xref: /openbmc/linux/drivers/net/usb/usbnet.c (revision 03ad032bb78b2732b607ed198e951240e1d21e59)
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/ctype.h>
41 #include <linux/ethtool.h>
42 #include <linux/workqueue.h>
43 #include <linux/mii.h>
44 #include <linux/usb.h>
45 #include <linux/usb/usbnet.h>
46 
47 #define DRIVER_VERSION		"22-Aug-2005"
48 
49 
50 /*-------------------------------------------------------------------------*/
51 
52 /*
53  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
54  * Several dozen bytes of IPv4 data can fit in two such transactions.
55  * One maximum size Ethernet packet takes twenty four of them.
56  * For high speed, each frame comfortably fits almost 36 max size
57  * Ethernet packets (so queues should be bigger).
58  *
59  * REVISIT qlens should be members of 'struct usbnet'; the goal is to
60  * let the USB host controller be busy for 5msec or more before an irq
61  * is required, under load.  Jumbograms change the equation.
62  */
63 #define RX_MAX_QUEUE_MEMORY (60 * 1518)
64 #define	RX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
65 			(RX_MAX_QUEUE_MEMORY/(dev)->rx_urb_size) : 4)
66 #define	TX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
67 			(RX_MAX_QUEUE_MEMORY/(dev)->hard_mtu) : 4)
68 
69 // reawaken network queue this soon after stopping; else watchdog barks
70 #define TX_TIMEOUT_JIFFIES	(5*HZ)
71 
72 // throttle rx/tx briefly after some faults, so khubd might disconnect()
73 // us (it polls at HZ/4 usually) before we report too many false errors.
74 #define THROTTLE_JIFFIES	(HZ/8)
75 
76 // between wakeups
77 #define UNLINK_TIMEOUT_MS	3
78 
79 /*-------------------------------------------------------------------------*/
80 
81 // randomly generated ethernet address
82 static u8	node_id [ETH_ALEN];
83 
84 static const char driver_name [] = "usbnet";
85 
86 /* use ethtool to change the level for any given device */
87 static int msg_level = -1;
88 module_param (msg_level, int, 0);
89 MODULE_PARM_DESC (msg_level, "Override default message level");
90 
91 /*-------------------------------------------------------------------------*/
92 
93 /* handles CDC Ethernet and many other network "bulk data" interfaces */
94 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
95 {
96 	int				tmp;
97 	struct usb_host_interface	*alt = NULL;
98 	struct usb_host_endpoint	*in = NULL, *out = NULL;
99 	struct usb_host_endpoint	*status = NULL;
100 
101 	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
102 		unsigned	ep;
103 
104 		in = out = status = NULL;
105 		alt = intf->altsetting + tmp;
106 
107 		/* take the first altsetting with in-bulk + out-bulk;
108 		 * remember any status endpoint, just in case;
109 		 * ignore other endpoints and altsetttings.
110 		 */
111 		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
112 			struct usb_host_endpoint	*e;
113 			int				intr = 0;
114 
115 			e = alt->endpoint + ep;
116 			switch (e->desc.bmAttributes) {
117 			case USB_ENDPOINT_XFER_INT:
118 				if (!usb_endpoint_dir_in(&e->desc))
119 					continue;
120 				intr = 1;
121 				/* FALLTHROUGH */
122 			case USB_ENDPOINT_XFER_BULK:
123 				break;
124 			default:
125 				continue;
126 			}
127 			if (usb_endpoint_dir_in(&e->desc)) {
128 				if (!intr && !in)
129 					in = e;
130 				else if (intr && !status)
131 					status = e;
132 			} else {
133 				if (!out)
134 					out = e;
135 			}
136 		}
137 		if (in && out)
138 			break;
139 	}
140 	if (!alt || !in || !out)
141 		return -EINVAL;
142 
143 	if (alt->desc.bAlternateSetting != 0
144 			|| !(dev->driver_info->flags & FLAG_NO_SETINT)) {
145 		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
146 				alt->desc.bAlternateSetting);
147 		if (tmp < 0)
148 			return tmp;
149 	}
150 
151 	dev->in = usb_rcvbulkpipe (dev->udev,
152 			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
153 	dev->out = usb_sndbulkpipe (dev->udev,
154 			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
155 	dev->status = status;
156 	return 0;
157 }
158 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
159 
160 static u8 nibble(unsigned char c)
161 {
162 	if (likely(isdigit(c)))
163 		return c - '0';
164 	c = toupper(c);
165 	if (likely(isxdigit(c)))
166 		return 10 + c - 'A';
167 	return 0;
168 }
169 
170 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
171 {
172 	int 		tmp, i;
173 	unsigned char	buf [13];
174 
175 	tmp = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
176 	if (tmp != 12) {
177 		dev_dbg(&dev->udev->dev,
178 			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
179 		if (tmp >= 0)
180 			tmp = -EINVAL;
181 		return tmp;
182 	}
183 	for (i = tmp = 0; i < 6; i++, tmp += 2)
184 		dev->net->dev_addr [i] =
185 			(nibble(buf [tmp]) << 4) + nibble(buf [tmp + 1]);
186 	return 0;
187 }
188 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
189 
190 static void intr_complete (struct urb *urb);
191 
192 static int init_status (struct usbnet *dev, struct usb_interface *intf)
193 {
194 	char		*buf = NULL;
195 	unsigned	pipe = 0;
196 	unsigned	maxp;
197 	unsigned	period;
198 
199 	if (!dev->driver_info->status)
200 		return 0;
201 
202 	pipe = usb_rcvintpipe (dev->udev,
203 			dev->status->desc.bEndpointAddress
204 				& USB_ENDPOINT_NUMBER_MASK);
205 	maxp = usb_maxpacket (dev->udev, pipe, 0);
206 
207 	/* avoid 1 msec chatter:  min 8 msec poll rate */
208 	period = max ((int) dev->status->desc.bInterval,
209 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
210 
211 	buf = kmalloc (maxp, GFP_KERNEL);
212 	if (buf) {
213 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
214 		if (!dev->interrupt) {
215 			kfree (buf);
216 			return -ENOMEM;
217 		} else {
218 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
219 				buf, maxp, intr_complete, dev, period);
220 			dev_dbg(&intf->dev,
221 				"status ep%din, %d bytes period %d\n",
222 				usb_pipeendpoint(pipe), maxp, period);
223 		}
224 	}
225 	return 0;
226 }
227 
228 /* Passes this packet up the stack, updating its accounting.
229  * Some link protocols batch packets, so their rx_fixup paths
230  * can return clones as well as just modify the original skb.
231  */
232 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
233 {
234 	int	status;
235 
236 	skb->protocol = eth_type_trans (skb, dev->net);
237 	dev->stats.rx_packets++;
238 	dev->stats.rx_bytes += skb->len;
239 
240 	if (netif_msg_rx_status (dev))
241 		devdbg (dev, "< rx, len %zu, type 0x%x",
242 			skb->len + sizeof (struct ethhdr), skb->protocol);
243 	memset (skb->cb, 0, sizeof (struct skb_data));
244 	status = netif_rx (skb);
245 	if (status != NET_RX_SUCCESS && netif_msg_rx_err (dev))
246 		devdbg (dev, "netif_rx status %d", status);
247 }
248 EXPORT_SYMBOL_GPL(usbnet_skb_return);
249 
250 
251 /*-------------------------------------------------------------------------
252  *
253  * Network Device Driver (peer link to "Host Device", from USB host)
254  *
255  *-------------------------------------------------------------------------*/
256 
257 int usbnet_change_mtu (struct net_device *net, int new_mtu)
258 {
259 	struct usbnet	*dev = netdev_priv(net);
260 	int		ll_mtu = new_mtu + net->hard_header_len;
261 	int		old_hard_mtu = dev->hard_mtu;
262 	int		old_rx_urb_size = dev->rx_urb_size;
263 
264 	if (new_mtu <= 0)
265 		return -EINVAL;
266 	// no second zero-length packet read wanted after mtu-sized packets
267 	if ((ll_mtu % dev->maxpacket) == 0)
268 		return -EDOM;
269 	net->mtu = new_mtu;
270 
271 	dev->hard_mtu = net->mtu + net->hard_header_len;
272 	if (dev->rx_urb_size == old_hard_mtu) {
273 		dev->rx_urb_size = dev->hard_mtu;
274 		if (dev->rx_urb_size > old_rx_urb_size)
275 			usbnet_unlink_rx_urbs(dev);
276 	}
277 
278 	return 0;
279 }
280 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
281 
282 /*-------------------------------------------------------------------------*/
283 
284 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
285  * completion callbacks.  2.5 should have fixed those bugs...
286  */
287 
288 static void defer_bh(struct usbnet *dev, struct sk_buff *skb, struct sk_buff_head *list)
289 {
290 	unsigned long		flags;
291 
292 	spin_lock_irqsave(&list->lock, flags);
293 	__skb_unlink(skb, list);
294 	spin_unlock(&list->lock);
295 	spin_lock(&dev->done.lock);
296 	__skb_queue_tail(&dev->done, skb);
297 	if (dev->done.qlen == 1)
298 		tasklet_schedule(&dev->bh);
299 	spin_unlock_irqrestore(&dev->done.lock, flags);
300 }
301 
302 /* some work can't be done in tasklets, so we use keventd
303  *
304  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
305  * but tasklet_schedule() doesn't.  hope the failure is rare.
306  */
307 void usbnet_defer_kevent (struct usbnet *dev, int work)
308 {
309 	set_bit (work, &dev->flags);
310 	if (!schedule_work (&dev->kevent))
311 		deverr (dev, "kevent %d may have been dropped", work);
312 	else
313 		devdbg (dev, "kevent %d scheduled", work);
314 }
315 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
316 
317 /*-------------------------------------------------------------------------*/
318 
319 static void rx_complete (struct urb *urb);
320 
321 static void rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
322 {
323 	struct sk_buff		*skb;
324 	struct skb_data		*entry;
325 	int			retval = 0;
326 	unsigned long		lockflags;
327 	size_t			size = dev->rx_urb_size;
328 
329 	if ((skb = alloc_skb (size + NET_IP_ALIGN, flags)) == NULL) {
330 		if (netif_msg_rx_err (dev))
331 			devdbg (dev, "no rx skb");
332 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
333 		usb_free_urb (urb);
334 		return;
335 	}
336 	skb_reserve (skb, NET_IP_ALIGN);
337 
338 	entry = (struct skb_data *) skb->cb;
339 	entry->urb = urb;
340 	entry->dev = dev;
341 	entry->state = rx_start;
342 	entry->length = 0;
343 
344 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
345 		skb->data, size, rx_complete, skb);
346 
347 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
348 
349 	if (netif_running (dev->net)
350 			&& netif_device_present (dev->net)
351 			&& !test_bit (EVENT_RX_HALT, &dev->flags)) {
352 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
353 		case -EPIPE:
354 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
355 			break;
356 		case -ENOMEM:
357 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
358 			break;
359 		case -ENODEV:
360 			if (netif_msg_ifdown (dev))
361 				devdbg (dev, "device gone");
362 			netif_device_detach (dev->net);
363 			break;
364 		default:
365 			if (netif_msg_rx_err (dev))
366 				devdbg (dev, "rx submit, %d", retval);
367 			tasklet_schedule (&dev->bh);
368 			break;
369 		case 0:
370 			__skb_queue_tail (&dev->rxq, skb);
371 		}
372 	} else {
373 		if (netif_msg_ifdown (dev))
374 			devdbg (dev, "rx: stopped");
375 		retval = -ENOLINK;
376 	}
377 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
378 	if (retval) {
379 		dev_kfree_skb_any (skb);
380 		usb_free_urb (urb);
381 	}
382 }
383 
384 
385 /*-------------------------------------------------------------------------*/
386 
387 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
388 {
389 	if (dev->driver_info->rx_fixup
390 			&& !dev->driver_info->rx_fixup (dev, skb))
391 		goto error;
392 	// else network stack removes extra byte if we forced a short packet
393 
394 	if (skb->len)
395 		usbnet_skb_return (dev, skb);
396 	else {
397 		if (netif_msg_rx_err (dev))
398 			devdbg (dev, "drop");
399 error:
400 		dev->stats.rx_errors++;
401 		skb_queue_tail (&dev->done, skb);
402 	}
403 }
404 
405 /*-------------------------------------------------------------------------*/
406 
407 static void rx_complete (struct urb *urb)
408 {
409 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
410 	struct skb_data		*entry = (struct skb_data *) skb->cb;
411 	struct usbnet		*dev = entry->dev;
412 	int			urb_status = urb->status;
413 
414 	skb_put (skb, urb->actual_length);
415 	entry->state = rx_done;
416 	entry->urb = NULL;
417 
418 	switch (urb_status) {
419 	/* success */
420 	case 0:
421 		if (skb->len < dev->net->hard_header_len) {
422 			entry->state = rx_cleanup;
423 			dev->stats.rx_errors++;
424 			dev->stats.rx_length_errors++;
425 			if (netif_msg_rx_err (dev))
426 				devdbg (dev, "rx length %d", skb->len);
427 		}
428 		break;
429 
430 	/* stalls need manual reset. this is rare ... except that
431 	 * when going through USB 2.0 TTs, unplug appears this way.
432 	 * we avoid the highspeed version of the ETIMEOUT/EILSEQ
433 	 * storm, recovering as needed.
434 	 */
435 	case -EPIPE:
436 		dev->stats.rx_errors++;
437 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
438 		// FALLTHROUGH
439 
440 	/* software-driven interface shutdown */
441 	case -ECONNRESET:		/* async unlink */
442 	case -ESHUTDOWN:		/* hardware gone */
443 		if (netif_msg_ifdown (dev))
444 			devdbg (dev, "rx shutdown, code %d", urb_status);
445 		goto block;
446 
447 	/* we get controller i/o faults during khubd disconnect() delays.
448 	 * throttle down resubmits, to avoid log floods; just temporarily,
449 	 * so we still recover when the fault isn't a khubd delay.
450 	 */
451 	case -EPROTO:
452 	case -ETIME:
453 	case -EILSEQ:
454 		dev->stats.rx_errors++;
455 		if (!timer_pending (&dev->delay)) {
456 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
457 			if (netif_msg_link (dev))
458 				devdbg (dev, "rx throttle %d", urb_status);
459 		}
460 block:
461 		entry->state = rx_cleanup;
462 		entry->urb = urb;
463 		urb = NULL;
464 		break;
465 
466 	/* data overrun ... flush fifo? */
467 	case -EOVERFLOW:
468 		dev->stats.rx_over_errors++;
469 		// FALLTHROUGH
470 
471 	default:
472 		entry->state = rx_cleanup;
473 		dev->stats.rx_errors++;
474 		if (netif_msg_rx_err (dev))
475 			devdbg (dev, "rx status %d", urb_status);
476 		break;
477 	}
478 
479 	defer_bh(dev, skb, &dev->rxq);
480 
481 	if (urb) {
482 		if (netif_running (dev->net)
483 				&& !test_bit (EVENT_RX_HALT, &dev->flags)) {
484 			rx_submit (dev, urb, GFP_ATOMIC);
485 			return;
486 		}
487 		usb_free_urb (urb);
488 	}
489 	if (netif_msg_rx_err (dev))
490 		devdbg (dev, "no read resubmitted");
491 }
492 
493 static void intr_complete (struct urb *urb)
494 {
495 	struct usbnet	*dev = urb->context;
496 	int		status = urb->status;
497 
498 	switch (status) {
499 	/* success */
500 	case 0:
501 		dev->driver_info->status(dev, urb);
502 		break;
503 
504 	/* software-driven interface shutdown */
505 	case -ENOENT:		/* urb killed */
506 	case -ESHUTDOWN:	/* hardware gone */
507 		if (netif_msg_ifdown (dev))
508 			devdbg (dev, "intr shutdown, code %d", status);
509 		return;
510 
511 	/* NOTE:  not throttling like RX/TX, since this endpoint
512 	 * already polls infrequently
513 	 */
514 	default:
515 		devdbg (dev, "intr status %d", status);
516 		break;
517 	}
518 
519 	if (!netif_running (dev->net))
520 		return;
521 
522 	memset(urb->transfer_buffer, 0, urb->transfer_buffer_length);
523 	status = usb_submit_urb (urb, GFP_ATOMIC);
524 	if (status != 0 && netif_msg_timer (dev))
525 		deverr(dev, "intr resubmit --> %d", status);
526 }
527 
528 /*-------------------------------------------------------------------------*/
529 
530 // unlink pending rx/tx; completion handlers do all other cleanup
531 
532 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
533 {
534 	unsigned long		flags;
535 	struct sk_buff		*skb, *skbnext;
536 	int			count = 0;
537 
538 	spin_lock_irqsave (&q->lock, flags);
539 	skb_queue_walk_safe(q, skb, skbnext) {
540 		struct skb_data		*entry;
541 		struct urb		*urb;
542 		int			retval;
543 
544 		entry = (struct skb_data *) skb->cb;
545 		urb = entry->urb;
546 
547 		// during some PM-driven resume scenarios,
548 		// these (async) unlinks complete immediately
549 		retval = usb_unlink_urb (urb);
550 		if (retval != -EINPROGRESS && retval != 0)
551 			devdbg (dev, "unlink urb err, %d", retval);
552 		else
553 			count++;
554 	}
555 	spin_unlock_irqrestore (&q->lock, flags);
556 	return count;
557 }
558 
559 // Flush all pending rx urbs
560 // minidrivers may need to do this when the MTU changes
561 
562 void usbnet_unlink_rx_urbs(struct usbnet *dev)
563 {
564 	if (netif_running(dev->net)) {
565 		(void) unlink_urbs (dev, &dev->rxq);
566 		tasklet_schedule(&dev->bh);
567 	}
568 }
569 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
570 
571 /*-------------------------------------------------------------------------*/
572 
573 // precondition: never called in_interrupt
574 
575 int usbnet_stop (struct net_device *net)
576 {
577 	struct usbnet		*dev = netdev_priv(net);
578 	int			temp;
579 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK (unlink_wakeup);
580 	DECLARE_WAITQUEUE (wait, current);
581 
582 	netif_stop_queue (net);
583 
584 	if (netif_msg_ifdown (dev))
585 		devinfo (dev, "stop stats: rx/tx %ld/%ld, errs %ld/%ld",
586 			dev->stats.rx_packets, dev->stats.tx_packets,
587 			dev->stats.rx_errors, dev->stats.tx_errors
588 			);
589 
590 	// ensure there are no more active urbs
591 	add_wait_queue (&unlink_wakeup, &wait);
592 	dev->wait = &unlink_wakeup;
593 	temp = unlink_urbs (dev, &dev->txq) + unlink_urbs (dev, &dev->rxq);
594 
595 	// maybe wait for deletions to finish.
596 	while (!skb_queue_empty(&dev->rxq)
597 			&& !skb_queue_empty(&dev->txq)
598 			&& !skb_queue_empty(&dev->done)) {
599 		msleep(UNLINK_TIMEOUT_MS);
600 		if (netif_msg_ifdown (dev))
601 			devdbg (dev, "waited for %d urb completions", temp);
602 	}
603 	dev->wait = NULL;
604 	remove_wait_queue (&unlink_wakeup, &wait);
605 
606 	usb_kill_urb(dev->interrupt);
607 
608 	/* deferred work (task, timer, softirq) must also stop.
609 	 * can't flush_scheduled_work() until we drop rtnl (later),
610 	 * else workers could deadlock; so make workers a NOP.
611 	 */
612 	dev->flags = 0;
613 	del_timer_sync (&dev->delay);
614 	tasklet_kill (&dev->bh);
615 	usb_autopm_put_interface(dev->intf);
616 
617 	return 0;
618 }
619 EXPORT_SYMBOL_GPL(usbnet_stop);
620 
621 /*-------------------------------------------------------------------------*/
622 
623 // posts reads, and enables write queuing
624 
625 // precondition: never called in_interrupt
626 
627 int usbnet_open (struct net_device *net)
628 {
629 	struct usbnet		*dev = netdev_priv(net);
630 	int			retval;
631 	struct driver_info	*info = dev->driver_info;
632 
633 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
634 		if (netif_msg_ifup (dev))
635 			devinfo (dev,
636 				"resumption fail (%d) usbnet usb-%s-%s, %s",
637 				retval,
638 				dev->udev->bus->bus_name, dev->udev->devpath,
639 			info->description);
640 		goto done_nopm;
641 	}
642 
643 	// put into "known safe" state
644 	if (info->reset && (retval = info->reset (dev)) < 0) {
645 		if (netif_msg_ifup (dev))
646 			devinfo (dev,
647 				"open reset fail (%d) usbnet usb-%s-%s, %s",
648 				retval,
649 				dev->udev->bus->bus_name, dev->udev->devpath,
650 			info->description);
651 		goto done;
652 	}
653 
654 	// insist peer be connected
655 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
656 		if (netif_msg_ifup (dev))
657 			devdbg (dev, "can't open; %d", retval);
658 		goto done;
659 	}
660 
661 	/* start any status interrupt transfer */
662 	if (dev->interrupt) {
663 		retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
664 		if (retval < 0) {
665 			if (netif_msg_ifup (dev))
666 				deverr (dev, "intr submit %d", retval);
667 			goto done;
668 		}
669 	}
670 
671 	netif_start_queue (net);
672 	if (netif_msg_ifup (dev)) {
673 		char	*framing;
674 
675 		if (dev->driver_info->flags & FLAG_FRAMING_NC)
676 			framing = "NetChip";
677 		else if (dev->driver_info->flags & FLAG_FRAMING_GL)
678 			framing = "GeneSys";
679 		else if (dev->driver_info->flags & FLAG_FRAMING_Z)
680 			framing = "Zaurus";
681 		else if (dev->driver_info->flags & FLAG_FRAMING_RN)
682 			framing = "RNDIS";
683 		else if (dev->driver_info->flags & FLAG_FRAMING_AX)
684 			framing = "ASIX";
685 		else
686 			framing = "simple";
687 
688 		devinfo (dev, "open: enable queueing "
689 				"(rx %d, tx %d) mtu %d %s framing",
690 			(int)RX_QLEN (dev), (int)TX_QLEN (dev), dev->net->mtu,
691 			framing);
692 	}
693 
694 	// delay posting reads until we're fully open
695 	tasklet_schedule (&dev->bh);
696 	return retval;
697 done:
698 	usb_autopm_put_interface(dev->intf);
699 done_nopm:
700 	return retval;
701 }
702 EXPORT_SYMBOL_GPL(usbnet_open);
703 
704 /*-------------------------------------------------------------------------*/
705 
706 /* ethtool methods; minidrivers may need to add some more, but
707  * they'll probably want to use this base set.
708  */
709 
710 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
711 {
712 	struct usbnet *dev = netdev_priv(net);
713 
714 	if (!dev->mii.mdio_read)
715 		return -EOPNOTSUPP;
716 
717 	return mii_ethtool_gset(&dev->mii, cmd);
718 }
719 EXPORT_SYMBOL_GPL(usbnet_get_settings);
720 
721 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
722 {
723 	struct usbnet *dev = netdev_priv(net);
724 	int retval;
725 
726 	if (!dev->mii.mdio_write)
727 		return -EOPNOTSUPP;
728 
729 	retval = mii_ethtool_sset(&dev->mii, cmd);
730 
731 	/* link speed/duplex might have changed */
732 	if (dev->driver_info->link_reset)
733 		dev->driver_info->link_reset(dev);
734 
735 	return retval;
736 
737 }
738 EXPORT_SYMBOL_GPL(usbnet_set_settings);
739 
740 u32 usbnet_get_link (struct net_device *net)
741 {
742 	struct usbnet *dev = netdev_priv(net);
743 
744 	/* If a check_connect is defined, return its result */
745 	if (dev->driver_info->check_connect)
746 		return dev->driver_info->check_connect (dev) == 0;
747 
748 	/* if the device has mii operations, use those */
749 	if (dev->mii.mdio_read)
750 		return mii_link_ok(&dev->mii);
751 
752 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
753 	return ethtool_op_get_link(net);
754 }
755 EXPORT_SYMBOL_GPL(usbnet_get_link);
756 
757 int usbnet_nway_reset(struct net_device *net)
758 {
759 	struct usbnet *dev = netdev_priv(net);
760 
761 	if (!dev->mii.mdio_write)
762 		return -EOPNOTSUPP;
763 
764 	return mii_nway_restart(&dev->mii);
765 }
766 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
767 
768 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
769 {
770 	struct usbnet *dev = netdev_priv(net);
771 
772 	strncpy (info->driver, dev->driver_name, sizeof info->driver);
773 	strncpy (info->version, DRIVER_VERSION, sizeof info->version);
774 	strncpy (info->fw_version, dev->driver_info->description,
775 		sizeof info->fw_version);
776 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
777 }
778 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
779 
780 u32 usbnet_get_msglevel (struct net_device *net)
781 {
782 	struct usbnet *dev = netdev_priv(net);
783 
784 	return dev->msg_enable;
785 }
786 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
787 
788 void usbnet_set_msglevel (struct net_device *net, u32 level)
789 {
790 	struct usbnet *dev = netdev_priv(net);
791 
792 	dev->msg_enable = level;
793 }
794 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
795 
796 /* drivers may override default ethtool_ops in their bind() routine */
797 static struct ethtool_ops usbnet_ethtool_ops = {
798 	.get_settings		= usbnet_get_settings,
799 	.set_settings		= usbnet_set_settings,
800 	.get_link		= usbnet_get_link,
801 	.nway_reset		= usbnet_nway_reset,
802 	.get_drvinfo		= usbnet_get_drvinfo,
803 	.get_msglevel		= usbnet_get_msglevel,
804 	.set_msglevel		= usbnet_set_msglevel,
805 };
806 
807 /*-------------------------------------------------------------------------*/
808 
809 /* work that cannot be done in interrupt context uses keventd.
810  *
811  * NOTE:  with 2.5 we could do more of this using completion callbacks,
812  * especially now that control transfers can be queued.
813  */
814 static void
815 kevent (struct work_struct *work)
816 {
817 	struct usbnet		*dev =
818 		container_of(work, struct usbnet, kevent);
819 	int			status;
820 
821 	/* usb_clear_halt() needs a thread context */
822 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
823 		unlink_urbs (dev, &dev->txq);
824 		status = usb_clear_halt (dev->udev, dev->out);
825 		if (status < 0
826 				&& status != -EPIPE
827 				&& status != -ESHUTDOWN) {
828 			if (netif_msg_tx_err (dev))
829 				deverr (dev, "can't clear tx halt, status %d",
830 					status);
831 		} else {
832 			clear_bit (EVENT_TX_HALT, &dev->flags);
833 			if (status != -ESHUTDOWN)
834 				netif_wake_queue (dev->net);
835 		}
836 	}
837 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
838 		unlink_urbs (dev, &dev->rxq);
839 		status = usb_clear_halt (dev->udev, dev->in);
840 		if (status < 0
841 				&& status != -EPIPE
842 				&& status != -ESHUTDOWN) {
843 			if (netif_msg_rx_err (dev))
844 				deverr (dev, "can't clear rx halt, status %d",
845 					status);
846 		} else {
847 			clear_bit (EVENT_RX_HALT, &dev->flags);
848 			tasklet_schedule (&dev->bh);
849 		}
850 	}
851 
852 	/* tasklet could resubmit itself forever if memory is tight */
853 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
854 		struct urb	*urb = NULL;
855 
856 		if (netif_running (dev->net))
857 			urb = usb_alloc_urb (0, GFP_KERNEL);
858 		else
859 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
860 		if (urb != NULL) {
861 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
862 			rx_submit (dev, urb, GFP_KERNEL);
863 			tasklet_schedule (&dev->bh);
864 		}
865 	}
866 
867 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
868 		struct driver_info	*info = dev->driver_info;
869 		int			retval = 0;
870 
871 		clear_bit (EVENT_LINK_RESET, &dev->flags);
872 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
873 			devinfo(dev, "link reset failed (%d) usbnet usb-%s-%s, %s",
874 				retval,
875 				dev->udev->bus->bus_name, dev->udev->devpath,
876 				info->description);
877 		}
878 	}
879 
880 	if (dev->flags)
881 		devdbg (dev, "kevent done, flags = 0x%lx",
882 			dev->flags);
883 }
884 
885 /*-------------------------------------------------------------------------*/
886 
887 static void tx_complete (struct urb *urb)
888 {
889 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
890 	struct skb_data		*entry = (struct skb_data *) skb->cb;
891 	struct usbnet		*dev = entry->dev;
892 
893 	if (urb->status == 0) {
894 		dev->stats.tx_packets++;
895 		dev->stats.tx_bytes += entry->length;
896 	} else {
897 		dev->stats.tx_errors++;
898 
899 		switch (urb->status) {
900 		case -EPIPE:
901 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
902 			break;
903 
904 		/* software-driven interface shutdown */
905 		case -ECONNRESET:		// async unlink
906 		case -ESHUTDOWN:		// hardware gone
907 			break;
908 
909 		// like rx, tx gets controller i/o faults during khubd delays
910 		// and so it uses the same throttling mechanism.
911 		case -EPROTO:
912 		case -ETIME:
913 		case -EILSEQ:
914 			if (!timer_pending (&dev->delay)) {
915 				mod_timer (&dev->delay,
916 					jiffies + THROTTLE_JIFFIES);
917 				if (netif_msg_link (dev))
918 					devdbg (dev, "tx throttle %d",
919 							urb->status);
920 			}
921 			netif_stop_queue (dev->net);
922 			break;
923 		default:
924 			if (netif_msg_tx_err (dev))
925 				devdbg (dev, "tx err %d", entry->urb->status);
926 			break;
927 		}
928 	}
929 
930 	urb->dev = NULL;
931 	entry->state = tx_done;
932 	defer_bh(dev, skb, &dev->txq);
933 }
934 
935 /*-------------------------------------------------------------------------*/
936 
937 void usbnet_tx_timeout (struct net_device *net)
938 {
939 	struct usbnet		*dev = netdev_priv(net);
940 
941 	unlink_urbs (dev, &dev->txq);
942 	tasklet_schedule (&dev->bh);
943 
944 	// FIXME: device recovery -- reset?
945 }
946 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
947 
948 /*-------------------------------------------------------------------------*/
949 
950 int usbnet_start_xmit (struct sk_buff *skb, struct net_device *net)
951 {
952 	struct usbnet		*dev = netdev_priv(net);
953 	int			length;
954 	int			retval = NET_XMIT_SUCCESS;
955 	struct urb		*urb = NULL;
956 	struct skb_data		*entry;
957 	struct driver_info	*info = dev->driver_info;
958 	unsigned long		flags;
959 
960 	// some devices want funky USB-level framing, for
961 	// win32 driver (usually) and/or hardware quirks
962 	if (info->tx_fixup) {
963 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
964 		if (!skb) {
965 			if (netif_msg_tx_err (dev))
966 				devdbg (dev, "can't tx_fixup skb");
967 			goto drop;
968 		}
969 	}
970 	length = skb->len;
971 
972 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
973 		if (netif_msg_tx_err (dev))
974 			devdbg (dev, "no urb");
975 		goto drop;
976 	}
977 
978 	entry = (struct skb_data *) skb->cb;
979 	entry->urb = urb;
980 	entry->dev = dev;
981 	entry->state = tx_start;
982 	entry->length = length;
983 
984 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
985 			skb->data, skb->len, tx_complete, skb);
986 
987 	/* don't assume the hardware handles USB_ZERO_PACKET
988 	 * NOTE:  strictly conforming cdc-ether devices should expect
989 	 * the ZLP here, but ignore the one-byte packet.
990 	 */
991 	if ((length % dev->maxpacket) == 0) {
992 		urb->transfer_buffer_length++;
993 		if (skb_tailroom(skb)) {
994 			skb->data[skb->len] = 0;
995 			__skb_put(skb, 1);
996 		}
997 	}
998 
999 	spin_lock_irqsave (&dev->txq.lock, flags);
1000 
1001 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1002 	case -EPIPE:
1003 		netif_stop_queue (net);
1004 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1005 		break;
1006 	default:
1007 		if (netif_msg_tx_err (dev))
1008 			devdbg (dev, "tx: submit urb err %d", retval);
1009 		break;
1010 	case 0:
1011 		net->trans_start = jiffies;
1012 		__skb_queue_tail (&dev->txq, skb);
1013 		if (dev->txq.qlen >= TX_QLEN (dev))
1014 			netif_stop_queue (net);
1015 	}
1016 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1017 
1018 	if (retval) {
1019 		if (netif_msg_tx_err (dev))
1020 			devdbg (dev, "drop, code %d", retval);
1021 drop:
1022 		retval = NET_XMIT_SUCCESS;
1023 		dev->stats.tx_dropped++;
1024 		if (skb)
1025 			dev_kfree_skb_any (skb);
1026 		usb_free_urb (urb);
1027 	} else if (netif_msg_tx_queued (dev)) {
1028 		devdbg (dev, "> tx, len %d, type 0x%x",
1029 			length, skb->protocol);
1030 	}
1031 	return retval;
1032 }
1033 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1034 
1035 /*-------------------------------------------------------------------------*/
1036 
1037 // tasklet (work deferred from completions, in_irq) or timer
1038 
1039 static void usbnet_bh (unsigned long param)
1040 {
1041 	struct usbnet		*dev = (struct usbnet *) param;
1042 	struct sk_buff		*skb;
1043 	struct skb_data		*entry;
1044 
1045 	while ((skb = skb_dequeue (&dev->done))) {
1046 		entry = (struct skb_data *) skb->cb;
1047 		switch (entry->state) {
1048 		case rx_done:
1049 			entry->state = rx_cleanup;
1050 			rx_process (dev, skb);
1051 			continue;
1052 		case tx_done:
1053 		case rx_cleanup:
1054 			usb_free_urb (entry->urb);
1055 			dev_kfree_skb (skb);
1056 			continue;
1057 		default:
1058 			devdbg (dev, "bogus skb state %d", entry->state);
1059 		}
1060 	}
1061 
1062 	// waiting for all pending urbs to complete?
1063 	if (dev->wait) {
1064 		if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
1065 			wake_up (dev->wait);
1066 		}
1067 
1068 	// or are we maybe short a few urbs?
1069 	} else if (netif_running (dev->net)
1070 			&& netif_device_present (dev->net)
1071 			&& !timer_pending (&dev->delay)
1072 			&& !test_bit (EVENT_RX_HALT, &dev->flags)) {
1073 		int	temp = dev->rxq.qlen;
1074 		int	qlen = RX_QLEN (dev);
1075 
1076 		if (temp < qlen) {
1077 			struct urb	*urb;
1078 			int		i;
1079 
1080 			// don't refill the queue all at once
1081 			for (i = 0; i < 10 && dev->rxq.qlen < qlen; i++) {
1082 				urb = usb_alloc_urb (0, GFP_ATOMIC);
1083 				if (urb != NULL)
1084 					rx_submit (dev, urb, GFP_ATOMIC);
1085 			}
1086 			if (temp != dev->rxq.qlen && netif_msg_link (dev))
1087 				devdbg (dev, "rxqlen %d --> %d",
1088 						temp, dev->rxq.qlen);
1089 			if (dev->rxq.qlen < qlen)
1090 				tasklet_schedule (&dev->bh);
1091 		}
1092 		if (dev->txq.qlen < TX_QLEN (dev))
1093 			netif_wake_queue (dev->net);
1094 	}
1095 }
1096 
1097 
1098 
1099 /*-------------------------------------------------------------------------
1100  *
1101  * USB Device Driver support
1102  *
1103  *-------------------------------------------------------------------------*/
1104 
1105 // precondition: never called in_interrupt
1106 
1107 void usbnet_disconnect (struct usb_interface *intf)
1108 {
1109 	struct usbnet		*dev;
1110 	struct usb_device	*xdev;
1111 	struct net_device	*net;
1112 
1113 	dev = usb_get_intfdata(intf);
1114 	usb_set_intfdata(intf, NULL);
1115 	if (!dev)
1116 		return;
1117 
1118 	xdev = interface_to_usbdev (intf);
1119 
1120 	if (netif_msg_probe (dev))
1121 		devinfo (dev, "unregister '%s' usb-%s-%s, %s",
1122 			intf->dev.driver->name,
1123 			xdev->bus->bus_name, xdev->devpath,
1124 			dev->driver_info->description);
1125 
1126 	net = dev->net;
1127 	unregister_netdev (net);
1128 
1129 	/* we don't hold rtnl here ... */
1130 	flush_scheduled_work ();
1131 
1132 	if (dev->driver_info->unbind)
1133 		dev->driver_info->unbind (dev, intf);
1134 
1135 	free_netdev(net);
1136 	usb_put_dev (xdev);
1137 }
1138 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1139 
1140 static const struct net_device_ops usbnet_netdev_ops = {
1141 	.ndo_open		= usbnet_open,
1142 	.ndo_stop		= usbnet_stop,
1143 	.ndo_start_xmit		= usbnet_start_xmit,
1144 	.ndo_tx_timeout		= usbnet_tx_timeout,
1145 	.ndo_change_mtu		= usbnet_change_mtu,
1146 	.ndo_set_mac_address 	= eth_mac_addr,
1147 	.ndo_validate_addr	= eth_validate_addr,
1148 };
1149 
1150 /*-------------------------------------------------------------------------*/
1151 
1152 // precondition: never called in_interrupt
1153 
1154 int
1155 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1156 {
1157 	struct usbnet			*dev;
1158 	struct net_device		*net;
1159 	struct usb_host_interface	*interface;
1160 	struct driver_info		*info;
1161 	struct usb_device		*xdev;
1162 	int				status;
1163 	const char			*name;
1164 
1165 	name = udev->dev.driver->name;
1166 	info = (struct driver_info *) prod->driver_info;
1167 	if (!info) {
1168 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1169 		return -ENODEV;
1170 	}
1171 	xdev = interface_to_usbdev (udev);
1172 	interface = udev->cur_altsetting;
1173 
1174 	usb_get_dev (xdev);
1175 
1176 	status = -ENOMEM;
1177 
1178 	// set up our own records
1179 	net = alloc_etherdev(sizeof(*dev));
1180 	if (!net) {
1181 		dbg ("can't kmalloc dev");
1182 		goto out;
1183 	}
1184 
1185 	dev = netdev_priv(net);
1186 	dev->udev = xdev;
1187 	dev->intf = udev;
1188 	dev->driver_info = info;
1189 	dev->driver_name = name;
1190 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1191 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1192 	skb_queue_head_init (&dev->rxq);
1193 	skb_queue_head_init (&dev->txq);
1194 	skb_queue_head_init (&dev->done);
1195 	dev->bh.func = usbnet_bh;
1196 	dev->bh.data = (unsigned long) dev;
1197 	INIT_WORK (&dev->kevent, kevent);
1198 	dev->delay.function = usbnet_bh;
1199 	dev->delay.data = (unsigned long) dev;
1200 	init_timer (&dev->delay);
1201 	mutex_init (&dev->phy_mutex);
1202 
1203 	dev->net = net;
1204 	strcpy (net->name, "usb%d");
1205 	memcpy (net->dev_addr, node_id, sizeof node_id);
1206 
1207 	/* rx and tx sides can use different message sizes;
1208 	 * bind() should set rx_urb_size in that case.
1209 	 */
1210 	dev->hard_mtu = net->mtu + net->hard_header_len;
1211 #if 0
1212 // dma_supported() is deeply broken on almost all architectures
1213 	// possible with some EHCI controllers
1214 	if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1215 		net->features |= NETIF_F_HIGHDMA;
1216 #endif
1217 
1218 	net->netdev_ops = &usbnet_netdev_ops;
1219 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1220 	net->ethtool_ops = &usbnet_ethtool_ops;
1221 
1222 	// allow device-specific bind/init procedures
1223 	// NOTE net->name still not usable ...
1224 	if (info->bind) {
1225 		status = info->bind (dev, udev);
1226 		if (status < 0)
1227 			goto out1;
1228 
1229 		// heuristic:  "usb%d" for links we know are two-host,
1230 		// else "eth%d" when there's reasonable doubt.  userspace
1231 		// can rename the link if it knows better.
1232 		if ((dev->driver_info->flags & FLAG_ETHER) != 0
1233 				&& (net->dev_addr [0] & 0x02) == 0)
1234 			strcpy (net->name, "eth%d");
1235 		/* WLAN devices should always be named "wlan%d" */
1236 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1237 			strcpy(net->name, "wlan%d");
1238 
1239 		/* maybe the remote can't receive an Ethernet MTU */
1240 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1241 			net->mtu = dev->hard_mtu - net->hard_header_len;
1242 	} else if (!info->in || !info->out)
1243 		status = usbnet_get_endpoints (dev, udev);
1244 	else {
1245 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1246 		dev->out = usb_sndbulkpipe (xdev, info->out);
1247 		if (!(info->flags & FLAG_NO_SETINT))
1248 			status = usb_set_interface (xdev,
1249 				interface->desc.bInterfaceNumber,
1250 				interface->desc.bAlternateSetting);
1251 		else
1252 			status = 0;
1253 
1254 	}
1255 	if (status >= 0 && dev->status)
1256 		status = init_status (dev, udev);
1257 	if (status < 0)
1258 		goto out3;
1259 
1260 	if (!dev->rx_urb_size)
1261 		dev->rx_urb_size = dev->hard_mtu;
1262 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1263 
1264 	SET_NETDEV_DEV(net, &udev->dev);
1265 	status = register_netdev (net);
1266 	if (status)
1267 		goto out3;
1268 	if (netif_msg_probe (dev))
1269 		devinfo (dev, "register '%s' at usb-%s-%s, %s, %pM",
1270 			udev->dev.driver->name,
1271 			xdev->bus->bus_name, xdev->devpath,
1272 			dev->driver_info->description,
1273 			net->dev_addr);
1274 
1275 	// ok, it's ready to go.
1276 	usb_set_intfdata (udev, dev);
1277 
1278 	// start as if the link is up
1279 	netif_device_attach (net);
1280 
1281 	return 0;
1282 
1283 out3:
1284 	if (info->unbind)
1285 		info->unbind (dev, udev);
1286 out1:
1287 	free_netdev(net);
1288 out:
1289 	usb_put_dev(xdev);
1290 	return status;
1291 }
1292 EXPORT_SYMBOL_GPL(usbnet_probe);
1293 
1294 /*-------------------------------------------------------------------------*/
1295 
1296 /*
1297  * suspend the whole driver as soon as the first interface is suspended
1298  * resume only when the last interface is resumed
1299  */
1300 
1301 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1302 {
1303 	struct usbnet		*dev = usb_get_intfdata(intf);
1304 
1305 	if (!dev->suspend_count++) {
1306 		/*
1307 		 * accelerate emptying of the rx and queues, to avoid
1308 		 * having everything error out.
1309 		 */
1310 		netif_device_detach (dev->net);
1311 		(void) unlink_urbs (dev, &dev->rxq);
1312 		(void) unlink_urbs (dev, &dev->txq);
1313 		/*
1314 		 * reattach so runtime management can use and
1315 		 * wake the device
1316 		 */
1317 		netif_device_attach (dev->net);
1318 	}
1319 	return 0;
1320 }
1321 EXPORT_SYMBOL_GPL(usbnet_suspend);
1322 
1323 int usbnet_resume (struct usb_interface *intf)
1324 {
1325 	struct usbnet		*dev = usb_get_intfdata(intf);
1326 
1327 	if (!--dev->suspend_count)
1328 		tasklet_schedule (&dev->bh);
1329 
1330 	return 0;
1331 }
1332 EXPORT_SYMBOL_GPL(usbnet_resume);
1333 
1334 
1335 /*-------------------------------------------------------------------------*/
1336 
1337 static int __init usbnet_init(void)
1338 {
1339 	/* compiler should optimize this out */
1340 	BUILD_BUG_ON (sizeof (((struct sk_buff *)0)->cb)
1341 			< sizeof (struct skb_data));
1342 
1343 	random_ether_addr(node_id);
1344 	return 0;
1345 }
1346 module_init(usbnet_init);
1347 
1348 static void __exit usbnet_exit(void)
1349 {
1350 }
1351 module_exit(usbnet_exit);
1352 
1353 MODULE_AUTHOR("David Brownell");
1354 MODULE_DESCRIPTION("USB network driver framework");
1355 MODULE_LICENSE("GPL");
1356