xref: /kernel/linux/linux-5.10/drivers/net/usb/usbnet.c (revision 8c2ecf20)
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// #define	DEBUG			// error path messages, extra info
21// #define	VERBOSE			// more; success messages
22
23#include <linux/module.h>
24#include <linux/init.h>
25#include <linux/netdevice.h>
26#include <linux/etherdevice.h>
27#include <linux/ctype.h>
28#include <linux/ethtool.h>
29#include <linux/workqueue.h>
30#include <linux/mii.h>
31#include <linux/usb.h>
32#include <linux/usb/usbnet.h>
33#include <linux/slab.h>
34#include <linux/kernel.h>
35#include <linux/pm_runtime.h>
36
37/*-------------------------------------------------------------------------*/
38
39/*
40 * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
41 * Several dozen bytes of IPv4 data can fit in two such transactions.
42 * One maximum size Ethernet packet takes twenty four of them.
43 * For high speed, each frame comfortably fits almost 36 max size
44 * Ethernet packets (so queues should be bigger).
45 *
46 * The goal is to let the USB host controller be busy for 5msec or
47 * more before an irq is required, under load.  Jumbograms change
48 * the equation.
49 */
50#define	MAX_QUEUE_MEMORY	(60 * 1518)
51#define	RX_QLEN(dev)		((dev)->rx_qlen)
52#define	TX_QLEN(dev)		((dev)->tx_qlen)
53
54// reawaken network queue this soon after stopping; else watchdog barks
55#define TX_TIMEOUT_JIFFIES	(5*HZ)
56
57/* throttle rx/tx briefly after some faults, so hub_wq might disconnect()
58 * us (it polls at HZ/4 usually) before we report too many false errors.
59 */
60#define THROTTLE_JIFFIES	(HZ/8)
61
62// between wakeups
63#define UNLINK_TIMEOUT_MS	3
64
65/*-------------------------------------------------------------------------*/
66
67// randomly generated ethernet address
68static u8	node_id [ETH_ALEN];
69
70/* use ethtool to change the level for any given device */
71static int msg_level = -1;
72module_param (msg_level, int, 0);
73MODULE_PARM_DESC (msg_level, "Override default message level");
74
75/*-------------------------------------------------------------------------*/
76
77/* handles CDC Ethernet and many other network "bulk data" interfaces */
78int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
79{
80	int				tmp;
81	struct usb_host_interface	*alt = NULL;
82	struct usb_host_endpoint	*in = NULL, *out = NULL;
83	struct usb_host_endpoint	*status = NULL;
84
85	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
86		unsigned	ep;
87
88		in = out = status = NULL;
89		alt = intf->altsetting + tmp;
90
91		/* take the first altsetting with in-bulk + out-bulk;
92		 * remember any status endpoint, just in case;
93		 * ignore other endpoints and altsettings.
94		 */
95		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
96			struct usb_host_endpoint	*e;
97			int				intr = 0;
98
99			e = alt->endpoint + ep;
100
101			/* ignore endpoints which cannot transfer data */
102			if (!usb_endpoint_maxp(&e->desc))
103				continue;
104
105			switch (e->desc.bmAttributes) {
106			case USB_ENDPOINT_XFER_INT:
107				if (!usb_endpoint_dir_in(&e->desc))
108					continue;
109				intr = 1;
110				fallthrough;
111			case USB_ENDPOINT_XFER_BULK:
112				break;
113			default:
114				continue;
115			}
116			if (usb_endpoint_dir_in(&e->desc)) {
117				if (!intr && !in)
118					in = e;
119				else if (intr && !status)
120					status = e;
121			} else {
122				if (!out)
123					out = e;
124			}
125		}
126		if (in && out)
127			break;
128	}
129	if (!alt || !in || !out)
130		return -EINVAL;
131
132	if (alt->desc.bAlternateSetting != 0 ||
133	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
134		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
135				alt->desc.bAlternateSetting);
136		if (tmp < 0)
137			return tmp;
138	}
139
140	dev->in = usb_rcvbulkpipe (dev->udev,
141			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
142	dev->out = usb_sndbulkpipe (dev->udev,
143			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
144	dev->status = status;
145	return 0;
146}
147EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
148
149int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
150{
151	int 		tmp = -1, ret;
152	unsigned char	buf [13];
153
154	ret = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
155	if (ret == 12)
156		tmp = hex2bin(dev->net->dev_addr, buf, 6);
157	if (tmp < 0) {
158		dev_dbg(&dev->udev->dev,
159			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
160		if (ret >= 0)
161			ret = -EINVAL;
162		return ret;
163	}
164	return 0;
165}
166EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
167
168static void intr_complete (struct urb *urb)
169{
170	struct usbnet	*dev = urb->context;
171	int		status = urb->status;
172
173	switch (status) {
174	/* success */
175	case 0:
176		dev->driver_info->status(dev, urb);
177		break;
178
179	/* software-driven interface shutdown */
180	case -ENOENT:		/* urb killed */
181	case -ESHUTDOWN:	/* hardware gone */
182		netif_dbg(dev, ifdown, dev->net,
183			  "intr shutdown, code %d\n", status);
184		return;
185
186	/* NOTE:  not throttling like RX/TX, since this endpoint
187	 * already polls infrequently
188	 */
189	default:
190		netdev_dbg(dev->net, "intr status %d\n", status);
191		break;
192	}
193
194	status = usb_submit_urb (urb, GFP_ATOMIC);
195	if (status != 0)
196		netif_err(dev, timer, dev->net,
197			  "intr resubmit --> %d\n", status);
198}
199
200static int init_status (struct usbnet *dev, struct usb_interface *intf)
201{
202	char		*buf = NULL;
203	unsigned	pipe = 0;
204	unsigned	maxp;
205	unsigned	period;
206
207	if (!dev->driver_info->status)
208		return 0;
209
210	pipe = usb_rcvintpipe (dev->udev,
211			dev->status->desc.bEndpointAddress
212				& USB_ENDPOINT_NUMBER_MASK);
213	maxp = usb_maxpacket (dev->udev, pipe, 0);
214
215	/* avoid 1 msec chatter:  min 8 msec poll rate */
216	period = max ((int) dev->status->desc.bInterval,
217		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
218
219	buf = kmalloc (maxp, GFP_KERNEL);
220	if (buf) {
221		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
222		if (!dev->interrupt) {
223			kfree (buf);
224			return -ENOMEM;
225		} else {
226			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
227				buf, maxp, intr_complete, dev, period);
228			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
229			dev_dbg(&intf->dev,
230				"status ep%din, %d bytes period %d\n",
231				usb_pipeendpoint(pipe), maxp, period);
232		}
233	}
234	return 0;
235}
236
237/* Submit the interrupt URB if not previously submitted, increasing refcount */
238int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
239{
240	int ret = 0;
241
242	WARN_ON_ONCE(dev->interrupt == NULL);
243	if (dev->interrupt) {
244		mutex_lock(&dev->interrupt_mutex);
245
246		if (++dev->interrupt_count == 1)
247			ret = usb_submit_urb(dev->interrupt, mem_flags);
248
249		dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
250			dev->interrupt_count);
251		mutex_unlock(&dev->interrupt_mutex);
252	}
253	return ret;
254}
255EXPORT_SYMBOL_GPL(usbnet_status_start);
256
257/* For resume; submit interrupt URB if previously submitted */
258static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
259{
260	int ret = 0;
261
262	mutex_lock(&dev->interrupt_mutex);
263	if (dev->interrupt_count) {
264		ret = usb_submit_urb(dev->interrupt, mem_flags);
265		dev_dbg(&dev->udev->dev,
266			"submitted interrupt URB for resume\n");
267	}
268	mutex_unlock(&dev->interrupt_mutex);
269	return ret;
270}
271
272/* Kill the interrupt URB if all submitters want it killed */
273void usbnet_status_stop(struct usbnet *dev)
274{
275	if (dev->interrupt) {
276		mutex_lock(&dev->interrupt_mutex);
277		WARN_ON(dev->interrupt_count == 0);
278
279		if (dev->interrupt_count && --dev->interrupt_count == 0)
280			usb_kill_urb(dev->interrupt);
281
282		dev_dbg(&dev->udev->dev,
283			"decremented interrupt URB count to %d\n",
284			dev->interrupt_count);
285		mutex_unlock(&dev->interrupt_mutex);
286	}
287}
288EXPORT_SYMBOL_GPL(usbnet_status_stop);
289
290/* For suspend; always kill interrupt URB */
291static void __usbnet_status_stop_force(struct usbnet *dev)
292{
293	if (dev->interrupt) {
294		mutex_lock(&dev->interrupt_mutex);
295		usb_kill_urb(dev->interrupt);
296		dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
297		mutex_unlock(&dev->interrupt_mutex);
298	}
299}
300
301/* Passes this packet up the stack, updating its accounting.
302 * Some link protocols batch packets, so their rx_fixup paths
303 * can return clones as well as just modify the original skb.
304 */
305void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
306{
307	struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->stats64);
308	unsigned long flags;
309	int	status;
310
311	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
312		skb_queue_tail(&dev->rxq_pause, skb);
313		return;
314	}
315
316	/* only update if unset to allow minidriver rx_fixup override */
317	if (skb->protocol == 0)
318		skb->protocol = eth_type_trans (skb, dev->net);
319
320	flags = u64_stats_update_begin_irqsave(&stats64->syncp);
321	stats64->rx_packets++;
322	stats64->rx_bytes += skb->len;
323	u64_stats_update_end_irqrestore(&stats64->syncp, flags);
324
325	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
326		  skb->len + sizeof (struct ethhdr), skb->protocol);
327	memset (skb->cb, 0, sizeof (struct skb_data));
328
329	if (skb_defer_rx_timestamp(skb))
330		return;
331
332	status = netif_rx (skb);
333	if (status != NET_RX_SUCCESS)
334		netif_dbg(dev, rx_err, dev->net,
335			  "netif_rx status %d\n", status);
336}
337EXPORT_SYMBOL_GPL(usbnet_skb_return);
338
339/* must be called if hard_mtu or rx_urb_size changed */
340void usbnet_update_max_qlen(struct usbnet *dev)
341{
342	enum usb_device_speed speed = dev->udev->speed;
343
344	if (!dev->rx_urb_size || !dev->hard_mtu)
345		goto insanity;
346	switch (speed) {
347	case USB_SPEED_HIGH:
348		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
349		dev->tx_qlen = MAX_QUEUE_MEMORY / dev->hard_mtu;
350		break;
351	case USB_SPEED_SUPER:
352	case USB_SPEED_SUPER_PLUS:
353		/*
354		 * Not take default 5ms qlen for super speed HC to
355		 * save memory, and iperf tests show 2.5ms qlen can
356		 * work well
357		 */
358		dev->rx_qlen = 5 * MAX_QUEUE_MEMORY / dev->rx_urb_size;
359		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
360		break;
361	default:
362insanity:
363		dev->rx_qlen = dev->tx_qlen = 4;
364	}
365}
366EXPORT_SYMBOL_GPL(usbnet_update_max_qlen);
367
368
369/*-------------------------------------------------------------------------
370 *
371 * Network Device Driver (peer link to "Host Device", from USB host)
372 *
373 *-------------------------------------------------------------------------*/
374
375int usbnet_change_mtu (struct net_device *net, int new_mtu)
376{
377	struct usbnet	*dev = netdev_priv(net);
378	int		ll_mtu = new_mtu + net->hard_header_len;
379	int		old_hard_mtu = dev->hard_mtu;
380	int		old_rx_urb_size = dev->rx_urb_size;
381
382	// no second zero-length packet read wanted after mtu-sized packets
383	if ((ll_mtu % dev->maxpacket) == 0)
384		return -EDOM;
385	net->mtu = new_mtu;
386
387	dev->hard_mtu = net->mtu + net->hard_header_len;
388	if (dev->rx_urb_size == old_hard_mtu) {
389		dev->rx_urb_size = dev->hard_mtu;
390		if (dev->rx_urb_size > old_rx_urb_size) {
391			usbnet_pause_rx(dev);
392			usbnet_unlink_rx_urbs(dev);
393			usbnet_resume_rx(dev);
394		}
395	}
396
397	/* max qlen depend on hard_mtu and rx_urb_size */
398	usbnet_update_max_qlen(dev);
399
400	return 0;
401}
402EXPORT_SYMBOL_GPL(usbnet_change_mtu);
403
404/* The caller must hold list->lock */
405static void __usbnet_queue_skb(struct sk_buff_head *list,
406			struct sk_buff *newsk, enum skb_state state)
407{
408	struct skb_data *entry = (struct skb_data *) newsk->cb;
409
410	__skb_queue_tail(list, newsk);
411	entry->state = state;
412}
413
414/*-------------------------------------------------------------------------*/
415
416/* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
417 * completion callbacks.  2.5 should have fixed those bugs...
418 */
419
420static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
421		struct sk_buff_head *list, enum skb_state state)
422{
423	unsigned long		flags;
424	enum skb_state 		old_state;
425	struct skb_data *entry = (struct skb_data *) skb->cb;
426
427	spin_lock_irqsave(&list->lock, flags);
428	old_state = entry->state;
429	entry->state = state;
430	__skb_unlink(skb, list);
431
432	/* defer_bh() is never called with list == &dev->done.
433	 * spin_lock_nested() tells lockdep that it is OK to take
434	 * dev->done.lock here with list->lock held.
435	 */
436	spin_lock_nested(&dev->done.lock, SINGLE_DEPTH_NESTING);
437
438	__skb_queue_tail(&dev->done, skb);
439	if (dev->done.qlen == 1)
440		tasklet_schedule(&dev->bh);
441	spin_unlock(&dev->done.lock);
442	spin_unlock_irqrestore(&list->lock, flags);
443	return old_state;
444}
445
446/* some work can't be done in tasklets, so we use keventd
447 *
448 * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
449 * but tasklet_schedule() doesn't.  hope the failure is rare.
450 */
451void usbnet_defer_kevent (struct usbnet *dev, int work)
452{
453	set_bit (work, &dev->flags);
454	if (!schedule_work (&dev->kevent))
455		netdev_dbg(dev->net, "kevent %d may have been dropped\n", work);
456	else
457		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
458}
459EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
460
461/*-------------------------------------------------------------------------*/
462
463static void rx_complete (struct urb *urb);
464
465static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
466{
467	struct sk_buff		*skb;
468	struct skb_data		*entry;
469	int			retval = 0;
470	unsigned long		lockflags;
471	size_t			size = dev->rx_urb_size;
472
473	/* prevent rx skb allocation when error ratio is high */
474	if (test_bit(EVENT_RX_KILL, &dev->flags)) {
475		usb_free_urb(urb);
476		return -ENOLINK;
477	}
478
479	if (test_bit(EVENT_NO_IP_ALIGN, &dev->flags))
480		skb = __netdev_alloc_skb(dev->net, size, flags);
481	else
482		skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
483	if (!skb) {
484		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
485		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
486		usb_free_urb (urb);
487		return -ENOMEM;
488	}
489
490	entry = (struct skb_data *) skb->cb;
491	entry->urb = urb;
492	entry->dev = dev;
493	entry->length = 0;
494
495	usb_fill_bulk_urb (urb, dev->udev, dev->in,
496		skb->data, size, rx_complete, skb);
497
498	spin_lock_irqsave (&dev->rxq.lock, lockflags);
499
500	if (netif_running (dev->net) &&
501	    netif_device_present (dev->net) &&
502	    test_bit(EVENT_DEV_OPEN, &dev->flags) &&
503	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
504	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
505		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
506		case -EPIPE:
507			usbnet_defer_kevent (dev, EVENT_RX_HALT);
508			break;
509		case -ENOMEM:
510			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
511			break;
512		case -ENODEV:
513			netif_dbg(dev, ifdown, dev->net, "device gone\n");
514			netif_device_detach (dev->net);
515			break;
516		case -EHOSTUNREACH:
517			retval = -ENOLINK;
518			break;
519		default:
520			netif_dbg(dev, rx_err, dev->net,
521				  "rx submit, %d\n", retval);
522			tasklet_schedule (&dev->bh);
523			break;
524		case 0:
525			__usbnet_queue_skb(&dev->rxq, skb, rx_start);
526		}
527	} else {
528		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
529		retval = -ENOLINK;
530	}
531	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
532	if (retval) {
533		dev_kfree_skb_any (skb);
534		usb_free_urb (urb);
535	}
536	return retval;
537}
538
539
540/*-------------------------------------------------------------------------*/
541
542static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
543{
544	if (dev->driver_info->rx_fixup &&
545	    !dev->driver_info->rx_fixup (dev, skb)) {
546		/* With RX_ASSEMBLE, rx_fixup() must update counters */
547		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
548			dev->net->stats.rx_errors++;
549		goto done;
550	}
551	// else network stack removes extra byte if we forced a short packet
552
553	/* all data was already cloned from skb inside the driver */
554	if (dev->driver_info->flags & FLAG_MULTI_PACKET)
555		goto done;
556
557	if (skb->len < ETH_HLEN) {
558		dev->net->stats.rx_errors++;
559		dev->net->stats.rx_length_errors++;
560		netif_dbg(dev, rx_err, dev->net, "rx length %d\n", skb->len);
561	} else {
562		usbnet_skb_return(dev, skb);
563		return;
564	}
565
566done:
567	skb_queue_tail(&dev->done, skb);
568}
569
570/*-------------------------------------------------------------------------*/
571
572static void rx_complete (struct urb *urb)
573{
574	struct sk_buff		*skb = (struct sk_buff *) urb->context;
575	struct skb_data		*entry = (struct skb_data *) skb->cb;
576	struct usbnet		*dev = entry->dev;
577	int			urb_status = urb->status;
578	enum skb_state		state;
579
580	skb_put (skb, urb->actual_length);
581	state = rx_done;
582	entry->urb = NULL;
583
584	switch (urb_status) {
585	/* success */
586	case 0:
587		break;
588
589	/* stalls need manual reset. this is rare ... except that
590	 * when going through USB 2.0 TTs, unplug appears this way.
591	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
592	 * storm, recovering as needed.
593	 */
594	case -EPIPE:
595		dev->net->stats.rx_errors++;
596		usbnet_defer_kevent (dev, EVENT_RX_HALT);
597		fallthrough;
598
599	/* software-driven interface shutdown */
600	case -ECONNRESET:		/* async unlink */
601	case -ESHUTDOWN:		/* hardware gone */
602		netif_dbg(dev, ifdown, dev->net,
603			  "rx shutdown, code %d\n", urb_status);
604		goto block;
605
606	/* we get controller i/o faults during hub_wq disconnect() delays.
607	 * throttle down resubmits, to avoid log floods; just temporarily,
608	 * so we still recover when the fault isn't a hub_wq delay.
609	 */
610	case -EPROTO:
611	case -ETIME:
612	case -EILSEQ:
613		dev->net->stats.rx_errors++;
614		if (!timer_pending (&dev->delay)) {
615			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
616			netif_dbg(dev, link, dev->net,
617				  "rx throttle %d\n", urb_status);
618		}
619block:
620		state = rx_cleanup;
621		entry->urb = urb;
622		urb = NULL;
623		break;
624
625	/* data overrun ... flush fifo? */
626	case -EOVERFLOW:
627		dev->net->stats.rx_over_errors++;
628		fallthrough;
629
630	default:
631		state = rx_cleanup;
632		dev->net->stats.rx_errors++;
633		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
634		break;
635	}
636
637	/* stop rx if packet error rate is high */
638	if (++dev->pkt_cnt > 30) {
639		dev->pkt_cnt = 0;
640		dev->pkt_err = 0;
641	} else {
642		if (state == rx_cleanup)
643			dev->pkt_err++;
644		if (dev->pkt_err > 20)
645			set_bit(EVENT_RX_KILL, &dev->flags);
646	}
647
648	state = defer_bh(dev, skb, &dev->rxq, state);
649
650	if (urb) {
651		if (netif_running (dev->net) &&
652		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
653		    state != unlink_start) {
654			rx_submit (dev, urb, GFP_ATOMIC);
655			usb_mark_last_busy(dev->udev);
656			return;
657		}
658		usb_free_urb (urb);
659	}
660	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
661}
662
663/*-------------------------------------------------------------------------*/
664void usbnet_pause_rx(struct usbnet *dev)
665{
666	set_bit(EVENT_RX_PAUSED, &dev->flags);
667
668	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
669}
670EXPORT_SYMBOL_GPL(usbnet_pause_rx);
671
672void usbnet_resume_rx(struct usbnet *dev)
673{
674	struct sk_buff *skb;
675	int num = 0;
676
677	clear_bit(EVENT_RX_PAUSED, &dev->flags);
678
679	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
680		usbnet_skb_return(dev, skb);
681		num++;
682	}
683
684	tasklet_schedule(&dev->bh);
685
686	netif_dbg(dev, rx_status, dev->net,
687		  "paused rx queue disabled, %d skbs requeued\n", num);
688}
689EXPORT_SYMBOL_GPL(usbnet_resume_rx);
690
691void usbnet_purge_paused_rxq(struct usbnet *dev)
692{
693	skb_queue_purge(&dev->rxq_pause);
694}
695EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
696
697/*-------------------------------------------------------------------------*/
698
699// unlink pending rx/tx; completion handlers do all other cleanup
700
701static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
702{
703	unsigned long		flags;
704	struct sk_buff		*skb;
705	int			count = 0;
706
707	spin_lock_irqsave (&q->lock, flags);
708	while (!skb_queue_empty(q)) {
709		struct skb_data		*entry;
710		struct urb		*urb;
711		int			retval;
712
713		skb_queue_walk(q, skb) {
714			entry = (struct skb_data *) skb->cb;
715			if (entry->state != unlink_start)
716				goto found;
717		}
718		break;
719found:
720		entry->state = unlink_start;
721		urb = entry->urb;
722
723		/*
724		 * Get reference count of the URB to avoid it to be
725		 * freed during usb_unlink_urb, which may trigger
726		 * use-after-free problem inside usb_unlink_urb since
727		 * usb_unlink_urb is always racing with .complete
728		 * handler(include defer_bh).
729		 */
730		usb_get_urb(urb);
731		spin_unlock_irqrestore(&q->lock, flags);
732		// during some PM-driven resume scenarios,
733		// these (async) unlinks complete immediately
734		retval = usb_unlink_urb (urb);
735		if (retval != -EINPROGRESS && retval != 0)
736			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
737		else
738			count++;
739		usb_put_urb(urb);
740		spin_lock_irqsave(&q->lock, flags);
741	}
742	spin_unlock_irqrestore (&q->lock, flags);
743	return count;
744}
745
746// Flush all pending rx urbs
747// minidrivers may need to do this when the MTU changes
748
749void usbnet_unlink_rx_urbs(struct usbnet *dev)
750{
751	if (netif_running(dev->net)) {
752		(void) unlink_urbs (dev, &dev->rxq);
753		tasklet_schedule(&dev->bh);
754	}
755}
756EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
757
758/*-------------------------------------------------------------------------*/
759
760static void wait_skb_queue_empty(struct sk_buff_head *q)
761{
762	unsigned long flags;
763
764	spin_lock_irqsave(&q->lock, flags);
765	while (!skb_queue_empty(q)) {
766		spin_unlock_irqrestore(&q->lock, flags);
767		schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
768		set_current_state(TASK_UNINTERRUPTIBLE);
769		spin_lock_irqsave(&q->lock, flags);
770	}
771	spin_unlock_irqrestore(&q->lock, flags);
772}
773
774// precondition: never called in_interrupt
775static void usbnet_terminate_urbs(struct usbnet *dev)
776{
777	DECLARE_WAITQUEUE(wait, current);
778	int temp;
779
780	/* ensure there are no more active urbs */
781	add_wait_queue(&dev->wait, &wait);
782	set_current_state(TASK_UNINTERRUPTIBLE);
783	temp = unlink_urbs(dev, &dev->txq) +
784		unlink_urbs(dev, &dev->rxq);
785
786	/* maybe wait for deletions to finish. */
787	wait_skb_queue_empty(&dev->rxq);
788	wait_skb_queue_empty(&dev->txq);
789	wait_skb_queue_empty(&dev->done);
790	netif_dbg(dev, ifdown, dev->net,
791		  "waited for %d urb completions\n", temp);
792	set_current_state(TASK_RUNNING);
793	remove_wait_queue(&dev->wait, &wait);
794}
795
796int usbnet_stop (struct net_device *net)
797{
798	struct usbnet		*dev = netdev_priv(net);
799	const struct driver_info *info = dev->driver_info;
800	int			retval, pm, mpn;
801
802	clear_bit(EVENT_DEV_OPEN, &dev->flags);
803	netif_stop_queue (net);
804
805	netif_info(dev, ifdown, dev->net,
806		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
807		   net->stats.rx_packets, net->stats.tx_packets,
808		   net->stats.rx_errors, net->stats.tx_errors);
809
810	/* to not race resume */
811	pm = usb_autopm_get_interface(dev->intf);
812	/* allow minidriver to stop correctly (wireless devices to turn off
813	 * radio etc) */
814	if (info->stop) {
815		retval = info->stop(dev);
816		if (retval < 0)
817			netif_info(dev, ifdown, dev->net,
818				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
819				   retval,
820				   dev->udev->bus->bus_name, dev->udev->devpath,
821				   info->description);
822	}
823
824	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
825		usbnet_terminate_urbs(dev);
826
827	usbnet_status_stop(dev);
828
829	usbnet_purge_paused_rxq(dev);
830
831	mpn = !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
832
833	/* deferred work (timer, softirq, task) must also stop */
834	dev->flags = 0;
835	del_timer_sync (&dev->delay);
836	tasklet_kill (&dev->bh);
837	cancel_work_sync(&dev->kevent);
838	if (!pm)
839		usb_autopm_put_interface(dev->intf);
840
841	if (info->manage_power && mpn)
842		info->manage_power(dev, 0);
843	else
844		usb_autopm_put_interface(dev->intf);
845
846	return 0;
847}
848EXPORT_SYMBOL_GPL(usbnet_stop);
849
850/*-------------------------------------------------------------------------*/
851
852// posts reads, and enables write queuing
853
854// precondition: never called in_interrupt
855
856int usbnet_open (struct net_device *net)
857{
858	struct usbnet		*dev = netdev_priv(net);
859	int			retval;
860	const struct driver_info *info = dev->driver_info;
861
862	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
863		netif_info(dev, ifup, dev->net,
864			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
865			   retval,
866			   dev->udev->bus->bus_name,
867			   dev->udev->devpath,
868			   info->description);
869		goto done_nopm;
870	}
871
872	// put into "known safe" state
873	if (info->reset && (retval = info->reset (dev)) < 0) {
874		netif_info(dev, ifup, dev->net,
875			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
876			   retval,
877			   dev->udev->bus->bus_name,
878			   dev->udev->devpath,
879			   info->description);
880		goto done;
881	}
882
883	/* hard_mtu or rx_urb_size may change in reset() */
884	usbnet_update_max_qlen(dev);
885
886	// insist peer be connected
887	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
888		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
889		goto done;
890	}
891
892	/* start any status interrupt transfer */
893	if (dev->interrupt) {
894		retval = usbnet_status_start(dev, GFP_KERNEL);
895		if (retval < 0) {
896			netif_err(dev, ifup, dev->net,
897				  "intr submit %d\n", retval);
898			goto done;
899		}
900	}
901
902	set_bit(EVENT_DEV_OPEN, &dev->flags);
903	netif_start_queue (net);
904	netif_info(dev, ifup, dev->net,
905		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
906		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
907		   dev->net->mtu,
908		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
909		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
910		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
911		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
912		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
913		   "simple");
914
915	/* reset rx error state */
916	dev->pkt_cnt = 0;
917	dev->pkt_err = 0;
918	clear_bit(EVENT_RX_KILL, &dev->flags);
919
920	// delay posting reads until we're fully open
921	tasklet_schedule (&dev->bh);
922	if (info->manage_power) {
923		retval = info->manage_power(dev, 1);
924		if (retval < 0) {
925			retval = 0;
926			set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
927		} else {
928			usb_autopm_put_interface(dev->intf);
929		}
930	}
931	return retval;
932done:
933	usb_autopm_put_interface(dev->intf);
934done_nopm:
935	return retval;
936}
937EXPORT_SYMBOL_GPL(usbnet_open);
938
939/*-------------------------------------------------------------------------*/
940
941/* ethtool methods; minidrivers may need to add some more, but
942 * they'll probably want to use this base set.
943 */
944
945int usbnet_get_link_ksettings(struct net_device *net,
946			      struct ethtool_link_ksettings *cmd)
947{
948	struct usbnet *dev = netdev_priv(net);
949
950	if (!dev->mii.mdio_read)
951		return -EOPNOTSUPP;
952
953	mii_ethtool_get_link_ksettings(&dev->mii, cmd);
954
955	return 0;
956}
957EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings);
958
959int usbnet_set_link_ksettings(struct net_device *net,
960			      const struct ethtool_link_ksettings *cmd)
961{
962	struct usbnet *dev = netdev_priv(net);
963	int retval;
964
965	if (!dev->mii.mdio_write)
966		return -EOPNOTSUPP;
967
968	retval = mii_ethtool_set_link_ksettings(&dev->mii, cmd);
969
970	/* link speed/duplex might have changed */
971	if (dev->driver_info->link_reset)
972		dev->driver_info->link_reset(dev);
973
974	/* hard_mtu or rx_urb_size may change in link_reset() */
975	usbnet_update_max_qlen(dev);
976
977	return retval;
978}
979EXPORT_SYMBOL_GPL(usbnet_set_link_ksettings);
980
981void usbnet_get_stats64(struct net_device *net, struct rtnl_link_stats64 *stats)
982{
983	struct usbnet *dev = netdev_priv(net);
984
985	netdev_stats_to_stats64(stats, &net->stats);
986	dev_fetch_sw_netstats(stats, dev->stats64);
987}
988EXPORT_SYMBOL_GPL(usbnet_get_stats64);
989
990u32 usbnet_get_link (struct net_device *net)
991{
992	struct usbnet *dev = netdev_priv(net);
993
994	/* If a check_connect is defined, return its result */
995	if (dev->driver_info->check_connect)
996		return dev->driver_info->check_connect (dev) == 0;
997
998	/* if the device has mii operations, use those */
999	if (dev->mii.mdio_read)
1000		return mii_link_ok(&dev->mii);
1001
1002	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
1003	return ethtool_op_get_link(net);
1004}
1005EXPORT_SYMBOL_GPL(usbnet_get_link);
1006
1007int usbnet_nway_reset(struct net_device *net)
1008{
1009	struct usbnet *dev = netdev_priv(net);
1010
1011	if (!dev->mii.mdio_write)
1012		return -EOPNOTSUPP;
1013
1014	return mii_nway_restart(&dev->mii);
1015}
1016EXPORT_SYMBOL_GPL(usbnet_nway_reset);
1017
1018void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
1019{
1020	struct usbnet *dev = netdev_priv(net);
1021
1022	strlcpy (info->driver, dev->driver_name, sizeof info->driver);
1023	strlcpy (info->fw_version, dev->driver_info->description,
1024		sizeof info->fw_version);
1025	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
1026}
1027EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
1028
1029u32 usbnet_get_msglevel (struct net_device *net)
1030{
1031	struct usbnet *dev = netdev_priv(net);
1032
1033	return dev->msg_enable;
1034}
1035EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
1036
1037void usbnet_set_msglevel (struct net_device *net, u32 level)
1038{
1039	struct usbnet *dev = netdev_priv(net);
1040
1041	dev->msg_enable = level;
1042}
1043EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
1044
1045/* drivers may override default ethtool_ops in their bind() routine */
1046static const struct ethtool_ops usbnet_ethtool_ops = {
1047	.get_link		= usbnet_get_link,
1048	.nway_reset		= usbnet_nway_reset,
1049	.get_drvinfo		= usbnet_get_drvinfo,
1050	.get_msglevel		= usbnet_get_msglevel,
1051	.set_msglevel		= usbnet_set_msglevel,
1052	.get_ts_info		= ethtool_op_get_ts_info,
1053	.get_link_ksettings	= usbnet_get_link_ksettings,
1054	.set_link_ksettings	= usbnet_set_link_ksettings,
1055};
1056
1057/*-------------------------------------------------------------------------*/
1058
1059static void __handle_link_change(struct usbnet *dev)
1060{
1061	if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
1062		return;
1063
1064	if (!netif_carrier_ok(dev->net)) {
1065		/* kill URBs for reading packets to save bus bandwidth */
1066		unlink_urbs(dev, &dev->rxq);
1067
1068		/*
1069		 * tx_timeout will unlink URBs for sending packets and
1070		 * tx queue is stopped by netcore after link becomes off
1071		 */
1072	} else {
1073		/* submitting URBs for reading packets */
1074		tasklet_schedule(&dev->bh);
1075	}
1076
1077	/* hard_mtu or rx_urb_size may change during link change */
1078	usbnet_update_max_qlen(dev);
1079
1080	clear_bit(EVENT_LINK_CHANGE, &dev->flags);
1081}
1082
1083void usbnet_set_rx_mode(struct net_device *net)
1084{
1085	struct usbnet		*dev = netdev_priv(net);
1086
1087	usbnet_defer_kevent(dev, EVENT_SET_RX_MODE);
1088}
1089EXPORT_SYMBOL_GPL(usbnet_set_rx_mode);
1090
1091static void __handle_set_rx_mode(struct usbnet *dev)
1092{
1093	if (dev->driver_info->set_rx_mode)
1094		(dev->driver_info->set_rx_mode)(dev);
1095
1096	clear_bit(EVENT_SET_RX_MODE, &dev->flags);
1097}
1098
1099/* work that cannot be done in interrupt context uses keventd.
1100 *
1101 * NOTE:  with 2.5 we could do more of this using completion callbacks,
1102 * especially now that control transfers can be queued.
1103 */
1104static void
1105usbnet_deferred_kevent (struct work_struct *work)
1106{
1107	struct usbnet		*dev =
1108		container_of(work, struct usbnet, kevent);
1109	int			status;
1110
1111	/* usb_clear_halt() needs a thread context */
1112	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
1113		unlink_urbs (dev, &dev->txq);
1114		status = usb_autopm_get_interface(dev->intf);
1115		if (status < 0)
1116			goto fail_pipe;
1117		status = usb_clear_halt (dev->udev, dev->out);
1118		usb_autopm_put_interface(dev->intf);
1119		if (status < 0 &&
1120		    status != -EPIPE &&
1121		    status != -ESHUTDOWN) {
1122			if (netif_msg_tx_err (dev))
1123fail_pipe:
1124				netdev_err(dev->net, "can't clear tx halt, status %d\n",
1125					   status);
1126		} else {
1127			clear_bit (EVENT_TX_HALT, &dev->flags);
1128			if (status != -ESHUTDOWN)
1129				netif_wake_queue (dev->net);
1130		}
1131	}
1132	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
1133		unlink_urbs (dev, &dev->rxq);
1134		status = usb_autopm_get_interface(dev->intf);
1135		if (status < 0)
1136			goto fail_halt;
1137		status = usb_clear_halt (dev->udev, dev->in);
1138		usb_autopm_put_interface(dev->intf);
1139		if (status < 0 &&
1140		    status != -EPIPE &&
1141		    status != -ESHUTDOWN) {
1142			if (netif_msg_rx_err (dev))
1143fail_halt:
1144				netdev_err(dev->net, "can't clear rx halt, status %d\n",
1145					   status);
1146		} else {
1147			clear_bit (EVENT_RX_HALT, &dev->flags);
1148			tasklet_schedule (&dev->bh);
1149		}
1150	}
1151
1152	/* tasklet could resubmit itself forever if memory is tight */
1153	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
1154		struct urb	*urb = NULL;
1155		int resched = 1;
1156
1157		if (netif_running (dev->net))
1158			urb = usb_alloc_urb (0, GFP_KERNEL);
1159		else
1160			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1161		if (urb != NULL) {
1162			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1163			status = usb_autopm_get_interface(dev->intf);
1164			if (status < 0) {
1165				usb_free_urb(urb);
1166				goto fail_lowmem;
1167			}
1168			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
1169				resched = 0;
1170			usb_autopm_put_interface(dev->intf);
1171fail_lowmem:
1172			if (resched)
1173				tasklet_schedule (&dev->bh);
1174		}
1175	}
1176
1177	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
1178		const struct driver_info *info = dev->driver_info;
1179		int			retval = 0;
1180
1181		clear_bit (EVENT_LINK_RESET, &dev->flags);
1182		status = usb_autopm_get_interface(dev->intf);
1183		if (status < 0)
1184			goto skip_reset;
1185		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1186			usb_autopm_put_interface(dev->intf);
1187skip_reset:
1188			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1189				    retval,
1190				    dev->udev->bus->bus_name,
1191				    dev->udev->devpath,
1192				    info->description);
1193		} else {
1194			usb_autopm_put_interface(dev->intf);
1195		}
1196
1197		/* handle link change from link resetting */
1198		__handle_link_change(dev);
1199	}
1200
1201	if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
1202		__handle_link_change(dev);
1203
1204	if (test_bit (EVENT_SET_RX_MODE, &dev->flags))
1205		__handle_set_rx_mode(dev);
1206
1207
1208	if (dev->flags)
1209		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1210}
1211
1212/*-------------------------------------------------------------------------*/
1213
1214static void tx_complete (struct urb *urb)
1215{
1216	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1217	struct skb_data		*entry = (struct skb_data *) skb->cb;
1218	struct usbnet		*dev = entry->dev;
1219
1220	if (urb->status == 0) {
1221		struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->stats64);
1222		unsigned long flags;
1223
1224		flags = u64_stats_update_begin_irqsave(&stats64->syncp);
1225		stats64->tx_packets += entry->packets;
1226		stats64->tx_bytes += entry->length;
1227		u64_stats_update_end_irqrestore(&stats64->syncp, flags);
1228	} else {
1229		dev->net->stats.tx_errors++;
1230
1231		switch (urb->status) {
1232		case -EPIPE:
1233			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1234			break;
1235
1236		/* software-driven interface shutdown */
1237		case -ECONNRESET:		// async unlink
1238		case -ESHUTDOWN:		// hardware gone
1239			break;
1240
1241		/* like rx, tx gets controller i/o faults during hub_wq
1242		 * delays and so it uses the same throttling mechanism.
1243		 */
1244		case -EPROTO:
1245		case -ETIME:
1246		case -EILSEQ:
1247			usb_mark_last_busy(dev->udev);
1248			if (!timer_pending (&dev->delay)) {
1249				mod_timer (&dev->delay,
1250					jiffies + THROTTLE_JIFFIES);
1251				netif_dbg(dev, link, dev->net,
1252					  "tx throttle %d\n", urb->status);
1253			}
1254			netif_stop_queue (dev->net);
1255			break;
1256		default:
1257			netif_dbg(dev, tx_err, dev->net,
1258				  "tx err %d\n", entry->urb->status);
1259			break;
1260		}
1261	}
1262
1263	usb_autopm_put_interface_async(dev->intf);
1264	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1265}
1266
1267/*-------------------------------------------------------------------------*/
1268
1269void usbnet_tx_timeout (struct net_device *net, unsigned int txqueue)
1270{
1271	struct usbnet		*dev = netdev_priv(net);
1272
1273	unlink_urbs (dev, &dev->txq);
1274	tasklet_schedule (&dev->bh);
1275	/* this needs to be handled individually because the generic layer
1276	 * doesn't know what is sufficient and could not restore private
1277	 * information if a remedy of an unconditional reset were used.
1278	 */
1279	if (dev->driver_info->recover)
1280		(dev->driver_info->recover)(dev);
1281}
1282EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1283
1284/*-------------------------------------------------------------------------*/
1285
1286static int build_dma_sg(const struct sk_buff *skb, struct urb *urb)
1287{
1288	unsigned num_sgs, total_len = 0;
1289	int i, s = 0;
1290
1291	num_sgs = skb_shinfo(skb)->nr_frags + 1;
1292	if (num_sgs == 1)
1293		return 0;
1294
1295	/* reserve one for zero packet */
1296	urb->sg = kmalloc_array(num_sgs + 1, sizeof(struct scatterlist),
1297				GFP_ATOMIC);
1298	if (!urb->sg)
1299		return -ENOMEM;
1300
1301	urb->num_sgs = num_sgs;
1302	sg_init_table(urb->sg, urb->num_sgs + 1);
1303
1304	sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb));
1305	total_len += skb_headlen(skb);
1306
1307	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1308		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
1309
1310		total_len += skb_frag_size(f);
1311		sg_set_page(&urb->sg[i + s], skb_frag_page(f), skb_frag_size(f),
1312			    skb_frag_off(f));
1313	}
1314	urb->transfer_buffer_length = total_len;
1315
1316	return 1;
1317}
1318
1319netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1320				     struct net_device *net)
1321{
1322	struct usbnet		*dev = netdev_priv(net);
1323	unsigned int			length;
1324	struct urb		*urb = NULL;
1325	struct skb_data		*entry;
1326	const struct driver_info *info = dev->driver_info;
1327	unsigned long		flags;
1328	int retval;
1329
1330	if (skb)
1331		skb_tx_timestamp(skb);
1332
1333	// some devices want funky USB-level framing, for
1334	// win32 driver (usually) and/or hardware quirks
1335	if (info->tx_fixup) {
1336		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1337		if (!skb) {
1338			/* packet collected; minidriver waiting for more */
1339			if (info->flags & FLAG_MULTI_PACKET)
1340				goto not_drop;
1341			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1342			goto drop;
1343		}
1344	}
1345
1346	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1347		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1348		goto drop;
1349	}
1350
1351	entry = (struct skb_data *) skb->cb;
1352	entry->urb = urb;
1353	entry->dev = dev;
1354
1355	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1356			skb->data, skb->len, tx_complete, skb);
1357	if (dev->can_dma_sg) {
1358		if (build_dma_sg(skb, urb) < 0)
1359			goto drop;
1360	}
1361	length = urb->transfer_buffer_length;
1362
1363	/* don't assume the hardware handles USB_ZERO_PACKET
1364	 * NOTE:  strictly conforming cdc-ether devices should expect
1365	 * the ZLP here, but ignore the one-byte packet.
1366	 * NOTE2: CDC NCM specification is different from CDC ECM when
1367	 * handling ZLP/short packets, so cdc_ncm driver will make short
1368	 * packet itself if needed.
1369	 */
1370	if (length % dev->maxpacket == 0) {
1371		if (!(info->flags & FLAG_SEND_ZLP)) {
1372			if (!(info->flags & FLAG_MULTI_PACKET)) {
1373				length++;
1374				if (skb_tailroom(skb) && !urb->num_sgs) {
1375					skb->data[skb->len] = 0;
1376					__skb_put(skb, 1);
1377				} else if (urb->num_sgs)
1378					sg_set_buf(&urb->sg[urb->num_sgs++],
1379							dev->padding_pkt, 1);
1380			}
1381		} else
1382			urb->transfer_flags |= URB_ZERO_PACKET;
1383	}
1384	urb->transfer_buffer_length = length;
1385
1386	if (info->flags & FLAG_MULTI_PACKET) {
1387		/* Driver has set number of packets and a length delta.
1388		 * Calculate the complete length and ensure that it's
1389		 * positive.
1390		 */
1391		entry->length += length;
1392		if (WARN_ON_ONCE(entry->length <= 0))
1393			entry->length = length;
1394	} else {
1395		usbnet_set_skb_tx_stats(skb, 1, length);
1396	}
1397
1398	spin_lock_irqsave(&dev->txq.lock, flags);
1399	retval = usb_autopm_get_interface_async(dev->intf);
1400	if (retval < 0) {
1401		spin_unlock_irqrestore(&dev->txq.lock, flags);
1402		goto drop;
1403	}
1404	if (netif_queue_stopped(net)) {
1405		usb_autopm_put_interface_async(dev->intf);
1406		spin_unlock_irqrestore(&dev->txq.lock, flags);
1407		goto drop;
1408	}
1409
1410#ifdef CONFIG_PM
1411	/* if this triggers the device is still a sleep */
1412	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1413		/* transmission will be done in resume */
1414		usb_anchor_urb(urb, &dev->deferred);
1415		/* no use to process more packets */
1416		netif_stop_queue(net);
1417		usb_put_urb(urb);
1418		spin_unlock_irqrestore(&dev->txq.lock, flags);
1419		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1420		goto deferred;
1421	}
1422#endif
1423
1424	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1425	case -EPIPE:
1426		netif_stop_queue (net);
1427		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1428		usb_autopm_put_interface_async(dev->intf);
1429		break;
1430	default:
1431		usb_autopm_put_interface_async(dev->intf);
1432		netif_dbg(dev, tx_err, dev->net,
1433			  "tx: submit urb err %d\n", retval);
1434		break;
1435	case 0:
1436		netif_trans_update(net);
1437		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1438		if (dev->txq.qlen >= TX_QLEN (dev))
1439			netif_stop_queue (net);
1440	}
1441	spin_unlock_irqrestore (&dev->txq.lock, flags);
1442
1443	if (retval) {
1444		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1445drop:
1446		dev->net->stats.tx_dropped++;
1447not_drop:
1448		if (skb)
1449			dev_kfree_skb_any (skb);
1450		if (urb) {
1451			kfree(urb->sg);
1452			usb_free_urb(urb);
1453		}
1454	} else
1455		netif_dbg(dev, tx_queued, dev->net,
1456			  "> tx, len %u, type 0x%x\n", length, skb->protocol);
1457#ifdef CONFIG_PM
1458deferred:
1459#endif
1460	return NETDEV_TX_OK;
1461}
1462EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1463
1464static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1465{
1466	struct urb	*urb;
1467	int		i;
1468	int		ret = 0;
1469
1470	/* don't refill the queue all at once */
1471	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1472		urb = usb_alloc_urb(0, flags);
1473		if (urb != NULL) {
1474			ret = rx_submit(dev, urb, flags);
1475			if (ret)
1476				goto err;
1477		} else {
1478			ret = -ENOMEM;
1479			goto err;
1480		}
1481	}
1482err:
1483	return ret;
1484}
1485
1486/*-------------------------------------------------------------------------*/
1487
1488// tasklet (work deferred from completions, in_irq) or timer
1489
1490static void usbnet_bh (struct timer_list *t)
1491{
1492	struct usbnet		*dev = from_timer(dev, t, delay);
1493	struct sk_buff		*skb;
1494	struct skb_data		*entry;
1495
1496	while ((skb = skb_dequeue (&dev->done))) {
1497		entry = (struct skb_data *) skb->cb;
1498		switch (entry->state) {
1499		case rx_done:
1500			entry->state = rx_cleanup;
1501			rx_process (dev, skb);
1502			continue;
1503		case tx_done:
1504			kfree(entry->urb->sg);
1505			fallthrough;
1506		case rx_cleanup:
1507			usb_free_urb (entry->urb);
1508			dev_kfree_skb (skb);
1509			continue;
1510		default:
1511			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1512		}
1513	}
1514
1515	/* restart RX again after disabling due to high error rate */
1516	clear_bit(EVENT_RX_KILL, &dev->flags);
1517
1518	/* waiting for all pending urbs to complete?
1519	 * only then can we forgo submitting anew
1520	 */
1521	if (waitqueue_active(&dev->wait)) {
1522		if (dev->txq.qlen + dev->rxq.qlen + dev->done.qlen == 0)
1523			wake_up_all(&dev->wait);
1524
1525	// or are we maybe short a few urbs?
1526	} else if (netif_running (dev->net) &&
1527		   netif_device_present (dev->net) &&
1528		   netif_carrier_ok(dev->net) &&
1529		   !timer_pending(&dev->delay) &&
1530		   !test_bit(EVENT_RX_PAUSED, &dev->flags) &&
1531		   !test_bit(EVENT_RX_HALT, &dev->flags)) {
1532		int	temp = dev->rxq.qlen;
1533
1534		if (temp < RX_QLEN(dev)) {
1535			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1536				return;
1537			if (temp != dev->rxq.qlen)
1538				netif_dbg(dev, link, dev->net,
1539					  "rxqlen %d --> %d\n",
1540					  temp, dev->rxq.qlen);
1541			if (dev->rxq.qlen < RX_QLEN(dev))
1542				tasklet_schedule (&dev->bh);
1543		}
1544		if (dev->txq.qlen < TX_QLEN (dev))
1545			netif_wake_queue (dev->net);
1546	}
1547}
1548
1549static void usbnet_bh_tasklet(unsigned long data)
1550{
1551	struct timer_list *t = (struct timer_list *)data;
1552
1553	usbnet_bh(t);
1554}
1555
1556
1557/*-------------------------------------------------------------------------
1558 *
1559 * USB Device Driver support
1560 *
1561 *-------------------------------------------------------------------------*/
1562
1563// precondition: never called in_interrupt
1564
1565void usbnet_disconnect (struct usb_interface *intf)
1566{
1567	struct usbnet		*dev;
1568	struct usb_device	*xdev;
1569	struct net_device	*net;
1570	struct urb		*urb;
1571
1572	dev = usb_get_intfdata(intf);
1573	usb_set_intfdata(intf, NULL);
1574	if (!dev)
1575		return;
1576
1577	xdev = interface_to_usbdev (intf);
1578
1579	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1580		   intf->dev.driver->name,
1581		   xdev->bus->bus_name, xdev->devpath,
1582		   dev->driver_info->description);
1583
1584	net = dev->net;
1585	unregister_netdev (net);
1586
1587	while ((urb = usb_get_from_anchor(&dev->deferred))) {
1588		dev_kfree_skb(urb->context);
1589		kfree(urb->sg);
1590		usb_free_urb(urb);
1591	}
1592
1593	if (dev->driver_info->unbind)
1594		dev->driver_info->unbind (dev, intf);
1595
1596	usb_kill_urb(dev->interrupt);
1597	usb_free_urb(dev->interrupt);
1598	kfree(dev->padding_pkt);
1599
1600	free_percpu(dev->stats64);
1601	free_netdev(net);
1602}
1603EXPORT_SYMBOL_GPL(usbnet_disconnect);
1604
1605static const struct net_device_ops usbnet_netdev_ops = {
1606	.ndo_open		= usbnet_open,
1607	.ndo_stop		= usbnet_stop,
1608	.ndo_start_xmit		= usbnet_start_xmit,
1609	.ndo_tx_timeout		= usbnet_tx_timeout,
1610	.ndo_set_rx_mode	= usbnet_set_rx_mode,
1611	.ndo_change_mtu		= usbnet_change_mtu,
1612	.ndo_get_stats64	= usbnet_get_stats64,
1613	.ndo_set_mac_address 	= eth_mac_addr,
1614	.ndo_validate_addr	= eth_validate_addr,
1615};
1616
1617/*-------------------------------------------------------------------------*/
1618
1619// precondition: never called in_interrupt
1620
1621static struct device_type wlan_type = {
1622	.name	= "wlan",
1623};
1624
1625static struct device_type wwan_type = {
1626	.name	= "wwan",
1627};
1628
1629int
1630usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1631{
1632	struct usbnet			*dev;
1633	struct net_device		*net;
1634	struct usb_host_interface	*interface;
1635	const struct driver_info	*info;
1636	struct usb_device		*xdev;
1637	int				status;
1638	const char			*name;
1639	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1640
1641	/* usbnet already took usb runtime pm, so have to enable the feature
1642	 * for usb interface, otherwise usb_autopm_get_interface may return
1643	 * failure if RUNTIME_PM is enabled.
1644	 */
1645	if (!driver->supports_autosuspend) {
1646		driver->supports_autosuspend = 1;
1647		pm_runtime_enable(&udev->dev);
1648	}
1649
1650	name = udev->dev.driver->name;
1651	info = (const struct driver_info *) prod->driver_info;
1652	if (!info) {
1653		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1654		return -ENODEV;
1655	}
1656	xdev = interface_to_usbdev (udev);
1657	interface = udev->cur_altsetting;
1658
1659	status = -ENOMEM;
1660
1661	// set up our own records
1662	net = alloc_etherdev(sizeof(*dev));
1663	if (!net)
1664		goto out;
1665
1666	/* netdev_printk() needs this so do it as early as possible */
1667	SET_NETDEV_DEV(net, &udev->dev);
1668
1669	dev = netdev_priv(net);
1670	dev->udev = xdev;
1671	dev->intf = udev;
1672	dev->driver_info = info;
1673	dev->driver_name = name;
1674
1675	dev->stats64 = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1676	if (!dev->stats64)
1677		goto out0;
1678
1679	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1680				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1681	init_waitqueue_head(&dev->wait);
1682	skb_queue_head_init (&dev->rxq);
1683	skb_queue_head_init (&dev->txq);
1684	skb_queue_head_init (&dev->done);
1685	skb_queue_head_init(&dev->rxq_pause);
1686	dev->bh.func = usbnet_bh_tasklet;
1687	dev->bh.data = (unsigned long)&dev->delay;
1688	INIT_WORK (&dev->kevent, usbnet_deferred_kevent);
1689	init_usb_anchor(&dev->deferred);
1690	timer_setup(&dev->delay, usbnet_bh, 0);
1691	mutex_init (&dev->phy_mutex);
1692	mutex_init(&dev->interrupt_mutex);
1693	dev->interrupt_count = 0;
1694
1695	dev->net = net;
1696	strcpy (net->name, "usb%d");
1697	memcpy (net->dev_addr, node_id, sizeof node_id);
1698
1699	/* rx and tx sides can use different message sizes;
1700	 * bind() should set rx_urb_size in that case.
1701	 */
1702	dev->hard_mtu = net->mtu + net->hard_header_len;
1703	net->min_mtu = 0;
1704	net->max_mtu = ETH_MAX_MTU;
1705
1706	net->netdev_ops = &usbnet_netdev_ops;
1707	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1708	net->ethtool_ops = &usbnet_ethtool_ops;
1709
1710	// allow device-specific bind/init procedures
1711	// NOTE net->name still not usable ...
1712	if (info->bind) {
1713		status = info->bind (dev, udev);
1714		if (status < 0)
1715			goto out1;
1716
1717		// heuristic:  "usb%d" for links we know are two-host,
1718		// else "eth%d" when there's reasonable doubt.  userspace
1719		// can rename the link if it knows better.
1720		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1721		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1722		     (net->dev_addr [0] & 0x02) == 0))
1723			strcpy (net->name, "eth%d");
1724		/* WLAN devices should always be named "wlan%d" */
1725		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1726			strcpy(net->name, "wlan%d");
1727		/* WWAN devices should always be named "wwan%d" */
1728		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1729			strcpy(net->name, "wwan%d");
1730
1731		/* devices that cannot do ARP */
1732		if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1733			net->flags |= IFF_NOARP;
1734
1735		/* maybe the remote can't receive an Ethernet MTU */
1736		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1737			net->mtu = dev->hard_mtu - net->hard_header_len;
1738	} else if (!info->in || !info->out)
1739		status = usbnet_get_endpoints (dev, udev);
1740	else {
1741		u8 ep_addrs[3] = {
1742			info->in + USB_DIR_IN, info->out + USB_DIR_OUT, 0
1743		};
1744
1745		dev->in = usb_rcvbulkpipe (xdev, info->in);
1746		dev->out = usb_sndbulkpipe (xdev, info->out);
1747		if (!(info->flags & FLAG_NO_SETINT))
1748			status = usb_set_interface (xdev,
1749				interface->desc.bInterfaceNumber,
1750				interface->desc.bAlternateSetting);
1751		else
1752			status = 0;
1753
1754		if (status == 0 && !usb_check_bulk_endpoints(udev, ep_addrs))
1755			status = -EINVAL;
1756	}
1757	if (status >= 0 && dev->status)
1758		status = init_status (dev, udev);
1759	if (status < 0)
1760		goto out3;
1761
1762	if (!dev->rx_urb_size)
1763		dev->rx_urb_size = dev->hard_mtu;
1764	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1765	if (dev->maxpacket == 0) {
1766		/* that is a broken device */
1767		status = -ENODEV;
1768		goto out4;
1769	}
1770
1771	/* let userspace know we have a random address */
1772	if (ether_addr_equal(net->dev_addr, node_id))
1773		net->addr_assign_type = NET_ADDR_RANDOM;
1774
1775	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1776		SET_NETDEV_DEVTYPE(net, &wlan_type);
1777	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1778		SET_NETDEV_DEVTYPE(net, &wwan_type);
1779
1780	/* initialize max rx_qlen and tx_qlen */
1781	usbnet_update_max_qlen(dev);
1782
1783	if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&
1784		!(info->flags & FLAG_MULTI_PACKET)) {
1785		dev->padding_pkt = kzalloc(1, GFP_KERNEL);
1786		if (!dev->padding_pkt) {
1787			status = -ENOMEM;
1788			goto out4;
1789		}
1790	}
1791
1792	status = register_netdev (net);
1793	if (status)
1794		goto out5;
1795	netif_info(dev, probe, dev->net,
1796		   "register '%s' at usb-%s-%s, %s, %pM\n",
1797		   udev->dev.driver->name,
1798		   xdev->bus->bus_name, xdev->devpath,
1799		   dev->driver_info->description,
1800		   net->dev_addr);
1801
1802	// ok, it's ready to go.
1803	usb_set_intfdata (udev, dev);
1804
1805	netif_device_attach (net);
1806
1807	if (dev->driver_info->flags & FLAG_LINK_INTR)
1808		usbnet_link_change(dev, 0, 0);
1809
1810	return 0;
1811
1812out5:
1813	kfree(dev->padding_pkt);
1814out4:
1815	usb_free_urb(dev->interrupt);
1816out3:
1817	if (info->unbind)
1818		info->unbind (dev, udev);
1819out1:
1820	/* subdrivers must undo all they did in bind() if they
1821	 * fail it, but we may fail later and a deferred kevent
1822	 * may trigger an error resubmitting itself and, worse,
1823	 * schedule a timer. So we kill it all just in case.
1824	 */
1825	cancel_work_sync(&dev->kevent);
1826	del_timer_sync(&dev->delay);
1827	free_percpu(dev->stats64);
1828out0:
1829	free_netdev(net);
1830out:
1831	return status;
1832}
1833EXPORT_SYMBOL_GPL(usbnet_probe);
1834
1835/*-------------------------------------------------------------------------*/
1836
1837/*
1838 * suspend the whole driver as soon as the first interface is suspended
1839 * resume only when the last interface is resumed
1840 */
1841
1842int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1843{
1844	struct usbnet		*dev = usb_get_intfdata(intf);
1845
1846	if (!dev->suspend_count++) {
1847		spin_lock_irq(&dev->txq.lock);
1848		/* don't autosuspend while transmitting */
1849		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1850			dev->suspend_count--;
1851			spin_unlock_irq(&dev->txq.lock);
1852			return -EBUSY;
1853		} else {
1854			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1855			spin_unlock_irq(&dev->txq.lock);
1856		}
1857		/*
1858		 * accelerate emptying of the rx and queues, to avoid
1859		 * having everything error out.
1860		 */
1861		netif_device_detach (dev->net);
1862		usbnet_terminate_urbs(dev);
1863		__usbnet_status_stop_force(dev);
1864
1865		/*
1866		 * reattach so runtime management can use and
1867		 * wake the device
1868		 */
1869		netif_device_attach (dev->net);
1870	}
1871	return 0;
1872}
1873EXPORT_SYMBOL_GPL(usbnet_suspend);
1874
1875int usbnet_resume (struct usb_interface *intf)
1876{
1877	struct usbnet		*dev = usb_get_intfdata(intf);
1878	struct sk_buff          *skb;
1879	struct urb              *res;
1880	int                     retval;
1881
1882	if (!--dev->suspend_count) {
1883		/* resume interrupt URB if it was previously submitted */
1884		__usbnet_status_start_force(dev, GFP_NOIO);
1885
1886		spin_lock_irq(&dev->txq.lock);
1887		while ((res = usb_get_from_anchor(&dev->deferred))) {
1888
1889			skb = (struct sk_buff *)res->context;
1890			retval = usb_submit_urb(res, GFP_ATOMIC);
1891			if (retval < 0) {
1892				dev_kfree_skb_any(skb);
1893				kfree(res->sg);
1894				usb_free_urb(res);
1895				usb_autopm_put_interface_async(dev->intf);
1896			} else {
1897				netif_trans_update(dev->net);
1898				__skb_queue_tail(&dev->txq, skb);
1899			}
1900		}
1901
1902		smp_mb();
1903		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1904		spin_unlock_irq(&dev->txq.lock);
1905
1906		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1907			/* handle remote wakeup ASAP
1908			 * we cannot race against stop
1909			 */
1910			if (netif_device_present(dev->net) &&
1911				!timer_pending(&dev->delay) &&
1912				!test_bit(EVENT_RX_HALT, &dev->flags))
1913					rx_alloc_submit(dev, GFP_NOIO);
1914
1915			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1916				netif_tx_wake_all_queues(dev->net);
1917			tasklet_schedule (&dev->bh);
1918		}
1919	}
1920
1921	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1922		usb_autopm_get_interface_no_resume(intf);
1923
1924	return 0;
1925}
1926EXPORT_SYMBOL_GPL(usbnet_resume);
1927
1928/*
1929 * Either a subdriver implements manage_power, then it is assumed to always
1930 * be ready to be suspended or it reports the readiness to be suspended
1931 * explicitly
1932 */
1933void usbnet_device_suggests_idle(struct usbnet *dev)
1934{
1935	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1936		dev->intf->needs_remote_wakeup = 1;
1937		usb_autopm_put_interface_async(dev->intf);
1938	}
1939}
1940EXPORT_SYMBOL(usbnet_device_suggests_idle);
1941
1942/*
1943 * For devices that can do without special commands
1944 */
1945int usbnet_manage_power(struct usbnet *dev, int on)
1946{
1947	dev->intf->needs_remote_wakeup = on;
1948	return 0;
1949}
1950EXPORT_SYMBOL(usbnet_manage_power);
1951
1952void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
1953{
1954	/* update link after link is reseted */
1955	if (link && !need_reset)
1956		netif_carrier_on(dev->net);
1957	else
1958		netif_carrier_off(dev->net);
1959
1960	if (need_reset && link)
1961		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
1962	else
1963		usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
1964}
1965EXPORT_SYMBOL(usbnet_link_change);
1966
1967/*-------------------------------------------------------------------------*/
1968static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1969			     u16 value, u16 index, void *data, u16 size)
1970{
1971	void *buf = NULL;
1972	int err = -ENOMEM;
1973
1974	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
1975		   " value=0x%04x index=0x%04x size=%d\n",
1976		   cmd, reqtype, value, index, size);
1977
1978	if (size) {
1979		buf = kmalloc(size, GFP_NOIO);
1980		if (!buf)
1981			goto out;
1982	}
1983
1984	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
1985			      cmd, reqtype, value, index, buf, size,
1986			      USB_CTRL_GET_TIMEOUT);
1987	if (err > 0 && err <= size) {
1988        if (data)
1989            memcpy(data, buf, err);
1990        else
1991            netdev_dbg(dev->net,
1992                "Huh? Data requested but thrown away.\n");
1993    }
1994	kfree(buf);
1995out:
1996	return err;
1997}
1998
1999static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2000			      u16 value, u16 index, const void *data,
2001			      u16 size)
2002{
2003	void *buf = NULL;
2004	int err = -ENOMEM;
2005
2006	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2007		   " value=0x%04x index=0x%04x size=%d\n",
2008		   cmd, reqtype, value, index, size);
2009
2010	if (data) {
2011		buf = kmemdup(data, size, GFP_NOIO);
2012		if (!buf)
2013			goto out;
2014	} else {
2015        if (size) {
2016            WARN_ON_ONCE(1);
2017            err = -EINVAL;
2018            goto out;
2019        }
2020    }
2021
2022	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
2023			      cmd, reqtype, value, index, buf, size,
2024			      USB_CTRL_SET_TIMEOUT);
2025	kfree(buf);
2026
2027out:
2028	return err;
2029}
2030
2031/*
2032 * The function can't be called inside suspend/resume callback,
2033 * otherwise deadlock will be caused.
2034 */
2035int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2036		    u16 value, u16 index, void *data, u16 size)
2037{
2038	int ret;
2039
2040	if (usb_autopm_get_interface(dev->intf) < 0)
2041		return -ENODEV;
2042	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2043				data, size);
2044	usb_autopm_put_interface(dev->intf);
2045	return ret;
2046}
2047EXPORT_SYMBOL_GPL(usbnet_read_cmd);
2048
2049/*
2050 * The function can't be called inside suspend/resume callback,
2051 * otherwise deadlock will be caused.
2052 */
2053int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2054		     u16 value, u16 index, const void *data, u16 size)
2055{
2056	int ret;
2057
2058	if (usb_autopm_get_interface(dev->intf) < 0)
2059		return -ENODEV;
2060	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2061				 data, size);
2062	usb_autopm_put_interface(dev->intf);
2063	return ret;
2064}
2065EXPORT_SYMBOL_GPL(usbnet_write_cmd);
2066
2067/*
2068 * The function can be called inside suspend/resume callback safely
2069 * and should only be called by suspend/resume callback generally.
2070 */
2071int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2072			  u16 value, u16 index, void *data, u16 size)
2073{
2074	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2075				 data, size);
2076}
2077EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
2078
2079/*
2080 * The function can be called inside suspend/resume callback safely
2081 * and should only be called by suspend/resume callback generally.
2082 */
2083int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2084			  u16 value, u16 index, const void *data,
2085			  u16 size)
2086{
2087	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2088				  data, size);
2089}
2090EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
2091
2092static void usbnet_async_cmd_cb(struct urb *urb)
2093{
2094	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
2095	int status = urb->status;
2096
2097	if (status < 0)
2098		dev_dbg(&urb->dev->dev, "%s failed with %d",
2099			__func__, status);
2100
2101	kfree(req);
2102	usb_free_urb(urb);
2103}
2104
2105/*
2106 * The caller must make sure that device can't be put into suspend
2107 * state until the control URB completes.
2108 */
2109int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
2110			   u16 value, u16 index, const void *data, u16 size)
2111{
2112	struct usb_ctrlrequest *req;
2113	struct urb *urb;
2114	int err = -ENOMEM;
2115	void *buf = NULL;
2116
2117	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2118		   " value=0x%04x index=0x%04x size=%d\n",
2119		   cmd, reqtype, value, index, size);
2120
2121	urb = usb_alloc_urb(0, GFP_ATOMIC);
2122	if (!urb)
2123		goto fail;
2124
2125	if (data) {
2126		buf = kmemdup(data, size, GFP_ATOMIC);
2127		if (!buf) {
2128			netdev_err(dev->net, "Error allocating buffer"
2129				   " in %s!\n", __func__);
2130			goto fail_free_urb;
2131		}
2132	}
2133
2134	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
2135	if (!req)
2136		goto fail_free_buf;
2137
2138	req->bRequestType = reqtype;
2139	req->bRequest = cmd;
2140	req->wValue = cpu_to_le16(value);
2141	req->wIndex = cpu_to_le16(index);
2142	req->wLength = cpu_to_le16(size);
2143
2144	usb_fill_control_urb(urb, dev->udev,
2145			     usb_sndctrlpipe(dev->udev, 0),
2146			     (void *)req, buf, size,
2147			     usbnet_async_cmd_cb, req);
2148	urb->transfer_flags |= URB_FREE_BUFFER;
2149
2150	err = usb_submit_urb(urb, GFP_ATOMIC);
2151	if (err < 0) {
2152		netdev_err(dev->net, "Error submitting the control"
2153			   " message: status=%d\n", err);
2154		goto fail_free_all;
2155	}
2156	return 0;
2157
2158fail_free_all:
2159	kfree(req);
2160fail_free_buf:
2161	kfree(buf);
2162	/*
2163	 * avoid a double free
2164	 * needed because the flag can be set only
2165	 * after filling the URB
2166	 */
2167	urb->transfer_flags = 0;
2168fail_free_urb:
2169	usb_free_urb(urb);
2170fail:
2171	return err;
2172
2173}
2174EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
2175/*-------------------------------------------------------------------------*/
2176
2177static int __init usbnet_init(void)
2178{
2179	/* Compiler should optimize this out. */
2180	BUILD_BUG_ON(
2181		sizeof_field(struct sk_buff, cb) < sizeof(struct skb_data));
2182
2183	eth_random_addr(node_id);
2184	return 0;
2185}
2186module_init(usbnet_init);
2187
2188static void __exit usbnet_exit(void)
2189{
2190}
2191module_exit(usbnet_exit);
2192
2193MODULE_AUTHOR("David Brownell");
2194MODULE_DESCRIPTION("USB network driver framework");
2195MODULE_LICENSE("GPL");
2196