xref: /openbmc/linux/drivers/net/usb/usbnet.c (revision 7490ca1e)
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 altsettings.
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 
242 	if (skb_defer_rx_timestamp(skb))
243 		return;
244 
245 	status = netif_rx (skb);
246 	if (status != NET_RX_SUCCESS)
247 		netif_dbg(dev, rx_err, dev->net,
248 			  "netif_rx status %d\n", status);
249 }
250 EXPORT_SYMBOL_GPL(usbnet_skb_return);
251 
252 
253 /*-------------------------------------------------------------------------
254  *
255  * Network Device Driver (peer link to "Host Device", from USB host)
256  *
257  *-------------------------------------------------------------------------*/
258 
259 int usbnet_change_mtu (struct net_device *net, int new_mtu)
260 {
261 	struct usbnet	*dev = netdev_priv(net);
262 	int		ll_mtu = new_mtu + net->hard_header_len;
263 	int		old_hard_mtu = dev->hard_mtu;
264 	int		old_rx_urb_size = dev->rx_urb_size;
265 
266 	if (new_mtu <= 0)
267 		return -EINVAL;
268 	// no second zero-length packet read wanted after mtu-sized packets
269 	if ((ll_mtu % dev->maxpacket) == 0)
270 		return -EDOM;
271 	net->mtu = new_mtu;
272 
273 	dev->hard_mtu = net->mtu + net->hard_header_len;
274 	if (dev->rx_urb_size == old_hard_mtu) {
275 		dev->rx_urb_size = dev->hard_mtu;
276 		if (dev->rx_urb_size > old_rx_urb_size)
277 			usbnet_unlink_rx_urbs(dev);
278 	}
279 
280 	return 0;
281 }
282 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
283 
284 /*-------------------------------------------------------------------------*/
285 
286 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
287  * completion callbacks.  2.5 should have fixed those bugs...
288  */
289 
290 static void defer_bh(struct usbnet *dev, struct sk_buff *skb, struct sk_buff_head *list)
291 {
292 	unsigned long		flags;
293 
294 	spin_lock_irqsave(&list->lock, flags);
295 	__skb_unlink(skb, list);
296 	spin_unlock(&list->lock);
297 	spin_lock(&dev->done.lock);
298 	__skb_queue_tail(&dev->done, skb);
299 	if (dev->done.qlen == 1)
300 		tasklet_schedule(&dev->bh);
301 	spin_unlock_irqrestore(&dev->done.lock, flags);
302 }
303 
304 /* some work can't be done in tasklets, so we use keventd
305  *
306  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
307  * but tasklet_schedule() doesn't.  hope the failure is rare.
308  */
309 void usbnet_defer_kevent (struct usbnet *dev, int work)
310 {
311 	set_bit (work, &dev->flags);
312 	if (!schedule_work (&dev->kevent))
313 		netdev_err(dev->net, "kevent %d may have been dropped\n", work);
314 	else
315 		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
316 }
317 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
318 
319 /*-------------------------------------------------------------------------*/
320 
321 static void rx_complete (struct urb *urb);
322 
323 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
324 {
325 	struct sk_buff		*skb;
326 	struct skb_data		*entry;
327 	int			retval = 0;
328 	unsigned long		lockflags;
329 	size_t			size = dev->rx_urb_size;
330 
331 	if ((skb = alloc_skb (size + NET_IP_ALIGN, flags)) == NULL) {
332 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
333 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
334 		usb_free_urb (urb);
335 		return -ENOMEM;
336 	}
337 	skb_reserve (skb, NET_IP_ALIGN);
338 
339 	entry = (struct skb_data *) skb->cb;
340 	entry->urb = urb;
341 	entry->dev = dev;
342 	entry->state = rx_start;
343 	entry->length = 0;
344 
345 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
346 		skb->data, size, rx_complete, skb);
347 
348 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
349 
350 	if (netif_running (dev->net) &&
351 	    netif_device_present (dev->net) &&
352 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
353 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
354 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
355 		case -EPIPE:
356 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
357 			break;
358 		case -ENOMEM:
359 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
360 			break;
361 		case -ENODEV:
362 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
363 			netif_device_detach (dev->net);
364 			break;
365 		case -EHOSTUNREACH:
366 			retval = -ENOLINK;
367 			break;
368 		default:
369 			netif_dbg(dev, rx_err, dev->net,
370 				  "rx submit, %d\n", retval);
371 			tasklet_schedule (&dev->bh);
372 			break;
373 		case 0:
374 			__skb_queue_tail (&dev->rxq, skb);
375 		}
376 	} else {
377 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
378 		retval = -ENOLINK;
379 	}
380 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
381 	if (retval) {
382 		dev_kfree_skb_any (skb);
383 		usb_free_urb (urb);
384 	}
385 	return retval;
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 		/* With RX_ASSEMBLE, rx_fixup() must update counters */
396 		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
397 			dev->net->stats.rx_errors++;
398 		goto done;
399 	}
400 	// else network stack removes extra byte if we forced a short packet
401 
402 	if (skb->len) {
403 		/* all data was already cloned from skb inside the driver */
404 		if (dev->driver_info->flags & FLAG_MULTI_PACKET)
405 			dev_kfree_skb_any(skb);
406 		else
407 			usbnet_skb_return(dev, skb);
408 		return;
409 	}
410 
411 	netif_dbg(dev, rx_err, dev->net, "drop\n");
412 	dev->net->stats.rx_errors++;
413 done:
414 	skb_queue_tail(&dev->done, skb);
415 }
416 
417 /*-------------------------------------------------------------------------*/
418 
419 static void rx_complete (struct urb *urb)
420 {
421 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
422 	struct skb_data		*entry = (struct skb_data *) skb->cb;
423 	struct usbnet		*dev = entry->dev;
424 	int			urb_status = urb->status;
425 
426 	skb_put (skb, urb->actual_length);
427 	entry->state = rx_done;
428 	entry->urb = NULL;
429 
430 	switch (urb_status) {
431 	/* success */
432 	case 0:
433 		if (skb->len < dev->net->hard_header_len) {
434 			entry->state = rx_cleanup;
435 			dev->net->stats.rx_errors++;
436 			dev->net->stats.rx_length_errors++;
437 			netif_dbg(dev, rx_err, dev->net,
438 				  "rx length %d\n", skb->len);
439 		}
440 		break;
441 
442 	/* stalls need manual reset. this is rare ... except that
443 	 * when going through USB 2.0 TTs, unplug appears this way.
444 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
445 	 * storm, recovering as needed.
446 	 */
447 	case -EPIPE:
448 		dev->net->stats.rx_errors++;
449 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
450 		// FALLTHROUGH
451 
452 	/* software-driven interface shutdown */
453 	case -ECONNRESET:		/* async unlink */
454 	case -ESHUTDOWN:		/* hardware gone */
455 		netif_dbg(dev, ifdown, dev->net,
456 			  "rx shutdown, code %d\n", urb_status);
457 		goto block;
458 
459 	/* we get controller i/o faults during khubd disconnect() delays.
460 	 * throttle down resubmits, to avoid log floods; just temporarily,
461 	 * so we still recover when the fault isn't a khubd delay.
462 	 */
463 	case -EPROTO:
464 	case -ETIME:
465 	case -EILSEQ:
466 		dev->net->stats.rx_errors++;
467 		if (!timer_pending (&dev->delay)) {
468 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
469 			netif_dbg(dev, link, dev->net,
470 				  "rx throttle %d\n", urb_status);
471 		}
472 block:
473 		entry->state = rx_cleanup;
474 		entry->urb = urb;
475 		urb = NULL;
476 		break;
477 
478 	/* data overrun ... flush fifo? */
479 	case -EOVERFLOW:
480 		dev->net->stats.rx_over_errors++;
481 		// FALLTHROUGH
482 
483 	default:
484 		entry->state = rx_cleanup;
485 		dev->net->stats.rx_errors++;
486 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
487 		break;
488 	}
489 
490 	defer_bh(dev, skb, &dev->rxq);
491 
492 	if (urb) {
493 		if (netif_running (dev->net) &&
494 		    !test_bit (EVENT_RX_HALT, &dev->flags)) {
495 			rx_submit (dev, urb, GFP_ATOMIC);
496 			return;
497 		}
498 		usb_free_urb (urb);
499 	}
500 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
501 }
502 
503 static void intr_complete (struct urb *urb)
504 {
505 	struct usbnet	*dev = urb->context;
506 	int		status = urb->status;
507 
508 	switch (status) {
509 	/* success */
510 	case 0:
511 		dev->driver_info->status(dev, urb);
512 		break;
513 
514 	/* software-driven interface shutdown */
515 	case -ENOENT:		/* urb killed */
516 	case -ESHUTDOWN:	/* hardware gone */
517 		netif_dbg(dev, ifdown, dev->net,
518 			  "intr shutdown, code %d\n", status);
519 		return;
520 
521 	/* NOTE:  not throttling like RX/TX, since this endpoint
522 	 * already polls infrequently
523 	 */
524 	default:
525 		netdev_dbg(dev->net, "intr status %d\n", status);
526 		break;
527 	}
528 
529 	if (!netif_running (dev->net))
530 		return;
531 
532 	memset(urb->transfer_buffer, 0, urb->transfer_buffer_length);
533 	status = usb_submit_urb (urb, GFP_ATOMIC);
534 	if (status != 0)
535 		netif_err(dev, timer, dev->net,
536 			  "intr resubmit --> %d\n", status);
537 }
538 
539 /*-------------------------------------------------------------------------*/
540 void usbnet_pause_rx(struct usbnet *dev)
541 {
542 	set_bit(EVENT_RX_PAUSED, &dev->flags);
543 
544 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
545 }
546 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
547 
548 void usbnet_resume_rx(struct usbnet *dev)
549 {
550 	struct sk_buff *skb;
551 	int num = 0;
552 
553 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
554 
555 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
556 		usbnet_skb_return(dev, skb);
557 		num++;
558 	}
559 
560 	tasklet_schedule(&dev->bh);
561 
562 	netif_dbg(dev, rx_status, dev->net,
563 		  "paused rx queue disabled, %d skbs requeued\n", num);
564 }
565 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
566 
567 void usbnet_purge_paused_rxq(struct usbnet *dev)
568 {
569 	skb_queue_purge(&dev->rxq_pause);
570 }
571 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
572 
573 /*-------------------------------------------------------------------------*/
574 
575 // unlink pending rx/tx; completion handlers do all other cleanup
576 
577 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
578 {
579 	unsigned long		flags;
580 	struct sk_buff		*skb, *skbnext;
581 	int			count = 0;
582 
583 	spin_lock_irqsave (&q->lock, flags);
584 	skb_queue_walk_safe(q, skb, skbnext) {
585 		struct skb_data		*entry;
586 		struct urb		*urb;
587 		int			retval;
588 
589 		entry = (struct skb_data *) skb->cb;
590 		urb = entry->urb;
591 
592 		// during some PM-driven resume scenarios,
593 		// these (async) unlinks complete immediately
594 		retval = usb_unlink_urb (urb);
595 		if (retval != -EINPROGRESS && retval != 0)
596 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
597 		else
598 			count++;
599 	}
600 	spin_unlock_irqrestore (&q->lock, flags);
601 	return count;
602 }
603 
604 // Flush all pending rx urbs
605 // minidrivers may need to do this when the MTU changes
606 
607 void usbnet_unlink_rx_urbs(struct usbnet *dev)
608 {
609 	if (netif_running(dev->net)) {
610 		(void) unlink_urbs (dev, &dev->rxq);
611 		tasklet_schedule(&dev->bh);
612 	}
613 }
614 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
615 
616 /*-------------------------------------------------------------------------*/
617 
618 // precondition: never called in_interrupt
619 static void usbnet_terminate_urbs(struct usbnet *dev)
620 {
621 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
622 	DECLARE_WAITQUEUE(wait, current);
623 	int temp;
624 
625 	/* ensure there are no more active urbs */
626 	add_wait_queue(&unlink_wakeup, &wait);
627 	set_current_state(TASK_UNINTERRUPTIBLE);
628 	dev->wait = &unlink_wakeup;
629 	temp = unlink_urbs(dev, &dev->txq) +
630 		unlink_urbs(dev, &dev->rxq);
631 
632 	/* maybe wait for deletions to finish. */
633 	while (!skb_queue_empty(&dev->rxq)
634 		&& !skb_queue_empty(&dev->txq)
635 		&& !skb_queue_empty(&dev->done)) {
636 			schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
637 			set_current_state(TASK_UNINTERRUPTIBLE);
638 			netif_dbg(dev, ifdown, dev->net,
639 				  "waited for %d urb completions\n", temp);
640 	}
641 	set_current_state(TASK_RUNNING);
642 	dev->wait = NULL;
643 	remove_wait_queue(&unlink_wakeup, &wait);
644 }
645 
646 int usbnet_stop (struct net_device *net)
647 {
648 	struct usbnet		*dev = netdev_priv(net);
649 	struct driver_info	*info = dev->driver_info;
650 	int			retval;
651 
652 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
653 	netif_stop_queue (net);
654 
655 	netif_info(dev, ifdown, dev->net,
656 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
657 		   net->stats.rx_packets, net->stats.tx_packets,
658 		   net->stats.rx_errors, net->stats.tx_errors);
659 
660 	/* allow minidriver to stop correctly (wireless devices to turn off
661 	 * radio etc) */
662 	if (info->stop) {
663 		retval = info->stop(dev);
664 		if (retval < 0)
665 			netif_info(dev, ifdown, dev->net,
666 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
667 				   retval,
668 				   dev->udev->bus->bus_name, dev->udev->devpath,
669 				   info->description);
670 	}
671 
672 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
673 		usbnet_terminate_urbs(dev);
674 
675 	usb_kill_urb(dev->interrupt);
676 
677 	usbnet_purge_paused_rxq(dev);
678 
679 	/* deferred work (task, timer, softirq) must also stop.
680 	 * can't flush_scheduled_work() until we drop rtnl (later),
681 	 * else workers could deadlock; so make workers a NOP.
682 	 */
683 	dev->flags = 0;
684 	del_timer_sync (&dev->delay);
685 	tasklet_kill (&dev->bh);
686 	if (info->manage_power)
687 		info->manage_power(dev, 0);
688 	else
689 		usb_autopm_put_interface(dev->intf);
690 
691 	return 0;
692 }
693 EXPORT_SYMBOL_GPL(usbnet_stop);
694 
695 /*-------------------------------------------------------------------------*/
696 
697 // posts reads, and enables write queuing
698 
699 // precondition: never called in_interrupt
700 
701 int usbnet_open (struct net_device *net)
702 {
703 	struct usbnet		*dev = netdev_priv(net);
704 	int			retval;
705 	struct driver_info	*info = dev->driver_info;
706 
707 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
708 		netif_info(dev, ifup, dev->net,
709 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
710 			   retval,
711 			   dev->udev->bus->bus_name,
712 			   dev->udev->devpath,
713 			   info->description);
714 		goto done_nopm;
715 	}
716 
717 	// put into "known safe" state
718 	if (info->reset && (retval = info->reset (dev)) < 0) {
719 		netif_info(dev, ifup, dev->net,
720 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
721 			   retval,
722 			   dev->udev->bus->bus_name,
723 			   dev->udev->devpath,
724 			   info->description);
725 		goto done;
726 	}
727 
728 	// insist peer be connected
729 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
730 		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
731 		goto done;
732 	}
733 
734 	/* start any status interrupt transfer */
735 	if (dev->interrupt) {
736 		retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
737 		if (retval < 0) {
738 			netif_err(dev, ifup, dev->net,
739 				  "intr submit %d\n", retval);
740 			goto done;
741 		}
742 	}
743 
744 	set_bit(EVENT_DEV_OPEN, &dev->flags);
745 	netif_start_queue (net);
746 	netif_info(dev, ifup, dev->net,
747 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
748 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
749 		   dev->net->mtu,
750 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
751 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
752 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
753 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
754 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
755 		   "simple");
756 
757 	// delay posting reads until we're fully open
758 	tasklet_schedule (&dev->bh);
759 	if (info->manage_power) {
760 		retval = info->manage_power(dev, 1);
761 		if (retval < 0)
762 			goto done;
763 		usb_autopm_put_interface(dev->intf);
764 	}
765 	return retval;
766 
767 done:
768 	usb_autopm_put_interface(dev->intf);
769 done_nopm:
770 	return retval;
771 }
772 EXPORT_SYMBOL_GPL(usbnet_open);
773 
774 /*-------------------------------------------------------------------------*/
775 
776 /* ethtool methods; minidrivers may need to add some more, but
777  * they'll probably want to use this base set.
778  */
779 
780 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
781 {
782 	struct usbnet *dev = netdev_priv(net);
783 
784 	if (!dev->mii.mdio_read)
785 		return -EOPNOTSUPP;
786 
787 	return mii_ethtool_gset(&dev->mii, cmd);
788 }
789 EXPORT_SYMBOL_GPL(usbnet_get_settings);
790 
791 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
792 {
793 	struct usbnet *dev = netdev_priv(net);
794 	int retval;
795 
796 	if (!dev->mii.mdio_write)
797 		return -EOPNOTSUPP;
798 
799 	retval = mii_ethtool_sset(&dev->mii, cmd);
800 
801 	/* link speed/duplex might have changed */
802 	if (dev->driver_info->link_reset)
803 		dev->driver_info->link_reset(dev);
804 
805 	return retval;
806 
807 }
808 EXPORT_SYMBOL_GPL(usbnet_set_settings);
809 
810 u32 usbnet_get_link (struct net_device *net)
811 {
812 	struct usbnet *dev = netdev_priv(net);
813 
814 	/* If a check_connect is defined, return its result */
815 	if (dev->driver_info->check_connect)
816 		return dev->driver_info->check_connect (dev) == 0;
817 
818 	/* if the device has mii operations, use those */
819 	if (dev->mii.mdio_read)
820 		return mii_link_ok(&dev->mii);
821 
822 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
823 	return ethtool_op_get_link(net);
824 }
825 EXPORT_SYMBOL_GPL(usbnet_get_link);
826 
827 int usbnet_nway_reset(struct net_device *net)
828 {
829 	struct usbnet *dev = netdev_priv(net);
830 
831 	if (!dev->mii.mdio_write)
832 		return -EOPNOTSUPP;
833 
834 	return mii_nway_restart(&dev->mii);
835 }
836 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
837 
838 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
839 {
840 	struct usbnet *dev = netdev_priv(net);
841 
842 	strncpy (info->driver, dev->driver_name, sizeof info->driver);
843 	strncpy (info->version, DRIVER_VERSION, sizeof info->version);
844 	strncpy (info->fw_version, dev->driver_info->description,
845 		sizeof info->fw_version);
846 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
847 }
848 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
849 
850 u32 usbnet_get_msglevel (struct net_device *net)
851 {
852 	struct usbnet *dev = netdev_priv(net);
853 
854 	return dev->msg_enable;
855 }
856 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
857 
858 void usbnet_set_msglevel (struct net_device *net, u32 level)
859 {
860 	struct usbnet *dev = netdev_priv(net);
861 
862 	dev->msg_enable = level;
863 }
864 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
865 
866 /* drivers may override default ethtool_ops in their bind() routine */
867 static const struct ethtool_ops usbnet_ethtool_ops = {
868 	.get_settings		= usbnet_get_settings,
869 	.set_settings		= usbnet_set_settings,
870 	.get_link		= usbnet_get_link,
871 	.nway_reset		= usbnet_nway_reset,
872 	.get_drvinfo		= usbnet_get_drvinfo,
873 	.get_msglevel		= usbnet_get_msglevel,
874 	.set_msglevel		= usbnet_set_msglevel,
875 };
876 
877 /*-------------------------------------------------------------------------*/
878 
879 /* work that cannot be done in interrupt context uses keventd.
880  *
881  * NOTE:  with 2.5 we could do more of this using completion callbacks,
882  * especially now that control transfers can be queued.
883  */
884 static void
885 kevent (struct work_struct *work)
886 {
887 	struct usbnet		*dev =
888 		container_of(work, struct usbnet, kevent);
889 	int			status;
890 
891 	/* usb_clear_halt() needs a thread context */
892 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
893 		unlink_urbs (dev, &dev->txq);
894 		status = usb_autopm_get_interface(dev->intf);
895 		if (status < 0)
896 			goto fail_pipe;
897 		status = usb_clear_halt (dev->udev, dev->out);
898 		usb_autopm_put_interface(dev->intf);
899 		if (status < 0 &&
900 		    status != -EPIPE &&
901 		    status != -ESHUTDOWN) {
902 			if (netif_msg_tx_err (dev))
903 fail_pipe:
904 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
905 					   status);
906 		} else {
907 			clear_bit (EVENT_TX_HALT, &dev->flags);
908 			if (status != -ESHUTDOWN)
909 				netif_wake_queue (dev->net);
910 		}
911 	}
912 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
913 		unlink_urbs (dev, &dev->rxq);
914 		status = usb_autopm_get_interface(dev->intf);
915 		if (status < 0)
916 			goto fail_halt;
917 		status = usb_clear_halt (dev->udev, dev->in);
918 		usb_autopm_put_interface(dev->intf);
919 		if (status < 0 &&
920 		    status != -EPIPE &&
921 		    status != -ESHUTDOWN) {
922 			if (netif_msg_rx_err (dev))
923 fail_halt:
924 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
925 					   status);
926 		} else {
927 			clear_bit (EVENT_RX_HALT, &dev->flags);
928 			tasklet_schedule (&dev->bh);
929 		}
930 	}
931 
932 	/* tasklet could resubmit itself forever if memory is tight */
933 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
934 		struct urb	*urb = NULL;
935 		int resched = 1;
936 
937 		if (netif_running (dev->net))
938 			urb = usb_alloc_urb (0, GFP_KERNEL);
939 		else
940 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
941 		if (urb != NULL) {
942 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
943 			status = usb_autopm_get_interface(dev->intf);
944 			if (status < 0) {
945 				usb_free_urb(urb);
946 				goto fail_lowmem;
947 			}
948 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
949 				resched = 0;
950 			usb_autopm_put_interface(dev->intf);
951 fail_lowmem:
952 			if (resched)
953 				tasklet_schedule (&dev->bh);
954 		}
955 	}
956 
957 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
958 		struct driver_info	*info = dev->driver_info;
959 		int			retval = 0;
960 
961 		clear_bit (EVENT_LINK_RESET, &dev->flags);
962 		status = usb_autopm_get_interface(dev->intf);
963 		if (status < 0)
964 			goto skip_reset;
965 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
966 			usb_autopm_put_interface(dev->intf);
967 skip_reset:
968 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
969 				    retval,
970 				    dev->udev->bus->bus_name,
971 				    dev->udev->devpath,
972 				    info->description);
973 		} else {
974 			usb_autopm_put_interface(dev->intf);
975 		}
976 	}
977 
978 	if (dev->flags)
979 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
980 }
981 
982 /*-------------------------------------------------------------------------*/
983 
984 static void tx_complete (struct urb *urb)
985 {
986 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
987 	struct skb_data		*entry = (struct skb_data *) skb->cb;
988 	struct usbnet		*dev = entry->dev;
989 
990 	if (urb->status == 0) {
991 		if (!(dev->driver_info->flags & FLAG_MULTI_PACKET))
992 			dev->net->stats.tx_packets++;
993 		dev->net->stats.tx_bytes += entry->length;
994 	} else {
995 		dev->net->stats.tx_errors++;
996 
997 		switch (urb->status) {
998 		case -EPIPE:
999 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1000 			break;
1001 
1002 		/* software-driven interface shutdown */
1003 		case -ECONNRESET:		// async unlink
1004 		case -ESHUTDOWN:		// hardware gone
1005 			break;
1006 
1007 		// like rx, tx gets controller i/o faults during khubd delays
1008 		// and so it uses the same throttling mechanism.
1009 		case -EPROTO:
1010 		case -ETIME:
1011 		case -EILSEQ:
1012 			usb_mark_last_busy(dev->udev);
1013 			if (!timer_pending (&dev->delay)) {
1014 				mod_timer (&dev->delay,
1015 					jiffies + THROTTLE_JIFFIES);
1016 				netif_dbg(dev, link, dev->net,
1017 					  "tx throttle %d\n", urb->status);
1018 			}
1019 			netif_stop_queue (dev->net);
1020 			break;
1021 		default:
1022 			netif_dbg(dev, tx_err, dev->net,
1023 				  "tx err %d\n", entry->urb->status);
1024 			break;
1025 		}
1026 	}
1027 
1028 	usb_autopm_put_interface_async(dev->intf);
1029 	urb->dev = NULL;
1030 	entry->state = tx_done;
1031 	defer_bh(dev, skb, &dev->txq);
1032 }
1033 
1034 /*-------------------------------------------------------------------------*/
1035 
1036 void usbnet_tx_timeout (struct net_device *net)
1037 {
1038 	struct usbnet		*dev = netdev_priv(net);
1039 
1040 	unlink_urbs (dev, &dev->txq);
1041 	tasklet_schedule (&dev->bh);
1042 
1043 	// FIXME: device recovery -- reset?
1044 }
1045 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1046 
1047 /*-------------------------------------------------------------------------*/
1048 
1049 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1050 				     struct net_device *net)
1051 {
1052 	struct usbnet		*dev = netdev_priv(net);
1053 	int			length;
1054 	struct urb		*urb = NULL;
1055 	struct skb_data		*entry;
1056 	struct driver_info	*info = dev->driver_info;
1057 	unsigned long		flags;
1058 	int retval;
1059 
1060 	if (skb)
1061 		skb_tx_timestamp(skb);
1062 
1063 	// some devices want funky USB-level framing, for
1064 	// win32 driver (usually) and/or hardware quirks
1065 	if (info->tx_fixup) {
1066 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1067 		if (!skb) {
1068 			if (netif_msg_tx_err(dev)) {
1069 				netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1070 				goto drop;
1071 			} else {
1072 				/* cdc_ncm collected packet; waits for more */
1073 				goto not_drop;
1074 			}
1075 		}
1076 	}
1077 	length = skb->len;
1078 
1079 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1080 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1081 		goto drop;
1082 	}
1083 
1084 	entry = (struct skb_data *) skb->cb;
1085 	entry->urb = urb;
1086 	entry->dev = dev;
1087 	entry->state = tx_start;
1088 	entry->length = length;
1089 
1090 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1091 			skb->data, skb->len, tx_complete, skb);
1092 
1093 	/* don't assume the hardware handles USB_ZERO_PACKET
1094 	 * NOTE:  strictly conforming cdc-ether devices should expect
1095 	 * the ZLP here, but ignore the one-byte packet.
1096 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1097 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1098 	 * packet itself if needed.
1099 	 */
1100 	if (length % dev->maxpacket == 0) {
1101 		if (!(info->flags & FLAG_SEND_ZLP)) {
1102 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1103 				urb->transfer_buffer_length++;
1104 				if (skb_tailroom(skb)) {
1105 					skb->data[skb->len] = 0;
1106 					__skb_put(skb, 1);
1107 				}
1108 			}
1109 		} else
1110 			urb->transfer_flags |= URB_ZERO_PACKET;
1111 	}
1112 
1113 	spin_lock_irqsave(&dev->txq.lock, flags);
1114 	retval = usb_autopm_get_interface_async(dev->intf);
1115 	if (retval < 0) {
1116 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1117 		goto drop;
1118 	}
1119 
1120 #ifdef CONFIG_PM
1121 	/* if this triggers the device is still a sleep */
1122 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1123 		/* transmission will be done in resume */
1124 		usb_anchor_urb(urb, &dev->deferred);
1125 		/* no use to process more packets */
1126 		netif_stop_queue(net);
1127 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1128 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1129 		goto deferred;
1130 	}
1131 #endif
1132 
1133 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1134 	case -EPIPE:
1135 		netif_stop_queue (net);
1136 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1137 		usb_autopm_put_interface_async(dev->intf);
1138 		break;
1139 	default:
1140 		usb_autopm_put_interface_async(dev->intf);
1141 		netif_dbg(dev, tx_err, dev->net,
1142 			  "tx: submit urb err %d\n", retval);
1143 		break;
1144 	case 0:
1145 		net->trans_start = jiffies;
1146 		__skb_queue_tail (&dev->txq, skb);
1147 		if (dev->txq.qlen >= TX_QLEN (dev))
1148 			netif_stop_queue (net);
1149 	}
1150 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1151 
1152 	if (retval) {
1153 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1154 drop:
1155 		dev->net->stats.tx_dropped++;
1156 not_drop:
1157 		if (skb)
1158 			dev_kfree_skb_any (skb);
1159 		usb_free_urb (urb);
1160 	} else
1161 		netif_dbg(dev, tx_queued, dev->net,
1162 			  "> tx, len %d, type 0x%x\n", length, skb->protocol);
1163 #ifdef CONFIG_PM
1164 deferred:
1165 #endif
1166 	return NETDEV_TX_OK;
1167 }
1168 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1169 
1170 /*-------------------------------------------------------------------------*/
1171 
1172 // tasklet (work deferred from completions, in_irq) or timer
1173 
1174 static void usbnet_bh (unsigned long param)
1175 {
1176 	struct usbnet		*dev = (struct usbnet *) param;
1177 	struct sk_buff		*skb;
1178 	struct skb_data		*entry;
1179 
1180 	while ((skb = skb_dequeue (&dev->done))) {
1181 		entry = (struct skb_data *) skb->cb;
1182 		switch (entry->state) {
1183 		case rx_done:
1184 			entry->state = rx_cleanup;
1185 			rx_process (dev, skb);
1186 			continue;
1187 		case tx_done:
1188 		case rx_cleanup:
1189 			usb_free_urb (entry->urb);
1190 			dev_kfree_skb (skb);
1191 			continue;
1192 		default:
1193 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1194 		}
1195 	}
1196 
1197 	// waiting for all pending urbs to complete?
1198 	if (dev->wait) {
1199 		if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
1200 			wake_up (dev->wait);
1201 		}
1202 
1203 	// or are we maybe short a few urbs?
1204 	} else if (netif_running (dev->net) &&
1205 		   netif_device_present (dev->net) &&
1206 		   !timer_pending (&dev->delay) &&
1207 		   !test_bit (EVENT_RX_HALT, &dev->flags)) {
1208 		int	temp = dev->rxq.qlen;
1209 		int	qlen = RX_QLEN (dev);
1210 
1211 		if (temp < qlen) {
1212 			struct urb	*urb;
1213 			int		i;
1214 
1215 			// don't refill the queue all at once
1216 			for (i = 0; i < 10 && dev->rxq.qlen < qlen; i++) {
1217 				urb = usb_alloc_urb (0, GFP_ATOMIC);
1218 				if (urb != NULL) {
1219 					if (rx_submit (dev, urb, GFP_ATOMIC) ==
1220 					    -ENOLINK)
1221 						return;
1222 				}
1223 			}
1224 			if (temp != dev->rxq.qlen)
1225 				netif_dbg(dev, link, dev->net,
1226 					  "rxqlen %d --> %d\n",
1227 					  temp, dev->rxq.qlen);
1228 			if (dev->rxq.qlen < qlen)
1229 				tasklet_schedule (&dev->bh);
1230 		}
1231 		if (dev->txq.qlen < TX_QLEN (dev))
1232 			netif_wake_queue (dev->net);
1233 	}
1234 }
1235 
1236 
1237 /*-------------------------------------------------------------------------
1238  *
1239  * USB Device Driver support
1240  *
1241  *-------------------------------------------------------------------------*/
1242 
1243 // precondition: never called in_interrupt
1244 
1245 void usbnet_disconnect (struct usb_interface *intf)
1246 {
1247 	struct usbnet		*dev;
1248 	struct usb_device	*xdev;
1249 	struct net_device	*net;
1250 
1251 	dev = usb_get_intfdata(intf);
1252 	usb_set_intfdata(intf, NULL);
1253 	if (!dev)
1254 		return;
1255 
1256 	xdev = interface_to_usbdev (intf);
1257 
1258 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1259 		   intf->dev.driver->name,
1260 		   xdev->bus->bus_name, xdev->devpath,
1261 		   dev->driver_info->description);
1262 
1263 	net = dev->net;
1264 	unregister_netdev (net);
1265 
1266 	cancel_work_sync(&dev->kevent);
1267 
1268 	if (dev->driver_info->unbind)
1269 		dev->driver_info->unbind (dev, intf);
1270 
1271 	usb_kill_urb(dev->interrupt);
1272 	usb_free_urb(dev->interrupt);
1273 
1274 	free_netdev(net);
1275 	usb_put_dev (xdev);
1276 }
1277 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1278 
1279 static const struct net_device_ops usbnet_netdev_ops = {
1280 	.ndo_open		= usbnet_open,
1281 	.ndo_stop		= usbnet_stop,
1282 	.ndo_start_xmit		= usbnet_start_xmit,
1283 	.ndo_tx_timeout		= usbnet_tx_timeout,
1284 	.ndo_change_mtu		= usbnet_change_mtu,
1285 	.ndo_set_mac_address 	= eth_mac_addr,
1286 	.ndo_validate_addr	= eth_validate_addr,
1287 };
1288 
1289 /*-------------------------------------------------------------------------*/
1290 
1291 // precondition: never called in_interrupt
1292 
1293 static struct device_type wlan_type = {
1294 	.name	= "wlan",
1295 };
1296 
1297 static struct device_type wwan_type = {
1298 	.name	= "wwan",
1299 };
1300 
1301 int
1302 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1303 {
1304 	struct usbnet			*dev;
1305 	struct net_device		*net;
1306 	struct usb_host_interface	*interface;
1307 	struct driver_info		*info;
1308 	struct usb_device		*xdev;
1309 	int				status;
1310 	const char			*name;
1311 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1312 
1313 	/* usbnet already took usb runtime pm, so have to enable the feature
1314 	 * for usb interface, otherwise usb_autopm_get_interface may return
1315 	 * failure if USB_SUSPEND(RUNTIME_PM) is enabled.
1316 	 */
1317 	if (!driver->supports_autosuspend) {
1318 		driver->supports_autosuspend = 1;
1319 		pm_runtime_enable(&udev->dev);
1320 	}
1321 
1322 	name = udev->dev.driver->name;
1323 	info = (struct driver_info *) prod->driver_info;
1324 	if (!info) {
1325 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1326 		return -ENODEV;
1327 	}
1328 	xdev = interface_to_usbdev (udev);
1329 	interface = udev->cur_altsetting;
1330 
1331 	usb_get_dev (xdev);
1332 
1333 	status = -ENOMEM;
1334 
1335 	// set up our own records
1336 	net = alloc_etherdev(sizeof(*dev));
1337 	if (!net) {
1338 		dbg ("can't kmalloc dev");
1339 		goto out;
1340 	}
1341 
1342 	/* netdev_printk() needs this so do it as early as possible */
1343 	SET_NETDEV_DEV(net, &udev->dev);
1344 
1345 	dev = netdev_priv(net);
1346 	dev->udev = xdev;
1347 	dev->intf = udev;
1348 	dev->driver_info = info;
1349 	dev->driver_name = name;
1350 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1351 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1352 	skb_queue_head_init (&dev->rxq);
1353 	skb_queue_head_init (&dev->txq);
1354 	skb_queue_head_init (&dev->done);
1355 	skb_queue_head_init(&dev->rxq_pause);
1356 	dev->bh.func = usbnet_bh;
1357 	dev->bh.data = (unsigned long) dev;
1358 	INIT_WORK (&dev->kevent, kevent);
1359 	init_usb_anchor(&dev->deferred);
1360 	dev->delay.function = usbnet_bh;
1361 	dev->delay.data = (unsigned long) dev;
1362 	init_timer (&dev->delay);
1363 	mutex_init (&dev->phy_mutex);
1364 
1365 	dev->net = net;
1366 	strcpy (net->name, "usb%d");
1367 	memcpy (net->dev_addr, node_id, sizeof node_id);
1368 
1369 	/* rx and tx sides can use different message sizes;
1370 	 * bind() should set rx_urb_size in that case.
1371 	 */
1372 	dev->hard_mtu = net->mtu + net->hard_header_len;
1373 #if 0
1374 // dma_supported() is deeply broken on almost all architectures
1375 	// possible with some EHCI controllers
1376 	if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1377 		net->features |= NETIF_F_HIGHDMA;
1378 #endif
1379 
1380 	net->netdev_ops = &usbnet_netdev_ops;
1381 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1382 	net->ethtool_ops = &usbnet_ethtool_ops;
1383 
1384 	// allow device-specific bind/init procedures
1385 	// NOTE net->name still not usable ...
1386 	if (info->bind) {
1387 		status = info->bind (dev, udev);
1388 		if (status < 0)
1389 			goto out1;
1390 
1391 		// heuristic:  "usb%d" for links we know are two-host,
1392 		// else "eth%d" when there's reasonable doubt.  userspace
1393 		// can rename the link if it knows better.
1394 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1395 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1396 		     (net->dev_addr [0] & 0x02) == 0))
1397 			strcpy (net->name, "eth%d");
1398 		/* WLAN devices should always be named "wlan%d" */
1399 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1400 			strcpy(net->name, "wlan%d");
1401 		/* WWAN devices should always be named "wwan%d" */
1402 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1403 			strcpy(net->name, "wwan%d");
1404 
1405 		/* maybe the remote can't receive an Ethernet MTU */
1406 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1407 			net->mtu = dev->hard_mtu - net->hard_header_len;
1408 	} else if (!info->in || !info->out)
1409 		status = usbnet_get_endpoints (dev, udev);
1410 	else {
1411 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1412 		dev->out = usb_sndbulkpipe (xdev, info->out);
1413 		if (!(info->flags & FLAG_NO_SETINT))
1414 			status = usb_set_interface (xdev,
1415 				interface->desc.bInterfaceNumber,
1416 				interface->desc.bAlternateSetting);
1417 		else
1418 			status = 0;
1419 
1420 	}
1421 	if (status >= 0 && dev->status)
1422 		status = init_status (dev, udev);
1423 	if (status < 0)
1424 		goto out3;
1425 
1426 	if (!dev->rx_urb_size)
1427 		dev->rx_urb_size = dev->hard_mtu;
1428 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1429 
1430 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1431 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1432 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1433 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1434 
1435 	status = register_netdev (net);
1436 	if (status)
1437 		goto out3;
1438 	netif_info(dev, probe, dev->net,
1439 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1440 		   udev->dev.driver->name,
1441 		   xdev->bus->bus_name, xdev->devpath,
1442 		   dev->driver_info->description,
1443 		   net->dev_addr);
1444 
1445 	// ok, it's ready to go.
1446 	usb_set_intfdata (udev, dev);
1447 
1448 	netif_device_attach (net);
1449 
1450 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1451 		netif_carrier_off(net);
1452 
1453 	return 0;
1454 
1455 out3:
1456 	if (info->unbind)
1457 		info->unbind (dev, udev);
1458 out1:
1459 	free_netdev(net);
1460 out:
1461 	usb_put_dev(xdev);
1462 	return status;
1463 }
1464 EXPORT_SYMBOL_GPL(usbnet_probe);
1465 
1466 /*-------------------------------------------------------------------------*/
1467 
1468 /*
1469  * suspend the whole driver as soon as the first interface is suspended
1470  * resume only when the last interface is resumed
1471  */
1472 
1473 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1474 {
1475 	struct usbnet		*dev = usb_get_intfdata(intf);
1476 
1477 	if (!dev->suspend_count++) {
1478 		spin_lock_irq(&dev->txq.lock);
1479 		/* don't autosuspend while transmitting */
1480 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1481 			spin_unlock_irq(&dev->txq.lock);
1482 			return -EBUSY;
1483 		} else {
1484 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1485 			spin_unlock_irq(&dev->txq.lock);
1486 		}
1487 		/*
1488 		 * accelerate emptying of the rx and queues, to avoid
1489 		 * having everything error out.
1490 		 */
1491 		netif_device_detach (dev->net);
1492 		usbnet_terminate_urbs(dev);
1493 		usb_kill_urb(dev->interrupt);
1494 
1495 		/*
1496 		 * reattach so runtime management can use and
1497 		 * wake the device
1498 		 */
1499 		netif_device_attach (dev->net);
1500 	}
1501 	return 0;
1502 }
1503 EXPORT_SYMBOL_GPL(usbnet_suspend);
1504 
1505 int usbnet_resume (struct usb_interface *intf)
1506 {
1507 	struct usbnet		*dev = usb_get_intfdata(intf);
1508 	struct sk_buff          *skb;
1509 	struct urb              *res;
1510 	int                     retval;
1511 
1512 	if (!--dev->suspend_count) {
1513 		/* resume interrupt URBs */
1514 		if (dev->interrupt && test_bit(EVENT_DEV_OPEN, &dev->flags))
1515 			usb_submit_urb(dev->interrupt, GFP_NOIO);
1516 
1517 		spin_lock_irq(&dev->txq.lock);
1518 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1519 
1520 			skb = (struct sk_buff *)res->context;
1521 			retval = usb_submit_urb(res, GFP_ATOMIC);
1522 			if (retval < 0) {
1523 				dev_kfree_skb_any(skb);
1524 				usb_free_urb(res);
1525 				usb_autopm_put_interface_async(dev->intf);
1526 			} else {
1527 				dev->net->trans_start = jiffies;
1528 				__skb_queue_tail(&dev->txq, skb);
1529 			}
1530 		}
1531 
1532 		smp_mb();
1533 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1534 		spin_unlock_irq(&dev->txq.lock);
1535 
1536 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1537 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1538 				netif_start_queue(dev->net);
1539 			tasklet_schedule (&dev->bh);
1540 		}
1541 	}
1542 	return 0;
1543 }
1544 EXPORT_SYMBOL_GPL(usbnet_resume);
1545 
1546 
1547 /*-------------------------------------------------------------------------*/
1548 
1549 static int __init usbnet_init(void)
1550 {
1551 	/* Compiler should optimize this out. */
1552 	BUILD_BUG_ON(
1553 		FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
1554 
1555 	random_ether_addr(node_id);
1556 	return 0;
1557 }
1558 module_init(usbnet_init);
1559 
1560 static void __exit usbnet_exit(void)
1561 {
1562 }
1563 module_exit(usbnet_exit);
1564 
1565 MODULE_AUTHOR("David Brownell");
1566 MODULE_DESCRIPTION("USB network driver framework");
1567 MODULE_LICENSE("GPL");
1568