xref: /openbmc/linux/drivers/net/usb/usbnet.c (revision 206204a1)
1 /*
2  * USB Network driver infrastructure
3  * Copyright (C) 2000-2005 by David Brownell
4  * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 /*
21  * This is a generic "USB networking" framework that works with several
22  * kinds of full and high speed networking devices:  host-to-host cables,
23  * smart usb peripherals, and actual Ethernet adapters.
24  *
25  * These devices usually differ in terms of control protocols (if they
26  * even have one!) and sometimes they define new framing to wrap or batch
27  * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
28  * so interface (un)binding, endpoint I/O queues, fault handling, and other
29  * issues can usefully be addressed by this framework.
30  */
31 
32 // #define	DEBUG			// error path messages, extra info
33 // #define	VERBOSE			// more; success messages
34 
35 #include <linux/module.h>
36 #include <linux/init.h>
37 #include <linux/netdevice.h>
38 #include <linux/etherdevice.h>
39 #include <linux/ctype.h>
40 #include <linux/ethtool.h>
41 #include <linux/workqueue.h>
42 #include <linux/mii.h>
43 #include <linux/usb.h>
44 #include <linux/usb/usbnet.h>
45 #include <linux/slab.h>
46 #include <linux/kernel.h>
47 #include <linux/pm_runtime.h>
48 
49 #define DRIVER_VERSION		"22-Aug-2005"
50 
51 
52 /*-------------------------------------------------------------------------*/
53 
54 /*
55  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
56  * Several dozen bytes of IPv4 data can fit in two such transactions.
57  * One maximum size Ethernet packet takes twenty four of them.
58  * For high speed, each frame comfortably fits almost 36 max size
59  * Ethernet packets (so queues should be bigger).
60  *
61  * The goal is to let the USB host controller be busy for 5msec or
62  * more before an irq is required, under load.  Jumbograms change
63  * the equation.
64  */
65 #define	MAX_QUEUE_MEMORY	(60 * 1518)
66 #define	RX_QLEN(dev)		((dev)->rx_qlen)
67 #define	TX_QLEN(dev)		((dev)->tx_qlen)
68 
69 // reawaken network queue this soon after stopping; else watchdog barks
70 #define TX_TIMEOUT_JIFFIES	(5*HZ)
71 
72 // throttle rx/tx briefly after some faults, so khubd might disconnect()
73 // us (it polls at HZ/4 usually) before we report too many false errors.
74 #define THROTTLE_JIFFIES	(HZ/8)
75 
76 // between wakeups
77 #define UNLINK_TIMEOUT_MS	3
78 
79 /*-------------------------------------------------------------------------*/
80 
81 // randomly generated ethernet address
82 static u8	node_id [ETH_ALEN];
83 
84 static const char driver_name [] = "usbnet";
85 
86 /* use ethtool to change the level for any given device */
87 static int msg_level = -1;
88 module_param (msg_level, int, 0);
89 MODULE_PARM_DESC (msg_level, "Override default message level");
90 
91 /*-------------------------------------------------------------------------*/
92 
93 /* handles CDC Ethernet and many other network "bulk data" interfaces */
94 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
95 {
96 	int				tmp;
97 	struct usb_host_interface	*alt = NULL;
98 	struct usb_host_endpoint	*in = NULL, *out = NULL;
99 	struct usb_host_endpoint	*status = NULL;
100 
101 	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
102 		unsigned	ep;
103 
104 		in = out = status = NULL;
105 		alt = intf->altsetting + tmp;
106 
107 		/* take the first altsetting with in-bulk + out-bulk;
108 		 * remember any status endpoint, just in case;
109 		 * ignore other endpoints and altsettings.
110 		 */
111 		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
112 			struct usb_host_endpoint	*e;
113 			int				intr = 0;
114 
115 			e = alt->endpoint + ep;
116 			switch (e->desc.bmAttributes) {
117 			case USB_ENDPOINT_XFER_INT:
118 				if (!usb_endpoint_dir_in(&e->desc))
119 					continue;
120 				intr = 1;
121 				/* FALLTHROUGH */
122 			case USB_ENDPOINT_XFER_BULK:
123 				break;
124 			default:
125 				continue;
126 			}
127 			if (usb_endpoint_dir_in(&e->desc)) {
128 				if (!intr && !in)
129 					in = e;
130 				else if (intr && !status)
131 					status = e;
132 			} else {
133 				if (!out)
134 					out = e;
135 			}
136 		}
137 		if (in && out)
138 			break;
139 	}
140 	if (!alt || !in || !out)
141 		return -EINVAL;
142 
143 	if (alt->desc.bAlternateSetting != 0 ||
144 	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
145 		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
146 				alt->desc.bAlternateSetting);
147 		if (tmp < 0)
148 			return tmp;
149 	}
150 
151 	dev->in = usb_rcvbulkpipe (dev->udev,
152 			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
153 	dev->out = usb_sndbulkpipe (dev->udev,
154 			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
155 	dev->status = status;
156 	return 0;
157 }
158 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
159 
160 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
161 {
162 	int 		tmp, i;
163 	unsigned char	buf [13];
164 
165 	tmp = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
166 	if (tmp != 12) {
167 		dev_dbg(&dev->udev->dev,
168 			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
169 		if (tmp >= 0)
170 			tmp = -EINVAL;
171 		return tmp;
172 	}
173 	for (i = tmp = 0; i < 6; i++, tmp += 2)
174 		dev->net->dev_addr [i] =
175 			(hex_to_bin(buf[tmp]) << 4) + hex_to_bin(buf[tmp + 1]);
176 	return 0;
177 }
178 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
179 
180 static void intr_complete (struct urb *urb)
181 {
182 	struct usbnet	*dev = urb->context;
183 	int		status = urb->status;
184 
185 	switch (status) {
186 	/* success */
187 	case 0:
188 		dev->driver_info->status(dev, urb);
189 		break;
190 
191 	/* software-driven interface shutdown */
192 	case -ENOENT:		/* urb killed */
193 	case -ESHUTDOWN:	/* hardware gone */
194 		netif_dbg(dev, ifdown, dev->net,
195 			  "intr shutdown, code %d\n", status);
196 		return;
197 
198 	/* NOTE:  not throttling like RX/TX, since this endpoint
199 	 * already polls infrequently
200 	 */
201 	default:
202 		netdev_dbg(dev->net, "intr status %d\n", status);
203 		break;
204 	}
205 
206 	status = usb_submit_urb (urb, GFP_ATOMIC);
207 	if (status != 0)
208 		netif_err(dev, timer, dev->net,
209 			  "intr resubmit --> %d\n", status);
210 }
211 
212 static int init_status (struct usbnet *dev, struct usb_interface *intf)
213 {
214 	char		*buf = NULL;
215 	unsigned	pipe = 0;
216 	unsigned	maxp;
217 	unsigned	period;
218 
219 	if (!dev->driver_info->status)
220 		return 0;
221 
222 	pipe = usb_rcvintpipe (dev->udev,
223 			dev->status->desc.bEndpointAddress
224 				& USB_ENDPOINT_NUMBER_MASK);
225 	maxp = usb_maxpacket (dev->udev, pipe, 0);
226 
227 	/* avoid 1 msec chatter:  min 8 msec poll rate */
228 	period = max ((int) dev->status->desc.bInterval,
229 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
230 
231 	buf = kmalloc (maxp, GFP_KERNEL);
232 	if (buf) {
233 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
234 		if (!dev->interrupt) {
235 			kfree (buf);
236 			return -ENOMEM;
237 		} else {
238 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
239 				buf, maxp, intr_complete, dev, period);
240 			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
241 			dev_dbg(&intf->dev,
242 				"status ep%din, %d bytes period %d\n",
243 				usb_pipeendpoint(pipe), maxp, period);
244 		}
245 	}
246 	return 0;
247 }
248 
249 /* Submit the interrupt URB if not previously submitted, increasing refcount */
250 int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
251 {
252 	int ret = 0;
253 
254 	WARN_ON_ONCE(dev->interrupt == NULL);
255 	if (dev->interrupt) {
256 		mutex_lock(&dev->interrupt_mutex);
257 
258 		if (++dev->interrupt_count == 1)
259 			ret = usb_submit_urb(dev->interrupt, mem_flags);
260 
261 		dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
262 			dev->interrupt_count);
263 		mutex_unlock(&dev->interrupt_mutex);
264 	}
265 	return ret;
266 }
267 EXPORT_SYMBOL_GPL(usbnet_status_start);
268 
269 /* For resume; submit interrupt URB if previously submitted */
270 static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
271 {
272 	int ret = 0;
273 
274 	mutex_lock(&dev->interrupt_mutex);
275 	if (dev->interrupt_count) {
276 		ret = usb_submit_urb(dev->interrupt, mem_flags);
277 		dev_dbg(&dev->udev->dev,
278 			"submitted interrupt URB for resume\n");
279 	}
280 	mutex_unlock(&dev->interrupt_mutex);
281 	return ret;
282 }
283 
284 /* Kill the interrupt URB if all submitters want it killed */
285 void usbnet_status_stop(struct usbnet *dev)
286 {
287 	if (dev->interrupt) {
288 		mutex_lock(&dev->interrupt_mutex);
289 		WARN_ON(dev->interrupt_count == 0);
290 
291 		if (dev->interrupt_count && --dev->interrupt_count == 0)
292 			usb_kill_urb(dev->interrupt);
293 
294 		dev_dbg(&dev->udev->dev,
295 			"decremented interrupt URB count to %d\n",
296 			dev->interrupt_count);
297 		mutex_unlock(&dev->interrupt_mutex);
298 	}
299 }
300 EXPORT_SYMBOL_GPL(usbnet_status_stop);
301 
302 /* For suspend; always kill interrupt URB */
303 static void __usbnet_status_stop_force(struct usbnet *dev)
304 {
305 	if (dev->interrupt) {
306 		mutex_lock(&dev->interrupt_mutex);
307 		usb_kill_urb(dev->interrupt);
308 		dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
309 		mutex_unlock(&dev->interrupt_mutex);
310 	}
311 }
312 
313 /* Passes this packet up the stack, updating its accounting.
314  * Some link protocols batch packets, so their rx_fixup paths
315  * can return clones as well as just modify the original skb.
316  */
317 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
318 {
319 	int	status;
320 
321 	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
322 		skb_queue_tail(&dev->rxq_pause, skb);
323 		return;
324 	}
325 
326 	skb->protocol = eth_type_trans (skb, dev->net);
327 	dev->net->stats.rx_packets++;
328 	dev->net->stats.rx_bytes += skb->len;
329 
330 	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
331 		  skb->len + sizeof (struct ethhdr), skb->protocol);
332 	memset (skb->cb, 0, sizeof (struct skb_data));
333 
334 	if (skb_defer_rx_timestamp(skb))
335 		return;
336 
337 	status = netif_rx (skb);
338 	if (status != NET_RX_SUCCESS)
339 		netif_dbg(dev, rx_err, dev->net,
340 			  "netif_rx status %d\n", status);
341 }
342 EXPORT_SYMBOL_GPL(usbnet_skb_return);
343 
344 /* must be called if hard_mtu or rx_urb_size changed */
345 void usbnet_update_max_qlen(struct usbnet *dev)
346 {
347 	enum usb_device_speed speed = dev->udev->speed;
348 
349 	switch (speed) {
350 	case USB_SPEED_HIGH:
351 		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
352 		dev->tx_qlen = MAX_QUEUE_MEMORY / dev->hard_mtu;
353 		break;
354 	case USB_SPEED_SUPER:
355 		/*
356 		 * Not take default 5ms qlen for super speed HC to
357 		 * save memory, and iperf tests show 2.5ms qlen can
358 		 * work well
359 		 */
360 		dev->rx_qlen = 5 * MAX_QUEUE_MEMORY / dev->rx_urb_size;
361 		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
362 		break;
363 	default:
364 		dev->rx_qlen = dev->tx_qlen = 4;
365 	}
366 }
367 EXPORT_SYMBOL_GPL(usbnet_update_max_qlen);
368 
369 
370 /*-------------------------------------------------------------------------
371  *
372  * Network Device Driver (peer link to "Host Device", from USB host)
373  *
374  *-------------------------------------------------------------------------*/
375 
376 int usbnet_change_mtu (struct net_device *net, int new_mtu)
377 {
378 	struct usbnet	*dev = netdev_priv(net);
379 	int		ll_mtu = new_mtu + net->hard_header_len;
380 	int		old_hard_mtu = dev->hard_mtu;
381 	int		old_rx_urb_size = dev->rx_urb_size;
382 
383 	if (new_mtu <= 0)
384 		return -EINVAL;
385 	// no second zero-length packet read wanted after mtu-sized packets
386 	if ((ll_mtu % dev->maxpacket) == 0)
387 		return -EDOM;
388 	net->mtu = new_mtu;
389 
390 	dev->hard_mtu = net->mtu + net->hard_header_len;
391 	if (dev->rx_urb_size == old_hard_mtu) {
392 		dev->rx_urb_size = dev->hard_mtu;
393 		if (dev->rx_urb_size > old_rx_urb_size)
394 			usbnet_unlink_rx_urbs(dev);
395 	}
396 
397 	/* max qlen depend on hard_mtu and rx_urb_size */
398 	usbnet_update_max_qlen(dev);
399 
400 	return 0;
401 }
402 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
403 
404 /* The caller must hold list->lock */
405 static void __usbnet_queue_skb(struct sk_buff_head *list,
406 			struct sk_buff *newsk, enum skb_state state)
407 {
408 	struct skb_data *entry = (struct skb_data *) newsk->cb;
409 
410 	__skb_queue_tail(list, newsk);
411 	entry->state = state;
412 }
413 
414 /*-------------------------------------------------------------------------*/
415 
416 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
417  * completion callbacks.  2.5 should have fixed those bugs...
418  */
419 
420 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
421 		struct sk_buff_head *list, enum skb_state state)
422 {
423 	unsigned long		flags;
424 	enum skb_state 		old_state;
425 	struct skb_data *entry = (struct skb_data *) skb->cb;
426 
427 	spin_lock_irqsave(&list->lock, flags);
428 	old_state = entry->state;
429 	entry->state = state;
430 	__skb_unlink(skb, list);
431 	spin_unlock(&list->lock);
432 	spin_lock(&dev->done.lock);
433 	__skb_queue_tail(&dev->done, skb);
434 	if (dev->done.qlen == 1)
435 		tasklet_schedule(&dev->bh);
436 	spin_unlock_irqrestore(&dev->done.lock, flags);
437 	return old_state;
438 }
439 
440 /* some work can't be done in tasklets, so we use keventd
441  *
442  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
443  * but tasklet_schedule() doesn't.  hope the failure is rare.
444  */
445 void usbnet_defer_kevent (struct usbnet *dev, int work)
446 {
447 	set_bit (work, &dev->flags);
448 	if (!schedule_work (&dev->kevent)) {
449 		if (net_ratelimit())
450 			netdev_err(dev->net, "kevent %d may have been dropped\n", work);
451 	} else {
452 		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
453 	}
454 }
455 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
456 
457 /*-------------------------------------------------------------------------*/
458 
459 static void rx_complete (struct urb *urb);
460 
461 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
462 {
463 	struct sk_buff		*skb;
464 	struct skb_data		*entry;
465 	int			retval = 0;
466 	unsigned long		lockflags;
467 	size_t			size = dev->rx_urb_size;
468 
469 	/* prevent rx skb allocation when error ratio is high */
470 	if (test_bit(EVENT_RX_KILL, &dev->flags)) {
471 		usb_free_urb(urb);
472 		return -ENOLINK;
473 	}
474 
475 	skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
476 	if (!skb) {
477 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
478 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
479 		usb_free_urb (urb);
480 		return -ENOMEM;
481 	}
482 
483 	entry = (struct skb_data *) skb->cb;
484 	entry->urb = urb;
485 	entry->dev = dev;
486 	entry->length = 0;
487 
488 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
489 		skb->data, size, rx_complete, skb);
490 
491 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
492 
493 	if (netif_running (dev->net) &&
494 	    netif_device_present (dev->net) &&
495 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
496 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
497 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
498 		case -EPIPE:
499 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
500 			break;
501 		case -ENOMEM:
502 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
503 			break;
504 		case -ENODEV:
505 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
506 			netif_device_detach (dev->net);
507 			break;
508 		case -EHOSTUNREACH:
509 			retval = -ENOLINK;
510 			break;
511 		default:
512 			netif_dbg(dev, rx_err, dev->net,
513 				  "rx submit, %d\n", retval);
514 			tasklet_schedule (&dev->bh);
515 			break;
516 		case 0:
517 			__usbnet_queue_skb(&dev->rxq, skb, rx_start);
518 		}
519 	} else {
520 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
521 		retval = -ENOLINK;
522 	}
523 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
524 	if (retval) {
525 		dev_kfree_skb_any (skb);
526 		usb_free_urb (urb);
527 	}
528 	return retval;
529 }
530 
531 
532 /*-------------------------------------------------------------------------*/
533 
534 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
535 {
536 	if (dev->driver_info->rx_fixup &&
537 	    !dev->driver_info->rx_fixup (dev, skb)) {
538 		/* With RX_ASSEMBLE, rx_fixup() must update counters */
539 		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
540 			dev->net->stats.rx_errors++;
541 		goto done;
542 	}
543 	// else network stack removes extra byte if we forced a short packet
544 
545 	/* all data was already cloned from skb inside the driver */
546 	if (dev->driver_info->flags & FLAG_MULTI_PACKET)
547 		goto done;
548 
549 	if (skb->len < ETH_HLEN) {
550 		dev->net->stats.rx_errors++;
551 		dev->net->stats.rx_length_errors++;
552 		netif_dbg(dev, rx_err, dev->net, "rx length %d\n", skb->len);
553 	} else {
554 		usbnet_skb_return(dev, skb);
555 		return;
556 	}
557 
558 done:
559 	skb_queue_tail(&dev->done, skb);
560 }
561 
562 /*-------------------------------------------------------------------------*/
563 
564 static void rx_complete (struct urb *urb)
565 {
566 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
567 	struct skb_data		*entry = (struct skb_data *) skb->cb;
568 	struct usbnet		*dev = entry->dev;
569 	int			urb_status = urb->status;
570 	enum skb_state		state;
571 
572 	skb_put (skb, urb->actual_length);
573 	state = rx_done;
574 	entry->urb = NULL;
575 
576 	switch (urb_status) {
577 	/* success */
578 	case 0:
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_WAITQUEUE(wait, current);
756 	int temp;
757 
758 	/* ensure there are no more active urbs */
759 	add_wait_queue(&dev->wait, &wait);
760 	set_current_state(TASK_UNINTERRUPTIBLE);
761 	temp = unlink_urbs(dev, &dev->txq) +
762 		unlink_urbs(dev, &dev->rxq);
763 
764 	/* maybe wait for deletions to finish. */
765 	while (!skb_queue_empty(&dev->rxq)
766 		&& !skb_queue_empty(&dev->txq)
767 		&& !skb_queue_empty(&dev->done)) {
768 			schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
769 			set_current_state(TASK_UNINTERRUPTIBLE);
770 			netif_dbg(dev, ifdown, dev->net,
771 				  "waited for %d urb completions\n", temp);
772 	}
773 	set_current_state(TASK_RUNNING);
774 	remove_wait_queue(&dev->wait, &wait);
775 }
776 
777 int usbnet_stop (struct net_device *net)
778 {
779 	struct usbnet		*dev = netdev_priv(net);
780 	struct driver_info	*info = dev->driver_info;
781 	int			retval, pm;
782 
783 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
784 	netif_stop_queue (net);
785 
786 	netif_info(dev, ifdown, dev->net,
787 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
788 		   net->stats.rx_packets, net->stats.tx_packets,
789 		   net->stats.rx_errors, net->stats.tx_errors);
790 
791 	/* to not race resume */
792 	pm = usb_autopm_get_interface(dev->intf);
793 	/* allow minidriver to stop correctly (wireless devices to turn off
794 	 * radio etc) */
795 	if (info->stop) {
796 		retval = info->stop(dev);
797 		if (retval < 0)
798 			netif_info(dev, ifdown, dev->net,
799 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
800 				   retval,
801 				   dev->udev->bus->bus_name, dev->udev->devpath,
802 				   info->description);
803 	}
804 
805 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
806 		usbnet_terminate_urbs(dev);
807 
808 	usbnet_status_stop(dev);
809 
810 	usbnet_purge_paused_rxq(dev);
811 
812 	/* deferred work (task, timer, softirq) must also stop.
813 	 * can't flush_scheduled_work() until we drop rtnl (later),
814 	 * else workers could deadlock; so make workers a NOP.
815 	 */
816 	dev->flags = 0;
817 	del_timer_sync (&dev->delay);
818 	tasklet_kill (&dev->bh);
819 	if (!pm)
820 		usb_autopm_put_interface(dev->intf);
821 
822 	if (info->manage_power &&
823 	    !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags))
824 		info->manage_power(dev, 0);
825 	else
826 		usb_autopm_put_interface(dev->intf);
827 
828 	return 0;
829 }
830 EXPORT_SYMBOL_GPL(usbnet_stop);
831 
832 /*-------------------------------------------------------------------------*/
833 
834 // posts reads, and enables write queuing
835 
836 // precondition: never called in_interrupt
837 
838 int usbnet_open (struct net_device *net)
839 {
840 	struct usbnet		*dev = netdev_priv(net);
841 	int			retval;
842 	struct driver_info	*info = dev->driver_info;
843 
844 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
845 		netif_info(dev, ifup, dev->net,
846 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
847 			   retval,
848 			   dev->udev->bus->bus_name,
849 			   dev->udev->devpath,
850 			   info->description);
851 		goto done_nopm;
852 	}
853 
854 	// put into "known safe" state
855 	if (info->reset && (retval = info->reset (dev)) < 0) {
856 		netif_info(dev, ifup, dev->net,
857 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
858 			   retval,
859 			   dev->udev->bus->bus_name,
860 			   dev->udev->devpath,
861 			   info->description);
862 		goto done;
863 	}
864 
865 	/* hard_mtu or rx_urb_size may change in reset() */
866 	usbnet_update_max_qlen(dev);
867 
868 	// insist peer be connected
869 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
870 		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
871 		goto done;
872 	}
873 
874 	/* start any status interrupt transfer */
875 	if (dev->interrupt) {
876 		retval = usbnet_status_start(dev, GFP_KERNEL);
877 		if (retval < 0) {
878 			netif_err(dev, ifup, dev->net,
879 				  "intr submit %d\n", retval);
880 			goto done;
881 		}
882 	}
883 
884 	set_bit(EVENT_DEV_OPEN, &dev->flags);
885 	netif_start_queue (net);
886 	netif_info(dev, ifup, dev->net,
887 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
888 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
889 		   dev->net->mtu,
890 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
891 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
892 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
893 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
894 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
895 		   "simple");
896 
897 	/* reset rx error state */
898 	dev->pkt_cnt = 0;
899 	dev->pkt_err = 0;
900 	clear_bit(EVENT_RX_KILL, &dev->flags);
901 
902 	// delay posting reads until we're fully open
903 	tasklet_schedule (&dev->bh);
904 	if (info->manage_power) {
905 		retval = info->manage_power(dev, 1);
906 		if (retval < 0) {
907 			retval = 0;
908 			set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
909 		} else {
910 			usb_autopm_put_interface(dev->intf);
911 		}
912 	}
913 	return retval;
914 done:
915 	usb_autopm_put_interface(dev->intf);
916 done_nopm:
917 	return retval;
918 }
919 EXPORT_SYMBOL_GPL(usbnet_open);
920 
921 /*-------------------------------------------------------------------------*/
922 
923 /* ethtool methods; minidrivers may need to add some more, but
924  * they'll probably want to use this base set.
925  */
926 
927 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
928 {
929 	struct usbnet *dev = netdev_priv(net);
930 
931 	if (!dev->mii.mdio_read)
932 		return -EOPNOTSUPP;
933 
934 	return mii_ethtool_gset(&dev->mii, cmd);
935 }
936 EXPORT_SYMBOL_GPL(usbnet_get_settings);
937 
938 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
939 {
940 	struct usbnet *dev = netdev_priv(net);
941 	int retval;
942 
943 	if (!dev->mii.mdio_write)
944 		return -EOPNOTSUPP;
945 
946 	retval = mii_ethtool_sset(&dev->mii, cmd);
947 
948 	/* link speed/duplex might have changed */
949 	if (dev->driver_info->link_reset)
950 		dev->driver_info->link_reset(dev);
951 
952 	/* hard_mtu or rx_urb_size may change in link_reset() */
953 	usbnet_update_max_qlen(dev);
954 
955 	return retval;
956 
957 }
958 EXPORT_SYMBOL_GPL(usbnet_set_settings);
959 
960 u32 usbnet_get_link (struct net_device *net)
961 {
962 	struct usbnet *dev = netdev_priv(net);
963 
964 	/* If a check_connect is defined, return its result */
965 	if (dev->driver_info->check_connect)
966 		return dev->driver_info->check_connect (dev) == 0;
967 
968 	/* if the device has mii operations, use those */
969 	if (dev->mii.mdio_read)
970 		return mii_link_ok(&dev->mii);
971 
972 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
973 	return ethtool_op_get_link(net);
974 }
975 EXPORT_SYMBOL_GPL(usbnet_get_link);
976 
977 int usbnet_nway_reset(struct net_device *net)
978 {
979 	struct usbnet *dev = netdev_priv(net);
980 
981 	if (!dev->mii.mdio_write)
982 		return -EOPNOTSUPP;
983 
984 	return mii_nway_restart(&dev->mii);
985 }
986 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
987 
988 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
989 {
990 	struct usbnet *dev = netdev_priv(net);
991 
992 	strlcpy (info->driver, dev->driver_name, sizeof info->driver);
993 	strlcpy (info->version, DRIVER_VERSION, sizeof info->version);
994 	strlcpy (info->fw_version, dev->driver_info->description,
995 		sizeof info->fw_version);
996 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
997 }
998 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
999 
1000 u32 usbnet_get_msglevel (struct net_device *net)
1001 {
1002 	struct usbnet *dev = netdev_priv(net);
1003 
1004 	return dev->msg_enable;
1005 }
1006 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
1007 
1008 void usbnet_set_msglevel (struct net_device *net, u32 level)
1009 {
1010 	struct usbnet *dev = netdev_priv(net);
1011 
1012 	dev->msg_enable = level;
1013 }
1014 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
1015 
1016 /* drivers may override default ethtool_ops in their bind() routine */
1017 static const struct ethtool_ops usbnet_ethtool_ops = {
1018 	.get_settings		= usbnet_get_settings,
1019 	.set_settings		= usbnet_set_settings,
1020 	.get_link		= usbnet_get_link,
1021 	.nway_reset		= usbnet_nway_reset,
1022 	.get_drvinfo		= usbnet_get_drvinfo,
1023 	.get_msglevel		= usbnet_get_msglevel,
1024 	.set_msglevel		= usbnet_set_msglevel,
1025 	.get_ts_info		= ethtool_op_get_ts_info,
1026 };
1027 
1028 /*-------------------------------------------------------------------------*/
1029 
1030 static void __handle_link_change(struct usbnet *dev)
1031 {
1032 	if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
1033 		return;
1034 
1035 	if (!netif_carrier_ok(dev->net)) {
1036 		/* kill URBs for reading packets to save bus bandwidth */
1037 		unlink_urbs(dev, &dev->rxq);
1038 
1039 		/*
1040 		 * tx_timeout will unlink URBs for sending packets and
1041 		 * tx queue is stopped by netcore after link becomes off
1042 		 */
1043 	} else {
1044 		/* submitting URBs for reading packets */
1045 		tasklet_schedule(&dev->bh);
1046 	}
1047 
1048 	/* hard_mtu or rx_urb_size may change during link change */
1049 	usbnet_update_max_qlen(dev);
1050 
1051 	clear_bit(EVENT_LINK_CHANGE, &dev->flags);
1052 }
1053 
1054 /* work that cannot be done in interrupt context uses keventd.
1055  *
1056  * NOTE:  with 2.5 we could do more of this using completion callbacks,
1057  * especially now that control transfers can be queued.
1058  */
1059 static void
1060 kevent (struct work_struct *work)
1061 {
1062 	struct usbnet		*dev =
1063 		container_of(work, struct usbnet, kevent);
1064 	int			status;
1065 
1066 	/* usb_clear_halt() needs a thread context */
1067 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
1068 		unlink_urbs (dev, &dev->txq);
1069 		status = usb_autopm_get_interface(dev->intf);
1070 		if (status < 0)
1071 			goto fail_pipe;
1072 		status = usb_clear_halt (dev->udev, dev->out);
1073 		usb_autopm_put_interface(dev->intf);
1074 		if (status < 0 &&
1075 		    status != -EPIPE &&
1076 		    status != -ESHUTDOWN) {
1077 			if (netif_msg_tx_err (dev))
1078 fail_pipe:
1079 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
1080 					   status);
1081 		} else {
1082 			clear_bit (EVENT_TX_HALT, &dev->flags);
1083 			if (status != -ESHUTDOWN)
1084 				netif_wake_queue (dev->net);
1085 		}
1086 	}
1087 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
1088 		unlink_urbs (dev, &dev->rxq);
1089 		status = usb_autopm_get_interface(dev->intf);
1090 		if (status < 0)
1091 			goto fail_halt;
1092 		status = usb_clear_halt (dev->udev, dev->in);
1093 		usb_autopm_put_interface(dev->intf);
1094 		if (status < 0 &&
1095 		    status != -EPIPE &&
1096 		    status != -ESHUTDOWN) {
1097 			if (netif_msg_rx_err (dev))
1098 fail_halt:
1099 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
1100 					   status);
1101 		} else {
1102 			clear_bit (EVENT_RX_HALT, &dev->flags);
1103 			tasklet_schedule (&dev->bh);
1104 		}
1105 	}
1106 
1107 	/* tasklet could resubmit itself forever if memory is tight */
1108 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
1109 		struct urb	*urb = NULL;
1110 		int resched = 1;
1111 
1112 		if (netif_running (dev->net))
1113 			urb = usb_alloc_urb (0, GFP_KERNEL);
1114 		else
1115 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1116 		if (urb != NULL) {
1117 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1118 			status = usb_autopm_get_interface(dev->intf);
1119 			if (status < 0) {
1120 				usb_free_urb(urb);
1121 				goto fail_lowmem;
1122 			}
1123 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
1124 				resched = 0;
1125 			usb_autopm_put_interface(dev->intf);
1126 fail_lowmem:
1127 			if (resched)
1128 				tasklet_schedule (&dev->bh);
1129 		}
1130 	}
1131 
1132 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
1133 		struct driver_info	*info = dev->driver_info;
1134 		int			retval = 0;
1135 
1136 		clear_bit (EVENT_LINK_RESET, &dev->flags);
1137 		status = usb_autopm_get_interface(dev->intf);
1138 		if (status < 0)
1139 			goto skip_reset;
1140 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1141 			usb_autopm_put_interface(dev->intf);
1142 skip_reset:
1143 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1144 				    retval,
1145 				    dev->udev->bus->bus_name,
1146 				    dev->udev->devpath,
1147 				    info->description);
1148 		} else {
1149 			usb_autopm_put_interface(dev->intf);
1150 		}
1151 
1152 		/* handle link change from link resetting */
1153 		__handle_link_change(dev);
1154 	}
1155 
1156 	if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
1157 		__handle_link_change(dev);
1158 
1159 	if (dev->flags)
1160 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1161 }
1162 
1163 /*-------------------------------------------------------------------------*/
1164 
1165 static void tx_complete (struct urb *urb)
1166 {
1167 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1168 	struct skb_data		*entry = (struct skb_data *) skb->cb;
1169 	struct usbnet		*dev = entry->dev;
1170 
1171 	if (urb->status == 0) {
1172 		if (!(dev->driver_info->flags & FLAG_MULTI_PACKET))
1173 			dev->net->stats.tx_packets++;
1174 		dev->net->stats.tx_bytes += entry->length;
1175 	} else {
1176 		dev->net->stats.tx_errors++;
1177 
1178 		switch (urb->status) {
1179 		case -EPIPE:
1180 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1181 			break;
1182 
1183 		/* software-driven interface shutdown */
1184 		case -ECONNRESET:		// async unlink
1185 		case -ESHUTDOWN:		// hardware gone
1186 			break;
1187 
1188 		// like rx, tx gets controller i/o faults during khubd delays
1189 		// and so it uses the same throttling mechanism.
1190 		case -EPROTO:
1191 		case -ETIME:
1192 		case -EILSEQ:
1193 			usb_mark_last_busy(dev->udev);
1194 			if (!timer_pending (&dev->delay)) {
1195 				mod_timer (&dev->delay,
1196 					jiffies + THROTTLE_JIFFIES);
1197 				netif_dbg(dev, link, dev->net,
1198 					  "tx throttle %d\n", urb->status);
1199 			}
1200 			netif_stop_queue (dev->net);
1201 			break;
1202 		default:
1203 			netif_dbg(dev, tx_err, dev->net,
1204 				  "tx err %d\n", entry->urb->status);
1205 			break;
1206 		}
1207 	}
1208 
1209 	usb_autopm_put_interface_async(dev->intf);
1210 	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1211 }
1212 
1213 /*-------------------------------------------------------------------------*/
1214 
1215 void usbnet_tx_timeout (struct net_device *net)
1216 {
1217 	struct usbnet		*dev = netdev_priv(net);
1218 
1219 	unlink_urbs (dev, &dev->txq);
1220 	tasklet_schedule (&dev->bh);
1221 
1222 	// FIXME: device recovery -- reset?
1223 }
1224 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1225 
1226 /*-------------------------------------------------------------------------*/
1227 
1228 static int build_dma_sg(const struct sk_buff *skb, struct urb *urb)
1229 {
1230 	unsigned num_sgs, total_len = 0;
1231 	int i, s = 0;
1232 
1233 	num_sgs = skb_shinfo(skb)->nr_frags + 1;
1234 	if (num_sgs == 1)
1235 		return 0;
1236 
1237 	/* reserve one for zero packet */
1238 	urb->sg = kmalloc((num_sgs + 1) * sizeof(struct scatterlist),
1239 			  GFP_ATOMIC);
1240 	if (!urb->sg)
1241 		return -ENOMEM;
1242 
1243 	urb->num_sgs = num_sgs;
1244 	sg_init_table(urb->sg, urb->num_sgs + 1);
1245 
1246 	sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb));
1247 	total_len += skb_headlen(skb);
1248 
1249 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1250 		struct skb_frag_struct *f = &skb_shinfo(skb)->frags[i];
1251 
1252 		total_len += skb_frag_size(f);
1253 		sg_set_page(&urb->sg[i + s], f->page.p, f->size,
1254 				f->page_offset);
1255 	}
1256 	urb->transfer_buffer_length = total_len;
1257 
1258 	return 1;
1259 }
1260 
1261 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1262 				     struct net_device *net)
1263 {
1264 	struct usbnet		*dev = netdev_priv(net);
1265 	int			length;
1266 	struct urb		*urb = NULL;
1267 	struct skb_data		*entry;
1268 	struct driver_info	*info = dev->driver_info;
1269 	unsigned long		flags;
1270 	int retval;
1271 
1272 	if (skb)
1273 		skb_tx_timestamp(skb);
1274 
1275 	// some devices want funky USB-level framing, for
1276 	// win32 driver (usually) and/or hardware quirks
1277 	if (info->tx_fixup) {
1278 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1279 		if (!skb) {
1280 			/* packet collected; minidriver waiting for more */
1281 			if (info->flags & FLAG_MULTI_PACKET)
1282 				goto not_drop;
1283 			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1284 			goto drop;
1285 		}
1286 	}
1287 
1288 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1289 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1290 		goto drop;
1291 	}
1292 
1293 	entry = (struct skb_data *) skb->cb;
1294 	entry->urb = urb;
1295 	entry->dev = dev;
1296 
1297 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1298 			skb->data, skb->len, tx_complete, skb);
1299 	if (dev->can_dma_sg) {
1300 		if (build_dma_sg(skb, urb) < 0)
1301 			goto drop;
1302 	}
1303 	length = urb->transfer_buffer_length;
1304 
1305 	/* don't assume the hardware handles USB_ZERO_PACKET
1306 	 * NOTE:  strictly conforming cdc-ether devices should expect
1307 	 * the ZLP here, but ignore the one-byte packet.
1308 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1309 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1310 	 * packet itself if needed.
1311 	 */
1312 	if (length % dev->maxpacket == 0) {
1313 		if (!(info->flags & FLAG_SEND_ZLP)) {
1314 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1315 				length++;
1316 				if (skb_tailroom(skb) && !urb->num_sgs) {
1317 					skb->data[skb->len] = 0;
1318 					__skb_put(skb, 1);
1319 				} else if (urb->num_sgs)
1320 					sg_set_buf(&urb->sg[urb->num_sgs++],
1321 							dev->padding_pkt, 1);
1322 			}
1323 		} else
1324 			urb->transfer_flags |= URB_ZERO_PACKET;
1325 	}
1326 	entry->length = urb->transfer_buffer_length = length;
1327 
1328 	spin_lock_irqsave(&dev->txq.lock, flags);
1329 	retval = usb_autopm_get_interface_async(dev->intf);
1330 	if (retval < 0) {
1331 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1332 		goto drop;
1333 	}
1334 
1335 #ifdef CONFIG_PM
1336 	/* if this triggers the device is still a sleep */
1337 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1338 		/* transmission will be done in resume */
1339 		usb_anchor_urb(urb, &dev->deferred);
1340 		/* no use to process more packets */
1341 		netif_stop_queue(net);
1342 		usb_put_urb(urb);
1343 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1344 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1345 		goto deferred;
1346 	}
1347 #endif
1348 
1349 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1350 	case -EPIPE:
1351 		netif_stop_queue (net);
1352 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1353 		usb_autopm_put_interface_async(dev->intf);
1354 		break;
1355 	default:
1356 		usb_autopm_put_interface_async(dev->intf);
1357 		netif_dbg(dev, tx_err, dev->net,
1358 			  "tx: submit urb err %d\n", retval);
1359 		break;
1360 	case 0:
1361 		net->trans_start = jiffies;
1362 		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1363 		if (dev->txq.qlen >= TX_QLEN (dev))
1364 			netif_stop_queue (net);
1365 	}
1366 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1367 
1368 	if (retval) {
1369 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1370 drop:
1371 		dev->net->stats.tx_dropped++;
1372 not_drop:
1373 		if (skb)
1374 			dev_kfree_skb_any (skb);
1375 		if (urb) {
1376 			kfree(urb->sg);
1377 			usb_free_urb(urb);
1378 		}
1379 	} else
1380 		netif_dbg(dev, tx_queued, dev->net,
1381 			  "> tx, len %d, type 0x%x\n", length, skb->protocol);
1382 #ifdef CONFIG_PM
1383 deferred:
1384 #endif
1385 	return NETDEV_TX_OK;
1386 }
1387 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1388 
1389 static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1390 {
1391 	struct urb	*urb;
1392 	int		i;
1393 	int		ret = 0;
1394 
1395 	/* don't refill the queue all at once */
1396 	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1397 		urb = usb_alloc_urb(0, flags);
1398 		if (urb != NULL) {
1399 			ret = rx_submit(dev, urb, flags);
1400 			if (ret)
1401 				goto err;
1402 		} else {
1403 			ret = -ENOMEM;
1404 			goto err;
1405 		}
1406 	}
1407 err:
1408 	return ret;
1409 }
1410 
1411 /*-------------------------------------------------------------------------*/
1412 
1413 // tasklet (work deferred from completions, in_irq) or timer
1414 
1415 static void usbnet_bh (unsigned long param)
1416 {
1417 	struct usbnet		*dev = (struct usbnet *) param;
1418 	struct sk_buff		*skb;
1419 	struct skb_data		*entry;
1420 
1421 	while ((skb = skb_dequeue (&dev->done))) {
1422 		entry = (struct skb_data *) skb->cb;
1423 		switch (entry->state) {
1424 		case rx_done:
1425 			entry->state = rx_cleanup;
1426 			rx_process (dev, skb);
1427 			continue;
1428 		case tx_done:
1429 			kfree(entry->urb->sg);
1430 		case rx_cleanup:
1431 			usb_free_urb (entry->urb);
1432 			dev_kfree_skb (skb);
1433 			continue;
1434 		default:
1435 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1436 		}
1437 	}
1438 
1439 	/* restart RX again after disabling due to high error rate */
1440 	clear_bit(EVENT_RX_KILL, &dev->flags);
1441 
1442 	/* waiting for all pending urbs to complete?
1443 	 * only then can we forgo submitting anew
1444 	 */
1445 	if (waitqueue_active(&dev->wait)) {
1446 		if (dev->txq.qlen + dev->rxq.qlen + dev->done.qlen == 0)
1447 			wake_up_all(&dev->wait);
1448 
1449 	// or are we maybe short a few urbs?
1450 	} else if (netif_running (dev->net) &&
1451 		   netif_device_present (dev->net) &&
1452 		   netif_carrier_ok(dev->net) &&
1453 		   !timer_pending (&dev->delay) &&
1454 		   !test_bit (EVENT_RX_HALT, &dev->flags)) {
1455 		int	temp = dev->rxq.qlen;
1456 
1457 		if (temp < RX_QLEN(dev)) {
1458 			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1459 				return;
1460 			if (temp != dev->rxq.qlen)
1461 				netif_dbg(dev, link, dev->net,
1462 					  "rxqlen %d --> %d\n",
1463 					  temp, dev->rxq.qlen);
1464 			if (dev->rxq.qlen < RX_QLEN(dev))
1465 				tasklet_schedule (&dev->bh);
1466 		}
1467 		if (dev->txq.qlen < TX_QLEN (dev))
1468 			netif_wake_queue (dev->net);
1469 	}
1470 }
1471 
1472 
1473 /*-------------------------------------------------------------------------
1474  *
1475  * USB Device Driver support
1476  *
1477  *-------------------------------------------------------------------------*/
1478 
1479 // precondition: never called in_interrupt
1480 
1481 void usbnet_disconnect (struct usb_interface *intf)
1482 {
1483 	struct usbnet		*dev;
1484 	struct usb_device	*xdev;
1485 	struct net_device	*net;
1486 
1487 	dev = usb_get_intfdata(intf);
1488 	usb_set_intfdata(intf, NULL);
1489 	if (!dev)
1490 		return;
1491 
1492 	xdev = interface_to_usbdev (intf);
1493 
1494 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1495 		   intf->dev.driver->name,
1496 		   xdev->bus->bus_name, xdev->devpath,
1497 		   dev->driver_info->description);
1498 
1499 	net = dev->net;
1500 	unregister_netdev (net);
1501 
1502 	cancel_work_sync(&dev->kevent);
1503 
1504 	usb_scuttle_anchored_urbs(&dev->deferred);
1505 
1506 	if (dev->driver_info->unbind)
1507 		dev->driver_info->unbind (dev, intf);
1508 
1509 	usb_kill_urb(dev->interrupt);
1510 	usb_free_urb(dev->interrupt);
1511 	kfree(dev->padding_pkt);
1512 
1513 	free_netdev(net);
1514 }
1515 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1516 
1517 static const struct net_device_ops usbnet_netdev_ops = {
1518 	.ndo_open		= usbnet_open,
1519 	.ndo_stop		= usbnet_stop,
1520 	.ndo_start_xmit		= usbnet_start_xmit,
1521 	.ndo_tx_timeout		= usbnet_tx_timeout,
1522 	.ndo_change_mtu		= usbnet_change_mtu,
1523 	.ndo_set_mac_address 	= eth_mac_addr,
1524 	.ndo_validate_addr	= eth_validate_addr,
1525 };
1526 
1527 /*-------------------------------------------------------------------------*/
1528 
1529 // precondition: never called in_interrupt
1530 
1531 static struct device_type wlan_type = {
1532 	.name	= "wlan",
1533 };
1534 
1535 static struct device_type wwan_type = {
1536 	.name	= "wwan",
1537 };
1538 
1539 int
1540 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1541 {
1542 	struct usbnet			*dev;
1543 	struct net_device		*net;
1544 	struct usb_host_interface	*interface;
1545 	struct driver_info		*info;
1546 	struct usb_device		*xdev;
1547 	int				status;
1548 	const char			*name;
1549 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1550 
1551 	/* usbnet already took usb runtime pm, so have to enable the feature
1552 	 * for usb interface, otherwise usb_autopm_get_interface may return
1553 	 * failure if RUNTIME_PM is enabled.
1554 	 */
1555 	if (!driver->supports_autosuspend) {
1556 		driver->supports_autosuspend = 1;
1557 		pm_runtime_enable(&udev->dev);
1558 	}
1559 
1560 	name = udev->dev.driver->name;
1561 	info = (struct driver_info *) prod->driver_info;
1562 	if (!info) {
1563 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1564 		return -ENODEV;
1565 	}
1566 	xdev = interface_to_usbdev (udev);
1567 	interface = udev->cur_altsetting;
1568 
1569 	status = -ENOMEM;
1570 
1571 	// set up our own records
1572 	net = alloc_etherdev(sizeof(*dev));
1573 	if (!net)
1574 		goto out;
1575 
1576 	/* netdev_printk() needs this so do it as early as possible */
1577 	SET_NETDEV_DEV(net, &udev->dev);
1578 
1579 	dev = netdev_priv(net);
1580 	dev->udev = xdev;
1581 	dev->intf = udev;
1582 	dev->driver_info = info;
1583 	dev->driver_name = name;
1584 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1585 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1586 	init_waitqueue_head(&dev->wait);
1587 	skb_queue_head_init (&dev->rxq);
1588 	skb_queue_head_init (&dev->txq);
1589 	skb_queue_head_init (&dev->done);
1590 	skb_queue_head_init(&dev->rxq_pause);
1591 	dev->bh.func = usbnet_bh;
1592 	dev->bh.data = (unsigned long) dev;
1593 	INIT_WORK (&dev->kevent, kevent);
1594 	init_usb_anchor(&dev->deferred);
1595 	dev->delay.function = usbnet_bh;
1596 	dev->delay.data = (unsigned long) dev;
1597 	init_timer (&dev->delay);
1598 	mutex_init (&dev->phy_mutex);
1599 	mutex_init(&dev->interrupt_mutex);
1600 	dev->interrupt_count = 0;
1601 
1602 	dev->net = net;
1603 	strcpy (net->name, "usb%d");
1604 	memcpy (net->dev_addr, node_id, sizeof node_id);
1605 
1606 	/* rx and tx sides can use different message sizes;
1607 	 * bind() should set rx_urb_size in that case.
1608 	 */
1609 	dev->hard_mtu = net->mtu + net->hard_header_len;
1610 #if 0
1611 // dma_supported() is deeply broken on almost all architectures
1612 	// possible with some EHCI controllers
1613 	if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1614 		net->features |= NETIF_F_HIGHDMA;
1615 #endif
1616 
1617 	net->netdev_ops = &usbnet_netdev_ops;
1618 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1619 	net->ethtool_ops = &usbnet_ethtool_ops;
1620 
1621 	// allow device-specific bind/init procedures
1622 	// NOTE net->name still not usable ...
1623 	if (info->bind) {
1624 		status = info->bind (dev, udev);
1625 		if (status < 0)
1626 			goto out1;
1627 
1628 		// heuristic:  "usb%d" for links we know are two-host,
1629 		// else "eth%d" when there's reasonable doubt.  userspace
1630 		// can rename the link if it knows better.
1631 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1632 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1633 		     (net->dev_addr [0] & 0x02) == 0))
1634 			strcpy (net->name, "eth%d");
1635 		/* WLAN devices should always be named "wlan%d" */
1636 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1637 			strcpy(net->name, "wlan%d");
1638 		/* WWAN devices should always be named "wwan%d" */
1639 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1640 			strcpy(net->name, "wwan%d");
1641 
1642 		/* devices that cannot do ARP */
1643 		if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1644 			net->flags |= IFF_NOARP;
1645 
1646 		/* maybe the remote can't receive an Ethernet MTU */
1647 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1648 			net->mtu = dev->hard_mtu - net->hard_header_len;
1649 	} else if (!info->in || !info->out)
1650 		status = usbnet_get_endpoints (dev, udev);
1651 	else {
1652 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1653 		dev->out = usb_sndbulkpipe (xdev, info->out);
1654 		if (!(info->flags & FLAG_NO_SETINT))
1655 			status = usb_set_interface (xdev,
1656 				interface->desc.bInterfaceNumber,
1657 				interface->desc.bAlternateSetting);
1658 		else
1659 			status = 0;
1660 
1661 	}
1662 	if (status >= 0 && dev->status)
1663 		status = init_status (dev, udev);
1664 	if (status < 0)
1665 		goto out3;
1666 
1667 	if (!dev->rx_urb_size)
1668 		dev->rx_urb_size = dev->hard_mtu;
1669 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1670 
1671 	/* let userspace know we have a random address */
1672 	if (ether_addr_equal(net->dev_addr, node_id))
1673 		net->addr_assign_type = NET_ADDR_RANDOM;
1674 
1675 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1676 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1677 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1678 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1679 
1680 	/* initialize max rx_qlen and tx_qlen */
1681 	usbnet_update_max_qlen(dev);
1682 
1683 	if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&
1684 		!(info->flags & FLAG_MULTI_PACKET)) {
1685 		dev->padding_pkt = kzalloc(1, GFP_KERNEL);
1686 		if (!dev->padding_pkt) {
1687 			status = -ENOMEM;
1688 			goto out4;
1689 		}
1690 	}
1691 
1692 	status = register_netdev (net);
1693 	if (status)
1694 		goto out5;
1695 	netif_info(dev, probe, dev->net,
1696 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1697 		   udev->dev.driver->name,
1698 		   xdev->bus->bus_name, xdev->devpath,
1699 		   dev->driver_info->description,
1700 		   net->dev_addr);
1701 
1702 	// ok, it's ready to go.
1703 	usb_set_intfdata (udev, dev);
1704 
1705 	netif_device_attach (net);
1706 
1707 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1708 		usbnet_link_change(dev, 0, 0);
1709 
1710 	return 0;
1711 
1712 out5:
1713 	kfree(dev->padding_pkt);
1714 out4:
1715 	usb_free_urb(dev->interrupt);
1716 out3:
1717 	if (info->unbind)
1718 		info->unbind (dev, udev);
1719 out1:
1720 	free_netdev(net);
1721 out:
1722 	return status;
1723 }
1724 EXPORT_SYMBOL_GPL(usbnet_probe);
1725 
1726 /*-------------------------------------------------------------------------*/
1727 
1728 /*
1729  * suspend the whole driver as soon as the first interface is suspended
1730  * resume only when the last interface is resumed
1731  */
1732 
1733 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1734 {
1735 	struct usbnet		*dev = usb_get_intfdata(intf);
1736 
1737 	if (!dev->suspend_count++) {
1738 		spin_lock_irq(&dev->txq.lock);
1739 		/* don't autosuspend while transmitting */
1740 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1741 			dev->suspend_count--;
1742 			spin_unlock_irq(&dev->txq.lock);
1743 			return -EBUSY;
1744 		} else {
1745 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1746 			spin_unlock_irq(&dev->txq.lock);
1747 		}
1748 		/*
1749 		 * accelerate emptying of the rx and queues, to avoid
1750 		 * having everything error out.
1751 		 */
1752 		netif_device_detach (dev->net);
1753 		usbnet_terminate_urbs(dev);
1754 		__usbnet_status_stop_force(dev);
1755 
1756 		/*
1757 		 * reattach so runtime management can use and
1758 		 * wake the device
1759 		 */
1760 		netif_device_attach (dev->net);
1761 	}
1762 	return 0;
1763 }
1764 EXPORT_SYMBOL_GPL(usbnet_suspend);
1765 
1766 int usbnet_resume (struct usb_interface *intf)
1767 {
1768 	struct usbnet		*dev = usb_get_intfdata(intf);
1769 	struct sk_buff          *skb;
1770 	struct urb              *res;
1771 	int                     retval;
1772 
1773 	if (!--dev->suspend_count) {
1774 		/* resume interrupt URB if it was previously submitted */
1775 		__usbnet_status_start_force(dev, GFP_NOIO);
1776 
1777 		spin_lock_irq(&dev->txq.lock);
1778 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1779 
1780 			skb = (struct sk_buff *)res->context;
1781 			retval = usb_submit_urb(res, GFP_ATOMIC);
1782 			if (retval < 0) {
1783 				dev_kfree_skb_any(skb);
1784 				kfree(res->sg);
1785 				usb_free_urb(res);
1786 				usb_autopm_put_interface_async(dev->intf);
1787 			} else {
1788 				dev->net->trans_start = jiffies;
1789 				__skb_queue_tail(&dev->txq, skb);
1790 			}
1791 		}
1792 
1793 		smp_mb();
1794 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1795 		spin_unlock_irq(&dev->txq.lock);
1796 
1797 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1798 			/* handle remote wakeup ASAP
1799 			 * we cannot race against stop
1800 			 */
1801 			if (netif_device_present(dev->net) &&
1802 				!timer_pending(&dev->delay) &&
1803 				!test_bit(EVENT_RX_HALT, &dev->flags))
1804 					rx_alloc_submit(dev, GFP_NOIO);
1805 
1806 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1807 				netif_tx_wake_all_queues(dev->net);
1808 			tasklet_schedule (&dev->bh);
1809 		}
1810 	}
1811 
1812 	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1813 		usb_autopm_get_interface_no_resume(intf);
1814 
1815 	return 0;
1816 }
1817 EXPORT_SYMBOL_GPL(usbnet_resume);
1818 
1819 /*
1820  * Either a subdriver implements manage_power, then it is assumed to always
1821  * be ready to be suspended or it reports the readiness to be suspended
1822  * explicitly
1823  */
1824 void usbnet_device_suggests_idle(struct usbnet *dev)
1825 {
1826 	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1827 		dev->intf->needs_remote_wakeup = 1;
1828 		usb_autopm_put_interface_async(dev->intf);
1829 	}
1830 }
1831 EXPORT_SYMBOL(usbnet_device_suggests_idle);
1832 
1833 /*
1834  * For devices that can do without special commands
1835  */
1836 int usbnet_manage_power(struct usbnet *dev, int on)
1837 {
1838 	dev->intf->needs_remote_wakeup = on;
1839 	return 0;
1840 }
1841 EXPORT_SYMBOL(usbnet_manage_power);
1842 
1843 void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
1844 {
1845 	/* update link after link is reseted */
1846 	if (link && !need_reset)
1847 		netif_carrier_on(dev->net);
1848 	else
1849 		netif_carrier_off(dev->net);
1850 
1851 	if (need_reset && link)
1852 		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
1853 	else
1854 		usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
1855 }
1856 EXPORT_SYMBOL(usbnet_link_change);
1857 
1858 /*-------------------------------------------------------------------------*/
1859 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1860 			     u16 value, u16 index, void *data, u16 size)
1861 {
1862 	void *buf = NULL;
1863 	int err = -ENOMEM;
1864 
1865 	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
1866 		   " value=0x%04x index=0x%04x size=%d\n",
1867 		   cmd, reqtype, value, index, size);
1868 
1869 	if (data) {
1870 		buf = kmalloc(size, GFP_KERNEL);
1871 		if (!buf)
1872 			goto out;
1873 	}
1874 
1875 	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
1876 			      cmd, reqtype, value, index, buf, size,
1877 			      USB_CTRL_GET_TIMEOUT);
1878 	if (err > 0 && err <= size)
1879 		memcpy(data, buf, err);
1880 	kfree(buf);
1881 out:
1882 	return err;
1883 }
1884 
1885 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1886 			      u16 value, u16 index, const void *data,
1887 			      u16 size)
1888 {
1889 	void *buf = NULL;
1890 	int err = -ENOMEM;
1891 
1892 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
1893 		   " value=0x%04x index=0x%04x size=%d\n",
1894 		   cmd, reqtype, value, index, size);
1895 
1896 	if (data) {
1897 		buf = kmemdup(data, size, GFP_KERNEL);
1898 		if (!buf)
1899 			goto out;
1900 	}
1901 
1902 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
1903 			      cmd, reqtype, value, index, buf, size,
1904 			      USB_CTRL_SET_TIMEOUT);
1905 	kfree(buf);
1906 
1907 out:
1908 	return err;
1909 }
1910 
1911 /*
1912  * The function can't be called inside suspend/resume callback,
1913  * otherwise deadlock will be caused.
1914  */
1915 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1916 		    u16 value, u16 index, void *data, u16 size)
1917 {
1918 	int ret;
1919 
1920 	if (usb_autopm_get_interface(dev->intf) < 0)
1921 		return -ENODEV;
1922 	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
1923 				data, size);
1924 	usb_autopm_put_interface(dev->intf);
1925 	return ret;
1926 }
1927 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
1928 
1929 /*
1930  * The function can't be called inside suspend/resume callback,
1931  * otherwise deadlock will be caused.
1932  */
1933 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1934 		     u16 value, u16 index, const void *data, u16 size)
1935 {
1936 	int ret;
1937 
1938 	if (usb_autopm_get_interface(dev->intf) < 0)
1939 		return -ENODEV;
1940 	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
1941 				 data, size);
1942 	usb_autopm_put_interface(dev->intf);
1943 	return ret;
1944 }
1945 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
1946 
1947 /*
1948  * The function can be called inside suspend/resume callback safely
1949  * and should only be called by suspend/resume callback generally.
1950  */
1951 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
1952 			  u16 value, u16 index, void *data, u16 size)
1953 {
1954 	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
1955 				 data, size);
1956 }
1957 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
1958 
1959 /*
1960  * The function can be called inside suspend/resume callback safely
1961  * and should only be called by suspend/resume callback generally.
1962  */
1963 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
1964 			  u16 value, u16 index, const void *data,
1965 			  u16 size)
1966 {
1967 	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
1968 				  data, size);
1969 }
1970 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
1971 
1972 static void usbnet_async_cmd_cb(struct urb *urb)
1973 {
1974 	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
1975 	int status = urb->status;
1976 
1977 	if (status < 0)
1978 		dev_dbg(&urb->dev->dev, "%s failed with %d",
1979 			__func__, status);
1980 
1981 	kfree(req);
1982 	usb_free_urb(urb);
1983 }
1984 
1985 /*
1986  * The caller must make sure that device can't be put into suspend
1987  * state until the control URB completes.
1988  */
1989 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
1990 			   u16 value, u16 index, const void *data, u16 size)
1991 {
1992 	struct usb_ctrlrequest *req = NULL;
1993 	struct urb *urb;
1994 	int err = -ENOMEM;
1995 	void *buf = NULL;
1996 
1997 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
1998 		   " value=0x%04x index=0x%04x size=%d\n",
1999 		   cmd, reqtype, value, index, size);
2000 
2001 	urb = usb_alloc_urb(0, GFP_ATOMIC);
2002 	if (!urb) {
2003 		netdev_err(dev->net, "Error allocating URB in"
2004 			   " %s!\n", __func__);
2005 		goto fail;
2006 	}
2007 
2008 	if (data) {
2009 		buf = kmemdup(data, size, GFP_ATOMIC);
2010 		if (!buf) {
2011 			netdev_err(dev->net, "Error allocating buffer"
2012 				   " in %s!\n", __func__);
2013 			goto fail_free;
2014 		}
2015 	}
2016 
2017 	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
2018 	if (!req)
2019 		goto fail_free_buf;
2020 
2021 	req->bRequestType = reqtype;
2022 	req->bRequest = cmd;
2023 	req->wValue = cpu_to_le16(value);
2024 	req->wIndex = cpu_to_le16(index);
2025 	req->wLength = cpu_to_le16(size);
2026 
2027 	usb_fill_control_urb(urb, dev->udev,
2028 			     usb_sndctrlpipe(dev->udev, 0),
2029 			     (void *)req, buf, size,
2030 			     usbnet_async_cmd_cb, req);
2031 	urb->transfer_flags |= URB_FREE_BUFFER;
2032 
2033 	err = usb_submit_urb(urb, GFP_ATOMIC);
2034 	if (err < 0) {
2035 		netdev_err(dev->net, "Error submitting the control"
2036 			   " message: status=%d\n", err);
2037 		goto fail_free;
2038 	}
2039 	return 0;
2040 
2041 fail_free_buf:
2042 	kfree(buf);
2043 fail_free:
2044 	kfree(req);
2045 	usb_free_urb(urb);
2046 fail:
2047 	return err;
2048 
2049 }
2050 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
2051 /*-------------------------------------------------------------------------*/
2052 
2053 static int __init usbnet_init(void)
2054 {
2055 	/* Compiler should optimize this out. */
2056 	BUILD_BUG_ON(
2057 		FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
2058 
2059 	eth_random_addr(node_id);
2060 	return 0;
2061 }
2062 module_init(usbnet_init);
2063 
2064 static void __exit usbnet_exit(void)
2065 {
2066 }
2067 module_exit(usbnet_exit);
2068 
2069 MODULE_AUTHOR("David Brownell");
2070 MODULE_DESCRIPTION("USB network driver framework");
2071 MODULE_LICENSE("GPL");
2072