xref: /linux/drivers/net/usb/usbnet.c (revision a33f32244d8550da8b4a26e277ce07d5c6d158b5)
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 #include <linux/slab.h>
47 
48 #define DRIVER_VERSION		"22-Aug-2005"
49 
50 
51 /*-------------------------------------------------------------------------*/
52 
53 /*
54  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
55  * Several dozen bytes of IPv4 data can fit in two such transactions.
56  * One maximum size Ethernet packet takes twenty four of them.
57  * For high speed, each frame comfortably fits almost 36 max size
58  * Ethernet packets (so queues should be bigger).
59  *
60  * REVISIT qlens should be members of 'struct usbnet'; the goal is to
61  * let the USB host controller be busy for 5msec or more before an irq
62  * is required, under load.  Jumbograms change the equation.
63  */
64 #define RX_MAX_QUEUE_MEMORY (60 * 1518)
65 #define	RX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
66 			(RX_MAX_QUEUE_MEMORY/(dev)->rx_urb_size) : 4)
67 #define	TX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
68 			(RX_MAX_QUEUE_MEMORY/(dev)->hard_mtu) : 4)
69 
70 // reawaken network queue this soon after stopping; else watchdog barks
71 #define TX_TIMEOUT_JIFFIES	(5*HZ)
72 
73 // throttle rx/tx briefly after some faults, so khubd might disconnect()
74 // us (it polls at HZ/4 usually) before we report too many false errors.
75 #define THROTTLE_JIFFIES	(HZ/8)
76 
77 // between wakeups
78 #define UNLINK_TIMEOUT_MS	3
79 
80 /*-------------------------------------------------------------------------*/
81 
82 // randomly generated ethernet address
83 static u8	node_id [ETH_ALEN];
84 
85 static const char driver_name [] = "usbnet";
86 
87 /* use ethtool to change the level for any given device */
88 static int msg_level = -1;
89 module_param (msg_level, int, 0);
90 MODULE_PARM_DESC (msg_level, "Override default message level");
91 
92 /*-------------------------------------------------------------------------*/
93 
94 /* handles CDC Ethernet and many other network "bulk data" interfaces */
95 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
96 {
97 	int				tmp;
98 	struct usb_host_interface	*alt = NULL;
99 	struct usb_host_endpoint	*in = NULL, *out = NULL;
100 	struct usb_host_endpoint	*status = NULL;
101 
102 	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
103 		unsigned	ep;
104 
105 		in = out = status = NULL;
106 		alt = intf->altsetting + tmp;
107 
108 		/* take the first altsetting with in-bulk + out-bulk;
109 		 * remember any status endpoint, just in case;
110 		 * ignore other endpoints and altsetttings.
111 		 */
112 		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
113 			struct usb_host_endpoint	*e;
114 			int				intr = 0;
115 
116 			e = alt->endpoint + ep;
117 			switch (e->desc.bmAttributes) {
118 			case USB_ENDPOINT_XFER_INT:
119 				if (!usb_endpoint_dir_in(&e->desc))
120 					continue;
121 				intr = 1;
122 				/* FALLTHROUGH */
123 			case USB_ENDPOINT_XFER_BULK:
124 				break;
125 			default:
126 				continue;
127 			}
128 			if (usb_endpoint_dir_in(&e->desc)) {
129 				if (!intr && !in)
130 					in = e;
131 				else if (intr && !status)
132 					status = e;
133 			} else {
134 				if (!out)
135 					out = e;
136 			}
137 		}
138 		if (in && out)
139 			break;
140 	}
141 	if (!alt || !in || !out)
142 		return -EINVAL;
143 
144 	if (alt->desc.bAlternateSetting != 0 ||
145 	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
146 		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
147 				alt->desc.bAlternateSetting);
148 		if (tmp < 0)
149 			return tmp;
150 	}
151 
152 	dev->in = usb_rcvbulkpipe (dev->udev,
153 			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
154 	dev->out = usb_sndbulkpipe (dev->udev,
155 			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
156 	dev->status = status;
157 	return 0;
158 }
159 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
160 
161 static u8 nibble(unsigned char c)
162 {
163 	if (likely(isdigit(c)))
164 		return c - '0';
165 	c = toupper(c);
166 	if (likely(isxdigit(c)))
167 		return 10 + c - 'A';
168 	return 0;
169 }
170 
171 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
172 {
173 	int 		tmp, i;
174 	unsigned char	buf [13];
175 
176 	tmp = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
177 	if (tmp != 12) {
178 		dev_dbg(&dev->udev->dev,
179 			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
180 		if (tmp >= 0)
181 			tmp = -EINVAL;
182 		return tmp;
183 	}
184 	for (i = tmp = 0; i < 6; i++, tmp += 2)
185 		dev->net->dev_addr [i] =
186 			(nibble(buf [tmp]) << 4) + nibble(buf [tmp + 1]);
187 	return 0;
188 }
189 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
190 
191 static void intr_complete (struct urb *urb);
192 
193 static int init_status (struct usbnet *dev, struct usb_interface *intf)
194 {
195 	char		*buf = NULL;
196 	unsigned	pipe = 0;
197 	unsigned	maxp;
198 	unsigned	period;
199 
200 	if (!dev->driver_info->status)
201 		return 0;
202 
203 	pipe = usb_rcvintpipe (dev->udev,
204 			dev->status->desc.bEndpointAddress
205 				& USB_ENDPOINT_NUMBER_MASK);
206 	maxp = usb_maxpacket (dev->udev, pipe, 0);
207 
208 	/* avoid 1 msec chatter:  min 8 msec poll rate */
209 	period = max ((int) dev->status->desc.bInterval,
210 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
211 
212 	buf = kmalloc (maxp, GFP_KERNEL);
213 	if (buf) {
214 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
215 		if (!dev->interrupt) {
216 			kfree (buf);
217 			return -ENOMEM;
218 		} else {
219 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
220 				buf, maxp, intr_complete, dev, period);
221 			dev_dbg(&intf->dev,
222 				"status ep%din, %d bytes period %d\n",
223 				usb_pipeendpoint(pipe), maxp, period);
224 		}
225 	}
226 	return 0;
227 }
228 
229 /* Passes this packet up the stack, updating its accounting.
230  * Some link protocols batch packets, so their rx_fixup paths
231  * can return clones as well as just modify the original skb.
232  */
233 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
234 {
235 	int	status;
236 
237 	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
238 		skb_queue_tail(&dev->rxq_pause, skb);
239 		return;
240 	}
241 
242 	skb->protocol = eth_type_trans (skb, dev->net);
243 	dev->net->stats.rx_packets++;
244 	dev->net->stats.rx_bytes += skb->len;
245 
246 	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
247 		  skb->len + sizeof (struct ethhdr), skb->protocol);
248 	memset (skb->cb, 0, sizeof (struct skb_data));
249 	status = netif_rx (skb);
250 	if (status != NET_RX_SUCCESS)
251 		netif_dbg(dev, rx_err, dev->net,
252 			  "netif_rx status %d\n", status);
253 }
254 EXPORT_SYMBOL_GPL(usbnet_skb_return);
255 
256 
257 /*-------------------------------------------------------------------------
258  *
259  * Network Device Driver (peer link to "Host Device", from USB host)
260  *
261  *-------------------------------------------------------------------------*/
262 
263 int usbnet_change_mtu (struct net_device *net, int new_mtu)
264 {
265 	struct usbnet	*dev = netdev_priv(net);
266 	int		ll_mtu = new_mtu + net->hard_header_len;
267 	int		old_hard_mtu = dev->hard_mtu;
268 	int		old_rx_urb_size = dev->rx_urb_size;
269 
270 	if (new_mtu <= 0)
271 		return -EINVAL;
272 	// no second zero-length packet read wanted after mtu-sized packets
273 	if ((ll_mtu % dev->maxpacket) == 0)
274 		return -EDOM;
275 	net->mtu = new_mtu;
276 
277 	dev->hard_mtu = net->mtu + net->hard_header_len;
278 	if (dev->rx_urb_size == old_hard_mtu) {
279 		dev->rx_urb_size = dev->hard_mtu;
280 		if (dev->rx_urb_size > old_rx_urb_size)
281 			usbnet_unlink_rx_urbs(dev);
282 	}
283 
284 	return 0;
285 }
286 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
287 
288 /*-------------------------------------------------------------------------*/
289 
290 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
291  * completion callbacks.  2.5 should have fixed those bugs...
292  */
293 
294 static void defer_bh(struct usbnet *dev, struct sk_buff *skb, struct sk_buff_head *list)
295 {
296 	unsigned long		flags;
297 
298 	spin_lock_irqsave(&list->lock, flags);
299 	__skb_unlink(skb, list);
300 	spin_unlock(&list->lock);
301 	spin_lock(&dev->done.lock);
302 	__skb_queue_tail(&dev->done, skb);
303 	if (dev->done.qlen == 1)
304 		tasklet_schedule(&dev->bh);
305 	spin_unlock_irqrestore(&dev->done.lock, flags);
306 }
307 
308 /* some work can't be done in tasklets, so we use keventd
309  *
310  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
311  * but tasklet_schedule() doesn't.  hope the failure is rare.
312  */
313 void usbnet_defer_kevent (struct usbnet *dev, int work)
314 {
315 	set_bit (work, &dev->flags);
316 	if (!schedule_work (&dev->kevent))
317 		netdev_err(dev->net, "kevent %d may have been dropped\n", work);
318 	else
319 		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
320 }
321 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
322 
323 /*-------------------------------------------------------------------------*/
324 
325 static void rx_complete (struct urb *urb);
326 
327 static void rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
328 {
329 	struct sk_buff		*skb;
330 	struct skb_data		*entry;
331 	int			retval = 0;
332 	unsigned long		lockflags;
333 	size_t			size = dev->rx_urb_size;
334 
335 	if ((skb = alloc_skb (size + NET_IP_ALIGN, flags)) == NULL) {
336 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
337 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
338 		usb_free_urb (urb);
339 		return;
340 	}
341 	skb_reserve (skb, NET_IP_ALIGN);
342 
343 	entry = (struct skb_data *) skb->cb;
344 	entry->urb = urb;
345 	entry->dev = dev;
346 	entry->state = rx_start;
347 	entry->length = 0;
348 
349 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
350 		skb->data, size, rx_complete, skb);
351 
352 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
353 
354 	if (netif_running (dev->net) &&
355 	    netif_device_present (dev->net) &&
356 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
357 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
358 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
359 		case -EPIPE:
360 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
361 			break;
362 		case -ENOMEM:
363 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
364 			break;
365 		case -ENODEV:
366 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
367 			netif_device_detach (dev->net);
368 			break;
369 		default:
370 			netif_dbg(dev, rx_err, dev->net,
371 				  "rx submit, %d\n", retval);
372 			tasklet_schedule (&dev->bh);
373 			break;
374 		case 0:
375 			__skb_queue_tail (&dev->rxq, skb);
376 		}
377 	} else {
378 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
379 		retval = -ENOLINK;
380 	}
381 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
382 	if (retval) {
383 		dev_kfree_skb_any (skb);
384 		usb_free_urb (urb);
385 	}
386 }
387 
388 
389 /*-------------------------------------------------------------------------*/
390 
391 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
392 {
393 	if (dev->driver_info->rx_fixup &&
394 	    !dev->driver_info->rx_fixup (dev, skb))
395 		goto error;
396 	// else network stack removes extra byte if we forced a short packet
397 
398 	if (skb->len)
399 		usbnet_skb_return (dev, skb);
400 	else {
401 		netif_dbg(dev, rx_err, dev->net, "drop\n");
402 error:
403 		dev->net->stats.rx_errors++;
404 		skb_queue_tail (&dev->done, skb);
405 	}
406 }
407 
408 /*-------------------------------------------------------------------------*/
409 
410 static void rx_complete (struct urb *urb)
411 {
412 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
413 	struct skb_data		*entry = (struct skb_data *) skb->cb;
414 	struct usbnet		*dev = entry->dev;
415 	int			urb_status = urb->status;
416 
417 	skb_put (skb, urb->actual_length);
418 	entry->state = rx_done;
419 	entry->urb = NULL;
420 
421 	switch (urb_status) {
422 	/* success */
423 	case 0:
424 		if (skb->len < dev->net->hard_header_len) {
425 			entry->state = rx_cleanup;
426 			dev->net->stats.rx_errors++;
427 			dev->net->stats.rx_length_errors++;
428 			netif_dbg(dev, rx_err, dev->net,
429 				  "rx length %d\n", skb->len);
430 		}
431 		break;
432 
433 	/* stalls need manual reset. this is rare ... except that
434 	 * when going through USB 2.0 TTs, unplug appears this way.
435 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
436 	 * storm, recovering as needed.
437 	 */
438 	case -EPIPE:
439 		dev->net->stats.rx_errors++;
440 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
441 		// FALLTHROUGH
442 
443 	/* software-driven interface shutdown */
444 	case -ECONNRESET:		/* async unlink */
445 	case -ESHUTDOWN:		/* hardware gone */
446 		netif_dbg(dev, ifdown, dev->net,
447 			  "rx shutdown, code %d\n", urb_status);
448 		goto block;
449 
450 	/* we get controller i/o faults during khubd disconnect() delays.
451 	 * throttle down resubmits, to avoid log floods; just temporarily,
452 	 * so we still recover when the fault isn't a khubd delay.
453 	 */
454 	case -EPROTO:
455 	case -ETIME:
456 	case -EILSEQ:
457 		dev->net->stats.rx_errors++;
458 		if (!timer_pending (&dev->delay)) {
459 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
460 			netif_dbg(dev, link, dev->net,
461 				  "rx throttle %d\n", urb_status);
462 		}
463 block:
464 		entry->state = rx_cleanup;
465 		entry->urb = urb;
466 		urb = NULL;
467 		break;
468 
469 	/* data overrun ... flush fifo? */
470 	case -EOVERFLOW:
471 		dev->net->stats.rx_over_errors++;
472 		// FALLTHROUGH
473 
474 	default:
475 		entry->state = rx_cleanup;
476 		dev->net->stats.rx_errors++;
477 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
478 		break;
479 	}
480 
481 	defer_bh(dev, skb, &dev->rxq);
482 
483 	if (urb) {
484 		if (netif_running (dev->net) &&
485 		    !test_bit (EVENT_RX_HALT, &dev->flags)) {
486 			rx_submit (dev, urb, GFP_ATOMIC);
487 			return;
488 		}
489 		usb_free_urb (urb);
490 	}
491 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
492 }
493 
494 static void intr_complete (struct urb *urb)
495 {
496 	struct usbnet	*dev = urb->context;
497 	int		status = urb->status;
498 
499 	switch (status) {
500 	/* success */
501 	case 0:
502 		dev->driver_info->status(dev, urb);
503 		break;
504 
505 	/* software-driven interface shutdown */
506 	case -ENOENT:		/* urb killed */
507 	case -ESHUTDOWN:	/* hardware gone */
508 		netif_dbg(dev, ifdown, dev->net,
509 			  "intr shutdown, code %d\n", status);
510 		return;
511 
512 	/* NOTE:  not throttling like RX/TX, since this endpoint
513 	 * already polls infrequently
514 	 */
515 	default:
516 		netdev_dbg(dev->net, "intr status %d\n", status);
517 		break;
518 	}
519 
520 	if (!netif_running (dev->net))
521 		return;
522 
523 	memset(urb->transfer_buffer, 0, urb->transfer_buffer_length);
524 	status = usb_submit_urb (urb, GFP_ATOMIC);
525 	if (status != 0)
526 		netif_err(dev, timer, dev->net,
527 			  "intr resubmit --> %d\n", status);
528 }
529 
530 /*-------------------------------------------------------------------------*/
531 void usbnet_pause_rx(struct usbnet *dev)
532 {
533 	set_bit(EVENT_RX_PAUSED, &dev->flags);
534 
535 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
536 }
537 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
538 
539 void usbnet_resume_rx(struct usbnet *dev)
540 {
541 	struct sk_buff *skb;
542 	int num = 0;
543 
544 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
545 
546 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
547 		usbnet_skb_return(dev, skb);
548 		num++;
549 	}
550 
551 	tasklet_schedule(&dev->bh);
552 
553 	netif_dbg(dev, rx_status, dev->net,
554 		  "paused rx queue disabled, %d skbs requeued\n", num);
555 }
556 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
557 
558 void usbnet_purge_paused_rxq(struct usbnet *dev)
559 {
560 	skb_queue_purge(&dev->rxq_pause);
561 }
562 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
563 
564 /*-------------------------------------------------------------------------*/
565 
566 // unlink pending rx/tx; completion handlers do all other cleanup
567 
568 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
569 {
570 	unsigned long		flags;
571 	struct sk_buff		*skb, *skbnext;
572 	int			count = 0;
573 
574 	spin_lock_irqsave (&q->lock, flags);
575 	skb_queue_walk_safe(q, skb, skbnext) {
576 		struct skb_data		*entry;
577 		struct urb		*urb;
578 		int			retval;
579 
580 		entry = (struct skb_data *) skb->cb;
581 		urb = entry->urb;
582 
583 		// during some PM-driven resume scenarios,
584 		// these (async) unlinks complete immediately
585 		retval = usb_unlink_urb (urb);
586 		if (retval != -EINPROGRESS && retval != 0)
587 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
588 		else
589 			count++;
590 	}
591 	spin_unlock_irqrestore (&q->lock, flags);
592 	return count;
593 }
594 
595 // Flush all pending rx urbs
596 // minidrivers may need to do this when the MTU changes
597 
598 void usbnet_unlink_rx_urbs(struct usbnet *dev)
599 {
600 	if (netif_running(dev->net)) {
601 		(void) unlink_urbs (dev, &dev->rxq);
602 		tasklet_schedule(&dev->bh);
603 	}
604 }
605 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
606 
607 /*-------------------------------------------------------------------------*/
608 
609 // precondition: never called in_interrupt
610 static void usbnet_terminate_urbs(struct usbnet *dev)
611 {
612 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
613 	DECLARE_WAITQUEUE(wait, current);
614 	int temp;
615 
616 	/* ensure there are no more active urbs */
617 	add_wait_queue(&unlink_wakeup, &wait);
618 	set_current_state(TASK_UNINTERRUPTIBLE);
619 	dev->wait = &unlink_wakeup;
620 	temp = unlink_urbs(dev, &dev->txq) +
621 		unlink_urbs(dev, &dev->rxq);
622 
623 	/* maybe wait for deletions to finish. */
624 	while (!skb_queue_empty(&dev->rxq)
625 		&& !skb_queue_empty(&dev->txq)
626 		&& !skb_queue_empty(&dev->done)) {
627 			schedule_timeout(UNLINK_TIMEOUT_MS);
628 			set_current_state(TASK_UNINTERRUPTIBLE);
629 			netif_dbg(dev, ifdown, dev->net,
630 				  "waited for %d urb completions\n", temp);
631 	}
632 	set_current_state(TASK_RUNNING);
633 	dev->wait = NULL;
634 	remove_wait_queue(&unlink_wakeup, &wait);
635 }
636 
637 int usbnet_stop (struct net_device *net)
638 {
639 	struct usbnet		*dev = netdev_priv(net);
640 	struct driver_info	*info = dev->driver_info;
641 	int			retval;
642 
643 	netif_stop_queue (net);
644 
645 	netif_info(dev, ifdown, dev->net,
646 		   "stop stats: rx/tx %ld/%ld, errs %ld/%ld\n",
647 		   net->stats.rx_packets, net->stats.tx_packets,
648 		   net->stats.rx_errors, net->stats.tx_errors);
649 
650 	/* allow minidriver to stop correctly (wireless devices to turn off
651 	 * radio etc) */
652 	if (info->stop) {
653 		retval = info->stop(dev);
654 		if (retval < 0)
655 			netif_info(dev, ifdown, dev->net,
656 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
657 				   retval,
658 				   dev->udev->bus->bus_name, dev->udev->devpath,
659 				   info->description);
660 	}
661 
662 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
663 		usbnet_terminate_urbs(dev);
664 
665 	usb_kill_urb(dev->interrupt);
666 
667 	usbnet_purge_paused_rxq(dev);
668 
669 	/* deferred work (task, timer, softirq) must also stop.
670 	 * can't flush_scheduled_work() until we drop rtnl (later),
671 	 * else workers could deadlock; so make workers a NOP.
672 	 */
673 	dev->flags = 0;
674 	del_timer_sync (&dev->delay);
675 	tasklet_kill (&dev->bh);
676 	if (info->manage_power)
677 		info->manage_power(dev, 0);
678 	else
679 		usb_autopm_put_interface(dev->intf);
680 
681 	return 0;
682 }
683 EXPORT_SYMBOL_GPL(usbnet_stop);
684 
685 /*-------------------------------------------------------------------------*/
686 
687 // posts reads, and enables write queuing
688 
689 // precondition: never called in_interrupt
690 
691 int usbnet_open (struct net_device *net)
692 {
693 	struct usbnet		*dev = netdev_priv(net);
694 	int			retval;
695 	struct driver_info	*info = dev->driver_info;
696 
697 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
698 		netif_info(dev, ifup, dev->net,
699 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
700 			   retval,
701 			   dev->udev->bus->bus_name,
702 			   dev->udev->devpath,
703 			   info->description);
704 		goto done_nopm;
705 	}
706 
707 	// put into "known safe" state
708 	if (info->reset && (retval = info->reset (dev)) < 0) {
709 		netif_info(dev, ifup, dev->net,
710 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
711 			   retval,
712 			   dev->udev->bus->bus_name,
713 			   dev->udev->devpath,
714 			   info->description);
715 		goto done;
716 	}
717 
718 	// insist peer be connected
719 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
720 		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
721 		goto done;
722 	}
723 
724 	/* start any status interrupt transfer */
725 	if (dev->interrupt) {
726 		retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
727 		if (retval < 0) {
728 			netif_err(dev, ifup, dev->net,
729 				  "intr submit %d\n", retval);
730 			goto done;
731 		}
732 	}
733 
734 	netif_start_queue (net);
735 	netif_info(dev, ifup, dev->net,
736 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
737 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
738 		   dev->net->mtu,
739 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
740 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
741 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
742 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
743 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
744 		   "simple");
745 
746 	// delay posting reads until we're fully open
747 	tasklet_schedule (&dev->bh);
748 	if (info->manage_power) {
749 		retval = info->manage_power(dev, 1);
750 		if (retval < 0)
751 			goto done;
752 		usb_autopm_put_interface(dev->intf);
753 	}
754 	return retval;
755 
756 done:
757 	usb_autopm_put_interface(dev->intf);
758 done_nopm:
759 	return retval;
760 }
761 EXPORT_SYMBOL_GPL(usbnet_open);
762 
763 /*-------------------------------------------------------------------------*/
764 
765 /* ethtool methods; minidrivers may need to add some more, but
766  * they'll probably want to use this base set.
767  */
768 
769 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
770 {
771 	struct usbnet *dev = netdev_priv(net);
772 
773 	if (!dev->mii.mdio_read)
774 		return -EOPNOTSUPP;
775 
776 	return mii_ethtool_gset(&dev->mii, cmd);
777 }
778 EXPORT_SYMBOL_GPL(usbnet_get_settings);
779 
780 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
781 {
782 	struct usbnet *dev = netdev_priv(net);
783 	int retval;
784 
785 	if (!dev->mii.mdio_write)
786 		return -EOPNOTSUPP;
787 
788 	retval = mii_ethtool_sset(&dev->mii, cmd);
789 
790 	/* link speed/duplex might have changed */
791 	if (dev->driver_info->link_reset)
792 		dev->driver_info->link_reset(dev);
793 
794 	return retval;
795 
796 }
797 EXPORT_SYMBOL_GPL(usbnet_set_settings);
798 
799 u32 usbnet_get_link (struct net_device *net)
800 {
801 	struct usbnet *dev = netdev_priv(net);
802 
803 	/* If a check_connect is defined, return its result */
804 	if (dev->driver_info->check_connect)
805 		return dev->driver_info->check_connect (dev) == 0;
806 
807 	/* if the device has mii operations, use those */
808 	if (dev->mii.mdio_read)
809 		return mii_link_ok(&dev->mii);
810 
811 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
812 	return ethtool_op_get_link(net);
813 }
814 EXPORT_SYMBOL_GPL(usbnet_get_link);
815 
816 int usbnet_nway_reset(struct net_device *net)
817 {
818 	struct usbnet *dev = netdev_priv(net);
819 
820 	if (!dev->mii.mdio_write)
821 		return -EOPNOTSUPP;
822 
823 	return mii_nway_restart(&dev->mii);
824 }
825 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
826 
827 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
828 {
829 	struct usbnet *dev = netdev_priv(net);
830 
831 	strncpy (info->driver, dev->driver_name, sizeof info->driver);
832 	strncpy (info->version, DRIVER_VERSION, sizeof info->version);
833 	strncpy (info->fw_version, dev->driver_info->description,
834 		sizeof info->fw_version);
835 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
836 }
837 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
838 
839 u32 usbnet_get_msglevel (struct net_device *net)
840 {
841 	struct usbnet *dev = netdev_priv(net);
842 
843 	return dev->msg_enable;
844 }
845 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
846 
847 void usbnet_set_msglevel (struct net_device *net, u32 level)
848 {
849 	struct usbnet *dev = netdev_priv(net);
850 
851 	dev->msg_enable = level;
852 }
853 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
854 
855 /* drivers may override default ethtool_ops in their bind() routine */
856 static const struct ethtool_ops usbnet_ethtool_ops = {
857 	.get_settings		= usbnet_get_settings,
858 	.set_settings		= usbnet_set_settings,
859 	.get_link		= usbnet_get_link,
860 	.nway_reset		= usbnet_nway_reset,
861 	.get_drvinfo		= usbnet_get_drvinfo,
862 	.get_msglevel		= usbnet_get_msglevel,
863 	.set_msglevel		= usbnet_set_msglevel,
864 };
865 
866 /*-------------------------------------------------------------------------*/
867 
868 /* work that cannot be done in interrupt context uses keventd.
869  *
870  * NOTE:  with 2.5 we could do more of this using completion callbacks,
871  * especially now that control transfers can be queued.
872  */
873 static void
874 kevent (struct work_struct *work)
875 {
876 	struct usbnet		*dev =
877 		container_of(work, struct usbnet, kevent);
878 	int			status;
879 
880 	/* usb_clear_halt() needs a thread context */
881 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
882 		unlink_urbs (dev, &dev->txq);
883 		status = usb_autopm_get_interface(dev->intf);
884 		if (status < 0)
885 			goto fail_pipe;
886 		status = usb_clear_halt (dev->udev, dev->out);
887 		usb_autopm_put_interface(dev->intf);
888 		if (status < 0 &&
889 		    status != -EPIPE &&
890 		    status != -ESHUTDOWN) {
891 			if (netif_msg_tx_err (dev))
892 fail_pipe:
893 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
894 					   status);
895 		} else {
896 			clear_bit (EVENT_TX_HALT, &dev->flags);
897 			if (status != -ESHUTDOWN)
898 				netif_wake_queue (dev->net);
899 		}
900 	}
901 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
902 		unlink_urbs (dev, &dev->rxq);
903 		status = usb_autopm_get_interface(dev->intf);
904 		if (status < 0)
905 			goto fail_halt;
906 		status = usb_clear_halt (dev->udev, dev->in);
907 		usb_autopm_put_interface(dev->intf);
908 		if (status < 0 &&
909 		    status != -EPIPE &&
910 		    status != -ESHUTDOWN) {
911 			if (netif_msg_rx_err (dev))
912 fail_halt:
913 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
914 					   status);
915 		} else {
916 			clear_bit (EVENT_RX_HALT, &dev->flags);
917 			tasklet_schedule (&dev->bh);
918 		}
919 	}
920 
921 	/* tasklet could resubmit itself forever if memory is tight */
922 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
923 		struct urb	*urb = NULL;
924 
925 		if (netif_running (dev->net))
926 			urb = usb_alloc_urb (0, GFP_KERNEL);
927 		else
928 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
929 		if (urb != NULL) {
930 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
931 			status = usb_autopm_get_interface(dev->intf);
932 			if (status < 0)
933 				goto fail_lowmem;
934 			rx_submit (dev, urb, GFP_KERNEL);
935 			usb_autopm_put_interface(dev->intf);
936 fail_lowmem:
937 			tasklet_schedule (&dev->bh);
938 		}
939 	}
940 
941 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
942 		struct driver_info	*info = dev->driver_info;
943 		int			retval = 0;
944 
945 		clear_bit (EVENT_LINK_RESET, &dev->flags);
946 		status = usb_autopm_get_interface(dev->intf);
947 		if (status < 0)
948 			goto skip_reset;
949 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
950 			usb_autopm_put_interface(dev->intf);
951 skip_reset:
952 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
953 				    retval,
954 				    dev->udev->bus->bus_name,
955 				    dev->udev->devpath,
956 				    info->description);
957 		} else {
958 			usb_autopm_put_interface(dev->intf);
959 		}
960 	}
961 
962 	if (dev->flags)
963 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
964 }
965 
966 /*-------------------------------------------------------------------------*/
967 
968 static void tx_complete (struct urb *urb)
969 {
970 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
971 	struct skb_data		*entry = (struct skb_data *) skb->cb;
972 	struct usbnet		*dev = entry->dev;
973 
974 	if (urb->status == 0) {
975 		dev->net->stats.tx_packets++;
976 		dev->net->stats.tx_bytes += entry->length;
977 	} else {
978 		dev->net->stats.tx_errors++;
979 
980 		switch (urb->status) {
981 		case -EPIPE:
982 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
983 			break;
984 
985 		/* software-driven interface shutdown */
986 		case -ECONNRESET:		// async unlink
987 		case -ESHUTDOWN:		// hardware gone
988 			break;
989 
990 		// like rx, tx gets controller i/o faults during khubd delays
991 		// and so it uses the same throttling mechanism.
992 		case -EPROTO:
993 		case -ETIME:
994 		case -EILSEQ:
995 			usb_mark_last_busy(dev->udev);
996 			if (!timer_pending (&dev->delay)) {
997 				mod_timer (&dev->delay,
998 					jiffies + THROTTLE_JIFFIES);
999 				netif_dbg(dev, link, dev->net,
1000 					  "tx throttle %d\n", urb->status);
1001 			}
1002 			netif_stop_queue (dev->net);
1003 			break;
1004 		default:
1005 			netif_dbg(dev, tx_err, dev->net,
1006 				  "tx err %d\n", entry->urb->status);
1007 			break;
1008 		}
1009 	}
1010 
1011 	usb_autopm_put_interface_async(dev->intf);
1012 	urb->dev = NULL;
1013 	entry->state = tx_done;
1014 	defer_bh(dev, skb, &dev->txq);
1015 }
1016 
1017 /*-------------------------------------------------------------------------*/
1018 
1019 void usbnet_tx_timeout (struct net_device *net)
1020 {
1021 	struct usbnet		*dev = netdev_priv(net);
1022 
1023 	unlink_urbs (dev, &dev->txq);
1024 	tasklet_schedule (&dev->bh);
1025 
1026 	// FIXME: device recovery -- reset?
1027 }
1028 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1029 
1030 /*-------------------------------------------------------------------------*/
1031 
1032 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1033 				     struct net_device *net)
1034 {
1035 	struct usbnet		*dev = netdev_priv(net);
1036 	int			length;
1037 	struct urb		*urb = NULL;
1038 	struct skb_data		*entry;
1039 	struct driver_info	*info = dev->driver_info;
1040 	unsigned long		flags;
1041 	int retval;
1042 
1043 	// some devices want funky USB-level framing, for
1044 	// win32 driver (usually) and/or hardware quirks
1045 	if (info->tx_fixup) {
1046 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1047 		if (!skb) {
1048 			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1049 			goto drop;
1050 		}
1051 	}
1052 	length = skb->len;
1053 
1054 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1055 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1056 		goto drop;
1057 	}
1058 
1059 	entry = (struct skb_data *) skb->cb;
1060 	entry->urb = urb;
1061 	entry->dev = dev;
1062 	entry->state = tx_start;
1063 	entry->length = length;
1064 
1065 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1066 			skb->data, skb->len, tx_complete, skb);
1067 
1068 	/* don't assume the hardware handles USB_ZERO_PACKET
1069 	 * NOTE:  strictly conforming cdc-ether devices should expect
1070 	 * the ZLP here, but ignore the one-byte packet.
1071 	 */
1072 	if (!(info->flags & FLAG_SEND_ZLP) && (length % dev->maxpacket) == 0) {
1073 		urb->transfer_buffer_length++;
1074 		if (skb_tailroom(skb)) {
1075 			skb->data[skb->len] = 0;
1076 			__skb_put(skb, 1);
1077 		}
1078 	}
1079 
1080 	spin_lock_irqsave(&dev->txq.lock, flags);
1081 	retval = usb_autopm_get_interface_async(dev->intf);
1082 	if (retval < 0) {
1083 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1084 		goto drop;
1085 	}
1086 
1087 #ifdef CONFIG_PM
1088 	/* if this triggers the device is still a sleep */
1089 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1090 		/* transmission will be done in resume */
1091 		usb_anchor_urb(urb, &dev->deferred);
1092 		/* no use to process more packets */
1093 		netif_stop_queue(net);
1094 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1095 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1096 		goto deferred;
1097 	}
1098 #endif
1099 
1100 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1101 	case -EPIPE:
1102 		netif_stop_queue (net);
1103 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1104 		usb_autopm_put_interface_async(dev->intf);
1105 		break;
1106 	default:
1107 		usb_autopm_put_interface_async(dev->intf);
1108 		netif_dbg(dev, tx_err, dev->net,
1109 			  "tx: submit urb err %d\n", retval);
1110 		break;
1111 	case 0:
1112 		net->trans_start = jiffies;
1113 		__skb_queue_tail (&dev->txq, skb);
1114 		if (dev->txq.qlen >= TX_QLEN (dev))
1115 			netif_stop_queue (net);
1116 	}
1117 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1118 
1119 	if (retval) {
1120 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1121 drop:
1122 		dev->net->stats.tx_dropped++;
1123 		if (skb)
1124 			dev_kfree_skb_any (skb);
1125 		usb_free_urb (urb);
1126 	} else
1127 		netif_dbg(dev, tx_queued, dev->net,
1128 			  "> tx, len %d, type 0x%x\n", length, skb->protocol);
1129 #ifdef CONFIG_PM
1130 deferred:
1131 #endif
1132 	return NETDEV_TX_OK;
1133 }
1134 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1135 
1136 /*-------------------------------------------------------------------------*/
1137 
1138 // tasklet (work deferred from completions, in_irq) or timer
1139 
1140 static void usbnet_bh (unsigned long param)
1141 {
1142 	struct usbnet		*dev = (struct usbnet *) param;
1143 	struct sk_buff		*skb;
1144 	struct skb_data		*entry;
1145 
1146 	while ((skb = skb_dequeue (&dev->done))) {
1147 		entry = (struct skb_data *) skb->cb;
1148 		switch (entry->state) {
1149 		case rx_done:
1150 			entry->state = rx_cleanup;
1151 			rx_process (dev, skb);
1152 			continue;
1153 		case tx_done:
1154 		case rx_cleanup:
1155 			usb_free_urb (entry->urb);
1156 			dev_kfree_skb (skb);
1157 			continue;
1158 		default:
1159 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1160 		}
1161 	}
1162 
1163 	// waiting for all pending urbs to complete?
1164 	if (dev->wait) {
1165 		if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
1166 			wake_up (dev->wait);
1167 		}
1168 
1169 	// or are we maybe short a few urbs?
1170 	} else if (netif_running (dev->net) &&
1171 		   netif_device_present (dev->net) &&
1172 		   !timer_pending (&dev->delay) &&
1173 		   !test_bit (EVENT_RX_HALT, &dev->flags)) {
1174 		int	temp = dev->rxq.qlen;
1175 		int	qlen = RX_QLEN (dev);
1176 
1177 		if (temp < qlen) {
1178 			struct urb	*urb;
1179 			int		i;
1180 
1181 			// don't refill the queue all at once
1182 			for (i = 0; i < 10 && dev->rxq.qlen < qlen; i++) {
1183 				urb = usb_alloc_urb (0, GFP_ATOMIC);
1184 				if (urb != NULL)
1185 					rx_submit (dev, urb, GFP_ATOMIC);
1186 			}
1187 			if (temp != dev->rxq.qlen)
1188 				netif_dbg(dev, link, dev->net,
1189 					  "rxqlen %d --> %d\n",
1190 					  temp, dev->rxq.qlen);
1191 			if (dev->rxq.qlen < qlen)
1192 				tasklet_schedule (&dev->bh);
1193 		}
1194 		if (dev->txq.qlen < TX_QLEN (dev))
1195 			netif_wake_queue (dev->net);
1196 	}
1197 }
1198 
1199 
1200 /*-------------------------------------------------------------------------
1201  *
1202  * USB Device Driver support
1203  *
1204  *-------------------------------------------------------------------------*/
1205 
1206 // precondition: never called in_interrupt
1207 
1208 void usbnet_disconnect (struct usb_interface *intf)
1209 {
1210 	struct usbnet		*dev;
1211 	struct usb_device	*xdev;
1212 	struct net_device	*net;
1213 
1214 	dev = usb_get_intfdata(intf);
1215 	usb_set_intfdata(intf, NULL);
1216 	if (!dev)
1217 		return;
1218 
1219 	xdev = interface_to_usbdev (intf);
1220 
1221 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1222 		   intf->dev.driver->name,
1223 		   xdev->bus->bus_name, xdev->devpath,
1224 		   dev->driver_info->description);
1225 
1226 	net = dev->net;
1227 	unregister_netdev (net);
1228 
1229 	/* we don't hold rtnl here ... */
1230 	flush_scheduled_work ();
1231 
1232 	if (dev->driver_info->unbind)
1233 		dev->driver_info->unbind (dev, intf);
1234 
1235 	free_netdev(net);
1236 	usb_put_dev (xdev);
1237 }
1238 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1239 
1240 static const struct net_device_ops usbnet_netdev_ops = {
1241 	.ndo_open		= usbnet_open,
1242 	.ndo_stop		= usbnet_stop,
1243 	.ndo_start_xmit		= usbnet_start_xmit,
1244 	.ndo_tx_timeout		= usbnet_tx_timeout,
1245 	.ndo_change_mtu		= usbnet_change_mtu,
1246 	.ndo_set_mac_address 	= eth_mac_addr,
1247 	.ndo_validate_addr	= eth_validate_addr,
1248 };
1249 
1250 /*-------------------------------------------------------------------------*/
1251 
1252 // precondition: never called in_interrupt
1253 
1254 static struct device_type wlan_type = {
1255 	.name	= "wlan",
1256 };
1257 
1258 static struct device_type wwan_type = {
1259 	.name	= "wwan",
1260 };
1261 
1262 int
1263 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1264 {
1265 	struct usbnet			*dev;
1266 	struct net_device		*net;
1267 	struct usb_host_interface	*interface;
1268 	struct driver_info		*info;
1269 	struct usb_device		*xdev;
1270 	int				status;
1271 	const char			*name;
1272 
1273 	name = udev->dev.driver->name;
1274 	info = (struct driver_info *) prod->driver_info;
1275 	if (!info) {
1276 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1277 		return -ENODEV;
1278 	}
1279 	xdev = interface_to_usbdev (udev);
1280 	interface = udev->cur_altsetting;
1281 
1282 	usb_get_dev (xdev);
1283 
1284 	status = -ENOMEM;
1285 
1286 	// set up our own records
1287 	net = alloc_etherdev(sizeof(*dev));
1288 	if (!net) {
1289 		dbg ("can't kmalloc dev");
1290 		goto out;
1291 	}
1292 
1293 	dev = netdev_priv(net);
1294 	dev->udev = xdev;
1295 	dev->intf = udev;
1296 	dev->driver_info = info;
1297 	dev->driver_name = name;
1298 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1299 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1300 	skb_queue_head_init (&dev->rxq);
1301 	skb_queue_head_init (&dev->txq);
1302 	skb_queue_head_init (&dev->done);
1303 	skb_queue_head_init(&dev->rxq_pause);
1304 	dev->bh.func = usbnet_bh;
1305 	dev->bh.data = (unsigned long) dev;
1306 	INIT_WORK (&dev->kevent, kevent);
1307 	init_usb_anchor(&dev->deferred);
1308 	dev->delay.function = usbnet_bh;
1309 	dev->delay.data = (unsigned long) dev;
1310 	init_timer (&dev->delay);
1311 	mutex_init (&dev->phy_mutex);
1312 
1313 	dev->net = net;
1314 	strcpy (net->name, "usb%d");
1315 	memcpy (net->dev_addr, node_id, sizeof node_id);
1316 
1317 	/* rx and tx sides can use different message sizes;
1318 	 * bind() should set rx_urb_size in that case.
1319 	 */
1320 	dev->hard_mtu = net->mtu + net->hard_header_len;
1321 #if 0
1322 // dma_supported() is deeply broken on almost all architectures
1323 	// possible with some EHCI controllers
1324 	if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1325 		net->features |= NETIF_F_HIGHDMA;
1326 #endif
1327 
1328 	net->netdev_ops = &usbnet_netdev_ops;
1329 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1330 	net->ethtool_ops = &usbnet_ethtool_ops;
1331 
1332 	// allow device-specific bind/init procedures
1333 	// NOTE net->name still not usable ...
1334 	if (info->bind) {
1335 		status = info->bind (dev, udev);
1336 		if (status < 0)
1337 			goto out1;
1338 
1339 		// heuristic:  "usb%d" for links we know are two-host,
1340 		// else "eth%d" when there's reasonable doubt.  userspace
1341 		// can rename the link if it knows better.
1342 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1343 		    (net->dev_addr [0] & 0x02) == 0)
1344 			strcpy (net->name, "eth%d");
1345 		/* WLAN devices should always be named "wlan%d" */
1346 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1347 			strcpy(net->name, "wlan%d");
1348 		/* WWAN devices should always be named "wwan%d" */
1349 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1350 			strcpy(net->name, "wwan%d");
1351 
1352 		/* maybe the remote can't receive an Ethernet MTU */
1353 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1354 			net->mtu = dev->hard_mtu - net->hard_header_len;
1355 	} else if (!info->in || !info->out)
1356 		status = usbnet_get_endpoints (dev, udev);
1357 	else {
1358 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1359 		dev->out = usb_sndbulkpipe (xdev, info->out);
1360 		if (!(info->flags & FLAG_NO_SETINT))
1361 			status = usb_set_interface (xdev,
1362 				interface->desc.bInterfaceNumber,
1363 				interface->desc.bAlternateSetting);
1364 		else
1365 			status = 0;
1366 
1367 	}
1368 	if (status >= 0 && dev->status)
1369 		status = init_status (dev, udev);
1370 	if (status < 0)
1371 		goto out3;
1372 
1373 	if (!dev->rx_urb_size)
1374 		dev->rx_urb_size = dev->hard_mtu;
1375 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1376 
1377 	SET_NETDEV_DEV(net, &udev->dev);
1378 
1379 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1380 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1381 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1382 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1383 
1384 	status = register_netdev (net);
1385 	if (status)
1386 		goto out3;
1387 	netif_info(dev, probe, dev->net,
1388 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1389 		   udev->dev.driver->name,
1390 		   xdev->bus->bus_name, xdev->devpath,
1391 		   dev->driver_info->description,
1392 		   net->dev_addr);
1393 
1394 	// ok, it's ready to go.
1395 	usb_set_intfdata (udev, dev);
1396 
1397 	netif_device_attach (net);
1398 
1399 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1400 		netif_carrier_off(net);
1401 
1402 	return 0;
1403 
1404 out3:
1405 	if (info->unbind)
1406 		info->unbind (dev, udev);
1407 out1:
1408 	free_netdev(net);
1409 out:
1410 	usb_put_dev(xdev);
1411 	return status;
1412 }
1413 EXPORT_SYMBOL_GPL(usbnet_probe);
1414 
1415 /*-------------------------------------------------------------------------*/
1416 
1417 /*
1418  * suspend the whole driver as soon as the first interface is suspended
1419  * resume only when the last interface is resumed
1420  */
1421 
1422 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1423 {
1424 	struct usbnet		*dev = usb_get_intfdata(intf);
1425 
1426 	if (!dev->suspend_count++) {
1427 		spin_lock_irq(&dev->txq.lock);
1428 		/* don't autosuspend while transmitting */
1429 		if (dev->txq.qlen && (message.event & PM_EVENT_AUTO)) {
1430 			spin_unlock_irq(&dev->txq.lock);
1431 			return -EBUSY;
1432 		} else {
1433 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1434 			spin_unlock_irq(&dev->txq.lock);
1435 		}
1436 		/*
1437 		 * accelerate emptying of the rx and queues, to avoid
1438 		 * having everything error out.
1439 		 */
1440 		netif_device_detach (dev->net);
1441 		usbnet_terminate_urbs(dev);
1442 		usb_kill_urb(dev->interrupt);
1443 
1444 		/*
1445 		 * reattach so runtime management can use and
1446 		 * wake the device
1447 		 */
1448 		netif_device_attach (dev->net);
1449 	}
1450 	return 0;
1451 }
1452 EXPORT_SYMBOL_GPL(usbnet_suspend);
1453 
1454 int usbnet_resume (struct usb_interface *intf)
1455 {
1456 	struct usbnet		*dev = usb_get_intfdata(intf);
1457 	struct sk_buff          *skb;
1458 	struct urb              *res;
1459 	int                     retval;
1460 
1461 	if (!--dev->suspend_count) {
1462 		spin_lock_irq(&dev->txq.lock);
1463 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1464 
1465 			printk(KERN_INFO"%s has delayed data\n", __func__);
1466 			skb = (struct sk_buff *)res->context;
1467 			retval = usb_submit_urb(res, GFP_ATOMIC);
1468 			if (retval < 0) {
1469 				dev_kfree_skb_any(skb);
1470 				usb_free_urb(res);
1471 				usb_autopm_put_interface_async(dev->intf);
1472 			} else {
1473 				dev->net->trans_start = jiffies;
1474 				__skb_queue_tail(&dev->txq, skb);
1475 			}
1476 		}
1477 
1478 		smp_mb();
1479 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1480 		spin_unlock_irq(&dev->txq.lock);
1481 		if (!(dev->txq.qlen >= TX_QLEN(dev)))
1482 			netif_start_queue(dev->net);
1483 		tasklet_schedule (&dev->bh);
1484 	}
1485 	return 0;
1486 }
1487 EXPORT_SYMBOL_GPL(usbnet_resume);
1488 
1489 
1490 /*-------------------------------------------------------------------------*/
1491 
1492 static int __init usbnet_init(void)
1493 {
1494 	/* compiler should optimize this out */
1495 	BUILD_BUG_ON (sizeof (((struct sk_buff *)0)->cb)
1496 			< sizeof (struct skb_data));
1497 
1498 	random_ether_addr(node_id);
1499 	return 0;
1500 }
1501 module_init(usbnet_init);
1502 
1503 static void __exit usbnet_exit(void)
1504 {
1505 }
1506 module_exit(usbnet_exit);
1507 
1508 MODULE_AUTHOR("David Brownell");
1509 MODULE_DESCRIPTION("USB network driver framework");
1510 MODULE_LICENSE("GPL");
1511