xref: /linux/drivers/net/usb/usbnet.c (revision 93d90ad708b8da6efc0e487b66111aa9db7f70c7)
1 /*
2  * USB Network driver infrastructure
3  * Copyright (C) 2000-2005 by David Brownell
4  * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 /*
21  * This is a generic "USB networking" framework that works with several
22  * kinds of full and high speed networking devices:  host-to-host cables,
23  * smart usb peripherals, and actual Ethernet adapters.
24  *
25  * These devices usually differ in terms of control protocols (if they
26  * even have one!) and sometimes they define new framing to wrap or batch
27  * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
28  * so interface (un)binding, endpoint I/O queues, fault handling, and other
29  * issues can usefully be addressed by this framework.
30  */
31 
32 // #define	DEBUG			// error path messages, extra info
33 // #define	VERBOSE			// more; success messages
34 
35 #include <linux/module.h>
36 #include <linux/init.h>
37 #include <linux/netdevice.h>
38 #include <linux/etherdevice.h>
39 #include <linux/ctype.h>
40 #include <linux/ethtool.h>
41 #include <linux/workqueue.h>
42 #include <linux/mii.h>
43 #include <linux/usb.h>
44 #include <linux/usb/usbnet.h>
45 #include <linux/slab.h>
46 #include <linux/kernel.h>
47 #include <linux/pm_runtime.h>
48 
49 #define DRIVER_VERSION		"22-Aug-2005"
50 
51 
52 /*-------------------------------------------------------------------------*/
53 
54 /*
55  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
56  * Several dozen bytes of IPv4 data can fit in two such transactions.
57  * One maximum size Ethernet packet takes twenty four of them.
58  * For high speed, each frame comfortably fits almost 36 max size
59  * Ethernet packets (so queues should be bigger).
60  *
61  * The goal is to let the USB host controller be busy for 5msec or
62  * more before an irq is required, under load.  Jumbograms change
63  * the equation.
64  */
65 #define	MAX_QUEUE_MEMORY	(60 * 1518)
66 #define	RX_QLEN(dev)		((dev)->rx_qlen)
67 #define	TX_QLEN(dev)		((dev)->tx_qlen)
68 
69 // reawaken network queue this soon after stopping; else watchdog barks
70 #define TX_TIMEOUT_JIFFIES	(5*HZ)
71 
72 /* throttle rx/tx briefly after some faults, so hub_wq might disconnect()
73  * us (it polls at HZ/4 usually) before we report too many false errors.
74  */
75 #define THROTTLE_JIFFIES	(HZ/8)
76 
77 // between wakeups
78 #define UNLINK_TIMEOUT_MS	3
79 
80 /*-------------------------------------------------------------------------*/
81 
82 // randomly generated ethernet address
83 static u8	node_id [ETH_ALEN];
84 
85 static const char driver_name [] = "usbnet";
86 
87 /* use ethtool to change the level for any given device */
88 static int msg_level = -1;
89 module_param (msg_level, int, 0);
90 MODULE_PARM_DESC (msg_level, "Override default message level");
91 
92 /*-------------------------------------------------------------------------*/
93 
94 /* handles CDC Ethernet and many other network "bulk data" interfaces */
95 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
96 {
97 	int				tmp;
98 	struct usb_host_interface	*alt = NULL;
99 	struct usb_host_endpoint	*in = NULL, *out = NULL;
100 	struct usb_host_endpoint	*status = NULL;
101 
102 	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
103 		unsigned	ep;
104 
105 		in = out = status = NULL;
106 		alt = intf->altsetting + tmp;
107 
108 		/* take the first altsetting with in-bulk + out-bulk;
109 		 * remember any status endpoint, just in case;
110 		 * ignore other endpoints and altsettings.
111 		 */
112 		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
113 			struct usb_host_endpoint	*e;
114 			int				intr = 0;
115 
116 			e = alt->endpoint + ep;
117 			switch (e->desc.bmAttributes) {
118 			case USB_ENDPOINT_XFER_INT:
119 				if (!usb_endpoint_dir_in(&e->desc))
120 					continue;
121 				intr = 1;
122 				/* FALLTHROUGH */
123 			case USB_ENDPOINT_XFER_BULK:
124 				break;
125 			default:
126 				continue;
127 			}
128 			if (usb_endpoint_dir_in(&e->desc)) {
129 				if (!intr && !in)
130 					in = e;
131 				else if (intr && !status)
132 					status = e;
133 			} else {
134 				if (!out)
135 					out = e;
136 			}
137 		}
138 		if (in && out)
139 			break;
140 	}
141 	if (!alt || !in || !out)
142 		return -EINVAL;
143 
144 	if (alt->desc.bAlternateSetting != 0 ||
145 	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
146 		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
147 				alt->desc.bAlternateSetting);
148 		if (tmp < 0)
149 			return tmp;
150 	}
151 
152 	dev->in = usb_rcvbulkpipe (dev->udev,
153 			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
154 	dev->out = usb_sndbulkpipe (dev->udev,
155 			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
156 	dev->status = status;
157 	return 0;
158 }
159 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
160 
161 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
162 {
163 	int 		tmp, 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 	status = usb_submit_urb (urb, GFP_ATOMIC);
208 	if (status != 0)
209 		netif_err(dev, timer, dev->net,
210 			  "intr resubmit --> %d\n", status);
211 }
212 
213 static int init_status (struct usbnet *dev, struct usb_interface *intf)
214 {
215 	char		*buf = NULL;
216 	unsigned	pipe = 0;
217 	unsigned	maxp;
218 	unsigned	period;
219 
220 	if (!dev->driver_info->status)
221 		return 0;
222 
223 	pipe = usb_rcvintpipe (dev->udev,
224 			dev->status->desc.bEndpointAddress
225 				& USB_ENDPOINT_NUMBER_MASK);
226 	maxp = usb_maxpacket (dev->udev, pipe, 0);
227 
228 	/* avoid 1 msec chatter:  min 8 msec poll rate */
229 	period = max ((int) dev->status->desc.bInterval,
230 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
231 
232 	buf = kmalloc (maxp, GFP_KERNEL);
233 	if (buf) {
234 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
235 		if (!dev->interrupt) {
236 			kfree (buf);
237 			return -ENOMEM;
238 		} else {
239 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
240 				buf, maxp, intr_complete, dev, period);
241 			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
242 			dev_dbg(&intf->dev,
243 				"status ep%din, %d bytes period %d\n",
244 				usb_pipeendpoint(pipe), maxp, period);
245 		}
246 	}
247 	return 0;
248 }
249 
250 /* Submit the interrupt URB if not previously submitted, increasing refcount */
251 int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
252 {
253 	int ret = 0;
254 
255 	WARN_ON_ONCE(dev->interrupt == NULL);
256 	if (dev->interrupt) {
257 		mutex_lock(&dev->interrupt_mutex);
258 
259 		if (++dev->interrupt_count == 1)
260 			ret = usb_submit_urb(dev->interrupt, mem_flags);
261 
262 		dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
263 			dev->interrupt_count);
264 		mutex_unlock(&dev->interrupt_mutex);
265 	}
266 	return ret;
267 }
268 EXPORT_SYMBOL_GPL(usbnet_status_start);
269 
270 /* For resume; submit interrupt URB if previously submitted */
271 static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
272 {
273 	int ret = 0;
274 
275 	mutex_lock(&dev->interrupt_mutex);
276 	if (dev->interrupt_count) {
277 		ret = usb_submit_urb(dev->interrupt, mem_flags);
278 		dev_dbg(&dev->udev->dev,
279 			"submitted interrupt URB for resume\n");
280 	}
281 	mutex_unlock(&dev->interrupt_mutex);
282 	return ret;
283 }
284 
285 /* Kill the interrupt URB if all submitters want it killed */
286 void usbnet_status_stop(struct usbnet *dev)
287 {
288 	if (dev->interrupt) {
289 		mutex_lock(&dev->interrupt_mutex);
290 		WARN_ON(dev->interrupt_count == 0);
291 
292 		if (dev->interrupt_count && --dev->interrupt_count == 0)
293 			usb_kill_urb(dev->interrupt);
294 
295 		dev_dbg(&dev->udev->dev,
296 			"decremented interrupt URB count to %d\n",
297 			dev->interrupt_count);
298 		mutex_unlock(&dev->interrupt_mutex);
299 	}
300 }
301 EXPORT_SYMBOL_GPL(usbnet_status_stop);
302 
303 /* For suspend; always kill interrupt URB */
304 static void __usbnet_status_stop_force(struct usbnet *dev)
305 {
306 	if (dev->interrupt) {
307 		mutex_lock(&dev->interrupt_mutex);
308 		usb_kill_urb(dev->interrupt);
309 		dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
310 		mutex_unlock(&dev->interrupt_mutex);
311 	}
312 }
313 
314 /* Passes this packet up the stack, updating its accounting.
315  * Some link protocols batch packets, so their rx_fixup paths
316  * can return clones as well as just modify the original skb.
317  */
318 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
319 {
320 	int	status;
321 
322 	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
323 		skb_queue_tail(&dev->rxq_pause, skb);
324 		return;
325 	}
326 
327 	skb->protocol = eth_type_trans (skb, dev->net);
328 	dev->net->stats.rx_packets++;
329 	dev->net->stats.rx_bytes += skb->len;
330 
331 	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
332 		  skb->len + sizeof (struct ethhdr), skb->protocol);
333 	memset (skb->cb, 0, sizeof (struct skb_data));
334 
335 	if (skb_defer_rx_timestamp(skb))
336 		return;
337 
338 	status = netif_rx (skb);
339 	if (status != NET_RX_SUCCESS)
340 		netif_dbg(dev, rx_err, dev->net,
341 			  "netif_rx status %d\n", status);
342 }
343 EXPORT_SYMBOL_GPL(usbnet_skb_return);
344 
345 /* must be called if hard_mtu or rx_urb_size changed */
346 void usbnet_update_max_qlen(struct usbnet *dev)
347 {
348 	enum usb_device_speed speed = dev->udev->speed;
349 
350 	switch (speed) {
351 	case USB_SPEED_HIGH:
352 		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
353 		dev->tx_qlen = MAX_QUEUE_MEMORY / dev->hard_mtu;
354 		break;
355 	case USB_SPEED_SUPER:
356 		/*
357 		 * Not take default 5ms qlen for super speed HC to
358 		 * save memory, and iperf tests show 2.5ms qlen can
359 		 * work well
360 		 */
361 		dev->rx_qlen = 5 * MAX_QUEUE_MEMORY / dev->rx_urb_size;
362 		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
363 		break;
364 	default:
365 		dev->rx_qlen = dev->tx_qlen = 4;
366 	}
367 }
368 EXPORT_SYMBOL_GPL(usbnet_update_max_qlen);
369 
370 
371 /*-------------------------------------------------------------------------
372  *
373  * Network Device Driver (peer link to "Host Device", from USB host)
374  *
375  *-------------------------------------------------------------------------*/
376 
377 int usbnet_change_mtu (struct net_device *net, int new_mtu)
378 {
379 	struct usbnet	*dev = netdev_priv(net);
380 	int		ll_mtu = new_mtu + net->hard_header_len;
381 	int		old_hard_mtu = dev->hard_mtu;
382 	int		old_rx_urb_size = dev->rx_urb_size;
383 
384 	if (new_mtu <= 0)
385 		return -EINVAL;
386 	// no second zero-length packet read wanted after mtu-sized packets
387 	if ((ll_mtu % dev->maxpacket) == 0)
388 		return -EDOM;
389 	net->mtu = new_mtu;
390 
391 	dev->hard_mtu = net->mtu + net->hard_header_len;
392 	if (dev->rx_urb_size == old_hard_mtu) {
393 		dev->rx_urb_size = dev->hard_mtu;
394 		if (dev->rx_urb_size > old_rx_urb_size)
395 			usbnet_unlink_rx_urbs(dev);
396 	}
397 
398 	/* max qlen depend on hard_mtu and rx_urb_size */
399 	usbnet_update_max_qlen(dev);
400 
401 	return 0;
402 }
403 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
404 
405 /* The caller must hold list->lock */
406 static void __usbnet_queue_skb(struct sk_buff_head *list,
407 			struct sk_buff *newsk, enum skb_state state)
408 {
409 	struct skb_data *entry = (struct skb_data *) newsk->cb;
410 
411 	__skb_queue_tail(list, newsk);
412 	entry->state = state;
413 }
414 
415 /*-------------------------------------------------------------------------*/
416 
417 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
418  * completion callbacks.  2.5 should have fixed those bugs...
419  */
420 
421 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
422 		struct sk_buff_head *list, enum skb_state state)
423 {
424 	unsigned long		flags;
425 	enum skb_state 		old_state;
426 	struct skb_data *entry = (struct skb_data *) skb->cb;
427 
428 	spin_lock_irqsave(&list->lock, flags);
429 	old_state = entry->state;
430 	entry->state = state;
431 	__skb_unlink(skb, list);
432 	spin_unlock(&list->lock);
433 	spin_lock(&dev->done.lock);
434 	__skb_queue_tail(&dev->done, skb);
435 	if (dev->done.qlen == 1)
436 		tasklet_schedule(&dev->bh);
437 	spin_unlock_irqrestore(&dev->done.lock, flags);
438 	return old_state;
439 }
440 
441 /* some work can't be done in tasklets, so we use keventd
442  *
443  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
444  * but tasklet_schedule() doesn't.  hope the failure is rare.
445  */
446 void usbnet_defer_kevent (struct usbnet *dev, int work)
447 {
448 	set_bit (work, &dev->flags);
449 	if (!schedule_work (&dev->kevent)) {
450 		if (net_ratelimit())
451 			netdev_err(dev->net, "kevent %d may have been dropped\n", work);
452 	} else {
453 		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
454 	}
455 }
456 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
457 
458 /*-------------------------------------------------------------------------*/
459 
460 static void rx_complete (struct urb *urb);
461 
462 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
463 {
464 	struct sk_buff		*skb;
465 	struct skb_data		*entry;
466 	int			retval = 0;
467 	unsigned long		lockflags;
468 	size_t			size = dev->rx_urb_size;
469 
470 	/* prevent rx skb allocation when error ratio is high */
471 	if (test_bit(EVENT_RX_KILL, &dev->flags)) {
472 		usb_free_urb(urb);
473 		return -ENOLINK;
474 	}
475 
476 	skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
477 	if (!skb) {
478 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
479 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
480 		usb_free_urb (urb);
481 		return -ENOMEM;
482 	}
483 
484 	entry = (struct skb_data *) skb->cb;
485 	entry->urb = urb;
486 	entry->dev = dev;
487 	entry->length = 0;
488 
489 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
490 		skb->data, size, rx_complete, skb);
491 
492 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
493 
494 	if (netif_running (dev->net) &&
495 	    netif_device_present (dev->net) &&
496 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
497 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
498 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
499 		case -EPIPE:
500 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
501 			break;
502 		case -ENOMEM:
503 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
504 			break;
505 		case -ENODEV:
506 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
507 			netif_device_detach (dev->net);
508 			break;
509 		case -EHOSTUNREACH:
510 			retval = -ENOLINK;
511 			break;
512 		default:
513 			netif_dbg(dev, rx_err, dev->net,
514 				  "rx submit, %d\n", retval);
515 			tasklet_schedule (&dev->bh);
516 			break;
517 		case 0:
518 			__usbnet_queue_skb(&dev->rxq, skb, rx_start);
519 		}
520 	} else {
521 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
522 		retval = -ENOLINK;
523 	}
524 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
525 	if (retval) {
526 		dev_kfree_skb_any (skb);
527 		usb_free_urb (urb);
528 	}
529 	return retval;
530 }
531 
532 
533 /*-------------------------------------------------------------------------*/
534 
535 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
536 {
537 	if (dev->driver_info->rx_fixup &&
538 	    !dev->driver_info->rx_fixup (dev, skb)) {
539 		/* With RX_ASSEMBLE, rx_fixup() must update counters */
540 		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
541 			dev->net->stats.rx_errors++;
542 		goto done;
543 	}
544 	// else network stack removes extra byte if we forced a short packet
545 
546 	/* all data was already cloned from skb inside the driver */
547 	if (dev->driver_info->flags & FLAG_MULTI_PACKET)
548 		goto done;
549 
550 	if (skb->len < ETH_HLEN) {
551 		dev->net->stats.rx_errors++;
552 		dev->net->stats.rx_length_errors++;
553 		netif_dbg(dev, rx_err, dev->net, "rx length %d\n", skb->len);
554 	} else {
555 		usbnet_skb_return(dev, skb);
556 		return;
557 	}
558 
559 done:
560 	skb_queue_tail(&dev->done, skb);
561 }
562 
563 /*-------------------------------------------------------------------------*/
564 
565 static void rx_complete (struct urb *urb)
566 {
567 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
568 	struct skb_data		*entry = (struct skb_data *) skb->cb;
569 	struct usbnet		*dev = entry->dev;
570 	int			urb_status = urb->status;
571 	enum skb_state		state;
572 
573 	skb_put (skb, urb->actual_length);
574 	state = rx_done;
575 	entry->urb = NULL;
576 
577 	switch (urb_status) {
578 	/* success */
579 	case 0:
580 		break;
581 
582 	/* stalls need manual reset. this is rare ... except that
583 	 * when going through USB 2.0 TTs, unplug appears this way.
584 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
585 	 * storm, recovering as needed.
586 	 */
587 	case -EPIPE:
588 		dev->net->stats.rx_errors++;
589 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
590 		// FALLTHROUGH
591 
592 	/* software-driven interface shutdown */
593 	case -ECONNRESET:		/* async unlink */
594 	case -ESHUTDOWN:		/* hardware gone */
595 		netif_dbg(dev, ifdown, dev->net,
596 			  "rx shutdown, code %d\n", urb_status);
597 		goto block;
598 
599 	/* we get controller i/o faults during hub_wq disconnect() delays.
600 	 * throttle down resubmits, to avoid log floods; just temporarily,
601 	 * so we still recover when the fault isn't a hub_wq delay.
602 	 */
603 	case -EPROTO:
604 	case -ETIME:
605 	case -EILSEQ:
606 		dev->net->stats.rx_errors++;
607 		if (!timer_pending (&dev->delay)) {
608 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
609 			netif_dbg(dev, link, dev->net,
610 				  "rx throttle %d\n", urb_status);
611 		}
612 block:
613 		state = rx_cleanup;
614 		entry->urb = urb;
615 		urb = NULL;
616 		break;
617 
618 	/* data overrun ... flush fifo? */
619 	case -EOVERFLOW:
620 		dev->net->stats.rx_over_errors++;
621 		// FALLTHROUGH
622 
623 	default:
624 		state = rx_cleanup;
625 		dev->net->stats.rx_errors++;
626 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
627 		break;
628 	}
629 
630 	/* stop rx if packet error rate is high */
631 	if (++dev->pkt_cnt > 30) {
632 		dev->pkt_cnt = 0;
633 		dev->pkt_err = 0;
634 	} else {
635 		if (state == rx_cleanup)
636 			dev->pkt_err++;
637 		if (dev->pkt_err > 20)
638 			set_bit(EVENT_RX_KILL, &dev->flags);
639 	}
640 
641 	state = defer_bh(dev, skb, &dev->rxq, state);
642 
643 	if (urb) {
644 		if (netif_running (dev->net) &&
645 		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
646 		    state != unlink_start) {
647 			rx_submit (dev, urb, GFP_ATOMIC);
648 			usb_mark_last_busy(dev->udev);
649 			return;
650 		}
651 		usb_free_urb (urb);
652 	}
653 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
654 }
655 
656 /*-------------------------------------------------------------------------*/
657 void usbnet_pause_rx(struct usbnet *dev)
658 {
659 	set_bit(EVENT_RX_PAUSED, &dev->flags);
660 
661 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
662 }
663 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
664 
665 void usbnet_resume_rx(struct usbnet *dev)
666 {
667 	struct sk_buff *skb;
668 	int num = 0;
669 
670 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
671 
672 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
673 		usbnet_skb_return(dev, skb);
674 		num++;
675 	}
676 
677 	tasklet_schedule(&dev->bh);
678 
679 	netif_dbg(dev, rx_status, dev->net,
680 		  "paused rx queue disabled, %d skbs requeued\n", num);
681 }
682 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
683 
684 void usbnet_purge_paused_rxq(struct usbnet *dev)
685 {
686 	skb_queue_purge(&dev->rxq_pause);
687 }
688 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
689 
690 /*-------------------------------------------------------------------------*/
691 
692 // unlink pending rx/tx; completion handlers do all other cleanup
693 
694 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
695 {
696 	unsigned long		flags;
697 	struct sk_buff		*skb;
698 	int			count = 0;
699 
700 	spin_lock_irqsave (&q->lock, flags);
701 	while (!skb_queue_empty(q)) {
702 		struct skb_data		*entry;
703 		struct urb		*urb;
704 		int			retval;
705 
706 		skb_queue_walk(q, skb) {
707 			entry = (struct skb_data *) skb->cb;
708 			if (entry->state != unlink_start)
709 				goto found;
710 		}
711 		break;
712 found:
713 		entry->state = unlink_start;
714 		urb = entry->urb;
715 
716 		/*
717 		 * Get reference count of the URB to avoid it to be
718 		 * freed during usb_unlink_urb, which may trigger
719 		 * use-after-free problem inside usb_unlink_urb since
720 		 * usb_unlink_urb is always racing with .complete
721 		 * handler(include defer_bh).
722 		 */
723 		usb_get_urb(urb);
724 		spin_unlock_irqrestore(&q->lock, flags);
725 		// during some PM-driven resume scenarios,
726 		// these (async) unlinks complete immediately
727 		retval = usb_unlink_urb (urb);
728 		if (retval != -EINPROGRESS && retval != 0)
729 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
730 		else
731 			count++;
732 		usb_put_urb(urb);
733 		spin_lock_irqsave(&q->lock, flags);
734 	}
735 	spin_unlock_irqrestore (&q->lock, flags);
736 	return count;
737 }
738 
739 // Flush all pending rx urbs
740 // minidrivers may need to do this when the MTU changes
741 
742 void usbnet_unlink_rx_urbs(struct usbnet *dev)
743 {
744 	if (netif_running(dev->net)) {
745 		(void) unlink_urbs (dev, &dev->rxq);
746 		tasklet_schedule(&dev->bh);
747 	}
748 }
749 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
750 
751 /*-------------------------------------------------------------------------*/
752 
753 // precondition: never called in_interrupt
754 static void usbnet_terminate_urbs(struct usbnet *dev)
755 {
756 	DECLARE_WAITQUEUE(wait, current);
757 	int temp;
758 
759 	/* ensure there are no more active urbs */
760 	add_wait_queue(&dev->wait, &wait);
761 	set_current_state(TASK_UNINTERRUPTIBLE);
762 	temp = unlink_urbs(dev, &dev->txq) +
763 		unlink_urbs(dev, &dev->rxq);
764 
765 	/* maybe wait for deletions to finish. */
766 	while (!skb_queue_empty(&dev->rxq)
767 		&& !skb_queue_empty(&dev->txq)
768 		&& !skb_queue_empty(&dev->done)) {
769 			schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
770 			set_current_state(TASK_UNINTERRUPTIBLE);
771 			netif_dbg(dev, ifdown, dev->net,
772 				  "waited for %d urb completions\n", temp);
773 	}
774 	set_current_state(TASK_RUNNING);
775 	remove_wait_queue(&dev->wait, &wait);
776 }
777 
778 int usbnet_stop (struct net_device *net)
779 {
780 	struct usbnet		*dev = netdev_priv(net);
781 	struct driver_info	*info = dev->driver_info;
782 	int			retval, pm;
783 
784 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
785 	netif_stop_queue (net);
786 
787 	netif_info(dev, ifdown, dev->net,
788 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
789 		   net->stats.rx_packets, net->stats.tx_packets,
790 		   net->stats.rx_errors, net->stats.tx_errors);
791 
792 	/* to not race resume */
793 	pm = usb_autopm_get_interface(dev->intf);
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 (!pm)
821 		usb_autopm_put_interface(dev->intf);
822 
823 	if (info->manage_power &&
824 	    !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags))
825 		info->manage_power(dev, 0);
826 	else
827 		usb_autopm_put_interface(dev->intf);
828 
829 	return 0;
830 }
831 EXPORT_SYMBOL_GPL(usbnet_stop);
832 
833 /*-------------------------------------------------------------------------*/
834 
835 // posts reads, and enables write queuing
836 
837 // precondition: never called in_interrupt
838 
839 int usbnet_open (struct net_device *net)
840 {
841 	struct usbnet		*dev = netdev_priv(net);
842 	int			retval;
843 	struct driver_info	*info = dev->driver_info;
844 
845 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
846 		netif_info(dev, ifup, dev->net,
847 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
848 			   retval,
849 			   dev->udev->bus->bus_name,
850 			   dev->udev->devpath,
851 			   info->description);
852 		goto done_nopm;
853 	}
854 
855 	// put into "known safe" state
856 	if (info->reset && (retval = info->reset (dev)) < 0) {
857 		netif_info(dev, ifup, dev->net,
858 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
859 			   retval,
860 			   dev->udev->bus->bus_name,
861 			   dev->udev->devpath,
862 			   info->description);
863 		goto done;
864 	}
865 
866 	/* hard_mtu or rx_urb_size may change in reset() */
867 	usbnet_update_max_qlen(dev);
868 
869 	// insist peer be connected
870 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
871 		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
872 		goto done;
873 	}
874 
875 	/* start any status interrupt transfer */
876 	if (dev->interrupt) {
877 		retval = usbnet_status_start(dev, GFP_KERNEL);
878 		if (retval < 0) {
879 			netif_err(dev, ifup, dev->net,
880 				  "intr submit %d\n", retval);
881 			goto done;
882 		}
883 	}
884 
885 	set_bit(EVENT_DEV_OPEN, &dev->flags);
886 	netif_start_queue (net);
887 	netif_info(dev, ifup, dev->net,
888 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
889 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
890 		   dev->net->mtu,
891 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
892 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
893 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
894 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
895 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
896 		   "simple");
897 
898 	/* reset rx error state */
899 	dev->pkt_cnt = 0;
900 	dev->pkt_err = 0;
901 	clear_bit(EVENT_RX_KILL, &dev->flags);
902 
903 	// delay posting reads until we're fully open
904 	tasklet_schedule (&dev->bh);
905 	if (info->manage_power) {
906 		retval = info->manage_power(dev, 1);
907 		if (retval < 0) {
908 			retval = 0;
909 			set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
910 		} else {
911 			usb_autopm_put_interface(dev->intf);
912 		}
913 	}
914 	return retval;
915 done:
916 	usb_autopm_put_interface(dev->intf);
917 done_nopm:
918 	return retval;
919 }
920 EXPORT_SYMBOL_GPL(usbnet_open);
921 
922 /*-------------------------------------------------------------------------*/
923 
924 /* ethtool methods; minidrivers may need to add some more, but
925  * they'll probably want to use this base set.
926  */
927 
928 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
929 {
930 	struct usbnet *dev = netdev_priv(net);
931 
932 	if (!dev->mii.mdio_read)
933 		return -EOPNOTSUPP;
934 
935 	return mii_ethtool_gset(&dev->mii, cmd);
936 }
937 EXPORT_SYMBOL_GPL(usbnet_get_settings);
938 
939 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
940 {
941 	struct usbnet *dev = netdev_priv(net);
942 	int retval;
943 
944 	if (!dev->mii.mdio_write)
945 		return -EOPNOTSUPP;
946 
947 	retval = mii_ethtool_sset(&dev->mii, cmd);
948 
949 	/* link speed/duplex might have changed */
950 	if (dev->driver_info->link_reset)
951 		dev->driver_info->link_reset(dev);
952 
953 	/* hard_mtu or rx_urb_size may change in link_reset() */
954 	usbnet_update_max_qlen(dev);
955 
956 	return retval;
957 
958 }
959 EXPORT_SYMBOL_GPL(usbnet_set_settings);
960 
961 u32 usbnet_get_link (struct net_device *net)
962 {
963 	struct usbnet *dev = netdev_priv(net);
964 
965 	/* If a check_connect is defined, return its result */
966 	if (dev->driver_info->check_connect)
967 		return dev->driver_info->check_connect (dev) == 0;
968 
969 	/* if the device has mii operations, use those */
970 	if (dev->mii.mdio_read)
971 		return mii_link_ok(&dev->mii);
972 
973 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
974 	return ethtool_op_get_link(net);
975 }
976 EXPORT_SYMBOL_GPL(usbnet_get_link);
977 
978 int usbnet_nway_reset(struct net_device *net)
979 {
980 	struct usbnet *dev = netdev_priv(net);
981 
982 	if (!dev->mii.mdio_write)
983 		return -EOPNOTSUPP;
984 
985 	return mii_nway_restart(&dev->mii);
986 }
987 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
988 
989 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
990 {
991 	struct usbnet *dev = netdev_priv(net);
992 
993 	strlcpy (info->driver, dev->driver_name, sizeof info->driver);
994 	strlcpy (info->version, DRIVER_VERSION, sizeof info->version);
995 	strlcpy (info->fw_version, dev->driver_info->description,
996 		sizeof info->fw_version);
997 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
998 }
999 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
1000 
1001 u32 usbnet_get_msglevel (struct net_device *net)
1002 {
1003 	struct usbnet *dev = netdev_priv(net);
1004 
1005 	return dev->msg_enable;
1006 }
1007 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
1008 
1009 void usbnet_set_msglevel (struct net_device *net, u32 level)
1010 {
1011 	struct usbnet *dev = netdev_priv(net);
1012 
1013 	dev->msg_enable = level;
1014 }
1015 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
1016 
1017 /* drivers may override default ethtool_ops in their bind() routine */
1018 static const struct ethtool_ops usbnet_ethtool_ops = {
1019 	.get_settings		= usbnet_get_settings,
1020 	.set_settings		= usbnet_set_settings,
1021 	.get_link		= usbnet_get_link,
1022 	.nway_reset		= usbnet_nway_reset,
1023 	.get_drvinfo		= usbnet_get_drvinfo,
1024 	.get_msglevel		= usbnet_get_msglevel,
1025 	.set_msglevel		= usbnet_set_msglevel,
1026 	.get_ts_info		= ethtool_op_get_ts_info,
1027 };
1028 
1029 /*-------------------------------------------------------------------------*/
1030 
1031 static void __handle_link_change(struct usbnet *dev)
1032 {
1033 	if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
1034 		return;
1035 
1036 	if (!netif_carrier_ok(dev->net)) {
1037 		/* kill URBs for reading packets to save bus bandwidth */
1038 		unlink_urbs(dev, &dev->rxq);
1039 
1040 		/*
1041 		 * tx_timeout will unlink URBs for sending packets and
1042 		 * tx queue is stopped by netcore after link becomes off
1043 		 */
1044 	} else {
1045 		/* submitting URBs for reading packets */
1046 		tasklet_schedule(&dev->bh);
1047 	}
1048 
1049 	/* hard_mtu or rx_urb_size may change during link change */
1050 	usbnet_update_max_qlen(dev);
1051 
1052 	clear_bit(EVENT_LINK_CHANGE, &dev->flags);
1053 }
1054 
1055 static void usbnet_set_rx_mode(struct net_device *net)
1056 {
1057 	struct usbnet		*dev = netdev_priv(net);
1058 
1059 	usbnet_defer_kevent(dev, EVENT_SET_RX_MODE);
1060 }
1061 
1062 static void __handle_set_rx_mode(struct usbnet *dev)
1063 {
1064 	if (dev->driver_info->set_rx_mode)
1065 		(dev->driver_info->set_rx_mode)(dev);
1066 
1067 	clear_bit(EVENT_SET_RX_MODE, &dev->flags);
1068 }
1069 
1070 /* work that cannot be done in interrupt context uses keventd.
1071  *
1072  * NOTE:  with 2.5 we could do more of this using completion callbacks,
1073  * especially now that control transfers can be queued.
1074  */
1075 static void
1076 kevent (struct work_struct *work)
1077 {
1078 	struct usbnet		*dev =
1079 		container_of(work, struct usbnet, kevent);
1080 	int			status;
1081 
1082 	/* usb_clear_halt() needs a thread context */
1083 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
1084 		unlink_urbs (dev, &dev->txq);
1085 		status = usb_autopm_get_interface(dev->intf);
1086 		if (status < 0)
1087 			goto fail_pipe;
1088 		status = usb_clear_halt (dev->udev, dev->out);
1089 		usb_autopm_put_interface(dev->intf);
1090 		if (status < 0 &&
1091 		    status != -EPIPE &&
1092 		    status != -ESHUTDOWN) {
1093 			if (netif_msg_tx_err (dev))
1094 fail_pipe:
1095 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
1096 					   status);
1097 		} else {
1098 			clear_bit (EVENT_TX_HALT, &dev->flags);
1099 			if (status != -ESHUTDOWN)
1100 				netif_wake_queue (dev->net);
1101 		}
1102 	}
1103 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
1104 		unlink_urbs (dev, &dev->rxq);
1105 		status = usb_autopm_get_interface(dev->intf);
1106 		if (status < 0)
1107 			goto fail_halt;
1108 		status = usb_clear_halt (dev->udev, dev->in);
1109 		usb_autopm_put_interface(dev->intf);
1110 		if (status < 0 &&
1111 		    status != -EPIPE &&
1112 		    status != -ESHUTDOWN) {
1113 			if (netif_msg_rx_err (dev))
1114 fail_halt:
1115 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
1116 					   status);
1117 		} else {
1118 			clear_bit (EVENT_RX_HALT, &dev->flags);
1119 			tasklet_schedule (&dev->bh);
1120 		}
1121 	}
1122 
1123 	/* tasklet could resubmit itself forever if memory is tight */
1124 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
1125 		struct urb	*urb = NULL;
1126 		int resched = 1;
1127 
1128 		if (netif_running (dev->net))
1129 			urb = usb_alloc_urb (0, GFP_KERNEL);
1130 		else
1131 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1132 		if (urb != NULL) {
1133 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1134 			status = usb_autopm_get_interface(dev->intf);
1135 			if (status < 0) {
1136 				usb_free_urb(urb);
1137 				goto fail_lowmem;
1138 			}
1139 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
1140 				resched = 0;
1141 			usb_autopm_put_interface(dev->intf);
1142 fail_lowmem:
1143 			if (resched)
1144 				tasklet_schedule (&dev->bh);
1145 		}
1146 	}
1147 
1148 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
1149 		struct driver_info	*info = dev->driver_info;
1150 		int			retval = 0;
1151 
1152 		clear_bit (EVENT_LINK_RESET, &dev->flags);
1153 		status = usb_autopm_get_interface(dev->intf);
1154 		if (status < 0)
1155 			goto skip_reset;
1156 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1157 			usb_autopm_put_interface(dev->intf);
1158 skip_reset:
1159 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1160 				    retval,
1161 				    dev->udev->bus->bus_name,
1162 				    dev->udev->devpath,
1163 				    info->description);
1164 		} else {
1165 			usb_autopm_put_interface(dev->intf);
1166 		}
1167 
1168 		/* handle link change from link resetting */
1169 		__handle_link_change(dev);
1170 	}
1171 
1172 	if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
1173 		__handle_link_change(dev);
1174 
1175 	if (test_bit (EVENT_SET_RX_MODE, &dev->flags))
1176 		__handle_set_rx_mode(dev);
1177 
1178 
1179 	if (dev->flags)
1180 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1181 }
1182 
1183 /*-------------------------------------------------------------------------*/
1184 
1185 static void tx_complete (struct urb *urb)
1186 {
1187 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1188 	struct skb_data		*entry = (struct skb_data *) skb->cb;
1189 	struct usbnet		*dev = entry->dev;
1190 
1191 	if (urb->status == 0) {
1192 		if (!(dev->driver_info->flags & FLAG_MULTI_PACKET))
1193 			dev->net->stats.tx_packets++;
1194 		dev->net->stats.tx_bytes += entry->length;
1195 	} else {
1196 		dev->net->stats.tx_errors++;
1197 
1198 		switch (urb->status) {
1199 		case -EPIPE:
1200 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1201 			break;
1202 
1203 		/* software-driven interface shutdown */
1204 		case -ECONNRESET:		// async unlink
1205 		case -ESHUTDOWN:		// hardware gone
1206 			break;
1207 
1208 		/* like rx, tx gets controller i/o faults during hub_wq
1209 		 * delays and so it uses the same throttling mechanism.
1210 		 */
1211 		case -EPROTO:
1212 		case -ETIME:
1213 		case -EILSEQ:
1214 			usb_mark_last_busy(dev->udev);
1215 			if (!timer_pending (&dev->delay)) {
1216 				mod_timer (&dev->delay,
1217 					jiffies + THROTTLE_JIFFIES);
1218 				netif_dbg(dev, link, dev->net,
1219 					  "tx throttle %d\n", urb->status);
1220 			}
1221 			netif_stop_queue (dev->net);
1222 			break;
1223 		default:
1224 			netif_dbg(dev, tx_err, dev->net,
1225 				  "tx err %d\n", entry->urb->status);
1226 			break;
1227 		}
1228 	}
1229 
1230 	usb_autopm_put_interface_async(dev->intf);
1231 	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1232 }
1233 
1234 /*-------------------------------------------------------------------------*/
1235 
1236 void usbnet_tx_timeout (struct net_device *net)
1237 {
1238 	struct usbnet		*dev = netdev_priv(net);
1239 
1240 	unlink_urbs (dev, &dev->txq);
1241 	tasklet_schedule (&dev->bh);
1242 	/* this needs to be handled individually because the generic layer
1243 	 * doesn't know what is sufficient and could not restore private
1244 	 * information if a remedy of an unconditional reset were used.
1245 	 */
1246 	if (dev->driver_info->recover)
1247 		(dev->driver_info->recover)(dev);
1248 }
1249 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1250 
1251 /*-------------------------------------------------------------------------*/
1252 
1253 static int build_dma_sg(const struct sk_buff *skb, struct urb *urb)
1254 {
1255 	unsigned num_sgs, total_len = 0;
1256 	int i, s = 0;
1257 
1258 	num_sgs = skb_shinfo(skb)->nr_frags + 1;
1259 	if (num_sgs == 1)
1260 		return 0;
1261 
1262 	/* reserve one for zero packet */
1263 	urb->sg = kmalloc((num_sgs + 1) * sizeof(struct scatterlist),
1264 			  GFP_ATOMIC);
1265 	if (!urb->sg)
1266 		return -ENOMEM;
1267 
1268 	urb->num_sgs = num_sgs;
1269 	sg_init_table(urb->sg, urb->num_sgs + 1);
1270 
1271 	sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb));
1272 	total_len += skb_headlen(skb);
1273 
1274 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1275 		struct skb_frag_struct *f = &skb_shinfo(skb)->frags[i];
1276 
1277 		total_len += skb_frag_size(f);
1278 		sg_set_page(&urb->sg[i + s], f->page.p, f->size,
1279 				f->page_offset);
1280 	}
1281 	urb->transfer_buffer_length = total_len;
1282 
1283 	return 1;
1284 }
1285 
1286 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1287 				     struct net_device *net)
1288 {
1289 	struct usbnet		*dev = netdev_priv(net);
1290 	int			length;
1291 	struct urb		*urb = NULL;
1292 	struct skb_data		*entry;
1293 	struct driver_info	*info = dev->driver_info;
1294 	unsigned long		flags;
1295 	int retval;
1296 
1297 	if (skb)
1298 		skb_tx_timestamp(skb);
1299 
1300 	// some devices want funky USB-level framing, for
1301 	// win32 driver (usually) and/or hardware quirks
1302 	if (info->tx_fixup) {
1303 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1304 		if (!skb) {
1305 			/* packet collected; minidriver waiting for more */
1306 			if (info->flags & FLAG_MULTI_PACKET)
1307 				goto not_drop;
1308 			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1309 			goto drop;
1310 		}
1311 	}
1312 
1313 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1314 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1315 		goto drop;
1316 	}
1317 
1318 	entry = (struct skb_data *) skb->cb;
1319 	entry->urb = urb;
1320 	entry->dev = dev;
1321 
1322 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1323 			skb->data, skb->len, tx_complete, skb);
1324 	if (dev->can_dma_sg) {
1325 		if (build_dma_sg(skb, urb) < 0)
1326 			goto drop;
1327 	}
1328 	length = urb->transfer_buffer_length;
1329 
1330 	/* don't assume the hardware handles USB_ZERO_PACKET
1331 	 * NOTE:  strictly conforming cdc-ether devices should expect
1332 	 * the ZLP here, but ignore the one-byte packet.
1333 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1334 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1335 	 * packet itself if needed.
1336 	 */
1337 	if (length % dev->maxpacket == 0) {
1338 		if (!(info->flags & FLAG_SEND_ZLP)) {
1339 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1340 				length++;
1341 				if (skb_tailroom(skb) && !urb->num_sgs) {
1342 					skb->data[skb->len] = 0;
1343 					__skb_put(skb, 1);
1344 				} else if (urb->num_sgs)
1345 					sg_set_buf(&urb->sg[urb->num_sgs++],
1346 							dev->padding_pkt, 1);
1347 			}
1348 		} else
1349 			urb->transfer_flags |= URB_ZERO_PACKET;
1350 	}
1351 	entry->length = urb->transfer_buffer_length = length;
1352 
1353 	spin_lock_irqsave(&dev->txq.lock, flags);
1354 	retval = usb_autopm_get_interface_async(dev->intf);
1355 	if (retval < 0) {
1356 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1357 		goto drop;
1358 	}
1359 
1360 #ifdef CONFIG_PM
1361 	/* if this triggers the device is still a sleep */
1362 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1363 		/* transmission will be done in resume */
1364 		usb_anchor_urb(urb, &dev->deferred);
1365 		/* no use to process more packets */
1366 		netif_stop_queue(net);
1367 		usb_put_urb(urb);
1368 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1369 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1370 		goto deferred;
1371 	}
1372 #endif
1373 
1374 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1375 	case -EPIPE:
1376 		netif_stop_queue (net);
1377 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1378 		usb_autopm_put_interface_async(dev->intf);
1379 		break;
1380 	default:
1381 		usb_autopm_put_interface_async(dev->intf);
1382 		netif_dbg(dev, tx_err, dev->net,
1383 			  "tx: submit urb err %d\n", retval);
1384 		break;
1385 	case 0:
1386 		net->trans_start = jiffies;
1387 		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1388 		if (dev->txq.qlen >= TX_QLEN (dev))
1389 			netif_stop_queue (net);
1390 	}
1391 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1392 
1393 	if (retval) {
1394 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1395 drop:
1396 		dev->net->stats.tx_dropped++;
1397 not_drop:
1398 		if (skb)
1399 			dev_kfree_skb_any (skb);
1400 		if (urb) {
1401 			kfree(urb->sg);
1402 			usb_free_urb(urb);
1403 		}
1404 	} else
1405 		netif_dbg(dev, tx_queued, dev->net,
1406 			  "> tx, len %d, type 0x%x\n", length, skb->protocol);
1407 #ifdef CONFIG_PM
1408 deferred:
1409 #endif
1410 	return NETDEV_TX_OK;
1411 }
1412 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1413 
1414 static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1415 {
1416 	struct urb	*urb;
1417 	int		i;
1418 	int		ret = 0;
1419 
1420 	/* don't refill the queue all at once */
1421 	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1422 		urb = usb_alloc_urb(0, flags);
1423 		if (urb != NULL) {
1424 			ret = rx_submit(dev, urb, flags);
1425 			if (ret)
1426 				goto err;
1427 		} else {
1428 			ret = -ENOMEM;
1429 			goto err;
1430 		}
1431 	}
1432 err:
1433 	return ret;
1434 }
1435 
1436 /*-------------------------------------------------------------------------*/
1437 
1438 // tasklet (work deferred from completions, in_irq) or timer
1439 
1440 static void usbnet_bh (unsigned long param)
1441 {
1442 	struct usbnet		*dev = (struct usbnet *) param;
1443 	struct sk_buff		*skb;
1444 	struct skb_data		*entry;
1445 
1446 	while ((skb = skb_dequeue (&dev->done))) {
1447 		entry = (struct skb_data *) skb->cb;
1448 		switch (entry->state) {
1449 		case rx_done:
1450 			entry->state = rx_cleanup;
1451 			rx_process (dev, skb);
1452 			continue;
1453 		case tx_done:
1454 			kfree(entry->urb->sg);
1455 		case rx_cleanup:
1456 			usb_free_urb (entry->urb);
1457 			dev_kfree_skb (skb);
1458 			continue;
1459 		default:
1460 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1461 		}
1462 	}
1463 
1464 	/* restart RX again after disabling due to high error rate */
1465 	clear_bit(EVENT_RX_KILL, &dev->flags);
1466 
1467 	/* waiting for all pending urbs to complete?
1468 	 * only then can we forgo submitting anew
1469 	 */
1470 	if (waitqueue_active(&dev->wait)) {
1471 		if (dev->txq.qlen + dev->rxq.qlen + dev->done.qlen == 0)
1472 			wake_up_all(&dev->wait);
1473 
1474 	// or are we maybe short a few urbs?
1475 	} else if (netif_running (dev->net) &&
1476 		   netif_device_present (dev->net) &&
1477 		   netif_carrier_ok(dev->net) &&
1478 		   !timer_pending (&dev->delay) &&
1479 		   !test_bit (EVENT_RX_HALT, &dev->flags)) {
1480 		int	temp = dev->rxq.qlen;
1481 
1482 		if (temp < RX_QLEN(dev)) {
1483 			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1484 				return;
1485 			if (temp != dev->rxq.qlen)
1486 				netif_dbg(dev, link, dev->net,
1487 					  "rxqlen %d --> %d\n",
1488 					  temp, dev->rxq.qlen);
1489 			if (dev->rxq.qlen < RX_QLEN(dev))
1490 				tasklet_schedule (&dev->bh);
1491 		}
1492 		if (dev->txq.qlen < TX_QLEN (dev))
1493 			netif_wake_queue (dev->net);
1494 	}
1495 }
1496 
1497 
1498 /*-------------------------------------------------------------------------
1499  *
1500  * USB Device Driver support
1501  *
1502  *-------------------------------------------------------------------------*/
1503 
1504 // precondition: never called in_interrupt
1505 
1506 void usbnet_disconnect (struct usb_interface *intf)
1507 {
1508 	struct usbnet		*dev;
1509 	struct usb_device	*xdev;
1510 	struct net_device	*net;
1511 
1512 	dev = usb_get_intfdata(intf);
1513 	usb_set_intfdata(intf, NULL);
1514 	if (!dev)
1515 		return;
1516 
1517 	xdev = interface_to_usbdev (intf);
1518 
1519 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1520 		   intf->dev.driver->name,
1521 		   xdev->bus->bus_name, xdev->devpath,
1522 		   dev->driver_info->description);
1523 
1524 	net = dev->net;
1525 	unregister_netdev (net);
1526 
1527 	cancel_work_sync(&dev->kevent);
1528 
1529 	usb_scuttle_anchored_urbs(&dev->deferred);
1530 
1531 	if (dev->driver_info->unbind)
1532 		dev->driver_info->unbind (dev, intf);
1533 
1534 	usb_kill_urb(dev->interrupt);
1535 	usb_free_urb(dev->interrupt);
1536 	kfree(dev->padding_pkt);
1537 
1538 	free_netdev(net);
1539 }
1540 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1541 
1542 static const struct net_device_ops usbnet_netdev_ops = {
1543 	.ndo_open		= usbnet_open,
1544 	.ndo_stop		= usbnet_stop,
1545 	.ndo_start_xmit		= usbnet_start_xmit,
1546 	.ndo_tx_timeout		= usbnet_tx_timeout,
1547 	.ndo_set_rx_mode	= usbnet_set_rx_mode,
1548 	.ndo_change_mtu		= usbnet_change_mtu,
1549 	.ndo_set_mac_address 	= eth_mac_addr,
1550 	.ndo_validate_addr	= eth_validate_addr,
1551 };
1552 
1553 /*-------------------------------------------------------------------------*/
1554 
1555 // precondition: never called in_interrupt
1556 
1557 static struct device_type wlan_type = {
1558 	.name	= "wlan",
1559 };
1560 
1561 static struct device_type wwan_type = {
1562 	.name	= "wwan",
1563 };
1564 
1565 int
1566 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1567 {
1568 	struct usbnet			*dev;
1569 	struct net_device		*net;
1570 	struct usb_host_interface	*interface;
1571 	struct driver_info		*info;
1572 	struct usb_device		*xdev;
1573 	int				status;
1574 	const char			*name;
1575 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1576 
1577 	/* usbnet already took usb runtime pm, so have to enable the feature
1578 	 * for usb interface, otherwise usb_autopm_get_interface may return
1579 	 * failure if RUNTIME_PM is enabled.
1580 	 */
1581 	if (!driver->supports_autosuspend) {
1582 		driver->supports_autosuspend = 1;
1583 		pm_runtime_enable(&udev->dev);
1584 	}
1585 
1586 	name = udev->dev.driver->name;
1587 	info = (struct driver_info *) prod->driver_info;
1588 	if (!info) {
1589 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1590 		return -ENODEV;
1591 	}
1592 	xdev = interface_to_usbdev (udev);
1593 	interface = udev->cur_altsetting;
1594 
1595 	status = -ENOMEM;
1596 
1597 	// set up our own records
1598 	net = alloc_etherdev(sizeof(*dev));
1599 	if (!net)
1600 		goto out;
1601 
1602 	/* netdev_printk() needs this so do it as early as possible */
1603 	SET_NETDEV_DEV(net, &udev->dev);
1604 
1605 	dev = netdev_priv(net);
1606 	dev->udev = xdev;
1607 	dev->intf = udev;
1608 	dev->driver_info = info;
1609 	dev->driver_name = name;
1610 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1611 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1612 	init_waitqueue_head(&dev->wait);
1613 	skb_queue_head_init (&dev->rxq);
1614 	skb_queue_head_init (&dev->txq);
1615 	skb_queue_head_init (&dev->done);
1616 	skb_queue_head_init(&dev->rxq_pause);
1617 	dev->bh.func = usbnet_bh;
1618 	dev->bh.data = (unsigned long) dev;
1619 	INIT_WORK (&dev->kevent, kevent);
1620 	init_usb_anchor(&dev->deferred);
1621 	dev->delay.function = usbnet_bh;
1622 	dev->delay.data = (unsigned long) dev;
1623 	init_timer (&dev->delay);
1624 	mutex_init (&dev->phy_mutex);
1625 	mutex_init(&dev->interrupt_mutex);
1626 	dev->interrupt_count = 0;
1627 
1628 	dev->net = net;
1629 	strcpy (net->name, "usb%d");
1630 	memcpy (net->dev_addr, node_id, sizeof node_id);
1631 
1632 	/* rx and tx sides can use different message sizes;
1633 	 * bind() should set rx_urb_size in that case.
1634 	 */
1635 	dev->hard_mtu = net->mtu + net->hard_header_len;
1636 #if 0
1637 // dma_supported() is deeply broken on almost all architectures
1638 	// possible with some EHCI controllers
1639 	if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1640 		net->features |= NETIF_F_HIGHDMA;
1641 #endif
1642 
1643 	net->netdev_ops = &usbnet_netdev_ops;
1644 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1645 	net->ethtool_ops = &usbnet_ethtool_ops;
1646 
1647 	// allow device-specific bind/init procedures
1648 	// NOTE net->name still not usable ...
1649 	if (info->bind) {
1650 		status = info->bind (dev, udev);
1651 		if (status < 0)
1652 			goto out1;
1653 
1654 		// heuristic:  "usb%d" for links we know are two-host,
1655 		// else "eth%d" when there's reasonable doubt.  userspace
1656 		// can rename the link if it knows better.
1657 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1658 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1659 		     (net->dev_addr [0] & 0x02) == 0))
1660 			strcpy (net->name, "eth%d");
1661 		/* WLAN devices should always be named "wlan%d" */
1662 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1663 			strcpy(net->name, "wlan%d");
1664 		/* WWAN devices should always be named "wwan%d" */
1665 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1666 			strcpy(net->name, "wwan%d");
1667 
1668 		/* devices that cannot do ARP */
1669 		if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1670 			net->flags |= IFF_NOARP;
1671 
1672 		/* maybe the remote can't receive an Ethernet MTU */
1673 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1674 			net->mtu = dev->hard_mtu - net->hard_header_len;
1675 	} else if (!info->in || !info->out)
1676 		status = usbnet_get_endpoints (dev, udev);
1677 	else {
1678 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1679 		dev->out = usb_sndbulkpipe (xdev, info->out);
1680 		if (!(info->flags & FLAG_NO_SETINT))
1681 			status = usb_set_interface (xdev,
1682 				interface->desc.bInterfaceNumber,
1683 				interface->desc.bAlternateSetting);
1684 		else
1685 			status = 0;
1686 
1687 	}
1688 	if (status >= 0 && dev->status)
1689 		status = init_status (dev, udev);
1690 	if (status < 0)
1691 		goto out3;
1692 
1693 	if (!dev->rx_urb_size)
1694 		dev->rx_urb_size = dev->hard_mtu;
1695 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1696 
1697 	/* let userspace know we have a random address */
1698 	if (ether_addr_equal(net->dev_addr, node_id))
1699 		net->addr_assign_type = NET_ADDR_RANDOM;
1700 
1701 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1702 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1703 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1704 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1705 
1706 	/* initialize max rx_qlen and tx_qlen */
1707 	usbnet_update_max_qlen(dev);
1708 
1709 	if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&
1710 		!(info->flags & FLAG_MULTI_PACKET)) {
1711 		dev->padding_pkt = kzalloc(1, GFP_KERNEL);
1712 		if (!dev->padding_pkt) {
1713 			status = -ENOMEM;
1714 			goto out4;
1715 		}
1716 	}
1717 
1718 	status = register_netdev (net);
1719 	if (status)
1720 		goto out5;
1721 	netif_info(dev, probe, dev->net,
1722 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1723 		   udev->dev.driver->name,
1724 		   xdev->bus->bus_name, xdev->devpath,
1725 		   dev->driver_info->description,
1726 		   net->dev_addr);
1727 
1728 	// ok, it's ready to go.
1729 	usb_set_intfdata (udev, dev);
1730 
1731 	netif_device_attach (net);
1732 
1733 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1734 		usbnet_link_change(dev, 0, 0);
1735 
1736 	return 0;
1737 
1738 out5:
1739 	kfree(dev->padding_pkt);
1740 out4:
1741 	usb_free_urb(dev->interrupt);
1742 out3:
1743 	if (info->unbind)
1744 		info->unbind (dev, udev);
1745 out1:
1746 	free_netdev(net);
1747 out:
1748 	return status;
1749 }
1750 EXPORT_SYMBOL_GPL(usbnet_probe);
1751 
1752 /*-------------------------------------------------------------------------*/
1753 
1754 /*
1755  * suspend the whole driver as soon as the first interface is suspended
1756  * resume only when the last interface is resumed
1757  */
1758 
1759 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1760 {
1761 	struct usbnet		*dev = usb_get_intfdata(intf);
1762 
1763 	if (!dev->suspend_count++) {
1764 		spin_lock_irq(&dev->txq.lock);
1765 		/* don't autosuspend while transmitting */
1766 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1767 			dev->suspend_count--;
1768 			spin_unlock_irq(&dev->txq.lock);
1769 			return -EBUSY;
1770 		} else {
1771 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1772 			spin_unlock_irq(&dev->txq.lock);
1773 		}
1774 		/*
1775 		 * accelerate emptying of the rx and queues, to avoid
1776 		 * having everything error out.
1777 		 */
1778 		netif_device_detach (dev->net);
1779 		usbnet_terminate_urbs(dev);
1780 		__usbnet_status_stop_force(dev);
1781 
1782 		/*
1783 		 * reattach so runtime management can use and
1784 		 * wake the device
1785 		 */
1786 		netif_device_attach (dev->net);
1787 	}
1788 	return 0;
1789 }
1790 EXPORT_SYMBOL_GPL(usbnet_suspend);
1791 
1792 int usbnet_resume (struct usb_interface *intf)
1793 {
1794 	struct usbnet		*dev = usb_get_intfdata(intf);
1795 	struct sk_buff          *skb;
1796 	struct urb              *res;
1797 	int                     retval;
1798 
1799 	if (!--dev->suspend_count) {
1800 		/* resume interrupt URB if it was previously submitted */
1801 		__usbnet_status_start_force(dev, GFP_NOIO);
1802 
1803 		spin_lock_irq(&dev->txq.lock);
1804 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1805 
1806 			skb = (struct sk_buff *)res->context;
1807 			retval = usb_submit_urb(res, GFP_ATOMIC);
1808 			if (retval < 0) {
1809 				dev_kfree_skb_any(skb);
1810 				kfree(res->sg);
1811 				usb_free_urb(res);
1812 				usb_autopm_put_interface_async(dev->intf);
1813 			} else {
1814 				dev->net->trans_start = jiffies;
1815 				__skb_queue_tail(&dev->txq, skb);
1816 			}
1817 		}
1818 
1819 		smp_mb();
1820 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1821 		spin_unlock_irq(&dev->txq.lock);
1822 
1823 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1824 			/* handle remote wakeup ASAP
1825 			 * we cannot race against stop
1826 			 */
1827 			if (netif_device_present(dev->net) &&
1828 				!timer_pending(&dev->delay) &&
1829 				!test_bit(EVENT_RX_HALT, &dev->flags))
1830 					rx_alloc_submit(dev, GFP_NOIO);
1831 
1832 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1833 				netif_tx_wake_all_queues(dev->net);
1834 			tasklet_schedule (&dev->bh);
1835 		}
1836 	}
1837 
1838 	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1839 		usb_autopm_get_interface_no_resume(intf);
1840 
1841 	return 0;
1842 }
1843 EXPORT_SYMBOL_GPL(usbnet_resume);
1844 
1845 /*
1846  * Either a subdriver implements manage_power, then it is assumed to always
1847  * be ready to be suspended or it reports the readiness to be suspended
1848  * explicitly
1849  */
1850 void usbnet_device_suggests_idle(struct usbnet *dev)
1851 {
1852 	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1853 		dev->intf->needs_remote_wakeup = 1;
1854 		usb_autopm_put_interface_async(dev->intf);
1855 	}
1856 }
1857 EXPORT_SYMBOL(usbnet_device_suggests_idle);
1858 
1859 /*
1860  * For devices that can do without special commands
1861  */
1862 int usbnet_manage_power(struct usbnet *dev, int on)
1863 {
1864 	dev->intf->needs_remote_wakeup = on;
1865 	return 0;
1866 }
1867 EXPORT_SYMBOL(usbnet_manage_power);
1868 
1869 void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
1870 {
1871 	/* update link after link is reseted */
1872 	if (link && !need_reset)
1873 		netif_carrier_on(dev->net);
1874 	else
1875 		netif_carrier_off(dev->net);
1876 
1877 	if (need_reset && link)
1878 		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
1879 	else
1880 		usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
1881 }
1882 EXPORT_SYMBOL(usbnet_link_change);
1883 
1884 /*-------------------------------------------------------------------------*/
1885 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1886 			     u16 value, u16 index, void *data, u16 size)
1887 {
1888 	void *buf = NULL;
1889 	int err = -ENOMEM;
1890 
1891 	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
1892 		   " value=0x%04x index=0x%04x size=%d\n",
1893 		   cmd, reqtype, value, index, size);
1894 
1895 	if (data) {
1896 		buf = kmalloc(size, GFP_KERNEL);
1897 		if (!buf)
1898 			goto out;
1899 	}
1900 
1901 	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
1902 			      cmd, reqtype, value, index, buf, size,
1903 			      USB_CTRL_GET_TIMEOUT);
1904 	if (err > 0 && err <= size)
1905 		memcpy(data, buf, err);
1906 	kfree(buf);
1907 out:
1908 	return err;
1909 }
1910 
1911 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1912 			      u16 value, u16 index, const void *data,
1913 			      u16 size)
1914 {
1915 	void *buf = NULL;
1916 	int err = -ENOMEM;
1917 
1918 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
1919 		   " value=0x%04x index=0x%04x size=%d\n",
1920 		   cmd, reqtype, value, index, size);
1921 
1922 	if (data) {
1923 		buf = kmemdup(data, size, GFP_KERNEL);
1924 		if (!buf)
1925 			goto out;
1926 	}
1927 
1928 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
1929 			      cmd, reqtype, value, index, buf, size,
1930 			      USB_CTRL_SET_TIMEOUT);
1931 	kfree(buf);
1932 
1933 out:
1934 	return err;
1935 }
1936 
1937 /*
1938  * The function can't be called inside suspend/resume callback,
1939  * otherwise deadlock will be caused.
1940  */
1941 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1942 		    u16 value, u16 index, void *data, u16 size)
1943 {
1944 	int ret;
1945 
1946 	if (usb_autopm_get_interface(dev->intf) < 0)
1947 		return -ENODEV;
1948 	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
1949 				data, size);
1950 	usb_autopm_put_interface(dev->intf);
1951 	return ret;
1952 }
1953 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
1954 
1955 /*
1956  * The function can't be called inside suspend/resume callback,
1957  * otherwise deadlock will be caused.
1958  */
1959 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1960 		     u16 value, u16 index, const void *data, u16 size)
1961 {
1962 	int ret;
1963 
1964 	if (usb_autopm_get_interface(dev->intf) < 0)
1965 		return -ENODEV;
1966 	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
1967 				 data, size);
1968 	usb_autopm_put_interface(dev->intf);
1969 	return ret;
1970 }
1971 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
1972 
1973 /*
1974  * The function can be called inside suspend/resume callback safely
1975  * and should only be called by suspend/resume callback generally.
1976  */
1977 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
1978 			  u16 value, u16 index, void *data, u16 size)
1979 {
1980 	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
1981 				 data, size);
1982 }
1983 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
1984 
1985 /*
1986  * The function can be called inside suspend/resume callback safely
1987  * and should only be called by suspend/resume callback generally.
1988  */
1989 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
1990 			  u16 value, u16 index, const void *data,
1991 			  u16 size)
1992 {
1993 	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
1994 				  data, size);
1995 }
1996 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
1997 
1998 static void usbnet_async_cmd_cb(struct urb *urb)
1999 {
2000 	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
2001 	int status = urb->status;
2002 
2003 	if (status < 0)
2004 		dev_dbg(&urb->dev->dev, "%s failed with %d",
2005 			__func__, status);
2006 
2007 	kfree(req);
2008 	usb_free_urb(urb);
2009 }
2010 
2011 /*
2012  * The caller must make sure that device can't be put into suspend
2013  * state until the control URB completes.
2014  */
2015 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
2016 			   u16 value, u16 index, const void *data, u16 size)
2017 {
2018 	struct usb_ctrlrequest *req = NULL;
2019 	struct urb *urb;
2020 	int err = -ENOMEM;
2021 	void *buf = NULL;
2022 
2023 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2024 		   " value=0x%04x index=0x%04x size=%d\n",
2025 		   cmd, reqtype, value, index, size);
2026 
2027 	urb = usb_alloc_urb(0, GFP_ATOMIC);
2028 	if (!urb) {
2029 		netdev_err(dev->net, "Error allocating URB in"
2030 			   " %s!\n", __func__);
2031 		goto fail;
2032 	}
2033 
2034 	if (data) {
2035 		buf = kmemdup(data, size, GFP_ATOMIC);
2036 		if (!buf) {
2037 			netdev_err(dev->net, "Error allocating buffer"
2038 				   " in %s!\n", __func__);
2039 			goto fail_free;
2040 		}
2041 	}
2042 
2043 	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
2044 	if (!req)
2045 		goto fail_free_buf;
2046 
2047 	req->bRequestType = reqtype;
2048 	req->bRequest = cmd;
2049 	req->wValue = cpu_to_le16(value);
2050 	req->wIndex = cpu_to_le16(index);
2051 	req->wLength = cpu_to_le16(size);
2052 
2053 	usb_fill_control_urb(urb, dev->udev,
2054 			     usb_sndctrlpipe(dev->udev, 0),
2055 			     (void *)req, buf, size,
2056 			     usbnet_async_cmd_cb, req);
2057 	urb->transfer_flags |= URB_FREE_BUFFER;
2058 
2059 	err = usb_submit_urb(urb, GFP_ATOMIC);
2060 	if (err < 0) {
2061 		netdev_err(dev->net, "Error submitting the control"
2062 			   " message: status=%d\n", err);
2063 		goto fail_free;
2064 	}
2065 	return 0;
2066 
2067 fail_free_buf:
2068 	kfree(buf);
2069 fail_free:
2070 	kfree(req);
2071 	usb_free_urb(urb);
2072 fail:
2073 	return err;
2074 
2075 }
2076 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
2077 /*-------------------------------------------------------------------------*/
2078 
2079 static int __init usbnet_init(void)
2080 {
2081 	/* Compiler should optimize this out. */
2082 	BUILD_BUG_ON(
2083 		FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
2084 
2085 	eth_random_addr(node_id);
2086 	return 0;
2087 }
2088 module_init(usbnet_init);
2089 
2090 static void __exit usbnet_exit(void)
2091 {
2092 }
2093 module_exit(usbnet_exit);
2094 
2095 MODULE_AUTHOR("David Brownell");
2096 MODULE_DESCRIPTION("USB network driver framework");
2097 MODULE_LICENSE("GPL");
2098