xref: /linux/drivers/net/usb/usbnet.c (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5)
1 /*
2  * USB Network driver infrastructure
3  * Copyright (C) 2000-2005 by David Brownell
4  * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19  */
20 
21 /*
22  * This is a generic "USB networking" framework that works with several
23  * kinds of full and high speed networking devices:  host-to-host cables,
24  * smart usb peripherals, and actual Ethernet adapters.
25  *
26  * These devices usually differ in terms of control protocols (if they
27  * even have one!) and sometimes they define new framing to wrap or batch
28  * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
29  * so interface (un)binding, endpoint I/O queues, fault handling, and other
30  * issues can usefully be addressed by this framework.
31  */
32 
33 // #define	DEBUG			// error path messages, extra info
34 // #define	VERBOSE			// more; success messages
35 
36 #include <linux/module.h>
37 #include <linux/init.h>
38 #include <linux/netdevice.h>
39 #include <linux/etherdevice.h>
40 #include <linux/ctype.h>
41 #include <linux/ethtool.h>
42 #include <linux/workqueue.h>
43 #include <linux/mii.h>
44 #include <linux/usb.h>
45 #include <linux/usb/usbnet.h>
46 #include <linux/slab.h>
47 #include <linux/kernel.h>
48 #include <linux/pm_runtime.h>
49 
50 #define DRIVER_VERSION		"22-Aug-2005"
51 
52 
53 /*-------------------------------------------------------------------------*/
54 
55 /*
56  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
57  * Several dozen bytes of IPv4 data can fit in two such transactions.
58  * One maximum size Ethernet packet takes twenty four of them.
59  * For high speed, each frame comfortably fits almost 36 max size
60  * Ethernet packets (so queues should be bigger).
61  *
62  * REVISIT qlens should be members of 'struct usbnet'; the goal is to
63  * let the USB host controller be busy for 5msec or more before an irq
64  * is required, under load.  Jumbograms change the equation.
65  */
66 #define RX_MAX_QUEUE_MEMORY (60 * 1518)
67 #define	RX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
68 			(RX_MAX_QUEUE_MEMORY/(dev)->rx_urb_size) : 4)
69 #define	TX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
70 			(RX_MAX_QUEUE_MEMORY/(dev)->hard_mtu) : 4)
71 
72 // reawaken network queue this soon after stopping; else watchdog barks
73 #define TX_TIMEOUT_JIFFIES	(5*HZ)
74 
75 // throttle rx/tx briefly after some faults, so khubd might disconnect()
76 // us (it polls at HZ/4 usually) before we report too many false errors.
77 #define THROTTLE_JIFFIES	(HZ/8)
78 
79 // between wakeups
80 #define UNLINK_TIMEOUT_MS	3
81 
82 /*-------------------------------------------------------------------------*/
83 
84 // randomly generated ethernet address
85 static u8	node_id [ETH_ALEN];
86 
87 static const char driver_name [] = "usbnet";
88 
89 /* use ethtool to change the level for any given device */
90 static int msg_level = -1;
91 module_param (msg_level, int, 0);
92 MODULE_PARM_DESC (msg_level, "Override default message level");
93 
94 /*-------------------------------------------------------------------------*/
95 
96 /* handles CDC Ethernet and many other network "bulk data" interfaces */
97 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
98 {
99 	int				tmp;
100 	struct usb_host_interface	*alt = NULL;
101 	struct usb_host_endpoint	*in = NULL, *out = NULL;
102 	struct usb_host_endpoint	*status = NULL;
103 
104 	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
105 		unsigned	ep;
106 
107 		in = out = status = NULL;
108 		alt = intf->altsetting + tmp;
109 
110 		/* take the first altsetting with in-bulk + out-bulk;
111 		 * remember any status endpoint, just in case;
112 		 * ignore other endpoints and altsettings.
113 		 */
114 		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
115 			struct usb_host_endpoint	*e;
116 			int				intr = 0;
117 
118 			e = alt->endpoint + ep;
119 			switch (e->desc.bmAttributes) {
120 			case USB_ENDPOINT_XFER_INT:
121 				if (!usb_endpoint_dir_in(&e->desc))
122 					continue;
123 				intr = 1;
124 				/* FALLTHROUGH */
125 			case USB_ENDPOINT_XFER_BULK:
126 				break;
127 			default:
128 				continue;
129 			}
130 			if (usb_endpoint_dir_in(&e->desc)) {
131 				if (!intr && !in)
132 					in = e;
133 				else if (intr && !status)
134 					status = e;
135 			} else {
136 				if (!out)
137 					out = e;
138 			}
139 		}
140 		if (in && out)
141 			break;
142 	}
143 	if (!alt || !in || !out)
144 		return -EINVAL;
145 
146 	if (alt->desc.bAlternateSetting != 0 ||
147 	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
148 		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
149 				alt->desc.bAlternateSetting);
150 		if (tmp < 0)
151 			return tmp;
152 	}
153 
154 	dev->in = usb_rcvbulkpipe (dev->udev,
155 			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
156 	dev->out = usb_sndbulkpipe (dev->udev,
157 			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
158 	dev->status = status;
159 	return 0;
160 }
161 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
162 
163 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
164 {
165 	int 		tmp, i;
166 	unsigned char	buf [13];
167 
168 	tmp = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
169 	if (tmp != 12) {
170 		dev_dbg(&dev->udev->dev,
171 			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
172 		if (tmp >= 0)
173 			tmp = -EINVAL;
174 		return tmp;
175 	}
176 	for (i = tmp = 0; i < 6; i++, tmp += 2)
177 		dev->net->dev_addr [i] =
178 			(hex_to_bin(buf[tmp]) << 4) + hex_to_bin(buf[tmp + 1]);
179 	return 0;
180 }
181 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
182 
183 static void intr_complete (struct urb *urb)
184 {
185 	struct usbnet	*dev = urb->context;
186 	int		status = urb->status;
187 
188 	switch (status) {
189 	/* success */
190 	case 0:
191 		dev->driver_info->status(dev, urb);
192 		break;
193 
194 	/* software-driven interface shutdown */
195 	case -ENOENT:		/* urb killed */
196 	case -ESHUTDOWN:	/* hardware gone */
197 		netif_dbg(dev, ifdown, dev->net,
198 			  "intr shutdown, code %d\n", status);
199 		return;
200 
201 	/* NOTE:  not throttling like RX/TX, since this endpoint
202 	 * already polls infrequently
203 	 */
204 	default:
205 		netdev_dbg(dev->net, "intr status %d\n", status);
206 		break;
207 	}
208 
209 	if (!netif_running (dev->net))
210 		return;
211 
212 	status = usb_submit_urb (urb, GFP_ATOMIC);
213 	if (status != 0)
214 		netif_err(dev, timer, dev->net,
215 			  "intr resubmit --> %d\n", status);
216 }
217 
218 static int init_status (struct usbnet *dev, struct usb_interface *intf)
219 {
220 	char		*buf = NULL;
221 	unsigned	pipe = 0;
222 	unsigned	maxp;
223 	unsigned	period;
224 
225 	if (!dev->driver_info->status)
226 		return 0;
227 
228 	pipe = usb_rcvintpipe (dev->udev,
229 			dev->status->desc.bEndpointAddress
230 				& USB_ENDPOINT_NUMBER_MASK);
231 	maxp = usb_maxpacket (dev->udev, pipe, 0);
232 
233 	/* avoid 1 msec chatter:  min 8 msec poll rate */
234 	period = max ((int) dev->status->desc.bInterval,
235 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
236 
237 	buf = kmalloc (maxp, GFP_KERNEL);
238 	if (buf) {
239 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
240 		if (!dev->interrupt) {
241 			kfree (buf);
242 			return -ENOMEM;
243 		} else {
244 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
245 				buf, maxp, intr_complete, dev, period);
246 			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
247 			dev_dbg(&intf->dev,
248 				"status ep%din, %d bytes period %d\n",
249 				usb_pipeendpoint(pipe), maxp, period);
250 		}
251 	}
252 	return 0;
253 }
254 
255 /* Passes this packet up the stack, updating its accounting.
256  * Some link protocols batch packets, so their rx_fixup paths
257  * can return clones as well as just modify the original skb.
258  */
259 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
260 {
261 	int	status;
262 
263 	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
264 		skb_queue_tail(&dev->rxq_pause, skb);
265 		return;
266 	}
267 
268 	skb->protocol = eth_type_trans (skb, dev->net);
269 	dev->net->stats.rx_packets++;
270 	dev->net->stats.rx_bytes += skb->len;
271 
272 	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
273 		  skb->len + sizeof (struct ethhdr), skb->protocol);
274 	memset (skb->cb, 0, sizeof (struct skb_data));
275 
276 	if (skb_defer_rx_timestamp(skb))
277 		return;
278 
279 	status = netif_rx (skb);
280 	if (status != NET_RX_SUCCESS)
281 		netif_dbg(dev, rx_err, dev->net,
282 			  "netif_rx status %d\n", status);
283 }
284 EXPORT_SYMBOL_GPL(usbnet_skb_return);
285 
286 
287 /*-------------------------------------------------------------------------
288  *
289  * Network Device Driver (peer link to "Host Device", from USB host)
290  *
291  *-------------------------------------------------------------------------*/
292 
293 int usbnet_change_mtu (struct net_device *net, int new_mtu)
294 {
295 	struct usbnet	*dev = netdev_priv(net);
296 	int		ll_mtu = new_mtu + net->hard_header_len;
297 	int		old_hard_mtu = dev->hard_mtu;
298 	int		old_rx_urb_size = dev->rx_urb_size;
299 
300 	if (new_mtu <= 0)
301 		return -EINVAL;
302 	// no second zero-length packet read wanted after mtu-sized packets
303 	if ((ll_mtu % dev->maxpacket) == 0)
304 		return -EDOM;
305 	net->mtu = new_mtu;
306 
307 	dev->hard_mtu = net->mtu + net->hard_header_len;
308 	if (dev->rx_urb_size == old_hard_mtu) {
309 		dev->rx_urb_size = dev->hard_mtu;
310 		if (dev->rx_urb_size > old_rx_urb_size)
311 			usbnet_unlink_rx_urbs(dev);
312 	}
313 
314 	return 0;
315 }
316 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
317 
318 /* The caller must hold list->lock */
319 static void __usbnet_queue_skb(struct sk_buff_head *list,
320 			struct sk_buff *newsk, enum skb_state state)
321 {
322 	struct skb_data *entry = (struct skb_data *) newsk->cb;
323 
324 	__skb_queue_tail(list, newsk);
325 	entry->state = state;
326 }
327 
328 /*-------------------------------------------------------------------------*/
329 
330 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
331  * completion callbacks.  2.5 should have fixed those bugs...
332  */
333 
334 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
335 		struct sk_buff_head *list, enum skb_state state)
336 {
337 	unsigned long		flags;
338 	enum skb_state 		old_state;
339 	struct skb_data *entry = (struct skb_data *) skb->cb;
340 
341 	spin_lock_irqsave(&list->lock, flags);
342 	old_state = entry->state;
343 	entry->state = state;
344 	__skb_unlink(skb, list);
345 	spin_unlock(&list->lock);
346 	spin_lock(&dev->done.lock);
347 	__skb_queue_tail(&dev->done, skb);
348 	if (dev->done.qlen == 1)
349 		tasklet_schedule(&dev->bh);
350 	spin_unlock_irqrestore(&dev->done.lock, flags);
351 	return old_state;
352 }
353 
354 /* some work can't be done in tasklets, so we use keventd
355  *
356  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
357  * but tasklet_schedule() doesn't.  hope the failure is rare.
358  */
359 void usbnet_defer_kevent (struct usbnet *dev, int work)
360 {
361 	set_bit (work, &dev->flags);
362 	if (!schedule_work (&dev->kevent)) {
363 		if (net_ratelimit())
364 			netdev_err(dev->net, "kevent %d may have been dropped\n", work);
365 	} else {
366 		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
367 	}
368 }
369 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
370 
371 /*-------------------------------------------------------------------------*/
372 
373 static void rx_complete (struct urb *urb);
374 
375 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
376 {
377 	struct sk_buff		*skb;
378 	struct skb_data		*entry;
379 	int			retval = 0;
380 	unsigned long		lockflags;
381 	size_t			size = dev->rx_urb_size;
382 
383 	skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
384 	if (!skb) {
385 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
386 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
387 		usb_free_urb (urb);
388 		return -ENOMEM;
389 	}
390 
391 	entry = (struct skb_data *) skb->cb;
392 	entry->urb = urb;
393 	entry->dev = dev;
394 	entry->length = 0;
395 
396 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
397 		skb->data, size, rx_complete, skb);
398 
399 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
400 
401 	if (netif_running (dev->net) &&
402 	    netif_device_present (dev->net) &&
403 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
404 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
405 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
406 		case -EPIPE:
407 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
408 			break;
409 		case -ENOMEM:
410 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
411 			break;
412 		case -ENODEV:
413 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
414 			netif_device_detach (dev->net);
415 			break;
416 		case -EHOSTUNREACH:
417 			retval = -ENOLINK;
418 			break;
419 		default:
420 			netif_dbg(dev, rx_err, dev->net,
421 				  "rx submit, %d\n", retval);
422 			tasklet_schedule (&dev->bh);
423 			break;
424 		case 0:
425 			__usbnet_queue_skb(&dev->rxq, skb, rx_start);
426 		}
427 	} else {
428 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
429 		retval = -ENOLINK;
430 	}
431 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
432 	if (retval) {
433 		dev_kfree_skb_any (skb);
434 		usb_free_urb (urb);
435 	}
436 	return retval;
437 }
438 
439 
440 /*-------------------------------------------------------------------------*/
441 
442 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
443 {
444 	if (dev->driver_info->rx_fixup &&
445 	    !dev->driver_info->rx_fixup (dev, skb)) {
446 		/* With RX_ASSEMBLE, rx_fixup() must update counters */
447 		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
448 			dev->net->stats.rx_errors++;
449 		goto done;
450 	}
451 	// else network stack removes extra byte if we forced a short packet
452 
453 	if (skb->len) {
454 		/* all data was already cloned from skb inside the driver */
455 		if (dev->driver_info->flags & FLAG_MULTI_PACKET)
456 			dev_kfree_skb_any(skb);
457 		else
458 			usbnet_skb_return(dev, skb);
459 		return;
460 	}
461 
462 	netif_dbg(dev, rx_err, dev->net, "drop\n");
463 	dev->net->stats.rx_errors++;
464 done:
465 	skb_queue_tail(&dev->done, skb);
466 }
467 
468 /*-------------------------------------------------------------------------*/
469 
470 static void rx_complete (struct urb *urb)
471 {
472 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
473 	struct skb_data		*entry = (struct skb_data *) skb->cb;
474 	struct usbnet		*dev = entry->dev;
475 	int			urb_status = urb->status;
476 	enum skb_state		state;
477 
478 	skb_put (skb, urb->actual_length);
479 	state = rx_done;
480 	entry->urb = NULL;
481 
482 	switch (urb_status) {
483 	/* success */
484 	case 0:
485 		if (skb->len < dev->net->hard_header_len) {
486 			state = rx_cleanup;
487 			dev->net->stats.rx_errors++;
488 			dev->net->stats.rx_length_errors++;
489 			netif_dbg(dev, rx_err, dev->net,
490 				  "rx length %d\n", skb->len);
491 		}
492 		break;
493 
494 	/* stalls need manual reset. this is rare ... except that
495 	 * when going through USB 2.0 TTs, unplug appears this way.
496 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
497 	 * storm, recovering as needed.
498 	 */
499 	case -EPIPE:
500 		dev->net->stats.rx_errors++;
501 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
502 		// FALLTHROUGH
503 
504 	/* software-driven interface shutdown */
505 	case -ECONNRESET:		/* async unlink */
506 	case -ESHUTDOWN:		/* hardware gone */
507 		netif_dbg(dev, ifdown, dev->net,
508 			  "rx shutdown, code %d\n", urb_status);
509 		goto block;
510 
511 	/* we get controller i/o faults during khubd disconnect() delays.
512 	 * throttle down resubmits, to avoid log floods; just temporarily,
513 	 * so we still recover when the fault isn't a khubd delay.
514 	 */
515 	case -EPROTO:
516 	case -ETIME:
517 	case -EILSEQ:
518 		dev->net->stats.rx_errors++;
519 		if (!timer_pending (&dev->delay)) {
520 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
521 			netif_dbg(dev, link, dev->net,
522 				  "rx throttle %d\n", urb_status);
523 		}
524 block:
525 		state = rx_cleanup;
526 		entry->urb = urb;
527 		urb = NULL;
528 		break;
529 
530 	/* data overrun ... flush fifo? */
531 	case -EOVERFLOW:
532 		dev->net->stats.rx_over_errors++;
533 		// FALLTHROUGH
534 
535 	default:
536 		state = rx_cleanup;
537 		dev->net->stats.rx_errors++;
538 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
539 		break;
540 	}
541 
542 	state = defer_bh(dev, skb, &dev->rxq, state);
543 
544 	if (urb) {
545 		if (netif_running (dev->net) &&
546 		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
547 		    state != unlink_start) {
548 			rx_submit (dev, urb, GFP_ATOMIC);
549 			usb_mark_last_busy(dev->udev);
550 			return;
551 		}
552 		usb_free_urb (urb);
553 	}
554 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
555 }
556 
557 /*-------------------------------------------------------------------------*/
558 void usbnet_pause_rx(struct usbnet *dev)
559 {
560 	set_bit(EVENT_RX_PAUSED, &dev->flags);
561 
562 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
563 }
564 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
565 
566 void usbnet_resume_rx(struct usbnet *dev)
567 {
568 	struct sk_buff *skb;
569 	int num = 0;
570 
571 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
572 
573 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
574 		usbnet_skb_return(dev, skb);
575 		num++;
576 	}
577 
578 	tasklet_schedule(&dev->bh);
579 
580 	netif_dbg(dev, rx_status, dev->net,
581 		  "paused rx queue disabled, %d skbs requeued\n", num);
582 }
583 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
584 
585 void usbnet_purge_paused_rxq(struct usbnet *dev)
586 {
587 	skb_queue_purge(&dev->rxq_pause);
588 }
589 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
590 
591 /*-------------------------------------------------------------------------*/
592 
593 // unlink pending rx/tx; completion handlers do all other cleanup
594 
595 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
596 {
597 	unsigned long		flags;
598 	struct sk_buff		*skb;
599 	int			count = 0;
600 
601 	spin_lock_irqsave (&q->lock, flags);
602 	while (!skb_queue_empty(q)) {
603 		struct skb_data		*entry;
604 		struct urb		*urb;
605 		int			retval;
606 
607 		skb_queue_walk(q, skb) {
608 			entry = (struct skb_data *) skb->cb;
609 			if (entry->state != unlink_start)
610 				goto found;
611 		}
612 		break;
613 found:
614 		entry->state = unlink_start;
615 		urb = entry->urb;
616 
617 		/*
618 		 * Get reference count of the URB to avoid it to be
619 		 * freed during usb_unlink_urb, which may trigger
620 		 * use-after-free problem inside usb_unlink_urb since
621 		 * usb_unlink_urb is always racing with .complete
622 		 * handler(include defer_bh).
623 		 */
624 		usb_get_urb(urb);
625 		spin_unlock_irqrestore(&q->lock, flags);
626 		// during some PM-driven resume scenarios,
627 		// these (async) unlinks complete immediately
628 		retval = usb_unlink_urb (urb);
629 		if (retval != -EINPROGRESS && retval != 0)
630 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
631 		else
632 			count++;
633 		usb_put_urb(urb);
634 		spin_lock_irqsave(&q->lock, flags);
635 	}
636 	spin_unlock_irqrestore (&q->lock, flags);
637 	return count;
638 }
639 
640 // Flush all pending rx urbs
641 // minidrivers may need to do this when the MTU changes
642 
643 void usbnet_unlink_rx_urbs(struct usbnet *dev)
644 {
645 	if (netif_running(dev->net)) {
646 		(void) unlink_urbs (dev, &dev->rxq);
647 		tasklet_schedule(&dev->bh);
648 	}
649 }
650 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
651 
652 /*-------------------------------------------------------------------------*/
653 
654 // precondition: never called in_interrupt
655 static void usbnet_terminate_urbs(struct usbnet *dev)
656 {
657 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
658 	DECLARE_WAITQUEUE(wait, current);
659 	int temp;
660 
661 	/* ensure there are no more active urbs */
662 	add_wait_queue(&unlink_wakeup, &wait);
663 	set_current_state(TASK_UNINTERRUPTIBLE);
664 	dev->wait = &unlink_wakeup;
665 	temp = unlink_urbs(dev, &dev->txq) +
666 		unlink_urbs(dev, &dev->rxq);
667 
668 	/* maybe wait for deletions to finish. */
669 	while (!skb_queue_empty(&dev->rxq)
670 		&& !skb_queue_empty(&dev->txq)
671 		&& !skb_queue_empty(&dev->done)) {
672 			schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
673 			set_current_state(TASK_UNINTERRUPTIBLE);
674 			netif_dbg(dev, ifdown, dev->net,
675 				  "waited for %d urb completions\n", temp);
676 	}
677 	set_current_state(TASK_RUNNING);
678 	dev->wait = NULL;
679 	remove_wait_queue(&unlink_wakeup, &wait);
680 }
681 
682 int usbnet_stop (struct net_device *net)
683 {
684 	struct usbnet		*dev = netdev_priv(net);
685 	struct driver_info	*info = dev->driver_info;
686 	int			retval;
687 
688 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
689 	netif_stop_queue (net);
690 
691 	netif_info(dev, ifdown, dev->net,
692 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
693 		   net->stats.rx_packets, net->stats.tx_packets,
694 		   net->stats.rx_errors, net->stats.tx_errors);
695 
696 	/* allow minidriver to stop correctly (wireless devices to turn off
697 	 * radio etc) */
698 	if (info->stop) {
699 		retval = info->stop(dev);
700 		if (retval < 0)
701 			netif_info(dev, ifdown, dev->net,
702 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
703 				   retval,
704 				   dev->udev->bus->bus_name, dev->udev->devpath,
705 				   info->description);
706 	}
707 
708 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
709 		usbnet_terminate_urbs(dev);
710 
711 	usb_kill_urb(dev->interrupt);
712 
713 	usbnet_purge_paused_rxq(dev);
714 
715 	/* deferred work (task, timer, softirq) must also stop.
716 	 * can't flush_scheduled_work() until we drop rtnl (later),
717 	 * else workers could deadlock; so make workers a NOP.
718 	 */
719 	dev->flags = 0;
720 	del_timer_sync (&dev->delay);
721 	tasklet_kill (&dev->bh);
722 	if (info->manage_power &&
723 	    !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags))
724 		info->manage_power(dev, 0);
725 	else
726 		usb_autopm_put_interface(dev->intf);
727 
728 	return 0;
729 }
730 EXPORT_SYMBOL_GPL(usbnet_stop);
731 
732 /*-------------------------------------------------------------------------*/
733 
734 // posts reads, and enables write queuing
735 
736 // precondition: never called in_interrupt
737 
738 int usbnet_open (struct net_device *net)
739 {
740 	struct usbnet		*dev = netdev_priv(net);
741 	int			retval;
742 	struct driver_info	*info = dev->driver_info;
743 
744 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
745 		netif_info(dev, ifup, dev->net,
746 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
747 			   retval,
748 			   dev->udev->bus->bus_name,
749 			   dev->udev->devpath,
750 			   info->description);
751 		goto done_nopm;
752 	}
753 
754 	// put into "known safe" state
755 	if (info->reset && (retval = info->reset (dev)) < 0) {
756 		netif_info(dev, ifup, dev->net,
757 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
758 			   retval,
759 			   dev->udev->bus->bus_name,
760 			   dev->udev->devpath,
761 			   info->description);
762 		goto done;
763 	}
764 
765 	// insist peer be connected
766 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
767 		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
768 		goto done;
769 	}
770 
771 	/* start any status interrupt transfer */
772 	if (dev->interrupt) {
773 		retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
774 		if (retval < 0) {
775 			netif_err(dev, ifup, dev->net,
776 				  "intr submit %d\n", retval);
777 			goto done;
778 		}
779 	}
780 
781 	set_bit(EVENT_DEV_OPEN, &dev->flags);
782 	netif_start_queue (net);
783 	netif_info(dev, ifup, dev->net,
784 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
785 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
786 		   dev->net->mtu,
787 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
788 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
789 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
790 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
791 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
792 		   "simple");
793 
794 	// delay posting reads until we're fully open
795 	tasklet_schedule (&dev->bh);
796 	if (info->manage_power) {
797 		retval = info->manage_power(dev, 1);
798 		if (retval < 0) {
799 			retval = 0;
800 			set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
801 		} else {
802 			usb_autopm_put_interface(dev->intf);
803 		}
804 	}
805 	return retval;
806 done:
807 	usb_autopm_put_interface(dev->intf);
808 done_nopm:
809 	return retval;
810 }
811 EXPORT_SYMBOL_GPL(usbnet_open);
812 
813 /*-------------------------------------------------------------------------*/
814 
815 /* ethtool methods; minidrivers may need to add some more, but
816  * they'll probably want to use this base set.
817  */
818 
819 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
820 {
821 	struct usbnet *dev = netdev_priv(net);
822 
823 	if (!dev->mii.mdio_read)
824 		return -EOPNOTSUPP;
825 
826 	return mii_ethtool_gset(&dev->mii, cmd);
827 }
828 EXPORT_SYMBOL_GPL(usbnet_get_settings);
829 
830 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
831 {
832 	struct usbnet *dev = netdev_priv(net);
833 	int retval;
834 
835 	if (!dev->mii.mdio_write)
836 		return -EOPNOTSUPP;
837 
838 	retval = mii_ethtool_sset(&dev->mii, cmd);
839 
840 	/* link speed/duplex might have changed */
841 	if (dev->driver_info->link_reset)
842 		dev->driver_info->link_reset(dev);
843 
844 	return retval;
845 
846 }
847 EXPORT_SYMBOL_GPL(usbnet_set_settings);
848 
849 u32 usbnet_get_link (struct net_device *net)
850 {
851 	struct usbnet *dev = netdev_priv(net);
852 
853 	/* If a check_connect is defined, return its result */
854 	if (dev->driver_info->check_connect)
855 		return dev->driver_info->check_connect (dev) == 0;
856 
857 	/* if the device has mii operations, use those */
858 	if (dev->mii.mdio_read)
859 		return mii_link_ok(&dev->mii);
860 
861 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
862 	return ethtool_op_get_link(net);
863 }
864 EXPORT_SYMBOL_GPL(usbnet_get_link);
865 
866 int usbnet_nway_reset(struct net_device *net)
867 {
868 	struct usbnet *dev = netdev_priv(net);
869 
870 	if (!dev->mii.mdio_write)
871 		return -EOPNOTSUPP;
872 
873 	return mii_nway_restart(&dev->mii);
874 }
875 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
876 
877 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
878 {
879 	struct usbnet *dev = netdev_priv(net);
880 
881 	strlcpy (info->driver, dev->driver_name, sizeof info->driver);
882 	strlcpy (info->version, DRIVER_VERSION, sizeof info->version);
883 	strlcpy (info->fw_version, dev->driver_info->description,
884 		sizeof info->fw_version);
885 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
886 }
887 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
888 
889 u32 usbnet_get_msglevel (struct net_device *net)
890 {
891 	struct usbnet *dev = netdev_priv(net);
892 
893 	return dev->msg_enable;
894 }
895 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
896 
897 void usbnet_set_msglevel (struct net_device *net, u32 level)
898 {
899 	struct usbnet *dev = netdev_priv(net);
900 
901 	dev->msg_enable = level;
902 }
903 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
904 
905 /* drivers may override default ethtool_ops in their bind() routine */
906 static const struct ethtool_ops usbnet_ethtool_ops = {
907 	.get_settings		= usbnet_get_settings,
908 	.set_settings		= usbnet_set_settings,
909 	.get_link		= usbnet_get_link,
910 	.nway_reset		= usbnet_nway_reset,
911 	.get_drvinfo		= usbnet_get_drvinfo,
912 	.get_msglevel		= usbnet_get_msglevel,
913 	.set_msglevel		= usbnet_set_msglevel,
914 	.get_ts_info		= ethtool_op_get_ts_info,
915 };
916 
917 /*-------------------------------------------------------------------------*/
918 
919 /* work that cannot be done in interrupt context uses keventd.
920  *
921  * NOTE:  with 2.5 we could do more of this using completion callbacks,
922  * especially now that control transfers can be queued.
923  */
924 static void
925 kevent (struct work_struct *work)
926 {
927 	struct usbnet		*dev =
928 		container_of(work, struct usbnet, kevent);
929 	int			status;
930 
931 	/* usb_clear_halt() needs a thread context */
932 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
933 		unlink_urbs (dev, &dev->txq);
934 		status = usb_autopm_get_interface(dev->intf);
935 		if (status < 0)
936 			goto fail_pipe;
937 		status = usb_clear_halt (dev->udev, dev->out);
938 		usb_autopm_put_interface(dev->intf);
939 		if (status < 0 &&
940 		    status != -EPIPE &&
941 		    status != -ESHUTDOWN) {
942 			if (netif_msg_tx_err (dev))
943 fail_pipe:
944 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
945 					   status);
946 		} else {
947 			clear_bit (EVENT_TX_HALT, &dev->flags);
948 			if (status != -ESHUTDOWN)
949 				netif_wake_queue (dev->net);
950 		}
951 	}
952 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
953 		unlink_urbs (dev, &dev->rxq);
954 		status = usb_autopm_get_interface(dev->intf);
955 		if (status < 0)
956 			goto fail_halt;
957 		status = usb_clear_halt (dev->udev, dev->in);
958 		usb_autopm_put_interface(dev->intf);
959 		if (status < 0 &&
960 		    status != -EPIPE &&
961 		    status != -ESHUTDOWN) {
962 			if (netif_msg_rx_err (dev))
963 fail_halt:
964 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
965 					   status);
966 		} else {
967 			clear_bit (EVENT_RX_HALT, &dev->flags);
968 			tasklet_schedule (&dev->bh);
969 		}
970 	}
971 
972 	/* tasklet could resubmit itself forever if memory is tight */
973 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
974 		struct urb	*urb = NULL;
975 		int resched = 1;
976 
977 		if (netif_running (dev->net))
978 			urb = usb_alloc_urb (0, GFP_KERNEL);
979 		else
980 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
981 		if (urb != NULL) {
982 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
983 			status = usb_autopm_get_interface(dev->intf);
984 			if (status < 0) {
985 				usb_free_urb(urb);
986 				goto fail_lowmem;
987 			}
988 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
989 				resched = 0;
990 			usb_autopm_put_interface(dev->intf);
991 fail_lowmem:
992 			if (resched)
993 				tasklet_schedule (&dev->bh);
994 		}
995 	}
996 
997 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
998 		struct driver_info	*info = dev->driver_info;
999 		int			retval = 0;
1000 
1001 		clear_bit (EVENT_LINK_RESET, &dev->flags);
1002 		status = usb_autopm_get_interface(dev->intf);
1003 		if (status < 0)
1004 			goto skip_reset;
1005 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1006 			usb_autopm_put_interface(dev->intf);
1007 skip_reset:
1008 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1009 				    retval,
1010 				    dev->udev->bus->bus_name,
1011 				    dev->udev->devpath,
1012 				    info->description);
1013 		} else {
1014 			usb_autopm_put_interface(dev->intf);
1015 		}
1016 	}
1017 
1018 	if (dev->flags)
1019 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1020 }
1021 
1022 /*-------------------------------------------------------------------------*/
1023 
1024 static void tx_complete (struct urb *urb)
1025 {
1026 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1027 	struct skb_data		*entry = (struct skb_data *) skb->cb;
1028 	struct usbnet		*dev = entry->dev;
1029 
1030 	if (urb->status == 0) {
1031 		if (!(dev->driver_info->flags & FLAG_MULTI_PACKET))
1032 			dev->net->stats.tx_packets++;
1033 		dev->net->stats.tx_bytes += entry->length;
1034 	} else {
1035 		dev->net->stats.tx_errors++;
1036 
1037 		switch (urb->status) {
1038 		case -EPIPE:
1039 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1040 			break;
1041 
1042 		/* software-driven interface shutdown */
1043 		case -ECONNRESET:		// async unlink
1044 		case -ESHUTDOWN:		// hardware gone
1045 			break;
1046 
1047 		// like rx, tx gets controller i/o faults during khubd delays
1048 		// and so it uses the same throttling mechanism.
1049 		case -EPROTO:
1050 		case -ETIME:
1051 		case -EILSEQ:
1052 			usb_mark_last_busy(dev->udev);
1053 			if (!timer_pending (&dev->delay)) {
1054 				mod_timer (&dev->delay,
1055 					jiffies + THROTTLE_JIFFIES);
1056 				netif_dbg(dev, link, dev->net,
1057 					  "tx throttle %d\n", urb->status);
1058 			}
1059 			netif_stop_queue (dev->net);
1060 			break;
1061 		default:
1062 			netif_dbg(dev, tx_err, dev->net,
1063 				  "tx err %d\n", entry->urb->status);
1064 			break;
1065 		}
1066 	}
1067 
1068 	usb_autopm_put_interface_async(dev->intf);
1069 	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1070 }
1071 
1072 /*-------------------------------------------------------------------------*/
1073 
1074 void usbnet_tx_timeout (struct net_device *net)
1075 {
1076 	struct usbnet		*dev = netdev_priv(net);
1077 
1078 	unlink_urbs (dev, &dev->txq);
1079 	tasklet_schedule (&dev->bh);
1080 
1081 	// FIXME: device recovery -- reset?
1082 }
1083 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1084 
1085 /*-------------------------------------------------------------------------*/
1086 
1087 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1088 				     struct net_device *net)
1089 {
1090 	struct usbnet		*dev = netdev_priv(net);
1091 	int			length;
1092 	struct urb		*urb = NULL;
1093 	struct skb_data		*entry;
1094 	struct driver_info	*info = dev->driver_info;
1095 	unsigned long		flags;
1096 	int retval;
1097 
1098 	if (skb)
1099 		skb_tx_timestamp(skb);
1100 
1101 	// some devices want funky USB-level framing, for
1102 	// win32 driver (usually) and/or hardware quirks
1103 	if (info->tx_fixup) {
1104 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1105 		if (!skb) {
1106 			if (netif_msg_tx_err(dev)) {
1107 				netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1108 				goto drop;
1109 			} else {
1110 				/* cdc_ncm collected packet; waits for more */
1111 				goto not_drop;
1112 			}
1113 		}
1114 	}
1115 	length = skb->len;
1116 
1117 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1118 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1119 		goto drop;
1120 	}
1121 
1122 	entry = (struct skb_data *) skb->cb;
1123 	entry->urb = urb;
1124 	entry->dev = dev;
1125 	entry->length = length;
1126 
1127 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1128 			skb->data, skb->len, tx_complete, skb);
1129 
1130 	/* don't assume the hardware handles USB_ZERO_PACKET
1131 	 * NOTE:  strictly conforming cdc-ether devices should expect
1132 	 * the ZLP here, but ignore the one-byte packet.
1133 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1134 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1135 	 * packet itself if needed.
1136 	 */
1137 	if (length % dev->maxpacket == 0) {
1138 		if (!(info->flags & FLAG_SEND_ZLP)) {
1139 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1140 				urb->transfer_buffer_length++;
1141 				if (skb_tailroom(skb)) {
1142 					skb->data[skb->len] = 0;
1143 					__skb_put(skb, 1);
1144 				}
1145 			}
1146 		} else
1147 			urb->transfer_flags |= URB_ZERO_PACKET;
1148 	}
1149 
1150 	spin_lock_irqsave(&dev->txq.lock, flags);
1151 	retval = usb_autopm_get_interface_async(dev->intf);
1152 	if (retval < 0) {
1153 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1154 		goto drop;
1155 	}
1156 
1157 #ifdef CONFIG_PM
1158 	/* if this triggers the device is still a sleep */
1159 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1160 		/* transmission will be done in resume */
1161 		usb_anchor_urb(urb, &dev->deferred);
1162 		/* no use to process more packets */
1163 		netif_stop_queue(net);
1164 		usb_put_urb(urb);
1165 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1166 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1167 		goto deferred;
1168 	}
1169 #endif
1170 
1171 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1172 	case -EPIPE:
1173 		netif_stop_queue (net);
1174 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1175 		usb_autopm_put_interface_async(dev->intf);
1176 		break;
1177 	default:
1178 		usb_autopm_put_interface_async(dev->intf);
1179 		netif_dbg(dev, tx_err, dev->net,
1180 			  "tx: submit urb err %d\n", retval);
1181 		break;
1182 	case 0:
1183 		net->trans_start = jiffies;
1184 		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1185 		if (dev->txq.qlen >= TX_QLEN (dev))
1186 			netif_stop_queue (net);
1187 	}
1188 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1189 
1190 	if (retval) {
1191 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1192 drop:
1193 		dev->net->stats.tx_dropped++;
1194 not_drop:
1195 		if (skb)
1196 			dev_kfree_skb_any (skb);
1197 		usb_free_urb (urb);
1198 	} else
1199 		netif_dbg(dev, tx_queued, dev->net,
1200 			  "> tx, len %d, type 0x%x\n", length, skb->protocol);
1201 #ifdef CONFIG_PM
1202 deferred:
1203 #endif
1204 	return NETDEV_TX_OK;
1205 }
1206 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1207 
1208 static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1209 {
1210 	struct urb	*urb;
1211 	int		i;
1212 	int		ret = 0;
1213 
1214 	/* don't refill the queue all at once */
1215 	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1216 		urb = usb_alloc_urb(0, flags);
1217 		if (urb != NULL) {
1218 			ret = rx_submit(dev, urb, flags);
1219 			if (ret)
1220 				goto err;
1221 		} else {
1222 			ret = -ENOMEM;
1223 			goto err;
1224 		}
1225 	}
1226 err:
1227 	return ret;
1228 }
1229 
1230 /*-------------------------------------------------------------------------*/
1231 
1232 // tasklet (work deferred from completions, in_irq) or timer
1233 
1234 static void usbnet_bh (unsigned long param)
1235 {
1236 	struct usbnet		*dev = (struct usbnet *) param;
1237 	struct sk_buff		*skb;
1238 	struct skb_data		*entry;
1239 
1240 	while ((skb = skb_dequeue (&dev->done))) {
1241 		entry = (struct skb_data *) skb->cb;
1242 		switch (entry->state) {
1243 		case rx_done:
1244 			entry->state = rx_cleanup;
1245 			rx_process (dev, skb);
1246 			continue;
1247 		case tx_done:
1248 		case rx_cleanup:
1249 			usb_free_urb (entry->urb);
1250 			dev_kfree_skb (skb);
1251 			continue;
1252 		default:
1253 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1254 		}
1255 	}
1256 
1257 	// waiting for all pending urbs to complete?
1258 	if (dev->wait) {
1259 		if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
1260 			wake_up (dev->wait);
1261 		}
1262 
1263 	// or are we maybe short a few urbs?
1264 	} else if (netif_running (dev->net) &&
1265 		   netif_device_present (dev->net) &&
1266 		   !timer_pending (&dev->delay) &&
1267 		   !test_bit (EVENT_RX_HALT, &dev->flags)) {
1268 		int	temp = dev->rxq.qlen;
1269 
1270 		if (temp < RX_QLEN(dev)) {
1271 			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1272 				return;
1273 			if (temp != dev->rxq.qlen)
1274 				netif_dbg(dev, link, dev->net,
1275 					  "rxqlen %d --> %d\n",
1276 					  temp, dev->rxq.qlen);
1277 			if (dev->rxq.qlen < RX_QLEN(dev))
1278 				tasklet_schedule (&dev->bh);
1279 		}
1280 		if (dev->txq.qlen < TX_QLEN (dev))
1281 			netif_wake_queue (dev->net);
1282 	}
1283 }
1284 
1285 
1286 /*-------------------------------------------------------------------------
1287  *
1288  * USB Device Driver support
1289  *
1290  *-------------------------------------------------------------------------*/
1291 
1292 // precondition: never called in_interrupt
1293 
1294 void usbnet_disconnect (struct usb_interface *intf)
1295 {
1296 	struct usbnet		*dev;
1297 	struct usb_device	*xdev;
1298 	struct net_device	*net;
1299 
1300 	dev = usb_get_intfdata(intf);
1301 	usb_set_intfdata(intf, NULL);
1302 	if (!dev)
1303 		return;
1304 
1305 	xdev = interface_to_usbdev (intf);
1306 
1307 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1308 		   intf->dev.driver->name,
1309 		   xdev->bus->bus_name, xdev->devpath,
1310 		   dev->driver_info->description);
1311 
1312 	net = dev->net;
1313 	unregister_netdev (net);
1314 
1315 	cancel_work_sync(&dev->kevent);
1316 
1317 	usb_scuttle_anchored_urbs(&dev->deferred);
1318 
1319 	if (dev->driver_info->unbind)
1320 		dev->driver_info->unbind (dev, intf);
1321 
1322 	usb_kill_urb(dev->interrupt);
1323 	usb_free_urb(dev->interrupt);
1324 
1325 	free_netdev(net);
1326 }
1327 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1328 
1329 static const struct net_device_ops usbnet_netdev_ops = {
1330 	.ndo_open		= usbnet_open,
1331 	.ndo_stop		= usbnet_stop,
1332 	.ndo_start_xmit		= usbnet_start_xmit,
1333 	.ndo_tx_timeout		= usbnet_tx_timeout,
1334 	.ndo_change_mtu		= usbnet_change_mtu,
1335 	.ndo_set_mac_address 	= eth_mac_addr,
1336 	.ndo_validate_addr	= eth_validate_addr,
1337 };
1338 
1339 /*-------------------------------------------------------------------------*/
1340 
1341 // precondition: never called in_interrupt
1342 
1343 static struct device_type wlan_type = {
1344 	.name	= "wlan",
1345 };
1346 
1347 static struct device_type wwan_type = {
1348 	.name	= "wwan",
1349 };
1350 
1351 int
1352 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1353 {
1354 	struct usbnet			*dev;
1355 	struct net_device		*net;
1356 	struct usb_host_interface	*interface;
1357 	struct driver_info		*info;
1358 	struct usb_device		*xdev;
1359 	int				status;
1360 	const char			*name;
1361 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1362 
1363 	/* usbnet already took usb runtime pm, so have to enable the feature
1364 	 * for usb interface, otherwise usb_autopm_get_interface may return
1365 	 * failure if USB_SUSPEND(RUNTIME_PM) is enabled.
1366 	 */
1367 	if (!driver->supports_autosuspend) {
1368 		driver->supports_autosuspend = 1;
1369 		pm_runtime_enable(&udev->dev);
1370 	}
1371 
1372 	name = udev->dev.driver->name;
1373 	info = (struct driver_info *) prod->driver_info;
1374 	if (!info) {
1375 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1376 		return -ENODEV;
1377 	}
1378 	xdev = interface_to_usbdev (udev);
1379 	interface = udev->cur_altsetting;
1380 
1381 	status = -ENOMEM;
1382 
1383 	// set up our own records
1384 	net = alloc_etherdev(sizeof(*dev));
1385 	if (!net)
1386 		goto out;
1387 
1388 	/* netdev_printk() needs this so do it as early as possible */
1389 	SET_NETDEV_DEV(net, &udev->dev);
1390 
1391 	dev = netdev_priv(net);
1392 	dev->udev = xdev;
1393 	dev->intf = udev;
1394 	dev->driver_info = info;
1395 	dev->driver_name = name;
1396 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1397 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1398 	skb_queue_head_init (&dev->rxq);
1399 	skb_queue_head_init (&dev->txq);
1400 	skb_queue_head_init (&dev->done);
1401 	skb_queue_head_init(&dev->rxq_pause);
1402 	dev->bh.func = usbnet_bh;
1403 	dev->bh.data = (unsigned long) dev;
1404 	INIT_WORK (&dev->kevent, kevent);
1405 	init_usb_anchor(&dev->deferred);
1406 	dev->delay.function = usbnet_bh;
1407 	dev->delay.data = (unsigned long) dev;
1408 	init_timer (&dev->delay);
1409 	mutex_init (&dev->phy_mutex);
1410 
1411 	dev->net = net;
1412 	strcpy (net->name, "usb%d");
1413 	memcpy (net->dev_addr, node_id, sizeof node_id);
1414 
1415 	/* rx and tx sides can use different message sizes;
1416 	 * bind() should set rx_urb_size in that case.
1417 	 */
1418 	dev->hard_mtu = net->mtu + net->hard_header_len;
1419 #if 0
1420 // dma_supported() is deeply broken on almost all architectures
1421 	// possible with some EHCI controllers
1422 	if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1423 		net->features |= NETIF_F_HIGHDMA;
1424 #endif
1425 
1426 	net->netdev_ops = &usbnet_netdev_ops;
1427 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1428 	net->ethtool_ops = &usbnet_ethtool_ops;
1429 
1430 	// allow device-specific bind/init procedures
1431 	// NOTE net->name still not usable ...
1432 	if (info->bind) {
1433 		status = info->bind (dev, udev);
1434 		if (status < 0)
1435 			goto out1;
1436 
1437 		// heuristic:  "usb%d" for links we know are two-host,
1438 		// else "eth%d" when there's reasonable doubt.  userspace
1439 		// can rename the link if it knows better.
1440 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1441 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1442 		     (net->dev_addr [0] & 0x02) == 0))
1443 			strcpy (net->name, "eth%d");
1444 		/* WLAN devices should always be named "wlan%d" */
1445 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1446 			strcpy(net->name, "wlan%d");
1447 		/* WWAN devices should always be named "wwan%d" */
1448 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1449 			strcpy(net->name, "wwan%d");
1450 
1451 		/* maybe the remote can't receive an Ethernet MTU */
1452 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1453 			net->mtu = dev->hard_mtu - net->hard_header_len;
1454 	} else if (!info->in || !info->out)
1455 		status = usbnet_get_endpoints (dev, udev);
1456 	else {
1457 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1458 		dev->out = usb_sndbulkpipe (xdev, info->out);
1459 		if (!(info->flags & FLAG_NO_SETINT))
1460 			status = usb_set_interface (xdev,
1461 				interface->desc.bInterfaceNumber,
1462 				interface->desc.bAlternateSetting);
1463 		else
1464 			status = 0;
1465 
1466 	}
1467 	if (status >= 0 && dev->status)
1468 		status = init_status (dev, udev);
1469 	if (status < 0)
1470 		goto out3;
1471 
1472 	if (!dev->rx_urb_size)
1473 		dev->rx_urb_size = dev->hard_mtu;
1474 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1475 
1476 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1477 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1478 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1479 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1480 
1481 	status = register_netdev (net);
1482 	if (status)
1483 		goto out4;
1484 	netif_info(dev, probe, dev->net,
1485 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1486 		   udev->dev.driver->name,
1487 		   xdev->bus->bus_name, xdev->devpath,
1488 		   dev->driver_info->description,
1489 		   net->dev_addr);
1490 
1491 	// ok, it's ready to go.
1492 	usb_set_intfdata (udev, dev);
1493 
1494 	netif_device_attach (net);
1495 
1496 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1497 		netif_carrier_off(net);
1498 
1499 	return 0;
1500 
1501 out4:
1502 	usb_free_urb(dev->interrupt);
1503 out3:
1504 	if (info->unbind)
1505 		info->unbind (dev, udev);
1506 out1:
1507 	free_netdev(net);
1508 out:
1509 	return status;
1510 }
1511 EXPORT_SYMBOL_GPL(usbnet_probe);
1512 
1513 /*-------------------------------------------------------------------------*/
1514 
1515 /*
1516  * suspend the whole driver as soon as the first interface is suspended
1517  * resume only when the last interface is resumed
1518  */
1519 
1520 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1521 {
1522 	struct usbnet		*dev = usb_get_intfdata(intf);
1523 
1524 	if (!dev->suspend_count++) {
1525 		spin_lock_irq(&dev->txq.lock);
1526 		/* don't autosuspend while transmitting */
1527 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1528 			dev->suspend_count--;
1529 			spin_unlock_irq(&dev->txq.lock);
1530 			return -EBUSY;
1531 		} else {
1532 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1533 			spin_unlock_irq(&dev->txq.lock);
1534 		}
1535 		/*
1536 		 * accelerate emptying of the rx and queues, to avoid
1537 		 * having everything error out.
1538 		 */
1539 		netif_device_detach (dev->net);
1540 		usbnet_terminate_urbs(dev);
1541 		usb_kill_urb(dev->interrupt);
1542 
1543 		/*
1544 		 * reattach so runtime management can use and
1545 		 * wake the device
1546 		 */
1547 		netif_device_attach (dev->net);
1548 	}
1549 	return 0;
1550 }
1551 EXPORT_SYMBOL_GPL(usbnet_suspend);
1552 
1553 int usbnet_resume (struct usb_interface *intf)
1554 {
1555 	struct usbnet		*dev = usb_get_intfdata(intf);
1556 	struct sk_buff          *skb;
1557 	struct urb              *res;
1558 	int                     retval;
1559 
1560 	if (!--dev->suspend_count) {
1561 		/* resume interrupt URBs */
1562 		if (dev->interrupt && test_bit(EVENT_DEV_OPEN, &dev->flags))
1563 			usb_submit_urb(dev->interrupt, GFP_NOIO);
1564 
1565 		spin_lock_irq(&dev->txq.lock);
1566 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1567 
1568 			skb = (struct sk_buff *)res->context;
1569 			retval = usb_submit_urb(res, GFP_ATOMIC);
1570 			if (retval < 0) {
1571 				dev_kfree_skb_any(skb);
1572 				usb_free_urb(res);
1573 				usb_autopm_put_interface_async(dev->intf);
1574 			} else {
1575 				dev->net->trans_start = jiffies;
1576 				__skb_queue_tail(&dev->txq, skb);
1577 			}
1578 		}
1579 
1580 		smp_mb();
1581 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1582 		spin_unlock_irq(&dev->txq.lock);
1583 
1584 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1585 			/* handle remote wakeup ASAP */
1586 			if (!dev->wait &&
1587 				netif_device_present(dev->net) &&
1588 				!timer_pending(&dev->delay) &&
1589 				!test_bit(EVENT_RX_HALT, &dev->flags))
1590 					rx_alloc_submit(dev, GFP_NOIO);
1591 
1592 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1593 				netif_tx_wake_all_queues(dev->net);
1594 			tasklet_schedule (&dev->bh);
1595 		}
1596 	}
1597 
1598 	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1599 		usb_autopm_get_interface_no_resume(intf);
1600 
1601 	return 0;
1602 }
1603 EXPORT_SYMBOL_GPL(usbnet_resume);
1604 
1605 /*
1606  * Either a subdriver implements manage_power, then it is assumed to always
1607  * be ready to be suspended or it reports the readiness to be suspended
1608  * explicitly
1609  */
1610 void usbnet_device_suggests_idle(struct usbnet *dev)
1611 {
1612 	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1613 		dev->intf->needs_remote_wakeup = 1;
1614 		usb_autopm_put_interface_async(dev->intf);
1615 	}
1616 }
1617 EXPORT_SYMBOL(usbnet_device_suggests_idle);
1618 
1619 /*
1620  * For devices that can do without special commands
1621  */
1622 int usbnet_manage_power(struct usbnet *dev, int on)
1623 {
1624 	dev->intf->needs_remote_wakeup = on;
1625 	return 0;
1626 }
1627 EXPORT_SYMBOL(usbnet_manage_power);
1628 
1629 /*-------------------------------------------------------------------------*/
1630 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1631 			     u16 value, u16 index, void *data, u16 size)
1632 {
1633 	void *buf = NULL;
1634 	int err = -ENOMEM;
1635 
1636 	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
1637 		   " value=0x%04x index=0x%04x size=%d\n",
1638 		   cmd, reqtype, value, index, size);
1639 
1640 	if (data) {
1641 		buf = kmalloc(size, GFP_KERNEL);
1642 		if (!buf)
1643 			goto out;
1644 	}
1645 
1646 	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
1647 			      cmd, reqtype, value, index, buf, size,
1648 			      USB_CTRL_GET_TIMEOUT);
1649 	if (err > 0 && err <= size)
1650 		memcpy(data, buf, err);
1651 	kfree(buf);
1652 out:
1653 	return err;
1654 }
1655 
1656 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1657 			      u16 value, u16 index, const void *data,
1658 			      u16 size)
1659 {
1660 	void *buf = NULL;
1661 	int err = -ENOMEM;
1662 
1663 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
1664 		   " value=0x%04x index=0x%04x size=%d\n",
1665 		   cmd, reqtype, value, index, size);
1666 
1667 	if (data) {
1668 		buf = kmemdup(data, size, GFP_KERNEL);
1669 		if (!buf)
1670 			goto out;
1671 	}
1672 
1673 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
1674 			      cmd, reqtype, value, index, buf, size,
1675 			      USB_CTRL_SET_TIMEOUT);
1676 	kfree(buf);
1677 
1678 out:
1679 	return err;
1680 }
1681 
1682 /*
1683  * The function can't be called inside suspend/resume callback,
1684  * otherwise deadlock will be caused.
1685  */
1686 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1687 		    u16 value, u16 index, void *data, u16 size)
1688 {
1689 	int ret;
1690 
1691 	if (usb_autopm_get_interface(dev->intf) < 0)
1692 		return -ENODEV;
1693 	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
1694 				data, size);
1695 	usb_autopm_put_interface(dev->intf);
1696 	return ret;
1697 }
1698 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
1699 
1700 /*
1701  * The function can't be called inside suspend/resume callback,
1702  * otherwise deadlock will be caused.
1703  */
1704 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1705 		     u16 value, u16 index, const void *data, u16 size)
1706 {
1707 	int ret;
1708 
1709 	if (usb_autopm_get_interface(dev->intf) < 0)
1710 		return -ENODEV;
1711 	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
1712 				 data, size);
1713 	usb_autopm_put_interface(dev->intf);
1714 	return ret;
1715 }
1716 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
1717 
1718 /*
1719  * The function can be called inside suspend/resume callback safely
1720  * and should only be called by suspend/resume callback generally.
1721  */
1722 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
1723 			  u16 value, u16 index, void *data, u16 size)
1724 {
1725 	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
1726 				 data, size);
1727 }
1728 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
1729 
1730 /*
1731  * The function can be called inside suspend/resume callback safely
1732  * and should only be called by suspend/resume callback generally.
1733  */
1734 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
1735 			  u16 value, u16 index, const void *data,
1736 			  u16 size)
1737 {
1738 	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
1739 				  data, size);
1740 }
1741 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
1742 
1743 static void usbnet_async_cmd_cb(struct urb *urb)
1744 {
1745 	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
1746 	int status = urb->status;
1747 
1748 	if (status < 0)
1749 		dev_dbg(&urb->dev->dev, "%s failed with %d",
1750 			__func__, status);
1751 
1752 	kfree(req);
1753 	usb_free_urb(urb);
1754 }
1755 
1756 /*
1757  * The caller must make sure that device can't be put into suspend
1758  * state until the control URB completes.
1759  */
1760 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
1761 			   u16 value, u16 index, const void *data, u16 size)
1762 {
1763 	struct usb_ctrlrequest *req = NULL;
1764 	struct urb *urb;
1765 	int err = -ENOMEM;
1766 	void *buf = NULL;
1767 
1768 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
1769 		   " value=0x%04x index=0x%04x size=%d\n",
1770 		   cmd, reqtype, value, index, size);
1771 
1772 	urb = usb_alloc_urb(0, GFP_ATOMIC);
1773 	if (!urb) {
1774 		netdev_err(dev->net, "Error allocating URB in"
1775 			   " %s!\n", __func__);
1776 		goto fail;
1777 	}
1778 
1779 	if (data) {
1780 		buf = kmemdup(data, size, GFP_ATOMIC);
1781 		if (!buf) {
1782 			netdev_err(dev->net, "Error allocating buffer"
1783 				   " in %s!\n", __func__);
1784 			goto fail_free;
1785 		}
1786 	}
1787 
1788 	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
1789 	if (!req) {
1790 		netdev_err(dev->net, "Failed to allocate memory for %s\n",
1791 			   __func__);
1792 		goto fail_free_buf;
1793 	}
1794 
1795 	req->bRequestType = reqtype;
1796 	req->bRequest = cmd;
1797 	req->wValue = cpu_to_le16(value);
1798 	req->wIndex = cpu_to_le16(index);
1799 	req->wLength = cpu_to_le16(size);
1800 
1801 	usb_fill_control_urb(urb, dev->udev,
1802 			     usb_sndctrlpipe(dev->udev, 0),
1803 			     (void *)req, buf, size,
1804 			     usbnet_async_cmd_cb, req);
1805 	urb->transfer_flags |= URB_FREE_BUFFER;
1806 
1807 	err = usb_submit_urb(urb, GFP_ATOMIC);
1808 	if (err < 0) {
1809 		netdev_err(dev->net, "Error submitting the control"
1810 			   " message: status=%d\n", err);
1811 		goto fail_free;
1812 	}
1813 	return 0;
1814 
1815 fail_free_buf:
1816 	kfree(buf);
1817 fail_free:
1818 	kfree(req);
1819 	usb_free_urb(urb);
1820 fail:
1821 	return err;
1822 
1823 }
1824 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
1825 /*-------------------------------------------------------------------------*/
1826 
1827 static int __init usbnet_init(void)
1828 {
1829 	/* Compiler should optimize this out. */
1830 	BUILD_BUG_ON(
1831 		FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
1832 
1833 	eth_random_addr(node_id);
1834 	return 0;
1835 }
1836 module_init(usbnet_init);
1837 
1838 static void __exit usbnet_exit(void)
1839 {
1840 }
1841 module_exit(usbnet_exit);
1842 
1843 MODULE_AUTHOR("David Brownell");
1844 MODULE_DESCRIPTION("USB network driver framework");
1845 MODULE_LICENSE("GPL");
1846