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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 */
usbnet_get_endpoints(struct usbnet * dev,struct usb_interface * intf)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 
usbnet_get_ethernet_addr(struct usbnet * dev,int iMACAddress)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 
init_status(struct usbnet * dev,struct usb_interface * intf)185 static int init_status (struct usbnet *dev, struct usb_interface *intf)
186 {
187 	char		*buf = NULL;
188 	unsigned	pipe = 0;
189 	unsigned	maxp;
190 	unsigned	period;
191 
192 	if (!dev->driver_info->status)
193 		return 0;
194 
195 	pipe = usb_rcvintpipe (dev->udev,
196 			dev->status->desc.bEndpointAddress
197 				& USB_ENDPOINT_NUMBER_MASK);
198 	maxp = usb_maxpacket (dev->udev, pipe, 0);
199 
200 	/* avoid 1 msec chatter:  min 8 msec poll rate */
201 	period = max ((int) dev->status->desc.bInterval,
202 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
203 
204 	buf = kmalloc (maxp, GFP_KERNEL);
205 	if (buf) {
206 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
207 		if (!dev->interrupt) {
208 			kfree (buf);
209 			return -ENOMEM;
210 		} else {
211 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
212 				buf, maxp, intr_complete, dev, period);
213 			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
214 			dev_dbg(&intf->dev,
215 				"status ep%din, %d bytes period %d\n",
216 				usb_pipeendpoint(pipe), maxp, period);
217 		}
218 	}
219 	return 0;
220 }
221 
222 /* Passes this packet up the stack, updating its accounting.
223  * Some link protocols batch packets, so their rx_fixup paths
224  * can return clones as well as just modify the original skb.
225  */
usbnet_skb_return(struct usbnet * dev,struct sk_buff * skb)226 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
227 {
228 	int	status;
229 
230 	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
231 		skb_queue_tail(&dev->rxq_pause, skb);
232 		return;
233 	}
234 
235 	skb->protocol = eth_type_trans (skb, dev->net);
236 	dev->net->stats.rx_packets++;
237 	dev->net->stats.rx_bytes += skb->len;
238 
239 	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
240 		  skb->len + sizeof (struct ethhdr), skb->protocol);
241 	memset (skb->cb, 0, sizeof (struct skb_data));
242 
243 	if (skb_defer_rx_timestamp(skb))
244 		return;
245 
246 	status = netif_rx (skb);
247 	if (status != NET_RX_SUCCESS)
248 		netif_dbg(dev, rx_err, dev->net,
249 			  "netif_rx status %d\n", status);
250 }
251 EXPORT_SYMBOL_GPL(usbnet_skb_return);
252 
253 
254 /*-------------------------------------------------------------------------
255  *
256  * Network Device Driver (peer link to "Host Device", from USB host)
257  *
258  *-------------------------------------------------------------------------*/
259 
usbnet_change_mtu(struct net_device * net,int new_mtu)260 int usbnet_change_mtu (struct net_device *net, int new_mtu)
261 {
262 	struct usbnet	*dev = netdev_priv(net);
263 	int		ll_mtu = new_mtu + net->hard_header_len;
264 	int		old_hard_mtu = dev->hard_mtu;
265 	int		old_rx_urb_size = dev->rx_urb_size;
266 
267 	if (new_mtu <= 0)
268 		return -EINVAL;
269 	// no second zero-length packet read wanted after mtu-sized packets
270 	if ((ll_mtu % dev->maxpacket) == 0)
271 		return -EDOM;
272 	net->mtu = new_mtu;
273 
274 	dev->hard_mtu = net->mtu + net->hard_header_len;
275 	if (dev->rx_urb_size == old_hard_mtu) {
276 		dev->rx_urb_size = dev->hard_mtu;
277 		if (dev->rx_urb_size > old_rx_urb_size)
278 			usbnet_unlink_rx_urbs(dev);
279 	}
280 
281 	return 0;
282 }
283 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
284 
285 /* The caller must hold list->lock */
__usbnet_queue_skb(struct sk_buff_head * list,struct sk_buff * newsk,enum skb_state state)286 static void __usbnet_queue_skb(struct sk_buff_head *list,
287 			struct sk_buff *newsk, enum skb_state state)
288 {
289 	struct skb_data *entry = (struct skb_data *) newsk->cb;
290 
291 	__skb_queue_tail(list, newsk);
292 	entry->state = state;
293 }
294 
295 /*-------------------------------------------------------------------------*/
296 
297 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
298  * completion callbacks.  2.5 should have fixed those bugs...
299  */
300 
defer_bh(struct usbnet * dev,struct sk_buff * skb,struct sk_buff_head * list,enum skb_state state)301 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
302 		struct sk_buff_head *list, enum skb_state state)
303 {
304 	unsigned long		flags;
305 	enum skb_state 		old_state;
306 	struct skb_data *entry = (struct skb_data *) skb->cb;
307 
308 	spin_lock_irqsave(&list->lock, flags);
309 	old_state = entry->state;
310 	entry->state = state;
311 	__skb_unlink(skb, list);
312 	spin_unlock(&list->lock);
313 	spin_lock(&dev->done.lock);
314 	__skb_queue_tail(&dev->done, skb);
315 	if (dev->done.qlen == 1)
316 		tasklet_schedule(&dev->bh);
317 	spin_unlock_irqrestore(&dev->done.lock, flags);
318 	return old_state;
319 }
320 
321 /* some work can't be done in tasklets, so we use keventd
322  *
323  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
324  * but tasklet_schedule() doesn't.  hope the failure is rare.
325  */
usbnet_defer_kevent(struct usbnet * dev,int work)326 void usbnet_defer_kevent (struct usbnet *dev, int work)
327 {
328 	set_bit (work, &dev->flags);
329 	if (!schedule_work (&dev->kevent))
330 		netdev_err(dev->net, "kevent %d may have been dropped\n", work);
331 	else
332 		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
333 }
334 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
335 
336 /*-------------------------------------------------------------------------*/
337 
338 static void rx_complete (struct urb *urb);
339 
rx_submit(struct usbnet * dev,struct urb * urb,gfp_t flags)340 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
341 {
342 	struct sk_buff		*skb;
343 	struct skb_data		*entry;
344 	int			retval = 0;
345 	unsigned long		lockflags;
346 	size_t			size = dev->rx_urb_size;
347 
348 	skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
349 	if (!skb) {
350 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
351 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
352 		usb_free_urb (urb);
353 		return -ENOMEM;
354 	}
355 
356 	entry = (struct skb_data *) skb->cb;
357 	entry->urb = urb;
358 	entry->dev = dev;
359 	entry->length = 0;
360 
361 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
362 		skb->data, size, rx_complete, skb);
363 
364 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
365 
366 	if (netif_running (dev->net) &&
367 	    netif_device_present (dev->net) &&
368 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
369 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
370 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
371 		case -EPIPE:
372 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
373 			break;
374 		case -ENOMEM:
375 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
376 			break;
377 		case -ENODEV:
378 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
379 			netif_device_detach (dev->net);
380 			break;
381 		case -EHOSTUNREACH:
382 			retval = -ENOLINK;
383 			break;
384 		default:
385 			netif_dbg(dev, rx_err, dev->net,
386 				  "rx submit, %d\n", retval);
387 			tasklet_schedule (&dev->bh);
388 			break;
389 		case 0:
390 			__usbnet_queue_skb(&dev->rxq, skb, rx_start);
391 		}
392 	} else {
393 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
394 		retval = -ENOLINK;
395 	}
396 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
397 	if (retval) {
398 		dev_kfree_skb_any (skb);
399 		usb_free_urb (urb);
400 	}
401 	return retval;
402 }
403 
404 
405 /*-------------------------------------------------------------------------*/
406 
rx_process(struct usbnet * dev,struct sk_buff * skb)407 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
408 {
409 	if (dev->driver_info->rx_fixup &&
410 	    !dev->driver_info->rx_fixup (dev, skb)) {
411 		/* With RX_ASSEMBLE, rx_fixup() must update counters */
412 		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
413 			dev->net->stats.rx_errors++;
414 		goto done;
415 	}
416 	// else network stack removes extra byte if we forced a short packet
417 
418 	if (skb->len) {
419 		/* all data was already cloned from skb inside the driver */
420 		if (dev->driver_info->flags & FLAG_MULTI_PACKET)
421 			dev_kfree_skb_any(skb);
422 		else
423 			usbnet_skb_return(dev, skb);
424 		return;
425 	}
426 
427 	netif_dbg(dev, rx_err, dev->net, "drop\n");
428 	dev->net->stats.rx_errors++;
429 done:
430 	skb_queue_tail(&dev->done, skb);
431 }
432 
433 /*-------------------------------------------------------------------------*/
434 
rx_complete(struct urb * urb)435 static void rx_complete (struct urb *urb)
436 {
437 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
438 	struct skb_data		*entry = (struct skb_data *) skb->cb;
439 	struct usbnet		*dev = entry->dev;
440 	int			urb_status = urb->status;
441 	enum skb_state		state;
442 
443 	skb_put (skb, urb->actual_length);
444 	state = rx_done;
445 	entry->urb = NULL;
446 
447 	switch (urb_status) {
448 	/* success */
449 	case 0:
450 		if (skb->len < dev->net->hard_header_len) {
451 			state = rx_cleanup;
452 			dev->net->stats.rx_errors++;
453 			dev->net->stats.rx_length_errors++;
454 			netif_dbg(dev, rx_err, dev->net,
455 				  "rx length %d\n", skb->len);
456 		}
457 		break;
458 
459 	/* stalls need manual reset. this is rare ... except that
460 	 * when going through USB 2.0 TTs, unplug appears this way.
461 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
462 	 * storm, recovering as needed.
463 	 */
464 	case -EPIPE:
465 		dev->net->stats.rx_errors++;
466 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
467 		// FALLTHROUGH
468 
469 	/* software-driven interface shutdown */
470 	case -ECONNRESET:		/* async unlink */
471 	case -ESHUTDOWN:		/* hardware gone */
472 		netif_dbg(dev, ifdown, dev->net,
473 			  "rx shutdown, code %d\n", urb_status);
474 		goto block;
475 
476 	/* we get controller i/o faults during khubd disconnect() delays.
477 	 * throttle down resubmits, to avoid log floods; just temporarily,
478 	 * so we still recover when the fault isn't a khubd delay.
479 	 */
480 	case -EPROTO:
481 	case -ETIME:
482 	case -EILSEQ:
483 		dev->net->stats.rx_errors++;
484 		if (!timer_pending (&dev->delay)) {
485 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
486 			netif_dbg(dev, link, dev->net,
487 				  "rx throttle %d\n", urb_status);
488 		}
489 block:
490 		state = rx_cleanup;
491 		entry->urb = urb;
492 		urb = NULL;
493 		break;
494 
495 	/* data overrun ... flush fifo? */
496 	case -EOVERFLOW:
497 		dev->net->stats.rx_over_errors++;
498 		// FALLTHROUGH
499 
500 	default:
501 		state = rx_cleanup;
502 		dev->net->stats.rx_errors++;
503 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
504 		break;
505 	}
506 
507 	state = defer_bh(dev, skb, &dev->rxq, state);
508 
509 	if (urb) {
510 		if (netif_running (dev->net) &&
511 		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
512 		    state != unlink_start) {
513 			rx_submit (dev, urb, GFP_ATOMIC);
514 			usb_mark_last_busy(dev->udev);
515 			return;
516 		}
517 		usb_free_urb (urb);
518 	}
519 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
520 }
521 
intr_complete(struct urb * urb)522 static void intr_complete (struct urb *urb)
523 {
524 	struct usbnet	*dev = urb->context;
525 	int		status = urb->status;
526 
527 	switch (status) {
528 	/* success */
529 	case 0:
530 		dev->driver_info->status(dev, urb);
531 		break;
532 
533 	/* software-driven interface shutdown */
534 	case -ENOENT:		/* urb killed */
535 	case -ESHUTDOWN:	/* hardware gone */
536 		netif_dbg(dev, ifdown, dev->net,
537 			  "intr shutdown, code %d\n", status);
538 		return;
539 
540 	/* NOTE:  not throttling like RX/TX, since this endpoint
541 	 * already polls infrequently
542 	 */
543 	default:
544 		netdev_dbg(dev->net, "intr status %d\n", status);
545 		break;
546 	}
547 
548 	if (!netif_running (dev->net))
549 		return;
550 
551 	memset(urb->transfer_buffer, 0, urb->transfer_buffer_length);
552 	status = usb_submit_urb (urb, GFP_ATOMIC);
553 	if (status != 0)
554 		netif_err(dev, timer, dev->net,
555 			  "intr resubmit --> %d\n", status);
556 }
557 
558 /*-------------------------------------------------------------------------*/
usbnet_pause_rx(struct usbnet * dev)559 void usbnet_pause_rx(struct usbnet *dev)
560 {
561 	set_bit(EVENT_RX_PAUSED, &dev->flags);
562 
563 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
564 }
565 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
566 
usbnet_resume_rx(struct usbnet * dev)567 void usbnet_resume_rx(struct usbnet *dev)
568 {
569 	struct sk_buff *skb;
570 	int num = 0;
571 
572 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
573 
574 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
575 		usbnet_skb_return(dev, skb);
576 		num++;
577 	}
578 
579 	tasklet_schedule(&dev->bh);
580 
581 	netif_dbg(dev, rx_status, dev->net,
582 		  "paused rx queue disabled, %d skbs requeued\n", num);
583 }
584 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
585 
usbnet_purge_paused_rxq(struct usbnet * dev)586 void usbnet_purge_paused_rxq(struct usbnet *dev)
587 {
588 	skb_queue_purge(&dev->rxq_pause);
589 }
590 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
591 
592 /*-------------------------------------------------------------------------*/
593 
594 // unlink pending rx/tx; completion handlers do all other cleanup
595 
unlink_urbs(struct usbnet * dev,struct sk_buff_head * q)596 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
597 {
598 	unsigned long		flags;
599 	struct sk_buff		*skb;
600 	int			count = 0;
601 
602 	spin_lock_irqsave (&q->lock, flags);
603 	while (!skb_queue_empty(q)) {
604 		struct skb_data		*entry;
605 		struct urb		*urb;
606 		int			retval;
607 
608 		skb_queue_walk(q, skb) {
609 			entry = (struct skb_data *) skb->cb;
610 			if (entry->state != unlink_start)
611 				goto found;
612 		}
613 		break;
614 found:
615 		entry->state = unlink_start;
616 		urb = entry->urb;
617 
618 		/*
619 		 * Get reference count of the URB to avoid it to be
620 		 * freed during usb_unlink_urb, which may trigger
621 		 * use-after-free problem inside usb_unlink_urb since
622 		 * usb_unlink_urb is always racing with .complete
623 		 * handler(include defer_bh).
624 		 */
625 		usb_get_urb(urb);
626 		spin_unlock_irqrestore(&q->lock, flags);
627 		// during some PM-driven resume scenarios,
628 		// these (async) unlinks complete immediately
629 		retval = usb_unlink_urb (urb);
630 		if (retval != -EINPROGRESS && retval != 0)
631 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
632 		else
633 			count++;
634 		usb_put_urb(urb);
635 		spin_lock_irqsave(&q->lock, flags);
636 	}
637 	spin_unlock_irqrestore (&q->lock, flags);
638 	return count;
639 }
640 
641 // Flush all pending rx urbs
642 // minidrivers may need to do this when the MTU changes
643 
usbnet_unlink_rx_urbs(struct usbnet * dev)644 void usbnet_unlink_rx_urbs(struct usbnet *dev)
645 {
646 	if (netif_running(dev->net)) {
647 		(void) unlink_urbs (dev, &dev->rxq);
648 		tasklet_schedule(&dev->bh);
649 	}
650 }
651 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
652 
653 /*-------------------------------------------------------------------------*/
654 
655 // precondition: never called in_interrupt
usbnet_terminate_urbs(struct usbnet * dev)656 static void usbnet_terminate_urbs(struct usbnet *dev)
657 {
658 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
659 	DECLARE_WAITQUEUE(wait, current);
660 	int temp;
661 
662 	/* ensure there are no more active urbs */
663 	add_wait_queue(&unlink_wakeup, &wait);
664 	set_current_state(TASK_UNINTERRUPTIBLE);
665 	dev->wait = &unlink_wakeup;
666 	temp = unlink_urbs(dev, &dev->txq) +
667 		unlink_urbs(dev, &dev->rxq);
668 
669 	/* maybe wait for deletions to finish. */
670 	while (!skb_queue_empty(&dev->rxq)
671 		&& !skb_queue_empty(&dev->txq)
672 		&& !skb_queue_empty(&dev->done)) {
673 			schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
674 			set_current_state(TASK_UNINTERRUPTIBLE);
675 			netif_dbg(dev, ifdown, dev->net,
676 				  "waited for %d urb completions\n", temp);
677 	}
678 	set_current_state(TASK_RUNNING);
679 	dev->wait = NULL;
680 	remove_wait_queue(&unlink_wakeup, &wait);
681 }
682 
usbnet_stop(struct net_device * net)683 int usbnet_stop (struct net_device *net)
684 {
685 	struct usbnet		*dev = netdev_priv(net);
686 	struct driver_info	*info = dev->driver_info;
687 	int			retval;
688 
689 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
690 	netif_stop_queue (net);
691 
692 	netif_info(dev, ifdown, dev->net,
693 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
694 		   net->stats.rx_packets, net->stats.tx_packets,
695 		   net->stats.rx_errors, net->stats.tx_errors);
696 
697 	/* allow minidriver to stop correctly (wireless devices to turn off
698 	 * radio etc) */
699 	if (info->stop) {
700 		retval = info->stop(dev);
701 		if (retval < 0)
702 			netif_info(dev, ifdown, dev->net,
703 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
704 				   retval,
705 				   dev->udev->bus->bus_name, dev->udev->devpath,
706 				   info->description);
707 	}
708 
709 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
710 		usbnet_terminate_urbs(dev);
711 
712 	usb_kill_urb(dev->interrupt);
713 
714 	usbnet_purge_paused_rxq(dev);
715 
716 	/* deferred work (task, timer, softirq) must also stop.
717 	 * can't flush_scheduled_work() until we drop rtnl (later),
718 	 * else workers could deadlock; so make workers a NOP.
719 	 */
720 	dev->flags = 0;
721 	del_timer_sync (&dev->delay);
722 	tasklet_kill (&dev->bh);
723 	if (info->manage_power)
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 
usbnet_open(struct net_device * net)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 			goto done;
800 		usb_autopm_put_interface(dev->intf);
801 	}
802 	return retval;
803 
804 done:
805 	usb_autopm_put_interface(dev->intf);
806 done_nopm:
807 	return retval;
808 }
809 EXPORT_SYMBOL_GPL(usbnet_open);
810 
811 /*-------------------------------------------------------------------------*/
812 
813 /* ethtool methods; minidrivers may need to add some more, but
814  * they'll probably want to use this base set.
815  */
816 
usbnet_get_settings(struct net_device * net,struct ethtool_cmd * cmd)817 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
818 {
819 	struct usbnet *dev = netdev_priv(net);
820 
821 	if (!dev->mii.mdio_read)
822 		return -EOPNOTSUPP;
823 
824 	return mii_ethtool_gset(&dev->mii, cmd);
825 }
826 EXPORT_SYMBOL_GPL(usbnet_get_settings);
827 
usbnet_set_settings(struct net_device * net,struct ethtool_cmd * cmd)828 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
829 {
830 	struct usbnet *dev = netdev_priv(net);
831 	int retval;
832 
833 	if (!dev->mii.mdio_write)
834 		return -EOPNOTSUPP;
835 
836 	retval = mii_ethtool_sset(&dev->mii, cmd);
837 
838 	/* link speed/duplex might have changed */
839 	if (dev->driver_info->link_reset)
840 		dev->driver_info->link_reset(dev);
841 
842 	return retval;
843 
844 }
845 EXPORT_SYMBOL_GPL(usbnet_set_settings);
846 
usbnet_get_link(struct net_device * net)847 u32 usbnet_get_link (struct net_device *net)
848 {
849 	struct usbnet *dev = netdev_priv(net);
850 
851 	/* If a check_connect is defined, return its result */
852 	if (dev->driver_info->check_connect)
853 		return dev->driver_info->check_connect (dev) == 0;
854 
855 	/* if the device has mii operations, use those */
856 	if (dev->mii.mdio_read)
857 		return mii_link_ok(&dev->mii);
858 
859 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
860 	return ethtool_op_get_link(net);
861 }
862 EXPORT_SYMBOL_GPL(usbnet_get_link);
863 
usbnet_nway_reset(struct net_device * net)864 int usbnet_nway_reset(struct net_device *net)
865 {
866 	struct usbnet *dev = netdev_priv(net);
867 
868 	if (!dev->mii.mdio_write)
869 		return -EOPNOTSUPP;
870 
871 	return mii_nway_restart(&dev->mii);
872 }
873 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
874 
usbnet_get_drvinfo(struct net_device * net,struct ethtool_drvinfo * info)875 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
876 {
877 	struct usbnet *dev = netdev_priv(net);
878 
879 	strncpy (info->driver, dev->driver_name, sizeof info->driver);
880 	strncpy (info->version, DRIVER_VERSION, sizeof info->version);
881 	strncpy (info->fw_version, dev->driver_info->description,
882 		sizeof info->fw_version);
883 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
884 }
885 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
886 
usbnet_get_msglevel(struct net_device * net)887 u32 usbnet_get_msglevel (struct net_device *net)
888 {
889 	struct usbnet *dev = netdev_priv(net);
890 
891 	return dev->msg_enable;
892 }
893 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
894 
usbnet_set_msglevel(struct net_device * net,u32 level)895 void usbnet_set_msglevel (struct net_device *net, u32 level)
896 {
897 	struct usbnet *dev = netdev_priv(net);
898 
899 	dev->msg_enable = level;
900 }
901 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
902 
903 /* drivers may override default ethtool_ops in their bind() routine */
904 static const struct ethtool_ops usbnet_ethtool_ops = {
905 	.get_settings		= usbnet_get_settings,
906 	.set_settings		= usbnet_set_settings,
907 	.get_link		= usbnet_get_link,
908 	.nway_reset		= usbnet_nway_reset,
909 	.get_drvinfo		= usbnet_get_drvinfo,
910 	.get_msglevel		= usbnet_get_msglevel,
911 	.set_msglevel		= usbnet_set_msglevel,
912 };
913 
914 /*-------------------------------------------------------------------------*/
915 
916 /* work that cannot be done in interrupt context uses keventd.
917  *
918  * NOTE:  with 2.5 we could do more of this using completion callbacks,
919  * especially now that control transfers can be queued.
920  */
921 static void
kevent(struct work_struct * work)922 kevent (struct work_struct *work)
923 {
924 	struct usbnet		*dev =
925 		container_of(work, struct usbnet, kevent);
926 	int			status;
927 
928 	/* usb_clear_halt() needs a thread context */
929 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
930 		unlink_urbs (dev, &dev->txq);
931 		status = usb_autopm_get_interface(dev->intf);
932 		if (status < 0)
933 			goto fail_pipe;
934 		status = usb_clear_halt (dev->udev, dev->out);
935 		usb_autopm_put_interface(dev->intf);
936 		if (status < 0 &&
937 		    status != -EPIPE &&
938 		    status != -ESHUTDOWN) {
939 			if (netif_msg_tx_err (dev))
940 fail_pipe:
941 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
942 					   status);
943 		} else {
944 			clear_bit (EVENT_TX_HALT, &dev->flags);
945 			if (status != -ESHUTDOWN)
946 				netif_wake_queue (dev->net);
947 		}
948 	}
949 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
950 		unlink_urbs (dev, &dev->rxq);
951 		status = usb_autopm_get_interface(dev->intf);
952 		if (status < 0)
953 			goto fail_halt;
954 		status = usb_clear_halt (dev->udev, dev->in);
955 		usb_autopm_put_interface(dev->intf);
956 		if (status < 0 &&
957 		    status != -EPIPE &&
958 		    status != -ESHUTDOWN) {
959 			if (netif_msg_rx_err (dev))
960 fail_halt:
961 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
962 					   status);
963 		} else {
964 			clear_bit (EVENT_RX_HALT, &dev->flags);
965 			tasklet_schedule (&dev->bh);
966 		}
967 	}
968 
969 	/* tasklet could resubmit itself forever if memory is tight */
970 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
971 		struct urb	*urb = NULL;
972 		int resched = 1;
973 
974 		if (netif_running (dev->net))
975 			urb = usb_alloc_urb (0, GFP_KERNEL);
976 		else
977 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
978 		if (urb != NULL) {
979 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
980 			status = usb_autopm_get_interface(dev->intf);
981 			if (status < 0) {
982 				usb_free_urb(urb);
983 				goto fail_lowmem;
984 			}
985 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
986 				resched = 0;
987 			usb_autopm_put_interface(dev->intf);
988 fail_lowmem:
989 			if (resched)
990 				tasklet_schedule (&dev->bh);
991 		}
992 	}
993 
994 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
995 		struct driver_info	*info = dev->driver_info;
996 		int			retval = 0;
997 
998 		clear_bit (EVENT_LINK_RESET, &dev->flags);
999 		status = usb_autopm_get_interface(dev->intf);
1000 		if (status < 0)
1001 			goto skip_reset;
1002 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1003 			usb_autopm_put_interface(dev->intf);
1004 skip_reset:
1005 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1006 				    retval,
1007 				    dev->udev->bus->bus_name,
1008 				    dev->udev->devpath,
1009 				    info->description);
1010 		} else {
1011 			usb_autopm_put_interface(dev->intf);
1012 		}
1013 	}
1014 
1015 	if (dev->flags)
1016 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1017 }
1018 
1019 /*-------------------------------------------------------------------------*/
1020 
tx_complete(struct urb * urb)1021 static void tx_complete (struct urb *urb)
1022 {
1023 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1024 	struct skb_data		*entry = (struct skb_data *) skb->cb;
1025 	struct usbnet		*dev = entry->dev;
1026 
1027 	if (urb->status == 0) {
1028 		if (!(dev->driver_info->flags & FLAG_MULTI_PACKET))
1029 			dev->net->stats.tx_packets++;
1030 		dev->net->stats.tx_bytes += entry->length;
1031 	} else {
1032 		dev->net->stats.tx_errors++;
1033 
1034 		switch (urb->status) {
1035 		case -EPIPE:
1036 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1037 			break;
1038 
1039 		/* software-driven interface shutdown */
1040 		case -ECONNRESET:		// async unlink
1041 		case -ESHUTDOWN:		// hardware gone
1042 			break;
1043 
1044 		// like rx, tx gets controller i/o faults during khubd delays
1045 		// and so it uses the same throttling mechanism.
1046 		case -EPROTO:
1047 		case -ETIME:
1048 		case -EILSEQ:
1049 			usb_mark_last_busy(dev->udev);
1050 			if (!timer_pending (&dev->delay)) {
1051 				mod_timer (&dev->delay,
1052 					jiffies + THROTTLE_JIFFIES);
1053 				netif_dbg(dev, link, dev->net,
1054 					  "tx throttle %d\n", urb->status);
1055 			}
1056 			netif_stop_queue (dev->net);
1057 			break;
1058 		default:
1059 			netif_dbg(dev, tx_err, dev->net,
1060 				  "tx err %d\n", entry->urb->status);
1061 			break;
1062 		}
1063 	}
1064 
1065 	usb_autopm_put_interface_async(dev->intf);
1066 	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1067 }
1068 
1069 /*-------------------------------------------------------------------------*/
1070 
usbnet_tx_timeout(struct net_device * net)1071 void usbnet_tx_timeout (struct net_device *net)
1072 {
1073 	struct usbnet		*dev = netdev_priv(net);
1074 
1075 	unlink_urbs (dev, &dev->txq);
1076 	tasklet_schedule (&dev->bh);
1077 
1078 	// FIXME: device recovery -- reset?
1079 }
1080 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1081 
1082 /*-------------------------------------------------------------------------*/
1083 
usbnet_start_xmit(struct sk_buff * skb,struct net_device * net)1084 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1085 				     struct net_device *net)
1086 {
1087 	struct usbnet		*dev = netdev_priv(net);
1088 	int			length;
1089 	struct urb		*urb = NULL;
1090 	struct skb_data		*entry;
1091 	struct driver_info	*info = dev->driver_info;
1092 	unsigned long		flags;
1093 	int retval;
1094 
1095 	if (skb)
1096 		skb_tx_timestamp(skb);
1097 
1098 	// some devices want funky USB-level framing, for
1099 	// win32 driver (usually) and/or hardware quirks
1100 	if (info->tx_fixup) {
1101 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1102 		if (!skb) {
1103 			if (netif_msg_tx_err(dev)) {
1104 				netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1105 				goto drop;
1106 			} else {
1107 				/* cdc_ncm collected packet; waits for more */
1108 				goto not_drop;
1109 			}
1110 		}
1111 	}
1112 	length = skb->len;
1113 
1114 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1115 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1116 		goto drop;
1117 	}
1118 
1119 	entry = (struct skb_data *) skb->cb;
1120 	entry->urb = urb;
1121 	entry->dev = dev;
1122 	entry->length = length;
1123 
1124 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1125 			skb->data, skb->len, tx_complete, skb);
1126 
1127 	/* don't assume the hardware handles USB_ZERO_PACKET
1128 	 * NOTE:  strictly conforming cdc-ether devices should expect
1129 	 * the ZLP here, but ignore the one-byte packet.
1130 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1131 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1132 	 * packet itself if needed.
1133 	 */
1134 	if (length % dev->maxpacket == 0) {
1135 		if (!(info->flags & FLAG_SEND_ZLP)) {
1136 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1137 				urb->transfer_buffer_length++;
1138 				if (skb_tailroom(skb)) {
1139 					skb->data[skb->len] = 0;
1140 					__skb_put(skb, 1);
1141 				}
1142 			}
1143 		} else
1144 			urb->transfer_flags |= URB_ZERO_PACKET;
1145 	}
1146 
1147 	spin_lock_irqsave(&dev->txq.lock, flags);
1148 	retval = usb_autopm_get_interface_async(dev->intf);
1149 	if (retval < 0) {
1150 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1151 		goto drop;
1152 	}
1153 
1154 #ifdef CONFIG_PM
1155 	/* if this triggers the device is still a sleep */
1156 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1157 		/* transmission will be done in resume */
1158 		usb_anchor_urb(urb, &dev->deferred);
1159 		/* no use to process more packets */
1160 		netif_stop_queue(net);
1161 		usb_put_urb(urb);
1162 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1163 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1164 		goto deferred;
1165 	}
1166 #endif
1167 
1168 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1169 	case -EPIPE:
1170 		netif_stop_queue (net);
1171 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1172 		usb_autopm_put_interface_async(dev->intf);
1173 		break;
1174 	default:
1175 		usb_autopm_put_interface_async(dev->intf);
1176 		netif_dbg(dev, tx_err, dev->net,
1177 			  "tx: submit urb err %d\n", retval);
1178 		break;
1179 	case 0:
1180 		net->trans_start = jiffies;
1181 		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1182 		if (dev->txq.qlen >= TX_QLEN (dev))
1183 			netif_stop_queue (net);
1184 	}
1185 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1186 
1187 	if (retval) {
1188 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1189 drop:
1190 		dev->net->stats.tx_dropped++;
1191 not_drop:
1192 		if (skb)
1193 			dev_kfree_skb_any (skb);
1194 		usb_free_urb (urb);
1195 	} else
1196 		netif_dbg(dev, tx_queued, dev->net,
1197 			  "> tx, len %d, type 0x%x\n", length, skb->protocol);
1198 #ifdef CONFIG_PM
1199 deferred:
1200 #endif
1201 	return NETDEV_TX_OK;
1202 }
1203 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1204 
1205 /*-------------------------------------------------------------------------*/
1206 
1207 // tasklet (work deferred from completions, in_irq) or timer
1208 
usbnet_bh(unsigned long param)1209 static void usbnet_bh (unsigned long param)
1210 {
1211 	struct usbnet		*dev = (struct usbnet *) param;
1212 	struct sk_buff		*skb;
1213 	struct skb_data		*entry;
1214 
1215 	while ((skb = skb_dequeue (&dev->done))) {
1216 		entry = (struct skb_data *) skb->cb;
1217 		switch (entry->state) {
1218 		case rx_done:
1219 			entry->state = rx_cleanup;
1220 			rx_process (dev, skb);
1221 			continue;
1222 		case tx_done:
1223 		case rx_cleanup:
1224 			usb_free_urb (entry->urb);
1225 			dev_kfree_skb (skb);
1226 			continue;
1227 		default:
1228 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1229 		}
1230 	}
1231 
1232 	// waiting for all pending urbs to complete?
1233 	if (dev->wait) {
1234 		if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
1235 			wake_up (dev->wait);
1236 		}
1237 
1238 	// or are we maybe short a few urbs?
1239 	} else if (netif_running (dev->net) &&
1240 		   netif_device_present (dev->net) &&
1241 		   !timer_pending (&dev->delay) &&
1242 		   !test_bit (EVENT_RX_HALT, &dev->flags)) {
1243 		int	temp = dev->rxq.qlen;
1244 		int	qlen = RX_QLEN (dev);
1245 
1246 		if (temp < qlen) {
1247 			struct urb	*urb;
1248 			int		i;
1249 
1250 			// don't refill the queue all at once
1251 			for (i = 0; i < 10 && dev->rxq.qlen < qlen; i++) {
1252 				urb = usb_alloc_urb (0, GFP_ATOMIC);
1253 				if (urb != NULL) {
1254 					if (rx_submit (dev, urb, GFP_ATOMIC) ==
1255 					    -ENOLINK)
1256 						return;
1257 				}
1258 			}
1259 			if (temp != dev->rxq.qlen)
1260 				netif_dbg(dev, link, dev->net,
1261 					  "rxqlen %d --> %d\n",
1262 					  temp, dev->rxq.qlen);
1263 			if (dev->rxq.qlen < qlen)
1264 				tasklet_schedule (&dev->bh);
1265 		}
1266 		if (dev->txq.qlen < TX_QLEN (dev))
1267 			netif_wake_queue (dev->net);
1268 	}
1269 }
1270 
1271 
1272 /*-------------------------------------------------------------------------
1273  *
1274  * USB Device Driver support
1275  *
1276  *-------------------------------------------------------------------------*/
1277 
1278 // precondition: never called in_interrupt
1279 
usbnet_disconnect(struct usb_interface * intf)1280 void usbnet_disconnect (struct usb_interface *intf)
1281 {
1282 	struct usbnet		*dev;
1283 	struct usb_device	*xdev;
1284 	struct net_device	*net;
1285 
1286 	dev = usb_get_intfdata(intf);
1287 	usb_set_intfdata(intf, NULL);
1288 	if (!dev)
1289 		return;
1290 
1291 	xdev = interface_to_usbdev (intf);
1292 
1293 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1294 		   intf->dev.driver->name,
1295 		   xdev->bus->bus_name, xdev->devpath,
1296 		   dev->driver_info->description);
1297 
1298 	net = dev->net;
1299 	unregister_netdev (net);
1300 
1301 	cancel_work_sync(&dev->kevent);
1302 
1303 	usb_scuttle_anchored_urbs(&dev->deferred);
1304 
1305 	if (dev->driver_info->unbind)
1306 		dev->driver_info->unbind (dev, intf);
1307 
1308 	usb_kill_urb(dev->interrupt);
1309 	usb_free_urb(dev->interrupt);
1310 
1311 	free_netdev(net);
1312 	usb_put_dev (xdev);
1313 }
1314 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1315 
1316 static const struct net_device_ops usbnet_netdev_ops = {
1317 	.ndo_open		= usbnet_open,
1318 	.ndo_stop		= usbnet_stop,
1319 	.ndo_start_xmit		= usbnet_start_xmit,
1320 	.ndo_tx_timeout		= usbnet_tx_timeout,
1321 	.ndo_change_mtu		= usbnet_change_mtu,
1322 	.ndo_set_mac_address 	= eth_mac_addr,
1323 	.ndo_validate_addr	= eth_validate_addr,
1324 };
1325 
1326 /*-------------------------------------------------------------------------*/
1327 
1328 // precondition: never called in_interrupt
1329 
1330 static struct device_type wlan_type = {
1331 	.name	= "wlan",
1332 };
1333 
1334 static struct device_type wwan_type = {
1335 	.name	= "wwan",
1336 };
1337 
1338 int
usbnet_probe(struct usb_interface * udev,const struct usb_device_id * prod)1339 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1340 {
1341 	struct usbnet			*dev;
1342 	struct net_device		*net;
1343 	struct usb_host_interface	*interface;
1344 	struct driver_info		*info;
1345 	struct usb_device		*xdev;
1346 	int				status;
1347 	const char			*name;
1348 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1349 
1350 	/* usbnet already took usb runtime pm, so have to enable the feature
1351 	 * for usb interface, otherwise usb_autopm_get_interface may return
1352 	 * failure if USB_SUSPEND(RUNTIME_PM) is enabled.
1353 	 */
1354 	if (!driver->supports_autosuspend) {
1355 		driver->supports_autosuspend = 1;
1356 		pm_runtime_enable(&udev->dev);
1357 	}
1358 
1359 	name = udev->dev.driver->name;
1360 	info = (struct driver_info *) prod->driver_info;
1361 	if (!info) {
1362 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1363 		return -ENODEV;
1364 	}
1365 	xdev = interface_to_usbdev (udev);
1366 	interface = udev->cur_altsetting;
1367 
1368 	usb_get_dev (xdev);
1369 
1370 	status = -ENOMEM;
1371 
1372 	// set up our own records
1373 	net = alloc_etherdev(sizeof(*dev));
1374 	if (!net)
1375 		goto out;
1376 
1377 	/* netdev_printk() needs this so do it as early as possible */
1378 	SET_NETDEV_DEV(net, &udev->dev);
1379 
1380 	dev = netdev_priv(net);
1381 	dev->udev = xdev;
1382 	dev->intf = udev;
1383 	dev->driver_info = info;
1384 	dev->driver_name = name;
1385 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1386 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1387 	skb_queue_head_init (&dev->rxq);
1388 	skb_queue_head_init (&dev->txq);
1389 	skb_queue_head_init (&dev->done);
1390 	skb_queue_head_init(&dev->rxq_pause);
1391 	dev->bh.func = usbnet_bh;
1392 	dev->bh.data = (unsigned long) dev;
1393 	INIT_WORK (&dev->kevent, kevent);
1394 	init_usb_anchor(&dev->deferred);
1395 	dev->delay.function = usbnet_bh;
1396 	dev->delay.data = (unsigned long) dev;
1397 	init_timer (&dev->delay);
1398 	mutex_init (&dev->phy_mutex);
1399 
1400 	dev->net = net;
1401 	strcpy (net->name, "usb%d");
1402 	memcpy (net->dev_addr, node_id, sizeof node_id);
1403 
1404 	/* rx and tx sides can use different message sizes;
1405 	 * bind() should set rx_urb_size in that case.
1406 	 */
1407 	dev->hard_mtu = net->mtu + net->hard_header_len;
1408 #if 0
1409 // dma_supported() is deeply broken on almost all architectures
1410 	// possible with some EHCI controllers
1411 	if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1412 		net->features |= NETIF_F_HIGHDMA;
1413 #endif
1414 
1415 	net->netdev_ops = &usbnet_netdev_ops;
1416 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1417 	net->ethtool_ops = &usbnet_ethtool_ops;
1418 
1419 	// allow device-specific bind/init procedures
1420 	// NOTE net->name still not usable ...
1421 	if (info->bind) {
1422 		status = info->bind (dev, udev);
1423 		if (status < 0)
1424 			goto out1;
1425 
1426 		// heuristic:  "usb%d" for links we know are two-host,
1427 		// else "eth%d" when there's reasonable doubt.  userspace
1428 		// can rename the link if it knows better.
1429 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1430 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1431 		     (net->dev_addr [0] & 0x02) == 0))
1432 			strcpy (net->name, "eth%d");
1433 		/* WLAN devices should always be named "wlan%d" */
1434 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1435 			strcpy(net->name, "wlan%d");
1436 		/* WWAN devices should always be named "wwan%d" */
1437 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1438 			strcpy(net->name, "wwan%d");
1439 
1440 		/* maybe the remote can't receive an Ethernet MTU */
1441 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1442 			net->mtu = dev->hard_mtu - net->hard_header_len;
1443 	} else if (!info->in || !info->out)
1444 		status = usbnet_get_endpoints (dev, udev);
1445 	else {
1446 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1447 		dev->out = usb_sndbulkpipe (xdev, info->out);
1448 		if (!(info->flags & FLAG_NO_SETINT))
1449 			status = usb_set_interface (xdev,
1450 				interface->desc.bInterfaceNumber,
1451 				interface->desc.bAlternateSetting);
1452 		else
1453 			status = 0;
1454 
1455 	}
1456 	if (status >= 0 && dev->status)
1457 		status = init_status (dev, udev);
1458 	if (status < 0)
1459 		goto out3;
1460 
1461 	if (!dev->rx_urb_size)
1462 		dev->rx_urb_size = dev->hard_mtu;
1463 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1464 
1465 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1466 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1467 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1468 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1469 
1470 	status = register_netdev (net);
1471 	if (status)
1472 		goto out4;
1473 	netif_info(dev, probe, dev->net,
1474 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1475 		   udev->dev.driver->name,
1476 		   xdev->bus->bus_name, xdev->devpath,
1477 		   dev->driver_info->description,
1478 		   net->dev_addr);
1479 
1480 	// ok, it's ready to go.
1481 	usb_set_intfdata (udev, dev);
1482 
1483 	netif_device_attach (net);
1484 
1485 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1486 		netif_carrier_off(net);
1487 
1488 	return 0;
1489 
1490 out4:
1491 	usb_free_urb(dev->interrupt);
1492 out3:
1493 	if (info->unbind)
1494 		info->unbind (dev, udev);
1495 out1:
1496 	free_netdev(net);
1497 out:
1498 	usb_put_dev(xdev);
1499 	return status;
1500 }
1501 EXPORT_SYMBOL_GPL(usbnet_probe);
1502 
1503 /*-------------------------------------------------------------------------*/
1504 
1505 /*
1506  * suspend the whole driver as soon as the first interface is suspended
1507  * resume only when the last interface is resumed
1508  */
1509 
usbnet_suspend(struct usb_interface * intf,pm_message_t message)1510 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1511 {
1512 	struct usbnet		*dev = usb_get_intfdata(intf);
1513 
1514 	if (!dev->suspend_count++) {
1515 		spin_lock_irq(&dev->txq.lock);
1516 		/* don't autosuspend while transmitting */
1517 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1518 			spin_unlock_irq(&dev->txq.lock);
1519 			return -EBUSY;
1520 		} else {
1521 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1522 			spin_unlock_irq(&dev->txq.lock);
1523 		}
1524 		/*
1525 		 * accelerate emptying of the rx and queues, to avoid
1526 		 * having everything error out.
1527 		 */
1528 		netif_device_detach (dev->net);
1529 		usbnet_terminate_urbs(dev);
1530 		usb_kill_urb(dev->interrupt);
1531 
1532 		/*
1533 		 * reattach so runtime management can use and
1534 		 * wake the device
1535 		 */
1536 		netif_device_attach (dev->net);
1537 	}
1538 	return 0;
1539 }
1540 EXPORT_SYMBOL_GPL(usbnet_suspend);
1541 
usbnet_resume(struct usb_interface * intf)1542 int usbnet_resume (struct usb_interface *intf)
1543 {
1544 	struct usbnet		*dev = usb_get_intfdata(intf);
1545 	struct sk_buff          *skb;
1546 	struct urb              *res;
1547 	int                     retval;
1548 
1549 	if (!--dev->suspend_count) {
1550 		/* resume interrupt URBs */
1551 		if (dev->interrupt && test_bit(EVENT_DEV_OPEN, &dev->flags))
1552 			usb_submit_urb(dev->interrupt, GFP_NOIO);
1553 
1554 		spin_lock_irq(&dev->txq.lock);
1555 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1556 
1557 			skb = (struct sk_buff *)res->context;
1558 			retval = usb_submit_urb(res, GFP_ATOMIC);
1559 			if (retval < 0) {
1560 				dev_kfree_skb_any(skb);
1561 				usb_free_urb(res);
1562 				usb_autopm_put_interface_async(dev->intf);
1563 			} else {
1564 				dev->net->trans_start = jiffies;
1565 				__skb_queue_tail(&dev->txq, skb);
1566 			}
1567 		}
1568 
1569 		smp_mb();
1570 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1571 		spin_unlock_irq(&dev->txq.lock);
1572 
1573 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1574 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1575 				netif_tx_wake_all_queues(dev->net);
1576 			tasklet_schedule (&dev->bh);
1577 		}
1578 	}
1579 	return 0;
1580 }
1581 EXPORT_SYMBOL_GPL(usbnet_resume);
1582 
1583 
1584 /*-------------------------------------------------------------------------*/
1585 
usbnet_init(void)1586 static int __init usbnet_init(void)
1587 {
1588 	/* Compiler should optimize this out. */
1589 	BUILD_BUG_ON(
1590 		FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
1591 
1592 	random_ether_addr(node_id);
1593 	return 0;
1594 }
1595 module_init(usbnet_init);
1596 
usbnet_exit(void)1597 static void __exit usbnet_exit(void)
1598 {
1599 }
1600 module_exit(usbnet_exit);
1601 
1602 MODULE_AUTHOR("David Brownell");
1603 MODULE_DESCRIPTION("USB network driver framework");
1604 MODULE_LICENSE("GPL");
1605