xref: /openbmc/linux/drivers/net/usb/usbnet.c (revision 95e9fd10)
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 	struct usbnet	*dev = urb->context;
186 	int		status = urb->status;
187 
188 	switch (status) {
189 	/* success */
190 	case 0:
191 		dev->driver_info->status(dev, urb);
192 		break;
193 
194 	/* software-driven interface shutdown */
195 	case -ENOENT:		/* urb killed */
196 	case -ESHUTDOWN:	/* hardware gone */
197 		netif_dbg(dev, ifdown, dev->net,
198 			  "intr shutdown, code %d\n", status);
199 		return;
200 
201 	/* NOTE:  not throttling like RX/TX, since this endpoint
202 	 * already polls infrequently
203 	 */
204 	default:
205 		netdev_dbg(dev->net, "intr status %d\n", status);
206 		break;
207 	}
208 
209 	if (!netif_running (dev->net))
210 		return;
211 
212 	status = usb_submit_urb (urb, GFP_ATOMIC);
213 	if (status != 0)
214 		netif_err(dev, timer, dev->net,
215 			  "intr resubmit --> %d\n", status);
216 }
217 
218 static int init_status (struct usbnet *dev, struct usb_interface *intf)
219 {
220 	char		*buf = NULL;
221 	unsigned	pipe = 0;
222 	unsigned	maxp;
223 	unsigned	period;
224 
225 	if (!dev->driver_info->status)
226 		return 0;
227 
228 	pipe = usb_rcvintpipe (dev->udev,
229 			dev->status->desc.bEndpointAddress
230 				& USB_ENDPOINT_NUMBER_MASK);
231 	maxp = usb_maxpacket (dev->udev, pipe, 0);
232 
233 	/* avoid 1 msec chatter:  min 8 msec poll rate */
234 	period = max ((int) dev->status->desc.bInterval,
235 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
236 
237 	buf = kmalloc (maxp, GFP_KERNEL);
238 	if (buf) {
239 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
240 		if (!dev->interrupt) {
241 			kfree (buf);
242 			return -ENOMEM;
243 		} else {
244 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
245 				buf, maxp, intr_complete, dev, period);
246 			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
247 			dev_dbg(&intf->dev,
248 				"status ep%din, %d bytes period %d\n",
249 				usb_pipeendpoint(pipe), maxp, period);
250 		}
251 	}
252 	return 0;
253 }
254 
255 /* Passes this packet up the stack, updating its accounting.
256  * Some link protocols batch packets, so their rx_fixup paths
257  * can return clones as well as just modify the original skb.
258  */
259 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
260 {
261 	int	status;
262 
263 	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
264 		skb_queue_tail(&dev->rxq_pause, skb);
265 		return;
266 	}
267 
268 	skb->protocol = eth_type_trans (skb, dev->net);
269 	dev->net->stats.rx_packets++;
270 	dev->net->stats.rx_bytes += skb->len;
271 
272 	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
273 		  skb->len + sizeof (struct ethhdr), skb->protocol);
274 	memset (skb->cb, 0, sizeof (struct skb_data));
275 
276 	if (skb_defer_rx_timestamp(skb))
277 		return;
278 
279 	status = netif_rx (skb);
280 	if (status != NET_RX_SUCCESS)
281 		netif_dbg(dev, rx_err, dev->net,
282 			  "netif_rx status %d\n", status);
283 }
284 EXPORT_SYMBOL_GPL(usbnet_skb_return);
285 
286 
287 /*-------------------------------------------------------------------------
288  *
289  * Network Device Driver (peer link to "Host Device", from USB host)
290  *
291  *-------------------------------------------------------------------------*/
292 
293 int usbnet_change_mtu (struct net_device *net, int new_mtu)
294 {
295 	struct usbnet	*dev = netdev_priv(net);
296 	int		ll_mtu = new_mtu + net->hard_header_len;
297 	int		old_hard_mtu = dev->hard_mtu;
298 	int		old_rx_urb_size = dev->rx_urb_size;
299 
300 	if (new_mtu <= 0)
301 		return -EINVAL;
302 	// no second zero-length packet read wanted after mtu-sized packets
303 	if ((ll_mtu % dev->maxpacket) == 0)
304 		return -EDOM;
305 	net->mtu = new_mtu;
306 
307 	dev->hard_mtu = net->mtu + net->hard_header_len;
308 	if (dev->rx_urb_size == old_hard_mtu) {
309 		dev->rx_urb_size = dev->hard_mtu;
310 		if (dev->rx_urb_size > old_rx_urb_size)
311 			usbnet_unlink_rx_urbs(dev);
312 	}
313 
314 	return 0;
315 }
316 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
317 
318 /* The caller must hold list->lock */
319 static void __usbnet_queue_skb(struct sk_buff_head *list,
320 			struct sk_buff *newsk, enum skb_state state)
321 {
322 	struct skb_data *entry = (struct skb_data *) newsk->cb;
323 
324 	__skb_queue_tail(list, newsk);
325 	entry->state = state;
326 }
327 
328 /*-------------------------------------------------------------------------*/
329 
330 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
331  * completion callbacks.  2.5 should have fixed those bugs...
332  */
333 
334 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
335 		struct sk_buff_head *list, enum skb_state state)
336 {
337 	unsigned long		flags;
338 	enum skb_state 		old_state;
339 	struct skb_data *entry = (struct skb_data *) skb->cb;
340 
341 	spin_lock_irqsave(&list->lock, flags);
342 	old_state = entry->state;
343 	entry->state = state;
344 	__skb_unlink(skb, list);
345 	spin_unlock(&list->lock);
346 	spin_lock(&dev->done.lock);
347 	__skb_queue_tail(&dev->done, skb);
348 	if (dev->done.qlen == 1)
349 		tasklet_schedule(&dev->bh);
350 	spin_unlock_irqrestore(&dev->done.lock, flags);
351 	return old_state;
352 }
353 
354 /* some work can't be done in tasklets, so we use keventd
355  *
356  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
357  * but tasklet_schedule() doesn't.  hope the failure is rare.
358  */
359 void usbnet_defer_kevent (struct usbnet *dev, int work)
360 {
361 	set_bit (work, &dev->flags);
362 	if (!schedule_work (&dev->kevent))
363 		netdev_err(dev->net, "kevent %d may have been dropped\n", work);
364 	else
365 		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
366 }
367 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
368 
369 /*-------------------------------------------------------------------------*/
370 
371 static void rx_complete (struct urb *urb);
372 
373 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
374 {
375 	struct sk_buff		*skb;
376 	struct skb_data		*entry;
377 	int			retval = 0;
378 	unsigned long		lockflags;
379 	size_t			size = dev->rx_urb_size;
380 
381 	skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
382 	if (!skb) {
383 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
384 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
385 		usb_free_urb (urb);
386 		return -ENOMEM;
387 	}
388 
389 	entry = (struct skb_data *) skb->cb;
390 	entry->urb = urb;
391 	entry->dev = dev;
392 	entry->length = 0;
393 
394 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
395 		skb->data, size, rx_complete, skb);
396 
397 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
398 
399 	if (netif_running (dev->net) &&
400 	    netif_device_present (dev->net) &&
401 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
402 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
403 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
404 		case -EPIPE:
405 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
406 			break;
407 		case -ENOMEM:
408 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
409 			break;
410 		case -ENODEV:
411 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
412 			netif_device_detach (dev->net);
413 			break;
414 		case -EHOSTUNREACH:
415 			retval = -ENOLINK;
416 			break;
417 		default:
418 			netif_dbg(dev, rx_err, dev->net,
419 				  "rx submit, %d\n", retval);
420 			tasklet_schedule (&dev->bh);
421 			break;
422 		case 0:
423 			__usbnet_queue_skb(&dev->rxq, skb, rx_start);
424 		}
425 	} else {
426 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
427 		retval = -ENOLINK;
428 	}
429 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
430 	if (retval) {
431 		dev_kfree_skb_any (skb);
432 		usb_free_urb (urb);
433 	}
434 	return retval;
435 }
436 
437 
438 /*-------------------------------------------------------------------------*/
439 
440 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
441 {
442 	if (dev->driver_info->rx_fixup &&
443 	    !dev->driver_info->rx_fixup (dev, skb)) {
444 		/* With RX_ASSEMBLE, rx_fixup() must update counters */
445 		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
446 			dev->net->stats.rx_errors++;
447 		goto done;
448 	}
449 	// else network stack removes extra byte if we forced a short packet
450 
451 	if (skb->len) {
452 		/* all data was already cloned from skb inside the driver */
453 		if (dev->driver_info->flags & FLAG_MULTI_PACKET)
454 			dev_kfree_skb_any(skb);
455 		else
456 			usbnet_skb_return(dev, skb);
457 		return;
458 	}
459 
460 	netif_dbg(dev, rx_err, dev->net, "drop\n");
461 	dev->net->stats.rx_errors++;
462 done:
463 	skb_queue_tail(&dev->done, skb);
464 }
465 
466 /*-------------------------------------------------------------------------*/
467 
468 static void rx_complete (struct urb *urb)
469 {
470 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
471 	struct skb_data		*entry = (struct skb_data *) skb->cb;
472 	struct usbnet		*dev = entry->dev;
473 	int			urb_status = urb->status;
474 	enum skb_state		state;
475 
476 	skb_put (skb, urb->actual_length);
477 	state = rx_done;
478 	entry->urb = NULL;
479 
480 	switch (urb_status) {
481 	/* success */
482 	case 0:
483 		if (skb->len < dev->net->hard_header_len) {
484 			state = rx_cleanup;
485 			dev->net->stats.rx_errors++;
486 			dev->net->stats.rx_length_errors++;
487 			netif_dbg(dev, rx_err, dev->net,
488 				  "rx length %d\n", skb->len);
489 		}
490 		break;
491 
492 	/* stalls need manual reset. this is rare ... except that
493 	 * when going through USB 2.0 TTs, unplug appears this way.
494 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
495 	 * storm, recovering as needed.
496 	 */
497 	case -EPIPE:
498 		dev->net->stats.rx_errors++;
499 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
500 		// FALLTHROUGH
501 
502 	/* software-driven interface shutdown */
503 	case -ECONNRESET:		/* async unlink */
504 	case -ESHUTDOWN:		/* hardware gone */
505 		netif_dbg(dev, ifdown, dev->net,
506 			  "rx shutdown, code %d\n", urb_status);
507 		goto block;
508 
509 	/* we get controller i/o faults during khubd disconnect() delays.
510 	 * throttle down resubmits, to avoid log floods; just temporarily,
511 	 * so we still recover when the fault isn't a khubd delay.
512 	 */
513 	case -EPROTO:
514 	case -ETIME:
515 	case -EILSEQ:
516 		dev->net->stats.rx_errors++;
517 		if (!timer_pending (&dev->delay)) {
518 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
519 			netif_dbg(dev, link, dev->net,
520 				  "rx throttle %d\n", urb_status);
521 		}
522 block:
523 		state = rx_cleanup;
524 		entry->urb = urb;
525 		urb = NULL;
526 		break;
527 
528 	/* data overrun ... flush fifo? */
529 	case -EOVERFLOW:
530 		dev->net->stats.rx_over_errors++;
531 		// FALLTHROUGH
532 
533 	default:
534 		state = rx_cleanup;
535 		dev->net->stats.rx_errors++;
536 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
537 		break;
538 	}
539 
540 	state = defer_bh(dev, skb, &dev->rxq, state);
541 
542 	if (urb) {
543 		if (netif_running (dev->net) &&
544 		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
545 		    state != unlink_start) {
546 			rx_submit (dev, urb, GFP_ATOMIC);
547 			usb_mark_last_busy(dev->udev);
548 			return;
549 		}
550 		usb_free_urb (urb);
551 	}
552 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
553 }
554 
555 /*-------------------------------------------------------------------------*/
556 void usbnet_pause_rx(struct usbnet *dev)
557 {
558 	set_bit(EVENT_RX_PAUSED, &dev->flags);
559 
560 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
561 }
562 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
563 
564 void usbnet_resume_rx(struct usbnet *dev)
565 {
566 	struct sk_buff *skb;
567 	int num = 0;
568 
569 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
570 
571 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
572 		usbnet_skb_return(dev, skb);
573 		num++;
574 	}
575 
576 	tasklet_schedule(&dev->bh);
577 
578 	netif_dbg(dev, rx_status, dev->net,
579 		  "paused rx queue disabled, %d skbs requeued\n", num);
580 }
581 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
582 
583 void usbnet_purge_paused_rxq(struct usbnet *dev)
584 {
585 	skb_queue_purge(&dev->rxq_pause);
586 }
587 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
588 
589 /*-------------------------------------------------------------------------*/
590 
591 // unlink pending rx/tx; completion handlers do all other cleanup
592 
593 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
594 {
595 	unsigned long		flags;
596 	struct sk_buff		*skb;
597 	int			count = 0;
598 
599 	spin_lock_irqsave (&q->lock, flags);
600 	while (!skb_queue_empty(q)) {
601 		struct skb_data		*entry;
602 		struct urb		*urb;
603 		int			retval;
604 
605 		skb_queue_walk(q, skb) {
606 			entry = (struct skb_data *) skb->cb;
607 			if (entry->state != unlink_start)
608 				goto found;
609 		}
610 		break;
611 found:
612 		entry->state = unlink_start;
613 		urb = entry->urb;
614 
615 		/*
616 		 * Get reference count of the URB to avoid it to be
617 		 * freed during usb_unlink_urb, which may trigger
618 		 * use-after-free problem inside usb_unlink_urb since
619 		 * usb_unlink_urb is always racing with .complete
620 		 * handler(include defer_bh).
621 		 */
622 		usb_get_urb(urb);
623 		spin_unlock_irqrestore(&q->lock, flags);
624 		// during some PM-driven resume scenarios,
625 		// these (async) unlinks complete immediately
626 		retval = usb_unlink_urb (urb);
627 		if (retval != -EINPROGRESS && retval != 0)
628 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
629 		else
630 			count++;
631 		usb_put_urb(urb);
632 		spin_lock_irqsave(&q->lock, flags);
633 	}
634 	spin_unlock_irqrestore (&q->lock, flags);
635 	return count;
636 }
637 
638 // Flush all pending rx urbs
639 // minidrivers may need to do this when the MTU changes
640 
641 void usbnet_unlink_rx_urbs(struct usbnet *dev)
642 {
643 	if (netif_running(dev->net)) {
644 		(void) unlink_urbs (dev, &dev->rxq);
645 		tasklet_schedule(&dev->bh);
646 	}
647 }
648 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
649 
650 /*-------------------------------------------------------------------------*/
651 
652 // precondition: never called in_interrupt
653 static void usbnet_terminate_urbs(struct usbnet *dev)
654 {
655 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
656 	DECLARE_WAITQUEUE(wait, current);
657 	int temp;
658 
659 	/* ensure there are no more active urbs */
660 	add_wait_queue(&unlink_wakeup, &wait);
661 	set_current_state(TASK_UNINTERRUPTIBLE);
662 	dev->wait = &unlink_wakeup;
663 	temp = unlink_urbs(dev, &dev->txq) +
664 		unlink_urbs(dev, &dev->rxq);
665 
666 	/* maybe wait for deletions to finish. */
667 	while (!skb_queue_empty(&dev->rxq)
668 		&& !skb_queue_empty(&dev->txq)
669 		&& !skb_queue_empty(&dev->done)) {
670 			schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
671 			set_current_state(TASK_UNINTERRUPTIBLE);
672 			netif_dbg(dev, ifdown, dev->net,
673 				  "waited for %d urb completions\n", temp);
674 	}
675 	set_current_state(TASK_RUNNING);
676 	dev->wait = NULL;
677 	remove_wait_queue(&unlink_wakeup, &wait);
678 }
679 
680 int usbnet_stop (struct net_device *net)
681 {
682 	struct usbnet		*dev = netdev_priv(net);
683 	struct driver_info	*info = dev->driver_info;
684 	int			retval;
685 
686 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
687 	netif_stop_queue (net);
688 
689 	netif_info(dev, ifdown, dev->net,
690 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
691 		   net->stats.rx_packets, net->stats.tx_packets,
692 		   net->stats.rx_errors, net->stats.tx_errors);
693 
694 	/* allow minidriver to stop correctly (wireless devices to turn off
695 	 * radio etc) */
696 	if (info->stop) {
697 		retval = info->stop(dev);
698 		if (retval < 0)
699 			netif_info(dev, ifdown, dev->net,
700 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
701 				   retval,
702 				   dev->udev->bus->bus_name, dev->udev->devpath,
703 				   info->description);
704 	}
705 
706 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
707 		usbnet_terminate_urbs(dev);
708 
709 	usb_kill_urb(dev->interrupt);
710 
711 	usbnet_purge_paused_rxq(dev);
712 
713 	/* deferred work (task, timer, softirq) must also stop.
714 	 * can't flush_scheduled_work() until we drop rtnl (later),
715 	 * else workers could deadlock; so make workers a NOP.
716 	 */
717 	dev->flags = 0;
718 	del_timer_sync (&dev->delay);
719 	tasklet_kill (&dev->bh);
720 	if (info->manage_power)
721 		info->manage_power(dev, 0);
722 	else
723 		usb_autopm_put_interface(dev->intf);
724 
725 	return 0;
726 }
727 EXPORT_SYMBOL_GPL(usbnet_stop);
728 
729 /*-------------------------------------------------------------------------*/
730 
731 // posts reads, and enables write queuing
732 
733 // precondition: never called in_interrupt
734 
735 int usbnet_open (struct net_device *net)
736 {
737 	struct usbnet		*dev = netdev_priv(net);
738 	int			retval;
739 	struct driver_info	*info = dev->driver_info;
740 
741 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
742 		netif_info(dev, ifup, dev->net,
743 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
744 			   retval,
745 			   dev->udev->bus->bus_name,
746 			   dev->udev->devpath,
747 			   info->description);
748 		goto done_nopm;
749 	}
750 
751 	// put into "known safe" state
752 	if (info->reset && (retval = info->reset (dev)) < 0) {
753 		netif_info(dev, ifup, dev->net,
754 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
755 			   retval,
756 			   dev->udev->bus->bus_name,
757 			   dev->udev->devpath,
758 			   info->description);
759 		goto done;
760 	}
761 
762 	// insist peer be connected
763 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
764 		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
765 		goto done;
766 	}
767 
768 	/* start any status interrupt transfer */
769 	if (dev->interrupt) {
770 		retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
771 		if (retval < 0) {
772 			netif_err(dev, ifup, dev->net,
773 				  "intr submit %d\n", retval);
774 			goto done;
775 		}
776 	}
777 
778 	set_bit(EVENT_DEV_OPEN, &dev->flags);
779 	netif_start_queue (net);
780 	netif_info(dev, ifup, dev->net,
781 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
782 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
783 		   dev->net->mtu,
784 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
785 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
786 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
787 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
788 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
789 		   "simple");
790 
791 	// delay posting reads until we're fully open
792 	tasklet_schedule (&dev->bh);
793 	if (info->manage_power) {
794 		retval = info->manage_power(dev, 1);
795 		if (retval < 0)
796 			goto done_manage_power_error;
797 		usb_autopm_put_interface(dev->intf);
798 	}
799 	return retval;
800 
801 done_manage_power_error:
802 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
803 done:
804 	usb_autopm_put_interface(dev->intf);
805 done_nopm:
806 	return retval;
807 }
808 EXPORT_SYMBOL_GPL(usbnet_open);
809 
810 /*-------------------------------------------------------------------------*/
811 
812 /* ethtool methods; minidrivers may need to add some more, but
813  * they'll probably want to use this base set.
814  */
815 
816 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
817 {
818 	struct usbnet *dev = netdev_priv(net);
819 
820 	if (!dev->mii.mdio_read)
821 		return -EOPNOTSUPP;
822 
823 	return mii_ethtool_gset(&dev->mii, cmd);
824 }
825 EXPORT_SYMBOL_GPL(usbnet_get_settings);
826 
827 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
828 {
829 	struct usbnet *dev = netdev_priv(net);
830 	int retval;
831 
832 	if (!dev->mii.mdio_write)
833 		return -EOPNOTSUPP;
834 
835 	retval = mii_ethtool_sset(&dev->mii, cmd);
836 
837 	/* link speed/duplex might have changed */
838 	if (dev->driver_info->link_reset)
839 		dev->driver_info->link_reset(dev);
840 
841 	return retval;
842 
843 }
844 EXPORT_SYMBOL_GPL(usbnet_set_settings);
845 
846 u32 usbnet_get_link (struct net_device *net)
847 {
848 	struct usbnet *dev = netdev_priv(net);
849 
850 	/* If a check_connect is defined, return its result */
851 	if (dev->driver_info->check_connect)
852 		return dev->driver_info->check_connect (dev) == 0;
853 
854 	/* if the device has mii operations, use those */
855 	if (dev->mii.mdio_read)
856 		return mii_link_ok(&dev->mii);
857 
858 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
859 	return ethtool_op_get_link(net);
860 }
861 EXPORT_SYMBOL_GPL(usbnet_get_link);
862 
863 int usbnet_nway_reset(struct net_device *net)
864 {
865 	struct usbnet *dev = netdev_priv(net);
866 
867 	if (!dev->mii.mdio_write)
868 		return -EOPNOTSUPP;
869 
870 	return mii_nway_restart(&dev->mii);
871 }
872 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
873 
874 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
875 {
876 	struct usbnet *dev = netdev_priv(net);
877 
878 	strlcpy (info->driver, dev->driver_name, sizeof info->driver);
879 	strlcpy (info->version, DRIVER_VERSION, sizeof info->version);
880 	strlcpy (info->fw_version, dev->driver_info->description,
881 		sizeof info->fw_version);
882 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
883 }
884 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
885 
886 u32 usbnet_get_msglevel (struct net_device *net)
887 {
888 	struct usbnet *dev = netdev_priv(net);
889 
890 	return dev->msg_enable;
891 }
892 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
893 
894 void usbnet_set_msglevel (struct net_device *net, u32 level)
895 {
896 	struct usbnet *dev = netdev_priv(net);
897 
898 	dev->msg_enable = level;
899 }
900 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
901 
902 /* drivers may override default ethtool_ops in their bind() routine */
903 static const struct ethtool_ops usbnet_ethtool_ops = {
904 	.get_settings		= usbnet_get_settings,
905 	.set_settings		= usbnet_set_settings,
906 	.get_link		= usbnet_get_link,
907 	.nway_reset		= usbnet_nway_reset,
908 	.get_drvinfo		= usbnet_get_drvinfo,
909 	.get_msglevel		= usbnet_get_msglevel,
910 	.set_msglevel		= usbnet_set_msglevel,
911 	.get_ts_info		= ethtool_op_get_ts_info,
912 };
913 
914 /*-------------------------------------------------------------------------*/
915 
916 /* work that cannot be done in interrupt context uses keventd.
917  *
918  * NOTE:  with 2.5 we could do more of this using completion callbacks,
919  * especially now that control transfers can be queued.
920  */
921 static void
922 kevent (struct work_struct *work)
923 {
924 	struct usbnet		*dev =
925 		container_of(work, struct usbnet, kevent);
926 	int			status;
927 
928 	/* usb_clear_halt() needs a thread context */
929 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
930 		unlink_urbs (dev, &dev->txq);
931 		status = usb_autopm_get_interface(dev->intf);
932 		if (status < 0)
933 			goto fail_pipe;
934 		status = usb_clear_halt (dev->udev, dev->out);
935 		usb_autopm_put_interface(dev->intf);
936 		if (status < 0 &&
937 		    status != -EPIPE &&
938 		    status != -ESHUTDOWN) {
939 			if (netif_msg_tx_err (dev))
940 fail_pipe:
941 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
942 					   status);
943 		} else {
944 			clear_bit (EVENT_TX_HALT, &dev->flags);
945 			if (status != -ESHUTDOWN)
946 				netif_wake_queue (dev->net);
947 		}
948 	}
949 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
950 		unlink_urbs (dev, &dev->rxq);
951 		status = usb_autopm_get_interface(dev->intf);
952 		if (status < 0)
953 			goto fail_halt;
954 		status = usb_clear_halt (dev->udev, dev->in);
955 		usb_autopm_put_interface(dev->intf);
956 		if (status < 0 &&
957 		    status != -EPIPE &&
958 		    status != -ESHUTDOWN) {
959 			if (netif_msg_rx_err (dev))
960 fail_halt:
961 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
962 					   status);
963 		} else {
964 			clear_bit (EVENT_RX_HALT, &dev->flags);
965 			tasklet_schedule (&dev->bh);
966 		}
967 	}
968 
969 	/* tasklet could resubmit itself forever if memory is tight */
970 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
971 		struct urb	*urb = NULL;
972 		int resched = 1;
973 
974 		if (netif_running (dev->net))
975 			urb = usb_alloc_urb (0, GFP_KERNEL);
976 		else
977 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
978 		if (urb != NULL) {
979 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
980 			status = usb_autopm_get_interface(dev->intf);
981 			if (status < 0) {
982 				usb_free_urb(urb);
983 				goto fail_lowmem;
984 			}
985 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
986 				resched = 0;
987 			usb_autopm_put_interface(dev->intf);
988 fail_lowmem:
989 			if (resched)
990 				tasklet_schedule (&dev->bh);
991 		}
992 	}
993 
994 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
995 		struct driver_info	*info = dev->driver_info;
996 		int			retval = 0;
997 
998 		clear_bit (EVENT_LINK_RESET, &dev->flags);
999 		status = usb_autopm_get_interface(dev->intf);
1000 		if (status < 0)
1001 			goto skip_reset;
1002 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1003 			usb_autopm_put_interface(dev->intf);
1004 skip_reset:
1005 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1006 				    retval,
1007 				    dev->udev->bus->bus_name,
1008 				    dev->udev->devpath,
1009 				    info->description);
1010 		} else {
1011 			usb_autopm_put_interface(dev->intf);
1012 		}
1013 	}
1014 
1015 	if (dev->flags)
1016 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1017 }
1018 
1019 /*-------------------------------------------------------------------------*/
1020 
1021 static void tx_complete (struct urb *urb)
1022 {
1023 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1024 	struct skb_data		*entry = (struct skb_data *) skb->cb;
1025 	struct usbnet		*dev = entry->dev;
1026 
1027 	if (urb->status == 0) {
1028 		if (!(dev->driver_info->flags & FLAG_MULTI_PACKET))
1029 			dev->net->stats.tx_packets++;
1030 		dev->net->stats.tx_bytes += entry->length;
1031 	} else {
1032 		dev->net->stats.tx_errors++;
1033 
1034 		switch (urb->status) {
1035 		case -EPIPE:
1036 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1037 			break;
1038 
1039 		/* software-driven interface shutdown */
1040 		case -ECONNRESET:		// async unlink
1041 		case -ESHUTDOWN:		// hardware gone
1042 			break;
1043 
1044 		// like rx, tx gets controller i/o faults during khubd delays
1045 		// and so it uses the same throttling mechanism.
1046 		case -EPROTO:
1047 		case -ETIME:
1048 		case -EILSEQ:
1049 			usb_mark_last_busy(dev->udev);
1050 			if (!timer_pending (&dev->delay)) {
1051 				mod_timer (&dev->delay,
1052 					jiffies + THROTTLE_JIFFIES);
1053 				netif_dbg(dev, link, dev->net,
1054 					  "tx throttle %d\n", urb->status);
1055 			}
1056 			netif_stop_queue (dev->net);
1057 			break;
1058 		default:
1059 			netif_dbg(dev, tx_err, dev->net,
1060 				  "tx err %d\n", entry->urb->status);
1061 			break;
1062 		}
1063 	}
1064 
1065 	usb_autopm_put_interface_async(dev->intf);
1066 	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1067 }
1068 
1069 /*-------------------------------------------------------------------------*/
1070 
1071 void usbnet_tx_timeout (struct net_device *net)
1072 {
1073 	struct usbnet		*dev = netdev_priv(net);
1074 
1075 	unlink_urbs (dev, &dev->txq);
1076 	tasklet_schedule (&dev->bh);
1077 
1078 	// FIXME: device recovery -- reset?
1079 }
1080 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1081 
1082 /*-------------------------------------------------------------------------*/
1083 
1084 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1085 				     struct net_device *net)
1086 {
1087 	struct usbnet		*dev = netdev_priv(net);
1088 	int			length;
1089 	struct urb		*urb = NULL;
1090 	struct skb_data		*entry;
1091 	struct driver_info	*info = dev->driver_info;
1092 	unsigned long		flags;
1093 	int retval;
1094 
1095 	if (skb)
1096 		skb_tx_timestamp(skb);
1097 
1098 	// some devices want funky USB-level framing, for
1099 	// win32 driver (usually) and/or hardware quirks
1100 	if (info->tx_fixup) {
1101 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1102 		if (!skb) {
1103 			if (netif_msg_tx_err(dev)) {
1104 				netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1105 				goto drop;
1106 			} else {
1107 				/* cdc_ncm collected packet; waits for more */
1108 				goto not_drop;
1109 			}
1110 		}
1111 	}
1112 	length = skb->len;
1113 
1114 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1115 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1116 		goto drop;
1117 	}
1118 
1119 	entry = (struct skb_data *) skb->cb;
1120 	entry->urb = urb;
1121 	entry->dev = dev;
1122 	entry->length = length;
1123 
1124 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1125 			skb->data, skb->len, tx_complete, skb);
1126 
1127 	/* don't assume the hardware handles USB_ZERO_PACKET
1128 	 * NOTE:  strictly conforming cdc-ether devices should expect
1129 	 * the ZLP here, but ignore the one-byte packet.
1130 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1131 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1132 	 * packet itself if needed.
1133 	 */
1134 	if (length % dev->maxpacket == 0) {
1135 		if (!(info->flags & FLAG_SEND_ZLP)) {
1136 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1137 				urb->transfer_buffer_length++;
1138 				if (skb_tailroom(skb)) {
1139 					skb->data[skb->len] = 0;
1140 					__skb_put(skb, 1);
1141 				}
1142 			}
1143 		} else
1144 			urb->transfer_flags |= URB_ZERO_PACKET;
1145 	}
1146 
1147 	spin_lock_irqsave(&dev->txq.lock, flags);
1148 	retval = usb_autopm_get_interface_async(dev->intf);
1149 	if (retval < 0) {
1150 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1151 		goto drop;
1152 	}
1153 
1154 #ifdef CONFIG_PM
1155 	/* if this triggers the device is still a sleep */
1156 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1157 		/* transmission will be done in resume */
1158 		usb_anchor_urb(urb, &dev->deferred);
1159 		/* no use to process more packets */
1160 		netif_stop_queue(net);
1161 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1162 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1163 		goto deferred;
1164 	}
1165 #endif
1166 
1167 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1168 	case -EPIPE:
1169 		netif_stop_queue (net);
1170 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1171 		usb_autopm_put_interface_async(dev->intf);
1172 		break;
1173 	default:
1174 		usb_autopm_put_interface_async(dev->intf);
1175 		netif_dbg(dev, tx_err, dev->net,
1176 			  "tx: submit urb err %d\n", retval);
1177 		break;
1178 	case 0:
1179 		net->trans_start = jiffies;
1180 		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1181 		if (dev->txq.qlen >= TX_QLEN (dev))
1182 			netif_stop_queue (net);
1183 	}
1184 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1185 
1186 	if (retval) {
1187 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1188 drop:
1189 		dev->net->stats.tx_dropped++;
1190 not_drop:
1191 		if (skb)
1192 			dev_kfree_skb_any (skb);
1193 		usb_free_urb (urb);
1194 	} else
1195 		netif_dbg(dev, tx_queued, dev->net,
1196 			  "> tx, len %d, type 0x%x\n", length, skb->protocol);
1197 #ifdef CONFIG_PM
1198 deferred:
1199 #endif
1200 	return NETDEV_TX_OK;
1201 }
1202 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1203 
1204 static void rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1205 {
1206 	struct urb	*urb;
1207 	int		i;
1208 
1209 	/* don't refill the queue all at once */
1210 	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1211 		urb = usb_alloc_urb(0, flags);
1212 		if (urb != NULL) {
1213 			if (rx_submit(dev, urb, flags) == -ENOLINK)
1214 				return;
1215 		}
1216 	}
1217 }
1218 
1219 /*-------------------------------------------------------------------------*/
1220 
1221 // tasklet (work deferred from completions, in_irq) or timer
1222 
1223 static void usbnet_bh (unsigned long param)
1224 {
1225 	struct usbnet		*dev = (struct usbnet *) param;
1226 	struct sk_buff		*skb;
1227 	struct skb_data		*entry;
1228 
1229 	while ((skb = skb_dequeue (&dev->done))) {
1230 		entry = (struct skb_data *) skb->cb;
1231 		switch (entry->state) {
1232 		case rx_done:
1233 			entry->state = rx_cleanup;
1234 			rx_process (dev, skb);
1235 			continue;
1236 		case tx_done:
1237 		case rx_cleanup:
1238 			usb_free_urb (entry->urb);
1239 			dev_kfree_skb (skb);
1240 			continue;
1241 		default:
1242 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1243 		}
1244 	}
1245 
1246 	// waiting for all pending urbs to complete?
1247 	if (dev->wait) {
1248 		if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
1249 			wake_up (dev->wait);
1250 		}
1251 
1252 	// or are we maybe short a few urbs?
1253 	} else if (netif_running (dev->net) &&
1254 		   netif_device_present (dev->net) &&
1255 		   !timer_pending (&dev->delay) &&
1256 		   !test_bit (EVENT_RX_HALT, &dev->flags)) {
1257 		int	temp = dev->rxq.qlen;
1258 
1259 		if (temp < RX_QLEN(dev)) {
1260 			rx_alloc_submit(dev, GFP_ATOMIC);
1261 			if (temp != dev->rxq.qlen)
1262 				netif_dbg(dev, link, dev->net,
1263 					  "rxqlen %d --> %d\n",
1264 					  temp, dev->rxq.qlen);
1265 			if (dev->rxq.qlen < RX_QLEN(dev))
1266 				tasklet_schedule (&dev->bh);
1267 		}
1268 		if (dev->txq.qlen < TX_QLEN (dev))
1269 			netif_wake_queue (dev->net);
1270 	}
1271 }
1272 
1273 
1274 /*-------------------------------------------------------------------------
1275  *
1276  * USB Device Driver support
1277  *
1278  *-------------------------------------------------------------------------*/
1279 
1280 // precondition: never called in_interrupt
1281 
1282 void usbnet_disconnect (struct usb_interface *intf)
1283 {
1284 	struct usbnet		*dev;
1285 	struct usb_device	*xdev;
1286 	struct net_device	*net;
1287 
1288 	dev = usb_get_intfdata(intf);
1289 	usb_set_intfdata(intf, NULL);
1290 	if (!dev)
1291 		return;
1292 
1293 	xdev = interface_to_usbdev (intf);
1294 
1295 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1296 		   intf->dev.driver->name,
1297 		   xdev->bus->bus_name, xdev->devpath,
1298 		   dev->driver_info->description);
1299 
1300 	net = dev->net;
1301 	unregister_netdev (net);
1302 
1303 	cancel_work_sync(&dev->kevent);
1304 
1305 	if (dev->driver_info->unbind)
1306 		dev->driver_info->unbind (dev, intf);
1307 
1308 	usb_kill_urb(dev->interrupt);
1309 	usb_free_urb(dev->interrupt);
1310 
1311 	free_netdev(net);
1312 }
1313 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1314 
1315 static const struct net_device_ops usbnet_netdev_ops = {
1316 	.ndo_open		= usbnet_open,
1317 	.ndo_stop		= usbnet_stop,
1318 	.ndo_start_xmit		= usbnet_start_xmit,
1319 	.ndo_tx_timeout		= usbnet_tx_timeout,
1320 	.ndo_change_mtu		= usbnet_change_mtu,
1321 	.ndo_set_mac_address 	= eth_mac_addr,
1322 	.ndo_validate_addr	= eth_validate_addr,
1323 };
1324 
1325 /*-------------------------------------------------------------------------*/
1326 
1327 // precondition: never called in_interrupt
1328 
1329 static struct device_type wlan_type = {
1330 	.name	= "wlan",
1331 };
1332 
1333 static struct device_type wwan_type = {
1334 	.name	= "wwan",
1335 };
1336 
1337 int
1338 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1339 {
1340 	struct usbnet			*dev;
1341 	struct net_device		*net;
1342 	struct usb_host_interface	*interface;
1343 	struct driver_info		*info;
1344 	struct usb_device		*xdev;
1345 	int				status;
1346 	const char			*name;
1347 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1348 
1349 	/* usbnet already took usb runtime pm, so have to enable the feature
1350 	 * for usb interface, otherwise usb_autopm_get_interface may return
1351 	 * failure if USB_SUSPEND(RUNTIME_PM) is enabled.
1352 	 */
1353 	if (!driver->supports_autosuspend) {
1354 		driver->supports_autosuspend = 1;
1355 		pm_runtime_enable(&udev->dev);
1356 	}
1357 
1358 	name = udev->dev.driver->name;
1359 	info = (struct driver_info *) prod->driver_info;
1360 	if (!info) {
1361 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1362 		return -ENODEV;
1363 	}
1364 	xdev = interface_to_usbdev (udev);
1365 	interface = udev->cur_altsetting;
1366 
1367 	status = -ENOMEM;
1368 
1369 	// set up our own records
1370 	net = alloc_etherdev(sizeof(*dev));
1371 	if (!net)
1372 		goto out;
1373 
1374 	/* netdev_printk() needs this so do it as early as possible */
1375 	SET_NETDEV_DEV(net, &udev->dev);
1376 
1377 	dev = netdev_priv(net);
1378 	dev->udev = xdev;
1379 	dev->intf = udev;
1380 	dev->driver_info = info;
1381 	dev->driver_name = name;
1382 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1383 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1384 	skb_queue_head_init (&dev->rxq);
1385 	skb_queue_head_init (&dev->txq);
1386 	skb_queue_head_init (&dev->done);
1387 	skb_queue_head_init(&dev->rxq_pause);
1388 	dev->bh.func = usbnet_bh;
1389 	dev->bh.data = (unsigned long) dev;
1390 	INIT_WORK (&dev->kevent, kevent);
1391 	init_usb_anchor(&dev->deferred);
1392 	dev->delay.function = usbnet_bh;
1393 	dev->delay.data = (unsigned long) dev;
1394 	init_timer (&dev->delay);
1395 	mutex_init (&dev->phy_mutex);
1396 
1397 	dev->net = net;
1398 	strcpy (net->name, "usb%d");
1399 	memcpy (net->dev_addr, node_id, sizeof node_id);
1400 
1401 	/* rx and tx sides can use different message sizes;
1402 	 * bind() should set rx_urb_size in that case.
1403 	 */
1404 	dev->hard_mtu = net->mtu + net->hard_header_len;
1405 #if 0
1406 // dma_supported() is deeply broken on almost all architectures
1407 	// possible with some EHCI controllers
1408 	if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1409 		net->features |= NETIF_F_HIGHDMA;
1410 #endif
1411 
1412 	net->netdev_ops = &usbnet_netdev_ops;
1413 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1414 	net->ethtool_ops = &usbnet_ethtool_ops;
1415 
1416 	// allow device-specific bind/init procedures
1417 	// NOTE net->name still not usable ...
1418 	if (info->bind) {
1419 		status = info->bind (dev, udev);
1420 		if (status < 0)
1421 			goto out1;
1422 
1423 		// heuristic:  "usb%d" for links we know are two-host,
1424 		// else "eth%d" when there's reasonable doubt.  userspace
1425 		// can rename the link if it knows better.
1426 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1427 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1428 		     (net->dev_addr [0] & 0x02) == 0))
1429 			strcpy (net->name, "eth%d");
1430 		/* WLAN devices should always be named "wlan%d" */
1431 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1432 			strcpy(net->name, "wlan%d");
1433 		/* WWAN devices should always be named "wwan%d" */
1434 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1435 			strcpy(net->name, "wwan%d");
1436 
1437 		/* maybe the remote can't receive an Ethernet MTU */
1438 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1439 			net->mtu = dev->hard_mtu - net->hard_header_len;
1440 	} else if (!info->in || !info->out)
1441 		status = usbnet_get_endpoints (dev, udev);
1442 	else {
1443 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1444 		dev->out = usb_sndbulkpipe (xdev, info->out);
1445 		if (!(info->flags & FLAG_NO_SETINT))
1446 			status = usb_set_interface (xdev,
1447 				interface->desc.bInterfaceNumber,
1448 				interface->desc.bAlternateSetting);
1449 		else
1450 			status = 0;
1451 
1452 	}
1453 	if (status >= 0 && dev->status)
1454 		status = init_status (dev, udev);
1455 	if (status < 0)
1456 		goto out3;
1457 
1458 	if (!dev->rx_urb_size)
1459 		dev->rx_urb_size = dev->hard_mtu;
1460 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1461 
1462 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1463 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1464 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1465 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1466 
1467 	status = register_netdev (net);
1468 	if (status)
1469 		goto out4;
1470 	netif_info(dev, probe, dev->net,
1471 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1472 		   udev->dev.driver->name,
1473 		   xdev->bus->bus_name, xdev->devpath,
1474 		   dev->driver_info->description,
1475 		   net->dev_addr);
1476 
1477 	// ok, it's ready to go.
1478 	usb_set_intfdata (udev, dev);
1479 
1480 	netif_device_attach (net);
1481 
1482 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1483 		netif_carrier_off(net);
1484 
1485 	return 0;
1486 
1487 out4:
1488 	usb_free_urb(dev->interrupt);
1489 out3:
1490 	if (info->unbind)
1491 		info->unbind (dev, udev);
1492 out1:
1493 	free_netdev(net);
1494 out:
1495 	return status;
1496 }
1497 EXPORT_SYMBOL_GPL(usbnet_probe);
1498 
1499 /*-------------------------------------------------------------------------*/
1500 
1501 /*
1502  * suspend the whole driver as soon as the first interface is suspended
1503  * resume only when the last interface is resumed
1504  */
1505 
1506 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1507 {
1508 	struct usbnet		*dev = usb_get_intfdata(intf);
1509 
1510 	if (!dev->suspend_count++) {
1511 		spin_lock_irq(&dev->txq.lock);
1512 		/* don't autosuspend while transmitting */
1513 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1514 			dev->suspend_count--;
1515 			spin_unlock_irq(&dev->txq.lock);
1516 			return -EBUSY;
1517 		} else {
1518 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1519 			spin_unlock_irq(&dev->txq.lock);
1520 		}
1521 		/*
1522 		 * accelerate emptying of the rx and queues, to avoid
1523 		 * having everything error out.
1524 		 */
1525 		netif_device_detach (dev->net);
1526 		usbnet_terminate_urbs(dev);
1527 		usb_kill_urb(dev->interrupt);
1528 
1529 		/*
1530 		 * reattach so runtime management can use and
1531 		 * wake the device
1532 		 */
1533 		netif_device_attach (dev->net);
1534 	}
1535 	return 0;
1536 }
1537 EXPORT_SYMBOL_GPL(usbnet_suspend);
1538 
1539 int usbnet_resume (struct usb_interface *intf)
1540 {
1541 	struct usbnet		*dev = usb_get_intfdata(intf);
1542 	struct sk_buff          *skb;
1543 	struct urb              *res;
1544 	int                     retval;
1545 
1546 	if (!--dev->suspend_count) {
1547 		/* resume interrupt URBs */
1548 		if (dev->interrupt && test_bit(EVENT_DEV_OPEN, &dev->flags))
1549 			usb_submit_urb(dev->interrupt, GFP_NOIO);
1550 
1551 		spin_lock_irq(&dev->txq.lock);
1552 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1553 
1554 			skb = (struct sk_buff *)res->context;
1555 			retval = usb_submit_urb(res, GFP_ATOMIC);
1556 			if (retval < 0) {
1557 				dev_kfree_skb_any(skb);
1558 				usb_free_urb(res);
1559 				usb_autopm_put_interface_async(dev->intf);
1560 			} else {
1561 				dev->net->trans_start = jiffies;
1562 				__skb_queue_tail(&dev->txq, skb);
1563 			}
1564 		}
1565 
1566 		smp_mb();
1567 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1568 		spin_unlock_irq(&dev->txq.lock);
1569 
1570 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1571 			/* handle remote wakeup ASAP */
1572 			if (!dev->wait &&
1573 				netif_device_present(dev->net) &&
1574 				!timer_pending(&dev->delay) &&
1575 				!test_bit(EVENT_RX_HALT, &dev->flags))
1576 					rx_alloc_submit(dev, GFP_NOIO);
1577 
1578 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1579 				netif_tx_wake_all_queues(dev->net);
1580 			tasklet_schedule (&dev->bh);
1581 		}
1582 	}
1583 	return 0;
1584 }
1585 EXPORT_SYMBOL_GPL(usbnet_resume);
1586 
1587 
1588 /*-------------------------------------------------------------------------*/
1589 
1590 static int __init usbnet_init(void)
1591 {
1592 	/* Compiler should optimize this out. */
1593 	BUILD_BUG_ON(
1594 		FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
1595 
1596 	eth_random_addr(node_id);
1597 	return 0;
1598 }
1599 module_init(usbnet_init);
1600 
1601 static void __exit usbnet_exit(void)
1602 {
1603 }
1604 module_exit(usbnet_exit);
1605 
1606 MODULE_AUTHOR("David Brownell");
1607 MODULE_DESCRIPTION("USB network driver framework");
1608 MODULE_LICENSE("GPL");
1609