xref: /openbmc/linux/drivers/net/usb/usbnet.c (revision b4d0d230ccfb5d1a9ea85da64aa584df7c148ee9)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * USB Network driver infrastructure
4  * Copyright (C) 2000-2005 by David Brownell
5  * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.com>
6  */
7 
8 /*
9  * This is a generic "USB networking" framework that works with several
10  * kinds of full and high speed networking devices:  host-to-host cables,
11  * smart usb peripherals, and actual Ethernet adapters.
12  *
13  * These devices usually differ in terms of control protocols (if they
14  * even have one!) and sometimes they define new framing to wrap or batch
15  * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
16  * so interface (un)binding, endpoint I/O queues, fault handling, and other
17  * issues can usefully be addressed by this framework.
18  */
19 
20 // #define	DEBUG			// error path messages, extra info
21 // #define	VERBOSE			// more; success messages
22 
23 #include <linux/module.h>
24 #include <linux/init.h>
25 #include <linux/netdevice.h>
26 #include <linux/etherdevice.h>
27 #include <linux/ctype.h>
28 #include <linux/ethtool.h>
29 #include <linux/workqueue.h>
30 #include <linux/mii.h>
31 #include <linux/usb.h>
32 #include <linux/usb/usbnet.h>
33 #include <linux/slab.h>
34 #include <linux/kernel.h>
35 #include <linux/pm_runtime.h>
36 
37 #define DRIVER_VERSION		"22-Aug-2005"
38 
39 
40 /*-------------------------------------------------------------------------*/
41 
42 /*
43  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
44  * Several dozen bytes of IPv4 data can fit in two such transactions.
45  * One maximum size Ethernet packet takes twenty four of them.
46  * For high speed, each frame comfortably fits almost 36 max size
47  * Ethernet packets (so queues should be bigger).
48  *
49  * The goal is to let the USB host controller be busy for 5msec or
50  * more before an irq is required, under load.  Jumbograms change
51  * the equation.
52  */
53 #define	MAX_QUEUE_MEMORY	(60 * 1518)
54 #define	RX_QLEN(dev)		((dev)->rx_qlen)
55 #define	TX_QLEN(dev)		((dev)->tx_qlen)
56 
57 // reawaken network queue this soon after stopping; else watchdog barks
58 #define TX_TIMEOUT_JIFFIES	(5*HZ)
59 
60 /* throttle rx/tx briefly after some faults, so hub_wq might disconnect()
61  * us (it polls at HZ/4 usually) before we report too many false errors.
62  */
63 #define THROTTLE_JIFFIES	(HZ/8)
64 
65 // between wakeups
66 #define UNLINK_TIMEOUT_MS	3
67 
68 /*-------------------------------------------------------------------------*/
69 
70 // randomly generated ethernet address
71 static u8	node_id [ETH_ALEN];
72 
73 /* use ethtool to change the level for any given device */
74 static int msg_level = -1;
75 module_param (msg_level, int, 0);
76 MODULE_PARM_DESC (msg_level, "Override default message level");
77 
78 /*-------------------------------------------------------------------------*/
79 
80 /* handles CDC Ethernet and many other network "bulk data" interfaces */
81 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
82 {
83 	int				tmp;
84 	struct usb_host_interface	*alt = NULL;
85 	struct usb_host_endpoint	*in = NULL, *out = NULL;
86 	struct usb_host_endpoint	*status = NULL;
87 
88 	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
89 		unsigned	ep;
90 
91 		in = out = status = NULL;
92 		alt = intf->altsetting + tmp;
93 
94 		/* take the first altsetting with in-bulk + out-bulk;
95 		 * remember any status endpoint, just in case;
96 		 * ignore other endpoints and altsettings.
97 		 */
98 		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
99 			struct usb_host_endpoint	*e;
100 			int				intr = 0;
101 
102 			e = alt->endpoint + ep;
103 			switch (e->desc.bmAttributes) {
104 			case USB_ENDPOINT_XFER_INT:
105 				if (!usb_endpoint_dir_in(&e->desc))
106 					continue;
107 				intr = 1;
108 				/* FALLTHROUGH */
109 			case USB_ENDPOINT_XFER_BULK:
110 				break;
111 			default:
112 				continue;
113 			}
114 			if (usb_endpoint_dir_in(&e->desc)) {
115 				if (!intr && !in)
116 					in = e;
117 				else if (intr && !status)
118 					status = e;
119 			} else {
120 				if (!out)
121 					out = e;
122 			}
123 		}
124 		if (in && out)
125 			break;
126 	}
127 	if (!alt || !in || !out)
128 		return -EINVAL;
129 
130 	if (alt->desc.bAlternateSetting != 0 ||
131 	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
132 		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
133 				alt->desc.bAlternateSetting);
134 		if (tmp < 0)
135 			return tmp;
136 	}
137 
138 	dev->in = usb_rcvbulkpipe (dev->udev,
139 			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
140 	dev->out = usb_sndbulkpipe (dev->udev,
141 			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
142 	dev->status = status;
143 	return 0;
144 }
145 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
146 
147 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
148 {
149 	int 		tmp = -1, ret;
150 	unsigned char	buf [13];
151 
152 	ret = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
153 	if (ret == 12)
154 		tmp = hex2bin(dev->net->dev_addr, buf, 6);
155 	if (tmp < 0) {
156 		dev_dbg(&dev->udev->dev,
157 			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
158 		if (ret >= 0)
159 			ret = -EINVAL;
160 		return ret;
161 	}
162 	return 0;
163 }
164 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
165 
166 static void intr_complete (struct urb *urb)
167 {
168 	struct usbnet	*dev = urb->context;
169 	int		status = urb->status;
170 
171 	switch (status) {
172 	/* success */
173 	case 0:
174 		dev->driver_info->status(dev, urb);
175 		break;
176 
177 	/* software-driven interface shutdown */
178 	case -ENOENT:		/* urb killed */
179 	case -ESHUTDOWN:	/* hardware gone */
180 		netif_dbg(dev, ifdown, dev->net,
181 			  "intr shutdown, code %d\n", status);
182 		return;
183 
184 	/* NOTE:  not throttling like RX/TX, since this endpoint
185 	 * already polls infrequently
186 	 */
187 	default:
188 		netdev_dbg(dev->net, "intr status %d\n", status);
189 		break;
190 	}
191 
192 	status = usb_submit_urb (urb, GFP_ATOMIC);
193 	if (status != 0)
194 		netif_err(dev, timer, dev->net,
195 			  "intr resubmit --> %d\n", status);
196 }
197 
198 static int init_status (struct usbnet *dev, struct usb_interface *intf)
199 {
200 	char		*buf = NULL;
201 	unsigned	pipe = 0;
202 	unsigned	maxp;
203 	unsigned	period;
204 
205 	if (!dev->driver_info->status)
206 		return 0;
207 
208 	pipe = usb_rcvintpipe (dev->udev,
209 			dev->status->desc.bEndpointAddress
210 				& USB_ENDPOINT_NUMBER_MASK);
211 	maxp = usb_maxpacket (dev->udev, pipe, 0);
212 
213 	/* avoid 1 msec chatter:  min 8 msec poll rate */
214 	period = max ((int) dev->status->desc.bInterval,
215 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
216 
217 	buf = kmalloc (maxp, GFP_KERNEL);
218 	if (buf) {
219 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
220 		if (!dev->interrupt) {
221 			kfree (buf);
222 			return -ENOMEM;
223 		} else {
224 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
225 				buf, maxp, intr_complete, dev, period);
226 			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
227 			dev_dbg(&intf->dev,
228 				"status ep%din, %d bytes period %d\n",
229 				usb_pipeendpoint(pipe), maxp, period);
230 		}
231 	}
232 	return 0;
233 }
234 
235 /* Submit the interrupt URB if not previously submitted, increasing refcount */
236 int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
237 {
238 	int ret = 0;
239 
240 	WARN_ON_ONCE(dev->interrupt == NULL);
241 	if (dev->interrupt) {
242 		mutex_lock(&dev->interrupt_mutex);
243 
244 		if (++dev->interrupt_count == 1)
245 			ret = usb_submit_urb(dev->interrupt, mem_flags);
246 
247 		dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
248 			dev->interrupt_count);
249 		mutex_unlock(&dev->interrupt_mutex);
250 	}
251 	return ret;
252 }
253 EXPORT_SYMBOL_GPL(usbnet_status_start);
254 
255 /* For resume; submit interrupt URB if previously submitted */
256 static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
257 {
258 	int ret = 0;
259 
260 	mutex_lock(&dev->interrupt_mutex);
261 	if (dev->interrupt_count) {
262 		ret = usb_submit_urb(dev->interrupt, mem_flags);
263 		dev_dbg(&dev->udev->dev,
264 			"submitted interrupt URB for resume\n");
265 	}
266 	mutex_unlock(&dev->interrupt_mutex);
267 	return ret;
268 }
269 
270 /* Kill the interrupt URB if all submitters want it killed */
271 void usbnet_status_stop(struct usbnet *dev)
272 {
273 	if (dev->interrupt) {
274 		mutex_lock(&dev->interrupt_mutex);
275 		WARN_ON(dev->interrupt_count == 0);
276 
277 		if (dev->interrupt_count && --dev->interrupt_count == 0)
278 			usb_kill_urb(dev->interrupt);
279 
280 		dev_dbg(&dev->udev->dev,
281 			"decremented interrupt URB count to %d\n",
282 			dev->interrupt_count);
283 		mutex_unlock(&dev->interrupt_mutex);
284 	}
285 }
286 EXPORT_SYMBOL_GPL(usbnet_status_stop);
287 
288 /* For suspend; always kill interrupt URB */
289 static void __usbnet_status_stop_force(struct usbnet *dev)
290 {
291 	if (dev->interrupt) {
292 		mutex_lock(&dev->interrupt_mutex);
293 		usb_kill_urb(dev->interrupt);
294 		dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
295 		mutex_unlock(&dev->interrupt_mutex);
296 	}
297 }
298 
299 /* Passes this packet up the stack, updating its accounting.
300  * Some link protocols batch packets, so their rx_fixup paths
301  * can return clones as well as just modify the original skb.
302  */
303 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
304 {
305 	struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->stats64);
306 	unsigned long flags;
307 	int	status;
308 
309 	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
310 		skb_queue_tail(&dev->rxq_pause, skb);
311 		return;
312 	}
313 
314 	/* only update if unset to allow minidriver rx_fixup override */
315 	if (skb->protocol == 0)
316 		skb->protocol = eth_type_trans (skb, dev->net);
317 
318 	flags = u64_stats_update_begin_irqsave(&stats64->syncp);
319 	stats64->rx_packets++;
320 	stats64->rx_bytes += skb->len;
321 	u64_stats_update_end_irqrestore(&stats64->syncp, flags);
322 
323 	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
324 		  skb->len + sizeof (struct ethhdr), skb->protocol);
325 	memset (skb->cb, 0, sizeof (struct skb_data));
326 
327 	if (skb_defer_rx_timestamp(skb))
328 		return;
329 
330 	status = netif_rx (skb);
331 	if (status != NET_RX_SUCCESS)
332 		netif_dbg(dev, rx_err, dev->net,
333 			  "netif_rx status %d\n", status);
334 }
335 EXPORT_SYMBOL_GPL(usbnet_skb_return);
336 
337 /* must be called if hard_mtu or rx_urb_size changed */
338 void usbnet_update_max_qlen(struct usbnet *dev)
339 {
340 	enum usb_device_speed speed = dev->udev->speed;
341 
342 	switch (speed) {
343 	case USB_SPEED_HIGH:
344 		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
345 		dev->tx_qlen = MAX_QUEUE_MEMORY / dev->hard_mtu;
346 		break;
347 	case USB_SPEED_SUPER:
348 	case USB_SPEED_SUPER_PLUS:
349 		/*
350 		 * Not take default 5ms qlen for super speed HC to
351 		 * save memory, and iperf tests show 2.5ms qlen can
352 		 * work well
353 		 */
354 		dev->rx_qlen = 5 * MAX_QUEUE_MEMORY / dev->rx_urb_size;
355 		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
356 		break;
357 	default:
358 		dev->rx_qlen = dev->tx_qlen = 4;
359 	}
360 }
361 EXPORT_SYMBOL_GPL(usbnet_update_max_qlen);
362 
363 
364 /*-------------------------------------------------------------------------
365  *
366  * Network Device Driver (peer link to "Host Device", from USB host)
367  *
368  *-------------------------------------------------------------------------*/
369 
370 int usbnet_change_mtu (struct net_device *net, int new_mtu)
371 {
372 	struct usbnet	*dev = netdev_priv(net);
373 	int		ll_mtu = new_mtu + net->hard_header_len;
374 	int		old_hard_mtu = dev->hard_mtu;
375 	int		old_rx_urb_size = dev->rx_urb_size;
376 
377 	// no second zero-length packet read wanted after mtu-sized packets
378 	if ((ll_mtu % dev->maxpacket) == 0)
379 		return -EDOM;
380 	net->mtu = new_mtu;
381 
382 	dev->hard_mtu = net->mtu + net->hard_header_len;
383 	if (dev->rx_urb_size == old_hard_mtu) {
384 		dev->rx_urb_size = dev->hard_mtu;
385 		if (dev->rx_urb_size > old_rx_urb_size) {
386 			usbnet_pause_rx(dev);
387 			usbnet_unlink_rx_urbs(dev);
388 			usbnet_resume_rx(dev);
389 		}
390 	}
391 
392 	/* max qlen depend on hard_mtu and rx_urb_size */
393 	usbnet_update_max_qlen(dev);
394 
395 	return 0;
396 }
397 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
398 
399 /* The caller must hold list->lock */
400 static void __usbnet_queue_skb(struct sk_buff_head *list,
401 			struct sk_buff *newsk, enum skb_state state)
402 {
403 	struct skb_data *entry = (struct skb_data *) newsk->cb;
404 
405 	__skb_queue_tail(list, newsk);
406 	entry->state = state;
407 }
408 
409 /*-------------------------------------------------------------------------*/
410 
411 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
412  * completion callbacks.  2.5 should have fixed those bugs...
413  */
414 
415 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
416 		struct sk_buff_head *list, enum skb_state state)
417 {
418 	unsigned long		flags;
419 	enum skb_state 		old_state;
420 	struct skb_data *entry = (struct skb_data *) skb->cb;
421 
422 	spin_lock_irqsave(&list->lock, flags);
423 	old_state = entry->state;
424 	entry->state = state;
425 	__skb_unlink(skb, list);
426 
427 	/* defer_bh() is never called with list == &dev->done.
428 	 * spin_lock_nested() tells lockdep that it is OK to take
429 	 * dev->done.lock here with list->lock held.
430 	 */
431 	spin_lock_nested(&dev->done.lock, SINGLE_DEPTH_NESTING);
432 
433 	__skb_queue_tail(&dev->done, skb);
434 	if (dev->done.qlen == 1)
435 		tasklet_schedule(&dev->bh);
436 	spin_unlock(&dev->done.lock);
437 	spin_unlock_irqrestore(&list->lock, flags);
438 	return old_state;
439 }
440 
441 /* some work can't be done in tasklets, so we use keventd
442  *
443  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
444  * but tasklet_schedule() doesn't.  hope the failure is rare.
445  */
446 void usbnet_defer_kevent (struct usbnet *dev, int work)
447 {
448 	set_bit (work, &dev->flags);
449 	if (!schedule_work (&dev->kevent))
450 		netdev_dbg(dev->net, "kevent %d may have been dropped\n", work);
451 	else
452 		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
453 }
454 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
455 
456 /*-------------------------------------------------------------------------*/
457 
458 static void rx_complete (struct urb *urb);
459 
460 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
461 {
462 	struct sk_buff		*skb;
463 	struct skb_data		*entry;
464 	int			retval = 0;
465 	unsigned long		lockflags;
466 	size_t			size = dev->rx_urb_size;
467 
468 	/* prevent rx skb allocation when error ratio is high */
469 	if (test_bit(EVENT_RX_KILL, &dev->flags)) {
470 		usb_free_urb(urb);
471 		return -ENOLINK;
472 	}
473 
474 	if (test_bit(EVENT_NO_IP_ALIGN, &dev->flags))
475 		skb = __netdev_alloc_skb(dev->net, size, flags);
476 	else
477 		skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
478 	if (!skb) {
479 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
480 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
481 		usb_free_urb (urb);
482 		return -ENOMEM;
483 	}
484 
485 	entry = (struct skb_data *) skb->cb;
486 	entry->urb = urb;
487 	entry->dev = dev;
488 	entry->length = 0;
489 
490 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
491 		skb->data, size, rx_complete, skb);
492 
493 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
494 
495 	if (netif_running (dev->net) &&
496 	    netif_device_present (dev->net) &&
497 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
498 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
499 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
500 		case -EPIPE:
501 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
502 			break;
503 		case -ENOMEM:
504 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
505 			break;
506 		case -ENODEV:
507 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
508 			netif_device_detach (dev->net);
509 			break;
510 		case -EHOSTUNREACH:
511 			retval = -ENOLINK;
512 			break;
513 		default:
514 			netif_dbg(dev, rx_err, dev->net,
515 				  "rx submit, %d\n", retval);
516 			tasklet_schedule (&dev->bh);
517 			break;
518 		case 0:
519 			__usbnet_queue_skb(&dev->rxq, skb, rx_start);
520 		}
521 	} else {
522 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
523 		retval = -ENOLINK;
524 	}
525 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
526 	if (retval) {
527 		dev_kfree_skb_any (skb);
528 		usb_free_urb (urb);
529 	}
530 	return retval;
531 }
532 
533 
534 /*-------------------------------------------------------------------------*/
535 
536 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
537 {
538 	if (dev->driver_info->rx_fixup &&
539 	    !dev->driver_info->rx_fixup (dev, skb)) {
540 		/* With RX_ASSEMBLE, rx_fixup() must update counters */
541 		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
542 			dev->net->stats.rx_errors++;
543 		goto done;
544 	}
545 	// else network stack removes extra byte if we forced a short packet
546 
547 	/* all data was already cloned from skb inside the driver */
548 	if (dev->driver_info->flags & FLAG_MULTI_PACKET)
549 		goto done;
550 
551 	if (skb->len < ETH_HLEN) {
552 		dev->net->stats.rx_errors++;
553 		dev->net->stats.rx_length_errors++;
554 		netif_dbg(dev, rx_err, dev->net, "rx length %d\n", skb->len);
555 	} else {
556 		usbnet_skb_return(dev, skb);
557 		return;
558 	}
559 
560 done:
561 	skb_queue_tail(&dev->done, skb);
562 }
563 
564 /*-------------------------------------------------------------------------*/
565 
566 static void rx_complete (struct urb *urb)
567 {
568 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
569 	struct skb_data		*entry = (struct skb_data *) skb->cb;
570 	struct usbnet		*dev = entry->dev;
571 	int			urb_status = urb->status;
572 	enum skb_state		state;
573 
574 	skb_put (skb, urb->actual_length);
575 	state = rx_done;
576 	entry->urb = NULL;
577 
578 	switch (urb_status) {
579 	/* success */
580 	case 0:
581 		break;
582 
583 	/* stalls need manual reset. this is rare ... except that
584 	 * when going through USB 2.0 TTs, unplug appears this way.
585 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
586 	 * storm, recovering as needed.
587 	 */
588 	case -EPIPE:
589 		dev->net->stats.rx_errors++;
590 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
591 		// FALLTHROUGH
592 
593 	/* software-driven interface shutdown */
594 	case -ECONNRESET:		/* async unlink */
595 	case -ESHUTDOWN:		/* hardware gone */
596 		netif_dbg(dev, ifdown, dev->net,
597 			  "rx shutdown, code %d\n", urb_status);
598 		goto block;
599 
600 	/* we get controller i/o faults during hub_wq disconnect() delays.
601 	 * throttle down resubmits, to avoid log floods; just temporarily,
602 	 * so we still recover when the fault isn't a hub_wq delay.
603 	 */
604 	case -EPROTO:
605 	case -ETIME:
606 	case -EILSEQ:
607 		dev->net->stats.rx_errors++;
608 		if (!timer_pending (&dev->delay)) {
609 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
610 			netif_dbg(dev, link, dev->net,
611 				  "rx throttle %d\n", urb_status);
612 		}
613 block:
614 		state = rx_cleanup;
615 		entry->urb = urb;
616 		urb = NULL;
617 		break;
618 
619 	/* data overrun ... flush fifo? */
620 	case -EOVERFLOW:
621 		dev->net->stats.rx_over_errors++;
622 		// FALLTHROUGH
623 
624 	default:
625 		state = rx_cleanup;
626 		dev->net->stats.rx_errors++;
627 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
628 		break;
629 	}
630 
631 	/* stop rx if packet error rate is high */
632 	if (++dev->pkt_cnt > 30) {
633 		dev->pkt_cnt = 0;
634 		dev->pkt_err = 0;
635 	} else {
636 		if (state == rx_cleanup)
637 			dev->pkt_err++;
638 		if (dev->pkt_err > 20)
639 			set_bit(EVENT_RX_KILL, &dev->flags);
640 	}
641 
642 	state = defer_bh(dev, skb, &dev->rxq, state);
643 
644 	if (urb) {
645 		if (netif_running (dev->net) &&
646 		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
647 		    state != unlink_start) {
648 			rx_submit (dev, urb, GFP_ATOMIC);
649 			usb_mark_last_busy(dev->udev);
650 			return;
651 		}
652 		usb_free_urb (urb);
653 	}
654 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
655 }
656 
657 /*-------------------------------------------------------------------------*/
658 void usbnet_pause_rx(struct usbnet *dev)
659 {
660 	set_bit(EVENT_RX_PAUSED, &dev->flags);
661 
662 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
663 }
664 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
665 
666 void usbnet_resume_rx(struct usbnet *dev)
667 {
668 	struct sk_buff *skb;
669 	int num = 0;
670 
671 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
672 
673 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
674 		usbnet_skb_return(dev, skb);
675 		num++;
676 	}
677 
678 	tasklet_schedule(&dev->bh);
679 
680 	netif_dbg(dev, rx_status, dev->net,
681 		  "paused rx queue disabled, %d skbs requeued\n", num);
682 }
683 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
684 
685 void usbnet_purge_paused_rxq(struct usbnet *dev)
686 {
687 	skb_queue_purge(&dev->rxq_pause);
688 }
689 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
690 
691 /*-------------------------------------------------------------------------*/
692 
693 // unlink pending rx/tx; completion handlers do all other cleanup
694 
695 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
696 {
697 	unsigned long		flags;
698 	struct sk_buff		*skb;
699 	int			count = 0;
700 
701 	spin_lock_irqsave (&q->lock, flags);
702 	while (!skb_queue_empty(q)) {
703 		struct skb_data		*entry;
704 		struct urb		*urb;
705 		int			retval;
706 
707 		skb_queue_walk(q, skb) {
708 			entry = (struct skb_data *) skb->cb;
709 			if (entry->state != unlink_start)
710 				goto found;
711 		}
712 		break;
713 found:
714 		entry->state = unlink_start;
715 		urb = entry->urb;
716 
717 		/*
718 		 * Get reference count of the URB to avoid it to be
719 		 * freed during usb_unlink_urb, which may trigger
720 		 * use-after-free problem inside usb_unlink_urb since
721 		 * usb_unlink_urb is always racing with .complete
722 		 * handler(include defer_bh).
723 		 */
724 		usb_get_urb(urb);
725 		spin_unlock_irqrestore(&q->lock, flags);
726 		// during some PM-driven resume scenarios,
727 		// these (async) unlinks complete immediately
728 		retval = usb_unlink_urb (urb);
729 		if (retval != -EINPROGRESS && retval != 0)
730 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
731 		else
732 			count++;
733 		usb_put_urb(urb);
734 		spin_lock_irqsave(&q->lock, flags);
735 	}
736 	spin_unlock_irqrestore (&q->lock, flags);
737 	return count;
738 }
739 
740 // Flush all pending rx urbs
741 // minidrivers may need to do this when the MTU changes
742 
743 void usbnet_unlink_rx_urbs(struct usbnet *dev)
744 {
745 	if (netif_running(dev->net)) {
746 		(void) unlink_urbs (dev, &dev->rxq);
747 		tasklet_schedule(&dev->bh);
748 	}
749 }
750 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
751 
752 /*-------------------------------------------------------------------------*/
753 
754 static void wait_skb_queue_empty(struct sk_buff_head *q)
755 {
756 	unsigned long flags;
757 
758 	spin_lock_irqsave(&q->lock, flags);
759 	while (!skb_queue_empty(q)) {
760 		spin_unlock_irqrestore(&q->lock, flags);
761 		schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
762 		set_current_state(TASK_UNINTERRUPTIBLE);
763 		spin_lock_irqsave(&q->lock, flags);
764 	}
765 	spin_unlock_irqrestore(&q->lock, flags);
766 }
767 
768 // precondition: never called in_interrupt
769 static void usbnet_terminate_urbs(struct usbnet *dev)
770 {
771 	DECLARE_WAITQUEUE(wait, current);
772 	int temp;
773 
774 	/* ensure there are no more active urbs */
775 	add_wait_queue(&dev->wait, &wait);
776 	set_current_state(TASK_UNINTERRUPTIBLE);
777 	temp = unlink_urbs(dev, &dev->txq) +
778 		unlink_urbs(dev, &dev->rxq);
779 
780 	/* maybe wait for deletions to finish. */
781 	wait_skb_queue_empty(&dev->rxq);
782 	wait_skb_queue_empty(&dev->txq);
783 	wait_skb_queue_empty(&dev->done);
784 	netif_dbg(dev, ifdown, dev->net,
785 		  "waited for %d urb completions\n", temp);
786 	set_current_state(TASK_RUNNING);
787 	remove_wait_queue(&dev->wait, &wait);
788 }
789 
790 int usbnet_stop (struct net_device *net)
791 {
792 	struct usbnet		*dev = netdev_priv(net);
793 	const struct driver_info *info = dev->driver_info;
794 	int			retval, pm, mpn;
795 
796 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
797 	netif_stop_queue (net);
798 
799 	netif_info(dev, ifdown, dev->net,
800 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
801 		   net->stats.rx_packets, net->stats.tx_packets,
802 		   net->stats.rx_errors, net->stats.tx_errors);
803 
804 	/* to not race resume */
805 	pm = usb_autopm_get_interface(dev->intf);
806 	/* allow minidriver to stop correctly (wireless devices to turn off
807 	 * radio etc) */
808 	if (info->stop) {
809 		retval = info->stop(dev);
810 		if (retval < 0)
811 			netif_info(dev, ifdown, dev->net,
812 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
813 				   retval,
814 				   dev->udev->bus->bus_name, dev->udev->devpath,
815 				   info->description);
816 	}
817 
818 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
819 		usbnet_terminate_urbs(dev);
820 
821 	usbnet_status_stop(dev);
822 
823 	usbnet_purge_paused_rxq(dev);
824 
825 	mpn = !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
826 
827 	/* deferred work (task, timer, softirq) must also stop.
828 	 * can't flush_scheduled_work() until we drop rtnl (later),
829 	 * else workers could deadlock; so make workers a NOP.
830 	 */
831 	dev->flags = 0;
832 	del_timer_sync (&dev->delay);
833 	tasklet_kill (&dev->bh);
834 	if (!pm)
835 		usb_autopm_put_interface(dev->intf);
836 
837 	if (info->manage_power && mpn)
838 		info->manage_power(dev, 0);
839 	else
840 		usb_autopm_put_interface(dev->intf);
841 
842 	return 0;
843 }
844 EXPORT_SYMBOL_GPL(usbnet_stop);
845 
846 /*-------------------------------------------------------------------------*/
847 
848 // posts reads, and enables write queuing
849 
850 // precondition: never called in_interrupt
851 
852 int usbnet_open (struct net_device *net)
853 {
854 	struct usbnet		*dev = netdev_priv(net);
855 	int			retval;
856 	const struct driver_info *info = dev->driver_info;
857 
858 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
859 		netif_info(dev, ifup, dev->net,
860 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
861 			   retval,
862 			   dev->udev->bus->bus_name,
863 			   dev->udev->devpath,
864 			   info->description);
865 		goto done_nopm;
866 	}
867 
868 	// put into "known safe" state
869 	if (info->reset && (retval = info->reset (dev)) < 0) {
870 		netif_info(dev, ifup, dev->net,
871 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
872 			   retval,
873 			   dev->udev->bus->bus_name,
874 			   dev->udev->devpath,
875 			   info->description);
876 		goto done;
877 	}
878 
879 	/* hard_mtu or rx_urb_size may change in reset() */
880 	usbnet_update_max_qlen(dev);
881 
882 	// insist peer be connected
883 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
884 		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
885 		goto done;
886 	}
887 
888 	/* start any status interrupt transfer */
889 	if (dev->interrupt) {
890 		retval = usbnet_status_start(dev, GFP_KERNEL);
891 		if (retval < 0) {
892 			netif_err(dev, ifup, dev->net,
893 				  "intr submit %d\n", retval);
894 			goto done;
895 		}
896 	}
897 
898 	set_bit(EVENT_DEV_OPEN, &dev->flags);
899 	netif_start_queue (net);
900 	netif_info(dev, ifup, dev->net,
901 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
902 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
903 		   dev->net->mtu,
904 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
905 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
906 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
907 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
908 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
909 		   "simple");
910 
911 	/* reset rx error state */
912 	dev->pkt_cnt = 0;
913 	dev->pkt_err = 0;
914 	clear_bit(EVENT_RX_KILL, &dev->flags);
915 
916 	// delay posting reads until we're fully open
917 	tasklet_schedule (&dev->bh);
918 	if (info->manage_power) {
919 		retval = info->manage_power(dev, 1);
920 		if (retval < 0) {
921 			retval = 0;
922 			set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
923 		} else {
924 			usb_autopm_put_interface(dev->intf);
925 		}
926 	}
927 	return retval;
928 done:
929 	usb_autopm_put_interface(dev->intf);
930 done_nopm:
931 	return retval;
932 }
933 EXPORT_SYMBOL_GPL(usbnet_open);
934 
935 /*-------------------------------------------------------------------------*/
936 
937 /* ethtool methods; minidrivers may need to add some more, but
938  * they'll probably want to use this base set.
939  */
940 
941 int usbnet_get_link_ksettings(struct net_device *net,
942 			      struct ethtool_link_ksettings *cmd)
943 {
944 	struct usbnet *dev = netdev_priv(net);
945 
946 	if (!dev->mii.mdio_read)
947 		return -EOPNOTSUPP;
948 
949 	mii_ethtool_get_link_ksettings(&dev->mii, cmd);
950 
951 	return 0;
952 }
953 EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings);
954 
955 int usbnet_set_link_ksettings(struct net_device *net,
956 			      const struct ethtool_link_ksettings *cmd)
957 {
958 	struct usbnet *dev = netdev_priv(net);
959 	int retval;
960 
961 	if (!dev->mii.mdio_write)
962 		return -EOPNOTSUPP;
963 
964 	retval = mii_ethtool_set_link_ksettings(&dev->mii, cmd);
965 
966 	/* link speed/duplex might have changed */
967 	if (dev->driver_info->link_reset)
968 		dev->driver_info->link_reset(dev);
969 
970 	/* hard_mtu or rx_urb_size may change in link_reset() */
971 	usbnet_update_max_qlen(dev);
972 
973 	return retval;
974 }
975 EXPORT_SYMBOL_GPL(usbnet_set_link_ksettings);
976 
977 void usbnet_get_stats64(struct net_device *net, struct rtnl_link_stats64 *stats)
978 {
979 	struct usbnet *dev = netdev_priv(net);
980 	unsigned int start;
981 	int cpu;
982 
983 	netdev_stats_to_stats64(stats, &net->stats);
984 
985 	for_each_possible_cpu(cpu) {
986 		struct pcpu_sw_netstats *stats64;
987 		u64 rx_packets, rx_bytes;
988 		u64 tx_packets, tx_bytes;
989 
990 		stats64 = per_cpu_ptr(dev->stats64, cpu);
991 
992 		do {
993 			start = u64_stats_fetch_begin_irq(&stats64->syncp);
994 			rx_packets = stats64->rx_packets;
995 			rx_bytes = stats64->rx_bytes;
996 			tx_packets = stats64->tx_packets;
997 			tx_bytes = stats64->tx_bytes;
998 		} while (u64_stats_fetch_retry_irq(&stats64->syncp, start));
999 
1000 		stats->rx_packets += rx_packets;
1001 		stats->rx_bytes += rx_bytes;
1002 		stats->tx_packets += tx_packets;
1003 		stats->tx_bytes += tx_bytes;
1004 	}
1005 }
1006 EXPORT_SYMBOL_GPL(usbnet_get_stats64);
1007 
1008 u32 usbnet_get_link (struct net_device *net)
1009 {
1010 	struct usbnet *dev = netdev_priv(net);
1011 
1012 	/* If a check_connect is defined, return its result */
1013 	if (dev->driver_info->check_connect)
1014 		return dev->driver_info->check_connect (dev) == 0;
1015 
1016 	/* if the device has mii operations, use those */
1017 	if (dev->mii.mdio_read)
1018 		return mii_link_ok(&dev->mii);
1019 
1020 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
1021 	return ethtool_op_get_link(net);
1022 }
1023 EXPORT_SYMBOL_GPL(usbnet_get_link);
1024 
1025 int usbnet_nway_reset(struct net_device *net)
1026 {
1027 	struct usbnet *dev = netdev_priv(net);
1028 
1029 	if (!dev->mii.mdio_write)
1030 		return -EOPNOTSUPP;
1031 
1032 	return mii_nway_restart(&dev->mii);
1033 }
1034 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
1035 
1036 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
1037 {
1038 	struct usbnet *dev = netdev_priv(net);
1039 
1040 	strlcpy (info->driver, dev->driver_name, sizeof info->driver);
1041 	strlcpy (info->version, DRIVER_VERSION, sizeof info->version);
1042 	strlcpy (info->fw_version, dev->driver_info->description,
1043 		sizeof info->fw_version);
1044 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
1045 }
1046 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
1047 
1048 u32 usbnet_get_msglevel (struct net_device *net)
1049 {
1050 	struct usbnet *dev = netdev_priv(net);
1051 
1052 	return dev->msg_enable;
1053 }
1054 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
1055 
1056 void usbnet_set_msglevel (struct net_device *net, u32 level)
1057 {
1058 	struct usbnet *dev = netdev_priv(net);
1059 
1060 	dev->msg_enable = level;
1061 }
1062 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
1063 
1064 /* drivers may override default ethtool_ops in their bind() routine */
1065 static const struct ethtool_ops usbnet_ethtool_ops = {
1066 	.get_link		= usbnet_get_link,
1067 	.nway_reset		= usbnet_nway_reset,
1068 	.get_drvinfo		= usbnet_get_drvinfo,
1069 	.get_msglevel		= usbnet_get_msglevel,
1070 	.set_msglevel		= usbnet_set_msglevel,
1071 	.get_ts_info		= ethtool_op_get_ts_info,
1072 	.get_link_ksettings	= usbnet_get_link_ksettings,
1073 	.set_link_ksettings	= usbnet_set_link_ksettings,
1074 };
1075 
1076 /*-------------------------------------------------------------------------*/
1077 
1078 static void __handle_link_change(struct usbnet *dev)
1079 {
1080 	if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
1081 		return;
1082 
1083 	if (!netif_carrier_ok(dev->net)) {
1084 		/* kill URBs for reading packets to save bus bandwidth */
1085 		unlink_urbs(dev, &dev->rxq);
1086 
1087 		/*
1088 		 * tx_timeout will unlink URBs for sending packets and
1089 		 * tx queue is stopped by netcore after link becomes off
1090 		 */
1091 	} else {
1092 		/* submitting URBs for reading packets */
1093 		tasklet_schedule(&dev->bh);
1094 	}
1095 
1096 	/* hard_mtu or rx_urb_size may change during link change */
1097 	usbnet_update_max_qlen(dev);
1098 
1099 	clear_bit(EVENT_LINK_CHANGE, &dev->flags);
1100 }
1101 
1102 static void usbnet_set_rx_mode(struct net_device *net)
1103 {
1104 	struct usbnet		*dev = netdev_priv(net);
1105 
1106 	usbnet_defer_kevent(dev, EVENT_SET_RX_MODE);
1107 }
1108 
1109 static void __handle_set_rx_mode(struct usbnet *dev)
1110 {
1111 	if (dev->driver_info->set_rx_mode)
1112 		(dev->driver_info->set_rx_mode)(dev);
1113 
1114 	clear_bit(EVENT_SET_RX_MODE, &dev->flags);
1115 }
1116 
1117 /* work that cannot be done in interrupt context uses keventd.
1118  *
1119  * NOTE:  with 2.5 we could do more of this using completion callbacks,
1120  * especially now that control transfers can be queued.
1121  */
1122 static void
1123 usbnet_deferred_kevent (struct work_struct *work)
1124 {
1125 	struct usbnet		*dev =
1126 		container_of(work, struct usbnet, kevent);
1127 	int			status;
1128 
1129 	/* usb_clear_halt() needs a thread context */
1130 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
1131 		unlink_urbs (dev, &dev->txq);
1132 		status = usb_autopm_get_interface(dev->intf);
1133 		if (status < 0)
1134 			goto fail_pipe;
1135 		status = usb_clear_halt (dev->udev, dev->out);
1136 		usb_autopm_put_interface(dev->intf);
1137 		if (status < 0 &&
1138 		    status != -EPIPE &&
1139 		    status != -ESHUTDOWN) {
1140 			if (netif_msg_tx_err (dev))
1141 fail_pipe:
1142 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
1143 					   status);
1144 		} else {
1145 			clear_bit (EVENT_TX_HALT, &dev->flags);
1146 			if (status != -ESHUTDOWN)
1147 				netif_wake_queue (dev->net);
1148 		}
1149 	}
1150 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
1151 		unlink_urbs (dev, &dev->rxq);
1152 		status = usb_autopm_get_interface(dev->intf);
1153 		if (status < 0)
1154 			goto fail_halt;
1155 		status = usb_clear_halt (dev->udev, dev->in);
1156 		usb_autopm_put_interface(dev->intf);
1157 		if (status < 0 &&
1158 		    status != -EPIPE &&
1159 		    status != -ESHUTDOWN) {
1160 			if (netif_msg_rx_err (dev))
1161 fail_halt:
1162 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
1163 					   status);
1164 		} else {
1165 			clear_bit (EVENT_RX_HALT, &dev->flags);
1166 			tasklet_schedule (&dev->bh);
1167 		}
1168 	}
1169 
1170 	/* tasklet could resubmit itself forever if memory is tight */
1171 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
1172 		struct urb	*urb = NULL;
1173 		int resched = 1;
1174 
1175 		if (netif_running (dev->net))
1176 			urb = usb_alloc_urb (0, GFP_KERNEL);
1177 		else
1178 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1179 		if (urb != NULL) {
1180 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1181 			status = usb_autopm_get_interface(dev->intf);
1182 			if (status < 0) {
1183 				usb_free_urb(urb);
1184 				goto fail_lowmem;
1185 			}
1186 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
1187 				resched = 0;
1188 			usb_autopm_put_interface(dev->intf);
1189 fail_lowmem:
1190 			if (resched)
1191 				tasklet_schedule (&dev->bh);
1192 		}
1193 	}
1194 
1195 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
1196 		const struct driver_info *info = dev->driver_info;
1197 		int			retval = 0;
1198 
1199 		clear_bit (EVENT_LINK_RESET, &dev->flags);
1200 		status = usb_autopm_get_interface(dev->intf);
1201 		if (status < 0)
1202 			goto skip_reset;
1203 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1204 			usb_autopm_put_interface(dev->intf);
1205 skip_reset:
1206 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1207 				    retval,
1208 				    dev->udev->bus->bus_name,
1209 				    dev->udev->devpath,
1210 				    info->description);
1211 		} else {
1212 			usb_autopm_put_interface(dev->intf);
1213 		}
1214 
1215 		/* handle link change from link resetting */
1216 		__handle_link_change(dev);
1217 	}
1218 
1219 	if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
1220 		__handle_link_change(dev);
1221 
1222 	if (test_bit (EVENT_SET_RX_MODE, &dev->flags))
1223 		__handle_set_rx_mode(dev);
1224 
1225 
1226 	if (dev->flags)
1227 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1228 }
1229 
1230 /*-------------------------------------------------------------------------*/
1231 
1232 static void tx_complete (struct urb *urb)
1233 {
1234 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1235 	struct skb_data		*entry = (struct skb_data *) skb->cb;
1236 	struct usbnet		*dev = entry->dev;
1237 
1238 	if (urb->status == 0) {
1239 		struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->stats64);
1240 		unsigned long flags;
1241 
1242 		flags = u64_stats_update_begin_irqsave(&stats64->syncp);
1243 		stats64->tx_packets += entry->packets;
1244 		stats64->tx_bytes += entry->length;
1245 		u64_stats_update_end_irqrestore(&stats64->syncp, flags);
1246 	} else {
1247 		dev->net->stats.tx_errors++;
1248 
1249 		switch (urb->status) {
1250 		case -EPIPE:
1251 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1252 			break;
1253 
1254 		/* software-driven interface shutdown */
1255 		case -ECONNRESET:		// async unlink
1256 		case -ESHUTDOWN:		// hardware gone
1257 			break;
1258 
1259 		/* like rx, tx gets controller i/o faults during hub_wq
1260 		 * delays and so it uses the same throttling mechanism.
1261 		 */
1262 		case -EPROTO:
1263 		case -ETIME:
1264 		case -EILSEQ:
1265 			usb_mark_last_busy(dev->udev);
1266 			if (!timer_pending (&dev->delay)) {
1267 				mod_timer (&dev->delay,
1268 					jiffies + THROTTLE_JIFFIES);
1269 				netif_dbg(dev, link, dev->net,
1270 					  "tx throttle %d\n", urb->status);
1271 			}
1272 			netif_stop_queue (dev->net);
1273 			break;
1274 		default:
1275 			netif_dbg(dev, tx_err, dev->net,
1276 				  "tx err %d\n", entry->urb->status);
1277 			break;
1278 		}
1279 	}
1280 
1281 	usb_autopm_put_interface_async(dev->intf);
1282 	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1283 }
1284 
1285 /*-------------------------------------------------------------------------*/
1286 
1287 void usbnet_tx_timeout (struct net_device *net)
1288 {
1289 	struct usbnet		*dev = netdev_priv(net);
1290 
1291 	unlink_urbs (dev, &dev->txq);
1292 	tasklet_schedule (&dev->bh);
1293 	/* this needs to be handled individually because the generic layer
1294 	 * doesn't know what is sufficient and could not restore private
1295 	 * information if a remedy of an unconditional reset were used.
1296 	 */
1297 	if (dev->driver_info->recover)
1298 		(dev->driver_info->recover)(dev);
1299 }
1300 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1301 
1302 /*-------------------------------------------------------------------------*/
1303 
1304 static int build_dma_sg(const struct sk_buff *skb, struct urb *urb)
1305 {
1306 	unsigned num_sgs, total_len = 0;
1307 	int i, s = 0;
1308 
1309 	num_sgs = skb_shinfo(skb)->nr_frags + 1;
1310 	if (num_sgs == 1)
1311 		return 0;
1312 
1313 	/* reserve one for zero packet */
1314 	urb->sg = kmalloc_array(num_sgs + 1, sizeof(struct scatterlist),
1315 				GFP_ATOMIC);
1316 	if (!urb->sg)
1317 		return -ENOMEM;
1318 
1319 	urb->num_sgs = num_sgs;
1320 	sg_init_table(urb->sg, urb->num_sgs + 1);
1321 
1322 	sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb));
1323 	total_len += skb_headlen(skb);
1324 
1325 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1326 		struct skb_frag_struct *f = &skb_shinfo(skb)->frags[i];
1327 
1328 		total_len += skb_frag_size(f);
1329 		sg_set_page(&urb->sg[i + s], f->page.p, f->size,
1330 				f->page_offset);
1331 	}
1332 	urb->transfer_buffer_length = total_len;
1333 
1334 	return 1;
1335 }
1336 
1337 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1338 				     struct net_device *net)
1339 {
1340 	struct usbnet		*dev = netdev_priv(net);
1341 	unsigned int			length;
1342 	struct urb		*urb = NULL;
1343 	struct skb_data		*entry;
1344 	const struct driver_info *info = dev->driver_info;
1345 	unsigned long		flags;
1346 	int retval;
1347 
1348 	if (skb)
1349 		skb_tx_timestamp(skb);
1350 
1351 	// some devices want funky USB-level framing, for
1352 	// win32 driver (usually) and/or hardware quirks
1353 	if (info->tx_fixup) {
1354 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1355 		if (!skb) {
1356 			/* packet collected; minidriver waiting for more */
1357 			if (info->flags & FLAG_MULTI_PACKET)
1358 				goto not_drop;
1359 			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1360 			goto drop;
1361 		}
1362 	}
1363 
1364 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1365 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1366 		goto drop;
1367 	}
1368 
1369 	entry = (struct skb_data *) skb->cb;
1370 	entry->urb = urb;
1371 	entry->dev = dev;
1372 
1373 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1374 			skb->data, skb->len, tx_complete, skb);
1375 	if (dev->can_dma_sg) {
1376 		if (build_dma_sg(skb, urb) < 0)
1377 			goto drop;
1378 	}
1379 	length = urb->transfer_buffer_length;
1380 
1381 	/* don't assume the hardware handles USB_ZERO_PACKET
1382 	 * NOTE:  strictly conforming cdc-ether devices should expect
1383 	 * the ZLP here, but ignore the one-byte packet.
1384 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1385 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1386 	 * packet itself if needed.
1387 	 */
1388 	if (length % dev->maxpacket == 0) {
1389 		if (!(info->flags & FLAG_SEND_ZLP)) {
1390 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1391 				length++;
1392 				if (skb_tailroom(skb) && !urb->num_sgs) {
1393 					skb->data[skb->len] = 0;
1394 					__skb_put(skb, 1);
1395 				} else if (urb->num_sgs)
1396 					sg_set_buf(&urb->sg[urb->num_sgs++],
1397 							dev->padding_pkt, 1);
1398 			}
1399 		} else
1400 			urb->transfer_flags |= URB_ZERO_PACKET;
1401 	}
1402 	urb->transfer_buffer_length = length;
1403 
1404 	if (info->flags & FLAG_MULTI_PACKET) {
1405 		/* Driver has set number of packets and a length delta.
1406 		 * Calculate the complete length and ensure that it's
1407 		 * positive.
1408 		 */
1409 		entry->length += length;
1410 		if (WARN_ON_ONCE(entry->length <= 0))
1411 			entry->length = length;
1412 	} else {
1413 		usbnet_set_skb_tx_stats(skb, 1, length);
1414 	}
1415 
1416 	spin_lock_irqsave(&dev->txq.lock, flags);
1417 	retval = usb_autopm_get_interface_async(dev->intf);
1418 	if (retval < 0) {
1419 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1420 		goto drop;
1421 	}
1422 
1423 #ifdef CONFIG_PM
1424 	/* if this triggers the device is still a sleep */
1425 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1426 		/* transmission will be done in resume */
1427 		usb_anchor_urb(urb, &dev->deferred);
1428 		/* no use to process more packets */
1429 		netif_stop_queue(net);
1430 		usb_put_urb(urb);
1431 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1432 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1433 		goto deferred;
1434 	}
1435 #endif
1436 
1437 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1438 	case -EPIPE:
1439 		netif_stop_queue (net);
1440 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1441 		usb_autopm_put_interface_async(dev->intf);
1442 		break;
1443 	default:
1444 		usb_autopm_put_interface_async(dev->intf);
1445 		netif_dbg(dev, tx_err, dev->net,
1446 			  "tx: submit urb err %d\n", retval);
1447 		break;
1448 	case 0:
1449 		netif_trans_update(net);
1450 		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1451 		if (dev->txq.qlen >= TX_QLEN (dev))
1452 			netif_stop_queue (net);
1453 	}
1454 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1455 
1456 	if (retval) {
1457 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1458 drop:
1459 		dev->net->stats.tx_dropped++;
1460 not_drop:
1461 		if (skb)
1462 			dev_kfree_skb_any (skb);
1463 		if (urb) {
1464 			kfree(urb->sg);
1465 			usb_free_urb(urb);
1466 		}
1467 	} else
1468 		netif_dbg(dev, tx_queued, dev->net,
1469 			  "> tx, len %u, type 0x%x\n", length, skb->protocol);
1470 #ifdef CONFIG_PM
1471 deferred:
1472 #endif
1473 	return NETDEV_TX_OK;
1474 }
1475 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1476 
1477 static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1478 {
1479 	struct urb	*urb;
1480 	int		i;
1481 	int		ret = 0;
1482 
1483 	/* don't refill the queue all at once */
1484 	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1485 		urb = usb_alloc_urb(0, flags);
1486 		if (urb != NULL) {
1487 			ret = rx_submit(dev, urb, flags);
1488 			if (ret)
1489 				goto err;
1490 		} else {
1491 			ret = -ENOMEM;
1492 			goto err;
1493 		}
1494 	}
1495 err:
1496 	return ret;
1497 }
1498 
1499 /*-------------------------------------------------------------------------*/
1500 
1501 // tasklet (work deferred from completions, in_irq) or timer
1502 
1503 static void usbnet_bh (struct timer_list *t)
1504 {
1505 	struct usbnet		*dev = from_timer(dev, t, delay);
1506 	struct sk_buff		*skb;
1507 	struct skb_data		*entry;
1508 
1509 	while ((skb = skb_dequeue (&dev->done))) {
1510 		entry = (struct skb_data *) skb->cb;
1511 		switch (entry->state) {
1512 		case rx_done:
1513 			entry->state = rx_cleanup;
1514 			rx_process (dev, skb);
1515 			continue;
1516 		case tx_done:
1517 			kfree(entry->urb->sg);
1518 			/* fall through */
1519 		case rx_cleanup:
1520 			usb_free_urb (entry->urb);
1521 			dev_kfree_skb (skb);
1522 			continue;
1523 		default:
1524 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1525 		}
1526 	}
1527 
1528 	/* restart RX again after disabling due to high error rate */
1529 	clear_bit(EVENT_RX_KILL, &dev->flags);
1530 
1531 	/* waiting for all pending urbs to complete?
1532 	 * only then can we forgo submitting anew
1533 	 */
1534 	if (waitqueue_active(&dev->wait)) {
1535 		if (dev->txq.qlen + dev->rxq.qlen + dev->done.qlen == 0)
1536 			wake_up_all(&dev->wait);
1537 
1538 	// or are we maybe short a few urbs?
1539 	} else if (netif_running (dev->net) &&
1540 		   netif_device_present (dev->net) &&
1541 		   netif_carrier_ok(dev->net) &&
1542 		   !timer_pending(&dev->delay) &&
1543 		   !test_bit(EVENT_RX_PAUSED, &dev->flags) &&
1544 		   !test_bit(EVENT_RX_HALT, &dev->flags)) {
1545 		int	temp = dev->rxq.qlen;
1546 
1547 		if (temp < RX_QLEN(dev)) {
1548 			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1549 				return;
1550 			if (temp != dev->rxq.qlen)
1551 				netif_dbg(dev, link, dev->net,
1552 					  "rxqlen %d --> %d\n",
1553 					  temp, dev->rxq.qlen);
1554 			if (dev->rxq.qlen < RX_QLEN(dev))
1555 				tasklet_schedule (&dev->bh);
1556 		}
1557 		if (dev->txq.qlen < TX_QLEN (dev))
1558 			netif_wake_queue (dev->net);
1559 	}
1560 }
1561 
1562 
1563 /*-------------------------------------------------------------------------
1564  *
1565  * USB Device Driver support
1566  *
1567  *-------------------------------------------------------------------------*/
1568 
1569 // precondition: never called in_interrupt
1570 
1571 void usbnet_disconnect (struct usb_interface *intf)
1572 {
1573 	struct usbnet		*dev;
1574 	struct usb_device	*xdev;
1575 	struct net_device	*net;
1576 
1577 	dev = usb_get_intfdata(intf);
1578 	usb_set_intfdata(intf, NULL);
1579 	if (!dev)
1580 		return;
1581 
1582 	xdev = interface_to_usbdev (intf);
1583 
1584 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1585 		   intf->dev.driver->name,
1586 		   xdev->bus->bus_name, xdev->devpath,
1587 		   dev->driver_info->description);
1588 
1589 	net = dev->net;
1590 	unregister_netdev (net);
1591 
1592 	cancel_work_sync(&dev->kevent);
1593 
1594 	usb_scuttle_anchored_urbs(&dev->deferred);
1595 
1596 	if (dev->driver_info->unbind)
1597 		dev->driver_info->unbind (dev, intf);
1598 
1599 	usb_kill_urb(dev->interrupt);
1600 	usb_free_urb(dev->interrupt);
1601 	kfree(dev->padding_pkt);
1602 
1603 	free_percpu(dev->stats64);
1604 	free_netdev(net);
1605 }
1606 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1607 
1608 static const struct net_device_ops usbnet_netdev_ops = {
1609 	.ndo_open		= usbnet_open,
1610 	.ndo_stop		= usbnet_stop,
1611 	.ndo_start_xmit		= usbnet_start_xmit,
1612 	.ndo_tx_timeout		= usbnet_tx_timeout,
1613 	.ndo_set_rx_mode	= usbnet_set_rx_mode,
1614 	.ndo_change_mtu		= usbnet_change_mtu,
1615 	.ndo_get_stats64	= usbnet_get_stats64,
1616 	.ndo_set_mac_address 	= eth_mac_addr,
1617 	.ndo_validate_addr	= eth_validate_addr,
1618 };
1619 
1620 /*-------------------------------------------------------------------------*/
1621 
1622 // precondition: never called in_interrupt
1623 
1624 static struct device_type wlan_type = {
1625 	.name	= "wlan",
1626 };
1627 
1628 static struct device_type wwan_type = {
1629 	.name	= "wwan",
1630 };
1631 
1632 int
1633 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1634 {
1635 	struct usbnet			*dev;
1636 	struct net_device		*net;
1637 	struct usb_host_interface	*interface;
1638 	const struct driver_info	*info;
1639 	struct usb_device		*xdev;
1640 	int				status;
1641 	const char			*name;
1642 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1643 
1644 	/* usbnet already took usb runtime pm, so have to enable the feature
1645 	 * for usb interface, otherwise usb_autopm_get_interface may return
1646 	 * failure if RUNTIME_PM is enabled.
1647 	 */
1648 	if (!driver->supports_autosuspend) {
1649 		driver->supports_autosuspend = 1;
1650 		pm_runtime_enable(&udev->dev);
1651 	}
1652 
1653 	name = udev->dev.driver->name;
1654 	info = (const struct driver_info *) prod->driver_info;
1655 	if (!info) {
1656 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1657 		return -ENODEV;
1658 	}
1659 	xdev = interface_to_usbdev (udev);
1660 	interface = udev->cur_altsetting;
1661 
1662 	status = -ENOMEM;
1663 
1664 	// set up our own records
1665 	net = alloc_etherdev(sizeof(*dev));
1666 	if (!net)
1667 		goto out;
1668 
1669 	/* netdev_printk() needs this so do it as early as possible */
1670 	SET_NETDEV_DEV(net, &udev->dev);
1671 
1672 	dev = netdev_priv(net);
1673 	dev->udev = xdev;
1674 	dev->intf = udev;
1675 	dev->driver_info = info;
1676 	dev->driver_name = name;
1677 
1678 	dev->stats64 = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1679 	if (!dev->stats64)
1680 		goto out0;
1681 
1682 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1683 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1684 	init_waitqueue_head(&dev->wait);
1685 	skb_queue_head_init (&dev->rxq);
1686 	skb_queue_head_init (&dev->txq);
1687 	skb_queue_head_init (&dev->done);
1688 	skb_queue_head_init(&dev->rxq_pause);
1689 	dev->bh.func = (void (*)(unsigned long))usbnet_bh;
1690 	dev->bh.data = (unsigned long)&dev->delay;
1691 	INIT_WORK (&dev->kevent, usbnet_deferred_kevent);
1692 	init_usb_anchor(&dev->deferred);
1693 	timer_setup(&dev->delay, usbnet_bh, 0);
1694 	mutex_init (&dev->phy_mutex);
1695 	mutex_init(&dev->interrupt_mutex);
1696 	dev->interrupt_count = 0;
1697 
1698 	dev->net = net;
1699 	strcpy (net->name, "usb%d");
1700 	memcpy (net->dev_addr, node_id, sizeof node_id);
1701 
1702 	/* rx and tx sides can use different message sizes;
1703 	 * bind() should set rx_urb_size in that case.
1704 	 */
1705 	dev->hard_mtu = net->mtu + net->hard_header_len;
1706 	net->min_mtu = 0;
1707 	net->max_mtu = ETH_MAX_MTU;
1708 
1709 	net->netdev_ops = &usbnet_netdev_ops;
1710 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1711 	net->ethtool_ops = &usbnet_ethtool_ops;
1712 
1713 	// allow device-specific bind/init procedures
1714 	// NOTE net->name still not usable ...
1715 	if (info->bind) {
1716 		status = info->bind (dev, udev);
1717 		if (status < 0)
1718 			goto out1;
1719 
1720 		// heuristic:  "usb%d" for links we know are two-host,
1721 		// else "eth%d" when there's reasonable doubt.  userspace
1722 		// can rename the link if it knows better.
1723 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1724 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1725 		     (net->dev_addr [0] & 0x02) == 0))
1726 			strcpy (net->name, "eth%d");
1727 		/* WLAN devices should always be named "wlan%d" */
1728 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1729 			strcpy(net->name, "wlan%d");
1730 		/* WWAN devices should always be named "wwan%d" */
1731 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1732 			strcpy(net->name, "wwan%d");
1733 
1734 		/* devices that cannot do ARP */
1735 		if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1736 			net->flags |= IFF_NOARP;
1737 
1738 		/* maybe the remote can't receive an Ethernet MTU */
1739 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1740 			net->mtu = dev->hard_mtu - net->hard_header_len;
1741 	} else if (!info->in || !info->out)
1742 		status = usbnet_get_endpoints (dev, udev);
1743 	else {
1744 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1745 		dev->out = usb_sndbulkpipe (xdev, info->out);
1746 		if (!(info->flags & FLAG_NO_SETINT))
1747 			status = usb_set_interface (xdev,
1748 				interface->desc.bInterfaceNumber,
1749 				interface->desc.bAlternateSetting);
1750 		else
1751 			status = 0;
1752 
1753 	}
1754 	if (status >= 0 && dev->status)
1755 		status = init_status (dev, udev);
1756 	if (status < 0)
1757 		goto out3;
1758 
1759 	if (!dev->rx_urb_size)
1760 		dev->rx_urb_size = dev->hard_mtu;
1761 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1762 
1763 	/* let userspace know we have a random address */
1764 	if (ether_addr_equal(net->dev_addr, node_id))
1765 		net->addr_assign_type = NET_ADDR_RANDOM;
1766 
1767 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1768 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1769 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1770 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1771 
1772 	/* initialize max rx_qlen and tx_qlen */
1773 	usbnet_update_max_qlen(dev);
1774 
1775 	if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&
1776 		!(info->flags & FLAG_MULTI_PACKET)) {
1777 		dev->padding_pkt = kzalloc(1, GFP_KERNEL);
1778 		if (!dev->padding_pkt) {
1779 			status = -ENOMEM;
1780 			goto out4;
1781 		}
1782 	}
1783 
1784 	status = register_netdev (net);
1785 	if (status)
1786 		goto out5;
1787 	netif_info(dev, probe, dev->net,
1788 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1789 		   udev->dev.driver->name,
1790 		   xdev->bus->bus_name, xdev->devpath,
1791 		   dev->driver_info->description,
1792 		   net->dev_addr);
1793 
1794 	// ok, it's ready to go.
1795 	usb_set_intfdata (udev, dev);
1796 
1797 	netif_device_attach (net);
1798 
1799 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1800 		usbnet_link_change(dev, 0, 0);
1801 
1802 	return 0;
1803 
1804 out5:
1805 	kfree(dev->padding_pkt);
1806 out4:
1807 	usb_free_urb(dev->interrupt);
1808 out3:
1809 	if (info->unbind)
1810 		info->unbind (dev, udev);
1811 out1:
1812 	/* subdrivers must undo all they did in bind() if they
1813 	 * fail it, but we may fail later and a deferred kevent
1814 	 * may trigger an error resubmitting itself and, worse,
1815 	 * schedule a timer. So we kill it all just in case.
1816 	 */
1817 	cancel_work_sync(&dev->kevent);
1818 	del_timer_sync(&dev->delay);
1819 	free_percpu(dev->stats64);
1820 out0:
1821 	free_netdev(net);
1822 out:
1823 	return status;
1824 }
1825 EXPORT_SYMBOL_GPL(usbnet_probe);
1826 
1827 /*-------------------------------------------------------------------------*/
1828 
1829 /*
1830  * suspend the whole driver as soon as the first interface is suspended
1831  * resume only when the last interface is resumed
1832  */
1833 
1834 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1835 {
1836 	struct usbnet		*dev = usb_get_intfdata(intf);
1837 
1838 	if (!dev->suspend_count++) {
1839 		spin_lock_irq(&dev->txq.lock);
1840 		/* don't autosuspend while transmitting */
1841 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1842 			dev->suspend_count--;
1843 			spin_unlock_irq(&dev->txq.lock);
1844 			return -EBUSY;
1845 		} else {
1846 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1847 			spin_unlock_irq(&dev->txq.lock);
1848 		}
1849 		/*
1850 		 * accelerate emptying of the rx and queues, to avoid
1851 		 * having everything error out.
1852 		 */
1853 		netif_device_detach (dev->net);
1854 		usbnet_terminate_urbs(dev);
1855 		__usbnet_status_stop_force(dev);
1856 
1857 		/*
1858 		 * reattach so runtime management can use and
1859 		 * wake the device
1860 		 */
1861 		netif_device_attach (dev->net);
1862 	}
1863 	return 0;
1864 }
1865 EXPORT_SYMBOL_GPL(usbnet_suspend);
1866 
1867 int usbnet_resume (struct usb_interface *intf)
1868 {
1869 	struct usbnet		*dev = usb_get_intfdata(intf);
1870 	struct sk_buff          *skb;
1871 	struct urb              *res;
1872 	int                     retval;
1873 
1874 	if (!--dev->suspend_count) {
1875 		/* resume interrupt URB if it was previously submitted */
1876 		__usbnet_status_start_force(dev, GFP_NOIO);
1877 
1878 		spin_lock_irq(&dev->txq.lock);
1879 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1880 
1881 			skb = (struct sk_buff *)res->context;
1882 			retval = usb_submit_urb(res, GFP_ATOMIC);
1883 			if (retval < 0) {
1884 				dev_kfree_skb_any(skb);
1885 				kfree(res->sg);
1886 				usb_free_urb(res);
1887 				usb_autopm_put_interface_async(dev->intf);
1888 			} else {
1889 				netif_trans_update(dev->net);
1890 				__skb_queue_tail(&dev->txq, skb);
1891 			}
1892 		}
1893 
1894 		smp_mb();
1895 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1896 		spin_unlock_irq(&dev->txq.lock);
1897 
1898 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1899 			/* handle remote wakeup ASAP
1900 			 * we cannot race against stop
1901 			 */
1902 			if (netif_device_present(dev->net) &&
1903 				!timer_pending(&dev->delay) &&
1904 				!test_bit(EVENT_RX_HALT, &dev->flags))
1905 					rx_alloc_submit(dev, GFP_NOIO);
1906 
1907 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1908 				netif_tx_wake_all_queues(dev->net);
1909 			tasklet_schedule (&dev->bh);
1910 		}
1911 	}
1912 
1913 	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1914 		usb_autopm_get_interface_no_resume(intf);
1915 
1916 	return 0;
1917 }
1918 EXPORT_SYMBOL_GPL(usbnet_resume);
1919 
1920 /*
1921  * Either a subdriver implements manage_power, then it is assumed to always
1922  * be ready to be suspended or it reports the readiness to be suspended
1923  * explicitly
1924  */
1925 void usbnet_device_suggests_idle(struct usbnet *dev)
1926 {
1927 	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1928 		dev->intf->needs_remote_wakeup = 1;
1929 		usb_autopm_put_interface_async(dev->intf);
1930 	}
1931 }
1932 EXPORT_SYMBOL(usbnet_device_suggests_idle);
1933 
1934 /*
1935  * For devices that can do without special commands
1936  */
1937 int usbnet_manage_power(struct usbnet *dev, int on)
1938 {
1939 	dev->intf->needs_remote_wakeup = on;
1940 	return 0;
1941 }
1942 EXPORT_SYMBOL(usbnet_manage_power);
1943 
1944 void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
1945 {
1946 	/* update link after link is reseted */
1947 	if (link && !need_reset)
1948 		netif_carrier_on(dev->net);
1949 	else
1950 		netif_carrier_off(dev->net);
1951 
1952 	if (need_reset && link)
1953 		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
1954 	else
1955 		usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
1956 }
1957 EXPORT_SYMBOL(usbnet_link_change);
1958 
1959 /*-------------------------------------------------------------------------*/
1960 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1961 			     u16 value, u16 index, void *data, u16 size)
1962 {
1963 	void *buf = NULL;
1964 	int err = -ENOMEM;
1965 
1966 	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
1967 		   " value=0x%04x index=0x%04x size=%d\n",
1968 		   cmd, reqtype, value, index, size);
1969 
1970 	if (size) {
1971 		buf = kmalloc(size, GFP_KERNEL);
1972 		if (!buf)
1973 			goto out;
1974 	}
1975 
1976 	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
1977 			      cmd, reqtype, value, index, buf, size,
1978 			      USB_CTRL_GET_TIMEOUT);
1979 	if (err > 0 && err <= size) {
1980         if (data)
1981             memcpy(data, buf, err);
1982         else
1983             netdev_dbg(dev->net,
1984                 "Huh? Data requested but thrown away.\n");
1985     }
1986 	kfree(buf);
1987 out:
1988 	return err;
1989 }
1990 
1991 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1992 			      u16 value, u16 index, const void *data,
1993 			      u16 size)
1994 {
1995 	void *buf = NULL;
1996 	int err = -ENOMEM;
1997 
1998 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
1999 		   " value=0x%04x index=0x%04x size=%d\n",
2000 		   cmd, reqtype, value, index, size);
2001 
2002 	if (data) {
2003 		buf = kmemdup(data, size, GFP_KERNEL);
2004 		if (!buf)
2005 			goto out;
2006 	} else {
2007         if (size) {
2008             WARN_ON_ONCE(1);
2009             err = -EINVAL;
2010             goto out;
2011         }
2012     }
2013 
2014 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
2015 			      cmd, reqtype, value, index, buf, size,
2016 			      USB_CTRL_SET_TIMEOUT);
2017 	kfree(buf);
2018 
2019 out:
2020 	return err;
2021 }
2022 
2023 /*
2024  * The function can't be called inside suspend/resume callback,
2025  * otherwise deadlock will be caused.
2026  */
2027 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2028 		    u16 value, u16 index, void *data, u16 size)
2029 {
2030 	int ret;
2031 
2032 	if (usb_autopm_get_interface(dev->intf) < 0)
2033 		return -ENODEV;
2034 	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2035 				data, size);
2036 	usb_autopm_put_interface(dev->intf);
2037 	return ret;
2038 }
2039 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
2040 
2041 /*
2042  * The function can't be called inside suspend/resume callback,
2043  * otherwise deadlock will be caused.
2044  */
2045 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2046 		     u16 value, u16 index, const void *data, u16 size)
2047 {
2048 	int ret;
2049 
2050 	if (usb_autopm_get_interface(dev->intf) < 0)
2051 		return -ENODEV;
2052 	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2053 				 data, size);
2054 	usb_autopm_put_interface(dev->intf);
2055 	return ret;
2056 }
2057 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
2058 
2059 /*
2060  * The function can be called inside suspend/resume callback safely
2061  * and should only be called by suspend/resume callback generally.
2062  */
2063 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2064 			  u16 value, u16 index, void *data, u16 size)
2065 {
2066 	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2067 				 data, size);
2068 }
2069 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
2070 
2071 /*
2072  * The function can be called inside suspend/resume callback safely
2073  * and should only be called by suspend/resume callback generally.
2074  */
2075 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2076 			  u16 value, u16 index, const void *data,
2077 			  u16 size)
2078 {
2079 	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2080 				  data, size);
2081 }
2082 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
2083 
2084 static void usbnet_async_cmd_cb(struct urb *urb)
2085 {
2086 	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
2087 	int status = urb->status;
2088 
2089 	if (status < 0)
2090 		dev_dbg(&urb->dev->dev, "%s failed with %d",
2091 			__func__, status);
2092 
2093 	kfree(req);
2094 	usb_free_urb(urb);
2095 }
2096 
2097 /*
2098  * The caller must make sure that device can't be put into suspend
2099  * state until the control URB completes.
2100  */
2101 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
2102 			   u16 value, u16 index, const void *data, u16 size)
2103 {
2104 	struct usb_ctrlrequest *req = NULL;
2105 	struct urb *urb;
2106 	int err = -ENOMEM;
2107 	void *buf = NULL;
2108 
2109 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2110 		   " value=0x%04x index=0x%04x size=%d\n",
2111 		   cmd, reqtype, value, index, size);
2112 
2113 	urb = usb_alloc_urb(0, GFP_ATOMIC);
2114 	if (!urb)
2115 		goto fail;
2116 
2117 	if (data) {
2118 		buf = kmemdup(data, size, GFP_ATOMIC);
2119 		if (!buf) {
2120 			netdev_err(dev->net, "Error allocating buffer"
2121 				   " in %s!\n", __func__);
2122 			goto fail_free;
2123 		}
2124 	}
2125 
2126 	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
2127 	if (!req)
2128 		goto fail_free_buf;
2129 
2130 	req->bRequestType = reqtype;
2131 	req->bRequest = cmd;
2132 	req->wValue = cpu_to_le16(value);
2133 	req->wIndex = cpu_to_le16(index);
2134 	req->wLength = cpu_to_le16(size);
2135 
2136 	usb_fill_control_urb(urb, dev->udev,
2137 			     usb_sndctrlpipe(dev->udev, 0),
2138 			     (void *)req, buf, size,
2139 			     usbnet_async_cmd_cb, req);
2140 	urb->transfer_flags |= URB_FREE_BUFFER;
2141 
2142 	err = usb_submit_urb(urb, GFP_ATOMIC);
2143 	if (err < 0) {
2144 		netdev_err(dev->net, "Error submitting the control"
2145 			   " message: status=%d\n", err);
2146 		goto fail_free;
2147 	}
2148 	return 0;
2149 
2150 fail_free_buf:
2151 	kfree(buf);
2152 fail_free:
2153 	kfree(req);
2154 	usb_free_urb(urb);
2155 fail:
2156 	return err;
2157 
2158 }
2159 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
2160 /*-------------------------------------------------------------------------*/
2161 
2162 static int __init usbnet_init(void)
2163 {
2164 	/* Compiler should optimize this out. */
2165 	BUILD_BUG_ON(
2166 		FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
2167 
2168 	eth_random_addr(node_id);
2169 	return 0;
2170 }
2171 module_init(usbnet_init);
2172 
2173 static void __exit usbnet_exit(void)
2174 {
2175 }
2176 module_exit(usbnet_exit);
2177 
2178 MODULE_AUTHOR("David Brownell");
2179 MODULE_DESCRIPTION("USB network driver framework");
2180 MODULE_LICENSE("GPL");
2181