xref: /linux/drivers/net/usb/usbnet.c (revision 8a5617bdc111aa7ba49c81fa694fde63d3474f94)
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 		/* With RX_ASSEMBLE, rx_fixup() must update counters */
392 		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
393 			dev->net->stats.rx_errors++;
394 		goto done;
395 	}
396 	// else network stack removes extra byte if we forced a short packet
397 
398 	if (skb->len) {
399 		/* all data was already cloned from skb inside the driver */
400 		if (dev->driver_info->flags & FLAG_MULTI_PACKET)
401 			dev_kfree_skb_any(skb);
402 		else
403 			usbnet_skb_return(dev, skb);
404 		return;
405 	}
406 
407 	netif_dbg(dev, rx_err, dev->net, "drop\n");
408 	dev->net->stats.rx_errors++;
409 done:
410 	skb_queue_tail(&dev->done, skb);
411 }
412 
413 /*-------------------------------------------------------------------------*/
414 
415 static void rx_complete (struct urb *urb)
416 {
417 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
418 	struct skb_data		*entry = (struct skb_data *) skb->cb;
419 	struct usbnet		*dev = entry->dev;
420 	int			urb_status = urb->status;
421 
422 	skb_put (skb, urb->actual_length);
423 	entry->state = rx_done;
424 	entry->urb = NULL;
425 
426 	switch (urb_status) {
427 	/* success */
428 	case 0:
429 		if (skb->len < dev->net->hard_header_len) {
430 			entry->state = rx_cleanup;
431 			dev->net->stats.rx_errors++;
432 			dev->net->stats.rx_length_errors++;
433 			netif_dbg(dev, rx_err, dev->net,
434 				  "rx length %d\n", skb->len);
435 		}
436 		break;
437 
438 	/* stalls need manual reset. this is rare ... except that
439 	 * when going through USB 2.0 TTs, unplug appears this way.
440 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
441 	 * storm, recovering as needed.
442 	 */
443 	case -EPIPE:
444 		dev->net->stats.rx_errors++;
445 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
446 		// FALLTHROUGH
447 
448 	/* software-driven interface shutdown */
449 	case -ECONNRESET:		/* async unlink */
450 	case -ESHUTDOWN:		/* hardware gone */
451 		netif_dbg(dev, ifdown, dev->net,
452 			  "rx shutdown, code %d\n", urb_status);
453 		goto block;
454 
455 	/* we get controller i/o faults during khubd disconnect() delays.
456 	 * throttle down resubmits, to avoid log floods; just temporarily,
457 	 * so we still recover when the fault isn't a khubd delay.
458 	 */
459 	case -EPROTO:
460 	case -ETIME:
461 	case -EILSEQ:
462 		dev->net->stats.rx_errors++;
463 		if (!timer_pending (&dev->delay)) {
464 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
465 			netif_dbg(dev, link, dev->net,
466 				  "rx throttle %d\n", urb_status);
467 		}
468 block:
469 		entry->state = rx_cleanup;
470 		entry->urb = urb;
471 		urb = NULL;
472 		break;
473 
474 	/* data overrun ... flush fifo? */
475 	case -EOVERFLOW:
476 		dev->net->stats.rx_over_errors++;
477 		// FALLTHROUGH
478 
479 	default:
480 		entry->state = rx_cleanup;
481 		dev->net->stats.rx_errors++;
482 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
483 		break;
484 	}
485 
486 	defer_bh(dev, skb, &dev->rxq);
487 
488 	if (urb) {
489 		if (netif_running (dev->net) &&
490 		    !test_bit (EVENT_RX_HALT, &dev->flags)) {
491 			rx_submit (dev, urb, GFP_ATOMIC);
492 			return;
493 		}
494 		usb_free_urb (urb);
495 	}
496 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
497 }
498 
499 static void intr_complete (struct urb *urb)
500 {
501 	struct usbnet	*dev = urb->context;
502 	int		status = urb->status;
503 
504 	switch (status) {
505 	/* success */
506 	case 0:
507 		dev->driver_info->status(dev, urb);
508 		break;
509 
510 	/* software-driven interface shutdown */
511 	case -ENOENT:		/* urb killed */
512 	case -ESHUTDOWN:	/* hardware gone */
513 		netif_dbg(dev, ifdown, dev->net,
514 			  "intr shutdown, code %d\n", status);
515 		return;
516 
517 	/* NOTE:  not throttling like RX/TX, since this endpoint
518 	 * already polls infrequently
519 	 */
520 	default:
521 		netdev_dbg(dev->net, "intr status %d\n", status);
522 		break;
523 	}
524 
525 	if (!netif_running (dev->net))
526 		return;
527 
528 	memset(urb->transfer_buffer, 0, urb->transfer_buffer_length);
529 	status = usb_submit_urb (urb, GFP_ATOMIC);
530 	if (status != 0)
531 		netif_err(dev, timer, dev->net,
532 			  "intr resubmit --> %d\n", status);
533 }
534 
535 /*-------------------------------------------------------------------------*/
536 void usbnet_pause_rx(struct usbnet *dev)
537 {
538 	set_bit(EVENT_RX_PAUSED, &dev->flags);
539 
540 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
541 }
542 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
543 
544 void usbnet_resume_rx(struct usbnet *dev)
545 {
546 	struct sk_buff *skb;
547 	int num = 0;
548 
549 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
550 
551 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
552 		usbnet_skb_return(dev, skb);
553 		num++;
554 	}
555 
556 	tasklet_schedule(&dev->bh);
557 
558 	netif_dbg(dev, rx_status, dev->net,
559 		  "paused rx queue disabled, %d skbs requeued\n", num);
560 }
561 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
562 
563 void usbnet_purge_paused_rxq(struct usbnet *dev)
564 {
565 	skb_queue_purge(&dev->rxq_pause);
566 }
567 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
568 
569 /*-------------------------------------------------------------------------*/
570 
571 // unlink pending rx/tx; completion handlers do all other cleanup
572 
573 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
574 {
575 	unsigned long		flags;
576 	struct sk_buff		*skb, *skbnext;
577 	int			count = 0;
578 
579 	spin_lock_irqsave (&q->lock, flags);
580 	skb_queue_walk_safe(q, skb, skbnext) {
581 		struct skb_data		*entry;
582 		struct urb		*urb;
583 		int			retval;
584 
585 		entry = (struct skb_data *) skb->cb;
586 		urb = entry->urb;
587 
588 		// during some PM-driven resume scenarios,
589 		// these (async) unlinks complete immediately
590 		retval = usb_unlink_urb (urb);
591 		if (retval != -EINPROGRESS && retval != 0)
592 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
593 		else
594 			count++;
595 	}
596 	spin_unlock_irqrestore (&q->lock, flags);
597 	return count;
598 }
599 
600 // Flush all pending rx urbs
601 // minidrivers may need to do this when the MTU changes
602 
603 void usbnet_unlink_rx_urbs(struct usbnet *dev)
604 {
605 	if (netif_running(dev->net)) {
606 		(void) unlink_urbs (dev, &dev->rxq);
607 		tasklet_schedule(&dev->bh);
608 	}
609 }
610 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
611 
612 /*-------------------------------------------------------------------------*/
613 
614 // precondition: never called in_interrupt
615 static void usbnet_terminate_urbs(struct usbnet *dev)
616 {
617 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
618 	DECLARE_WAITQUEUE(wait, current);
619 	int temp;
620 
621 	/* ensure there are no more active urbs */
622 	add_wait_queue(&unlink_wakeup, &wait);
623 	set_current_state(TASK_UNINTERRUPTIBLE);
624 	dev->wait = &unlink_wakeup;
625 	temp = unlink_urbs(dev, &dev->txq) +
626 		unlink_urbs(dev, &dev->rxq);
627 
628 	/* maybe wait for deletions to finish. */
629 	while (!skb_queue_empty(&dev->rxq)
630 		&& !skb_queue_empty(&dev->txq)
631 		&& !skb_queue_empty(&dev->done)) {
632 			schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
633 			set_current_state(TASK_UNINTERRUPTIBLE);
634 			netif_dbg(dev, ifdown, dev->net,
635 				  "waited for %d urb completions\n", temp);
636 	}
637 	set_current_state(TASK_RUNNING);
638 	dev->wait = NULL;
639 	remove_wait_queue(&unlink_wakeup, &wait);
640 }
641 
642 int usbnet_stop (struct net_device *net)
643 {
644 	struct usbnet		*dev = netdev_priv(net);
645 	struct driver_info	*info = dev->driver_info;
646 	int			retval;
647 
648 	netif_stop_queue (net);
649 
650 	netif_info(dev, ifdown, dev->net,
651 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
652 		   net->stats.rx_packets, net->stats.tx_packets,
653 		   net->stats.rx_errors, net->stats.tx_errors);
654 
655 	/* allow minidriver to stop correctly (wireless devices to turn off
656 	 * radio etc) */
657 	if (info->stop) {
658 		retval = info->stop(dev);
659 		if (retval < 0)
660 			netif_info(dev, ifdown, dev->net,
661 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
662 				   retval,
663 				   dev->udev->bus->bus_name, dev->udev->devpath,
664 				   info->description);
665 	}
666 
667 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
668 		usbnet_terminate_urbs(dev);
669 
670 	usb_kill_urb(dev->interrupt);
671 
672 	usbnet_purge_paused_rxq(dev);
673 
674 	/* deferred work (task, timer, softirq) must also stop.
675 	 * can't flush_scheduled_work() until we drop rtnl (later),
676 	 * else workers could deadlock; so make workers a NOP.
677 	 */
678 	dev->flags = 0;
679 	del_timer_sync (&dev->delay);
680 	tasklet_kill (&dev->bh);
681 	if (info->manage_power)
682 		info->manage_power(dev, 0);
683 	else
684 		usb_autopm_put_interface(dev->intf);
685 
686 	return 0;
687 }
688 EXPORT_SYMBOL_GPL(usbnet_stop);
689 
690 /*-------------------------------------------------------------------------*/
691 
692 // posts reads, and enables write queuing
693 
694 // precondition: never called in_interrupt
695 
696 int usbnet_open (struct net_device *net)
697 {
698 	struct usbnet		*dev = netdev_priv(net);
699 	int			retval;
700 	struct driver_info	*info = dev->driver_info;
701 
702 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
703 		netif_info(dev, ifup, dev->net,
704 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
705 			   retval,
706 			   dev->udev->bus->bus_name,
707 			   dev->udev->devpath,
708 			   info->description);
709 		goto done_nopm;
710 	}
711 
712 	// put into "known safe" state
713 	if (info->reset && (retval = info->reset (dev)) < 0) {
714 		netif_info(dev, ifup, dev->net,
715 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
716 			   retval,
717 			   dev->udev->bus->bus_name,
718 			   dev->udev->devpath,
719 			   info->description);
720 		goto done;
721 	}
722 
723 	// insist peer be connected
724 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
725 		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
726 		goto done;
727 	}
728 
729 	/* start any status interrupt transfer */
730 	if (dev->interrupt) {
731 		retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
732 		if (retval < 0) {
733 			netif_err(dev, ifup, dev->net,
734 				  "intr submit %d\n", retval);
735 			goto done;
736 		}
737 	}
738 
739 	set_bit(EVENT_DEV_OPEN, &dev->flags);
740 	netif_start_queue (net);
741 	netif_info(dev, ifup, dev->net,
742 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
743 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
744 		   dev->net->mtu,
745 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
746 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
747 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
748 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
749 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
750 		   "simple");
751 
752 	// delay posting reads until we're fully open
753 	tasklet_schedule (&dev->bh);
754 	if (info->manage_power) {
755 		retval = info->manage_power(dev, 1);
756 		if (retval < 0)
757 			goto done;
758 		usb_autopm_put_interface(dev->intf);
759 	}
760 	return retval;
761 
762 done:
763 	usb_autopm_put_interface(dev->intf);
764 done_nopm:
765 	return retval;
766 }
767 EXPORT_SYMBOL_GPL(usbnet_open);
768 
769 /*-------------------------------------------------------------------------*/
770 
771 /* ethtool methods; minidrivers may need to add some more, but
772  * they'll probably want to use this base set.
773  */
774 
775 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
776 {
777 	struct usbnet *dev = netdev_priv(net);
778 
779 	if (!dev->mii.mdio_read)
780 		return -EOPNOTSUPP;
781 
782 	return mii_ethtool_gset(&dev->mii, cmd);
783 }
784 EXPORT_SYMBOL_GPL(usbnet_get_settings);
785 
786 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
787 {
788 	struct usbnet *dev = netdev_priv(net);
789 	int retval;
790 
791 	if (!dev->mii.mdio_write)
792 		return -EOPNOTSUPP;
793 
794 	retval = mii_ethtool_sset(&dev->mii, cmd);
795 
796 	/* link speed/duplex might have changed */
797 	if (dev->driver_info->link_reset)
798 		dev->driver_info->link_reset(dev);
799 
800 	return retval;
801 
802 }
803 EXPORT_SYMBOL_GPL(usbnet_set_settings);
804 
805 u32 usbnet_get_link (struct net_device *net)
806 {
807 	struct usbnet *dev = netdev_priv(net);
808 
809 	/* If a check_connect is defined, return its result */
810 	if (dev->driver_info->check_connect)
811 		return dev->driver_info->check_connect (dev) == 0;
812 
813 	/* if the device has mii operations, use those */
814 	if (dev->mii.mdio_read)
815 		return mii_link_ok(&dev->mii);
816 
817 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
818 	return ethtool_op_get_link(net);
819 }
820 EXPORT_SYMBOL_GPL(usbnet_get_link);
821 
822 int usbnet_nway_reset(struct net_device *net)
823 {
824 	struct usbnet *dev = netdev_priv(net);
825 
826 	if (!dev->mii.mdio_write)
827 		return -EOPNOTSUPP;
828 
829 	return mii_nway_restart(&dev->mii);
830 }
831 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
832 
833 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
834 {
835 	struct usbnet *dev = netdev_priv(net);
836 
837 	strncpy (info->driver, dev->driver_name, sizeof info->driver);
838 	strncpy (info->version, DRIVER_VERSION, sizeof info->version);
839 	strncpy (info->fw_version, dev->driver_info->description,
840 		sizeof info->fw_version);
841 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
842 }
843 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
844 
845 u32 usbnet_get_msglevel (struct net_device *net)
846 {
847 	struct usbnet *dev = netdev_priv(net);
848 
849 	return dev->msg_enable;
850 }
851 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
852 
853 void usbnet_set_msglevel (struct net_device *net, u32 level)
854 {
855 	struct usbnet *dev = netdev_priv(net);
856 
857 	dev->msg_enable = level;
858 }
859 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
860 
861 /* drivers may override default ethtool_ops in their bind() routine */
862 static const struct ethtool_ops usbnet_ethtool_ops = {
863 	.get_settings		= usbnet_get_settings,
864 	.set_settings		= usbnet_set_settings,
865 	.get_link		= usbnet_get_link,
866 	.nway_reset		= usbnet_nway_reset,
867 	.get_drvinfo		= usbnet_get_drvinfo,
868 	.get_msglevel		= usbnet_get_msglevel,
869 	.set_msglevel		= usbnet_set_msglevel,
870 };
871 
872 /*-------------------------------------------------------------------------*/
873 
874 /* work that cannot be done in interrupt context uses keventd.
875  *
876  * NOTE:  with 2.5 we could do more of this using completion callbacks,
877  * especially now that control transfers can be queued.
878  */
879 static void
880 kevent (struct work_struct *work)
881 {
882 	struct usbnet		*dev =
883 		container_of(work, struct usbnet, kevent);
884 	int			status;
885 
886 	/* usb_clear_halt() needs a thread context */
887 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
888 		unlink_urbs (dev, &dev->txq);
889 		status = usb_autopm_get_interface(dev->intf);
890 		if (status < 0)
891 			goto fail_pipe;
892 		status = usb_clear_halt (dev->udev, dev->out);
893 		usb_autopm_put_interface(dev->intf);
894 		if (status < 0 &&
895 		    status != -EPIPE &&
896 		    status != -ESHUTDOWN) {
897 			if (netif_msg_tx_err (dev))
898 fail_pipe:
899 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
900 					   status);
901 		} else {
902 			clear_bit (EVENT_TX_HALT, &dev->flags);
903 			if (status != -ESHUTDOWN)
904 				netif_wake_queue (dev->net);
905 		}
906 	}
907 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
908 		unlink_urbs (dev, &dev->rxq);
909 		status = usb_autopm_get_interface(dev->intf);
910 		if (status < 0)
911 			goto fail_halt;
912 		status = usb_clear_halt (dev->udev, dev->in);
913 		usb_autopm_put_interface(dev->intf);
914 		if (status < 0 &&
915 		    status != -EPIPE &&
916 		    status != -ESHUTDOWN) {
917 			if (netif_msg_rx_err (dev))
918 fail_halt:
919 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
920 					   status);
921 		} else {
922 			clear_bit (EVENT_RX_HALT, &dev->flags);
923 			tasklet_schedule (&dev->bh);
924 		}
925 	}
926 
927 	/* tasklet could resubmit itself forever if memory is tight */
928 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
929 		struct urb	*urb = NULL;
930 		int resched = 1;
931 
932 		if (netif_running (dev->net))
933 			urb = usb_alloc_urb (0, GFP_KERNEL);
934 		else
935 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
936 		if (urb != NULL) {
937 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
938 			status = usb_autopm_get_interface(dev->intf);
939 			if (status < 0) {
940 				usb_free_urb(urb);
941 				goto fail_lowmem;
942 			}
943 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
944 				resched = 0;
945 			usb_autopm_put_interface(dev->intf);
946 fail_lowmem:
947 			if (resched)
948 				tasklet_schedule (&dev->bh);
949 		}
950 	}
951 
952 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
953 		struct driver_info	*info = dev->driver_info;
954 		int			retval = 0;
955 
956 		clear_bit (EVENT_LINK_RESET, &dev->flags);
957 		status = usb_autopm_get_interface(dev->intf);
958 		if (status < 0)
959 			goto skip_reset;
960 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
961 			usb_autopm_put_interface(dev->intf);
962 skip_reset:
963 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
964 				    retval,
965 				    dev->udev->bus->bus_name,
966 				    dev->udev->devpath,
967 				    info->description);
968 		} else {
969 			usb_autopm_put_interface(dev->intf);
970 		}
971 	}
972 
973 	if (dev->flags)
974 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
975 }
976 
977 /*-------------------------------------------------------------------------*/
978 
979 static void tx_complete (struct urb *urb)
980 {
981 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
982 	struct skb_data		*entry = (struct skb_data *) skb->cb;
983 	struct usbnet		*dev = entry->dev;
984 
985 	if (urb->status == 0) {
986 		if (!(dev->driver_info->flags & FLAG_MULTI_PACKET))
987 			dev->net->stats.tx_packets++;
988 		dev->net->stats.tx_bytes += entry->length;
989 	} else {
990 		dev->net->stats.tx_errors++;
991 
992 		switch (urb->status) {
993 		case -EPIPE:
994 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
995 			break;
996 
997 		/* software-driven interface shutdown */
998 		case -ECONNRESET:		// async unlink
999 		case -ESHUTDOWN:		// hardware gone
1000 			break;
1001 
1002 		// like rx, tx gets controller i/o faults during khubd delays
1003 		// and so it uses the same throttling mechanism.
1004 		case -EPROTO:
1005 		case -ETIME:
1006 		case -EILSEQ:
1007 			usb_mark_last_busy(dev->udev);
1008 			if (!timer_pending (&dev->delay)) {
1009 				mod_timer (&dev->delay,
1010 					jiffies + THROTTLE_JIFFIES);
1011 				netif_dbg(dev, link, dev->net,
1012 					  "tx throttle %d\n", urb->status);
1013 			}
1014 			netif_stop_queue (dev->net);
1015 			break;
1016 		default:
1017 			netif_dbg(dev, tx_err, dev->net,
1018 				  "tx err %d\n", entry->urb->status);
1019 			break;
1020 		}
1021 	}
1022 
1023 	usb_autopm_put_interface_async(dev->intf);
1024 	urb->dev = NULL;
1025 	entry->state = tx_done;
1026 	defer_bh(dev, skb, &dev->txq);
1027 }
1028 
1029 /*-------------------------------------------------------------------------*/
1030 
1031 void usbnet_tx_timeout (struct net_device *net)
1032 {
1033 	struct usbnet		*dev = netdev_priv(net);
1034 
1035 	unlink_urbs (dev, &dev->txq);
1036 	tasklet_schedule (&dev->bh);
1037 
1038 	// FIXME: device recovery -- reset?
1039 }
1040 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1041 
1042 /*-------------------------------------------------------------------------*/
1043 
1044 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1045 				     struct net_device *net)
1046 {
1047 	struct usbnet		*dev = netdev_priv(net);
1048 	int			length;
1049 	struct urb		*urb = NULL;
1050 	struct skb_data		*entry;
1051 	struct driver_info	*info = dev->driver_info;
1052 	unsigned long		flags;
1053 	int retval;
1054 
1055 	// some devices want funky USB-level framing, for
1056 	// win32 driver (usually) and/or hardware quirks
1057 	if (info->tx_fixup) {
1058 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1059 		if (!skb) {
1060 			if (netif_msg_tx_err(dev)) {
1061 				netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1062 				goto drop;
1063 			} else {
1064 				/* cdc_ncm collected packet; waits for more */
1065 				goto not_drop;
1066 			}
1067 		}
1068 	}
1069 	length = skb->len;
1070 
1071 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1072 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1073 		goto drop;
1074 	}
1075 
1076 	entry = (struct skb_data *) skb->cb;
1077 	entry->urb = urb;
1078 	entry->dev = dev;
1079 	entry->state = tx_start;
1080 	entry->length = length;
1081 
1082 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1083 			skb->data, skb->len, tx_complete, skb);
1084 
1085 	/* don't assume the hardware handles USB_ZERO_PACKET
1086 	 * NOTE:  strictly conforming cdc-ether devices should expect
1087 	 * the ZLP here, but ignore the one-byte packet.
1088 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1089 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1090 	 * packet itself if needed.
1091 	 */
1092 	if (length % dev->maxpacket == 0) {
1093 		if (!(info->flags & FLAG_SEND_ZLP)) {
1094 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1095 				urb->transfer_buffer_length++;
1096 				if (skb_tailroom(skb)) {
1097 					skb->data[skb->len] = 0;
1098 					__skb_put(skb, 1);
1099 				}
1100 			}
1101 		} else
1102 			urb->transfer_flags |= URB_ZERO_PACKET;
1103 	}
1104 
1105 	spin_lock_irqsave(&dev->txq.lock, flags);
1106 	retval = usb_autopm_get_interface_async(dev->intf);
1107 	if (retval < 0) {
1108 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1109 		goto drop;
1110 	}
1111 
1112 #ifdef CONFIG_PM
1113 	/* if this triggers the device is still a sleep */
1114 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1115 		/* transmission will be done in resume */
1116 		usb_anchor_urb(urb, &dev->deferred);
1117 		/* no use to process more packets */
1118 		netif_stop_queue(net);
1119 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1120 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1121 		goto deferred;
1122 	}
1123 #endif
1124 
1125 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1126 	case -EPIPE:
1127 		netif_stop_queue (net);
1128 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1129 		usb_autopm_put_interface_async(dev->intf);
1130 		break;
1131 	default:
1132 		usb_autopm_put_interface_async(dev->intf);
1133 		netif_dbg(dev, tx_err, dev->net,
1134 			  "tx: submit urb err %d\n", retval);
1135 		break;
1136 	case 0:
1137 		net->trans_start = jiffies;
1138 		__skb_queue_tail (&dev->txq, skb);
1139 		if (dev->txq.qlen >= TX_QLEN (dev))
1140 			netif_stop_queue (net);
1141 	}
1142 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1143 
1144 	if (retval) {
1145 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1146 drop:
1147 		dev->net->stats.tx_dropped++;
1148 not_drop:
1149 		if (skb)
1150 			dev_kfree_skb_any (skb);
1151 		usb_free_urb (urb);
1152 	} else
1153 		netif_dbg(dev, tx_queued, dev->net,
1154 			  "> tx, len %d, type 0x%x\n", length, skb->protocol);
1155 #ifdef CONFIG_PM
1156 deferred:
1157 #endif
1158 	return NETDEV_TX_OK;
1159 }
1160 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1161 
1162 /*-------------------------------------------------------------------------*/
1163 
1164 // tasklet (work deferred from completions, in_irq) or timer
1165 
1166 static void usbnet_bh (unsigned long param)
1167 {
1168 	struct usbnet		*dev = (struct usbnet *) param;
1169 	struct sk_buff		*skb;
1170 	struct skb_data		*entry;
1171 
1172 	while ((skb = skb_dequeue (&dev->done))) {
1173 		entry = (struct skb_data *) skb->cb;
1174 		switch (entry->state) {
1175 		case rx_done:
1176 			entry->state = rx_cleanup;
1177 			rx_process (dev, skb);
1178 			continue;
1179 		case tx_done:
1180 		case rx_cleanup:
1181 			usb_free_urb (entry->urb);
1182 			dev_kfree_skb (skb);
1183 			continue;
1184 		default:
1185 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1186 		}
1187 	}
1188 
1189 	// waiting for all pending urbs to complete?
1190 	if (dev->wait) {
1191 		if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
1192 			wake_up (dev->wait);
1193 		}
1194 
1195 	// or are we maybe short a few urbs?
1196 	} else if (netif_running (dev->net) &&
1197 		   netif_device_present (dev->net) &&
1198 		   !timer_pending (&dev->delay) &&
1199 		   !test_bit (EVENT_RX_HALT, &dev->flags)) {
1200 		int	temp = dev->rxq.qlen;
1201 		int	qlen = RX_QLEN (dev);
1202 
1203 		if (temp < qlen) {
1204 			struct urb	*urb;
1205 			int		i;
1206 
1207 			// don't refill the queue all at once
1208 			for (i = 0; i < 10 && dev->rxq.qlen < qlen; i++) {
1209 				urb = usb_alloc_urb (0, GFP_ATOMIC);
1210 				if (urb != NULL) {
1211 					if (rx_submit (dev, urb, GFP_ATOMIC) ==
1212 					    -ENOLINK)
1213 						return;
1214 				}
1215 			}
1216 			if (temp != dev->rxq.qlen)
1217 				netif_dbg(dev, link, dev->net,
1218 					  "rxqlen %d --> %d\n",
1219 					  temp, dev->rxq.qlen);
1220 			if (dev->rxq.qlen < qlen)
1221 				tasklet_schedule (&dev->bh);
1222 		}
1223 		if (dev->txq.qlen < TX_QLEN (dev))
1224 			netif_wake_queue (dev->net);
1225 	}
1226 }
1227 
1228 
1229 /*-------------------------------------------------------------------------
1230  *
1231  * USB Device Driver support
1232  *
1233  *-------------------------------------------------------------------------*/
1234 
1235 // precondition: never called in_interrupt
1236 
1237 void usbnet_disconnect (struct usb_interface *intf)
1238 {
1239 	struct usbnet		*dev;
1240 	struct usb_device	*xdev;
1241 	struct net_device	*net;
1242 
1243 	dev = usb_get_intfdata(intf);
1244 	usb_set_intfdata(intf, NULL);
1245 	if (!dev)
1246 		return;
1247 
1248 	xdev = interface_to_usbdev (intf);
1249 
1250 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1251 		   intf->dev.driver->name,
1252 		   xdev->bus->bus_name, xdev->devpath,
1253 		   dev->driver_info->description);
1254 
1255 	net = dev->net;
1256 	unregister_netdev (net);
1257 
1258 	cancel_work_sync(&dev->kevent);
1259 
1260 	if (dev->driver_info->unbind)
1261 		dev->driver_info->unbind (dev, intf);
1262 
1263 	usb_kill_urb(dev->interrupt);
1264 	usb_free_urb(dev->interrupt);
1265 
1266 	free_netdev(net);
1267 	usb_put_dev (xdev);
1268 }
1269 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1270 
1271 static const struct net_device_ops usbnet_netdev_ops = {
1272 	.ndo_open		= usbnet_open,
1273 	.ndo_stop		= usbnet_stop,
1274 	.ndo_start_xmit		= usbnet_start_xmit,
1275 	.ndo_tx_timeout		= usbnet_tx_timeout,
1276 	.ndo_change_mtu		= usbnet_change_mtu,
1277 	.ndo_set_mac_address 	= eth_mac_addr,
1278 	.ndo_validate_addr	= eth_validate_addr,
1279 };
1280 
1281 /*-------------------------------------------------------------------------*/
1282 
1283 // precondition: never called in_interrupt
1284 
1285 static struct device_type wlan_type = {
1286 	.name	= "wlan",
1287 };
1288 
1289 static struct device_type wwan_type = {
1290 	.name	= "wwan",
1291 };
1292 
1293 int
1294 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1295 {
1296 	struct usbnet			*dev;
1297 	struct net_device		*net;
1298 	struct usb_host_interface	*interface;
1299 	struct driver_info		*info;
1300 	struct usb_device		*xdev;
1301 	int				status;
1302 	const char			*name;
1303 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1304 
1305 	/* usbnet already took usb runtime pm, so have to enable the feature
1306 	 * for usb interface, otherwise usb_autopm_get_interface may return
1307 	 * failure if USB_SUSPEND(RUNTIME_PM) is enabled.
1308 	 */
1309 	if (!driver->supports_autosuspend) {
1310 		driver->supports_autosuspend = 1;
1311 		pm_runtime_enable(&udev->dev);
1312 	}
1313 
1314 	name = udev->dev.driver->name;
1315 	info = (struct driver_info *) prod->driver_info;
1316 	if (!info) {
1317 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1318 		return -ENODEV;
1319 	}
1320 	xdev = interface_to_usbdev (udev);
1321 	interface = udev->cur_altsetting;
1322 
1323 	usb_get_dev (xdev);
1324 
1325 	status = -ENOMEM;
1326 
1327 	// set up our own records
1328 	net = alloc_etherdev(sizeof(*dev));
1329 	if (!net) {
1330 		dbg ("can't kmalloc dev");
1331 		goto out;
1332 	}
1333 
1334 	/* netdev_printk() needs this so do it as early as possible */
1335 	SET_NETDEV_DEV(net, &udev->dev);
1336 
1337 	dev = netdev_priv(net);
1338 	dev->udev = xdev;
1339 	dev->intf = udev;
1340 	dev->driver_info = info;
1341 	dev->driver_name = name;
1342 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1343 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1344 	skb_queue_head_init (&dev->rxq);
1345 	skb_queue_head_init (&dev->txq);
1346 	skb_queue_head_init (&dev->done);
1347 	skb_queue_head_init(&dev->rxq_pause);
1348 	dev->bh.func = usbnet_bh;
1349 	dev->bh.data = (unsigned long) dev;
1350 	INIT_WORK (&dev->kevent, kevent);
1351 	init_usb_anchor(&dev->deferred);
1352 	dev->delay.function = usbnet_bh;
1353 	dev->delay.data = (unsigned long) dev;
1354 	init_timer (&dev->delay);
1355 	mutex_init (&dev->phy_mutex);
1356 
1357 	dev->net = net;
1358 	strcpy (net->name, "usb%d");
1359 	memcpy (net->dev_addr, node_id, sizeof node_id);
1360 
1361 	/* rx and tx sides can use different message sizes;
1362 	 * bind() should set rx_urb_size in that case.
1363 	 */
1364 	dev->hard_mtu = net->mtu + net->hard_header_len;
1365 #if 0
1366 // dma_supported() is deeply broken on almost all architectures
1367 	// possible with some EHCI controllers
1368 	if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1369 		net->features |= NETIF_F_HIGHDMA;
1370 #endif
1371 
1372 	net->netdev_ops = &usbnet_netdev_ops;
1373 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1374 	net->ethtool_ops = &usbnet_ethtool_ops;
1375 
1376 	// allow device-specific bind/init procedures
1377 	// NOTE net->name still not usable ...
1378 	if (info->bind) {
1379 		status = info->bind (dev, udev);
1380 		if (status < 0)
1381 			goto out1;
1382 
1383 		// heuristic:  "usb%d" for links we know are two-host,
1384 		// else "eth%d" when there's reasonable doubt.  userspace
1385 		// can rename the link if it knows better.
1386 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1387 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1388 		     (net->dev_addr [0] & 0x02) == 0))
1389 			strcpy (net->name, "eth%d");
1390 		/* WLAN devices should always be named "wlan%d" */
1391 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1392 			strcpy(net->name, "wlan%d");
1393 		/* WWAN devices should always be named "wwan%d" */
1394 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1395 			strcpy(net->name, "wwan%d");
1396 
1397 		/* maybe the remote can't receive an Ethernet MTU */
1398 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1399 			net->mtu = dev->hard_mtu - net->hard_header_len;
1400 	} else if (!info->in || !info->out)
1401 		status = usbnet_get_endpoints (dev, udev);
1402 	else {
1403 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1404 		dev->out = usb_sndbulkpipe (xdev, info->out);
1405 		if (!(info->flags & FLAG_NO_SETINT))
1406 			status = usb_set_interface (xdev,
1407 				interface->desc.bInterfaceNumber,
1408 				interface->desc.bAlternateSetting);
1409 		else
1410 			status = 0;
1411 
1412 	}
1413 	if (status >= 0 && dev->status)
1414 		status = init_status (dev, udev);
1415 	if (status < 0)
1416 		goto out3;
1417 
1418 	if (!dev->rx_urb_size)
1419 		dev->rx_urb_size = dev->hard_mtu;
1420 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1421 
1422 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1423 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1424 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1425 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1426 
1427 	status = register_netdev (net);
1428 	if (status)
1429 		goto out3;
1430 	netif_info(dev, probe, dev->net,
1431 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1432 		   udev->dev.driver->name,
1433 		   xdev->bus->bus_name, xdev->devpath,
1434 		   dev->driver_info->description,
1435 		   net->dev_addr);
1436 
1437 	// ok, it's ready to go.
1438 	usb_set_intfdata (udev, dev);
1439 
1440 	netif_device_attach (net);
1441 
1442 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1443 		netif_carrier_off(net);
1444 
1445 	return 0;
1446 
1447 out3:
1448 	if (info->unbind)
1449 		info->unbind (dev, udev);
1450 out1:
1451 	free_netdev(net);
1452 out:
1453 	usb_put_dev(xdev);
1454 	return status;
1455 }
1456 EXPORT_SYMBOL_GPL(usbnet_probe);
1457 
1458 /*-------------------------------------------------------------------------*/
1459 
1460 /*
1461  * suspend the whole driver as soon as the first interface is suspended
1462  * resume only when the last interface is resumed
1463  */
1464 
1465 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1466 {
1467 	struct usbnet		*dev = usb_get_intfdata(intf);
1468 
1469 	if (!dev->suspend_count++) {
1470 		spin_lock_irq(&dev->txq.lock);
1471 		/* don't autosuspend while transmitting */
1472 		if (dev->txq.qlen && (message.event & PM_EVENT_AUTO)) {
1473 			spin_unlock_irq(&dev->txq.lock);
1474 			return -EBUSY;
1475 		} else {
1476 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1477 			spin_unlock_irq(&dev->txq.lock);
1478 		}
1479 		/*
1480 		 * accelerate emptying of the rx and queues, to avoid
1481 		 * having everything error out.
1482 		 */
1483 		netif_device_detach (dev->net);
1484 		usbnet_terminate_urbs(dev);
1485 		usb_kill_urb(dev->interrupt);
1486 
1487 		/*
1488 		 * reattach so runtime management can use and
1489 		 * wake the device
1490 		 */
1491 		netif_device_attach (dev->net);
1492 	}
1493 	return 0;
1494 }
1495 EXPORT_SYMBOL_GPL(usbnet_suspend);
1496 
1497 int usbnet_resume (struct usb_interface *intf)
1498 {
1499 	struct usbnet		*dev = usb_get_intfdata(intf);
1500 	struct sk_buff          *skb;
1501 	struct urb              *res;
1502 	int                     retval;
1503 
1504 	if (!--dev->suspend_count) {
1505 		/* resume interrupt URBs */
1506 		if (dev->interrupt && test_bit(EVENT_DEV_OPEN, &dev->flags))
1507 			usb_submit_urb(dev->interrupt, GFP_NOIO);
1508 
1509 		spin_lock_irq(&dev->txq.lock);
1510 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1511 
1512 			skb = (struct sk_buff *)res->context;
1513 			retval = usb_submit_urb(res, GFP_ATOMIC);
1514 			if (retval < 0) {
1515 				dev_kfree_skb_any(skb);
1516 				usb_free_urb(res);
1517 				usb_autopm_put_interface_async(dev->intf);
1518 			} else {
1519 				dev->net->trans_start = jiffies;
1520 				__skb_queue_tail(&dev->txq, skb);
1521 			}
1522 		}
1523 
1524 		smp_mb();
1525 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1526 		spin_unlock_irq(&dev->txq.lock);
1527 		if (!(dev->txq.qlen >= TX_QLEN(dev)))
1528 			netif_start_queue(dev->net);
1529 		tasklet_schedule (&dev->bh);
1530 	}
1531 	return 0;
1532 }
1533 EXPORT_SYMBOL_GPL(usbnet_resume);
1534 
1535 
1536 /*-------------------------------------------------------------------------*/
1537 
1538 static int __init usbnet_init(void)
1539 {
1540 	/* compiler should optimize this out */
1541 	BUILD_BUG_ON (sizeof (((struct sk_buff *)0)->cb)
1542 			< sizeof (struct skb_data));
1543 
1544 	random_ether_addr(node_id);
1545 	return 0;
1546 }
1547 module_init(usbnet_init);
1548 
1549 static void __exit usbnet_exit(void)
1550 {
1551 }
1552 module_exit(usbnet_exit);
1553 
1554 MODULE_AUTHOR("David Brownell");
1555 MODULE_DESCRIPTION("USB network driver framework");
1556 MODULE_LICENSE("GPL");
1557