rx_fixup,
	tx_fixup:	net1080_tx_fixup,

	in: 1, out: 1,		// direction distinguishes these
	epsize:	64,
};

#endif /* CONFIG_USB_NET1080 */



#ifdef CONFIG_USB_PL2301

/*-------------------------------------------------------------------------
 *
 * Prolific PL-2301/PL-2302 driver ... http://www.prolifictech.com
 *
 *-------------------------------------------------------------------------*/

/*
 * Bits 0-4 can be used for software handshaking; they're set from
 * one end, cleared from the other, "read" with the interrupt byte.
 */
#define	PL_S_EN		(1<<7)		/* (feature only) suspend enable */
/* reserved bit -- rx ready (6) ? */
#define	PL_TX_READY	(1<<5)		/* (interrupt only) transmit ready */
#define	PL_RESET_OUT	(1<<4)		/* reset output pipe */
#define	PL_RESET_IN	(1<<3)		/* reset input pipe */
#define	PL_TX_C		(1<<2)		/* transmission complete */
#define	PL_TX_REQ	(1<<1)		/* transmission received */
#define	PL_PEER_E	(1<<0)		/* peer exists */

static inline int
pl_vendor_req (struct usbnet *dev, u8 req, u8 val, u8 index)
{
	return usb_control_msg (dev->udev,
		usb_rcvctrlpipe (dev->udev, 0),
		req,
		USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
		val, index,
		0, 0,
		CONTROL_TIMEOUT_JIFFIES);
}

static inline int
pl_clear_QuickLink_features (struct usbnet *dev, int val)
{
	return pl_vendor_req (dev, 1, (u8) val, 0);
}

static inline int
pl_set_QuickLink_features (struct usbnet *dev, int val)
{
	return pl_vendor_req (dev, 3, (u8) val, 0);
}

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

static int pl_reset (struct usbnet *dev)
{
	return pl_set_QuickLink_features (dev,
		PL_S_EN|PL_RESET_OUT|PL_RESET_IN|PL_PEER_E);
}

static int pl_check_connect (struct usbnet *dev)
{
	// FIXME test interrupt data PL_PEER_E bit
	// plus, there's some handshake done by
	// the prolific win32 driver... 
	dbg ("%s: assuming peer is connected", dev->net.name);
	return 0;
}

static const struct driver_info	prolific_info = {
	description:	"Prolific PL-2301/PL-2302",
	flags:		FLAG_NO_SETINT,
		/* some PL-2302 versions seem to fail usb_set_interface() */
	reset:		pl_reset,
	check_connect:	pl_check_connect,

	in: 3, out: 2,
	epsize:	64,
};

#endif /* CONFIG_USB_PL2301 */



/*-------------------------------------------------------------------------
 *
 * Network Device Driver (peer link to "Host Device", from USB host)
 *
 *-------------------------------------------------------------------------*/

static int usbnet_change_mtu (struct net_device *net, int new_mtu)
{
	struct usbnet	*dev = (struct usbnet *) net->priv;

	if (new_mtu <= MIN_PACKET || new_mtu > MAX_PACKET)
		return -EINVAL;
#ifdef	CONFIG_USB_NET1080
	if (((dev->driver_info->flags) & FLAG_FRAMING_NC)) {
		if (FRAMED_SIZE (new_mtu) > MAX_PACKET)
			return -EINVAL;
	}
#endif
#ifdef	CONFIG_USB_GENESYS
	if (((dev->driver_info->flags) & FLAG_FRAMING_GL)
			&& new_mtu > GL_MAX_PACKET_LEN)
		return -EINVAL;
#endif
	// no second zero-length packet read wanted after mtu-sized packets
	if (((new_mtu + sizeof (struct ethhdr)) % EP_SIZE (dev)) == 0)
		return -EDOM;
	net->mtu = new_mtu;
	return 0;
}

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

static struct net_device_stats *usbnet_get_stats (struct net_device *net)
{
	return &((struct usbnet *) net->priv)->stats;
}

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

/* urb completions are currently in_irq; avoid doing real work then. */

static void defer_bh (struct usbnet *dev, struct sk_buff *skb)
{
	struct sk_buff_head	*list = skb->list;
	unsigned long		flags;

	spin_lock_irqsave (&list->lock, flags);
	__skb_unlink (skb, list);
	spin_unlock (&list->lock);
	spin_lock (&dev->done.lock);
	__skb_queue_tail (&dev->done, skb);
	if (dev->done.qlen == 1)
		tasklet_schedule (&dev->bh);
	spin_unlock_irqrestore (&dev->done.lock, flags);
}

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

static void rx_complete (struct urb *urb);

static void rx_submit (struct usbnet *dev, struct urb *urb, int flags)
{
	struct sk_buff		*skb;
	struct skb_data		*entry;
	int			retval = 0;
	unsigned long		lockflags;
	size_t			size;

#ifdef CONFIG_USB_NET1080
	if (dev->driver_info->flags & FLAG_FRAMING_NC)
		size = FRAMED_SIZE (dev->net.mtu);
	else
#endif
#ifdef CONFIG_USB_GENESYS
	if (dev->driver_info->flags & FLAG_FRAMING_GL)
		size = GL_RCV_BUF_SIZE;
	else
#endif
		size = (sizeof (struct ethhdr) + dev->net.mtu);

	if ((skb = alloc_skb (size, flags)) == 0) {
		dbg ("no rx skb");
		tasklet_schedule (&dev->bh);
		usb_free_urb (urb);
		return;
	}

	entry = (struct skb_data *) skb->cb;
	entry->urb = urb;
	entry->dev = dev;
	entry->state = rx_start;
	entry->length = 0;

	FILL_BULK_URB (urb, dev->udev,
		usb_rcvbulkpipe (dev->udev, dev->driver_info->in),
		skb->data, size, rx_complete, skb);
	urb->transfer_flags |= USB_ASYNC_UNLINK;
#ifdef	REALLY_QUEUE
	urb->transfer_flags |= USB_QUEUE_BULK;
#endif
#if 0
	// Idle-but-posted reads with UHCI really chew up
	// PCI bandwidth unless FSBR is disabled
	urb->transfer_flags |= USB_NO_FSBR;
#endif

	spin_lock_irqsave (&dev->rxq.lock, lockflags);

	if (netif_running (&dev->net)) {
		if ((retval = usb_submit_urb (urb)) != 0) {
			dbg ("%s rx submit, %d", dev->net.name, retval);
			tasklet_schedule (&dev->bh);
		} else {
			__skb_queue_tail (&dev->rxq, skb);
		}
	} else {
		dbg ("rx: stopped");
		retval = -ENOLINK;
	}
	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
	if (retval) {
		dev_kfree_skb_any (skb);
		usb_free_urb (urb);
	}
}


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

static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
{
	if (dev->driver_info->rx_fixup
			&& !dev->driver_info->rx_fixup (dev, skb))
		goto error;
	// else network stack removes extra byte if we forced a short packet

	if (skb->len) {
		int	status;

// FIXME: eth_copy_and_csum "small" packets to new SKB (small < ~200 bytes) ?

		skb->dev = &dev->net;
		skb->protocol = eth_type_trans (skb, &dev->net);
		dev->stats.rx_packets++;
		dev->stats.rx_bytes += skb->len;

#ifdef	VERBOSE
		devdbg (dev, "< rx, len %d, type 0x%x",
			skb->len + sizeof (struct ethhdr), skb->protocol);
#endif
		memset (skb->cb, 0, sizeof (struct skb_data));
		status = netif_rx (skb);
		if (status != NET_RX_SUCCESS)
			devdbg (dev, "netif_rx status %d", status);
	} else {
		dbg ("drop");
error:
		dev->stats.rx_errors++;
		skb_queue_tail (&dev->done, skb);
	}
}

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

static void rx_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;
	int			urb_status = urb->status;

	skb_put (skb, urb->actual_length);
	entry->state = rx_done;
	entry->urb = 0;

	switch (urb_status) {
	    // success
	    case 0:
		if (MIN_PACKET > skb->len || skb->len > MAX_PACKET) {
			entry->state = rx_cleanup;
			dev->stats.rx_errors++;
			dev->stats.rx_length_errors++;
			dbg ("rx length %d", skb->len);
		}
		break;

	    // software-driven interface shutdown
	    case -ECONNRESET:		// usb-ohci, usb-uhci
	    case -ECONNABORTED:		// uhci ... for usb-uhci, INTR
		dbg ("%s shutdown, code %d", dev->net.name, urb_status);
		entry->state = rx_cleanup;
		// do urb frees only in the tasklet
		entry->urb = urb;
		urb = 0;
		break;

	    // data overrun ... flush fifo?
	    case -EOVERFLOW:
		dev->stats.rx_over_errors++;
		// FALLTHROUGH
	    
	    default:
		// on unplug we'll get a burst of ETIMEDOUT/EILSEQ
		// till the khubd gets and handles its interrupt.
		entry->state = rx_cleanup;
		dev->stats.rx_errors++;
		dbg ("%s rx: status %d", dev->net.name, urb_status);
		break;
	}

	defer_bh (dev, skb);

	if (urb) {
		if (netif_running (&dev->net)) {
			rx_submit (dev, urb, GFP_ATOMIC);
			return;
		}
	}
#ifdef	VERBOSE
	dbg ("no read resubmitted");
#endif /* VERBOSE */
}

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

// unlink pending rx/tx; completion handlers do all other cleanup

static int unlink_urbs (struct sk_buff_head *q)
{
	unsigned long		flags;
	struct sk_buff		*skb, *skbnext;
	int			count = 0;

	spin_lock_irqsave (&q->lock, flags);
	for (skb = q->next; skb != (struct sk_buff *) q; skb = skbnext) {
		struct skb_data		*entry;
		struct urb		*urb;
		int			retval;

		entry = (struct skb_data *) skb->cb;
		urb = entry->urb;
		skbnext = skb->next;

		// during some PM-driven resume scenarios,
		// these (async) unlinks complete immediately
		retval = usb_unlink_urb (urb);
		if (retval < 0)
			dbg ("unlink urb err, %d", retval);
		else
			count++;
	}
	spin_unlock_irqrestore (&q->lock, flags);
	return count;
}


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

// precondition: never called in_interrupt

static int usbnet_stop (struct net_device *net)
{
	struct usbnet		*dev = (struct usbnet *) net->priv;
	int			temp;
	DECLARE_WAIT_QUEUE_HEAD (unlink_wakeup); 
	DECLARE_WAITQUEUE (wait, current);

	mutex_lock (&dev->mutex);
	netif_stop_queue (net);

	devdbg (dev, "stop stats: rx/tx %ld/%ld, errs %ld/%ld",
		dev->stats.rx_packets, dev->stats.tx_packets, 
		dev->stats.rx_errors, dev->stats.tx_errors
		);

	// ensure there are no more active urbs
	add_wait_queue (&unlink_wakeup, &wait);
	dev->wait = &unlink_wakeup;
	temp = unlink_urbs (&dev->txq) + unlink_urbs (&dev->rxq);

	// maybe wait for deletions to finish.
	while (skb_queue_len (&dev->rxq)
			&& skb_queue_len (&dev->txq)
			&& skb_queue_len (&dev->done)) {
		set_current_state (TASK_UNINTERRUPTIBLE);
		schedule_timeout (UNLINK_TIMEOUT_JIFFIES);
		dbg ("waited for %d urb completions", temp);
	}
	dev->wait = 0;
	remove_wait_queue (&unlink_wakeup, &wait); 

	mutex_unlock (&dev->mutex);
	return 0;
}

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

// posts reads, and enables write queing

// precondition: never called in_interrupt

static int usbnet_open (struct net_device *net)
{
	struct usbnet		*dev = (struct usbnet *) net->priv;
	int			retval = 0;
	struct driver_info	*info = dev->driver_info;

	mutex_lock (&dev->mutex);