xref: /openbmc/linux/drivers/net/usb/usbnet.c (revision 82ced6fd)
1 /*
2  * USB Network driver infrastructure
3  * Copyright (C) 2000-2005 by David Brownell
4  * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19  */
20 
21 /*
22  * This is a generic "USB networking" framework that works with several
23  * kinds of full and high speed networking devices:  host-to-host cables,
24  * smart usb peripherals, and actual Ethernet adapters.
25  *
26  * These devices usually differ in terms of control protocols (if they
27  * even have one!) and sometimes they define new framing to wrap or batch
28  * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
29  * so interface (un)binding, endpoint I/O queues, fault handling, and other
30  * issues can usefully be addressed by this framework.
31  */
32 
33 // #define	DEBUG			// error path messages, extra info
34 // #define	VERBOSE			// more; success messages
35 
36 #include <linux/module.h>
37 #include <linux/init.h>
38 #include <linux/netdevice.h>
39 #include <linux/etherdevice.h>
40 #include <linux/ethtool.h>
41 #include <linux/workqueue.h>
42 #include <linux/mii.h>
43 #include <linux/usb.h>
44 #include <linux/usb/usbnet.h>
45 
46 #define DRIVER_VERSION		"22-Aug-2005"
47 
48 
49 /*-------------------------------------------------------------------------*/
50 
51 /*
52  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
53  * Several dozen bytes of IPv4 data can fit in two such transactions.
54  * One maximum size Ethernet packet takes twenty four of them.
55  * For high speed, each frame comfortably fits almost 36 max size
56  * Ethernet packets (so queues should be bigger).
57  *
58  * REVISIT qlens should be members of 'struct usbnet'; the goal is to
59  * let the USB host controller be busy for 5msec or more before an irq
60  * is required, under load.  Jumbograms change the equation.
61  */
62 #define RX_MAX_QUEUE_MEMORY (60 * 1518)
63 #define	RX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
64 			(RX_MAX_QUEUE_MEMORY/(dev)->rx_urb_size) : 4)
65 #define	TX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
66 			(RX_MAX_QUEUE_MEMORY/(dev)->hard_mtu) : 4)
67 
68 // reawaken network queue this soon after stopping; else watchdog barks
69 #define TX_TIMEOUT_JIFFIES	(5*HZ)
70 
71 // throttle rx/tx briefly after some faults, so khubd might disconnect()
72 // us (it polls at HZ/4 usually) before we report too many false errors.
73 #define THROTTLE_JIFFIES	(HZ/8)
74 
75 // between wakeups
76 #define UNLINK_TIMEOUT_MS	3
77 
78 /*-------------------------------------------------------------------------*/
79 
80 // randomly generated ethernet address
81 static u8	node_id [ETH_ALEN];
82 
83 static const char driver_name [] = "usbnet";
84 
85 /* use ethtool to change the level for any given device */
86 static int msg_level = -1;
87 module_param (msg_level, int, 0);
88 MODULE_PARM_DESC (msg_level, "Override default message level");
89 
90 /*-------------------------------------------------------------------------*/
91 
92 /* handles CDC Ethernet and many other network "bulk data" interfaces */
93 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
94 {
95 	int				tmp;
96 	struct usb_host_interface	*alt = NULL;
97 	struct usb_host_endpoint	*in = NULL, *out = NULL;
98 	struct usb_host_endpoint	*status = NULL;
99 
100 	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
101 		unsigned	ep;
102 
103 		in = out = status = NULL;
104 		alt = intf->altsetting + tmp;
105 
106 		/* take the first altsetting with in-bulk + out-bulk;
107 		 * remember any status endpoint, just in case;
108 		 * ignore other endpoints and altsetttings.
109 		 */
110 		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
111 			struct usb_host_endpoint	*e;
112 			int				intr = 0;
113 
114 			e = alt->endpoint + ep;
115 			switch (e->desc.bmAttributes) {
116 			case USB_ENDPOINT_XFER_INT:
117 				if (!usb_endpoint_dir_in(&e->desc))
118 					continue;
119 				intr = 1;
120 				/* FALLTHROUGH */
121 			case USB_ENDPOINT_XFER_BULK:
122 				break;
123 			default:
124 				continue;
125 			}
126 			if (usb_endpoint_dir_in(&e->desc)) {
127 				if (!intr && !in)
128 					in = e;
129 				else if (intr && !status)
130 					status = e;
131 			} else {
132 				if (!out)
133 					out = e;
134 			}
135 		}
136 		if (in && out)
137 			break;
138 	}
139 	if (!alt || !in || !out)
140 		return -EINVAL;
141 
142 	if (alt->desc.bAlternateSetting != 0
143 			|| !(dev->driver_info->flags & FLAG_NO_SETINT)) {
144 		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
145 				alt->desc.bAlternateSetting);
146 		if (tmp < 0)
147 			return tmp;
148 	}
149 
150 	dev->in = usb_rcvbulkpipe (dev->udev,
151 			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
152 	dev->out = usb_sndbulkpipe (dev->udev,
153 			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
154 	dev->status = status;
155 	return 0;
156 }
157 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
158 
159 static void intr_complete (struct urb *urb);
160 
161 static int init_status (struct usbnet *dev, struct usb_interface *intf)
162 {
163 	char		*buf = NULL;
164 	unsigned	pipe = 0;
165 	unsigned	maxp;
166 	unsigned	period;
167 
168 	if (!dev->driver_info->status)
169 		return 0;
170 
171 	pipe = usb_rcvintpipe (dev->udev,
172 			dev->status->desc.bEndpointAddress
173 				& USB_ENDPOINT_NUMBER_MASK);
174 	maxp = usb_maxpacket (dev->udev, pipe, 0);
175 
176 	/* avoid 1 msec chatter:  min 8 msec poll rate */
177 	period = max ((int) dev->status->desc.bInterval,
178 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
179 
180 	buf = kmalloc (maxp, GFP_KERNEL);
181 	if (buf) {
182 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
183 		if (!dev->interrupt) {
184 			kfree (buf);
185 			return -ENOMEM;
186 		} else {
187 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
188 				buf, maxp, intr_complete, dev, period);
189 			dev_dbg(&intf->dev,
190 				"status ep%din, %d bytes period %d\n",
191 				usb_pipeendpoint(pipe), maxp, period);
192 		}
193 	}
194 	return 0;
195 }
196 
197 /* Passes this packet up the stack, updating its accounting.
198  * Some link protocols batch packets, so their rx_fixup paths
199  * can return clones as well as just modify the original skb.
200  */
201 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
202 {
203 	int	status;
204 
205 	skb->protocol = eth_type_trans (skb, dev->net);
206 	dev->stats.rx_packets++;
207 	dev->stats.rx_bytes += skb->len;
208 
209 	if (netif_msg_rx_status (dev))
210 		devdbg (dev, "< rx, len %zu, type 0x%x",
211 			skb->len + sizeof (struct ethhdr), skb->protocol);
212 	memset (skb->cb, 0, sizeof (struct skb_data));
213 	status = netif_rx (skb);
214 	if (status != NET_RX_SUCCESS && netif_msg_rx_err (dev))
215 		devdbg (dev, "netif_rx status %d", status);
216 }
217 EXPORT_SYMBOL_GPL(usbnet_skb_return);
218 
219 
220 /*-------------------------------------------------------------------------
221  *
222  * Network Device Driver (peer link to "Host Device", from USB host)
223  *
224  *-------------------------------------------------------------------------*/
225 
226 int usbnet_change_mtu (struct net_device *net, int new_mtu)
227 {
228 	struct usbnet	*dev = netdev_priv(net);
229 	int		ll_mtu = new_mtu + net->hard_header_len;
230 	int		old_hard_mtu = dev->hard_mtu;
231 	int		old_rx_urb_size = dev->rx_urb_size;
232 
233 	if (new_mtu <= 0)
234 		return -EINVAL;
235 	// no second zero-length packet read wanted after mtu-sized packets
236 	if ((ll_mtu % dev->maxpacket) == 0)
237 		return -EDOM;
238 	net->mtu = new_mtu;
239 
240 	dev->hard_mtu = net->mtu + net->hard_header_len;
241 	if (dev->rx_urb_size == old_hard_mtu) {
242 		dev->rx_urb_size = dev->hard_mtu;
243 		if (dev->rx_urb_size > old_rx_urb_size)
244 			usbnet_unlink_rx_urbs(dev);
245 	}
246 
247 	return 0;
248 }
249 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
250 
251 /*-------------------------------------------------------------------------*/
252 
253 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
254  * completion callbacks.  2.5 should have fixed those bugs...
255  */
256 
257 static void defer_bh(struct usbnet *dev, struct sk_buff *skb, struct sk_buff_head *list)
258 {
259 	unsigned long		flags;
260 
261 	spin_lock_irqsave(&list->lock, flags);
262 	__skb_unlink(skb, list);
263 	spin_unlock(&list->lock);
264 	spin_lock(&dev->done.lock);
265 	__skb_queue_tail(&dev->done, skb);
266 	if (dev->done.qlen == 1)
267 		tasklet_schedule(&dev->bh);
268 	spin_unlock_irqrestore(&dev->done.lock, flags);
269 }
270 
271 /* some work can't be done in tasklets, so we use keventd
272  *
273  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
274  * but tasklet_schedule() doesn't.  hope the failure is rare.
275  */
276 void usbnet_defer_kevent (struct usbnet *dev, int work)
277 {
278 	set_bit (work, &dev->flags);
279 	if (!schedule_work (&dev->kevent))
280 		deverr (dev, "kevent %d may have been dropped", work);
281 	else
282 		devdbg (dev, "kevent %d scheduled", work);
283 }
284 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
285 
286 /*-------------------------------------------------------------------------*/
287 
288 static void rx_complete (struct urb *urb);
289 
290 static void rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
291 {
292 	struct sk_buff		*skb;
293 	struct skb_data		*entry;
294 	int			retval = 0;
295 	unsigned long		lockflags;
296 	size_t			size = dev->rx_urb_size;
297 
298 	if ((skb = alloc_skb (size + NET_IP_ALIGN, flags)) == NULL) {
299 		if (netif_msg_rx_err (dev))
300 			devdbg (dev, "no rx skb");
301 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
302 		usb_free_urb (urb);
303 		return;
304 	}
305 	skb_reserve (skb, NET_IP_ALIGN);
306 
307 	entry = (struct skb_data *) skb->cb;
308 	entry->urb = urb;
309 	entry->dev = dev;
310 	entry->state = rx_start;
311 	entry->length = 0;
312 
313 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
314 		skb->data, size, rx_complete, skb);
315 
316 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
317 
318 	if (netif_running (dev->net)
319 			&& netif_device_present (dev->net)
320 			&& !test_bit (EVENT_RX_HALT, &dev->flags)) {
321 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
322 		case -EPIPE:
323 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
324 			break;
325 		case -ENOMEM:
326 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
327 			break;
328 		case -ENODEV:
329 			if (netif_msg_ifdown (dev))
330 				devdbg (dev, "device gone");
331 			netif_device_detach (dev->net);
332 			break;
333 		default:
334 			if (netif_msg_rx_err (dev))
335 				devdbg (dev, "rx submit, %d", retval);
336 			tasklet_schedule (&dev->bh);
337 			break;
338 		case 0:
339 			__skb_queue_tail (&dev->rxq, skb);
340 		}
341 	} else {
342 		if (netif_msg_ifdown (dev))
343 			devdbg (dev, "rx: stopped");
344 		retval = -ENOLINK;
345 	}
346 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
347 	if (retval) {
348 		dev_kfree_skb_any (skb);
349 		usb_free_urb (urb);
350 	}
351 }
352 
353 
354 /*-------------------------------------------------------------------------*/
355 
356 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
357 {
358 	if (dev->driver_info->rx_fixup
359 			&& !dev->driver_info->rx_fixup (dev, skb))
360 		goto error;
361 	// else network stack removes extra byte if we forced a short packet
362 
363 	if (skb->len)
364 		usbnet_skb_return (dev, skb);
365 	else {
366 		if (netif_msg_rx_err (dev))
367 			devdbg (dev, "drop");
368 error:
369 		dev->stats.rx_errors++;
370 		skb_queue_tail (&dev->done, skb);
371 	}
372 }
373 
374 /*-------------------------------------------------------------------------*/
375 
376 static void rx_complete (struct urb *urb)
377 {
378 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
379 	struct skb_data		*entry = (struct skb_data *) skb->cb;
380 	struct usbnet		*dev = entry->dev;
381 	int			urb_status = urb->status;
382 
383 	skb_put (skb, urb->actual_length);
384 	entry->state = rx_done;
385 	entry->urb = NULL;
386 
387 	switch (urb_status) {
388 	/* success */
389 	case 0:
390 		if (skb->len < dev->net->hard_header_len) {
391 			entry->state = rx_cleanup;
392 			dev->stats.rx_errors++;
393 			dev->stats.rx_length_errors++;
394 			if (netif_msg_rx_err (dev))
395 				devdbg (dev, "rx length %d", skb->len);
396 		}
397 		break;
398 
399 	/* stalls need manual reset. this is rare ... except that
400 	 * when going through USB 2.0 TTs, unplug appears this way.
401 	 * we avoid the highspeed version of the ETIMEOUT/EILSEQ
402 	 * storm, recovering as needed.
403 	 */
404 	case -EPIPE:
405 		dev->stats.rx_errors++;
406 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
407 		// FALLTHROUGH
408 
409 	/* software-driven interface shutdown */
410 	case -ECONNRESET:		/* async unlink */
411 	case -ESHUTDOWN:		/* hardware gone */
412 		if (netif_msg_ifdown (dev))
413 			devdbg (dev, "rx shutdown, code %d", urb_status);
414 		goto block;
415 
416 	/* we get controller i/o faults during khubd disconnect() delays.
417 	 * throttle down resubmits, to avoid log floods; just temporarily,
418 	 * so we still recover when the fault isn't a khubd delay.
419 	 */
420 	case -EPROTO:
421 	case -ETIME:
422 	case -EILSEQ:
423 		dev->stats.rx_errors++;
424 		if (!timer_pending (&dev->delay)) {
425 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
426 			if (netif_msg_link (dev))
427 				devdbg (dev, "rx throttle %d", urb_status);
428 		}
429 block:
430 		entry->state = rx_cleanup;
431 		entry->urb = urb;
432 		urb = NULL;
433 		break;
434 
435 	/* data overrun ... flush fifo? */
436 	case -EOVERFLOW:
437 		dev->stats.rx_over_errors++;
438 		// FALLTHROUGH
439 
440 	default:
441 		entry->state = rx_cleanup;
442 		dev->stats.rx_errors++;
443 		if (netif_msg_rx_err (dev))
444 			devdbg (dev, "rx status %d", urb_status);
445 		break;
446 	}
447 
448 	defer_bh(dev, skb, &dev->rxq);
449 
450 	if (urb) {
451 		if (netif_running (dev->net)
452 				&& !test_bit (EVENT_RX_HALT, &dev->flags)) {
453 			rx_submit (dev, urb, GFP_ATOMIC);
454 			return;
455 		}
456 		usb_free_urb (urb);
457 	}
458 	if (netif_msg_rx_err (dev))
459 		devdbg (dev, "no read resubmitted");
460 }
461 
462 static void intr_complete (struct urb *urb)
463 {
464 	struct usbnet	*dev = urb->context;
465 	int		status = urb->status;
466 
467 	switch (status) {
468 	/* success */
469 	case 0:
470 		dev->driver_info->status(dev, urb);
471 		break;
472 
473 	/* software-driven interface shutdown */
474 	case -ENOENT:		/* urb killed */
475 	case -ESHUTDOWN:	/* hardware gone */
476 		if (netif_msg_ifdown (dev))
477 			devdbg (dev, "intr shutdown, code %d", status);
478 		return;
479 
480 	/* NOTE:  not throttling like RX/TX, since this endpoint
481 	 * already polls infrequently
482 	 */
483 	default:
484 		devdbg (dev, "intr status %d", status);
485 		break;
486 	}
487 
488 	if (!netif_running (dev->net))
489 		return;
490 
491 	memset(urb->transfer_buffer, 0, urb->transfer_buffer_length);
492 	status = usb_submit_urb (urb, GFP_ATOMIC);
493 	if (status != 0 && netif_msg_timer (dev))
494 		deverr(dev, "intr resubmit --> %d", status);
495 }
496 
497 /*-------------------------------------------------------------------------*/
498 
499 // unlink pending rx/tx; completion handlers do all other cleanup
500 
501 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
502 {
503 	unsigned long		flags;
504 	struct sk_buff		*skb, *skbnext;
505 	int			count = 0;
506 
507 	spin_lock_irqsave (&q->lock, flags);
508 	skb_queue_walk_safe(q, skb, skbnext) {
509 		struct skb_data		*entry;
510 		struct urb		*urb;
511 		int			retval;
512 
513 		entry = (struct skb_data *) skb->cb;
514 		urb = entry->urb;
515 
516 		// during some PM-driven resume scenarios,
517 		// these (async) unlinks complete immediately
518 		retval = usb_unlink_urb (urb);
519 		if (retval != -EINPROGRESS && retval != 0)
520 			devdbg (dev, "unlink urb err, %d", retval);
521 		else
522 			count++;
523 	}
524 	spin_unlock_irqrestore (&q->lock, flags);
525 	return count;
526 }
527 
528 // Flush all pending rx urbs
529 // minidrivers may need to do this when the MTU changes
530 
531 void usbnet_unlink_rx_urbs(struct usbnet *dev)
532 {
533 	if (netif_running(dev->net)) {
534 		(void) unlink_urbs (dev, &dev->rxq);
535 		tasklet_schedule(&dev->bh);
536 	}
537 }
538 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
539 
540 /*-------------------------------------------------------------------------*/
541 
542 // precondition: never called in_interrupt
543 
544 int usbnet_stop (struct net_device *net)
545 {
546 	struct usbnet		*dev = netdev_priv(net);
547 	int			temp;
548 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK (unlink_wakeup);
549 	DECLARE_WAITQUEUE (wait, current);
550 
551 	netif_stop_queue (net);
552 
553 	if (netif_msg_ifdown (dev))
554 		devinfo (dev, "stop stats: rx/tx %ld/%ld, errs %ld/%ld",
555 			dev->stats.rx_packets, dev->stats.tx_packets,
556 			dev->stats.rx_errors, dev->stats.tx_errors
557 			);
558 
559 	// ensure there are no more active urbs
560 	add_wait_queue (&unlink_wakeup, &wait);
561 	dev->wait = &unlink_wakeup;
562 	temp = unlink_urbs (dev, &dev->txq) + unlink_urbs (dev, &dev->rxq);
563 
564 	// maybe wait for deletions to finish.
565 	while (!skb_queue_empty(&dev->rxq)
566 			&& !skb_queue_empty(&dev->txq)
567 			&& !skb_queue_empty(&dev->done)) {
568 		msleep(UNLINK_TIMEOUT_MS);
569 		if (netif_msg_ifdown (dev))
570 			devdbg (dev, "waited for %d urb completions", temp);
571 	}
572 	dev->wait = NULL;
573 	remove_wait_queue (&unlink_wakeup, &wait);
574 
575 	usb_kill_urb(dev->interrupt);
576 
577 	/* deferred work (task, timer, softirq) must also stop.
578 	 * can't flush_scheduled_work() until we drop rtnl (later),
579 	 * else workers could deadlock; so make workers a NOP.
580 	 */
581 	dev->flags = 0;
582 	del_timer_sync (&dev->delay);
583 	tasklet_kill (&dev->bh);
584 	usb_autopm_put_interface(dev->intf);
585 
586 	return 0;
587 }
588 EXPORT_SYMBOL_GPL(usbnet_stop);
589 
590 /*-------------------------------------------------------------------------*/
591 
592 // posts reads, and enables write queuing
593 
594 // precondition: never called in_interrupt
595 
596 int usbnet_open (struct net_device *net)
597 {
598 	struct usbnet		*dev = netdev_priv(net);
599 	int			retval;
600 	struct driver_info	*info = dev->driver_info;
601 
602 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
603 		if (netif_msg_ifup (dev))
604 			devinfo (dev,
605 				"resumption fail (%d) usbnet usb-%s-%s, %s",
606 				retval,
607 				dev->udev->bus->bus_name, dev->udev->devpath,
608 			info->description);
609 		goto done_nopm;
610 	}
611 
612 	// put into "known safe" state
613 	if (info->reset && (retval = info->reset (dev)) < 0) {
614 		if (netif_msg_ifup (dev))
615 			devinfo (dev,
616 				"open reset fail (%d) usbnet usb-%s-%s, %s",
617 				retval,
618 				dev->udev->bus->bus_name, dev->udev->devpath,
619 			info->description);
620 		goto done;
621 	}
622 
623 	// insist peer be connected
624 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
625 		if (netif_msg_ifup (dev))
626 			devdbg (dev, "can't open; %d", retval);
627 		goto done;
628 	}
629 
630 	/* start any status interrupt transfer */
631 	if (dev->interrupt) {
632 		retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
633 		if (retval < 0) {
634 			if (netif_msg_ifup (dev))
635 				deverr (dev, "intr submit %d", retval);
636 			goto done;
637 		}
638 	}
639 
640 	netif_start_queue (net);
641 	if (netif_msg_ifup (dev)) {
642 		char	*framing;
643 
644 		if (dev->driver_info->flags & FLAG_FRAMING_NC)
645 			framing = "NetChip";
646 		else if (dev->driver_info->flags & FLAG_FRAMING_GL)
647 			framing = "GeneSys";
648 		else if (dev->driver_info->flags & FLAG_FRAMING_Z)
649 			framing = "Zaurus";
650 		else if (dev->driver_info->flags & FLAG_FRAMING_RN)
651 			framing = "RNDIS";
652 		else if (dev->driver_info->flags & FLAG_FRAMING_AX)
653 			framing = "ASIX";
654 		else
655 			framing = "simple";
656 
657 		devinfo (dev, "open: enable queueing "
658 				"(rx %d, tx %d) mtu %d %s framing",
659 			(int)RX_QLEN (dev), (int)TX_QLEN (dev), dev->net->mtu,
660 			framing);
661 	}
662 
663 	// delay posting reads until we're fully open
664 	tasklet_schedule (&dev->bh);
665 	return retval;
666 done:
667 	usb_autopm_put_interface(dev->intf);
668 done_nopm:
669 	return retval;
670 }
671 EXPORT_SYMBOL_GPL(usbnet_open);
672 
673 /*-------------------------------------------------------------------------*/
674 
675 /* ethtool methods; minidrivers may need to add some more, but
676  * they'll probably want to use this base set.
677  */
678 
679 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
680 {
681 	struct usbnet *dev = netdev_priv(net);
682 
683 	if (!dev->mii.mdio_read)
684 		return -EOPNOTSUPP;
685 
686 	return mii_ethtool_gset(&dev->mii, cmd);
687 }
688 EXPORT_SYMBOL_GPL(usbnet_get_settings);
689 
690 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
691 {
692 	struct usbnet *dev = netdev_priv(net);
693 	int retval;
694 
695 	if (!dev->mii.mdio_write)
696 		return -EOPNOTSUPP;
697 
698 	retval = mii_ethtool_sset(&dev->mii, cmd);
699 
700 	/* link speed/duplex might have changed */
701 	if (dev->driver_info->link_reset)
702 		dev->driver_info->link_reset(dev);
703 
704 	return retval;
705 
706 }
707 EXPORT_SYMBOL_GPL(usbnet_set_settings);
708 
709 u32 usbnet_get_link (struct net_device *net)
710 {
711 	struct usbnet *dev = netdev_priv(net);
712 
713 	/* If a check_connect is defined, return its result */
714 	if (dev->driver_info->check_connect)
715 		return dev->driver_info->check_connect (dev) == 0;
716 
717 	/* if the device has mii operations, use those */
718 	if (dev->mii.mdio_read)
719 		return mii_link_ok(&dev->mii);
720 
721 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
722 	return ethtool_op_get_link(net);
723 }
724 EXPORT_SYMBOL_GPL(usbnet_get_link);
725 
726 int usbnet_nway_reset(struct net_device *net)
727 {
728 	struct usbnet *dev = netdev_priv(net);
729 
730 	if (!dev->mii.mdio_write)
731 		return -EOPNOTSUPP;
732 
733 	return mii_nway_restart(&dev->mii);
734 }
735 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
736 
737 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
738 {
739 	struct usbnet *dev = netdev_priv(net);
740 
741 	strncpy (info->driver, dev->driver_name, sizeof info->driver);
742 	strncpy (info->version, DRIVER_VERSION, sizeof info->version);
743 	strncpy (info->fw_version, dev->driver_info->description,
744 		sizeof info->fw_version);
745 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
746 }
747 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
748 
749 u32 usbnet_get_msglevel (struct net_device *net)
750 {
751 	struct usbnet *dev = netdev_priv(net);
752 
753 	return dev->msg_enable;
754 }
755 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
756 
757 void usbnet_set_msglevel (struct net_device *net, u32 level)
758 {
759 	struct usbnet *dev = netdev_priv(net);
760 
761 	dev->msg_enable = level;
762 }
763 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
764 
765 /* drivers may override default ethtool_ops in their bind() routine */
766 static struct ethtool_ops usbnet_ethtool_ops = {
767 	.get_settings		= usbnet_get_settings,
768 	.set_settings		= usbnet_set_settings,
769 	.get_link		= usbnet_get_link,
770 	.nway_reset		= usbnet_nway_reset,
771 	.get_drvinfo		= usbnet_get_drvinfo,
772 	.get_msglevel		= usbnet_get_msglevel,
773 	.set_msglevel		= usbnet_set_msglevel,
774 };
775 
776 /*-------------------------------------------------------------------------*/
777 
778 /* work that cannot be done in interrupt context uses keventd.
779  *
780  * NOTE:  with 2.5 we could do more of this using completion callbacks,
781  * especially now that control transfers can be queued.
782  */
783 static void
784 kevent (struct work_struct *work)
785 {
786 	struct usbnet		*dev =
787 		container_of(work, struct usbnet, kevent);
788 	int			status;
789 
790 	/* usb_clear_halt() needs a thread context */
791 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
792 		unlink_urbs (dev, &dev->txq);
793 		status = usb_clear_halt (dev->udev, dev->out);
794 		if (status < 0
795 				&& status != -EPIPE
796 				&& status != -ESHUTDOWN) {
797 			if (netif_msg_tx_err (dev))
798 				deverr (dev, "can't clear tx halt, status %d",
799 					status);
800 		} else {
801 			clear_bit (EVENT_TX_HALT, &dev->flags);
802 			if (status != -ESHUTDOWN)
803 				netif_wake_queue (dev->net);
804 		}
805 	}
806 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
807 		unlink_urbs (dev, &dev->rxq);
808 		status = usb_clear_halt (dev->udev, dev->in);
809 		if (status < 0
810 				&& status != -EPIPE
811 				&& status != -ESHUTDOWN) {
812 			if (netif_msg_rx_err (dev))
813 				deverr (dev, "can't clear rx halt, status %d",
814 					status);
815 		} else {
816 			clear_bit (EVENT_RX_HALT, &dev->flags);
817 			tasklet_schedule (&dev->bh);
818 		}
819 	}
820 
821 	/* tasklet could resubmit itself forever if memory is tight */
822 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
823 		struct urb	*urb = NULL;
824 
825 		if (netif_running (dev->net))
826 			urb = usb_alloc_urb (0, GFP_KERNEL);
827 		else
828 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
829 		if (urb != NULL) {
830 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
831 			rx_submit (dev, urb, GFP_KERNEL);
832 			tasklet_schedule (&dev->bh);
833 		}
834 	}
835 
836 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
837 		struct driver_info	*info = dev->driver_info;
838 		int			retval = 0;
839 
840 		clear_bit (EVENT_LINK_RESET, &dev->flags);
841 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
842 			devinfo(dev, "link reset failed (%d) usbnet usb-%s-%s, %s",
843 				retval,
844 				dev->udev->bus->bus_name, dev->udev->devpath,
845 				info->description);
846 		}
847 	}
848 
849 	if (dev->flags)
850 		devdbg (dev, "kevent done, flags = 0x%lx",
851 			dev->flags);
852 }
853 
854 /*-------------------------------------------------------------------------*/
855 
856 static void tx_complete (struct urb *urb)
857 {
858 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
859 	struct skb_data		*entry = (struct skb_data *) skb->cb;
860 	struct usbnet		*dev = entry->dev;
861 
862 	if (urb->status == 0) {
863 		dev->stats.tx_packets++;
864 		dev->stats.tx_bytes += entry->length;
865 	} else {
866 		dev->stats.tx_errors++;
867 
868 		switch (urb->status) {
869 		case -EPIPE:
870 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
871 			break;
872 
873 		/* software-driven interface shutdown */
874 		case -ECONNRESET:		// async unlink
875 		case -ESHUTDOWN:		// hardware gone
876 			break;
877 
878 		// like rx, tx gets controller i/o faults during khubd delays
879 		// and so it uses the same throttling mechanism.
880 		case -EPROTO:
881 		case -ETIME:
882 		case -EILSEQ:
883 			if (!timer_pending (&dev->delay)) {
884 				mod_timer (&dev->delay,
885 					jiffies + THROTTLE_JIFFIES);
886 				if (netif_msg_link (dev))
887 					devdbg (dev, "tx throttle %d",
888 							urb->status);
889 			}
890 			netif_stop_queue (dev->net);
891 			break;
892 		default:
893 			if (netif_msg_tx_err (dev))
894 				devdbg (dev, "tx err %d", entry->urb->status);
895 			break;
896 		}
897 	}
898 
899 	urb->dev = NULL;
900 	entry->state = tx_done;
901 	defer_bh(dev, skb, &dev->txq);
902 }
903 
904 /*-------------------------------------------------------------------------*/
905 
906 void usbnet_tx_timeout (struct net_device *net)
907 {
908 	struct usbnet		*dev = netdev_priv(net);
909 
910 	unlink_urbs (dev, &dev->txq);
911 	tasklet_schedule (&dev->bh);
912 
913 	// FIXME: device recovery -- reset?
914 }
915 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
916 
917 /*-------------------------------------------------------------------------*/
918 
919 int usbnet_start_xmit (struct sk_buff *skb, struct net_device *net)
920 {
921 	struct usbnet		*dev = netdev_priv(net);
922 	int			length;
923 	int			retval = NET_XMIT_SUCCESS;
924 	struct urb		*urb = NULL;
925 	struct skb_data		*entry;
926 	struct driver_info	*info = dev->driver_info;
927 	unsigned long		flags;
928 
929 	// some devices want funky USB-level framing, for
930 	// win32 driver (usually) and/or hardware quirks
931 	if (info->tx_fixup) {
932 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
933 		if (!skb) {
934 			if (netif_msg_tx_err (dev))
935 				devdbg (dev, "can't tx_fixup skb");
936 			goto drop;
937 		}
938 	}
939 	length = skb->len;
940 
941 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
942 		if (netif_msg_tx_err (dev))
943 			devdbg (dev, "no urb");
944 		goto drop;
945 	}
946 
947 	entry = (struct skb_data *) skb->cb;
948 	entry->urb = urb;
949 	entry->dev = dev;
950 	entry->state = tx_start;
951 	entry->length = length;
952 
953 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
954 			skb->data, skb->len, tx_complete, skb);
955 
956 	/* don't assume the hardware handles USB_ZERO_PACKET
957 	 * NOTE:  strictly conforming cdc-ether devices should expect
958 	 * the ZLP here, but ignore the one-byte packet.
959 	 */
960 	if ((length % dev->maxpacket) == 0) {
961 		urb->transfer_buffer_length++;
962 		if (skb_tailroom(skb)) {
963 			skb->data[skb->len] = 0;
964 			__skb_put(skb, 1);
965 		}
966 	}
967 
968 	spin_lock_irqsave (&dev->txq.lock, flags);
969 
970 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
971 	case -EPIPE:
972 		netif_stop_queue (net);
973 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
974 		break;
975 	default:
976 		if (netif_msg_tx_err (dev))
977 			devdbg (dev, "tx: submit urb err %d", retval);
978 		break;
979 	case 0:
980 		net->trans_start = jiffies;
981 		__skb_queue_tail (&dev->txq, skb);
982 		if (dev->txq.qlen >= TX_QLEN (dev))
983 			netif_stop_queue (net);
984 	}
985 	spin_unlock_irqrestore (&dev->txq.lock, flags);
986 
987 	if (retval) {
988 		if (netif_msg_tx_err (dev))
989 			devdbg (dev, "drop, code %d", retval);
990 drop:
991 		retval = NET_XMIT_SUCCESS;
992 		dev->stats.tx_dropped++;
993 		if (skb)
994 			dev_kfree_skb_any (skb);
995 		usb_free_urb (urb);
996 	} else if (netif_msg_tx_queued (dev)) {
997 		devdbg (dev, "> tx, len %d, type 0x%x",
998 			length, skb->protocol);
999 	}
1000 	return retval;
1001 }
1002 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1003 
1004 /*-------------------------------------------------------------------------*/
1005 
1006 // tasklet (work deferred from completions, in_irq) or timer
1007 
1008 static void usbnet_bh (unsigned long param)
1009 {
1010 	struct usbnet		*dev = (struct usbnet *) param;
1011 	struct sk_buff		*skb;
1012 	struct skb_data		*entry;
1013 
1014 	while ((skb = skb_dequeue (&dev->done))) {
1015 		entry = (struct skb_data *) skb->cb;
1016 		switch (entry->state) {
1017 		case rx_done:
1018 			entry->state = rx_cleanup;
1019 			rx_process (dev, skb);
1020 			continue;
1021 		case tx_done:
1022 		case rx_cleanup:
1023 			usb_free_urb (entry->urb);
1024 			dev_kfree_skb (skb);
1025 			continue;
1026 		default:
1027 			devdbg (dev, "bogus skb state %d", entry->state);
1028 		}
1029 	}
1030 
1031 	// waiting for all pending urbs to complete?
1032 	if (dev->wait) {
1033 		if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
1034 			wake_up (dev->wait);
1035 		}
1036 
1037 	// or are we maybe short a few urbs?
1038 	} else if (netif_running (dev->net)
1039 			&& netif_device_present (dev->net)
1040 			&& !timer_pending (&dev->delay)
1041 			&& !test_bit (EVENT_RX_HALT, &dev->flags)) {
1042 		int	temp = dev->rxq.qlen;
1043 		int	qlen = RX_QLEN (dev);
1044 
1045 		if (temp < qlen) {
1046 			struct urb	*urb;
1047 			int		i;
1048 
1049 			// don't refill the queue all at once
1050 			for (i = 0; i < 10 && dev->rxq.qlen < qlen; i++) {
1051 				urb = usb_alloc_urb (0, GFP_ATOMIC);
1052 				if (urb != NULL)
1053 					rx_submit (dev, urb, GFP_ATOMIC);
1054 			}
1055 			if (temp != dev->rxq.qlen && netif_msg_link (dev))
1056 				devdbg (dev, "rxqlen %d --> %d",
1057 						temp, dev->rxq.qlen);
1058 			if (dev->rxq.qlen < qlen)
1059 				tasklet_schedule (&dev->bh);
1060 		}
1061 		if (dev->txq.qlen < TX_QLEN (dev))
1062 			netif_wake_queue (dev->net);
1063 	}
1064 }
1065 
1066 
1067 
1068 /*-------------------------------------------------------------------------
1069  *
1070  * USB Device Driver support
1071  *
1072  *-------------------------------------------------------------------------*/
1073 
1074 // precondition: never called in_interrupt
1075 
1076 void usbnet_disconnect (struct usb_interface *intf)
1077 {
1078 	struct usbnet		*dev;
1079 	struct usb_device	*xdev;
1080 	struct net_device	*net;
1081 
1082 	dev = usb_get_intfdata(intf);
1083 	usb_set_intfdata(intf, NULL);
1084 	if (!dev)
1085 		return;
1086 
1087 	xdev = interface_to_usbdev (intf);
1088 
1089 	if (netif_msg_probe (dev))
1090 		devinfo (dev, "unregister '%s' usb-%s-%s, %s",
1091 			intf->dev.driver->name,
1092 			xdev->bus->bus_name, xdev->devpath,
1093 			dev->driver_info->description);
1094 
1095 	net = dev->net;
1096 	unregister_netdev (net);
1097 
1098 	/* we don't hold rtnl here ... */
1099 	flush_scheduled_work ();
1100 
1101 	if (dev->driver_info->unbind)
1102 		dev->driver_info->unbind (dev, intf);
1103 
1104 	free_netdev(net);
1105 	usb_put_dev (xdev);
1106 }
1107 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1108 
1109 static const struct net_device_ops usbnet_netdev_ops = {
1110 	.ndo_open		= usbnet_open,
1111 	.ndo_stop		= usbnet_stop,
1112 	.ndo_start_xmit		= usbnet_start_xmit,
1113 	.ndo_tx_timeout		= usbnet_tx_timeout,
1114 	.ndo_change_mtu		= usbnet_change_mtu,
1115 	.ndo_set_mac_address 	= eth_mac_addr,
1116 	.ndo_validate_addr	= eth_validate_addr,
1117 };
1118 
1119 /*-------------------------------------------------------------------------*/
1120 
1121 // precondition: never called in_interrupt
1122 
1123 int
1124 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1125 {
1126 	struct usbnet			*dev;
1127 	struct net_device		*net;
1128 	struct usb_host_interface	*interface;
1129 	struct driver_info		*info;
1130 	struct usb_device		*xdev;
1131 	int				status;
1132 	const char			*name;
1133 
1134 	name = udev->dev.driver->name;
1135 	info = (struct driver_info *) prod->driver_info;
1136 	if (!info) {
1137 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1138 		return -ENODEV;
1139 	}
1140 	xdev = interface_to_usbdev (udev);
1141 	interface = udev->cur_altsetting;
1142 
1143 	usb_get_dev (xdev);
1144 
1145 	status = -ENOMEM;
1146 
1147 	// set up our own records
1148 	net = alloc_etherdev(sizeof(*dev));
1149 	if (!net) {
1150 		dbg ("can't kmalloc dev");
1151 		goto out;
1152 	}
1153 
1154 	dev = netdev_priv(net);
1155 	dev->udev = xdev;
1156 	dev->intf = udev;
1157 	dev->driver_info = info;
1158 	dev->driver_name = name;
1159 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1160 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1161 	skb_queue_head_init (&dev->rxq);
1162 	skb_queue_head_init (&dev->txq);
1163 	skb_queue_head_init (&dev->done);
1164 	dev->bh.func = usbnet_bh;
1165 	dev->bh.data = (unsigned long) dev;
1166 	INIT_WORK (&dev->kevent, kevent);
1167 	dev->delay.function = usbnet_bh;
1168 	dev->delay.data = (unsigned long) dev;
1169 	init_timer (&dev->delay);
1170 	mutex_init (&dev->phy_mutex);
1171 
1172 	dev->net = net;
1173 	strcpy (net->name, "usb%d");
1174 	memcpy (net->dev_addr, node_id, sizeof node_id);
1175 
1176 	/* rx and tx sides can use different message sizes;
1177 	 * bind() should set rx_urb_size in that case.
1178 	 */
1179 	dev->hard_mtu = net->mtu + net->hard_header_len;
1180 #if 0
1181 // dma_supported() is deeply broken on almost all architectures
1182 	// possible with some EHCI controllers
1183 	if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1184 		net->features |= NETIF_F_HIGHDMA;
1185 #endif
1186 
1187 	net->netdev_ops = &usbnet_netdev_ops;
1188 #ifdef CONFIG_COMPAT_NET_DEV_OPS
1189 	net->hard_start_xmit = usbnet_start_xmit;
1190 	net->open = usbnet_open;
1191 	net->stop = usbnet_stop;
1192 	net->tx_timeout = usbnet_tx_timeout;
1193 #endif
1194 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1195 	net->ethtool_ops = &usbnet_ethtool_ops;
1196 
1197 	// allow device-specific bind/init procedures
1198 	// NOTE net->name still not usable ...
1199 	if (info->bind) {
1200 		status = info->bind (dev, udev);
1201 		if (status < 0)
1202 			goto out1;
1203 
1204 		// heuristic:  "usb%d" for links we know are two-host,
1205 		// else "eth%d" when there's reasonable doubt.  userspace
1206 		// can rename the link if it knows better.
1207 		if ((dev->driver_info->flags & FLAG_ETHER) != 0
1208 				&& (net->dev_addr [0] & 0x02) == 0)
1209 			strcpy (net->name, "eth%d");
1210 		/* WLAN devices should always be named "wlan%d" */
1211 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1212 			strcpy(net->name, "wlan%d");
1213 
1214 		/* maybe the remote can't receive an Ethernet MTU */
1215 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1216 			net->mtu = dev->hard_mtu - net->hard_header_len;
1217 	} else if (!info->in || !info->out)
1218 		status = usbnet_get_endpoints (dev, udev);
1219 	else {
1220 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1221 		dev->out = usb_sndbulkpipe (xdev, info->out);
1222 		if (!(info->flags & FLAG_NO_SETINT))
1223 			status = usb_set_interface (xdev,
1224 				interface->desc.bInterfaceNumber,
1225 				interface->desc.bAlternateSetting);
1226 		else
1227 			status = 0;
1228 
1229 	}
1230 	if (status >= 0 && dev->status)
1231 		status = init_status (dev, udev);
1232 	if (status < 0)
1233 		goto out3;
1234 
1235 	if (!dev->rx_urb_size)
1236 		dev->rx_urb_size = dev->hard_mtu;
1237 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1238 
1239 	SET_NETDEV_DEV(net, &udev->dev);
1240 	status = register_netdev (net);
1241 	if (status)
1242 		goto out3;
1243 	if (netif_msg_probe (dev))
1244 		devinfo (dev, "register '%s' at usb-%s-%s, %s, %pM",
1245 			udev->dev.driver->name,
1246 			xdev->bus->bus_name, xdev->devpath,
1247 			dev->driver_info->description,
1248 			net->dev_addr);
1249 
1250 	// ok, it's ready to go.
1251 	usb_set_intfdata (udev, dev);
1252 
1253 	// start as if the link is up
1254 	netif_device_attach (net);
1255 
1256 	return 0;
1257 
1258 out3:
1259 	if (info->unbind)
1260 		info->unbind (dev, udev);
1261 out1:
1262 	free_netdev(net);
1263 out:
1264 	usb_put_dev(xdev);
1265 	return status;
1266 }
1267 EXPORT_SYMBOL_GPL(usbnet_probe);
1268 
1269 /*-------------------------------------------------------------------------*/
1270 
1271 /*
1272  * suspend the whole driver as soon as the first interface is suspended
1273  * resume only when the last interface is resumed
1274  */
1275 
1276 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1277 {
1278 	struct usbnet		*dev = usb_get_intfdata(intf);
1279 
1280 	if (!dev->suspend_count++) {
1281 		/*
1282 		 * accelerate emptying of the rx and queues, to avoid
1283 		 * having everything error out.
1284 		 */
1285 		netif_device_detach (dev->net);
1286 		(void) unlink_urbs (dev, &dev->rxq);
1287 		(void) unlink_urbs (dev, &dev->txq);
1288 		/*
1289 		 * reattach so runtime management can use and
1290 		 * wake the device
1291 		 */
1292 		netif_device_attach (dev->net);
1293 	}
1294 	return 0;
1295 }
1296 EXPORT_SYMBOL_GPL(usbnet_suspend);
1297 
1298 int usbnet_resume (struct usb_interface *intf)
1299 {
1300 	struct usbnet		*dev = usb_get_intfdata(intf);
1301 
1302 	if (!--dev->suspend_count)
1303 		tasklet_schedule (&dev->bh);
1304 
1305 	return 0;
1306 }
1307 EXPORT_SYMBOL_GPL(usbnet_resume);
1308 
1309 
1310 /*-------------------------------------------------------------------------*/
1311 
1312 static int __init usbnet_init(void)
1313 {
1314 	/* compiler should optimize this out */
1315 	BUILD_BUG_ON (sizeof (((struct sk_buff *)0)->cb)
1316 			< sizeof (struct skb_data));
1317 
1318 	random_ether_addr(node_id);
1319 	return 0;
1320 }
1321 module_init(usbnet_init);
1322 
1323 static void __exit usbnet_exit(void)
1324 {
1325 }
1326 module_exit(usbnet_exit);
1327 
1328 MODULE_AUTHOR("David Brownell");
1329 MODULE_DESCRIPTION("USB network driver framework");
1330 MODULE_LICENSE("GPL");
1331