xref: /linux/drivers/net/usb/usbnet.c (revision 634ec1fc7982efeeeeed4a7688b0004827b43a21)
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 /* use ethtool to change the level for any given device */
65 static int msg_level = -1;
66 module_param (msg_level, int, 0);
67 MODULE_PARM_DESC (msg_level, "Override default message level");
68 
69 /*-------------------------------------------------------------------------*/
70 
71 static const char * const usbnet_event_names[] = {
72 	[EVENT_TX_HALT]		   = "EVENT_TX_HALT",
73 	[EVENT_RX_HALT]		   = "EVENT_RX_HALT",
74 	[EVENT_RX_MEMORY]	   = "EVENT_RX_MEMORY",
75 	[EVENT_STS_SPLIT]	   = "EVENT_STS_SPLIT",
76 	[EVENT_LINK_RESET]	   = "EVENT_LINK_RESET",
77 	[EVENT_RX_PAUSED]	   = "EVENT_RX_PAUSED",
78 	[EVENT_DEV_ASLEEP]	   = "EVENT_DEV_ASLEEP",
79 	[EVENT_DEV_OPEN]	   = "EVENT_DEV_OPEN",
80 	[EVENT_DEVICE_REPORT_IDLE] = "EVENT_DEVICE_REPORT_IDLE",
81 	[EVENT_NO_RUNTIME_PM]	   = "EVENT_NO_RUNTIME_PM",
82 	[EVENT_RX_KILL]		   = "EVENT_RX_KILL",
83 	[EVENT_LINK_CHANGE]	   = "EVENT_LINK_CHANGE",
84 	[EVENT_SET_RX_MODE]	   = "EVENT_SET_RX_MODE",
85 	[EVENT_NO_IP_ALIGN]	   = "EVENT_NO_IP_ALIGN",
86 };
87 
88 /* handles CDC Ethernet and many other network "bulk data" interfaces */
usbnet_get_endpoints(struct usbnet * dev,struct usb_interface * intf)89 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
90 {
91 	int				tmp;
92 	struct usb_host_interface	*alt = NULL;
93 	struct usb_host_endpoint	*in = NULL, *out = NULL;
94 	struct usb_host_endpoint	*status = NULL;
95 
96 	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
97 		unsigned	ep;
98 
99 		in = out = status = NULL;
100 		alt = intf->altsetting + tmp;
101 
102 		/* take the first altsetting with in-bulk + out-bulk;
103 		 * remember any status endpoint, just in case;
104 		 * ignore other endpoints and altsettings.
105 		 */
106 		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
107 			struct usb_host_endpoint	*e;
108 			int				intr = 0;
109 
110 			e = alt->endpoint + ep;
111 
112 			/* ignore endpoints which cannot transfer data */
113 			if (!usb_endpoint_maxp(&e->desc))
114 				continue;
115 
116 			switch (e->desc.bmAttributes) {
117 			case USB_ENDPOINT_XFER_INT:
118 				if (!usb_endpoint_dir_in(&e->desc))
119 					continue;
120 				intr = 1;
121 				fallthrough;
122 			case USB_ENDPOINT_XFER_BULK:
123 				break;
124 			default:
125 				continue;
126 			}
127 			if (usb_endpoint_dir_in(&e->desc)) {
128 				if (!intr && !in)
129 					in = e;
130 				else if (intr && !status)
131 					status = e;
132 			} else {
133 				if (!out)
134 					out = e;
135 			}
136 		}
137 		if (in && out)
138 			break;
139 	}
140 	if (!alt || !in || !out)
141 		return -EINVAL;
142 
143 	if (alt->desc.bAlternateSetting != 0 ||
144 	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
145 		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
146 				alt->desc.bAlternateSetting);
147 		if (tmp < 0)
148 			return tmp;
149 	}
150 
151 	dev->in = usb_rcvbulkpipe (dev->udev,
152 			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
153 	dev->out = usb_sndbulkpipe (dev->udev,
154 			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
155 	dev->status = status;
156 	return 0;
157 }
158 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
159 
usbnet_get_ethernet_addr(struct usbnet * dev,int iMACAddress)160 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
161 {
162 	u8		addr[ETH_ALEN];
163 	int 		tmp = -1, ret;
164 	unsigned char	buf [13];
165 
166 	ret = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
167 	if (ret == 12)
168 		tmp = hex2bin(addr, buf, 6);
169 	if (tmp < 0) {
170 		dev_dbg(&dev->udev->dev,
171 			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
172 		if (ret >= 0)
173 			ret = -EINVAL;
174 		return ret;
175 	}
176 	eth_hw_addr_set(dev->net, addr);
177 	return 0;
178 }
179 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
180 
usbnet_needs_usb_name_format(struct usbnet * dev,struct net_device * net)181 static bool usbnet_needs_usb_name_format(struct usbnet *dev, struct net_device *net)
182 {
183 	/* Point to point devices which don't have a real MAC address
184 	 * (or report a fake local one) have historically used the usb%d
185 	 * naming. Preserve this..
186 	 */
187 	return (dev->driver_info->flags & FLAG_POINTTOPOINT) != 0 &&
188 		(is_zero_ether_addr(net->dev_addr) ||
189 		 is_local_ether_addr(net->dev_addr));
190 }
191 
intr_complete(struct urb * urb)192 static void intr_complete (struct urb *urb)
193 {
194 	struct usbnet	*dev = urb->context;
195 	int		status = urb->status;
196 
197 	switch (status) {
198 	/* success */
199 	case 0:
200 		dev->driver_info->status(dev, urb);
201 		break;
202 
203 	/* software-driven interface shutdown */
204 	case -ENOENT:		/* urb killed */
205 	case -ESHUTDOWN:	/* hardware gone */
206 		netif_dbg(dev, ifdown, dev->net,
207 			  "intr shutdown, code %d\n", status);
208 		return;
209 
210 	/* NOTE:  not throttling like RX/TX, since this endpoint
211 	 * already polls infrequently
212 	 */
213 	default:
214 		netdev_dbg(dev->net, "intr status %d\n", status);
215 		break;
216 	}
217 
218 	status = usb_submit_urb (urb, GFP_ATOMIC);
219 	if (status != 0)
220 		netif_err(dev, timer, dev->net,
221 			  "intr resubmit --> %d\n", status);
222 }
223 
init_status(struct usbnet * dev,struct usb_interface * intf)224 static int init_status (struct usbnet *dev, struct usb_interface *intf)
225 {
226 	char		*buf = NULL;
227 	unsigned	pipe = 0;
228 	unsigned	maxp;
229 	unsigned	period;
230 
231 	if (!dev->driver_info->status)
232 		return 0;
233 
234 	pipe = usb_rcvintpipe (dev->udev,
235 			dev->status->desc.bEndpointAddress
236 				& USB_ENDPOINT_NUMBER_MASK);
237 	maxp = usb_maxpacket(dev->udev, pipe);
238 
239 	/* avoid 1 msec chatter:  min 8 msec poll rate */
240 	period = max ((int) dev->status->desc.bInterval,
241 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
242 
243 	buf = kmalloc (maxp, GFP_KERNEL);
244 	if (buf) {
245 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
246 		if (!dev->interrupt) {
247 			kfree (buf);
248 			return -ENOMEM;
249 		} else {
250 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
251 				buf, maxp, intr_complete, dev, period);
252 			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
253 			dev_dbg(&intf->dev,
254 				"status ep%din, %d bytes period %d\n",
255 				usb_pipeendpoint(pipe), maxp, period);
256 		}
257 	}
258 	return 0;
259 }
260 
261 /* Submit the interrupt URB if not previously submitted, increasing refcount */
usbnet_status_start(struct usbnet * dev,gfp_t mem_flags)262 int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
263 {
264 	int ret = 0;
265 
266 	WARN_ON_ONCE(dev->interrupt == NULL);
267 	if (dev->interrupt) {
268 		mutex_lock(&dev->interrupt_mutex);
269 
270 		if (++dev->interrupt_count == 1)
271 			ret = usb_submit_urb(dev->interrupt, mem_flags);
272 
273 		dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
274 			dev->interrupt_count);
275 		mutex_unlock(&dev->interrupt_mutex);
276 	}
277 	return ret;
278 }
279 EXPORT_SYMBOL_GPL(usbnet_status_start);
280 
281 /* For resume; submit interrupt URB if previously submitted */
__usbnet_status_start_force(struct usbnet * dev,gfp_t mem_flags)282 static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
283 {
284 	int ret = 0;
285 
286 	mutex_lock(&dev->interrupt_mutex);
287 	if (dev->interrupt_count) {
288 		ret = usb_submit_urb(dev->interrupt, mem_flags);
289 		dev_dbg(&dev->udev->dev,
290 			"submitted interrupt URB for resume\n");
291 	}
292 	mutex_unlock(&dev->interrupt_mutex);
293 	return ret;
294 }
295 
296 /* Kill the interrupt URB if all submitters want it killed */
usbnet_status_stop(struct usbnet * dev)297 void usbnet_status_stop(struct usbnet *dev)
298 {
299 	if (dev->interrupt) {
300 		mutex_lock(&dev->interrupt_mutex);
301 		WARN_ON(dev->interrupt_count == 0);
302 
303 		if (dev->interrupt_count && --dev->interrupt_count == 0)
304 			usb_kill_urb(dev->interrupt);
305 
306 		dev_dbg(&dev->udev->dev,
307 			"decremented interrupt URB count to %d\n",
308 			dev->interrupt_count);
309 		mutex_unlock(&dev->interrupt_mutex);
310 	}
311 }
312 EXPORT_SYMBOL_GPL(usbnet_status_stop);
313 
314 /* For suspend; always kill interrupt URB */
__usbnet_status_stop_force(struct usbnet * dev)315 static void __usbnet_status_stop_force(struct usbnet *dev)
316 {
317 	if (dev->interrupt) {
318 		mutex_lock(&dev->interrupt_mutex);
319 		usb_kill_urb(dev->interrupt);
320 		dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
321 		mutex_unlock(&dev->interrupt_mutex);
322 	}
323 }
324 
325 /* Passes this packet up the stack, updating its accounting.
326  * Some link protocols batch packets, so their rx_fixup paths
327  * can return clones as well as just modify the original skb.
328  */
usbnet_skb_return(struct usbnet * dev,struct sk_buff * skb)329 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
330 {
331 	struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->net->tstats);
332 	unsigned long flags;
333 	int	status;
334 
335 	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
336 		skb_queue_tail(&dev->rxq_pause, skb);
337 		return;
338 	}
339 
340 	/* only update if unset to allow minidriver rx_fixup override */
341 	if (skb->protocol == 0)
342 		skb->protocol = eth_type_trans (skb, dev->net);
343 
344 	flags = u64_stats_update_begin_irqsave(&stats64->syncp);
345 	u64_stats_inc(&stats64->rx_packets);
346 	u64_stats_add(&stats64->rx_bytes, skb->len);
347 	u64_stats_update_end_irqrestore(&stats64->syncp, flags);
348 
349 	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
350 		  skb->len + sizeof (struct ethhdr), skb->protocol);
351 	memset (skb->cb, 0, sizeof (struct skb_data));
352 
353 	if (skb_defer_rx_timestamp(skb))
354 		return;
355 
356 	status = netif_rx (skb);
357 	if (status != NET_RX_SUCCESS)
358 		netif_dbg(dev, rx_err, dev->net,
359 			  "netif_rx status %d\n", status);
360 }
361 EXPORT_SYMBOL_GPL(usbnet_skb_return);
362 
363 /* must be called if hard_mtu or rx_urb_size changed */
usbnet_update_max_qlen(struct usbnet * dev)364 void usbnet_update_max_qlen(struct usbnet *dev)
365 {
366 	enum usb_device_speed speed = dev->udev->speed;
367 
368 	if (!dev->rx_urb_size || !dev->hard_mtu)
369 		goto insanity;
370 	switch (speed) {
371 	case USB_SPEED_HIGH:
372 		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
373 		dev->tx_qlen = MAX_QUEUE_MEMORY / dev->hard_mtu;
374 		break;
375 	case USB_SPEED_SUPER:
376 	case USB_SPEED_SUPER_PLUS:
377 		/*
378 		 * Not take default 5ms qlen for super speed HC to
379 		 * save memory, and iperf tests show 2.5ms qlen can
380 		 * work well
381 		 */
382 		dev->rx_qlen = 5 * MAX_QUEUE_MEMORY / dev->rx_urb_size;
383 		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
384 		break;
385 	default:
386 insanity:
387 		dev->rx_qlen = dev->tx_qlen = 4;
388 	}
389 }
390 EXPORT_SYMBOL_GPL(usbnet_update_max_qlen);
391 
392 
393 /*-------------------------------------------------------------------------
394  *
395  * Network Device Driver (peer link to "Host Device", from USB host)
396  *
397  *-------------------------------------------------------------------------*/
398 
usbnet_change_mtu(struct net_device * net,int new_mtu)399 int usbnet_change_mtu (struct net_device *net, int new_mtu)
400 {
401 	struct usbnet	*dev = netdev_priv(net);
402 	int		ll_mtu = new_mtu + net->hard_header_len;
403 	int		old_hard_mtu = dev->hard_mtu;
404 	int		old_rx_urb_size = dev->rx_urb_size;
405 
406 	// no second zero-length packet read wanted after mtu-sized packets
407 	if ((ll_mtu % dev->maxpacket) == 0)
408 		return -EDOM;
409 	WRITE_ONCE(net->mtu, new_mtu);
410 
411 	dev->hard_mtu = net->mtu + net->hard_header_len;
412 	if (dev->rx_urb_size == old_hard_mtu) {
413 		dev->rx_urb_size = dev->hard_mtu;
414 		if (dev->rx_urb_size > old_rx_urb_size) {
415 			usbnet_pause_rx(dev);
416 			usbnet_unlink_rx_urbs(dev);
417 			usbnet_resume_rx(dev);
418 		}
419 	}
420 
421 	/* max qlen depend on hard_mtu and rx_urb_size */
422 	usbnet_update_max_qlen(dev);
423 
424 	return 0;
425 }
426 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
427 
428 /* The caller must hold list->lock */
__usbnet_queue_skb(struct sk_buff_head * list,struct sk_buff * newsk,enum skb_state state)429 static void __usbnet_queue_skb(struct sk_buff_head *list,
430 			struct sk_buff *newsk, enum skb_state state)
431 {
432 	struct skb_data *entry = (struct skb_data *) newsk->cb;
433 
434 	__skb_queue_tail(list, newsk);
435 	entry->state = state;
436 }
437 
438 /*-------------------------------------------------------------------------*/
439 
440 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
441  * completion callbacks.  2.5 should have fixed those bugs...
442  */
443 
defer_bh(struct usbnet * dev,struct sk_buff * skb,struct sk_buff_head * list,enum skb_state state)444 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
445 		struct sk_buff_head *list, enum skb_state state)
446 {
447 	unsigned long		flags;
448 	enum skb_state 		old_state;
449 	struct skb_data *entry = (struct skb_data *) skb->cb;
450 
451 	spin_lock_irqsave(&list->lock, flags);
452 	old_state = entry->state;
453 	entry->state = state;
454 	__skb_unlink(skb, list);
455 
456 	/* defer_bh() is never called with list == &dev->done.
457 	 * spin_lock_nested() tells lockdep that it is OK to take
458 	 * dev->done.lock here with list->lock held.
459 	 */
460 	spin_lock_nested(&dev->done.lock, SINGLE_DEPTH_NESTING);
461 
462 	__skb_queue_tail(&dev->done, skb);
463 	if (dev->done.qlen == 1)
464 		queue_work(system_bh_wq, &dev->bh_work);
465 	spin_unlock(&dev->done.lock);
466 	spin_unlock_irqrestore(&list->lock, flags);
467 	return old_state;
468 }
469 
470 /* some work can't be done in tasklets, so we use keventd
471  *
472  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
473  * but tasklet_schedule() doesn't.  hope the failure is rare.
474  */
usbnet_defer_kevent(struct usbnet * dev,int work)475 void usbnet_defer_kevent (struct usbnet *dev, int work)
476 {
477 	set_bit (work, &dev->flags);
478 	if (!usbnet_going_away(dev)) {
479 		if (!schedule_work(&dev->kevent))
480 			netdev_dbg(dev->net,
481 				   "kevent %s may have been dropped\n",
482 				   usbnet_event_names[work]);
483 		else
484 			netdev_dbg(dev->net,
485 				   "kevent %s scheduled\n", usbnet_event_names[work]);
486 	}
487 }
488 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
489 
490 /*-------------------------------------------------------------------------*/
491 
492 static void rx_complete (struct urb *urb);
493 
rx_submit(struct usbnet * dev,struct urb * urb,gfp_t flags)494 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
495 {
496 	struct sk_buff		*skb;
497 	struct skb_data		*entry;
498 	int			retval = 0;
499 	unsigned long		lockflags;
500 	size_t			size = dev->rx_urb_size;
501 
502 	/* prevent rx skb allocation when error ratio is high */
503 	if (test_bit(EVENT_RX_KILL, &dev->flags)) {
504 		usb_free_urb(urb);
505 		return -ENOLINK;
506 	}
507 
508 	if (test_bit(EVENT_NO_IP_ALIGN, &dev->flags))
509 		skb = __netdev_alloc_skb(dev->net, size, flags);
510 	else
511 		skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
512 	if (!skb) {
513 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
514 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
515 		usb_free_urb (urb);
516 		return -ENOMEM;
517 	}
518 
519 	entry = (struct skb_data *) skb->cb;
520 	entry->urb = urb;
521 	entry->dev = dev;
522 	entry->length = 0;
523 
524 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
525 		skb->data, size, rx_complete, skb);
526 
527 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
528 
529 	if (netif_running (dev->net) &&
530 	    netif_device_present (dev->net) &&
531 	    test_bit(EVENT_DEV_OPEN, &dev->flags) &&
532 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
533 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags) &&
534 	    !usbnet_going_away(dev)) {
535 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
536 		case -EPIPE:
537 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
538 			break;
539 		case -ENOMEM:
540 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
541 			break;
542 		case -ENODEV:
543 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
544 			netif_device_detach (dev->net);
545 			break;
546 		case -EHOSTUNREACH:
547 			retval = -ENOLINK;
548 			break;
549 		default:
550 			netif_dbg(dev, rx_err, dev->net,
551 				  "rx submit, %d\n", retval);
552 			queue_work(system_bh_wq, &dev->bh_work);
553 			break;
554 		case 0:
555 			__usbnet_queue_skb(&dev->rxq, skb, rx_start);
556 		}
557 	} else {
558 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
559 		retval = -ENOLINK;
560 	}
561 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
562 	if (retval) {
563 		dev_kfree_skb_any (skb);
564 		usb_free_urb (urb);
565 	}
566 	return retval;
567 }
568 
569 
570 /*-------------------------------------------------------------------------*/
571 
rx_process(struct usbnet * dev,struct sk_buff * skb)572 static inline int rx_process(struct usbnet *dev, struct sk_buff *skb)
573 {
574 	if (dev->driver_info->rx_fixup &&
575 	    !dev->driver_info->rx_fixup (dev, skb)) {
576 		/* With RX_ASSEMBLE, rx_fixup() must update counters */
577 		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
578 			dev->net->stats.rx_errors++;
579 		return -EPROTO;
580 	}
581 	// else network stack removes extra byte if we forced a short packet
582 
583 	/* all data was already cloned from skb inside the driver */
584 	if (dev->driver_info->flags & FLAG_MULTI_PACKET)
585 		return -EALREADY;
586 
587 	if (skb->len < ETH_HLEN) {
588 		dev->net->stats.rx_errors++;
589 		dev->net->stats.rx_length_errors++;
590 		netif_dbg(dev, rx_err, dev->net, "rx length %d\n", skb->len);
591 		return -EPROTO;
592 	}
593 
594 	usbnet_skb_return(dev, skb);
595 	return 0;
596 }
597 
598 /*-------------------------------------------------------------------------*/
599 
rx_complete(struct urb * urb)600 static void rx_complete (struct urb *urb)
601 {
602 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
603 	struct skb_data		*entry = (struct skb_data *) skb->cb;
604 	struct usbnet		*dev = entry->dev;
605 	int			urb_status = urb->status;
606 	enum skb_state		state;
607 
608 	skb_put (skb, urb->actual_length);
609 	state = rx_done;
610 	entry->urb = NULL;
611 
612 	switch (urb_status) {
613 	/* success */
614 	case 0:
615 		break;
616 
617 	/* stalls need manual reset. this is rare ... except that
618 	 * when going through USB 2.0 TTs, unplug appears this way.
619 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
620 	 * storm, recovering as needed.
621 	 */
622 	case -EPIPE:
623 		dev->net->stats.rx_errors++;
624 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
625 		fallthrough;
626 
627 	/* software-driven interface shutdown */
628 	case -ECONNRESET:		/* async unlink */
629 	case -ESHUTDOWN:		/* hardware gone */
630 		netif_dbg(dev, ifdown, dev->net,
631 			  "rx shutdown, code %d\n", urb_status);
632 		goto block;
633 
634 	/* we get controller i/o faults during hub_wq disconnect() delays.
635 	 * throttle down resubmits, to avoid log floods; just temporarily,
636 	 * so we still recover when the fault isn't a hub_wq delay.
637 	 */
638 	case -EPROTO:
639 	case -ETIME:
640 	case -EILSEQ:
641 		dev->net->stats.rx_errors++;
642 		if (!timer_pending (&dev->delay)) {
643 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
644 			netif_dbg(dev, link, dev->net,
645 				  "rx throttle %d\n", urb_status);
646 		}
647 block:
648 		state = rx_cleanup;
649 		entry->urb = urb;
650 		urb = NULL;
651 		break;
652 
653 	/* data overrun ... flush fifo? */
654 	case -EOVERFLOW:
655 		dev->net->stats.rx_over_errors++;
656 		fallthrough;
657 
658 	default:
659 		state = rx_cleanup;
660 		dev->net->stats.rx_errors++;
661 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
662 		break;
663 	}
664 
665 	/* stop rx if packet error rate is high */
666 	if (++dev->pkt_cnt > 30) {
667 		dev->pkt_cnt = 0;
668 		dev->pkt_err = 0;
669 	} else {
670 		if (state == rx_cleanup)
671 			dev->pkt_err++;
672 		if (dev->pkt_err > 20)
673 			set_bit(EVENT_RX_KILL, &dev->flags);
674 	}
675 
676 	state = defer_bh(dev, skb, &dev->rxq, state);
677 
678 	if (urb) {
679 		if (netif_running (dev->net) &&
680 		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
681 		    state != unlink_start) {
682 			rx_submit (dev, urb, GFP_ATOMIC);
683 			usb_mark_last_busy(dev->udev);
684 			return;
685 		}
686 		usb_free_urb (urb);
687 	}
688 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
689 }
690 
691 /*-------------------------------------------------------------------------*/
usbnet_pause_rx(struct usbnet * dev)692 void usbnet_pause_rx(struct usbnet *dev)
693 {
694 	set_bit(EVENT_RX_PAUSED, &dev->flags);
695 
696 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
697 }
698 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
699 
usbnet_resume_rx(struct usbnet * dev)700 void usbnet_resume_rx(struct usbnet *dev)
701 {
702 	struct sk_buff *skb;
703 	int num = 0;
704 
705 	local_bh_disable();
706 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
707 
708 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
709 		usbnet_skb_return(dev, skb);
710 		num++;
711 	}
712 
713 	queue_work(system_bh_wq, &dev->bh_work);
714 	local_bh_enable();
715 
716 	netif_dbg(dev, rx_status, dev->net,
717 		  "paused rx queue disabled, %d skbs requeued\n", num);
718 }
719 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
720 
usbnet_purge_paused_rxq(struct usbnet * dev)721 void usbnet_purge_paused_rxq(struct usbnet *dev)
722 {
723 	skb_queue_purge(&dev->rxq_pause);
724 }
725 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
726 
727 /*-------------------------------------------------------------------------*/
728 
729 // unlink pending rx/tx; completion handlers do all other cleanup
730 
unlink_urbs(struct usbnet * dev,struct sk_buff_head * q)731 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
732 {
733 	unsigned long		flags;
734 	struct sk_buff		*skb;
735 	int			count = 0;
736 
737 	spin_lock_irqsave (&q->lock, flags);
738 	while (!skb_queue_empty(q)) {
739 		struct skb_data		*entry;
740 		struct urb		*urb;
741 		int			retval;
742 
743 		skb_queue_walk(q, skb) {
744 			entry = (struct skb_data *) skb->cb;
745 			if (entry->state != unlink_start)
746 				goto found;
747 		}
748 		break;
749 found:
750 		entry->state = unlink_start;
751 		urb = entry->urb;
752 
753 		/*
754 		 * Get reference count of the URB to avoid it to be
755 		 * freed during usb_unlink_urb, which may trigger
756 		 * use-after-free problem inside usb_unlink_urb since
757 		 * usb_unlink_urb is always racing with .complete
758 		 * handler(include defer_bh).
759 		 */
760 		usb_get_urb(urb);
761 		spin_unlock_irqrestore(&q->lock, flags);
762 		// during some PM-driven resume scenarios,
763 		// these (async) unlinks complete immediately
764 		retval = usb_unlink_urb (urb);
765 		if (retval != -EINPROGRESS && retval != 0)
766 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
767 		else
768 			count++;
769 		usb_put_urb(urb);
770 		spin_lock_irqsave(&q->lock, flags);
771 	}
772 	spin_unlock_irqrestore (&q->lock, flags);
773 	return count;
774 }
775 
776 // Flush all pending rx urbs
777 // minidrivers may need to do this when the MTU changes
778 
usbnet_unlink_rx_urbs(struct usbnet * dev)779 void usbnet_unlink_rx_urbs(struct usbnet *dev)
780 {
781 	if (netif_running(dev->net)) {
782 		(void) unlink_urbs (dev, &dev->rxq);
783 		queue_work(system_bh_wq, &dev->bh_work);
784 	}
785 }
786 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
787 
788 /*-------------------------------------------------------------------------*/
789 
wait_skb_queue_empty(struct sk_buff_head * q)790 static void wait_skb_queue_empty(struct sk_buff_head *q)
791 {
792 	unsigned long flags;
793 
794 	spin_lock_irqsave(&q->lock, flags);
795 	while (!skb_queue_empty(q)) {
796 		spin_unlock_irqrestore(&q->lock, flags);
797 		schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
798 		set_current_state(TASK_UNINTERRUPTIBLE);
799 		spin_lock_irqsave(&q->lock, flags);
800 	}
801 	spin_unlock_irqrestore(&q->lock, flags);
802 }
803 
804 // precondition: never called in_interrupt
usbnet_terminate_urbs(struct usbnet * dev)805 static void usbnet_terminate_urbs(struct usbnet *dev)
806 {
807 	DECLARE_WAITQUEUE(wait, current);
808 	int temp;
809 
810 	/* ensure there are no more active urbs */
811 	add_wait_queue(&dev->wait, &wait);
812 	set_current_state(TASK_UNINTERRUPTIBLE);
813 	temp = unlink_urbs(dev, &dev->txq) +
814 		unlink_urbs(dev, &dev->rxq);
815 
816 	/* maybe wait for deletions to finish. */
817 	wait_skb_queue_empty(&dev->rxq);
818 	wait_skb_queue_empty(&dev->txq);
819 	wait_skb_queue_empty(&dev->done);
820 	netif_dbg(dev, ifdown, dev->net,
821 		  "waited for %d urb completions\n", temp);
822 	set_current_state(TASK_RUNNING);
823 	remove_wait_queue(&dev->wait, &wait);
824 }
825 
usbnet_stop(struct net_device * net)826 int usbnet_stop (struct net_device *net)
827 {
828 	struct usbnet		*dev = netdev_priv(net);
829 	const struct driver_info *info = dev->driver_info;
830 	int			retval, pm, mpn;
831 
832 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
833 	netif_stop_queue (net);
834 
835 	netif_info(dev, ifdown, dev->net,
836 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
837 		   net->stats.rx_packets, net->stats.tx_packets,
838 		   net->stats.rx_errors, net->stats.tx_errors);
839 
840 	/* to not race resume */
841 	pm = usb_autopm_get_interface(dev->intf);
842 	/* allow minidriver to stop correctly (wireless devices to turn off
843 	 * radio etc) */
844 	if (info->stop) {
845 		retval = info->stop(dev);
846 		if (retval < 0)
847 			netif_info(dev, ifdown, dev->net,
848 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
849 				   retval,
850 				   dev->udev->bus->bus_name, dev->udev->devpath,
851 				   info->description);
852 	}
853 
854 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
855 		usbnet_terminate_urbs(dev);
856 
857 	usbnet_status_stop(dev);
858 
859 	usbnet_purge_paused_rxq(dev);
860 
861 	mpn = !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
862 
863 	/* deferred work (timer, softirq, task) must also stop */
864 	dev->flags = 0;
865 	timer_delete_sync(&dev->delay);
866 	cancel_work_sync(&dev->bh_work);
867 	cancel_work_sync(&dev->kevent);
868 
869 	/* We have cyclic dependencies. Those calls are needed
870 	 * to break a cycle. We cannot fall into the gaps because
871 	 * we have a flag
872 	 */
873 	cancel_work_sync(&dev->bh_work);
874 	timer_delete_sync(&dev->delay);
875 	cancel_work_sync(&dev->kevent);
876 
877 	if (!pm)
878 		usb_autopm_put_interface(dev->intf);
879 
880 	if (info->manage_power && mpn)
881 		info->manage_power(dev, 0);
882 	else
883 		usb_autopm_put_interface(dev->intf);
884 
885 	return 0;
886 }
887 EXPORT_SYMBOL_GPL(usbnet_stop);
888 
889 /*-------------------------------------------------------------------------*/
890 
891 // posts reads, and enables write queuing
892 
893 // precondition: never called in_interrupt
894 
usbnet_open(struct net_device * net)895 int usbnet_open (struct net_device *net)
896 {
897 	struct usbnet		*dev = netdev_priv(net);
898 	int			retval;
899 	const struct driver_info *info = dev->driver_info;
900 
901 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
902 		netif_info(dev, ifup, dev->net,
903 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
904 			   retval,
905 			   dev->udev->bus->bus_name,
906 			   dev->udev->devpath,
907 			   info->description);
908 		goto done_nopm;
909 	}
910 
911 	// put into "known safe" state
912 	if (info->reset && (retval = info->reset (dev)) < 0) {
913 		netif_info(dev, ifup, dev->net,
914 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
915 			   retval,
916 			   dev->udev->bus->bus_name,
917 			   dev->udev->devpath,
918 			   info->description);
919 		goto done;
920 	}
921 
922 	/* hard_mtu or rx_urb_size may change in reset() */
923 	usbnet_update_max_qlen(dev);
924 
925 	// insist peer be connected
926 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
927 		netif_err(dev, ifup, dev->net, "can't open; %d\n", retval);
928 		goto done;
929 	}
930 
931 	/* start any status interrupt transfer */
932 	if (dev->interrupt) {
933 		retval = usbnet_status_start(dev, GFP_KERNEL);
934 		if (retval < 0) {
935 			netif_err(dev, ifup, dev->net,
936 				  "intr submit %d\n", retval);
937 			goto done;
938 		}
939 	}
940 
941 	set_bit(EVENT_DEV_OPEN, &dev->flags);
942 	netif_start_queue (net);
943 	netif_info(dev, ifup, dev->net,
944 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
945 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
946 		   dev->net->mtu,
947 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
948 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
949 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
950 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
951 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
952 		   "simple");
953 
954 	/* reset rx error state */
955 	dev->pkt_cnt = 0;
956 	dev->pkt_err = 0;
957 	clear_bit(EVENT_RX_KILL, &dev->flags);
958 
959 	// delay posting reads until we're fully open
960 	queue_work(system_bh_wq, &dev->bh_work);
961 	if (info->manage_power) {
962 		retval = info->manage_power(dev, 1);
963 		if (retval < 0) {
964 			retval = 0;
965 			set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
966 		} else {
967 			usb_autopm_put_interface(dev->intf);
968 		}
969 	}
970 	return retval;
971 done:
972 	usb_autopm_put_interface(dev->intf);
973 done_nopm:
974 	return retval;
975 }
976 EXPORT_SYMBOL_GPL(usbnet_open);
977 
978 /*-------------------------------------------------------------------------*/
979 
980 /* ethtool methods; minidrivers may need to add some more, but
981  * they'll probably want to use this base set.
982  */
983 
984 /* These methods are written on the assumption that the device
985  * uses MII
986  */
usbnet_get_link_ksettings_mii(struct net_device * net,struct ethtool_link_ksettings * cmd)987 int usbnet_get_link_ksettings_mii(struct net_device *net,
988 			      struct ethtool_link_ksettings *cmd)
989 {
990 	struct usbnet *dev = netdev_priv(net);
991 
992 	if (!dev->mii.mdio_read)
993 		return -EOPNOTSUPP;
994 
995 	mii_ethtool_get_link_ksettings(&dev->mii, cmd);
996 
997 	return 0;
998 }
999 EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings_mii);
1000 
usbnet_get_link_ksettings_internal(struct net_device * net,struct ethtool_link_ksettings * cmd)1001 int usbnet_get_link_ksettings_internal(struct net_device *net,
1002 					struct ethtool_link_ksettings *cmd)
1003 {
1004 	struct usbnet *dev = netdev_priv(net);
1005 
1006 	/* the assumption that speed is equal on tx and rx
1007 	 * is deeply engrained into the networking layer.
1008 	 * For wireless stuff it is not true.
1009 	 * We assume that rx_speed matters more.
1010 	 */
1011 	if (dev->rx_speed != SPEED_UNSET)
1012 		cmd->base.speed = dev->rx_speed / 1000000;
1013 	else if (dev->tx_speed != SPEED_UNSET)
1014 		cmd->base.speed = dev->tx_speed / 1000000;
1015 	else
1016 		cmd->base.speed = SPEED_UNKNOWN;
1017 
1018 	/* The standard "Universal Serial Bus Class Definitions
1019 	 * for Communications Devices v1.2" does not specify
1020 	 * anything about duplex status.
1021 	 * So set it DUPLEX_UNKNOWN instead of default DUPLEX_HALF.
1022 	 */
1023 	cmd->base.duplex = DUPLEX_UNKNOWN;
1024 
1025 	return 0;
1026 }
1027 EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings_internal);
1028 
usbnet_set_link_ksettings_mii(struct net_device * net,const struct ethtool_link_ksettings * cmd)1029 int usbnet_set_link_ksettings_mii(struct net_device *net,
1030 			      const struct ethtool_link_ksettings *cmd)
1031 {
1032 	struct usbnet *dev = netdev_priv(net);
1033 	int retval;
1034 
1035 	if (!dev->mii.mdio_write)
1036 		return -EOPNOTSUPP;
1037 
1038 	retval = mii_ethtool_set_link_ksettings(&dev->mii, cmd);
1039 
1040 	/* link speed/duplex might have changed */
1041 	if (dev->driver_info->link_reset)
1042 		dev->driver_info->link_reset(dev);
1043 
1044 	/* hard_mtu or rx_urb_size may change in link_reset() */
1045 	usbnet_update_max_qlen(dev);
1046 
1047 	return retval;
1048 }
1049 EXPORT_SYMBOL_GPL(usbnet_set_link_ksettings_mii);
1050 
usbnet_get_link(struct net_device * net)1051 u32 usbnet_get_link (struct net_device *net)
1052 {
1053 	struct usbnet *dev = netdev_priv(net);
1054 
1055 	/* If a check_connect is defined, return its result */
1056 	if (dev->driver_info->check_connect)
1057 		return dev->driver_info->check_connect (dev) == 0;
1058 
1059 	/* if the device has mii operations, use those */
1060 	if (dev->mii.mdio_read)
1061 		return mii_link_ok(&dev->mii);
1062 
1063 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
1064 	return ethtool_op_get_link(net);
1065 }
1066 EXPORT_SYMBOL_GPL(usbnet_get_link);
1067 
usbnet_nway_reset(struct net_device * net)1068 int usbnet_nway_reset(struct net_device *net)
1069 {
1070 	struct usbnet *dev = netdev_priv(net);
1071 
1072 	if (!dev->mii.mdio_write)
1073 		return -EOPNOTSUPP;
1074 
1075 	return mii_nway_restart(&dev->mii);
1076 }
1077 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
1078 
usbnet_get_drvinfo(struct net_device * net,struct ethtool_drvinfo * info)1079 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
1080 {
1081 	struct usbnet *dev = netdev_priv(net);
1082 
1083 	strscpy(info->driver, dev->driver_name, sizeof(info->driver));
1084 	strscpy(info->fw_version, dev->driver_info->description,
1085 		sizeof(info->fw_version));
1086 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
1087 }
1088 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
1089 
usbnet_get_msglevel(struct net_device * net)1090 u32 usbnet_get_msglevel (struct net_device *net)
1091 {
1092 	struct usbnet *dev = netdev_priv(net);
1093 
1094 	return dev->msg_enable;
1095 }
1096 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
1097 
usbnet_set_msglevel(struct net_device * net,u32 level)1098 void usbnet_set_msglevel (struct net_device *net, u32 level)
1099 {
1100 	struct usbnet *dev = netdev_priv(net);
1101 
1102 	dev->msg_enable = level;
1103 }
1104 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
1105 
1106 /* drivers may override default ethtool_ops in their bind() routine */
1107 static const struct ethtool_ops usbnet_ethtool_ops = {
1108 	.get_link		= usbnet_get_link,
1109 	.nway_reset		= usbnet_nway_reset,
1110 	.get_drvinfo		= usbnet_get_drvinfo,
1111 	.get_msglevel		= usbnet_get_msglevel,
1112 	.set_msglevel		= usbnet_set_msglevel,
1113 	.get_ts_info		= ethtool_op_get_ts_info,
1114 	.get_link_ksettings	= usbnet_get_link_ksettings_mii,
1115 	.set_link_ksettings	= usbnet_set_link_ksettings_mii,
1116 };
1117 
1118 /*-------------------------------------------------------------------------*/
1119 
__handle_link_change(struct usbnet * dev)1120 static void __handle_link_change(struct usbnet *dev)
1121 {
1122 	if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
1123 		return;
1124 
1125 	if (test_and_clear_bit(EVENT_LINK_CARRIER_ON, &dev->flags))
1126 		netif_carrier_on(dev->net);
1127 
1128 	if (!netif_carrier_ok(dev->net)) {
1129 		/* kill URBs for reading packets to save bus bandwidth */
1130 		unlink_urbs(dev, &dev->rxq);
1131 
1132 		/*
1133 		 * tx_timeout will unlink URBs for sending packets and
1134 		 * tx queue is stopped by netcore after link becomes off
1135 		 */
1136 	} else {
1137 		/* submitting URBs for reading packets */
1138 		queue_work(system_bh_wq, &dev->bh_work);
1139 	}
1140 
1141 	/* hard_mtu or rx_urb_size may change during link change */
1142 	usbnet_update_max_qlen(dev);
1143 
1144 	clear_bit(EVENT_LINK_CHANGE, &dev->flags);
1145 }
1146 
usbnet_set_rx_mode(struct net_device * net)1147 void usbnet_set_rx_mode(struct net_device *net)
1148 {
1149 	struct usbnet		*dev = netdev_priv(net);
1150 
1151 	usbnet_defer_kevent(dev, EVENT_SET_RX_MODE);
1152 }
1153 EXPORT_SYMBOL_GPL(usbnet_set_rx_mode);
1154 
__handle_set_rx_mode(struct usbnet * dev)1155 static void __handle_set_rx_mode(struct usbnet *dev)
1156 {
1157 	if (dev->driver_info->set_rx_mode)
1158 		(dev->driver_info->set_rx_mode)(dev);
1159 
1160 	clear_bit(EVENT_SET_RX_MODE, &dev->flags);
1161 }
1162 
1163 /* work that cannot be done in interrupt context uses keventd.
1164  *
1165  * NOTE:  with 2.5 we could do more of this using completion callbacks,
1166  * especially now that control transfers can be queued.
1167  */
1168 static void
usbnet_deferred_kevent(struct work_struct * work)1169 usbnet_deferred_kevent (struct work_struct *work)
1170 {
1171 	struct usbnet		*dev =
1172 		container_of(work, struct usbnet, kevent);
1173 	int			status;
1174 
1175 	/* usb_clear_halt() needs a thread context */
1176 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
1177 		unlink_urbs (dev, &dev->txq);
1178 		status = usb_autopm_get_interface(dev->intf);
1179 		if (status < 0)
1180 			goto fail_pipe;
1181 		status = usb_clear_halt (dev->udev, dev->out);
1182 		usb_autopm_put_interface(dev->intf);
1183 		if (status < 0 &&
1184 		    status != -EPIPE &&
1185 		    status != -ESHUTDOWN) {
1186 			if (netif_msg_tx_err (dev))
1187 fail_pipe:
1188 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
1189 					   status);
1190 		} else {
1191 			clear_bit (EVENT_TX_HALT, &dev->flags);
1192 			if (status != -ESHUTDOWN)
1193 				netif_wake_queue (dev->net);
1194 		}
1195 	}
1196 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
1197 		unlink_urbs (dev, &dev->rxq);
1198 		status = usb_autopm_get_interface(dev->intf);
1199 		if (status < 0)
1200 			goto fail_halt;
1201 		status = usb_clear_halt (dev->udev, dev->in);
1202 		usb_autopm_put_interface(dev->intf);
1203 		if (status < 0 &&
1204 		    status != -EPIPE &&
1205 		    status != -ESHUTDOWN) {
1206 			if (netif_msg_rx_err (dev))
1207 fail_halt:
1208 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
1209 					   status);
1210 		} else {
1211 			clear_bit (EVENT_RX_HALT, &dev->flags);
1212 			if (!usbnet_going_away(dev))
1213 				queue_work(system_bh_wq, &dev->bh_work);
1214 		}
1215 	}
1216 
1217 	/* work could resubmit itself forever if memory is tight */
1218 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
1219 		struct urb	*urb = NULL;
1220 		int resched = 1;
1221 
1222 		if (netif_running (dev->net))
1223 			urb = usb_alloc_urb (0, GFP_KERNEL);
1224 		else
1225 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1226 		if (urb != NULL) {
1227 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1228 			status = usb_autopm_get_interface(dev->intf);
1229 			if (status < 0) {
1230 				usb_free_urb(urb);
1231 				goto fail_lowmem;
1232 			}
1233 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
1234 				resched = 0;
1235 			usb_autopm_put_interface(dev->intf);
1236 fail_lowmem:
1237 			if (resched)
1238 				if (!usbnet_going_away(dev))
1239 					queue_work(system_bh_wq, &dev->bh_work);
1240 		}
1241 	}
1242 
1243 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
1244 		const struct driver_info *info = dev->driver_info;
1245 		int			retval = 0;
1246 
1247 		clear_bit (EVENT_LINK_RESET, &dev->flags);
1248 		status = usb_autopm_get_interface(dev->intf);
1249 		if (status < 0)
1250 			goto skip_reset;
1251 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1252 			usb_autopm_put_interface(dev->intf);
1253 skip_reset:
1254 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1255 				    retval,
1256 				    dev->udev->bus->bus_name,
1257 				    dev->udev->devpath,
1258 				    info->description);
1259 		} else {
1260 			usb_autopm_put_interface(dev->intf);
1261 		}
1262 
1263 		/* handle link change from link resetting */
1264 		__handle_link_change(dev);
1265 	}
1266 
1267 	if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
1268 		__handle_link_change(dev);
1269 
1270 	if (test_bit (EVENT_SET_RX_MODE, &dev->flags))
1271 		__handle_set_rx_mode(dev);
1272 
1273 
1274 	if (dev->flags)
1275 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1276 }
1277 
1278 /*-------------------------------------------------------------------------*/
1279 
tx_complete(struct urb * urb)1280 static void tx_complete (struct urb *urb)
1281 {
1282 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1283 	struct skb_data		*entry = (struct skb_data *) skb->cb;
1284 	struct usbnet		*dev = entry->dev;
1285 
1286 	if (urb->status == 0) {
1287 		struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->net->tstats);
1288 		unsigned long flags;
1289 
1290 		flags = u64_stats_update_begin_irqsave(&stats64->syncp);
1291 		u64_stats_add(&stats64->tx_packets, entry->packets);
1292 		u64_stats_add(&stats64->tx_bytes, entry->length);
1293 		u64_stats_update_end_irqrestore(&stats64->syncp, flags);
1294 	} else {
1295 		dev->net->stats.tx_errors++;
1296 
1297 		switch (urb->status) {
1298 		case -EPIPE:
1299 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1300 			break;
1301 
1302 		/* software-driven interface shutdown */
1303 		case -ECONNRESET:		// async unlink
1304 		case -ESHUTDOWN:		// hardware gone
1305 			break;
1306 
1307 		/* like rx, tx gets controller i/o faults during hub_wq
1308 		 * delays and so it uses the same throttling mechanism.
1309 		 */
1310 		case -EPROTO:
1311 		case -ETIME:
1312 		case -EILSEQ:
1313 			usb_mark_last_busy(dev->udev);
1314 			if (!timer_pending (&dev->delay)) {
1315 				mod_timer (&dev->delay,
1316 					jiffies + THROTTLE_JIFFIES);
1317 				netif_dbg(dev, link, dev->net,
1318 					  "tx throttle %d\n", urb->status);
1319 			}
1320 			netif_stop_queue (dev->net);
1321 			break;
1322 		default:
1323 			netif_dbg(dev, tx_err, dev->net,
1324 				  "tx err %d\n", entry->urb->status);
1325 			break;
1326 		}
1327 	}
1328 
1329 	usb_autopm_put_interface_async(dev->intf);
1330 	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1331 }
1332 
1333 /*-------------------------------------------------------------------------*/
1334 
usbnet_tx_timeout(struct net_device * net,unsigned int txqueue)1335 void usbnet_tx_timeout (struct net_device *net, unsigned int txqueue)
1336 {
1337 	struct usbnet		*dev = netdev_priv(net);
1338 
1339 	unlink_urbs (dev, &dev->txq);
1340 	queue_work(system_bh_wq, &dev->bh_work);
1341 	/* this needs to be handled individually because the generic layer
1342 	 * doesn't know what is sufficient and could not restore private
1343 	 * information if a remedy of an unconditional reset were used.
1344 	 */
1345 	if (dev->driver_info->recover)
1346 		(dev->driver_info->recover)(dev);
1347 }
1348 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1349 
1350 /*-------------------------------------------------------------------------*/
1351 
build_dma_sg(const struct sk_buff * skb,struct urb * urb)1352 static int build_dma_sg(const struct sk_buff *skb, struct urb *urb)
1353 {
1354 	unsigned num_sgs, total_len = 0;
1355 	int i, s = 0;
1356 
1357 	num_sgs = skb_shinfo(skb)->nr_frags + 1;
1358 	if (num_sgs == 1)
1359 		return 0;
1360 
1361 	/* reserve one for zero packet */
1362 	urb->sg = kmalloc_array(num_sgs + 1, sizeof(struct scatterlist),
1363 				GFP_ATOMIC);
1364 	if (!urb->sg)
1365 		return -ENOMEM;
1366 
1367 	urb->num_sgs = num_sgs;
1368 	sg_init_table(urb->sg, urb->num_sgs + 1);
1369 
1370 	sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb));
1371 	total_len += skb_headlen(skb);
1372 
1373 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1374 		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
1375 
1376 		total_len += skb_frag_size(f);
1377 		sg_set_page(&urb->sg[i + s], skb_frag_page(f), skb_frag_size(f),
1378 			    skb_frag_off(f));
1379 	}
1380 	urb->transfer_buffer_length = total_len;
1381 
1382 	return 1;
1383 }
1384 
usbnet_start_xmit(struct sk_buff * skb,struct net_device * net)1385 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1386 				     struct net_device *net)
1387 {
1388 	struct usbnet		*dev = netdev_priv(net);
1389 	unsigned int			length;
1390 	struct urb		*urb = NULL;
1391 	struct skb_data		*entry;
1392 	const struct driver_info *info = dev->driver_info;
1393 	unsigned long		flags;
1394 	int retval;
1395 
1396 	if (skb)
1397 		skb_tx_timestamp(skb);
1398 
1399 	// some devices want funky USB-level framing, for
1400 	// win32 driver (usually) and/or hardware quirks
1401 	if (info->tx_fixup) {
1402 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1403 		if (!skb) {
1404 			/* packet collected; minidriver waiting for more */
1405 			if (info->flags & FLAG_MULTI_PACKET)
1406 				goto not_drop;
1407 			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1408 			goto drop;
1409 		}
1410 	}
1411 
1412 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1413 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1414 		goto drop;
1415 	}
1416 
1417 	entry = (struct skb_data *) skb->cb;
1418 	entry->urb = urb;
1419 	entry->dev = dev;
1420 
1421 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1422 			skb->data, skb->len, tx_complete, skb);
1423 	if (dev->can_dma_sg) {
1424 		if (build_dma_sg(skb, urb) < 0)
1425 			goto drop;
1426 	}
1427 	length = urb->transfer_buffer_length;
1428 
1429 	/* don't assume the hardware handles USB_ZERO_PACKET
1430 	 * NOTE:  strictly conforming cdc-ether devices should expect
1431 	 * the ZLP here, but ignore the one-byte packet.
1432 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1433 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1434 	 * packet itself if needed.
1435 	 */
1436 	if (length % dev->maxpacket == 0) {
1437 		if (!(info->flags & FLAG_SEND_ZLP)) {
1438 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1439 				length++;
1440 				if (skb_tailroom(skb) && !urb->num_sgs) {
1441 					skb->data[skb->len] = 0;
1442 					__skb_put(skb, 1);
1443 				} else if (urb->num_sgs)
1444 					sg_set_buf(&urb->sg[urb->num_sgs++],
1445 							dev->padding_pkt, 1);
1446 			}
1447 		} else
1448 			urb->transfer_flags |= URB_ZERO_PACKET;
1449 	}
1450 	urb->transfer_buffer_length = length;
1451 
1452 	if (info->flags & FLAG_MULTI_PACKET) {
1453 		/* Driver has set number of packets and a length delta.
1454 		 * Calculate the complete length and ensure that it's
1455 		 * positive.
1456 		 */
1457 		entry->length += length;
1458 		if (WARN_ON_ONCE(entry->length <= 0))
1459 			entry->length = length;
1460 	} else {
1461 		usbnet_set_skb_tx_stats(skb, 1, length);
1462 	}
1463 
1464 	spin_lock_irqsave(&dev->txq.lock, flags);
1465 	retval = usb_autopm_get_interface_async(dev->intf);
1466 	if (retval < 0) {
1467 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1468 		goto drop;
1469 	}
1470 	if (netif_queue_stopped(net)) {
1471 		usb_autopm_put_interface_async(dev->intf);
1472 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1473 		goto drop;
1474 	}
1475 
1476 #ifdef CONFIG_PM
1477 	/* if this triggers the device is still a sleep */
1478 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1479 		/* transmission will be done in resume */
1480 		usb_anchor_urb(urb, &dev->deferred);
1481 		/* no use to process more packets */
1482 		netif_stop_queue(net);
1483 		usb_put_urb(urb);
1484 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1485 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1486 		goto deferred;
1487 	}
1488 #endif
1489 
1490 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1491 	case -EPIPE:
1492 		netif_stop_queue (net);
1493 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1494 		usb_autopm_put_interface_async(dev->intf);
1495 		break;
1496 	default:
1497 		usb_autopm_put_interface_async(dev->intf);
1498 		netif_dbg(dev, tx_err, dev->net,
1499 			  "tx: submit urb err %d\n", retval);
1500 		break;
1501 	case 0:
1502 		netif_trans_update(net);
1503 		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1504 		if (dev->txq.qlen >= TX_QLEN (dev))
1505 			netif_stop_queue (net);
1506 	}
1507 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1508 
1509 	if (retval) {
1510 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1511 drop:
1512 		dev->net->stats.tx_dropped++;
1513 not_drop:
1514 		if (skb)
1515 			dev_kfree_skb_any (skb);
1516 		if (urb) {
1517 			kfree(urb->sg);
1518 			usb_free_urb(urb);
1519 		}
1520 	} else
1521 		netif_dbg(dev, tx_queued, dev->net,
1522 			  "> tx, len %u, type 0x%x\n", length, skb->protocol);
1523 #ifdef CONFIG_PM
1524 deferred:
1525 #endif
1526 	return NETDEV_TX_OK;
1527 }
1528 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1529 
rx_alloc_submit(struct usbnet * dev,gfp_t flags)1530 static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1531 {
1532 	struct urb	*urb;
1533 	int		i;
1534 	int		ret = 0;
1535 
1536 	/* don't refill the queue all at once */
1537 	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1538 		urb = usb_alloc_urb(0, flags);
1539 		if (urb != NULL) {
1540 			ret = rx_submit(dev, urb, flags);
1541 			if (ret)
1542 				goto err;
1543 		} else {
1544 			ret = -ENOMEM;
1545 			goto err;
1546 		}
1547 	}
1548 err:
1549 	return ret;
1550 }
1551 
usb_free_skb(struct sk_buff * skb)1552 static inline void usb_free_skb(struct sk_buff *skb)
1553 {
1554 	struct skb_data *entry = (struct skb_data *)skb->cb;
1555 
1556 	usb_free_urb(entry->urb);
1557 	dev_kfree_skb(skb);
1558 }
1559 
1560 /*-------------------------------------------------------------------------*/
1561 
1562 // work (work deferred from completions, in_irq) or timer
1563 
usbnet_bh(struct timer_list * t)1564 static void usbnet_bh (struct timer_list *t)
1565 {
1566 	struct usbnet		*dev = timer_container_of(dev, t, delay);
1567 	struct sk_buff		*skb;
1568 	struct skb_data		*entry;
1569 
1570 	while ((skb = skb_dequeue (&dev->done))) {
1571 		entry = (struct skb_data *) skb->cb;
1572 		switch (entry->state) {
1573 		case rx_done:
1574 			if (rx_process(dev, skb))
1575 				usb_free_skb(skb);
1576 			continue;
1577 		case tx_done:
1578 			kfree(entry->urb->sg);
1579 			fallthrough;
1580 		case rx_cleanup:
1581 			usb_free_skb(skb);
1582 			continue;
1583 		default:
1584 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1585 		}
1586 	}
1587 
1588 	/* restart RX again after disabling due to high error rate */
1589 	clear_bit(EVENT_RX_KILL, &dev->flags);
1590 
1591 	/* waiting for all pending urbs to complete?
1592 	 * only then can we forgo submitting anew
1593 	 */
1594 	if (waitqueue_active(&dev->wait)) {
1595 		if (dev->txq.qlen + dev->rxq.qlen + dev->done.qlen == 0)
1596 			wake_up_all(&dev->wait);
1597 
1598 	// or are we maybe short a few urbs?
1599 	} else if (netif_running (dev->net) &&
1600 		   netif_device_present (dev->net) &&
1601 		   netif_carrier_ok(dev->net) &&
1602 		   !usbnet_going_away(dev) &&
1603 		   !timer_pending(&dev->delay) &&
1604 		   !test_bit(EVENT_RX_PAUSED, &dev->flags) &&
1605 		   !test_bit(EVENT_RX_HALT, &dev->flags)) {
1606 		int	temp = dev->rxq.qlen;
1607 
1608 		if (temp < RX_QLEN(dev)) {
1609 			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1610 				return;
1611 			if (temp != dev->rxq.qlen)
1612 				netif_dbg(dev, link, dev->net,
1613 					  "rxqlen %d --> %d\n",
1614 					  temp, dev->rxq.qlen);
1615 			if (dev->rxq.qlen < RX_QLEN(dev))
1616 				queue_work(system_bh_wq, &dev->bh_work);
1617 		}
1618 		if (dev->txq.qlen < TX_QLEN (dev))
1619 			netif_wake_queue (dev->net);
1620 	}
1621 }
1622 
usbnet_bh_work(struct work_struct * work)1623 static void usbnet_bh_work(struct work_struct *work)
1624 {
1625 	struct usbnet *dev = from_work(dev, work, bh_work);
1626 
1627 	usbnet_bh(&dev->delay);
1628 }
1629 
1630 
1631 /*-------------------------------------------------------------------------
1632  *
1633  * USB Device Driver support
1634  *
1635  *-------------------------------------------------------------------------*/
1636 
1637 // precondition: never called in_interrupt
1638 
usbnet_disconnect(struct usb_interface * intf)1639 void usbnet_disconnect (struct usb_interface *intf)
1640 {
1641 	struct usbnet		*dev;
1642 	struct usb_device	*xdev;
1643 	struct net_device	*net;
1644 	struct urb		*urb;
1645 
1646 	dev = usb_get_intfdata(intf);
1647 	usb_set_intfdata(intf, NULL);
1648 	if (!dev)
1649 		return;
1650 	usbnet_mark_going_away(dev);
1651 
1652 	xdev = interface_to_usbdev (intf);
1653 
1654 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1655 		   intf->dev.driver->name,
1656 		   xdev->bus->bus_name, xdev->devpath,
1657 		   dev->driver_info->description);
1658 
1659 	net = dev->net;
1660 	unregister_netdev (net);
1661 
1662 	while ((urb = usb_get_from_anchor(&dev->deferred))) {
1663 		dev_kfree_skb(urb->context);
1664 		kfree(urb->sg);
1665 		usb_free_urb(urb);
1666 	}
1667 
1668 	if (dev->driver_info->unbind)
1669 		dev->driver_info->unbind(dev, intf);
1670 
1671 	usb_kill_urb(dev->interrupt);
1672 	usb_free_urb(dev->interrupt);
1673 	kfree(dev->padding_pkt);
1674 
1675 	free_netdev(net);
1676 }
1677 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1678 
1679 static const struct net_device_ops usbnet_netdev_ops = {
1680 	.ndo_open		= usbnet_open,
1681 	.ndo_stop		= usbnet_stop,
1682 	.ndo_start_xmit		= usbnet_start_xmit,
1683 	.ndo_tx_timeout		= usbnet_tx_timeout,
1684 	.ndo_set_rx_mode	= usbnet_set_rx_mode,
1685 	.ndo_change_mtu		= usbnet_change_mtu,
1686 	.ndo_set_mac_address 	= eth_mac_addr,
1687 	.ndo_validate_addr	= eth_validate_addr,
1688 };
1689 
1690 /*-------------------------------------------------------------------------*/
1691 
1692 // precondition: never called in_interrupt
1693 
1694 static const struct device_type wlan_type = {
1695 	.name	= "wlan",
1696 };
1697 
1698 static const struct device_type wwan_type = {
1699 	.name	= "wwan",
1700 };
1701 
1702 int
usbnet_probe(struct usb_interface * udev,const struct usb_device_id * prod)1703 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1704 {
1705 	struct usbnet			*dev;
1706 	struct net_device		*net;
1707 	struct usb_host_interface	*interface;
1708 	const struct driver_info	*info;
1709 	struct usb_device		*xdev;
1710 	int				status;
1711 	const char			*name;
1712 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1713 
1714 	/* usbnet already took usb runtime pm, so have to enable the feature
1715 	 * for usb interface, otherwise usb_autopm_get_interface may return
1716 	 * failure if RUNTIME_PM is enabled.
1717 	 */
1718 	if (!driver->supports_autosuspend) {
1719 		driver->supports_autosuspend = 1;
1720 		pm_runtime_enable(&udev->dev);
1721 	}
1722 
1723 	name = udev->dev.driver->name;
1724 	info = (const struct driver_info *) prod->driver_info;
1725 	if (!info) {
1726 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1727 		return -ENODEV;
1728 	}
1729 	xdev = interface_to_usbdev (udev);
1730 	interface = udev->cur_altsetting;
1731 
1732 	status = -ENOMEM;
1733 
1734 	// set up our own records
1735 	net = alloc_etherdev(sizeof(*dev));
1736 	if (!net)
1737 		goto out;
1738 
1739 	/* netdev_printk() needs this so do it as early as possible */
1740 	SET_NETDEV_DEV(net, &udev->dev);
1741 
1742 	dev = netdev_priv(net);
1743 	dev->udev = xdev;
1744 	dev->intf = udev;
1745 	dev->driver_info = info;
1746 	dev->driver_name = name;
1747 	dev->rx_speed = SPEED_UNSET;
1748 	dev->tx_speed = SPEED_UNSET;
1749 
1750 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1751 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1752 	init_waitqueue_head(&dev->wait);
1753 	skb_queue_head_init (&dev->rxq);
1754 	skb_queue_head_init (&dev->txq);
1755 	skb_queue_head_init (&dev->done);
1756 	skb_queue_head_init(&dev->rxq_pause);
1757 	INIT_WORK(&dev->bh_work, usbnet_bh_work);
1758 	INIT_WORK (&dev->kevent, usbnet_deferred_kevent);
1759 	init_usb_anchor(&dev->deferred);
1760 	timer_setup(&dev->delay, usbnet_bh, 0);
1761 	mutex_init (&dev->phy_mutex);
1762 	mutex_init(&dev->interrupt_mutex);
1763 	dev->interrupt_count = 0;
1764 
1765 	dev->net = net;
1766 	strscpy(net->name, "usb%d", sizeof(net->name));
1767 
1768 	/* rx and tx sides can use different message sizes;
1769 	 * bind() should set rx_urb_size in that case.
1770 	 */
1771 	dev->hard_mtu = net->mtu + net->hard_header_len;
1772 	net->min_mtu = 0;
1773 	net->max_mtu = ETH_MAX_MTU;
1774 
1775 	net->netdev_ops = &usbnet_netdev_ops;
1776 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1777 	net->ethtool_ops = &usbnet_ethtool_ops;
1778 	net->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
1779 
1780 	// allow device-specific bind/init procedures
1781 	// NOTE net->name still not usable ...
1782 	if (info->bind) {
1783 		status = info->bind (dev, udev);
1784 		if (status < 0)
1785 			goto out1;
1786 
1787 		/* heuristic: rename to "eth%d" if we are not sure this link
1788 		 * is two-host (these links keep "usb%d")
1789 		 */
1790 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1791 		    !usbnet_needs_usb_name_format(dev, net))
1792 			strscpy(net->name, "eth%d", sizeof(net->name));
1793 		/* WLAN devices should always be named "wlan%d" */
1794 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1795 			strscpy(net->name, "wlan%d", sizeof(net->name));
1796 		/* WWAN devices should always be named "wwan%d" */
1797 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1798 			strscpy(net->name, "wwan%d", sizeof(net->name));
1799 
1800 		/* devices that cannot do ARP */
1801 		if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1802 			net->flags |= IFF_NOARP;
1803 
1804 		/* maybe the remote can't receive an Ethernet MTU */
1805 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1806 			net->mtu = dev->hard_mtu - net->hard_header_len;
1807 	} else if (!info->in || !info->out)
1808 		status = usbnet_get_endpoints (dev, udev);
1809 	else {
1810 		u8 ep_addrs[3] = {
1811 			info->in + USB_DIR_IN, info->out + USB_DIR_OUT, 0
1812 		};
1813 
1814 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1815 		dev->out = usb_sndbulkpipe (xdev, info->out);
1816 		if (!(info->flags & FLAG_NO_SETINT))
1817 			status = usb_set_interface (xdev,
1818 				interface->desc.bInterfaceNumber,
1819 				interface->desc.bAlternateSetting);
1820 		else
1821 			status = 0;
1822 
1823 		if (status == 0 && !usb_check_bulk_endpoints(udev, ep_addrs))
1824 			status = -EINVAL;
1825 	}
1826 	if (status >= 0 && dev->status)
1827 		status = init_status (dev, udev);
1828 	if (status < 0)
1829 		goto out3;
1830 
1831 	if (!dev->rx_urb_size)
1832 		dev->rx_urb_size = dev->hard_mtu;
1833 	dev->maxpacket = usb_maxpacket(dev->udev, dev->out);
1834 	if (dev->maxpacket == 0) {
1835 		/* that is a broken device */
1836 		status = -ENODEV;
1837 		goto out4;
1838 	}
1839 
1840 	/* this flags the device for user space */
1841 	if (!is_valid_ether_addr(net->dev_addr))
1842 		eth_hw_addr_random(net);
1843 
1844 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1845 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1846 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1847 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1848 
1849 	/* initialize max rx_qlen and tx_qlen */
1850 	usbnet_update_max_qlen(dev);
1851 
1852 	if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&
1853 		!(info->flags & FLAG_MULTI_PACKET)) {
1854 		dev->padding_pkt = kzalloc(1, GFP_KERNEL);
1855 		if (!dev->padding_pkt) {
1856 			status = -ENOMEM;
1857 			goto out4;
1858 		}
1859 	}
1860 
1861 	status = register_netdev (net);
1862 	if (status)
1863 		goto out5;
1864 	netif_info(dev, probe, dev->net,
1865 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1866 		   udev->dev.driver->name,
1867 		   xdev->bus->bus_name, xdev->devpath,
1868 		   dev->driver_info->description,
1869 		   net->dev_addr);
1870 
1871 	// ok, it's ready to go.
1872 	usb_set_intfdata (udev, dev);
1873 
1874 	netif_device_attach (net);
1875 
1876 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1877 		usbnet_link_change(dev, 0, 0);
1878 
1879 	return 0;
1880 
1881 out5:
1882 	kfree(dev->padding_pkt);
1883 out4:
1884 	usb_free_urb(dev->interrupt);
1885 out3:
1886 	if (info->unbind)
1887 		info->unbind (dev, udev);
1888 out1:
1889 	/* subdrivers must undo all they did in bind() if they
1890 	 * fail it, but we may fail later and a deferred kevent
1891 	 * may trigger an error resubmitting itself and, worse,
1892 	 * schedule a timer. So we kill it all just in case.
1893 	 */
1894 	usbnet_mark_going_away(dev);
1895 	cancel_work_sync(&dev->kevent);
1896 	timer_delete_sync(&dev->delay);
1897 	free_netdev(net);
1898 out:
1899 	return status;
1900 }
1901 EXPORT_SYMBOL_GPL(usbnet_probe);
1902 
1903 /*-------------------------------------------------------------------------*/
1904 
1905 /*
1906  * suspend the whole driver as soon as the first interface is suspended
1907  * resume only when the last interface is resumed
1908  */
1909 
usbnet_suspend(struct usb_interface * intf,pm_message_t message)1910 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1911 {
1912 	struct usbnet		*dev = usb_get_intfdata(intf);
1913 
1914 	if (!dev->suspend_count++) {
1915 		spin_lock_irq(&dev->txq.lock);
1916 		/* don't autosuspend while transmitting */
1917 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1918 			dev->suspend_count--;
1919 			spin_unlock_irq(&dev->txq.lock);
1920 			return -EBUSY;
1921 		} else {
1922 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1923 			spin_unlock_irq(&dev->txq.lock);
1924 		}
1925 		/*
1926 		 * accelerate emptying of the rx and queues, to avoid
1927 		 * having everything error out.
1928 		 */
1929 		netif_device_detach (dev->net);
1930 		usbnet_terminate_urbs(dev);
1931 		__usbnet_status_stop_force(dev);
1932 
1933 		/*
1934 		 * reattach so runtime management can use and
1935 		 * wake the device
1936 		 */
1937 		netif_device_attach (dev->net);
1938 	}
1939 	return 0;
1940 }
1941 EXPORT_SYMBOL_GPL(usbnet_suspend);
1942 
usbnet_resume(struct usb_interface * intf)1943 int usbnet_resume (struct usb_interface *intf)
1944 {
1945 	struct usbnet		*dev = usb_get_intfdata(intf);
1946 	struct sk_buff          *skb;
1947 	struct urb              *res;
1948 	int                     retval;
1949 
1950 	if (!--dev->suspend_count) {
1951 		/* resume interrupt URB if it was previously submitted */
1952 		__usbnet_status_start_force(dev, GFP_NOIO);
1953 
1954 		spin_lock_irq(&dev->txq.lock);
1955 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1956 
1957 			skb = (struct sk_buff *)res->context;
1958 			retval = usb_submit_urb(res, GFP_ATOMIC);
1959 			if (retval < 0) {
1960 				dev_kfree_skb_any(skb);
1961 				kfree(res->sg);
1962 				usb_free_urb(res);
1963 				usb_autopm_put_interface_async(dev->intf);
1964 			} else {
1965 				netif_trans_update(dev->net);
1966 				__skb_queue_tail(&dev->txq, skb);
1967 			}
1968 		}
1969 
1970 		smp_mb();
1971 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1972 		spin_unlock_irq(&dev->txq.lock);
1973 
1974 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1975 			/* handle remote wakeup ASAP
1976 			 * we cannot race against stop
1977 			 */
1978 			if (netif_device_present(dev->net) &&
1979 				!timer_pending(&dev->delay) &&
1980 				!test_bit(EVENT_RX_HALT, &dev->flags))
1981 					rx_alloc_submit(dev, GFP_NOIO);
1982 
1983 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1984 				netif_tx_wake_all_queues(dev->net);
1985 			queue_work(system_bh_wq, &dev->bh_work);
1986 		}
1987 	}
1988 
1989 	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1990 		usb_autopm_get_interface_no_resume(intf);
1991 
1992 	return 0;
1993 }
1994 EXPORT_SYMBOL_GPL(usbnet_resume);
1995 
1996 /*
1997  * Either a subdriver implements manage_power, then it is assumed to always
1998  * be ready to be suspended or it reports the readiness to be suspended
1999  * explicitly
2000  */
usbnet_device_suggests_idle(struct usbnet * dev)2001 void usbnet_device_suggests_idle(struct usbnet *dev)
2002 {
2003 	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
2004 		dev->intf->needs_remote_wakeup = 1;
2005 		usb_autopm_put_interface_async(dev->intf);
2006 	}
2007 }
2008 EXPORT_SYMBOL(usbnet_device_suggests_idle);
2009 
2010 /*
2011  * For devices that can do without special commands
2012  */
usbnet_manage_power(struct usbnet * dev,int on)2013 int usbnet_manage_power(struct usbnet *dev, int on)
2014 {
2015 	dev->intf->needs_remote_wakeup = on;
2016 	return 0;
2017 }
2018 EXPORT_SYMBOL(usbnet_manage_power);
2019 
usbnet_link_change(struct usbnet * dev,bool link,bool need_reset)2020 void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
2021 {
2022 	/* update link after link is reseted */
2023 	if (link && !need_reset) {
2024 		set_bit(EVENT_LINK_CARRIER_ON, &dev->flags);
2025 	} else {
2026 		clear_bit(EVENT_LINK_CARRIER_ON, &dev->flags);
2027 		netif_carrier_off(dev->net);
2028 	}
2029 
2030 	if (need_reset && link)
2031 		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
2032 	else
2033 		usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
2034 }
2035 EXPORT_SYMBOL(usbnet_link_change);
2036 
2037 /*-------------------------------------------------------------------------*/
__usbnet_read_cmd(struct usbnet * dev,u8 cmd,u8 reqtype,u16 value,u16 index,void * data,u16 size)2038 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2039 			     u16 value, u16 index, void *data, u16 size)
2040 {
2041 	void *buf = NULL;
2042 	int err = -ENOMEM;
2043 
2044 	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
2045 		   " value=0x%04x index=0x%04x size=%d\n",
2046 		   cmd, reqtype, value, index, size);
2047 
2048 	if (size) {
2049 		buf = kmalloc(size, GFP_NOIO);
2050 		if (!buf)
2051 			goto out;
2052 	}
2053 
2054 	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
2055 			      cmd, reqtype, value, index, buf, size,
2056 			      USB_CTRL_GET_TIMEOUT);
2057 	if (err > 0 && err <= size) {
2058 		if (data)
2059 			memcpy(data, buf, err);
2060 		else
2061 			netdev_dbg(dev->net,
2062 				   "Huh? Data requested but thrown away.\n");
2063 	}
2064 	kfree(buf);
2065 out:
2066 	return err;
2067 }
2068 
__usbnet_write_cmd(struct usbnet * dev,u8 cmd,u8 reqtype,u16 value,u16 index,const void * data,u16 size)2069 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2070 			      u16 value, u16 index, const void *data,
2071 			      u16 size)
2072 {
2073 	void *buf = NULL;
2074 	int err = -ENOMEM;
2075 
2076 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2077 		   " value=0x%04x index=0x%04x size=%d\n",
2078 		   cmd, reqtype, value, index, size);
2079 
2080 	if (data) {
2081 		buf = kmemdup(data, size, GFP_NOIO);
2082 		if (!buf)
2083 			goto out;
2084 	} else {
2085         if (size) {
2086             WARN_ON_ONCE(1);
2087             err = -EINVAL;
2088             goto out;
2089         }
2090     }
2091 
2092 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
2093 			      cmd, reqtype, value, index, buf, size,
2094 			      USB_CTRL_SET_TIMEOUT);
2095 	kfree(buf);
2096 
2097 out:
2098 	return err;
2099 }
2100 
2101 /*
2102  * The function can't be called inside suspend/resume callback,
2103  * otherwise deadlock will be caused.
2104  */
usbnet_read_cmd(struct usbnet * dev,u8 cmd,u8 reqtype,u16 value,u16 index,void * data,u16 size)2105 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2106 		    u16 value, u16 index, void *data, u16 size)
2107 {
2108 	int ret;
2109 
2110 	if (usb_autopm_get_interface(dev->intf) < 0)
2111 		return -ENODEV;
2112 	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2113 				data, size);
2114 	usb_autopm_put_interface(dev->intf);
2115 	return ret;
2116 }
2117 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
2118 
2119 /*
2120  * The function can't be called inside suspend/resume callback,
2121  * otherwise deadlock will be caused.
2122  */
usbnet_write_cmd(struct usbnet * dev,u8 cmd,u8 reqtype,u16 value,u16 index,const void * data,u16 size)2123 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2124 		     u16 value, u16 index, const void *data, u16 size)
2125 {
2126 	int ret;
2127 
2128 	if (usb_autopm_get_interface(dev->intf) < 0)
2129 		return -ENODEV;
2130 	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2131 				 data, size);
2132 	usb_autopm_put_interface(dev->intf);
2133 	return ret;
2134 }
2135 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
2136 
2137 /*
2138  * The function can be called inside suspend/resume callback safely
2139  * and should only be called by suspend/resume callback generally.
2140  */
usbnet_read_cmd_nopm(struct usbnet * dev,u8 cmd,u8 reqtype,u16 value,u16 index,void * data,u16 size)2141 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2142 			  u16 value, u16 index, void *data, u16 size)
2143 {
2144 	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2145 				 data, size);
2146 }
2147 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
2148 
2149 /*
2150  * The function can be called inside suspend/resume callback safely
2151  * and should only be called by suspend/resume callback generally.
2152  */
usbnet_write_cmd_nopm(struct usbnet * dev,u8 cmd,u8 reqtype,u16 value,u16 index,const void * data,u16 size)2153 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2154 			  u16 value, u16 index, const void *data,
2155 			  u16 size)
2156 {
2157 	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2158 				  data, size);
2159 }
2160 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
2161 
usbnet_async_cmd_cb(struct urb * urb)2162 static void usbnet_async_cmd_cb(struct urb *urb)
2163 {
2164 	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
2165 	int status = urb->status;
2166 
2167 	if (status < 0)
2168 		dev_dbg(&urb->dev->dev, "%s failed with %d",
2169 			__func__, status);
2170 
2171 	kfree(req);
2172 	usb_free_urb(urb);
2173 }
2174 
2175 /*
2176  * The caller must make sure that device can't be put into suspend
2177  * state until the control URB completes.
2178  */
usbnet_write_cmd_async(struct usbnet * dev,u8 cmd,u8 reqtype,u16 value,u16 index,const void * data,u16 size)2179 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
2180 			   u16 value, u16 index, const void *data, u16 size)
2181 {
2182 	struct usb_ctrlrequest *req;
2183 	struct urb *urb;
2184 	int err = -ENOMEM;
2185 	void *buf = NULL;
2186 
2187 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2188 		   " value=0x%04x index=0x%04x size=%d\n",
2189 		   cmd, reqtype, value, index, size);
2190 
2191 	urb = usb_alloc_urb(0, GFP_ATOMIC);
2192 	if (!urb)
2193 		goto fail;
2194 
2195 	if (data) {
2196 		buf = kmemdup(data, size, GFP_ATOMIC);
2197 		if (!buf) {
2198 			netdev_err(dev->net, "Error allocating buffer"
2199 				   " in %s!\n", __func__);
2200 			goto fail_free_urb;
2201 		}
2202 	}
2203 
2204 	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
2205 	if (!req)
2206 		goto fail_free_buf;
2207 
2208 	req->bRequestType = reqtype;
2209 	req->bRequest = cmd;
2210 	req->wValue = cpu_to_le16(value);
2211 	req->wIndex = cpu_to_le16(index);
2212 	req->wLength = cpu_to_le16(size);
2213 
2214 	usb_fill_control_urb(urb, dev->udev,
2215 			     usb_sndctrlpipe(dev->udev, 0),
2216 			     (void *)req, buf, size,
2217 			     usbnet_async_cmd_cb, req);
2218 	urb->transfer_flags |= URB_FREE_BUFFER;
2219 
2220 	err = usb_submit_urb(urb, GFP_ATOMIC);
2221 	if (err < 0) {
2222 		netdev_err(dev->net, "Error submitting the control"
2223 			   " message: status=%d\n", err);
2224 		goto fail_free_all;
2225 	}
2226 	return 0;
2227 
2228 fail_free_all:
2229 	kfree(req);
2230 fail_free_buf:
2231 	kfree(buf);
2232 	/*
2233 	 * avoid a double free
2234 	 * needed because the flag can be set only
2235 	 * after filling the URB
2236 	 */
2237 	urb->transfer_flags = 0;
2238 fail_free_urb:
2239 	usb_free_urb(urb);
2240 fail:
2241 	return err;
2242 
2243 }
2244 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
2245 /*-------------------------------------------------------------------------*/
2246 
usbnet_init(void)2247 static int __init usbnet_init(void)
2248 {
2249 	/* Compiler should optimize this out. */
2250 	BUILD_BUG_ON(
2251 		sizeof_field(struct sk_buff, cb) < sizeof(struct skb_data));
2252 
2253 	return 0;
2254 }
2255 module_init(usbnet_init);
2256 
usbnet_exit(void)2257 static void __exit usbnet_exit(void)
2258 {
2259 }
2260 module_exit(usbnet_exit);
2261 
2262 MODULE_AUTHOR("David Brownell");
2263 MODULE_DESCRIPTION("USB network driver framework");
2264 MODULE_LICENSE("GPL");
2265