xref: /linux/drivers/net/usb/usbnet.c (revision 3ce095c16263630dde46d6051854073edaacf3d7)
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, see <http://www.gnu.org/licenses/>.
18  */
19 
20 /*
21  * This is a generic "USB networking" framework that works with several
22  * kinds of full and high speed networking devices:  host-to-host cables,
23  * smart usb peripherals, and actual Ethernet adapters.
24  *
25  * These devices usually differ in terms of control protocols (if they
26  * even have one!) and sometimes they define new framing to wrap or batch
27  * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
28  * so interface (un)binding, endpoint I/O queues, fault handling, and other
29  * issues can usefully be addressed by this framework.
30  */
31 
32 // #define	DEBUG			// error path messages, extra info
33 // #define	VERBOSE			// more; success messages
34 
35 #include <linux/module.h>
36 #include <linux/init.h>
37 #include <linux/netdevice.h>
38 #include <linux/etherdevice.h>
39 #include <linux/ctype.h>
40 #include <linux/ethtool.h>
41 #include <linux/workqueue.h>
42 #include <linux/mii.h>
43 #include <linux/usb.h>
44 #include <linux/usb/usbnet.h>
45 #include <linux/slab.h>
46 #include <linux/kernel.h>
47 #include <linux/pm_runtime.h>
48 
49 #define DRIVER_VERSION		"22-Aug-2005"
50 
51 
52 /*-------------------------------------------------------------------------*/
53 
54 /*
55  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
56  * Several dozen bytes of IPv4 data can fit in two such transactions.
57  * One maximum size Ethernet packet takes twenty four of them.
58  * For high speed, each frame comfortably fits almost 36 max size
59  * Ethernet packets (so queues should be bigger).
60  *
61  * The goal is to let the USB host controller be busy for 5msec or
62  * more before an irq is required, under load.  Jumbograms change
63  * the equation.
64  */
65 #define	MAX_QUEUE_MEMORY	(60 * 1518)
66 #define	RX_QLEN(dev)		((dev)->rx_qlen)
67 #define	TX_QLEN(dev)		((dev)->tx_qlen)
68 
69 // reawaken network queue this soon after stopping; else watchdog barks
70 #define TX_TIMEOUT_JIFFIES	(5*HZ)
71 
72 /* throttle rx/tx briefly after some faults, so hub_wq might disconnect()
73  * us (it polls at HZ/4 usually) before we report too many false errors.
74  */
75 #define THROTTLE_JIFFIES	(HZ/8)
76 
77 // between wakeups
78 #define UNLINK_TIMEOUT_MS	3
79 
80 /*-------------------------------------------------------------------------*/
81 
82 // randomly generated ethernet address
83 static u8	node_id [ETH_ALEN];
84 
85 static const char driver_name [] = "usbnet";
86 
87 /* use ethtool to change the level for any given device */
88 static int msg_level = -1;
89 module_param (msg_level, int, 0);
90 MODULE_PARM_DESC (msg_level, "Override default message level");
91 
92 /*-------------------------------------------------------------------------*/
93 
94 /* handles CDC Ethernet and many other network "bulk data" interfaces */
95 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
96 {
97 	int				tmp;
98 	struct usb_host_interface	*alt = NULL;
99 	struct usb_host_endpoint	*in = NULL, *out = NULL;
100 	struct usb_host_endpoint	*status = NULL;
101 
102 	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
103 		unsigned	ep;
104 
105 		in = out = status = NULL;
106 		alt = intf->altsetting + tmp;
107 
108 		/* take the first altsetting with in-bulk + out-bulk;
109 		 * remember any status endpoint, just in case;
110 		 * ignore other endpoints and altsettings.
111 		 */
112 		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
113 			struct usb_host_endpoint	*e;
114 			int				intr = 0;
115 
116 			e = alt->endpoint + ep;
117 			switch (e->desc.bmAttributes) {
118 			case USB_ENDPOINT_XFER_INT:
119 				if (!usb_endpoint_dir_in(&e->desc))
120 					continue;
121 				intr = 1;
122 				/* FALLTHROUGH */
123 			case USB_ENDPOINT_XFER_BULK:
124 				break;
125 			default:
126 				continue;
127 			}
128 			if (usb_endpoint_dir_in(&e->desc)) {
129 				if (!intr && !in)
130 					in = e;
131 				else if (intr && !status)
132 					status = e;
133 			} else {
134 				if (!out)
135 					out = e;
136 			}
137 		}
138 		if (in && out)
139 			break;
140 	}
141 	if (!alt || !in || !out)
142 		return -EINVAL;
143 
144 	if (alt->desc.bAlternateSetting != 0 ||
145 	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
146 		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
147 				alt->desc.bAlternateSetting);
148 		if (tmp < 0)
149 			return tmp;
150 	}
151 
152 	dev->in = usb_rcvbulkpipe (dev->udev,
153 			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
154 	dev->out = usb_sndbulkpipe (dev->udev,
155 			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
156 	dev->status = status;
157 	return 0;
158 }
159 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
160 
161 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
162 {
163 	int 		tmp = -1, ret;
164 	unsigned char	buf [13];
165 
166 	ret = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
167 	if (ret == 12)
168 		tmp = hex2bin(dev->net->dev_addr, buf, 6);
169 	if (tmp < 0) {
170 		dev_dbg(&dev->udev->dev,
171 			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
172 		if (ret >= 0)
173 			ret = -EINVAL;
174 		return ret;
175 	}
176 	return 0;
177 }
178 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
179 
180 static void intr_complete (struct urb *urb)
181 {
182 	struct usbnet	*dev = urb->context;
183 	int		status = urb->status;
184 
185 	switch (status) {
186 	/* success */
187 	case 0:
188 		dev->driver_info->status(dev, urb);
189 		break;
190 
191 	/* software-driven interface shutdown */
192 	case -ENOENT:		/* urb killed */
193 	case -ESHUTDOWN:	/* hardware gone */
194 		netif_dbg(dev, ifdown, dev->net,
195 			  "intr shutdown, code %d\n", status);
196 		return;
197 
198 	/* NOTE:  not throttling like RX/TX, since this endpoint
199 	 * already polls infrequently
200 	 */
201 	default:
202 		netdev_dbg(dev->net, "intr status %d\n", status);
203 		break;
204 	}
205 
206 	status = usb_submit_urb (urb, GFP_ATOMIC);
207 	if (status != 0)
208 		netif_err(dev, timer, dev->net,
209 			  "intr resubmit --> %d\n", status);
210 }
211 
212 static int init_status (struct usbnet *dev, struct usb_interface *intf)
213 {
214 	char		*buf = NULL;
215 	unsigned	pipe = 0;
216 	unsigned	maxp;
217 	unsigned	period;
218 
219 	if (!dev->driver_info->status)
220 		return 0;
221 
222 	pipe = usb_rcvintpipe (dev->udev,
223 			dev->status->desc.bEndpointAddress
224 				& USB_ENDPOINT_NUMBER_MASK);
225 	maxp = usb_maxpacket (dev->udev, pipe, 0);
226 
227 	/* avoid 1 msec chatter:  min 8 msec poll rate */
228 	period = max ((int) dev->status->desc.bInterval,
229 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
230 
231 	buf = kmalloc (maxp, GFP_KERNEL);
232 	if (buf) {
233 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
234 		if (!dev->interrupt) {
235 			kfree (buf);
236 			return -ENOMEM;
237 		} else {
238 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
239 				buf, maxp, intr_complete, dev, period);
240 			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
241 			dev_dbg(&intf->dev,
242 				"status ep%din, %d bytes period %d\n",
243 				usb_pipeendpoint(pipe), maxp, period);
244 		}
245 	}
246 	return 0;
247 }
248 
249 /* Submit the interrupt URB if not previously submitted, increasing refcount */
250 int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
251 {
252 	int ret = 0;
253 
254 	WARN_ON_ONCE(dev->interrupt == NULL);
255 	if (dev->interrupt) {
256 		mutex_lock(&dev->interrupt_mutex);
257 
258 		if (++dev->interrupt_count == 1)
259 			ret = usb_submit_urb(dev->interrupt, mem_flags);
260 
261 		dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
262 			dev->interrupt_count);
263 		mutex_unlock(&dev->interrupt_mutex);
264 	}
265 	return ret;
266 }
267 EXPORT_SYMBOL_GPL(usbnet_status_start);
268 
269 /* For resume; submit interrupt URB if previously submitted */
270 static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
271 {
272 	int ret = 0;
273 
274 	mutex_lock(&dev->interrupt_mutex);
275 	if (dev->interrupt_count) {
276 		ret = usb_submit_urb(dev->interrupt, mem_flags);
277 		dev_dbg(&dev->udev->dev,
278 			"submitted interrupt URB for resume\n");
279 	}
280 	mutex_unlock(&dev->interrupt_mutex);
281 	return ret;
282 }
283 
284 /* Kill the interrupt URB if all submitters want it killed */
285 void usbnet_status_stop(struct usbnet *dev)
286 {
287 	if (dev->interrupt) {
288 		mutex_lock(&dev->interrupt_mutex);
289 		WARN_ON(dev->interrupt_count == 0);
290 
291 		if (dev->interrupt_count && --dev->interrupt_count == 0)
292 			usb_kill_urb(dev->interrupt);
293 
294 		dev_dbg(&dev->udev->dev,
295 			"decremented interrupt URB count to %d\n",
296 			dev->interrupt_count);
297 		mutex_unlock(&dev->interrupt_mutex);
298 	}
299 }
300 EXPORT_SYMBOL_GPL(usbnet_status_stop);
301 
302 /* For suspend; always kill interrupt URB */
303 static void __usbnet_status_stop_force(struct usbnet *dev)
304 {
305 	if (dev->interrupt) {
306 		mutex_lock(&dev->interrupt_mutex);
307 		usb_kill_urb(dev->interrupt);
308 		dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
309 		mutex_unlock(&dev->interrupt_mutex);
310 	}
311 }
312 
313 /* Passes this packet up the stack, updating its accounting.
314  * Some link protocols batch packets, so their rx_fixup paths
315  * can return clones as well as just modify the original skb.
316  */
317 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
318 {
319 	int	status;
320 
321 	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
322 		skb_queue_tail(&dev->rxq_pause, skb);
323 		return;
324 	}
325 
326 	skb->protocol = eth_type_trans (skb, dev->net);
327 	dev->net->stats.rx_packets++;
328 	dev->net->stats.rx_bytes += skb->len;
329 
330 	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
331 		  skb->len + sizeof (struct ethhdr), skb->protocol);
332 	memset (skb->cb, 0, sizeof (struct skb_data));
333 
334 	if (skb_defer_rx_timestamp(skb))
335 		return;
336 
337 	status = netif_rx (skb);
338 	if (status != NET_RX_SUCCESS)
339 		netif_dbg(dev, rx_err, dev->net,
340 			  "netif_rx status %d\n", status);
341 }
342 EXPORT_SYMBOL_GPL(usbnet_skb_return);
343 
344 /* must be called if hard_mtu or rx_urb_size changed */
345 void usbnet_update_max_qlen(struct usbnet *dev)
346 {
347 	enum usb_device_speed speed = dev->udev->speed;
348 
349 	switch (speed) {
350 	case USB_SPEED_HIGH:
351 		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
352 		dev->tx_qlen = MAX_QUEUE_MEMORY / dev->hard_mtu;
353 		break;
354 	case USB_SPEED_SUPER:
355 		/*
356 		 * Not take default 5ms qlen for super speed HC to
357 		 * save memory, and iperf tests show 2.5ms qlen can
358 		 * work well
359 		 */
360 		dev->rx_qlen = 5 * MAX_QUEUE_MEMORY / dev->rx_urb_size;
361 		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
362 		break;
363 	default:
364 		dev->rx_qlen = dev->tx_qlen = 4;
365 	}
366 }
367 EXPORT_SYMBOL_GPL(usbnet_update_max_qlen);
368 
369 
370 /*-------------------------------------------------------------------------
371  *
372  * Network Device Driver (peer link to "Host Device", from USB host)
373  *
374  *-------------------------------------------------------------------------*/
375 
376 int usbnet_change_mtu (struct net_device *net, int new_mtu)
377 {
378 	struct usbnet	*dev = netdev_priv(net);
379 	int		ll_mtu = new_mtu + net->hard_header_len;
380 	int		old_hard_mtu = dev->hard_mtu;
381 	int		old_rx_urb_size = dev->rx_urb_size;
382 
383 	if (new_mtu <= 0)
384 		return -EINVAL;
385 	// no second zero-length packet read wanted after mtu-sized packets
386 	if ((ll_mtu % dev->maxpacket) == 0)
387 		return -EDOM;
388 	net->mtu = new_mtu;
389 
390 	dev->hard_mtu = net->mtu + net->hard_header_len;
391 	if (dev->rx_urb_size == old_hard_mtu) {
392 		dev->rx_urb_size = dev->hard_mtu;
393 		if (dev->rx_urb_size > old_rx_urb_size)
394 			usbnet_unlink_rx_urbs(dev);
395 	}
396 
397 	/* max qlen depend on hard_mtu and rx_urb_size */
398 	usbnet_update_max_qlen(dev);
399 
400 	return 0;
401 }
402 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
403 
404 /* The caller must hold list->lock */
405 static void __usbnet_queue_skb(struct sk_buff_head *list,
406 			struct sk_buff *newsk, enum skb_state state)
407 {
408 	struct skb_data *entry = (struct skb_data *) newsk->cb;
409 
410 	__skb_queue_tail(list, newsk);
411 	entry->state = state;
412 }
413 
414 /*-------------------------------------------------------------------------*/
415 
416 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
417  * completion callbacks.  2.5 should have fixed those bugs...
418  */
419 
420 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
421 		struct sk_buff_head *list, enum skb_state state)
422 {
423 	unsigned long		flags;
424 	enum skb_state 		old_state;
425 	struct skb_data *entry = (struct skb_data *) skb->cb;
426 
427 	spin_lock_irqsave(&list->lock, flags);
428 	old_state = entry->state;
429 	entry->state = state;
430 	__skb_unlink(skb, list);
431 	spin_unlock(&list->lock);
432 	spin_lock(&dev->done.lock);
433 	__skb_queue_tail(&dev->done, skb);
434 	if (dev->done.qlen == 1)
435 		tasklet_schedule(&dev->bh);
436 	spin_unlock_irqrestore(&dev->done.lock, flags);
437 	return old_state;
438 }
439 
440 /* some work can't be done in tasklets, so we use keventd
441  *
442  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
443  * but tasklet_schedule() doesn't.  hope the failure is rare.
444  */
445 void usbnet_defer_kevent (struct usbnet *dev, int work)
446 {
447 	set_bit (work, &dev->flags);
448 	if (!schedule_work (&dev->kevent)) {
449 		if (net_ratelimit())
450 			netdev_err(dev->net, "kevent %d may have been dropped\n", work);
451 	} else {
452 		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
453 	}
454 }
455 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
456 
457 /*-------------------------------------------------------------------------*/
458 
459 static void rx_complete (struct urb *urb);
460 
461 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
462 {
463 	struct sk_buff		*skb;
464 	struct skb_data		*entry;
465 	int			retval = 0;
466 	unsigned long		lockflags;
467 	size_t			size = dev->rx_urb_size;
468 
469 	/* prevent rx skb allocation when error ratio is high */
470 	if (test_bit(EVENT_RX_KILL, &dev->flags)) {
471 		usb_free_urb(urb);
472 		return -ENOLINK;
473 	}
474 
475 	skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
476 	if (!skb) {
477 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
478 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
479 		usb_free_urb (urb);
480 		return -ENOMEM;
481 	}
482 
483 	entry = (struct skb_data *) skb->cb;
484 	entry->urb = urb;
485 	entry->dev = dev;
486 	entry->length = 0;
487 
488 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
489 		skb->data, size, rx_complete, skb);
490 
491 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
492 
493 	if (netif_running (dev->net) &&
494 	    netif_device_present (dev->net) &&
495 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
496 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
497 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
498 		case -EPIPE:
499 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
500 			break;
501 		case -ENOMEM:
502 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
503 			break;
504 		case -ENODEV:
505 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
506 			netif_device_detach (dev->net);
507 			break;
508 		case -EHOSTUNREACH:
509 			retval = -ENOLINK;
510 			break;
511 		default:
512 			netif_dbg(dev, rx_err, dev->net,
513 				  "rx submit, %d\n", retval);
514 			tasklet_schedule (&dev->bh);
515 			break;
516 		case 0:
517 			__usbnet_queue_skb(&dev->rxq, skb, rx_start);
518 		}
519 	} else {
520 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
521 		retval = -ENOLINK;
522 	}
523 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
524 	if (retval) {
525 		dev_kfree_skb_any (skb);
526 		usb_free_urb (urb);
527 	}
528 	return retval;
529 }
530 
531 
532 /*-------------------------------------------------------------------------*/
533 
534 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
535 {
536 	if (dev->driver_info->rx_fixup &&
537 	    !dev->driver_info->rx_fixup (dev, skb)) {
538 		/* With RX_ASSEMBLE, rx_fixup() must update counters */
539 		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
540 			dev->net->stats.rx_errors++;
541 		goto done;
542 	}
543 	// else network stack removes extra byte if we forced a short packet
544 
545 	/* all data was already cloned from skb inside the driver */
546 	if (dev->driver_info->flags & FLAG_MULTI_PACKET)
547 		goto done;
548 
549 	if (skb->len < ETH_HLEN) {
550 		dev->net->stats.rx_errors++;
551 		dev->net->stats.rx_length_errors++;
552 		netif_dbg(dev, rx_err, dev->net, "rx length %d\n", skb->len);
553 	} else {
554 		usbnet_skb_return(dev, skb);
555 		return;
556 	}
557 
558 done:
559 	skb_queue_tail(&dev->done, skb);
560 }
561 
562 /*-------------------------------------------------------------------------*/
563 
564 static void rx_complete (struct urb *urb)
565 {
566 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
567 	struct skb_data		*entry = (struct skb_data *) skb->cb;
568 	struct usbnet		*dev = entry->dev;
569 	int			urb_status = urb->status;
570 	enum skb_state		state;
571 
572 	skb_put (skb, urb->actual_length);
573 	state = rx_done;
574 	entry->urb = NULL;
575 
576 	switch (urb_status) {
577 	/* success */
578 	case 0:
579 		break;
580 
581 	/* stalls need manual reset. this is rare ... except that
582 	 * when going through USB 2.0 TTs, unplug appears this way.
583 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
584 	 * storm, recovering as needed.
585 	 */
586 	case -EPIPE:
587 		dev->net->stats.rx_errors++;
588 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
589 		// FALLTHROUGH
590 
591 	/* software-driven interface shutdown */
592 	case -ECONNRESET:		/* async unlink */
593 	case -ESHUTDOWN:		/* hardware gone */
594 		netif_dbg(dev, ifdown, dev->net,
595 			  "rx shutdown, code %d\n", urb_status);
596 		goto block;
597 
598 	/* we get controller i/o faults during hub_wq disconnect() delays.
599 	 * throttle down resubmits, to avoid log floods; just temporarily,
600 	 * so we still recover when the fault isn't a hub_wq delay.
601 	 */
602 	case -EPROTO:
603 	case -ETIME:
604 	case -EILSEQ:
605 		dev->net->stats.rx_errors++;
606 		if (!timer_pending (&dev->delay)) {
607 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
608 			netif_dbg(dev, link, dev->net,
609 				  "rx throttle %d\n", urb_status);
610 		}
611 block:
612 		state = rx_cleanup;
613 		entry->urb = urb;
614 		urb = NULL;
615 		break;
616 
617 	/* data overrun ... flush fifo? */
618 	case -EOVERFLOW:
619 		dev->net->stats.rx_over_errors++;
620 		// FALLTHROUGH
621 
622 	default:
623 		state = rx_cleanup;
624 		dev->net->stats.rx_errors++;
625 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
626 		break;
627 	}
628 
629 	/* stop rx if packet error rate is high */
630 	if (++dev->pkt_cnt > 30) {
631 		dev->pkt_cnt = 0;
632 		dev->pkt_err = 0;
633 	} else {
634 		if (state == rx_cleanup)
635 			dev->pkt_err++;
636 		if (dev->pkt_err > 20)
637 			set_bit(EVENT_RX_KILL, &dev->flags);
638 	}
639 
640 	state = defer_bh(dev, skb, &dev->rxq, state);
641 
642 	if (urb) {
643 		if (netif_running (dev->net) &&
644 		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
645 		    state != unlink_start) {
646 			rx_submit (dev, urb, GFP_ATOMIC);
647 			usb_mark_last_busy(dev->udev);
648 			return;
649 		}
650 		usb_free_urb (urb);
651 	}
652 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
653 }
654 
655 /*-------------------------------------------------------------------------*/
656 void usbnet_pause_rx(struct usbnet *dev)
657 {
658 	set_bit(EVENT_RX_PAUSED, &dev->flags);
659 
660 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
661 }
662 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
663 
664 void usbnet_resume_rx(struct usbnet *dev)
665 {
666 	struct sk_buff *skb;
667 	int num = 0;
668 
669 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
670 
671 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
672 		usbnet_skb_return(dev, skb);
673 		num++;
674 	}
675 
676 	tasklet_schedule(&dev->bh);
677 
678 	netif_dbg(dev, rx_status, dev->net,
679 		  "paused rx queue disabled, %d skbs requeued\n", num);
680 }
681 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
682 
683 void usbnet_purge_paused_rxq(struct usbnet *dev)
684 {
685 	skb_queue_purge(&dev->rxq_pause);
686 }
687 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
688 
689 /*-------------------------------------------------------------------------*/
690 
691 // unlink pending rx/tx; completion handlers do all other cleanup
692 
693 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
694 {
695 	unsigned long		flags;
696 	struct sk_buff		*skb;
697 	int			count = 0;
698 
699 	spin_lock_irqsave (&q->lock, flags);
700 	while (!skb_queue_empty(q)) {
701 		struct skb_data		*entry;
702 		struct urb		*urb;
703 		int			retval;
704 
705 		skb_queue_walk(q, skb) {
706 			entry = (struct skb_data *) skb->cb;
707 			if (entry->state != unlink_start)
708 				goto found;
709 		}
710 		break;
711 found:
712 		entry->state = unlink_start;
713 		urb = entry->urb;
714 
715 		/*
716 		 * Get reference count of the URB to avoid it to be
717 		 * freed during usb_unlink_urb, which may trigger
718 		 * use-after-free problem inside usb_unlink_urb since
719 		 * usb_unlink_urb is always racing with .complete
720 		 * handler(include defer_bh).
721 		 */
722 		usb_get_urb(urb);
723 		spin_unlock_irqrestore(&q->lock, flags);
724 		// during some PM-driven resume scenarios,
725 		// these (async) unlinks complete immediately
726 		retval = usb_unlink_urb (urb);
727 		if (retval != -EINPROGRESS && retval != 0)
728 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
729 		else
730 			count++;
731 		usb_put_urb(urb);
732 		spin_lock_irqsave(&q->lock, flags);
733 	}
734 	spin_unlock_irqrestore (&q->lock, flags);
735 	return count;
736 }
737 
738 // Flush all pending rx urbs
739 // minidrivers may need to do this when the MTU changes
740 
741 void usbnet_unlink_rx_urbs(struct usbnet *dev)
742 {
743 	if (netif_running(dev->net)) {
744 		(void) unlink_urbs (dev, &dev->rxq);
745 		tasklet_schedule(&dev->bh);
746 	}
747 }
748 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
749 
750 /*-------------------------------------------------------------------------*/
751 
752 // precondition: never called in_interrupt
753 static void usbnet_terminate_urbs(struct usbnet *dev)
754 {
755 	DECLARE_WAITQUEUE(wait, current);
756 	int temp;
757 
758 	/* ensure there are no more active urbs */
759 	add_wait_queue(&dev->wait, &wait);
760 	set_current_state(TASK_UNINTERRUPTIBLE);
761 	temp = unlink_urbs(dev, &dev->txq) +
762 		unlink_urbs(dev, &dev->rxq);
763 
764 	/* maybe wait for deletions to finish. */
765 	while (!skb_queue_empty(&dev->rxq)
766 		&& !skb_queue_empty(&dev->txq)
767 		&& !skb_queue_empty(&dev->done)) {
768 			schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
769 			set_current_state(TASK_UNINTERRUPTIBLE);
770 			netif_dbg(dev, ifdown, dev->net,
771 				  "waited for %d urb completions\n", temp);
772 	}
773 	set_current_state(TASK_RUNNING);
774 	remove_wait_queue(&dev->wait, &wait);
775 }
776 
777 int usbnet_stop (struct net_device *net)
778 {
779 	struct usbnet		*dev = netdev_priv(net);
780 	struct driver_info	*info = dev->driver_info;
781 	int			retval, pm;
782 
783 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
784 	netif_stop_queue (net);
785 
786 	netif_info(dev, ifdown, dev->net,
787 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
788 		   net->stats.rx_packets, net->stats.tx_packets,
789 		   net->stats.rx_errors, net->stats.tx_errors);
790 
791 	/* to not race resume */
792 	pm = usb_autopm_get_interface(dev->intf);
793 	/* allow minidriver to stop correctly (wireless devices to turn off
794 	 * radio etc) */
795 	if (info->stop) {
796 		retval = info->stop(dev);
797 		if (retval < 0)
798 			netif_info(dev, ifdown, dev->net,
799 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
800 				   retval,
801 				   dev->udev->bus->bus_name, dev->udev->devpath,
802 				   info->description);
803 	}
804 
805 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
806 		usbnet_terminate_urbs(dev);
807 
808 	usbnet_status_stop(dev);
809 
810 	usbnet_purge_paused_rxq(dev);
811 
812 	/* deferred work (task, timer, softirq) must also stop.
813 	 * can't flush_scheduled_work() until we drop rtnl (later),
814 	 * else workers could deadlock; so make workers a NOP.
815 	 */
816 	dev->flags = 0;
817 	del_timer_sync (&dev->delay);
818 	tasklet_kill (&dev->bh);
819 	if (!pm)
820 		usb_autopm_put_interface(dev->intf);
821 
822 	if (info->manage_power &&
823 	    !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags))
824 		info->manage_power(dev, 0);
825 	else
826 		usb_autopm_put_interface(dev->intf);
827 
828 	return 0;
829 }
830 EXPORT_SYMBOL_GPL(usbnet_stop);
831 
832 /*-------------------------------------------------------------------------*/
833 
834 // posts reads, and enables write queuing
835 
836 // precondition: never called in_interrupt
837 
838 int usbnet_open (struct net_device *net)
839 {
840 	struct usbnet		*dev = netdev_priv(net);
841 	int			retval;
842 	struct driver_info	*info = dev->driver_info;
843 
844 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
845 		netif_info(dev, ifup, dev->net,
846 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
847 			   retval,
848 			   dev->udev->bus->bus_name,
849 			   dev->udev->devpath,
850 			   info->description);
851 		goto done_nopm;
852 	}
853 
854 	// put into "known safe" state
855 	if (info->reset && (retval = info->reset (dev)) < 0) {
856 		netif_info(dev, ifup, dev->net,
857 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
858 			   retval,
859 			   dev->udev->bus->bus_name,
860 			   dev->udev->devpath,
861 			   info->description);
862 		goto done;
863 	}
864 
865 	/* hard_mtu or rx_urb_size may change in reset() */
866 	usbnet_update_max_qlen(dev);
867 
868 	// insist peer be connected
869 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
870 		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
871 		goto done;
872 	}
873 
874 	/* start any status interrupt transfer */
875 	if (dev->interrupt) {
876 		retval = usbnet_status_start(dev, GFP_KERNEL);
877 		if (retval < 0) {
878 			netif_err(dev, ifup, dev->net,
879 				  "intr submit %d\n", retval);
880 			goto done;
881 		}
882 	}
883 
884 	set_bit(EVENT_DEV_OPEN, &dev->flags);
885 	netif_start_queue (net);
886 	netif_info(dev, ifup, dev->net,
887 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
888 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
889 		   dev->net->mtu,
890 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
891 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
892 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
893 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
894 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
895 		   "simple");
896 
897 	/* reset rx error state */
898 	dev->pkt_cnt = 0;
899 	dev->pkt_err = 0;
900 	clear_bit(EVENT_RX_KILL, &dev->flags);
901 
902 	// delay posting reads until we're fully open
903 	tasklet_schedule (&dev->bh);
904 	if (info->manage_power) {
905 		retval = info->manage_power(dev, 1);
906 		if (retval < 0) {
907 			retval = 0;
908 			set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
909 		} else {
910 			usb_autopm_put_interface(dev->intf);
911 		}
912 	}
913 	return retval;
914 done:
915 	usb_autopm_put_interface(dev->intf);
916 done_nopm:
917 	return retval;
918 }
919 EXPORT_SYMBOL_GPL(usbnet_open);
920 
921 /*-------------------------------------------------------------------------*/
922 
923 /* ethtool methods; minidrivers may need to add some more, but
924  * they'll probably want to use this base set.
925  */
926 
927 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
928 {
929 	struct usbnet *dev = netdev_priv(net);
930 
931 	if (!dev->mii.mdio_read)
932 		return -EOPNOTSUPP;
933 
934 	return mii_ethtool_gset(&dev->mii, cmd);
935 }
936 EXPORT_SYMBOL_GPL(usbnet_get_settings);
937 
938 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
939 {
940 	struct usbnet *dev = netdev_priv(net);
941 	int retval;
942 
943 	if (!dev->mii.mdio_write)
944 		return -EOPNOTSUPP;
945 
946 	retval = mii_ethtool_sset(&dev->mii, cmd);
947 
948 	/* link speed/duplex might have changed */
949 	if (dev->driver_info->link_reset)
950 		dev->driver_info->link_reset(dev);
951 
952 	/* hard_mtu or rx_urb_size may change in link_reset() */
953 	usbnet_update_max_qlen(dev);
954 
955 	return retval;
956 
957 }
958 EXPORT_SYMBOL_GPL(usbnet_set_settings);
959 
960 u32 usbnet_get_link (struct net_device *net)
961 {
962 	struct usbnet *dev = netdev_priv(net);
963 
964 	/* If a check_connect is defined, return its result */
965 	if (dev->driver_info->check_connect)
966 		return dev->driver_info->check_connect (dev) == 0;
967 
968 	/* if the device has mii operations, use those */
969 	if (dev->mii.mdio_read)
970 		return mii_link_ok(&dev->mii);
971 
972 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
973 	return ethtool_op_get_link(net);
974 }
975 EXPORT_SYMBOL_GPL(usbnet_get_link);
976 
977 int usbnet_nway_reset(struct net_device *net)
978 {
979 	struct usbnet *dev = netdev_priv(net);
980 
981 	if (!dev->mii.mdio_write)
982 		return -EOPNOTSUPP;
983 
984 	return mii_nway_restart(&dev->mii);
985 }
986 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
987 
988 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
989 {
990 	struct usbnet *dev = netdev_priv(net);
991 
992 	strlcpy (info->driver, dev->driver_name, sizeof info->driver);
993 	strlcpy (info->version, DRIVER_VERSION, sizeof info->version);
994 	strlcpy (info->fw_version, dev->driver_info->description,
995 		sizeof info->fw_version);
996 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
997 }
998 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
999 
1000 u32 usbnet_get_msglevel (struct net_device *net)
1001 {
1002 	struct usbnet *dev = netdev_priv(net);
1003 
1004 	return dev->msg_enable;
1005 }
1006 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
1007 
1008 void usbnet_set_msglevel (struct net_device *net, u32 level)
1009 {
1010 	struct usbnet *dev = netdev_priv(net);
1011 
1012 	dev->msg_enable = level;
1013 }
1014 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
1015 
1016 /* drivers may override default ethtool_ops in their bind() routine */
1017 static const struct ethtool_ops usbnet_ethtool_ops = {
1018 	.get_settings		= usbnet_get_settings,
1019 	.set_settings		= usbnet_set_settings,
1020 	.get_link		= usbnet_get_link,
1021 	.nway_reset		= usbnet_nway_reset,
1022 	.get_drvinfo		= usbnet_get_drvinfo,
1023 	.get_msglevel		= usbnet_get_msglevel,
1024 	.set_msglevel		= usbnet_set_msglevel,
1025 	.get_ts_info		= ethtool_op_get_ts_info,
1026 };
1027 
1028 /*-------------------------------------------------------------------------*/
1029 
1030 static void __handle_link_change(struct usbnet *dev)
1031 {
1032 	if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
1033 		return;
1034 
1035 	if (!netif_carrier_ok(dev->net)) {
1036 		/* kill URBs for reading packets to save bus bandwidth */
1037 		unlink_urbs(dev, &dev->rxq);
1038 
1039 		/*
1040 		 * tx_timeout will unlink URBs for sending packets and
1041 		 * tx queue is stopped by netcore after link becomes off
1042 		 */
1043 	} else {
1044 		/* submitting URBs for reading packets */
1045 		tasklet_schedule(&dev->bh);
1046 	}
1047 
1048 	/* hard_mtu or rx_urb_size may change during link change */
1049 	usbnet_update_max_qlen(dev);
1050 
1051 	clear_bit(EVENT_LINK_CHANGE, &dev->flags);
1052 }
1053 
1054 static void usbnet_set_rx_mode(struct net_device *net)
1055 {
1056 	struct usbnet		*dev = netdev_priv(net);
1057 
1058 	usbnet_defer_kevent(dev, EVENT_SET_RX_MODE);
1059 }
1060 
1061 static void __handle_set_rx_mode(struct usbnet *dev)
1062 {
1063 	if (dev->driver_info->set_rx_mode)
1064 		(dev->driver_info->set_rx_mode)(dev);
1065 
1066 	clear_bit(EVENT_SET_RX_MODE, &dev->flags);
1067 }
1068 
1069 /* work that cannot be done in interrupt context uses keventd.
1070  *
1071  * NOTE:  with 2.5 we could do more of this using completion callbacks,
1072  * especially now that control transfers can be queued.
1073  */
1074 static void
1075 usbnet_deferred_kevent (struct work_struct *work)
1076 {
1077 	struct usbnet		*dev =
1078 		container_of(work, struct usbnet, kevent);
1079 	int			status;
1080 
1081 	/* usb_clear_halt() needs a thread context */
1082 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
1083 		unlink_urbs (dev, &dev->txq);
1084 		status = usb_autopm_get_interface(dev->intf);
1085 		if (status < 0)
1086 			goto fail_pipe;
1087 		status = usb_clear_halt (dev->udev, dev->out);
1088 		usb_autopm_put_interface(dev->intf);
1089 		if (status < 0 &&
1090 		    status != -EPIPE &&
1091 		    status != -ESHUTDOWN) {
1092 			if (netif_msg_tx_err (dev))
1093 fail_pipe:
1094 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
1095 					   status);
1096 		} else {
1097 			clear_bit (EVENT_TX_HALT, &dev->flags);
1098 			if (status != -ESHUTDOWN)
1099 				netif_wake_queue (dev->net);
1100 		}
1101 	}
1102 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
1103 		unlink_urbs (dev, &dev->rxq);
1104 		status = usb_autopm_get_interface(dev->intf);
1105 		if (status < 0)
1106 			goto fail_halt;
1107 		status = usb_clear_halt (dev->udev, dev->in);
1108 		usb_autopm_put_interface(dev->intf);
1109 		if (status < 0 &&
1110 		    status != -EPIPE &&
1111 		    status != -ESHUTDOWN) {
1112 			if (netif_msg_rx_err (dev))
1113 fail_halt:
1114 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
1115 					   status);
1116 		} else {
1117 			clear_bit (EVENT_RX_HALT, &dev->flags);
1118 			tasklet_schedule (&dev->bh);
1119 		}
1120 	}
1121 
1122 	/* tasklet could resubmit itself forever if memory is tight */
1123 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
1124 		struct urb	*urb = NULL;
1125 		int resched = 1;
1126 
1127 		if (netif_running (dev->net))
1128 			urb = usb_alloc_urb (0, GFP_KERNEL);
1129 		else
1130 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1131 		if (urb != NULL) {
1132 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1133 			status = usb_autopm_get_interface(dev->intf);
1134 			if (status < 0) {
1135 				usb_free_urb(urb);
1136 				goto fail_lowmem;
1137 			}
1138 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
1139 				resched = 0;
1140 			usb_autopm_put_interface(dev->intf);
1141 fail_lowmem:
1142 			if (resched)
1143 				tasklet_schedule (&dev->bh);
1144 		}
1145 	}
1146 
1147 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
1148 		struct driver_info	*info = dev->driver_info;
1149 		int			retval = 0;
1150 
1151 		clear_bit (EVENT_LINK_RESET, &dev->flags);
1152 		status = usb_autopm_get_interface(dev->intf);
1153 		if (status < 0)
1154 			goto skip_reset;
1155 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1156 			usb_autopm_put_interface(dev->intf);
1157 skip_reset:
1158 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1159 				    retval,
1160 				    dev->udev->bus->bus_name,
1161 				    dev->udev->devpath,
1162 				    info->description);
1163 		} else {
1164 			usb_autopm_put_interface(dev->intf);
1165 		}
1166 
1167 		/* handle link change from link resetting */
1168 		__handle_link_change(dev);
1169 	}
1170 
1171 	if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
1172 		__handle_link_change(dev);
1173 
1174 	if (test_bit (EVENT_SET_RX_MODE, &dev->flags))
1175 		__handle_set_rx_mode(dev);
1176 
1177 
1178 	if (dev->flags)
1179 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1180 }
1181 
1182 /*-------------------------------------------------------------------------*/
1183 
1184 static void tx_complete (struct urb *urb)
1185 {
1186 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1187 	struct skb_data		*entry = (struct skb_data *) skb->cb;
1188 	struct usbnet		*dev = entry->dev;
1189 
1190 	if (urb->status == 0) {
1191 		dev->net->stats.tx_packets += entry->packets;
1192 		dev->net->stats.tx_bytes += entry->length;
1193 	} else {
1194 		dev->net->stats.tx_errors++;
1195 
1196 		switch (urb->status) {
1197 		case -EPIPE:
1198 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1199 			break;
1200 
1201 		/* software-driven interface shutdown */
1202 		case -ECONNRESET:		// async unlink
1203 		case -ESHUTDOWN:		// hardware gone
1204 			break;
1205 
1206 		/* like rx, tx gets controller i/o faults during hub_wq
1207 		 * delays and so it uses the same throttling mechanism.
1208 		 */
1209 		case -EPROTO:
1210 		case -ETIME:
1211 		case -EILSEQ:
1212 			usb_mark_last_busy(dev->udev);
1213 			if (!timer_pending (&dev->delay)) {
1214 				mod_timer (&dev->delay,
1215 					jiffies + THROTTLE_JIFFIES);
1216 				netif_dbg(dev, link, dev->net,
1217 					  "tx throttle %d\n", urb->status);
1218 			}
1219 			netif_stop_queue (dev->net);
1220 			break;
1221 		default:
1222 			netif_dbg(dev, tx_err, dev->net,
1223 				  "tx err %d\n", entry->urb->status);
1224 			break;
1225 		}
1226 	}
1227 
1228 	usb_autopm_put_interface_async(dev->intf);
1229 	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1230 }
1231 
1232 /*-------------------------------------------------------------------------*/
1233 
1234 void usbnet_tx_timeout (struct net_device *net)
1235 {
1236 	struct usbnet		*dev = netdev_priv(net);
1237 
1238 	unlink_urbs (dev, &dev->txq);
1239 	tasklet_schedule (&dev->bh);
1240 	/* this needs to be handled individually because the generic layer
1241 	 * doesn't know what is sufficient and could not restore private
1242 	 * information if a remedy of an unconditional reset were used.
1243 	 */
1244 	if (dev->driver_info->recover)
1245 		(dev->driver_info->recover)(dev);
1246 }
1247 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1248 
1249 /*-------------------------------------------------------------------------*/
1250 
1251 static int build_dma_sg(const struct sk_buff *skb, struct urb *urb)
1252 {
1253 	unsigned num_sgs, total_len = 0;
1254 	int i, s = 0;
1255 
1256 	num_sgs = skb_shinfo(skb)->nr_frags + 1;
1257 	if (num_sgs == 1)
1258 		return 0;
1259 
1260 	/* reserve one for zero packet */
1261 	urb->sg = kmalloc((num_sgs + 1) * sizeof(struct scatterlist),
1262 			  GFP_ATOMIC);
1263 	if (!urb->sg)
1264 		return -ENOMEM;
1265 
1266 	urb->num_sgs = num_sgs;
1267 	sg_init_table(urb->sg, urb->num_sgs + 1);
1268 
1269 	sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb));
1270 	total_len += skb_headlen(skb);
1271 
1272 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1273 		struct skb_frag_struct *f = &skb_shinfo(skb)->frags[i];
1274 
1275 		total_len += skb_frag_size(f);
1276 		sg_set_page(&urb->sg[i + s], f->page.p, f->size,
1277 				f->page_offset);
1278 	}
1279 	urb->transfer_buffer_length = total_len;
1280 
1281 	return 1;
1282 }
1283 
1284 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1285 				     struct net_device *net)
1286 {
1287 	struct usbnet		*dev = netdev_priv(net);
1288 	unsigned int			length;
1289 	struct urb		*urb = NULL;
1290 	struct skb_data		*entry;
1291 	struct driver_info	*info = dev->driver_info;
1292 	unsigned long		flags;
1293 	int retval;
1294 
1295 	if (skb)
1296 		skb_tx_timestamp(skb);
1297 
1298 	// some devices want funky USB-level framing, for
1299 	// win32 driver (usually) and/or hardware quirks
1300 	if (info->tx_fixup) {
1301 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1302 		if (!skb) {
1303 			/* packet collected; minidriver waiting for more */
1304 			if (info->flags & FLAG_MULTI_PACKET)
1305 				goto not_drop;
1306 			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1307 			goto drop;
1308 		}
1309 	}
1310 
1311 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1312 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1313 		goto drop;
1314 	}
1315 
1316 	entry = (struct skb_data *) skb->cb;
1317 	entry->urb = urb;
1318 	entry->dev = dev;
1319 
1320 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1321 			skb->data, skb->len, tx_complete, skb);
1322 	if (dev->can_dma_sg) {
1323 		if (build_dma_sg(skb, urb) < 0)
1324 			goto drop;
1325 	}
1326 	length = urb->transfer_buffer_length;
1327 
1328 	/* don't assume the hardware handles USB_ZERO_PACKET
1329 	 * NOTE:  strictly conforming cdc-ether devices should expect
1330 	 * the ZLP here, but ignore the one-byte packet.
1331 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1332 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1333 	 * packet itself if needed.
1334 	 */
1335 	if (length % dev->maxpacket == 0) {
1336 		if (!(info->flags & FLAG_SEND_ZLP)) {
1337 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1338 				length++;
1339 				if (skb_tailroom(skb) && !urb->num_sgs) {
1340 					skb->data[skb->len] = 0;
1341 					__skb_put(skb, 1);
1342 				} else if (urb->num_sgs)
1343 					sg_set_buf(&urb->sg[urb->num_sgs++],
1344 							dev->padding_pkt, 1);
1345 			}
1346 		} else
1347 			urb->transfer_flags |= URB_ZERO_PACKET;
1348 	}
1349 	urb->transfer_buffer_length = length;
1350 
1351 	if (info->flags & FLAG_MULTI_PACKET) {
1352 		/* Driver has set number of packets and a length delta.
1353 		 * Calculate the complete length and ensure that it's
1354 		 * positive.
1355 		 */
1356 		entry->length += length;
1357 		if (WARN_ON_ONCE(entry->length <= 0))
1358 			entry->length = length;
1359 	} else {
1360 		usbnet_set_skb_tx_stats(skb, 1, length);
1361 	}
1362 
1363 	spin_lock_irqsave(&dev->txq.lock, flags);
1364 	retval = usb_autopm_get_interface_async(dev->intf);
1365 	if (retval < 0) {
1366 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1367 		goto drop;
1368 	}
1369 
1370 #ifdef CONFIG_PM
1371 	/* if this triggers the device is still a sleep */
1372 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1373 		/* transmission will be done in resume */
1374 		usb_anchor_urb(urb, &dev->deferred);
1375 		/* no use to process more packets */
1376 		netif_stop_queue(net);
1377 		usb_put_urb(urb);
1378 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1379 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1380 		goto deferred;
1381 	}
1382 #endif
1383 
1384 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1385 	case -EPIPE:
1386 		netif_stop_queue (net);
1387 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1388 		usb_autopm_put_interface_async(dev->intf);
1389 		break;
1390 	default:
1391 		usb_autopm_put_interface_async(dev->intf);
1392 		netif_dbg(dev, tx_err, dev->net,
1393 			  "tx: submit urb err %d\n", retval);
1394 		break;
1395 	case 0:
1396 		net->trans_start = jiffies;
1397 		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1398 		if (dev->txq.qlen >= TX_QLEN (dev))
1399 			netif_stop_queue (net);
1400 	}
1401 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1402 
1403 	if (retval) {
1404 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1405 drop:
1406 		dev->net->stats.tx_dropped++;
1407 not_drop:
1408 		if (skb)
1409 			dev_kfree_skb_any (skb);
1410 		if (urb) {
1411 			kfree(urb->sg);
1412 			usb_free_urb(urb);
1413 		}
1414 	} else
1415 		netif_dbg(dev, tx_queued, dev->net,
1416 			  "> tx, len %u, type 0x%x\n", length, skb->protocol);
1417 #ifdef CONFIG_PM
1418 deferred:
1419 #endif
1420 	return NETDEV_TX_OK;
1421 }
1422 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1423 
1424 static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1425 {
1426 	struct urb	*urb;
1427 	int		i;
1428 	int		ret = 0;
1429 
1430 	/* don't refill the queue all at once */
1431 	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1432 		urb = usb_alloc_urb(0, flags);
1433 		if (urb != NULL) {
1434 			ret = rx_submit(dev, urb, flags);
1435 			if (ret)
1436 				goto err;
1437 		} else {
1438 			ret = -ENOMEM;
1439 			goto err;
1440 		}
1441 	}
1442 err:
1443 	return ret;
1444 }
1445 
1446 /*-------------------------------------------------------------------------*/
1447 
1448 // tasklet (work deferred from completions, in_irq) or timer
1449 
1450 static void usbnet_bh (unsigned long param)
1451 {
1452 	struct usbnet		*dev = (struct usbnet *) param;
1453 	struct sk_buff		*skb;
1454 	struct skb_data		*entry;
1455 
1456 	while ((skb = skb_dequeue (&dev->done))) {
1457 		entry = (struct skb_data *) skb->cb;
1458 		switch (entry->state) {
1459 		case rx_done:
1460 			entry->state = rx_cleanup;
1461 			rx_process (dev, skb);
1462 			continue;
1463 		case tx_done:
1464 			kfree(entry->urb->sg);
1465 		case rx_cleanup:
1466 			usb_free_urb (entry->urb);
1467 			dev_kfree_skb (skb);
1468 			continue;
1469 		default:
1470 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1471 		}
1472 	}
1473 
1474 	/* restart RX again after disabling due to high error rate */
1475 	clear_bit(EVENT_RX_KILL, &dev->flags);
1476 
1477 	/* waiting for all pending urbs to complete?
1478 	 * only then can we forgo submitting anew
1479 	 */
1480 	if (waitqueue_active(&dev->wait)) {
1481 		if (dev->txq.qlen + dev->rxq.qlen + dev->done.qlen == 0)
1482 			wake_up_all(&dev->wait);
1483 
1484 	// or are we maybe short a few urbs?
1485 	} else if (netif_running (dev->net) &&
1486 		   netif_device_present (dev->net) &&
1487 		   netif_carrier_ok(dev->net) &&
1488 		   !timer_pending (&dev->delay) &&
1489 		   !test_bit (EVENT_RX_HALT, &dev->flags)) {
1490 		int	temp = dev->rxq.qlen;
1491 
1492 		if (temp < RX_QLEN(dev)) {
1493 			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1494 				return;
1495 			if (temp != dev->rxq.qlen)
1496 				netif_dbg(dev, link, dev->net,
1497 					  "rxqlen %d --> %d\n",
1498 					  temp, dev->rxq.qlen);
1499 			if (dev->rxq.qlen < RX_QLEN(dev))
1500 				tasklet_schedule (&dev->bh);
1501 		}
1502 		if (dev->txq.qlen < TX_QLEN (dev))
1503 			netif_wake_queue (dev->net);
1504 	}
1505 }
1506 
1507 
1508 /*-------------------------------------------------------------------------
1509  *
1510  * USB Device Driver support
1511  *
1512  *-------------------------------------------------------------------------*/
1513 
1514 // precondition: never called in_interrupt
1515 
1516 void usbnet_disconnect (struct usb_interface *intf)
1517 {
1518 	struct usbnet		*dev;
1519 	struct usb_device	*xdev;
1520 	struct net_device	*net;
1521 
1522 	dev = usb_get_intfdata(intf);
1523 	usb_set_intfdata(intf, NULL);
1524 	if (!dev)
1525 		return;
1526 
1527 	xdev = interface_to_usbdev (intf);
1528 
1529 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1530 		   intf->dev.driver->name,
1531 		   xdev->bus->bus_name, xdev->devpath,
1532 		   dev->driver_info->description);
1533 
1534 	net = dev->net;
1535 	unregister_netdev (net);
1536 
1537 	cancel_work_sync(&dev->kevent);
1538 
1539 	usb_scuttle_anchored_urbs(&dev->deferred);
1540 
1541 	if (dev->driver_info->unbind)
1542 		dev->driver_info->unbind (dev, intf);
1543 
1544 	usb_kill_urb(dev->interrupt);
1545 	usb_free_urb(dev->interrupt);
1546 	kfree(dev->padding_pkt);
1547 
1548 	free_netdev(net);
1549 }
1550 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1551 
1552 static const struct net_device_ops usbnet_netdev_ops = {
1553 	.ndo_open		= usbnet_open,
1554 	.ndo_stop		= usbnet_stop,
1555 	.ndo_start_xmit		= usbnet_start_xmit,
1556 	.ndo_tx_timeout		= usbnet_tx_timeout,
1557 	.ndo_set_rx_mode	= usbnet_set_rx_mode,
1558 	.ndo_change_mtu		= usbnet_change_mtu,
1559 	.ndo_set_mac_address 	= eth_mac_addr,
1560 	.ndo_validate_addr	= eth_validate_addr,
1561 };
1562 
1563 /*-------------------------------------------------------------------------*/
1564 
1565 // precondition: never called in_interrupt
1566 
1567 static struct device_type wlan_type = {
1568 	.name	= "wlan",
1569 };
1570 
1571 static struct device_type wwan_type = {
1572 	.name	= "wwan",
1573 };
1574 
1575 int
1576 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1577 {
1578 	struct usbnet			*dev;
1579 	struct net_device		*net;
1580 	struct usb_host_interface	*interface;
1581 	struct driver_info		*info;
1582 	struct usb_device		*xdev;
1583 	int				status;
1584 	const char			*name;
1585 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1586 
1587 	/* usbnet already took usb runtime pm, so have to enable the feature
1588 	 * for usb interface, otherwise usb_autopm_get_interface may return
1589 	 * failure if RUNTIME_PM is enabled.
1590 	 */
1591 	if (!driver->supports_autosuspend) {
1592 		driver->supports_autosuspend = 1;
1593 		pm_runtime_enable(&udev->dev);
1594 	}
1595 
1596 	name = udev->dev.driver->name;
1597 	info = (struct driver_info *) prod->driver_info;
1598 	if (!info) {
1599 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1600 		return -ENODEV;
1601 	}
1602 	xdev = interface_to_usbdev (udev);
1603 	interface = udev->cur_altsetting;
1604 
1605 	status = -ENOMEM;
1606 
1607 	// set up our own records
1608 	net = alloc_etherdev(sizeof(*dev));
1609 	if (!net)
1610 		goto out;
1611 
1612 	/* netdev_printk() needs this so do it as early as possible */
1613 	SET_NETDEV_DEV(net, &udev->dev);
1614 
1615 	dev = netdev_priv(net);
1616 	dev->udev = xdev;
1617 	dev->intf = udev;
1618 	dev->driver_info = info;
1619 	dev->driver_name = name;
1620 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1621 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1622 	init_waitqueue_head(&dev->wait);
1623 	skb_queue_head_init (&dev->rxq);
1624 	skb_queue_head_init (&dev->txq);
1625 	skb_queue_head_init (&dev->done);
1626 	skb_queue_head_init(&dev->rxq_pause);
1627 	dev->bh.func = usbnet_bh;
1628 	dev->bh.data = (unsigned long) dev;
1629 	INIT_WORK (&dev->kevent, usbnet_deferred_kevent);
1630 	init_usb_anchor(&dev->deferred);
1631 	dev->delay.function = usbnet_bh;
1632 	dev->delay.data = (unsigned long) dev;
1633 	init_timer (&dev->delay);
1634 	mutex_init (&dev->phy_mutex);
1635 	mutex_init(&dev->interrupt_mutex);
1636 	dev->interrupt_count = 0;
1637 
1638 	dev->net = net;
1639 	strcpy (net->name, "usb%d");
1640 	memcpy (net->dev_addr, node_id, sizeof node_id);
1641 
1642 	/* rx and tx sides can use different message sizes;
1643 	 * bind() should set rx_urb_size in that case.
1644 	 */
1645 	dev->hard_mtu = net->mtu + net->hard_header_len;
1646 #if 0
1647 // dma_supported() is deeply broken on almost all architectures
1648 	// possible with some EHCI controllers
1649 	if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1650 		net->features |= NETIF_F_HIGHDMA;
1651 #endif
1652 
1653 	net->netdev_ops = &usbnet_netdev_ops;
1654 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1655 	net->ethtool_ops = &usbnet_ethtool_ops;
1656 
1657 	// allow device-specific bind/init procedures
1658 	// NOTE net->name still not usable ...
1659 	if (info->bind) {
1660 		status = info->bind (dev, udev);
1661 		if (status < 0)
1662 			goto out1;
1663 
1664 		// heuristic:  "usb%d" for links we know are two-host,
1665 		// else "eth%d" when there's reasonable doubt.  userspace
1666 		// can rename the link if it knows better.
1667 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1668 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1669 		     (net->dev_addr [0] & 0x02) == 0))
1670 			strcpy (net->name, "eth%d");
1671 		/* WLAN devices should always be named "wlan%d" */
1672 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1673 			strcpy(net->name, "wlan%d");
1674 		/* WWAN devices should always be named "wwan%d" */
1675 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1676 			strcpy(net->name, "wwan%d");
1677 
1678 		/* devices that cannot do ARP */
1679 		if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1680 			net->flags |= IFF_NOARP;
1681 
1682 		/* maybe the remote can't receive an Ethernet MTU */
1683 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1684 			net->mtu = dev->hard_mtu - net->hard_header_len;
1685 	} else if (!info->in || !info->out)
1686 		status = usbnet_get_endpoints (dev, udev);
1687 	else {
1688 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1689 		dev->out = usb_sndbulkpipe (xdev, info->out);
1690 		if (!(info->flags & FLAG_NO_SETINT))
1691 			status = usb_set_interface (xdev,
1692 				interface->desc.bInterfaceNumber,
1693 				interface->desc.bAlternateSetting);
1694 		else
1695 			status = 0;
1696 
1697 	}
1698 	if (status >= 0 && dev->status)
1699 		status = init_status (dev, udev);
1700 	if (status < 0)
1701 		goto out3;
1702 
1703 	if (!dev->rx_urb_size)
1704 		dev->rx_urb_size = dev->hard_mtu;
1705 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1706 
1707 	/* let userspace know we have a random address */
1708 	if (ether_addr_equal(net->dev_addr, node_id))
1709 		net->addr_assign_type = NET_ADDR_RANDOM;
1710 
1711 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1712 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1713 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1714 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1715 
1716 	/* initialize max rx_qlen and tx_qlen */
1717 	usbnet_update_max_qlen(dev);
1718 
1719 	if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&
1720 		!(info->flags & FLAG_MULTI_PACKET)) {
1721 		dev->padding_pkt = kzalloc(1, GFP_KERNEL);
1722 		if (!dev->padding_pkt) {
1723 			status = -ENOMEM;
1724 			goto out4;
1725 		}
1726 	}
1727 
1728 	status = register_netdev (net);
1729 	if (status)
1730 		goto out5;
1731 	netif_info(dev, probe, dev->net,
1732 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1733 		   udev->dev.driver->name,
1734 		   xdev->bus->bus_name, xdev->devpath,
1735 		   dev->driver_info->description,
1736 		   net->dev_addr);
1737 
1738 	// ok, it's ready to go.
1739 	usb_set_intfdata (udev, dev);
1740 
1741 	netif_device_attach (net);
1742 
1743 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1744 		usbnet_link_change(dev, 0, 0);
1745 
1746 	return 0;
1747 
1748 out5:
1749 	kfree(dev->padding_pkt);
1750 out4:
1751 	usb_free_urb(dev->interrupt);
1752 out3:
1753 	if (info->unbind)
1754 		info->unbind (dev, udev);
1755 out1:
1756 	free_netdev(net);
1757 out:
1758 	return status;
1759 }
1760 EXPORT_SYMBOL_GPL(usbnet_probe);
1761 
1762 /*-------------------------------------------------------------------------*/
1763 
1764 /*
1765  * suspend the whole driver as soon as the first interface is suspended
1766  * resume only when the last interface is resumed
1767  */
1768 
1769 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1770 {
1771 	struct usbnet		*dev = usb_get_intfdata(intf);
1772 
1773 	if (!dev->suspend_count++) {
1774 		spin_lock_irq(&dev->txq.lock);
1775 		/* don't autosuspend while transmitting */
1776 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1777 			dev->suspend_count--;
1778 			spin_unlock_irq(&dev->txq.lock);
1779 			return -EBUSY;
1780 		} else {
1781 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1782 			spin_unlock_irq(&dev->txq.lock);
1783 		}
1784 		/*
1785 		 * accelerate emptying of the rx and queues, to avoid
1786 		 * having everything error out.
1787 		 */
1788 		netif_device_detach (dev->net);
1789 		usbnet_terminate_urbs(dev);
1790 		__usbnet_status_stop_force(dev);
1791 
1792 		/*
1793 		 * reattach so runtime management can use and
1794 		 * wake the device
1795 		 */
1796 		netif_device_attach (dev->net);
1797 	}
1798 	return 0;
1799 }
1800 EXPORT_SYMBOL_GPL(usbnet_suspend);
1801 
1802 int usbnet_resume (struct usb_interface *intf)
1803 {
1804 	struct usbnet		*dev = usb_get_intfdata(intf);
1805 	struct sk_buff          *skb;
1806 	struct urb              *res;
1807 	int                     retval;
1808 
1809 	if (!--dev->suspend_count) {
1810 		/* resume interrupt URB if it was previously submitted */
1811 		__usbnet_status_start_force(dev, GFP_NOIO);
1812 
1813 		spin_lock_irq(&dev->txq.lock);
1814 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1815 
1816 			skb = (struct sk_buff *)res->context;
1817 			retval = usb_submit_urb(res, GFP_ATOMIC);
1818 			if (retval < 0) {
1819 				dev_kfree_skb_any(skb);
1820 				kfree(res->sg);
1821 				usb_free_urb(res);
1822 				usb_autopm_put_interface_async(dev->intf);
1823 			} else {
1824 				dev->net->trans_start = jiffies;
1825 				__skb_queue_tail(&dev->txq, skb);
1826 			}
1827 		}
1828 
1829 		smp_mb();
1830 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1831 		spin_unlock_irq(&dev->txq.lock);
1832 
1833 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1834 			/* handle remote wakeup ASAP
1835 			 * we cannot race against stop
1836 			 */
1837 			if (netif_device_present(dev->net) &&
1838 				!timer_pending(&dev->delay) &&
1839 				!test_bit(EVENT_RX_HALT, &dev->flags))
1840 					rx_alloc_submit(dev, GFP_NOIO);
1841 
1842 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1843 				netif_tx_wake_all_queues(dev->net);
1844 			tasklet_schedule (&dev->bh);
1845 		}
1846 	}
1847 
1848 	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1849 		usb_autopm_get_interface_no_resume(intf);
1850 
1851 	return 0;
1852 }
1853 EXPORT_SYMBOL_GPL(usbnet_resume);
1854 
1855 /*
1856  * Either a subdriver implements manage_power, then it is assumed to always
1857  * be ready to be suspended or it reports the readiness to be suspended
1858  * explicitly
1859  */
1860 void usbnet_device_suggests_idle(struct usbnet *dev)
1861 {
1862 	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1863 		dev->intf->needs_remote_wakeup = 1;
1864 		usb_autopm_put_interface_async(dev->intf);
1865 	}
1866 }
1867 EXPORT_SYMBOL(usbnet_device_suggests_idle);
1868 
1869 /*
1870  * For devices that can do without special commands
1871  */
1872 int usbnet_manage_power(struct usbnet *dev, int on)
1873 {
1874 	dev->intf->needs_remote_wakeup = on;
1875 	return 0;
1876 }
1877 EXPORT_SYMBOL(usbnet_manage_power);
1878 
1879 void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
1880 {
1881 	/* update link after link is reseted */
1882 	if (link && !need_reset)
1883 		netif_carrier_on(dev->net);
1884 	else
1885 		netif_carrier_off(dev->net);
1886 
1887 	if (need_reset && link)
1888 		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
1889 	else
1890 		usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
1891 }
1892 EXPORT_SYMBOL(usbnet_link_change);
1893 
1894 /*-------------------------------------------------------------------------*/
1895 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1896 			     u16 value, u16 index, void *data, u16 size)
1897 {
1898 	void *buf = NULL;
1899 	int err = -ENOMEM;
1900 
1901 	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
1902 		   " value=0x%04x index=0x%04x size=%d\n",
1903 		   cmd, reqtype, value, index, size);
1904 
1905 	if (data) {
1906 		buf = kmalloc(size, GFP_KERNEL);
1907 		if (!buf)
1908 			goto out;
1909 	}
1910 
1911 	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
1912 			      cmd, reqtype, value, index, buf, size,
1913 			      USB_CTRL_GET_TIMEOUT);
1914 	if (err > 0 && err <= size)
1915 		memcpy(data, buf, err);
1916 	kfree(buf);
1917 out:
1918 	return err;
1919 }
1920 
1921 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1922 			      u16 value, u16 index, const void *data,
1923 			      u16 size)
1924 {
1925 	void *buf = NULL;
1926 	int err = -ENOMEM;
1927 
1928 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
1929 		   " value=0x%04x index=0x%04x size=%d\n",
1930 		   cmd, reqtype, value, index, size);
1931 
1932 	if (data) {
1933 		buf = kmemdup(data, size, GFP_KERNEL);
1934 		if (!buf)
1935 			goto out;
1936 	}
1937 
1938 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
1939 			      cmd, reqtype, value, index, buf, size,
1940 			      USB_CTRL_SET_TIMEOUT);
1941 	kfree(buf);
1942 
1943 out:
1944 	return err;
1945 }
1946 
1947 /*
1948  * The function can't be called inside suspend/resume callback,
1949  * otherwise deadlock will be caused.
1950  */
1951 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1952 		    u16 value, u16 index, void *data, u16 size)
1953 {
1954 	int ret;
1955 
1956 	if (usb_autopm_get_interface(dev->intf) < 0)
1957 		return -ENODEV;
1958 	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
1959 				data, size);
1960 	usb_autopm_put_interface(dev->intf);
1961 	return ret;
1962 }
1963 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
1964 
1965 /*
1966  * The function can't be called inside suspend/resume callback,
1967  * otherwise deadlock will be caused.
1968  */
1969 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1970 		     u16 value, u16 index, const void *data, u16 size)
1971 {
1972 	int ret;
1973 
1974 	if (usb_autopm_get_interface(dev->intf) < 0)
1975 		return -ENODEV;
1976 	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
1977 				 data, size);
1978 	usb_autopm_put_interface(dev->intf);
1979 	return ret;
1980 }
1981 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
1982 
1983 /*
1984  * The function can be called inside suspend/resume callback safely
1985  * and should only be called by suspend/resume callback generally.
1986  */
1987 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
1988 			  u16 value, u16 index, void *data, u16 size)
1989 {
1990 	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
1991 				 data, size);
1992 }
1993 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
1994 
1995 /*
1996  * The function can be called inside suspend/resume callback safely
1997  * and should only be called by suspend/resume callback generally.
1998  */
1999 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2000 			  u16 value, u16 index, const void *data,
2001 			  u16 size)
2002 {
2003 	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2004 				  data, size);
2005 }
2006 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
2007 
2008 static void usbnet_async_cmd_cb(struct urb *urb)
2009 {
2010 	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
2011 	int status = urb->status;
2012 
2013 	if (status < 0)
2014 		dev_dbg(&urb->dev->dev, "%s failed with %d",
2015 			__func__, status);
2016 
2017 	kfree(req);
2018 	usb_free_urb(urb);
2019 }
2020 
2021 /*
2022  * The caller must make sure that device can't be put into suspend
2023  * state until the control URB completes.
2024  */
2025 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
2026 			   u16 value, u16 index, const void *data, u16 size)
2027 {
2028 	struct usb_ctrlrequest *req = NULL;
2029 	struct urb *urb;
2030 	int err = -ENOMEM;
2031 	void *buf = NULL;
2032 
2033 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2034 		   " value=0x%04x index=0x%04x size=%d\n",
2035 		   cmd, reqtype, value, index, size);
2036 
2037 	urb = usb_alloc_urb(0, GFP_ATOMIC);
2038 	if (!urb) {
2039 		netdev_err(dev->net, "Error allocating URB in"
2040 			   " %s!\n", __func__);
2041 		goto fail;
2042 	}
2043 
2044 	if (data) {
2045 		buf = kmemdup(data, size, GFP_ATOMIC);
2046 		if (!buf) {
2047 			netdev_err(dev->net, "Error allocating buffer"
2048 				   " in %s!\n", __func__);
2049 			goto fail_free;
2050 		}
2051 	}
2052 
2053 	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
2054 	if (!req)
2055 		goto fail_free_buf;
2056 
2057 	req->bRequestType = reqtype;
2058 	req->bRequest = cmd;
2059 	req->wValue = cpu_to_le16(value);
2060 	req->wIndex = cpu_to_le16(index);
2061 	req->wLength = cpu_to_le16(size);
2062 
2063 	usb_fill_control_urb(urb, dev->udev,
2064 			     usb_sndctrlpipe(dev->udev, 0),
2065 			     (void *)req, buf, size,
2066 			     usbnet_async_cmd_cb, req);
2067 	urb->transfer_flags |= URB_FREE_BUFFER;
2068 
2069 	err = usb_submit_urb(urb, GFP_ATOMIC);
2070 	if (err < 0) {
2071 		netdev_err(dev->net, "Error submitting the control"
2072 			   " message: status=%d\n", err);
2073 		goto fail_free;
2074 	}
2075 	return 0;
2076 
2077 fail_free_buf:
2078 	kfree(buf);
2079 fail_free:
2080 	kfree(req);
2081 	usb_free_urb(urb);
2082 fail:
2083 	return err;
2084 
2085 }
2086 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
2087 /*-------------------------------------------------------------------------*/
2088 
2089 static int __init usbnet_init(void)
2090 {
2091 	/* Compiler should optimize this out. */
2092 	BUILD_BUG_ON(
2093 		FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
2094 
2095 	eth_random_addr(node_id);
2096 	return 0;
2097 }
2098 module_init(usbnet_init);
2099 
2100 static void __exit usbnet_exit(void)
2101 {
2102 }
2103 module_exit(usbnet_exit);
2104 
2105 MODULE_AUTHOR("David Brownell");
2106 MODULE_DESCRIPTION("USB network driver framework");
2107 MODULE_LICENSE("GPL");
2108