xref: /linux/drivers/net/usb/usbnet.c (revision 0883c2c06fb5bcf5b9e008270827e63c09a88c1e)
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/usb/cdc.h>
46 #include <linux/slab.h>
47 #include <linux/kernel.h>
48 #include <linux/pm_runtime.h>
49 
50 #define DRIVER_VERSION		"22-Aug-2005"
51 
52 
53 /*-------------------------------------------------------------------------*/
54 
55 /*
56  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
57  * Several dozen bytes of IPv4 data can fit in two such transactions.
58  * One maximum size Ethernet packet takes twenty four of them.
59  * For high speed, each frame comfortably fits almost 36 max size
60  * Ethernet packets (so queues should be bigger).
61  *
62  * The goal is to let the USB host controller be busy for 5msec or
63  * more before an irq is required, under load.  Jumbograms change
64  * the equation.
65  */
66 #define	MAX_QUEUE_MEMORY	(60 * 1518)
67 #define	RX_QLEN(dev)		((dev)->rx_qlen)
68 #define	TX_QLEN(dev)		((dev)->tx_qlen)
69 
70 // reawaken network queue this soon after stopping; else watchdog barks
71 #define TX_TIMEOUT_JIFFIES	(5*HZ)
72 
73 /* throttle rx/tx briefly after some faults, so hub_wq might disconnect()
74  * us (it polls at HZ/4 usually) before we report too many false errors.
75  */
76 #define THROTTLE_JIFFIES	(HZ/8)
77 
78 // between wakeups
79 #define UNLINK_TIMEOUT_MS	3
80 
81 /*-------------------------------------------------------------------------*/
82 
83 // randomly generated ethernet address
84 static u8	node_id [ETH_ALEN];
85 
86 static const char driver_name [] = "usbnet";
87 
88 /* use ethtool to change the level for any given device */
89 static int msg_level = -1;
90 module_param (msg_level, int, 0);
91 MODULE_PARM_DESC (msg_level, "Override default message level");
92 
93 /*-------------------------------------------------------------------------*/
94 
95 /* handles CDC Ethernet and many other network "bulk data" interfaces */
96 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
97 {
98 	int				tmp;
99 	struct usb_host_interface	*alt = NULL;
100 	struct usb_host_endpoint	*in = NULL, *out = NULL;
101 	struct usb_host_endpoint	*status = NULL;
102 
103 	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
104 		unsigned	ep;
105 
106 		in = out = status = NULL;
107 		alt = intf->altsetting + tmp;
108 
109 		/* take the first altsetting with in-bulk + out-bulk;
110 		 * remember any status endpoint, just in case;
111 		 * ignore other endpoints and altsettings.
112 		 */
113 		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
114 			struct usb_host_endpoint	*e;
115 			int				intr = 0;
116 
117 			e = alt->endpoint + ep;
118 			switch (e->desc.bmAttributes) {
119 			case USB_ENDPOINT_XFER_INT:
120 				if (!usb_endpoint_dir_in(&e->desc))
121 					continue;
122 				intr = 1;
123 				/* FALLTHROUGH */
124 			case USB_ENDPOINT_XFER_BULK:
125 				break;
126 			default:
127 				continue;
128 			}
129 			if (usb_endpoint_dir_in(&e->desc)) {
130 				if (!intr && !in)
131 					in = e;
132 				else if (intr && !status)
133 					status = e;
134 			} else {
135 				if (!out)
136 					out = e;
137 			}
138 		}
139 		if (in && out)
140 			break;
141 	}
142 	if (!alt || !in || !out)
143 		return -EINVAL;
144 
145 	if (alt->desc.bAlternateSetting != 0 ||
146 	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
147 		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
148 				alt->desc.bAlternateSetting);
149 		if (tmp < 0)
150 			return tmp;
151 	}
152 
153 	dev->in = usb_rcvbulkpipe (dev->udev,
154 			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
155 	dev->out = usb_sndbulkpipe (dev->udev,
156 			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
157 	dev->status = status;
158 	return 0;
159 }
160 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
161 
162 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
163 {
164 	int 		tmp = -1, ret;
165 	unsigned char	buf [13];
166 
167 	ret = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
168 	if (ret == 12)
169 		tmp = hex2bin(dev->net->dev_addr, buf, 6);
170 	if (tmp < 0) {
171 		dev_dbg(&dev->udev->dev,
172 			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
173 		if (ret >= 0)
174 			ret = -EINVAL;
175 		return ret;
176 	}
177 	return 0;
178 }
179 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
180 
181 static void intr_complete (struct urb *urb)
182 {
183 	struct usbnet	*dev = urb->context;
184 	int		status = urb->status;
185 
186 	switch (status) {
187 	/* success */
188 	case 0:
189 		dev->driver_info->status(dev, urb);
190 		break;
191 
192 	/* software-driven interface shutdown */
193 	case -ENOENT:		/* urb killed */
194 	case -ESHUTDOWN:	/* hardware gone */
195 		netif_dbg(dev, ifdown, dev->net,
196 			  "intr shutdown, code %d\n", status);
197 		return;
198 
199 	/* NOTE:  not throttling like RX/TX, since this endpoint
200 	 * already polls infrequently
201 	 */
202 	default:
203 		netdev_dbg(dev->net, "intr status %d\n", status);
204 		break;
205 	}
206 
207 	status = usb_submit_urb (urb, GFP_ATOMIC);
208 	if (status != 0)
209 		netif_err(dev, timer, dev->net,
210 			  "intr resubmit --> %d\n", status);
211 }
212 
213 static int init_status (struct usbnet *dev, struct usb_interface *intf)
214 {
215 	char		*buf = NULL;
216 	unsigned	pipe = 0;
217 	unsigned	maxp;
218 	unsigned	period;
219 
220 	if (!dev->driver_info->status)
221 		return 0;
222 
223 	pipe = usb_rcvintpipe (dev->udev,
224 			dev->status->desc.bEndpointAddress
225 				& USB_ENDPOINT_NUMBER_MASK);
226 	maxp = usb_maxpacket (dev->udev, pipe, 0);
227 
228 	/* avoid 1 msec chatter:  min 8 msec poll rate */
229 	period = max ((int) dev->status->desc.bInterval,
230 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
231 
232 	buf = kmalloc (maxp, GFP_KERNEL);
233 	if (buf) {
234 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
235 		if (!dev->interrupt) {
236 			kfree (buf);
237 			return -ENOMEM;
238 		} else {
239 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
240 				buf, maxp, intr_complete, dev, period);
241 			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
242 			dev_dbg(&intf->dev,
243 				"status ep%din, %d bytes period %d\n",
244 				usb_pipeendpoint(pipe), maxp, period);
245 		}
246 	}
247 	return 0;
248 }
249 
250 /* Submit the interrupt URB if not previously submitted, increasing refcount */
251 int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
252 {
253 	int ret = 0;
254 
255 	WARN_ON_ONCE(dev->interrupt == NULL);
256 	if (dev->interrupt) {
257 		mutex_lock(&dev->interrupt_mutex);
258 
259 		if (++dev->interrupt_count == 1)
260 			ret = usb_submit_urb(dev->interrupt, mem_flags);
261 
262 		dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
263 			dev->interrupt_count);
264 		mutex_unlock(&dev->interrupt_mutex);
265 	}
266 	return ret;
267 }
268 EXPORT_SYMBOL_GPL(usbnet_status_start);
269 
270 /* For resume; submit interrupt URB if previously submitted */
271 static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
272 {
273 	int ret = 0;
274 
275 	mutex_lock(&dev->interrupt_mutex);
276 	if (dev->interrupt_count) {
277 		ret = usb_submit_urb(dev->interrupt, mem_flags);
278 		dev_dbg(&dev->udev->dev,
279 			"submitted interrupt URB for resume\n");
280 	}
281 	mutex_unlock(&dev->interrupt_mutex);
282 	return ret;
283 }
284 
285 /* Kill the interrupt URB if all submitters want it killed */
286 void usbnet_status_stop(struct usbnet *dev)
287 {
288 	if (dev->interrupt) {
289 		mutex_lock(&dev->interrupt_mutex);
290 		WARN_ON(dev->interrupt_count == 0);
291 
292 		if (dev->interrupt_count && --dev->interrupt_count == 0)
293 			usb_kill_urb(dev->interrupt);
294 
295 		dev_dbg(&dev->udev->dev,
296 			"decremented interrupt URB count to %d\n",
297 			dev->interrupt_count);
298 		mutex_unlock(&dev->interrupt_mutex);
299 	}
300 }
301 EXPORT_SYMBOL_GPL(usbnet_status_stop);
302 
303 /* For suspend; always kill interrupt URB */
304 static void __usbnet_status_stop_force(struct usbnet *dev)
305 {
306 	if (dev->interrupt) {
307 		mutex_lock(&dev->interrupt_mutex);
308 		usb_kill_urb(dev->interrupt);
309 		dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
310 		mutex_unlock(&dev->interrupt_mutex);
311 	}
312 }
313 
314 /* Passes this packet up the stack, updating its accounting.
315  * Some link protocols batch packets, so their rx_fixup paths
316  * can return clones as well as just modify the original skb.
317  */
318 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
319 {
320 	int	status;
321 
322 	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
323 		skb_queue_tail(&dev->rxq_pause, skb);
324 		return;
325 	}
326 
327 	/* only update if unset to allow minidriver rx_fixup override */
328 	if (skb->protocol == 0)
329 		skb->protocol = eth_type_trans (skb, dev->net);
330 
331 	dev->net->stats.rx_packets++;
332 	dev->net->stats.rx_bytes += skb->len;
333 
334 	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
335 		  skb->len + sizeof (struct ethhdr), skb->protocol);
336 	memset (skb->cb, 0, sizeof (struct skb_data));
337 
338 	if (skb_defer_rx_timestamp(skb))
339 		return;
340 
341 	status = netif_rx (skb);
342 	if (status != NET_RX_SUCCESS)
343 		netif_dbg(dev, rx_err, dev->net,
344 			  "netif_rx status %d\n", status);
345 }
346 EXPORT_SYMBOL_GPL(usbnet_skb_return);
347 
348 /* must be called if hard_mtu or rx_urb_size changed */
349 void usbnet_update_max_qlen(struct usbnet *dev)
350 {
351 	enum usb_device_speed speed = dev->udev->speed;
352 
353 	switch (speed) {
354 	case USB_SPEED_HIGH:
355 		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
356 		dev->tx_qlen = MAX_QUEUE_MEMORY / dev->hard_mtu;
357 		break;
358 	case USB_SPEED_SUPER:
359 	case USB_SPEED_SUPER_PLUS:
360 		/*
361 		 * Not take default 5ms qlen for super speed HC to
362 		 * save memory, and iperf tests show 2.5ms qlen can
363 		 * work well
364 		 */
365 		dev->rx_qlen = 5 * MAX_QUEUE_MEMORY / dev->rx_urb_size;
366 		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
367 		break;
368 	default:
369 		dev->rx_qlen = dev->tx_qlen = 4;
370 	}
371 }
372 EXPORT_SYMBOL_GPL(usbnet_update_max_qlen);
373 
374 
375 /*-------------------------------------------------------------------------
376  *
377  * Network Device Driver (peer link to "Host Device", from USB host)
378  *
379  *-------------------------------------------------------------------------*/
380 
381 int usbnet_change_mtu (struct net_device *net, int new_mtu)
382 {
383 	struct usbnet	*dev = netdev_priv(net);
384 	int		ll_mtu = new_mtu + net->hard_header_len;
385 	int		old_hard_mtu = dev->hard_mtu;
386 	int		old_rx_urb_size = dev->rx_urb_size;
387 
388 	if (new_mtu <= 0)
389 		return -EINVAL;
390 	// no second zero-length packet read wanted after mtu-sized packets
391 	if ((ll_mtu % dev->maxpacket) == 0)
392 		return -EDOM;
393 	net->mtu = new_mtu;
394 
395 	dev->hard_mtu = net->mtu + net->hard_header_len;
396 	if (dev->rx_urb_size == old_hard_mtu) {
397 		dev->rx_urb_size = dev->hard_mtu;
398 		if (dev->rx_urb_size > old_rx_urb_size)
399 			usbnet_unlink_rx_urbs(dev);
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_HALT, &dev->flags)) {
1513 		int	temp = dev->rxq.qlen;
1514 
1515 		if (temp < RX_QLEN(dev)) {
1516 			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1517 				return;
1518 			if (temp != dev->rxq.qlen)
1519 				netif_dbg(dev, link, dev->net,
1520 					  "rxqlen %d --> %d\n",
1521 					  temp, dev->rxq.qlen);
1522 			if (dev->rxq.qlen < RX_QLEN(dev))
1523 				tasklet_schedule (&dev->bh);
1524 		}
1525 		if (dev->txq.qlen < TX_QLEN (dev))
1526 			netif_wake_queue (dev->net);
1527 	}
1528 }
1529 
1530 
1531 /*-------------------------------------------------------------------------
1532  *
1533  * USB Device Driver support
1534  *
1535  *-------------------------------------------------------------------------*/
1536 
1537 // precondition: never called in_interrupt
1538 
1539 void usbnet_disconnect (struct usb_interface *intf)
1540 {
1541 	struct usbnet		*dev;
1542 	struct usb_device	*xdev;
1543 	struct net_device	*net;
1544 
1545 	dev = usb_get_intfdata(intf);
1546 	usb_set_intfdata(intf, NULL);
1547 	if (!dev)
1548 		return;
1549 
1550 	xdev = interface_to_usbdev (intf);
1551 
1552 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1553 		   intf->dev.driver->name,
1554 		   xdev->bus->bus_name, xdev->devpath,
1555 		   dev->driver_info->description);
1556 
1557 	net = dev->net;
1558 	unregister_netdev (net);
1559 
1560 	cancel_work_sync(&dev->kevent);
1561 
1562 	usb_scuttle_anchored_urbs(&dev->deferred);
1563 
1564 	if (dev->driver_info->unbind)
1565 		dev->driver_info->unbind (dev, intf);
1566 
1567 	usb_kill_urb(dev->interrupt);
1568 	usb_free_urb(dev->interrupt);
1569 	kfree(dev->padding_pkt);
1570 
1571 	free_netdev(net);
1572 }
1573 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1574 
1575 static const struct net_device_ops usbnet_netdev_ops = {
1576 	.ndo_open		= usbnet_open,
1577 	.ndo_stop		= usbnet_stop,
1578 	.ndo_start_xmit		= usbnet_start_xmit,
1579 	.ndo_tx_timeout		= usbnet_tx_timeout,
1580 	.ndo_set_rx_mode	= usbnet_set_rx_mode,
1581 	.ndo_change_mtu		= usbnet_change_mtu,
1582 	.ndo_set_mac_address 	= eth_mac_addr,
1583 	.ndo_validate_addr	= eth_validate_addr,
1584 };
1585 
1586 /*-------------------------------------------------------------------------*/
1587 
1588 // precondition: never called in_interrupt
1589 
1590 static struct device_type wlan_type = {
1591 	.name	= "wlan",
1592 };
1593 
1594 static struct device_type wwan_type = {
1595 	.name	= "wwan",
1596 };
1597 
1598 int
1599 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1600 {
1601 	struct usbnet			*dev;
1602 	struct net_device		*net;
1603 	struct usb_host_interface	*interface;
1604 	struct driver_info		*info;
1605 	struct usb_device		*xdev;
1606 	int				status;
1607 	const char			*name;
1608 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1609 
1610 	/* usbnet already took usb runtime pm, so have to enable the feature
1611 	 * for usb interface, otherwise usb_autopm_get_interface may return
1612 	 * failure if RUNTIME_PM is enabled.
1613 	 */
1614 	if (!driver->supports_autosuspend) {
1615 		driver->supports_autosuspend = 1;
1616 		pm_runtime_enable(&udev->dev);
1617 	}
1618 
1619 	name = udev->dev.driver->name;
1620 	info = (struct driver_info *) prod->driver_info;
1621 	if (!info) {
1622 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1623 		return -ENODEV;
1624 	}
1625 	xdev = interface_to_usbdev (udev);
1626 	interface = udev->cur_altsetting;
1627 
1628 	status = -ENOMEM;
1629 
1630 	// set up our own records
1631 	net = alloc_etherdev(sizeof(*dev));
1632 	if (!net)
1633 		goto out;
1634 
1635 	/* netdev_printk() needs this so do it as early as possible */
1636 	SET_NETDEV_DEV(net, &udev->dev);
1637 
1638 	dev = netdev_priv(net);
1639 	dev->udev = xdev;
1640 	dev->intf = udev;
1641 	dev->driver_info = info;
1642 	dev->driver_name = name;
1643 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1644 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1645 	init_waitqueue_head(&dev->wait);
1646 	skb_queue_head_init (&dev->rxq);
1647 	skb_queue_head_init (&dev->txq);
1648 	skb_queue_head_init (&dev->done);
1649 	skb_queue_head_init(&dev->rxq_pause);
1650 	dev->bh.func = usbnet_bh;
1651 	dev->bh.data = (unsigned long) dev;
1652 	INIT_WORK (&dev->kevent, usbnet_deferred_kevent);
1653 	init_usb_anchor(&dev->deferred);
1654 	dev->delay.function = usbnet_bh;
1655 	dev->delay.data = (unsigned long) dev;
1656 	init_timer (&dev->delay);
1657 	mutex_init (&dev->phy_mutex);
1658 	mutex_init(&dev->interrupt_mutex);
1659 	dev->interrupt_count = 0;
1660 
1661 	dev->net = net;
1662 	strcpy (net->name, "usb%d");
1663 	memcpy (net->dev_addr, node_id, sizeof node_id);
1664 
1665 	/* rx and tx sides can use different message sizes;
1666 	 * bind() should set rx_urb_size in that case.
1667 	 */
1668 	dev->hard_mtu = net->mtu + net->hard_header_len;
1669 
1670 	net->netdev_ops = &usbnet_netdev_ops;
1671 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1672 	net->ethtool_ops = &usbnet_ethtool_ops;
1673 
1674 	// allow device-specific bind/init procedures
1675 	// NOTE net->name still not usable ...
1676 	if (info->bind) {
1677 		status = info->bind (dev, udev);
1678 		if (status < 0)
1679 			goto out1;
1680 
1681 		// heuristic:  "usb%d" for links we know are two-host,
1682 		// else "eth%d" when there's reasonable doubt.  userspace
1683 		// can rename the link if it knows better.
1684 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1685 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1686 		     (net->dev_addr [0] & 0x02) == 0))
1687 			strcpy (net->name, "eth%d");
1688 		/* WLAN devices should always be named "wlan%d" */
1689 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1690 			strcpy(net->name, "wlan%d");
1691 		/* WWAN devices should always be named "wwan%d" */
1692 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1693 			strcpy(net->name, "wwan%d");
1694 
1695 		/* devices that cannot do ARP */
1696 		if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1697 			net->flags |= IFF_NOARP;
1698 
1699 		/* maybe the remote can't receive an Ethernet MTU */
1700 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1701 			net->mtu = dev->hard_mtu - net->hard_header_len;
1702 	} else if (!info->in || !info->out)
1703 		status = usbnet_get_endpoints (dev, udev);
1704 	else {
1705 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1706 		dev->out = usb_sndbulkpipe (xdev, info->out);
1707 		if (!(info->flags & FLAG_NO_SETINT))
1708 			status = usb_set_interface (xdev,
1709 				interface->desc.bInterfaceNumber,
1710 				interface->desc.bAlternateSetting);
1711 		else
1712 			status = 0;
1713 
1714 	}
1715 	if (status >= 0 && dev->status)
1716 		status = init_status (dev, udev);
1717 	if (status < 0)
1718 		goto out3;
1719 
1720 	if (!dev->rx_urb_size)
1721 		dev->rx_urb_size = dev->hard_mtu;
1722 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1723 
1724 	/* let userspace know we have a random address */
1725 	if (ether_addr_equal(net->dev_addr, node_id))
1726 		net->addr_assign_type = NET_ADDR_RANDOM;
1727 
1728 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1729 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1730 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1731 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1732 
1733 	/* initialize max rx_qlen and tx_qlen */
1734 	usbnet_update_max_qlen(dev);
1735 
1736 	if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&
1737 		!(info->flags & FLAG_MULTI_PACKET)) {
1738 		dev->padding_pkt = kzalloc(1, GFP_KERNEL);
1739 		if (!dev->padding_pkt) {
1740 			status = -ENOMEM;
1741 			goto out4;
1742 		}
1743 	}
1744 
1745 	status = register_netdev (net);
1746 	if (status)
1747 		goto out5;
1748 	netif_info(dev, probe, dev->net,
1749 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1750 		   udev->dev.driver->name,
1751 		   xdev->bus->bus_name, xdev->devpath,
1752 		   dev->driver_info->description,
1753 		   net->dev_addr);
1754 
1755 	// ok, it's ready to go.
1756 	usb_set_intfdata (udev, dev);
1757 
1758 	netif_device_attach (net);
1759 
1760 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1761 		usbnet_link_change(dev, 0, 0);
1762 
1763 	return 0;
1764 
1765 out5:
1766 	kfree(dev->padding_pkt);
1767 out4:
1768 	usb_free_urb(dev->interrupt);
1769 out3:
1770 	if (info->unbind)
1771 		info->unbind (dev, udev);
1772 out1:
1773 	/* subdrivers must undo all they did in bind() if they
1774 	 * fail it, but we may fail later and a deferred kevent
1775 	 * may trigger an error resubmitting itself and, worse,
1776 	 * schedule a timer. So we kill it all just in case.
1777 	 */
1778 	cancel_work_sync(&dev->kevent);
1779 	del_timer_sync(&dev->delay);
1780 	free_netdev(net);
1781 out:
1782 	return status;
1783 }
1784 EXPORT_SYMBOL_GPL(usbnet_probe);
1785 
1786 /*-------------------------------------------------------------------------*/
1787 
1788 /*
1789  * suspend the whole driver as soon as the first interface is suspended
1790  * resume only when the last interface is resumed
1791  */
1792 
1793 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1794 {
1795 	struct usbnet		*dev = usb_get_intfdata(intf);
1796 
1797 	if (!dev->suspend_count++) {
1798 		spin_lock_irq(&dev->txq.lock);
1799 		/* don't autosuspend while transmitting */
1800 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1801 			dev->suspend_count--;
1802 			spin_unlock_irq(&dev->txq.lock);
1803 			return -EBUSY;
1804 		} else {
1805 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1806 			spin_unlock_irq(&dev->txq.lock);
1807 		}
1808 		/*
1809 		 * accelerate emptying of the rx and queues, to avoid
1810 		 * having everything error out.
1811 		 */
1812 		netif_device_detach (dev->net);
1813 		usbnet_terminate_urbs(dev);
1814 		__usbnet_status_stop_force(dev);
1815 
1816 		/*
1817 		 * reattach so runtime management can use and
1818 		 * wake the device
1819 		 */
1820 		netif_device_attach (dev->net);
1821 	}
1822 	return 0;
1823 }
1824 EXPORT_SYMBOL_GPL(usbnet_suspend);
1825 
1826 int usbnet_resume (struct usb_interface *intf)
1827 {
1828 	struct usbnet		*dev = usb_get_intfdata(intf);
1829 	struct sk_buff          *skb;
1830 	struct urb              *res;
1831 	int                     retval;
1832 
1833 	if (!--dev->suspend_count) {
1834 		/* resume interrupt URB if it was previously submitted */
1835 		__usbnet_status_start_force(dev, GFP_NOIO);
1836 
1837 		spin_lock_irq(&dev->txq.lock);
1838 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1839 
1840 			skb = (struct sk_buff *)res->context;
1841 			retval = usb_submit_urb(res, GFP_ATOMIC);
1842 			if (retval < 0) {
1843 				dev_kfree_skb_any(skb);
1844 				kfree(res->sg);
1845 				usb_free_urb(res);
1846 				usb_autopm_put_interface_async(dev->intf);
1847 			} else {
1848 				netif_trans_update(dev->net);
1849 				__skb_queue_tail(&dev->txq, skb);
1850 			}
1851 		}
1852 
1853 		smp_mb();
1854 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1855 		spin_unlock_irq(&dev->txq.lock);
1856 
1857 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1858 			/* handle remote wakeup ASAP
1859 			 * we cannot race against stop
1860 			 */
1861 			if (netif_device_present(dev->net) &&
1862 				!timer_pending(&dev->delay) &&
1863 				!test_bit(EVENT_RX_HALT, &dev->flags))
1864 					rx_alloc_submit(dev, GFP_NOIO);
1865 
1866 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1867 				netif_tx_wake_all_queues(dev->net);
1868 			tasklet_schedule (&dev->bh);
1869 		}
1870 	}
1871 
1872 	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1873 		usb_autopm_get_interface_no_resume(intf);
1874 
1875 	return 0;
1876 }
1877 EXPORT_SYMBOL_GPL(usbnet_resume);
1878 
1879 /*
1880  * Either a subdriver implements manage_power, then it is assumed to always
1881  * be ready to be suspended or it reports the readiness to be suspended
1882  * explicitly
1883  */
1884 void usbnet_device_suggests_idle(struct usbnet *dev)
1885 {
1886 	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1887 		dev->intf->needs_remote_wakeup = 1;
1888 		usb_autopm_put_interface_async(dev->intf);
1889 	}
1890 }
1891 EXPORT_SYMBOL(usbnet_device_suggests_idle);
1892 
1893 /*
1894  * For devices that can do without special commands
1895  */
1896 int usbnet_manage_power(struct usbnet *dev, int on)
1897 {
1898 	dev->intf->needs_remote_wakeup = on;
1899 	return 0;
1900 }
1901 EXPORT_SYMBOL(usbnet_manage_power);
1902 
1903 void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
1904 {
1905 	/* update link after link is reseted */
1906 	if (link && !need_reset)
1907 		netif_carrier_on(dev->net);
1908 	else
1909 		netif_carrier_off(dev->net);
1910 
1911 	if (need_reset && link)
1912 		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
1913 	else
1914 		usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
1915 }
1916 EXPORT_SYMBOL(usbnet_link_change);
1917 
1918 /*-------------------------------------------------------------------------*/
1919 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1920 			     u16 value, u16 index, void *data, u16 size)
1921 {
1922 	void *buf = NULL;
1923 	int err = -ENOMEM;
1924 
1925 	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
1926 		   " value=0x%04x index=0x%04x size=%d\n",
1927 		   cmd, reqtype, value, index, size);
1928 
1929 	if (data) {
1930 		buf = kmalloc(size, GFP_KERNEL);
1931 		if (!buf)
1932 			goto out;
1933 	}
1934 
1935 	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
1936 			      cmd, reqtype, value, index, buf, size,
1937 			      USB_CTRL_GET_TIMEOUT);
1938 	if (err > 0 && err <= size)
1939 		memcpy(data, buf, err);
1940 	kfree(buf);
1941 out:
1942 	return err;
1943 }
1944 
1945 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1946 			      u16 value, u16 index, const void *data,
1947 			      u16 size)
1948 {
1949 	void *buf = NULL;
1950 	int err = -ENOMEM;
1951 
1952 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
1953 		   " value=0x%04x index=0x%04x size=%d\n",
1954 		   cmd, reqtype, value, index, size);
1955 
1956 	if (data) {
1957 		buf = kmemdup(data, size, GFP_KERNEL);
1958 		if (!buf)
1959 			goto out;
1960 	}
1961 
1962 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
1963 			      cmd, reqtype, value, index, buf, size,
1964 			      USB_CTRL_SET_TIMEOUT);
1965 	kfree(buf);
1966 
1967 out:
1968 	return err;
1969 }
1970 
1971 int cdc_parse_cdc_header(struct usb_cdc_parsed_header *hdr,
1972 				struct usb_interface *intf,
1973 				u8 *buffer,
1974 				int buflen)
1975 {
1976 	/* duplicates are ignored */
1977 	struct usb_cdc_union_desc *union_header = NULL;
1978 
1979 	/* duplicates are not tolerated */
1980 	struct usb_cdc_header_desc *header = NULL;
1981 	struct usb_cdc_ether_desc *ether = NULL;
1982 	struct usb_cdc_mdlm_detail_desc *detail = NULL;
1983 	struct usb_cdc_mdlm_desc *desc = NULL;
1984 
1985 	unsigned int elength;
1986 	int cnt = 0;
1987 
1988 	memset(hdr, 0x00, sizeof(struct usb_cdc_parsed_header));
1989 	hdr->phonet_magic_present = false;
1990 	while (buflen > 0) {
1991 		elength = buffer[0];
1992 		if (!elength) {
1993 			dev_err(&intf->dev, "skipping garbage byte\n");
1994 			elength = 1;
1995 			goto next_desc;
1996 		}
1997 		if (buffer[1] != USB_DT_CS_INTERFACE) {
1998 			dev_err(&intf->dev, "skipping garbage\n");
1999 			goto next_desc;
2000 		}
2001 
2002 		switch (buffer[2]) {
2003 		case USB_CDC_UNION_TYPE: /* we've found it */
2004 			if (elength < sizeof(struct usb_cdc_union_desc))
2005 				goto next_desc;
2006 			if (union_header) {
2007 				dev_err(&intf->dev, "More than one union descriptor, skipping ...\n");
2008 				goto next_desc;
2009 			}
2010 			union_header = (struct usb_cdc_union_desc *)buffer;
2011 			break;
2012 		case USB_CDC_COUNTRY_TYPE:
2013 			if (elength < sizeof(struct usb_cdc_country_functional_desc))
2014 				goto next_desc;
2015 			hdr->usb_cdc_country_functional_desc =
2016 				(struct usb_cdc_country_functional_desc *)buffer;
2017 			break;
2018 		case USB_CDC_HEADER_TYPE:
2019 			if (elength != sizeof(struct usb_cdc_header_desc))
2020 				goto next_desc;
2021 			if (header)
2022 				return -EINVAL;
2023 			header = (struct usb_cdc_header_desc *)buffer;
2024 			break;
2025 		case USB_CDC_ACM_TYPE:
2026 			if (elength < sizeof(struct usb_cdc_acm_descriptor))
2027 				goto next_desc;
2028 			hdr->usb_cdc_acm_descriptor =
2029 				(struct usb_cdc_acm_descriptor *)buffer;
2030 			break;
2031 		case USB_CDC_ETHERNET_TYPE:
2032 			if (elength != sizeof(struct usb_cdc_ether_desc))
2033 				goto next_desc;
2034 			if (ether)
2035 				return -EINVAL;
2036 			ether = (struct usb_cdc_ether_desc *)buffer;
2037 			break;
2038 		case USB_CDC_CALL_MANAGEMENT_TYPE:
2039 			if (elength < sizeof(struct usb_cdc_call_mgmt_descriptor))
2040 				goto next_desc;
2041 			hdr->usb_cdc_call_mgmt_descriptor =
2042 				(struct usb_cdc_call_mgmt_descriptor *)buffer;
2043 			break;
2044 		case USB_CDC_DMM_TYPE:
2045 			if (elength < sizeof(struct usb_cdc_dmm_desc))
2046 				goto next_desc;
2047 			hdr->usb_cdc_dmm_desc =
2048 				(struct usb_cdc_dmm_desc *)buffer;
2049 			break;
2050 		case USB_CDC_MDLM_TYPE:
2051 			if (elength < sizeof(struct usb_cdc_mdlm_desc *))
2052 				goto next_desc;
2053 			if (desc)
2054 				return -EINVAL;
2055 			desc = (struct usb_cdc_mdlm_desc *)buffer;
2056 			break;
2057 		case USB_CDC_MDLM_DETAIL_TYPE:
2058 			if (elength < sizeof(struct usb_cdc_mdlm_detail_desc *))
2059 				goto next_desc;
2060 			if (detail)
2061 				return -EINVAL;
2062 			detail = (struct usb_cdc_mdlm_detail_desc *)buffer;
2063 			break;
2064 		case USB_CDC_NCM_TYPE:
2065 			if (elength < sizeof(struct usb_cdc_ncm_desc))
2066 				goto next_desc;
2067 			hdr->usb_cdc_ncm_desc = (struct usb_cdc_ncm_desc *)buffer;
2068 			break;
2069 		case USB_CDC_MBIM_TYPE:
2070 			if (elength < sizeof(struct usb_cdc_mbim_desc))
2071 				goto next_desc;
2072 
2073 			hdr->usb_cdc_mbim_desc = (struct usb_cdc_mbim_desc *)buffer;
2074 			break;
2075 		case USB_CDC_MBIM_EXTENDED_TYPE:
2076 			if (elength < sizeof(struct usb_cdc_mbim_extended_desc))
2077 				break;
2078 			hdr->usb_cdc_mbim_extended_desc =
2079 				(struct usb_cdc_mbim_extended_desc *)buffer;
2080 			break;
2081 		case CDC_PHONET_MAGIC_NUMBER:
2082 			hdr->phonet_magic_present = true;
2083 			break;
2084 		default:
2085 			/*
2086 			 * there are LOTS more CDC descriptors that
2087 			 * could legitimately be found here.
2088 			 */
2089 			dev_dbg(&intf->dev, "Ignoring descriptor: type %02x, length %ud\n",
2090 					buffer[2], elength);
2091 			goto next_desc;
2092 		}
2093 		cnt++;
2094 next_desc:
2095 		buflen -= elength;
2096 		buffer += elength;
2097 	}
2098 	hdr->usb_cdc_union_desc = union_header;
2099 	hdr->usb_cdc_header_desc = header;
2100 	hdr->usb_cdc_mdlm_detail_desc = detail;
2101 	hdr->usb_cdc_mdlm_desc = desc;
2102 	hdr->usb_cdc_ether_desc = ether;
2103 	return cnt;
2104 }
2105 
2106 EXPORT_SYMBOL(cdc_parse_cdc_header);
2107 
2108 /*
2109  * The function can't be called inside suspend/resume callback,
2110  * otherwise deadlock will be caused.
2111  */
2112 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2113 		    u16 value, u16 index, void *data, u16 size)
2114 {
2115 	int ret;
2116 
2117 	if (usb_autopm_get_interface(dev->intf) < 0)
2118 		return -ENODEV;
2119 	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2120 				data, size);
2121 	usb_autopm_put_interface(dev->intf);
2122 	return ret;
2123 }
2124 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
2125 
2126 /*
2127  * The function can't be called inside suspend/resume callback,
2128  * otherwise deadlock will be caused.
2129  */
2130 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2131 		     u16 value, u16 index, const void *data, u16 size)
2132 {
2133 	int ret;
2134 
2135 	if (usb_autopm_get_interface(dev->intf) < 0)
2136 		return -ENODEV;
2137 	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2138 				 data, size);
2139 	usb_autopm_put_interface(dev->intf);
2140 	return ret;
2141 }
2142 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
2143 
2144 /*
2145  * The function can be called inside suspend/resume callback safely
2146  * and should only be called by suspend/resume callback generally.
2147  */
2148 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2149 			  u16 value, u16 index, void *data, u16 size)
2150 {
2151 	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2152 				 data, size);
2153 }
2154 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
2155 
2156 /*
2157  * The function can be called inside suspend/resume callback safely
2158  * and should only be called by suspend/resume callback generally.
2159  */
2160 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2161 			  u16 value, u16 index, const void *data,
2162 			  u16 size)
2163 {
2164 	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2165 				  data, size);
2166 }
2167 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
2168 
2169 static void usbnet_async_cmd_cb(struct urb *urb)
2170 {
2171 	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
2172 	int status = urb->status;
2173 
2174 	if (status < 0)
2175 		dev_dbg(&urb->dev->dev, "%s failed with %d",
2176 			__func__, status);
2177 
2178 	kfree(req);
2179 	usb_free_urb(urb);
2180 }
2181 
2182 /*
2183  * The caller must make sure that device can't be put into suspend
2184  * state until the control URB completes.
2185  */
2186 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
2187 			   u16 value, u16 index, const void *data, u16 size)
2188 {
2189 	struct usb_ctrlrequest *req = NULL;
2190 	struct urb *urb;
2191 	int err = -ENOMEM;
2192 	void *buf = NULL;
2193 
2194 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2195 		   " value=0x%04x index=0x%04x size=%d\n",
2196 		   cmd, reqtype, value, index, size);
2197 
2198 	urb = usb_alloc_urb(0, GFP_ATOMIC);
2199 	if (!urb) {
2200 		netdev_err(dev->net, "Error allocating URB in"
2201 			   " %s!\n", __func__);
2202 		goto fail;
2203 	}
2204 
2205 	if (data) {
2206 		buf = kmemdup(data, size, GFP_ATOMIC);
2207 		if (!buf) {
2208 			netdev_err(dev->net, "Error allocating buffer"
2209 				   " in %s!\n", __func__);
2210 			goto fail_free;
2211 		}
2212 	}
2213 
2214 	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
2215 	if (!req)
2216 		goto fail_free_buf;
2217 
2218 	req->bRequestType = reqtype;
2219 	req->bRequest = cmd;
2220 	req->wValue = cpu_to_le16(value);
2221 	req->wIndex = cpu_to_le16(index);
2222 	req->wLength = cpu_to_le16(size);
2223 
2224 	usb_fill_control_urb(urb, dev->udev,
2225 			     usb_sndctrlpipe(dev->udev, 0),
2226 			     (void *)req, buf, size,
2227 			     usbnet_async_cmd_cb, req);
2228 	urb->transfer_flags |= URB_FREE_BUFFER;
2229 
2230 	err = usb_submit_urb(urb, GFP_ATOMIC);
2231 	if (err < 0) {
2232 		netdev_err(dev->net, "Error submitting the control"
2233 			   " message: status=%d\n", err);
2234 		goto fail_free;
2235 	}
2236 	return 0;
2237 
2238 fail_free_buf:
2239 	kfree(buf);
2240 fail_free:
2241 	kfree(req);
2242 	usb_free_urb(urb);
2243 fail:
2244 	return err;
2245 
2246 }
2247 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
2248 /*-------------------------------------------------------------------------*/
2249 
2250 static int __init usbnet_init(void)
2251 {
2252 	/* Compiler should optimize this out. */
2253 	BUILD_BUG_ON(
2254 		FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
2255 
2256 	eth_random_addr(node_id);
2257 	return 0;
2258 }
2259 module_init(usbnet_init);
2260 
2261 static void __exit usbnet_exit(void)
2262 {
2263 }
2264 module_exit(usbnet_exit);
2265 
2266 MODULE_AUTHOR("David Brownell");
2267 MODULE_DESCRIPTION("USB network driver framework");
2268 MODULE_LICENSE("GPL");
2269