xref: /linux/drivers/net/usb/usbnet.c (revision a8b70ccf10e38775785d9cb12ead916474549f99)
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 /* use ethtool to change the level for any given device */
86 static int msg_level = -1;
87 module_param (msg_level, int, 0);
88 MODULE_PARM_DESC (msg_level, "Override default message level");
89 
90 /*-------------------------------------------------------------------------*/
91 
92 /* handles CDC Ethernet and many other network "bulk data" interfaces */
93 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
94 {
95 	int				tmp;
96 	struct usb_host_interface	*alt = NULL;
97 	struct usb_host_endpoint	*in = NULL, *out = NULL;
98 	struct usb_host_endpoint	*status = NULL;
99 
100 	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
101 		unsigned	ep;
102 
103 		in = out = status = NULL;
104 		alt = intf->altsetting + tmp;
105 
106 		/* take the first altsetting with in-bulk + out-bulk;
107 		 * remember any status endpoint, just in case;
108 		 * ignore other endpoints and altsettings.
109 		 */
110 		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
111 			struct usb_host_endpoint	*e;
112 			int				intr = 0;
113 
114 			e = alt->endpoint + ep;
115 			switch (e->desc.bmAttributes) {
116 			case USB_ENDPOINT_XFER_INT:
117 				if (!usb_endpoint_dir_in(&e->desc))
118 					continue;
119 				intr = 1;
120 				/* FALLTHROUGH */
121 			case USB_ENDPOINT_XFER_BULK:
122 				break;
123 			default:
124 				continue;
125 			}
126 			if (usb_endpoint_dir_in(&e->desc)) {
127 				if (!intr && !in)
128 					in = e;
129 				else if (intr && !status)
130 					status = e;
131 			} else {
132 				if (!out)
133 					out = e;
134 			}
135 		}
136 		if (in && out)
137 			break;
138 	}
139 	if (!alt || !in || !out)
140 		return -EINVAL;
141 
142 	if (alt->desc.bAlternateSetting != 0 ||
143 	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
144 		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
145 				alt->desc.bAlternateSetting);
146 		if (tmp < 0)
147 			return tmp;
148 	}
149 
150 	dev->in = usb_rcvbulkpipe (dev->udev,
151 			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
152 	dev->out = usb_sndbulkpipe (dev->udev,
153 			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
154 	dev->status = status;
155 	return 0;
156 }
157 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
158 
159 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
160 {
161 	int 		tmp = -1, ret;
162 	unsigned char	buf [13];
163 
164 	ret = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
165 	if (ret == 12)
166 		tmp = hex2bin(dev->net->dev_addr, buf, 6);
167 	if (tmp < 0) {
168 		dev_dbg(&dev->udev->dev,
169 			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
170 		if (ret >= 0)
171 			ret = -EINVAL;
172 		return ret;
173 	}
174 	return 0;
175 }
176 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
177 
178 static void intr_complete (struct urb *urb)
179 {
180 	struct usbnet	*dev = urb->context;
181 	int		status = urb->status;
182 
183 	switch (status) {
184 	/* success */
185 	case 0:
186 		dev->driver_info->status(dev, urb);
187 		break;
188 
189 	/* software-driven interface shutdown */
190 	case -ENOENT:		/* urb killed */
191 	case -ESHUTDOWN:	/* hardware gone */
192 		netif_dbg(dev, ifdown, dev->net,
193 			  "intr shutdown, code %d\n", status);
194 		return;
195 
196 	/* NOTE:  not throttling like RX/TX, since this endpoint
197 	 * already polls infrequently
198 	 */
199 	default:
200 		netdev_dbg(dev->net, "intr status %d\n", status);
201 		break;
202 	}
203 
204 	status = usb_submit_urb (urb, GFP_ATOMIC);
205 	if (status != 0)
206 		netif_err(dev, timer, dev->net,
207 			  "intr resubmit --> %d\n", status);
208 }
209 
210 static int init_status (struct usbnet *dev, struct usb_interface *intf)
211 {
212 	char		*buf = NULL;
213 	unsigned	pipe = 0;
214 	unsigned	maxp;
215 	unsigned	period;
216 
217 	if (!dev->driver_info->status)
218 		return 0;
219 
220 	pipe = usb_rcvintpipe (dev->udev,
221 			dev->status->desc.bEndpointAddress
222 				& USB_ENDPOINT_NUMBER_MASK);
223 	maxp = usb_maxpacket (dev->udev, pipe, 0);
224 
225 	/* avoid 1 msec chatter:  min 8 msec poll rate */
226 	period = max ((int) dev->status->desc.bInterval,
227 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
228 
229 	buf = kmalloc (maxp, GFP_KERNEL);
230 	if (buf) {
231 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
232 		if (!dev->interrupt) {
233 			kfree (buf);
234 			return -ENOMEM;
235 		} else {
236 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
237 				buf, maxp, intr_complete, dev, period);
238 			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
239 			dev_dbg(&intf->dev,
240 				"status ep%din, %d bytes period %d\n",
241 				usb_pipeendpoint(pipe), maxp, period);
242 		}
243 	}
244 	return 0;
245 }
246 
247 /* Submit the interrupt URB if not previously submitted, increasing refcount */
248 int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
249 {
250 	int ret = 0;
251 
252 	WARN_ON_ONCE(dev->interrupt == NULL);
253 	if (dev->interrupt) {
254 		mutex_lock(&dev->interrupt_mutex);
255 
256 		if (++dev->interrupt_count == 1)
257 			ret = usb_submit_urb(dev->interrupt, mem_flags);
258 
259 		dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
260 			dev->interrupt_count);
261 		mutex_unlock(&dev->interrupt_mutex);
262 	}
263 	return ret;
264 }
265 EXPORT_SYMBOL_GPL(usbnet_status_start);
266 
267 /* For resume; submit interrupt URB if previously submitted */
268 static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
269 {
270 	int ret = 0;
271 
272 	mutex_lock(&dev->interrupt_mutex);
273 	if (dev->interrupt_count) {
274 		ret = usb_submit_urb(dev->interrupt, mem_flags);
275 		dev_dbg(&dev->udev->dev,
276 			"submitted interrupt URB for resume\n");
277 	}
278 	mutex_unlock(&dev->interrupt_mutex);
279 	return ret;
280 }
281 
282 /* Kill the interrupt URB if all submitters want it killed */
283 void usbnet_status_stop(struct usbnet *dev)
284 {
285 	if (dev->interrupt) {
286 		mutex_lock(&dev->interrupt_mutex);
287 		WARN_ON(dev->interrupt_count == 0);
288 
289 		if (dev->interrupt_count && --dev->interrupt_count == 0)
290 			usb_kill_urb(dev->interrupt);
291 
292 		dev_dbg(&dev->udev->dev,
293 			"decremented interrupt URB count to %d\n",
294 			dev->interrupt_count);
295 		mutex_unlock(&dev->interrupt_mutex);
296 	}
297 }
298 EXPORT_SYMBOL_GPL(usbnet_status_stop);
299 
300 /* For suspend; always kill interrupt URB */
301 static void __usbnet_status_stop_force(struct usbnet *dev)
302 {
303 	if (dev->interrupt) {
304 		mutex_lock(&dev->interrupt_mutex);
305 		usb_kill_urb(dev->interrupt);
306 		dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
307 		mutex_unlock(&dev->interrupt_mutex);
308 	}
309 }
310 
311 /* Passes this packet up the stack, updating its accounting.
312  * Some link protocols batch packets, so their rx_fixup paths
313  * can return clones as well as just modify the original skb.
314  */
315 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
316 {
317 	struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->stats64);
318 	unsigned long flags;
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 	/* only update if unset to allow minidriver rx_fixup override */
327 	if (skb->protocol == 0)
328 		skb->protocol = eth_type_trans (skb, dev->net);
329 
330 	flags = u64_stats_update_begin_irqsave(&stats64->syncp);
331 	stats64->rx_packets++;
332 	stats64->rx_bytes += skb->len;
333 	u64_stats_update_end_irqrestore(&stats64->syncp, flags);
334 
335 	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
336 		  skb->len + sizeof (struct ethhdr), skb->protocol);
337 	memset (skb->cb, 0, sizeof (struct skb_data));
338 
339 	if (skb_defer_rx_timestamp(skb))
340 		return;
341 
342 	status = netif_rx (skb);
343 	if (status != NET_RX_SUCCESS)
344 		netif_dbg(dev, rx_err, dev->net,
345 			  "netif_rx status %d\n", status);
346 }
347 EXPORT_SYMBOL_GPL(usbnet_skb_return);
348 
349 /* must be called if hard_mtu or rx_urb_size changed */
350 void usbnet_update_max_qlen(struct usbnet *dev)
351 {
352 	enum usb_device_speed speed = dev->udev->speed;
353 
354 	switch (speed) {
355 	case USB_SPEED_HIGH:
356 		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
357 		dev->tx_qlen = MAX_QUEUE_MEMORY / dev->hard_mtu;
358 		break;
359 	case USB_SPEED_SUPER:
360 	case USB_SPEED_SUPER_PLUS:
361 		/*
362 		 * Not take default 5ms qlen for super speed HC to
363 		 * save memory, and iperf tests show 2.5ms qlen can
364 		 * work well
365 		 */
366 		dev->rx_qlen = 5 * MAX_QUEUE_MEMORY / dev->rx_urb_size;
367 		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
368 		break;
369 	default:
370 		dev->rx_qlen = dev->tx_qlen = 4;
371 	}
372 }
373 EXPORT_SYMBOL_GPL(usbnet_update_max_qlen);
374 
375 
376 /*-------------------------------------------------------------------------
377  *
378  * Network Device Driver (peer link to "Host Device", from USB host)
379  *
380  *-------------------------------------------------------------------------*/
381 
382 int usbnet_change_mtu (struct net_device *net, int new_mtu)
383 {
384 	struct usbnet	*dev = netdev_priv(net);
385 	int		ll_mtu = new_mtu + net->hard_header_len;
386 	int		old_hard_mtu = dev->hard_mtu;
387 	int		old_rx_urb_size = dev->rx_urb_size;
388 
389 	// no second zero-length packet read wanted after mtu-sized packets
390 	if ((ll_mtu % dev->maxpacket) == 0)
391 		return -EDOM;
392 	net->mtu = new_mtu;
393 
394 	dev->hard_mtu = net->mtu + net->hard_header_len;
395 	if (dev->rx_urb_size == old_hard_mtu) {
396 		dev->rx_urb_size = dev->hard_mtu;
397 		if (dev->rx_urb_size > old_rx_urb_size) {
398 			usbnet_pause_rx(dev);
399 			usbnet_unlink_rx_urbs(dev);
400 			usbnet_resume_rx(dev);
401 		}
402 	}
403 
404 	/* max qlen depend on hard_mtu and rx_urb_size */
405 	usbnet_update_max_qlen(dev);
406 
407 	return 0;
408 }
409 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
410 
411 /* The caller must hold list->lock */
412 static void __usbnet_queue_skb(struct sk_buff_head *list,
413 			struct sk_buff *newsk, enum skb_state state)
414 {
415 	struct skb_data *entry = (struct skb_data *) newsk->cb;
416 
417 	__skb_queue_tail(list, newsk);
418 	entry->state = state;
419 }
420 
421 /*-------------------------------------------------------------------------*/
422 
423 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
424  * completion callbacks.  2.5 should have fixed those bugs...
425  */
426 
427 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
428 		struct sk_buff_head *list, enum skb_state state)
429 {
430 	unsigned long		flags;
431 	enum skb_state 		old_state;
432 	struct skb_data *entry = (struct skb_data *) skb->cb;
433 
434 	spin_lock_irqsave(&list->lock, flags);
435 	old_state = entry->state;
436 	entry->state = state;
437 	__skb_unlink(skb, list);
438 
439 	/* defer_bh() is never called with list == &dev->done.
440 	 * spin_lock_nested() tells lockdep that it is OK to take
441 	 * dev->done.lock here with list->lock held.
442 	 */
443 	spin_lock_nested(&dev->done.lock, SINGLE_DEPTH_NESTING);
444 
445 	__skb_queue_tail(&dev->done, skb);
446 	if (dev->done.qlen == 1)
447 		tasklet_schedule(&dev->bh);
448 	spin_unlock(&dev->done.lock);
449 	spin_unlock_irqrestore(&list->lock, flags);
450 	return old_state;
451 }
452 
453 /* some work can't be done in tasklets, so we use keventd
454  *
455  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
456  * but tasklet_schedule() doesn't.  hope the failure is rare.
457  */
458 void usbnet_defer_kevent (struct usbnet *dev, int work)
459 {
460 	set_bit (work, &dev->flags);
461 	if (!schedule_work (&dev->kevent))
462 		netdev_dbg(dev->net, "kevent %d may have been dropped\n", work);
463 	else
464 		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
465 }
466 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
467 
468 /*-------------------------------------------------------------------------*/
469 
470 static void rx_complete (struct urb *urb);
471 
472 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
473 {
474 	struct sk_buff		*skb;
475 	struct skb_data		*entry;
476 	int			retval = 0;
477 	unsigned long		lockflags;
478 	size_t			size = dev->rx_urb_size;
479 
480 	/* prevent rx skb allocation when error ratio is high */
481 	if (test_bit(EVENT_RX_KILL, &dev->flags)) {
482 		usb_free_urb(urb);
483 		return -ENOLINK;
484 	}
485 
486 	if (test_bit(EVENT_NO_IP_ALIGN, &dev->flags))
487 		skb = __netdev_alloc_skb(dev->net, size, flags);
488 	else
489 		skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
490 	if (!skb) {
491 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
492 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
493 		usb_free_urb (urb);
494 		return -ENOMEM;
495 	}
496 
497 	entry = (struct skb_data *) skb->cb;
498 	entry->urb = urb;
499 	entry->dev = dev;
500 	entry->length = 0;
501 
502 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
503 		skb->data, size, rx_complete, skb);
504 
505 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
506 
507 	if (netif_running (dev->net) &&
508 	    netif_device_present (dev->net) &&
509 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
510 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
511 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
512 		case -EPIPE:
513 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
514 			break;
515 		case -ENOMEM:
516 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
517 			break;
518 		case -ENODEV:
519 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
520 			netif_device_detach (dev->net);
521 			break;
522 		case -EHOSTUNREACH:
523 			retval = -ENOLINK;
524 			break;
525 		default:
526 			netif_dbg(dev, rx_err, dev->net,
527 				  "rx submit, %d\n", retval);
528 			tasklet_schedule (&dev->bh);
529 			break;
530 		case 0:
531 			__usbnet_queue_skb(&dev->rxq, skb, rx_start);
532 		}
533 	} else {
534 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
535 		retval = -ENOLINK;
536 	}
537 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
538 	if (retval) {
539 		dev_kfree_skb_any (skb);
540 		usb_free_urb (urb);
541 	}
542 	return retval;
543 }
544 
545 
546 /*-------------------------------------------------------------------------*/
547 
548 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
549 {
550 	if (dev->driver_info->rx_fixup &&
551 	    !dev->driver_info->rx_fixup (dev, skb)) {
552 		/* With RX_ASSEMBLE, rx_fixup() must update counters */
553 		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
554 			dev->net->stats.rx_errors++;
555 		goto done;
556 	}
557 	// else network stack removes extra byte if we forced a short packet
558 
559 	/* all data was already cloned from skb inside the driver */
560 	if (dev->driver_info->flags & FLAG_MULTI_PACKET)
561 		goto done;
562 
563 	if (skb->len < ETH_HLEN) {
564 		dev->net->stats.rx_errors++;
565 		dev->net->stats.rx_length_errors++;
566 		netif_dbg(dev, rx_err, dev->net, "rx length %d\n", skb->len);
567 	} else {
568 		usbnet_skb_return(dev, skb);
569 		return;
570 	}
571 
572 done:
573 	skb_queue_tail(&dev->done, skb);
574 }
575 
576 /*-------------------------------------------------------------------------*/
577 
578 static void rx_complete (struct urb *urb)
579 {
580 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
581 	struct skb_data		*entry = (struct skb_data *) skb->cb;
582 	struct usbnet		*dev = entry->dev;
583 	int			urb_status = urb->status;
584 	enum skb_state		state;
585 
586 	skb_put (skb, urb->actual_length);
587 	state = rx_done;
588 	entry->urb = NULL;
589 
590 	switch (urb_status) {
591 	/* success */
592 	case 0:
593 		break;
594 
595 	/* stalls need manual reset. this is rare ... except that
596 	 * when going through USB 2.0 TTs, unplug appears this way.
597 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
598 	 * storm, recovering as needed.
599 	 */
600 	case -EPIPE:
601 		dev->net->stats.rx_errors++;
602 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
603 		// FALLTHROUGH
604 
605 	/* software-driven interface shutdown */
606 	case -ECONNRESET:		/* async unlink */
607 	case -ESHUTDOWN:		/* hardware gone */
608 		netif_dbg(dev, ifdown, dev->net,
609 			  "rx shutdown, code %d\n", urb_status);
610 		goto block;
611 
612 	/* we get controller i/o faults during hub_wq disconnect() delays.
613 	 * throttle down resubmits, to avoid log floods; just temporarily,
614 	 * so we still recover when the fault isn't a hub_wq delay.
615 	 */
616 	case -EPROTO:
617 	case -ETIME:
618 	case -EILSEQ:
619 		dev->net->stats.rx_errors++;
620 		if (!timer_pending (&dev->delay)) {
621 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
622 			netif_dbg(dev, link, dev->net,
623 				  "rx throttle %d\n", urb_status);
624 		}
625 block:
626 		state = rx_cleanup;
627 		entry->urb = urb;
628 		urb = NULL;
629 		break;
630 
631 	/* data overrun ... flush fifo? */
632 	case -EOVERFLOW:
633 		dev->net->stats.rx_over_errors++;
634 		// FALLTHROUGH
635 
636 	default:
637 		state = rx_cleanup;
638 		dev->net->stats.rx_errors++;
639 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
640 		break;
641 	}
642 
643 	/* stop rx if packet error rate is high */
644 	if (++dev->pkt_cnt > 30) {
645 		dev->pkt_cnt = 0;
646 		dev->pkt_err = 0;
647 	} else {
648 		if (state == rx_cleanup)
649 			dev->pkt_err++;
650 		if (dev->pkt_err > 20)
651 			set_bit(EVENT_RX_KILL, &dev->flags);
652 	}
653 
654 	state = defer_bh(dev, skb, &dev->rxq, state);
655 
656 	if (urb) {
657 		if (netif_running (dev->net) &&
658 		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
659 		    state != unlink_start) {
660 			rx_submit (dev, urb, GFP_ATOMIC);
661 			usb_mark_last_busy(dev->udev);
662 			return;
663 		}
664 		usb_free_urb (urb);
665 	}
666 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
667 }
668 
669 /*-------------------------------------------------------------------------*/
670 void usbnet_pause_rx(struct usbnet *dev)
671 {
672 	set_bit(EVENT_RX_PAUSED, &dev->flags);
673 
674 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
675 }
676 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
677 
678 void usbnet_resume_rx(struct usbnet *dev)
679 {
680 	struct sk_buff *skb;
681 	int num = 0;
682 
683 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
684 
685 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
686 		usbnet_skb_return(dev, skb);
687 		num++;
688 	}
689 
690 	tasklet_schedule(&dev->bh);
691 
692 	netif_dbg(dev, rx_status, dev->net,
693 		  "paused rx queue disabled, %d skbs requeued\n", num);
694 }
695 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
696 
697 void usbnet_purge_paused_rxq(struct usbnet *dev)
698 {
699 	skb_queue_purge(&dev->rxq_pause);
700 }
701 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
702 
703 /*-------------------------------------------------------------------------*/
704 
705 // unlink pending rx/tx; completion handlers do all other cleanup
706 
707 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
708 {
709 	unsigned long		flags;
710 	struct sk_buff		*skb;
711 	int			count = 0;
712 
713 	spin_lock_irqsave (&q->lock, flags);
714 	while (!skb_queue_empty(q)) {
715 		struct skb_data		*entry;
716 		struct urb		*urb;
717 		int			retval;
718 
719 		skb_queue_walk(q, skb) {
720 			entry = (struct skb_data *) skb->cb;
721 			if (entry->state != unlink_start)
722 				goto found;
723 		}
724 		break;
725 found:
726 		entry->state = unlink_start;
727 		urb = entry->urb;
728 
729 		/*
730 		 * Get reference count of the URB to avoid it to be
731 		 * freed during usb_unlink_urb, which may trigger
732 		 * use-after-free problem inside usb_unlink_urb since
733 		 * usb_unlink_urb is always racing with .complete
734 		 * handler(include defer_bh).
735 		 */
736 		usb_get_urb(urb);
737 		spin_unlock_irqrestore(&q->lock, flags);
738 		// during some PM-driven resume scenarios,
739 		// these (async) unlinks complete immediately
740 		retval = usb_unlink_urb (urb);
741 		if (retval != -EINPROGRESS && retval != 0)
742 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
743 		else
744 			count++;
745 		usb_put_urb(urb);
746 		spin_lock_irqsave(&q->lock, flags);
747 	}
748 	spin_unlock_irqrestore (&q->lock, flags);
749 	return count;
750 }
751 
752 // Flush all pending rx urbs
753 // minidrivers may need to do this when the MTU changes
754 
755 void usbnet_unlink_rx_urbs(struct usbnet *dev)
756 {
757 	if (netif_running(dev->net)) {
758 		(void) unlink_urbs (dev, &dev->rxq);
759 		tasklet_schedule(&dev->bh);
760 	}
761 }
762 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
763 
764 /*-------------------------------------------------------------------------*/
765 
766 static void wait_skb_queue_empty(struct sk_buff_head *q)
767 {
768 	unsigned long flags;
769 
770 	spin_lock_irqsave(&q->lock, flags);
771 	while (!skb_queue_empty(q)) {
772 		spin_unlock_irqrestore(&q->lock, flags);
773 		schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
774 		set_current_state(TASK_UNINTERRUPTIBLE);
775 		spin_lock_irqsave(&q->lock, flags);
776 	}
777 	spin_unlock_irqrestore(&q->lock, flags);
778 }
779 
780 // precondition: never called in_interrupt
781 static void usbnet_terminate_urbs(struct usbnet *dev)
782 {
783 	DECLARE_WAITQUEUE(wait, current);
784 	int temp;
785 
786 	/* ensure there are no more active urbs */
787 	add_wait_queue(&dev->wait, &wait);
788 	set_current_state(TASK_UNINTERRUPTIBLE);
789 	temp = unlink_urbs(dev, &dev->txq) +
790 		unlink_urbs(dev, &dev->rxq);
791 
792 	/* maybe wait for deletions to finish. */
793 	wait_skb_queue_empty(&dev->rxq);
794 	wait_skb_queue_empty(&dev->txq);
795 	wait_skb_queue_empty(&dev->done);
796 	netif_dbg(dev, ifdown, dev->net,
797 		  "waited for %d urb completions\n", temp);
798 	set_current_state(TASK_RUNNING);
799 	remove_wait_queue(&dev->wait, &wait);
800 }
801 
802 int usbnet_stop (struct net_device *net)
803 {
804 	struct usbnet		*dev = netdev_priv(net);
805 	struct driver_info	*info = dev->driver_info;
806 	int			retval, pm, mpn;
807 
808 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
809 	netif_stop_queue (net);
810 
811 	netif_info(dev, ifdown, dev->net,
812 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
813 		   net->stats.rx_packets, net->stats.tx_packets,
814 		   net->stats.rx_errors, net->stats.tx_errors);
815 
816 	/* to not race resume */
817 	pm = usb_autopm_get_interface(dev->intf);
818 	/* allow minidriver to stop correctly (wireless devices to turn off
819 	 * radio etc) */
820 	if (info->stop) {
821 		retval = info->stop(dev);
822 		if (retval < 0)
823 			netif_info(dev, ifdown, dev->net,
824 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
825 				   retval,
826 				   dev->udev->bus->bus_name, dev->udev->devpath,
827 				   info->description);
828 	}
829 
830 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
831 		usbnet_terminate_urbs(dev);
832 
833 	usbnet_status_stop(dev);
834 
835 	usbnet_purge_paused_rxq(dev);
836 
837 	mpn = !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
838 
839 	/* deferred work (task, timer, softirq) must also stop.
840 	 * can't flush_scheduled_work() until we drop rtnl (later),
841 	 * else workers could deadlock; so make workers a NOP.
842 	 */
843 	dev->flags = 0;
844 	del_timer_sync (&dev->delay);
845 	tasklet_kill (&dev->bh);
846 	if (!pm)
847 		usb_autopm_put_interface(dev->intf);
848 
849 	if (info->manage_power && mpn)
850 		info->manage_power(dev, 0);
851 	else
852 		usb_autopm_put_interface(dev->intf);
853 
854 	return 0;
855 }
856 EXPORT_SYMBOL_GPL(usbnet_stop);
857 
858 /*-------------------------------------------------------------------------*/
859 
860 // posts reads, and enables write queuing
861 
862 // precondition: never called in_interrupt
863 
864 int usbnet_open (struct net_device *net)
865 {
866 	struct usbnet		*dev = netdev_priv(net);
867 	int			retval;
868 	struct driver_info	*info = dev->driver_info;
869 
870 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
871 		netif_info(dev, ifup, dev->net,
872 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
873 			   retval,
874 			   dev->udev->bus->bus_name,
875 			   dev->udev->devpath,
876 			   info->description);
877 		goto done_nopm;
878 	}
879 
880 	// put into "known safe" state
881 	if (info->reset && (retval = info->reset (dev)) < 0) {
882 		netif_info(dev, ifup, dev->net,
883 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
884 			   retval,
885 			   dev->udev->bus->bus_name,
886 			   dev->udev->devpath,
887 			   info->description);
888 		goto done;
889 	}
890 
891 	/* hard_mtu or rx_urb_size may change in reset() */
892 	usbnet_update_max_qlen(dev);
893 
894 	// insist peer be connected
895 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
896 		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
897 		goto done;
898 	}
899 
900 	/* start any status interrupt transfer */
901 	if (dev->interrupt) {
902 		retval = usbnet_status_start(dev, GFP_KERNEL);
903 		if (retval < 0) {
904 			netif_err(dev, ifup, dev->net,
905 				  "intr submit %d\n", retval);
906 			goto done;
907 		}
908 	}
909 
910 	set_bit(EVENT_DEV_OPEN, &dev->flags);
911 	netif_start_queue (net);
912 	netif_info(dev, ifup, dev->net,
913 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
914 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
915 		   dev->net->mtu,
916 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
917 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
918 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
919 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
920 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
921 		   "simple");
922 
923 	/* reset rx error state */
924 	dev->pkt_cnt = 0;
925 	dev->pkt_err = 0;
926 	clear_bit(EVENT_RX_KILL, &dev->flags);
927 
928 	// delay posting reads until we're fully open
929 	tasklet_schedule (&dev->bh);
930 	if (info->manage_power) {
931 		retval = info->manage_power(dev, 1);
932 		if (retval < 0) {
933 			retval = 0;
934 			set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
935 		} else {
936 			usb_autopm_put_interface(dev->intf);
937 		}
938 	}
939 	return retval;
940 done:
941 	usb_autopm_put_interface(dev->intf);
942 done_nopm:
943 	return retval;
944 }
945 EXPORT_SYMBOL_GPL(usbnet_open);
946 
947 /*-------------------------------------------------------------------------*/
948 
949 /* ethtool methods; minidrivers may need to add some more, but
950  * they'll probably want to use this base set.
951  */
952 
953 int usbnet_get_link_ksettings(struct net_device *net,
954 			      struct ethtool_link_ksettings *cmd)
955 {
956 	struct usbnet *dev = netdev_priv(net);
957 
958 	if (!dev->mii.mdio_read)
959 		return -EOPNOTSUPP;
960 
961 	mii_ethtool_get_link_ksettings(&dev->mii, cmd);
962 
963 	return 0;
964 }
965 EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings);
966 
967 int usbnet_set_link_ksettings(struct net_device *net,
968 			      const struct ethtool_link_ksettings *cmd)
969 {
970 	struct usbnet *dev = netdev_priv(net);
971 	int retval;
972 
973 	if (!dev->mii.mdio_write)
974 		return -EOPNOTSUPP;
975 
976 	retval = mii_ethtool_set_link_ksettings(&dev->mii, cmd);
977 
978 	/* link speed/duplex might have changed */
979 	if (dev->driver_info->link_reset)
980 		dev->driver_info->link_reset(dev);
981 
982 	/* hard_mtu or rx_urb_size may change in link_reset() */
983 	usbnet_update_max_qlen(dev);
984 
985 	return retval;
986 }
987 EXPORT_SYMBOL_GPL(usbnet_set_link_ksettings);
988 
989 void usbnet_get_stats64(struct net_device *net, struct rtnl_link_stats64 *stats)
990 {
991 	struct usbnet *dev = netdev_priv(net);
992 	unsigned int start;
993 	int cpu;
994 
995 	netdev_stats_to_stats64(stats, &net->stats);
996 
997 	for_each_possible_cpu(cpu) {
998 		struct pcpu_sw_netstats *stats64;
999 		u64 rx_packets, rx_bytes;
1000 		u64 tx_packets, tx_bytes;
1001 
1002 		stats64 = per_cpu_ptr(dev->stats64, cpu);
1003 
1004 		do {
1005 			start = u64_stats_fetch_begin_irq(&stats64->syncp);
1006 			rx_packets = stats64->rx_packets;
1007 			rx_bytes = stats64->rx_bytes;
1008 			tx_packets = stats64->tx_packets;
1009 			tx_bytes = stats64->tx_bytes;
1010 		} while (u64_stats_fetch_retry_irq(&stats64->syncp, start));
1011 
1012 		stats->rx_packets += rx_packets;
1013 		stats->rx_bytes += rx_bytes;
1014 		stats->tx_packets += tx_packets;
1015 		stats->tx_bytes += tx_bytes;
1016 	}
1017 }
1018 EXPORT_SYMBOL_GPL(usbnet_get_stats64);
1019 
1020 u32 usbnet_get_link (struct net_device *net)
1021 {
1022 	struct usbnet *dev = netdev_priv(net);
1023 
1024 	/* If a check_connect is defined, return its result */
1025 	if (dev->driver_info->check_connect)
1026 		return dev->driver_info->check_connect (dev) == 0;
1027 
1028 	/* if the device has mii operations, use those */
1029 	if (dev->mii.mdio_read)
1030 		return mii_link_ok(&dev->mii);
1031 
1032 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
1033 	return ethtool_op_get_link(net);
1034 }
1035 EXPORT_SYMBOL_GPL(usbnet_get_link);
1036 
1037 int usbnet_nway_reset(struct net_device *net)
1038 {
1039 	struct usbnet *dev = netdev_priv(net);
1040 
1041 	if (!dev->mii.mdio_write)
1042 		return -EOPNOTSUPP;
1043 
1044 	return mii_nway_restart(&dev->mii);
1045 }
1046 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
1047 
1048 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
1049 {
1050 	struct usbnet *dev = netdev_priv(net);
1051 
1052 	strlcpy (info->driver, dev->driver_name, sizeof info->driver);
1053 	strlcpy (info->version, DRIVER_VERSION, sizeof info->version);
1054 	strlcpy (info->fw_version, dev->driver_info->description,
1055 		sizeof info->fw_version);
1056 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
1057 }
1058 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
1059 
1060 u32 usbnet_get_msglevel (struct net_device *net)
1061 {
1062 	struct usbnet *dev = netdev_priv(net);
1063 
1064 	return dev->msg_enable;
1065 }
1066 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
1067 
1068 void usbnet_set_msglevel (struct net_device *net, u32 level)
1069 {
1070 	struct usbnet *dev = netdev_priv(net);
1071 
1072 	dev->msg_enable = level;
1073 }
1074 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
1075 
1076 /* drivers may override default ethtool_ops in their bind() routine */
1077 static const struct ethtool_ops usbnet_ethtool_ops = {
1078 	.get_link		= usbnet_get_link,
1079 	.nway_reset		= usbnet_nway_reset,
1080 	.get_drvinfo		= usbnet_get_drvinfo,
1081 	.get_msglevel		= usbnet_get_msglevel,
1082 	.set_msglevel		= usbnet_set_msglevel,
1083 	.get_ts_info		= ethtool_op_get_ts_info,
1084 	.get_link_ksettings	= usbnet_get_link_ksettings,
1085 	.set_link_ksettings	= usbnet_set_link_ksettings,
1086 };
1087 
1088 /*-------------------------------------------------------------------------*/
1089 
1090 static void __handle_link_change(struct usbnet *dev)
1091 {
1092 	if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
1093 		return;
1094 
1095 	if (!netif_carrier_ok(dev->net)) {
1096 		/* kill URBs for reading packets to save bus bandwidth */
1097 		unlink_urbs(dev, &dev->rxq);
1098 
1099 		/*
1100 		 * tx_timeout will unlink URBs for sending packets and
1101 		 * tx queue is stopped by netcore after link becomes off
1102 		 */
1103 	} else {
1104 		/* submitting URBs for reading packets */
1105 		tasklet_schedule(&dev->bh);
1106 	}
1107 
1108 	/* hard_mtu or rx_urb_size may change during link change */
1109 	usbnet_update_max_qlen(dev);
1110 
1111 	clear_bit(EVENT_LINK_CHANGE, &dev->flags);
1112 }
1113 
1114 static void usbnet_set_rx_mode(struct net_device *net)
1115 {
1116 	struct usbnet		*dev = netdev_priv(net);
1117 
1118 	usbnet_defer_kevent(dev, EVENT_SET_RX_MODE);
1119 }
1120 
1121 static void __handle_set_rx_mode(struct usbnet *dev)
1122 {
1123 	if (dev->driver_info->set_rx_mode)
1124 		(dev->driver_info->set_rx_mode)(dev);
1125 
1126 	clear_bit(EVENT_SET_RX_MODE, &dev->flags);
1127 }
1128 
1129 /* work that cannot be done in interrupt context uses keventd.
1130  *
1131  * NOTE:  with 2.5 we could do more of this using completion callbacks,
1132  * especially now that control transfers can be queued.
1133  */
1134 static void
1135 usbnet_deferred_kevent (struct work_struct *work)
1136 {
1137 	struct usbnet		*dev =
1138 		container_of(work, struct usbnet, kevent);
1139 	int			status;
1140 
1141 	/* usb_clear_halt() needs a thread context */
1142 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
1143 		unlink_urbs (dev, &dev->txq);
1144 		status = usb_autopm_get_interface(dev->intf);
1145 		if (status < 0)
1146 			goto fail_pipe;
1147 		status = usb_clear_halt (dev->udev, dev->out);
1148 		usb_autopm_put_interface(dev->intf);
1149 		if (status < 0 &&
1150 		    status != -EPIPE &&
1151 		    status != -ESHUTDOWN) {
1152 			if (netif_msg_tx_err (dev))
1153 fail_pipe:
1154 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
1155 					   status);
1156 		} else {
1157 			clear_bit (EVENT_TX_HALT, &dev->flags);
1158 			if (status != -ESHUTDOWN)
1159 				netif_wake_queue (dev->net);
1160 		}
1161 	}
1162 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
1163 		unlink_urbs (dev, &dev->rxq);
1164 		status = usb_autopm_get_interface(dev->intf);
1165 		if (status < 0)
1166 			goto fail_halt;
1167 		status = usb_clear_halt (dev->udev, dev->in);
1168 		usb_autopm_put_interface(dev->intf);
1169 		if (status < 0 &&
1170 		    status != -EPIPE &&
1171 		    status != -ESHUTDOWN) {
1172 			if (netif_msg_rx_err (dev))
1173 fail_halt:
1174 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
1175 					   status);
1176 		} else {
1177 			clear_bit (EVENT_RX_HALT, &dev->flags);
1178 			tasklet_schedule (&dev->bh);
1179 		}
1180 	}
1181 
1182 	/* tasklet could resubmit itself forever if memory is tight */
1183 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
1184 		struct urb	*urb = NULL;
1185 		int resched = 1;
1186 
1187 		if (netif_running (dev->net))
1188 			urb = usb_alloc_urb (0, GFP_KERNEL);
1189 		else
1190 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1191 		if (urb != NULL) {
1192 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1193 			status = usb_autopm_get_interface(dev->intf);
1194 			if (status < 0) {
1195 				usb_free_urb(urb);
1196 				goto fail_lowmem;
1197 			}
1198 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
1199 				resched = 0;
1200 			usb_autopm_put_interface(dev->intf);
1201 fail_lowmem:
1202 			if (resched)
1203 				tasklet_schedule (&dev->bh);
1204 		}
1205 	}
1206 
1207 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
1208 		struct driver_info	*info = dev->driver_info;
1209 		int			retval = 0;
1210 
1211 		clear_bit (EVENT_LINK_RESET, &dev->flags);
1212 		status = usb_autopm_get_interface(dev->intf);
1213 		if (status < 0)
1214 			goto skip_reset;
1215 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1216 			usb_autopm_put_interface(dev->intf);
1217 skip_reset:
1218 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1219 				    retval,
1220 				    dev->udev->bus->bus_name,
1221 				    dev->udev->devpath,
1222 				    info->description);
1223 		} else {
1224 			usb_autopm_put_interface(dev->intf);
1225 		}
1226 
1227 		/* handle link change from link resetting */
1228 		__handle_link_change(dev);
1229 	}
1230 
1231 	if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
1232 		__handle_link_change(dev);
1233 
1234 	if (test_bit (EVENT_SET_RX_MODE, &dev->flags))
1235 		__handle_set_rx_mode(dev);
1236 
1237 
1238 	if (dev->flags)
1239 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1240 }
1241 
1242 /*-------------------------------------------------------------------------*/
1243 
1244 static void tx_complete (struct urb *urb)
1245 {
1246 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1247 	struct skb_data		*entry = (struct skb_data *) skb->cb;
1248 	struct usbnet		*dev = entry->dev;
1249 
1250 	if (urb->status == 0) {
1251 		struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->stats64);
1252 		unsigned long flags;
1253 
1254 		flags = u64_stats_update_begin_irqsave(&stats64->syncp);
1255 		stats64->tx_packets += entry->packets;
1256 		stats64->tx_bytes += entry->length;
1257 		u64_stats_update_end_irqrestore(&stats64->syncp, flags);
1258 	} else {
1259 		dev->net->stats.tx_errors++;
1260 
1261 		switch (urb->status) {
1262 		case -EPIPE:
1263 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1264 			break;
1265 
1266 		/* software-driven interface shutdown */
1267 		case -ECONNRESET:		// async unlink
1268 		case -ESHUTDOWN:		// hardware gone
1269 			break;
1270 
1271 		/* like rx, tx gets controller i/o faults during hub_wq
1272 		 * delays and so it uses the same throttling mechanism.
1273 		 */
1274 		case -EPROTO:
1275 		case -ETIME:
1276 		case -EILSEQ:
1277 			usb_mark_last_busy(dev->udev);
1278 			if (!timer_pending (&dev->delay)) {
1279 				mod_timer (&dev->delay,
1280 					jiffies + THROTTLE_JIFFIES);
1281 				netif_dbg(dev, link, dev->net,
1282 					  "tx throttle %d\n", urb->status);
1283 			}
1284 			netif_stop_queue (dev->net);
1285 			break;
1286 		default:
1287 			netif_dbg(dev, tx_err, dev->net,
1288 				  "tx err %d\n", entry->urb->status);
1289 			break;
1290 		}
1291 	}
1292 
1293 	usb_autopm_put_interface_async(dev->intf);
1294 	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1295 }
1296 
1297 /*-------------------------------------------------------------------------*/
1298 
1299 void usbnet_tx_timeout (struct net_device *net)
1300 {
1301 	struct usbnet		*dev = netdev_priv(net);
1302 
1303 	unlink_urbs (dev, &dev->txq);
1304 	tasklet_schedule (&dev->bh);
1305 	/* this needs to be handled individually because the generic layer
1306 	 * doesn't know what is sufficient and could not restore private
1307 	 * information if a remedy of an unconditional reset were used.
1308 	 */
1309 	if (dev->driver_info->recover)
1310 		(dev->driver_info->recover)(dev);
1311 }
1312 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1313 
1314 /*-------------------------------------------------------------------------*/
1315 
1316 static int build_dma_sg(const struct sk_buff *skb, struct urb *urb)
1317 {
1318 	unsigned num_sgs, total_len = 0;
1319 	int i, s = 0;
1320 
1321 	num_sgs = skb_shinfo(skb)->nr_frags + 1;
1322 	if (num_sgs == 1)
1323 		return 0;
1324 
1325 	/* reserve one for zero packet */
1326 	urb->sg = kmalloc((num_sgs + 1) * sizeof(struct scatterlist),
1327 			  GFP_ATOMIC);
1328 	if (!urb->sg)
1329 		return -ENOMEM;
1330 
1331 	urb->num_sgs = num_sgs;
1332 	sg_init_table(urb->sg, urb->num_sgs + 1);
1333 
1334 	sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb));
1335 	total_len += skb_headlen(skb);
1336 
1337 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1338 		struct skb_frag_struct *f = &skb_shinfo(skb)->frags[i];
1339 
1340 		total_len += skb_frag_size(f);
1341 		sg_set_page(&urb->sg[i + s], f->page.p, f->size,
1342 				f->page_offset);
1343 	}
1344 	urb->transfer_buffer_length = total_len;
1345 
1346 	return 1;
1347 }
1348 
1349 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1350 				     struct net_device *net)
1351 {
1352 	struct usbnet		*dev = netdev_priv(net);
1353 	unsigned int			length;
1354 	struct urb		*urb = NULL;
1355 	struct skb_data		*entry;
1356 	struct driver_info	*info = dev->driver_info;
1357 	unsigned long		flags;
1358 	int retval;
1359 
1360 	if (skb)
1361 		skb_tx_timestamp(skb);
1362 
1363 	// some devices want funky USB-level framing, for
1364 	// win32 driver (usually) and/or hardware quirks
1365 	if (info->tx_fixup) {
1366 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1367 		if (!skb) {
1368 			/* packet collected; minidriver waiting for more */
1369 			if (info->flags & FLAG_MULTI_PACKET)
1370 				goto not_drop;
1371 			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1372 			goto drop;
1373 		}
1374 	}
1375 
1376 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1377 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1378 		goto drop;
1379 	}
1380 
1381 	entry = (struct skb_data *) skb->cb;
1382 	entry->urb = urb;
1383 	entry->dev = dev;
1384 
1385 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1386 			skb->data, skb->len, tx_complete, skb);
1387 	if (dev->can_dma_sg) {
1388 		if (build_dma_sg(skb, urb) < 0)
1389 			goto drop;
1390 	}
1391 	length = urb->transfer_buffer_length;
1392 
1393 	/* don't assume the hardware handles USB_ZERO_PACKET
1394 	 * NOTE:  strictly conforming cdc-ether devices should expect
1395 	 * the ZLP here, but ignore the one-byte packet.
1396 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1397 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1398 	 * packet itself if needed.
1399 	 */
1400 	if (length % dev->maxpacket == 0) {
1401 		if (!(info->flags & FLAG_SEND_ZLP)) {
1402 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1403 				length++;
1404 				if (skb_tailroom(skb) && !urb->num_sgs) {
1405 					skb->data[skb->len] = 0;
1406 					__skb_put(skb, 1);
1407 				} else if (urb->num_sgs)
1408 					sg_set_buf(&urb->sg[urb->num_sgs++],
1409 							dev->padding_pkt, 1);
1410 			}
1411 		} else
1412 			urb->transfer_flags |= URB_ZERO_PACKET;
1413 	}
1414 	urb->transfer_buffer_length = length;
1415 
1416 	if (info->flags & FLAG_MULTI_PACKET) {
1417 		/* Driver has set number of packets and a length delta.
1418 		 * Calculate the complete length and ensure that it's
1419 		 * positive.
1420 		 */
1421 		entry->length += length;
1422 		if (WARN_ON_ONCE(entry->length <= 0))
1423 			entry->length = length;
1424 	} else {
1425 		usbnet_set_skb_tx_stats(skb, 1, length);
1426 	}
1427 
1428 	spin_lock_irqsave(&dev->txq.lock, flags);
1429 	retval = usb_autopm_get_interface_async(dev->intf);
1430 	if (retval < 0) {
1431 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1432 		goto drop;
1433 	}
1434 
1435 #ifdef CONFIG_PM
1436 	/* if this triggers the device is still a sleep */
1437 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1438 		/* transmission will be done in resume */
1439 		usb_anchor_urb(urb, &dev->deferred);
1440 		/* no use to process more packets */
1441 		netif_stop_queue(net);
1442 		usb_put_urb(urb);
1443 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1444 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1445 		goto deferred;
1446 	}
1447 #endif
1448 
1449 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1450 	case -EPIPE:
1451 		netif_stop_queue (net);
1452 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1453 		usb_autopm_put_interface_async(dev->intf);
1454 		break;
1455 	default:
1456 		usb_autopm_put_interface_async(dev->intf);
1457 		netif_dbg(dev, tx_err, dev->net,
1458 			  "tx: submit urb err %d\n", retval);
1459 		break;
1460 	case 0:
1461 		netif_trans_update(net);
1462 		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1463 		if (dev->txq.qlen >= TX_QLEN (dev))
1464 			netif_stop_queue (net);
1465 	}
1466 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1467 
1468 	if (retval) {
1469 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1470 drop:
1471 		dev->net->stats.tx_dropped++;
1472 not_drop:
1473 		if (skb)
1474 			dev_kfree_skb_any (skb);
1475 		if (urb) {
1476 			kfree(urb->sg);
1477 			usb_free_urb(urb);
1478 		}
1479 	} else
1480 		netif_dbg(dev, tx_queued, dev->net,
1481 			  "> tx, len %u, type 0x%x\n", length, skb->protocol);
1482 #ifdef CONFIG_PM
1483 deferred:
1484 #endif
1485 	return NETDEV_TX_OK;
1486 }
1487 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1488 
1489 static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1490 {
1491 	struct urb	*urb;
1492 	int		i;
1493 	int		ret = 0;
1494 
1495 	/* don't refill the queue all at once */
1496 	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1497 		urb = usb_alloc_urb(0, flags);
1498 		if (urb != NULL) {
1499 			ret = rx_submit(dev, urb, flags);
1500 			if (ret)
1501 				goto err;
1502 		} else {
1503 			ret = -ENOMEM;
1504 			goto err;
1505 		}
1506 	}
1507 err:
1508 	return ret;
1509 }
1510 
1511 /*-------------------------------------------------------------------------*/
1512 
1513 // tasklet (work deferred from completions, in_irq) or timer
1514 
1515 static void usbnet_bh (struct timer_list *t)
1516 {
1517 	struct usbnet		*dev = from_timer(dev, t, delay);
1518 	struct sk_buff		*skb;
1519 	struct skb_data		*entry;
1520 
1521 	while ((skb = skb_dequeue (&dev->done))) {
1522 		entry = (struct skb_data *) skb->cb;
1523 		switch (entry->state) {
1524 		case rx_done:
1525 			entry->state = rx_cleanup;
1526 			rx_process (dev, skb);
1527 			continue;
1528 		case tx_done:
1529 			kfree(entry->urb->sg);
1530 		case rx_cleanup:
1531 			usb_free_urb (entry->urb);
1532 			dev_kfree_skb (skb);
1533 			continue;
1534 		default:
1535 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1536 		}
1537 	}
1538 
1539 	/* restart RX again after disabling due to high error rate */
1540 	clear_bit(EVENT_RX_KILL, &dev->flags);
1541 
1542 	/* waiting for all pending urbs to complete?
1543 	 * only then can we forgo submitting anew
1544 	 */
1545 	if (waitqueue_active(&dev->wait)) {
1546 		if (dev->txq.qlen + dev->rxq.qlen + dev->done.qlen == 0)
1547 			wake_up_all(&dev->wait);
1548 
1549 	// or are we maybe short a few urbs?
1550 	} else if (netif_running (dev->net) &&
1551 		   netif_device_present (dev->net) &&
1552 		   netif_carrier_ok(dev->net) &&
1553 		   !timer_pending(&dev->delay) &&
1554 		   !test_bit(EVENT_RX_PAUSED, &dev->flags) &&
1555 		   !test_bit(EVENT_RX_HALT, &dev->flags)) {
1556 		int	temp = dev->rxq.qlen;
1557 
1558 		if (temp < RX_QLEN(dev)) {
1559 			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1560 				return;
1561 			if (temp != dev->rxq.qlen)
1562 				netif_dbg(dev, link, dev->net,
1563 					  "rxqlen %d --> %d\n",
1564 					  temp, dev->rxq.qlen);
1565 			if (dev->rxq.qlen < RX_QLEN(dev))
1566 				tasklet_schedule (&dev->bh);
1567 		}
1568 		if (dev->txq.qlen < TX_QLEN (dev))
1569 			netif_wake_queue (dev->net);
1570 	}
1571 }
1572 
1573 
1574 /*-------------------------------------------------------------------------
1575  *
1576  * USB Device Driver support
1577  *
1578  *-------------------------------------------------------------------------*/
1579 
1580 // precondition: never called in_interrupt
1581 
1582 void usbnet_disconnect (struct usb_interface *intf)
1583 {
1584 	struct usbnet		*dev;
1585 	struct usb_device	*xdev;
1586 	struct net_device	*net;
1587 
1588 	dev = usb_get_intfdata(intf);
1589 	usb_set_intfdata(intf, NULL);
1590 	if (!dev)
1591 		return;
1592 
1593 	xdev = interface_to_usbdev (intf);
1594 
1595 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1596 		   intf->dev.driver->name,
1597 		   xdev->bus->bus_name, xdev->devpath,
1598 		   dev->driver_info->description);
1599 
1600 	net = dev->net;
1601 	unregister_netdev (net);
1602 
1603 	cancel_work_sync(&dev->kevent);
1604 
1605 	usb_scuttle_anchored_urbs(&dev->deferred);
1606 
1607 	if (dev->driver_info->unbind)
1608 		dev->driver_info->unbind (dev, intf);
1609 
1610 	usb_kill_urb(dev->interrupt);
1611 	usb_free_urb(dev->interrupt);
1612 	kfree(dev->padding_pkt);
1613 
1614 	free_percpu(dev->stats64);
1615 	free_netdev(net);
1616 }
1617 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1618 
1619 static const struct net_device_ops usbnet_netdev_ops = {
1620 	.ndo_open		= usbnet_open,
1621 	.ndo_stop		= usbnet_stop,
1622 	.ndo_start_xmit		= usbnet_start_xmit,
1623 	.ndo_tx_timeout		= usbnet_tx_timeout,
1624 	.ndo_set_rx_mode	= usbnet_set_rx_mode,
1625 	.ndo_change_mtu		= usbnet_change_mtu,
1626 	.ndo_get_stats64	= usbnet_get_stats64,
1627 	.ndo_set_mac_address 	= eth_mac_addr,
1628 	.ndo_validate_addr	= eth_validate_addr,
1629 };
1630 
1631 /*-------------------------------------------------------------------------*/
1632 
1633 // precondition: never called in_interrupt
1634 
1635 static struct device_type wlan_type = {
1636 	.name	= "wlan",
1637 };
1638 
1639 static struct device_type wwan_type = {
1640 	.name	= "wwan",
1641 };
1642 
1643 int
1644 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1645 {
1646 	struct usbnet			*dev;
1647 	struct net_device		*net;
1648 	struct usb_host_interface	*interface;
1649 	struct driver_info		*info;
1650 	struct usb_device		*xdev;
1651 	int				status;
1652 	const char			*name;
1653 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1654 
1655 	/* usbnet already took usb runtime pm, so have to enable the feature
1656 	 * for usb interface, otherwise usb_autopm_get_interface may return
1657 	 * failure if RUNTIME_PM is enabled.
1658 	 */
1659 	if (!driver->supports_autosuspend) {
1660 		driver->supports_autosuspend = 1;
1661 		pm_runtime_enable(&udev->dev);
1662 	}
1663 
1664 	name = udev->dev.driver->name;
1665 	info = (struct driver_info *) prod->driver_info;
1666 	if (!info) {
1667 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1668 		return -ENODEV;
1669 	}
1670 	xdev = interface_to_usbdev (udev);
1671 	interface = udev->cur_altsetting;
1672 
1673 	status = -ENOMEM;
1674 
1675 	// set up our own records
1676 	net = alloc_etherdev(sizeof(*dev));
1677 	if (!net)
1678 		goto out;
1679 
1680 	/* netdev_printk() needs this so do it as early as possible */
1681 	SET_NETDEV_DEV(net, &udev->dev);
1682 
1683 	dev = netdev_priv(net);
1684 	dev->udev = xdev;
1685 	dev->intf = udev;
1686 	dev->driver_info = info;
1687 	dev->driver_name = name;
1688 
1689 	dev->stats64 = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1690 	if (!dev->stats64)
1691 		goto out0;
1692 
1693 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1694 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1695 	init_waitqueue_head(&dev->wait);
1696 	skb_queue_head_init (&dev->rxq);
1697 	skb_queue_head_init (&dev->txq);
1698 	skb_queue_head_init (&dev->done);
1699 	skb_queue_head_init(&dev->rxq_pause);
1700 	dev->bh.func = (void (*)(unsigned long))usbnet_bh;
1701 	dev->bh.data = (unsigned long)&dev->delay;
1702 	INIT_WORK (&dev->kevent, usbnet_deferred_kevent);
1703 	init_usb_anchor(&dev->deferred);
1704 	timer_setup(&dev->delay, usbnet_bh, 0);
1705 	mutex_init (&dev->phy_mutex);
1706 	mutex_init(&dev->interrupt_mutex);
1707 	dev->interrupt_count = 0;
1708 
1709 	dev->net = net;
1710 	strcpy (net->name, "usb%d");
1711 	memcpy (net->dev_addr, node_id, sizeof node_id);
1712 
1713 	/* rx and tx sides can use different message sizes;
1714 	 * bind() should set rx_urb_size in that case.
1715 	 */
1716 	dev->hard_mtu = net->mtu + net->hard_header_len;
1717 	net->min_mtu = 0;
1718 	net->max_mtu = ETH_MAX_MTU;
1719 
1720 	net->netdev_ops = &usbnet_netdev_ops;
1721 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1722 	net->ethtool_ops = &usbnet_ethtool_ops;
1723 
1724 	// allow device-specific bind/init procedures
1725 	// NOTE net->name still not usable ...
1726 	if (info->bind) {
1727 		status = info->bind (dev, udev);
1728 		if (status < 0)
1729 			goto out1;
1730 
1731 		// heuristic:  "usb%d" for links we know are two-host,
1732 		// else "eth%d" when there's reasonable doubt.  userspace
1733 		// can rename the link if it knows better.
1734 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1735 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1736 		     (net->dev_addr [0] & 0x02) == 0))
1737 			strcpy (net->name, "eth%d");
1738 		/* WLAN devices should always be named "wlan%d" */
1739 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1740 			strcpy(net->name, "wlan%d");
1741 		/* WWAN devices should always be named "wwan%d" */
1742 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1743 			strcpy(net->name, "wwan%d");
1744 
1745 		/* devices that cannot do ARP */
1746 		if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1747 			net->flags |= IFF_NOARP;
1748 
1749 		/* maybe the remote can't receive an Ethernet MTU */
1750 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1751 			net->mtu = dev->hard_mtu - net->hard_header_len;
1752 	} else if (!info->in || !info->out)
1753 		status = usbnet_get_endpoints (dev, udev);
1754 	else {
1755 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1756 		dev->out = usb_sndbulkpipe (xdev, info->out);
1757 		if (!(info->flags & FLAG_NO_SETINT))
1758 			status = usb_set_interface (xdev,
1759 				interface->desc.bInterfaceNumber,
1760 				interface->desc.bAlternateSetting);
1761 		else
1762 			status = 0;
1763 
1764 	}
1765 	if (status >= 0 && dev->status)
1766 		status = init_status (dev, udev);
1767 	if (status < 0)
1768 		goto out3;
1769 
1770 	if (!dev->rx_urb_size)
1771 		dev->rx_urb_size = dev->hard_mtu;
1772 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1773 
1774 	/* let userspace know we have a random address */
1775 	if (ether_addr_equal(net->dev_addr, node_id))
1776 		net->addr_assign_type = NET_ADDR_RANDOM;
1777 
1778 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1779 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1780 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1781 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1782 
1783 	/* initialize max rx_qlen and tx_qlen */
1784 	usbnet_update_max_qlen(dev);
1785 
1786 	if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&
1787 		!(info->flags & FLAG_MULTI_PACKET)) {
1788 		dev->padding_pkt = kzalloc(1, GFP_KERNEL);
1789 		if (!dev->padding_pkt) {
1790 			status = -ENOMEM;
1791 			goto out4;
1792 		}
1793 	}
1794 
1795 	status = register_netdev (net);
1796 	if (status)
1797 		goto out5;
1798 	netif_info(dev, probe, dev->net,
1799 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1800 		   udev->dev.driver->name,
1801 		   xdev->bus->bus_name, xdev->devpath,
1802 		   dev->driver_info->description,
1803 		   net->dev_addr);
1804 
1805 	// ok, it's ready to go.
1806 	usb_set_intfdata (udev, dev);
1807 
1808 	netif_device_attach (net);
1809 
1810 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1811 		usbnet_link_change(dev, 0, 0);
1812 
1813 	return 0;
1814 
1815 out5:
1816 	kfree(dev->padding_pkt);
1817 out4:
1818 	usb_free_urb(dev->interrupt);
1819 out3:
1820 	if (info->unbind)
1821 		info->unbind (dev, udev);
1822 out1:
1823 	/* subdrivers must undo all they did in bind() if they
1824 	 * fail it, but we may fail later and a deferred kevent
1825 	 * may trigger an error resubmitting itself and, worse,
1826 	 * schedule a timer. So we kill it all just in case.
1827 	 */
1828 	cancel_work_sync(&dev->kevent);
1829 	del_timer_sync(&dev->delay);
1830 	free_percpu(dev->stats64);
1831 out0:
1832 	free_netdev(net);
1833 out:
1834 	return status;
1835 }
1836 EXPORT_SYMBOL_GPL(usbnet_probe);
1837 
1838 /*-------------------------------------------------------------------------*/
1839 
1840 /*
1841  * suspend the whole driver as soon as the first interface is suspended
1842  * resume only when the last interface is resumed
1843  */
1844 
1845 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1846 {
1847 	struct usbnet		*dev = usb_get_intfdata(intf);
1848 
1849 	if (!dev->suspend_count++) {
1850 		spin_lock_irq(&dev->txq.lock);
1851 		/* don't autosuspend while transmitting */
1852 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1853 			dev->suspend_count--;
1854 			spin_unlock_irq(&dev->txq.lock);
1855 			return -EBUSY;
1856 		} else {
1857 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1858 			spin_unlock_irq(&dev->txq.lock);
1859 		}
1860 		/*
1861 		 * accelerate emptying of the rx and queues, to avoid
1862 		 * having everything error out.
1863 		 */
1864 		netif_device_detach (dev->net);
1865 		usbnet_terminate_urbs(dev);
1866 		__usbnet_status_stop_force(dev);
1867 
1868 		/*
1869 		 * reattach so runtime management can use and
1870 		 * wake the device
1871 		 */
1872 		netif_device_attach (dev->net);
1873 	}
1874 	return 0;
1875 }
1876 EXPORT_SYMBOL_GPL(usbnet_suspend);
1877 
1878 int usbnet_resume (struct usb_interface *intf)
1879 {
1880 	struct usbnet		*dev = usb_get_intfdata(intf);
1881 	struct sk_buff          *skb;
1882 	struct urb              *res;
1883 	int                     retval;
1884 
1885 	if (!--dev->suspend_count) {
1886 		/* resume interrupt URB if it was previously submitted */
1887 		__usbnet_status_start_force(dev, GFP_NOIO);
1888 
1889 		spin_lock_irq(&dev->txq.lock);
1890 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1891 
1892 			skb = (struct sk_buff *)res->context;
1893 			retval = usb_submit_urb(res, GFP_ATOMIC);
1894 			if (retval < 0) {
1895 				dev_kfree_skb_any(skb);
1896 				kfree(res->sg);
1897 				usb_free_urb(res);
1898 				usb_autopm_put_interface_async(dev->intf);
1899 			} else {
1900 				netif_trans_update(dev->net);
1901 				__skb_queue_tail(&dev->txq, skb);
1902 			}
1903 		}
1904 
1905 		smp_mb();
1906 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1907 		spin_unlock_irq(&dev->txq.lock);
1908 
1909 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1910 			/* handle remote wakeup ASAP
1911 			 * we cannot race against stop
1912 			 */
1913 			if (netif_device_present(dev->net) &&
1914 				!timer_pending(&dev->delay) &&
1915 				!test_bit(EVENT_RX_HALT, &dev->flags))
1916 					rx_alloc_submit(dev, GFP_NOIO);
1917 
1918 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1919 				netif_tx_wake_all_queues(dev->net);
1920 			tasklet_schedule (&dev->bh);
1921 		}
1922 	}
1923 
1924 	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1925 		usb_autopm_get_interface_no_resume(intf);
1926 
1927 	return 0;
1928 }
1929 EXPORT_SYMBOL_GPL(usbnet_resume);
1930 
1931 /*
1932  * Either a subdriver implements manage_power, then it is assumed to always
1933  * be ready to be suspended or it reports the readiness to be suspended
1934  * explicitly
1935  */
1936 void usbnet_device_suggests_idle(struct usbnet *dev)
1937 {
1938 	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1939 		dev->intf->needs_remote_wakeup = 1;
1940 		usb_autopm_put_interface_async(dev->intf);
1941 	}
1942 }
1943 EXPORT_SYMBOL(usbnet_device_suggests_idle);
1944 
1945 /*
1946  * For devices that can do without special commands
1947  */
1948 int usbnet_manage_power(struct usbnet *dev, int on)
1949 {
1950 	dev->intf->needs_remote_wakeup = on;
1951 	return 0;
1952 }
1953 EXPORT_SYMBOL(usbnet_manage_power);
1954 
1955 void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
1956 {
1957 	/* update link after link is reseted */
1958 	if (link && !need_reset)
1959 		netif_carrier_on(dev->net);
1960 	else
1961 		netif_carrier_off(dev->net);
1962 
1963 	if (need_reset && link)
1964 		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
1965 	else
1966 		usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
1967 }
1968 EXPORT_SYMBOL(usbnet_link_change);
1969 
1970 /*-------------------------------------------------------------------------*/
1971 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1972 			     u16 value, u16 index, void *data, u16 size)
1973 {
1974 	void *buf = NULL;
1975 	int err = -ENOMEM;
1976 
1977 	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
1978 		   " value=0x%04x index=0x%04x size=%d\n",
1979 		   cmd, reqtype, value, index, size);
1980 
1981 	if (size) {
1982 		buf = kmalloc(size, GFP_KERNEL);
1983 		if (!buf)
1984 			goto out;
1985 	}
1986 
1987 	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
1988 			      cmd, reqtype, value, index, buf, size,
1989 			      USB_CTRL_GET_TIMEOUT);
1990 	if (err > 0 && err <= size) {
1991         if (data)
1992             memcpy(data, buf, err);
1993         else
1994             netdev_dbg(dev->net,
1995                 "Huh? Data requested but thrown away.\n");
1996     }
1997 	kfree(buf);
1998 out:
1999 	return err;
2000 }
2001 
2002 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2003 			      u16 value, u16 index, const void *data,
2004 			      u16 size)
2005 {
2006 	void *buf = NULL;
2007 	int err = -ENOMEM;
2008 
2009 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2010 		   " value=0x%04x index=0x%04x size=%d\n",
2011 		   cmd, reqtype, value, index, size);
2012 
2013 	if (data) {
2014 		buf = kmemdup(data, size, GFP_KERNEL);
2015 		if (!buf)
2016 			goto out;
2017 	} else {
2018         if (size) {
2019             WARN_ON_ONCE(1);
2020             err = -EINVAL;
2021             goto out;
2022         }
2023     }
2024 
2025 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
2026 			      cmd, reqtype, value, index, buf, size,
2027 			      USB_CTRL_SET_TIMEOUT);
2028 	kfree(buf);
2029 
2030 out:
2031 	return err;
2032 }
2033 
2034 /*
2035  * The function can't be called inside suspend/resume callback,
2036  * otherwise deadlock will be caused.
2037  */
2038 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2039 		    u16 value, u16 index, void *data, u16 size)
2040 {
2041 	int ret;
2042 
2043 	if (usb_autopm_get_interface(dev->intf) < 0)
2044 		return -ENODEV;
2045 	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2046 				data, size);
2047 	usb_autopm_put_interface(dev->intf);
2048 	return ret;
2049 }
2050 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
2051 
2052 /*
2053  * The function can't be called inside suspend/resume callback,
2054  * otherwise deadlock will be caused.
2055  */
2056 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2057 		     u16 value, u16 index, const void *data, u16 size)
2058 {
2059 	int ret;
2060 
2061 	if (usb_autopm_get_interface(dev->intf) < 0)
2062 		return -ENODEV;
2063 	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2064 				 data, size);
2065 	usb_autopm_put_interface(dev->intf);
2066 	return ret;
2067 }
2068 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
2069 
2070 /*
2071  * The function can be called inside suspend/resume callback safely
2072  * and should only be called by suspend/resume callback generally.
2073  */
2074 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2075 			  u16 value, u16 index, void *data, u16 size)
2076 {
2077 	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2078 				 data, size);
2079 }
2080 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
2081 
2082 /*
2083  * The function can be called inside suspend/resume callback safely
2084  * and should only be called by suspend/resume callback generally.
2085  */
2086 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2087 			  u16 value, u16 index, const void *data,
2088 			  u16 size)
2089 {
2090 	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2091 				  data, size);
2092 }
2093 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
2094 
2095 static void usbnet_async_cmd_cb(struct urb *urb)
2096 {
2097 	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
2098 	int status = urb->status;
2099 
2100 	if (status < 0)
2101 		dev_dbg(&urb->dev->dev, "%s failed with %d",
2102 			__func__, status);
2103 
2104 	kfree(req);
2105 	usb_free_urb(urb);
2106 }
2107 
2108 /*
2109  * The caller must make sure that device can't be put into suspend
2110  * state until the control URB completes.
2111  */
2112 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
2113 			   u16 value, u16 index, const void *data, u16 size)
2114 {
2115 	struct usb_ctrlrequest *req = NULL;
2116 	struct urb *urb;
2117 	int err = -ENOMEM;
2118 	void *buf = NULL;
2119 
2120 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2121 		   " value=0x%04x index=0x%04x size=%d\n",
2122 		   cmd, reqtype, value, index, size);
2123 
2124 	urb = usb_alloc_urb(0, GFP_ATOMIC);
2125 	if (!urb)
2126 		goto fail;
2127 
2128 	if (data) {
2129 		buf = kmemdup(data, size, GFP_ATOMIC);
2130 		if (!buf) {
2131 			netdev_err(dev->net, "Error allocating buffer"
2132 				   " in %s!\n", __func__);
2133 			goto fail_free;
2134 		}
2135 	}
2136 
2137 	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
2138 	if (!req)
2139 		goto fail_free_buf;
2140 
2141 	req->bRequestType = reqtype;
2142 	req->bRequest = cmd;
2143 	req->wValue = cpu_to_le16(value);
2144 	req->wIndex = cpu_to_le16(index);
2145 	req->wLength = cpu_to_le16(size);
2146 
2147 	usb_fill_control_urb(urb, dev->udev,
2148 			     usb_sndctrlpipe(dev->udev, 0),
2149 			     (void *)req, buf, size,
2150 			     usbnet_async_cmd_cb, req);
2151 	urb->transfer_flags |= URB_FREE_BUFFER;
2152 
2153 	err = usb_submit_urb(urb, GFP_ATOMIC);
2154 	if (err < 0) {
2155 		netdev_err(dev->net, "Error submitting the control"
2156 			   " message: status=%d\n", err);
2157 		goto fail_free;
2158 	}
2159 	return 0;
2160 
2161 fail_free_buf:
2162 	kfree(buf);
2163 fail_free:
2164 	kfree(req);
2165 	usb_free_urb(urb);
2166 fail:
2167 	return err;
2168 
2169 }
2170 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
2171 /*-------------------------------------------------------------------------*/
2172 
2173 static int __init usbnet_init(void)
2174 {
2175 	/* Compiler should optimize this out. */
2176 	BUILD_BUG_ON(
2177 		FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
2178 
2179 	eth_random_addr(node_id);
2180 	return 0;
2181 }
2182 module_init(usbnet_init);
2183 
2184 static void __exit usbnet_exit(void)
2185 {
2186 }
2187 module_exit(usbnet_exit);
2188 
2189 MODULE_AUTHOR("David Brownell");
2190 MODULE_DESCRIPTION("USB network driver framework");
2191 MODULE_LICENSE("GPL");
2192