Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6
[linux-2.6.git] / drivers / net / usb / usbnet.c
1 /*
2  * USB Network driver infrastructure
3  * Copyright (C) 2000-2005 by David Brownell
4  * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19  */
20
21 /*
22  * This is a generic "USB networking" framework that works with several
23  * kinds of full and high speed networking devices:  host-to-host cables,
24  * smart usb peripherals, and actual Ethernet adapters.
25  *
26  * These devices usually differ in terms of control protocols (if they
27  * even have one!) and sometimes they define new framing to wrap or batch
28  * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
29  * so interface (un)binding, endpoint I/O queues, fault handling, and other
30  * issues can usefully be addressed by this framework.
31  */
32
33 // #define      DEBUG                   // error path messages, extra info
34 // #define      VERBOSE                 // more; success messages
35
36 #include <linux/module.h>
37 #include <linux/init.h>
38 #include <linux/netdevice.h>
39 #include <linux/etherdevice.h>
40 #include <linux/ctype.h>
41 #include <linux/ethtool.h>
42 #include <linux/workqueue.h>
43 #include <linux/mii.h>
44 #include <linux/usb.h>
45 #include <linux/usb/usbnet.h>
46
47 #define DRIVER_VERSION          "22-Aug-2005"
48
49
50 /*-------------------------------------------------------------------------*/
51
52 /*
53  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
54  * Several dozen bytes of IPv4 data can fit in two such transactions.
55  * One maximum size Ethernet packet takes twenty four of them.
56  * For high speed, each frame comfortably fits almost 36 max size
57  * Ethernet packets (so queues should be bigger).
58  *
59  * REVISIT qlens should be members of 'struct usbnet'; the goal is to
60  * let the USB host controller be busy for 5msec or more before an irq
61  * is required, under load.  Jumbograms change the equation.
62  */
63 #define RX_MAX_QUEUE_MEMORY (60 * 1518)
64 #define RX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
65                         (RX_MAX_QUEUE_MEMORY/(dev)->rx_urb_size) : 4)
66 #define TX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
67                         (RX_MAX_QUEUE_MEMORY/(dev)->hard_mtu) : 4)
68
69 // reawaken network queue this soon after stopping; else watchdog barks
70 #define TX_TIMEOUT_JIFFIES      (5*HZ)
71
72 // throttle rx/tx briefly after some faults, so khubd might disconnect()
73 // us (it polls at HZ/4 usually) before we report too many false errors.
74 #define THROTTLE_JIFFIES        (HZ/8)
75
76 // between wakeups
77 #define UNLINK_TIMEOUT_MS       3
78
79 /*-------------------------------------------------------------------------*/
80
81 // randomly generated ethernet address
82 static u8       node_id [ETH_ALEN];
83
84 static const char driver_name [] = "usbnet";
85
86 /* use ethtool to change the level for any given device */
87 static int msg_level = -1;
88 module_param (msg_level, int, 0);
89 MODULE_PARM_DESC (msg_level, "Override default message level");
90
91 /*-------------------------------------------------------------------------*/
92
93 /* handles CDC Ethernet and many other network "bulk data" interfaces */
94 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
95 {
96         int                             tmp;
97         struct usb_host_interface       *alt = NULL;
98         struct usb_host_endpoint        *in = NULL, *out = NULL;
99         struct usb_host_endpoint        *status = NULL;
100
101         for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
102                 unsigned        ep;
103
104                 in = out = status = NULL;
105                 alt = intf->altsetting + tmp;
106
107                 /* take the first altsetting with in-bulk + out-bulk;
108                  * remember any status endpoint, just in case;
109                  * ignore other endpoints and altsetttings.
110                  */
111                 for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
112                         struct usb_host_endpoint        *e;
113                         int                             intr = 0;
114
115                         e = alt->endpoint + ep;
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
160 static u8 nibble(unsigned char c)
161 {
162         if (likely(isdigit(c)))
163                 return c - '0';
164         c = toupper(c);
165         if (likely(isxdigit(c)))
166                 return 10 + c - 'A';
167         return 0;
168 }
169
170 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
171 {
172         int             tmp, i;
173         unsigned char   buf [13];
174
175         tmp = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
176         if (tmp != 12) {
177                 dev_dbg(&dev->udev->dev,
178                         "bad MAC string %d fetch, %d\n", iMACAddress, tmp);
179                 if (tmp >= 0)
180                         tmp = -EINVAL;
181                 return tmp;
182         }
183         for (i = tmp = 0; i < 6; i++, tmp += 2)
184                 dev->net->dev_addr [i] =
185                         (nibble(buf [tmp]) << 4) + nibble(buf [tmp + 1]);
186         return 0;
187 }
188 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
189
190 static void intr_complete (struct urb *urb);
191
192 static int init_status (struct usbnet *dev, struct usb_interface *intf)
193 {
194         char            *buf = NULL;
195         unsigned        pipe = 0;
196         unsigned        maxp;
197         unsigned        period;
198
199         if (!dev->driver_info->status)
200                 return 0;
201
202         pipe = usb_rcvintpipe (dev->udev,
203                         dev->status->desc.bEndpointAddress
204                                 & USB_ENDPOINT_NUMBER_MASK);
205         maxp = usb_maxpacket (dev->udev, pipe, 0);
206
207         /* avoid 1 msec chatter:  min 8 msec poll rate */
208         period = max ((int) dev->status->desc.bInterval,
209                 (dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
210
211         buf = kmalloc (maxp, GFP_KERNEL);
212         if (buf) {
213                 dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
214                 if (!dev->interrupt) {
215                         kfree (buf);
216                         return -ENOMEM;
217                 } else {
218                         usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
219                                 buf, maxp, intr_complete, dev, period);
220                         dev_dbg(&intf->dev,
221                                 "status ep%din, %d bytes period %d\n",
222                                 usb_pipeendpoint(pipe), maxp, period);
223                 }
224         }
225         return 0;
226 }
227
228 /* Passes this packet up the stack, updating its accounting.
229  * Some link protocols batch packets, so their rx_fixup paths
230  * can return clones as well as just modify the original skb.
231  */
232 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
233 {
234         int     status;
235
236         skb->protocol = eth_type_trans (skb, dev->net);
237         dev->stats.rx_packets++;
238         dev->stats.rx_bytes += skb->len;
239
240         if (netif_msg_rx_status (dev))
241                 devdbg (dev, "< rx, len %zu, type 0x%x",
242                         skb->len + sizeof (struct ethhdr), skb->protocol);
243         memset (skb->cb, 0, sizeof (struct skb_data));
244         status = netif_rx (skb);
245         if (status != NET_RX_SUCCESS && netif_msg_rx_err (dev))
246                 devdbg (dev, "netif_rx status %d", status);
247 }
248 EXPORT_SYMBOL_GPL(usbnet_skb_return);
249
250 \f
251 /*-------------------------------------------------------------------------
252  *
253  * Network Device Driver (peer link to "Host Device", from USB host)
254  *
255  *-------------------------------------------------------------------------*/
256
257 int usbnet_change_mtu (struct net_device *net, int new_mtu)
258 {
259         struct usbnet   *dev = netdev_priv(net);
260         int             ll_mtu = new_mtu + net->hard_header_len;
261         int             old_hard_mtu = dev->hard_mtu;
262         int             old_rx_urb_size = dev->rx_urb_size;
263
264         if (new_mtu <= 0)
265                 return -EINVAL;
266         // no second zero-length packet read wanted after mtu-sized packets
267         if ((ll_mtu % dev->maxpacket) == 0)
268                 return -EDOM;
269         net->mtu = new_mtu;
270
271         dev->hard_mtu = net->mtu + net->hard_header_len;
272         if (dev->rx_urb_size == old_hard_mtu) {
273                 dev->rx_urb_size = dev->hard_mtu;
274                 if (dev->rx_urb_size > old_rx_urb_size)
275                         usbnet_unlink_rx_urbs(dev);
276         }
277
278         return 0;
279 }
280 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
281
282 /*-------------------------------------------------------------------------*/
283
284 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
285  * completion callbacks.  2.5 should have fixed those bugs...
286  */
287
288 static void defer_bh(struct usbnet *dev, struct sk_buff *skb, struct sk_buff_head *list)
289 {
290         unsigned long           flags;
291
292         spin_lock_irqsave(&list->lock, flags);
293         __skb_unlink(skb, list);
294         spin_unlock(&list->lock);
295         spin_lock(&dev->done.lock);
296         __skb_queue_tail(&dev->done, skb);
297         if (dev->done.qlen == 1)
298                 tasklet_schedule(&dev->bh);
299         spin_unlock_irqrestore(&dev->done.lock, flags);
300 }
301
302 /* some work can't be done in tasklets, so we use keventd
303  *
304  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
305  * but tasklet_schedule() doesn't.  hope the failure is rare.
306  */
307 void usbnet_defer_kevent (struct usbnet *dev, int work)
308 {
309         set_bit (work, &dev->flags);
310         if (!schedule_work (&dev->kevent))
311                 deverr (dev, "kevent %d may have been dropped", work);
312         else
313                 devdbg (dev, "kevent %d scheduled", work);
314 }
315 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
316
317 /*-------------------------------------------------------------------------*/
318
319 static void rx_complete (struct urb *urb);
320
321 static void rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
322 {
323         struct sk_buff          *skb;
324         struct skb_data         *entry;
325         int                     retval = 0;
326         unsigned long           lockflags;
327         size_t                  size = dev->rx_urb_size;
328
329         if ((skb = alloc_skb (size + NET_IP_ALIGN, flags)) == NULL) {
330                 if (netif_msg_rx_err (dev))
331                         devdbg (dev, "no rx skb");
332                 usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
333                 usb_free_urb (urb);
334                 return;
335         }
336         skb_reserve (skb, NET_IP_ALIGN);
337
338         entry = (struct skb_data *) skb->cb;
339         entry->urb = urb;
340         entry->dev = dev;
341         entry->state = rx_start;
342         entry->length = 0;
343
344         usb_fill_bulk_urb (urb, dev->udev, dev->in,
345                 skb->data, size, rx_complete, skb);
346
347         spin_lock_irqsave (&dev->rxq.lock, lockflags);
348
349         if (netif_running (dev->net)
350                         && netif_device_present (dev->net)
351                         && !test_bit (EVENT_RX_HALT, &dev->flags)) {
352                 switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
353                 case -EPIPE:
354                         usbnet_defer_kevent (dev, EVENT_RX_HALT);
355                         break;
356                 case -ENOMEM:
357                         usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
358                         break;
359                 case -ENODEV:
360                         if (netif_msg_ifdown (dev))
361                                 devdbg (dev, "device gone");
362                         netif_device_detach (dev->net);
363                         break;
364                 default:
365                         if (netif_msg_rx_err (dev))
366                                 devdbg (dev, "rx submit, %d", retval);
367                         tasklet_schedule (&dev->bh);
368                         break;
369                 case 0:
370                         __skb_queue_tail (&dev->rxq, skb);
371                 }
372         } else {
373                 if (netif_msg_ifdown (dev))
374                         devdbg (dev, "rx: stopped");
375                 retval = -ENOLINK;
376         }
377         spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
378         if (retval) {
379                 dev_kfree_skb_any (skb);
380                 usb_free_urb (urb);
381         }
382 }
383
384
385 /*-------------------------------------------------------------------------*/
386
387 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
388 {
389         if (dev->driver_info->rx_fixup
390                         && !dev->driver_info->rx_fixup (dev, skb))
391                 goto error;
392         // else network stack removes extra byte if we forced a short packet
393
394         if (skb->len)
395                 usbnet_skb_return (dev, skb);
396         else {
397                 if (netif_msg_rx_err (dev))
398                         devdbg (dev, "drop");
399 error:
400                 dev->stats.rx_errors++;
401                 skb_queue_tail (&dev->done, skb);
402         }
403 }
404
405 /*-------------------------------------------------------------------------*/
406
407 static void rx_complete (struct urb *urb)
408 {
409         struct sk_buff          *skb = (struct sk_buff *) urb->context;
410         struct skb_data         *entry = (struct skb_data *) skb->cb;
411         struct usbnet           *dev = entry->dev;
412         int                     urb_status = urb->status;
413
414         skb_put (skb, urb->actual_length);
415         entry->state = rx_done;
416         entry->urb = NULL;
417
418         switch (urb_status) {
419         /* success */
420         case 0:
421                 if (skb->len < dev->net->hard_header_len) {
422                         entry->state = rx_cleanup;
423                         dev->stats.rx_errors++;
424                         dev->stats.rx_length_errors++;
425                         if (netif_msg_rx_err (dev))
426                                 devdbg (dev, "rx length %d", skb->len);
427                 }
428                 break;
429
430         /* stalls need manual reset. this is rare ... except that
431          * when going through USB 2.0 TTs, unplug appears this way.
432          * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
433          * storm, recovering as needed.
434          */
435         case -EPIPE:
436                 dev->stats.rx_errors++;
437                 usbnet_defer_kevent (dev, EVENT_RX_HALT);
438                 // FALLTHROUGH
439
440         /* software-driven interface shutdown */
441         case -ECONNRESET:               /* async unlink */
442         case -ESHUTDOWN:                /* hardware gone */
443                 if (netif_msg_ifdown (dev))
444                         devdbg (dev, "rx shutdown, code %d", urb_status);
445                 goto block;
446
447         /* we get controller i/o faults during khubd disconnect() delays.
448          * throttle down resubmits, to avoid log floods; just temporarily,
449          * so we still recover when the fault isn't a khubd delay.
450          */
451         case -EPROTO:
452         case -ETIME:
453         case -EILSEQ:
454                 dev->stats.rx_errors++;
455                 if (!timer_pending (&dev->delay)) {
456                         mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
457                         if (netif_msg_link (dev))
458                                 devdbg (dev, "rx throttle %d", urb_status);
459                 }
460 block:
461                 entry->state = rx_cleanup;
462                 entry->urb = urb;
463                 urb = NULL;
464                 break;
465
466         /* data overrun ... flush fifo? */
467         case -EOVERFLOW:
468                 dev->stats.rx_over_errors++;
469                 // FALLTHROUGH
470
471         default:
472                 entry->state = rx_cleanup;
473                 dev->stats.rx_errors++;
474                 if (netif_msg_rx_err (dev))
475                         devdbg (dev, "rx status %d", urb_status);
476                 break;
477         }
478
479         defer_bh(dev, skb, &dev->rxq);
480
481         if (urb) {
482                 if (netif_running (dev->net)
483                                 && !test_bit (EVENT_RX_HALT, &dev->flags)) {
484                         rx_submit (dev, urb, GFP_ATOMIC);
485                         return;
486                 }
487                 usb_free_urb (urb);
488         }
489         if (netif_msg_rx_err (dev))
490                 devdbg (dev, "no read resubmitted");
491 }
492
493 static void intr_complete (struct urb *urb)
494 {
495         struct usbnet   *dev = urb->context;
496         int             status = urb->status;
497
498         switch (status) {
499         /* success */
500         case 0:
501                 dev->driver_info->status(dev, urb);
502                 break;
503
504         /* software-driven interface shutdown */
505         case -ENOENT:           /* urb killed */
506         case -ESHUTDOWN:        /* hardware gone */
507                 if (netif_msg_ifdown (dev))
508                         devdbg (dev, "intr shutdown, code %d", status);
509                 return;
510
511         /* NOTE:  not throttling like RX/TX, since this endpoint
512          * already polls infrequently
513          */
514         default:
515                 devdbg (dev, "intr status %d", status);
516                 break;
517         }
518
519         if (!netif_running (dev->net))
520                 return;
521
522         memset(urb->transfer_buffer, 0, urb->transfer_buffer_length);
523         status = usb_submit_urb (urb, GFP_ATOMIC);
524         if (status != 0 && netif_msg_timer (dev))
525                 deverr(dev, "intr resubmit --> %d", status);
526 }
527
528 /*-------------------------------------------------------------------------*/
529
530 // unlink pending rx/tx; completion handlers do all other cleanup
531
532 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
533 {
534         unsigned long           flags;
535         struct sk_buff          *skb, *skbnext;
536         int                     count = 0;
537
538         spin_lock_irqsave (&q->lock, flags);
539         skb_queue_walk_safe(q, skb, skbnext) {
540                 struct skb_data         *entry;
541                 struct urb              *urb;
542                 int                     retval;
543
544                 entry = (struct skb_data *) skb->cb;
545                 urb = entry->urb;
546
547                 // during some PM-driven resume scenarios,
548                 // these (async) unlinks complete immediately
549                 retval = usb_unlink_urb (urb);
550                 if (retval != -EINPROGRESS && retval != 0)
551                         devdbg (dev, "unlink urb err, %d", retval);
552                 else
553                         count++;
554         }
555         spin_unlock_irqrestore (&q->lock, flags);
556         return count;
557 }
558
559 // Flush all pending rx urbs
560 // minidrivers may need to do this when the MTU changes
561
562 void usbnet_unlink_rx_urbs(struct usbnet *dev)
563 {
564         if (netif_running(dev->net)) {
565                 (void) unlink_urbs (dev, &dev->rxq);
566                 tasklet_schedule(&dev->bh);
567         }
568 }
569 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
570
571 /*-------------------------------------------------------------------------*/
572
573 // precondition: never called in_interrupt
574
575 int usbnet_stop (struct net_device *net)
576 {
577         struct usbnet           *dev = netdev_priv(net);
578         int                     temp;
579         DECLARE_WAIT_QUEUE_HEAD_ONSTACK (unlink_wakeup);
580         DECLARE_WAITQUEUE (wait, current);
581
582         netif_stop_queue (net);
583
584         if (netif_msg_ifdown (dev))
585                 devinfo (dev, "stop stats: rx/tx %ld/%ld, errs %ld/%ld",
586                         dev->stats.rx_packets, dev->stats.tx_packets,
587                         dev->stats.rx_errors, dev->stats.tx_errors
588                         );
589
590         // ensure there are no more active urbs
591         add_wait_queue (&unlink_wakeup, &wait);
592         dev->wait = &unlink_wakeup;
593         temp = unlink_urbs (dev, &dev->txq) + unlink_urbs (dev, &dev->rxq);
594
595         // maybe wait for deletions to finish.
596         while (!skb_queue_empty(&dev->rxq)
597                         && !skb_queue_empty(&dev->txq)
598                         && !skb_queue_empty(&dev->done)) {
599                 msleep(UNLINK_TIMEOUT_MS);
600                 if (netif_msg_ifdown (dev))
601                         devdbg (dev, "waited for %d urb completions", temp);
602         }
603         dev->wait = NULL;
604         remove_wait_queue (&unlink_wakeup, &wait);
605
606         usb_kill_urb(dev->interrupt);
607
608         /* deferred work (task, timer, softirq) must also stop.
609          * can't flush_scheduled_work() until we drop rtnl (later),
610          * else workers could deadlock; so make workers a NOP.
611          */
612         dev->flags = 0;
613         del_timer_sync (&dev->delay);
614         tasklet_kill (&dev->bh);
615         usb_autopm_put_interface(dev->intf);
616
617         return 0;
618 }
619 EXPORT_SYMBOL_GPL(usbnet_stop);
620
621 /*-------------------------------------------------------------------------*/
622
623 // posts reads, and enables write queuing
624
625 // precondition: never called in_interrupt
626
627 int usbnet_open (struct net_device *net)
628 {
629         struct usbnet           *dev = netdev_priv(net);
630         int                     retval;
631         struct driver_info      *info = dev->driver_info;
632
633         if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
634                 if (netif_msg_ifup (dev))
635                         devinfo (dev,
636                                 "resumption fail (%d) usbnet usb-%s-%s, %s",
637                                 retval,
638                                 dev->udev->bus->bus_name, dev->udev->devpath,
639                         info->description);
640                 goto done_nopm;
641         }
642
643         // put into "known safe" state
644         if (info->reset && (retval = info->reset (dev)) < 0) {
645                 if (netif_msg_ifup (dev))
646                         devinfo (dev,
647                                 "open reset fail (%d) usbnet usb-%s-%s, %s",
648                                 retval,
649                                 dev->udev->bus->bus_name, dev->udev->devpath,
650                         info->description);
651                 goto done;
652         }
653
654         // insist peer be connected
655         if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
656                 if (netif_msg_ifup (dev))
657                         devdbg (dev, "can't open; %d", retval);
658                 goto done;
659         }
660
661         /* start any status interrupt transfer */
662         if (dev->interrupt) {
663                 retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
664                 if (retval < 0) {
665                         if (netif_msg_ifup (dev))
666                                 deverr (dev, "intr submit %d", retval);
667                         goto done;
668                 }
669         }
670
671         netif_start_queue (net);
672         if (netif_msg_ifup (dev)) {
673                 char    *framing;
674
675                 if (dev->driver_info->flags & FLAG_FRAMING_NC)
676                         framing = "NetChip";
677                 else if (dev->driver_info->flags & FLAG_FRAMING_GL)
678                         framing = "GeneSys";
679                 else if (dev->driver_info->flags & FLAG_FRAMING_Z)
680                         framing = "Zaurus";
681                 else if (dev->driver_info->flags & FLAG_FRAMING_RN)
682                         framing = "RNDIS";
683                 else if (dev->driver_info->flags & FLAG_FRAMING_AX)
684                         framing = "ASIX";
685                 else
686                         framing = "simple";
687
688                 devinfo (dev, "open: enable queueing "
689                                 "(rx %d, tx %d) mtu %d %s framing",
690                         (int)RX_QLEN (dev), (int)TX_QLEN (dev), dev->net->mtu,
691                         framing);
692         }
693
694         // delay posting reads until we're fully open
695         tasklet_schedule (&dev->bh);
696         return retval;
697 done:
698         usb_autopm_put_interface(dev->intf);
699 done_nopm:
700         return retval;
701 }
702 EXPORT_SYMBOL_GPL(usbnet_open);
703
704 /*-------------------------------------------------------------------------*/
705
706 /* ethtool methods; minidrivers may need to add some more, but
707  * they'll probably want to use this base set.
708  */
709
710 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
711 {
712         struct usbnet *dev = netdev_priv(net);
713
714         if (!dev->mii.mdio_read)
715                 return -EOPNOTSUPP;
716
717         return mii_ethtool_gset(&dev->mii, cmd);
718 }
719 EXPORT_SYMBOL_GPL(usbnet_get_settings);
720
721 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
722 {
723         struct usbnet *dev = netdev_priv(net);
724         int retval;
725
726         if (!dev->mii.mdio_write)
727                 return -EOPNOTSUPP;
728
729         retval = mii_ethtool_sset(&dev->mii, cmd);
730
731         /* link speed/duplex might have changed */
732         if (dev->driver_info->link_reset)
733                 dev->driver_info->link_reset(dev);
734
735         return retval;
736
737 }
738 EXPORT_SYMBOL_GPL(usbnet_set_settings);
739
740 u32 usbnet_get_link (struct net_device *net)
741 {
742         struct usbnet *dev = netdev_priv(net);
743
744         /* If a check_connect is defined, return its result */
745         if (dev->driver_info->check_connect)
746                 return dev->driver_info->check_connect (dev) == 0;
747
748         /* if the device has mii operations, use those */
749         if (dev->mii.mdio_read)
750                 return mii_link_ok(&dev->mii);
751
752         /* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
753         return ethtool_op_get_link(net);
754 }
755 EXPORT_SYMBOL_GPL(usbnet_get_link);
756
757 int usbnet_nway_reset(struct net_device *net)
758 {
759         struct usbnet *dev = netdev_priv(net);
760
761         if (!dev->mii.mdio_write)
762                 return -EOPNOTSUPP;
763
764         return mii_nway_restart(&dev->mii);
765 }
766 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
767
768 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
769 {
770         struct usbnet *dev = netdev_priv(net);
771
772         strncpy (info->driver, dev->driver_name, sizeof info->driver);
773         strncpy (info->version, DRIVER_VERSION, sizeof info->version);
774         strncpy (info->fw_version, dev->driver_info->description,
775                 sizeof info->fw_version);
776         usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
777 }
778 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
779
780 u32 usbnet_get_msglevel (struct net_device *net)
781 {
782         struct usbnet *dev = netdev_priv(net);
783
784         return dev->msg_enable;
785 }
786 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
787
788 void usbnet_set_msglevel (struct net_device *net, u32 level)
789 {
790         struct usbnet *dev = netdev_priv(net);
791
792         dev->msg_enable = level;
793 }
794 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
795
796 /* drivers may override default ethtool_ops in their bind() routine */
797 static struct ethtool_ops usbnet_ethtool_ops = {
798         .get_settings           = usbnet_get_settings,
799         .set_settings           = usbnet_set_settings,
800         .get_link               = usbnet_get_link,
801         .nway_reset             = usbnet_nway_reset,
802         .get_drvinfo            = usbnet_get_drvinfo,
803         .get_msglevel           = usbnet_get_msglevel,
804         .set_msglevel           = usbnet_set_msglevel,
805 };
806
807 /*-------------------------------------------------------------------------*/
808
809 /* work that cannot be done in interrupt context uses keventd.
810  *
811  * NOTE:  with 2.5 we could do more of this using completion callbacks,
812  * especially now that control transfers can be queued.
813  */
814 static void
815 kevent (struct work_struct *work)
816 {
817         struct usbnet           *dev =
818                 container_of(work, struct usbnet, kevent);
819         int                     status;
820
821         /* usb_clear_halt() needs a thread context */
822         if (test_bit (EVENT_TX_HALT, &dev->flags)) {
823                 unlink_urbs (dev, &dev->txq);
824                 status = usb_clear_halt (dev->udev, dev->out);
825                 if (status < 0
826                                 && status != -EPIPE
827                                 && status != -ESHUTDOWN) {
828                         if (netif_msg_tx_err (dev))
829                                 deverr (dev, "can't clear tx halt, status %d",
830                                         status);
831                 } else {
832                         clear_bit (EVENT_TX_HALT, &dev->flags);
833                         if (status != -ESHUTDOWN)
834                                 netif_wake_queue (dev->net);
835                 }
836         }
837         if (test_bit (EVENT_RX_HALT, &dev->flags)) {
838                 unlink_urbs (dev, &dev->rxq);
839                 status = usb_clear_halt (dev->udev, dev->in);
840                 if (status < 0
841                                 && status != -EPIPE
842                                 && status != -ESHUTDOWN) {
843                         if (netif_msg_rx_err (dev))
844                                 deverr (dev, "can't clear rx halt, status %d",
845                                         status);
846                 } else {
847                         clear_bit (EVENT_RX_HALT, &dev->flags);
848                         tasklet_schedule (&dev->bh);
849                 }
850         }
851
852         /* tasklet could resubmit itself forever if memory is tight */
853         if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
854                 struct urb      *urb = NULL;
855
856                 if (netif_running (dev->net))
857                         urb = usb_alloc_urb (0, GFP_KERNEL);
858                 else
859                         clear_bit (EVENT_RX_MEMORY, &dev->flags);
860                 if (urb != NULL) {
861                         clear_bit (EVENT_RX_MEMORY, &dev->flags);
862                         rx_submit (dev, urb, GFP_KERNEL);
863                         tasklet_schedule (&dev->bh);
864                 }
865         }
866
867         if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
868                 struct driver_info      *info = dev->driver_info;
869                 int                     retval = 0;
870
871                 clear_bit (EVENT_LINK_RESET, &dev->flags);
872                 if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
873                         devinfo(dev, "link reset failed (%d) usbnet usb-%s-%s, %s",
874                                 retval,
875                                 dev->udev->bus->bus_name, dev->udev->devpath,
876                                 info->description);
877                 }
878         }
879
880         if (dev->flags)
881                 devdbg (dev, "kevent done, flags = 0x%lx",
882                         dev->flags);
883 }
884
885 /*-------------------------------------------------------------------------*/
886
887 static void tx_complete (struct urb *urb)
888 {
889         struct sk_buff          *skb = (struct sk_buff *) urb->context;
890         struct skb_data         *entry = (struct skb_data *) skb->cb;
891         struct usbnet           *dev = entry->dev;
892
893         if (urb->status == 0) {
894                 dev->stats.tx_packets++;
895                 dev->stats.tx_bytes += entry->length;
896         } else {
897                 dev->stats.tx_errors++;
898
899                 switch (urb->status) {
900                 case -EPIPE:
901                         usbnet_defer_kevent (dev, EVENT_TX_HALT);
902                         break;
903
904                 /* software-driven interface shutdown */
905                 case -ECONNRESET:               // async unlink
906                 case -ESHUTDOWN:                // hardware gone
907                         break;
908
909                 // like rx, tx gets controller i/o faults during khubd delays
910                 // and so it uses the same throttling mechanism.
911                 case -EPROTO:
912                 case -ETIME:
913                 case -EILSEQ:
914                         if (!timer_pending (&dev->delay)) {
915                                 mod_timer (&dev->delay,
916                                         jiffies + THROTTLE_JIFFIES);
917                                 if (netif_msg_link (dev))
918                                         devdbg (dev, "tx throttle %d",
919                                                         urb->status);
920                         }
921                         netif_stop_queue (dev->net);
922                         break;
923                 default:
924                         if (netif_msg_tx_err (dev))
925                                 devdbg (dev, "tx err %d", entry->urb->status);
926                         break;
927                 }
928         }
929
930         urb->dev = NULL;
931         entry->state = tx_done;
932         defer_bh(dev, skb, &dev->txq);
933 }
934
935 /*-------------------------------------------------------------------------*/
936
937 void usbnet_tx_timeout (struct net_device *net)
938 {
939         struct usbnet           *dev = netdev_priv(net);
940
941         unlink_urbs (dev, &dev->txq);
942         tasklet_schedule (&dev->bh);
943
944         // FIXME: device recovery -- reset?
945 }
946 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
947
948 /*-------------------------------------------------------------------------*/
949
950 int usbnet_start_xmit (struct sk_buff *skb, struct net_device *net)
951 {
952         struct usbnet           *dev = netdev_priv(net);
953         int                     length;
954         int                     retval = NET_XMIT_SUCCESS;
955         struct urb              *urb = NULL;
956         struct skb_data         *entry;
957         struct driver_info      *info = dev->driver_info;
958         unsigned long           flags;
959
960         // some devices want funky USB-level framing, for
961         // win32 driver (usually) and/or hardware quirks
962         if (info->tx_fixup) {
963                 skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
964                 if (!skb) {
965                         if (netif_msg_tx_err (dev))
966                                 devdbg (dev, "can't tx_fixup skb");
967                         goto drop;
968                 }
969         }
970         length = skb->len;
971
972         if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
973                 if (netif_msg_tx_err (dev))
974                         devdbg (dev, "no urb");
975                 goto drop;
976         }
977
978         entry = (struct skb_data *) skb->cb;
979         entry->urb = urb;
980         entry->dev = dev;
981         entry->state = tx_start;
982         entry->length = length;
983
984         usb_fill_bulk_urb (urb, dev->udev, dev->out,
985                         skb->data, skb->len, tx_complete, skb);
986
987         /* don't assume the hardware handles USB_ZERO_PACKET
988          * NOTE:  strictly conforming cdc-ether devices should expect
989          * the ZLP here, but ignore the one-byte packet.
990          */
991         if ((length % dev->maxpacket) == 0) {
992                 urb->transfer_buffer_length++;
993                 if (skb_tailroom(skb)) {
994                         skb->data[skb->len] = 0;
995                         __skb_put(skb, 1);
996                 }
997         }
998
999         spin_lock_irqsave (&dev->txq.lock, flags);
1000
1001         switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1002         case -EPIPE:
1003                 netif_stop_queue (net);
1004                 usbnet_defer_kevent (dev, EVENT_TX_HALT);
1005                 break;
1006         default:
1007                 if (netif_msg_tx_err (dev))
1008                         devdbg (dev, "tx: submit urb err %d", retval);
1009                 break;
1010         case 0:
1011                 net->trans_start = jiffies;
1012                 __skb_queue_tail (&dev->txq, skb);
1013                 if (dev->txq.qlen >= TX_QLEN (dev))
1014                         netif_stop_queue (net);
1015         }
1016         spin_unlock_irqrestore (&dev->txq.lock, flags);
1017
1018         if (retval) {
1019                 if (netif_msg_tx_err (dev))
1020                         devdbg (dev, "drop, code %d", retval);
1021 drop:
1022                 retval = NET_XMIT_SUCCESS;
1023                 dev->stats.tx_dropped++;
1024                 if (skb)
1025                         dev_kfree_skb_any (skb);
1026                 usb_free_urb (urb);
1027         } else if (netif_msg_tx_queued (dev)) {
1028                 devdbg (dev, "> tx, len %d, type 0x%x",
1029                         length, skb->protocol);
1030         }
1031         return retval;
1032 }
1033 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1034
1035 /*-------------------------------------------------------------------------*/
1036
1037 // tasklet (work deferred from completions, in_irq) or timer
1038
1039 static void usbnet_bh (unsigned long param)
1040 {
1041         struct usbnet           *dev = (struct usbnet *) param;
1042         struct sk_buff          *skb;
1043         struct skb_data         *entry;
1044
1045         while ((skb = skb_dequeue (&dev->done))) {
1046                 entry = (struct skb_data *) skb->cb;
1047                 switch (entry->state) {
1048                 case rx_done:
1049                         entry->state = rx_cleanup;
1050                         rx_process (dev, skb);
1051                         continue;
1052                 case tx_done:
1053                 case rx_cleanup:
1054                         usb_free_urb (entry->urb);
1055                         dev_kfree_skb (skb);
1056                         continue;
1057                 default:
1058                         devdbg (dev, "bogus skb state %d", entry->state);
1059                 }
1060         }
1061
1062         // waiting for all pending urbs to complete?
1063         if (dev->wait) {
1064                 if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
1065                         wake_up (dev->wait);
1066                 }
1067
1068         // or are we maybe short a few urbs?
1069         } else if (netif_running (dev->net)
1070                         && netif_device_present (dev->net)
1071                         && !timer_pending (&dev->delay)
1072                         && !test_bit (EVENT_RX_HALT, &dev->flags)) {
1073                 int     temp = dev->rxq.qlen;
1074                 int     qlen = RX_QLEN (dev);
1075
1076                 if (temp < qlen) {
1077                         struct urb      *urb;
1078                         int             i;
1079
1080                         // don't refill the queue all at once
1081                         for (i = 0; i < 10 && dev->rxq.qlen < qlen; i++) {
1082                                 urb = usb_alloc_urb (0, GFP_ATOMIC);
1083                                 if (urb != NULL)
1084                                         rx_submit (dev, urb, GFP_ATOMIC);
1085                         }
1086                         if (temp != dev->rxq.qlen && netif_msg_link (dev))
1087                                 devdbg (dev, "rxqlen %d --> %d",
1088                                                 temp, dev->rxq.qlen);
1089                         if (dev->rxq.qlen < qlen)
1090                                 tasklet_schedule (&dev->bh);
1091                 }
1092                 if (dev->txq.qlen < TX_QLEN (dev))
1093                         netif_wake_queue (dev->net);
1094         }
1095 }
1096
1097
1098 \f
1099 /*-------------------------------------------------------------------------
1100  *
1101  * USB Device Driver support
1102  *
1103  *-------------------------------------------------------------------------*/
1104
1105 // precondition: never called in_interrupt
1106
1107 void usbnet_disconnect (struct usb_interface *intf)
1108 {
1109         struct usbnet           *dev;
1110         struct usb_device       *xdev;
1111         struct net_device       *net;
1112
1113         dev = usb_get_intfdata(intf);
1114         usb_set_intfdata(intf, NULL);
1115         if (!dev)
1116                 return;
1117
1118         xdev = interface_to_usbdev (intf);
1119
1120         if (netif_msg_probe (dev))
1121                 devinfo (dev, "unregister '%s' usb-%s-%s, %s",
1122                         intf->dev.driver->name,
1123                         xdev->bus->bus_name, xdev->devpath,
1124                         dev->driver_info->description);
1125
1126         net = dev->net;
1127         unregister_netdev (net);
1128
1129         /* we don't hold rtnl here ... */
1130         flush_scheduled_work ();
1131
1132         if (dev->driver_info->unbind)
1133                 dev->driver_info->unbind (dev, intf);
1134
1135         free_netdev(net);
1136         usb_put_dev (xdev);
1137 }
1138 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1139
1140 static const struct net_device_ops usbnet_netdev_ops = {
1141         .ndo_open               = usbnet_open,
1142         .ndo_stop               = usbnet_stop,
1143         .ndo_start_xmit         = usbnet_start_xmit,
1144         .ndo_tx_timeout         = usbnet_tx_timeout,
1145         .ndo_change_mtu         = usbnet_change_mtu,
1146         .ndo_set_mac_address    = eth_mac_addr,
1147         .ndo_validate_addr      = eth_validate_addr,
1148 };
1149
1150 /*-------------------------------------------------------------------------*/
1151
1152 // precondition: never called in_interrupt
1153
1154 int
1155 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1156 {
1157         struct usbnet                   *dev;
1158         struct net_device               *net;
1159         struct usb_host_interface       *interface;
1160         struct driver_info              *info;
1161         struct usb_device               *xdev;
1162         int                             status;
1163         const char                      *name;
1164
1165         name = udev->dev.driver->name;
1166         info = (struct driver_info *) prod->driver_info;
1167         if (!info) {
1168                 dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1169                 return -ENODEV;
1170         }
1171         xdev = interface_to_usbdev (udev);
1172         interface = udev->cur_altsetting;
1173
1174         usb_get_dev (xdev);
1175
1176         status = -ENOMEM;
1177
1178         // set up our own records
1179         net = alloc_etherdev(sizeof(*dev));
1180         if (!net) {
1181                 dbg ("can't kmalloc dev");
1182                 goto out;
1183         }
1184
1185         dev = netdev_priv(net);
1186         dev->udev = xdev;
1187         dev->intf = udev;
1188         dev->driver_info = info;
1189         dev->driver_name = name;
1190         dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1191                                 | NETIF_MSG_PROBE | NETIF_MSG_LINK);
1192         skb_queue_head_init (&dev->rxq);
1193         skb_queue_head_init (&dev->txq);
1194         skb_queue_head_init (&dev->done);
1195         dev->bh.func = usbnet_bh;
1196         dev->bh.data = (unsigned long) dev;
1197         INIT_WORK (&dev->kevent, kevent);
1198         dev->delay.function = usbnet_bh;
1199         dev->delay.data = (unsigned long) dev;
1200         init_timer (&dev->delay);
1201         mutex_init (&dev->phy_mutex);
1202
1203         dev->net = net;
1204         strcpy (net->name, "usb%d");
1205         memcpy (net->dev_addr, node_id, sizeof node_id);
1206
1207         /* rx and tx sides can use different message sizes;
1208          * bind() should set rx_urb_size in that case.
1209          */
1210         dev->hard_mtu = net->mtu + net->hard_header_len;
1211 #if 0
1212 // dma_supported() is deeply broken on almost all architectures
1213         // possible with some EHCI controllers
1214         if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1215                 net->features |= NETIF_F_HIGHDMA;
1216 #endif
1217
1218         net->netdev_ops = &usbnet_netdev_ops;
1219         net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1220         net->ethtool_ops = &usbnet_ethtool_ops;
1221
1222         // allow device-specific bind/init procedures
1223         // NOTE net->name still not usable ...
1224         if (info->bind) {
1225                 status = info->bind (dev, udev);
1226                 if (status < 0)
1227                         goto out1;
1228
1229                 // heuristic:  "usb%d" for links we know are two-host,
1230                 // else "eth%d" when there's reasonable doubt.  userspace
1231                 // can rename the link if it knows better.
1232                 if ((dev->driver_info->flags & FLAG_ETHER) != 0
1233                                 && (net->dev_addr [0] & 0x02) == 0)
1234                         strcpy (net->name, "eth%d");
1235                 /* WLAN devices should always be named "wlan%d" */
1236                 if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1237                         strcpy(net->name, "wlan%d");
1238
1239                 /* maybe the remote can't receive an Ethernet MTU */
1240                 if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1241                         net->mtu = dev->hard_mtu - net->hard_header_len;
1242         } else if (!info->in || !info->out)
1243                 status = usbnet_get_endpoints (dev, udev);
1244         else {
1245                 dev->in = usb_rcvbulkpipe (xdev, info->in);
1246                 dev->out = usb_sndbulkpipe (xdev, info->out);
1247                 if (!(info->flags & FLAG_NO_SETINT))
1248                         status = usb_set_interface (xdev,
1249                                 interface->desc.bInterfaceNumber,
1250                                 interface->desc.bAlternateSetting);
1251                 else
1252                         status = 0;
1253
1254         }
1255         if (status >= 0 && dev->status)
1256                 status = init_status (dev, udev);
1257         if (status < 0)
1258                 goto out3;
1259
1260         if (!dev->rx_urb_size)
1261                 dev->rx_urb_size = dev->hard_mtu;
1262         dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1263
1264         SET_NETDEV_DEV(net, &udev->dev);
1265         status = register_netdev (net);
1266         if (status)
1267                 goto out3;
1268         if (netif_msg_probe (dev))
1269                 devinfo (dev, "register '%s' at usb-%s-%s, %s, %pM",
1270                         udev->dev.driver->name,
1271                         xdev->bus->bus_name, xdev->devpath,
1272                         dev->driver_info->description,
1273                         net->dev_addr);
1274
1275         // ok, it's ready to go.
1276         usb_set_intfdata (udev, dev);
1277
1278         // start as if the link is up
1279         netif_device_attach (net);
1280
1281         return 0;
1282
1283 out3:
1284         if (info->unbind)
1285                 info->unbind (dev, udev);
1286 out1:
1287         free_netdev(net);
1288 out:
1289         usb_put_dev(xdev);
1290         return status;
1291 }
1292 EXPORT_SYMBOL_GPL(usbnet_probe);
1293
1294 /*-------------------------------------------------------------------------*/
1295
1296 /*
1297  * suspend the whole driver as soon as the first interface is suspended
1298  * resume only when the last interface is resumed
1299  */
1300
1301 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1302 {
1303         struct usbnet           *dev = usb_get_intfdata(intf);
1304
1305         if (!dev->suspend_count++) {
1306                 /*
1307                  * accelerate emptying of the rx and queues, to avoid
1308                  * having everything error out.
1309                  */
1310                 netif_device_detach (dev->net);
1311                 (void) unlink_urbs (dev, &dev->rxq);
1312                 (void) unlink_urbs (dev, &dev->txq);
1313                 /*
1314                  * reattach so runtime management can use and
1315                  * wake the device
1316                  */
1317                 netif_device_attach (dev->net);
1318         }
1319         return 0;
1320 }
1321 EXPORT_SYMBOL_GPL(usbnet_suspend);
1322
1323 int usbnet_resume (struct usb_interface *intf)
1324 {
1325         struct usbnet           *dev = usb_get_intfdata(intf);
1326
1327         if (!--dev->suspend_count)
1328                 tasklet_schedule (&dev->bh);
1329
1330         return 0;
1331 }
1332 EXPORT_SYMBOL_GPL(usbnet_resume);
1333
1334
1335 /*-------------------------------------------------------------------------*/
1336
1337 static int __init usbnet_init(void)
1338 {
1339         /* compiler should optimize this out */
1340         BUILD_BUG_ON (sizeof (((struct sk_buff *)0)->cb)
1341                         < sizeof (struct skb_data));
1342
1343         random_ether_addr(node_id);
1344         return 0;
1345 }
1346 module_init(usbnet_init);
1347
1348 static void __exit usbnet_exit(void)
1349 {
1350 }
1351 module_exit(usbnet_exit);
1352
1353 MODULE_AUTHOR("David Brownell");
1354 MODULE_DESCRIPTION("USB network driver framework");
1355 MODULE_LICENSE("GPL");