xref: /linux/drivers/net/usb/usbnet.c (revision 0d456bad36d42d16022be045c8a53ddbb59ee478)
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 		if (net_ratelimit())
364 			netdev_err(dev->net, "kevent %d may have been dropped\n", work);
365 	} else {
366 		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
367 	}
368 }
369 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
370 
371 /*-------------------------------------------------------------------------*/
372 
373 static void rx_complete (struct urb *urb);
374 
375 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
376 {
377 	struct sk_buff		*skb;
378 	struct skb_data		*entry;
379 	int			retval = 0;
380 	unsigned long		lockflags;
381 	size_t			size = dev->rx_urb_size;
382 
383 	skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
384 	if (!skb) {
385 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
386 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
387 		usb_free_urb (urb);
388 		return -ENOMEM;
389 	}
390 
391 	entry = (struct skb_data *) skb->cb;
392 	entry->urb = urb;
393 	entry->dev = dev;
394 	entry->length = 0;
395 
396 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
397 		skb->data, size, rx_complete, skb);
398 
399 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
400 
401 	if (netif_running (dev->net) &&
402 	    netif_device_present (dev->net) &&
403 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
404 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
405 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
406 		case -EPIPE:
407 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
408 			break;
409 		case -ENOMEM:
410 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
411 			break;
412 		case -ENODEV:
413 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
414 			netif_device_detach (dev->net);
415 			break;
416 		case -EHOSTUNREACH:
417 			retval = -ENOLINK;
418 			break;
419 		default:
420 			netif_dbg(dev, rx_err, dev->net,
421 				  "rx submit, %d\n", retval);
422 			tasklet_schedule (&dev->bh);
423 			break;
424 		case 0:
425 			__usbnet_queue_skb(&dev->rxq, skb, rx_start);
426 		}
427 	} else {
428 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
429 		retval = -ENOLINK;
430 	}
431 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
432 	if (retval) {
433 		dev_kfree_skb_any (skb);
434 		usb_free_urb (urb);
435 	}
436 	return retval;
437 }
438 
439 
440 /*-------------------------------------------------------------------------*/
441 
442 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
443 {
444 	if (dev->driver_info->rx_fixup &&
445 	    !dev->driver_info->rx_fixup (dev, skb)) {
446 		/* With RX_ASSEMBLE, rx_fixup() must update counters */
447 		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
448 			dev->net->stats.rx_errors++;
449 		goto done;
450 	}
451 	// else network stack removes extra byte if we forced a short packet
452 
453 	if (skb->len) {
454 		/* all data was already cloned from skb inside the driver */
455 		if (dev->driver_info->flags & FLAG_MULTI_PACKET)
456 			dev_kfree_skb_any(skb);
457 		else
458 			usbnet_skb_return(dev, skb);
459 		return;
460 	}
461 
462 	netif_dbg(dev, rx_err, dev->net, "drop\n");
463 	dev->net->stats.rx_errors++;
464 done:
465 	skb_queue_tail(&dev->done, skb);
466 }
467 
468 /*-------------------------------------------------------------------------*/
469 
470 static void rx_complete (struct urb *urb)
471 {
472 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
473 	struct skb_data		*entry = (struct skb_data *) skb->cb;
474 	struct usbnet		*dev = entry->dev;
475 	int			urb_status = urb->status;
476 	enum skb_state		state;
477 
478 	skb_put (skb, urb->actual_length);
479 	state = rx_done;
480 	entry->urb = NULL;
481 
482 	switch (urb_status) {
483 	/* success */
484 	case 0:
485 		if (skb->len < dev->net->hard_header_len) {
486 			state = rx_cleanup;
487 			dev->net->stats.rx_errors++;
488 			dev->net->stats.rx_length_errors++;
489 			netif_dbg(dev, rx_err, dev->net,
490 				  "rx length %d\n", skb->len);
491 		}
492 		break;
493 
494 	/* stalls need manual reset. this is rare ... except that
495 	 * when going through USB 2.0 TTs, unplug appears this way.
496 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
497 	 * storm, recovering as needed.
498 	 */
499 	case -EPIPE:
500 		dev->net->stats.rx_errors++;
501 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
502 		// FALLTHROUGH
503 
504 	/* software-driven interface shutdown */
505 	case -ECONNRESET:		/* async unlink */
506 	case -ESHUTDOWN:		/* hardware gone */
507 		netif_dbg(dev, ifdown, dev->net,
508 			  "rx shutdown, code %d\n", urb_status);
509 		goto block;
510 
511 	/* we get controller i/o faults during khubd disconnect() delays.
512 	 * throttle down resubmits, to avoid log floods; just temporarily,
513 	 * so we still recover when the fault isn't a khubd delay.
514 	 */
515 	case -EPROTO:
516 	case -ETIME:
517 	case -EILSEQ:
518 		dev->net->stats.rx_errors++;
519 		if (!timer_pending (&dev->delay)) {
520 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
521 			netif_dbg(dev, link, dev->net,
522 				  "rx throttle %d\n", urb_status);
523 		}
524 block:
525 		state = rx_cleanup;
526 		entry->urb = urb;
527 		urb = NULL;
528 		break;
529 
530 	/* data overrun ... flush fifo? */
531 	case -EOVERFLOW:
532 		dev->net->stats.rx_over_errors++;
533 		// FALLTHROUGH
534 
535 	default:
536 		state = rx_cleanup;
537 		dev->net->stats.rx_errors++;
538 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
539 		break;
540 	}
541 
542 	state = defer_bh(dev, skb, &dev->rxq, state);
543 
544 	if (urb) {
545 		if (netif_running (dev->net) &&
546 		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
547 		    state != unlink_start) {
548 			rx_submit (dev, urb, GFP_ATOMIC);
549 			usb_mark_last_busy(dev->udev);
550 			return;
551 		}
552 		usb_free_urb (urb);
553 	}
554 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
555 }
556 
557 /*-------------------------------------------------------------------------*/
558 void usbnet_pause_rx(struct usbnet *dev)
559 {
560 	set_bit(EVENT_RX_PAUSED, &dev->flags);
561 
562 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
563 }
564 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
565 
566 void usbnet_resume_rx(struct usbnet *dev)
567 {
568 	struct sk_buff *skb;
569 	int num = 0;
570 
571 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
572 
573 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
574 		usbnet_skb_return(dev, skb);
575 		num++;
576 	}
577 
578 	tasklet_schedule(&dev->bh);
579 
580 	netif_dbg(dev, rx_status, dev->net,
581 		  "paused rx queue disabled, %d skbs requeued\n", num);
582 }
583 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
584 
585 void usbnet_purge_paused_rxq(struct usbnet *dev)
586 {
587 	skb_queue_purge(&dev->rxq_pause);
588 }
589 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
590 
591 /*-------------------------------------------------------------------------*/
592 
593 // unlink pending rx/tx; completion handlers do all other cleanup
594 
595 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
596 {
597 	unsigned long		flags;
598 	struct sk_buff		*skb;
599 	int			count = 0;
600 
601 	spin_lock_irqsave (&q->lock, flags);
602 	while (!skb_queue_empty(q)) {
603 		struct skb_data		*entry;
604 		struct urb		*urb;
605 		int			retval;
606 
607 		skb_queue_walk(q, skb) {
608 			entry = (struct skb_data *) skb->cb;
609 			if (entry->state != unlink_start)
610 				goto found;
611 		}
612 		break;
613 found:
614 		entry->state = unlink_start;
615 		urb = entry->urb;
616 
617 		/*
618 		 * Get reference count of the URB to avoid it to be
619 		 * freed during usb_unlink_urb, which may trigger
620 		 * use-after-free problem inside usb_unlink_urb since
621 		 * usb_unlink_urb is always racing with .complete
622 		 * handler(include defer_bh).
623 		 */
624 		usb_get_urb(urb);
625 		spin_unlock_irqrestore(&q->lock, flags);
626 		// during some PM-driven resume scenarios,
627 		// these (async) unlinks complete immediately
628 		retval = usb_unlink_urb (urb);
629 		if (retval != -EINPROGRESS && retval != 0)
630 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
631 		else
632 			count++;
633 		usb_put_urb(urb);
634 		spin_lock_irqsave(&q->lock, flags);
635 	}
636 	spin_unlock_irqrestore (&q->lock, flags);
637 	return count;
638 }
639 
640 // Flush all pending rx urbs
641 // minidrivers may need to do this when the MTU changes
642 
643 void usbnet_unlink_rx_urbs(struct usbnet *dev)
644 {
645 	if (netif_running(dev->net)) {
646 		(void) unlink_urbs (dev, &dev->rxq);
647 		tasklet_schedule(&dev->bh);
648 	}
649 }
650 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
651 
652 /*-------------------------------------------------------------------------*/
653 
654 // precondition: never called in_interrupt
655 static void usbnet_terminate_urbs(struct usbnet *dev)
656 {
657 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
658 	DECLARE_WAITQUEUE(wait, current);
659 	int temp;
660 
661 	/* ensure there are no more active urbs */
662 	add_wait_queue(&unlink_wakeup, &wait);
663 	set_current_state(TASK_UNINTERRUPTIBLE);
664 	dev->wait = &unlink_wakeup;
665 	temp = unlink_urbs(dev, &dev->txq) +
666 		unlink_urbs(dev, &dev->rxq);
667 
668 	/* maybe wait for deletions to finish. */
669 	while (!skb_queue_empty(&dev->rxq)
670 		&& !skb_queue_empty(&dev->txq)
671 		&& !skb_queue_empty(&dev->done)) {
672 			schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
673 			set_current_state(TASK_UNINTERRUPTIBLE);
674 			netif_dbg(dev, ifdown, dev->net,
675 				  "waited for %d urb completions\n", temp);
676 	}
677 	set_current_state(TASK_RUNNING);
678 	dev->wait = NULL;
679 	remove_wait_queue(&unlink_wakeup, &wait);
680 }
681 
682 int usbnet_stop (struct net_device *net)
683 {
684 	struct usbnet		*dev = netdev_priv(net);
685 	struct driver_info	*info = dev->driver_info;
686 	int			retval;
687 
688 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
689 	netif_stop_queue (net);
690 
691 	netif_info(dev, ifdown, dev->net,
692 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
693 		   net->stats.rx_packets, net->stats.tx_packets,
694 		   net->stats.rx_errors, net->stats.tx_errors);
695 
696 	/* allow minidriver to stop correctly (wireless devices to turn off
697 	 * radio etc) */
698 	if (info->stop) {
699 		retval = info->stop(dev);
700 		if (retval < 0)
701 			netif_info(dev, ifdown, dev->net,
702 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
703 				   retval,
704 				   dev->udev->bus->bus_name, dev->udev->devpath,
705 				   info->description);
706 	}
707 
708 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
709 		usbnet_terminate_urbs(dev);
710 
711 	usb_kill_urb(dev->interrupt);
712 
713 	usbnet_purge_paused_rxq(dev);
714 
715 	/* deferred work (task, timer, softirq) must also stop.
716 	 * can't flush_scheduled_work() until we drop rtnl (later),
717 	 * else workers could deadlock; so make workers a NOP.
718 	 */
719 	dev->flags = 0;
720 	del_timer_sync (&dev->delay);
721 	tasklet_kill (&dev->bh);
722 	if (info->manage_power)
723 		info->manage_power(dev, 0);
724 	else
725 		usb_autopm_put_interface(dev->intf);
726 
727 	return 0;
728 }
729 EXPORT_SYMBOL_GPL(usbnet_stop);
730 
731 /*-------------------------------------------------------------------------*/
732 
733 // posts reads, and enables write queuing
734 
735 // precondition: never called in_interrupt
736 
737 int usbnet_open (struct net_device *net)
738 {
739 	struct usbnet		*dev = netdev_priv(net);
740 	int			retval;
741 	struct driver_info	*info = dev->driver_info;
742 
743 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
744 		netif_info(dev, ifup, dev->net,
745 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
746 			   retval,
747 			   dev->udev->bus->bus_name,
748 			   dev->udev->devpath,
749 			   info->description);
750 		goto done_nopm;
751 	}
752 
753 	// put into "known safe" state
754 	if (info->reset && (retval = info->reset (dev)) < 0) {
755 		netif_info(dev, ifup, dev->net,
756 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
757 			   retval,
758 			   dev->udev->bus->bus_name,
759 			   dev->udev->devpath,
760 			   info->description);
761 		goto done;
762 	}
763 
764 	// insist peer be connected
765 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
766 		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
767 		goto done;
768 	}
769 
770 	/* start any status interrupt transfer */
771 	if (dev->interrupt) {
772 		retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
773 		if (retval < 0) {
774 			netif_err(dev, ifup, dev->net,
775 				  "intr submit %d\n", retval);
776 			goto done;
777 		}
778 	}
779 
780 	set_bit(EVENT_DEV_OPEN, &dev->flags);
781 	netif_start_queue (net);
782 	netif_info(dev, ifup, dev->net,
783 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
784 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
785 		   dev->net->mtu,
786 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
787 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
788 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
789 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
790 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
791 		   "simple");
792 
793 	// delay posting reads until we're fully open
794 	tasklet_schedule (&dev->bh);
795 	if (info->manage_power) {
796 		retval = info->manage_power(dev, 1);
797 		if (retval < 0)
798 			goto done_manage_power_error;
799 		usb_autopm_put_interface(dev->intf);
800 	}
801 	return retval;
802 
803 done_manage_power_error:
804 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
805 done:
806 	usb_autopm_put_interface(dev->intf);
807 done_nopm:
808 	return retval;
809 }
810 EXPORT_SYMBOL_GPL(usbnet_open);
811 
812 /*-------------------------------------------------------------------------*/
813 
814 /* ethtool methods; minidrivers may need to add some more, but
815  * they'll probably want to use this base set.
816  */
817 
818 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
819 {
820 	struct usbnet *dev = netdev_priv(net);
821 
822 	if (!dev->mii.mdio_read)
823 		return -EOPNOTSUPP;
824 
825 	return mii_ethtool_gset(&dev->mii, cmd);
826 }
827 EXPORT_SYMBOL_GPL(usbnet_get_settings);
828 
829 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
830 {
831 	struct usbnet *dev = netdev_priv(net);
832 	int retval;
833 
834 	if (!dev->mii.mdio_write)
835 		return -EOPNOTSUPP;
836 
837 	retval = mii_ethtool_sset(&dev->mii, cmd);
838 
839 	/* link speed/duplex might have changed */
840 	if (dev->driver_info->link_reset)
841 		dev->driver_info->link_reset(dev);
842 
843 	return retval;
844 
845 }
846 EXPORT_SYMBOL_GPL(usbnet_set_settings);
847 
848 u32 usbnet_get_link (struct net_device *net)
849 {
850 	struct usbnet *dev = netdev_priv(net);
851 
852 	/* If a check_connect is defined, return its result */
853 	if (dev->driver_info->check_connect)
854 		return dev->driver_info->check_connect (dev) == 0;
855 
856 	/* if the device has mii operations, use those */
857 	if (dev->mii.mdio_read)
858 		return mii_link_ok(&dev->mii);
859 
860 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
861 	return ethtool_op_get_link(net);
862 }
863 EXPORT_SYMBOL_GPL(usbnet_get_link);
864 
865 int usbnet_nway_reset(struct net_device *net)
866 {
867 	struct usbnet *dev = netdev_priv(net);
868 
869 	if (!dev->mii.mdio_write)
870 		return -EOPNOTSUPP;
871 
872 	return mii_nway_restart(&dev->mii);
873 }
874 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
875 
876 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
877 {
878 	struct usbnet *dev = netdev_priv(net);
879 
880 	strlcpy (info->driver, dev->driver_name, sizeof info->driver);
881 	strlcpy (info->version, DRIVER_VERSION, sizeof info->version);
882 	strlcpy (info->fw_version, dev->driver_info->description,
883 		sizeof info->fw_version);
884 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
885 }
886 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
887 
888 u32 usbnet_get_msglevel (struct net_device *net)
889 {
890 	struct usbnet *dev = netdev_priv(net);
891 
892 	return dev->msg_enable;
893 }
894 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
895 
896 void usbnet_set_msglevel (struct net_device *net, u32 level)
897 {
898 	struct usbnet *dev = netdev_priv(net);
899 
900 	dev->msg_enable = level;
901 }
902 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
903 
904 /* drivers may override default ethtool_ops in their bind() routine */
905 static const struct ethtool_ops usbnet_ethtool_ops = {
906 	.get_settings		= usbnet_get_settings,
907 	.set_settings		= usbnet_set_settings,
908 	.get_link		= usbnet_get_link,
909 	.nway_reset		= usbnet_nway_reset,
910 	.get_drvinfo		= usbnet_get_drvinfo,
911 	.get_msglevel		= usbnet_get_msglevel,
912 	.set_msglevel		= usbnet_set_msglevel,
913 	.get_ts_info		= ethtool_op_get_ts_info,
914 };
915 
916 /*-------------------------------------------------------------------------*/
917 
918 /* work that cannot be done in interrupt context uses keventd.
919  *
920  * NOTE:  with 2.5 we could do more of this using completion callbacks,
921  * especially now that control transfers can be queued.
922  */
923 static void
924 kevent (struct work_struct *work)
925 {
926 	struct usbnet		*dev =
927 		container_of(work, struct usbnet, kevent);
928 	int			status;
929 
930 	/* usb_clear_halt() needs a thread context */
931 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
932 		unlink_urbs (dev, &dev->txq);
933 		status = usb_autopm_get_interface(dev->intf);
934 		if (status < 0)
935 			goto fail_pipe;
936 		status = usb_clear_halt (dev->udev, dev->out);
937 		usb_autopm_put_interface(dev->intf);
938 		if (status < 0 &&
939 		    status != -EPIPE &&
940 		    status != -ESHUTDOWN) {
941 			if (netif_msg_tx_err (dev))
942 fail_pipe:
943 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
944 					   status);
945 		} else {
946 			clear_bit (EVENT_TX_HALT, &dev->flags);
947 			if (status != -ESHUTDOWN)
948 				netif_wake_queue (dev->net);
949 		}
950 	}
951 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
952 		unlink_urbs (dev, &dev->rxq);
953 		status = usb_autopm_get_interface(dev->intf);
954 		if (status < 0)
955 			goto fail_halt;
956 		status = usb_clear_halt (dev->udev, dev->in);
957 		usb_autopm_put_interface(dev->intf);
958 		if (status < 0 &&
959 		    status != -EPIPE &&
960 		    status != -ESHUTDOWN) {
961 			if (netif_msg_rx_err (dev))
962 fail_halt:
963 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
964 					   status);
965 		} else {
966 			clear_bit (EVENT_RX_HALT, &dev->flags);
967 			tasklet_schedule (&dev->bh);
968 		}
969 	}
970 
971 	/* tasklet could resubmit itself forever if memory is tight */
972 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
973 		struct urb	*urb = NULL;
974 		int resched = 1;
975 
976 		if (netif_running (dev->net))
977 			urb = usb_alloc_urb (0, GFP_KERNEL);
978 		else
979 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
980 		if (urb != NULL) {
981 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
982 			status = usb_autopm_get_interface(dev->intf);
983 			if (status < 0) {
984 				usb_free_urb(urb);
985 				goto fail_lowmem;
986 			}
987 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
988 				resched = 0;
989 			usb_autopm_put_interface(dev->intf);
990 fail_lowmem:
991 			if (resched)
992 				tasklet_schedule (&dev->bh);
993 		}
994 	}
995 
996 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
997 		struct driver_info	*info = dev->driver_info;
998 		int			retval = 0;
999 
1000 		clear_bit (EVENT_LINK_RESET, &dev->flags);
1001 		status = usb_autopm_get_interface(dev->intf);
1002 		if (status < 0)
1003 			goto skip_reset;
1004 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1005 			usb_autopm_put_interface(dev->intf);
1006 skip_reset:
1007 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1008 				    retval,
1009 				    dev->udev->bus->bus_name,
1010 				    dev->udev->devpath,
1011 				    info->description);
1012 		} else {
1013 			usb_autopm_put_interface(dev->intf);
1014 		}
1015 	}
1016 
1017 	if (dev->flags)
1018 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1019 }
1020 
1021 /*-------------------------------------------------------------------------*/
1022 
1023 static void tx_complete (struct urb *urb)
1024 {
1025 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1026 	struct skb_data		*entry = (struct skb_data *) skb->cb;
1027 	struct usbnet		*dev = entry->dev;
1028 
1029 	if (urb->status == 0) {
1030 		if (!(dev->driver_info->flags & FLAG_MULTI_PACKET))
1031 			dev->net->stats.tx_packets++;
1032 		dev->net->stats.tx_bytes += entry->length;
1033 	} else {
1034 		dev->net->stats.tx_errors++;
1035 
1036 		switch (urb->status) {
1037 		case -EPIPE:
1038 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1039 			break;
1040 
1041 		/* software-driven interface shutdown */
1042 		case -ECONNRESET:		// async unlink
1043 		case -ESHUTDOWN:		// hardware gone
1044 			break;
1045 
1046 		// like rx, tx gets controller i/o faults during khubd delays
1047 		// and so it uses the same throttling mechanism.
1048 		case -EPROTO:
1049 		case -ETIME:
1050 		case -EILSEQ:
1051 			usb_mark_last_busy(dev->udev);
1052 			if (!timer_pending (&dev->delay)) {
1053 				mod_timer (&dev->delay,
1054 					jiffies + THROTTLE_JIFFIES);
1055 				netif_dbg(dev, link, dev->net,
1056 					  "tx throttle %d\n", urb->status);
1057 			}
1058 			netif_stop_queue (dev->net);
1059 			break;
1060 		default:
1061 			netif_dbg(dev, tx_err, dev->net,
1062 				  "tx err %d\n", entry->urb->status);
1063 			break;
1064 		}
1065 	}
1066 
1067 	usb_autopm_put_interface_async(dev->intf);
1068 	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1069 }
1070 
1071 /*-------------------------------------------------------------------------*/
1072 
1073 void usbnet_tx_timeout (struct net_device *net)
1074 {
1075 	struct usbnet		*dev = netdev_priv(net);
1076 
1077 	unlink_urbs (dev, &dev->txq);
1078 	tasklet_schedule (&dev->bh);
1079 
1080 	// FIXME: device recovery -- reset?
1081 }
1082 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1083 
1084 /*-------------------------------------------------------------------------*/
1085 
1086 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1087 				     struct net_device *net)
1088 {
1089 	struct usbnet		*dev = netdev_priv(net);
1090 	int			length;
1091 	struct urb		*urb = NULL;
1092 	struct skb_data		*entry;
1093 	struct driver_info	*info = dev->driver_info;
1094 	unsigned long		flags;
1095 	int retval;
1096 
1097 	if (skb)
1098 		skb_tx_timestamp(skb);
1099 
1100 	// some devices want funky USB-level framing, for
1101 	// win32 driver (usually) and/or hardware quirks
1102 	if (info->tx_fixup) {
1103 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1104 		if (!skb) {
1105 			if (netif_msg_tx_err(dev)) {
1106 				netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1107 				goto drop;
1108 			} else {
1109 				/* cdc_ncm collected packet; waits for more */
1110 				goto not_drop;
1111 			}
1112 		}
1113 	}
1114 	length = skb->len;
1115 
1116 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1117 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1118 		goto drop;
1119 	}
1120 
1121 	entry = (struct skb_data *) skb->cb;
1122 	entry->urb = urb;
1123 	entry->dev = dev;
1124 	entry->length = length;
1125 
1126 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1127 			skb->data, skb->len, tx_complete, skb);
1128 
1129 	/* don't assume the hardware handles USB_ZERO_PACKET
1130 	 * NOTE:  strictly conforming cdc-ether devices should expect
1131 	 * the ZLP here, but ignore the one-byte packet.
1132 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1133 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1134 	 * packet itself if needed.
1135 	 */
1136 	if (length % dev->maxpacket == 0) {
1137 		if (!(info->flags & FLAG_SEND_ZLP)) {
1138 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1139 				urb->transfer_buffer_length++;
1140 				if (skb_tailroom(skb)) {
1141 					skb->data[skb->len] = 0;
1142 					__skb_put(skb, 1);
1143 				}
1144 			}
1145 		} else
1146 			urb->transfer_flags |= URB_ZERO_PACKET;
1147 	}
1148 
1149 	spin_lock_irqsave(&dev->txq.lock, flags);
1150 	retval = usb_autopm_get_interface_async(dev->intf);
1151 	if (retval < 0) {
1152 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1153 		goto drop;
1154 	}
1155 
1156 #ifdef CONFIG_PM
1157 	/* if this triggers the device is still a sleep */
1158 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1159 		/* transmission will be done in resume */
1160 		usb_anchor_urb(urb, &dev->deferred);
1161 		/* no use to process more packets */
1162 		netif_stop_queue(net);
1163 		usb_put_urb(urb);
1164 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1165 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1166 		goto deferred;
1167 	}
1168 #endif
1169 
1170 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1171 	case -EPIPE:
1172 		netif_stop_queue (net);
1173 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1174 		usb_autopm_put_interface_async(dev->intf);
1175 		break;
1176 	default:
1177 		usb_autopm_put_interface_async(dev->intf);
1178 		netif_dbg(dev, tx_err, dev->net,
1179 			  "tx: submit urb err %d\n", retval);
1180 		break;
1181 	case 0:
1182 		net->trans_start = jiffies;
1183 		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1184 		if (dev->txq.qlen >= TX_QLEN (dev))
1185 			netif_stop_queue (net);
1186 	}
1187 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1188 
1189 	if (retval) {
1190 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1191 drop:
1192 		dev->net->stats.tx_dropped++;
1193 not_drop:
1194 		if (skb)
1195 			dev_kfree_skb_any (skb);
1196 		usb_free_urb (urb);
1197 	} else
1198 		netif_dbg(dev, tx_queued, dev->net,
1199 			  "> tx, len %d, type 0x%x\n", length, skb->protocol);
1200 #ifdef CONFIG_PM
1201 deferred:
1202 #endif
1203 	return NETDEV_TX_OK;
1204 }
1205 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1206 
1207 static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1208 {
1209 	struct urb	*urb;
1210 	int		i;
1211 	int		ret = 0;
1212 
1213 	/* don't refill the queue all at once */
1214 	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1215 		urb = usb_alloc_urb(0, flags);
1216 		if (urb != NULL) {
1217 			ret = rx_submit(dev, urb, flags);
1218 			if (ret)
1219 				goto err;
1220 		} else {
1221 			ret = -ENOMEM;
1222 			goto err;
1223 		}
1224 	}
1225 err:
1226 	return ret;
1227 }
1228 
1229 /*-------------------------------------------------------------------------*/
1230 
1231 // tasklet (work deferred from completions, in_irq) or timer
1232 
1233 static void usbnet_bh (unsigned long param)
1234 {
1235 	struct usbnet		*dev = (struct usbnet *) param;
1236 	struct sk_buff		*skb;
1237 	struct skb_data		*entry;
1238 
1239 	while ((skb = skb_dequeue (&dev->done))) {
1240 		entry = (struct skb_data *) skb->cb;
1241 		switch (entry->state) {
1242 		case rx_done:
1243 			entry->state = rx_cleanup;
1244 			rx_process (dev, skb);
1245 			continue;
1246 		case tx_done:
1247 		case rx_cleanup:
1248 			usb_free_urb (entry->urb);
1249 			dev_kfree_skb (skb);
1250 			continue;
1251 		default:
1252 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1253 		}
1254 	}
1255 
1256 	// waiting for all pending urbs to complete?
1257 	if (dev->wait) {
1258 		if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
1259 			wake_up (dev->wait);
1260 		}
1261 
1262 	// or are we maybe short a few urbs?
1263 	} else if (netif_running (dev->net) &&
1264 		   netif_device_present (dev->net) &&
1265 		   !timer_pending (&dev->delay) &&
1266 		   !test_bit (EVENT_RX_HALT, &dev->flags)) {
1267 		int	temp = dev->rxq.qlen;
1268 
1269 		if (temp < RX_QLEN(dev)) {
1270 			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1271 				return;
1272 			if (temp != dev->rxq.qlen)
1273 				netif_dbg(dev, link, dev->net,
1274 					  "rxqlen %d --> %d\n",
1275 					  temp, dev->rxq.qlen);
1276 			if (dev->rxq.qlen < RX_QLEN(dev))
1277 				tasklet_schedule (&dev->bh);
1278 		}
1279 		if (dev->txq.qlen < TX_QLEN (dev))
1280 			netif_wake_queue (dev->net);
1281 	}
1282 }
1283 
1284 
1285 /*-------------------------------------------------------------------------
1286  *
1287  * USB Device Driver support
1288  *
1289  *-------------------------------------------------------------------------*/
1290 
1291 // precondition: never called in_interrupt
1292 
1293 void usbnet_disconnect (struct usb_interface *intf)
1294 {
1295 	struct usbnet		*dev;
1296 	struct usb_device	*xdev;
1297 	struct net_device	*net;
1298 
1299 	dev = usb_get_intfdata(intf);
1300 	usb_set_intfdata(intf, NULL);
1301 	if (!dev)
1302 		return;
1303 
1304 	xdev = interface_to_usbdev (intf);
1305 
1306 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1307 		   intf->dev.driver->name,
1308 		   xdev->bus->bus_name, xdev->devpath,
1309 		   dev->driver_info->description);
1310 
1311 	net = dev->net;
1312 	unregister_netdev (net);
1313 
1314 	cancel_work_sync(&dev->kevent);
1315 
1316 	usb_scuttle_anchored_urbs(&dev->deferred);
1317 
1318 	if (dev->driver_info->unbind)
1319 		dev->driver_info->unbind (dev, intf);
1320 
1321 	usb_kill_urb(dev->interrupt);
1322 	usb_free_urb(dev->interrupt);
1323 
1324 	free_netdev(net);
1325 }
1326 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1327 
1328 static const struct net_device_ops usbnet_netdev_ops = {
1329 	.ndo_open		= usbnet_open,
1330 	.ndo_stop		= usbnet_stop,
1331 	.ndo_start_xmit		= usbnet_start_xmit,
1332 	.ndo_tx_timeout		= usbnet_tx_timeout,
1333 	.ndo_change_mtu		= usbnet_change_mtu,
1334 	.ndo_set_mac_address 	= eth_mac_addr,
1335 	.ndo_validate_addr	= eth_validate_addr,
1336 };
1337 
1338 /*-------------------------------------------------------------------------*/
1339 
1340 // precondition: never called in_interrupt
1341 
1342 static struct device_type wlan_type = {
1343 	.name	= "wlan",
1344 };
1345 
1346 static struct device_type wwan_type = {
1347 	.name	= "wwan",
1348 };
1349 
1350 int
1351 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1352 {
1353 	struct usbnet			*dev;
1354 	struct net_device		*net;
1355 	struct usb_host_interface	*interface;
1356 	struct driver_info		*info;
1357 	struct usb_device		*xdev;
1358 	int				status;
1359 	const char			*name;
1360 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1361 
1362 	/* usbnet already took usb runtime pm, so have to enable the feature
1363 	 * for usb interface, otherwise usb_autopm_get_interface may return
1364 	 * failure if USB_SUSPEND(RUNTIME_PM) is enabled.
1365 	 */
1366 	if (!driver->supports_autosuspend) {
1367 		driver->supports_autosuspend = 1;
1368 		pm_runtime_enable(&udev->dev);
1369 	}
1370 
1371 	name = udev->dev.driver->name;
1372 	info = (struct driver_info *) prod->driver_info;
1373 	if (!info) {
1374 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1375 		return -ENODEV;
1376 	}
1377 	xdev = interface_to_usbdev (udev);
1378 	interface = udev->cur_altsetting;
1379 
1380 	status = -ENOMEM;
1381 
1382 	// set up our own records
1383 	net = alloc_etherdev(sizeof(*dev));
1384 	if (!net)
1385 		goto out;
1386 
1387 	/* netdev_printk() needs this so do it as early as possible */
1388 	SET_NETDEV_DEV(net, &udev->dev);
1389 
1390 	dev = netdev_priv(net);
1391 	dev->udev = xdev;
1392 	dev->intf = udev;
1393 	dev->driver_info = info;
1394 	dev->driver_name = name;
1395 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1396 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1397 	skb_queue_head_init (&dev->rxq);
1398 	skb_queue_head_init (&dev->txq);
1399 	skb_queue_head_init (&dev->done);
1400 	skb_queue_head_init(&dev->rxq_pause);
1401 	dev->bh.func = usbnet_bh;
1402 	dev->bh.data = (unsigned long) dev;
1403 	INIT_WORK (&dev->kevent, kevent);
1404 	init_usb_anchor(&dev->deferred);
1405 	dev->delay.function = usbnet_bh;
1406 	dev->delay.data = (unsigned long) dev;
1407 	init_timer (&dev->delay);
1408 	mutex_init (&dev->phy_mutex);
1409 
1410 	dev->net = net;
1411 	strcpy (net->name, "usb%d");
1412 	memcpy (net->dev_addr, node_id, sizeof node_id);
1413 
1414 	/* rx and tx sides can use different message sizes;
1415 	 * bind() should set rx_urb_size in that case.
1416 	 */
1417 	dev->hard_mtu = net->mtu + net->hard_header_len;
1418 #if 0
1419 // dma_supported() is deeply broken on almost all architectures
1420 	// possible with some EHCI controllers
1421 	if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1422 		net->features |= NETIF_F_HIGHDMA;
1423 #endif
1424 
1425 	net->netdev_ops = &usbnet_netdev_ops;
1426 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1427 	net->ethtool_ops = &usbnet_ethtool_ops;
1428 
1429 	// allow device-specific bind/init procedures
1430 	// NOTE net->name still not usable ...
1431 	if (info->bind) {
1432 		status = info->bind (dev, udev);
1433 		if (status < 0)
1434 			goto out1;
1435 
1436 		// heuristic:  "usb%d" for links we know are two-host,
1437 		// else "eth%d" when there's reasonable doubt.  userspace
1438 		// can rename the link if it knows better.
1439 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1440 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1441 		     (net->dev_addr [0] & 0x02) == 0))
1442 			strcpy (net->name, "eth%d");
1443 		/* WLAN devices should always be named "wlan%d" */
1444 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1445 			strcpy(net->name, "wlan%d");
1446 		/* WWAN devices should always be named "wwan%d" */
1447 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1448 			strcpy(net->name, "wwan%d");
1449 
1450 		/* maybe the remote can't receive an Ethernet MTU */
1451 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1452 			net->mtu = dev->hard_mtu - net->hard_header_len;
1453 	} else if (!info->in || !info->out)
1454 		status = usbnet_get_endpoints (dev, udev);
1455 	else {
1456 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1457 		dev->out = usb_sndbulkpipe (xdev, info->out);
1458 		if (!(info->flags & FLAG_NO_SETINT))
1459 			status = usb_set_interface (xdev,
1460 				interface->desc.bInterfaceNumber,
1461 				interface->desc.bAlternateSetting);
1462 		else
1463 			status = 0;
1464 
1465 	}
1466 	if (status >= 0 && dev->status)
1467 		status = init_status (dev, udev);
1468 	if (status < 0)
1469 		goto out3;
1470 
1471 	if (!dev->rx_urb_size)
1472 		dev->rx_urb_size = dev->hard_mtu;
1473 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1474 
1475 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1476 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1477 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1478 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1479 
1480 	status = register_netdev (net);
1481 	if (status)
1482 		goto out4;
1483 	netif_info(dev, probe, dev->net,
1484 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1485 		   udev->dev.driver->name,
1486 		   xdev->bus->bus_name, xdev->devpath,
1487 		   dev->driver_info->description,
1488 		   net->dev_addr);
1489 
1490 	// ok, it's ready to go.
1491 	usb_set_intfdata (udev, dev);
1492 
1493 	netif_device_attach (net);
1494 
1495 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1496 		netif_carrier_off(net);
1497 
1498 	return 0;
1499 
1500 out4:
1501 	usb_free_urb(dev->interrupt);
1502 out3:
1503 	if (info->unbind)
1504 		info->unbind (dev, udev);
1505 out1:
1506 	free_netdev(net);
1507 out:
1508 	return status;
1509 }
1510 EXPORT_SYMBOL_GPL(usbnet_probe);
1511 
1512 /*-------------------------------------------------------------------------*/
1513 
1514 /*
1515  * suspend the whole driver as soon as the first interface is suspended
1516  * resume only when the last interface is resumed
1517  */
1518 
1519 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1520 {
1521 	struct usbnet		*dev = usb_get_intfdata(intf);
1522 
1523 	if (!dev->suspend_count++) {
1524 		spin_lock_irq(&dev->txq.lock);
1525 		/* don't autosuspend while transmitting */
1526 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1527 			dev->suspend_count--;
1528 			spin_unlock_irq(&dev->txq.lock);
1529 			return -EBUSY;
1530 		} else {
1531 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1532 			spin_unlock_irq(&dev->txq.lock);
1533 		}
1534 		/*
1535 		 * accelerate emptying of the rx and queues, to avoid
1536 		 * having everything error out.
1537 		 */
1538 		netif_device_detach (dev->net);
1539 		usbnet_terminate_urbs(dev);
1540 		usb_kill_urb(dev->interrupt);
1541 
1542 		/*
1543 		 * reattach so runtime management can use and
1544 		 * wake the device
1545 		 */
1546 		netif_device_attach (dev->net);
1547 	}
1548 	return 0;
1549 }
1550 EXPORT_SYMBOL_GPL(usbnet_suspend);
1551 
1552 int usbnet_resume (struct usb_interface *intf)
1553 {
1554 	struct usbnet		*dev = usb_get_intfdata(intf);
1555 	struct sk_buff          *skb;
1556 	struct urb              *res;
1557 	int                     retval;
1558 
1559 	if (!--dev->suspend_count) {
1560 		/* resume interrupt URBs */
1561 		if (dev->interrupt && test_bit(EVENT_DEV_OPEN, &dev->flags))
1562 			usb_submit_urb(dev->interrupt, GFP_NOIO);
1563 
1564 		spin_lock_irq(&dev->txq.lock);
1565 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1566 
1567 			skb = (struct sk_buff *)res->context;
1568 			retval = usb_submit_urb(res, GFP_ATOMIC);
1569 			if (retval < 0) {
1570 				dev_kfree_skb_any(skb);
1571 				usb_free_urb(res);
1572 				usb_autopm_put_interface_async(dev->intf);
1573 			} else {
1574 				dev->net->trans_start = jiffies;
1575 				__skb_queue_tail(&dev->txq, skb);
1576 			}
1577 		}
1578 
1579 		smp_mb();
1580 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1581 		spin_unlock_irq(&dev->txq.lock);
1582 
1583 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1584 			/* handle remote wakeup ASAP */
1585 			if (!dev->wait &&
1586 				netif_device_present(dev->net) &&
1587 				!timer_pending(&dev->delay) &&
1588 				!test_bit(EVENT_RX_HALT, &dev->flags))
1589 					rx_alloc_submit(dev, GFP_NOIO);
1590 
1591 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1592 				netif_tx_wake_all_queues(dev->net);
1593 			tasklet_schedule (&dev->bh);
1594 		}
1595 	}
1596 
1597 	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1598 		usb_autopm_get_interface_no_resume(intf);
1599 
1600 	return 0;
1601 }
1602 EXPORT_SYMBOL_GPL(usbnet_resume);
1603 
1604 /*
1605  * Either a subdriver implements manage_power, then it is assumed to always
1606  * be ready to be suspended or it reports the readiness to be suspended
1607  * explicitly
1608  */
1609 void usbnet_device_suggests_idle(struct usbnet *dev)
1610 {
1611 	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1612 		dev->intf->needs_remote_wakeup = 1;
1613 		usb_autopm_put_interface_async(dev->intf);
1614 	}
1615 }
1616 EXPORT_SYMBOL(usbnet_device_suggests_idle);
1617 
1618 /*-------------------------------------------------------------------------*/
1619 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1620 			     u16 value, u16 index, void *data, u16 size)
1621 {
1622 	void *buf = NULL;
1623 	int err = -ENOMEM;
1624 
1625 	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
1626 		   " value=0x%04x index=0x%04x size=%d\n",
1627 		   cmd, reqtype, value, index, size);
1628 
1629 	if (data) {
1630 		buf = kmalloc(size, GFP_KERNEL);
1631 		if (!buf)
1632 			goto out;
1633 	}
1634 
1635 	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
1636 			      cmd, reqtype, value, index, buf, size,
1637 			      USB_CTRL_GET_TIMEOUT);
1638 	if (err > 0 && err <= size)
1639 		memcpy(data, buf, err);
1640 	kfree(buf);
1641 out:
1642 	return err;
1643 }
1644 
1645 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1646 			      u16 value, u16 index, const void *data,
1647 			      u16 size)
1648 {
1649 	void *buf = NULL;
1650 	int err = -ENOMEM;
1651 
1652 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
1653 		   " value=0x%04x index=0x%04x size=%d\n",
1654 		   cmd, reqtype, value, index, size);
1655 
1656 	if (data) {
1657 		buf = kmemdup(data, size, GFP_KERNEL);
1658 		if (!buf)
1659 			goto out;
1660 	}
1661 
1662 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
1663 			      cmd, reqtype, value, index, buf, size,
1664 			      USB_CTRL_SET_TIMEOUT);
1665 	kfree(buf);
1666 
1667 out:
1668 	return err;
1669 }
1670 
1671 /*
1672  * The function can't be called inside suspend/resume callback,
1673  * otherwise deadlock will be caused.
1674  */
1675 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1676 		    u16 value, u16 index, void *data, u16 size)
1677 {
1678 	int ret;
1679 
1680 	if (usb_autopm_get_interface(dev->intf) < 0)
1681 		return -ENODEV;
1682 	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
1683 				data, size);
1684 	usb_autopm_put_interface(dev->intf);
1685 	return ret;
1686 }
1687 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
1688 
1689 /*
1690  * The function can't be called inside suspend/resume callback,
1691  * otherwise deadlock will be caused.
1692  */
1693 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1694 		     u16 value, u16 index, const void *data, u16 size)
1695 {
1696 	int ret;
1697 
1698 	if (usb_autopm_get_interface(dev->intf) < 0)
1699 		return -ENODEV;
1700 	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
1701 				 data, size);
1702 	usb_autopm_put_interface(dev->intf);
1703 	return ret;
1704 }
1705 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
1706 
1707 /*
1708  * The function can be called inside suspend/resume callback safely
1709  * and should only be called by suspend/resume callback generally.
1710  */
1711 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
1712 			  u16 value, u16 index, void *data, u16 size)
1713 {
1714 	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
1715 				 data, size);
1716 }
1717 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
1718 
1719 /*
1720  * The function can be called inside suspend/resume callback safely
1721  * and should only be called by suspend/resume callback generally.
1722  */
1723 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
1724 			  u16 value, u16 index, const void *data,
1725 			  u16 size)
1726 {
1727 	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
1728 				  data, size);
1729 }
1730 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
1731 
1732 static void usbnet_async_cmd_cb(struct urb *urb)
1733 {
1734 	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
1735 	int status = urb->status;
1736 
1737 	if (status < 0)
1738 		dev_dbg(&urb->dev->dev, "%s failed with %d",
1739 			__func__, status);
1740 
1741 	kfree(req);
1742 	usb_free_urb(urb);
1743 }
1744 
1745 /*
1746  * The caller must make sure that device can't be put into suspend
1747  * state until the control URB completes.
1748  */
1749 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
1750 			   u16 value, u16 index, const void *data, u16 size)
1751 {
1752 	struct usb_ctrlrequest *req = NULL;
1753 	struct urb *urb;
1754 	int err = -ENOMEM;
1755 	void *buf = NULL;
1756 
1757 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
1758 		   " value=0x%04x index=0x%04x size=%d\n",
1759 		   cmd, reqtype, value, index, size);
1760 
1761 	urb = usb_alloc_urb(0, GFP_ATOMIC);
1762 	if (!urb) {
1763 		netdev_err(dev->net, "Error allocating URB in"
1764 			   " %s!\n", __func__);
1765 		goto fail;
1766 	}
1767 
1768 	if (data) {
1769 		buf = kmemdup(data, size, GFP_ATOMIC);
1770 		if (!buf) {
1771 			netdev_err(dev->net, "Error allocating buffer"
1772 				   " in %s!\n", __func__);
1773 			goto fail_free;
1774 		}
1775 	}
1776 
1777 	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
1778 	if (!req) {
1779 		netdev_err(dev->net, "Failed to allocate memory for %s\n",
1780 			   __func__);
1781 		goto fail_free_buf;
1782 	}
1783 
1784 	req->bRequestType = reqtype;
1785 	req->bRequest = cmd;
1786 	req->wValue = cpu_to_le16(value);
1787 	req->wIndex = cpu_to_le16(index);
1788 	req->wLength = cpu_to_le16(size);
1789 
1790 	usb_fill_control_urb(urb, dev->udev,
1791 			     usb_sndctrlpipe(dev->udev, 0),
1792 			     (void *)req, buf, size,
1793 			     usbnet_async_cmd_cb, req);
1794 	urb->transfer_flags |= URB_FREE_BUFFER;
1795 
1796 	err = usb_submit_urb(urb, GFP_ATOMIC);
1797 	if (err < 0) {
1798 		netdev_err(dev->net, "Error submitting the control"
1799 			   " message: status=%d\n", err);
1800 		goto fail_free;
1801 	}
1802 	return 0;
1803 
1804 fail_free_buf:
1805 	kfree(buf);
1806 fail_free:
1807 	kfree(req);
1808 	usb_free_urb(urb);
1809 fail:
1810 	return err;
1811 
1812 }
1813 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
1814 /*-------------------------------------------------------------------------*/
1815 
1816 static int __init usbnet_init(void)
1817 {
1818 	/* Compiler should optimize this out. */
1819 	BUILD_BUG_ON(
1820 		FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
1821 
1822 	eth_random_addr(node_id);
1823 	return 0;
1824 }
1825 module_init(usbnet_init);
1826 
1827 static void __exit usbnet_exit(void)
1828 {
1829 }
1830 module_exit(usbnet_exit);
1831 
1832 MODULE_AUTHOR("David Brownell");
1833 MODULE_DESCRIPTION("USB network driver framework");
1834 MODULE_LICENSE("GPL");
1835