xref: /openbmc/linux/drivers/net/usb/usbnet.c (revision a88c32ae15f25fcf0a3c9fadd92f840a1abf0e43)
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, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19  */
20 
21 /*
22  * This is a generic "USB networking" framework that works with several
23  * kinds of full and high speed networking devices:  host-to-host cables,
24  * smart usb peripherals, and actual Ethernet adapters.
25  *
26  * These devices usually differ in terms of control protocols (if they
27  * even have one!) and sometimes they define new framing to wrap or batch
28  * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
29  * so interface (un)binding, endpoint I/O queues, fault handling, and other
30  * issues can usefully be addressed by this framework.
31  */
32 
33 // #define	DEBUG			// error path messages, extra info
34 // #define	VERBOSE			// more; success messages
35 
36 #include <linux/module.h>
37 #include <linux/init.h>
38 #include <linux/netdevice.h>
39 #include <linux/etherdevice.h>
40 #include <linux/ctype.h>
41 #include <linux/ethtool.h>
42 #include <linux/workqueue.h>
43 #include <linux/mii.h>
44 #include <linux/usb.h>
45 #include <linux/usb/usbnet.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 khubd might disconnect()
74 // us (it polls at HZ/4 usually) before we report too many false errors.
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, i;
164 	unsigned char	buf [13];
165 
166 	tmp = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
167 	if (tmp != 12) {
168 		dev_dbg(&dev->udev->dev,
169 			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
170 		if (tmp >= 0)
171 			tmp = -EINVAL;
172 		return tmp;
173 	}
174 	for (i = tmp = 0; i < 6; i++, tmp += 2)
175 		dev->net->dev_addr [i] =
176 			(hex_to_bin(buf[tmp]) << 4) + hex_to_bin(buf[tmp + 1]);
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 	if (!netif_running (dev->net))
208 		return;
209 
210 	status = usb_submit_urb (urb, GFP_ATOMIC);
211 	if (status != 0)
212 		netif_err(dev, timer, dev->net,
213 			  "intr resubmit --> %d\n", status);
214 }
215 
216 static int init_status (struct usbnet *dev, struct usb_interface *intf)
217 {
218 	char		*buf = NULL;
219 	unsigned	pipe = 0;
220 	unsigned	maxp;
221 	unsigned	period;
222 
223 	if (!dev->driver_info->status)
224 		return 0;
225 
226 	pipe = usb_rcvintpipe (dev->udev,
227 			dev->status->desc.bEndpointAddress
228 				& USB_ENDPOINT_NUMBER_MASK);
229 	maxp = usb_maxpacket (dev->udev, pipe, 0);
230 
231 	/* avoid 1 msec chatter:  min 8 msec poll rate */
232 	period = max ((int) dev->status->desc.bInterval,
233 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
234 
235 	buf = kmalloc (maxp, GFP_KERNEL);
236 	if (buf) {
237 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
238 		if (!dev->interrupt) {
239 			kfree (buf);
240 			return -ENOMEM;
241 		} else {
242 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
243 				buf, maxp, intr_complete, dev, period);
244 			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
245 			dev_dbg(&intf->dev,
246 				"status ep%din, %d bytes period %d\n",
247 				usb_pipeendpoint(pipe), maxp, period);
248 		}
249 	}
250 	return 0;
251 }
252 
253 /* Submit the interrupt URB if not previously submitted, increasing refcount */
254 int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
255 {
256 	int ret = 0;
257 
258 	WARN_ON_ONCE(dev->interrupt == NULL);
259 	if (dev->interrupt) {
260 		mutex_lock(&dev->interrupt_mutex);
261 
262 		if (++dev->interrupt_count == 1)
263 			ret = usb_submit_urb(dev->interrupt, mem_flags);
264 
265 		dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
266 			dev->interrupt_count);
267 		mutex_unlock(&dev->interrupt_mutex);
268 	}
269 	return ret;
270 }
271 EXPORT_SYMBOL_GPL(usbnet_status_start);
272 
273 /* For resume; submit interrupt URB if previously submitted */
274 static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
275 {
276 	int ret = 0;
277 
278 	mutex_lock(&dev->interrupt_mutex);
279 	if (dev->interrupt_count) {
280 		ret = usb_submit_urb(dev->interrupt, mem_flags);
281 		dev_dbg(&dev->udev->dev,
282 			"submitted interrupt URB for resume\n");
283 	}
284 	mutex_unlock(&dev->interrupt_mutex);
285 	return ret;
286 }
287 
288 /* Kill the interrupt URB if all submitters want it killed */
289 void usbnet_status_stop(struct usbnet *dev)
290 {
291 	if (dev->interrupt) {
292 		mutex_lock(&dev->interrupt_mutex);
293 		WARN_ON(dev->interrupt_count == 0);
294 
295 		if (dev->interrupt_count && --dev->interrupt_count == 0)
296 			usb_kill_urb(dev->interrupt);
297 
298 		dev_dbg(&dev->udev->dev,
299 			"decremented interrupt URB count to %d\n",
300 			dev->interrupt_count);
301 		mutex_unlock(&dev->interrupt_mutex);
302 	}
303 }
304 EXPORT_SYMBOL_GPL(usbnet_status_stop);
305 
306 /* For suspend; always kill interrupt URB */
307 static void __usbnet_status_stop_force(struct usbnet *dev)
308 {
309 	if (dev->interrupt) {
310 		mutex_lock(&dev->interrupt_mutex);
311 		usb_kill_urb(dev->interrupt);
312 		dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
313 		mutex_unlock(&dev->interrupt_mutex);
314 	}
315 }
316 
317 /* Passes this packet up the stack, updating its accounting.
318  * Some link protocols batch packets, so their rx_fixup paths
319  * can return clones as well as just modify the original skb.
320  */
321 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
322 {
323 	int	status;
324 
325 	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
326 		skb_queue_tail(&dev->rxq_pause, skb);
327 		return;
328 	}
329 
330 	skb->protocol = eth_type_trans (skb, dev->net);
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 	default:
359 		dev->rx_qlen = dev->tx_qlen = 4;
360 	}
361 }
362 EXPORT_SYMBOL_GPL(usbnet_update_max_qlen);
363 
364 
365 /*-------------------------------------------------------------------------
366  *
367  * Network Device Driver (peer link to "Host Device", from USB host)
368  *
369  *-------------------------------------------------------------------------*/
370 
371 int usbnet_change_mtu (struct net_device *net, int new_mtu)
372 {
373 	struct usbnet	*dev = netdev_priv(net);
374 	int		ll_mtu = new_mtu + net->hard_header_len;
375 	int		old_hard_mtu = dev->hard_mtu;
376 	int		old_rx_urb_size = dev->rx_urb_size;
377 
378 	if (new_mtu <= 0)
379 		return -EINVAL;
380 	// no second zero-length packet read wanted after mtu-sized packets
381 	if ((ll_mtu % dev->maxpacket) == 0)
382 		return -EDOM;
383 	net->mtu = new_mtu;
384 
385 	dev->hard_mtu = net->mtu + net->hard_header_len;
386 	if (dev->rx_urb_size == old_hard_mtu) {
387 		dev->rx_urb_size = dev->hard_mtu;
388 		if (dev->rx_urb_size > old_rx_urb_size)
389 			usbnet_unlink_rx_urbs(dev);
390 	}
391 
392 	/* max qlen depend on hard_mtu and rx_urb_size */
393 	usbnet_update_max_qlen(dev);
394 
395 	return 0;
396 }
397 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
398 
399 /* The caller must hold list->lock */
400 static void __usbnet_queue_skb(struct sk_buff_head *list,
401 			struct sk_buff *newsk, enum skb_state state)
402 {
403 	struct skb_data *entry = (struct skb_data *) newsk->cb;
404 
405 	__skb_queue_tail(list, newsk);
406 	entry->state = state;
407 }
408 
409 /*-------------------------------------------------------------------------*/
410 
411 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
412  * completion callbacks.  2.5 should have fixed those bugs...
413  */
414 
415 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
416 		struct sk_buff_head *list, enum skb_state state)
417 {
418 	unsigned long		flags;
419 	enum skb_state 		old_state;
420 	struct skb_data *entry = (struct skb_data *) skb->cb;
421 
422 	spin_lock_irqsave(&list->lock, flags);
423 	old_state = entry->state;
424 	entry->state = state;
425 	__skb_unlink(skb, list);
426 	spin_unlock(&list->lock);
427 	spin_lock(&dev->done.lock);
428 	__skb_queue_tail(&dev->done, skb);
429 	if (dev->done.qlen == 1)
430 		tasklet_schedule(&dev->bh);
431 	spin_unlock_irqrestore(&dev->done.lock, flags);
432 	return old_state;
433 }
434 
435 /* some work can't be done in tasklets, so we use keventd
436  *
437  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
438  * but tasklet_schedule() doesn't.  hope the failure is rare.
439  */
440 void usbnet_defer_kevent (struct usbnet *dev, int work)
441 {
442 	set_bit (work, &dev->flags);
443 	if (!schedule_work (&dev->kevent)) {
444 		if (net_ratelimit())
445 			netdev_err(dev->net, "kevent %d may have been dropped\n", work);
446 	} else {
447 		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
448 	}
449 }
450 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
451 
452 /*-------------------------------------------------------------------------*/
453 
454 static void rx_complete (struct urb *urb);
455 
456 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
457 {
458 	struct sk_buff		*skb;
459 	struct skb_data		*entry;
460 	int			retval = 0;
461 	unsigned long		lockflags;
462 	size_t			size = dev->rx_urb_size;
463 
464 	/* prevent rx skb allocation when error ratio is high */
465 	if (test_bit(EVENT_RX_KILL, &dev->flags)) {
466 		usb_free_urb(urb);
467 		return -ENOLINK;
468 	}
469 
470 	skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
471 	if (!skb) {
472 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
473 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
474 		usb_free_urb (urb);
475 		return -ENOMEM;
476 	}
477 
478 	entry = (struct skb_data *) skb->cb;
479 	entry->urb = urb;
480 	entry->dev = dev;
481 	entry->length = 0;
482 
483 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
484 		skb->data, size, rx_complete, skb);
485 
486 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
487 
488 	if (netif_running (dev->net) &&
489 	    netif_device_present (dev->net) &&
490 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
491 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
492 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
493 		case -EPIPE:
494 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
495 			break;
496 		case -ENOMEM:
497 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
498 			break;
499 		case -ENODEV:
500 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
501 			netif_device_detach (dev->net);
502 			break;
503 		case -EHOSTUNREACH:
504 			retval = -ENOLINK;
505 			break;
506 		default:
507 			netif_dbg(dev, rx_err, dev->net,
508 				  "rx submit, %d\n", retval);
509 			tasklet_schedule (&dev->bh);
510 			break;
511 		case 0:
512 			__usbnet_queue_skb(&dev->rxq, skb, rx_start);
513 		}
514 	} else {
515 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
516 		retval = -ENOLINK;
517 	}
518 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
519 	if (retval) {
520 		dev_kfree_skb_any (skb);
521 		usb_free_urb (urb);
522 	}
523 	return retval;
524 }
525 
526 
527 /*-------------------------------------------------------------------------*/
528 
529 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
530 {
531 	if (dev->driver_info->rx_fixup &&
532 	    !dev->driver_info->rx_fixup (dev, skb)) {
533 		/* With RX_ASSEMBLE, rx_fixup() must update counters */
534 		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
535 			dev->net->stats.rx_errors++;
536 		goto done;
537 	}
538 	// else network stack removes extra byte if we forced a short packet
539 
540 	if (skb->len) {
541 		/* all data was already cloned from skb inside the driver */
542 		if (dev->driver_info->flags & FLAG_MULTI_PACKET)
543 			dev_kfree_skb_any(skb);
544 		else
545 			usbnet_skb_return(dev, skb);
546 		return;
547 	}
548 
549 	netif_dbg(dev, rx_err, dev->net, "drop\n");
550 	dev->net->stats.rx_errors++;
551 done:
552 	skb_queue_tail(&dev->done, skb);
553 }
554 
555 /*-------------------------------------------------------------------------*/
556 
557 static void rx_complete (struct urb *urb)
558 {
559 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
560 	struct skb_data		*entry = (struct skb_data *) skb->cb;
561 	struct usbnet		*dev = entry->dev;
562 	int			urb_status = urb->status;
563 	enum skb_state		state;
564 
565 	skb_put (skb, urb->actual_length);
566 	state = rx_done;
567 	entry->urb = NULL;
568 
569 	switch (urb_status) {
570 	/* success */
571 	case 0:
572 		if (skb->len < dev->net->hard_header_len) {
573 			state = rx_cleanup;
574 			dev->net->stats.rx_errors++;
575 			dev->net->stats.rx_length_errors++;
576 			netif_dbg(dev, rx_err, dev->net,
577 				  "rx length %d\n", skb->len);
578 		}
579 		break;
580 
581 	/* stalls need manual reset. this is rare ... except that
582 	 * when going through USB 2.0 TTs, unplug appears this way.
583 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
584 	 * storm, recovering as needed.
585 	 */
586 	case -EPIPE:
587 		dev->net->stats.rx_errors++;
588 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
589 		// FALLTHROUGH
590 
591 	/* software-driven interface shutdown */
592 	case -ECONNRESET:		/* async unlink */
593 	case -ESHUTDOWN:		/* hardware gone */
594 		netif_dbg(dev, ifdown, dev->net,
595 			  "rx shutdown, code %d\n", urb_status);
596 		goto block;
597 
598 	/* we get controller i/o faults during khubd disconnect() delays.
599 	 * throttle down resubmits, to avoid log floods; just temporarily,
600 	 * so we still recover when the fault isn't a khubd delay.
601 	 */
602 	case -EPROTO:
603 	case -ETIME:
604 	case -EILSEQ:
605 		dev->net->stats.rx_errors++;
606 		if (!timer_pending (&dev->delay)) {
607 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
608 			netif_dbg(dev, link, dev->net,
609 				  "rx throttle %d\n", urb_status);
610 		}
611 block:
612 		state = rx_cleanup;
613 		entry->urb = urb;
614 		urb = NULL;
615 		break;
616 
617 	/* data overrun ... flush fifo? */
618 	case -EOVERFLOW:
619 		dev->net->stats.rx_over_errors++;
620 		// FALLTHROUGH
621 
622 	default:
623 		state = rx_cleanup;
624 		dev->net->stats.rx_errors++;
625 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
626 		break;
627 	}
628 
629 	/* stop rx if packet error rate is high */
630 	if (++dev->pkt_cnt > 30) {
631 		dev->pkt_cnt = 0;
632 		dev->pkt_err = 0;
633 	} else {
634 		if (state == rx_cleanup)
635 			dev->pkt_err++;
636 		if (dev->pkt_err > 20)
637 			set_bit(EVENT_RX_KILL, &dev->flags);
638 	}
639 
640 	state = defer_bh(dev, skb, &dev->rxq, state);
641 
642 	if (urb) {
643 		if (netif_running (dev->net) &&
644 		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
645 		    state != unlink_start) {
646 			rx_submit (dev, urb, GFP_ATOMIC);
647 			usb_mark_last_busy(dev->udev);
648 			return;
649 		}
650 		usb_free_urb (urb);
651 	}
652 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
653 }
654 
655 /*-------------------------------------------------------------------------*/
656 void usbnet_pause_rx(struct usbnet *dev)
657 {
658 	set_bit(EVENT_RX_PAUSED, &dev->flags);
659 
660 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
661 }
662 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
663 
664 void usbnet_resume_rx(struct usbnet *dev)
665 {
666 	struct sk_buff *skb;
667 	int num = 0;
668 
669 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
670 
671 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
672 		usbnet_skb_return(dev, skb);
673 		num++;
674 	}
675 
676 	tasklet_schedule(&dev->bh);
677 
678 	netif_dbg(dev, rx_status, dev->net,
679 		  "paused rx queue disabled, %d skbs requeued\n", num);
680 }
681 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
682 
683 void usbnet_purge_paused_rxq(struct usbnet *dev)
684 {
685 	skb_queue_purge(&dev->rxq_pause);
686 }
687 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
688 
689 /*-------------------------------------------------------------------------*/
690 
691 // unlink pending rx/tx; completion handlers do all other cleanup
692 
693 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
694 {
695 	unsigned long		flags;
696 	struct sk_buff		*skb;
697 	int			count = 0;
698 
699 	spin_lock_irqsave (&q->lock, flags);
700 	while (!skb_queue_empty(q)) {
701 		struct skb_data		*entry;
702 		struct urb		*urb;
703 		int			retval;
704 
705 		skb_queue_walk(q, skb) {
706 			entry = (struct skb_data *) skb->cb;
707 			if (entry->state != unlink_start)
708 				goto found;
709 		}
710 		break;
711 found:
712 		entry->state = unlink_start;
713 		urb = entry->urb;
714 
715 		/*
716 		 * Get reference count of the URB to avoid it to be
717 		 * freed during usb_unlink_urb, which may trigger
718 		 * use-after-free problem inside usb_unlink_urb since
719 		 * usb_unlink_urb is always racing with .complete
720 		 * handler(include defer_bh).
721 		 */
722 		usb_get_urb(urb);
723 		spin_unlock_irqrestore(&q->lock, flags);
724 		// during some PM-driven resume scenarios,
725 		// these (async) unlinks complete immediately
726 		retval = usb_unlink_urb (urb);
727 		if (retval != -EINPROGRESS && retval != 0)
728 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
729 		else
730 			count++;
731 		usb_put_urb(urb);
732 		spin_lock_irqsave(&q->lock, flags);
733 	}
734 	spin_unlock_irqrestore (&q->lock, flags);
735 	return count;
736 }
737 
738 // Flush all pending rx urbs
739 // minidrivers may need to do this when the MTU changes
740 
741 void usbnet_unlink_rx_urbs(struct usbnet *dev)
742 {
743 	if (netif_running(dev->net)) {
744 		(void) unlink_urbs (dev, &dev->rxq);
745 		tasklet_schedule(&dev->bh);
746 	}
747 }
748 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
749 
750 /*-------------------------------------------------------------------------*/
751 
752 // precondition: never called in_interrupt
753 static void usbnet_terminate_urbs(struct usbnet *dev)
754 {
755 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
756 	DECLARE_WAITQUEUE(wait, current);
757 	int temp;
758 
759 	/* ensure there are no more active urbs */
760 	add_wait_queue(&unlink_wakeup, &wait);
761 	set_current_state(TASK_UNINTERRUPTIBLE);
762 	dev->wait = &unlink_wakeup;
763 	temp = unlink_urbs(dev, &dev->txq) +
764 		unlink_urbs(dev, &dev->rxq);
765 
766 	/* maybe wait for deletions to finish. */
767 	while (!skb_queue_empty(&dev->rxq)
768 		&& !skb_queue_empty(&dev->txq)
769 		&& !skb_queue_empty(&dev->done)) {
770 			schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
771 			set_current_state(TASK_UNINTERRUPTIBLE);
772 			netif_dbg(dev, ifdown, dev->net,
773 				  "waited for %d urb completions\n", temp);
774 	}
775 	set_current_state(TASK_RUNNING);
776 	dev->wait = NULL;
777 	remove_wait_queue(&unlink_wakeup, &wait);
778 }
779 
780 int usbnet_stop (struct net_device *net)
781 {
782 	struct usbnet		*dev = netdev_priv(net);
783 	struct driver_info	*info = dev->driver_info;
784 	int			retval;
785 
786 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
787 	netif_stop_queue (net);
788 
789 	netif_info(dev, ifdown, dev->net,
790 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
791 		   net->stats.rx_packets, net->stats.tx_packets,
792 		   net->stats.rx_errors, net->stats.tx_errors);
793 
794 	/* allow minidriver to stop correctly (wireless devices to turn off
795 	 * radio etc) */
796 	if (info->stop) {
797 		retval = info->stop(dev);
798 		if (retval < 0)
799 			netif_info(dev, ifdown, dev->net,
800 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
801 				   retval,
802 				   dev->udev->bus->bus_name, dev->udev->devpath,
803 				   info->description);
804 	}
805 
806 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
807 		usbnet_terminate_urbs(dev);
808 
809 	usbnet_status_stop(dev);
810 
811 	usbnet_purge_paused_rxq(dev);
812 
813 	/* deferred work (task, timer, softirq) must also stop.
814 	 * can't flush_scheduled_work() until we drop rtnl (later),
815 	 * else workers could deadlock; so make workers a NOP.
816 	 */
817 	dev->flags = 0;
818 	del_timer_sync (&dev->delay);
819 	tasklet_kill (&dev->bh);
820 	if (info->manage_power &&
821 	    !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags))
822 		info->manage_power(dev, 0);
823 	else
824 		usb_autopm_put_interface(dev->intf);
825 
826 	return 0;
827 }
828 EXPORT_SYMBOL_GPL(usbnet_stop);
829 
830 /*-------------------------------------------------------------------------*/
831 
832 // posts reads, and enables write queuing
833 
834 // precondition: never called in_interrupt
835 
836 int usbnet_open (struct net_device *net)
837 {
838 	struct usbnet		*dev = netdev_priv(net);
839 	int			retval;
840 	struct driver_info	*info = dev->driver_info;
841 
842 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
843 		netif_info(dev, ifup, dev->net,
844 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
845 			   retval,
846 			   dev->udev->bus->bus_name,
847 			   dev->udev->devpath,
848 			   info->description);
849 		goto done_nopm;
850 	}
851 
852 	// put into "known safe" state
853 	if (info->reset && (retval = info->reset (dev)) < 0) {
854 		netif_info(dev, ifup, dev->net,
855 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
856 			   retval,
857 			   dev->udev->bus->bus_name,
858 			   dev->udev->devpath,
859 			   info->description);
860 		goto done;
861 	}
862 
863 	/* hard_mtu or rx_urb_size may change in reset() */
864 	usbnet_update_max_qlen(dev);
865 
866 	// insist peer be connected
867 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
868 		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
869 		goto done;
870 	}
871 
872 	/* start any status interrupt transfer */
873 	if (dev->interrupt) {
874 		retval = usbnet_status_start(dev, GFP_KERNEL);
875 		if (retval < 0) {
876 			netif_err(dev, ifup, dev->net,
877 				  "intr submit %d\n", retval);
878 			goto done;
879 		}
880 	}
881 
882 	set_bit(EVENT_DEV_OPEN, &dev->flags);
883 	netif_start_queue (net);
884 	netif_info(dev, ifup, dev->net,
885 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
886 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
887 		   dev->net->mtu,
888 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
889 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
890 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
891 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
892 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
893 		   "simple");
894 
895 	/* reset rx error state */
896 	dev->pkt_cnt = 0;
897 	dev->pkt_err = 0;
898 	clear_bit(EVENT_RX_KILL, &dev->flags);
899 
900 	// delay posting reads until we're fully open
901 	tasklet_schedule (&dev->bh);
902 	if (info->manage_power) {
903 		retval = info->manage_power(dev, 1);
904 		if (retval < 0) {
905 			retval = 0;
906 			set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
907 		} else {
908 			usb_autopm_put_interface(dev->intf);
909 		}
910 	}
911 	return retval;
912 done:
913 	usb_autopm_put_interface(dev->intf);
914 done_nopm:
915 	return retval;
916 }
917 EXPORT_SYMBOL_GPL(usbnet_open);
918 
919 /*-------------------------------------------------------------------------*/
920 
921 /* ethtool methods; minidrivers may need to add some more, but
922  * they'll probably want to use this base set.
923  */
924 
925 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
926 {
927 	struct usbnet *dev = netdev_priv(net);
928 
929 	if (!dev->mii.mdio_read)
930 		return -EOPNOTSUPP;
931 
932 	return mii_ethtool_gset(&dev->mii, cmd);
933 }
934 EXPORT_SYMBOL_GPL(usbnet_get_settings);
935 
936 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
937 {
938 	struct usbnet *dev = netdev_priv(net);
939 	int retval;
940 
941 	if (!dev->mii.mdio_write)
942 		return -EOPNOTSUPP;
943 
944 	retval = mii_ethtool_sset(&dev->mii, cmd);
945 
946 	/* link speed/duplex might have changed */
947 	if (dev->driver_info->link_reset)
948 		dev->driver_info->link_reset(dev);
949 
950 	/* hard_mtu or rx_urb_size may change in link_reset() */
951 	usbnet_update_max_qlen(dev);
952 
953 	return retval;
954 
955 }
956 EXPORT_SYMBOL_GPL(usbnet_set_settings);
957 
958 u32 usbnet_get_link (struct net_device *net)
959 {
960 	struct usbnet *dev = netdev_priv(net);
961 
962 	/* If a check_connect is defined, return its result */
963 	if (dev->driver_info->check_connect)
964 		return dev->driver_info->check_connect (dev) == 0;
965 
966 	/* if the device has mii operations, use those */
967 	if (dev->mii.mdio_read)
968 		return mii_link_ok(&dev->mii);
969 
970 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
971 	return ethtool_op_get_link(net);
972 }
973 EXPORT_SYMBOL_GPL(usbnet_get_link);
974 
975 int usbnet_nway_reset(struct net_device *net)
976 {
977 	struct usbnet *dev = netdev_priv(net);
978 
979 	if (!dev->mii.mdio_write)
980 		return -EOPNOTSUPP;
981 
982 	return mii_nway_restart(&dev->mii);
983 }
984 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
985 
986 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
987 {
988 	struct usbnet *dev = netdev_priv(net);
989 
990 	strlcpy (info->driver, dev->driver_name, sizeof info->driver);
991 	strlcpy (info->version, DRIVER_VERSION, sizeof info->version);
992 	strlcpy (info->fw_version, dev->driver_info->description,
993 		sizeof info->fw_version);
994 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
995 }
996 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
997 
998 u32 usbnet_get_msglevel (struct net_device *net)
999 {
1000 	struct usbnet *dev = netdev_priv(net);
1001 
1002 	return dev->msg_enable;
1003 }
1004 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
1005 
1006 void usbnet_set_msglevel (struct net_device *net, u32 level)
1007 {
1008 	struct usbnet *dev = netdev_priv(net);
1009 
1010 	dev->msg_enable = level;
1011 }
1012 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
1013 
1014 /* drivers may override default ethtool_ops in their bind() routine */
1015 static const struct ethtool_ops usbnet_ethtool_ops = {
1016 	.get_settings		= usbnet_get_settings,
1017 	.set_settings		= usbnet_set_settings,
1018 	.get_link		= usbnet_get_link,
1019 	.nway_reset		= usbnet_nway_reset,
1020 	.get_drvinfo		= usbnet_get_drvinfo,
1021 	.get_msglevel		= usbnet_get_msglevel,
1022 	.set_msglevel		= usbnet_set_msglevel,
1023 	.get_ts_info		= ethtool_op_get_ts_info,
1024 };
1025 
1026 /*-------------------------------------------------------------------------*/
1027 
1028 static void __handle_link_change(struct usbnet *dev)
1029 {
1030 	if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
1031 		return;
1032 
1033 	if (!netif_carrier_ok(dev->net)) {
1034 		/* kill URBs for reading packets to save bus bandwidth */
1035 		unlink_urbs(dev, &dev->rxq);
1036 
1037 		/*
1038 		 * tx_timeout will unlink URBs for sending packets and
1039 		 * tx queue is stopped by netcore after link becomes off
1040 		 */
1041 	} else {
1042 		/* submitting URBs for reading packets */
1043 		tasklet_schedule(&dev->bh);
1044 	}
1045 
1046 	/* hard_mtu or rx_urb_size may change during link change */
1047 	usbnet_update_max_qlen(dev);
1048 
1049 	clear_bit(EVENT_LINK_CHANGE, &dev->flags);
1050 }
1051 
1052 /* work that cannot be done in interrupt context uses keventd.
1053  *
1054  * NOTE:  with 2.5 we could do more of this using completion callbacks,
1055  * especially now that control transfers can be queued.
1056  */
1057 static void
1058 kevent (struct work_struct *work)
1059 {
1060 	struct usbnet		*dev =
1061 		container_of(work, struct usbnet, kevent);
1062 	int			status;
1063 
1064 	/* usb_clear_halt() needs a thread context */
1065 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
1066 		unlink_urbs (dev, &dev->txq);
1067 		status = usb_autopm_get_interface(dev->intf);
1068 		if (status < 0)
1069 			goto fail_pipe;
1070 		status = usb_clear_halt (dev->udev, dev->out);
1071 		usb_autopm_put_interface(dev->intf);
1072 		if (status < 0 &&
1073 		    status != -EPIPE &&
1074 		    status != -ESHUTDOWN) {
1075 			if (netif_msg_tx_err (dev))
1076 fail_pipe:
1077 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
1078 					   status);
1079 		} else {
1080 			clear_bit (EVENT_TX_HALT, &dev->flags);
1081 			if (status != -ESHUTDOWN)
1082 				netif_wake_queue (dev->net);
1083 		}
1084 	}
1085 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
1086 		unlink_urbs (dev, &dev->rxq);
1087 		status = usb_autopm_get_interface(dev->intf);
1088 		if (status < 0)
1089 			goto fail_halt;
1090 		status = usb_clear_halt (dev->udev, dev->in);
1091 		usb_autopm_put_interface(dev->intf);
1092 		if (status < 0 &&
1093 		    status != -EPIPE &&
1094 		    status != -ESHUTDOWN) {
1095 			if (netif_msg_rx_err (dev))
1096 fail_halt:
1097 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
1098 					   status);
1099 		} else {
1100 			clear_bit (EVENT_RX_HALT, &dev->flags);
1101 			tasklet_schedule (&dev->bh);
1102 		}
1103 	}
1104 
1105 	/* tasklet could resubmit itself forever if memory is tight */
1106 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
1107 		struct urb	*urb = NULL;
1108 		int resched = 1;
1109 
1110 		if (netif_running (dev->net))
1111 			urb = usb_alloc_urb (0, GFP_KERNEL);
1112 		else
1113 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1114 		if (urb != NULL) {
1115 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1116 			status = usb_autopm_get_interface(dev->intf);
1117 			if (status < 0) {
1118 				usb_free_urb(urb);
1119 				goto fail_lowmem;
1120 			}
1121 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
1122 				resched = 0;
1123 			usb_autopm_put_interface(dev->intf);
1124 fail_lowmem:
1125 			if (resched)
1126 				tasklet_schedule (&dev->bh);
1127 		}
1128 	}
1129 
1130 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
1131 		struct driver_info	*info = dev->driver_info;
1132 		int			retval = 0;
1133 
1134 		clear_bit (EVENT_LINK_RESET, &dev->flags);
1135 		status = usb_autopm_get_interface(dev->intf);
1136 		if (status < 0)
1137 			goto skip_reset;
1138 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1139 			usb_autopm_put_interface(dev->intf);
1140 skip_reset:
1141 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1142 				    retval,
1143 				    dev->udev->bus->bus_name,
1144 				    dev->udev->devpath,
1145 				    info->description);
1146 		} else {
1147 			usb_autopm_put_interface(dev->intf);
1148 		}
1149 
1150 		/* handle link change from link resetting */
1151 		__handle_link_change(dev);
1152 	}
1153 
1154 	if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
1155 		__handle_link_change(dev);
1156 
1157 	if (dev->flags)
1158 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1159 }
1160 
1161 /*-------------------------------------------------------------------------*/
1162 
1163 static void tx_complete (struct urb *urb)
1164 {
1165 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1166 	struct skb_data		*entry = (struct skb_data *) skb->cb;
1167 	struct usbnet		*dev = entry->dev;
1168 
1169 	if (urb->status == 0) {
1170 		if (!(dev->driver_info->flags & FLAG_MULTI_PACKET))
1171 			dev->net->stats.tx_packets++;
1172 		dev->net->stats.tx_bytes += entry->length;
1173 	} else {
1174 		dev->net->stats.tx_errors++;
1175 
1176 		switch (urb->status) {
1177 		case -EPIPE:
1178 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1179 			break;
1180 
1181 		/* software-driven interface shutdown */
1182 		case -ECONNRESET:		// async unlink
1183 		case -ESHUTDOWN:		// hardware gone
1184 			break;
1185 
1186 		// like rx, tx gets controller i/o faults during khubd delays
1187 		// and so it uses the same throttling mechanism.
1188 		case -EPROTO:
1189 		case -ETIME:
1190 		case -EILSEQ:
1191 			usb_mark_last_busy(dev->udev);
1192 			if (!timer_pending (&dev->delay)) {
1193 				mod_timer (&dev->delay,
1194 					jiffies + THROTTLE_JIFFIES);
1195 				netif_dbg(dev, link, dev->net,
1196 					  "tx throttle %d\n", urb->status);
1197 			}
1198 			netif_stop_queue (dev->net);
1199 			break;
1200 		default:
1201 			netif_dbg(dev, tx_err, dev->net,
1202 				  "tx err %d\n", entry->urb->status);
1203 			break;
1204 		}
1205 	}
1206 
1207 	usb_autopm_put_interface_async(dev->intf);
1208 	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1209 }
1210 
1211 /*-------------------------------------------------------------------------*/
1212 
1213 void usbnet_tx_timeout (struct net_device *net)
1214 {
1215 	struct usbnet		*dev = netdev_priv(net);
1216 
1217 	unlink_urbs (dev, &dev->txq);
1218 	tasklet_schedule (&dev->bh);
1219 
1220 	// FIXME: device recovery -- reset?
1221 }
1222 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1223 
1224 /*-------------------------------------------------------------------------*/
1225 
1226 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1227 				     struct net_device *net)
1228 {
1229 	struct usbnet		*dev = netdev_priv(net);
1230 	int			length;
1231 	struct urb		*urb = NULL;
1232 	struct skb_data		*entry;
1233 	struct driver_info	*info = dev->driver_info;
1234 	unsigned long		flags;
1235 	int retval;
1236 
1237 	if (skb)
1238 		skb_tx_timestamp(skb);
1239 
1240 	// some devices want funky USB-level framing, for
1241 	// win32 driver (usually) and/or hardware quirks
1242 	if (info->tx_fixup) {
1243 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1244 		if (!skb) {
1245 			/* packet collected; minidriver waiting for more */
1246 			if (info->flags & FLAG_MULTI_PACKET)
1247 				goto not_drop;
1248 			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1249 			goto drop;
1250 		}
1251 	}
1252 	length = skb->len;
1253 
1254 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1255 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1256 		goto drop;
1257 	}
1258 
1259 	entry = (struct skb_data *) skb->cb;
1260 	entry->urb = urb;
1261 	entry->dev = dev;
1262 	entry->length = length;
1263 
1264 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1265 			skb->data, skb->len, tx_complete, skb);
1266 
1267 	/* don't assume the hardware handles USB_ZERO_PACKET
1268 	 * NOTE:  strictly conforming cdc-ether devices should expect
1269 	 * the ZLP here, but ignore the one-byte packet.
1270 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1271 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1272 	 * packet itself if needed.
1273 	 */
1274 	if (length % dev->maxpacket == 0) {
1275 		if (!(info->flags & FLAG_SEND_ZLP)) {
1276 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1277 				urb->transfer_buffer_length++;
1278 				if (skb_tailroom(skb)) {
1279 					skb->data[skb->len] = 0;
1280 					__skb_put(skb, 1);
1281 				}
1282 			}
1283 		} else
1284 			urb->transfer_flags |= URB_ZERO_PACKET;
1285 	}
1286 
1287 	spin_lock_irqsave(&dev->txq.lock, flags);
1288 	retval = usb_autopm_get_interface_async(dev->intf);
1289 	if (retval < 0) {
1290 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1291 		goto drop;
1292 	}
1293 
1294 #ifdef CONFIG_PM
1295 	/* if this triggers the device is still a sleep */
1296 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1297 		/* transmission will be done in resume */
1298 		usb_anchor_urb(urb, &dev->deferred);
1299 		/* no use to process more packets */
1300 		netif_stop_queue(net);
1301 		usb_put_urb(urb);
1302 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1303 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1304 		goto deferred;
1305 	}
1306 #endif
1307 
1308 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1309 	case -EPIPE:
1310 		netif_stop_queue (net);
1311 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1312 		usb_autopm_put_interface_async(dev->intf);
1313 		break;
1314 	default:
1315 		usb_autopm_put_interface_async(dev->intf);
1316 		netif_dbg(dev, tx_err, dev->net,
1317 			  "tx: submit urb err %d\n", retval);
1318 		break;
1319 	case 0:
1320 		net->trans_start = jiffies;
1321 		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1322 		if (dev->txq.qlen >= TX_QLEN (dev))
1323 			netif_stop_queue (net);
1324 	}
1325 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1326 
1327 	if (retval) {
1328 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1329 drop:
1330 		dev->net->stats.tx_dropped++;
1331 not_drop:
1332 		if (skb)
1333 			dev_kfree_skb_any (skb);
1334 		usb_free_urb (urb);
1335 	} else
1336 		netif_dbg(dev, tx_queued, dev->net,
1337 			  "> tx, len %d, type 0x%x\n", length, skb->protocol);
1338 #ifdef CONFIG_PM
1339 deferred:
1340 #endif
1341 	return NETDEV_TX_OK;
1342 }
1343 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1344 
1345 static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1346 {
1347 	struct urb	*urb;
1348 	int		i;
1349 	int		ret = 0;
1350 
1351 	/* don't refill the queue all at once */
1352 	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1353 		urb = usb_alloc_urb(0, flags);
1354 		if (urb != NULL) {
1355 			ret = rx_submit(dev, urb, flags);
1356 			if (ret)
1357 				goto err;
1358 		} else {
1359 			ret = -ENOMEM;
1360 			goto err;
1361 		}
1362 	}
1363 err:
1364 	return ret;
1365 }
1366 
1367 /*-------------------------------------------------------------------------*/
1368 
1369 // tasklet (work deferred from completions, in_irq) or timer
1370 
1371 static void usbnet_bh (unsigned long param)
1372 {
1373 	struct usbnet		*dev = (struct usbnet *) param;
1374 	struct sk_buff		*skb;
1375 	struct skb_data		*entry;
1376 
1377 	while ((skb = skb_dequeue (&dev->done))) {
1378 		entry = (struct skb_data *) skb->cb;
1379 		switch (entry->state) {
1380 		case rx_done:
1381 			entry->state = rx_cleanup;
1382 			rx_process (dev, skb);
1383 			continue;
1384 		case tx_done:
1385 		case rx_cleanup:
1386 			usb_free_urb (entry->urb);
1387 			dev_kfree_skb (skb);
1388 			continue;
1389 		default:
1390 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1391 		}
1392 	}
1393 
1394 	/* restart RX again after disabling due to high error rate */
1395 	clear_bit(EVENT_RX_KILL, &dev->flags);
1396 
1397 	// waiting for all pending urbs to complete?
1398 	if (dev->wait) {
1399 		if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
1400 			wake_up (dev->wait);
1401 		}
1402 
1403 	// or are we maybe short a few urbs?
1404 	} else if (netif_running (dev->net) &&
1405 		   netif_device_present (dev->net) &&
1406 		   netif_carrier_ok(dev->net) &&
1407 		   !timer_pending (&dev->delay) &&
1408 		   !test_bit (EVENT_RX_HALT, &dev->flags)) {
1409 		int	temp = dev->rxq.qlen;
1410 
1411 		if (temp < RX_QLEN(dev)) {
1412 			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1413 				return;
1414 			if (temp != dev->rxq.qlen)
1415 				netif_dbg(dev, link, dev->net,
1416 					  "rxqlen %d --> %d\n",
1417 					  temp, dev->rxq.qlen);
1418 			if (dev->rxq.qlen < RX_QLEN(dev))
1419 				tasklet_schedule (&dev->bh);
1420 		}
1421 		if (dev->txq.qlen < TX_QLEN (dev))
1422 			netif_wake_queue (dev->net);
1423 	}
1424 }
1425 
1426 
1427 /*-------------------------------------------------------------------------
1428  *
1429  * USB Device Driver support
1430  *
1431  *-------------------------------------------------------------------------*/
1432 
1433 // precondition: never called in_interrupt
1434 
1435 void usbnet_disconnect (struct usb_interface *intf)
1436 {
1437 	struct usbnet		*dev;
1438 	struct usb_device	*xdev;
1439 	struct net_device	*net;
1440 
1441 	dev = usb_get_intfdata(intf);
1442 	usb_set_intfdata(intf, NULL);
1443 	if (!dev)
1444 		return;
1445 
1446 	xdev = interface_to_usbdev (intf);
1447 
1448 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1449 		   intf->dev.driver->name,
1450 		   xdev->bus->bus_name, xdev->devpath,
1451 		   dev->driver_info->description);
1452 
1453 	net = dev->net;
1454 	unregister_netdev (net);
1455 
1456 	cancel_work_sync(&dev->kevent);
1457 
1458 	usb_scuttle_anchored_urbs(&dev->deferred);
1459 
1460 	if (dev->driver_info->unbind)
1461 		dev->driver_info->unbind (dev, intf);
1462 
1463 	usb_kill_urb(dev->interrupt);
1464 	usb_free_urb(dev->interrupt);
1465 
1466 	free_netdev(net);
1467 }
1468 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1469 
1470 static const struct net_device_ops usbnet_netdev_ops = {
1471 	.ndo_open		= usbnet_open,
1472 	.ndo_stop		= usbnet_stop,
1473 	.ndo_start_xmit		= usbnet_start_xmit,
1474 	.ndo_tx_timeout		= usbnet_tx_timeout,
1475 	.ndo_change_mtu		= usbnet_change_mtu,
1476 	.ndo_set_mac_address 	= eth_mac_addr,
1477 	.ndo_validate_addr	= eth_validate_addr,
1478 };
1479 
1480 /*-------------------------------------------------------------------------*/
1481 
1482 // precondition: never called in_interrupt
1483 
1484 static struct device_type wlan_type = {
1485 	.name	= "wlan",
1486 };
1487 
1488 static struct device_type wwan_type = {
1489 	.name	= "wwan",
1490 };
1491 
1492 int
1493 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1494 {
1495 	struct usbnet			*dev;
1496 	struct net_device		*net;
1497 	struct usb_host_interface	*interface;
1498 	struct driver_info		*info;
1499 	struct usb_device		*xdev;
1500 	int				status;
1501 	const char			*name;
1502 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1503 
1504 	/* usbnet already took usb runtime pm, so have to enable the feature
1505 	 * for usb interface, otherwise usb_autopm_get_interface may return
1506 	 * failure if RUNTIME_PM is enabled.
1507 	 */
1508 	if (!driver->supports_autosuspend) {
1509 		driver->supports_autosuspend = 1;
1510 		pm_runtime_enable(&udev->dev);
1511 	}
1512 
1513 	name = udev->dev.driver->name;
1514 	info = (struct driver_info *) prod->driver_info;
1515 	if (!info) {
1516 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1517 		return -ENODEV;
1518 	}
1519 	xdev = interface_to_usbdev (udev);
1520 	interface = udev->cur_altsetting;
1521 
1522 	status = -ENOMEM;
1523 
1524 	// set up our own records
1525 	net = alloc_etherdev(sizeof(*dev));
1526 	if (!net)
1527 		goto out;
1528 
1529 	/* netdev_printk() needs this so do it as early as possible */
1530 	SET_NETDEV_DEV(net, &udev->dev);
1531 
1532 	dev = netdev_priv(net);
1533 	dev->udev = xdev;
1534 	dev->intf = udev;
1535 	dev->driver_info = info;
1536 	dev->driver_name = name;
1537 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1538 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1539 	skb_queue_head_init (&dev->rxq);
1540 	skb_queue_head_init (&dev->txq);
1541 	skb_queue_head_init (&dev->done);
1542 	skb_queue_head_init(&dev->rxq_pause);
1543 	dev->bh.func = usbnet_bh;
1544 	dev->bh.data = (unsigned long) dev;
1545 	INIT_WORK (&dev->kevent, kevent);
1546 	init_usb_anchor(&dev->deferred);
1547 	dev->delay.function = usbnet_bh;
1548 	dev->delay.data = (unsigned long) dev;
1549 	init_timer (&dev->delay);
1550 	mutex_init (&dev->phy_mutex);
1551 	mutex_init(&dev->interrupt_mutex);
1552 	dev->interrupt_count = 0;
1553 
1554 	dev->net = net;
1555 	strcpy (net->name, "usb%d");
1556 	memcpy (net->dev_addr, node_id, sizeof node_id);
1557 
1558 	/* rx and tx sides can use different message sizes;
1559 	 * bind() should set rx_urb_size in that case.
1560 	 */
1561 	dev->hard_mtu = net->mtu + net->hard_header_len;
1562 #if 0
1563 // dma_supported() is deeply broken on almost all architectures
1564 	// possible with some EHCI controllers
1565 	if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1566 		net->features |= NETIF_F_HIGHDMA;
1567 #endif
1568 
1569 	net->netdev_ops = &usbnet_netdev_ops;
1570 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1571 	net->ethtool_ops = &usbnet_ethtool_ops;
1572 
1573 	// allow device-specific bind/init procedures
1574 	// NOTE net->name still not usable ...
1575 	if (info->bind) {
1576 		status = info->bind (dev, udev);
1577 		if (status < 0)
1578 			goto out1;
1579 
1580 		// heuristic:  "usb%d" for links we know are two-host,
1581 		// else "eth%d" when there's reasonable doubt.  userspace
1582 		// can rename the link if it knows better.
1583 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1584 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1585 		     (net->dev_addr [0] & 0x02) == 0))
1586 			strcpy (net->name, "eth%d");
1587 		/* WLAN devices should always be named "wlan%d" */
1588 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1589 			strcpy(net->name, "wlan%d");
1590 		/* WWAN devices should always be named "wwan%d" */
1591 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1592 			strcpy(net->name, "wwan%d");
1593 
1594 		/* devices that cannot do ARP */
1595 		if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1596 			net->flags |= IFF_NOARP;
1597 
1598 		/* maybe the remote can't receive an Ethernet MTU */
1599 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1600 			net->mtu = dev->hard_mtu - net->hard_header_len;
1601 	} else if (!info->in || !info->out)
1602 		status = usbnet_get_endpoints (dev, udev);
1603 	else {
1604 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1605 		dev->out = usb_sndbulkpipe (xdev, info->out);
1606 		if (!(info->flags & FLAG_NO_SETINT))
1607 			status = usb_set_interface (xdev,
1608 				interface->desc.bInterfaceNumber,
1609 				interface->desc.bAlternateSetting);
1610 		else
1611 			status = 0;
1612 
1613 	}
1614 	if (status >= 0 && dev->status)
1615 		status = init_status (dev, udev);
1616 	if (status < 0)
1617 		goto out3;
1618 
1619 	if (!dev->rx_urb_size)
1620 		dev->rx_urb_size = dev->hard_mtu;
1621 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1622 
1623 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1624 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1625 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1626 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1627 
1628 	/* initialize max rx_qlen and tx_qlen */
1629 	usbnet_update_max_qlen(dev);
1630 
1631 	status = register_netdev (net);
1632 	if (status)
1633 		goto out4;
1634 	netif_info(dev, probe, dev->net,
1635 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1636 		   udev->dev.driver->name,
1637 		   xdev->bus->bus_name, xdev->devpath,
1638 		   dev->driver_info->description,
1639 		   net->dev_addr);
1640 
1641 	// ok, it's ready to go.
1642 	usb_set_intfdata (udev, dev);
1643 
1644 	netif_device_attach (net);
1645 
1646 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1647 		usbnet_link_change(dev, 0, 0);
1648 
1649 	return 0;
1650 
1651 out4:
1652 	usb_free_urb(dev->interrupt);
1653 out3:
1654 	if (info->unbind)
1655 		info->unbind (dev, udev);
1656 out1:
1657 	free_netdev(net);
1658 out:
1659 	return status;
1660 }
1661 EXPORT_SYMBOL_GPL(usbnet_probe);
1662 
1663 /*-------------------------------------------------------------------------*/
1664 
1665 /*
1666  * suspend the whole driver as soon as the first interface is suspended
1667  * resume only when the last interface is resumed
1668  */
1669 
1670 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1671 {
1672 	struct usbnet		*dev = usb_get_intfdata(intf);
1673 
1674 	if (!dev->suspend_count++) {
1675 		spin_lock_irq(&dev->txq.lock);
1676 		/* don't autosuspend while transmitting */
1677 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1678 			dev->suspend_count--;
1679 			spin_unlock_irq(&dev->txq.lock);
1680 			return -EBUSY;
1681 		} else {
1682 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1683 			spin_unlock_irq(&dev->txq.lock);
1684 		}
1685 		/*
1686 		 * accelerate emptying of the rx and queues, to avoid
1687 		 * having everything error out.
1688 		 */
1689 		netif_device_detach (dev->net);
1690 		usbnet_terminate_urbs(dev);
1691 		__usbnet_status_stop_force(dev);
1692 
1693 		/*
1694 		 * reattach so runtime management can use and
1695 		 * wake the device
1696 		 */
1697 		netif_device_attach (dev->net);
1698 	}
1699 	return 0;
1700 }
1701 EXPORT_SYMBOL_GPL(usbnet_suspend);
1702 
1703 int usbnet_resume (struct usb_interface *intf)
1704 {
1705 	struct usbnet		*dev = usb_get_intfdata(intf);
1706 	struct sk_buff          *skb;
1707 	struct urb              *res;
1708 	int                     retval;
1709 
1710 	if (!--dev->suspend_count) {
1711 		/* resume interrupt URB if it was previously submitted */
1712 		__usbnet_status_start_force(dev, GFP_NOIO);
1713 
1714 		spin_lock_irq(&dev->txq.lock);
1715 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1716 
1717 			skb = (struct sk_buff *)res->context;
1718 			retval = usb_submit_urb(res, GFP_ATOMIC);
1719 			if (retval < 0) {
1720 				dev_kfree_skb_any(skb);
1721 				usb_free_urb(res);
1722 				usb_autopm_put_interface_async(dev->intf);
1723 			} else {
1724 				dev->net->trans_start = jiffies;
1725 				__skb_queue_tail(&dev->txq, skb);
1726 			}
1727 		}
1728 
1729 		smp_mb();
1730 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1731 		spin_unlock_irq(&dev->txq.lock);
1732 
1733 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1734 			/* handle remote wakeup ASAP */
1735 			if (!dev->wait &&
1736 				netif_device_present(dev->net) &&
1737 				!timer_pending(&dev->delay) &&
1738 				!test_bit(EVENT_RX_HALT, &dev->flags))
1739 					rx_alloc_submit(dev, GFP_NOIO);
1740 
1741 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1742 				netif_tx_wake_all_queues(dev->net);
1743 			tasklet_schedule (&dev->bh);
1744 		}
1745 	}
1746 
1747 	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1748 		usb_autopm_get_interface_no_resume(intf);
1749 
1750 	return 0;
1751 }
1752 EXPORT_SYMBOL_GPL(usbnet_resume);
1753 
1754 /*
1755  * Either a subdriver implements manage_power, then it is assumed to always
1756  * be ready to be suspended or it reports the readiness to be suspended
1757  * explicitly
1758  */
1759 void usbnet_device_suggests_idle(struct usbnet *dev)
1760 {
1761 	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1762 		dev->intf->needs_remote_wakeup = 1;
1763 		usb_autopm_put_interface_async(dev->intf);
1764 	}
1765 }
1766 EXPORT_SYMBOL(usbnet_device_suggests_idle);
1767 
1768 /*
1769  * For devices that can do without special commands
1770  */
1771 int usbnet_manage_power(struct usbnet *dev, int on)
1772 {
1773 	dev->intf->needs_remote_wakeup = on;
1774 	return 0;
1775 }
1776 EXPORT_SYMBOL(usbnet_manage_power);
1777 
1778 void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
1779 {
1780 	/* update link after link is reseted */
1781 	if (link && !need_reset)
1782 		netif_carrier_on(dev->net);
1783 	else
1784 		netif_carrier_off(dev->net);
1785 
1786 	if (need_reset && link)
1787 		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
1788 	else
1789 		usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
1790 }
1791 EXPORT_SYMBOL(usbnet_link_change);
1792 
1793 /*-------------------------------------------------------------------------*/
1794 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1795 			     u16 value, u16 index, void *data, u16 size)
1796 {
1797 	void *buf = NULL;
1798 	int err = -ENOMEM;
1799 
1800 	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
1801 		   " value=0x%04x index=0x%04x size=%d\n",
1802 		   cmd, reqtype, value, index, size);
1803 
1804 	if (data) {
1805 		buf = kmalloc(size, GFP_KERNEL);
1806 		if (!buf)
1807 			goto out;
1808 	}
1809 
1810 	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
1811 			      cmd, reqtype, value, index, buf, size,
1812 			      USB_CTRL_GET_TIMEOUT);
1813 	if (err > 0 && err <= size)
1814 		memcpy(data, buf, err);
1815 	kfree(buf);
1816 out:
1817 	return err;
1818 }
1819 
1820 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1821 			      u16 value, u16 index, const void *data,
1822 			      u16 size)
1823 {
1824 	void *buf = NULL;
1825 	int err = -ENOMEM;
1826 
1827 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
1828 		   " value=0x%04x index=0x%04x size=%d\n",
1829 		   cmd, reqtype, value, index, size);
1830 
1831 	if (data) {
1832 		buf = kmemdup(data, size, GFP_KERNEL);
1833 		if (!buf)
1834 			goto out;
1835 	}
1836 
1837 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
1838 			      cmd, reqtype, value, index, buf, size,
1839 			      USB_CTRL_SET_TIMEOUT);
1840 	kfree(buf);
1841 
1842 out:
1843 	return err;
1844 }
1845 
1846 /*
1847  * The function can't be called inside suspend/resume callback,
1848  * otherwise deadlock will be caused.
1849  */
1850 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1851 		    u16 value, u16 index, void *data, u16 size)
1852 {
1853 	int ret;
1854 
1855 	if (usb_autopm_get_interface(dev->intf) < 0)
1856 		return -ENODEV;
1857 	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
1858 				data, size);
1859 	usb_autopm_put_interface(dev->intf);
1860 	return ret;
1861 }
1862 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
1863 
1864 /*
1865  * The function can't be called inside suspend/resume callback,
1866  * otherwise deadlock will be caused.
1867  */
1868 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1869 		     u16 value, u16 index, const void *data, u16 size)
1870 {
1871 	int ret;
1872 
1873 	if (usb_autopm_get_interface(dev->intf) < 0)
1874 		return -ENODEV;
1875 	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
1876 				 data, size);
1877 	usb_autopm_put_interface(dev->intf);
1878 	return ret;
1879 }
1880 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
1881 
1882 /*
1883  * The function can be called inside suspend/resume callback safely
1884  * and should only be called by suspend/resume callback generally.
1885  */
1886 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
1887 			  u16 value, u16 index, void *data, u16 size)
1888 {
1889 	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
1890 				 data, size);
1891 }
1892 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
1893 
1894 /*
1895  * The function can be called inside suspend/resume callback safely
1896  * and should only be called by suspend/resume callback generally.
1897  */
1898 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
1899 			  u16 value, u16 index, const void *data,
1900 			  u16 size)
1901 {
1902 	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
1903 				  data, size);
1904 }
1905 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
1906 
1907 static void usbnet_async_cmd_cb(struct urb *urb)
1908 {
1909 	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
1910 	int status = urb->status;
1911 
1912 	if (status < 0)
1913 		dev_dbg(&urb->dev->dev, "%s failed with %d",
1914 			__func__, status);
1915 
1916 	kfree(req);
1917 	usb_free_urb(urb);
1918 }
1919 
1920 /*
1921  * The caller must make sure that device can't be put into suspend
1922  * state until the control URB completes.
1923  */
1924 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
1925 			   u16 value, u16 index, const void *data, u16 size)
1926 {
1927 	struct usb_ctrlrequest *req = NULL;
1928 	struct urb *urb;
1929 	int err = -ENOMEM;
1930 	void *buf = NULL;
1931 
1932 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
1933 		   " value=0x%04x index=0x%04x size=%d\n",
1934 		   cmd, reqtype, value, index, size);
1935 
1936 	urb = usb_alloc_urb(0, GFP_ATOMIC);
1937 	if (!urb) {
1938 		netdev_err(dev->net, "Error allocating URB in"
1939 			   " %s!\n", __func__);
1940 		goto fail;
1941 	}
1942 
1943 	if (data) {
1944 		buf = kmemdup(data, size, GFP_ATOMIC);
1945 		if (!buf) {
1946 			netdev_err(dev->net, "Error allocating buffer"
1947 				   " in %s!\n", __func__);
1948 			goto fail_free;
1949 		}
1950 	}
1951 
1952 	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
1953 	if (!req)
1954 		goto fail_free_buf;
1955 
1956 	req->bRequestType = reqtype;
1957 	req->bRequest = cmd;
1958 	req->wValue = cpu_to_le16(value);
1959 	req->wIndex = cpu_to_le16(index);
1960 	req->wLength = cpu_to_le16(size);
1961 
1962 	usb_fill_control_urb(urb, dev->udev,
1963 			     usb_sndctrlpipe(dev->udev, 0),
1964 			     (void *)req, buf, size,
1965 			     usbnet_async_cmd_cb, req);
1966 	urb->transfer_flags |= URB_FREE_BUFFER;
1967 
1968 	err = usb_submit_urb(urb, GFP_ATOMIC);
1969 	if (err < 0) {
1970 		netdev_err(dev->net, "Error submitting the control"
1971 			   " message: status=%d\n", err);
1972 		goto fail_free;
1973 	}
1974 	return 0;
1975 
1976 fail_free_buf:
1977 	kfree(buf);
1978 fail_free:
1979 	kfree(req);
1980 	usb_free_urb(urb);
1981 fail:
1982 	return err;
1983 
1984 }
1985 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
1986 /*-------------------------------------------------------------------------*/
1987 
1988 static int __init usbnet_init(void)
1989 {
1990 	/* Compiler should optimize this out. */
1991 	BUILD_BUG_ON(
1992 		FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
1993 
1994 	eth_random_addr(node_id);
1995 	return 0;
1996 }
1997 module_init(usbnet_init);
1998 
1999 static void __exit usbnet_exit(void)
2000 {
2001 }
2002 module_exit(usbnet_exit);
2003 
2004 MODULE_AUTHOR("David Brownell");
2005 MODULE_DESCRIPTION("USB network driver framework");
2006 MODULE_LICENSE("GPL");
2007