xref: /openbmc/linux/drivers/net/usb/usbnet.c (revision b9df3997)
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 
104 			/* ignore endpoints which cannot transfer data */
105 			if (!usb_endpoint_maxp(&e->desc))
106 				continue;
107 
108 			switch (e->desc.bmAttributes) {
109 			case USB_ENDPOINT_XFER_INT:
110 				if (!usb_endpoint_dir_in(&e->desc))
111 					continue;
112 				intr = 1;
113 				/* FALLTHROUGH */
114 			case USB_ENDPOINT_XFER_BULK:
115 				break;
116 			default:
117 				continue;
118 			}
119 			if (usb_endpoint_dir_in(&e->desc)) {
120 				if (!intr && !in)
121 					in = e;
122 				else if (intr && !status)
123 					status = e;
124 			} else {
125 				if (!out)
126 					out = e;
127 			}
128 		}
129 		if (in && out)
130 			break;
131 	}
132 	if (!alt || !in || !out)
133 		return -EINVAL;
134 
135 	if (alt->desc.bAlternateSetting != 0 ||
136 	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
137 		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
138 				alt->desc.bAlternateSetting);
139 		if (tmp < 0)
140 			return tmp;
141 	}
142 
143 	dev->in = usb_rcvbulkpipe (dev->udev,
144 			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
145 	dev->out = usb_sndbulkpipe (dev->udev,
146 			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
147 	dev->status = status;
148 	return 0;
149 }
150 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
151 
152 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
153 {
154 	int 		tmp = -1, ret;
155 	unsigned char	buf [13];
156 
157 	ret = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
158 	if (ret == 12)
159 		tmp = hex2bin(dev->net->dev_addr, buf, 6);
160 	if (tmp < 0) {
161 		dev_dbg(&dev->udev->dev,
162 			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
163 		if (ret >= 0)
164 			ret = -EINVAL;
165 		return ret;
166 	}
167 	return 0;
168 }
169 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
170 
171 static void intr_complete (struct urb *urb)
172 {
173 	struct usbnet	*dev = urb->context;
174 	int		status = urb->status;
175 
176 	switch (status) {
177 	/* success */
178 	case 0:
179 		dev->driver_info->status(dev, urb);
180 		break;
181 
182 	/* software-driven interface shutdown */
183 	case -ENOENT:		/* urb killed */
184 	case -ESHUTDOWN:	/* hardware gone */
185 		netif_dbg(dev, ifdown, dev->net,
186 			  "intr shutdown, code %d\n", status);
187 		return;
188 
189 	/* NOTE:  not throttling like RX/TX, since this endpoint
190 	 * already polls infrequently
191 	 */
192 	default:
193 		netdev_dbg(dev->net, "intr status %d\n", status);
194 		break;
195 	}
196 
197 	status = usb_submit_urb (urb, GFP_ATOMIC);
198 	if (status != 0)
199 		netif_err(dev, timer, dev->net,
200 			  "intr resubmit --> %d\n", status);
201 }
202 
203 static int init_status (struct usbnet *dev, struct usb_interface *intf)
204 {
205 	char		*buf = NULL;
206 	unsigned	pipe = 0;
207 	unsigned	maxp;
208 	unsigned	period;
209 
210 	if (!dev->driver_info->status)
211 		return 0;
212 
213 	pipe = usb_rcvintpipe (dev->udev,
214 			dev->status->desc.bEndpointAddress
215 				& USB_ENDPOINT_NUMBER_MASK);
216 	maxp = usb_maxpacket (dev->udev, pipe, 0);
217 
218 	/* avoid 1 msec chatter:  min 8 msec poll rate */
219 	period = max ((int) dev->status->desc.bInterval,
220 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
221 
222 	buf = kmalloc (maxp, GFP_KERNEL);
223 	if (buf) {
224 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
225 		if (!dev->interrupt) {
226 			kfree (buf);
227 			return -ENOMEM;
228 		} else {
229 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
230 				buf, maxp, intr_complete, dev, period);
231 			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
232 			dev_dbg(&intf->dev,
233 				"status ep%din, %d bytes period %d\n",
234 				usb_pipeendpoint(pipe), maxp, period);
235 		}
236 	}
237 	return 0;
238 }
239 
240 /* Submit the interrupt URB if not previously submitted, increasing refcount */
241 int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
242 {
243 	int ret = 0;
244 
245 	WARN_ON_ONCE(dev->interrupt == NULL);
246 	if (dev->interrupt) {
247 		mutex_lock(&dev->interrupt_mutex);
248 
249 		if (++dev->interrupt_count == 1)
250 			ret = usb_submit_urb(dev->interrupt, mem_flags);
251 
252 		dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
253 			dev->interrupt_count);
254 		mutex_unlock(&dev->interrupt_mutex);
255 	}
256 	return ret;
257 }
258 EXPORT_SYMBOL_GPL(usbnet_status_start);
259 
260 /* For resume; submit interrupt URB if previously submitted */
261 static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
262 {
263 	int ret = 0;
264 
265 	mutex_lock(&dev->interrupt_mutex);
266 	if (dev->interrupt_count) {
267 		ret = usb_submit_urb(dev->interrupt, mem_flags);
268 		dev_dbg(&dev->udev->dev,
269 			"submitted interrupt URB for resume\n");
270 	}
271 	mutex_unlock(&dev->interrupt_mutex);
272 	return ret;
273 }
274 
275 /* Kill the interrupt URB if all submitters want it killed */
276 void usbnet_status_stop(struct usbnet *dev)
277 {
278 	if (dev->interrupt) {
279 		mutex_lock(&dev->interrupt_mutex);
280 		WARN_ON(dev->interrupt_count == 0);
281 
282 		if (dev->interrupt_count && --dev->interrupt_count == 0)
283 			usb_kill_urb(dev->interrupt);
284 
285 		dev_dbg(&dev->udev->dev,
286 			"decremented interrupt URB count to %d\n",
287 			dev->interrupt_count);
288 		mutex_unlock(&dev->interrupt_mutex);
289 	}
290 }
291 EXPORT_SYMBOL_GPL(usbnet_status_stop);
292 
293 /* For suspend; always kill interrupt URB */
294 static void __usbnet_status_stop_force(struct usbnet *dev)
295 {
296 	if (dev->interrupt) {
297 		mutex_lock(&dev->interrupt_mutex);
298 		usb_kill_urb(dev->interrupt);
299 		dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
300 		mutex_unlock(&dev->interrupt_mutex);
301 	}
302 }
303 
304 /* Passes this packet up the stack, updating its accounting.
305  * Some link protocols batch packets, so their rx_fixup paths
306  * can return clones as well as just modify the original skb.
307  */
308 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
309 {
310 	struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->stats64);
311 	unsigned long flags;
312 	int	status;
313 
314 	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
315 		skb_queue_tail(&dev->rxq_pause, skb);
316 		return;
317 	}
318 
319 	/* only update if unset to allow minidriver rx_fixup override */
320 	if (skb->protocol == 0)
321 		skb->protocol = eth_type_trans (skb, dev->net);
322 
323 	flags = u64_stats_update_begin_irqsave(&stats64->syncp);
324 	stats64->rx_packets++;
325 	stats64->rx_bytes += skb->len;
326 	u64_stats_update_end_irqrestore(&stats64->syncp, flags);
327 
328 	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
329 		  skb->len + sizeof (struct ethhdr), skb->protocol);
330 	memset (skb->cb, 0, sizeof (struct skb_data));
331 
332 	if (skb_defer_rx_timestamp(skb))
333 		return;
334 
335 	status = netif_rx (skb);
336 	if (status != NET_RX_SUCCESS)
337 		netif_dbg(dev, rx_err, dev->net,
338 			  "netif_rx status %d\n", status);
339 }
340 EXPORT_SYMBOL_GPL(usbnet_skb_return);
341 
342 /* must be called if hard_mtu or rx_urb_size changed */
343 void usbnet_update_max_qlen(struct usbnet *dev)
344 {
345 	enum usb_device_speed speed = dev->udev->speed;
346 
347 	if (!dev->rx_urb_size || !dev->hard_mtu)
348 		goto insanity;
349 	switch (speed) {
350 	case USB_SPEED_HIGH:
351 		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
352 		dev->tx_qlen = MAX_QUEUE_MEMORY / dev->hard_mtu;
353 		break;
354 	case USB_SPEED_SUPER:
355 	case USB_SPEED_SUPER_PLUS:
356 		/*
357 		 * Not take default 5ms qlen for super speed HC to
358 		 * save memory, and iperf tests show 2.5ms qlen can
359 		 * work well
360 		 */
361 		dev->rx_qlen = 5 * MAX_QUEUE_MEMORY / dev->rx_urb_size;
362 		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
363 		break;
364 	default:
365 insanity:
366 		dev->rx_qlen = dev->tx_qlen = 4;
367 	}
368 }
369 EXPORT_SYMBOL_GPL(usbnet_update_max_qlen);
370 
371 
372 /*-------------------------------------------------------------------------
373  *
374  * Network Device Driver (peer link to "Host Device", from USB host)
375  *
376  *-------------------------------------------------------------------------*/
377 
378 int usbnet_change_mtu (struct net_device *net, int new_mtu)
379 {
380 	struct usbnet	*dev = netdev_priv(net);
381 	int		ll_mtu = new_mtu + net->hard_header_len;
382 	int		old_hard_mtu = dev->hard_mtu;
383 	int		old_rx_urb_size = dev->rx_urb_size;
384 
385 	// no second zero-length packet read wanted after mtu-sized packets
386 	if ((ll_mtu % dev->maxpacket) == 0)
387 		return -EDOM;
388 	net->mtu = new_mtu;
389 
390 	dev->hard_mtu = net->mtu + net->hard_header_len;
391 	if (dev->rx_urb_size == old_hard_mtu) {
392 		dev->rx_urb_size = dev->hard_mtu;
393 		if (dev->rx_urb_size > old_rx_urb_size) {
394 			usbnet_pause_rx(dev);
395 			usbnet_unlink_rx_urbs(dev);
396 			usbnet_resume_rx(dev);
397 		}
398 	}
399 
400 	/* max qlen depend on hard_mtu and rx_urb_size */
401 	usbnet_update_max_qlen(dev);
402 
403 	return 0;
404 }
405 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
406 
407 /* The caller must hold list->lock */
408 static void __usbnet_queue_skb(struct sk_buff_head *list,
409 			struct sk_buff *newsk, enum skb_state state)
410 {
411 	struct skb_data *entry = (struct skb_data *) newsk->cb;
412 
413 	__skb_queue_tail(list, newsk);
414 	entry->state = state;
415 }
416 
417 /*-------------------------------------------------------------------------*/
418 
419 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
420  * completion callbacks.  2.5 should have fixed those bugs...
421  */
422 
423 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
424 		struct sk_buff_head *list, enum skb_state state)
425 {
426 	unsigned long		flags;
427 	enum skb_state 		old_state;
428 	struct skb_data *entry = (struct skb_data *) skb->cb;
429 
430 	spin_lock_irqsave(&list->lock, flags);
431 	old_state = entry->state;
432 	entry->state = state;
433 	__skb_unlink(skb, list);
434 
435 	/* defer_bh() is never called with list == &dev->done.
436 	 * spin_lock_nested() tells lockdep that it is OK to take
437 	 * dev->done.lock here with list->lock held.
438 	 */
439 	spin_lock_nested(&dev->done.lock, SINGLE_DEPTH_NESTING);
440 
441 	__skb_queue_tail(&dev->done, skb);
442 	if (dev->done.qlen == 1)
443 		tasklet_schedule(&dev->bh);
444 	spin_unlock(&dev->done.lock);
445 	spin_unlock_irqrestore(&list->lock, flags);
446 	return old_state;
447 }
448 
449 /* some work can't be done in tasklets, so we use keventd
450  *
451  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
452  * but tasklet_schedule() doesn't.  hope the failure is rare.
453  */
454 void usbnet_defer_kevent (struct usbnet *dev, int work)
455 {
456 	set_bit (work, &dev->flags);
457 	if (!schedule_work (&dev->kevent))
458 		netdev_dbg(dev->net, "kevent %d may have been dropped\n", work);
459 	else
460 		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
461 }
462 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
463 
464 /*-------------------------------------------------------------------------*/
465 
466 static void rx_complete (struct urb *urb);
467 
468 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
469 {
470 	struct sk_buff		*skb;
471 	struct skb_data		*entry;
472 	int			retval = 0;
473 	unsigned long		lockflags;
474 	size_t			size = dev->rx_urb_size;
475 
476 	/* prevent rx skb allocation when error ratio is high */
477 	if (test_bit(EVENT_RX_KILL, &dev->flags)) {
478 		usb_free_urb(urb);
479 		return -ENOLINK;
480 	}
481 
482 	if (test_bit(EVENT_NO_IP_ALIGN, &dev->flags))
483 		skb = __netdev_alloc_skb(dev->net, size, flags);
484 	else
485 		skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
486 	if (!skb) {
487 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
488 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
489 		usb_free_urb (urb);
490 		return -ENOMEM;
491 	}
492 
493 	entry = (struct skb_data *) skb->cb;
494 	entry->urb = urb;
495 	entry->dev = dev;
496 	entry->length = 0;
497 
498 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
499 		skb->data, size, rx_complete, skb);
500 
501 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
502 
503 	if (netif_running (dev->net) &&
504 	    netif_device_present (dev->net) &&
505 	    test_bit(EVENT_DEV_OPEN, &dev->flags) &&
506 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
507 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
508 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
509 		case -EPIPE:
510 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
511 			break;
512 		case -ENOMEM:
513 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
514 			break;
515 		case -ENODEV:
516 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
517 			netif_device_detach (dev->net);
518 			break;
519 		case -EHOSTUNREACH:
520 			retval = -ENOLINK;
521 			break;
522 		default:
523 			netif_dbg(dev, rx_err, dev->net,
524 				  "rx submit, %d\n", retval);
525 			tasklet_schedule (&dev->bh);
526 			break;
527 		case 0:
528 			__usbnet_queue_skb(&dev->rxq, skb, rx_start);
529 		}
530 	} else {
531 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
532 		retval = -ENOLINK;
533 	}
534 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
535 	if (retval) {
536 		dev_kfree_skb_any (skb);
537 		usb_free_urb (urb);
538 	}
539 	return retval;
540 }
541 
542 
543 /*-------------------------------------------------------------------------*/
544 
545 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
546 {
547 	if (dev->driver_info->rx_fixup &&
548 	    !dev->driver_info->rx_fixup (dev, skb)) {
549 		/* With RX_ASSEMBLE, rx_fixup() must update counters */
550 		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
551 			dev->net->stats.rx_errors++;
552 		goto done;
553 	}
554 	// else network stack removes extra byte if we forced a short packet
555 
556 	/* all data was already cloned from skb inside the driver */
557 	if (dev->driver_info->flags & FLAG_MULTI_PACKET)
558 		goto done;
559 
560 	if (skb->len < ETH_HLEN) {
561 		dev->net->stats.rx_errors++;
562 		dev->net->stats.rx_length_errors++;
563 		netif_dbg(dev, rx_err, dev->net, "rx length %d\n", skb->len);
564 	} else {
565 		usbnet_skb_return(dev, skb);
566 		return;
567 	}
568 
569 done:
570 	skb_queue_tail(&dev->done, skb);
571 }
572 
573 /*-------------------------------------------------------------------------*/
574 
575 static void rx_complete (struct urb *urb)
576 {
577 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
578 	struct skb_data		*entry = (struct skb_data *) skb->cb;
579 	struct usbnet		*dev = entry->dev;
580 	int			urb_status = urb->status;
581 	enum skb_state		state;
582 
583 	skb_put (skb, urb->actual_length);
584 	state = rx_done;
585 	entry->urb = NULL;
586 
587 	switch (urb_status) {
588 	/* success */
589 	case 0:
590 		break;
591 
592 	/* stalls need manual reset. this is rare ... except that
593 	 * when going through USB 2.0 TTs, unplug appears this way.
594 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
595 	 * storm, recovering as needed.
596 	 */
597 	case -EPIPE:
598 		dev->net->stats.rx_errors++;
599 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
600 		// FALLTHROUGH
601 
602 	/* software-driven interface shutdown */
603 	case -ECONNRESET:		/* async unlink */
604 	case -ESHUTDOWN:		/* hardware gone */
605 		netif_dbg(dev, ifdown, dev->net,
606 			  "rx shutdown, code %d\n", urb_status);
607 		goto block;
608 
609 	/* we get controller i/o faults during hub_wq disconnect() delays.
610 	 * throttle down resubmits, to avoid log floods; just temporarily,
611 	 * so we still recover when the fault isn't a hub_wq delay.
612 	 */
613 	case -EPROTO:
614 	case -ETIME:
615 	case -EILSEQ:
616 		dev->net->stats.rx_errors++;
617 		if (!timer_pending (&dev->delay)) {
618 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
619 			netif_dbg(dev, link, dev->net,
620 				  "rx throttle %d\n", urb_status);
621 		}
622 block:
623 		state = rx_cleanup;
624 		entry->urb = urb;
625 		urb = NULL;
626 		break;
627 
628 	/* data overrun ... flush fifo? */
629 	case -EOVERFLOW:
630 		dev->net->stats.rx_over_errors++;
631 		// FALLTHROUGH
632 
633 	default:
634 		state = rx_cleanup;
635 		dev->net->stats.rx_errors++;
636 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
637 		break;
638 	}
639 
640 	/* stop rx if packet error rate is high */
641 	if (++dev->pkt_cnt > 30) {
642 		dev->pkt_cnt = 0;
643 		dev->pkt_err = 0;
644 	} else {
645 		if (state == rx_cleanup)
646 			dev->pkt_err++;
647 		if (dev->pkt_err > 20)
648 			set_bit(EVENT_RX_KILL, &dev->flags);
649 	}
650 
651 	state = defer_bh(dev, skb, &dev->rxq, state);
652 
653 	if (urb) {
654 		if (netif_running (dev->net) &&
655 		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
656 		    state != unlink_start) {
657 			rx_submit (dev, urb, GFP_ATOMIC);
658 			usb_mark_last_busy(dev->udev);
659 			return;
660 		}
661 		usb_free_urb (urb);
662 	}
663 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
664 }
665 
666 /*-------------------------------------------------------------------------*/
667 void usbnet_pause_rx(struct usbnet *dev)
668 {
669 	set_bit(EVENT_RX_PAUSED, &dev->flags);
670 
671 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
672 }
673 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
674 
675 void usbnet_resume_rx(struct usbnet *dev)
676 {
677 	struct sk_buff *skb;
678 	int num = 0;
679 
680 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
681 
682 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
683 		usbnet_skb_return(dev, skb);
684 		num++;
685 	}
686 
687 	tasklet_schedule(&dev->bh);
688 
689 	netif_dbg(dev, rx_status, dev->net,
690 		  "paused rx queue disabled, %d skbs requeued\n", num);
691 }
692 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
693 
694 void usbnet_purge_paused_rxq(struct usbnet *dev)
695 {
696 	skb_queue_purge(&dev->rxq_pause);
697 }
698 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
699 
700 /*-------------------------------------------------------------------------*/
701 
702 // unlink pending rx/tx; completion handlers do all other cleanup
703 
704 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
705 {
706 	unsigned long		flags;
707 	struct sk_buff		*skb;
708 	int			count = 0;
709 
710 	spin_lock_irqsave (&q->lock, flags);
711 	while (!skb_queue_empty(q)) {
712 		struct skb_data		*entry;
713 		struct urb		*urb;
714 		int			retval;
715 
716 		skb_queue_walk(q, skb) {
717 			entry = (struct skb_data *) skb->cb;
718 			if (entry->state != unlink_start)
719 				goto found;
720 		}
721 		break;
722 found:
723 		entry->state = unlink_start;
724 		urb = entry->urb;
725 
726 		/*
727 		 * Get reference count of the URB to avoid it to be
728 		 * freed during usb_unlink_urb, which may trigger
729 		 * use-after-free problem inside usb_unlink_urb since
730 		 * usb_unlink_urb is always racing with .complete
731 		 * handler(include defer_bh).
732 		 */
733 		usb_get_urb(urb);
734 		spin_unlock_irqrestore(&q->lock, flags);
735 		// during some PM-driven resume scenarios,
736 		// these (async) unlinks complete immediately
737 		retval = usb_unlink_urb (urb);
738 		if (retval != -EINPROGRESS && retval != 0)
739 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
740 		else
741 			count++;
742 		usb_put_urb(urb);
743 		spin_lock_irqsave(&q->lock, flags);
744 	}
745 	spin_unlock_irqrestore (&q->lock, flags);
746 	return count;
747 }
748 
749 // Flush all pending rx urbs
750 // minidrivers may need to do this when the MTU changes
751 
752 void usbnet_unlink_rx_urbs(struct usbnet *dev)
753 {
754 	if (netif_running(dev->net)) {
755 		(void) unlink_urbs (dev, &dev->rxq);
756 		tasklet_schedule(&dev->bh);
757 	}
758 }
759 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
760 
761 /*-------------------------------------------------------------------------*/
762 
763 static void wait_skb_queue_empty(struct sk_buff_head *q)
764 {
765 	unsigned long flags;
766 
767 	spin_lock_irqsave(&q->lock, flags);
768 	while (!skb_queue_empty(q)) {
769 		spin_unlock_irqrestore(&q->lock, flags);
770 		schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
771 		set_current_state(TASK_UNINTERRUPTIBLE);
772 		spin_lock_irqsave(&q->lock, flags);
773 	}
774 	spin_unlock_irqrestore(&q->lock, flags);
775 }
776 
777 // precondition: never called in_interrupt
778 static void usbnet_terminate_urbs(struct usbnet *dev)
779 {
780 	DECLARE_WAITQUEUE(wait, current);
781 	int temp;
782 
783 	/* ensure there are no more active urbs */
784 	add_wait_queue(&dev->wait, &wait);
785 	set_current_state(TASK_UNINTERRUPTIBLE);
786 	temp = unlink_urbs(dev, &dev->txq) +
787 		unlink_urbs(dev, &dev->rxq);
788 
789 	/* maybe wait for deletions to finish. */
790 	wait_skb_queue_empty(&dev->rxq);
791 	wait_skb_queue_empty(&dev->txq);
792 	wait_skb_queue_empty(&dev->done);
793 	netif_dbg(dev, ifdown, dev->net,
794 		  "waited for %d urb completions\n", temp);
795 	set_current_state(TASK_RUNNING);
796 	remove_wait_queue(&dev->wait, &wait);
797 }
798 
799 int usbnet_stop (struct net_device *net)
800 {
801 	struct usbnet		*dev = netdev_priv(net);
802 	const struct driver_info *info = dev->driver_info;
803 	int			retval, pm, mpn;
804 
805 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
806 	netif_stop_queue (net);
807 
808 	netif_info(dev, ifdown, dev->net,
809 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
810 		   net->stats.rx_packets, net->stats.tx_packets,
811 		   net->stats.rx_errors, net->stats.tx_errors);
812 
813 	/* to not race resume */
814 	pm = usb_autopm_get_interface(dev->intf);
815 	/* allow minidriver to stop correctly (wireless devices to turn off
816 	 * radio etc) */
817 	if (info->stop) {
818 		retval = info->stop(dev);
819 		if (retval < 0)
820 			netif_info(dev, ifdown, dev->net,
821 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
822 				   retval,
823 				   dev->udev->bus->bus_name, dev->udev->devpath,
824 				   info->description);
825 	}
826 
827 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
828 		usbnet_terminate_urbs(dev);
829 
830 	usbnet_status_stop(dev);
831 
832 	usbnet_purge_paused_rxq(dev);
833 
834 	mpn = !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
835 
836 	/* deferred work (task, timer, softirq) must also stop.
837 	 * can't flush_scheduled_work() until we drop rtnl (later),
838 	 * else workers could deadlock; so make workers a NOP.
839 	 */
840 	dev->flags = 0;
841 	del_timer_sync (&dev->delay);
842 	tasklet_kill (&dev->bh);
843 	if (!pm)
844 		usb_autopm_put_interface(dev->intf);
845 
846 	if (info->manage_power && mpn)
847 		info->manage_power(dev, 0);
848 	else
849 		usb_autopm_put_interface(dev->intf);
850 
851 	return 0;
852 }
853 EXPORT_SYMBOL_GPL(usbnet_stop);
854 
855 /*-------------------------------------------------------------------------*/
856 
857 // posts reads, and enables write queuing
858 
859 // precondition: never called in_interrupt
860 
861 int usbnet_open (struct net_device *net)
862 {
863 	struct usbnet		*dev = netdev_priv(net);
864 	int			retval;
865 	const struct driver_info *info = dev->driver_info;
866 
867 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
868 		netif_info(dev, ifup, dev->net,
869 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
870 			   retval,
871 			   dev->udev->bus->bus_name,
872 			   dev->udev->devpath,
873 			   info->description);
874 		goto done_nopm;
875 	}
876 
877 	// put into "known safe" state
878 	if (info->reset && (retval = info->reset (dev)) < 0) {
879 		netif_info(dev, ifup, dev->net,
880 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
881 			   retval,
882 			   dev->udev->bus->bus_name,
883 			   dev->udev->devpath,
884 			   info->description);
885 		goto done;
886 	}
887 
888 	/* hard_mtu or rx_urb_size may change in reset() */
889 	usbnet_update_max_qlen(dev);
890 
891 	// insist peer be connected
892 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
893 		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
894 		goto done;
895 	}
896 
897 	/* start any status interrupt transfer */
898 	if (dev->interrupt) {
899 		retval = usbnet_status_start(dev, GFP_KERNEL);
900 		if (retval < 0) {
901 			netif_err(dev, ifup, dev->net,
902 				  "intr submit %d\n", retval);
903 			goto done;
904 		}
905 	}
906 
907 	set_bit(EVENT_DEV_OPEN, &dev->flags);
908 	netif_start_queue (net);
909 	netif_info(dev, ifup, dev->net,
910 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
911 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
912 		   dev->net->mtu,
913 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
914 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
915 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
916 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
917 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
918 		   "simple");
919 
920 	/* reset rx error state */
921 	dev->pkt_cnt = 0;
922 	dev->pkt_err = 0;
923 	clear_bit(EVENT_RX_KILL, &dev->flags);
924 
925 	// delay posting reads until we're fully open
926 	tasklet_schedule (&dev->bh);
927 	if (info->manage_power) {
928 		retval = info->manage_power(dev, 1);
929 		if (retval < 0) {
930 			retval = 0;
931 			set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
932 		} else {
933 			usb_autopm_put_interface(dev->intf);
934 		}
935 	}
936 	return retval;
937 done:
938 	usb_autopm_put_interface(dev->intf);
939 done_nopm:
940 	return retval;
941 }
942 EXPORT_SYMBOL_GPL(usbnet_open);
943 
944 /*-------------------------------------------------------------------------*/
945 
946 /* ethtool methods; minidrivers may need to add some more, but
947  * they'll probably want to use this base set.
948  */
949 
950 int usbnet_get_link_ksettings(struct net_device *net,
951 			      struct ethtool_link_ksettings *cmd)
952 {
953 	struct usbnet *dev = netdev_priv(net);
954 
955 	if (!dev->mii.mdio_read)
956 		return -EOPNOTSUPP;
957 
958 	mii_ethtool_get_link_ksettings(&dev->mii, cmd);
959 
960 	return 0;
961 }
962 EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings);
963 
964 int usbnet_set_link_ksettings(struct net_device *net,
965 			      const struct ethtool_link_ksettings *cmd)
966 {
967 	struct usbnet *dev = netdev_priv(net);
968 	int retval;
969 
970 	if (!dev->mii.mdio_write)
971 		return -EOPNOTSUPP;
972 
973 	retval = mii_ethtool_set_link_ksettings(&dev->mii, cmd);
974 
975 	/* link speed/duplex might have changed */
976 	if (dev->driver_info->link_reset)
977 		dev->driver_info->link_reset(dev);
978 
979 	/* hard_mtu or rx_urb_size may change in link_reset() */
980 	usbnet_update_max_qlen(dev);
981 
982 	return retval;
983 }
984 EXPORT_SYMBOL_GPL(usbnet_set_link_ksettings);
985 
986 void usbnet_get_stats64(struct net_device *net, struct rtnl_link_stats64 *stats)
987 {
988 	struct usbnet *dev = netdev_priv(net);
989 	unsigned int start;
990 	int cpu;
991 
992 	netdev_stats_to_stats64(stats, &net->stats);
993 
994 	for_each_possible_cpu(cpu) {
995 		struct pcpu_sw_netstats *stats64;
996 		u64 rx_packets, rx_bytes;
997 		u64 tx_packets, tx_bytes;
998 
999 		stats64 = per_cpu_ptr(dev->stats64, cpu);
1000 
1001 		do {
1002 			start = u64_stats_fetch_begin_irq(&stats64->syncp);
1003 			rx_packets = stats64->rx_packets;
1004 			rx_bytes = stats64->rx_bytes;
1005 			tx_packets = stats64->tx_packets;
1006 			tx_bytes = stats64->tx_bytes;
1007 		} while (u64_stats_fetch_retry_irq(&stats64->syncp, start));
1008 
1009 		stats->rx_packets += rx_packets;
1010 		stats->rx_bytes += rx_bytes;
1011 		stats->tx_packets += tx_packets;
1012 		stats->tx_bytes += tx_bytes;
1013 	}
1014 }
1015 EXPORT_SYMBOL_GPL(usbnet_get_stats64);
1016 
1017 u32 usbnet_get_link (struct net_device *net)
1018 {
1019 	struct usbnet *dev = netdev_priv(net);
1020 
1021 	/* If a check_connect is defined, return its result */
1022 	if (dev->driver_info->check_connect)
1023 		return dev->driver_info->check_connect (dev) == 0;
1024 
1025 	/* if the device has mii operations, use those */
1026 	if (dev->mii.mdio_read)
1027 		return mii_link_ok(&dev->mii);
1028 
1029 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
1030 	return ethtool_op_get_link(net);
1031 }
1032 EXPORT_SYMBOL_GPL(usbnet_get_link);
1033 
1034 int usbnet_nway_reset(struct net_device *net)
1035 {
1036 	struct usbnet *dev = netdev_priv(net);
1037 
1038 	if (!dev->mii.mdio_write)
1039 		return -EOPNOTSUPP;
1040 
1041 	return mii_nway_restart(&dev->mii);
1042 }
1043 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
1044 
1045 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
1046 {
1047 	struct usbnet *dev = netdev_priv(net);
1048 
1049 	strlcpy (info->driver, dev->driver_name, sizeof info->driver);
1050 	strlcpy (info->version, DRIVER_VERSION, sizeof info->version);
1051 	strlcpy (info->fw_version, dev->driver_info->description,
1052 		sizeof info->fw_version);
1053 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
1054 }
1055 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
1056 
1057 u32 usbnet_get_msglevel (struct net_device *net)
1058 {
1059 	struct usbnet *dev = netdev_priv(net);
1060 
1061 	return dev->msg_enable;
1062 }
1063 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
1064 
1065 void usbnet_set_msglevel (struct net_device *net, u32 level)
1066 {
1067 	struct usbnet *dev = netdev_priv(net);
1068 
1069 	dev->msg_enable = level;
1070 }
1071 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
1072 
1073 /* drivers may override default ethtool_ops in their bind() routine */
1074 static const struct ethtool_ops usbnet_ethtool_ops = {
1075 	.get_link		= usbnet_get_link,
1076 	.nway_reset		= usbnet_nway_reset,
1077 	.get_drvinfo		= usbnet_get_drvinfo,
1078 	.get_msglevel		= usbnet_get_msglevel,
1079 	.set_msglevel		= usbnet_set_msglevel,
1080 	.get_ts_info		= ethtool_op_get_ts_info,
1081 	.get_link_ksettings	= usbnet_get_link_ksettings,
1082 	.set_link_ksettings	= usbnet_set_link_ksettings,
1083 };
1084 
1085 /*-------------------------------------------------------------------------*/
1086 
1087 static void __handle_link_change(struct usbnet *dev)
1088 {
1089 	if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
1090 		return;
1091 
1092 	if (!netif_carrier_ok(dev->net)) {
1093 		/* kill URBs for reading packets to save bus bandwidth */
1094 		unlink_urbs(dev, &dev->rxq);
1095 
1096 		/*
1097 		 * tx_timeout will unlink URBs for sending packets and
1098 		 * tx queue is stopped by netcore after link becomes off
1099 		 */
1100 	} else {
1101 		/* submitting URBs for reading packets */
1102 		tasklet_schedule(&dev->bh);
1103 	}
1104 
1105 	/* hard_mtu or rx_urb_size may change during link change */
1106 	usbnet_update_max_qlen(dev);
1107 
1108 	clear_bit(EVENT_LINK_CHANGE, &dev->flags);
1109 }
1110 
1111 static void usbnet_set_rx_mode(struct net_device *net)
1112 {
1113 	struct usbnet		*dev = netdev_priv(net);
1114 
1115 	usbnet_defer_kevent(dev, EVENT_SET_RX_MODE);
1116 }
1117 
1118 static void __handle_set_rx_mode(struct usbnet *dev)
1119 {
1120 	if (dev->driver_info->set_rx_mode)
1121 		(dev->driver_info->set_rx_mode)(dev);
1122 
1123 	clear_bit(EVENT_SET_RX_MODE, &dev->flags);
1124 }
1125 
1126 /* work that cannot be done in interrupt context uses keventd.
1127  *
1128  * NOTE:  with 2.5 we could do more of this using completion callbacks,
1129  * especially now that control transfers can be queued.
1130  */
1131 static void
1132 usbnet_deferred_kevent (struct work_struct *work)
1133 {
1134 	struct usbnet		*dev =
1135 		container_of(work, struct usbnet, kevent);
1136 	int			status;
1137 
1138 	/* usb_clear_halt() needs a thread context */
1139 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
1140 		unlink_urbs (dev, &dev->txq);
1141 		status = usb_autopm_get_interface(dev->intf);
1142 		if (status < 0)
1143 			goto fail_pipe;
1144 		status = usb_clear_halt (dev->udev, dev->out);
1145 		usb_autopm_put_interface(dev->intf);
1146 		if (status < 0 &&
1147 		    status != -EPIPE &&
1148 		    status != -ESHUTDOWN) {
1149 			if (netif_msg_tx_err (dev))
1150 fail_pipe:
1151 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
1152 					   status);
1153 		} else {
1154 			clear_bit (EVENT_TX_HALT, &dev->flags);
1155 			if (status != -ESHUTDOWN)
1156 				netif_wake_queue (dev->net);
1157 		}
1158 	}
1159 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
1160 		unlink_urbs (dev, &dev->rxq);
1161 		status = usb_autopm_get_interface(dev->intf);
1162 		if (status < 0)
1163 			goto fail_halt;
1164 		status = usb_clear_halt (dev->udev, dev->in);
1165 		usb_autopm_put_interface(dev->intf);
1166 		if (status < 0 &&
1167 		    status != -EPIPE &&
1168 		    status != -ESHUTDOWN) {
1169 			if (netif_msg_rx_err (dev))
1170 fail_halt:
1171 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
1172 					   status);
1173 		} else {
1174 			clear_bit (EVENT_RX_HALT, &dev->flags);
1175 			tasklet_schedule (&dev->bh);
1176 		}
1177 	}
1178 
1179 	/* tasklet could resubmit itself forever if memory is tight */
1180 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
1181 		struct urb	*urb = NULL;
1182 		int resched = 1;
1183 
1184 		if (netif_running (dev->net))
1185 			urb = usb_alloc_urb (0, GFP_KERNEL);
1186 		else
1187 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1188 		if (urb != NULL) {
1189 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1190 			status = usb_autopm_get_interface(dev->intf);
1191 			if (status < 0) {
1192 				usb_free_urb(urb);
1193 				goto fail_lowmem;
1194 			}
1195 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
1196 				resched = 0;
1197 			usb_autopm_put_interface(dev->intf);
1198 fail_lowmem:
1199 			if (resched)
1200 				tasklet_schedule (&dev->bh);
1201 		}
1202 	}
1203 
1204 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
1205 		const struct driver_info *info = dev->driver_info;
1206 		int			retval = 0;
1207 
1208 		clear_bit (EVENT_LINK_RESET, &dev->flags);
1209 		status = usb_autopm_get_interface(dev->intf);
1210 		if (status < 0)
1211 			goto skip_reset;
1212 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1213 			usb_autopm_put_interface(dev->intf);
1214 skip_reset:
1215 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1216 				    retval,
1217 				    dev->udev->bus->bus_name,
1218 				    dev->udev->devpath,
1219 				    info->description);
1220 		} else {
1221 			usb_autopm_put_interface(dev->intf);
1222 		}
1223 
1224 		/* handle link change from link resetting */
1225 		__handle_link_change(dev);
1226 	}
1227 
1228 	if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
1229 		__handle_link_change(dev);
1230 
1231 	if (test_bit (EVENT_SET_RX_MODE, &dev->flags))
1232 		__handle_set_rx_mode(dev);
1233 
1234 
1235 	if (dev->flags)
1236 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1237 }
1238 
1239 /*-------------------------------------------------------------------------*/
1240 
1241 static void tx_complete (struct urb *urb)
1242 {
1243 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1244 	struct skb_data		*entry = (struct skb_data *) skb->cb;
1245 	struct usbnet		*dev = entry->dev;
1246 
1247 	if (urb->status == 0) {
1248 		struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->stats64);
1249 		unsigned long flags;
1250 
1251 		flags = u64_stats_update_begin_irqsave(&stats64->syncp);
1252 		stats64->tx_packets += entry->packets;
1253 		stats64->tx_bytes += entry->length;
1254 		u64_stats_update_end_irqrestore(&stats64->syncp, flags);
1255 	} else {
1256 		dev->net->stats.tx_errors++;
1257 
1258 		switch (urb->status) {
1259 		case -EPIPE:
1260 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1261 			break;
1262 
1263 		/* software-driven interface shutdown */
1264 		case -ECONNRESET:		// async unlink
1265 		case -ESHUTDOWN:		// hardware gone
1266 			break;
1267 
1268 		/* like rx, tx gets controller i/o faults during hub_wq
1269 		 * delays and so it uses the same throttling mechanism.
1270 		 */
1271 		case -EPROTO:
1272 		case -ETIME:
1273 		case -EILSEQ:
1274 			usb_mark_last_busy(dev->udev);
1275 			if (!timer_pending (&dev->delay)) {
1276 				mod_timer (&dev->delay,
1277 					jiffies + THROTTLE_JIFFIES);
1278 				netif_dbg(dev, link, dev->net,
1279 					  "tx throttle %d\n", urb->status);
1280 			}
1281 			netif_stop_queue (dev->net);
1282 			break;
1283 		default:
1284 			netif_dbg(dev, tx_err, dev->net,
1285 				  "tx err %d\n", entry->urb->status);
1286 			break;
1287 		}
1288 	}
1289 
1290 	usb_autopm_put_interface_async(dev->intf);
1291 	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1292 }
1293 
1294 /*-------------------------------------------------------------------------*/
1295 
1296 void usbnet_tx_timeout (struct net_device *net)
1297 {
1298 	struct usbnet		*dev = netdev_priv(net);
1299 
1300 	unlink_urbs (dev, &dev->txq);
1301 	tasklet_schedule (&dev->bh);
1302 	/* this needs to be handled individually because the generic layer
1303 	 * doesn't know what is sufficient and could not restore private
1304 	 * information if a remedy of an unconditional reset were used.
1305 	 */
1306 	if (dev->driver_info->recover)
1307 		(dev->driver_info->recover)(dev);
1308 }
1309 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1310 
1311 /*-------------------------------------------------------------------------*/
1312 
1313 static int build_dma_sg(const struct sk_buff *skb, struct urb *urb)
1314 {
1315 	unsigned num_sgs, total_len = 0;
1316 	int i, s = 0;
1317 
1318 	num_sgs = skb_shinfo(skb)->nr_frags + 1;
1319 	if (num_sgs == 1)
1320 		return 0;
1321 
1322 	/* reserve one for zero packet */
1323 	urb->sg = kmalloc_array(num_sgs + 1, sizeof(struct scatterlist),
1324 				GFP_ATOMIC);
1325 	if (!urb->sg)
1326 		return -ENOMEM;
1327 
1328 	urb->num_sgs = num_sgs;
1329 	sg_init_table(urb->sg, urb->num_sgs + 1);
1330 
1331 	sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb));
1332 	total_len += skb_headlen(skb);
1333 
1334 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1335 		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
1336 
1337 		total_len += skb_frag_size(f);
1338 		sg_set_page(&urb->sg[i + s], skb_frag_page(f), skb_frag_size(f),
1339 			    skb_frag_off(f));
1340 	}
1341 	urb->transfer_buffer_length = total_len;
1342 
1343 	return 1;
1344 }
1345 
1346 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1347 				     struct net_device *net)
1348 {
1349 	struct usbnet		*dev = netdev_priv(net);
1350 	unsigned int			length;
1351 	struct urb		*urb = NULL;
1352 	struct skb_data		*entry;
1353 	const struct driver_info *info = dev->driver_info;
1354 	unsigned long		flags;
1355 	int retval;
1356 
1357 	if (skb)
1358 		skb_tx_timestamp(skb);
1359 
1360 	// some devices want funky USB-level framing, for
1361 	// win32 driver (usually) and/or hardware quirks
1362 	if (info->tx_fixup) {
1363 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1364 		if (!skb) {
1365 			/* packet collected; minidriver waiting for more */
1366 			if (info->flags & FLAG_MULTI_PACKET)
1367 				goto not_drop;
1368 			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1369 			goto drop;
1370 		}
1371 	}
1372 
1373 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1374 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1375 		goto drop;
1376 	}
1377 
1378 	entry = (struct skb_data *) skb->cb;
1379 	entry->urb = urb;
1380 	entry->dev = dev;
1381 
1382 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1383 			skb->data, skb->len, tx_complete, skb);
1384 	if (dev->can_dma_sg) {
1385 		if (build_dma_sg(skb, urb) < 0)
1386 			goto drop;
1387 	}
1388 	length = urb->transfer_buffer_length;
1389 
1390 	/* don't assume the hardware handles USB_ZERO_PACKET
1391 	 * NOTE:  strictly conforming cdc-ether devices should expect
1392 	 * the ZLP here, but ignore the one-byte packet.
1393 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1394 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1395 	 * packet itself if needed.
1396 	 */
1397 	if (length % dev->maxpacket == 0) {
1398 		if (!(info->flags & FLAG_SEND_ZLP)) {
1399 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1400 				length++;
1401 				if (skb_tailroom(skb) && !urb->num_sgs) {
1402 					skb->data[skb->len] = 0;
1403 					__skb_put(skb, 1);
1404 				} else if (urb->num_sgs)
1405 					sg_set_buf(&urb->sg[urb->num_sgs++],
1406 							dev->padding_pkt, 1);
1407 			}
1408 		} else
1409 			urb->transfer_flags |= URB_ZERO_PACKET;
1410 	}
1411 	urb->transfer_buffer_length = length;
1412 
1413 	if (info->flags & FLAG_MULTI_PACKET) {
1414 		/* Driver has set number of packets and a length delta.
1415 		 * Calculate the complete length and ensure that it's
1416 		 * positive.
1417 		 */
1418 		entry->length += length;
1419 		if (WARN_ON_ONCE(entry->length <= 0))
1420 			entry->length = length;
1421 	} else {
1422 		usbnet_set_skb_tx_stats(skb, 1, length);
1423 	}
1424 
1425 	spin_lock_irqsave(&dev->txq.lock, flags);
1426 	retval = usb_autopm_get_interface_async(dev->intf);
1427 	if (retval < 0) {
1428 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1429 		goto drop;
1430 	}
1431 	if (netif_queue_stopped(net)) {
1432 		usb_autopm_put_interface_async(dev->intf);
1433 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1434 		goto drop;
1435 	}
1436 
1437 #ifdef CONFIG_PM
1438 	/* if this triggers the device is still a sleep */
1439 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1440 		/* transmission will be done in resume */
1441 		usb_anchor_urb(urb, &dev->deferred);
1442 		/* no use to process more packets */
1443 		netif_stop_queue(net);
1444 		usb_put_urb(urb);
1445 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1446 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1447 		goto deferred;
1448 	}
1449 #endif
1450 
1451 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1452 	case -EPIPE:
1453 		netif_stop_queue (net);
1454 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1455 		usb_autopm_put_interface_async(dev->intf);
1456 		break;
1457 	default:
1458 		usb_autopm_put_interface_async(dev->intf);
1459 		netif_dbg(dev, tx_err, dev->net,
1460 			  "tx: submit urb err %d\n", retval);
1461 		break;
1462 	case 0:
1463 		netif_trans_update(net);
1464 		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1465 		if (dev->txq.qlen >= TX_QLEN (dev))
1466 			netif_stop_queue (net);
1467 	}
1468 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1469 
1470 	if (retval) {
1471 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1472 drop:
1473 		dev->net->stats.tx_dropped++;
1474 not_drop:
1475 		if (skb)
1476 			dev_kfree_skb_any (skb);
1477 		if (urb) {
1478 			kfree(urb->sg);
1479 			usb_free_urb(urb);
1480 		}
1481 	} else
1482 		netif_dbg(dev, tx_queued, dev->net,
1483 			  "> tx, len %u, type 0x%x\n", length, skb->protocol);
1484 #ifdef CONFIG_PM
1485 deferred:
1486 #endif
1487 	return NETDEV_TX_OK;
1488 }
1489 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1490 
1491 static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1492 {
1493 	struct urb	*urb;
1494 	int		i;
1495 	int		ret = 0;
1496 
1497 	/* don't refill the queue all at once */
1498 	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1499 		urb = usb_alloc_urb(0, flags);
1500 		if (urb != NULL) {
1501 			ret = rx_submit(dev, urb, flags);
1502 			if (ret)
1503 				goto err;
1504 		} else {
1505 			ret = -ENOMEM;
1506 			goto err;
1507 		}
1508 	}
1509 err:
1510 	return ret;
1511 }
1512 
1513 /*-------------------------------------------------------------------------*/
1514 
1515 // tasklet (work deferred from completions, in_irq) or timer
1516 
1517 static void usbnet_bh (struct timer_list *t)
1518 {
1519 	struct usbnet		*dev = from_timer(dev, t, delay);
1520 	struct sk_buff		*skb;
1521 	struct skb_data		*entry;
1522 
1523 	while ((skb = skb_dequeue (&dev->done))) {
1524 		entry = (struct skb_data *) skb->cb;
1525 		switch (entry->state) {
1526 		case rx_done:
1527 			entry->state = rx_cleanup;
1528 			rx_process (dev, skb);
1529 			continue;
1530 		case tx_done:
1531 			kfree(entry->urb->sg);
1532 			/* fall through */
1533 		case rx_cleanup:
1534 			usb_free_urb (entry->urb);
1535 			dev_kfree_skb (skb);
1536 			continue;
1537 		default:
1538 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1539 		}
1540 	}
1541 
1542 	/* restart RX again after disabling due to high error rate */
1543 	clear_bit(EVENT_RX_KILL, &dev->flags);
1544 
1545 	/* waiting for all pending urbs to complete?
1546 	 * only then can we forgo submitting anew
1547 	 */
1548 	if (waitqueue_active(&dev->wait)) {
1549 		if (dev->txq.qlen + dev->rxq.qlen + dev->done.qlen == 0)
1550 			wake_up_all(&dev->wait);
1551 
1552 	// or are we maybe short a few urbs?
1553 	} else if (netif_running (dev->net) &&
1554 		   netif_device_present (dev->net) &&
1555 		   netif_carrier_ok(dev->net) &&
1556 		   !timer_pending(&dev->delay) &&
1557 		   !test_bit(EVENT_RX_PAUSED, &dev->flags) &&
1558 		   !test_bit(EVENT_RX_HALT, &dev->flags)) {
1559 		int	temp = dev->rxq.qlen;
1560 
1561 		if (temp < RX_QLEN(dev)) {
1562 			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1563 				return;
1564 			if (temp != dev->rxq.qlen)
1565 				netif_dbg(dev, link, dev->net,
1566 					  "rxqlen %d --> %d\n",
1567 					  temp, dev->rxq.qlen);
1568 			if (dev->rxq.qlen < RX_QLEN(dev))
1569 				tasklet_schedule (&dev->bh);
1570 		}
1571 		if (dev->txq.qlen < TX_QLEN (dev))
1572 			netif_wake_queue (dev->net);
1573 	}
1574 }
1575 
1576 
1577 /*-------------------------------------------------------------------------
1578  *
1579  * USB Device Driver support
1580  *
1581  *-------------------------------------------------------------------------*/
1582 
1583 // precondition: never called in_interrupt
1584 
1585 void usbnet_disconnect (struct usb_interface *intf)
1586 {
1587 	struct usbnet		*dev;
1588 	struct usb_device	*xdev;
1589 	struct net_device	*net;
1590 
1591 	dev = usb_get_intfdata(intf);
1592 	usb_set_intfdata(intf, NULL);
1593 	if (!dev)
1594 		return;
1595 
1596 	xdev = interface_to_usbdev (intf);
1597 
1598 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1599 		   intf->dev.driver->name,
1600 		   xdev->bus->bus_name, xdev->devpath,
1601 		   dev->driver_info->description);
1602 
1603 	net = dev->net;
1604 	unregister_netdev (net);
1605 
1606 	cancel_work_sync(&dev->kevent);
1607 
1608 	usb_scuttle_anchored_urbs(&dev->deferred);
1609 
1610 	if (dev->driver_info->unbind)
1611 		dev->driver_info->unbind (dev, intf);
1612 
1613 	usb_kill_urb(dev->interrupt);
1614 	usb_free_urb(dev->interrupt);
1615 	kfree(dev->padding_pkt);
1616 
1617 	free_percpu(dev->stats64);
1618 	free_netdev(net);
1619 }
1620 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1621 
1622 static const struct net_device_ops usbnet_netdev_ops = {
1623 	.ndo_open		= usbnet_open,
1624 	.ndo_stop		= usbnet_stop,
1625 	.ndo_start_xmit		= usbnet_start_xmit,
1626 	.ndo_tx_timeout		= usbnet_tx_timeout,
1627 	.ndo_set_rx_mode	= usbnet_set_rx_mode,
1628 	.ndo_change_mtu		= usbnet_change_mtu,
1629 	.ndo_get_stats64	= usbnet_get_stats64,
1630 	.ndo_set_mac_address 	= eth_mac_addr,
1631 	.ndo_validate_addr	= eth_validate_addr,
1632 };
1633 
1634 /*-------------------------------------------------------------------------*/
1635 
1636 // precondition: never called in_interrupt
1637 
1638 static struct device_type wlan_type = {
1639 	.name	= "wlan",
1640 };
1641 
1642 static struct device_type wwan_type = {
1643 	.name	= "wwan",
1644 };
1645 
1646 int
1647 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1648 {
1649 	struct usbnet			*dev;
1650 	struct net_device		*net;
1651 	struct usb_host_interface	*interface;
1652 	const struct driver_info	*info;
1653 	struct usb_device		*xdev;
1654 	int				status;
1655 	const char			*name;
1656 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1657 
1658 	/* usbnet already took usb runtime pm, so have to enable the feature
1659 	 * for usb interface, otherwise usb_autopm_get_interface may return
1660 	 * failure if RUNTIME_PM is enabled.
1661 	 */
1662 	if (!driver->supports_autosuspend) {
1663 		driver->supports_autosuspend = 1;
1664 		pm_runtime_enable(&udev->dev);
1665 	}
1666 
1667 	name = udev->dev.driver->name;
1668 	info = (const struct driver_info *) prod->driver_info;
1669 	if (!info) {
1670 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1671 		return -ENODEV;
1672 	}
1673 	xdev = interface_to_usbdev (udev);
1674 	interface = udev->cur_altsetting;
1675 
1676 	status = -ENOMEM;
1677 
1678 	// set up our own records
1679 	net = alloc_etherdev(sizeof(*dev));
1680 	if (!net)
1681 		goto out;
1682 
1683 	/* netdev_printk() needs this so do it as early as possible */
1684 	SET_NETDEV_DEV(net, &udev->dev);
1685 
1686 	dev = netdev_priv(net);
1687 	dev->udev = xdev;
1688 	dev->intf = udev;
1689 	dev->driver_info = info;
1690 	dev->driver_name = name;
1691 
1692 	dev->stats64 = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1693 	if (!dev->stats64)
1694 		goto out0;
1695 
1696 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1697 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1698 	init_waitqueue_head(&dev->wait);
1699 	skb_queue_head_init (&dev->rxq);
1700 	skb_queue_head_init (&dev->txq);
1701 	skb_queue_head_init (&dev->done);
1702 	skb_queue_head_init(&dev->rxq_pause);
1703 	dev->bh.func = (void (*)(unsigned long))usbnet_bh;
1704 	dev->bh.data = (unsigned long)&dev->delay;
1705 	INIT_WORK (&dev->kevent, usbnet_deferred_kevent);
1706 	init_usb_anchor(&dev->deferred);
1707 	timer_setup(&dev->delay, usbnet_bh, 0);
1708 	mutex_init (&dev->phy_mutex);
1709 	mutex_init(&dev->interrupt_mutex);
1710 	dev->interrupt_count = 0;
1711 
1712 	dev->net = net;
1713 	strcpy (net->name, "usb%d");
1714 	memcpy (net->dev_addr, node_id, sizeof node_id);
1715 
1716 	/* rx and tx sides can use different message sizes;
1717 	 * bind() should set rx_urb_size in that case.
1718 	 */
1719 	dev->hard_mtu = net->mtu + net->hard_header_len;
1720 	net->min_mtu = 0;
1721 	net->max_mtu = ETH_MAX_MTU;
1722 
1723 	net->netdev_ops = &usbnet_netdev_ops;
1724 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1725 	net->ethtool_ops = &usbnet_ethtool_ops;
1726 
1727 	// allow device-specific bind/init procedures
1728 	// NOTE net->name still not usable ...
1729 	if (info->bind) {
1730 		status = info->bind (dev, udev);
1731 		if (status < 0)
1732 			goto out1;
1733 
1734 		// heuristic:  "usb%d" for links we know are two-host,
1735 		// else "eth%d" when there's reasonable doubt.  userspace
1736 		// can rename the link if it knows better.
1737 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1738 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1739 		     (net->dev_addr [0] & 0x02) == 0))
1740 			strcpy (net->name, "eth%d");
1741 		/* WLAN devices should always be named "wlan%d" */
1742 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1743 			strcpy(net->name, "wlan%d");
1744 		/* WWAN devices should always be named "wwan%d" */
1745 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1746 			strcpy(net->name, "wwan%d");
1747 
1748 		/* devices that cannot do ARP */
1749 		if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1750 			net->flags |= IFF_NOARP;
1751 
1752 		/* maybe the remote can't receive an Ethernet MTU */
1753 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1754 			net->mtu = dev->hard_mtu - net->hard_header_len;
1755 	} else if (!info->in || !info->out)
1756 		status = usbnet_get_endpoints (dev, udev);
1757 	else {
1758 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1759 		dev->out = usb_sndbulkpipe (xdev, info->out);
1760 		if (!(info->flags & FLAG_NO_SETINT))
1761 			status = usb_set_interface (xdev,
1762 				interface->desc.bInterfaceNumber,
1763 				interface->desc.bAlternateSetting);
1764 		else
1765 			status = 0;
1766 
1767 	}
1768 	if (status >= 0 && dev->status)
1769 		status = init_status (dev, udev);
1770 	if (status < 0)
1771 		goto out3;
1772 
1773 	if (!dev->rx_urb_size)
1774 		dev->rx_urb_size = dev->hard_mtu;
1775 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1776 
1777 	/* let userspace know we have a random address */
1778 	if (ether_addr_equal(net->dev_addr, node_id))
1779 		net->addr_assign_type = NET_ADDR_RANDOM;
1780 
1781 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1782 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1783 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1784 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1785 
1786 	/* initialize max rx_qlen and tx_qlen */
1787 	usbnet_update_max_qlen(dev);
1788 
1789 	if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&
1790 		!(info->flags & FLAG_MULTI_PACKET)) {
1791 		dev->padding_pkt = kzalloc(1, GFP_KERNEL);
1792 		if (!dev->padding_pkt) {
1793 			status = -ENOMEM;
1794 			goto out4;
1795 		}
1796 	}
1797 
1798 	status = register_netdev (net);
1799 	if (status)
1800 		goto out5;
1801 	netif_info(dev, probe, dev->net,
1802 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1803 		   udev->dev.driver->name,
1804 		   xdev->bus->bus_name, xdev->devpath,
1805 		   dev->driver_info->description,
1806 		   net->dev_addr);
1807 
1808 	// ok, it's ready to go.
1809 	usb_set_intfdata (udev, dev);
1810 
1811 	netif_device_attach (net);
1812 
1813 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1814 		usbnet_link_change(dev, 0, 0);
1815 
1816 	return 0;
1817 
1818 out5:
1819 	kfree(dev->padding_pkt);
1820 out4:
1821 	usb_free_urb(dev->interrupt);
1822 out3:
1823 	if (info->unbind)
1824 		info->unbind (dev, udev);
1825 out1:
1826 	/* subdrivers must undo all they did in bind() if they
1827 	 * fail it, but we may fail later and a deferred kevent
1828 	 * may trigger an error resubmitting itself and, worse,
1829 	 * schedule a timer. So we kill it all just in case.
1830 	 */
1831 	cancel_work_sync(&dev->kevent);
1832 	del_timer_sync(&dev->delay);
1833 	free_percpu(dev->stats64);
1834 out0:
1835 	free_netdev(net);
1836 out:
1837 	return status;
1838 }
1839 EXPORT_SYMBOL_GPL(usbnet_probe);
1840 
1841 /*-------------------------------------------------------------------------*/
1842 
1843 /*
1844  * suspend the whole driver as soon as the first interface is suspended
1845  * resume only when the last interface is resumed
1846  */
1847 
1848 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1849 {
1850 	struct usbnet		*dev = usb_get_intfdata(intf);
1851 
1852 	if (!dev->suspend_count++) {
1853 		spin_lock_irq(&dev->txq.lock);
1854 		/* don't autosuspend while transmitting */
1855 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1856 			dev->suspend_count--;
1857 			spin_unlock_irq(&dev->txq.lock);
1858 			return -EBUSY;
1859 		} else {
1860 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1861 			spin_unlock_irq(&dev->txq.lock);
1862 		}
1863 		/*
1864 		 * accelerate emptying of the rx and queues, to avoid
1865 		 * having everything error out.
1866 		 */
1867 		netif_device_detach (dev->net);
1868 		usbnet_terminate_urbs(dev);
1869 		__usbnet_status_stop_force(dev);
1870 
1871 		/*
1872 		 * reattach so runtime management can use and
1873 		 * wake the device
1874 		 */
1875 		netif_device_attach (dev->net);
1876 	}
1877 	return 0;
1878 }
1879 EXPORT_SYMBOL_GPL(usbnet_suspend);
1880 
1881 int usbnet_resume (struct usb_interface *intf)
1882 {
1883 	struct usbnet		*dev = usb_get_intfdata(intf);
1884 	struct sk_buff          *skb;
1885 	struct urb              *res;
1886 	int                     retval;
1887 
1888 	if (!--dev->suspend_count) {
1889 		/* resume interrupt URB if it was previously submitted */
1890 		__usbnet_status_start_force(dev, GFP_NOIO);
1891 
1892 		spin_lock_irq(&dev->txq.lock);
1893 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1894 
1895 			skb = (struct sk_buff *)res->context;
1896 			retval = usb_submit_urb(res, GFP_ATOMIC);
1897 			if (retval < 0) {
1898 				dev_kfree_skb_any(skb);
1899 				kfree(res->sg);
1900 				usb_free_urb(res);
1901 				usb_autopm_put_interface_async(dev->intf);
1902 			} else {
1903 				netif_trans_update(dev->net);
1904 				__skb_queue_tail(&dev->txq, skb);
1905 			}
1906 		}
1907 
1908 		smp_mb();
1909 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1910 		spin_unlock_irq(&dev->txq.lock);
1911 
1912 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1913 			/* handle remote wakeup ASAP
1914 			 * we cannot race against stop
1915 			 */
1916 			if (netif_device_present(dev->net) &&
1917 				!timer_pending(&dev->delay) &&
1918 				!test_bit(EVENT_RX_HALT, &dev->flags))
1919 					rx_alloc_submit(dev, GFP_NOIO);
1920 
1921 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1922 				netif_tx_wake_all_queues(dev->net);
1923 			tasklet_schedule (&dev->bh);
1924 		}
1925 	}
1926 
1927 	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1928 		usb_autopm_get_interface_no_resume(intf);
1929 
1930 	return 0;
1931 }
1932 EXPORT_SYMBOL_GPL(usbnet_resume);
1933 
1934 /*
1935  * Either a subdriver implements manage_power, then it is assumed to always
1936  * be ready to be suspended or it reports the readiness to be suspended
1937  * explicitly
1938  */
1939 void usbnet_device_suggests_idle(struct usbnet *dev)
1940 {
1941 	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1942 		dev->intf->needs_remote_wakeup = 1;
1943 		usb_autopm_put_interface_async(dev->intf);
1944 	}
1945 }
1946 EXPORT_SYMBOL(usbnet_device_suggests_idle);
1947 
1948 /*
1949  * For devices that can do without special commands
1950  */
1951 int usbnet_manage_power(struct usbnet *dev, int on)
1952 {
1953 	dev->intf->needs_remote_wakeup = on;
1954 	return 0;
1955 }
1956 EXPORT_SYMBOL(usbnet_manage_power);
1957 
1958 void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
1959 {
1960 	/* update link after link is reseted */
1961 	if (link && !need_reset)
1962 		netif_carrier_on(dev->net);
1963 	else
1964 		netif_carrier_off(dev->net);
1965 
1966 	if (need_reset && link)
1967 		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
1968 	else
1969 		usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
1970 }
1971 EXPORT_SYMBOL(usbnet_link_change);
1972 
1973 /*-------------------------------------------------------------------------*/
1974 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1975 			     u16 value, u16 index, void *data, u16 size)
1976 {
1977 	void *buf = NULL;
1978 	int err = -ENOMEM;
1979 
1980 	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
1981 		   " value=0x%04x index=0x%04x size=%d\n",
1982 		   cmd, reqtype, value, index, size);
1983 
1984 	if (size) {
1985 		buf = kmalloc(size, GFP_KERNEL);
1986 		if (!buf)
1987 			goto out;
1988 	}
1989 
1990 	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
1991 			      cmd, reqtype, value, index, buf, size,
1992 			      USB_CTRL_GET_TIMEOUT);
1993 	if (err > 0 && err <= size) {
1994         if (data)
1995             memcpy(data, buf, err);
1996         else
1997             netdev_dbg(dev->net,
1998                 "Huh? Data requested but thrown away.\n");
1999     }
2000 	kfree(buf);
2001 out:
2002 	return err;
2003 }
2004 
2005 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2006 			      u16 value, u16 index, const void *data,
2007 			      u16 size)
2008 {
2009 	void *buf = NULL;
2010 	int err = -ENOMEM;
2011 
2012 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2013 		   " value=0x%04x index=0x%04x size=%d\n",
2014 		   cmd, reqtype, value, index, size);
2015 
2016 	if (data) {
2017 		buf = kmemdup(data, size, GFP_KERNEL);
2018 		if (!buf)
2019 			goto out;
2020 	} else {
2021         if (size) {
2022             WARN_ON_ONCE(1);
2023             err = -EINVAL;
2024             goto out;
2025         }
2026     }
2027 
2028 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
2029 			      cmd, reqtype, value, index, buf, size,
2030 			      USB_CTRL_SET_TIMEOUT);
2031 	kfree(buf);
2032 
2033 out:
2034 	return err;
2035 }
2036 
2037 /*
2038  * The function can't be called inside suspend/resume callback,
2039  * otherwise deadlock will be caused.
2040  */
2041 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2042 		    u16 value, u16 index, void *data, u16 size)
2043 {
2044 	int ret;
2045 
2046 	if (usb_autopm_get_interface(dev->intf) < 0)
2047 		return -ENODEV;
2048 	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2049 				data, size);
2050 	usb_autopm_put_interface(dev->intf);
2051 	return ret;
2052 }
2053 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
2054 
2055 /*
2056  * The function can't be called inside suspend/resume callback,
2057  * otherwise deadlock will be caused.
2058  */
2059 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2060 		     u16 value, u16 index, const void *data, u16 size)
2061 {
2062 	int ret;
2063 
2064 	if (usb_autopm_get_interface(dev->intf) < 0)
2065 		return -ENODEV;
2066 	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2067 				 data, size);
2068 	usb_autopm_put_interface(dev->intf);
2069 	return ret;
2070 }
2071 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
2072 
2073 /*
2074  * The function can be called inside suspend/resume callback safely
2075  * and should only be called by suspend/resume callback generally.
2076  */
2077 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2078 			  u16 value, u16 index, void *data, u16 size)
2079 {
2080 	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2081 				 data, size);
2082 }
2083 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
2084 
2085 /*
2086  * The function can be called inside suspend/resume callback safely
2087  * and should only be called by suspend/resume callback generally.
2088  */
2089 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2090 			  u16 value, u16 index, const void *data,
2091 			  u16 size)
2092 {
2093 	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2094 				  data, size);
2095 }
2096 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
2097 
2098 static void usbnet_async_cmd_cb(struct urb *urb)
2099 {
2100 	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
2101 	int status = urb->status;
2102 
2103 	if (status < 0)
2104 		dev_dbg(&urb->dev->dev, "%s failed with %d",
2105 			__func__, status);
2106 
2107 	kfree(req);
2108 	usb_free_urb(urb);
2109 }
2110 
2111 /*
2112  * The caller must make sure that device can't be put into suspend
2113  * state until the control URB completes.
2114  */
2115 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
2116 			   u16 value, u16 index, const void *data, u16 size)
2117 {
2118 	struct usb_ctrlrequest *req = NULL;
2119 	struct urb *urb;
2120 	int err = -ENOMEM;
2121 	void *buf = NULL;
2122 
2123 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2124 		   " value=0x%04x index=0x%04x size=%d\n",
2125 		   cmd, reqtype, value, index, size);
2126 
2127 	urb = usb_alloc_urb(0, GFP_ATOMIC);
2128 	if (!urb)
2129 		goto fail;
2130 
2131 	if (data) {
2132 		buf = kmemdup(data, size, GFP_ATOMIC);
2133 		if (!buf) {
2134 			netdev_err(dev->net, "Error allocating buffer"
2135 				   " in %s!\n", __func__);
2136 			goto fail_free;
2137 		}
2138 	}
2139 
2140 	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
2141 	if (!req)
2142 		goto fail_free_buf;
2143 
2144 	req->bRequestType = reqtype;
2145 	req->bRequest = cmd;
2146 	req->wValue = cpu_to_le16(value);
2147 	req->wIndex = cpu_to_le16(index);
2148 	req->wLength = cpu_to_le16(size);
2149 
2150 	usb_fill_control_urb(urb, dev->udev,
2151 			     usb_sndctrlpipe(dev->udev, 0),
2152 			     (void *)req, buf, size,
2153 			     usbnet_async_cmd_cb, req);
2154 	urb->transfer_flags |= URB_FREE_BUFFER;
2155 
2156 	err = usb_submit_urb(urb, GFP_ATOMIC);
2157 	if (err < 0) {
2158 		netdev_err(dev->net, "Error submitting the control"
2159 			   " message: status=%d\n", err);
2160 		goto fail_free;
2161 	}
2162 	return 0;
2163 
2164 fail_free_buf:
2165 	kfree(buf);
2166 fail_free:
2167 	kfree(req);
2168 	usb_free_urb(urb);
2169 fail:
2170 	return err;
2171 
2172 }
2173 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
2174 /*-------------------------------------------------------------------------*/
2175 
2176 static int __init usbnet_init(void)
2177 {
2178 	/* Compiler should optimize this out. */
2179 	BUILD_BUG_ON(
2180 		FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
2181 
2182 	eth_random_addr(node_id);
2183 	return 0;
2184 }
2185 module_init(usbnet_init);
2186 
2187 static void __exit usbnet_exit(void)
2188 {
2189 }
2190 module_exit(usbnet_exit);
2191 
2192 MODULE_AUTHOR("David Brownell");
2193 MODULE_DESCRIPTION("USB network driver framework");
2194 MODULE_LICENSE("GPL");
2195