xref: /openbmc/linux/drivers/net/usb/usbnet.c (revision 8730046c)
1 /*
2  * USB Network driver infrastructure
3  * Copyright (C) 2000-2005 by David Brownell
4  * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 /*
21  * This is a generic "USB networking" framework that works with several
22  * kinds of full and high speed networking devices:  host-to-host cables,
23  * smart usb peripherals, and actual Ethernet adapters.
24  *
25  * These devices usually differ in terms of control protocols (if they
26  * even have one!) and sometimes they define new framing to wrap or batch
27  * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
28  * so interface (un)binding, endpoint I/O queues, fault handling, and other
29  * issues can usefully be addressed by this framework.
30  */
31 
32 // #define	DEBUG			// error path messages, extra info
33 // #define	VERBOSE			// more; success messages
34 
35 #include <linux/module.h>
36 #include <linux/init.h>
37 #include <linux/netdevice.h>
38 #include <linux/etherdevice.h>
39 #include <linux/ctype.h>
40 #include <linux/ethtool.h>
41 #include <linux/workqueue.h>
42 #include <linux/mii.h>
43 #include <linux/usb.h>
44 #include <linux/usb/usbnet.h>
45 #include <linux/slab.h>
46 #include <linux/kernel.h>
47 #include <linux/pm_runtime.h>
48 
49 #define DRIVER_VERSION		"22-Aug-2005"
50 
51 
52 /*-------------------------------------------------------------------------*/
53 
54 /*
55  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
56  * Several dozen bytes of IPv4 data can fit in two such transactions.
57  * One maximum size Ethernet packet takes twenty four of them.
58  * For high speed, each frame comfortably fits almost 36 max size
59  * Ethernet packets (so queues should be bigger).
60  *
61  * The goal is to let the USB host controller be busy for 5msec or
62  * more before an irq is required, under load.  Jumbograms change
63  * the equation.
64  */
65 #define	MAX_QUEUE_MEMORY	(60 * 1518)
66 #define	RX_QLEN(dev)		((dev)->rx_qlen)
67 #define	TX_QLEN(dev)		((dev)->tx_qlen)
68 
69 // reawaken network queue this soon after stopping; else watchdog barks
70 #define TX_TIMEOUT_JIFFIES	(5*HZ)
71 
72 /* throttle rx/tx briefly after some faults, so hub_wq might disconnect()
73  * us (it polls at HZ/4 usually) before we report too many false errors.
74  */
75 #define THROTTLE_JIFFIES	(HZ/8)
76 
77 // between wakeups
78 #define UNLINK_TIMEOUT_MS	3
79 
80 /*-------------------------------------------------------------------------*/
81 
82 // randomly generated ethernet address
83 static u8	node_id [ETH_ALEN];
84 
85 static const char driver_name [] = "usbnet";
86 
87 /* use ethtool to change the level for any given device */
88 static int msg_level = -1;
89 module_param (msg_level, int, 0);
90 MODULE_PARM_DESC (msg_level, "Override default message level");
91 
92 /*-------------------------------------------------------------------------*/
93 
94 /* handles CDC Ethernet and many other network "bulk data" interfaces */
95 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
96 {
97 	int				tmp;
98 	struct usb_host_interface	*alt = NULL;
99 	struct usb_host_endpoint	*in = NULL, *out = NULL;
100 	struct usb_host_endpoint	*status = NULL;
101 
102 	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
103 		unsigned	ep;
104 
105 		in = out = status = NULL;
106 		alt = intf->altsetting + tmp;
107 
108 		/* take the first altsetting with in-bulk + out-bulk;
109 		 * remember any status endpoint, just in case;
110 		 * ignore other endpoints and altsettings.
111 		 */
112 		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
113 			struct usb_host_endpoint	*e;
114 			int				intr = 0;
115 
116 			e = alt->endpoint + ep;
117 			switch (e->desc.bmAttributes) {
118 			case USB_ENDPOINT_XFER_INT:
119 				if (!usb_endpoint_dir_in(&e->desc))
120 					continue;
121 				intr = 1;
122 				/* FALLTHROUGH */
123 			case USB_ENDPOINT_XFER_BULK:
124 				break;
125 			default:
126 				continue;
127 			}
128 			if (usb_endpoint_dir_in(&e->desc)) {
129 				if (!intr && !in)
130 					in = e;
131 				else if (intr && !status)
132 					status = e;
133 			} else {
134 				if (!out)
135 					out = e;
136 			}
137 		}
138 		if (in && out)
139 			break;
140 	}
141 	if (!alt || !in || !out)
142 		return -EINVAL;
143 
144 	if (alt->desc.bAlternateSetting != 0 ||
145 	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
146 		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
147 				alt->desc.bAlternateSetting);
148 		if (tmp < 0)
149 			return tmp;
150 	}
151 
152 	dev->in = usb_rcvbulkpipe (dev->udev,
153 			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
154 	dev->out = usb_sndbulkpipe (dev->udev,
155 			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
156 	dev->status = status;
157 	return 0;
158 }
159 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
160 
161 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
162 {
163 	int 		tmp = -1, ret;
164 	unsigned char	buf [13];
165 
166 	ret = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
167 	if (ret == 12)
168 		tmp = hex2bin(dev->net->dev_addr, buf, 6);
169 	if (tmp < 0) {
170 		dev_dbg(&dev->udev->dev,
171 			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
172 		if (ret >= 0)
173 			ret = -EINVAL;
174 		return ret;
175 	}
176 	return 0;
177 }
178 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
179 
180 static void intr_complete (struct urb *urb)
181 {
182 	struct usbnet	*dev = urb->context;
183 	int		status = urb->status;
184 
185 	switch (status) {
186 	/* success */
187 	case 0:
188 		dev->driver_info->status(dev, urb);
189 		break;
190 
191 	/* software-driven interface shutdown */
192 	case -ENOENT:		/* urb killed */
193 	case -ESHUTDOWN:	/* hardware gone */
194 		netif_dbg(dev, ifdown, dev->net,
195 			  "intr shutdown, code %d\n", status);
196 		return;
197 
198 	/* NOTE:  not throttling like RX/TX, since this endpoint
199 	 * already polls infrequently
200 	 */
201 	default:
202 		netdev_dbg(dev->net, "intr status %d\n", status);
203 		break;
204 	}
205 
206 	status = usb_submit_urb (urb, GFP_ATOMIC);
207 	if (status != 0)
208 		netif_err(dev, timer, dev->net,
209 			  "intr resubmit --> %d\n", status);
210 }
211 
212 static int init_status (struct usbnet *dev, struct usb_interface *intf)
213 {
214 	char		*buf = NULL;
215 	unsigned	pipe = 0;
216 	unsigned	maxp;
217 	unsigned	period;
218 
219 	if (!dev->driver_info->status)
220 		return 0;
221 
222 	pipe = usb_rcvintpipe (dev->udev,
223 			dev->status->desc.bEndpointAddress
224 				& USB_ENDPOINT_NUMBER_MASK);
225 	maxp = usb_maxpacket (dev->udev, pipe, 0);
226 
227 	/* avoid 1 msec chatter:  min 8 msec poll rate */
228 	period = max ((int) dev->status->desc.bInterval,
229 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
230 
231 	buf = kmalloc (maxp, GFP_KERNEL);
232 	if (buf) {
233 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
234 		if (!dev->interrupt) {
235 			kfree (buf);
236 			return -ENOMEM;
237 		} else {
238 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
239 				buf, maxp, intr_complete, dev, period);
240 			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
241 			dev_dbg(&intf->dev,
242 				"status ep%din, %d bytes period %d\n",
243 				usb_pipeendpoint(pipe), maxp, period);
244 		}
245 	}
246 	return 0;
247 }
248 
249 /* Submit the interrupt URB if not previously submitted, increasing refcount */
250 int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
251 {
252 	int ret = 0;
253 
254 	WARN_ON_ONCE(dev->interrupt == NULL);
255 	if (dev->interrupt) {
256 		mutex_lock(&dev->interrupt_mutex);
257 
258 		if (++dev->interrupt_count == 1)
259 			ret = usb_submit_urb(dev->interrupt, mem_flags);
260 
261 		dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
262 			dev->interrupt_count);
263 		mutex_unlock(&dev->interrupt_mutex);
264 	}
265 	return ret;
266 }
267 EXPORT_SYMBOL_GPL(usbnet_status_start);
268 
269 /* For resume; submit interrupt URB if previously submitted */
270 static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
271 {
272 	int ret = 0;
273 
274 	mutex_lock(&dev->interrupt_mutex);
275 	if (dev->interrupt_count) {
276 		ret = usb_submit_urb(dev->interrupt, mem_flags);
277 		dev_dbg(&dev->udev->dev,
278 			"submitted interrupt URB for resume\n");
279 	}
280 	mutex_unlock(&dev->interrupt_mutex);
281 	return ret;
282 }
283 
284 /* Kill the interrupt URB if all submitters want it killed */
285 void usbnet_status_stop(struct usbnet *dev)
286 {
287 	if (dev->interrupt) {
288 		mutex_lock(&dev->interrupt_mutex);
289 		WARN_ON(dev->interrupt_count == 0);
290 
291 		if (dev->interrupt_count && --dev->interrupt_count == 0)
292 			usb_kill_urb(dev->interrupt);
293 
294 		dev_dbg(&dev->udev->dev,
295 			"decremented interrupt URB count to %d\n",
296 			dev->interrupt_count);
297 		mutex_unlock(&dev->interrupt_mutex);
298 	}
299 }
300 EXPORT_SYMBOL_GPL(usbnet_status_stop);
301 
302 /* For suspend; always kill interrupt URB */
303 static void __usbnet_status_stop_force(struct usbnet *dev)
304 {
305 	if (dev->interrupt) {
306 		mutex_lock(&dev->interrupt_mutex);
307 		usb_kill_urb(dev->interrupt);
308 		dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
309 		mutex_unlock(&dev->interrupt_mutex);
310 	}
311 }
312 
313 /* Passes this packet up the stack, updating its accounting.
314  * Some link protocols batch packets, so their rx_fixup paths
315  * can return clones as well as just modify the original skb.
316  */
317 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
318 {
319 	int	status;
320 
321 	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
322 		skb_queue_tail(&dev->rxq_pause, skb);
323 		return;
324 	}
325 
326 	/* only update if unset to allow minidriver rx_fixup override */
327 	if (skb->protocol == 0)
328 		skb->protocol = eth_type_trans (skb, dev->net);
329 
330 	dev->net->stats.rx_packets++;
331 	dev->net->stats.rx_bytes += skb->len;
332 
333 	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
334 		  skb->len + sizeof (struct ethhdr), skb->protocol);
335 	memset (skb->cb, 0, sizeof (struct skb_data));
336 
337 	if (skb_defer_rx_timestamp(skb))
338 		return;
339 
340 	status = netif_rx (skb);
341 	if (status != NET_RX_SUCCESS)
342 		netif_dbg(dev, rx_err, dev->net,
343 			  "netif_rx status %d\n", status);
344 }
345 EXPORT_SYMBOL_GPL(usbnet_skb_return);
346 
347 /* must be called if hard_mtu or rx_urb_size changed */
348 void usbnet_update_max_qlen(struct usbnet *dev)
349 {
350 	enum usb_device_speed speed = dev->udev->speed;
351 
352 	switch (speed) {
353 	case USB_SPEED_HIGH:
354 		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
355 		dev->tx_qlen = MAX_QUEUE_MEMORY / dev->hard_mtu;
356 		break;
357 	case USB_SPEED_SUPER:
358 	case USB_SPEED_SUPER_PLUS:
359 		/*
360 		 * Not take default 5ms qlen for super speed HC to
361 		 * save memory, and iperf tests show 2.5ms qlen can
362 		 * work well
363 		 */
364 		dev->rx_qlen = 5 * MAX_QUEUE_MEMORY / dev->rx_urb_size;
365 		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
366 		break;
367 	default:
368 		dev->rx_qlen = dev->tx_qlen = 4;
369 	}
370 }
371 EXPORT_SYMBOL_GPL(usbnet_update_max_qlen);
372 
373 
374 /*-------------------------------------------------------------------------
375  *
376  * Network Device Driver (peer link to "Host Device", from USB host)
377  *
378  *-------------------------------------------------------------------------*/
379 
380 int usbnet_change_mtu (struct net_device *net, int new_mtu)
381 {
382 	struct usbnet	*dev = netdev_priv(net);
383 	int		ll_mtu = new_mtu + net->hard_header_len;
384 	int		old_hard_mtu = dev->hard_mtu;
385 	int		old_rx_urb_size = dev->rx_urb_size;
386 
387 	// no second zero-length packet read wanted after mtu-sized packets
388 	if ((ll_mtu % dev->maxpacket) == 0)
389 		return -EDOM;
390 	net->mtu = new_mtu;
391 
392 	dev->hard_mtu = net->mtu + net->hard_header_len;
393 	if (dev->rx_urb_size == old_hard_mtu) {
394 		dev->rx_urb_size = dev->hard_mtu;
395 		if (dev->rx_urb_size > old_rx_urb_size) {
396 			usbnet_pause_rx(dev);
397 			usbnet_unlink_rx_urbs(dev);
398 			usbnet_resume_rx(dev);
399 		}
400 	}
401 
402 	/* max qlen depend on hard_mtu and rx_urb_size */
403 	usbnet_update_max_qlen(dev);
404 
405 	return 0;
406 }
407 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
408 
409 /* The caller must hold list->lock */
410 static void __usbnet_queue_skb(struct sk_buff_head *list,
411 			struct sk_buff *newsk, enum skb_state state)
412 {
413 	struct skb_data *entry = (struct skb_data *) newsk->cb;
414 
415 	__skb_queue_tail(list, newsk);
416 	entry->state = state;
417 }
418 
419 /*-------------------------------------------------------------------------*/
420 
421 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
422  * completion callbacks.  2.5 should have fixed those bugs...
423  */
424 
425 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
426 		struct sk_buff_head *list, enum skb_state state)
427 {
428 	unsigned long		flags;
429 	enum skb_state 		old_state;
430 	struct skb_data *entry = (struct skb_data *) skb->cb;
431 
432 	spin_lock_irqsave(&list->lock, flags);
433 	old_state = entry->state;
434 	entry->state = state;
435 	__skb_unlink(skb, list);
436 
437 	/* defer_bh() is never called with list == &dev->done.
438 	 * spin_lock_nested() tells lockdep that it is OK to take
439 	 * dev->done.lock here with list->lock held.
440 	 */
441 	spin_lock_nested(&dev->done.lock, SINGLE_DEPTH_NESTING);
442 
443 	__skb_queue_tail(&dev->done, skb);
444 	if (dev->done.qlen == 1)
445 		tasklet_schedule(&dev->bh);
446 	spin_unlock(&dev->done.lock);
447 	spin_unlock_irqrestore(&list->lock, flags);
448 	return old_state;
449 }
450 
451 /* some work can't be done in tasklets, so we use keventd
452  *
453  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
454  * but tasklet_schedule() doesn't.  hope the failure is rare.
455  */
456 void usbnet_defer_kevent (struct usbnet *dev, int work)
457 {
458 	set_bit (work, &dev->flags);
459 	if (!schedule_work (&dev->kevent)) {
460 		if (net_ratelimit())
461 			netdev_err(dev->net, "kevent %d may have been dropped\n", work);
462 	} else {
463 		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
464 	}
465 }
466 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
467 
468 /*-------------------------------------------------------------------------*/
469 
470 static void rx_complete (struct urb *urb);
471 
472 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
473 {
474 	struct sk_buff		*skb;
475 	struct skb_data		*entry;
476 	int			retval = 0;
477 	unsigned long		lockflags;
478 	size_t			size = dev->rx_urb_size;
479 
480 	/* prevent rx skb allocation when error ratio is high */
481 	if (test_bit(EVENT_RX_KILL, &dev->flags)) {
482 		usb_free_urb(urb);
483 		return -ENOLINK;
484 	}
485 
486 	skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
487 	if (!skb) {
488 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
489 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
490 		usb_free_urb (urb);
491 		return -ENOMEM;
492 	}
493 
494 	entry = (struct skb_data *) skb->cb;
495 	entry->urb = urb;
496 	entry->dev = dev;
497 	entry->length = 0;
498 
499 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
500 		skb->data, size, rx_complete, skb);
501 
502 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
503 
504 	if (netif_running (dev->net) &&
505 	    netif_device_present (dev->net) &&
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 	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 	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_settings (struct net_device *net, struct ethtool_cmd *cmd)
951 {
952 	struct usbnet *dev = netdev_priv(net);
953 
954 	if (!dev->mii.mdio_read)
955 		return -EOPNOTSUPP;
956 
957 	return mii_ethtool_gset(&dev->mii, cmd);
958 }
959 EXPORT_SYMBOL_GPL(usbnet_get_settings);
960 
961 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
962 {
963 	struct usbnet *dev = netdev_priv(net);
964 	int retval;
965 
966 	if (!dev->mii.mdio_write)
967 		return -EOPNOTSUPP;
968 
969 	retval = mii_ethtool_sset(&dev->mii, cmd);
970 
971 	/* link speed/duplex might have changed */
972 	if (dev->driver_info->link_reset)
973 		dev->driver_info->link_reset(dev);
974 
975 	/* hard_mtu or rx_urb_size may change in link_reset() */
976 	usbnet_update_max_qlen(dev);
977 
978 	return retval;
979 
980 }
981 EXPORT_SYMBOL_GPL(usbnet_set_settings);
982 
983 u32 usbnet_get_link (struct net_device *net)
984 {
985 	struct usbnet *dev = netdev_priv(net);
986 
987 	/* If a check_connect is defined, return its result */
988 	if (dev->driver_info->check_connect)
989 		return dev->driver_info->check_connect (dev) == 0;
990 
991 	/* if the device has mii operations, use those */
992 	if (dev->mii.mdio_read)
993 		return mii_link_ok(&dev->mii);
994 
995 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
996 	return ethtool_op_get_link(net);
997 }
998 EXPORT_SYMBOL_GPL(usbnet_get_link);
999 
1000 int usbnet_nway_reset(struct net_device *net)
1001 {
1002 	struct usbnet *dev = netdev_priv(net);
1003 
1004 	if (!dev->mii.mdio_write)
1005 		return -EOPNOTSUPP;
1006 
1007 	return mii_nway_restart(&dev->mii);
1008 }
1009 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
1010 
1011 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
1012 {
1013 	struct usbnet *dev = netdev_priv(net);
1014 
1015 	strlcpy (info->driver, dev->driver_name, sizeof info->driver);
1016 	strlcpy (info->version, DRIVER_VERSION, sizeof info->version);
1017 	strlcpy (info->fw_version, dev->driver_info->description,
1018 		sizeof info->fw_version);
1019 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
1020 }
1021 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
1022 
1023 u32 usbnet_get_msglevel (struct net_device *net)
1024 {
1025 	struct usbnet *dev = netdev_priv(net);
1026 
1027 	return dev->msg_enable;
1028 }
1029 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
1030 
1031 void usbnet_set_msglevel (struct net_device *net, u32 level)
1032 {
1033 	struct usbnet *dev = netdev_priv(net);
1034 
1035 	dev->msg_enable = level;
1036 }
1037 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
1038 
1039 /* drivers may override default ethtool_ops in their bind() routine */
1040 static const struct ethtool_ops usbnet_ethtool_ops = {
1041 	.get_settings		= usbnet_get_settings,
1042 	.set_settings		= usbnet_set_settings,
1043 	.get_link		= usbnet_get_link,
1044 	.nway_reset		= usbnet_nway_reset,
1045 	.get_drvinfo		= usbnet_get_drvinfo,
1046 	.get_msglevel		= usbnet_get_msglevel,
1047 	.set_msglevel		= usbnet_set_msglevel,
1048 	.get_ts_info		= ethtool_op_get_ts_info,
1049 };
1050 
1051 /*-------------------------------------------------------------------------*/
1052 
1053 static void __handle_link_change(struct usbnet *dev)
1054 {
1055 	if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
1056 		return;
1057 
1058 	if (!netif_carrier_ok(dev->net)) {
1059 		/* kill URBs for reading packets to save bus bandwidth */
1060 		unlink_urbs(dev, &dev->rxq);
1061 
1062 		/*
1063 		 * tx_timeout will unlink URBs for sending packets and
1064 		 * tx queue is stopped by netcore after link becomes off
1065 		 */
1066 	} else {
1067 		/* submitting URBs for reading packets */
1068 		tasklet_schedule(&dev->bh);
1069 	}
1070 
1071 	/* hard_mtu or rx_urb_size may change during link change */
1072 	usbnet_update_max_qlen(dev);
1073 
1074 	clear_bit(EVENT_LINK_CHANGE, &dev->flags);
1075 }
1076 
1077 static void usbnet_set_rx_mode(struct net_device *net)
1078 {
1079 	struct usbnet		*dev = netdev_priv(net);
1080 
1081 	usbnet_defer_kevent(dev, EVENT_SET_RX_MODE);
1082 }
1083 
1084 static void __handle_set_rx_mode(struct usbnet *dev)
1085 {
1086 	if (dev->driver_info->set_rx_mode)
1087 		(dev->driver_info->set_rx_mode)(dev);
1088 
1089 	clear_bit(EVENT_SET_RX_MODE, &dev->flags);
1090 }
1091 
1092 /* work that cannot be done in interrupt context uses keventd.
1093  *
1094  * NOTE:  with 2.5 we could do more of this using completion callbacks,
1095  * especially now that control transfers can be queued.
1096  */
1097 static void
1098 usbnet_deferred_kevent (struct work_struct *work)
1099 {
1100 	struct usbnet		*dev =
1101 		container_of(work, struct usbnet, kevent);
1102 	int			status;
1103 
1104 	/* usb_clear_halt() needs a thread context */
1105 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
1106 		unlink_urbs (dev, &dev->txq);
1107 		status = usb_autopm_get_interface(dev->intf);
1108 		if (status < 0)
1109 			goto fail_pipe;
1110 		status = usb_clear_halt (dev->udev, dev->out);
1111 		usb_autopm_put_interface(dev->intf);
1112 		if (status < 0 &&
1113 		    status != -EPIPE &&
1114 		    status != -ESHUTDOWN) {
1115 			if (netif_msg_tx_err (dev))
1116 fail_pipe:
1117 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
1118 					   status);
1119 		} else {
1120 			clear_bit (EVENT_TX_HALT, &dev->flags);
1121 			if (status != -ESHUTDOWN)
1122 				netif_wake_queue (dev->net);
1123 		}
1124 	}
1125 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
1126 		unlink_urbs (dev, &dev->rxq);
1127 		status = usb_autopm_get_interface(dev->intf);
1128 		if (status < 0)
1129 			goto fail_halt;
1130 		status = usb_clear_halt (dev->udev, dev->in);
1131 		usb_autopm_put_interface(dev->intf);
1132 		if (status < 0 &&
1133 		    status != -EPIPE &&
1134 		    status != -ESHUTDOWN) {
1135 			if (netif_msg_rx_err (dev))
1136 fail_halt:
1137 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
1138 					   status);
1139 		} else {
1140 			clear_bit (EVENT_RX_HALT, &dev->flags);
1141 			tasklet_schedule (&dev->bh);
1142 		}
1143 	}
1144 
1145 	/* tasklet could resubmit itself forever if memory is tight */
1146 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
1147 		struct urb	*urb = NULL;
1148 		int resched = 1;
1149 
1150 		if (netif_running (dev->net))
1151 			urb = usb_alloc_urb (0, GFP_KERNEL);
1152 		else
1153 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1154 		if (urb != NULL) {
1155 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1156 			status = usb_autopm_get_interface(dev->intf);
1157 			if (status < 0) {
1158 				usb_free_urb(urb);
1159 				goto fail_lowmem;
1160 			}
1161 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
1162 				resched = 0;
1163 			usb_autopm_put_interface(dev->intf);
1164 fail_lowmem:
1165 			if (resched)
1166 				tasklet_schedule (&dev->bh);
1167 		}
1168 	}
1169 
1170 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
1171 		struct driver_info	*info = dev->driver_info;
1172 		int			retval = 0;
1173 
1174 		clear_bit (EVENT_LINK_RESET, &dev->flags);
1175 		status = usb_autopm_get_interface(dev->intf);
1176 		if (status < 0)
1177 			goto skip_reset;
1178 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1179 			usb_autopm_put_interface(dev->intf);
1180 skip_reset:
1181 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1182 				    retval,
1183 				    dev->udev->bus->bus_name,
1184 				    dev->udev->devpath,
1185 				    info->description);
1186 		} else {
1187 			usb_autopm_put_interface(dev->intf);
1188 		}
1189 
1190 		/* handle link change from link resetting */
1191 		__handle_link_change(dev);
1192 	}
1193 
1194 	if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
1195 		__handle_link_change(dev);
1196 
1197 	if (test_bit (EVENT_SET_RX_MODE, &dev->flags))
1198 		__handle_set_rx_mode(dev);
1199 
1200 
1201 	if (dev->flags)
1202 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1203 }
1204 
1205 /*-------------------------------------------------------------------------*/
1206 
1207 static void tx_complete (struct urb *urb)
1208 {
1209 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1210 	struct skb_data		*entry = (struct skb_data *) skb->cb;
1211 	struct usbnet		*dev = entry->dev;
1212 
1213 	if (urb->status == 0) {
1214 		dev->net->stats.tx_packets += entry->packets;
1215 		dev->net->stats.tx_bytes += entry->length;
1216 	} else {
1217 		dev->net->stats.tx_errors++;
1218 
1219 		switch (urb->status) {
1220 		case -EPIPE:
1221 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1222 			break;
1223 
1224 		/* software-driven interface shutdown */
1225 		case -ECONNRESET:		// async unlink
1226 		case -ESHUTDOWN:		// hardware gone
1227 			break;
1228 
1229 		/* like rx, tx gets controller i/o faults during hub_wq
1230 		 * delays and so it uses the same throttling mechanism.
1231 		 */
1232 		case -EPROTO:
1233 		case -ETIME:
1234 		case -EILSEQ:
1235 			usb_mark_last_busy(dev->udev);
1236 			if (!timer_pending (&dev->delay)) {
1237 				mod_timer (&dev->delay,
1238 					jiffies + THROTTLE_JIFFIES);
1239 				netif_dbg(dev, link, dev->net,
1240 					  "tx throttle %d\n", urb->status);
1241 			}
1242 			netif_stop_queue (dev->net);
1243 			break;
1244 		default:
1245 			netif_dbg(dev, tx_err, dev->net,
1246 				  "tx err %d\n", entry->urb->status);
1247 			break;
1248 		}
1249 	}
1250 
1251 	usb_autopm_put_interface_async(dev->intf);
1252 	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1253 }
1254 
1255 /*-------------------------------------------------------------------------*/
1256 
1257 void usbnet_tx_timeout (struct net_device *net)
1258 {
1259 	struct usbnet		*dev = netdev_priv(net);
1260 
1261 	unlink_urbs (dev, &dev->txq);
1262 	tasklet_schedule (&dev->bh);
1263 	/* this needs to be handled individually because the generic layer
1264 	 * doesn't know what is sufficient and could not restore private
1265 	 * information if a remedy of an unconditional reset were used.
1266 	 */
1267 	if (dev->driver_info->recover)
1268 		(dev->driver_info->recover)(dev);
1269 }
1270 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1271 
1272 /*-------------------------------------------------------------------------*/
1273 
1274 static int build_dma_sg(const struct sk_buff *skb, struct urb *urb)
1275 {
1276 	unsigned num_sgs, total_len = 0;
1277 	int i, s = 0;
1278 
1279 	num_sgs = skb_shinfo(skb)->nr_frags + 1;
1280 	if (num_sgs == 1)
1281 		return 0;
1282 
1283 	/* reserve one for zero packet */
1284 	urb->sg = kmalloc((num_sgs + 1) * sizeof(struct scatterlist),
1285 			  GFP_ATOMIC);
1286 	if (!urb->sg)
1287 		return -ENOMEM;
1288 
1289 	urb->num_sgs = num_sgs;
1290 	sg_init_table(urb->sg, urb->num_sgs + 1);
1291 
1292 	sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb));
1293 	total_len += skb_headlen(skb);
1294 
1295 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1296 		struct skb_frag_struct *f = &skb_shinfo(skb)->frags[i];
1297 
1298 		total_len += skb_frag_size(f);
1299 		sg_set_page(&urb->sg[i + s], f->page.p, f->size,
1300 				f->page_offset);
1301 	}
1302 	urb->transfer_buffer_length = total_len;
1303 
1304 	return 1;
1305 }
1306 
1307 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1308 				     struct net_device *net)
1309 {
1310 	struct usbnet		*dev = netdev_priv(net);
1311 	unsigned int			length;
1312 	struct urb		*urb = NULL;
1313 	struct skb_data		*entry;
1314 	struct driver_info	*info = dev->driver_info;
1315 	unsigned long		flags;
1316 	int retval;
1317 
1318 	if (skb)
1319 		skb_tx_timestamp(skb);
1320 
1321 	// some devices want funky USB-level framing, for
1322 	// win32 driver (usually) and/or hardware quirks
1323 	if (info->tx_fixup) {
1324 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1325 		if (!skb) {
1326 			/* packet collected; minidriver waiting for more */
1327 			if (info->flags & FLAG_MULTI_PACKET)
1328 				goto not_drop;
1329 			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1330 			goto drop;
1331 		}
1332 	}
1333 
1334 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1335 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1336 		goto drop;
1337 	}
1338 
1339 	entry = (struct skb_data *) skb->cb;
1340 	entry->urb = urb;
1341 	entry->dev = dev;
1342 
1343 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1344 			skb->data, skb->len, tx_complete, skb);
1345 	if (dev->can_dma_sg) {
1346 		if (build_dma_sg(skb, urb) < 0)
1347 			goto drop;
1348 	}
1349 	length = urb->transfer_buffer_length;
1350 
1351 	/* don't assume the hardware handles USB_ZERO_PACKET
1352 	 * NOTE:  strictly conforming cdc-ether devices should expect
1353 	 * the ZLP here, but ignore the one-byte packet.
1354 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1355 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1356 	 * packet itself if needed.
1357 	 */
1358 	if (length % dev->maxpacket == 0) {
1359 		if (!(info->flags & FLAG_SEND_ZLP)) {
1360 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1361 				length++;
1362 				if (skb_tailroom(skb) && !urb->num_sgs) {
1363 					skb->data[skb->len] = 0;
1364 					__skb_put(skb, 1);
1365 				} else if (urb->num_sgs)
1366 					sg_set_buf(&urb->sg[urb->num_sgs++],
1367 							dev->padding_pkt, 1);
1368 			}
1369 		} else
1370 			urb->transfer_flags |= URB_ZERO_PACKET;
1371 	}
1372 	urb->transfer_buffer_length = length;
1373 
1374 	if (info->flags & FLAG_MULTI_PACKET) {
1375 		/* Driver has set number of packets and a length delta.
1376 		 * Calculate the complete length and ensure that it's
1377 		 * positive.
1378 		 */
1379 		entry->length += length;
1380 		if (WARN_ON_ONCE(entry->length <= 0))
1381 			entry->length = length;
1382 	} else {
1383 		usbnet_set_skb_tx_stats(skb, 1, length);
1384 	}
1385 
1386 	spin_lock_irqsave(&dev->txq.lock, flags);
1387 	retval = usb_autopm_get_interface_async(dev->intf);
1388 	if (retval < 0) {
1389 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1390 		goto drop;
1391 	}
1392 
1393 #ifdef CONFIG_PM
1394 	/* if this triggers the device is still a sleep */
1395 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1396 		/* transmission will be done in resume */
1397 		usb_anchor_urb(urb, &dev->deferred);
1398 		/* no use to process more packets */
1399 		netif_stop_queue(net);
1400 		usb_put_urb(urb);
1401 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1402 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1403 		goto deferred;
1404 	}
1405 #endif
1406 
1407 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1408 	case -EPIPE:
1409 		netif_stop_queue (net);
1410 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1411 		usb_autopm_put_interface_async(dev->intf);
1412 		break;
1413 	default:
1414 		usb_autopm_put_interface_async(dev->intf);
1415 		netif_dbg(dev, tx_err, dev->net,
1416 			  "tx: submit urb err %d\n", retval);
1417 		break;
1418 	case 0:
1419 		netif_trans_update(net);
1420 		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1421 		if (dev->txq.qlen >= TX_QLEN (dev))
1422 			netif_stop_queue (net);
1423 	}
1424 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1425 
1426 	if (retval) {
1427 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1428 drop:
1429 		dev->net->stats.tx_dropped++;
1430 not_drop:
1431 		if (skb)
1432 			dev_kfree_skb_any (skb);
1433 		if (urb) {
1434 			kfree(urb->sg);
1435 			usb_free_urb(urb);
1436 		}
1437 	} else
1438 		netif_dbg(dev, tx_queued, dev->net,
1439 			  "> tx, len %u, type 0x%x\n", length, skb->protocol);
1440 #ifdef CONFIG_PM
1441 deferred:
1442 #endif
1443 	return NETDEV_TX_OK;
1444 }
1445 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1446 
1447 static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1448 {
1449 	struct urb	*urb;
1450 	int		i;
1451 	int		ret = 0;
1452 
1453 	/* don't refill the queue all at once */
1454 	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1455 		urb = usb_alloc_urb(0, flags);
1456 		if (urb != NULL) {
1457 			ret = rx_submit(dev, urb, flags);
1458 			if (ret)
1459 				goto err;
1460 		} else {
1461 			ret = -ENOMEM;
1462 			goto err;
1463 		}
1464 	}
1465 err:
1466 	return ret;
1467 }
1468 
1469 /*-------------------------------------------------------------------------*/
1470 
1471 // tasklet (work deferred from completions, in_irq) or timer
1472 
1473 static void usbnet_bh (unsigned long param)
1474 {
1475 	struct usbnet		*dev = (struct usbnet *) param;
1476 	struct sk_buff		*skb;
1477 	struct skb_data		*entry;
1478 
1479 	while ((skb = skb_dequeue (&dev->done))) {
1480 		entry = (struct skb_data *) skb->cb;
1481 		switch (entry->state) {
1482 		case rx_done:
1483 			entry->state = rx_cleanup;
1484 			rx_process (dev, skb);
1485 			continue;
1486 		case tx_done:
1487 			kfree(entry->urb->sg);
1488 		case rx_cleanup:
1489 			usb_free_urb (entry->urb);
1490 			dev_kfree_skb (skb);
1491 			continue;
1492 		default:
1493 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1494 		}
1495 	}
1496 
1497 	/* restart RX again after disabling due to high error rate */
1498 	clear_bit(EVENT_RX_KILL, &dev->flags);
1499 
1500 	/* waiting for all pending urbs to complete?
1501 	 * only then can we forgo submitting anew
1502 	 */
1503 	if (waitqueue_active(&dev->wait)) {
1504 		if (dev->txq.qlen + dev->rxq.qlen + dev->done.qlen == 0)
1505 			wake_up_all(&dev->wait);
1506 
1507 	// or are we maybe short a few urbs?
1508 	} else if (netif_running (dev->net) &&
1509 		   netif_device_present (dev->net) &&
1510 		   netif_carrier_ok(dev->net) &&
1511 		   !timer_pending(&dev->delay) &&
1512 		   !test_bit(EVENT_RX_PAUSED, &dev->flags) &&
1513 		   !test_bit(EVENT_RX_HALT, &dev->flags)) {
1514 		int	temp = dev->rxq.qlen;
1515 
1516 		if (temp < RX_QLEN(dev)) {
1517 			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1518 				return;
1519 			if (temp != dev->rxq.qlen)
1520 				netif_dbg(dev, link, dev->net,
1521 					  "rxqlen %d --> %d\n",
1522 					  temp, dev->rxq.qlen);
1523 			if (dev->rxq.qlen < RX_QLEN(dev))
1524 				tasklet_schedule (&dev->bh);
1525 		}
1526 		if (dev->txq.qlen < TX_QLEN (dev))
1527 			netif_wake_queue (dev->net);
1528 	}
1529 }
1530 
1531 
1532 /*-------------------------------------------------------------------------
1533  *
1534  * USB Device Driver support
1535  *
1536  *-------------------------------------------------------------------------*/
1537 
1538 // precondition: never called in_interrupt
1539 
1540 void usbnet_disconnect (struct usb_interface *intf)
1541 {
1542 	struct usbnet		*dev;
1543 	struct usb_device	*xdev;
1544 	struct net_device	*net;
1545 
1546 	dev = usb_get_intfdata(intf);
1547 	usb_set_intfdata(intf, NULL);
1548 	if (!dev)
1549 		return;
1550 
1551 	xdev = interface_to_usbdev (intf);
1552 
1553 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1554 		   intf->dev.driver->name,
1555 		   xdev->bus->bus_name, xdev->devpath,
1556 		   dev->driver_info->description);
1557 
1558 	net = dev->net;
1559 	unregister_netdev (net);
1560 
1561 	cancel_work_sync(&dev->kevent);
1562 
1563 	usb_scuttle_anchored_urbs(&dev->deferred);
1564 
1565 	if (dev->driver_info->unbind)
1566 		dev->driver_info->unbind (dev, intf);
1567 
1568 	usb_kill_urb(dev->interrupt);
1569 	usb_free_urb(dev->interrupt);
1570 	kfree(dev->padding_pkt);
1571 
1572 	free_netdev(net);
1573 }
1574 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1575 
1576 static const struct net_device_ops usbnet_netdev_ops = {
1577 	.ndo_open		= usbnet_open,
1578 	.ndo_stop		= usbnet_stop,
1579 	.ndo_start_xmit		= usbnet_start_xmit,
1580 	.ndo_tx_timeout		= usbnet_tx_timeout,
1581 	.ndo_set_rx_mode	= usbnet_set_rx_mode,
1582 	.ndo_change_mtu		= usbnet_change_mtu,
1583 	.ndo_set_mac_address 	= eth_mac_addr,
1584 	.ndo_validate_addr	= eth_validate_addr,
1585 };
1586 
1587 /*-------------------------------------------------------------------------*/
1588 
1589 // precondition: never called in_interrupt
1590 
1591 static struct device_type wlan_type = {
1592 	.name	= "wlan",
1593 };
1594 
1595 static struct device_type wwan_type = {
1596 	.name	= "wwan",
1597 };
1598 
1599 int
1600 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1601 {
1602 	struct usbnet			*dev;
1603 	struct net_device		*net;
1604 	struct usb_host_interface	*interface;
1605 	struct driver_info		*info;
1606 	struct usb_device		*xdev;
1607 	int				status;
1608 	const char			*name;
1609 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1610 
1611 	/* usbnet already took usb runtime pm, so have to enable the feature
1612 	 * for usb interface, otherwise usb_autopm_get_interface may return
1613 	 * failure if RUNTIME_PM is enabled.
1614 	 */
1615 	if (!driver->supports_autosuspend) {
1616 		driver->supports_autosuspend = 1;
1617 		pm_runtime_enable(&udev->dev);
1618 	}
1619 
1620 	name = udev->dev.driver->name;
1621 	info = (struct driver_info *) prod->driver_info;
1622 	if (!info) {
1623 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1624 		return -ENODEV;
1625 	}
1626 	xdev = interface_to_usbdev (udev);
1627 	interface = udev->cur_altsetting;
1628 
1629 	status = -ENOMEM;
1630 
1631 	// set up our own records
1632 	net = alloc_etherdev(sizeof(*dev));
1633 	if (!net)
1634 		goto out;
1635 
1636 	/* netdev_printk() needs this so do it as early as possible */
1637 	SET_NETDEV_DEV(net, &udev->dev);
1638 
1639 	dev = netdev_priv(net);
1640 	dev->udev = xdev;
1641 	dev->intf = udev;
1642 	dev->driver_info = info;
1643 	dev->driver_name = name;
1644 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1645 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1646 	init_waitqueue_head(&dev->wait);
1647 	skb_queue_head_init (&dev->rxq);
1648 	skb_queue_head_init (&dev->txq);
1649 	skb_queue_head_init (&dev->done);
1650 	skb_queue_head_init(&dev->rxq_pause);
1651 	dev->bh.func = usbnet_bh;
1652 	dev->bh.data = (unsigned long) dev;
1653 	INIT_WORK (&dev->kevent, usbnet_deferred_kevent);
1654 	init_usb_anchor(&dev->deferred);
1655 	dev->delay.function = usbnet_bh;
1656 	dev->delay.data = (unsigned long) dev;
1657 	init_timer (&dev->delay);
1658 	mutex_init (&dev->phy_mutex);
1659 	mutex_init(&dev->interrupt_mutex);
1660 	dev->interrupt_count = 0;
1661 
1662 	dev->net = net;
1663 	strcpy (net->name, "usb%d");
1664 	memcpy (net->dev_addr, node_id, sizeof node_id);
1665 
1666 	/* rx and tx sides can use different message sizes;
1667 	 * bind() should set rx_urb_size in that case.
1668 	 */
1669 	dev->hard_mtu = net->mtu + net->hard_header_len;
1670 	net->min_mtu = 0;
1671 	net->max_mtu = ETH_MAX_MTU;
1672 
1673 	net->netdev_ops = &usbnet_netdev_ops;
1674 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1675 	net->ethtool_ops = &usbnet_ethtool_ops;
1676 
1677 	// allow device-specific bind/init procedures
1678 	// NOTE net->name still not usable ...
1679 	if (info->bind) {
1680 		status = info->bind (dev, udev);
1681 		if (status < 0)
1682 			goto out1;
1683 
1684 		// heuristic:  "usb%d" for links we know are two-host,
1685 		// else "eth%d" when there's reasonable doubt.  userspace
1686 		// can rename the link if it knows better.
1687 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1688 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1689 		     (net->dev_addr [0] & 0x02) == 0))
1690 			strcpy (net->name, "eth%d");
1691 		/* WLAN devices should always be named "wlan%d" */
1692 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1693 			strcpy(net->name, "wlan%d");
1694 		/* WWAN devices should always be named "wwan%d" */
1695 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1696 			strcpy(net->name, "wwan%d");
1697 
1698 		/* devices that cannot do ARP */
1699 		if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1700 			net->flags |= IFF_NOARP;
1701 
1702 		/* maybe the remote can't receive an Ethernet MTU */
1703 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1704 			net->mtu = dev->hard_mtu - net->hard_header_len;
1705 	} else if (!info->in || !info->out)
1706 		status = usbnet_get_endpoints (dev, udev);
1707 	else {
1708 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1709 		dev->out = usb_sndbulkpipe (xdev, info->out);
1710 		if (!(info->flags & FLAG_NO_SETINT))
1711 			status = usb_set_interface (xdev,
1712 				interface->desc.bInterfaceNumber,
1713 				interface->desc.bAlternateSetting);
1714 		else
1715 			status = 0;
1716 
1717 	}
1718 	if (status >= 0 && dev->status)
1719 		status = init_status (dev, udev);
1720 	if (status < 0)
1721 		goto out3;
1722 
1723 	if (!dev->rx_urb_size)
1724 		dev->rx_urb_size = dev->hard_mtu;
1725 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1726 
1727 	/* let userspace know we have a random address */
1728 	if (ether_addr_equal(net->dev_addr, node_id))
1729 		net->addr_assign_type = NET_ADDR_RANDOM;
1730 
1731 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1732 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1733 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1734 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1735 
1736 	/* initialize max rx_qlen and tx_qlen */
1737 	usbnet_update_max_qlen(dev);
1738 
1739 	if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&
1740 		!(info->flags & FLAG_MULTI_PACKET)) {
1741 		dev->padding_pkt = kzalloc(1, GFP_KERNEL);
1742 		if (!dev->padding_pkt) {
1743 			status = -ENOMEM;
1744 			goto out4;
1745 		}
1746 	}
1747 
1748 	status = register_netdev (net);
1749 	if (status)
1750 		goto out5;
1751 	netif_info(dev, probe, dev->net,
1752 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1753 		   udev->dev.driver->name,
1754 		   xdev->bus->bus_name, xdev->devpath,
1755 		   dev->driver_info->description,
1756 		   net->dev_addr);
1757 
1758 	// ok, it's ready to go.
1759 	usb_set_intfdata (udev, dev);
1760 
1761 	netif_device_attach (net);
1762 
1763 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1764 		usbnet_link_change(dev, 0, 0);
1765 
1766 	return 0;
1767 
1768 out5:
1769 	kfree(dev->padding_pkt);
1770 out4:
1771 	usb_free_urb(dev->interrupt);
1772 out3:
1773 	if (info->unbind)
1774 		info->unbind (dev, udev);
1775 out1:
1776 	/* subdrivers must undo all they did in bind() if they
1777 	 * fail it, but we may fail later and a deferred kevent
1778 	 * may trigger an error resubmitting itself and, worse,
1779 	 * schedule a timer. So we kill it all just in case.
1780 	 */
1781 	cancel_work_sync(&dev->kevent);
1782 	del_timer_sync(&dev->delay);
1783 	free_netdev(net);
1784 out:
1785 	return status;
1786 }
1787 EXPORT_SYMBOL_GPL(usbnet_probe);
1788 
1789 /*-------------------------------------------------------------------------*/
1790 
1791 /*
1792  * suspend the whole driver as soon as the first interface is suspended
1793  * resume only when the last interface is resumed
1794  */
1795 
1796 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1797 {
1798 	struct usbnet		*dev = usb_get_intfdata(intf);
1799 
1800 	if (!dev->suspend_count++) {
1801 		spin_lock_irq(&dev->txq.lock);
1802 		/* don't autosuspend while transmitting */
1803 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1804 			dev->suspend_count--;
1805 			spin_unlock_irq(&dev->txq.lock);
1806 			return -EBUSY;
1807 		} else {
1808 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1809 			spin_unlock_irq(&dev->txq.lock);
1810 		}
1811 		/*
1812 		 * accelerate emptying of the rx and queues, to avoid
1813 		 * having everything error out.
1814 		 */
1815 		netif_device_detach (dev->net);
1816 		usbnet_terminate_urbs(dev);
1817 		__usbnet_status_stop_force(dev);
1818 
1819 		/*
1820 		 * reattach so runtime management can use and
1821 		 * wake the device
1822 		 */
1823 		netif_device_attach (dev->net);
1824 	}
1825 	return 0;
1826 }
1827 EXPORT_SYMBOL_GPL(usbnet_suspend);
1828 
1829 int usbnet_resume (struct usb_interface *intf)
1830 {
1831 	struct usbnet		*dev = usb_get_intfdata(intf);
1832 	struct sk_buff          *skb;
1833 	struct urb              *res;
1834 	int                     retval;
1835 
1836 	if (!--dev->suspend_count) {
1837 		/* resume interrupt URB if it was previously submitted */
1838 		__usbnet_status_start_force(dev, GFP_NOIO);
1839 
1840 		spin_lock_irq(&dev->txq.lock);
1841 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1842 
1843 			skb = (struct sk_buff *)res->context;
1844 			retval = usb_submit_urb(res, GFP_ATOMIC);
1845 			if (retval < 0) {
1846 				dev_kfree_skb_any(skb);
1847 				kfree(res->sg);
1848 				usb_free_urb(res);
1849 				usb_autopm_put_interface_async(dev->intf);
1850 			} else {
1851 				netif_trans_update(dev->net);
1852 				__skb_queue_tail(&dev->txq, skb);
1853 			}
1854 		}
1855 
1856 		smp_mb();
1857 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1858 		spin_unlock_irq(&dev->txq.lock);
1859 
1860 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1861 			/* handle remote wakeup ASAP
1862 			 * we cannot race against stop
1863 			 */
1864 			if (netif_device_present(dev->net) &&
1865 				!timer_pending(&dev->delay) &&
1866 				!test_bit(EVENT_RX_HALT, &dev->flags))
1867 					rx_alloc_submit(dev, GFP_NOIO);
1868 
1869 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1870 				netif_tx_wake_all_queues(dev->net);
1871 			tasklet_schedule (&dev->bh);
1872 		}
1873 	}
1874 
1875 	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1876 		usb_autopm_get_interface_no_resume(intf);
1877 
1878 	return 0;
1879 }
1880 EXPORT_SYMBOL_GPL(usbnet_resume);
1881 
1882 /*
1883  * Either a subdriver implements manage_power, then it is assumed to always
1884  * be ready to be suspended or it reports the readiness to be suspended
1885  * explicitly
1886  */
1887 void usbnet_device_suggests_idle(struct usbnet *dev)
1888 {
1889 	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1890 		dev->intf->needs_remote_wakeup = 1;
1891 		usb_autopm_put_interface_async(dev->intf);
1892 	}
1893 }
1894 EXPORT_SYMBOL(usbnet_device_suggests_idle);
1895 
1896 /*
1897  * For devices that can do without special commands
1898  */
1899 int usbnet_manage_power(struct usbnet *dev, int on)
1900 {
1901 	dev->intf->needs_remote_wakeup = on;
1902 	return 0;
1903 }
1904 EXPORT_SYMBOL(usbnet_manage_power);
1905 
1906 void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
1907 {
1908 	/* update link after link is reseted */
1909 	if (link && !need_reset)
1910 		netif_carrier_on(dev->net);
1911 	else
1912 		netif_carrier_off(dev->net);
1913 
1914 	if (need_reset && link)
1915 		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
1916 	else
1917 		usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
1918 }
1919 EXPORT_SYMBOL(usbnet_link_change);
1920 
1921 /*-------------------------------------------------------------------------*/
1922 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1923 			     u16 value, u16 index, void *data, u16 size)
1924 {
1925 	void *buf = NULL;
1926 	int err = -ENOMEM;
1927 
1928 	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
1929 		   " value=0x%04x index=0x%04x size=%d\n",
1930 		   cmd, reqtype, value, index, size);
1931 
1932 	if (data) {
1933 		buf = kmalloc(size, GFP_KERNEL);
1934 		if (!buf)
1935 			goto out;
1936 	}
1937 
1938 	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
1939 			      cmd, reqtype, value, index, buf, size,
1940 			      USB_CTRL_GET_TIMEOUT);
1941 	if (err > 0 && err <= size)
1942 		memcpy(data, buf, err);
1943 	kfree(buf);
1944 out:
1945 	return err;
1946 }
1947 
1948 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1949 			      u16 value, u16 index, const void *data,
1950 			      u16 size)
1951 {
1952 	void *buf = NULL;
1953 	int err = -ENOMEM;
1954 
1955 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
1956 		   " value=0x%04x index=0x%04x size=%d\n",
1957 		   cmd, reqtype, value, index, size);
1958 
1959 	if (data) {
1960 		buf = kmemdup(data, size, GFP_KERNEL);
1961 		if (!buf)
1962 			goto out;
1963 	}
1964 
1965 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
1966 			      cmd, reqtype, value, index, buf, size,
1967 			      USB_CTRL_SET_TIMEOUT);
1968 	kfree(buf);
1969 
1970 out:
1971 	return err;
1972 }
1973 
1974 /*
1975  * The function can't be called inside suspend/resume callback,
1976  * otherwise deadlock will be caused.
1977  */
1978 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1979 		    u16 value, u16 index, void *data, u16 size)
1980 {
1981 	int ret;
1982 
1983 	if (usb_autopm_get_interface(dev->intf) < 0)
1984 		return -ENODEV;
1985 	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
1986 				data, size);
1987 	usb_autopm_put_interface(dev->intf);
1988 	return ret;
1989 }
1990 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
1991 
1992 /*
1993  * The function can't be called inside suspend/resume callback,
1994  * otherwise deadlock will be caused.
1995  */
1996 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1997 		     u16 value, u16 index, const void *data, u16 size)
1998 {
1999 	int ret;
2000 
2001 	if (usb_autopm_get_interface(dev->intf) < 0)
2002 		return -ENODEV;
2003 	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2004 				 data, size);
2005 	usb_autopm_put_interface(dev->intf);
2006 	return ret;
2007 }
2008 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
2009 
2010 /*
2011  * The function can be called inside suspend/resume callback safely
2012  * and should only be called by suspend/resume callback generally.
2013  */
2014 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2015 			  u16 value, u16 index, void *data, u16 size)
2016 {
2017 	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2018 				 data, size);
2019 }
2020 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
2021 
2022 /*
2023  * The function can be called inside suspend/resume callback safely
2024  * and should only be called by suspend/resume callback generally.
2025  */
2026 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2027 			  u16 value, u16 index, const void *data,
2028 			  u16 size)
2029 {
2030 	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2031 				  data, size);
2032 }
2033 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
2034 
2035 static void usbnet_async_cmd_cb(struct urb *urb)
2036 {
2037 	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
2038 	int status = urb->status;
2039 
2040 	if (status < 0)
2041 		dev_dbg(&urb->dev->dev, "%s failed with %d",
2042 			__func__, status);
2043 
2044 	kfree(req);
2045 	usb_free_urb(urb);
2046 }
2047 
2048 /*
2049  * The caller must make sure that device can't be put into suspend
2050  * state until the control URB completes.
2051  */
2052 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
2053 			   u16 value, u16 index, const void *data, u16 size)
2054 {
2055 	struct usb_ctrlrequest *req = NULL;
2056 	struct urb *urb;
2057 	int err = -ENOMEM;
2058 	void *buf = NULL;
2059 
2060 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2061 		   " value=0x%04x index=0x%04x size=%d\n",
2062 		   cmd, reqtype, value, index, size);
2063 
2064 	urb = usb_alloc_urb(0, GFP_ATOMIC);
2065 	if (!urb)
2066 		goto fail;
2067 
2068 	if (data) {
2069 		buf = kmemdup(data, size, GFP_ATOMIC);
2070 		if (!buf) {
2071 			netdev_err(dev->net, "Error allocating buffer"
2072 				   " in %s!\n", __func__);
2073 			goto fail_free;
2074 		}
2075 	}
2076 
2077 	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
2078 	if (!req)
2079 		goto fail_free_buf;
2080 
2081 	req->bRequestType = reqtype;
2082 	req->bRequest = cmd;
2083 	req->wValue = cpu_to_le16(value);
2084 	req->wIndex = cpu_to_le16(index);
2085 	req->wLength = cpu_to_le16(size);
2086 
2087 	usb_fill_control_urb(urb, dev->udev,
2088 			     usb_sndctrlpipe(dev->udev, 0),
2089 			     (void *)req, buf, size,
2090 			     usbnet_async_cmd_cb, req);
2091 	urb->transfer_flags |= URB_FREE_BUFFER;
2092 
2093 	err = usb_submit_urb(urb, GFP_ATOMIC);
2094 	if (err < 0) {
2095 		netdev_err(dev->net, "Error submitting the control"
2096 			   " message: status=%d\n", err);
2097 		goto fail_free;
2098 	}
2099 	return 0;
2100 
2101 fail_free_buf:
2102 	kfree(buf);
2103 fail_free:
2104 	kfree(req);
2105 	usb_free_urb(urb);
2106 fail:
2107 	return err;
2108 
2109 }
2110 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
2111 /*-------------------------------------------------------------------------*/
2112 
2113 static int __init usbnet_init(void)
2114 {
2115 	/* Compiler should optimize this out. */
2116 	BUILD_BUG_ON(
2117 		FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
2118 
2119 	eth_random_addr(node_id);
2120 	return 0;
2121 }
2122 module_init(usbnet_init);
2123 
2124 static void __exit usbnet_exit(void)
2125 {
2126 }
2127 module_exit(usbnet_exit);
2128 
2129 MODULE_AUTHOR("David Brownell");
2130 MODULE_DESCRIPTION("USB network driver framework");
2131 MODULE_LICENSE("GPL");
2132