xref: /openbmc/linux/drivers/net/usb/usbnet.c (revision b0786b430c982dffbb44d8030e6b6088671ce745)
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 #include <linux/kernel.h>
48 #include <linux/pm_runtime.h>
49 
50 #define DRIVER_VERSION		"22-Aug-2005"
51 
52 
53 /*-------------------------------------------------------------------------*/
54 
55 /*
56  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
57  * Several dozen bytes of IPv4 data can fit in two such transactions.
58  * One maximum size Ethernet packet takes twenty four of them.
59  * For high speed, each frame comfortably fits almost 36 max size
60  * Ethernet packets (so queues should be bigger).
61  *
62  * REVISIT qlens should be members of 'struct usbnet'; the goal is to
63  * let the USB host controller be busy for 5msec or more before an irq
64  * is required, under load.  Jumbograms change the equation.
65  */
66 #define RX_MAX_QUEUE_MEMORY (60 * 1518)
67 #define	RX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
68 			(RX_MAX_QUEUE_MEMORY/(dev)->rx_urb_size) : 4)
69 #define	TX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
70 			(RX_MAX_QUEUE_MEMORY/(dev)->hard_mtu) : 4)
71 
72 // reawaken network queue this soon after stopping; else watchdog barks
73 #define TX_TIMEOUT_JIFFIES	(5*HZ)
74 
75 // throttle rx/tx briefly after some faults, so khubd might disconnect()
76 // us (it polls at HZ/4 usually) before we report too many false errors.
77 #define THROTTLE_JIFFIES	(HZ/8)
78 
79 // between wakeups
80 #define UNLINK_TIMEOUT_MS	3
81 
82 /*-------------------------------------------------------------------------*/
83 
84 // randomly generated ethernet address
85 static u8	node_id [ETH_ALEN];
86 
87 static const char driver_name [] = "usbnet";
88 
89 /* use ethtool to change the level for any given device */
90 static int msg_level = -1;
91 module_param (msg_level, int, 0);
92 MODULE_PARM_DESC (msg_level, "Override default message level");
93 
94 /*-------------------------------------------------------------------------*/
95 
96 /* handles CDC Ethernet and many other network "bulk data" interfaces */
97 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
98 {
99 	int				tmp;
100 	struct usb_host_interface	*alt = NULL;
101 	struct usb_host_endpoint	*in = NULL, *out = NULL;
102 	struct usb_host_endpoint	*status = NULL;
103 
104 	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
105 		unsigned	ep;
106 
107 		in = out = status = NULL;
108 		alt = intf->altsetting + tmp;
109 
110 		/* take the first altsetting with in-bulk + out-bulk;
111 		 * remember any status endpoint, just in case;
112 		 * ignore other endpoints and altsetttings.
113 		 */
114 		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
115 			struct usb_host_endpoint	*e;
116 			int				intr = 0;
117 
118 			e = alt->endpoint + ep;
119 			switch (e->desc.bmAttributes) {
120 			case USB_ENDPOINT_XFER_INT:
121 				if (!usb_endpoint_dir_in(&e->desc))
122 					continue;
123 				intr = 1;
124 				/* FALLTHROUGH */
125 			case USB_ENDPOINT_XFER_BULK:
126 				break;
127 			default:
128 				continue;
129 			}
130 			if (usb_endpoint_dir_in(&e->desc)) {
131 				if (!intr && !in)
132 					in = e;
133 				else if (intr && !status)
134 					status = e;
135 			} else {
136 				if (!out)
137 					out = e;
138 			}
139 		}
140 		if (in && out)
141 			break;
142 	}
143 	if (!alt || !in || !out)
144 		return -EINVAL;
145 
146 	if (alt->desc.bAlternateSetting != 0 ||
147 	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
148 		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
149 				alt->desc.bAlternateSetting);
150 		if (tmp < 0)
151 			return tmp;
152 	}
153 
154 	dev->in = usb_rcvbulkpipe (dev->udev,
155 			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
156 	dev->out = usb_sndbulkpipe (dev->udev,
157 			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
158 	dev->status = status;
159 	return 0;
160 }
161 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
162 
163 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
164 {
165 	int 		tmp, i;
166 	unsigned char	buf [13];
167 
168 	tmp = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
169 	if (tmp != 12) {
170 		dev_dbg(&dev->udev->dev,
171 			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
172 		if (tmp >= 0)
173 			tmp = -EINVAL;
174 		return tmp;
175 	}
176 	for (i = tmp = 0; i < 6; i++, tmp += 2)
177 		dev->net->dev_addr [i] =
178 			(hex_to_bin(buf[tmp]) << 4) + hex_to_bin(buf[tmp + 1]);
179 	return 0;
180 }
181 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
182 
183 static void intr_complete (struct urb *urb);
184 
185 static int init_status (struct usbnet *dev, struct usb_interface *intf)
186 {
187 	char		*buf = NULL;
188 	unsigned	pipe = 0;
189 	unsigned	maxp;
190 	unsigned	period;
191 
192 	if (!dev->driver_info->status)
193 		return 0;
194 
195 	pipe = usb_rcvintpipe (dev->udev,
196 			dev->status->desc.bEndpointAddress
197 				& USB_ENDPOINT_NUMBER_MASK);
198 	maxp = usb_maxpacket (dev->udev, pipe, 0);
199 
200 	/* avoid 1 msec chatter:  min 8 msec poll rate */
201 	period = max ((int) dev->status->desc.bInterval,
202 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
203 
204 	buf = kmalloc (maxp, GFP_KERNEL);
205 	if (buf) {
206 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
207 		if (!dev->interrupt) {
208 			kfree (buf);
209 			return -ENOMEM;
210 		} else {
211 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
212 				buf, maxp, intr_complete, dev, period);
213 			dev_dbg(&intf->dev,
214 				"status ep%din, %d bytes period %d\n",
215 				usb_pipeendpoint(pipe), maxp, period);
216 		}
217 	}
218 	return 0;
219 }
220 
221 /* Passes this packet up the stack, updating its accounting.
222  * Some link protocols batch packets, so their rx_fixup paths
223  * can return clones as well as just modify the original skb.
224  */
225 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
226 {
227 	int	status;
228 
229 	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
230 		skb_queue_tail(&dev->rxq_pause, skb);
231 		return;
232 	}
233 
234 	skb->protocol = eth_type_trans (skb, dev->net);
235 	dev->net->stats.rx_packets++;
236 	dev->net->stats.rx_bytes += skb->len;
237 
238 	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
239 		  skb->len + sizeof (struct ethhdr), skb->protocol);
240 	memset (skb->cb, 0, sizeof (struct skb_data));
241 	status = netif_rx (skb);
242 	if (status != NET_RX_SUCCESS)
243 		netif_dbg(dev, rx_err, dev->net,
244 			  "netif_rx status %d\n", status);
245 }
246 EXPORT_SYMBOL_GPL(usbnet_skb_return);
247 
248 
249 /*-------------------------------------------------------------------------
250  *
251  * Network Device Driver (peer link to "Host Device", from USB host)
252  *
253  *-------------------------------------------------------------------------*/
254 
255 int usbnet_change_mtu (struct net_device *net, int new_mtu)
256 {
257 	struct usbnet	*dev = netdev_priv(net);
258 	int		ll_mtu = new_mtu + net->hard_header_len;
259 	int		old_hard_mtu = dev->hard_mtu;
260 	int		old_rx_urb_size = dev->rx_urb_size;
261 
262 	if (new_mtu <= 0)
263 		return -EINVAL;
264 	// no second zero-length packet read wanted after mtu-sized packets
265 	if ((ll_mtu % dev->maxpacket) == 0)
266 		return -EDOM;
267 	net->mtu = new_mtu;
268 
269 	dev->hard_mtu = net->mtu + net->hard_header_len;
270 	if (dev->rx_urb_size == old_hard_mtu) {
271 		dev->rx_urb_size = dev->hard_mtu;
272 		if (dev->rx_urb_size > old_rx_urb_size)
273 			usbnet_unlink_rx_urbs(dev);
274 	}
275 
276 	return 0;
277 }
278 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
279 
280 /*-------------------------------------------------------------------------*/
281 
282 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
283  * completion callbacks.  2.5 should have fixed those bugs...
284  */
285 
286 static void defer_bh(struct usbnet *dev, struct sk_buff *skb, struct sk_buff_head *list)
287 {
288 	unsigned long		flags;
289 
290 	spin_lock_irqsave(&list->lock, flags);
291 	__skb_unlink(skb, list);
292 	spin_unlock(&list->lock);
293 	spin_lock(&dev->done.lock);
294 	__skb_queue_tail(&dev->done, skb);
295 	if (dev->done.qlen == 1)
296 		tasklet_schedule(&dev->bh);
297 	spin_unlock_irqrestore(&dev->done.lock, flags);
298 }
299 
300 /* some work can't be done in tasklets, so we use keventd
301  *
302  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
303  * but tasklet_schedule() doesn't.  hope the failure is rare.
304  */
305 void usbnet_defer_kevent (struct usbnet *dev, int work)
306 {
307 	set_bit (work, &dev->flags);
308 	if (!schedule_work (&dev->kevent))
309 		netdev_err(dev->net, "kevent %d may have been dropped\n", work);
310 	else
311 		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
312 }
313 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
314 
315 /*-------------------------------------------------------------------------*/
316 
317 static void rx_complete (struct urb *urb);
318 
319 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
320 {
321 	struct sk_buff		*skb;
322 	struct skb_data		*entry;
323 	int			retval = 0;
324 	unsigned long		lockflags;
325 	size_t			size = dev->rx_urb_size;
326 
327 	if ((skb = alloc_skb (size + NET_IP_ALIGN, flags)) == NULL) {
328 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
329 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
330 		usb_free_urb (urb);
331 		return -ENOMEM;
332 	}
333 	skb_reserve (skb, NET_IP_ALIGN);
334 
335 	entry = (struct skb_data *) skb->cb;
336 	entry->urb = urb;
337 	entry->dev = dev;
338 	entry->state = rx_start;
339 	entry->length = 0;
340 
341 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
342 		skb->data, size, rx_complete, skb);
343 
344 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
345 
346 	if (netif_running (dev->net) &&
347 	    netif_device_present (dev->net) &&
348 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
349 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
350 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
351 		case -EPIPE:
352 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
353 			break;
354 		case -ENOMEM:
355 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
356 			break;
357 		case -ENODEV:
358 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
359 			netif_device_detach (dev->net);
360 			break;
361 		case -EHOSTUNREACH:
362 			retval = -ENOLINK;
363 			break;
364 		default:
365 			netif_dbg(dev, rx_err, dev->net,
366 				  "rx submit, %d\n", retval);
367 			tasklet_schedule (&dev->bh);
368 			break;
369 		case 0:
370 			__skb_queue_tail (&dev->rxq, skb);
371 		}
372 	} else {
373 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
374 		retval = -ENOLINK;
375 	}
376 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
377 	if (retval) {
378 		dev_kfree_skb_any (skb);
379 		usb_free_urb (urb);
380 	}
381 	return retval;
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 		netif_dbg(dev, rx_err, dev->net, "drop\n");
398 error:
399 		dev->net->stats.rx_errors++;
400 		skb_queue_tail (&dev->done, skb);
401 	}
402 }
403 
404 /*-------------------------------------------------------------------------*/
405 
406 static void rx_complete (struct urb *urb)
407 {
408 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
409 	struct skb_data		*entry = (struct skb_data *) skb->cb;
410 	struct usbnet		*dev = entry->dev;
411 	int			urb_status = urb->status;
412 
413 	skb_put (skb, urb->actual_length);
414 	entry->state = rx_done;
415 	entry->urb = NULL;
416 
417 	switch (urb_status) {
418 	/* success */
419 	case 0:
420 		if (skb->len < dev->net->hard_header_len) {
421 			entry->state = rx_cleanup;
422 			dev->net->stats.rx_errors++;
423 			dev->net->stats.rx_length_errors++;
424 			netif_dbg(dev, rx_err, dev->net,
425 				  "rx length %d\n", skb->len);
426 		}
427 		break;
428 
429 	/* stalls need manual reset. this is rare ... except that
430 	 * when going through USB 2.0 TTs, unplug appears this way.
431 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
432 	 * storm, recovering as needed.
433 	 */
434 	case -EPIPE:
435 		dev->net->stats.rx_errors++;
436 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
437 		// FALLTHROUGH
438 
439 	/* software-driven interface shutdown */
440 	case -ECONNRESET:		/* async unlink */
441 	case -ESHUTDOWN:		/* hardware gone */
442 		netif_dbg(dev, ifdown, dev->net,
443 			  "rx shutdown, code %d\n", urb_status);
444 		goto block;
445 
446 	/* we get controller i/o faults during khubd disconnect() delays.
447 	 * throttle down resubmits, to avoid log floods; just temporarily,
448 	 * so we still recover when the fault isn't a khubd delay.
449 	 */
450 	case -EPROTO:
451 	case -ETIME:
452 	case -EILSEQ:
453 		dev->net->stats.rx_errors++;
454 		if (!timer_pending (&dev->delay)) {
455 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
456 			netif_dbg(dev, link, dev->net,
457 				  "rx throttle %d\n", urb_status);
458 		}
459 block:
460 		entry->state = rx_cleanup;
461 		entry->urb = urb;
462 		urb = NULL;
463 		break;
464 
465 	/* data overrun ... flush fifo? */
466 	case -EOVERFLOW:
467 		dev->net->stats.rx_over_errors++;
468 		// FALLTHROUGH
469 
470 	default:
471 		entry->state = rx_cleanup;
472 		dev->net->stats.rx_errors++;
473 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
474 		break;
475 	}
476 
477 	defer_bh(dev, skb, &dev->rxq);
478 
479 	if (urb) {
480 		if (netif_running (dev->net) &&
481 		    !test_bit (EVENT_RX_HALT, &dev->flags)) {
482 			rx_submit (dev, urb, GFP_ATOMIC);
483 			return;
484 		}
485 		usb_free_urb (urb);
486 	}
487 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
488 }
489 
490 static void intr_complete (struct urb *urb)
491 {
492 	struct usbnet	*dev = urb->context;
493 	int		status = urb->status;
494 
495 	switch (status) {
496 	/* success */
497 	case 0:
498 		dev->driver_info->status(dev, urb);
499 		break;
500 
501 	/* software-driven interface shutdown */
502 	case -ENOENT:		/* urb killed */
503 	case -ESHUTDOWN:	/* hardware gone */
504 		netif_dbg(dev, ifdown, dev->net,
505 			  "intr shutdown, code %d\n", status);
506 		return;
507 
508 	/* NOTE:  not throttling like RX/TX, since this endpoint
509 	 * already polls infrequently
510 	 */
511 	default:
512 		netdev_dbg(dev->net, "intr status %d\n", status);
513 		break;
514 	}
515 
516 	if (!netif_running (dev->net))
517 		return;
518 
519 	memset(urb->transfer_buffer, 0, urb->transfer_buffer_length);
520 	status = usb_submit_urb (urb, GFP_ATOMIC);
521 	if (status != 0)
522 		netif_err(dev, timer, dev->net,
523 			  "intr resubmit --> %d\n", status);
524 }
525 
526 /*-------------------------------------------------------------------------*/
527 void usbnet_pause_rx(struct usbnet *dev)
528 {
529 	set_bit(EVENT_RX_PAUSED, &dev->flags);
530 
531 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
532 }
533 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
534 
535 void usbnet_resume_rx(struct usbnet *dev)
536 {
537 	struct sk_buff *skb;
538 	int num = 0;
539 
540 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
541 
542 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
543 		usbnet_skb_return(dev, skb);
544 		num++;
545 	}
546 
547 	tasklet_schedule(&dev->bh);
548 
549 	netif_dbg(dev, rx_status, dev->net,
550 		  "paused rx queue disabled, %d skbs requeued\n", num);
551 }
552 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
553 
554 void usbnet_purge_paused_rxq(struct usbnet *dev)
555 {
556 	skb_queue_purge(&dev->rxq_pause);
557 }
558 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
559 
560 /*-------------------------------------------------------------------------*/
561 
562 // unlink pending rx/tx; completion handlers do all other cleanup
563 
564 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
565 {
566 	unsigned long		flags;
567 	struct sk_buff		*skb, *skbnext;
568 	int			count = 0;
569 
570 	spin_lock_irqsave (&q->lock, flags);
571 	skb_queue_walk_safe(q, skb, skbnext) {
572 		struct skb_data		*entry;
573 		struct urb		*urb;
574 		int			retval;
575 
576 		entry = (struct skb_data *) skb->cb;
577 		urb = entry->urb;
578 
579 		// during some PM-driven resume scenarios,
580 		// these (async) unlinks complete immediately
581 		retval = usb_unlink_urb (urb);
582 		if (retval != -EINPROGRESS && retval != 0)
583 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
584 		else
585 			count++;
586 	}
587 	spin_unlock_irqrestore (&q->lock, flags);
588 	return count;
589 }
590 
591 // Flush all pending rx urbs
592 // minidrivers may need to do this when the MTU changes
593 
594 void usbnet_unlink_rx_urbs(struct usbnet *dev)
595 {
596 	if (netif_running(dev->net)) {
597 		(void) unlink_urbs (dev, &dev->rxq);
598 		tasklet_schedule(&dev->bh);
599 	}
600 }
601 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
602 
603 /*-------------------------------------------------------------------------*/
604 
605 // precondition: never called in_interrupt
606 static void usbnet_terminate_urbs(struct usbnet *dev)
607 {
608 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
609 	DECLARE_WAITQUEUE(wait, current);
610 	int temp;
611 
612 	/* ensure there are no more active urbs */
613 	add_wait_queue(&unlink_wakeup, &wait);
614 	set_current_state(TASK_UNINTERRUPTIBLE);
615 	dev->wait = &unlink_wakeup;
616 	temp = unlink_urbs(dev, &dev->txq) +
617 		unlink_urbs(dev, &dev->rxq);
618 
619 	/* maybe wait for deletions to finish. */
620 	while (!skb_queue_empty(&dev->rxq)
621 		&& !skb_queue_empty(&dev->txq)
622 		&& !skb_queue_empty(&dev->done)) {
623 			schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
624 			set_current_state(TASK_UNINTERRUPTIBLE);
625 			netif_dbg(dev, ifdown, dev->net,
626 				  "waited for %d urb completions\n", temp);
627 	}
628 	set_current_state(TASK_RUNNING);
629 	dev->wait = NULL;
630 	remove_wait_queue(&unlink_wakeup, &wait);
631 }
632 
633 int usbnet_stop (struct net_device *net)
634 {
635 	struct usbnet		*dev = netdev_priv(net);
636 	struct driver_info	*info = dev->driver_info;
637 	int			retval;
638 
639 	netif_stop_queue (net);
640 
641 	netif_info(dev, ifdown, dev->net,
642 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
643 		   net->stats.rx_packets, net->stats.tx_packets,
644 		   net->stats.rx_errors, net->stats.tx_errors);
645 
646 	/* allow minidriver to stop correctly (wireless devices to turn off
647 	 * radio etc) */
648 	if (info->stop) {
649 		retval = info->stop(dev);
650 		if (retval < 0)
651 			netif_info(dev, ifdown, dev->net,
652 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
653 				   retval,
654 				   dev->udev->bus->bus_name, dev->udev->devpath,
655 				   info->description);
656 	}
657 
658 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
659 		usbnet_terminate_urbs(dev);
660 
661 	usb_kill_urb(dev->interrupt);
662 
663 	usbnet_purge_paused_rxq(dev);
664 
665 	/* deferred work (task, timer, softirq) must also stop.
666 	 * can't flush_scheduled_work() until we drop rtnl (later),
667 	 * else workers could deadlock; so make workers a NOP.
668 	 */
669 	dev->flags = 0;
670 	del_timer_sync (&dev->delay);
671 	tasklet_kill (&dev->bh);
672 	if (info->manage_power)
673 		info->manage_power(dev, 0);
674 	else
675 		usb_autopm_put_interface(dev->intf);
676 
677 	return 0;
678 }
679 EXPORT_SYMBOL_GPL(usbnet_stop);
680 
681 /*-------------------------------------------------------------------------*/
682 
683 // posts reads, and enables write queuing
684 
685 // precondition: never called in_interrupt
686 
687 int usbnet_open (struct net_device *net)
688 {
689 	struct usbnet		*dev = netdev_priv(net);
690 	int			retval;
691 	struct driver_info	*info = dev->driver_info;
692 
693 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
694 		netif_info(dev, ifup, dev->net,
695 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
696 			   retval,
697 			   dev->udev->bus->bus_name,
698 			   dev->udev->devpath,
699 			   info->description);
700 		goto done_nopm;
701 	}
702 
703 	// put into "known safe" state
704 	if (info->reset && (retval = info->reset (dev)) < 0) {
705 		netif_info(dev, ifup, dev->net,
706 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
707 			   retval,
708 			   dev->udev->bus->bus_name,
709 			   dev->udev->devpath,
710 			   info->description);
711 		goto done;
712 	}
713 
714 	// insist peer be connected
715 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
716 		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
717 		goto done;
718 	}
719 
720 	/* start any status interrupt transfer */
721 	if (dev->interrupt) {
722 		retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
723 		if (retval < 0) {
724 			netif_err(dev, ifup, dev->net,
725 				  "intr submit %d\n", retval);
726 			goto done;
727 		}
728 	}
729 
730 	netif_start_queue (net);
731 	netif_info(dev, ifup, dev->net,
732 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
733 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
734 		   dev->net->mtu,
735 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
736 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
737 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
738 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
739 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
740 		   "simple");
741 
742 	// delay posting reads until we're fully open
743 	tasklet_schedule (&dev->bh);
744 	if (info->manage_power) {
745 		retval = info->manage_power(dev, 1);
746 		if (retval < 0)
747 			goto done;
748 		usb_autopm_put_interface(dev->intf);
749 	}
750 	return retval;
751 
752 done:
753 	usb_autopm_put_interface(dev->intf);
754 done_nopm:
755 	return retval;
756 }
757 EXPORT_SYMBOL_GPL(usbnet_open);
758 
759 /*-------------------------------------------------------------------------*/
760 
761 /* ethtool methods; minidrivers may need to add some more, but
762  * they'll probably want to use this base set.
763  */
764 
765 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
766 {
767 	struct usbnet *dev = netdev_priv(net);
768 
769 	if (!dev->mii.mdio_read)
770 		return -EOPNOTSUPP;
771 
772 	return mii_ethtool_gset(&dev->mii, cmd);
773 }
774 EXPORT_SYMBOL_GPL(usbnet_get_settings);
775 
776 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
777 {
778 	struct usbnet *dev = netdev_priv(net);
779 	int retval;
780 
781 	if (!dev->mii.mdio_write)
782 		return -EOPNOTSUPP;
783 
784 	retval = mii_ethtool_sset(&dev->mii, cmd);
785 
786 	/* link speed/duplex might have changed */
787 	if (dev->driver_info->link_reset)
788 		dev->driver_info->link_reset(dev);
789 
790 	return retval;
791 
792 }
793 EXPORT_SYMBOL_GPL(usbnet_set_settings);
794 
795 u32 usbnet_get_link (struct net_device *net)
796 {
797 	struct usbnet *dev = netdev_priv(net);
798 
799 	/* If a check_connect is defined, return its result */
800 	if (dev->driver_info->check_connect)
801 		return dev->driver_info->check_connect (dev) == 0;
802 
803 	/* if the device has mii operations, use those */
804 	if (dev->mii.mdio_read)
805 		return mii_link_ok(&dev->mii);
806 
807 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
808 	return ethtool_op_get_link(net);
809 }
810 EXPORT_SYMBOL_GPL(usbnet_get_link);
811 
812 int usbnet_nway_reset(struct net_device *net)
813 {
814 	struct usbnet *dev = netdev_priv(net);
815 
816 	if (!dev->mii.mdio_write)
817 		return -EOPNOTSUPP;
818 
819 	return mii_nway_restart(&dev->mii);
820 }
821 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
822 
823 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
824 {
825 	struct usbnet *dev = netdev_priv(net);
826 
827 	strncpy (info->driver, dev->driver_name, sizeof info->driver);
828 	strncpy (info->version, DRIVER_VERSION, sizeof info->version);
829 	strncpy (info->fw_version, dev->driver_info->description,
830 		sizeof info->fw_version);
831 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
832 }
833 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
834 
835 u32 usbnet_get_msglevel (struct net_device *net)
836 {
837 	struct usbnet *dev = netdev_priv(net);
838 
839 	return dev->msg_enable;
840 }
841 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
842 
843 void usbnet_set_msglevel (struct net_device *net, u32 level)
844 {
845 	struct usbnet *dev = netdev_priv(net);
846 
847 	dev->msg_enable = level;
848 }
849 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
850 
851 /* drivers may override default ethtool_ops in their bind() routine */
852 static const struct ethtool_ops usbnet_ethtool_ops = {
853 	.get_settings		= usbnet_get_settings,
854 	.set_settings		= usbnet_set_settings,
855 	.get_link		= usbnet_get_link,
856 	.nway_reset		= usbnet_nway_reset,
857 	.get_drvinfo		= usbnet_get_drvinfo,
858 	.get_msglevel		= usbnet_get_msglevel,
859 	.set_msglevel		= usbnet_set_msglevel,
860 };
861 
862 /*-------------------------------------------------------------------------*/
863 
864 /* work that cannot be done in interrupt context uses keventd.
865  *
866  * NOTE:  with 2.5 we could do more of this using completion callbacks,
867  * especially now that control transfers can be queued.
868  */
869 static void
870 kevent (struct work_struct *work)
871 {
872 	struct usbnet		*dev =
873 		container_of(work, struct usbnet, kevent);
874 	int			status;
875 
876 	/* usb_clear_halt() needs a thread context */
877 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
878 		unlink_urbs (dev, &dev->txq);
879 		status = usb_autopm_get_interface(dev->intf);
880 		if (status < 0)
881 			goto fail_pipe;
882 		status = usb_clear_halt (dev->udev, dev->out);
883 		usb_autopm_put_interface(dev->intf);
884 		if (status < 0 &&
885 		    status != -EPIPE &&
886 		    status != -ESHUTDOWN) {
887 			if (netif_msg_tx_err (dev))
888 fail_pipe:
889 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
890 					   status);
891 		} else {
892 			clear_bit (EVENT_TX_HALT, &dev->flags);
893 			if (status != -ESHUTDOWN)
894 				netif_wake_queue (dev->net);
895 		}
896 	}
897 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
898 		unlink_urbs (dev, &dev->rxq);
899 		status = usb_autopm_get_interface(dev->intf);
900 		if (status < 0)
901 			goto fail_halt;
902 		status = usb_clear_halt (dev->udev, dev->in);
903 		usb_autopm_put_interface(dev->intf);
904 		if (status < 0 &&
905 		    status != -EPIPE &&
906 		    status != -ESHUTDOWN) {
907 			if (netif_msg_rx_err (dev))
908 fail_halt:
909 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
910 					   status);
911 		} else {
912 			clear_bit (EVENT_RX_HALT, &dev->flags);
913 			tasklet_schedule (&dev->bh);
914 		}
915 	}
916 
917 	/* tasklet could resubmit itself forever if memory is tight */
918 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
919 		struct urb	*urb = NULL;
920 		int resched = 1;
921 
922 		if (netif_running (dev->net))
923 			urb = usb_alloc_urb (0, GFP_KERNEL);
924 		else
925 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
926 		if (urb != NULL) {
927 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
928 			status = usb_autopm_get_interface(dev->intf);
929 			if (status < 0)
930 				goto fail_lowmem;
931 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
932 				resched = 0;
933 			usb_autopm_put_interface(dev->intf);
934 fail_lowmem:
935 			if (resched)
936 				tasklet_schedule (&dev->bh);
937 		}
938 	}
939 
940 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
941 		struct driver_info	*info = dev->driver_info;
942 		int			retval = 0;
943 
944 		clear_bit (EVENT_LINK_RESET, &dev->flags);
945 		status = usb_autopm_get_interface(dev->intf);
946 		if (status < 0)
947 			goto skip_reset;
948 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
949 			usb_autopm_put_interface(dev->intf);
950 skip_reset:
951 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
952 				    retval,
953 				    dev->udev->bus->bus_name,
954 				    dev->udev->devpath,
955 				    info->description);
956 		} else {
957 			usb_autopm_put_interface(dev->intf);
958 		}
959 	}
960 
961 	if (dev->flags)
962 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
963 }
964 
965 /*-------------------------------------------------------------------------*/
966 
967 static void tx_complete (struct urb *urb)
968 {
969 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
970 	struct skb_data		*entry = (struct skb_data *) skb->cb;
971 	struct usbnet		*dev = entry->dev;
972 
973 	if (urb->status == 0) {
974 		dev->net->stats.tx_packets++;
975 		dev->net->stats.tx_bytes += entry->length;
976 	} else {
977 		dev->net->stats.tx_errors++;
978 
979 		switch (urb->status) {
980 		case -EPIPE:
981 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
982 			break;
983 
984 		/* software-driven interface shutdown */
985 		case -ECONNRESET:		// async unlink
986 		case -ESHUTDOWN:		// hardware gone
987 			break;
988 
989 		// like rx, tx gets controller i/o faults during khubd delays
990 		// and so it uses the same throttling mechanism.
991 		case -EPROTO:
992 		case -ETIME:
993 		case -EILSEQ:
994 			usb_mark_last_busy(dev->udev);
995 			if (!timer_pending (&dev->delay)) {
996 				mod_timer (&dev->delay,
997 					jiffies + THROTTLE_JIFFIES);
998 				netif_dbg(dev, link, dev->net,
999 					  "tx throttle %d\n", urb->status);
1000 			}
1001 			netif_stop_queue (dev->net);
1002 			break;
1003 		default:
1004 			netif_dbg(dev, tx_err, dev->net,
1005 				  "tx err %d\n", entry->urb->status);
1006 			break;
1007 		}
1008 	}
1009 
1010 	usb_autopm_put_interface_async(dev->intf);
1011 	urb->dev = NULL;
1012 	entry->state = tx_done;
1013 	defer_bh(dev, skb, &dev->txq);
1014 }
1015 
1016 /*-------------------------------------------------------------------------*/
1017 
1018 void usbnet_tx_timeout (struct net_device *net)
1019 {
1020 	struct usbnet		*dev = netdev_priv(net);
1021 
1022 	unlink_urbs (dev, &dev->txq);
1023 	tasklet_schedule (&dev->bh);
1024 
1025 	// FIXME: device recovery -- reset?
1026 }
1027 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1028 
1029 /*-------------------------------------------------------------------------*/
1030 
1031 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1032 				     struct net_device *net)
1033 {
1034 	struct usbnet		*dev = netdev_priv(net);
1035 	int			length;
1036 	struct urb		*urb = NULL;
1037 	struct skb_data		*entry;
1038 	struct driver_info	*info = dev->driver_info;
1039 	unsigned long		flags;
1040 	int retval;
1041 
1042 	// some devices want funky USB-level framing, for
1043 	// win32 driver (usually) and/or hardware quirks
1044 	if (info->tx_fixup) {
1045 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1046 		if (!skb) {
1047 			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1048 			goto drop;
1049 		}
1050 	}
1051 	length = skb->len;
1052 
1053 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1054 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1055 		goto drop;
1056 	}
1057 
1058 	entry = (struct skb_data *) skb->cb;
1059 	entry->urb = urb;
1060 	entry->dev = dev;
1061 	entry->state = tx_start;
1062 	entry->length = length;
1063 
1064 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1065 			skb->data, skb->len, tx_complete, skb);
1066 
1067 	/* don't assume the hardware handles USB_ZERO_PACKET
1068 	 * NOTE:  strictly conforming cdc-ether devices should expect
1069 	 * the ZLP here, but ignore the one-byte packet.
1070 	 */
1071 	if (length % dev->maxpacket == 0) {
1072 		if (!(info->flags & FLAG_SEND_ZLP)) {
1073 			urb->transfer_buffer_length++;
1074 			if (skb_tailroom(skb)) {
1075 				skb->data[skb->len] = 0;
1076 				__skb_put(skb, 1);
1077 			}
1078 		} else
1079 			urb->transfer_flags |= URB_ZERO_PACKET;
1080 	}
1081 
1082 	spin_lock_irqsave(&dev->txq.lock, flags);
1083 	retval = usb_autopm_get_interface_async(dev->intf);
1084 	if (retval < 0) {
1085 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1086 		goto drop;
1087 	}
1088 
1089 #ifdef CONFIG_PM
1090 	/* if this triggers the device is still a sleep */
1091 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1092 		/* transmission will be done in resume */
1093 		usb_anchor_urb(urb, &dev->deferred);
1094 		/* no use to process more packets */
1095 		netif_stop_queue(net);
1096 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1097 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1098 		goto deferred;
1099 	}
1100 #endif
1101 
1102 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1103 	case -EPIPE:
1104 		netif_stop_queue (net);
1105 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1106 		usb_autopm_put_interface_async(dev->intf);
1107 		break;
1108 	default:
1109 		usb_autopm_put_interface_async(dev->intf);
1110 		netif_dbg(dev, tx_err, dev->net,
1111 			  "tx: submit urb err %d\n", retval);
1112 		break;
1113 	case 0:
1114 		net->trans_start = jiffies;
1115 		__skb_queue_tail (&dev->txq, skb);
1116 		if (dev->txq.qlen >= TX_QLEN (dev))
1117 			netif_stop_queue (net);
1118 	}
1119 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1120 
1121 	if (retval) {
1122 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1123 drop:
1124 		dev->net->stats.tx_dropped++;
1125 		if (skb)
1126 			dev_kfree_skb_any (skb);
1127 		usb_free_urb (urb);
1128 	} else
1129 		netif_dbg(dev, tx_queued, dev->net,
1130 			  "> tx, len %d, type 0x%x\n", length, skb->protocol);
1131 #ifdef CONFIG_PM
1132 deferred:
1133 #endif
1134 	return NETDEV_TX_OK;
1135 }
1136 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1137 
1138 /*-------------------------------------------------------------------------*/
1139 
1140 // tasklet (work deferred from completions, in_irq) or timer
1141 
1142 static void usbnet_bh (unsigned long param)
1143 {
1144 	struct usbnet		*dev = (struct usbnet *) param;
1145 	struct sk_buff		*skb;
1146 	struct skb_data		*entry;
1147 
1148 	while ((skb = skb_dequeue (&dev->done))) {
1149 		entry = (struct skb_data *) skb->cb;
1150 		switch (entry->state) {
1151 		case rx_done:
1152 			entry->state = rx_cleanup;
1153 			rx_process (dev, skb);
1154 			continue;
1155 		case tx_done:
1156 		case rx_cleanup:
1157 			usb_free_urb (entry->urb);
1158 			dev_kfree_skb (skb);
1159 			continue;
1160 		default:
1161 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1162 		}
1163 	}
1164 
1165 	// waiting for all pending urbs to complete?
1166 	if (dev->wait) {
1167 		if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
1168 			wake_up (dev->wait);
1169 		}
1170 
1171 	// or are we maybe short a few urbs?
1172 	} else if (netif_running (dev->net) &&
1173 		   netif_device_present (dev->net) &&
1174 		   !timer_pending (&dev->delay) &&
1175 		   !test_bit (EVENT_RX_HALT, &dev->flags)) {
1176 		int	temp = dev->rxq.qlen;
1177 		int	qlen = RX_QLEN (dev);
1178 
1179 		if (temp < qlen) {
1180 			struct urb	*urb;
1181 			int		i;
1182 
1183 			// don't refill the queue all at once
1184 			for (i = 0; i < 10 && dev->rxq.qlen < qlen; i++) {
1185 				urb = usb_alloc_urb (0, GFP_ATOMIC);
1186 				if (urb != NULL) {
1187 					if (rx_submit (dev, urb, GFP_ATOMIC) ==
1188 					    -ENOLINK)
1189 						return;
1190 				}
1191 			}
1192 			if (temp != dev->rxq.qlen)
1193 				netif_dbg(dev, link, dev->net,
1194 					  "rxqlen %d --> %d\n",
1195 					  temp, dev->rxq.qlen);
1196 			if (dev->rxq.qlen < qlen)
1197 				tasklet_schedule (&dev->bh);
1198 		}
1199 		if (dev->txq.qlen < TX_QLEN (dev))
1200 			netif_wake_queue (dev->net);
1201 	}
1202 }
1203 
1204 
1205 /*-------------------------------------------------------------------------
1206  *
1207  * USB Device Driver support
1208  *
1209  *-------------------------------------------------------------------------*/
1210 
1211 // precondition: never called in_interrupt
1212 
1213 void usbnet_disconnect (struct usb_interface *intf)
1214 {
1215 	struct usbnet		*dev;
1216 	struct usb_device	*xdev;
1217 	struct net_device	*net;
1218 
1219 	dev = usb_get_intfdata(intf);
1220 	usb_set_intfdata(intf, NULL);
1221 	if (!dev)
1222 		return;
1223 
1224 	xdev = interface_to_usbdev (intf);
1225 
1226 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1227 		   intf->dev.driver->name,
1228 		   xdev->bus->bus_name, xdev->devpath,
1229 		   dev->driver_info->description);
1230 
1231 	net = dev->net;
1232 	unregister_netdev (net);
1233 
1234 	/* we don't hold rtnl here ... */
1235 	flush_scheduled_work ();
1236 
1237 	if (dev->driver_info->unbind)
1238 		dev->driver_info->unbind (dev, intf);
1239 
1240 	free_netdev(net);
1241 	usb_put_dev (xdev);
1242 }
1243 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1244 
1245 static const struct net_device_ops usbnet_netdev_ops = {
1246 	.ndo_open		= usbnet_open,
1247 	.ndo_stop		= usbnet_stop,
1248 	.ndo_start_xmit		= usbnet_start_xmit,
1249 	.ndo_tx_timeout		= usbnet_tx_timeout,
1250 	.ndo_change_mtu		= usbnet_change_mtu,
1251 	.ndo_set_mac_address 	= eth_mac_addr,
1252 	.ndo_validate_addr	= eth_validate_addr,
1253 };
1254 
1255 /*-------------------------------------------------------------------------*/
1256 
1257 // precondition: never called in_interrupt
1258 
1259 static struct device_type wlan_type = {
1260 	.name	= "wlan",
1261 };
1262 
1263 static struct device_type wwan_type = {
1264 	.name	= "wwan",
1265 };
1266 
1267 int
1268 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1269 {
1270 	struct usbnet			*dev;
1271 	struct net_device		*net;
1272 	struct usb_host_interface	*interface;
1273 	struct driver_info		*info;
1274 	struct usb_device		*xdev;
1275 	int				status;
1276 	const char			*name;
1277 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1278 
1279 	/* usbnet already took usb runtime pm, so have to enable the feature
1280 	 * for usb interface, otherwise usb_autopm_get_interface may return
1281 	 * failure if USB_SUSPEND(RUNTIME_PM) is enabled.
1282 	 */
1283 	if (!driver->supports_autosuspend) {
1284 		driver->supports_autosuspend = 1;
1285 		pm_runtime_enable(&udev->dev);
1286 	}
1287 
1288 	name = udev->dev.driver->name;
1289 	info = (struct driver_info *) prod->driver_info;
1290 	if (!info) {
1291 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1292 		return -ENODEV;
1293 	}
1294 	xdev = interface_to_usbdev (udev);
1295 	interface = udev->cur_altsetting;
1296 
1297 	usb_get_dev (xdev);
1298 
1299 	status = -ENOMEM;
1300 
1301 	// set up our own records
1302 	net = alloc_etherdev(sizeof(*dev));
1303 	if (!net) {
1304 		dbg ("can't kmalloc dev");
1305 		goto out;
1306 	}
1307 
1308 	/* netdev_printk() needs this so do it as early as possible */
1309 	SET_NETDEV_DEV(net, &udev->dev);
1310 
1311 	dev = netdev_priv(net);
1312 	dev->udev = xdev;
1313 	dev->intf = udev;
1314 	dev->driver_info = info;
1315 	dev->driver_name = name;
1316 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1317 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1318 	skb_queue_head_init (&dev->rxq);
1319 	skb_queue_head_init (&dev->txq);
1320 	skb_queue_head_init (&dev->done);
1321 	skb_queue_head_init(&dev->rxq_pause);
1322 	dev->bh.func = usbnet_bh;
1323 	dev->bh.data = (unsigned long) dev;
1324 	INIT_WORK (&dev->kevent, kevent);
1325 	init_usb_anchor(&dev->deferred);
1326 	dev->delay.function = usbnet_bh;
1327 	dev->delay.data = (unsigned long) dev;
1328 	init_timer (&dev->delay);
1329 	mutex_init (&dev->phy_mutex);
1330 
1331 	dev->net = net;
1332 	strcpy (net->name, "usb%d");
1333 	memcpy (net->dev_addr, node_id, sizeof node_id);
1334 
1335 	/* rx and tx sides can use different message sizes;
1336 	 * bind() should set rx_urb_size in that case.
1337 	 */
1338 	dev->hard_mtu = net->mtu + net->hard_header_len;
1339 #if 0
1340 // dma_supported() is deeply broken on almost all architectures
1341 	// possible with some EHCI controllers
1342 	if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1343 		net->features |= NETIF_F_HIGHDMA;
1344 #endif
1345 
1346 	net->netdev_ops = &usbnet_netdev_ops;
1347 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1348 	net->ethtool_ops = &usbnet_ethtool_ops;
1349 
1350 	// allow device-specific bind/init procedures
1351 	// NOTE net->name still not usable ...
1352 	if (info->bind) {
1353 		status = info->bind (dev, udev);
1354 		if (status < 0)
1355 			goto out1;
1356 
1357 		// heuristic:  "usb%d" for links we know are two-host,
1358 		// else "eth%d" when there's reasonable doubt.  userspace
1359 		// can rename the link if it knows better.
1360 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1361 		    (net->dev_addr [0] & 0x02) == 0)
1362 			strcpy (net->name, "eth%d");
1363 		/* WLAN devices should always be named "wlan%d" */
1364 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1365 			strcpy(net->name, "wlan%d");
1366 		/* WWAN devices should always be named "wwan%d" */
1367 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1368 			strcpy(net->name, "wwan%d");
1369 
1370 		/* maybe the remote can't receive an Ethernet MTU */
1371 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1372 			net->mtu = dev->hard_mtu - net->hard_header_len;
1373 	} else if (!info->in || !info->out)
1374 		status = usbnet_get_endpoints (dev, udev);
1375 	else {
1376 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1377 		dev->out = usb_sndbulkpipe (xdev, info->out);
1378 		if (!(info->flags & FLAG_NO_SETINT))
1379 			status = usb_set_interface (xdev,
1380 				interface->desc.bInterfaceNumber,
1381 				interface->desc.bAlternateSetting);
1382 		else
1383 			status = 0;
1384 
1385 	}
1386 	if (status >= 0 && dev->status)
1387 		status = init_status (dev, udev);
1388 	if (status < 0)
1389 		goto out3;
1390 
1391 	if (!dev->rx_urb_size)
1392 		dev->rx_urb_size = dev->hard_mtu;
1393 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1394 
1395 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1396 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1397 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1398 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1399 
1400 	status = register_netdev (net);
1401 	if (status)
1402 		goto out3;
1403 	netif_info(dev, probe, dev->net,
1404 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1405 		   udev->dev.driver->name,
1406 		   xdev->bus->bus_name, xdev->devpath,
1407 		   dev->driver_info->description,
1408 		   net->dev_addr);
1409 
1410 	// ok, it's ready to go.
1411 	usb_set_intfdata (udev, dev);
1412 
1413 	netif_device_attach (net);
1414 
1415 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1416 		netif_carrier_off(net);
1417 
1418 	return 0;
1419 
1420 out3:
1421 	if (info->unbind)
1422 		info->unbind (dev, udev);
1423 out1:
1424 	free_netdev(net);
1425 out:
1426 	usb_put_dev(xdev);
1427 	return status;
1428 }
1429 EXPORT_SYMBOL_GPL(usbnet_probe);
1430 
1431 /*-------------------------------------------------------------------------*/
1432 
1433 /*
1434  * suspend the whole driver as soon as the first interface is suspended
1435  * resume only when the last interface is resumed
1436  */
1437 
1438 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1439 {
1440 	struct usbnet		*dev = usb_get_intfdata(intf);
1441 
1442 	if (!dev->suspend_count++) {
1443 		spin_lock_irq(&dev->txq.lock);
1444 		/* don't autosuspend while transmitting */
1445 		if (dev->txq.qlen && (message.event & PM_EVENT_AUTO)) {
1446 			spin_unlock_irq(&dev->txq.lock);
1447 			return -EBUSY;
1448 		} else {
1449 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1450 			spin_unlock_irq(&dev->txq.lock);
1451 		}
1452 		/*
1453 		 * accelerate emptying of the rx and queues, to avoid
1454 		 * having everything error out.
1455 		 */
1456 		netif_device_detach (dev->net);
1457 		usbnet_terminate_urbs(dev);
1458 		usb_kill_urb(dev->interrupt);
1459 
1460 		/*
1461 		 * reattach so runtime management can use and
1462 		 * wake the device
1463 		 */
1464 		netif_device_attach (dev->net);
1465 	}
1466 	return 0;
1467 }
1468 EXPORT_SYMBOL_GPL(usbnet_suspend);
1469 
1470 int usbnet_resume (struct usb_interface *intf)
1471 {
1472 	struct usbnet		*dev = usb_get_intfdata(intf);
1473 	struct sk_buff          *skb;
1474 	struct urb              *res;
1475 	int                     retval;
1476 
1477 	if (!--dev->suspend_count) {
1478 		spin_lock_irq(&dev->txq.lock);
1479 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1480 
1481 			skb = (struct sk_buff *)res->context;
1482 			retval = usb_submit_urb(res, GFP_ATOMIC);
1483 			if (retval < 0) {
1484 				dev_kfree_skb_any(skb);
1485 				usb_free_urb(res);
1486 				usb_autopm_put_interface_async(dev->intf);
1487 			} else {
1488 				dev->net->trans_start = jiffies;
1489 				__skb_queue_tail(&dev->txq, skb);
1490 			}
1491 		}
1492 
1493 		smp_mb();
1494 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1495 		spin_unlock_irq(&dev->txq.lock);
1496 		if (!(dev->txq.qlen >= TX_QLEN(dev)))
1497 			netif_start_queue(dev->net);
1498 		tasklet_schedule (&dev->bh);
1499 	}
1500 	return 0;
1501 }
1502 EXPORT_SYMBOL_GPL(usbnet_resume);
1503 
1504 
1505 /*-------------------------------------------------------------------------*/
1506 
1507 static int __init usbnet_init(void)
1508 {
1509 	/* compiler should optimize this out */
1510 	BUILD_BUG_ON (sizeof (((struct sk_buff *)0)->cb)
1511 			< sizeof (struct skb_data));
1512 
1513 	random_ether_addr(node_id);
1514 	return 0;
1515 }
1516 module_init(usbnet_init);
1517 
1518 static void __exit usbnet_exit(void)
1519 {
1520 }
1521 module_exit(usbnet_exit);
1522 
1523 MODULE_AUTHOR("David Brownell");
1524 MODULE_DESCRIPTION("USB network driver framework");
1525 MODULE_LICENSE("GPL");
1526