Pileus Git - ~andy/linux/blob - 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 #include <linux/slab.h>
  47 #include <linux/kernel.h>
  48 #include <linux/pm_runtime.h>
  49
  50 #define DRIVER_VERSION          "22-Aug-2005"
  51
  52
  53 /*-------------------------------------------------------------------------*/
  54
  55 /*
  56  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
  57  * Several dozen bytes of IPv4 data can fit in two such transactions.
  58  * One maximum size Ethernet packet takes twenty four of them.
  59  * For high speed, each frame comfortably fits almost 36 max size
  60  * Ethernet packets (so queues should be bigger).
  61  *
  62  * REVISIT qlens should be members of 'struct usbnet'; the goal is to
  63  * let the USB host controller be busy for 5msec or more before an irq
  64  * is required, under load.  Jumbograms change the equation.
  65  */
  66 #define RX_MAX_QUEUE_MEMORY (60 * 1518)
  67 #define RX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
  68                         (RX_MAX_QUEUE_MEMORY/(dev)->rx_urb_size) : 4)
  69 #define TX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
  70                         (RX_MAX_QUEUE_MEMORY/(dev)->hard_mtu) : 4)
  71
  72 // reawaken network queue this soon after stopping; else watchdog barks
  73 #define TX_TIMEOUT_JIFFIES      (5*HZ)
  74
  75 // throttle rx/tx briefly after some faults, so khubd might disconnect()
  76 // us (it polls at HZ/4 usually) before we report too many false errors.
  77 #define THROTTLE_JIFFIES        (HZ/8)
  78
  79 // between wakeups
  80 #define UNLINK_TIMEOUT_MS       3
  81
  82 /*-------------------------------------------------------------------------*/
  83
  84 // randomly generated ethernet address
  85 static u8       node_id [ETH_ALEN];
  86
  87 static const char driver_name [] = "usbnet";
  88
  89 /* use ethtool to change the level for any given device */
  90 static int msg_level = -1;
  91 module_param (msg_level, int, 0);
  92 MODULE_PARM_DESC (msg_level, "Override default message level");
  93
  94 /*-------------------------------------------------------------------------*/
  95
  96 /* handles CDC Ethernet and many other network "bulk data" interfaces */
  97 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
  98 {
  99         int                             tmp;
 100         struct usb_host_interface       *alt = NULL;
 101         struct usb_host_endpoint        *in = NULL, *out = NULL;
 102         struct usb_host_endpoint        *status = NULL;
 103
 104         for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
 105                 unsigned        ep;
 106
 107                 in = out = status = NULL;
 108                 alt = intf->altsetting + tmp;
 109
 110                 /* take the first altsetting with in-bulk + out-bulk;
 111                  * remember any status endpoint, just in case;
 112                  * ignore other endpoints and altsettings.
 113                  */
 114                 for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
 115                         struct usb_host_endpoint        *e;
 116                         int                             intr = 0;
 117
 118                         e = alt->endpoint + ep;
 119                         switch (e->desc.bmAttributes) {
 120                         case USB_ENDPOINT_XFER_INT:
 121                                 if (!usb_endpoint_dir_in(&e->desc))
 122                                         continue;
 123                                 intr = 1;
 124                                 /* FALLTHROUGH */
 125                         case USB_ENDPOINT_XFER_BULK:
 126                                 break;
 127                         default:
 128                                 continue;
 129                         }
 130                         if (usb_endpoint_dir_in(&e->desc)) {
 131                                 if (!intr && !in)
 132                                         in = e;
 133                                 else if (intr && !status)
 134                                         status = e;
 135                         } else {
 136                                 if (!out)
 137                                         out = e;
 138                         }
 139                 }
 140                 if (in && out)
 141                         break;
 142         }
 143         if (!alt || !in || !out)
 144                 return -EINVAL;
 145
 146         if (alt->desc.bAlternateSetting != 0 ||
 147             !(dev->driver_info->flags & FLAG_NO_SETINT)) {
 148                 tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
 149                                 alt->desc.bAlternateSetting);
 150                 if (tmp < 0)
 151                         return tmp;
 152         }
 153
 154         dev->in = usb_rcvbulkpipe (dev->udev,
 155                         in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
 156         dev->out = usb_sndbulkpipe (dev->udev,
 157                         out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
 158         dev->status = status;
 159         return 0;
 160 }
 161 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
 162
 163 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
 164 {
 165         int             tmp, i;
 166         unsigned char   buf [13];
 167
 168         tmp = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
 169         if (tmp != 12) {
 170                 dev_dbg(&dev->udev->dev,
 171                         "bad MAC string %d fetch, %d\n", iMACAddress, tmp);
 172                 if (tmp >= 0)
 173                         tmp = -EINVAL;
 174                 return tmp;
 175         }
 176         for (i = tmp = 0; i < 6; i++, tmp += 2)
 177                 dev->net->dev_addr [i] =
 178                         (hex_to_bin(buf[tmp]) << 4) + hex_to_bin(buf[tmp + 1]);
 179         return 0;
 180 }
 181 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
 182
 183 static void intr_complete (struct urb *urb)
 184 {
 185         struct usbnet   *dev = urb->context;
 186         int             status = urb->status;
 187
 188         switch (status) {
 189         /* success */
 190         case 0:
 191                 dev->driver_info->status(dev, urb);
 192                 break;
 193
 194         /* software-driven interface shutdown */
 195         case -ENOENT:           /* urb killed */
 196         case -ESHUTDOWN:        /* hardware gone */
 197                 netif_dbg(dev, ifdown, dev->net,
 198                           "intr shutdown, code %d\n", status);
 199                 return;
 200
 201         /* NOTE:  not throttling like RX/TX, since this endpoint
 202          * already polls infrequently
 203          */
 204         default:
 205                 netdev_dbg(dev->net, "intr status %d\n", status);
 206                 break;
 207         }
 208
 209         if (!netif_running (dev->net))
 210                 return;
 211
 212         status = usb_submit_urb (urb, GFP_ATOMIC);
 213         if (status != 0)
 214                 netif_err(dev, timer, dev->net,
 215                           "intr resubmit --> %d\n", status);
 216 }
 217
 218 static int init_status (struct usbnet *dev, struct usb_interface *intf)
 219 {
 220         char            *buf = NULL;
 221         unsigned        pipe = 0;
 222         unsigned        maxp;
 223         unsigned        period;
 224
 225         if (!dev->driver_info->status)
 226                 return 0;
 227
 228         pipe = usb_rcvintpipe (dev->udev,
 229                         dev->status->desc.bEndpointAddress
 230                                 & USB_ENDPOINT_NUMBER_MASK);
 231         maxp = usb_maxpacket (dev->udev, pipe, 0);
 232
 233         /* avoid 1 msec chatter:  min 8 msec poll rate */
 234         period = max ((int) dev->status->desc.bInterval,
 235                 (dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
 236
 237         buf = kmalloc (maxp, GFP_KERNEL);
 238         if (buf) {
 239                 dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
 240                 if (!dev->interrupt) {
 241                         kfree (buf);
 242                         return -ENOMEM;
 243                 } else {
 244                         usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
 245                                 buf, maxp, intr_complete, dev, period);
 246                         dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
 247                         dev_dbg(&intf->dev,
 248                                 "status ep%din, %d bytes period %d\n",
 249                                 usb_pipeendpoint(pipe), maxp, period);
 250                 }
 251         }
 252         return 0;
 253 }
 254
 255 /* Passes this packet up the stack, updating its accounting.
 256  * Some link protocols batch packets, so their rx_fixup paths
 257  * can return clones as well as just modify the original skb.
 258  */
 259 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
 260 {
 261         int     status;
 262
 263         if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
 264                 skb_queue_tail(&dev->rxq_pause, skb);
 265                 return;
 266         }
 267
 268         skb->protocol = eth_type_trans (skb, dev->net);
 269         dev->net->stats.rx_packets++;
 270         dev->net->stats.rx_bytes += skb->len;
 271
 272         netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
 273                   skb->len + sizeof (struct ethhdr), skb->protocol);
 274         memset (skb->cb, 0, sizeof (struct skb_data));
 275
 276         if (skb_defer_rx_timestamp(skb))
 277                 return;
 278
 279         status = netif_rx (skb);
 280         if (status != NET_RX_SUCCESS)
 281                 netif_dbg(dev, rx_err, dev->net,
 282                           "netif_rx status %d\n", status);
 283 }
 284 EXPORT_SYMBOL_GPL(usbnet_skb_return);
 285
 286 \f
 287 /*-------------------------------------------------------------------------
 288  *
 289  * Network Device Driver (peer link to "Host Device", from USB host)
 290  *
 291  *-------------------------------------------------------------------------*/
 292
 293 int usbnet_change_mtu (struct net_device *net, int new_mtu)
 294 {
 295         struct usbnet   *dev = netdev_priv(net);
 296         int             ll_mtu = new_mtu + net->hard_header_len;
 297         int             old_hard_mtu = dev->hard_mtu;
 298         int             old_rx_urb_size = dev->rx_urb_size;
 299
 300         if (new_mtu <= 0)
 301                 return -EINVAL;
 302         // no second zero-length packet read wanted after mtu-sized packets
 303         if ((ll_mtu % dev->maxpacket) == 0)
 304                 return -EDOM;
 305         net->mtu = new_mtu;
 306
 307         dev->hard_mtu = net->mtu + net->hard_header_len;
 308         if (dev->rx_urb_size == old_hard_mtu) {
 309                 dev->rx_urb_size = dev->hard_mtu;
 310                 if (dev->rx_urb_size > old_rx_urb_size)
 311                         usbnet_unlink_rx_urbs(dev);
 312         }
 313
 314         return 0;
 315 }
 316 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
 317
 318 /* The caller must hold list->lock */
 319 static void __usbnet_queue_skb(struct sk_buff_head *list,
 320                         struct sk_buff *newsk, enum skb_state state)
 321 {
 322         struct skb_data *entry = (struct skb_data *) newsk->cb;
 323
 324         __skb_queue_tail(list, newsk);
 325         entry->state = state;
 326 }
 327
 328 /*-------------------------------------------------------------------------*/
 329
 330 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
 331  * completion callbacks.  2.5 should have fixed those bugs...
 332  */
 333
 334 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
 335                 struct sk_buff_head *list, enum skb_state state)
 336 {
 337         unsigned long           flags;
 338         enum skb_state          old_state;
 339         struct skb_data *entry = (struct skb_data *) skb->cb;
 340
 341         spin_lock_irqsave(&list->lock, flags);
 342         old_state = entry->state;
 343         entry->state = state;
 344         __skb_unlink(skb, list);
 345         spin_unlock(&list->lock);
 346         spin_lock(&dev->done.lock);
 347         __skb_queue_tail(&dev->done, skb);
 348         if (dev->done.qlen == 1)
 349                 tasklet_schedule(&dev->bh);
 350         spin_unlock_irqrestore(&dev->done.lock, flags);
 351         return old_state;
 352 }
 353
 354 /* some work can't be done in tasklets, so we use keventd
 355  *
 356  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
 357  * but tasklet_schedule() doesn't.  hope the failure is rare.
 358  */
 359 void usbnet_defer_kevent (struct usbnet *dev, int work)
 360 {
 361         set_bit (work, &dev->flags);
 362         if (!schedule_work (&dev->kevent)) {
 363                 if (net_ratelimit())
 364                         netdev_err(dev->net, "kevent %d may have been dropped\n", work);
 365         } else {
 366                 netdev_dbg(dev->net, "kevent %d scheduled\n", work);
 367         }
 368 }
 369 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
 370
 371 /*-------------------------------------------------------------------------*/
 372
 373 static void rx_complete (struct urb *urb);
 374
 375 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
 376 {
 377         struct sk_buff          *skb;
 378         struct skb_data         *entry;
 379         int                     retval = 0;
 380         unsigned long           lockflags;
 381         size_t                  size = dev->rx_urb_size;
 382
 383         skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
 384         if (!skb) {
 385                 netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
 386                 usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
 387                 usb_free_urb (urb);
 388                 return -ENOMEM;
 389         }
 390
 391         entry = (struct skb_data *) skb->cb;
 392         entry->urb = urb;
 393         entry->dev = dev;
 394         entry->length = 0;
 395
 396         usb_fill_bulk_urb (urb, dev->udev, dev->in,
 397                 skb->data, size, rx_complete, skb);
 398
 399         spin_lock_irqsave (&dev->rxq.lock, lockflags);
 400
 401         if (netif_running (dev->net) &&
 402             netif_device_present (dev->net) &&
 403             !test_bit (EVENT_RX_HALT, &dev->flags) &&
 404             !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
 405                 switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
 406                 case -EPIPE:
 407                         usbnet_defer_kevent (dev, EVENT_RX_HALT);
 408                         break;
 409                 case -ENOMEM:
 410                         usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
 411                         break;
 412                 case -ENODEV:
 413                         netif_dbg(dev, ifdown, dev->net, "device gone\n");
 414                         netif_device_detach (dev->net);
 415                         break;
 416                 case -EHOSTUNREACH:
 417                         retval = -ENOLINK;
 418                         break;
 419                 default:
 420                         netif_dbg(dev, rx_err, dev->net,
 421                                   "rx submit, %d\n", retval);
 422                         tasklet_schedule (&dev->bh);
 423                         break;
 424                 case 0:
 425                         __usbnet_queue_skb(&dev->rxq, skb, rx_start);
 426                 }
 427         } else {
 428                 netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
 429                 retval = -ENOLINK;
 430         }
 431         spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
 432         if (retval) {
 433                 dev_kfree_skb_any (skb);
 434                 usb_free_urb (urb);
 435         }
 436         return retval;
 437 }
 438
 439
 440 /*-------------------------------------------------------------------------*/
 441
 442 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
 443 {
 444         if (dev->driver_info->rx_fixup &&
 445             !dev->driver_info->rx_fixup (dev, skb)) {
 446                 /* With RX_ASSEMBLE, rx_fixup() must update counters */
 447                 if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
 448                         dev->net->stats.rx_errors++;
 449                 goto done;
 450         }
 451         // else network stack removes extra byte if we forced a short packet
 452
 453         if (skb->len) {
 454                 /* all data was already cloned from skb inside the driver */
 455                 if (dev->driver_info->flags & FLAG_MULTI_PACKET)
 456                         dev_kfree_skb_any(skb);
 457                 else
 458                         usbnet_skb_return(dev, skb);
 459                 return;
 460         }
 461
 462         netif_dbg(dev, rx_err, dev->net, "drop\n");
 463         dev->net->stats.rx_errors++;
 464 done:
 465         skb_queue_tail(&dev->done, skb);
 466 }
 467
 468 /*-------------------------------------------------------------------------*/
 469
 470 static void rx_complete (struct urb *urb)
 471 {
 472         struct sk_buff          *skb = (struct sk_buff *) urb->context;
 473         struct skb_data         *entry = (struct skb_data *) skb->cb;
 474         struct usbnet           *dev = entry->dev;
 475         int                     urb_status = urb->status;
 476         enum skb_state          state;
 477
 478         skb_put (skb, urb->actual_length);
 479         state = rx_done;
 480         entry->urb = NULL;
 481
 482         switch (urb_status) {
 483         /* success */
 484         case 0:
 485                 if (skb->len < dev->net->hard_header_len) {
 486                         state = rx_cleanup;
 487                         dev->net->stats.rx_errors++;
 488                         dev->net->stats.rx_length_errors++;
 489                         netif_dbg(dev, rx_err, dev->net,
 490                                   "rx length %d\n", skb->len);
 491                 }
 492                 break;
 493
 494         /* stalls need manual reset. this is rare ... except that
 495          * when going through USB 2.0 TTs, unplug appears this way.
 496          * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
 497          * storm, recovering as needed.
 498          */
 499         case -EPIPE:
 500                 dev->net->stats.rx_errors++;
 501                 usbnet_defer_kevent (dev, EVENT_RX_HALT);
 502                 // FALLTHROUGH
 503
 504         /* software-driven interface shutdown */
 505         case -ECONNRESET:               /* async unlink */
 506         case -ESHUTDOWN:                /* hardware gone */
 507                 netif_dbg(dev, ifdown, dev->net,
 508                           "rx shutdown, code %d\n", urb_status);
 509                 goto block;
 510
 511         /* we get controller i/o faults during khubd disconnect() delays.
 512          * throttle down resubmits, to avoid log floods; just temporarily,
 513          * so we still recover when the fault isn't a khubd delay.
 514          */
 515         case -EPROTO:
 516         case -ETIME:
 517         case -EILSEQ:
 518                 dev->net->stats.rx_errors++;
 519                 if (!timer_pending (&dev->delay)) {
 520                         mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
 521                         netif_dbg(dev, link, dev->net,
 522                                   "rx throttle %d\n", urb_status);
 523                 }
 524 block:
 525                 state = rx_cleanup;
 526                 entry->urb = urb;
 527                 urb = NULL;
 528                 break;
 529
 530         /* data overrun ... flush fifo? */
 531         case -EOVERFLOW:
 532                 dev->net->stats.rx_over_errors++;
 533                 // FALLTHROUGH
 534
 535         default:
 536                 state = rx_cleanup;
 537                 dev->net->stats.rx_errors++;
 538                 netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
 539                 break;
 540         }
 541
 542         state = defer_bh(dev, skb, &dev->rxq, state);
 543
 544         if (urb) {
 545                 if (netif_running (dev->net) &&
 546                     !test_bit (EVENT_RX_HALT, &dev->flags) &&
 547                     state != unlink_start) {
 548                         rx_submit (dev, urb, GFP_ATOMIC);
 549                         usb_mark_last_busy(dev->udev);
 550                         return;
 551                 }
 552                 usb_free_urb (urb);
 553         }
 554         netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
 555 }
 556
 557 /*-------------------------------------------------------------------------*/
 558 void usbnet_pause_rx(struct usbnet *dev)
 559 {
 560         set_bit(EVENT_RX_PAUSED, &dev->flags);
 561
 562         netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
 563 }
 564 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
 565
 566 void usbnet_resume_rx(struct usbnet *dev)
 567 {
 568         struct sk_buff *skb;
 569         int num = 0;
 570
 571         clear_bit(EVENT_RX_PAUSED, &dev->flags);
 572
 573         while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
 574                 usbnet_skb_return(dev, skb);
 575                 num++;
 576         }
 577
 578         tasklet_schedule(&dev->bh);
 579
 580         netif_dbg(dev, rx_status, dev->net,
 581                   "paused rx queue disabled, %d skbs requeued\n", num);
 582 }
 583 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
 584
 585 void usbnet_purge_paused_rxq(struct usbnet *dev)
 586 {
 587         skb_queue_purge(&dev->rxq_pause);
 588 }
 589 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
 590
 591 /*-------------------------------------------------------------------------*/
 592
 593 // unlink pending rx/tx; completion handlers do all other cleanup
 594
 595 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
 596 {
 597         unsigned long           flags;
 598         struct sk_buff          *skb;
 599         int                     count = 0;
 600
 601         spin_lock_irqsave (&q->lock, flags);
 602         while (!skb_queue_empty(q)) {
 603                 struct skb_data         *entry;
 604                 struct urb              *urb;
 605                 int                     retval;
 606
 607                 skb_queue_walk(q, skb) {
 608                         entry = (struct skb_data *) skb->cb;
 609                         if (entry->state != unlink_start)
 610                                 goto found;
 611                 }
 612                 break;
 613 found:
 614                 entry->state = unlink_start;
 615                 urb = entry->urb;
 616
 617                 /*
 618                  * Get reference count of the URB to avoid it to be
 619                  * freed during usb_unlink_urb, which may trigger
 620                  * use-after-free problem inside usb_unlink_urb since
 621                  * usb_unlink_urb is always racing with .complete
 622                  * handler(include defer_bh).
 623                  */
 624                 usb_get_urb(urb);
 625                 spin_unlock_irqrestore(&q->lock, flags);
 626                 // during some PM-driven resume scenarios,
 627                 // these (async) unlinks complete immediately
 628                 retval = usb_unlink_urb (urb);
 629                 if (retval != -EINPROGRESS && retval != 0)
 630                         netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
 631                 else
 632                         count++;
 633                 usb_put_urb(urb);
 634                 spin_lock_irqsave(&q->lock, flags);
 635         }
 636         spin_unlock_irqrestore (&q->lock, flags);
 637         return count;
 638 }
 639
 640 // Flush all pending rx urbs
 641 // minidrivers may need to do this when the MTU changes
 642
 643 void usbnet_unlink_rx_urbs(struct usbnet *dev)
 644 {
 645         if (netif_running(dev->net)) {
 646                 (void) unlink_urbs (dev, &dev->rxq);
 647                 tasklet_schedule(&dev->bh);
 648         }
 649 }
 650 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
 651
 652 /*-------------------------------------------------------------------------*/
 653
 654 // precondition: never called in_interrupt
 655 static void usbnet_terminate_urbs(struct usbnet *dev)
 656 {
 657         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
 658         DECLARE_WAITQUEUE(wait, current);
 659         int temp;
 660
 661         /* ensure there are no more active urbs */
 662         add_wait_queue(&unlink_wakeup, &wait);
 663         set_current_state(TASK_UNINTERRUPTIBLE);
 664         dev->wait = &unlink_wakeup;
 665         temp = unlink_urbs(dev, &dev->txq) +
 666                 unlink_urbs(dev, &dev->rxq);
 667
 668         /* maybe wait for deletions to finish. */
 669         while (!skb_queue_empty(&dev->rxq)
 670                 && !skb_queue_empty(&dev->txq)
 671                 && !skb_queue_empty(&dev->done)) {
 672                         schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
 673                         set_current_state(TASK_UNINTERRUPTIBLE);
 674                         netif_dbg(dev, ifdown, dev->net,
 675                                   "waited for %d urb completions\n", temp);
 676         }
 677         set_current_state(TASK_RUNNING);
 678         dev->wait = NULL;
 679         remove_wait_queue(&unlink_wakeup, &wait);
 680 }
 681
 682 int usbnet_stop (struct net_device *net)
 683 {
 684         struct usbnet           *dev = netdev_priv(net);
 685         struct driver_info      *info = dev->driver_info;
 686         int                     retval;
 687
 688         clear_bit(EVENT_DEV_OPEN, &dev->flags);
 689         netif_stop_queue (net);
 690
 691         netif_info(dev, ifdown, dev->net,
 692                    "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
 693                    net->stats.rx_packets, net->stats.tx_packets,
 694                    net->stats.rx_errors, net->stats.tx_errors);
 695
 696         /* allow minidriver to stop correctly (wireless devices to turn off
 697          * radio etc) */
 698         if (info->stop) {
 699                 retval = info->stop(dev);
 700                 if (retval < 0)
 701                         netif_info(dev, ifdown, dev->net,
 702                                    "stop fail (%d) usbnet usb-%s-%s, %s\n",
 703                                    retval,
 704                                    dev->udev->bus->bus_name, dev->udev->devpath,
 705                                    info->description);
 706         }
 707
 708         if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
 709                 usbnet_terminate_urbs(dev);
 710
 711         usb_kill_urb(dev->interrupt);
 712
 713         usbnet_purge_paused_rxq(dev);
 714
 715         /* deferred work (task, timer, softirq) must also stop.
 716          * can't flush_scheduled_work() until we drop rtnl (later),
 717          * else workers could deadlock; so make workers a NOP.
 718          */
 719         dev->flags = 0;
 720         del_timer_sync (&dev->delay);
 721         tasklet_kill (&dev->bh);
 722         if (info->manage_power &&
 723             !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags))
 724                 info->manage_power(dev, 0);
 725         else
 726                 usb_autopm_put_interface(dev->intf);
 727
 728         return 0;
 729 }
 730 EXPORT_SYMBOL_GPL(usbnet_stop);
 731
 732 /*-------------------------------------------------------------------------*/
 733
 734 // posts reads, and enables write queuing
 735
 736 // precondition: never called in_interrupt
 737
 738 int usbnet_open (struct net_device *net)
 739 {
 740         struct usbnet           *dev = netdev_priv(net);
 741         int                     retval;
 742         struct driver_info      *info = dev->driver_info;
 743
 744         if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
 745                 netif_info(dev, ifup, dev->net,
 746                            "resumption fail (%d) usbnet usb-%s-%s, %s\n",
 747                            retval,
 748                            dev->udev->bus->bus_name,
 749                            dev->udev->devpath,
 750                            info->description);
 751                 goto done_nopm;
 752         }
 753
 754         // put into "known safe" state
 755         if (info->reset && (retval = info->reset (dev)) < 0) {
 756                 netif_info(dev, ifup, dev->net,
 757                            "open reset fail (%d) usbnet usb-%s-%s, %s\n",
 758                            retval,
 759                            dev->udev->bus->bus_name,
 760                            dev->udev->devpath,
 761                            info->description);
 762                 goto done;
 763         }
 764
 765         // insist peer be connected
 766         if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
 767                 netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
 768                 goto done;
 769         }
 770
 771         /* start any status interrupt transfer */
 772         if (dev->interrupt) {
 773                 retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
 774                 if (retval < 0) {
 775                         netif_err(dev, ifup, dev->net,
 776                                   "intr submit %d\n", retval);
 777                         goto done;
 778                 }
 779         }
 780
 781         set_bit(EVENT_DEV_OPEN, &dev->flags);
 782         netif_start_queue (net);
 783         netif_info(dev, ifup, dev->net,
 784                    "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
 785                    (int)RX_QLEN(dev), (int)TX_QLEN(dev),
 786                    dev->net->mtu,
 787                    (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
 788                    (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
 789                    (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
 790                    (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
 791                    (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
 792                    "simple");
 793
 794         // delay posting reads until we're fully open
 795         tasklet_schedule (&dev->bh);
 796         if (info->manage_power) {
 797                 retval = info->manage_power(dev, 1);
 798                 if (retval < 0) {
 799                         retval = 0;
 800                         set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
 801                 } else {
 802                         usb_autopm_put_interface(dev->intf);
 803                 }
 804         }
 805         return retval;
 806 done:
 807         usb_autopm_put_interface(dev->intf);
 808 done_nopm:
 809         return retval;
 810 }
 811 EXPORT_SYMBOL_GPL(usbnet_open);
 812
 813 /*-------------------------------------------------------------------------*/
 814
 815 /* ethtool methods; minidrivers may need to add some more, but
 816  * they'll probably want to use this base set.
 817  */
 818
 819 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
 820 {
 821         struct usbnet *dev = netdev_priv(net);
 822
 823         if (!dev->mii.mdio_read)
 824                 return -EOPNOTSUPP;
 825
 826         return mii_ethtool_gset(&dev->mii, cmd);
 827 }
 828 EXPORT_SYMBOL_GPL(usbnet_get_settings);
 829
 830 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
 831 {
 832         struct usbnet *dev = netdev_priv(net);
 833         int retval;
 834
 835         if (!dev->mii.mdio_write)
 836                 return -EOPNOTSUPP;
 837
 838         retval = mii_ethtool_sset(&dev->mii, cmd);
 839
 840         /* link speed/duplex might have changed */
 841         if (dev->driver_info->link_reset)
 842                 dev->driver_info->link_reset(dev);
 843
 844         return retval;
 845
 846 }
 847 EXPORT_SYMBOL_GPL(usbnet_set_settings);
 848
 849 u32 usbnet_get_link (struct net_device *net)
 850 {
 851         struct usbnet *dev = netdev_priv(net);
 852
 853         /* If a check_connect is defined, return its result */
 854         if (dev->driver_info->check_connect)
 855                 return dev->driver_info->check_connect (dev) == 0;
 856
 857         /* if the device has mii operations, use those */
 858         if (dev->mii.mdio_read)
 859                 return mii_link_ok(&dev->mii);
 860
 861         /* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
 862         return ethtool_op_get_link(net);
 863 }
 864 EXPORT_SYMBOL_GPL(usbnet_get_link);
 865
 866 int usbnet_nway_reset(struct net_device *net)
 867 {
 868         struct usbnet *dev = netdev_priv(net);
 869
 870         if (!dev->mii.mdio_write)
 871                 return -EOPNOTSUPP;
 872
 873         return mii_nway_restart(&dev->mii);
 874 }
 875 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
 876
 877 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
 878 {
 879         struct usbnet *dev = netdev_priv(net);
 880
 881         strlcpy (info->driver, dev->driver_name, sizeof info->driver);
 882         strlcpy (info->version, DRIVER_VERSION, sizeof info->version);
 883         strlcpy (info->fw_version, dev->driver_info->description,
 884                 sizeof info->fw_version);
 885         usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
 886 }
 887 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
 888
 889 u32 usbnet_get_msglevel (struct net_device *net)
 890 {
 891         struct usbnet *dev = netdev_priv(net);
 892
 893         return dev->msg_enable;
 894 }
 895 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
 896
 897 void usbnet_set_msglevel (struct net_device *net, u32 level)
 898 {
 899         struct usbnet *dev = netdev_priv(net);
 900
 901         dev->msg_enable = level;
 902 }
 903 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
 904
 905 /* drivers may override default ethtool_ops in their bind() routine */
 906 static const struct ethtool_ops usbnet_ethtool_ops = {
 907         .get_settings           = usbnet_get_settings,
 908         .set_settings           = usbnet_set_settings,
 909         .get_link               = usbnet_get_link,
 910         .nway_reset             = usbnet_nway_reset,
 911         .get_drvinfo            = usbnet_get_drvinfo,
 912         .get_msglevel           = usbnet_get_msglevel,
 913         .set_msglevel           = usbnet_set_msglevel,
 914         .get_ts_info            = ethtool_op_get_ts_info,
 915 };
 916
 917 /*-------------------------------------------------------------------------*/
 918
 919 /* work that cannot be done in interrupt context uses keventd.
 920  *
 921  * NOTE:  with 2.5 we could do more of this using completion callbacks,
 922  * especially now that control transfers can be queued.
 923  */
 924 static void
 925 kevent (struct work_struct *work)
 926 {
 927         struct usbnet           *dev =
 928                 container_of(work, struct usbnet, kevent);
 929         int                     status;
 930
 931         /* usb_clear_halt() needs a thread context */
 932         if (test_bit (EVENT_TX_HALT, &dev->flags)) {
 933                 unlink_urbs (dev, &dev->txq);
 934                 status = usb_autopm_get_interface(dev->intf);
 935                 if (status < 0)
 936                         goto fail_pipe;
 937                 status = usb_clear_halt (dev->udev, dev->out);
 938                 usb_autopm_put_interface(dev->intf);
 939                 if (status < 0 &&
 940                     status != -EPIPE &&
 941                     status != -ESHUTDOWN) {
 942                         if (netif_msg_tx_err (dev))
 943 fail_pipe:
 944                                 netdev_err(dev->net, "can't clear tx halt, status %d\n",
 945                                            status);
 946                 } else {
 947                         clear_bit (EVENT_TX_HALT, &dev->flags);
 948                         if (status != -ESHUTDOWN)
 949                                 netif_wake_queue (dev->net);
 950                 }
 951         }
 952         if (test_bit (EVENT_RX_HALT, &dev->flags)) {
 953                 unlink_urbs (dev, &dev->rxq);
 954                 status = usb_autopm_get_interface(dev->intf);
 955                 if (status < 0)
 956                         goto fail_halt;
 957                 status = usb_clear_halt (dev->udev, dev->in);
 958                 usb_autopm_put_interface(dev->intf);
 959                 if (status < 0 &&
 960                     status != -EPIPE &&
 961                     status != -ESHUTDOWN) {
 962                         if (netif_msg_rx_err (dev))
 963 fail_halt:
 964                                 netdev_err(dev->net, "can't clear rx halt, status %d\n",
 965                                            status);
 966                 } else {
 967                         clear_bit (EVENT_RX_HALT, &dev->flags);
 968                         tasklet_schedule (&dev->bh);
 969                 }
 970         }
 971
 972         /* tasklet could resubmit itself forever if memory is tight */
 973         if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
 974                 struct urb      *urb = NULL;
 975                 int resched = 1;
 976
 977                 if (netif_running (dev->net))
 978                         urb = usb_alloc_urb (0, GFP_KERNEL);
 979                 else
 980                         clear_bit (EVENT_RX_MEMORY, &dev->flags);
 981                 if (urb != NULL) {
 982                         clear_bit (EVENT_RX_MEMORY, &dev->flags);
 983                         status = usb_autopm_get_interface(dev->intf);
 984                         if (status < 0) {
 985                                 usb_free_urb(urb);
 986                                 goto fail_lowmem;
 987                         }
 988                         if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
 989                                 resched = 0;
 990                         usb_autopm_put_interface(dev->intf);
 991 fail_lowmem:
 992                         if (resched)
 993                                 tasklet_schedule (&dev->bh);
 994                 }
 995         }
 996
 997         if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
 998                 struct driver_info      *info = dev->driver_info;
 999                 int                     retval = 0;
1000
1001                 clear_bit (EVENT_LINK_RESET, &dev->flags);
1002                 status = usb_autopm_get_interface(dev->intf);
1003                 if (status < 0)
1004                         goto skip_reset;
1005                 if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1006                         usb_autopm_put_interface(dev->intf);
1007 skip_reset:
1008                         netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1009                                     retval,
1010                                     dev->udev->bus->bus_name,
1011                                     dev->udev->devpath,
1012                                     info->description);
1013                 } else {
1014                         usb_autopm_put_interface(dev->intf);
1015                 }
1016         }
1017
1018         if (dev->flags)
1019                 netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1020 }
1021
1022 /*-------------------------------------------------------------------------*/
1023
1024 static void tx_complete (struct urb *urb)
1025 {
1026         struct sk_buff          *skb = (struct sk_buff *) urb->context;
1027         struct skb_data         *entry = (struct skb_data *) skb->cb;
1028         struct usbnet           *dev = entry->dev;
1029
1030         if (urb->status == 0) {
1031                 if (!(dev->driver_info->flags & FLAG_MULTI_PACKET))
1032                         dev->net->stats.tx_packets++;
1033                 dev->net->stats.tx_bytes += entry->length;
1034         } else {
1035                 dev->net->stats.tx_errors++;
1036
1037                 switch (urb->status) {
1038                 case -EPIPE:
1039                         usbnet_defer_kevent (dev, EVENT_TX_HALT);
1040                         break;
1041
1042                 /* software-driven interface shutdown */
1043                 case -ECONNRESET:               // async unlink
1044                 case -ESHUTDOWN:                // hardware gone
1045                         break;
1046
1047                 // like rx, tx gets controller i/o faults during khubd delays
1048                 // and so it uses the same throttling mechanism.
1049                 case -EPROTO:
1050                 case -ETIME:
1051                 case -EILSEQ:
1052                         usb_mark_last_busy(dev->udev);
1053                         if (!timer_pending (&dev->delay)) {
1054                                 mod_timer (&dev->delay,
1055                                         jiffies + THROTTLE_JIFFIES);
1056                                 netif_dbg(dev, link, dev->net,
1057                                           "tx throttle %d\n", urb->status);
1058                         }
1059                         netif_stop_queue (dev->net);
1060                         break;
1061                 default:
1062                         netif_dbg(dev, tx_err, dev->net,
1063                                   "tx err %d\n", entry->urb->status);
1064                         break;
1065                 }
1066         }
1067
1068         usb_autopm_put_interface_async(dev->intf);
1069         (void) defer_bh(dev, skb, &dev->txq, tx_done);
1070 }
1071
1072 /*-------------------------------------------------------------------------*/
1073
1074 void usbnet_tx_timeout (struct net_device *net)
1075 {
1076         struct usbnet           *dev = netdev_priv(net);
1077
1078         unlink_urbs (dev, &dev->txq);
1079         tasklet_schedule (&dev->bh);
1080
1081         // FIXME: device recovery -- reset?
1082 }
1083 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1084
1085 /*-------------------------------------------------------------------------*/
1086
1087 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1088                                      struct net_device *net)
1089 {
1090         struct usbnet           *dev = netdev_priv(net);
1091         int                     length;
1092         struct urb              *urb = NULL;
1093         struct skb_data         *entry;
1094         struct driver_info      *info = dev->driver_info;
1095         unsigned long           flags;
1096         int retval;
1097
1098         if (skb)
1099                 skb_tx_timestamp(skb);
1100
1101         // some devices want funky USB-level framing, for
1102         // win32 driver (usually) and/or hardware quirks
1103         if (info->tx_fixup) {
1104                 skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1105                 if (!skb) {
1106                         if (netif_msg_tx_err(dev)) {
1107                                 netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1108                                 goto drop;
1109                         } else {
1110                                 /* cdc_ncm collected packet; waits for more */
1111                                 goto not_drop;
1112                         }
1113                 }
1114         }
1115         length = skb->len;
1116
1117         if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1118                 netif_dbg(dev, tx_err, dev->net, "no urb\n");
1119                 goto drop;
1120         }
1121
1122         entry = (struct skb_data *) skb->cb;
1123         entry->urb = urb;
1124         entry->dev = dev;
1125         entry->length = length;
1126
1127         usb_fill_bulk_urb (urb, dev->udev, dev->out,
1128                         skb->data, skb->len, tx_complete, skb);
1129
1130         /* don't assume the hardware handles USB_ZERO_PACKET
1131          * NOTE:  strictly conforming cdc-ether devices should expect
1132          * the ZLP here, but ignore the one-byte packet.
1133          * NOTE2: CDC NCM specification is different from CDC ECM when
1134          * handling ZLP/short packets, so cdc_ncm driver will make short
1135          * packet itself if needed.
1136          */
1137         if (length % dev->maxpacket == 0) {
1138                 if (!(info->flags & FLAG_SEND_ZLP)) {
1139                         if (!(info->flags & FLAG_MULTI_PACKET)) {
1140                                 urb->transfer_buffer_length++;
1141                                 if (skb_tailroom(skb)) {
1142                                         skb->data[skb->len] = 0;
1143                                         __skb_put(skb, 1);
1144                                 }
1145                         }
1146                 } else
1147                         urb->transfer_flags |= URB_ZERO_PACKET;
1148         }
1149
1150         spin_lock_irqsave(&dev->txq.lock, flags);
1151         retval = usb_autopm_get_interface_async(dev->intf);
1152         if (retval < 0) {
1153                 spin_unlock_irqrestore(&dev->txq.lock, flags);
1154                 goto drop;
1155         }
1156
1157 #ifdef CONFIG_PM
1158         /* if this triggers the device is still a sleep */
1159         if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1160                 /* transmission will be done in resume */
1161                 usb_anchor_urb(urb, &dev->deferred);
1162                 /* no use to process more packets */
1163                 netif_stop_queue(net);
1164                 usb_put_urb(urb);
1165                 spin_unlock_irqrestore(&dev->txq.lock, flags);
1166                 netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1167                 goto deferred;
1168         }
1169 #endif
1170
1171         switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1172         case -EPIPE:
1173                 netif_stop_queue (net);
1174                 usbnet_defer_kevent (dev, EVENT_TX_HALT);
1175                 usb_autopm_put_interface_async(dev->intf);
1176                 break;
1177         default:
1178                 usb_autopm_put_interface_async(dev->intf);
1179                 netif_dbg(dev, tx_err, dev->net,
1180                           "tx: submit urb err %d\n", retval);
1181                 break;
1182         case 0:
1183                 net->trans_start = jiffies;
1184                 __usbnet_queue_skb(&dev->txq, skb, tx_start);
1185                 if (dev->txq.qlen >= TX_QLEN (dev))
1186                         netif_stop_queue (net);
1187         }
1188         spin_unlock_irqrestore (&dev->txq.lock, flags);
1189
1190         if (retval) {
1191                 netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1192 drop:
1193                 dev->net->stats.tx_dropped++;
1194 not_drop:
1195                 if (skb)
1196                         dev_kfree_skb_any (skb);
1197                 usb_free_urb (urb);
1198         } else
1199                 netif_dbg(dev, tx_queued, dev->net,
1200                           "> tx, len %d, type 0x%x\n", length, skb->protocol);
1201 #ifdef CONFIG_PM
1202 deferred:
1203 #endif
1204         return NETDEV_TX_OK;
1205 }
1206 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1207
1208 static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1209 {
1210         struct urb      *urb;
1211         int             i;
1212         int             ret = 0;
1213
1214         /* don't refill the queue all at once */
1215         for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1216                 urb = usb_alloc_urb(0, flags);
1217                 if (urb != NULL) {
1218                         ret = rx_submit(dev, urb, flags);
1219                         if (ret)
1220                                 goto err;
1221                 } else {
1222                         ret = -ENOMEM;
1223                         goto err;
1224                 }
1225         }
1226 err:
1227         return ret;
1228 }
1229
1230 /*-------------------------------------------------------------------------*/
1231
1232 // tasklet (work deferred from completions, in_irq) or timer
1233
1234 static void usbnet_bh (unsigned long param)
1235 {
1236         struct usbnet           *dev = (struct usbnet *) param;
1237         struct sk_buff          *skb;
1238         struct skb_data         *entry;
1239
1240         while ((skb = skb_dequeue (&dev->done))) {
1241                 entry = (struct skb_data *) skb->cb;
1242                 switch (entry->state) {
1243                 case rx_done:
1244                         entry->state = rx_cleanup;
1245                         rx_process (dev, skb);
1246                         continue;
1247                 case tx_done:
1248                 case rx_cleanup:
1249                         usb_free_urb (entry->urb);
1250                         dev_kfree_skb (skb);
1251                         continue;
1252                 default:
1253                         netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1254                 }
1255         }
1256
1257         // waiting for all pending urbs to complete?
1258         if (dev->wait) {
1259                 if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
1260                         wake_up (dev->wait);
1261                 }
1262
1263         // or are we maybe short a few urbs?
1264         } else if (netif_running (dev->net) &&
1265                    netif_device_present (dev->net) &&
1266                    !timer_pending (&dev->delay) &&
1267                    !test_bit (EVENT_RX_HALT, &dev->flags)) {
1268                 int     temp = dev->rxq.qlen;
1269
1270                 if (temp < RX_QLEN(dev)) {
1271                         if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1272                                 return;
1273                         if (temp != dev->rxq.qlen)
1274                                 netif_dbg(dev, link, dev->net,
1275                                           "rxqlen %d --> %d\n",
1276                                           temp, dev->rxq.qlen);
1277                         if (dev->rxq.qlen < RX_QLEN(dev))
1278                                 tasklet_schedule (&dev->bh);
1279                 }
1280                 if (dev->txq.qlen < TX_QLEN (dev))
1281                         netif_wake_queue (dev->net);
1282         }
1283 }
1284
1285
1286 /*-------------------------------------------------------------------------
1287  *
1288  * USB Device Driver support
1289  *
1290  *-------------------------------------------------------------------------*/
1291
1292 // precondition: never called in_interrupt
1293
1294 void usbnet_disconnect (struct usb_interface *intf)
1295 {
1296         struct usbnet           *dev;
1297         struct usb_device       *xdev;
1298         struct net_device       *net;
1299
1300         dev = usb_get_intfdata(intf);
1301         usb_set_intfdata(intf, NULL);
1302         if (!dev)
1303                 return;
1304
1305         xdev = interface_to_usbdev (intf);
1306
1307         netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1308                    intf->dev.driver->name,
1309                    xdev->bus->bus_name, xdev->devpath,
1310                    dev->driver_info->description);
1311
1312         net = dev->net;
1313         unregister_netdev (net);
1314
1315         cancel_work_sync(&dev->kevent);
1316
1317         usb_scuttle_anchored_urbs(&dev->deferred);
1318
1319         if (dev->driver_info->unbind)
1320                 dev->driver_info->unbind (dev, intf);
1321
1322         usb_kill_urb(dev->interrupt);
1323         usb_free_urb(dev->interrupt);
1324
1325         free_netdev(net);
1326 }
1327 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1328
1329 static const struct net_device_ops usbnet_netdev_ops = {
1330         .ndo_open               = usbnet_open,
1331         .ndo_stop               = usbnet_stop,
1332         .ndo_start_xmit         = usbnet_start_xmit,
1333         .ndo_tx_timeout         = usbnet_tx_timeout,
1334         .ndo_change_mtu         = usbnet_change_mtu,
1335         .ndo_set_mac_address    = eth_mac_addr,
1336         .ndo_validate_addr      = eth_validate_addr,
1337 };
1338
1339 /*-------------------------------------------------------------------------*/
1340
1341 // precondition: never called in_interrupt
1342
1343 static struct device_type wlan_type = {
1344         .name   = "wlan",
1345 };
1346
1347 static struct device_type wwan_type = {
1348         .name   = "wwan",
1349 };
1350
1351 int
1352 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1353 {
1354         struct usbnet                   *dev;
1355         struct net_device               *net;
1356         struct usb_host_interface       *interface;
1357         struct driver_info              *info;
1358         struct usb_device               *xdev;
1359         int                             status;
1360         const char                      *name;
1361         struct usb_driver       *driver = to_usb_driver(udev->dev.driver);
1362
1363         /* usbnet already took usb runtime pm, so have to enable the feature
1364          * for usb interface, otherwise usb_autopm_get_interface may return
1365          * failure if USB_SUSPEND(RUNTIME_PM) is enabled.
1366          */
1367         if (!driver->supports_autosuspend) {
1368                 driver->supports_autosuspend = 1;
1369                 pm_runtime_enable(&udev->dev);
1370         }
1371
1372         name = udev->dev.driver->name;
1373         info = (struct driver_info *) prod->driver_info;
1374         if (!info) {
1375                 dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1376                 return -ENODEV;
1377         }
1378         xdev = interface_to_usbdev (udev);
1379         interface = udev->cur_altsetting;
1380
1381         status = -ENOMEM;
1382
1383         // set up our own records
1384         net = alloc_etherdev(sizeof(*dev));
1385         if (!net)
1386                 goto out;
1387
1388         /* netdev_printk() needs this so do it as early as possible */
1389         SET_NETDEV_DEV(net, &udev->dev);
1390
1391         dev = netdev_priv(net);
1392         dev->udev = xdev;
1393         dev->intf = udev;
1394         dev->driver_info = info;
1395         dev->driver_name = name;
1396         dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1397                                 | NETIF_MSG_PROBE | NETIF_MSG_LINK);
1398         skb_queue_head_init (&dev->rxq);
1399         skb_queue_head_init (&dev->txq);
1400         skb_queue_head_init (&dev->done);
1401         skb_queue_head_init(&dev->rxq_pause);
1402         dev->bh.func = usbnet_bh;
1403         dev->bh.data = (unsigned long) dev;
1404         INIT_WORK (&dev->kevent, kevent);
1405         init_usb_anchor(&dev->deferred);
1406         dev->delay.function = usbnet_bh;
1407         dev->delay.data = (unsigned long) dev;
1408         init_timer (&dev->delay);
1409         mutex_init (&dev->phy_mutex);
1410
1411         dev->net = net;
1412         strcpy (net->name, "usb%d");
1413         memcpy (net->dev_addr, node_id, sizeof node_id);
1414
1415         /* rx and tx sides can use different message sizes;
1416          * bind() should set rx_urb_size in that case.
1417          */
1418         dev->hard_mtu = net->mtu + net->hard_header_len;
1419 #if 0
1420 // dma_supported() is deeply broken on almost all architectures
1421         // possible with some EHCI controllers
1422         if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1423                 net->features |= NETIF_F_HIGHDMA;
1424 #endif
1425
1426         net->netdev_ops = &usbnet_netdev_ops;
1427         net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1428         net->ethtool_ops = &usbnet_ethtool_ops;
1429
1430         // allow device-specific bind/init procedures
1431         // NOTE net->name still not usable ...
1432         if (info->bind) {
1433                 status = info->bind (dev, udev);
1434                 if (status < 0)
1435                         goto out1;
1436
1437                 // heuristic:  "usb%d" for links we know are two-host,
1438                 // else "eth%d" when there's reasonable doubt.  userspace
1439                 // can rename the link if it knows better.
1440                 if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1441                     ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1442                      (net->dev_addr [0] & 0x02) == 0))
1443                         strcpy (net->name, "eth%d");
1444                 /* WLAN devices should always be named "wlan%d" */
1445                 if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1446                         strcpy(net->name, "wlan%d");
1447                 /* WWAN devices should always be named "wwan%d" */
1448                 if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1449                         strcpy(net->name, "wwan%d");
1450
1451                 /* maybe the remote can't receive an Ethernet MTU */
1452                 if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1453                         net->mtu = dev->hard_mtu - net->hard_header_len;
1454         } else if (!info->in || !info->out)
1455                 status = usbnet_get_endpoints (dev, udev);
1456         else {
1457                 dev->in = usb_rcvbulkpipe (xdev, info->in);
1458                 dev->out = usb_sndbulkpipe (xdev, info->out);
1459                 if (!(info->flags & FLAG_NO_SETINT))
1460                         status = usb_set_interface (xdev,
1461                                 interface->desc.bInterfaceNumber,
1462                                 interface->desc.bAlternateSetting);
1463                 else
1464                         status = 0;
1465
1466         }
1467         if (status >= 0 && dev->status)
1468                 status = init_status (dev, udev);
1469         if (status < 0)
1470                 goto out3;
1471
1472         if (!dev->rx_urb_size)
1473                 dev->rx_urb_size = dev->hard_mtu;
1474         dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1475
1476         if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1477                 SET_NETDEV_DEVTYPE(net, &wlan_type);
1478         if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1479                 SET_NETDEV_DEVTYPE(net, &wwan_type);
1480
1481         status = register_netdev (net);
1482         if (status)
1483                 goto out4;
1484         netif_info(dev, probe, dev->net,
1485                    "register '%s' at usb-%s-%s, %s, %pM\n",
1486                    udev->dev.driver->name,
1487                    xdev->bus->bus_name, xdev->devpath,
1488                    dev->driver_info->description,
1489                    net->dev_addr);
1490
1491         // ok, it's ready to go.
1492         usb_set_intfdata (udev, dev);
1493
1494         netif_device_attach (net);
1495
1496         if (dev->driver_info->flags & FLAG_LINK_INTR)
1497                 netif_carrier_off(net);
1498
1499         return 0;
1500
1501 out4:
1502         usb_free_urb(dev->interrupt);
1503 out3:
1504         if (info->unbind)
1505                 info->unbind (dev, udev);
1506 out1:
1507         free_netdev(net);
1508 out:
1509         return status;
1510 }
1511 EXPORT_SYMBOL_GPL(usbnet_probe);
1512
1513 /*-------------------------------------------------------------------------*/
1514
1515 /*
1516  * suspend the whole driver as soon as the first interface is suspended
1517  * resume only when the last interface is resumed
1518  */
1519
1520 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1521 {
1522         struct usbnet           *dev = usb_get_intfdata(intf);
1523
1524         if (!dev->suspend_count++) {
1525                 spin_lock_irq(&dev->txq.lock);
1526                 /* don't autosuspend while transmitting */
1527                 if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1528                         dev->suspend_count--;
1529                         spin_unlock_irq(&dev->txq.lock);
1530                         return -EBUSY;
1531                 } else {
1532                         set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1533                         spin_unlock_irq(&dev->txq.lock);
1534                 }
1535                 /*
1536                  * accelerate emptying of the rx and queues, to avoid
1537                  * having everything error out.
1538                  */
1539                 netif_device_detach (dev->net);
1540                 usbnet_terminate_urbs(dev);
1541                 usb_kill_urb(dev->interrupt);
1542
1543                 /*
1544                  * reattach so runtime management can use and
1545                  * wake the device
1546                  */
1547                 netif_device_attach (dev->net);
1548         }
1549         return 0;
1550 }
1551 EXPORT_SYMBOL_GPL(usbnet_suspend);
1552
1553 int usbnet_resume (struct usb_interface *intf)
1554 {
1555         struct usbnet           *dev = usb_get_intfdata(intf);
1556         struct sk_buff          *skb;
1557         struct urb              *res;
1558         int                     retval;
1559
1560         if (!--dev->suspend_count) {
1561                 /* resume interrupt URBs */
1562                 if (dev->interrupt && test_bit(EVENT_DEV_OPEN, &dev->flags))
1563                         usb_submit_urb(dev->interrupt, GFP_NOIO);
1564
1565                 spin_lock_irq(&dev->txq.lock);
1566                 while ((res = usb_get_from_anchor(&dev->deferred))) {
1567
1568                         skb = (struct sk_buff *)res->context;
1569                         retval = usb_submit_urb(res, GFP_ATOMIC);
1570                         if (retval < 0) {
1571                                 dev_kfree_skb_any(skb);
1572                                 usb_free_urb(res);
1573                                 usb_autopm_put_interface_async(dev->intf);
1574                         } else {
1575                                 dev->net->trans_start = jiffies;
1576                                 __skb_queue_tail(&dev->txq, skb);
1577                         }
1578                 }
1579
1580                 smp_mb();
1581                 clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1582                 spin_unlock_irq(&dev->txq.lock);
1583
1584                 if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1585                         /* handle remote wakeup ASAP */
1586                         if (!dev->wait &&
1587                                 netif_device_present(dev->net) &&
1588                                 !timer_pending(&dev->delay) &&
1589                                 !test_bit(EVENT_RX_HALT, &dev->flags))
1590                                         rx_alloc_submit(dev, GFP_NOIO);
1591
1592                         if (!(dev->txq.qlen >= TX_QLEN(dev)))
1593                                 netif_tx_wake_all_queues(dev->net);
1594                         tasklet_schedule (&dev->bh);
1595                 }
1596         }
1597
1598         if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1599                 usb_autopm_get_interface_no_resume(intf);
1600
1601         return 0;
1602 }
1603 EXPORT_SYMBOL_GPL(usbnet_resume);
1604
1605 /*
1606  * Either a subdriver implements manage_power, then it is assumed to always
1607  * be ready to be suspended or it reports the readiness to be suspended
1608  * explicitly
1609  */
1610 void usbnet_device_suggests_idle(struct usbnet *dev)
1611 {
1612         if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1613                 dev->intf->needs_remote_wakeup = 1;
1614                 usb_autopm_put_interface_async(dev->intf);
1615         }
1616 }
1617 EXPORT_SYMBOL(usbnet_device_suggests_idle);
1618
1619 /*-------------------------------------------------------------------------*/
1620 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1621                              u16 value, u16 index, void *data, u16 size)
1622 {
1623         void *buf = NULL;
1624         int err = -ENOMEM;
1625
1626         netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
1627                    " value=0x%04x index=0x%04x size=%d\n",
1628                    cmd, reqtype, value, index, size);
1629
1630         if (data) {
1631                 buf = kmalloc(size, GFP_KERNEL);
1632                 if (!buf)
1633                         goto out;
1634         }
1635
1636         err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
1637                               cmd, reqtype, value, index, buf, size,
1638                               USB_CTRL_GET_TIMEOUT);
1639         if (err > 0 && err <= size)
1640                 memcpy(data, buf, err);
1641         kfree(buf);
1642 out:
1643         return err;
1644 }
1645
1646 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1647                               u16 value, u16 index, const void *data,
1648                               u16 size)
1649 {
1650         void *buf = NULL;
1651         int err = -ENOMEM;
1652
1653         netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
1654                    " value=0x%04x index=0x%04x size=%d\n",
1655                    cmd, reqtype, value, index, size);
1656
1657         if (data) {
1658                 buf = kmemdup(data, size, GFP_KERNEL);
1659                 if (!buf)
1660                         goto out;
1661         }
1662
1663         err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
1664                               cmd, reqtype, value, index, buf, size,
1665                               USB_CTRL_SET_TIMEOUT);
1666         kfree(buf);
1667
1668 out:
1669         return err;
1670 }
1671
1672 /*
1673  * The function can't be called inside suspend/resume callback,
1674  * otherwise deadlock will be caused.
1675  */
1676 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1677                     u16 value, u16 index, void *data, u16 size)
1678 {
1679         int ret;
1680
1681         if (usb_autopm_get_interface(dev->intf) < 0)
1682                 return -ENODEV;
1683         ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
1684                                 data, size);
1685         usb_autopm_put_interface(dev->intf);
1686         return ret;
1687 }
1688 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
1689
1690 /*
1691  * The function can't be called inside suspend/resume callback,
1692  * otherwise deadlock will be caused.
1693  */
1694 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1695                      u16 value, u16 index, const void *data, u16 size)
1696 {
1697         int ret;
1698
1699         if (usb_autopm_get_interface(dev->intf) < 0)
1700                 return -ENODEV;
1701         ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
1702                                  data, size);
1703         usb_autopm_put_interface(dev->intf);
1704         return ret;
1705 }
1706 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
1707
1708 /*
1709  * The function can be called inside suspend/resume callback safely
1710  * and should only be called by suspend/resume callback generally.
1711  */
1712 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
1713                           u16 value, u16 index, void *data, u16 size)
1714 {
1715         return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
1716                                  data, size);
1717 }
1718 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
1719
1720 /*
1721  * The function can be called inside suspend/resume callback safely
1722  * and should only be called by suspend/resume callback generally.
1723  */
1724 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
1725                           u16 value, u16 index, const void *data,
1726                           u16 size)
1727 {
1728         return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
1729                                   data, size);
1730 }
1731 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
1732
1733 static void usbnet_async_cmd_cb(struct urb *urb)
1734 {
1735         struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
1736         int status = urb->status;
1737
1738         if (status < 0)
1739                 dev_dbg(&urb->dev->dev, "%s failed with %d",
1740                         __func__, status);
1741
1742         kfree(req);
1743         usb_free_urb(urb);
1744 }
1745
1746 /*
1747  * The caller must make sure that device can't be put into suspend
1748  * state until the control URB completes.
1749  */
1750 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
1751                            u16 value, u16 index, const void *data, u16 size)
1752 {
1753         struct usb_ctrlrequest *req = NULL;
1754         struct urb *urb;
1755         int err = -ENOMEM;
1756         void *buf = NULL;
1757
1758         netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
1759                    " value=0x%04x index=0x%04x size=%d\n",
1760                    cmd, reqtype, value, index, size);
1761
1762         urb = usb_alloc_urb(0, GFP_ATOMIC);
1763         if (!urb) {
1764                 netdev_err(dev->net, "Error allocating URB in"
1765                            " %s!\n", __func__);
1766                 goto fail;
1767         }
1768
1769         if (data) {
1770                 buf = kmemdup(data, size, GFP_ATOMIC);
1771                 if (!buf) {
1772                         netdev_err(dev->net, "Error allocating buffer"
1773                                    " in %s!\n", __func__);
1774                         goto fail_free;
1775                 }
1776         }
1777
1778         req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
1779         if (!req) {
1780                 netdev_err(dev->net, "Failed to allocate memory for %s\n",
1781                            __func__);
1782                 goto fail_free_buf;
1783         }
1784
1785         req->bRequestType = reqtype;
1786         req->bRequest = cmd;
1787         req->wValue = cpu_to_le16(value);
1788         req->wIndex = cpu_to_le16(index);
1789         req->wLength = cpu_to_le16(size);
1790
1791         usb_fill_control_urb(urb, dev->udev,
1792                              usb_sndctrlpipe(dev->udev, 0),
1793                              (void *)req, buf, size,
1794                              usbnet_async_cmd_cb, req);
1795         urb->transfer_flags |= URB_FREE_BUFFER;
1796
1797         err = usb_submit_urb(urb, GFP_ATOMIC);
1798         if (err < 0) {
1799                 netdev_err(dev->net, "Error submitting the control"
1800                            " message: status=%d\n", err);
1801                 goto fail_free;
1802         }
1803         return 0;
1804
1805 fail_free_buf:
1806         kfree(buf);
1807 fail_free:
1808         kfree(req);
1809         usb_free_urb(urb);
1810 fail:
1811         return err;
1812
1813 }
1814 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
1815 /*-------------------------------------------------------------------------*/
1816
1817 static int __init usbnet_init(void)
1818 {
1819         /* Compiler should optimize this out. */
1820         BUILD_BUG_ON(
1821                 FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
1822
1823         eth_random_addr(node_id);
1824         return 0;
1825 }
1826 module_init(usbnet_init);
1827
1828 static void __exit usbnet_exit(void)
1829 {
1830 }
1831 module_exit(usbnet_exit);
1832
1833 MODULE_AUTHOR("David Brownell");
1834 MODULE_DESCRIPTION("USB network driver framework");
1835 MODULE_LICENSE("GPL");