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 static int init_status (struct usbnet *dev, struct usb_interface *intf)
 186 {
 187         char            *buf = NULL;
 188         unsigned        pipe = 0;
 189         unsigned        maxp;
 190         unsigned        period;
 191
 192         if (!dev->driver_info->status)
 193                 return 0;
 194
 195         pipe = usb_rcvintpipe (dev->udev,
 196                         dev->status->desc.bEndpointAddress
 197                                 & USB_ENDPOINT_NUMBER_MASK);
 198         maxp = usb_maxpacket (dev->udev, pipe, 0);
 199
 200         /* avoid 1 msec chatter:  min 8 msec poll rate */
 201         period = max ((int) dev->status->desc.bInterval,
 202                 (dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
 203
 204         buf = kmalloc (maxp, GFP_KERNEL);
 205         if (buf) {
 206                 dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
 207                 if (!dev->interrupt) {
 208                         kfree (buf);
 209                         return -ENOMEM;
 210                 } else {
 211                         usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
 212                                 buf, maxp, intr_complete, dev, period);
 213                         dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
 214                         dev_dbg(&intf->dev,
 215                                 "status ep%din, %d bytes period %d\n",
 216                                 usb_pipeendpoint(pipe), maxp, period);
 217                 }
 218         }
 219         return 0;
 220 }
 221
 222 /* Passes this packet up the stack, updating its accounting.
 223  * Some link protocols batch packets, so their rx_fixup paths
 224  * can return clones as well as just modify the original skb.
 225  */
 226 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
 227 {
 228         int     status;
 229
 230         if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
 231                 skb_queue_tail(&dev->rxq_pause, skb);
 232                 return;
 233         }
 234
 235         skb->protocol = eth_type_trans (skb, dev->net);
 236         dev->net->stats.rx_packets++;
 237         dev->net->stats.rx_bytes += skb->len;
 238
 239         netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
 240                   skb->len + sizeof (struct ethhdr), skb->protocol);
 241         memset (skb->cb, 0, sizeof (struct skb_data));
 242
 243         if (skb_defer_rx_timestamp(skb))
 244                 return;
 245
 246         status = netif_rx (skb);
 247         if (status != NET_RX_SUCCESS)
 248                 netif_dbg(dev, rx_err, dev->net,
 249                           "netif_rx status %d\n", status);
 250 }
 251 EXPORT_SYMBOL_GPL(usbnet_skb_return);
 252
 253 \f
 254 /*-------------------------------------------------------------------------
 255  *
 256  * Network Device Driver (peer link to "Host Device", from USB host)
 257  *
 258  *-------------------------------------------------------------------------*/
 259
 260 int usbnet_change_mtu (struct net_device *net, int new_mtu)
 261 {
 262         struct usbnet   *dev = netdev_priv(net);
 263         int             ll_mtu = new_mtu + net->hard_header_len;
 264         int             old_hard_mtu = dev->hard_mtu;
 265         int             old_rx_urb_size = dev->rx_urb_size;
 266
 267         if (new_mtu <= 0)
 268                 return -EINVAL;
 269         // no second zero-length packet read wanted after mtu-sized packets
 270         if ((ll_mtu % dev->maxpacket) == 0)
 271                 return -EDOM;
 272         net->mtu = new_mtu;
 273
 274         dev->hard_mtu = net->mtu + net->hard_header_len;
 275         if (dev->rx_urb_size == old_hard_mtu) {
 276                 dev->rx_urb_size = dev->hard_mtu;
 277                 if (dev->rx_urb_size > old_rx_urb_size)
 278                         usbnet_unlink_rx_urbs(dev);
 279         }
 280
 281         return 0;
 282 }
 283 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
 284
 285 /* The caller must hold list->lock */
 286 static void __usbnet_queue_skb(struct sk_buff_head *list,
 287                         struct sk_buff *newsk, enum skb_state state)
 288 {
 289         struct skb_data *entry = (struct skb_data *) newsk->cb;
 290
 291         __skb_queue_tail(list, newsk);
 292         entry->state = state;
 293 }
 294
 295 /*-------------------------------------------------------------------------*/
 296
 297 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
 298  * completion callbacks.  2.5 should have fixed those bugs...
 299  */
 300
 301 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
 302                 struct sk_buff_head *list, enum skb_state state)
 303 {
 304         unsigned long           flags;
 305         enum skb_state          old_state;
 306         struct skb_data *entry = (struct skb_data *) skb->cb;
 307
 308         spin_lock_irqsave(&list->lock, flags);
 309         old_state = entry->state;
 310         entry->state = state;
 311         __skb_unlink(skb, list);
 312         spin_unlock(&list->lock);
 313         spin_lock(&dev->done.lock);
 314         __skb_queue_tail(&dev->done, skb);
 315         if (dev->done.qlen == 1)
 316                 tasklet_schedule(&dev->bh);
 317         spin_unlock_irqrestore(&dev->done.lock, flags);
 318         return old_state;
 319 }
 320
 321 /* some work can't be done in tasklets, so we use keventd
 322  *
 323  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
 324  * but tasklet_schedule() doesn't.  hope the failure is rare.
 325  */
 326 void usbnet_defer_kevent (struct usbnet *dev, int work)
 327 {
 328         set_bit (work, &dev->flags);
 329         if (!schedule_work (&dev->kevent))
 330                 netdev_err(dev->net, "kevent %d may have been dropped\n", work);
 331         else
 332                 netdev_dbg(dev->net, "kevent %d scheduled\n", work);
 333 }
 334 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
 335
 336 /*-------------------------------------------------------------------------*/
 337
 338 static void rx_complete (struct urb *urb);
 339
 340 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
 341 {
 342         struct sk_buff          *skb;
 343         struct skb_data         *entry;
 344         int                     retval = 0;
 345         unsigned long           lockflags;
 346         size_t                  size = dev->rx_urb_size;
 347
 348         skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
 349         if (!skb) {
 350                 netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
 351                 usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
 352                 usb_free_urb (urb);
 353                 return -ENOMEM;
 354         }
 355
 356         entry = (struct skb_data *) skb->cb;
 357         entry->urb = urb;
 358         entry->dev = dev;
 359         entry->length = 0;
 360
 361         usb_fill_bulk_urb (urb, dev->udev, dev->in,
 362                 skb->data, size, rx_complete, skb);
 363
 364         spin_lock_irqsave (&dev->rxq.lock, lockflags);
 365
 366         if (netif_running (dev->net) &&
 367             netif_device_present (dev->net) &&
 368             !test_bit (EVENT_RX_HALT, &dev->flags) &&
 369             !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
 370                 switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
 371                 case -EPIPE:
 372                         usbnet_defer_kevent (dev, EVENT_RX_HALT);
 373                         break;
 374                 case -ENOMEM:
 375                         usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
 376                         break;
 377                 case -ENODEV:
 378                         netif_dbg(dev, ifdown, dev->net, "device gone\n");
 379                         netif_device_detach (dev->net);
 380                         break;
 381                 case -EHOSTUNREACH:
 382                         retval = -ENOLINK;
 383                         break;
 384                 default:
 385                         netif_dbg(dev, rx_err, dev->net,
 386                                   "rx submit, %d\n", retval);
 387                         tasklet_schedule (&dev->bh);
 388                         break;
 389                 case 0:
 390                         __usbnet_queue_skb(&dev->rxq, skb, rx_start);
 391                 }
 392         } else {
 393                 netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
 394                 retval = -ENOLINK;
 395         }
 396         spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
 397         if (retval) {
 398                 dev_kfree_skb_any (skb);
 399                 usb_free_urb (urb);
 400         }
 401         return retval;
 402 }
 403
 404
 405 /*-------------------------------------------------------------------------*/
 406
 407 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
 408 {
 409         if (dev->driver_info->rx_fixup &&
 410             !dev->driver_info->rx_fixup (dev, skb)) {
 411                 /* With RX_ASSEMBLE, rx_fixup() must update counters */
 412                 if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
 413                         dev->net->stats.rx_errors++;
 414                 goto done;
 415         }
 416         // else network stack removes extra byte if we forced a short packet
 417
 418         if (skb->len) {
 419                 /* all data was already cloned from skb inside the driver */
 420                 if (dev->driver_info->flags & FLAG_MULTI_PACKET)
 421                         dev_kfree_skb_any(skb);
 422                 else
 423                         usbnet_skb_return(dev, skb);
 424                 return;
 425         }
 426
 427         netif_dbg(dev, rx_err, dev->net, "drop\n");
 428         dev->net->stats.rx_errors++;
 429 done:
 430         skb_queue_tail(&dev->done, skb);
 431 }
 432
 433 /*-------------------------------------------------------------------------*/
 434
 435 static void rx_complete (struct urb *urb)
 436 {
 437         struct sk_buff          *skb = (struct sk_buff *) urb->context;
 438         struct skb_data         *entry = (struct skb_data *) skb->cb;
 439         struct usbnet           *dev = entry->dev;
 440         int                     urb_status = urb->status;
 441         enum skb_state          state;
 442
 443         skb_put (skb, urb->actual_length);
 444         state = rx_done;
 445         entry->urb = NULL;
 446
 447         switch (urb_status) {
 448         /* success */
 449         case 0:
 450                 if (skb->len < dev->net->hard_header_len) {
 451                         state = rx_cleanup;
 452                         dev->net->stats.rx_errors++;
 453                         dev->net->stats.rx_length_errors++;
 454                         netif_dbg(dev, rx_err, dev->net,
 455                                   "rx length %d\n", skb->len);
 456                 }
 457                 break;
 458
 459         /* stalls need manual reset. this is rare ... except that
 460          * when going through USB 2.0 TTs, unplug appears this way.
 461          * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
 462          * storm, recovering as needed.
 463          */
 464         case -EPIPE:
 465                 dev->net->stats.rx_errors++;
 466                 usbnet_defer_kevent (dev, EVENT_RX_HALT);
 467                 // FALLTHROUGH
 468
 469         /* software-driven interface shutdown */
 470         case -ECONNRESET:               /* async unlink */
 471         case -ESHUTDOWN:                /* hardware gone */
 472                 netif_dbg(dev, ifdown, dev->net,
 473                           "rx shutdown, code %d\n", urb_status);
 474                 goto block;
 475
 476         /* we get controller i/o faults during khubd disconnect() delays.
 477          * throttle down resubmits, to avoid log floods; just temporarily,
 478          * so we still recover when the fault isn't a khubd delay.
 479          */
 480         case -EPROTO:
 481         case -ETIME:
 482         case -EILSEQ:
 483                 dev->net->stats.rx_errors++;
 484                 if (!timer_pending (&dev->delay)) {
 485                         mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
 486                         netif_dbg(dev, link, dev->net,
 487                                   "rx throttle %d\n", urb_status);
 488                 }
 489 block:
 490                 state = rx_cleanup;
 491                 entry->urb = urb;
 492                 urb = NULL;
 493                 break;
 494
 495         /* data overrun ... flush fifo? */
 496         case -EOVERFLOW:
 497                 dev->net->stats.rx_over_errors++;
 498                 // FALLTHROUGH
 499
 500         default:
 501                 state = rx_cleanup;
 502                 dev->net->stats.rx_errors++;
 503                 netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
 504                 break;
 505         }
 506
 507         state = defer_bh(dev, skb, &dev->rxq, state);
 508
 509         if (urb) {
 510                 if (netif_running (dev->net) &&
 511                     !test_bit (EVENT_RX_HALT, &dev->flags) &&
 512                     state != unlink_start) {
 513                         rx_submit (dev, urb, GFP_ATOMIC);
 514                         usb_mark_last_busy(dev->udev);
 515                         return;
 516                 }
 517                 usb_free_urb (urb);
 518         }
 519         netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
 520 }
 521
 522 static void intr_complete (struct urb *urb)
 523 {
 524         struct usbnet   *dev = urb->context;
 525         int             status = urb->status;
 526
 527         switch (status) {
 528         /* success */
 529         case 0:
 530                 dev->driver_info->status(dev, urb);
 531                 break;
 532
 533         /* software-driven interface shutdown */
 534         case -ENOENT:           /* urb killed */
 535         case -ESHUTDOWN:        /* hardware gone */
 536                 netif_dbg(dev, ifdown, dev->net,
 537                           "intr shutdown, code %d\n", status);
 538                 return;
 539
 540         /* NOTE:  not throttling like RX/TX, since this endpoint
 541          * already polls infrequently
 542          */
 543         default:
 544                 netdev_dbg(dev->net, "intr status %d\n", status);
 545                 break;
 546         }
 547
 548         if (!netif_running (dev->net))
 549                 return;
 550
 551         memset(urb->transfer_buffer, 0, urb->transfer_buffer_length);
 552         status = usb_submit_urb (urb, GFP_ATOMIC);
 553         if (status != 0)
 554                 netif_err(dev, timer, dev->net,
 555                           "intr resubmit --> %d\n", status);
 556 }
 557
 558 /*-------------------------------------------------------------------------*/
 559 void usbnet_pause_rx(struct usbnet *dev)
 560 {
 561         set_bit(EVENT_RX_PAUSED, &dev->flags);
 562
 563         netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
 564 }
 565 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
 566
 567 void usbnet_resume_rx(struct usbnet *dev)
 568 {
 569         struct sk_buff *skb;
 570         int num = 0;
 571
 572         clear_bit(EVENT_RX_PAUSED, &dev->flags);
 573
 574         while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
 575                 usbnet_skb_return(dev, skb);
 576                 num++;
 577         }
 578
 579         tasklet_schedule(&dev->bh);
 580
 581         netif_dbg(dev, rx_status, dev->net,
 582                   "paused rx queue disabled, %d skbs requeued\n", num);
 583 }
 584 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
 585
 586 void usbnet_purge_paused_rxq(struct usbnet *dev)
 587 {
 588         skb_queue_purge(&dev->rxq_pause);
 589 }
 590 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
 591
 592 /*-------------------------------------------------------------------------*/
 593
 594 // unlink pending rx/tx; completion handlers do all other cleanup
 595
 596 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
 597 {
 598         unsigned long           flags;
 599         struct sk_buff          *skb;
 600         int                     count = 0;
 601
 602         spin_lock_irqsave (&q->lock, flags);
 603         while (!skb_queue_empty(q)) {
 604                 struct skb_data         *entry;
 605                 struct urb              *urb;
 606                 int                     retval;
 607
 608                 skb_queue_walk(q, skb) {
 609                         entry = (struct skb_data *) skb->cb;
 610                         if (entry->state != unlink_start)
 611                                 goto found;
 612                 }
 613                 break;
 614 found:
 615                 entry->state = unlink_start;
 616                 urb = entry->urb;
 617
 618                 /*
 619                  * Get reference count of the URB to avoid it to be
 620                  * freed during usb_unlink_urb, which may trigger
 621                  * use-after-free problem inside usb_unlink_urb since
 622                  * usb_unlink_urb is always racing with .complete
 623                  * handler(include defer_bh).
 624                  */
 625                 usb_get_urb(urb);
 626                 spin_unlock_irqrestore(&q->lock, flags);
 627                 // during some PM-driven resume scenarios,
 628                 // these (async) unlinks complete immediately
 629                 retval = usb_unlink_urb (urb);
 630                 if (retval != -EINPROGRESS && retval != 0)
 631                         netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
 632                 else
 633                         count++;
 634                 usb_put_urb(urb);
 635                 spin_lock_irqsave(&q->lock, flags);
 636         }
 637         spin_unlock_irqrestore (&q->lock, flags);
 638         return count;
 639 }
 640
 641 // Flush all pending rx urbs
 642 // minidrivers may need to do this when the MTU changes
 643
 644 void usbnet_unlink_rx_urbs(struct usbnet *dev)
 645 {
 646         if (netif_running(dev->net)) {
 647                 (void) unlink_urbs (dev, &dev->rxq);
 648                 tasklet_schedule(&dev->bh);
 649         }
 650 }
 651 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
 652
 653 /*-------------------------------------------------------------------------*/
 654
 655 // precondition: never called in_interrupt
 656 static void usbnet_terminate_urbs(struct usbnet *dev)
 657 {
 658         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
 659         DECLARE_WAITQUEUE(wait, current);
 660         int temp;
 661
 662         /* ensure there are no more active urbs */
 663         add_wait_queue(&unlink_wakeup, &wait);
 664         set_current_state(TASK_UNINTERRUPTIBLE);
 665         dev->wait = &unlink_wakeup;
 666         temp = unlink_urbs(dev, &dev->txq) +
 667                 unlink_urbs(dev, &dev->rxq);
 668
 669         /* maybe wait for deletions to finish. */
 670         while (!skb_queue_empty(&dev->rxq)
 671                 && !skb_queue_empty(&dev->txq)
 672                 && !skb_queue_empty(&dev->done)) {
 673                         schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
 674                         set_current_state(TASK_UNINTERRUPTIBLE);
 675                         netif_dbg(dev, ifdown, dev->net,
 676                                   "waited for %d urb completions\n", temp);
 677         }
 678         set_current_state(TASK_RUNNING);
 679         dev->wait = NULL;
 680         remove_wait_queue(&unlink_wakeup, &wait);
 681 }
 682
 683 int usbnet_stop (struct net_device *net)
 684 {
 685         struct usbnet           *dev = netdev_priv(net);
 686         struct driver_info      *info = dev->driver_info;
 687         int                     retval;
 688
 689         clear_bit(EVENT_DEV_OPEN, &dev->flags);
 690         netif_stop_queue (net);
 691
 692         netif_info(dev, ifdown, dev->net,
 693                    "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
 694                    net->stats.rx_packets, net->stats.tx_packets,
 695                    net->stats.rx_errors, net->stats.tx_errors);
 696
 697         /* allow minidriver to stop correctly (wireless devices to turn off
 698          * radio etc) */
 699         if (info->stop) {
 700                 retval = info->stop(dev);
 701                 if (retval < 0)
 702                         netif_info(dev, ifdown, dev->net,
 703                                    "stop fail (%d) usbnet usb-%s-%s, %s\n",
 704                                    retval,
 705                                    dev->udev->bus->bus_name, dev->udev->devpath,
 706                                    info->description);
 707         }
 708
 709         if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
 710                 usbnet_terminate_urbs(dev);
 711
 712         usb_kill_urb(dev->interrupt);
 713
 714         usbnet_purge_paused_rxq(dev);
 715
 716         /* deferred work (task, timer, softirq) must also stop.
 717          * can't flush_scheduled_work() until we drop rtnl (later),
 718          * else workers could deadlock; so make workers a NOP.
 719          */
 720         dev->flags = 0;
 721         del_timer_sync (&dev->delay);
 722         tasklet_kill (&dev->bh);
 723         if (info->manage_power)
 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                         goto done;
 800                 usb_autopm_put_interface(dev->intf);
 801         }
 802         return retval;
 803
 804 done:
 805         usb_autopm_put_interface(dev->intf);
 806 done_nopm:
 807         return retval;
 808 }
 809 EXPORT_SYMBOL_GPL(usbnet_open);
 810
 811 /*-------------------------------------------------------------------------*/
 812
 813 /* ethtool methods; minidrivers may need to add some more, but
 814  * they'll probably want to use this base set.
 815  */
 816
 817 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
 818 {
 819         struct usbnet *dev = netdev_priv(net);
 820
 821         if (!dev->mii.mdio_read)
 822                 return -EOPNOTSUPP;
 823
 824         return mii_ethtool_gset(&dev->mii, cmd);
 825 }
 826 EXPORT_SYMBOL_GPL(usbnet_get_settings);
 827
 828 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
 829 {
 830         struct usbnet *dev = netdev_priv(net);
 831         int retval;
 832
 833         if (!dev->mii.mdio_write)
 834                 return -EOPNOTSUPP;
 835
 836         retval = mii_ethtool_sset(&dev->mii, cmd);
 837
 838         /* link speed/duplex might have changed */
 839         if (dev->driver_info->link_reset)
 840                 dev->driver_info->link_reset(dev);
 841
 842         return retval;
 843
 844 }
 845 EXPORT_SYMBOL_GPL(usbnet_set_settings);
 846
 847 u32 usbnet_get_link (struct net_device *net)
 848 {
 849         struct usbnet *dev = netdev_priv(net);
 850
 851         /* If a check_connect is defined, return its result */
 852         if (dev->driver_info->check_connect)
 853                 return dev->driver_info->check_connect (dev) == 0;
 854
 855         /* if the device has mii operations, use those */
 856         if (dev->mii.mdio_read)
 857                 return mii_link_ok(&dev->mii);
 858
 859         /* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
 860         return ethtool_op_get_link(net);
 861 }
 862 EXPORT_SYMBOL_GPL(usbnet_get_link);
 863
 864 int usbnet_nway_reset(struct net_device *net)
 865 {
 866         struct usbnet *dev = netdev_priv(net);
 867
 868         if (!dev->mii.mdio_write)
 869                 return -EOPNOTSUPP;
 870
 871         return mii_nway_restart(&dev->mii);
 872 }
 873 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
 874
 875 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
 876 {
 877         struct usbnet *dev = netdev_priv(net);
 878
 879         strncpy (info->driver, dev->driver_name, sizeof info->driver);
 880         strncpy (info->version, DRIVER_VERSION, sizeof info->version);
 881         strncpy (info->fw_version, dev->driver_info->description,
 882                 sizeof info->fw_version);
 883         usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
 884 }
 885 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
 886
 887 u32 usbnet_get_msglevel (struct net_device *net)
 888 {
 889         struct usbnet *dev = netdev_priv(net);
 890
 891         return dev->msg_enable;
 892 }
 893 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
 894
 895 void usbnet_set_msglevel (struct net_device *net, u32 level)
 896 {
 897         struct usbnet *dev = netdev_priv(net);
 898
 899         dev->msg_enable = level;
 900 }
 901 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
 902
 903 /* drivers may override default ethtool_ops in their bind() routine */
 904 static const struct ethtool_ops usbnet_ethtool_ops = {
 905         .get_settings           = usbnet_get_settings,
 906         .set_settings           = usbnet_set_settings,
 907         .get_link               = usbnet_get_link,
 908         .nway_reset             = usbnet_nway_reset,
 909         .get_drvinfo            = usbnet_get_drvinfo,
 910         .get_msglevel           = usbnet_get_msglevel,
 911         .set_msglevel           = usbnet_set_msglevel,
 912 };
 913
 914 /*-------------------------------------------------------------------------*/
 915
 916 /* work that cannot be done in interrupt context uses keventd.
 917  *
 918  * NOTE:  with 2.5 we could do more of this using completion callbacks,
 919  * especially now that control transfers can be queued.
 920  */
 921 static void
 922 kevent (struct work_struct *work)
 923 {
 924         struct usbnet           *dev =
 925                 container_of(work, struct usbnet, kevent);
 926         int                     status;
 927
 928         /* usb_clear_halt() needs a thread context */
 929         if (test_bit (EVENT_TX_HALT, &dev->flags)) {
 930                 unlink_urbs (dev, &dev->txq);
 931                 status = usb_autopm_get_interface(dev->intf);
 932                 if (status < 0)
 933                         goto fail_pipe;
 934                 status = usb_clear_halt (dev->udev, dev->out);
 935                 usb_autopm_put_interface(dev->intf);
 936                 if (status < 0 &&
 937                     status != -EPIPE &&
 938                     status != -ESHUTDOWN) {
 939                         if (netif_msg_tx_err (dev))
 940 fail_pipe:
 941                                 netdev_err(dev->net, "can't clear tx halt, status %d\n",
 942                                            status);
 943                 } else {
 944                         clear_bit (EVENT_TX_HALT, &dev->flags);
 945                         if (status != -ESHUTDOWN)
 946                                 netif_wake_queue (dev->net);
 947                 }
 948         }
 949         if (test_bit (EVENT_RX_HALT, &dev->flags)) {
 950                 unlink_urbs (dev, &dev->rxq);
 951                 status = usb_autopm_get_interface(dev->intf);
 952                 if (status < 0)
 953                         goto fail_halt;
 954                 status = usb_clear_halt (dev->udev, dev->in);
 955                 usb_autopm_put_interface(dev->intf);
 956                 if (status < 0 &&
 957                     status != -EPIPE &&
 958                     status != -ESHUTDOWN) {
 959                         if (netif_msg_rx_err (dev))
 960 fail_halt:
 961                                 netdev_err(dev->net, "can't clear rx halt, status %d\n",
 962                                            status);
 963                 } else {
 964                         clear_bit (EVENT_RX_HALT, &dev->flags);
 965                         tasklet_schedule (&dev->bh);
 966                 }
 967         }
 968
 969         /* tasklet could resubmit itself forever if memory is tight */
 970         if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
 971                 struct urb      *urb = NULL;
 972                 int resched = 1;
 973
 974                 if (netif_running (dev->net))
 975                         urb = usb_alloc_urb (0, GFP_KERNEL);
 976                 else
 977                         clear_bit (EVENT_RX_MEMORY, &dev->flags);
 978                 if (urb != NULL) {
 979                         clear_bit (EVENT_RX_MEMORY, &dev->flags);
 980                         status = usb_autopm_get_interface(dev->intf);
 981                         if (status < 0) {
 982                                 usb_free_urb(urb);
 983                                 goto fail_lowmem;
 984                         }
 985                         if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
 986                                 resched = 0;
 987                         usb_autopm_put_interface(dev->intf);
 988 fail_lowmem:
 989                         if (resched)
 990                                 tasklet_schedule (&dev->bh);
 991                 }
 992         }
 993
 994         if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
 995                 struct driver_info      *info = dev->driver_info;
 996                 int                     retval = 0;
 997
 998                 clear_bit (EVENT_LINK_RESET, &dev->flags);
 999                 status = usb_autopm_get_interface(dev->intf);
1000                 if (status < 0)
1001                         goto skip_reset;
1002                 if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1003                         usb_autopm_put_interface(dev->intf);
1004 skip_reset:
1005                         netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1006                                     retval,
1007                                     dev->udev->bus->bus_name,
1008                                     dev->udev->devpath,
1009                                     info->description);
1010                 } else {
1011                         usb_autopm_put_interface(dev->intf);
1012                 }
1013         }
1014
1015         if (dev->flags)
1016                 netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1017 }
1018
1019 /*-------------------------------------------------------------------------*/
1020
1021 static void tx_complete (struct urb *urb)
1022 {
1023         struct sk_buff          *skb = (struct sk_buff *) urb->context;
1024         struct skb_data         *entry = (struct skb_data *) skb->cb;
1025         struct usbnet           *dev = entry->dev;
1026
1027         if (urb->status == 0) {
1028                 if (!(dev->driver_info->flags & FLAG_MULTI_PACKET))
1029                         dev->net->stats.tx_packets++;
1030                 dev->net->stats.tx_bytes += entry->length;
1031         } else {
1032                 dev->net->stats.tx_errors++;
1033
1034                 switch (urb->status) {
1035                 case -EPIPE:
1036                         usbnet_defer_kevent (dev, EVENT_TX_HALT);
1037                         break;
1038
1039                 /* software-driven interface shutdown */
1040                 case -ECONNRESET:               // async unlink
1041                 case -ESHUTDOWN:                // hardware gone
1042                         break;
1043
1044                 // like rx, tx gets controller i/o faults during khubd delays
1045                 // and so it uses the same throttling mechanism.
1046                 case -EPROTO:
1047                 case -ETIME:
1048                 case -EILSEQ:
1049                         usb_mark_last_busy(dev->udev);
1050                         if (!timer_pending (&dev->delay)) {
1051                                 mod_timer (&dev->delay,
1052                                         jiffies + THROTTLE_JIFFIES);
1053                                 netif_dbg(dev, link, dev->net,
1054                                           "tx throttle %d\n", urb->status);
1055                         }
1056                         netif_stop_queue (dev->net);
1057                         break;
1058                 default:
1059                         netif_dbg(dev, tx_err, dev->net,
1060                                   "tx err %d\n", entry->urb->status);
1061                         break;
1062                 }
1063         }
1064
1065         usb_autopm_put_interface_async(dev->intf);
1066         (void) defer_bh(dev, skb, &dev->txq, tx_done);
1067 }
1068
1069 /*-------------------------------------------------------------------------*/
1070
1071 void usbnet_tx_timeout (struct net_device *net)
1072 {
1073         struct usbnet           *dev = netdev_priv(net);
1074
1075         unlink_urbs (dev, &dev->txq);
1076         tasklet_schedule (&dev->bh);
1077
1078         // FIXME: device recovery -- reset?
1079 }
1080 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1081
1082 /*-------------------------------------------------------------------------*/
1083
1084 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1085                                      struct net_device *net)
1086 {
1087         struct usbnet           *dev = netdev_priv(net);
1088         int                     length;
1089         struct urb              *urb = NULL;
1090         struct skb_data         *entry;
1091         struct driver_info      *info = dev->driver_info;
1092         unsigned long           flags;
1093         int retval;
1094
1095         if (skb)
1096                 skb_tx_timestamp(skb);
1097
1098         // some devices want funky USB-level framing, for
1099         // win32 driver (usually) and/or hardware quirks
1100         if (info->tx_fixup) {
1101                 skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1102                 if (!skb) {
1103                         if (netif_msg_tx_err(dev)) {
1104                                 netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1105                                 goto drop;
1106                         } else {
1107                                 /* cdc_ncm collected packet; waits for more */
1108                                 goto not_drop;
1109                         }
1110                 }
1111         }
1112         length = skb->len;
1113
1114 #ifdef CONFIG_ARCH_TEGRA
1115         // check and do the proper 32 byte alignment for sk buff
1116         if ((int)skb->data & 0x0000001F) {
1117                 struct sk_buff *new_skb = skb_copy_expand(skb, 32, 0, GFP_ATOMIC);
1118                 if(unlikely(!(new_skb)))
1119                         return -1;
1120                 kfree_skb(skb);
1121                 skb = new_skb;
1122         }
1123 #endif
1124
1125         if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1126                 netif_dbg(dev, tx_err, dev->net, "no urb\n");
1127                 goto drop;
1128         }
1129
1130         entry = (struct skb_data *) skb->cb;
1131         entry->urb = urb;
1132         entry->dev = dev;
1133         entry->length = length;
1134
1135         usb_fill_bulk_urb (urb, dev->udev, dev->out,
1136                         skb->data, skb->len, tx_complete, skb);
1137
1138         /* don't assume the hardware handles USB_ZERO_PACKET
1139          * NOTE:  strictly conforming cdc-ether devices should expect
1140          * the ZLP here, but ignore the one-byte packet.
1141          * NOTE2: CDC NCM specification is different from CDC ECM when
1142          * handling ZLP/short packets, so cdc_ncm driver will make short
1143          * packet itself if needed.
1144          */
1145         if (length % dev->maxpacket == 0) {
1146                 if (!(info->flags & FLAG_SEND_ZLP)) {
1147                         if (!(info->flags & FLAG_MULTI_PACKET)) {
1148                                 urb->transfer_buffer_length++;
1149                                 if (skb_tailroom(skb)) {
1150                                         skb->data[skb->len] = 0;
1151                                         __skb_put(skb, 1);
1152                                 }
1153                         }
1154                 } else
1155                         urb->transfer_flags |= URB_ZERO_PACKET;
1156         }
1157
1158         spin_lock_irqsave(&dev->txq.lock, flags);
1159         retval = usb_autopm_get_interface_async(dev->intf);
1160         if (retval < 0) {
1161                 spin_unlock_irqrestore(&dev->txq.lock, flags);
1162                 goto drop;
1163         }
1164
1165 #ifdef CONFIG_PM
1166         /* if this triggers the device is still a sleep */
1167         if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1168                 /* transmission will be done in resume */
1169                 usb_anchor_urb(urb, &dev->deferred);
1170                 /* no use to process more packets */
1171                 netif_stop_queue(net);
1172                 spin_unlock_irqrestore(&dev->txq.lock, flags);
1173                 netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1174                 goto deferred;
1175         }
1176 #endif
1177
1178         switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1179         case -EPIPE:
1180                 netif_stop_queue (net);
1181                 usbnet_defer_kevent (dev, EVENT_TX_HALT);
1182                 usb_autopm_put_interface_async(dev->intf);
1183                 break;
1184         default:
1185                 usb_autopm_put_interface_async(dev->intf);
1186                 netif_dbg(dev, tx_err, dev->net,
1187                           "tx: submit urb err %d\n", retval);
1188                 break;
1189         case 0:
1190                 net->trans_start = jiffies;
1191                 __usbnet_queue_skb(&dev->txq, skb, tx_start);
1192                 if (dev->txq.qlen >= TX_QLEN (dev))
1193                         netif_stop_queue (net);
1194         }
1195         spin_unlock_irqrestore (&dev->txq.lock, flags);
1196
1197         if (retval) {
1198                 netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1199 drop:
1200                 dev->net->stats.tx_dropped++;
1201 not_drop:
1202                 if (skb)
1203                         dev_kfree_skb_any (skb);
1204                 usb_free_urb (urb);
1205         } else
1206                 netif_dbg(dev, tx_queued, dev->net,
1207                           "> tx, len %d, type 0x%x\n", length, skb->protocol);
1208 #ifdef CONFIG_PM
1209 deferred:
1210 #endif
1211         return NETDEV_TX_OK;
1212 }
1213 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1214
1215 /*-------------------------------------------------------------------------*/
1216
1217 // tasklet (work deferred from completions, in_irq) or timer
1218
1219 static void usbnet_bh (unsigned long param)
1220 {
1221         struct usbnet           *dev = (struct usbnet *) param;
1222         struct sk_buff          *skb;
1223         struct skb_data         *entry;
1224
1225         while ((skb = skb_dequeue (&dev->done))) {
1226                 entry = (struct skb_data *) skb->cb;
1227                 switch (entry->state) {
1228                 case rx_done:
1229                         entry->state = rx_cleanup;
1230                         rx_process (dev, skb);
1231                         continue;
1232                 case tx_done:
1233                 case rx_cleanup:
1234                         usb_free_urb (entry->urb);
1235                         dev_kfree_skb (skb);
1236                         continue;
1237                 default:
1238                         netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1239                 }
1240         }
1241
1242         // waiting for all pending urbs to complete?
1243         if (dev->wait) {
1244                 if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
1245                         wake_up (dev->wait);
1246                 }
1247
1248         // or are we maybe short a few urbs?
1249         } else if (netif_running (dev->net) &&
1250                    netif_device_present (dev->net) &&
1251                    !timer_pending (&dev->delay) &&
1252                    !test_bit (EVENT_RX_HALT, &dev->flags)) {
1253                 int     temp = dev->rxq.qlen;
1254                 int     qlen = RX_QLEN (dev);
1255
1256                 if (temp < qlen) {
1257                         struct urb      *urb;
1258                         int             i;
1259
1260                         // don't refill the queue all at once
1261                         for (i = 0; i < 10 && dev->rxq.qlen < qlen; i++) {
1262                                 urb = usb_alloc_urb (0, GFP_ATOMIC);
1263                                 if (urb != NULL) {
1264                                         if (rx_submit (dev, urb, GFP_ATOMIC) ==
1265                                             -ENOLINK)
1266                                                 return;
1267                                 }
1268                         }
1269                         if (temp != dev->rxq.qlen)
1270                                 netif_dbg(dev, link, dev->net,
1271                                           "rxqlen %d --> %d\n",
1272                                           temp, dev->rxq.qlen);
1273                         if (dev->rxq.qlen < qlen)
1274                                 tasklet_schedule (&dev->bh);
1275                 }
1276                 if (dev->txq.qlen < TX_QLEN (dev))
1277                         netif_wake_queue (dev->net);
1278         }
1279 }
1280
1281
1282 /*-------------------------------------------------------------------------
1283  *
1284  * USB Device Driver support
1285  *
1286  *-------------------------------------------------------------------------*/
1287
1288 // precondition: never called in_interrupt
1289
1290 void usbnet_disconnect (struct usb_interface *intf)
1291 {
1292         struct usbnet           *dev;
1293         struct usb_device       *xdev;
1294         struct net_device       *net;
1295
1296         dev = usb_get_intfdata(intf);
1297         usb_set_intfdata(intf, NULL);
1298         if (!dev)
1299                 return;
1300
1301         xdev = interface_to_usbdev (intf);
1302
1303         netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1304                    intf->dev.driver->name,
1305                    xdev->bus->bus_name, xdev->devpath,
1306                    dev->driver_info->description);
1307
1308         net = dev->net;
1309         unregister_netdev (net);
1310
1311         cancel_work_sync(&dev->kevent);
1312
1313         if (dev->driver_info->unbind)
1314                 dev->driver_info->unbind (dev, intf);
1315
1316         usb_kill_urb(dev->interrupt);
1317         usb_free_urb(dev->interrupt);
1318
1319         free_netdev(net);
1320         usb_put_dev (xdev);
1321 }
1322 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1323
1324 static const struct net_device_ops usbnet_netdev_ops = {
1325         .ndo_open               = usbnet_open,
1326         .ndo_stop               = usbnet_stop,
1327         .ndo_start_xmit         = usbnet_start_xmit,
1328         .ndo_tx_timeout         = usbnet_tx_timeout,
1329         .ndo_change_mtu         = usbnet_change_mtu,
1330         .ndo_set_mac_address    = eth_mac_addr,
1331         .ndo_validate_addr      = eth_validate_addr,
1332 };
1333
1334 /*-------------------------------------------------------------------------*/
1335
1336 // precondition: never called in_interrupt
1337
1338 static struct device_type wlan_type = {
1339         .name   = "wlan",
1340 };
1341
1342 static struct device_type wwan_type = {
1343         .name   = "wwan",
1344 };
1345
1346 int
1347 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1348 {
1349         struct usbnet                   *dev;
1350         struct net_device               *net;
1351         struct usb_host_interface       *interface;
1352         struct driver_info              *info;
1353         struct usb_device               *xdev;
1354         int                             status;
1355         const char                      *name;
1356         struct usb_driver       *driver = to_usb_driver(udev->dev.driver);
1357
1358         /* usbnet already took usb runtime pm, so have to enable the feature
1359          * for usb interface, otherwise usb_autopm_get_interface may return
1360          * failure if USB_SUSPEND(RUNTIME_PM) is enabled.
1361          */
1362         if (!driver->supports_autosuspend) {
1363                 driver->supports_autosuspend = 1;
1364                 pm_runtime_enable(&udev->dev);
1365         }
1366
1367         name = udev->dev.driver->name;
1368         info = (struct driver_info *) prod->driver_info;
1369         if (!info) {
1370                 dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1371                 return -ENODEV;
1372         }
1373         xdev = interface_to_usbdev (udev);
1374         interface = udev->cur_altsetting;
1375
1376         usb_get_dev (xdev);
1377
1378         status = -ENOMEM;
1379
1380         // set up our own records
1381         net = alloc_etherdev(sizeof(*dev));
1382         if (!net)
1383                 goto out;
1384
1385         /* netdev_printk() needs this so do it as early as possible */
1386         SET_NETDEV_DEV(net, &udev->dev);
1387
1388         dev = netdev_priv(net);
1389         dev->udev = xdev;
1390         dev->intf = udev;
1391         dev->driver_info = info;
1392         dev->driver_name = name;
1393         dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1394                                 | NETIF_MSG_PROBE | NETIF_MSG_LINK);
1395         skb_queue_head_init (&dev->rxq);
1396         skb_queue_head_init (&dev->txq);
1397         skb_queue_head_init (&dev->done);
1398         skb_queue_head_init(&dev->rxq_pause);
1399         dev->bh.func = usbnet_bh;
1400         dev->bh.data = (unsigned long) dev;
1401         INIT_WORK (&dev->kevent, kevent);
1402         init_usb_anchor(&dev->deferred);
1403         dev->delay.function = usbnet_bh;
1404         dev->delay.data = (unsigned long) dev;
1405         init_timer (&dev->delay);
1406         mutex_init (&dev->phy_mutex);
1407
1408         dev->net = net;
1409         strcpy (net->name, "usb%d");
1410         memcpy (net->dev_addr, node_id, sizeof node_id);
1411
1412         /* rx and tx sides can use different message sizes;
1413          * bind() should set rx_urb_size in that case.
1414          */
1415         dev->hard_mtu = net->mtu + net->hard_header_len;
1416 #if 0
1417 // dma_supported() is deeply broken on almost all architectures
1418         // possible with some EHCI controllers
1419         if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1420                 net->features |= NETIF_F_HIGHDMA;
1421 #endif
1422
1423         net->netdev_ops = &usbnet_netdev_ops;
1424         net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1425         net->ethtool_ops = &usbnet_ethtool_ops;
1426
1427         // allow device-specific bind/init procedures
1428         // NOTE net->name still not usable ...
1429         if (info->bind) {
1430                 status = info->bind (dev, udev);
1431                 if (status < 0)
1432                         goto out1;
1433
1434                 // heuristic:  "usb%d" for links we know are two-host,
1435                 // else "eth%d" when there's reasonable doubt.  userspace
1436                 // can rename the link if it knows better.
1437                 if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1438                     ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1439                      (net->dev_addr [0] & 0x02) == 0))
1440                         strcpy (net->name, "eth%d");
1441                 /* WLAN devices should always be named "wlan%d" */
1442                 if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1443                         strcpy(net->name, "wlan%d");
1444                 /* WWAN devices should always be named "wwan%d" */
1445                 if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1446                         strcpy(net->name, "wwan%d");
1447
1448                 /* maybe the remote can't receive an Ethernet MTU */
1449                 if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1450                         net->mtu = dev->hard_mtu - net->hard_header_len;
1451         } else if (!info->in || !info->out)
1452                 status = usbnet_get_endpoints (dev, udev);
1453         else {
1454                 dev->in = usb_rcvbulkpipe (xdev, info->in);
1455                 dev->out = usb_sndbulkpipe (xdev, info->out);
1456                 if (!(info->flags & FLAG_NO_SETINT))
1457                         status = usb_set_interface (xdev,
1458                                 interface->desc.bInterfaceNumber,
1459                                 interface->desc.bAlternateSetting);
1460                 else
1461                         status = 0;
1462
1463         }
1464         if (status >= 0 && dev->status)
1465                 status = init_status (dev, udev);
1466         if (status < 0)
1467                 goto out3;
1468
1469         if (!dev->rx_urb_size)
1470                 dev->rx_urb_size = dev->hard_mtu;
1471         dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1472
1473         if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1474                 SET_NETDEV_DEVTYPE(net, &wlan_type);
1475         if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1476                 SET_NETDEV_DEVTYPE(net, &wwan_type);
1477
1478         status = register_netdev (net);
1479         if (status)
1480                 goto out4;
1481         netif_info(dev, probe, dev->net,
1482                    "register '%s' at usb-%s-%s, %s, %pM\n",
1483                    udev->dev.driver->name,
1484                    xdev->bus->bus_name, xdev->devpath,
1485                    dev->driver_info->description,
1486                    net->dev_addr);
1487
1488         // ok, it's ready to go.
1489         usb_set_intfdata (udev, dev);
1490
1491         netif_device_attach (net);
1492
1493         if (dev->driver_info->flags & FLAG_LINK_INTR)
1494                 netif_carrier_off(net);
1495
1496         return 0;
1497
1498 out4:
1499         usb_free_urb(dev->interrupt);
1500 out3:
1501         if (info->unbind)
1502                 info->unbind (dev, udev);
1503 out1:
1504         free_netdev(net);
1505 out:
1506         usb_put_dev(xdev);
1507         return status;
1508 }
1509 EXPORT_SYMBOL_GPL(usbnet_probe);
1510
1511 /*-------------------------------------------------------------------------*/
1512
1513 /*
1514  * suspend the whole driver as soon as the first interface is suspended
1515  * resume only when the last interface is resumed
1516  */
1517
1518 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1519 {
1520         struct usbnet           *dev = usb_get_intfdata(intf);
1521
1522         if (!dev->suspend_count++) {
1523                 spin_lock_irq(&dev->txq.lock);
1524                 /* don't autosuspend while transmitting */
1525                 if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1526                         spin_unlock_irq(&dev->txq.lock);
1527                         return -EBUSY;
1528                 } else {
1529                         set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1530                         spin_unlock_irq(&dev->txq.lock);
1531                 }
1532                 /*
1533                  * accelerate emptying of the rx and queues, to avoid
1534                  * having everything error out.
1535                  */
1536                 netif_device_detach (dev->net);
1537                 usbnet_terminate_urbs(dev);
1538                 usb_kill_urb(dev->interrupt);
1539
1540                 /*
1541                  * reattach so runtime management can use and
1542                  * wake the device
1543                  */
1544                 netif_device_attach (dev->net);
1545         }
1546         return 0;
1547 }
1548 EXPORT_SYMBOL_GPL(usbnet_suspend);
1549
1550 int usbnet_resume (struct usb_interface *intf)
1551 {
1552         struct usbnet           *dev = usb_get_intfdata(intf);
1553         struct sk_buff          *skb;
1554         struct urb              *res;
1555         int                     retval;
1556
1557         if (!--dev->suspend_count) {
1558                 /* resume interrupt URBs */
1559                 if (dev->interrupt && test_bit(EVENT_DEV_OPEN, &dev->flags))
1560                         usb_submit_urb(dev->interrupt, GFP_NOIO);
1561
1562                 spin_lock_irq(&dev->txq.lock);
1563                 while ((res = usb_get_from_anchor(&dev->deferred))) {
1564
1565                         skb = (struct sk_buff *)res->context;
1566                         retval = usb_submit_urb(res, GFP_ATOMIC);
1567                         if (retval < 0) {
1568                                 dev_kfree_skb_any(skb);
1569                                 usb_free_urb(res);
1570                                 usb_autopm_put_interface_async(dev->intf);
1571                         } else {
1572                                 dev->net->trans_start = jiffies;
1573                                 __skb_queue_tail(&dev->txq, skb);
1574                         }
1575                 }
1576
1577                 smp_mb();
1578                 clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1579                 spin_unlock_irq(&dev->txq.lock);
1580
1581                 if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1582                         if (!(dev->txq.qlen >= TX_QLEN(dev)))
1583                                 netif_tx_wake_all_queues(dev->net);
1584                         tasklet_schedule (&dev->bh);
1585                 }
1586         }
1587         return 0;
1588 }
1589 EXPORT_SYMBOL_GPL(usbnet_resume);
1590
1591
1592 /*-------------------------------------------------------------------------*/
1593
1594 static int __init usbnet_init(void)
1595 {
1596         /* Compiler should optimize this out. */
1597         BUILD_BUG_ON(
1598                 FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
1599
1600         random_ether_addr(node_id);
1601         return 0;
1602 }
1603 module_init(usbnet_init);
1604
1605 static void __exit usbnet_exit(void)
1606 {
1607 }
1608 module_exit(usbnet_exit);
1609
1610 MODULE_AUTHOR("David Brownell");
1611 MODULE_DESCRIPTION("USB network driver framework");
1612 MODULE_LICENSE("GPL");