xref: /linux/drivers/net/usb/usbnet.c (revision d584e204ff574b43d4dcaa87ae233c4e9d08e1fb)
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->interrupt->transfer_flags |= URB_FREE_BUFFER;
214 			dev_dbg(&intf->dev,
215 				"status ep%din, %d bytes period %d\n",
216 				usb_pipeendpoint(pipe), maxp, period);
217 		}
218 	}
219 	return 0;
220 }
221 
222 /* Passes this packet up the stack, updating its accounting.
223  * Some link protocols batch packets, so their rx_fixup paths
224  * can return clones as well as just modify the original skb.
225  */
226 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
227 {
228 	int	status;
229 
230 	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
231 		skb_queue_tail(&dev->rxq_pause, skb);
232 		return;
233 	}
234 
235 	skb->protocol = eth_type_trans (skb, dev->net);
236 	dev->net->stats.rx_packets++;
237 	dev->net->stats.rx_bytes += skb->len;
238 
239 	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
240 		  skb->len + sizeof (struct ethhdr), skb->protocol);
241 	memset (skb->cb, 0, sizeof (struct skb_data));
242 
243 	if (skb_defer_rx_timestamp(skb))
244 		return;
245 
246 	status = netif_rx (skb);
247 	if (status != NET_RX_SUCCESS)
248 		netif_dbg(dev, rx_err, dev->net,
249 			  "netif_rx status %d\n", status);
250 }
251 EXPORT_SYMBOL_GPL(usbnet_skb_return);
252 
253 
254 /*-------------------------------------------------------------------------
255  *
256  * Network Device Driver (peer link to "Host Device", from USB host)
257  *
258  *-------------------------------------------------------------------------*/
259 
260 int usbnet_change_mtu (struct net_device *net, int new_mtu)
261 {
262 	struct usbnet	*dev = netdev_priv(net);
263 	int		ll_mtu = new_mtu + net->hard_header_len;
264 	int		old_hard_mtu = dev->hard_mtu;
265 	int		old_rx_urb_size = dev->rx_urb_size;
266 
267 	if (new_mtu <= 0)
268 		return -EINVAL;
269 	// no second zero-length packet read wanted after mtu-sized packets
270 	if ((ll_mtu % dev->maxpacket) == 0)
271 		return -EDOM;
272 	net->mtu = new_mtu;
273 
274 	dev->hard_mtu = net->mtu + net->hard_header_len;
275 	if (dev->rx_urb_size == old_hard_mtu) {
276 		dev->rx_urb_size = dev->hard_mtu;
277 		if (dev->rx_urb_size > old_rx_urb_size)
278 			usbnet_unlink_rx_urbs(dev);
279 	}
280 
281 	return 0;
282 }
283 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
284 
285 /*-------------------------------------------------------------------------*/
286 
287 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
288  * completion callbacks.  2.5 should have fixed those bugs...
289  */
290 
291 static void defer_bh(struct usbnet *dev, struct sk_buff *skb, struct sk_buff_head *list)
292 {
293 	unsigned long		flags;
294 
295 	spin_lock_irqsave(&list->lock, flags);
296 	__skb_unlink(skb, list);
297 	spin_unlock(&list->lock);
298 	spin_lock(&dev->done.lock);
299 	__skb_queue_tail(&dev->done, skb);
300 	if (dev->done.qlen == 1)
301 		tasklet_schedule(&dev->bh);
302 	spin_unlock_irqrestore(&dev->done.lock, flags);
303 }
304 
305 /* some work can't be done in tasklets, so we use keventd
306  *
307  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
308  * but tasklet_schedule() doesn't.  hope the failure is rare.
309  */
310 void usbnet_defer_kevent (struct usbnet *dev, int work)
311 {
312 	set_bit (work, &dev->flags);
313 	if (!schedule_work (&dev->kevent))
314 		netdev_err(dev->net, "kevent %d may have been dropped\n", work);
315 	else
316 		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
317 }
318 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
319 
320 /*-------------------------------------------------------------------------*/
321 
322 static void rx_complete (struct urb *urb);
323 
324 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
325 {
326 	struct sk_buff		*skb;
327 	struct skb_data		*entry;
328 	int			retval = 0;
329 	unsigned long		lockflags;
330 	size_t			size = dev->rx_urb_size;
331 
332 	skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
333 	if (!skb) {
334 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
335 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
336 		usb_free_urb (urb);
337 		return -ENOMEM;
338 	}
339 
340 	entry = (struct skb_data *) skb->cb;
341 	entry->urb = urb;
342 	entry->dev = dev;
343 	entry->state = rx_start;
344 	entry->length = 0;
345 
346 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
347 		skb->data, size, rx_complete, skb);
348 
349 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
350 
351 	if (netif_running (dev->net) &&
352 	    netif_device_present (dev->net) &&
353 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
354 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
355 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
356 		case -EPIPE:
357 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
358 			break;
359 		case -ENOMEM:
360 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
361 			break;
362 		case -ENODEV:
363 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
364 			netif_device_detach (dev->net);
365 			break;
366 		case -EHOSTUNREACH:
367 			retval = -ENOLINK;
368 			break;
369 		default:
370 			netif_dbg(dev, rx_err, dev->net,
371 				  "rx submit, %d\n", retval);
372 			tasklet_schedule (&dev->bh);
373 			break;
374 		case 0:
375 			__skb_queue_tail (&dev->rxq, skb);
376 		}
377 	} else {
378 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
379 		retval = -ENOLINK;
380 	}
381 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
382 	if (retval) {
383 		dev_kfree_skb_any (skb);
384 		usb_free_urb (urb);
385 	}
386 	return retval;
387 }
388 
389 
390 /*-------------------------------------------------------------------------*/
391 
392 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
393 {
394 	if (dev->driver_info->rx_fixup &&
395 	    !dev->driver_info->rx_fixup (dev, skb)) {
396 		/* With RX_ASSEMBLE, rx_fixup() must update counters */
397 		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
398 			dev->net->stats.rx_errors++;
399 		goto done;
400 	}
401 	// else network stack removes extra byte if we forced a short packet
402 
403 	if (skb->len) {
404 		/* all data was already cloned from skb inside the driver */
405 		if (dev->driver_info->flags & FLAG_MULTI_PACKET)
406 			dev_kfree_skb_any(skb);
407 		else
408 			usbnet_skb_return(dev, skb);
409 		return;
410 	}
411 
412 	netif_dbg(dev, rx_err, dev->net, "drop\n");
413 	dev->net->stats.rx_errors++;
414 done:
415 	skb_queue_tail(&dev->done, skb);
416 }
417 
418 /*-------------------------------------------------------------------------*/
419 
420 static void rx_complete (struct urb *urb)
421 {
422 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
423 	struct skb_data		*entry = (struct skb_data *) skb->cb;
424 	struct usbnet		*dev = entry->dev;
425 	int			urb_status = urb->status;
426 
427 	skb_put (skb, urb->actual_length);
428 	entry->state = rx_done;
429 	entry->urb = NULL;
430 
431 	switch (urb_status) {
432 	/* success */
433 	case 0:
434 		if (skb->len < dev->net->hard_header_len) {
435 			entry->state = rx_cleanup;
436 			dev->net->stats.rx_errors++;
437 			dev->net->stats.rx_length_errors++;
438 			netif_dbg(dev, rx_err, dev->net,
439 				  "rx length %d\n", skb->len);
440 		}
441 		break;
442 
443 	/* stalls need manual reset. this is rare ... except that
444 	 * when going through USB 2.0 TTs, unplug appears this way.
445 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
446 	 * storm, recovering as needed.
447 	 */
448 	case -EPIPE:
449 		dev->net->stats.rx_errors++;
450 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
451 		// FALLTHROUGH
452 
453 	/* software-driven interface shutdown */
454 	case -ECONNRESET:		/* async unlink */
455 	case -ESHUTDOWN:		/* hardware gone */
456 		netif_dbg(dev, ifdown, dev->net,
457 			  "rx shutdown, code %d\n", urb_status);
458 		goto block;
459 
460 	/* we get controller i/o faults during khubd disconnect() delays.
461 	 * throttle down resubmits, to avoid log floods; just temporarily,
462 	 * so we still recover when the fault isn't a khubd delay.
463 	 */
464 	case -EPROTO:
465 	case -ETIME:
466 	case -EILSEQ:
467 		dev->net->stats.rx_errors++;
468 		if (!timer_pending (&dev->delay)) {
469 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
470 			netif_dbg(dev, link, dev->net,
471 				  "rx throttle %d\n", urb_status);
472 		}
473 block:
474 		entry->state = rx_cleanup;
475 		entry->urb = urb;
476 		urb = NULL;
477 		break;
478 
479 	/* data overrun ... flush fifo? */
480 	case -EOVERFLOW:
481 		dev->net->stats.rx_over_errors++;
482 		// FALLTHROUGH
483 
484 	default:
485 		entry->state = rx_cleanup;
486 		dev->net->stats.rx_errors++;
487 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
488 		break;
489 	}
490 
491 	defer_bh(dev, skb, &dev->rxq);
492 
493 	if (urb) {
494 		if (netif_running (dev->net) &&
495 		    !test_bit (EVENT_RX_HALT, &dev->flags)) {
496 			rx_submit (dev, urb, GFP_ATOMIC);
497 			usb_mark_last_busy(dev->udev);
498 			return;
499 		}
500 		usb_free_urb (urb);
501 	}
502 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
503 }
504 
505 static void intr_complete (struct urb *urb)
506 {
507 	struct usbnet	*dev = urb->context;
508 	int		status = urb->status;
509 
510 	switch (status) {
511 	/* success */
512 	case 0:
513 		dev->driver_info->status(dev, urb);
514 		break;
515 
516 	/* software-driven interface shutdown */
517 	case -ENOENT:		/* urb killed */
518 	case -ESHUTDOWN:	/* hardware gone */
519 		netif_dbg(dev, ifdown, dev->net,
520 			  "intr shutdown, code %d\n", status);
521 		return;
522 
523 	/* NOTE:  not throttling like RX/TX, since this endpoint
524 	 * already polls infrequently
525 	 */
526 	default:
527 		netdev_dbg(dev->net, "intr status %d\n", status);
528 		break;
529 	}
530 
531 	if (!netif_running (dev->net))
532 		return;
533 
534 	memset(urb->transfer_buffer, 0, urb->transfer_buffer_length);
535 	status = usb_submit_urb (urb, GFP_ATOMIC);
536 	if (status != 0)
537 		netif_err(dev, timer, dev->net,
538 			  "intr resubmit --> %d\n", status);
539 }
540 
541 /*-------------------------------------------------------------------------*/
542 void usbnet_pause_rx(struct usbnet *dev)
543 {
544 	set_bit(EVENT_RX_PAUSED, &dev->flags);
545 
546 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
547 }
548 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
549 
550 void usbnet_resume_rx(struct usbnet *dev)
551 {
552 	struct sk_buff *skb;
553 	int num = 0;
554 
555 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
556 
557 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
558 		usbnet_skb_return(dev, skb);
559 		num++;
560 	}
561 
562 	tasklet_schedule(&dev->bh);
563 
564 	netif_dbg(dev, rx_status, dev->net,
565 		  "paused rx queue disabled, %d skbs requeued\n", num);
566 }
567 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
568 
569 void usbnet_purge_paused_rxq(struct usbnet *dev)
570 {
571 	skb_queue_purge(&dev->rxq_pause);
572 }
573 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
574 
575 /*-------------------------------------------------------------------------*/
576 
577 // unlink pending rx/tx; completion handlers do all other cleanup
578 
579 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
580 {
581 	unsigned long		flags;
582 	struct sk_buff		*skb, *skbnext;
583 	int			count = 0;
584 
585 	spin_lock_irqsave (&q->lock, flags);
586 	skb_queue_walk_safe(q, skb, skbnext) {
587 		struct skb_data		*entry;
588 		struct urb		*urb;
589 		int			retval;
590 
591 		entry = (struct skb_data *) skb->cb;
592 		urb = entry->urb;
593 
594 		/*
595 		 * Get reference count of the URB to avoid it to be
596 		 * freed during usb_unlink_urb, which may trigger
597 		 * use-after-free problem inside usb_unlink_urb since
598 		 * usb_unlink_urb is always racing with .complete
599 		 * handler(include defer_bh).
600 		 */
601 		usb_get_urb(urb);
602 		spin_unlock_irqrestore(&q->lock, flags);
603 		// during some PM-driven resume scenarios,
604 		// these (async) unlinks complete immediately
605 		retval = usb_unlink_urb (urb);
606 		if (retval != -EINPROGRESS && retval != 0)
607 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
608 		else
609 			count++;
610 		usb_put_urb(urb);
611 		spin_lock_irqsave(&q->lock, flags);
612 	}
613 	spin_unlock_irqrestore (&q->lock, flags);
614 	return count;
615 }
616 
617 // Flush all pending rx urbs
618 // minidrivers may need to do this when the MTU changes
619 
620 void usbnet_unlink_rx_urbs(struct usbnet *dev)
621 {
622 	if (netif_running(dev->net)) {
623 		(void) unlink_urbs (dev, &dev->rxq);
624 		tasklet_schedule(&dev->bh);
625 	}
626 }
627 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
628 
629 /*-------------------------------------------------------------------------*/
630 
631 // precondition: never called in_interrupt
632 static void usbnet_terminate_urbs(struct usbnet *dev)
633 {
634 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
635 	DECLARE_WAITQUEUE(wait, current);
636 	int temp;
637 
638 	/* ensure there are no more active urbs */
639 	add_wait_queue(&unlink_wakeup, &wait);
640 	set_current_state(TASK_UNINTERRUPTIBLE);
641 	dev->wait = &unlink_wakeup;
642 	temp = unlink_urbs(dev, &dev->txq) +
643 		unlink_urbs(dev, &dev->rxq);
644 
645 	/* maybe wait for deletions to finish. */
646 	while (!skb_queue_empty(&dev->rxq)
647 		&& !skb_queue_empty(&dev->txq)
648 		&& !skb_queue_empty(&dev->done)) {
649 			schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
650 			set_current_state(TASK_UNINTERRUPTIBLE);
651 			netif_dbg(dev, ifdown, dev->net,
652 				  "waited for %d urb completions\n", temp);
653 	}
654 	set_current_state(TASK_RUNNING);
655 	dev->wait = NULL;
656 	remove_wait_queue(&unlink_wakeup, &wait);
657 }
658 
659 int usbnet_stop (struct net_device *net)
660 {
661 	struct usbnet		*dev = netdev_priv(net);
662 	struct driver_info	*info = dev->driver_info;
663 	int			retval;
664 
665 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
666 	netif_stop_queue (net);
667 
668 	netif_info(dev, ifdown, dev->net,
669 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
670 		   net->stats.rx_packets, net->stats.tx_packets,
671 		   net->stats.rx_errors, net->stats.tx_errors);
672 
673 	/* allow minidriver to stop correctly (wireless devices to turn off
674 	 * radio etc) */
675 	if (info->stop) {
676 		retval = info->stop(dev);
677 		if (retval < 0)
678 			netif_info(dev, ifdown, dev->net,
679 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
680 				   retval,
681 				   dev->udev->bus->bus_name, dev->udev->devpath,
682 				   info->description);
683 	}
684 
685 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
686 		usbnet_terminate_urbs(dev);
687 
688 	usb_kill_urb(dev->interrupt);
689 
690 	usbnet_purge_paused_rxq(dev);
691 
692 	/* deferred work (task, timer, softirq) must also stop.
693 	 * can't flush_scheduled_work() until we drop rtnl (later),
694 	 * else workers could deadlock; so make workers a NOP.
695 	 */
696 	dev->flags = 0;
697 	del_timer_sync (&dev->delay);
698 	tasklet_kill (&dev->bh);
699 	if (info->manage_power)
700 		info->manage_power(dev, 0);
701 	else
702 		usb_autopm_put_interface(dev->intf);
703 
704 	return 0;
705 }
706 EXPORT_SYMBOL_GPL(usbnet_stop);
707 
708 /*-------------------------------------------------------------------------*/
709 
710 // posts reads, and enables write queuing
711 
712 // precondition: never called in_interrupt
713 
714 int usbnet_open (struct net_device *net)
715 {
716 	struct usbnet		*dev = netdev_priv(net);
717 	int			retval;
718 	struct driver_info	*info = dev->driver_info;
719 
720 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
721 		netif_info(dev, ifup, dev->net,
722 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
723 			   retval,
724 			   dev->udev->bus->bus_name,
725 			   dev->udev->devpath,
726 			   info->description);
727 		goto done_nopm;
728 	}
729 
730 	// put into "known safe" state
731 	if (info->reset && (retval = info->reset (dev)) < 0) {
732 		netif_info(dev, ifup, dev->net,
733 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
734 			   retval,
735 			   dev->udev->bus->bus_name,
736 			   dev->udev->devpath,
737 			   info->description);
738 		goto done;
739 	}
740 
741 	// insist peer be connected
742 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
743 		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
744 		goto done;
745 	}
746 
747 	/* start any status interrupt transfer */
748 	if (dev->interrupt) {
749 		retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
750 		if (retval < 0) {
751 			netif_err(dev, ifup, dev->net,
752 				  "intr submit %d\n", retval);
753 			goto done;
754 		}
755 	}
756 
757 	set_bit(EVENT_DEV_OPEN, &dev->flags);
758 	netif_start_queue (net);
759 	netif_info(dev, ifup, dev->net,
760 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
761 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
762 		   dev->net->mtu,
763 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
764 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
765 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
766 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
767 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
768 		   "simple");
769 
770 	// delay posting reads until we're fully open
771 	tasklet_schedule (&dev->bh);
772 	if (info->manage_power) {
773 		retval = info->manage_power(dev, 1);
774 		if (retval < 0)
775 			goto done;
776 		usb_autopm_put_interface(dev->intf);
777 	}
778 	return retval;
779 
780 done:
781 	usb_autopm_put_interface(dev->intf);
782 done_nopm:
783 	return retval;
784 }
785 EXPORT_SYMBOL_GPL(usbnet_open);
786 
787 /*-------------------------------------------------------------------------*/
788 
789 /* ethtool methods; minidrivers may need to add some more, but
790  * they'll probably want to use this base set.
791  */
792 
793 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
794 {
795 	struct usbnet *dev = netdev_priv(net);
796 
797 	if (!dev->mii.mdio_read)
798 		return -EOPNOTSUPP;
799 
800 	return mii_ethtool_gset(&dev->mii, cmd);
801 }
802 EXPORT_SYMBOL_GPL(usbnet_get_settings);
803 
804 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
805 {
806 	struct usbnet *dev = netdev_priv(net);
807 	int retval;
808 
809 	if (!dev->mii.mdio_write)
810 		return -EOPNOTSUPP;
811 
812 	retval = mii_ethtool_sset(&dev->mii, cmd);
813 
814 	/* link speed/duplex might have changed */
815 	if (dev->driver_info->link_reset)
816 		dev->driver_info->link_reset(dev);
817 
818 	return retval;
819 
820 }
821 EXPORT_SYMBOL_GPL(usbnet_set_settings);
822 
823 u32 usbnet_get_link (struct net_device *net)
824 {
825 	struct usbnet *dev = netdev_priv(net);
826 
827 	/* If a check_connect is defined, return its result */
828 	if (dev->driver_info->check_connect)
829 		return dev->driver_info->check_connect (dev) == 0;
830 
831 	/* if the device has mii operations, use those */
832 	if (dev->mii.mdio_read)
833 		return mii_link_ok(&dev->mii);
834 
835 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
836 	return ethtool_op_get_link(net);
837 }
838 EXPORT_SYMBOL_GPL(usbnet_get_link);
839 
840 int usbnet_nway_reset(struct net_device *net)
841 {
842 	struct usbnet *dev = netdev_priv(net);
843 
844 	if (!dev->mii.mdio_write)
845 		return -EOPNOTSUPP;
846 
847 	return mii_nway_restart(&dev->mii);
848 }
849 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
850 
851 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
852 {
853 	struct usbnet *dev = netdev_priv(net);
854 
855 	strncpy (info->driver, dev->driver_name, sizeof info->driver);
856 	strncpy (info->version, DRIVER_VERSION, sizeof info->version);
857 	strncpy (info->fw_version, dev->driver_info->description,
858 		sizeof info->fw_version);
859 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
860 }
861 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
862 
863 u32 usbnet_get_msglevel (struct net_device *net)
864 {
865 	struct usbnet *dev = netdev_priv(net);
866 
867 	return dev->msg_enable;
868 }
869 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
870 
871 void usbnet_set_msglevel (struct net_device *net, u32 level)
872 {
873 	struct usbnet *dev = netdev_priv(net);
874 
875 	dev->msg_enable = level;
876 }
877 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
878 
879 /* drivers may override default ethtool_ops in their bind() routine */
880 static const struct ethtool_ops usbnet_ethtool_ops = {
881 	.get_settings		= usbnet_get_settings,
882 	.set_settings		= usbnet_set_settings,
883 	.get_link		= usbnet_get_link,
884 	.nway_reset		= usbnet_nway_reset,
885 	.get_drvinfo		= usbnet_get_drvinfo,
886 	.get_msglevel		= usbnet_get_msglevel,
887 	.set_msglevel		= usbnet_set_msglevel,
888 };
889 
890 /*-------------------------------------------------------------------------*/
891 
892 /* work that cannot be done in interrupt context uses keventd.
893  *
894  * NOTE:  with 2.5 we could do more of this using completion callbacks,
895  * especially now that control transfers can be queued.
896  */
897 static void
898 kevent (struct work_struct *work)
899 {
900 	struct usbnet		*dev =
901 		container_of(work, struct usbnet, kevent);
902 	int			status;
903 
904 	/* usb_clear_halt() needs a thread context */
905 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
906 		unlink_urbs (dev, &dev->txq);
907 		status = usb_autopm_get_interface(dev->intf);
908 		if (status < 0)
909 			goto fail_pipe;
910 		status = usb_clear_halt (dev->udev, dev->out);
911 		usb_autopm_put_interface(dev->intf);
912 		if (status < 0 &&
913 		    status != -EPIPE &&
914 		    status != -ESHUTDOWN) {
915 			if (netif_msg_tx_err (dev))
916 fail_pipe:
917 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
918 					   status);
919 		} else {
920 			clear_bit (EVENT_TX_HALT, &dev->flags);
921 			if (status != -ESHUTDOWN)
922 				netif_wake_queue (dev->net);
923 		}
924 	}
925 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
926 		unlink_urbs (dev, &dev->rxq);
927 		status = usb_autopm_get_interface(dev->intf);
928 		if (status < 0)
929 			goto fail_halt;
930 		status = usb_clear_halt (dev->udev, dev->in);
931 		usb_autopm_put_interface(dev->intf);
932 		if (status < 0 &&
933 		    status != -EPIPE &&
934 		    status != -ESHUTDOWN) {
935 			if (netif_msg_rx_err (dev))
936 fail_halt:
937 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
938 					   status);
939 		} else {
940 			clear_bit (EVENT_RX_HALT, &dev->flags);
941 			tasklet_schedule (&dev->bh);
942 		}
943 	}
944 
945 	/* tasklet could resubmit itself forever if memory is tight */
946 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
947 		struct urb	*urb = NULL;
948 		int resched = 1;
949 
950 		if (netif_running (dev->net))
951 			urb = usb_alloc_urb (0, GFP_KERNEL);
952 		else
953 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
954 		if (urb != NULL) {
955 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
956 			status = usb_autopm_get_interface(dev->intf);
957 			if (status < 0) {
958 				usb_free_urb(urb);
959 				goto fail_lowmem;
960 			}
961 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
962 				resched = 0;
963 			usb_autopm_put_interface(dev->intf);
964 fail_lowmem:
965 			if (resched)
966 				tasklet_schedule (&dev->bh);
967 		}
968 	}
969 
970 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
971 		struct driver_info	*info = dev->driver_info;
972 		int			retval = 0;
973 
974 		clear_bit (EVENT_LINK_RESET, &dev->flags);
975 		status = usb_autopm_get_interface(dev->intf);
976 		if (status < 0)
977 			goto skip_reset;
978 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
979 			usb_autopm_put_interface(dev->intf);
980 skip_reset:
981 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
982 				    retval,
983 				    dev->udev->bus->bus_name,
984 				    dev->udev->devpath,
985 				    info->description);
986 		} else {
987 			usb_autopm_put_interface(dev->intf);
988 		}
989 	}
990 
991 	if (dev->flags)
992 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
993 }
994 
995 /*-------------------------------------------------------------------------*/
996 
997 static void tx_complete (struct urb *urb)
998 {
999 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1000 	struct skb_data		*entry = (struct skb_data *) skb->cb;
1001 	struct usbnet		*dev = entry->dev;
1002 
1003 	if (urb->status == 0) {
1004 		if (!(dev->driver_info->flags & FLAG_MULTI_PACKET))
1005 			dev->net->stats.tx_packets++;
1006 		dev->net->stats.tx_bytes += entry->length;
1007 	} else {
1008 		dev->net->stats.tx_errors++;
1009 
1010 		switch (urb->status) {
1011 		case -EPIPE:
1012 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1013 			break;
1014 
1015 		/* software-driven interface shutdown */
1016 		case -ECONNRESET:		// async unlink
1017 		case -ESHUTDOWN:		// hardware gone
1018 			break;
1019 
1020 		// like rx, tx gets controller i/o faults during khubd delays
1021 		// and so it uses the same throttling mechanism.
1022 		case -EPROTO:
1023 		case -ETIME:
1024 		case -EILSEQ:
1025 			usb_mark_last_busy(dev->udev);
1026 			if (!timer_pending (&dev->delay)) {
1027 				mod_timer (&dev->delay,
1028 					jiffies + THROTTLE_JIFFIES);
1029 				netif_dbg(dev, link, dev->net,
1030 					  "tx throttle %d\n", urb->status);
1031 			}
1032 			netif_stop_queue (dev->net);
1033 			break;
1034 		default:
1035 			netif_dbg(dev, tx_err, dev->net,
1036 				  "tx err %d\n", entry->urb->status);
1037 			break;
1038 		}
1039 	}
1040 
1041 	usb_autopm_put_interface_async(dev->intf);
1042 	entry->state = tx_done;
1043 	defer_bh(dev, skb, &dev->txq);
1044 }
1045 
1046 /*-------------------------------------------------------------------------*/
1047 
1048 void usbnet_tx_timeout (struct net_device *net)
1049 {
1050 	struct usbnet		*dev = netdev_priv(net);
1051 
1052 	unlink_urbs (dev, &dev->txq);
1053 	tasklet_schedule (&dev->bh);
1054 
1055 	// FIXME: device recovery -- reset?
1056 }
1057 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1058 
1059 /*-------------------------------------------------------------------------*/
1060 
1061 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1062 				     struct net_device *net)
1063 {
1064 	struct usbnet		*dev = netdev_priv(net);
1065 	int			length;
1066 	struct urb		*urb = NULL;
1067 	struct skb_data		*entry;
1068 	struct driver_info	*info = dev->driver_info;
1069 	unsigned long		flags;
1070 	int retval;
1071 
1072 	if (skb)
1073 		skb_tx_timestamp(skb);
1074 
1075 	// some devices want funky USB-level framing, for
1076 	// win32 driver (usually) and/or hardware quirks
1077 	if (info->tx_fixup) {
1078 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1079 		if (!skb) {
1080 			if (netif_msg_tx_err(dev)) {
1081 				netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1082 				goto drop;
1083 			} else {
1084 				/* cdc_ncm collected packet; waits for more */
1085 				goto not_drop;
1086 			}
1087 		}
1088 	}
1089 	length = skb->len;
1090 
1091 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1092 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1093 		goto drop;
1094 	}
1095 
1096 	entry = (struct skb_data *) skb->cb;
1097 	entry->urb = urb;
1098 	entry->dev = dev;
1099 	entry->state = tx_start;
1100 	entry->length = length;
1101 
1102 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1103 			skb->data, skb->len, tx_complete, skb);
1104 
1105 	/* don't assume the hardware handles USB_ZERO_PACKET
1106 	 * NOTE:  strictly conforming cdc-ether devices should expect
1107 	 * the ZLP here, but ignore the one-byte packet.
1108 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1109 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1110 	 * packet itself if needed.
1111 	 */
1112 	if (length % dev->maxpacket == 0) {
1113 		if (!(info->flags & FLAG_SEND_ZLP)) {
1114 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1115 				urb->transfer_buffer_length++;
1116 				if (skb_tailroom(skb)) {
1117 					skb->data[skb->len] = 0;
1118 					__skb_put(skb, 1);
1119 				}
1120 			}
1121 		} else
1122 			urb->transfer_flags |= URB_ZERO_PACKET;
1123 	}
1124 
1125 	spin_lock_irqsave(&dev->txq.lock, flags);
1126 	retval = usb_autopm_get_interface_async(dev->intf);
1127 	if (retval < 0) {
1128 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1129 		goto drop;
1130 	}
1131 
1132 #ifdef CONFIG_PM
1133 	/* if this triggers the device is still a sleep */
1134 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1135 		/* transmission will be done in resume */
1136 		usb_anchor_urb(urb, &dev->deferred);
1137 		/* no use to process more packets */
1138 		netif_stop_queue(net);
1139 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1140 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1141 		goto deferred;
1142 	}
1143 #endif
1144 
1145 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1146 	case -EPIPE:
1147 		netif_stop_queue (net);
1148 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1149 		usb_autopm_put_interface_async(dev->intf);
1150 		break;
1151 	default:
1152 		usb_autopm_put_interface_async(dev->intf);
1153 		netif_dbg(dev, tx_err, dev->net,
1154 			  "tx: submit urb err %d\n", retval);
1155 		break;
1156 	case 0:
1157 		net->trans_start = jiffies;
1158 		__skb_queue_tail (&dev->txq, skb);
1159 		if (dev->txq.qlen >= TX_QLEN (dev))
1160 			netif_stop_queue (net);
1161 	}
1162 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1163 
1164 	if (retval) {
1165 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1166 drop:
1167 		dev->net->stats.tx_dropped++;
1168 not_drop:
1169 		if (skb)
1170 			dev_kfree_skb_any (skb);
1171 		usb_free_urb (urb);
1172 	} else
1173 		netif_dbg(dev, tx_queued, dev->net,
1174 			  "> tx, len %d, type 0x%x\n", length, skb->protocol);
1175 #ifdef CONFIG_PM
1176 deferred:
1177 #endif
1178 	return NETDEV_TX_OK;
1179 }
1180 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1181 
1182 /*-------------------------------------------------------------------------*/
1183 
1184 // tasklet (work deferred from completions, in_irq) or timer
1185 
1186 static void usbnet_bh (unsigned long param)
1187 {
1188 	struct usbnet		*dev = (struct usbnet *) param;
1189 	struct sk_buff		*skb;
1190 	struct skb_data		*entry;
1191 
1192 	while ((skb = skb_dequeue (&dev->done))) {
1193 		entry = (struct skb_data *) skb->cb;
1194 		switch (entry->state) {
1195 		case rx_done:
1196 			entry->state = rx_cleanup;
1197 			rx_process (dev, skb);
1198 			continue;
1199 		case tx_done:
1200 		case rx_cleanup:
1201 			usb_free_urb (entry->urb);
1202 			dev_kfree_skb (skb);
1203 			continue;
1204 		default:
1205 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1206 		}
1207 	}
1208 
1209 	// waiting for all pending urbs to complete?
1210 	if (dev->wait) {
1211 		if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
1212 			wake_up (dev->wait);
1213 		}
1214 
1215 	// or are we maybe short a few urbs?
1216 	} else if (netif_running (dev->net) &&
1217 		   netif_device_present (dev->net) &&
1218 		   !timer_pending (&dev->delay) &&
1219 		   !test_bit (EVENT_RX_HALT, &dev->flags)) {
1220 		int	temp = dev->rxq.qlen;
1221 		int	qlen = RX_QLEN (dev);
1222 
1223 		if (temp < qlen) {
1224 			struct urb	*urb;
1225 			int		i;
1226 
1227 			// don't refill the queue all at once
1228 			for (i = 0; i < 10 && dev->rxq.qlen < qlen; i++) {
1229 				urb = usb_alloc_urb (0, GFP_ATOMIC);
1230 				if (urb != NULL) {
1231 					if (rx_submit (dev, urb, GFP_ATOMIC) ==
1232 					    -ENOLINK)
1233 						return;
1234 				}
1235 			}
1236 			if (temp != dev->rxq.qlen)
1237 				netif_dbg(dev, link, dev->net,
1238 					  "rxqlen %d --> %d\n",
1239 					  temp, dev->rxq.qlen);
1240 			if (dev->rxq.qlen < qlen)
1241 				tasklet_schedule (&dev->bh);
1242 		}
1243 		if (dev->txq.qlen < TX_QLEN (dev))
1244 			netif_wake_queue (dev->net);
1245 	}
1246 }
1247 
1248 
1249 /*-------------------------------------------------------------------------
1250  *
1251  * USB Device Driver support
1252  *
1253  *-------------------------------------------------------------------------*/
1254 
1255 // precondition: never called in_interrupt
1256 
1257 void usbnet_disconnect (struct usb_interface *intf)
1258 {
1259 	struct usbnet		*dev;
1260 	struct usb_device	*xdev;
1261 	struct net_device	*net;
1262 
1263 	dev = usb_get_intfdata(intf);
1264 	usb_set_intfdata(intf, NULL);
1265 	if (!dev)
1266 		return;
1267 
1268 	xdev = interface_to_usbdev (intf);
1269 
1270 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1271 		   intf->dev.driver->name,
1272 		   xdev->bus->bus_name, xdev->devpath,
1273 		   dev->driver_info->description);
1274 
1275 	net = dev->net;
1276 	unregister_netdev (net);
1277 
1278 	cancel_work_sync(&dev->kevent);
1279 
1280 	if (dev->driver_info->unbind)
1281 		dev->driver_info->unbind (dev, intf);
1282 
1283 	usb_kill_urb(dev->interrupt);
1284 	usb_free_urb(dev->interrupt);
1285 
1286 	free_netdev(net);
1287 	usb_put_dev (xdev);
1288 }
1289 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1290 
1291 static const struct net_device_ops usbnet_netdev_ops = {
1292 	.ndo_open		= usbnet_open,
1293 	.ndo_stop		= usbnet_stop,
1294 	.ndo_start_xmit		= usbnet_start_xmit,
1295 	.ndo_tx_timeout		= usbnet_tx_timeout,
1296 	.ndo_change_mtu		= usbnet_change_mtu,
1297 	.ndo_set_mac_address 	= eth_mac_addr,
1298 	.ndo_validate_addr	= eth_validate_addr,
1299 };
1300 
1301 /*-------------------------------------------------------------------------*/
1302 
1303 // precondition: never called in_interrupt
1304 
1305 static struct device_type wlan_type = {
1306 	.name	= "wlan",
1307 };
1308 
1309 static struct device_type wwan_type = {
1310 	.name	= "wwan",
1311 };
1312 
1313 int
1314 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1315 {
1316 	struct usbnet			*dev;
1317 	struct net_device		*net;
1318 	struct usb_host_interface	*interface;
1319 	struct driver_info		*info;
1320 	struct usb_device		*xdev;
1321 	int				status;
1322 	const char			*name;
1323 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1324 
1325 	/* usbnet already took usb runtime pm, so have to enable the feature
1326 	 * for usb interface, otherwise usb_autopm_get_interface may return
1327 	 * failure if USB_SUSPEND(RUNTIME_PM) is enabled.
1328 	 */
1329 	if (!driver->supports_autosuspend) {
1330 		driver->supports_autosuspend = 1;
1331 		pm_runtime_enable(&udev->dev);
1332 	}
1333 
1334 	name = udev->dev.driver->name;
1335 	info = (struct driver_info *) prod->driver_info;
1336 	if (!info) {
1337 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1338 		return -ENODEV;
1339 	}
1340 	xdev = interface_to_usbdev (udev);
1341 	interface = udev->cur_altsetting;
1342 
1343 	usb_get_dev (xdev);
1344 
1345 	status = -ENOMEM;
1346 
1347 	// set up our own records
1348 	net = alloc_etherdev(sizeof(*dev));
1349 	if (!net)
1350 		goto out;
1351 
1352 	/* netdev_printk() needs this so do it as early as possible */
1353 	SET_NETDEV_DEV(net, &udev->dev);
1354 
1355 	dev = netdev_priv(net);
1356 	dev->udev = xdev;
1357 	dev->intf = udev;
1358 	dev->driver_info = info;
1359 	dev->driver_name = name;
1360 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1361 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1362 	skb_queue_head_init (&dev->rxq);
1363 	skb_queue_head_init (&dev->txq);
1364 	skb_queue_head_init (&dev->done);
1365 	skb_queue_head_init(&dev->rxq_pause);
1366 	dev->bh.func = usbnet_bh;
1367 	dev->bh.data = (unsigned long) dev;
1368 	INIT_WORK (&dev->kevent, kevent);
1369 	init_usb_anchor(&dev->deferred);
1370 	dev->delay.function = usbnet_bh;
1371 	dev->delay.data = (unsigned long) dev;
1372 	init_timer (&dev->delay);
1373 	mutex_init (&dev->phy_mutex);
1374 
1375 	dev->net = net;
1376 	strcpy (net->name, "usb%d");
1377 	memcpy (net->dev_addr, node_id, sizeof node_id);
1378 
1379 	/* rx and tx sides can use different message sizes;
1380 	 * bind() should set rx_urb_size in that case.
1381 	 */
1382 	dev->hard_mtu = net->mtu + net->hard_header_len;
1383 #if 0
1384 // dma_supported() is deeply broken on almost all architectures
1385 	// possible with some EHCI controllers
1386 	if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1387 		net->features |= NETIF_F_HIGHDMA;
1388 #endif
1389 
1390 	net->netdev_ops = &usbnet_netdev_ops;
1391 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1392 	net->ethtool_ops = &usbnet_ethtool_ops;
1393 
1394 	// allow device-specific bind/init procedures
1395 	// NOTE net->name still not usable ...
1396 	if (info->bind) {
1397 		status = info->bind (dev, udev);
1398 		if (status < 0)
1399 			goto out1;
1400 
1401 		// heuristic:  "usb%d" for links we know are two-host,
1402 		// else "eth%d" when there's reasonable doubt.  userspace
1403 		// can rename the link if it knows better.
1404 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1405 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1406 		     (net->dev_addr [0] & 0x02) == 0))
1407 			strcpy (net->name, "eth%d");
1408 		/* WLAN devices should always be named "wlan%d" */
1409 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1410 			strcpy(net->name, "wlan%d");
1411 		/* WWAN devices should always be named "wwan%d" */
1412 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1413 			strcpy(net->name, "wwan%d");
1414 
1415 		/* maybe the remote can't receive an Ethernet MTU */
1416 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1417 			net->mtu = dev->hard_mtu - net->hard_header_len;
1418 	} else if (!info->in || !info->out)
1419 		status = usbnet_get_endpoints (dev, udev);
1420 	else {
1421 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1422 		dev->out = usb_sndbulkpipe (xdev, info->out);
1423 		if (!(info->flags & FLAG_NO_SETINT))
1424 			status = usb_set_interface (xdev,
1425 				interface->desc.bInterfaceNumber,
1426 				interface->desc.bAlternateSetting);
1427 		else
1428 			status = 0;
1429 
1430 	}
1431 	if (status >= 0 && dev->status)
1432 		status = init_status (dev, udev);
1433 	if (status < 0)
1434 		goto out3;
1435 
1436 	if (!dev->rx_urb_size)
1437 		dev->rx_urb_size = dev->hard_mtu;
1438 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1439 
1440 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1441 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1442 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1443 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1444 
1445 	status = register_netdev (net);
1446 	if (status)
1447 		goto out4;
1448 	netif_info(dev, probe, dev->net,
1449 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1450 		   udev->dev.driver->name,
1451 		   xdev->bus->bus_name, xdev->devpath,
1452 		   dev->driver_info->description,
1453 		   net->dev_addr);
1454 
1455 	// ok, it's ready to go.
1456 	usb_set_intfdata (udev, dev);
1457 
1458 	netif_device_attach (net);
1459 
1460 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1461 		netif_carrier_off(net);
1462 
1463 	return 0;
1464 
1465 out4:
1466 	usb_free_urb(dev->interrupt);
1467 out3:
1468 	if (info->unbind)
1469 		info->unbind (dev, udev);
1470 out1:
1471 	free_netdev(net);
1472 out:
1473 	usb_put_dev(xdev);
1474 	return status;
1475 }
1476 EXPORT_SYMBOL_GPL(usbnet_probe);
1477 
1478 /*-------------------------------------------------------------------------*/
1479 
1480 /*
1481  * suspend the whole driver as soon as the first interface is suspended
1482  * resume only when the last interface is resumed
1483  */
1484 
1485 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1486 {
1487 	struct usbnet		*dev = usb_get_intfdata(intf);
1488 
1489 	if (!dev->suspend_count++) {
1490 		spin_lock_irq(&dev->txq.lock);
1491 		/* don't autosuspend while transmitting */
1492 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1493 			spin_unlock_irq(&dev->txq.lock);
1494 			return -EBUSY;
1495 		} else {
1496 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1497 			spin_unlock_irq(&dev->txq.lock);
1498 		}
1499 		/*
1500 		 * accelerate emptying of the rx and queues, to avoid
1501 		 * having everything error out.
1502 		 */
1503 		netif_device_detach (dev->net);
1504 		usbnet_terminate_urbs(dev);
1505 		usb_kill_urb(dev->interrupt);
1506 
1507 		/*
1508 		 * reattach so runtime management can use and
1509 		 * wake the device
1510 		 */
1511 		netif_device_attach (dev->net);
1512 	}
1513 	return 0;
1514 }
1515 EXPORT_SYMBOL_GPL(usbnet_suspend);
1516 
1517 int usbnet_resume (struct usb_interface *intf)
1518 {
1519 	struct usbnet		*dev = usb_get_intfdata(intf);
1520 	struct sk_buff          *skb;
1521 	struct urb              *res;
1522 	int                     retval;
1523 
1524 	if (!--dev->suspend_count) {
1525 		/* resume interrupt URBs */
1526 		if (dev->interrupt && test_bit(EVENT_DEV_OPEN, &dev->flags))
1527 			usb_submit_urb(dev->interrupt, GFP_NOIO);
1528 
1529 		spin_lock_irq(&dev->txq.lock);
1530 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1531 
1532 			skb = (struct sk_buff *)res->context;
1533 			retval = usb_submit_urb(res, GFP_ATOMIC);
1534 			if (retval < 0) {
1535 				dev_kfree_skb_any(skb);
1536 				usb_free_urb(res);
1537 				usb_autopm_put_interface_async(dev->intf);
1538 			} else {
1539 				dev->net->trans_start = jiffies;
1540 				__skb_queue_tail(&dev->txq, skb);
1541 			}
1542 		}
1543 
1544 		smp_mb();
1545 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1546 		spin_unlock_irq(&dev->txq.lock);
1547 
1548 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1549 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1550 				netif_tx_wake_all_queues(dev->net);
1551 			tasklet_schedule (&dev->bh);
1552 		}
1553 	}
1554 	return 0;
1555 }
1556 EXPORT_SYMBOL_GPL(usbnet_resume);
1557 
1558 
1559 /*-------------------------------------------------------------------------*/
1560 
1561 static int __init usbnet_init(void)
1562 {
1563 	/* Compiler should optimize this out. */
1564 	BUILD_BUG_ON(
1565 		FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
1566 
1567 	random_ether_addr(node_id);
1568 	return 0;
1569 }
1570 module_init(usbnet_init);
1571 
1572 static void __exit usbnet_exit(void)
1573 {
1574 }
1575 module_exit(usbnet_exit);
1576 
1577 MODULE_AUTHOR("David Brownell");
1578 MODULE_DESCRIPTION("USB network driver framework");
1579 MODULE_LICENSE("GPL");
1580