xref: /linux/drivers/net/usb/usbnet.c (revision 0da908c291070d89482f6211dbe81d4d43c3f7cb)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * USB Network driver infrastructure
4  * Copyright (C) 2000-2005 by David Brownell
5  * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.com>
6  */
7 
8 /*
9  * This is a generic "USB networking" framework that works with several
10  * kinds of full and high speed networking devices:  host-to-host cables,
11  * smart usb peripherals, and actual Ethernet adapters.
12  *
13  * These devices usually differ in terms of control protocols (if they
14  * even have one!) and sometimes they define new framing to wrap or batch
15  * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
16  * so interface (un)binding, endpoint I/O queues, fault handling, and other
17  * issues can usefully be addressed by this framework.
18  */
19 
20 #include <linux/module.h>
21 #include <linux/init.h>
22 #include <linux/netdevice.h>
23 #include <linux/etherdevice.h>
24 #include <linux/ctype.h>
25 #include <linux/ethtool.h>
26 #include <linux/workqueue.h>
27 #include <linux/mii.h>
28 #include <linux/usb.h>
29 #include <linux/usb/usbnet.h>
30 #include <linux/slab.h>
31 #include <linux/kernel.h>
32 #include <linux/pm_runtime.h>
33 
34 /*-------------------------------------------------------------------------*/
35 
36 /*
37  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
38  * Several dozen bytes of IPv4 data can fit in two such transactions.
39  * One maximum size Ethernet packet takes twenty four of them.
40  * For high speed, each frame comfortably fits almost 36 max size
41  * Ethernet packets (so queues should be bigger).
42  *
43  * The goal is to let the USB host controller be busy for 5msec or
44  * more before an irq is required, under load.  Jumbograms change
45  * the equation.
46  */
47 #define	MAX_QUEUE_MEMORY	(60 * 1518)
48 #define	RX_QLEN(dev)		((dev)->rx_qlen)
49 #define	TX_QLEN(dev)		((dev)->tx_qlen)
50 
51 // reawaken network queue this soon after stopping; else watchdog barks
52 #define TX_TIMEOUT_JIFFIES	(5*HZ)
53 
54 /* throttle rx/tx briefly after some faults, so hub_wq might disconnect()
55  * us (it polls at HZ/4 usually) before we report too many false errors.
56  */
57 #define THROTTLE_JIFFIES	(HZ/8)
58 
59 // between wakeups
60 #define UNLINK_TIMEOUT_MS	3
61 
62 /*-------------------------------------------------------------------------*/
63 
64 // randomly generated ethernet address
65 static u8	node_id [ETH_ALEN];
66 
67 /* use ethtool to change the level for any given device */
68 static int msg_level = -1;
69 module_param (msg_level, int, 0);
70 MODULE_PARM_DESC (msg_level, "Override default message level");
71 
72 /*-------------------------------------------------------------------------*/
73 
74 static const char * const usbnet_event_names[] = {
75 	[EVENT_TX_HALT]		   = "EVENT_TX_HALT",
76 	[EVENT_RX_HALT]		   = "EVENT_RX_HALT",
77 	[EVENT_RX_MEMORY]	   = "EVENT_RX_MEMORY",
78 	[EVENT_STS_SPLIT]	   = "EVENT_STS_SPLIT",
79 	[EVENT_LINK_RESET]	   = "EVENT_LINK_RESET",
80 	[EVENT_RX_PAUSED]	   = "EVENT_RX_PAUSED",
81 	[EVENT_DEV_ASLEEP]	   = "EVENT_DEV_ASLEEP",
82 	[EVENT_DEV_OPEN]	   = "EVENT_DEV_OPEN",
83 	[EVENT_DEVICE_REPORT_IDLE] = "EVENT_DEVICE_REPORT_IDLE",
84 	[EVENT_NO_RUNTIME_PM]	   = "EVENT_NO_RUNTIME_PM",
85 	[EVENT_RX_KILL]		   = "EVENT_RX_KILL",
86 	[EVENT_LINK_CHANGE]	   = "EVENT_LINK_CHANGE",
87 	[EVENT_SET_RX_MODE]	   = "EVENT_SET_RX_MODE",
88 	[EVENT_NO_IP_ALIGN]	   = "EVENT_NO_IP_ALIGN",
89 };
90 
91 /* handles CDC Ethernet and many other network "bulk data" interfaces */
92 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
93 {
94 	int				tmp;
95 	struct usb_host_interface	*alt = NULL;
96 	struct usb_host_endpoint	*in = NULL, *out = NULL;
97 	struct usb_host_endpoint	*status = NULL;
98 
99 	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
100 		unsigned	ep;
101 
102 		in = out = status = NULL;
103 		alt = intf->altsetting + tmp;
104 
105 		/* take the first altsetting with in-bulk + out-bulk;
106 		 * remember any status endpoint, just in case;
107 		 * ignore other endpoints and altsettings.
108 		 */
109 		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
110 			struct usb_host_endpoint	*e;
111 			int				intr = 0;
112 
113 			e = alt->endpoint + ep;
114 
115 			/* ignore endpoints which cannot transfer data */
116 			if (!usb_endpoint_maxp(&e->desc))
117 				continue;
118 
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 	u8		addr[ETH_ALEN];
166 	int 		tmp = -1, ret;
167 	unsigned char	buf [13];
168 
169 	ret = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
170 	if (ret == 12)
171 		tmp = hex2bin(addr, buf, 6);
172 	if (tmp < 0) {
173 		dev_dbg(&dev->udev->dev,
174 			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
175 		if (ret >= 0)
176 			ret = -EINVAL;
177 		return ret;
178 	}
179 	eth_hw_addr_set(dev->net, addr);
180 	return 0;
181 }
182 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
183 
184 static void intr_complete (struct urb *urb)
185 {
186 	struct usbnet	*dev = urb->context;
187 	int		status = urb->status;
188 
189 	switch (status) {
190 	/* success */
191 	case 0:
192 		dev->driver_info->status(dev, urb);
193 		break;
194 
195 	/* software-driven interface shutdown */
196 	case -ENOENT:		/* urb killed */
197 	case -ESHUTDOWN:	/* hardware gone */
198 		netif_dbg(dev, ifdown, dev->net,
199 			  "intr shutdown, code %d\n", status);
200 		return;
201 
202 	/* NOTE:  not throttling like RX/TX, since this endpoint
203 	 * already polls infrequently
204 	 */
205 	default:
206 		netdev_dbg(dev->net, "intr status %d\n", status);
207 		break;
208 	}
209 
210 	status = usb_submit_urb (urb, GFP_ATOMIC);
211 	if (status != 0)
212 		netif_err(dev, timer, dev->net,
213 			  "intr resubmit --> %d\n", status);
214 }
215 
216 static int init_status (struct usbnet *dev, struct usb_interface *intf)
217 {
218 	char		*buf = NULL;
219 	unsigned	pipe = 0;
220 	unsigned	maxp;
221 	unsigned	period;
222 
223 	if (!dev->driver_info->status)
224 		return 0;
225 
226 	pipe = usb_rcvintpipe (dev->udev,
227 			dev->status->desc.bEndpointAddress
228 				& USB_ENDPOINT_NUMBER_MASK);
229 	maxp = usb_maxpacket(dev->udev, pipe);
230 
231 	/* avoid 1 msec chatter:  min 8 msec poll rate */
232 	period = max ((int) dev->status->desc.bInterval,
233 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
234 
235 	buf = kmalloc (maxp, GFP_KERNEL);
236 	if (buf) {
237 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
238 		if (!dev->interrupt) {
239 			kfree (buf);
240 			return -ENOMEM;
241 		} else {
242 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
243 				buf, maxp, intr_complete, dev, period);
244 			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
245 			dev_dbg(&intf->dev,
246 				"status ep%din, %d bytes period %d\n",
247 				usb_pipeendpoint(pipe), maxp, period);
248 		}
249 	}
250 	return 0;
251 }
252 
253 /* Submit the interrupt URB if not previously submitted, increasing refcount */
254 int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
255 {
256 	int ret = 0;
257 
258 	WARN_ON_ONCE(dev->interrupt == NULL);
259 	if (dev->interrupt) {
260 		mutex_lock(&dev->interrupt_mutex);
261 
262 		if (++dev->interrupt_count == 1)
263 			ret = usb_submit_urb(dev->interrupt, mem_flags);
264 
265 		dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
266 			dev->interrupt_count);
267 		mutex_unlock(&dev->interrupt_mutex);
268 	}
269 	return ret;
270 }
271 EXPORT_SYMBOL_GPL(usbnet_status_start);
272 
273 /* For resume; submit interrupt URB if previously submitted */
274 static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
275 {
276 	int ret = 0;
277 
278 	mutex_lock(&dev->interrupt_mutex);
279 	if (dev->interrupt_count) {
280 		ret = usb_submit_urb(dev->interrupt, mem_flags);
281 		dev_dbg(&dev->udev->dev,
282 			"submitted interrupt URB for resume\n");
283 	}
284 	mutex_unlock(&dev->interrupt_mutex);
285 	return ret;
286 }
287 
288 /* Kill the interrupt URB if all submitters want it killed */
289 void usbnet_status_stop(struct usbnet *dev)
290 {
291 	if (dev->interrupt) {
292 		mutex_lock(&dev->interrupt_mutex);
293 		WARN_ON(dev->interrupt_count == 0);
294 
295 		if (dev->interrupt_count && --dev->interrupt_count == 0)
296 			usb_kill_urb(dev->interrupt);
297 
298 		dev_dbg(&dev->udev->dev,
299 			"decremented interrupt URB count to %d\n",
300 			dev->interrupt_count);
301 		mutex_unlock(&dev->interrupt_mutex);
302 	}
303 }
304 EXPORT_SYMBOL_GPL(usbnet_status_stop);
305 
306 /* For suspend; always kill interrupt URB */
307 static void __usbnet_status_stop_force(struct usbnet *dev)
308 {
309 	if (dev->interrupt) {
310 		mutex_lock(&dev->interrupt_mutex);
311 		usb_kill_urb(dev->interrupt);
312 		dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
313 		mutex_unlock(&dev->interrupt_mutex);
314 	}
315 }
316 
317 /* Passes this packet up the stack, updating its accounting.
318  * Some link protocols batch packets, so their rx_fixup paths
319  * can return clones as well as just modify the original skb.
320  */
321 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
322 {
323 	struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->net->tstats);
324 	unsigned long flags;
325 	int	status;
326 
327 	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
328 		skb_queue_tail(&dev->rxq_pause, skb);
329 		return;
330 	}
331 
332 	/* only update if unset to allow minidriver rx_fixup override */
333 	if (skb->protocol == 0)
334 		skb->protocol = eth_type_trans (skb, dev->net);
335 
336 	flags = u64_stats_update_begin_irqsave(&stats64->syncp);
337 	u64_stats_inc(&stats64->rx_packets);
338 	u64_stats_add(&stats64->rx_bytes, skb->len);
339 	u64_stats_update_end_irqrestore(&stats64->syncp, flags);
340 
341 	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
342 		  skb->len + sizeof (struct ethhdr), skb->protocol);
343 	memset (skb->cb, 0, sizeof (struct skb_data));
344 
345 	if (skb_defer_rx_timestamp(skb))
346 		return;
347 
348 	status = netif_rx (skb);
349 	if (status != NET_RX_SUCCESS)
350 		netif_dbg(dev, rx_err, dev->net,
351 			  "netif_rx status %d\n", status);
352 }
353 EXPORT_SYMBOL_GPL(usbnet_skb_return);
354 
355 /* must be called if hard_mtu or rx_urb_size changed */
356 void usbnet_update_max_qlen(struct usbnet *dev)
357 {
358 	enum usb_device_speed speed = dev->udev->speed;
359 
360 	if (!dev->rx_urb_size || !dev->hard_mtu)
361 		goto insanity;
362 	switch (speed) {
363 	case USB_SPEED_HIGH:
364 		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
365 		dev->tx_qlen = MAX_QUEUE_MEMORY / dev->hard_mtu;
366 		break;
367 	case USB_SPEED_SUPER:
368 	case USB_SPEED_SUPER_PLUS:
369 		/*
370 		 * Not take default 5ms qlen for super speed HC to
371 		 * save memory, and iperf tests show 2.5ms qlen can
372 		 * work well
373 		 */
374 		dev->rx_qlen = 5 * MAX_QUEUE_MEMORY / dev->rx_urb_size;
375 		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
376 		break;
377 	default:
378 insanity:
379 		dev->rx_qlen = dev->tx_qlen = 4;
380 	}
381 }
382 EXPORT_SYMBOL_GPL(usbnet_update_max_qlen);
383 
384 
385 /*-------------------------------------------------------------------------
386  *
387  * Network Device Driver (peer link to "Host Device", from USB host)
388  *
389  *-------------------------------------------------------------------------*/
390 
391 int usbnet_change_mtu (struct net_device *net, int new_mtu)
392 {
393 	struct usbnet	*dev = netdev_priv(net);
394 	int		ll_mtu = new_mtu + net->hard_header_len;
395 	int		old_hard_mtu = dev->hard_mtu;
396 	int		old_rx_urb_size = dev->rx_urb_size;
397 
398 	// no second zero-length packet read wanted after mtu-sized packets
399 	if ((ll_mtu % dev->maxpacket) == 0)
400 		return -EDOM;
401 	net->mtu = new_mtu;
402 
403 	dev->hard_mtu = net->mtu + net->hard_header_len;
404 	if (dev->rx_urb_size == old_hard_mtu) {
405 		dev->rx_urb_size = dev->hard_mtu;
406 		if (dev->rx_urb_size > old_rx_urb_size) {
407 			usbnet_pause_rx(dev);
408 			usbnet_unlink_rx_urbs(dev);
409 			usbnet_resume_rx(dev);
410 		}
411 	}
412 
413 	/* max qlen depend on hard_mtu and rx_urb_size */
414 	usbnet_update_max_qlen(dev);
415 
416 	return 0;
417 }
418 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
419 
420 /* The caller must hold list->lock */
421 static void __usbnet_queue_skb(struct sk_buff_head *list,
422 			struct sk_buff *newsk, enum skb_state state)
423 {
424 	struct skb_data *entry = (struct skb_data *) newsk->cb;
425 
426 	__skb_queue_tail(list, newsk);
427 	entry->state = state;
428 }
429 
430 /*-------------------------------------------------------------------------*/
431 
432 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
433  * completion callbacks.  2.5 should have fixed those bugs...
434  */
435 
436 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
437 		struct sk_buff_head *list, enum skb_state state)
438 {
439 	unsigned long		flags;
440 	enum skb_state 		old_state;
441 	struct skb_data *entry = (struct skb_data *) skb->cb;
442 
443 	spin_lock_irqsave(&list->lock, flags);
444 	old_state = entry->state;
445 	entry->state = state;
446 	__skb_unlink(skb, list);
447 
448 	/* defer_bh() is never called with list == &dev->done.
449 	 * spin_lock_nested() tells lockdep that it is OK to take
450 	 * dev->done.lock here with list->lock held.
451 	 */
452 	spin_lock_nested(&dev->done.lock, SINGLE_DEPTH_NESTING);
453 
454 	__skb_queue_tail(&dev->done, skb);
455 	if (dev->done.qlen == 1)
456 		tasklet_schedule(&dev->bh);
457 	spin_unlock(&dev->done.lock);
458 	spin_unlock_irqrestore(&list->lock, flags);
459 	return old_state;
460 }
461 
462 /* some work can't be done in tasklets, so we use keventd
463  *
464  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
465  * but tasklet_schedule() doesn't.  hope the failure is rare.
466  */
467 void usbnet_defer_kevent (struct usbnet *dev, int work)
468 {
469 	set_bit (work, &dev->flags);
470 	if (!schedule_work (&dev->kevent))
471 		netdev_dbg(dev->net, "kevent %s may have been dropped\n", usbnet_event_names[work]);
472 	else
473 		netdev_dbg(dev->net, "kevent %s scheduled\n", usbnet_event_names[work]);
474 }
475 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
476 
477 /*-------------------------------------------------------------------------*/
478 
479 static void rx_complete (struct urb *urb);
480 
481 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
482 {
483 	struct sk_buff		*skb;
484 	struct skb_data		*entry;
485 	int			retval = 0;
486 	unsigned long		lockflags;
487 	size_t			size = dev->rx_urb_size;
488 
489 	/* prevent rx skb allocation when error ratio is high */
490 	if (test_bit(EVENT_RX_KILL, &dev->flags)) {
491 		usb_free_urb(urb);
492 		return -ENOLINK;
493 	}
494 
495 	if (test_bit(EVENT_NO_IP_ALIGN, &dev->flags))
496 		skb = __netdev_alloc_skb(dev->net, size, flags);
497 	else
498 		skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
499 	if (!skb) {
500 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
501 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
502 		usb_free_urb (urb);
503 		return -ENOMEM;
504 	}
505 
506 	entry = (struct skb_data *) skb->cb;
507 	entry->urb = urb;
508 	entry->dev = dev;
509 	entry->length = 0;
510 
511 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
512 		skb->data, size, rx_complete, skb);
513 
514 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
515 
516 	if (netif_running (dev->net) &&
517 	    netif_device_present (dev->net) &&
518 	    test_bit(EVENT_DEV_OPEN, &dev->flags) &&
519 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
520 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
521 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
522 		case -EPIPE:
523 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
524 			break;
525 		case -ENOMEM:
526 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
527 			break;
528 		case -ENODEV:
529 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
530 			netif_device_detach (dev->net);
531 			break;
532 		case -EHOSTUNREACH:
533 			retval = -ENOLINK;
534 			break;
535 		default:
536 			netif_dbg(dev, rx_err, dev->net,
537 				  "rx submit, %d\n", retval);
538 			tasklet_schedule (&dev->bh);
539 			break;
540 		case 0:
541 			__usbnet_queue_skb(&dev->rxq, skb, rx_start);
542 		}
543 	} else {
544 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
545 		retval = -ENOLINK;
546 	}
547 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
548 	if (retval) {
549 		dev_kfree_skb_any (skb);
550 		usb_free_urb (urb);
551 	}
552 	return retval;
553 }
554 
555 
556 /*-------------------------------------------------------------------------*/
557 
558 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
559 {
560 	if (dev->driver_info->rx_fixup &&
561 	    !dev->driver_info->rx_fixup (dev, skb)) {
562 		/* With RX_ASSEMBLE, rx_fixup() must update counters */
563 		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
564 			dev->net->stats.rx_errors++;
565 		goto done;
566 	}
567 	// else network stack removes extra byte if we forced a short packet
568 
569 	/* all data was already cloned from skb inside the driver */
570 	if (dev->driver_info->flags & FLAG_MULTI_PACKET)
571 		goto done;
572 
573 	if (skb->len < ETH_HLEN) {
574 		dev->net->stats.rx_errors++;
575 		dev->net->stats.rx_length_errors++;
576 		netif_dbg(dev, rx_err, dev->net, "rx length %d\n", skb->len);
577 	} else {
578 		usbnet_skb_return(dev, skb);
579 		return;
580 	}
581 
582 done:
583 	skb_queue_tail(&dev->done, skb);
584 }
585 
586 /*-------------------------------------------------------------------------*/
587 
588 static void rx_complete (struct urb *urb)
589 {
590 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
591 	struct skb_data		*entry = (struct skb_data *) skb->cb;
592 	struct usbnet		*dev = entry->dev;
593 	int			urb_status = urb->status;
594 	enum skb_state		state;
595 
596 	skb_put (skb, urb->actual_length);
597 	state = rx_done;
598 	entry->urb = NULL;
599 
600 	switch (urb_status) {
601 	/* success */
602 	case 0:
603 		break;
604 
605 	/* stalls need manual reset. this is rare ... except that
606 	 * when going through USB 2.0 TTs, unplug appears this way.
607 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
608 	 * storm, recovering as needed.
609 	 */
610 	case -EPIPE:
611 		dev->net->stats.rx_errors++;
612 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
613 		fallthrough;
614 
615 	/* software-driven interface shutdown */
616 	case -ECONNRESET:		/* async unlink */
617 	case -ESHUTDOWN:		/* hardware gone */
618 		netif_dbg(dev, ifdown, dev->net,
619 			  "rx shutdown, code %d\n", urb_status);
620 		goto block;
621 
622 	/* we get controller i/o faults during hub_wq disconnect() delays.
623 	 * throttle down resubmits, to avoid log floods; just temporarily,
624 	 * so we still recover when the fault isn't a hub_wq delay.
625 	 */
626 	case -EPROTO:
627 	case -ETIME:
628 	case -EILSEQ:
629 		dev->net->stats.rx_errors++;
630 		if (!timer_pending (&dev->delay)) {
631 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
632 			netif_dbg(dev, link, dev->net,
633 				  "rx throttle %d\n", urb_status);
634 		}
635 block:
636 		state = rx_cleanup;
637 		entry->urb = urb;
638 		urb = NULL;
639 		break;
640 
641 	/* data overrun ... flush fifo? */
642 	case -EOVERFLOW:
643 		dev->net->stats.rx_over_errors++;
644 		fallthrough;
645 
646 	default:
647 		state = rx_cleanup;
648 		dev->net->stats.rx_errors++;
649 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
650 		break;
651 	}
652 
653 	/* stop rx if packet error rate is high */
654 	if (++dev->pkt_cnt > 30) {
655 		dev->pkt_cnt = 0;
656 		dev->pkt_err = 0;
657 	} else {
658 		if (state == rx_cleanup)
659 			dev->pkt_err++;
660 		if (dev->pkt_err > 20)
661 			set_bit(EVENT_RX_KILL, &dev->flags);
662 	}
663 
664 	state = defer_bh(dev, skb, &dev->rxq, state);
665 
666 	if (urb) {
667 		if (netif_running (dev->net) &&
668 		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
669 		    state != unlink_start) {
670 			rx_submit (dev, urb, GFP_ATOMIC);
671 			usb_mark_last_busy(dev->udev);
672 			return;
673 		}
674 		usb_free_urb (urb);
675 	}
676 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
677 }
678 
679 /*-------------------------------------------------------------------------*/
680 void usbnet_pause_rx(struct usbnet *dev)
681 {
682 	set_bit(EVENT_RX_PAUSED, &dev->flags);
683 
684 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
685 }
686 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
687 
688 void usbnet_resume_rx(struct usbnet *dev)
689 {
690 	struct sk_buff *skb;
691 	int num = 0;
692 
693 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
694 
695 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
696 		usbnet_skb_return(dev, skb);
697 		num++;
698 	}
699 
700 	tasklet_schedule(&dev->bh);
701 
702 	netif_dbg(dev, rx_status, dev->net,
703 		  "paused rx queue disabled, %d skbs requeued\n", num);
704 }
705 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
706 
707 void usbnet_purge_paused_rxq(struct usbnet *dev)
708 {
709 	skb_queue_purge(&dev->rxq_pause);
710 }
711 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
712 
713 /*-------------------------------------------------------------------------*/
714 
715 // unlink pending rx/tx; completion handlers do all other cleanup
716 
717 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
718 {
719 	unsigned long		flags;
720 	struct sk_buff		*skb;
721 	int			count = 0;
722 
723 	spin_lock_irqsave (&q->lock, flags);
724 	while (!skb_queue_empty(q)) {
725 		struct skb_data		*entry;
726 		struct urb		*urb;
727 		int			retval;
728 
729 		skb_queue_walk(q, skb) {
730 			entry = (struct skb_data *) skb->cb;
731 			if (entry->state != unlink_start)
732 				goto found;
733 		}
734 		break;
735 found:
736 		entry->state = unlink_start;
737 		urb = entry->urb;
738 
739 		/*
740 		 * Get reference count of the URB to avoid it to be
741 		 * freed during usb_unlink_urb, which may trigger
742 		 * use-after-free problem inside usb_unlink_urb since
743 		 * usb_unlink_urb is always racing with .complete
744 		 * handler(include defer_bh).
745 		 */
746 		usb_get_urb(urb);
747 		spin_unlock_irqrestore(&q->lock, flags);
748 		// during some PM-driven resume scenarios,
749 		// these (async) unlinks complete immediately
750 		retval = usb_unlink_urb (urb);
751 		if (retval != -EINPROGRESS && retval != 0)
752 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
753 		else
754 			count++;
755 		usb_put_urb(urb);
756 		spin_lock_irqsave(&q->lock, flags);
757 	}
758 	spin_unlock_irqrestore (&q->lock, flags);
759 	return count;
760 }
761 
762 // Flush all pending rx urbs
763 // minidrivers may need to do this when the MTU changes
764 
765 void usbnet_unlink_rx_urbs(struct usbnet *dev)
766 {
767 	if (netif_running(dev->net)) {
768 		(void) unlink_urbs (dev, &dev->rxq);
769 		tasklet_schedule(&dev->bh);
770 	}
771 }
772 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
773 
774 /*-------------------------------------------------------------------------*/
775 
776 static void wait_skb_queue_empty(struct sk_buff_head *q)
777 {
778 	unsigned long flags;
779 
780 	spin_lock_irqsave(&q->lock, flags);
781 	while (!skb_queue_empty(q)) {
782 		spin_unlock_irqrestore(&q->lock, flags);
783 		schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
784 		set_current_state(TASK_UNINTERRUPTIBLE);
785 		spin_lock_irqsave(&q->lock, flags);
786 	}
787 	spin_unlock_irqrestore(&q->lock, flags);
788 }
789 
790 // precondition: never called in_interrupt
791 static void usbnet_terminate_urbs(struct usbnet *dev)
792 {
793 	DECLARE_WAITQUEUE(wait, current);
794 	int temp;
795 
796 	/* ensure there are no more active urbs */
797 	add_wait_queue(&dev->wait, &wait);
798 	set_current_state(TASK_UNINTERRUPTIBLE);
799 	temp = unlink_urbs(dev, &dev->txq) +
800 		unlink_urbs(dev, &dev->rxq);
801 
802 	/* maybe wait for deletions to finish. */
803 	wait_skb_queue_empty(&dev->rxq);
804 	wait_skb_queue_empty(&dev->txq);
805 	wait_skb_queue_empty(&dev->done);
806 	netif_dbg(dev, ifdown, dev->net,
807 		  "waited for %d urb completions\n", temp);
808 	set_current_state(TASK_RUNNING);
809 	remove_wait_queue(&dev->wait, &wait);
810 }
811 
812 int usbnet_stop (struct net_device *net)
813 {
814 	struct usbnet		*dev = netdev_priv(net);
815 	const struct driver_info *info = dev->driver_info;
816 	int			retval, pm, mpn;
817 
818 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
819 	netif_stop_queue (net);
820 
821 	netif_info(dev, ifdown, dev->net,
822 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
823 		   net->stats.rx_packets, net->stats.tx_packets,
824 		   net->stats.rx_errors, net->stats.tx_errors);
825 
826 	/* to not race resume */
827 	pm = usb_autopm_get_interface(dev->intf);
828 	/* allow minidriver to stop correctly (wireless devices to turn off
829 	 * radio etc) */
830 	if (info->stop) {
831 		retval = info->stop(dev);
832 		if (retval < 0)
833 			netif_info(dev, ifdown, dev->net,
834 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
835 				   retval,
836 				   dev->udev->bus->bus_name, dev->udev->devpath,
837 				   info->description);
838 	}
839 
840 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
841 		usbnet_terminate_urbs(dev);
842 
843 	usbnet_status_stop(dev);
844 
845 	usbnet_purge_paused_rxq(dev);
846 
847 	mpn = !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
848 
849 	/* deferred work (timer, softirq, task) must also stop */
850 	dev->flags = 0;
851 	del_timer_sync (&dev->delay);
852 	tasklet_kill (&dev->bh);
853 	cancel_work_sync(&dev->kevent);
854 	if (!pm)
855 		usb_autopm_put_interface(dev->intf);
856 
857 	if (info->manage_power && mpn)
858 		info->manage_power(dev, 0);
859 	else
860 		usb_autopm_put_interface(dev->intf);
861 
862 	return 0;
863 }
864 EXPORT_SYMBOL_GPL(usbnet_stop);
865 
866 /*-------------------------------------------------------------------------*/
867 
868 // posts reads, and enables write queuing
869 
870 // precondition: never called in_interrupt
871 
872 int usbnet_open (struct net_device *net)
873 {
874 	struct usbnet		*dev = netdev_priv(net);
875 	int			retval;
876 	const struct driver_info *info = dev->driver_info;
877 
878 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
879 		netif_info(dev, ifup, dev->net,
880 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
881 			   retval,
882 			   dev->udev->bus->bus_name,
883 			   dev->udev->devpath,
884 			   info->description);
885 		goto done_nopm;
886 	}
887 
888 	// put into "known safe" state
889 	if (info->reset && (retval = info->reset (dev)) < 0) {
890 		netif_info(dev, ifup, dev->net,
891 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
892 			   retval,
893 			   dev->udev->bus->bus_name,
894 			   dev->udev->devpath,
895 			   info->description);
896 		goto done;
897 	}
898 
899 	/* hard_mtu or rx_urb_size may change in reset() */
900 	usbnet_update_max_qlen(dev);
901 
902 	// insist peer be connected
903 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
904 		netif_err(dev, ifup, dev->net, "can't open; %d\n", retval);
905 		goto done;
906 	}
907 
908 	/* start any status interrupt transfer */
909 	if (dev->interrupt) {
910 		retval = usbnet_status_start(dev, GFP_KERNEL);
911 		if (retval < 0) {
912 			netif_err(dev, ifup, dev->net,
913 				  "intr submit %d\n", retval);
914 			goto done;
915 		}
916 	}
917 
918 	set_bit(EVENT_DEV_OPEN, &dev->flags);
919 	netif_start_queue (net);
920 	netif_info(dev, ifup, dev->net,
921 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
922 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
923 		   dev->net->mtu,
924 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
925 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
926 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
927 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
928 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
929 		   "simple");
930 
931 	/* reset rx error state */
932 	dev->pkt_cnt = 0;
933 	dev->pkt_err = 0;
934 	clear_bit(EVENT_RX_KILL, &dev->flags);
935 
936 	// delay posting reads until we're fully open
937 	tasklet_schedule (&dev->bh);
938 	if (info->manage_power) {
939 		retval = info->manage_power(dev, 1);
940 		if (retval < 0) {
941 			retval = 0;
942 			set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
943 		} else {
944 			usb_autopm_put_interface(dev->intf);
945 		}
946 	}
947 	return retval;
948 done:
949 	usb_autopm_put_interface(dev->intf);
950 done_nopm:
951 	return retval;
952 }
953 EXPORT_SYMBOL_GPL(usbnet_open);
954 
955 /*-------------------------------------------------------------------------*/
956 
957 /* ethtool methods; minidrivers may need to add some more, but
958  * they'll probably want to use this base set.
959  */
960 
961 /* These methods are written on the assumption that the device
962  * uses MII
963  */
964 int usbnet_get_link_ksettings_mii(struct net_device *net,
965 			      struct ethtool_link_ksettings *cmd)
966 {
967 	struct usbnet *dev = netdev_priv(net);
968 
969 	if (!dev->mii.mdio_read)
970 		return -EOPNOTSUPP;
971 
972 	mii_ethtool_get_link_ksettings(&dev->mii, cmd);
973 
974 	return 0;
975 }
976 EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings_mii);
977 
978 int usbnet_get_link_ksettings_internal(struct net_device *net,
979 					struct ethtool_link_ksettings *cmd)
980 {
981 	struct usbnet *dev = netdev_priv(net);
982 
983 	/* the assumption that speed is equal on tx and rx
984 	 * is deeply engrained into the networking layer.
985 	 * For wireless stuff it is not true.
986 	 * We assume that rx_speed matters more.
987 	 */
988 	if (dev->rx_speed != SPEED_UNSET)
989 		cmd->base.speed = dev->rx_speed / 1000000;
990 	else if (dev->tx_speed != SPEED_UNSET)
991 		cmd->base.speed = dev->tx_speed / 1000000;
992 	else
993 		cmd->base.speed = SPEED_UNKNOWN;
994 
995 	return 0;
996 }
997 EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings_internal);
998 
999 int usbnet_set_link_ksettings_mii(struct net_device *net,
1000 			      const struct ethtool_link_ksettings *cmd)
1001 {
1002 	struct usbnet *dev = netdev_priv(net);
1003 	int retval;
1004 
1005 	if (!dev->mii.mdio_write)
1006 		return -EOPNOTSUPP;
1007 
1008 	retval = mii_ethtool_set_link_ksettings(&dev->mii, cmd);
1009 
1010 	/* link speed/duplex might have changed */
1011 	if (dev->driver_info->link_reset)
1012 		dev->driver_info->link_reset(dev);
1013 
1014 	/* hard_mtu or rx_urb_size may change in link_reset() */
1015 	usbnet_update_max_qlen(dev);
1016 
1017 	return retval;
1018 }
1019 EXPORT_SYMBOL_GPL(usbnet_set_link_ksettings_mii);
1020 
1021 u32 usbnet_get_link (struct net_device *net)
1022 {
1023 	struct usbnet *dev = netdev_priv(net);
1024 
1025 	/* If a check_connect is defined, return its result */
1026 	if (dev->driver_info->check_connect)
1027 		return dev->driver_info->check_connect (dev) == 0;
1028 
1029 	/* if the device has mii operations, use those */
1030 	if (dev->mii.mdio_read)
1031 		return mii_link_ok(&dev->mii);
1032 
1033 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
1034 	return ethtool_op_get_link(net);
1035 }
1036 EXPORT_SYMBOL_GPL(usbnet_get_link);
1037 
1038 int usbnet_nway_reset(struct net_device *net)
1039 {
1040 	struct usbnet *dev = netdev_priv(net);
1041 
1042 	if (!dev->mii.mdio_write)
1043 		return -EOPNOTSUPP;
1044 
1045 	return mii_nway_restart(&dev->mii);
1046 }
1047 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
1048 
1049 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
1050 {
1051 	struct usbnet *dev = netdev_priv(net);
1052 
1053 	strscpy(info->driver, dev->driver_name, sizeof(info->driver));
1054 	strscpy(info->fw_version, dev->driver_info->description,
1055 		sizeof(info->fw_version));
1056 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
1057 }
1058 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
1059 
1060 u32 usbnet_get_msglevel (struct net_device *net)
1061 {
1062 	struct usbnet *dev = netdev_priv(net);
1063 
1064 	return dev->msg_enable;
1065 }
1066 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
1067 
1068 void usbnet_set_msglevel (struct net_device *net, u32 level)
1069 {
1070 	struct usbnet *dev = netdev_priv(net);
1071 
1072 	dev->msg_enable = level;
1073 }
1074 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
1075 
1076 /* drivers may override default ethtool_ops in their bind() routine */
1077 static const struct ethtool_ops usbnet_ethtool_ops = {
1078 	.get_link		= usbnet_get_link,
1079 	.nway_reset		= usbnet_nway_reset,
1080 	.get_drvinfo		= usbnet_get_drvinfo,
1081 	.get_msglevel		= usbnet_get_msglevel,
1082 	.set_msglevel		= usbnet_set_msglevel,
1083 	.get_ts_info		= ethtool_op_get_ts_info,
1084 	.get_link_ksettings	= usbnet_get_link_ksettings_mii,
1085 	.set_link_ksettings	= usbnet_set_link_ksettings_mii,
1086 };
1087 
1088 /*-------------------------------------------------------------------------*/
1089 
1090 static void __handle_link_change(struct usbnet *dev)
1091 {
1092 	if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
1093 		return;
1094 
1095 	if (!netif_carrier_ok(dev->net)) {
1096 		/* kill URBs for reading packets to save bus bandwidth */
1097 		unlink_urbs(dev, &dev->rxq);
1098 
1099 		/*
1100 		 * tx_timeout will unlink URBs for sending packets and
1101 		 * tx queue is stopped by netcore after link becomes off
1102 		 */
1103 	} else {
1104 		/* submitting URBs for reading packets */
1105 		tasklet_schedule(&dev->bh);
1106 	}
1107 
1108 	/* hard_mtu or rx_urb_size may change during link change */
1109 	usbnet_update_max_qlen(dev);
1110 
1111 	clear_bit(EVENT_LINK_CHANGE, &dev->flags);
1112 }
1113 
1114 void usbnet_set_rx_mode(struct net_device *net)
1115 {
1116 	struct usbnet		*dev = netdev_priv(net);
1117 
1118 	usbnet_defer_kevent(dev, EVENT_SET_RX_MODE);
1119 }
1120 EXPORT_SYMBOL_GPL(usbnet_set_rx_mode);
1121 
1122 static void __handle_set_rx_mode(struct usbnet *dev)
1123 {
1124 	if (dev->driver_info->set_rx_mode)
1125 		(dev->driver_info->set_rx_mode)(dev);
1126 
1127 	clear_bit(EVENT_SET_RX_MODE, &dev->flags);
1128 }
1129 
1130 /* work that cannot be done in interrupt context uses keventd.
1131  *
1132  * NOTE:  with 2.5 we could do more of this using completion callbacks,
1133  * especially now that control transfers can be queued.
1134  */
1135 static void
1136 usbnet_deferred_kevent (struct work_struct *work)
1137 {
1138 	struct usbnet		*dev =
1139 		container_of(work, struct usbnet, kevent);
1140 	int			status;
1141 
1142 	/* usb_clear_halt() needs a thread context */
1143 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
1144 		unlink_urbs (dev, &dev->txq);
1145 		status = usb_autopm_get_interface(dev->intf);
1146 		if (status < 0)
1147 			goto fail_pipe;
1148 		status = usb_clear_halt (dev->udev, dev->out);
1149 		usb_autopm_put_interface(dev->intf);
1150 		if (status < 0 &&
1151 		    status != -EPIPE &&
1152 		    status != -ESHUTDOWN) {
1153 			if (netif_msg_tx_err (dev))
1154 fail_pipe:
1155 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
1156 					   status);
1157 		} else {
1158 			clear_bit (EVENT_TX_HALT, &dev->flags);
1159 			if (status != -ESHUTDOWN)
1160 				netif_wake_queue (dev->net);
1161 		}
1162 	}
1163 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
1164 		unlink_urbs (dev, &dev->rxq);
1165 		status = usb_autopm_get_interface(dev->intf);
1166 		if (status < 0)
1167 			goto fail_halt;
1168 		status = usb_clear_halt (dev->udev, dev->in);
1169 		usb_autopm_put_interface(dev->intf);
1170 		if (status < 0 &&
1171 		    status != -EPIPE &&
1172 		    status != -ESHUTDOWN) {
1173 			if (netif_msg_rx_err (dev))
1174 fail_halt:
1175 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
1176 					   status);
1177 		} else {
1178 			clear_bit (EVENT_RX_HALT, &dev->flags);
1179 			tasklet_schedule (&dev->bh);
1180 		}
1181 	}
1182 
1183 	/* tasklet could resubmit itself forever if memory is tight */
1184 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
1185 		struct urb	*urb = NULL;
1186 		int resched = 1;
1187 
1188 		if (netif_running (dev->net))
1189 			urb = usb_alloc_urb (0, GFP_KERNEL);
1190 		else
1191 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1192 		if (urb != NULL) {
1193 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1194 			status = usb_autopm_get_interface(dev->intf);
1195 			if (status < 0) {
1196 				usb_free_urb(urb);
1197 				goto fail_lowmem;
1198 			}
1199 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
1200 				resched = 0;
1201 			usb_autopm_put_interface(dev->intf);
1202 fail_lowmem:
1203 			if (resched)
1204 				tasklet_schedule (&dev->bh);
1205 		}
1206 	}
1207 
1208 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
1209 		const struct driver_info *info = dev->driver_info;
1210 		int			retval = 0;
1211 
1212 		clear_bit (EVENT_LINK_RESET, &dev->flags);
1213 		status = usb_autopm_get_interface(dev->intf);
1214 		if (status < 0)
1215 			goto skip_reset;
1216 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1217 			usb_autopm_put_interface(dev->intf);
1218 skip_reset:
1219 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1220 				    retval,
1221 				    dev->udev->bus->bus_name,
1222 				    dev->udev->devpath,
1223 				    info->description);
1224 		} else {
1225 			usb_autopm_put_interface(dev->intf);
1226 		}
1227 
1228 		/* handle link change from link resetting */
1229 		__handle_link_change(dev);
1230 	}
1231 
1232 	if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
1233 		__handle_link_change(dev);
1234 
1235 	if (test_bit (EVENT_SET_RX_MODE, &dev->flags))
1236 		__handle_set_rx_mode(dev);
1237 
1238 
1239 	if (dev->flags)
1240 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1241 }
1242 
1243 /*-------------------------------------------------------------------------*/
1244 
1245 static void tx_complete (struct urb *urb)
1246 {
1247 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1248 	struct skb_data		*entry = (struct skb_data *) skb->cb;
1249 	struct usbnet		*dev = entry->dev;
1250 
1251 	if (urb->status == 0) {
1252 		struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->net->tstats);
1253 		unsigned long flags;
1254 
1255 		flags = u64_stats_update_begin_irqsave(&stats64->syncp);
1256 		u64_stats_add(&stats64->tx_packets, entry->packets);
1257 		u64_stats_add(&stats64->tx_bytes, entry->length);
1258 		u64_stats_update_end_irqrestore(&stats64->syncp, flags);
1259 	} else {
1260 		dev->net->stats.tx_errors++;
1261 
1262 		switch (urb->status) {
1263 		case -EPIPE:
1264 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1265 			break;
1266 
1267 		/* software-driven interface shutdown */
1268 		case -ECONNRESET:		// async unlink
1269 		case -ESHUTDOWN:		// hardware gone
1270 			break;
1271 
1272 		/* like rx, tx gets controller i/o faults during hub_wq
1273 		 * delays and so it uses the same throttling mechanism.
1274 		 */
1275 		case -EPROTO:
1276 		case -ETIME:
1277 		case -EILSEQ:
1278 			usb_mark_last_busy(dev->udev);
1279 			if (!timer_pending (&dev->delay)) {
1280 				mod_timer (&dev->delay,
1281 					jiffies + THROTTLE_JIFFIES);
1282 				netif_dbg(dev, link, dev->net,
1283 					  "tx throttle %d\n", urb->status);
1284 			}
1285 			netif_stop_queue (dev->net);
1286 			break;
1287 		default:
1288 			netif_dbg(dev, tx_err, dev->net,
1289 				  "tx err %d\n", entry->urb->status);
1290 			break;
1291 		}
1292 	}
1293 
1294 	usb_autopm_put_interface_async(dev->intf);
1295 	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1296 }
1297 
1298 /*-------------------------------------------------------------------------*/
1299 
1300 void usbnet_tx_timeout (struct net_device *net, unsigned int txqueue)
1301 {
1302 	struct usbnet		*dev = netdev_priv(net);
1303 
1304 	unlink_urbs (dev, &dev->txq);
1305 	tasklet_schedule (&dev->bh);
1306 	/* this needs to be handled individually because the generic layer
1307 	 * doesn't know what is sufficient and could not restore private
1308 	 * information if a remedy of an unconditional reset were used.
1309 	 */
1310 	if (dev->driver_info->recover)
1311 		(dev->driver_info->recover)(dev);
1312 }
1313 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1314 
1315 /*-------------------------------------------------------------------------*/
1316 
1317 static int build_dma_sg(const struct sk_buff *skb, struct urb *urb)
1318 {
1319 	unsigned num_sgs, total_len = 0;
1320 	int i, s = 0;
1321 
1322 	num_sgs = skb_shinfo(skb)->nr_frags + 1;
1323 	if (num_sgs == 1)
1324 		return 0;
1325 
1326 	/* reserve one for zero packet */
1327 	urb->sg = kmalloc_array(num_sgs + 1, sizeof(struct scatterlist),
1328 				GFP_ATOMIC);
1329 	if (!urb->sg)
1330 		return -ENOMEM;
1331 
1332 	urb->num_sgs = num_sgs;
1333 	sg_init_table(urb->sg, urb->num_sgs + 1);
1334 
1335 	sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb));
1336 	total_len += skb_headlen(skb);
1337 
1338 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1339 		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
1340 
1341 		total_len += skb_frag_size(f);
1342 		sg_set_page(&urb->sg[i + s], skb_frag_page(f), skb_frag_size(f),
1343 			    skb_frag_off(f));
1344 	}
1345 	urb->transfer_buffer_length = total_len;
1346 
1347 	return 1;
1348 }
1349 
1350 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1351 				     struct net_device *net)
1352 {
1353 	struct usbnet		*dev = netdev_priv(net);
1354 	unsigned int			length;
1355 	struct urb		*urb = NULL;
1356 	struct skb_data		*entry;
1357 	const struct driver_info *info = dev->driver_info;
1358 	unsigned long		flags;
1359 	int retval;
1360 
1361 	if (skb)
1362 		skb_tx_timestamp(skb);
1363 
1364 	// some devices want funky USB-level framing, for
1365 	// win32 driver (usually) and/or hardware quirks
1366 	if (info->tx_fixup) {
1367 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1368 		if (!skb) {
1369 			/* packet collected; minidriver waiting for more */
1370 			if (info->flags & FLAG_MULTI_PACKET)
1371 				goto not_drop;
1372 			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1373 			goto drop;
1374 		}
1375 	}
1376 
1377 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1378 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1379 		goto drop;
1380 	}
1381 
1382 	entry = (struct skb_data *) skb->cb;
1383 	entry->urb = urb;
1384 	entry->dev = dev;
1385 
1386 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1387 			skb->data, skb->len, tx_complete, skb);
1388 	if (dev->can_dma_sg) {
1389 		if (build_dma_sg(skb, urb) < 0)
1390 			goto drop;
1391 	}
1392 	length = urb->transfer_buffer_length;
1393 
1394 	/* don't assume the hardware handles USB_ZERO_PACKET
1395 	 * NOTE:  strictly conforming cdc-ether devices should expect
1396 	 * the ZLP here, but ignore the one-byte packet.
1397 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1398 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1399 	 * packet itself if needed.
1400 	 */
1401 	if (length % dev->maxpacket == 0) {
1402 		if (!(info->flags & FLAG_SEND_ZLP)) {
1403 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1404 				length++;
1405 				if (skb_tailroom(skb) && !urb->num_sgs) {
1406 					skb->data[skb->len] = 0;
1407 					__skb_put(skb, 1);
1408 				} else if (urb->num_sgs)
1409 					sg_set_buf(&urb->sg[urb->num_sgs++],
1410 							dev->padding_pkt, 1);
1411 			}
1412 		} else
1413 			urb->transfer_flags |= URB_ZERO_PACKET;
1414 	}
1415 	urb->transfer_buffer_length = length;
1416 
1417 	if (info->flags & FLAG_MULTI_PACKET) {
1418 		/* Driver has set number of packets and a length delta.
1419 		 * Calculate the complete length and ensure that it's
1420 		 * positive.
1421 		 */
1422 		entry->length += length;
1423 		if (WARN_ON_ONCE(entry->length <= 0))
1424 			entry->length = length;
1425 	} else {
1426 		usbnet_set_skb_tx_stats(skb, 1, length);
1427 	}
1428 
1429 	spin_lock_irqsave(&dev->txq.lock, flags);
1430 	retval = usb_autopm_get_interface_async(dev->intf);
1431 	if (retval < 0) {
1432 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1433 		goto drop;
1434 	}
1435 	if (netif_queue_stopped(net)) {
1436 		usb_autopm_put_interface_async(dev->intf);
1437 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1438 		goto drop;
1439 	}
1440 
1441 #ifdef CONFIG_PM
1442 	/* if this triggers the device is still a sleep */
1443 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1444 		/* transmission will be done in resume */
1445 		usb_anchor_urb(urb, &dev->deferred);
1446 		/* no use to process more packets */
1447 		netif_stop_queue(net);
1448 		usb_put_urb(urb);
1449 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1450 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1451 		goto deferred;
1452 	}
1453 #endif
1454 
1455 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1456 	case -EPIPE:
1457 		netif_stop_queue (net);
1458 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1459 		usb_autopm_put_interface_async(dev->intf);
1460 		break;
1461 	default:
1462 		usb_autopm_put_interface_async(dev->intf);
1463 		netif_dbg(dev, tx_err, dev->net,
1464 			  "tx: submit urb err %d\n", retval);
1465 		break;
1466 	case 0:
1467 		netif_trans_update(net);
1468 		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1469 		if (dev->txq.qlen >= TX_QLEN (dev))
1470 			netif_stop_queue (net);
1471 	}
1472 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1473 
1474 	if (retval) {
1475 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1476 drop:
1477 		dev->net->stats.tx_dropped++;
1478 not_drop:
1479 		if (skb)
1480 			dev_kfree_skb_any (skb);
1481 		if (urb) {
1482 			kfree(urb->sg);
1483 			usb_free_urb(urb);
1484 		}
1485 	} else
1486 		netif_dbg(dev, tx_queued, dev->net,
1487 			  "> tx, len %u, type 0x%x\n", length, skb->protocol);
1488 #ifdef CONFIG_PM
1489 deferred:
1490 #endif
1491 	return NETDEV_TX_OK;
1492 }
1493 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1494 
1495 static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1496 {
1497 	struct urb	*urb;
1498 	int		i;
1499 	int		ret = 0;
1500 
1501 	/* don't refill the queue all at once */
1502 	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1503 		urb = usb_alloc_urb(0, flags);
1504 		if (urb != NULL) {
1505 			ret = rx_submit(dev, urb, flags);
1506 			if (ret)
1507 				goto err;
1508 		} else {
1509 			ret = -ENOMEM;
1510 			goto err;
1511 		}
1512 	}
1513 err:
1514 	return ret;
1515 }
1516 
1517 /*-------------------------------------------------------------------------*/
1518 
1519 // tasklet (work deferred from completions, in_irq) or timer
1520 
1521 static void usbnet_bh (struct timer_list *t)
1522 {
1523 	struct usbnet		*dev = from_timer(dev, t, delay);
1524 	struct sk_buff		*skb;
1525 	struct skb_data		*entry;
1526 
1527 	while ((skb = skb_dequeue (&dev->done))) {
1528 		entry = (struct skb_data *) skb->cb;
1529 		switch (entry->state) {
1530 		case rx_done:
1531 			entry->state = rx_cleanup;
1532 			rx_process (dev, skb);
1533 			continue;
1534 		case tx_done:
1535 			kfree(entry->urb->sg);
1536 			fallthrough;
1537 		case rx_cleanup:
1538 			usb_free_urb (entry->urb);
1539 			dev_kfree_skb (skb);
1540 			continue;
1541 		default:
1542 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1543 		}
1544 	}
1545 
1546 	/* restart RX again after disabling due to high error rate */
1547 	clear_bit(EVENT_RX_KILL, &dev->flags);
1548 
1549 	/* waiting for all pending urbs to complete?
1550 	 * only then can we forgo submitting anew
1551 	 */
1552 	if (waitqueue_active(&dev->wait)) {
1553 		if (dev->txq.qlen + dev->rxq.qlen + dev->done.qlen == 0)
1554 			wake_up_all(&dev->wait);
1555 
1556 	// or are we maybe short a few urbs?
1557 	} else if (netif_running (dev->net) &&
1558 		   netif_device_present (dev->net) &&
1559 		   netif_carrier_ok(dev->net) &&
1560 		   !timer_pending(&dev->delay) &&
1561 		   !test_bit(EVENT_RX_PAUSED, &dev->flags) &&
1562 		   !test_bit(EVENT_RX_HALT, &dev->flags)) {
1563 		int	temp = dev->rxq.qlen;
1564 
1565 		if (temp < RX_QLEN(dev)) {
1566 			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1567 				return;
1568 			if (temp != dev->rxq.qlen)
1569 				netif_dbg(dev, link, dev->net,
1570 					  "rxqlen %d --> %d\n",
1571 					  temp, dev->rxq.qlen);
1572 			if (dev->rxq.qlen < RX_QLEN(dev))
1573 				tasklet_schedule (&dev->bh);
1574 		}
1575 		if (dev->txq.qlen < TX_QLEN (dev))
1576 			netif_wake_queue (dev->net);
1577 	}
1578 }
1579 
1580 static void usbnet_bh_tasklet(struct tasklet_struct *t)
1581 {
1582 	struct usbnet *dev = from_tasklet(dev, t, bh);
1583 
1584 	usbnet_bh(&dev->delay);
1585 }
1586 
1587 
1588 /*-------------------------------------------------------------------------
1589  *
1590  * USB Device Driver support
1591  *
1592  *-------------------------------------------------------------------------*/
1593 
1594 // precondition: never called in_interrupt
1595 
1596 void usbnet_disconnect (struct usb_interface *intf)
1597 {
1598 	struct usbnet		*dev;
1599 	struct usb_device	*xdev;
1600 	struct net_device	*net;
1601 	struct urb		*urb;
1602 
1603 	dev = usb_get_intfdata(intf);
1604 	usb_set_intfdata(intf, NULL);
1605 	if (!dev)
1606 		return;
1607 
1608 	xdev = interface_to_usbdev (intf);
1609 
1610 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1611 		   intf->dev.driver->name,
1612 		   xdev->bus->bus_name, xdev->devpath,
1613 		   dev->driver_info->description);
1614 
1615 	net = dev->net;
1616 	unregister_netdev (net);
1617 
1618 	while ((urb = usb_get_from_anchor(&dev->deferred))) {
1619 		dev_kfree_skb(urb->context);
1620 		kfree(urb->sg);
1621 		usb_free_urb(urb);
1622 	}
1623 
1624 	if (dev->driver_info->unbind)
1625 		dev->driver_info->unbind(dev, intf);
1626 
1627 	usb_kill_urb(dev->interrupt);
1628 	usb_free_urb(dev->interrupt);
1629 	kfree(dev->padding_pkt);
1630 
1631 	free_percpu(net->tstats);
1632 	free_netdev(net);
1633 }
1634 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1635 
1636 static const struct net_device_ops usbnet_netdev_ops = {
1637 	.ndo_open		= usbnet_open,
1638 	.ndo_stop		= usbnet_stop,
1639 	.ndo_start_xmit		= usbnet_start_xmit,
1640 	.ndo_tx_timeout		= usbnet_tx_timeout,
1641 	.ndo_set_rx_mode	= usbnet_set_rx_mode,
1642 	.ndo_change_mtu		= usbnet_change_mtu,
1643 	.ndo_get_stats64	= dev_get_tstats64,
1644 	.ndo_set_mac_address 	= eth_mac_addr,
1645 	.ndo_validate_addr	= eth_validate_addr,
1646 };
1647 
1648 /*-------------------------------------------------------------------------*/
1649 
1650 // precondition: never called in_interrupt
1651 
1652 static struct device_type wlan_type = {
1653 	.name	= "wlan",
1654 };
1655 
1656 static struct device_type wwan_type = {
1657 	.name	= "wwan",
1658 };
1659 
1660 int
1661 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1662 {
1663 	struct usbnet			*dev;
1664 	struct net_device		*net;
1665 	struct usb_host_interface	*interface;
1666 	const struct driver_info	*info;
1667 	struct usb_device		*xdev;
1668 	int				status;
1669 	const char			*name;
1670 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1671 
1672 	/* usbnet already took usb runtime pm, so have to enable the feature
1673 	 * for usb interface, otherwise usb_autopm_get_interface may return
1674 	 * failure if RUNTIME_PM is enabled.
1675 	 */
1676 	if (!driver->supports_autosuspend) {
1677 		driver->supports_autosuspend = 1;
1678 		pm_runtime_enable(&udev->dev);
1679 	}
1680 
1681 	name = udev->dev.driver->name;
1682 	info = (const struct driver_info *) prod->driver_info;
1683 	if (!info) {
1684 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1685 		return -ENODEV;
1686 	}
1687 	xdev = interface_to_usbdev (udev);
1688 	interface = udev->cur_altsetting;
1689 
1690 	status = -ENOMEM;
1691 
1692 	// set up our own records
1693 	net = alloc_etherdev(sizeof(*dev));
1694 	if (!net)
1695 		goto out;
1696 
1697 	/* netdev_printk() needs this so do it as early as possible */
1698 	SET_NETDEV_DEV(net, &udev->dev);
1699 
1700 	dev = netdev_priv(net);
1701 	dev->udev = xdev;
1702 	dev->intf = udev;
1703 	dev->driver_info = info;
1704 	dev->driver_name = name;
1705 	dev->rx_speed = SPEED_UNSET;
1706 	dev->tx_speed = SPEED_UNSET;
1707 
1708 	net->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1709 	if (!net->tstats)
1710 		goto out0;
1711 
1712 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1713 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1714 	init_waitqueue_head(&dev->wait);
1715 	skb_queue_head_init (&dev->rxq);
1716 	skb_queue_head_init (&dev->txq);
1717 	skb_queue_head_init (&dev->done);
1718 	skb_queue_head_init(&dev->rxq_pause);
1719 	tasklet_setup(&dev->bh, usbnet_bh_tasklet);
1720 	INIT_WORK (&dev->kevent, usbnet_deferred_kevent);
1721 	init_usb_anchor(&dev->deferred);
1722 	timer_setup(&dev->delay, usbnet_bh, 0);
1723 	mutex_init (&dev->phy_mutex);
1724 	mutex_init(&dev->interrupt_mutex);
1725 	dev->interrupt_count = 0;
1726 
1727 	dev->net = net;
1728 	strscpy(net->name, "usb%d", sizeof(net->name));
1729 	eth_hw_addr_set(net, node_id);
1730 
1731 	/* rx and tx sides can use different message sizes;
1732 	 * bind() should set rx_urb_size in that case.
1733 	 */
1734 	dev->hard_mtu = net->mtu + net->hard_header_len;
1735 	net->min_mtu = 0;
1736 	net->max_mtu = ETH_MAX_MTU;
1737 
1738 	net->netdev_ops = &usbnet_netdev_ops;
1739 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1740 	net->ethtool_ops = &usbnet_ethtool_ops;
1741 
1742 	// allow device-specific bind/init procedures
1743 	// NOTE net->name still not usable ...
1744 	if (info->bind) {
1745 		status = info->bind (dev, udev);
1746 		if (status < 0)
1747 			goto out1;
1748 
1749 		// heuristic:  "usb%d" for links we know are two-host,
1750 		// else "eth%d" when there's reasonable doubt.  userspace
1751 		// can rename the link if it knows better.
1752 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1753 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1754 		     (net->dev_addr [0] & 0x02) == 0))
1755 			strscpy(net->name, "eth%d", sizeof(net->name));
1756 		/* WLAN devices should always be named "wlan%d" */
1757 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1758 			strscpy(net->name, "wlan%d", sizeof(net->name));
1759 		/* WWAN devices should always be named "wwan%d" */
1760 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1761 			strscpy(net->name, "wwan%d", sizeof(net->name));
1762 
1763 		/* devices that cannot do ARP */
1764 		if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1765 			net->flags |= IFF_NOARP;
1766 
1767 		/* maybe the remote can't receive an Ethernet MTU */
1768 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1769 			net->mtu = dev->hard_mtu - net->hard_header_len;
1770 	} else if (!info->in || !info->out)
1771 		status = usbnet_get_endpoints (dev, udev);
1772 	else {
1773 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1774 		dev->out = usb_sndbulkpipe (xdev, info->out);
1775 		if (!(info->flags & FLAG_NO_SETINT))
1776 			status = usb_set_interface (xdev,
1777 				interface->desc.bInterfaceNumber,
1778 				interface->desc.bAlternateSetting);
1779 		else
1780 			status = 0;
1781 
1782 	}
1783 	if (status >= 0 && dev->status)
1784 		status = init_status (dev, udev);
1785 	if (status < 0)
1786 		goto out3;
1787 
1788 	if (!dev->rx_urb_size)
1789 		dev->rx_urb_size = dev->hard_mtu;
1790 	dev->maxpacket = usb_maxpacket(dev->udev, dev->out);
1791 	if (dev->maxpacket == 0) {
1792 		/* that is a broken device */
1793 		status = -ENODEV;
1794 		goto out4;
1795 	}
1796 
1797 	/* let userspace know we have a random address */
1798 	if (ether_addr_equal(net->dev_addr, node_id))
1799 		net->addr_assign_type = NET_ADDR_RANDOM;
1800 
1801 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1802 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1803 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1804 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1805 
1806 	/* initialize max rx_qlen and tx_qlen */
1807 	usbnet_update_max_qlen(dev);
1808 
1809 	if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&
1810 		!(info->flags & FLAG_MULTI_PACKET)) {
1811 		dev->padding_pkt = kzalloc(1, GFP_KERNEL);
1812 		if (!dev->padding_pkt) {
1813 			status = -ENOMEM;
1814 			goto out4;
1815 		}
1816 	}
1817 
1818 	status = register_netdev (net);
1819 	if (status)
1820 		goto out5;
1821 	netif_info(dev, probe, dev->net,
1822 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1823 		   udev->dev.driver->name,
1824 		   xdev->bus->bus_name, xdev->devpath,
1825 		   dev->driver_info->description,
1826 		   net->dev_addr);
1827 
1828 	// ok, it's ready to go.
1829 	usb_set_intfdata (udev, dev);
1830 
1831 	netif_device_attach (net);
1832 
1833 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1834 		usbnet_link_change(dev, 0, 0);
1835 
1836 	return 0;
1837 
1838 out5:
1839 	kfree(dev->padding_pkt);
1840 out4:
1841 	usb_free_urb(dev->interrupt);
1842 out3:
1843 	if (info->unbind)
1844 		info->unbind (dev, udev);
1845 out1:
1846 	/* subdrivers must undo all they did in bind() if they
1847 	 * fail it, but we may fail later and a deferred kevent
1848 	 * may trigger an error resubmitting itself and, worse,
1849 	 * schedule a timer. So we kill it all just in case.
1850 	 */
1851 	cancel_work_sync(&dev->kevent);
1852 	del_timer_sync(&dev->delay);
1853 	free_percpu(net->tstats);
1854 out0:
1855 	free_netdev(net);
1856 out:
1857 	return status;
1858 }
1859 EXPORT_SYMBOL_GPL(usbnet_probe);
1860 
1861 /*-------------------------------------------------------------------------*/
1862 
1863 /*
1864  * suspend the whole driver as soon as the first interface is suspended
1865  * resume only when the last interface is resumed
1866  */
1867 
1868 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1869 {
1870 	struct usbnet		*dev = usb_get_intfdata(intf);
1871 
1872 	if (!dev->suspend_count++) {
1873 		spin_lock_irq(&dev->txq.lock);
1874 		/* don't autosuspend while transmitting */
1875 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1876 			dev->suspend_count--;
1877 			spin_unlock_irq(&dev->txq.lock);
1878 			return -EBUSY;
1879 		} else {
1880 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1881 			spin_unlock_irq(&dev->txq.lock);
1882 		}
1883 		/*
1884 		 * accelerate emptying of the rx and queues, to avoid
1885 		 * having everything error out.
1886 		 */
1887 		netif_device_detach (dev->net);
1888 		usbnet_terminate_urbs(dev);
1889 		__usbnet_status_stop_force(dev);
1890 
1891 		/*
1892 		 * reattach so runtime management can use and
1893 		 * wake the device
1894 		 */
1895 		netif_device_attach (dev->net);
1896 	}
1897 	return 0;
1898 }
1899 EXPORT_SYMBOL_GPL(usbnet_suspend);
1900 
1901 int usbnet_resume (struct usb_interface *intf)
1902 {
1903 	struct usbnet		*dev = usb_get_intfdata(intf);
1904 	struct sk_buff          *skb;
1905 	struct urb              *res;
1906 	int                     retval;
1907 
1908 	if (!--dev->suspend_count) {
1909 		/* resume interrupt URB if it was previously submitted */
1910 		__usbnet_status_start_force(dev, GFP_NOIO);
1911 
1912 		spin_lock_irq(&dev->txq.lock);
1913 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1914 
1915 			skb = (struct sk_buff *)res->context;
1916 			retval = usb_submit_urb(res, GFP_ATOMIC);
1917 			if (retval < 0) {
1918 				dev_kfree_skb_any(skb);
1919 				kfree(res->sg);
1920 				usb_free_urb(res);
1921 				usb_autopm_put_interface_async(dev->intf);
1922 			} else {
1923 				netif_trans_update(dev->net);
1924 				__skb_queue_tail(&dev->txq, skb);
1925 			}
1926 		}
1927 
1928 		smp_mb();
1929 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1930 		spin_unlock_irq(&dev->txq.lock);
1931 
1932 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1933 			/* handle remote wakeup ASAP
1934 			 * we cannot race against stop
1935 			 */
1936 			if (netif_device_present(dev->net) &&
1937 				!timer_pending(&dev->delay) &&
1938 				!test_bit(EVENT_RX_HALT, &dev->flags))
1939 					rx_alloc_submit(dev, GFP_NOIO);
1940 
1941 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1942 				netif_tx_wake_all_queues(dev->net);
1943 			tasklet_schedule (&dev->bh);
1944 		}
1945 	}
1946 
1947 	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1948 		usb_autopm_get_interface_no_resume(intf);
1949 
1950 	return 0;
1951 }
1952 EXPORT_SYMBOL_GPL(usbnet_resume);
1953 
1954 /*
1955  * Either a subdriver implements manage_power, then it is assumed to always
1956  * be ready to be suspended or it reports the readiness to be suspended
1957  * explicitly
1958  */
1959 void usbnet_device_suggests_idle(struct usbnet *dev)
1960 {
1961 	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1962 		dev->intf->needs_remote_wakeup = 1;
1963 		usb_autopm_put_interface_async(dev->intf);
1964 	}
1965 }
1966 EXPORT_SYMBOL(usbnet_device_suggests_idle);
1967 
1968 /*
1969  * For devices that can do without special commands
1970  */
1971 int usbnet_manage_power(struct usbnet *dev, int on)
1972 {
1973 	dev->intf->needs_remote_wakeup = on;
1974 	return 0;
1975 }
1976 EXPORT_SYMBOL(usbnet_manage_power);
1977 
1978 void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
1979 {
1980 	/* update link after link is reseted */
1981 	if (link && !need_reset)
1982 		netif_carrier_on(dev->net);
1983 	else
1984 		netif_carrier_off(dev->net);
1985 
1986 	if (need_reset && link)
1987 		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
1988 	else
1989 		usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
1990 }
1991 EXPORT_SYMBOL(usbnet_link_change);
1992 
1993 /*-------------------------------------------------------------------------*/
1994 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1995 			     u16 value, u16 index, void *data, u16 size)
1996 {
1997 	void *buf = NULL;
1998 	int err = -ENOMEM;
1999 
2000 	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
2001 		   " value=0x%04x index=0x%04x size=%d\n",
2002 		   cmd, reqtype, value, index, size);
2003 
2004 	if (size) {
2005 		buf = kmalloc(size, GFP_NOIO);
2006 		if (!buf)
2007 			goto out;
2008 	}
2009 
2010 	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
2011 			      cmd, reqtype, value, index, buf, size,
2012 			      USB_CTRL_GET_TIMEOUT);
2013 	if (err > 0 && err <= size) {
2014 		if (data)
2015 			memcpy(data, buf, err);
2016 		else
2017 			netdev_dbg(dev->net,
2018 				   "Huh? Data requested but thrown away.\n");
2019 	}
2020 	kfree(buf);
2021 out:
2022 	return err;
2023 }
2024 
2025 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2026 			      u16 value, u16 index, const void *data,
2027 			      u16 size)
2028 {
2029 	void *buf = NULL;
2030 	int err = -ENOMEM;
2031 
2032 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2033 		   " value=0x%04x index=0x%04x size=%d\n",
2034 		   cmd, reqtype, value, index, size);
2035 
2036 	if (data) {
2037 		buf = kmemdup(data, size, GFP_NOIO);
2038 		if (!buf)
2039 			goto out;
2040 	} else {
2041         if (size) {
2042             WARN_ON_ONCE(1);
2043             err = -EINVAL;
2044             goto out;
2045         }
2046     }
2047 
2048 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
2049 			      cmd, reqtype, value, index, buf, size,
2050 			      USB_CTRL_SET_TIMEOUT);
2051 	kfree(buf);
2052 
2053 out:
2054 	return err;
2055 }
2056 
2057 /*
2058  * The function can't be called inside suspend/resume callback,
2059  * otherwise deadlock will be caused.
2060  */
2061 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2062 		    u16 value, u16 index, void *data, u16 size)
2063 {
2064 	int ret;
2065 
2066 	if (usb_autopm_get_interface(dev->intf) < 0)
2067 		return -ENODEV;
2068 	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2069 				data, size);
2070 	usb_autopm_put_interface(dev->intf);
2071 	return ret;
2072 }
2073 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
2074 
2075 /*
2076  * The function can't be called inside suspend/resume callback,
2077  * otherwise deadlock will be caused.
2078  */
2079 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2080 		     u16 value, u16 index, const void *data, u16 size)
2081 {
2082 	int ret;
2083 
2084 	if (usb_autopm_get_interface(dev->intf) < 0)
2085 		return -ENODEV;
2086 	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2087 				 data, size);
2088 	usb_autopm_put_interface(dev->intf);
2089 	return ret;
2090 }
2091 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
2092 
2093 /*
2094  * The function can be called inside suspend/resume callback safely
2095  * and should only be called by suspend/resume callback generally.
2096  */
2097 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2098 			  u16 value, u16 index, void *data, u16 size)
2099 {
2100 	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2101 				 data, size);
2102 }
2103 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
2104 
2105 /*
2106  * The function can be called inside suspend/resume callback safely
2107  * and should only be called by suspend/resume callback generally.
2108  */
2109 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2110 			  u16 value, u16 index, const void *data,
2111 			  u16 size)
2112 {
2113 	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2114 				  data, size);
2115 }
2116 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
2117 
2118 static void usbnet_async_cmd_cb(struct urb *urb)
2119 {
2120 	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
2121 	int status = urb->status;
2122 
2123 	if (status < 0)
2124 		dev_dbg(&urb->dev->dev, "%s failed with %d",
2125 			__func__, status);
2126 
2127 	kfree(req);
2128 	usb_free_urb(urb);
2129 }
2130 
2131 /*
2132  * The caller must make sure that device can't be put into suspend
2133  * state until the control URB completes.
2134  */
2135 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
2136 			   u16 value, u16 index, const void *data, u16 size)
2137 {
2138 	struct usb_ctrlrequest *req;
2139 	struct urb *urb;
2140 	int err = -ENOMEM;
2141 	void *buf = NULL;
2142 
2143 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2144 		   " value=0x%04x index=0x%04x size=%d\n",
2145 		   cmd, reqtype, value, index, size);
2146 
2147 	urb = usb_alloc_urb(0, GFP_ATOMIC);
2148 	if (!urb)
2149 		goto fail;
2150 
2151 	if (data) {
2152 		buf = kmemdup(data, size, GFP_ATOMIC);
2153 		if (!buf) {
2154 			netdev_err(dev->net, "Error allocating buffer"
2155 				   " in %s!\n", __func__);
2156 			goto fail_free_urb;
2157 		}
2158 	}
2159 
2160 	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
2161 	if (!req)
2162 		goto fail_free_buf;
2163 
2164 	req->bRequestType = reqtype;
2165 	req->bRequest = cmd;
2166 	req->wValue = cpu_to_le16(value);
2167 	req->wIndex = cpu_to_le16(index);
2168 	req->wLength = cpu_to_le16(size);
2169 
2170 	usb_fill_control_urb(urb, dev->udev,
2171 			     usb_sndctrlpipe(dev->udev, 0),
2172 			     (void *)req, buf, size,
2173 			     usbnet_async_cmd_cb, req);
2174 	urb->transfer_flags |= URB_FREE_BUFFER;
2175 
2176 	err = usb_submit_urb(urb, GFP_ATOMIC);
2177 	if (err < 0) {
2178 		netdev_err(dev->net, "Error submitting the control"
2179 			   " message: status=%d\n", err);
2180 		goto fail_free_all;
2181 	}
2182 	return 0;
2183 
2184 fail_free_all:
2185 	kfree(req);
2186 fail_free_buf:
2187 	kfree(buf);
2188 	/*
2189 	 * avoid a double free
2190 	 * needed because the flag can be set only
2191 	 * after filling the URB
2192 	 */
2193 	urb->transfer_flags = 0;
2194 fail_free_urb:
2195 	usb_free_urb(urb);
2196 fail:
2197 	return err;
2198 
2199 }
2200 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
2201 /*-------------------------------------------------------------------------*/
2202 
2203 static int __init usbnet_init(void)
2204 {
2205 	/* Compiler should optimize this out. */
2206 	BUILD_BUG_ON(
2207 		sizeof_field(struct sk_buff, cb) < sizeof(struct skb_data));
2208 
2209 	eth_random_addr(node_id);
2210 	return 0;
2211 }
2212 module_init(usbnet_init);
2213 
2214 static void __exit usbnet_exit(void)
2215 {
2216 }
2217 module_exit(usbnet_exit);
2218 
2219 MODULE_AUTHOR("David Brownell");
2220 MODULE_DESCRIPTION("USB network driver framework");
2221 MODULE_LICENSE("GPL");
2222