xref: /linux/drivers/net/usb/usbnet.c (revision 41f7adb676f6c4aef439d78b15c7e1119216bc2b)
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 	WRITE_ONCE(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 int 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 		return -EPROTO;
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 		return -EALREADY;
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 		return -EPROTO;
578 	}
579 
580 	usbnet_skb_return(dev, skb);
581 	return 0;
582 }
583 
584 /*-------------------------------------------------------------------------*/
585 
586 static void rx_complete (struct urb *urb)
587 {
588 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
589 	struct skb_data		*entry = (struct skb_data *) skb->cb;
590 	struct usbnet		*dev = entry->dev;
591 	int			urb_status = urb->status;
592 	enum skb_state		state;
593 
594 	skb_put (skb, urb->actual_length);
595 	state = rx_done;
596 	entry->urb = NULL;
597 
598 	switch (urb_status) {
599 	/* success */
600 	case 0:
601 		break;
602 
603 	/* stalls need manual reset. this is rare ... except that
604 	 * when going through USB 2.0 TTs, unplug appears this way.
605 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
606 	 * storm, recovering as needed.
607 	 */
608 	case -EPIPE:
609 		dev->net->stats.rx_errors++;
610 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
611 		fallthrough;
612 
613 	/* software-driven interface shutdown */
614 	case -ECONNRESET:		/* async unlink */
615 	case -ESHUTDOWN:		/* hardware gone */
616 		netif_dbg(dev, ifdown, dev->net,
617 			  "rx shutdown, code %d\n", urb_status);
618 		goto block;
619 
620 	/* we get controller i/o faults during hub_wq disconnect() delays.
621 	 * throttle down resubmits, to avoid log floods; just temporarily,
622 	 * so we still recover when the fault isn't a hub_wq delay.
623 	 */
624 	case -EPROTO:
625 	case -ETIME:
626 	case -EILSEQ:
627 		dev->net->stats.rx_errors++;
628 		if (!timer_pending (&dev->delay)) {
629 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
630 			netif_dbg(dev, link, dev->net,
631 				  "rx throttle %d\n", urb_status);
632 		}
633 block:
634 		state = rx_cleanup;
635 		entry->urb = urb;
636 		urb = NULL;
637 		break;
638 
639 	/* data overrun ... flush fifo? */
640 	case -EOVERFLOW:
641 		dev->net->stats.rx_over_errors++;
642 		fallthrough;
643 
644 	default:
645 		state = rx_cleanup;
646 		dev->net->stats.rx_errors++;
647 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
648 		break;
649 	}
650 
651 	/* stop rx if packet error rate is high */
652 	if (++dev->pkt_cnt > 30) {
653 		dev->pkt_cnt = 0;
654 		dev->pkt_err = 0;
655 	} else {
656 		if (state == rx_cleanup)
657 			dev->pkt_err++;
658 		if (dev->pkt_err > 20)
659 			set_bit(EVENT_RX_KILL, &dev->flags);
660 	}
661 
662 	state = defer_bh(dev, skb, &dev->rxq, state);
663 
664 	if (urb) {
665 		if (netif_running (dev->net) &&
666 		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
667 		    state != unlink_start) {
668 			rx_submit (dev, urb, GFP_ATOMIC);
669 			usb_mark_last_busy(dev->udev);
670 			return;
671 		}
672 		usb_free_urb (urb);
673 	}
674 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
675 }
676 
677 /*-------------------------------------------------------------------------*/
678 void usbnet_pause_rx(struct usbnet *dev)
679 {
680 	set_bit(EVENT_RX_PAUSED, &dev->flags);
681 
682 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
683 }
684 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
685 
686 void usbnet_resume_rx(struct usbnet *dev)
687 {
688 	struct sk_buff *skb;
689 	int num = 0;
690 
691 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
692 
693 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
694 		usbnet_skb_return(dev, skb);
695 		num++;
696 	}
697 
698 	tasklet_schedule(&dev->bh);
699 
700 	netif_dbg(dev, rx_status, dev->net,
701 		  "paused rx queue disabled, %d skbs requeued\n", num);
702 }
703 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
704 
705 void usbnet_purge_paused_rxq(struct usbnet *dev)
706 {
707 	skb_queue_purge(&dev->rxq_pause);
708 }
709 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
710 
711 /*-------------------------------------------------------------------------*/
712 
713 // unlink pending rx/tx; completion handlers do all other cleanup
714 
715 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
716 {
717 	unsigned long		flags;
718 	struct sk_buff		*skb;
719 	int			count = 0;
720 
721 	spin_lock_irqsave (&q->lock, flags);
722 	while (!skb_queue_empty(q)) {
723 		struct skb_data		*entry;
724 		struct urb		*urb;
725 		int			retval;
726 
727 		skb_queue_walk(q, skb) {
728 			entry = (struct skb_data *) skb->cb;
729 			if (entry->state != unlink_start)
730 				goto found;
731 		}
732 		break;
733 found:
734 		entry->state = unlink_start;
735 		urb = entry->urb;
736 
737 		/*
738 		 * Get reference count of the URB to avoid it to be
739 		 * freed during usb_unlink_urb, which may trigger
740 		 * use-after-free problem inside usb_unlink_urb since
741 		 * usb_unlink_urb is always racing with .complete
742 		 * handler(include defer_bh).
743 		 */
744 		usb_get_urb(urb);
745 		spin_unlock_irqrestore(&q->lock, flags);
746 		// during some PM-driven resume scenarios,
747 		// these (async) unlinks complete immediately
748 		retval = usb_unlink_urb (urb);
749 		if (retval != -EINPROGRESS && retval != 0)
750 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
751 		else
752 			count++;
753 		usb_put_urb(urb);
754 		spin_lock_irqsave(&q->lock, flags);
755 	}
756 	spin_unlock_irqrestore (&q->lock, flags);
757 	return count;
758 }
759 
760 // Flush all pending rx urbs
761 // minidrivers may need to do this when the MTU changes
762 
763 void usbnet_unlink_rx_urbs(struct usbnet *dev)
764 {
765 	if (netif_running(dev->net)) {
766 		(void) unlink_urbs (dev, &dev->rxq);
767 		tasklet_schedule(&dev->bh);
768 	}
769 }
770 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
771 
772 /*-------------------------------------------------------------------------*/
773 
774 static void wait_skb_queue_empty(struct sk_buff_head *q)
775 {
776 	unsigned long flags;
777 
778 	spin_lock_irqsave(&q->lock, flags);
779 	while (!skb_queue_empty(q)) {
780 		spin_unlock_irqrestore(&q->lock, flags);
781 		schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
782 		set_current_state(TASK_UNINTERRUPTIBLE);
783 		spin_lock_irqsave(&q->lock, flags);
784 	}
785 	spin_unlock_irqrestore(&q->lock, flags);
786 }
787 
788 // precondition: never called in_interrupt
789 static void usbnet_terminate_urbs(struct usbnet *dev)
790 {
791 	DECLARE_WAITQUEUE(wait, current);
792 	int temp;
793 
794 	/* ensure there are no more active urbs */
795 	add_wait_queue(&dev->wait, &wait);
796 	set_current_state(TASK_UNINTERRUPTIBLE);
797 	temp = unlink_urbs(dev, &dev->txq) +
798 		unlink_urbs(dev, &dev->rxq);
799 
800 	/* maybe wait for deletions to finish. */
801 	wait_skb_queue_empty(&dev->rxq);
802 	wait_skb_queue_empty(&dev->txq);
803 	wait_skb_queue_empty(&dev->done);
804 	netif_dbg(dev, ifdown, dev->net,
805 		  "waited for %d urb completions\n", temp);
806 	set_current_state(TASK_RUNNING);
807 	remove_wait_queue(&dev->wait, &wait);
808 }
809 
810 int usbnet_stop (struct net_device *net)
811 {
812 	struct usbnet		*dev = netdev_priv(net);
813 	const struct driver_info *info = dev->driver_info;
814 	int			retval, pm, mpn;
815 
816 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
817 	netif_stop_queue (net);
818 
819 	netif_info(dev, ifdown, dev->net,
820 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
821 		   net->stats.rx_packets, net->stats.tx_packets,
822 		   net->stats.rx_errors, net->stats.tx_errors);
823 
824 	/* to not race resume */
825 	pm = usb_autopm_get_interface(dev->intf);
826 	/* allow minidriver to stop correctly (wireless devices to turn off
827 	 * radio etc) */
828 	if (info->stop) {
829 		retval = info->stop(dev);
830 		if (retval < 0)
831 			netif_info(dev, ifdown, dev->net,
832 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
833 				   retval,
834 				   dev->udev->bus->bus_name, dev->udev->devpath,
835 				   info->description);
836 	}
837 
838 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
839 		usbnet_terminate_urbs(dev);
840 
841 	usbnet_status_stop(dev);
842 
843 	usbnet_purge_paused_rxq(dev);
844 
845 	mpn = !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
846 
847 	/* deferred work (timer, softirq, task) must also stop */
848 	dev->flags = 0;
849 	del_timer_sync (&dev->delay);
850 	tasklet_kill (&dev->bh);
851 	cancel_work_sync(&dev->kevent);
852 	if (!pm)
853 		usb_autopm_put_interface(dev->intf);
854 
855 	if (info->manage_power && mpn)
856 		info->manage_power(dev, 0);
857 	else
858 		usb_autopm_put_interface(dev->intf);
859 
860 	return 0;
861 }
862 EXPORT_SYMBOL_GPL(usbnet_stop);
863 
864 /*-------------------------------------------------------------------------*/
865 
866 // posts reads, and enables write queuing
867 
868 // precondition: never called in_interrupt
869 
870 int usbnet_open (struct net_device *net)
871 {
872 	struct usbnet		*dev = netdev_priv(net);
873 	int			retval;
874 	const struct driver_info *info = dev->driver_info;
875 
876 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
877 		netif_info(dev, ifup, dev->net,
878 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
879 			   retval,
880 			   dev->udev->bus->bus_name,
881 			   dev->udev->devpath,
882 			   info->description);
883 		goto done_nopm;
884 	}
885 
886 	// put into "known safe" state
887 	if (info->reset && (retval = info->reset (dev)) < 0) {
888 		netif_info(dev, ifup, dev->net,
889 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
890 			   retval,
891 			   dev->udev->bus->bus_name,
892 			   dev->udev->devpath,
893 			   info->description);
894 		goto done;
895 	}
896 
897 	/* hard_mtu or rx_urb_size may change in reset() */
898 	usbnet_update_max_qlen(dev);
899 
900 	// insist peer be connected
901 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
902 		netif_err(dev, ifup, dev->net, "can't open; %d\n", retval);
903 		goto done;
904 	}
905 
906 	/* start any status interrupt transfer */
907 	if (dev->interrupt) {
908 		retval = usbnet_status_start(dev, GFP_KERNEL);
909 		if (retval < 0) {
910 			netif_err(dev, ifup, dev->net,
911 				  "intr submit %d\n", retval);
912 			goto done;
913 		}
914 	}
915 
916 	set_bit(EVENT_DEV_OPEN, &dev->flags);
917 	netif_start_queue (net);
918 	netif_info(dev, ifup, dev->net,
919 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
920 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
921 		   dev->net->mtu,
922 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
923 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
924 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
925 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
926 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
927 		   "simple");
928 
929 	/* reset rx error state */
930 	dev->pkt_cnt = 0;
931 	dev->pkt_err = 0;
932 	clear_bit(EVENT_RX_KILL, &dev->flags);
933 
934 	// delay posting reads until we're fully open
935 	tasklet_schedule (&dev->bh);
936 	if (info->manage_power) {
937 		retval = info->manage_power(dev, 1);
938 		if (retval < 0) {
939 			retval = 0;
940 			set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
941 		} else {
942 			usb_autopm_put_interface(dev->intf);
943 		}
944 	}
945 	return retval;
946 done:
947 	usb_autopm_put_interface(dev->intf);
948 done_nopm:
949 	return retval;
950 }
951 EXPORT_SYMBOL_GPL(usbnet_open);
952 
953 /*-------------------------------------------------------------------------*/
954 
955 /* ethtool methods; minidrivers may need to add some more, but
956  * they'll probably want to use this base set.
957  */
958 
959 /* These methods are written on the assumption that the device
960  * uses MII
961  */
962 int usbnet_get_link_ksettings_mii(struct net_device *net,
963 			      struct ethtool_link_ksettings *cmd)
964 {
965 	struct usbnet *dev = netdev_priv(net);
966 
967 	if (!dev->mii.mdio_read)
968 		return -EOPNOTSUPP;
969 
970 	mii_ethtool_get_link_ksettings(&dev->mii, cmd);
971 
972 	return 0;
973 }
974 EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings_mii);
975 
976 int usbnet_get_link_ksettings_internal(struct net_device *net,
977 					struct ethtool_link_ksettings *cmd)
978 {
979 	struct usbnet *dev = netdev_priv(net);
980 
981 	/* the assumption that speed is equal on tx and rx
982 	 * is deeply engrained into the networking layer.
983 	 * For wireless stuff it is not true.
984 	 * We assume that rx_speed matters more.
985 	 */
986 	if (dev->rx_speed != SPEED_UNSET)
987 		cmd->base.speed = dev->rx_speed / 1000000;
988 	else if (dev->tx_speed != SPEED_UNSET)
989 		cmd->base.speed = dev->tx_speed / 1000000;
990 	else
991 		cmd->base.speed = SPEED_UNKNOWN;
992 
993 	return 0;
994 }
995 EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings_internal);
996 
997 int usbnet_set_link_ksettings_mii(struct net_device *net,
998 			      const struct ethtool_link_ksettings *cmd)
999 {
1000 	struct usbnet *dev = netdev_priv(net);
1001 	int retval;
1002 
1003 	if (!dev->mii.mdio_write)
1004 		return -EOPNOTSUPP;
1005 
1006 	retval = mii_ethtool_set_link_ksettings(&dev->mii, cmd);
1007 
1008 	/* link speed/duplex might have changed */
1009 	if (dev->driver_info->link_reset)
1010 		dev->driver_info->link_reset(dev);
1011 
1012 	/* hard_mtu or rx_urb_size may change in link_reset() */
1013 	usbnet_update_max_qlen(dev);
1014 
1015 	return retval;
1016 }
1017 EXPORT_SYMBOL_GPL(usbnet_set_link_ksettings_mii);
1018 
1019 u32 usbnet_get_link (struct net_device *net)
1020 {
1021 	struct usbnet *dev = netdev_priv(net);
1022 
1023 	/* If a check_connect is defined, return its result */
1024 	if (dev->driver_info->check_connect)
1025 		return dev->driver_info->check_connect (dev) == 0;
1026 
1027 	/* if the device has mii operations, use those */
1028 	if (dev->mii.mdio_read)
1029 		return mii_link_ok(&dev->mii);
1030 
1031 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
1032 	return ethtool_op_get_link(net);
1033 }
1034 EXPORT_SYMBOL_GPL(usbnet_get_link);
1035 
1036 int usbnet_nway_reset(struct net_device *net)
1037 {
1038 	struct usbnet *dev = netdev_priv(net);
1039 
1040 	if (!dev->mii.mdio_write)
1041 		return -EOPNOTSUPP;
1042 
1043 	return mii_nway_restart(&dev->mii);
1044 }
1045 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
1046 
1047 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
1048 {
1049 	struct usbnet *dev = netdev_priv(net);
1050 
1051 	strscpy(info->driver, dev->driver_name, sizeof(info->driver));
1052 	strscpy(info->fw_version, dev->driver_info->description,
1053 		sizeof(info->fw_version));
1054 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
1055 }
1056 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
1057 
1058 u32 usbnet_get_msglevel (struct net_device *net)
1059 {
1060 	struct usbnet *dev = netdev_priv(net);
1061 
1062 	return dev->msg_enable;
1063 }
1064 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
1065 
1066 void usbnet_set_msglevel (struct net_device *net, u32 level)
1067 {
1068 	struct usbnet *dev = netdev_priv(net);
1069 
1070 	dev->msg_enable = level;
1071 }
1072 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
1073 
1074 /* drivers may override default ethtool_ops in their bind() routine */
1075 static const struct ethtool_ops usbnet_ethtool_ops = {
1076 	.get_link		= usbnet_get_link,
1077 	.nway_reset		= usbnet_nway_reset,
1078 	.get_drvinfo		= usbnet_get_drvinfo,
1079 	.get_msglevel		= usbnet_get_msglevel,
1080 	.set_msglevel		= usbnet_set_msglevel,
1081 	.get_ts_info		= ethtool_op_get_ts_info,
1082 	.get_link_ksettings	= usbnet_get_link_ksettings_mii,
1083 	.set_link_ksettings	= usbnet_set_link_ksettings_mii,
1084 };
1085 
1086 /*-------------------------------------------------------------------------*/
1087 
1088 static void __handle_link_change(struct usbnet *dev)
1089 {
1090 	if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
1091 		return;
1092 
1093 	if (!netif_carrier_ok(dev->net)) {
1094 		/* kill URBs for reading packets to save bus bandwidth */
1095 		unlink_urbs(dev, &dev->rxq);
1096 
1097 		/*
1098 		 * tx_timeout will unlink URBs for sending packets and
1099 		 * tx queue is stopped by netcore after link becomes off
1100 		 */
1101 	} else {
1102 		/* submitting URBs for reading packets */
1103 		tasklet_schedule(&dev->bh);
1104 	}
1105 
1106 	/* hard_mtu or rx_urb_size may change during link change */
1107 	usbnet_update_max_qlen(dev);
1108 
1109 	clear_bit(EVENT_LINK_CHANGE, &dev->flags);
1110 }
1111 
1112 void usbnet_set_rx_mode(struct net_device *net)
1113 {
1114 	struct usbnet		*dev = netdev_priv(net);
1115 
1116 	usbnet_defer_kevent(dev, EVENT_SET_RX_MODE);
1117 }
1118 EXPORT_SYMBOL_GPL(usbnet_set_rx_mode);
1119 
1120 static void __handle_set_rx_mode(struct usbnet *dev)
1121 {
1122 	if (dev->driver_info->set_rx_mode)
1123 		(dev->driver_info->set_rx_mode)(dev);
1124 
1125 	clear_bit(EVENT_SET_RX_MODE, &dev->flags);
1126 }
1127 
1128 /* work that cannot be done in interrupt context uses keventd.
1129  *
1130  * NOTE:  with 2.5 we could do more of this using completion callbacks,
1131  * especially now that control transfers can be queued.
1132  */
1133 static void
1134 usbnet_deferred_kevent (struct work_struct *work)
1135 {
1136 	struct usbnet		*dev =
1137 		container_of(work, struct usbnet, kevent);
1138 	int			status;
1139 
1140 	/* usb_clear_halt() needs a thread context */
1141 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
1142 		unlink_urbs (dev, &dev->txq);
1143 		status = usb_autopm_get_interface(dev->intf);
1144 		if (status < 0)
1145 			goto fail_pipe;
1146 		status = usb_clear_halt (dev->udev, dev->out);
1147 		usb_autopm_put_interface(dev->intf);
1148 		if (status < 0 &&
1149 		    status != -EPIPE &&
1150 		    status != -ESHUTDOWN) {
1151 			if (netif_msg_tx_err (dev))
1152 fail_pipe:
1153 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
1154 					   status);
1155 		} else {
1156 			clear_bit (EVENT_TX_HALT, &dev->flags);
1157 			if (status != -ESHUTDOWN)
1158 				netif_wake_queue (dev->net);
1159 		}
1160 	}
1161 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
1162 		unlink_urbs (dev, &dev->rxq);
1163 		status = usb_autopm_get_interface(dev->intf);
1164 		if (status < 0)
1165 			goto fail_halt;
1166 		status = usb_clear_halt (dev->udev, dev->in);
1167 		usb_autopm_put_interface(dev->intf);
1168 		if (status < 0 &&
1169 		    status != -EPIPE &&
1170 		    status != -ESHUTDOWN) {
1171 			if (netif_msg_rx_err (dev))
1172 fail_halt:
1173 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
1174 					   status);
1175 		} else {
1176 			clear_bit (EVENT_RX_HALT, &dev->flags);
1177 			tasklet_schedule (&dev->bh);
1178 		}
1179 	}
1180 
1181 	/* tasklet could resubmit itself forever if memory is tight */
1182 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
1183 		struct urb	*urb = NULL;
1184 		int resched = 1;
1185 
1186 		if (netif_running (dev->net))
1187 			urb = usb_alloc_urb (0, GFP_KERNEL);
1188 		else
1189 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1190 		if (urb != NULL) {
1191 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1192 			status = usb_autopm_get_interface(dev->intf);
1193 			if (status < 0) {
1194 				usb_free_urb(urb);
1195 				goto fail_lowmem;
1196 			}
1197 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
1198 				resched = 0;
1199 			usb_autopm_put_interface(dev->intf);
1200 fail_lowmem:
1201 			if (resched)
1202 				tasklet_schedule (&dev->bh);
1203 		}
1204 	}
1205 
1206 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
1207 		const struct driver_info *info = dev->driver_info;
1208 		int			retval = 0;
1209 
1210 		clear_bit (EVENT_LINK_RESET, &dev->flags);
1211 		status = usb_autopm_get_interface(dev->intf);
1212 		if (status < 0)
1213 			goto skip_reset;
1214 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1215 			usb_autopm_put_interface(dev->intf);
1216 skip_reset:
1217 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1218 				    retval,
1219 				    dev->udev->bus->bus_name,
1220 				    dev->udev->devpath,
1221 				    info->description);
1222 		} else {
1223 			usb_autopm_put_interface(dev->intf);
1224 		}
1225 
1226 		/* handle link change from link resetting */
1227 		__handle_link_change(dev);
1228 	}
1229 
1230 	if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
1231 		__handle_link_change(dev);
1232 
1233 	if (test_bit (EVENT_SET_RX_MODE, &dev->flags))
1234 		__handle_set_rx_mode(dev);
1235 
1236 
1237 	if (dev->flags)
1238 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1239 }
1240 
1241 /*-------------------------------------------------------------------------*/
1242 
1243 static void tx_complete (struct urb *urb)
1244 {
1245 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1246 	struct skb_data		*entry = (struct skb_data *) skb->cb;
1247 	struct usbnet		*dev = entry->dev;
1248 
1249 	if (urb->status == 0) {
1250 		struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->net->tstats);
1251 		unsigned long flags;
1252 
1253 		flags = u64_stats_update_begin_irqsave(&stats64->syncp);
1254 		u64_stats_add(&stats64->tx_packets, entry->packets);
1255 		u64_stats_add(&stats64->tx_bytes, entry->length);
1256 		u64_stats_update_end_irqrestore(&stats64->syncp, flags);
1257 	} else {
1258 		dev->net->stats.tx_errors++;
1259 
1260 		switch (urb->status) {
1261 		case -EPIPE:
1262 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1263 			break;
1264 
1265 		/* software-driven interface shutdown */
1266 		case -ECONNRESET:		// async unlink
1267 		case -ESHUTDOWN:		// hardware gone
1268 			break;
1269 
1270 		/* like rx, tx gets controller i/o faults during hub_wq
1271 		 * delays and so it uses the same throttling mechanism.
1272 		 */
1273 		case -EPROTO:
1274 		case -ETIME:
1275 		case -EILSEQ:
1276 			usb_mark_last_busy(dev->udev);
1277 			if (!timer_pending (&dev->delay)) {
1278 				mod_timer (&dev->delay,
1279 					jiffies + THROTTLE_JIFFIES);
1280 				netif_dbg(dev, link, dev->net,
1281 					  "tx throttle %d\n", urb->status);
1282 			}
1283 			netif_stop_queue (dev->net);
1284 			break;
1285 		default:
1286 			netif_dbg(dev, tx_err, dev->net,
1287 				  "tx err %d\n", entry->urb->status);
1288 			break;
1289 		}
1290 	}
1291 
1292 	usb_autopm_put_interface_async(dev->intf);
1293 	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1294 }
1295 
1296 /*-------------------------------------------------------------------------*/
1297 
1298 void usbnet_tx_timeout (struct net_device *net, unsigned int txqueue)
1299 {
1300 	struct usbnet		*dev = netdev_priv(net);
1301 
1302 	unlink_urbs (dev, &dev->txq);
1303 	tasklet_schedule (&dev->bh);
1304 	/* this needs to be handled individually because the generic layer
1305 	 * doesn't know what is sufficient and could not restore private
1306 	 * information if a remedy of an unconditional reset were used.
1307 	 */
1308 	if (dev->driver_info->recover)
1309 		(dev->driver_info->recover)(dev);
1310 }
1311 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1312 
1313 /*-------------------------------------------------------------------------*/
1314 
1315 static int build_dma_sg(const struct sk_buff *skb, struct urb *urb)
1316 {
1317 	unsigned num_sgs, total_len = 0;
1318 	int i, s = 0;
1319 
1320 	num_sgs = skb_shinfo(skb)->nr_frags + 1;
1321 	if (num_sgs == 1)
1322 		return 0;
1323 
1324 	/* reserve one for zero packet */
1325 	urb->sg = kmalloc_array(num_sgs + 1, sizeof(struct scatterlist),
1326 				GFP_ATOMIC);
1327 	if (!urb->sg)
1328 		return -ENOMEM;
1329 
1330 	urb->num_sgs = num_sgs;
1331 	sg_init_table(urb->sg, urb->num_sgs + 1);
1332 
1333 	sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb));
1334 	total_len += skb_headlen(skb);
1335 
1336 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1337 		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
1338 
1339 		total_len += skb_frag_size(f);
1340 		sg_set_page(&urb->sg[i + s], skb_frag_page(f), skb_frag_size(f),
1341 			    skb_frag_off(f));
1342 	}
1343 	urb->transfer_buffer_length = total_len;
1344 
1345 	return 1;
1346 }
1347 
1348 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1349 				     struct net_device *net)
1350 {
1351 	struct usbnet		*dev = netdev_priv(net);
1352 	unsigned int			length;
1353 	struct urb		*urb = NULL;
1354 	struct skb_data		*entry;
1355 	const struct driver_info *info = dev->driver_info;
1356 	unsigned long		flags;
1357 	int retval;
1358 
1359 	if (skb)
1360 		skb_tx_timestamp(skb);
1361 
1362 	// some devices want funky USB-level framing, for
1363 	// win32 driver (usually) and/or hardware quirks
1364 	if (info->tx_fixup) {
1365 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1366 		if (!skb) {
1367 			/* packet collected; minidriver waiting for more */
1368 			if (info->flags & FLAG_MULTI_PACKET)
1369 				goto not_drop;
1370 			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1371 			goto drop;
1372 		}
1373 	}
1374 
1375 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1376 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1377 		goto drop;
1378 	}
1379 
1380 	entry = (struct skb_data *) skb->cb;
1381 	entry->urb = urb;
1382 	entry->dev = dev;
1383 
1384 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1385 			skb->data, skb->len, tx_complete, skb);
1386 	if (dev->can_dma_sg) {
1387 		if (build_dma_sg(skb, urb) < 0)
1388 			goto drop;
1389 	}
1390 	length = urb->transfer_buffer_length;
1391 
1392 	/* don't assume the hardware handles USB_ZERO_PACKET
1393 	 * NOTE:  strictly conforming cdc-ether devices should expect
1394 	 * the ZLP here, but ignore the one-byte packet.
1395 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1396 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1397 	 * packet itself if needed.
1398 	 */
1399 	if (length % dev->maxpacket == 0) {
1400 		if (!(info->flags & FLAG_SEND_ZLP)) {
1401 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1402 				length++;
1403 				if (skb_tailroom(skb) && !urb->num_sgs) {
1404 					skb->data[skb->len] = 0;
1405 					__skb_put(skb, 1);
1406 				} else if (urb->num_sgs)
1407 					sg_set_buf(&urb->sg[urb->num_sgs++],
1408 							dev->padding_pkt, 1);
1409 			}
1410 		} else
1411 			urb->transfer_flags |= URB_ZERO_PACKET;
1412 	}
1413 	urb->transfer_buffer_length = length;
1414 
1415 	if (info->flags & FLAG_MULTI_PACKET) {
1416 		/* Driver has set number of packets and a length delta.
1417 		 * Calculate the complete length and ensure that it's
1418 		 * positive.
1419 		 */
1420 		entry->length += length;
1421 		if (WARN_ON_ONCE(entry->length <= 0))
1422 			entry->length = length;
1423 	} else {
1424 		usbnet_set_skb_tx_stats(skb, 1, length);
1425 	}
1426 
1427 	spin_lock_irqsave(&dev->txq.lock, flags);
1428 	retval = usb_autopm_get_interface_async(dev->intf);
1429 	if (retval < 0) {
1430 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1431 		goto drop;
1432 	}
1433 	if (netif_queue_stopped(net)) {
1434 		usb_autopm_put_interface_async(dev->intf);
1435 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1436 		goto drop;
1437 	}
1438 
1439 #ifdef CONFIG_PM
1440 	/* if this triggers the device is still a sleep */
1441 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1442 		/* transmission will be done in resume */
1443 		usb_anchor_urb(urb, &dev->deferred);
1444 		/* no use to process more packets */
1445 		netif_stop_queue(net);
1446 		usb_put_urb(urb);
1447 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1448 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1449 		goto deferred;
1450 	}
1451 #endif
1452 
1453 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1454 	case -EPIPE:
1455 		netif_stop_queue (net);
1456 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1457 		usb_autopm_put_interface_async(dev->intf);
1458 		break;
1459 	default:
1460 		usb_autopm_put_interface_async(dev->intf);
1461 		netif_dbg(dev, tx_err, dev->net,
1462 			  "tx: submit urb err %d\n", retval);
1463 		break;
1464 	case 0:
1465 		netif_trans_update(net);
1466 		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1467 		if (dev->txq.qlen >= TX_QLEN (dev))
1468 			netif_stop_queue (net);
1469 	}
1470 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1471 
1472 	if (retval) {
1473 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1474 drop:
1475 		dev->net->stats.tx_dropped++;
1476 not_drop:
1477 		if (skb)
1478 			dev_kfree_skb_any (skb);
1479 		if (urb) {
1480 			kfree(urb->sg);
1481 			usb_free_urb(urb);
1482 		}
1483 	} else
1484 		netif_dbg(dev, tx_queued, dev->net,
1485 			  "> tx, len %u, type 0x%x\n", length, skb->protocol);
1486 #ifdef CONFIG_PM
1487 deferred:
1488 #endif
1489 	return NETDEV_TX_OK;
1490 }
1491 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1492 
1493 static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1494 {
1495 	struct urb	*urb;
1496 	int		i;
1497 	int		ret = 0;
1498 
1499 	/* don't refill the queue all at once */
1500 	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1501 		urb = usb_alloc_urb(0, flags);
1502 		if (urb != NULL) {
1503 			ret = rx_submit(dev, urb, flags);
1504 			if (ret)
1505 				goto err;
1506 		} else {
1507 			ret = -ENOMEM;
1508 			goto err;
1509 		}
1510 	}
1511 err:
1512 	return ret;
1513 }
1514 
1515 static inline void usb_free_skb(struct sk_buff *skb)
1516 {
1517 	struct skb_data *entry = (struct skb_data *)skb->cb;
1518 
1519 	usb_free_urb(entry->urb);
1520 	dev_kfree_skb(skb);
1521 }
1522 
1523 /*-------------------------------------------------------------------------*/
1524 
1525 // tasklet (work deferred from completions, in_irq) or timer
1526 
1527 static void usbnet_bh (struct timer_list *t)
1528 {
1529 	struct usbnet		*dev = from_timer(dev, t, delay);
1530 	struct sk_buff		*skb;
1531 	struct skb_data		*entry;
1532 
1533 	while ((skb = skb_dequeue (&dev->done))) {
1534 		entry = (struct skb_data *) skb->cb;
1535 		switch (entry->state) {
1536 		case rx_done:
1537 			if (rx_process(dev, skb))
1538 				usb_free_skb(skb);
1539 			continue;
1540 		case tx_done:
1541 			kfree(entry->urb->sg);
1542 			fallthrough;
1543 		case rx_cleanup:
1544 			usb_free_skb(skb);
1545 			continue;
1546 		default:
1547 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1548 		}
1549 	}
1550 
1551 	/* restart RX again after disabling due to high error rate */
1552 	clear_bit(EVENT_RX_KILL, &dev->flags);
1553 
1554 	/* waiting for all pending urbs to complete?
1555 	 * only then can we forgo submitting anew
1556 	 */
1557 	if (waitqueue_active(&dev->wait)) {
1558 		if (dev->txq.qlen + dev->rxq.qlen + dev->done.qlen == 0)
1559 			wake_up_all(&dev->wait);
1560 
1561 	// or are we maybe short a few urbs?
1562 	} else if (netif_running (dev->net) &&
1563 		   netif_device_present (dev->net) &&
1564 		   netif_carrier_ok(dev->net) &&
1565 		   !timer_pending(&dev->delay) &&
1566 		   !test_bit(EVENT_RX_PAUSED, &dev->flags) &&
1567 		   !test_bit(EVENT_RX_HALT, &dev->flags)) {
1568 		int	temp = dev->rxq.qlen;
1569 
1570 		if (temp < RX_QLEN(dev)) {
1571 			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1572 				return;
1573 			if (temp != dev->rxq.qlen)
1574 				netif_dbg(dev, link, dev->net,
1575 					  "rxqlen %d --> %d\n",
1576 					  temp, dev->rxq.qlen);
1577 			if (dev->rxq.qlen < RX_QLEN(dev))
1578 				tasklet_schedule (&dev->bh);
1579 		}
1580 		if (dev->txq.qlen < TX_QLEN (dev))
1581 			netif_wake_queue (dev->net);
1582 	}
1583 }
1584 
1585 static void usbnet_bh_tasklet(struct tasklet_struct *t)
1586 {
1587 	struct usbnet *dev = from_tasklet(dev, t, bh);
1588 
1589 	usbnet_bh(&dev->delay);
1590 }
1591 
1592 
1593 /*-------------------------------------------------------------------------
1594  *
1595  * USB Device Driver support
1596  *
1597  *-------------------------------------------------------------------------*/
1598 
1599 // precondition: never called in_interrupt
1600 
1601 void usbnet_disconnect (struct usb_interface *intf)
1602 {
1603 	struct usbnet		*dev;
1604 	struct usb_device	*xdev;
1605 	struct net_device	*net;
1606 	struct urb		*urb;
1607 
1608 	dev = usb_get_intfdata(intf);
1609 	usb_set_intfdata(intf, NULL);
1610 	if (!dev)
1611 		return;
1612 
1613 	xdev = interface_to_usbdev (intf);
1614 
1615 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1616 		   intf->dev.driver->name,
1617 		   xdev->bus->bus_name, xdev->devpath,
1618 		   dev->driver_info->description);
1619 
1620 	net = dev->net;
1621 	unregister_netdev (net);
1622 
1623 	while ((urb = usb_get_from_anchor(&dev->deferred))) {
1624 		dev_kfree_skb(urb->context);
1625 		kfree(urb->sg);
1626 		usb_free_urb(urb);
1627 	}
1628 
1629 	if (dev->driver_info->unbind)
1630 		dev->driver_info->unbind(dev, intf);
1631 
1632 	usb_kill_urb(dev->interrupt);
1633 	usb_free_urb(dev->interrupt);
1634 	kfree(dev->padding_pkt);
1635 
1636 	free_netdev(net);
1637 }
1638 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1639 
1640 static const struct net_device_ops usbnet_netdev_ops = {
1641 	.ndo_open		= usbnet_open,
1642 	.ndo_stop		= usbnet_stop,
1643 	.ndo_start_xmit		= usbnet_start_xmit,
1644 	.ndo_tx_timeout		= usbnet_tx_timeout,
1645 	.ndo_set_rx_mode	= usbnet_set_rx_mode,
1646 	.ndo_change_mtu		= usbnet_change_mtu,
1647 	.ndo_set_mac_address 	= eth_mac_addr,
1648 	.ndo_validate_addr	= eth_validate_addr,
1649 };
1650 
1651 /*-------------------------------------------------------------------------*/
1652 
1653 // precondition: never called in_interrupt
1654 
1655 static const struct device_type wlan_type = {
1656 	.name	= "wlan",
1657 };
1658 
1659 static const struct device_type wwan_type = {
1660 	.name	= "wwan",
1661 };
1662 
1663 int
1664 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1665 {
1666 	struct usbnet			*dev;
1667 	struct net_device		*net;
1668 	struct usb_host_interface	*interface;
1669 	const struct driver_info	*info;
1670 	struct usb_device		*xdev;
1671 	int				status;
1672 	const char			*name;
1673 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1674 
1675 	/* usbnet already took usb runtime pm, so have to enable the feature
1676 	 * for usb interface, otherwise usb_autopm_get_interface may return
1677 	 * failure if RUNTIME_PM is enabled.
1678 	 */
1679 	if (!driver->supports_autosuspend) {
1680 		driver->supports_autosuspend = 1;
1681 		pm_runtime_enable(&udev->dev);
1682 	}
1683 
1684 	name = udev->dev.driver->name;
1685 	info = (const struct driver_info *) prod->driver_info;
1686 	if (!info) {
1687 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1688 		return -ENODEV;
1689 	}
1690 	xdev = interface_to_usbdev (udev);
1691 	interface = udev->cur_altsetting;
1692 
1693 	status = -ENOMEM;
1694 
1695 	// set up our own records
1696 	net = alloc_etherdev(sizeof(*dev));
1697 	if (!net)
1698 		goto out;
1699 
1700 	/* netdev_printk() needs this so do it as early as possible */
1701 	SET_NETDEV_DEV(net, &udev->dev);
1702 
1703 	dev = netdev_priv(net);
1704 	dev->udev = xdev;
1705 	dev->intf = udev;
1706 	dev->driver_info = info;
1707 	dev->driver_name = name;
1708 	dev->rx_speed = SPEED_UNSET;
1709 	dev->tx_speed = SPEED_UNSET;
1710 
1711 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1712 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1713 	init_waitqueue_head(&dev->wait);
1714 	skb_queue_head_init (&dev->rxq);
1715 	skb_queue_head_init (&dev->txq);
1716 	skb_queue_head_init (&dev->done);
1717 	skb_queue_head_init(&dev->rxq_pause);
1718 	tasklet_setup(&dev->bh, usbnet_bh_tasklet);
1719 	INIT_WORK (&dev->kevent, usbnet_deferred_kevent);
1720 	init_usb_anchor(&dev->deferred);
1721 	timer_setup(&dev->delay, usbnet_bh, 0);
1722 	mutex_init (&dev->phy_mutex);
1723 	mutex_init(&dev->interrupt_mutex);
1724 	dev->interrupt_count = 0;
1725 
1726 	dev->net = net;
1727 	strscpy(net->name, "usb%d", sizeof(net->name));
1728 	eth_hw_addr_set(net, node_id);
1729 
1730 	/* rx and tx sides can use different message sizes;
1731 	 * bind() should set rx_urb_size in that case.
1732 	 */
1733 	dev->hard_mtu = net->mtu + net->hard_header_len;
1734 	net->min_mtu = 0;
1735 	net->max_mtu = ETH_MAX_MTU;
1736 	net->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
1737 
1738 	net->netdev_ops = &usbnet_netdev_ops;
1739 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1740 	net->ethtool_ops = &usbnet_ethtool_ops;
1741 	net->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
1742 
1743 	// allow device-specific bind/init procedures
1744 	// NOTE net->name still not usable ...
1745 	if (info->bind) {
1746 		status = info->bind (dev, udev);
1747 		if (status < 0)
1748 			goto out1;
1749 
1750 		// heuristic:  "usb%d" for links we know are two-host,
1751 		// else "eth%d" when there's reasonable doubt.  userspace
1752 		// can rename the link if it knows better.
1753 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1754 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1755 		     (net->dev_addr [0] & 0x02) == 0))
1756 			strscpy(net->name, "eth%d", sizeof(net->name));
1757 		/* WLAN devices should always be named "wlan%d" */
1758 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1759 			strscpy(net->name, "wlan%d", sizeof(net->name));
1760 		/* WWAN devices should always be named "wwan%d" */
1761 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1762 			strscpy(net->name, "wwan%d", sizeof(net->name));
1763 
1764 		/* devices that cannot do ARP */
1765 		if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1766 			net->flags |= IFF_NOARP;
1767 
1768 		/* maybe the remote can't receive an Ethernet MTU */
1769 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1770 			net->mtu = dev->hard_mtu - net->hard_header_len;
1771 	} else if (!info->in || !info->out)
1772 		status = usbnet_get_endpoints (dev, udev);
1773 	else {
1774 		u8 ep_addrs[3] = {
1775 			info->in + USB_DIR_IN, info->out + USB_DIR_OUT, 0
1776 		};
1777 
1778 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1779 		dev->out = usb_sndbulkpipe (xdev, info->out);
1780 		if (!(info->flags & FLAG_NO_SETINT))
1781 			status = usb_set_interface (xdev,
1782 				interface->desc.bInterfaceNumber,
1783 				interface->desc.bAlternateSetting);
1784 		else
1785 			status = 0;
1786 
1787 		if (status == 0 && !usb_check_bulk_endpoints(udev, ep_addrs))
1788 			status = -EINVAL;
1789 	}
1790 	if (status >= 0 && dev->status)
1791 		status = init_status (dev, udev);
1792 	if (status < 0)
1793 		goto out3;
1794 
1795 	if (!dev->rx_urb_size)
1796 		dev->rx_urb_size = dev->hard_mtu;
1797 	dev->maxpacket = usb_maxpacket(dev->udev, dev->out);
1798 	if (dev->maxpacket == 0) {
1799 		/* that is a broken device */
1800 		status = -ENODEV;
1801 		goto out4;
1802 	}
1803 
1804 	/* let userspace know we have a random address */
1805 	if (ether_addr_equal(net->dev_addr, node_id))
1806 		net->addr_assign_type = NET_ADDR_RANDOM;
1807 
1808 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1809 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1810 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1811 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1812 
1813 	/* initialize max rx_qlen and tx_qlen */
1814 	usbnet_update_max_qlen(dev);
1815 
1816 	if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&
1817 		!(info->flags & FLAG_MULTI_PACKET)) {
1818 		dev->padding_pkt = kzalloc(1, GFP_KERNEL);
1819 		if (!dev->padding_pkt) {
1820 			status = -ENOMEM;
1821 			goto out4;
1822 		}
1823 	}
1824 
1825 	status = register_netdev (net);
1826 	if (status)
1827 		goto out5;
1828 	netif_info(dev, probe, dev->net,
1829 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1830 		   udev->dev.driver->name,
1831 		   xdev->bus->bus_name, xdev->devpath,
1832 		   dev->driver_info->description,
1833 		   net->dev_addr);
1834 
1835 	// ok, it's ready to go.
1836 	usb_set_intfdata (udev, dev);
1837 
1838 	netif_device_attach (net);
1839 
1840 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1841 		usbnet_link_change(dev, 0, 0);
1842 
1843 	return 0;
1844 
1845 out5:
1846 	kfree(dev->padding_pkt);
1847 out4:
1848 	usb_free_urb(dev->interrupt);
1849 out3:
1850 	if (info->unbind)
1851 		info->unbind (dev, udev);
1852 out1:
1853 	/* subdrivers must undo all they did in bind() if they
1854 	 * fail it, but we may fail later and a deferred kevent
1855 	 * may trigger an error resubmitting itself and, worse,
1856 	 * schedule a timer. So we kill it all just in case.
1857 	 */
1858 	cancel_work_sync(&dev->kevent);
1859 	del_timer_sync(&dev->delay);
1860 	free_netdev(net);
1861 out:
1862 	return status;
1863 }
1864 EXPORT_SYMBOL_GPL(usbnet_probe);
1865 
1866 /*-------------------------------------------------------------------------*/
1867 
1868 /*
1869  * suspend the whole driver as soon as the first interface is suspended
1870  * resume only when the last interface is resumed
1871  */
1872 
1873 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1874 {
1875 	struct usbnet		*dev = usb_get_intfdata(intf);
1876 
1877 	if (!dev->suspend_count++) {
1878 		spin_lock_irq(&dev->txq.lock);
1879 		/* don't autosuspend while transmitting */
1880 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1881 			dev->suspend_count--;
1882 			spin_unlock_irq(&dev->txq.lock);
1883 			return -EBUSY;
1884 		} else {
1885 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1886 			spin_unlock_irq(&dev->txq.lock);
1887 		}
1888 		/*
1889 		 * accelerate emptying of the rx and queues, to avoid
1890 		 * having everything error out.
1891 		 */
1892 		netif_device_detach (dev->net);
1893 		usbnet_terminate_urbs(dev);
1894 		__usbnet_status_stop_force(dev);
1895 
1896 		/*
1897 		 * reattach so runtime management can use and
1898 		 * wake the device
1899 		 */
1900 		netif_device_attach (dev->net);
1901 	}
1902 	return 0;
1903 }
1904 EXPORT_SYMBOL_GPL(usbnet_suspend);
1905 
1906 int usbnet_resume (struct usb_interface *intf)
1907 {
1908 	struct usbnet		*dev = usb_get_intfdata(intf);
1909 	struct sk_buff          *skb;
1910 	struct urb              *res;
1911 	int                     retval;
1912 
1913 	if (!--dev->suspend_count) {
1914 		/* resume interrupt URB if it was previously submitted */
1915 		__usbnet_status_start_force(dev, GFP_NOIO);
1916 
1917 		spin_lock_irq(&dev->txq.lock);
1918 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1919 
1920 			skb = (struct sk_buff *)res->context;
1921 			retval = usb_submit_urb(res, GFP_ATOMIC);
1922 			if (retval < 0) {
1923 				dev_kfree_skb_any(skb);
1924 				kfree(res->sg);
1925 				usb_free_urb(res);
1926 				usb_autopm_put_interface_async(dev->intf);
1927 			} else {
1928 				netif_trans_update(dev->net);
1929 				__skb_queue_tail(&dev->txq, skb);
1930 			}
1931 		}
1932 
1933 		smp_mb();
1934 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1935 		spin_unlock_irq(&dev->txq.lock);
1936 
1937 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1938 			/* handle remote wakeup ASAP
1939 			 * we cannot race against stop
1940 			 */
1941 			if (netif_device_present(dev->net) &&
1942 				!timer_pending(&dev->delay) &&
1943 				!test_bit(EVENT_RX_HALT, &dev->flags))
1944 					rx_alloc_submit(dev, GFP_NOIO);
1945 
1946 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1947 				netif_tx_wake_all_queues(dev->net);
1948 			tasklet_schedule (&dev->bh);
1949 		}
1950 	}
1951 
1952 	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1953 		usb_autopm_get_interface_no_resume(intf);
1954 
1955 	return 0;
1956 }
1957 EXPORT_SYMBOL_GPL(usbnet_resume);
1958 
1959 /*
1960  * Either a subdriver implements manage_power, then it is assumed to always
1961  * be ready to be suspended or it reports the readiness to be suspended
1962  * explicitly
1963  */
1964 void usbnet_device_suggests_idle(struct usbnet *dev)
1965 {
1966 	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1967 		dev->intf->needs_remote_wakeup = 1;
1968 		usb_autopm_put_interface_async(dev->intf);
1969 	}
1970 }
1971 EXPORT_SYMBOL(usbnet_device_suggests_idle);
1972 
1973 /*
1974  * For devices that can do without special commands
1975  */
1976 int usbnet_manage_power(struct usbnet *dev, int on)
1977 {
1978 	dev->intf->needs_remote_wakeup = on;
1979 	return 0;
1980 }
1981 EXPORT_SYMBOL(usbnet_manage_power);
1982 
1983 void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
1984 {
1985 	/* update link after link is reseted */
1986 	if (link && !need_reset)
1987 		netif_carrier_on(dev->net);
1988 	else
1989 		netif_carrier_off(dev->net);
1990 
1991 	if (need_reset && link)
1992 		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
1993 	else
1994 		usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
1995 }
1996 EXPORT_SYMBOL(usbnet_link_change);
1997 
1998 /*-------------------------------------------------------------------------*/
1999 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2000 			     u16 value, u16 index, void *data, u16 size)
2001 {
2002 	void *buf = NULL;
2003 	int err = -ENOMEM;
2004 
2005 	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
2006 		   " value=0x%04x index=0x%04x size=%d\n",
2007 		   cmd, reqtype, value, index, size);
2008 
2009 	if (size) {
2010 		buf = kmalloc(size, GFP_NOIO);
2011 		if (!buf)
2012 			goto out;
2013 	}
2014 
2015 	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
2016 			      cmd, reqtype, value, index, buf, size,
2017 			      USB_CTRL_GET_TIMEOUT);
2018 	if (err > 0 && err <= size) {
2019 		if (data)
2020 			memcpy(data, buf, err);
2021 		else
2022 			netdev_dbg(dev->net,
2023 				   "Huh? Data requested but thrown away.\n");
2024 	}
2025 	kfree(buf);
2026 out:
2027 	return err;
2028 }
2029 
2030 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2031 			      u16 value, u16 index, const void *data,
2032 			      u16 size)
2033 {
2034 	void *buf = NULL;
2035 	int err = -ENOMEM;
2036 
2037 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2038 		   " value=0x%04x index=0x%04x size=%d\n",
2039 		   cmd, reqtype, value, index, size);
2040 
2041 	if (data) {
2042 		buf = kmemdup(data, size, GFP_NOIO);
2043 		if (!buf)
2044 			goto out;
2045 	} else {
2046         if (size) {
2047             WARN_ON_ONCE(1);
2048             err = -EINVAL;
2049             goto out;
2050         }
2051     }
2052 
2053 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
2054 			      cmd, reqtype, value, index, buf, size,
2055 			      USB_CTRL_SET_TIMEOUT);
2056 	kfree(buf);
2057 
2058 out:
2059 	return err;
2060 }
2061 
2062 /*
2063  * The function can't be called inside suspend/resume callback,
2064  * otherwise deadlock will be caused.
2065  */
2066 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2067 		    u16 value, u16 index, void *data, u16 size)
2068 {
2069 	int ret;
2070 
2071 	if (usb_autopm_get_interface(dev->intf) < 0)
2072 		return -ENODEV;
2073 	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2074 				data, size);
2075 	usb_autopm_put_interface(dev->intf);
2076 	return ret;
2077 }
2078 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
2079 
2080 /*
2081  * The function can't be called inside suspend/resume callback,
2082  * otherwise deadlock will be caused.
2083  */
2084 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2085 		     u16 value, u16 index, const void *data, u16 size)
2086 {
2087 	int ret;
2088 
2089 	if (usb_autopm_get_interface(dev->intf) < 0)
2090 		return -ENODEV;
2091 	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2092 				 data, size);
2093 	usb_autopm_put_interface(dev->intf);
2094 	return ret;
2095 }
2096 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
2097 
2098 /*
2099  * The function can be called inside suspend/resume callback safely
2100  * and should only be called by suspend/resume callback generally.
2101  */
2102 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2103 			  u16 value, u16 index, void *data, u16 size)
2104 {
2105 	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2106 				 data, size);
2107 }
2108 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
2109 
2110 /*
2111  * The function can be called inside suspend/resume callback safely
2112  * and should only be called by suspend/resume callback generally.
2113  */
2114 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2115 			  u16 value, u16 index, const void *data,
2116 			  u16 size)
2117 {
2118 	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2119 				  data, size);
2120 }
2121 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
2122 
2123 static void usbnet_async_cmd_cb(struct urb *urb)
2124 {
2125 	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
2126 	int status = urb->status;
2127 
2128 	if (status < 0)
2129 		dev_dbg(&urb->dev->dev, "%s failed with %d",
2130 			__func__, status);
2131 
2132 	kfree(req);
2133 	usb_free_urb(urb);
2134 }
2135 
2136 /*
2137  * The caller must make sure that device can't be put into suspend
2138  * state until the control URB completes.
2139  */
2140 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
2141 			   u16 value, u16 index, const void *data, u16 size)
2142 {
2143 	struct usb_ctrlrequest *req;
2144 	struct urb *urb;
2145 	int err = -ENOMEM;
2146 	void *buf = NULL;
2147 
2148 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2149 		   " value=0x%04x index=0x%04x size=%d\n",
2150 		   cmd, reqtype, value, index, size);
2151 
2152 	urb = usb_alloc_urb(0, GFP_ATOMIC);
2153 	if (!urb)
2154 		goto fail;
2155 
2156 	if (data) {
2157 		buf = kmemdup(data, size, GFP_ATOMIC);
2158 		if (!buf) {
2159 			netdev_err(dev->net, "Error allocating buffer"
2160 				   " in %s!\n", __func__);
2161 			goto fail_free_urb;
2162 		}
2163 	}
2164 
2165 	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
2166 	if (!req)
2167 		goto fail_free_buf;
2168 
2169 	req->bRequestType = reqtype;
2170 	req->bRequest = cmd;
2171 	req->wValue = cpu_to_le16(value);
2172 	req->wIndex = cpu_to_le16(index);
2173 	req->wLength = cpu_to_le16(size);
2174 
2175 	usb_fill_control_urb(urb, dev->udev,
2176 			     usb_sndctrlpipe(dev->udev, 0),
2177 			     (void *)req, buf, size,
2178 			     usbnet_async_cmd_cb, req);
2179 	urb->transfer_flags |= URB_FREE_BUFFER;
2180 
2181 	err = usb_submit_urb(urb, GFP_ATOMIC);
2182 	if (err < 0) {
2183 		netdev_err(dev->net, "Error submitting the control"
2184 			   " message: status=%d\n", err);
2185 		goto fail_free_all;
2186 	}
2187 	return 0;
2188 
2189 fail_free_all:
2190 	kfree(req);
2191 fail_free_buf:
2192 	kfree(buf);
2193 	/*
2194 	 * avoid a double free
2195 	 * needed because the flag can be set only
2196 	 * after filling the URB
2197 	 */
2198 	urb->transfer_flags = 0;
2199 fail_free_urb:
2200 	usb_free_urb(urb);
2201 fail:
2202 	return err;
2203 
2204 }
2205 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
2206 /*-------------------------------------------------------------------------*/
2207 
2208 static int __init usbnet_init(void)
2209 {
2210 	/* Compiler should optimize this out. */
2211 	BUILD_BUG_ON(
2212 		sizeof_field(struct sk_buff, cb) < sizeof(struct skb_data));
2213 
2214 	eth_random_addr(node_id);
2215 	return 0;
2216 }
2217 module_init(usbnet_init);
2218 
2219 static void __exit usbnet_exit(void)
2220 {
2221 }
2222 module_exit(usbnet_exit);
2223 
2224 MODULE_AUTHOR("David Brownell");
2225 MODULE_DESCRIPTION("USB network driver framework");
2226 MODULE_LICENSE("GPL");
2227