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 static char version[] =
  53 KERN_INFO "USBNET Framwork for ASIX USB Ethernet Adapter:3.2.101 Beta6"
  54         " " __TIME__ " " __DATE__ "\n";
  55
  56 /*-------------------------------------------------------------------------*/
  57
  58 /*
  59  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
  60  * Several dozen bytes of IPv4 data can fit in two such transactions.
  61  * One maximum size Ethernet packet takes twenty four of them.
  62  * For high speed, each frame comfortably fits almost 36 max size
  63  * Ethernet packets (so queues should be bigger).
  64  *
  65  * REVISIT qlens should be members of 'struct usbnet'; the goal is to
  66  * let the USB host controller be busy for 5msec or more before an irq
  67  * is required, under load.  Jumbograms change the equation.
  68  */
  69 #define RX_MAX_QUEUE_MEMORY (60 * 1518)
  70 #define RX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
  71                         (RX_MAX_QUEUE_MEMORY/(dev)->rx_urb_size) : 4)
  72 #define TX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
  73                         (RX_MAX_QUEUE_MEMORY/(dev)->hard_mtu) : 4)
  74
  75 // reawaken network queue this soon after stopping; else watchdog barks
  76 #define TX_TIMEOUT_JIFFIES      (5*HZ)
  77
  78 // throttle rx/tx briefly after some faults, so khubd might disconnect()
  79 // us (it polls at HZ/4 usually) before we report too many false errors.
  80 #define THROTTLE_JIFFIES        (HZ/8)
  81
  82 // between wakeups
  83 #define UNLINK_TIMEOUT_MS       3
  84
  85 /*-------------------------------------------------------------------------*/
  86
  87 // randomly generated ethernet address
  88 static u8       node_id [ETH_ALEN];
  89
  90 static const char driver_name [] = "usbnet";
  91
  92 /* use ethtool to change the level for any given device */
  93 static int msg_level = -1;
  94 module_param (msg_level, int, 0);
  95 MODULE_PARM_DESC (msg_level, "Override default message level");
  96
  97 /*-------------------------------------------------------------------------*/
  98
  99 /* handles CDC Ethernet and many other network "bulk data" interfaces */
 100 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
 101 {
 102         int                             tmp;
 103         struct usb_host_interface       *alt = NULL;
 104         struct usb_host_endpoint        *in = NULL, *out = NULL;
 105         struct usb_host_endpoint        *status = NULL;
 106
 107         for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
 108                 unsigned        ep;
 109
 110                 in = out = status = NULL;
 111                 alt = intf->altsetting + tmp;
 112
 113                 /* take the first altsetting with in-bulk + out-bulk;
 114                  * remember any status endpoint, just in case;
 115                  * ignore other endpoints and altsettings.
 116                  */
 117                 for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
 118                         struct usb_host_endpoint        *e;
 119                         int                             intr = 0;
 120
 121                         e = alt->endpoint + ep;
 122                         switch (e->desc.bmAttributes) {
 123                         case USB_ENDPOINT_XFER_INT:
 124                                 if (!usb_endpoint_dir_in(&e->desc))
 125                                         continue;
 126                                 intr = 1;
 127                                 /* FALLTHROUGH */
 128                         case USB_ENDPOINT_XFER_BULK:
 129                                 break;
 130                         default:
 131                                 continue;
 132                         }
 133                         if (usb_endpoint_dir_in(&e->desc)) {
 134                                 if (!intr && !in)
 135                                         in = e;
 136                                 else if (intr && !status)
 137                                         status = e;
 138                         } else {
 139                                 if (!out)
 140                                         out = e;
 141                         }
 142                 }
 143                 if (in && out)
 144                         break;
 145         }
 146         if (!alt || !in || !out)
 147                 return -EINVAL;
 148
 149         if (alt->desc.bAlternateSetting != 0 ||
 150             !(dev->driver_info->flags & FLAG_NO_SETINT)) {
 151                 tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
 152                                 alt->desc.bAlternateSetting);
 153                 if (tmp < 0)
 154                         return tmp;
 155         }
 156
 157         dev->in = usb_rcvbulkpipe (dev->udev,
 158                         in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
 159         dev->out = usb_sndbulkpipe (dev->udev,
 160                         out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
 161         dev->status = status;
 162         return 0;
 163 }
 164 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
 165
 166 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
 167 {
 168         int             tmp, i;
 169         unsigned char   buf [13];
 170
 171         tmp = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
 172         if (tmp != 12) {
 173                 dev_dbg(&dev->udev->dev,
 174                         "bad MAC string %d fetch, %d\n", iMACAddress, tmp);
 175                 if (tmp >= 0)
 176                         tmp = -EINVAL;
 177                 return tmp;
 178         }
 179         for (i = tmp = 0; i < 6; i++, tmp += 2)
 180                 dev->net->dev_addr [i] =
 181                         (hex_to_bin(buf[tmp]) << 4) + hex_to_bin(buf[tmp + 1]);
 182         return 0;
 183 }
 184 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
 185
 186 static void intr_complete (struct urb *urb);
 187
 188 static int init_status (struct usbnet *dev, struct usb_interface *intf)
 189 {
 190         char            *buf = NULL;
 191         unsigned        pipe = 0;
 192         unsigned        maxp;
 193         unsigned        period;
 194
 195         if (!dev->driver_info->status)
 196                 return 0;
 197
 198         pipe = usb_rcvintpipe (dev->udev,
 199                         dev->status->desc.bEndpointAddress
 200                                 & USB_ENDPOINT_NUMBER_MASK);
 201         maxp = usb_maxpacket (dev->udev, pipe, 0);
 202
 203         /* avoid 1 msec chatter:  min 8 msec poll rate */
 204         period = max ((int) dev->status->desc.bInterval,
 205                 (dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
 206
 207         buf = kmalloc (maxp, GFP_KERNEL);
 208         if (buf) {
 209                 dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
 210                 if (!dev->interrupt) {
 211                         kfree (buf);
 212                         return -ENOMEM;
 213                 } else {
 214                         usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
 215                                 buf, maxp, intr_complete, dev, period);
 216                         dev_dbg(&intf->dev,
 217                                 "status ep%din, %d bytes period %d\n",
 218                                 usb_pipeendpoint(pipe), maxp, period);
 219                 }
 220         }
 221         return 0;
 222 }
 223
 224 /* Passes this packet up the stack, updating its accounting.
 225  * Some link protocols batch packets, so their rx_fixup paths
 226  * can return clones as well as just modify the original skb.
 227  */
 228 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
 229 {
 230         int     status;
 231
 232         if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
 233                 skb_queue_tail(&dev->rxq_pause, skb);
 234                 return;
 235         }
 236
 237         skb->protocol = eth_type_trans (skb, dev->net);
 238         dev->net->stats.rx_packets++;
 239         dev->net->stats.rx_bytes += skb->len;
 240
 241         netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
 242                   skb->len + sizeof (struct ethhdr), skb->protocol);
 243         memset (skb->cb, 0, sizeof (struct skb_data));
 244         status = netif_rx (skb);
 245         if (status != NET_RX_SUCCESS)
 246                 netif_dbg(dev, rx_err, dev->net,
 247                           "netif_rx status %d\n", status);
 248 }
 249 EXPORT_SYMBOL_GPL(usbnet_skb_return);
 250
 251
 252 /*-------------------------------------------------------------------------
 253  *
 254  * Network Device Driver (peer link to "Host Device", from USB host)
 255  *
 256  *-------------------------------------------------------------------------*/
 257
 258 int usbnet_change_mtu (struct net_device *net, int new_mtu)
 259 {
 260         struct usbnet   *dev = netdev_priv(net);
 261         int             ll_mtu = new_mtu + net->hard_header_len;
 262         int             old_hard_mtu = dev->hard_mtu;
 263         int             old_rx_urb_size = dev->rx_urb_size;
 264
 265         if (new_mtu <= 0)
 266                 return -EINVAL;
 267         // no second zero-length packet read wanted after mtu-sized packets
 268         if ((ll_mtu % dev->maxpacket) == 0)
 269                 return -EDOM;
 270         net->mtu = new_mtu;
 271
 272         dev->hard_mtu = net->mtu + net->hard_header_len;
 273         if (dev->rx_urb_size == old_hard_mtu) {
 274                 dev->rx_urb_size = dev->hard_mtu;
 275                 if (dev->rx_urb_size > old_rx_urb_size)
 276                         usbnet_unlink_rx_urbs(dev);
 277         }
 278
 279         return 0;
 280 }
 281 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
 282
 283 /* The caller must hold list->lock */
 284 static void __usbnet_queue_skb(struct sk_buff_head *list,
 285                         struct sk_buff *newsk, enum skb_state state)
 286 {
 287         struct skb_data *entry = (struct skb_data *) newsk->cb;
 288
 289         __skb_queue_tail(list, newsk);
 290         entry->state = state;
 291 }
 292
 293 /*-------------------------------------------------------------------------*/
 294
 295 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
 296  * completion callbacks.  2.5 should have fixed those bugs...
 297  */
 298
 299 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
 300                 struct sk_buff_head *list, enum skb_state state)
 301 {
 302         unsigned long           flags;
 303         enum skb_state          old_state;
 304         struct skb_data *entry = (struct skb_data *) skb->cb;
 305
 306         spin_lock_irqsave(&list->lock, flags);
 307         old_state = entry->state;
 308         entry->state = state;
 309         __skb_unlink(skb, list);
 310         spin_unlock(&list->lock);
 311         spin_lock(&dev->done.lock);
 312         __skb_queue_tail(&dev->done, skb);
 313         if (dev->done.qlen == 1)
 314                 tasklet_schedule(&dev->bh);
 315         spin_unlock_irqrestore(&dev->done.lock, flags);
 316         return old_state;
 317 }
 318
 319 /* some work can't be done in tasklets, so we use keventd
 320  *
 321  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
 322  * but tasklet_schedule() doesn't.  hope the failure is rare.
 323  */
 324 void usbnet_defer_kevent (struct usbnet *dev, int work)
 325 {
 326         set_bit (work, &dev->flags);
 327         if (!schedule_work (&dev->kevent))
 328                 netdev_err(dev->net, "kevent %d may have been dropped\n", work);
 329         else
 330                 netdev_dbg(dev->net, "kevent %d scheduled\n", work);
 331 }
 332 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
 333
 334 /*-------------------------------------------------------------------------*/
 335
 336 static void rx_complete (struct urb *urb);
 337
 338 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
 339 {
 340         struct sk_buff          *skb;
 341         struct skb_data         *entry;
 342         int                     retval = 0;
 343         unsigned long           lockflags;
 344         size_t                  size = dev->rx_urb_size;
 345
 346         if ((skb = alloc_skb (size + NET_IP_ALIGN, flags)) == NULL) {
 347                 netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
 348                 usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
 349                 usb_free_urb (urb);
 350                 return -ENOMEM;
 351         }
 352         //skb_reserve (skb, NET_IP_ALIGN);  //ylz++
 353
 354         entry = (struct skb_data *) skb->cb;
 355         entry->urb = urb;
 356         entry->dev = dev;
 357         entry->length = 0;
 358
 359         usb_fill_bulk_urb (urb, dev->udev, dev->in,
 360                 skb->data, size, rx_complete, skb);
 361
 362         spin_lock_irqsave (&dev->rxq.lock, lockflags);
 363
 364         if (netif_running (dev->net) &&
 365             netif_device_present (dev->net) &&
 366             !test_bit (EVENT_RX_HALT, &dev->flags) &&
 367             !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
 368                 switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
 369                 case -EPIPE:
 370                         usbnet_defer_kevent (dev, EVENT_RX_HALT);
 371                         break;
 372                 case -ENOMEM:
 373                         usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
 374                         break;
 375                 case -ENODEV:
 376                         netif_dbg(dev, ifdown, dev->net, "device gone\n");
 377                         netif_device_detach (dev->net);
 378                         break;
 379                 case -EHOSTUNREACH:
 380                         retval = -ENOLINK;
 381                         break;
 382                 default:
 383                         netif_dbg(dev, rx_err, dev->net,
 384                                   "rx submit, %d\n", retval);
 385                         tasklet_schedule (&dev->bh);
 386                         break;
 387                 case 0:
 388                         __usbnet_queue_skb(&dev->rxq, skb, rx_start);
 389                 }
 390         } else {
 391                 netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
 392                 retval = -ENOLINK;
 393         }
 394         spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
 395         if (retval) {
 396                 dev_kfree_skb_any (skb);
 397                 usb_free_urb (urb);
 398         }
 399         return retval;
 400 }
 401
 402
 403 /*-------------------------------------------------------------------------*/
 404
 405 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
 406 {
 407         if (dev->driver_info->rx_fixup &&
 408             !dev->driver_info->rx_fixup (dev, skb)) {
 409                 /* With RX_ASSEMBLE, rx_fixup() must update counters */
 410                 if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
 411                         dev->net->stats.rx_errors++;
 412                 goto done;
 413         }
 414         // else network stack removes extra byte if we forced a short packet
 415
 416         if (skb->len) {
 417                 /* all data was already cloned from skb inside the driver */
 418                 if (dev->driver_info->flags & FLAG_MULTI_PACKET)
 419                         dev_kfree_skb_any(skb);
 420                 else
 421                         usbnet_skb_return(dev, skb);
 422                 return;
 423         }
 424
 425         netif_dbg(dev, rx_err, dev->net, "drop\n");
 426         dev->net->stats.rx_errors++;
 427 done:
 428         skb_queue_tail(&dev->done, skb);
 429 }
 430
 431 /*-------------------------------------------------------------------------*/
 432
 433 static void rx_complete (struct urb *urb)
 434 {
 435         struct sk_buff          *skb = (struct sk_buff *) urb->context;
 436         struct skb_data         *entry = (struct skb_data *) skb->cb;
 437         struct usbnet           *dev = entry->dev;
 438         int                     urb_status = urb->status;
 439         enum skb_state          state;
 440
 441         skb_put (skb, urb->actual_length);
 442         state = rx_done;
 443         entry->urb = NULL;
 444
 445         switch (urb_status) {
 446         /* success */
 447         case 0:
 448                 if (skb->len < dev->net->hard_header_len) {
 449                         state = rx_cleanup;
 450                         dev->net->stats.rx_errors++;
 451                         dev->net->stats.rx_length_errors++;
 452                         netif_dbg(dev, rx_err, dev->net,
 453                                   "rx length %d\n", skb->len);
 454                 }
 455                 break;
 456
 457         /* stalls need manual reset. this is rare ... except that
 458          * when going through USB 2.0 TTs, unplug appears this way.
 459          * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
 460          * storm, recovering as needed.
 461          */
 462         case -EPIPE:
 463                 dev->net->stats.rx_errors++;
 464                 usbnet_defer_kevent (dev, EVENT_RX_HALT);
 465                 // FALLTHROUGH
 466
 467         /* software-driven interface shutdown */
 468         case -ECONNRESET:               /* async unlink */
 469         case -ESHUTDOWN:                /* hardware gone */
 470                 netif_dbg(dev, ifdown, dev->net,
 471                           "rx shutdown, code %d\n", urb_status);
 472                 goto block;
 473
 474         /* we get controller i/o faults during khubd disconnect() delays.
 475          * throttle down resubmits, to avoid log floods; just temporarily,
 476          * so we still recover when the fault isn't a khubd delay.
 477          */
 478         case -EPROTO:
 479         case -ETIME:
 480         case -EILSEQ:
 481                 dev->net->stats.rx_errors++;
 482                 if (!timer_pending (&dev->delay)) {
 483                         mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
 484                         netif_dbg(dev, link, dev->net,
 485                                   "rx throttle %d\n", urb_status);
 486                 }
 487 block:
 488                 state = rx_cleanup;
 489                 entry->urb = urb;
 490                 urb = NULL;
 491                 break;
 492
 493         /* data overrun ... flush fifo? */
 494         case -EOVERFLOW:
 495                 dev->net->stats.rx_over_errors++;
 496                 // FALLTHROUGH
 497
 498         default:
 499                 state = rx_cleanup;
 500                 dev->net->stats.rx_errors++;
 501                 netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
 502                 break;
 503         }
 504
 505         state = defer_bh(dev, skb, &dev->rxq, state);
 506
 507         if (urb) {
 508                 if (netif_running (dev->net) &&
 509                     !test_bit (EVENT_RX_HALT, &dev->flags) &&
 510                     state != unlink_start) {
 511                         rx_submit (dev, urb, GFP_ATOMIC);
 512                         return;
 513                 }
 514                 usb_free_urb (urb);
 515         }
 516         netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
 517 }
 518
 519 static void intr_complete (struct urb *urb)
 520 {
 521         struct usbnet   *dev = urb->context;
 522         int             status = urb->status;
 523
 524         switch (status) {
 525         /* success */
 526         case 0:
 527                 dev->driver_info->status(dev, urb);
 528                 break;
 529
 530         /* software-driven interface shutdown */
 531         case -ENOENT:           /* urb killed */
 532         case -ESHUTDOWN:        /* hardware gone */
 533                 netif_dbg(dev, ifdown, dev->net,
 534                           "intr shutdown, code %d\n", status);
 535                 return;
 536
 537         /* NOTE:  not throttling like RX/TX, since this endpoint
 538          * already polls infrequently
 539          */
 540         default:
 541                 netdev_dbg(dev->net, "intr status %d\n", status);
 542                 break;
 543         }
 544
 545         if (!netif_running (dev->net))
 546                 return;
 547
 548         memset(urb->transfer_buffer, 0, urb->transfer_buffer_length);
 549         status = usb_submit_urb (urb, GFP_ATOMIC);
 550         if (status != 0)
 551                 netif_err(dev, timer, dev->net,
 552                           "intr resubmit --> %d\n", status);
 553 }
 554
 555 /*-------------------------------------------------------------------------*/
 556 void usbnet_pause_rx(struct usbnet *dev)
 557 {
 558         set_bit(EVENT_RX_PAUSED, &dev->flags);
 559
 560         netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
 561 }
 562 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
 563
 564 void usbnet_resume_rx(struct usbnet *dev)
 565 {
 566         struct sk_buff *skb;
 567         int num = 0;
 568
 569         clear_bit(EVENT_RX_PAUSED, &dev->flags);
 570
 571         while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
 572                 usbnet_skb_return(dev, skb);
 573                 num++;
 574         }
 575
 576         tasklet_schedule(&dev->bh);
 577
 578         netif_dbg(dev, rx_status, dev->net,
 579                   "paused rx queue disabled, %d skbs requeued\n", num);
 580 }
 581 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
 582
 583 void usbnet_purge_paused_rxq(struct usbnet *dev)
 584 {
 585         skb_queue_purge(&dev->rxq_pause);
 586 }
 587 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
 588
 589 /*-------------------------------------------------------------------------*/
 590
 591 // unlink pending rx/tx; completion handlers do all other cleanup
 592
 593 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
 594 {
 595         unsigned long           flags;
 596         struct sk_buff          *skb;
 597         int                     count = 0;
 598
 599         spin_lock_irqsave (&q->lock, flags);
 600         while (!skb_queue_empty(q)) {
 601                 struct skb_data         *entry;
 602                 struct urb              *urb;
 603                 int                     retval;
 604
 605                 skb_queue_walk(q, skb) {
 606                         entry = (struct skb_data *) skb->cb;
 607                         if (entry->state != unlink_start)
 608                                 goto found;
 609                 }
 610                 break;
 611 found:
 612                 entry->state = unlink_start;
 613                 urb = entry->urb;
 614
 615                 /*
 616                  * Get reference count of the URB to avoid it to be
 617                  * freed during usb_unlink_urb, which may trigger
 618                  * use-after-free problem inside usb_unlink_urb since
 619                  * usb_unlink_urb is always racing with .complete
 620                  * handler(include defer_bh).
 621                  */
 622                 usb_get_urb(urb);
 623                 spin_unlock_irqrestore(&q->lock, flags);
 624                 // during some PM-driven resume scenarios,
 625                 // these (async) unlinks complete immediately
 626                 retval = usb_unlink_urb (urb);
 627                 if (retval != -EINPROGRESS && retval != 0)
 628                         netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
 629                 else
 630                         count++;
 631                 usb_put_urb(urb);
 632                 spin_lock_irqsave(&q->lock, flags);
 633         }
 634         spin_unlock_irqrestore (&q->lock, flags);
 635         return count;
 636 }
 637
 638 // Flush all pending rx urbs
 639 // minidrivers may need to do this when the MTU changes
 640
 641 void usbnet_unlink_rx_urbs(struct usbnet *dev)
 642 {
 643         if (netif_running(dev->net)) {
 644                 (void) unlink_urbs (dev, &dev->rxq);
 645                 tasklet_schedule(&dev->bh);
 646         }
 647 }
 648 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
 649
 650 /*-------------------------------------------------------------------------*/
 651
 652 // precondition: never called in_interrupt
 653 static void usbnet_terminate_urbs(struct usbnet *dev)
 654 {
 655         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
 656         DECLARE_WAITQUEUE(wait, current);
 657         int temp;
 658
 659         /* ensure there are no more active urbs */
 660         add_wait_queue(&unlink_wakeup, &wait);
 661         set_current_state(TASK_UNINTERRUPTIBLE);
 662         dev->wait = &unlink_wakeup;
 663         temp = unlink_urbs(dev, &dev->txq) +
 664                 unlink_urbs(dev, &dev->rxq);
 665
 666         /* maybe wait for deletions to finish. */
 667         while (!skb_queue_empty(&dev->rxq)
 668                 && !skb_queue_empty(&dev->txq)
 669                 && !skb_queue_empty(&dev->done)) {
 670                         schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
 671                         set_current_state(TASK_UNINTERRUPTIBLE);
 672                         netif_dbg(dev, ifdown, dev->net,
 673                                   "waited for %d urb completions\n", temp);
 674         }
 675         set_current_state(TASK_RUNNING);
 676         dev->wait = NULL;
 677         remove_wait_queue(&unlink_wakeup, &wait);
 678 }
 679
 680 int usbnet_stop (struct net_device *net)
 681 {
 682         struct usbnet           *dev = netdev_priv(net);
 683         struct driver_info      *info = dev->driver_info;
 684         int                     retval;
 685
 686         clear_bit(EVENT_DEV_OPEN, &dev->flags);
 687         netif_stop_queue (net);
 688
 689         netif_info(dev, ifdown, dev->net,
 690                    "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
 691                    net->stats.rx_packets, net->stats.tx_packets,
 692                    net->stats.rx_errors, net->stats.tx_errors);
 693
 694         /* allow minidriver to stop correctly (wireless devices to turn off
 695          * radio etc) */
 696         if (info->stop) {
 697                 retval = info->stop(dev);
 698                 if (retval < 0)
 699                         netif_info(dev, ifdown, dev->net,
 700                                    "stop fail (%d) usbnet usb-%s-%s, %s\n",
 701                                    retval,
 702                                    dev->udev->bus->bus_name, dev->udev->devpath,
 703                                    info->description);
 704         }
 705
 706         if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
 707                 usbnet_terminate_urbs(dev);
 708
 709         usb_kill_urb(dev->interrupt);
 710
 711         usbnet_purge_paused_rxq(dev);
 712
 713         /* deferred work (task, timer, softirq) must also stop.
 714          * can't flush_scheduled_work() until we drop rtnl (later),
 715          * else workers could deadlock; so make workers a NOP.
 716          */
 717         dev->flags = 0;
 718         del_timer_sync (&dev->delay);
 719         tasklet_kill (&dev->bh);
 720         if (info->manage_power)
 721                 info->manage_power(dev, 0);
 722         else
 723                 usb_autopm_put_interface(dev->intf);
 724
 725         return 0;
 726 }
 727 EXPORT_SYMBOL_GPL(usbnet_stop);
 728
 729 /*-------------------------------------------------------------------------*/
 730
 731 // posts reads, and enables write queuing
 732
 733 // precondition: never called in_interrupt
 734
 735 int usbnet_open (struct net_device *net)
 736 {
 737         struct usbnet           *dev = netdev_priv(net);
 738         int                     retval;
 739         struct driver_info      *info = dev->driver_info;
 740
 741         if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
 742                 netif_info(dev, ifup, dev->net,
 743                            "resumption fail (%d) usbnet usb-%s-%s, %s\n",
 744                            retval,
 745                            dev->udev->bus->bus_name,
 746                            dev->udev->devpath,
 747                            info->description);
 748                 goto done_nopm;
 749         }
 750
 751         // put into "known safe" state
 752         if (info->reset && (retval = info->reset (dev)) < 0) {
 753                 netif_info(dev, ifup, dev->net,
 754                            "open reset fail (%d) usbnet usb-%s-%s, %s\n",
 755                            retval,
 756                            dev->udev->bus->bus_name,
 757                            dev->udev->devpath,
 758                            info->description);
 759                 goto done;
 760         }
 761
 762         // insist peer be connected
 763         if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
 764                 netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
 765                 goto done;
 766         }
 767
 768         /* start any status interrupt transfer */
 769         if (dev->interrupt) {
 770                 retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
 771                 if (retval < 0) {
 772                         netif_err(dev, ifup, dev->net,
 773                                   "intr submit %d\n", retval);
 774                         goto done;
 775                 }
 776         }
 777
 778         set_bit(EVENT_DEV_OPEN, &dev->flags);
 779         netif_start_queue (net);
 780         netif_info(dev, ifup, dev->net,
 781                    "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
 782                    (int)RX_QLEN(dev), (int)TX_QLEN(dev),
 783                    dev->net->mtu,
 784                    (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
 785                    (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
 786                    (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
 787                    (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
 788                    (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
 789                    "simple");
 790
 791         // delay posting reads until we're fully open
 792         tasklet_schedule (&dev->bh);
 793         if (info->manage_power) {
 794                 retval = info->manage_power(dev, 1);
 795                 if (retval < 0)
 796                         goto done;
 797                 usb_autopm_put_interface(dev->intf);
 798         }
 799         return retval;
 800
 801 done:
 802         usb_autopm_put_interface(dev->intf);
 803 done_nopm:
 804         return retval;
 805 }
 806 EXPORT_SYMBOL_GPL(usbnet_open);
 807
 808 /*-------------------------------------------------------------------------*/
 809
 810 /* ethtool methods; minidrivers may need to add some more, but
 811  * they'll probably want to use this base set.
 812  */
 813
 814 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
 815 {
 816         struct usbnet *dev = netdev_priv(net);
 817
 818         if (!dev->mii.mdio_read)
 819                 return -EOPNOTSUPP;
 820
 821         return mii_ethtool_gset(&dev->mii, cmd);
 822 }
 823 EXPORT_SYMBOL_GPL(usbnet_get_settings);
 824
 825 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
 826 {
 827         struct usbnet *dev = netdev_priv(net);
 828         int retval;
 829
 830         if (!dev->mii.mdio_write)
 831                 return -EOPNOTSUPP;
 832
 833         retval = mii_ethtool_sset(&dev->mii, cmd);
 834
 835         /* link speed/duplex might have changed */
 836         if (dev->driver_info->link_reset)
 837                 dev->driver_info->link_reset(dev);
 838
 839         return retval;
 840
 841 }
 842 EXPORT_SYMBOL_GPL(usbnet_set_settings);
 843
 844 u32 usbnet_get_link (struct net_device *net)
 845 {
 846         struct usbnet *dev = netdev_priv(net);
 847
 848         /* If a check_connect is defined, return its result */
 849         if (dev->driver_info->check_connect)
 850                 return dev->driver_info->check_connect (dev) == 0;
 851
 852         /* if the device has mii operations, use those */
 853         if (dev->mii.mdio_read)
 854                 return mii_link_ok(&dev->mii);
 855
 856         /* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
 857         return ethtool_op_get_link(net);
 858 }
 859 EXPORT_SYMBOL_GPL(usbnet_get_link);
 860
 861 int usbnet_nway_reset(struct net_device *net)
 862 {
 863         struct usbnet *dev = netdev_priv(net);
 864
 865         if (!dev->mii.mdio_write)
 866                 return -EOPNOTSUPP;
 867
 868         return mii_nway_restart(&dev->mii);
 869 }
 870 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
 871
 872 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
 873 {
 874         struct usbnet *dev = netdev_priv(net);
 875
 876         strncpy (info->driver, dev->driver_name, sizeof info->driver);
 877         strncpy (info->version, DRIVER_VERSION, sizeof info->version);
 878         strncpy (info->fw_version, dev->driver_info->description,
 879                 sizeof info->fw_version);
 880         usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
 881 }
 882 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
 883
 884 u32 usbnet_get_msglevel (struct net_device *net)
 885 {
 886         struct usbnet *dev = netdev_priv(net);
 887
 888         return dev->msg_enable;
 889 }
 890 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
 891
 892 void usbnet_set_msglevel (struct net_device *net, u32 level)
 893 {
 894         struct usbnet *dev = netdev_priv(net);
 895
 896         dev->msg_enable = level;
 897 }
 898 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
 899
 900 /* drivers may override default ethtool_ops in their bind() routine */
 901 static const struct ethtool_ops usbnet_ethtool_ops = {
 902         .get_settings           = usbnet_get_settings,
 903         .set_settings           = usbnet_set_settings,
 904         .get_link               = usbnet_get_link,
 905         .nway_reset             = usbnet_nway_reset,
 906         .get_drvinfo            = usbnet_get_drvinfo,
 907         .get_msglevel           = usbnet_get_msglevel,
 908         .set_msglevel           = usbnet_set_msglevel,
 909 };
 910
 911 /*-------------------------------------------------------------------------*/
 912
 913 /* work that cannot be done in interrupt context uses keventd.
 914  *
 915  * NOTE:  with 2.5 we could do more of this using completion callbacks,
 916  * especially now that control transfers can be queued.
 917  */
 918 static void
 919 kevent (struct work_struct *work)
 920 {
 921         struct usbnet           *dev =
 922                 container_of(work, struct usbnet, kevent);
 923         int                     status;
 924
 925         /* usb_clear_halt() needs a thread context */
 926         if (test_bit (EVENT_TX_HALT, &dev->flags)) {
 927                 unlink_urbs (dev, &dev->txq);
 928                 status = usb_autopm_get_interface(dev->intf);
 929                 if (status < 0)
 930                         goto fail_pipe;
 931                 status = usb_clear_halt (dev->udev, dev->out);
 932                 usb_autopm_put_interface(dev->intf);
 933                 if (status < 0 &&
 934                     status != -EPIPE &&
 935                     status != -ESHUTDOWN) {
 936                         if (netif_msg_tx_err (dev))
 937 fail_pipe:
 938                                 netdev_err(dev->net, "can't clear tx halt, status %d\n",
 939                                            status);
 940                 } else {
 941                         clear_bit (EVENT_TX_HALT, &dev->flags);
 942                         if (status != -ESHUTDOWN)
 943                                 netif_wake_queue (dev->net);
 944                 }
 945         }
 946         if (test_bit (EVENT_RX_HALT, &dev->flags)) {
 947                 unlink_urbs (dev, &dev->rxq);
 948                 status = usb_autopm_get_interface(dev->intf);
 949                 if (status < 0)
 950                         goto fail_halt;
 951                 status = usb_clear_halt (dev->udev, dev->in);
 952                 usb_autopm_put_interface(dev->intf);
 953                 if (status < 0 &&
 954                     status != -EPIPE &&
 955                     status != -ESHUTDOWN) {
 956                         if (netif_msg_rx_err (dev))
 957 fail_halt:
 958                                 netdev_err(dev->net, "can't clear rx halt, status %d\n",
 959                                            status);
 960                 } else {
 961                         clear_bit (EVENT_RX_HALT, &dev->flags);
 962                         tasklet_schedule (&dev->bh);
 963                 }
 964         }
 965
 966         /* tasklet could resubmit itself forever if memory is tight */
 967         if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
 968                 struct urb      *urb = NULL;
 969                 int resched = 1;
 970
 971                 if (netif_running (dev->net))
 972                         urb = usb_alloc_urb (0, GFP_KERNEL);
 973                 else
 974                         clear_bit (EVENT_RX_MEMORY, &dev->flags);
 975                 if (urb != NULL) {
 976                         clear_bit (EVENT_RX_MEMORY, &dev->flags);
 977                         status = usb_autopm_get_interface(dev->intf);
 978                         if (status < 0) {
 979                                 usb_free_urb(urb);
 980                                 goto fail_lowmem;
 981                         }
 982                         if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
 983                                 resched = 0;
 984                         usb_autopm_put_interface(dev->intf);
 985 fail_lowmem:
 986                         if (resched)
 987                                 tasklet_schedule (&dev->bh);
 988                 }
 989         }
 990
 991         if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
 992                 struct driver_info      *info = dev->driver_info;
 993                 int                     retval = 0;
 994
 995                 clear_bit (EVENT_LINK_RESET, &dev->flags);
 996                 status = usb_autopm_get_interface(dev->intf);
 997                 if (status < 0)
 998                         goto skip_reset;
 999                 if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1000                         usb_autopm_put_interface(dev->intf);
1001 skip_reset:
1002                         netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1003                                     retval,
1004                                     dev->udev->bus->bus_name,
1005                                     dev->udev->devpath,
1006                                     info->description);
1007                 } else {
1008                         usb_autopm_put_interface(dev->intf);
1009                 }
1010         }
1011
1012         if (dev->flags)
1013                 netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1014 }
1015
1016 /*-------------------------------------------------------------------------*/
1017
1018 static void tx_complete (struct urb *urb)
1019 {
1020         struct sk_buff          *skb = (struct sk_buff *) urb->context;
1021         struct skb_data         *entry = (struct skb_data *) skb->cb;
1022         struct usbnet           *dev = entry->dev;
1023
1024         if (urb->status == 0) {
1025                 if (!(dev->driver_info->flags & FLAG_MULTI_PACKET))
1026                         dev->net->stats.tx_packets++;
1027                 dev->net->stats.tx_bytes += entry->length;
1028         } else {
1029                 dev->net->stats.tx_errors++;
1030
1031                 switch (urb->status) {
1032                 case -EPIPE:
1033                         usbnet_defer_kevent (dev, EVENT_TX_HALT);
1034                         break;
1035
1036                 /* software-driven interface shutdown */
1037                 case -ECONNRESET:               // async unlink
1038                 case -ESHUTDOWN:                // hardware gone
1039                         break;
1040
1041                 // like rx, tx gets controller i/o faults during khubd delays
1042                 // and so it uses the same throttling mechanism.
1043                 case -EPROTO:
1044                 case -ETIME:
1045                 case -EILSEQ:
1046                         usb_mark_last_busy(dev->udev);
1047                         if (!timer_pending (&dev->delay)) {
1048                                 mod_timer (&dev->delay,
1049                                         jiffies + THROTTLE_JIFFIES);
1050                                 netif_dbg(dev, link, dev->net,
1051                                           "tx throttle %d\n", urb->status);
1052                         }
1053                         netif_stop_queue (dev->net);
1054                         break;
1055                 default:
1056                         netif_dbg(dev, tx_err, dev->net,
1057                                   "tx err %d\n", entry->urb->status);
1058                         break;
1059                 }
1060         }
1061
1062         usb_autopm_put_interface_async(dev->intf);
1063         (void) defer_bh(dev, skb, &dev->txq, tx_done);
1064 }
1065
1066 /*-------------------------------------------------------------------------*/
1067
1068 void usbnet_tx_timeout (struct net_device *net)
1069 {
1070         struct usbnet           *dev = netdev_priv(net);
1071
1072         unlink_urbs (dev, &dev->txq);
1073         tasklet_schedule (&dev->bh);
1074
1075         // FIXME: device recovery -- reset?
1076 }
1077 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1078
1079 /*-------------------------------------------------------------------------*/
1080
1081 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1082                                      struct net_device *net)
1083 {
1084         struct usbnet           *dev = netdev_priv(net);
1085         int                     length;
1086         struct urb              *urb = NULL;
1087         struct skb_data         *entry;
1088         struct driver_info      *info = dev->driver_info;
1089         unsigned long           flags;
1090         int retval;
1091
1092         // some devices want funky USB-level framing, for
1093         // win32 driver (usually) and/or hardware quirks
1094         if (info->tx_fixup) {
1095                 skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1096                 if (!skb) {
1097                         if (netif_msg_tx_err(dev)) {
1098                                 netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1099                                 goto drop;
1100                         } else {
1101                                 /* cdc_ncm collected packet; waits for more */
1102                                 goto not_drop;
1103                         }
1104                 }
1105         }
1106         length = skb->len;
1107
1108         if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1109                 netif_dbg(dev, tx_err, dev->net, "no urb\n");
1110                 goto drop;
1111         }
1112
1113         entry = (struct skb_data *) skb->cb;
1114         entry->urb = urb;
1115         entry->dev = dev;
1116         entry->length = length;
1117
1118         usb_fill_bulk_urb (urb, dev->udev, dev->out,
1119                         skb->data, skb->len, tx_complete, skb);
1120
1121         /* don't assume the hardware handles USB_ZERO_PACKET
1122          * NOTE:  strictly conforming cdc-ether devices should expect
1123          * the ZLP here, but ignore the one-byte packet.
1124          * NOTE2: CDC NCM specification is different from CDC ECM when
1125          * handling ZLP/short packets, so cdc_ncm driver will make short
1126          * packet itself if needed.
1127          */
1128         if (length % dev->maxpacket == 0) {
1129                 if (!(info->flags & FLAG_SEND_ZLP)) {
1130                         if (!(info->flags & FLAG_MULTI_PACKET)) {
1131                                 urb->transfer_buffer_length++;
1132                                 if (skb_tailroom(skb)) {
1133                                         skb->data[skb->len] = 0;
1134                                         __skb_put(skb, 1);
1135                                 }
1136                         }
1137                 } else
1138                         urb->transfer_flags |= URB_ZERO_PACKET;
1139         }
1140
1141         spin_lock_irqsave(&dev->txq.lock, flags);
1142         retval = usb_autopm_get_interface_async(dev->intf);
1143         if (retval < 0) {
1144                 spin_unlock_irqrestore(&dev->txq.lock, flags);
1145                 goto drop;
1146         }
1147
1148 #ifdef CONFIG_PM
1149         /* if this triggers the device is still a sleep */
1150         if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1151                 /* transmission will be done in resume */
1152                 usb_anchor_urb(urb, &dev->deferred);
1153                 /* no use to process more packets */
1154                 netif_stop_queue(net);
1155                 spin_unlock_irqrestore(&dev->txq.lock, flags);
1156                 netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1157                 goto deferred;
1158         }
1159 #endif
1160
1161         switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1162         case -EPIPE:
1163                 netif_stop_queue (net);
1164                 usbnet_defer_kevent (dev, EVENT_TX_HALT);
1165                 usb_autopm_put_interface_async(dev->intf);
1166                 break;
1167         default:
1168                 usb_autopm_put_interface_async(dev->intf);
1169                 netif_dbg(dev, tx_err, dev->net,
1170                           "tx: submit urb err %d\n", retval);
1171                 break;
1172         case 0:
1173                 net->trans_start = jiffies;
1174                 __usbnet_queue_skb(&dev->txq, skb, tx_start);
1175                 if (dev->txq.qlen >= TX_QLEN (dev))
1176                         netif_stop_queue (net);
1177         }
1178         spin_unlock_irqrestore (&dev->txq.lock, flags);
1179
1180         if (retval) {
1181                 netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1182 drop:
1183                 dev->net->stats.tx_dropped++;
1184 not_drop:
1185                 if (skb)
1186                         dev_kfree_skb_any (skb);
1187                 usb_free_urb (urb);
1188         } else
1189                 netif_dbg(dev, tx_queued, dev->net,
1190                           "> tx, len %d, type 0x%x\n", length, skb->protocol);
1191 #ifdef CONFIG_PM
1192 deferred:
1193 #endif
1194         return NETDEV_TX_OK;
1195 }
1196 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1197
1198 /*-------------------------------------------------------------------------*/
1199
1200 // tasklet (work deferred from completions, in_irq) or timer
1201
1202 static void usbnet_bh (unsigned long param)
1203 {
1204         struct usbnet           *dev = (struct usbnet *) param;
1205         struct sk_buff          *skb;
1206         struct skb_data         *entry;
1207
1208         while ((skb = skb_dequeue (&dev->done))) {
1209                 entry = (struct skb_data *) skb->cb;
1210                 switch (entry->state) {
1211                 case rx_done:
1212                         entry->state = rx_cleanup;
1213                         rx_process (dev, skb);
1214                         continue;
1215                 case tx_done:
1216                 case rx_cleanup:
1217                         usb_free_urb (entry->urb);
1218                         dev_kfree_skb (skb);
1219                         continue;
1220                 default:
1221                         netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1222                 }
1223         }
1224
1225         // waiting for all pending urbs to complete?
1226         if (dev->wait) {
1227                 if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
1228                         wake_up (dev->wait);
1229                 }
1230
1231         // or are we maybe short a few urbs?
1232         } else if (netif_running (dev->net) &&
1233                    netif_device_present (dev->net) &&
1234                    !timer_pending (&dev->delay) &&
1235                    !test_bit (EVENT_RX_HALT, &dev->flags)) {
1236                 int     temp = dev->rxq.qlen;
1237                 int     qlen = RX_QLEN (dev);
1238
1239                 if (temp < qlen) {
1240                         struct urb      *urb;
1241                         int             i;
1242
1243                         // don't refill the queue all at once
1244                         for (i = 0; i < 10 && dev->rxq.qlen < qlen; i++) {
1245                                 urb = usb_alloc_urb (0, GFP_ATOMIC);
1246                                 if (urb != NULL) {
1247                                         if (rx_submit (dev, urb, GFP_ATOMIC) ==
1248                                             -ENOLINK)
1249                                                 return;
1250                                 }
1251                         }
1252                         if (temp != dev->rxq.qlen)
1253                                 netif_dbg(dev, link, dev->net,
1254                                           "rxqlen %d --> %d\n",
1255                                           temp, dev->rxq.qlen);
1256                         if (dev->rxq.qlen < qlen)
1257                                 tasklet_schedule (&dev->bh);
1258                 }
1259                 if (dev->txq.qlen < TX_QLEN (dev))
1260                         netif_wake_queue (dev->net);
1261         }
1262 }
1263
1264
1265 /*-------------------------------------------------------------------------
1266  *
1267  * USB Device Driver support
1268  *
1269  *-------------------------------------------------------------------------*/
1270
1271 // precondition: never called in_interrupt
1272
1273 void usbnet_disconnect (struct usb_interface *intf)
1274 {
1275         struct usbnet           *dev;
1276         struct usb_device       *xdev;
1277         struct net_device       *net;
1278
1279         dev = usb_get_intfdata(intf);
1280         usb_set_intfdata(intf, NULL);
1281         if (!dev)
1282                 return;
1283
1284         xdev = interface_to_usbdev (intf);
1285
1286         netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1287                    intf->dev.driver->name,
1288                    xdev->bus->bus_name, xdev->devpath,
1289                    dev->driver_info->description);
1290
1291         net = dev->net;
1292         unregister_netdev (net);
1293
1294         cancel_work_sync(&dev->kevent);
1295
1296         if (dev->driver_info->unbind)
1297                 dev->driver_info->unbind (dev, intf);
1298
1299         usb_kill_urb(dev->interrupt);
1300         usb_free_urb(dev->interrupt);
1301
1302         free_netdev(net);
1303         usb_put_dev (xdev);
1304 }
1305 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1306
1307 static const struct net_device_ops usbnet_netdev_ops = {
1308         .ndo_open               = usbnet_open,
1309         .ndo_stop               = usbnet_stop,
1310         .ndo_start_xmit         = usbnet_start_xmit,
1311         .ndo_tx_timeout         = usbnet_tx_timeout,
1312         .ndo_change_mtu         = usbnet_change_mtu,
1313         .ndo_set_mac_address    = eth_mac_addr,
1314         .ndo_validate_addr      = eth_validate_addr,
1315 };
1316
1317 /*-------------------------------------------------------------------------*/
1318
1319 // precondition: never called in_interrupt
1320
1321 static struct device_type wlan_type = {
1322         .name   = "wlan",
1323 };
1324
1325 static struct device_type wwan_type = {
1326         .name   = "wwan",
1327 };
1328
1329 int
1330 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1331 {
1332         struct usbnet                   *dev;
1333         struct net_device               *net;
1334         struct usb_host_interface       *interface;
1335         struct driver_info              *info;
1336         struct usb_device               *xdev;
1337         int                             status;
1338         const char                      *name;
1339         struct usb_driver       *driver = to_usb_driver(udev->dev.driver);
1340
1341         /* usbnet already took usb runtime pm, so have to enable the feature
1342          * for usb interface, otherwise usb_autopm_get_interface may return
1343          * failure if USB_SUSPEND(RUNTIME_PM) is enabled.
1344          */
1345         if (!driver->supports_autosuspend) {
1346                 driver->supports_autosuspend = 1;
1347                 pm_runtime_enable(&udev->dev);
1348         }
1349
1350         name = udev->dev.driver->name;
1351         info = (struct driver_info *) prod->driver_info;
1352         if (!info) {
1353                 dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1354                 return -ENODEV;
1355         }
1356         xdev = interface_to_usbdev (udev);
1357         interface = udev->cur_altsetting;
1358
1359         usb_get_dev (xdev);
1360
1361         status = -ENOMEM;
1362
1363         // set up our own records
1364         net = alloc_etherdev(sizeof(*dev));
1365         if (!net) {
1366                 dbg ("can't kmalloc dev");
1367                 goto out;
1368         }
1369
1370         /* netdev_printk() needs this so do it as early as possible */
1371         SET_NETDEV_DEV(net, &udev->dev);
1372
1373         dev = netdev_priv(net);
1374         dev->udev = xdev;
1375         dev->intf = udev;
1376         dev->driver_info = info;
1377         dev->driver_name = name;
1378         dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1379                                 | NETIF_MSG_PROBE | NETIF_MSG_LINK);
1380         skb_queue_head_init (&dev->rxq);
1381         skb_queue_head_init (&dev->txq);
1382         skb_queue_head_init (&dev->done);
1383         skb_queue_head_init(&dev->rxq_pause);
1384         dev->bh.func = usbnet_bh;
1385         dev->bh.data = (unsigned long) dev;
1386         INIT_WORK (&dev->kevent, kevent);
1387         init_usb_anchor(&dev->deferred);
1388         dev->delay.function = usbnet_bh;
1389         dev->delay.data = (unsigned long) dev;
1390         init_timer (&dev->delay);
1391         mutex_init (&dev->phy_mutex);
1392
1393         dev->net = net;
1394         strcpy (net->name, "usb%d");
1395         memcpy (net->dev_addr, node_id, sizeof node_id);
1396
1397         /* rx and tx sides can use different message sizes;
1398          * bind() should set rx_urb_size in that case.
1399          */
1400         dev->hard_mtu = net->mtu + net->hard_header_len;
1401 #if 0
1402 // dma_supported() is deeply broken on almost all architectures
1403         // possible with some EHCI controllers
1404         if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1405                 net->features |= NETIF_F_HIGHDMA;
1406 #endif
1407
1408         net->netdev_ops = &usbnet_netdev_ops;
1409         net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1410         net->ethtool_ops = &usbnet_ethtool_ops;
1411
1412         info->flags |= FLAG_AVOID_UNLINK_URBS;
1413
1414         // allow device-specific bind/init procedures
1415         // NOTE net->name still not usable ...
1416         if (info->bind) {
1417                 status = info->bind (dev, udev);
1418                 if (status < 0)
1419                         goto out1;
1420
1421                 // heuristic:  "usb%d" for links we know are two-host,
1422                 // else "eth%d" when there's reasonable doubt.  userspace
1423                 // can rename the link if it knows better.
1424                 if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1425                     ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1426                      (net->dev_addr [0] & 0x02) == 0))
1427                         strcpy (net->name, "eth%d");
1428                 /* WLAN devices should always be named "wlan%d" */
1429                 if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1430                         strcpy(net->name, "wlan%d");
1431                 /* WWAN devices should always be named "wwan%d" */
1432                 if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1433                         strcpy(net->name, "wwan%d");
1434
1435                 /* maybe the remote can't receive an Ethernet MTU */
1436                 if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1437                         net->mtu = dev->hard_mtu - net->hard_header_len;
1438         } else if (!info->in || !info->out)
1439                 status = usbnet_get_endpoints (dev, udev);
1440         else {
1441                 dev->in = usb_rcvbulkpipe (xdev, info->in);
1442                 dev->out = usb_sndbulkpipe (xdev, info->out);
1443                 if (!(info->flags & FLAG_NO_SETINT))
1444                         status = usb_set_interface (xdev,
1445                                 interface->desc.bInterfaceNumber,
1446                                 interface->desc.bAlternateSetting);
1447                 else
1448                         status = 0;
1449
1450         }
1451         if (status >= 0 && dev->status)
1452                 status = init_status (dev, udev);
1453         if (status < 0)
1454                 goto out3;
1455
1456         if (!dev->rx_urb_size)
1457                 dev->rx_urb_size = dev->hard_mtu;
1458         dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1459
1460         if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1461                 SET_NETDEV_DEVTYPE(net, &wlan_type);
1462         if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1463                 SET_NETDEV_DEVTYPE(net, &wwan_type);
1464
1465         status = register_netdev (net);
1466         if (status)
1467                 goto out3;
1468         netif_info(dev, probe, dev->net,
1469                    "register '%s' at usb-%s-%s, %s, %pM\n",
1470                    udev->dev.driver->name,
1471                    xdev->bus->bus_name, xdev->devpath,
1472                    dev->driver_info->description,
1473                    net->dev_addr);
1474
1475         // ok, it's ready to go.
1476         usb_set_intfdata (udev, dev);
1477
1478         netif_device_attach (net);
1479
1480         if (dev->driver_info->flags & FLAG_LINK_INTR)
1481                 netif_carrier_off(net);
1482
1483         return 0;
1484
1485 out3:
1486         if (info->unbind)
1487                 info->unbind (dev, udev);
1488 out1:
1489         free_netdev(net);
1490 out:
1491         usb_put_dev(xdev);
1492         return status;
1493 }
1494 EXPORT_SYMBOL_GPL(usbnet_probe);
1495
1496 /*-------------------------------------------------------------------------*/
1497
1498 /*
1499  * suspend the whole driver as soon as the first interface is suspended
1500  * resume only when the last interface is resumed
1501  */
1502
1503 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1504 {
1505         struct usbnet           *dev = usb_get_intfdata(intf);
1506
1507         if (!dev->suspend_count++) {
1508                 spin_lock_irq(&dev->txq.lock);
1509                 /* don't autosuspend while transmitting */
1510                 if (dev->txq.qlen && (message.event & PM_EVENT_AUTO)) {
1511                         spin_unlock_irq(&dev->txq.lock);
1512                         return -EBUSY;
1513                 } else {
1514                         set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1515                         spin_unlock_irq(&dev->txq.lock);
1516                 }
1517                 /*
1518                  * accelerate emptying of the rx and queues, to avoid
1519                  * having everything error out.
1520                  */
1521                 netif_device_detach (dev->net);
1522                 usbnet_terminate_urbs(dev);
1523                 usb_kill_urb(dev->interrupt);
1524
1525                 /*
1526                  * reattach so runtime management can use and
1527                  * wake the device
1528                  */
1529                 netif_device_attach (dev->net);
1530         }
1531         return 0;
1532 }
1533 EXPORT_SYMBOL_GPL(usbnet_suspend);
1534
1535 int usbnet_resume (struct usb_interface *intf)
1536 {
1537         struct usbnet           *dev = usb_get_intfdata(intf);
1538         struct sk_buff          *skb;
1539         struct urb              *res;
1540         int                     retval;
1541
1542         if (!--dev->suspend_count) {
1543                 /* resume interrupt URBs */
1544                 if (dev->interrupt && test_bit(EVENT_DEV_OPEN, &dev->flags))
1545                         usb_submit_urb(dev->interrupt, GFP_NOIO);
1546
1547                 spin_lock_irq(&dev->txq.lock);
1548                 while ((res = usb_get_from_anchor(&dev->deferred))) {
1549
1550                         skb = (struct sk_buff *)res->context;
1551                         retval = usb_submit_urb(res, GFP_ATOMIC);
1552                         if (retval < 0) {
1553                                 dev_kfree_skb_any(skb);
1554                                 usb_free_urb(res);
1555                                 usb_autopm_put_interface_async(dev->intf);
1556                         } else {
1557                                 dev->net->trans_start = jiffies;
1558                                 __skb_queue_tail(&dev->txq, skb);
1559                         }
1560                 }
1561
1562                 smp_mb();
1563                 clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1564                 spin_unlock_irq(&dev->txq.lock);
1565
1566                 if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1567                         if (!(dev->txq.qlen >= TX_QLEN(dev)))
1568                                 netif_start_queue(dev->net);
1569                         tasklet_schedule (&dev->bh);
1570                 }
1571         }
1572         return 0;
1573 }
1574 EXPORT_SYMBOL_GPL(usbnet_resume);
1575
1576
1577 /*-------------------------------------------------------------------------*/
1578
1579 static int __init usbnet_init(void)
1580 {
1581         /* Compiler should optimize this out. */
1582         BUILD_BUG_ON(
1583                 FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
1584
1585         random_ether_addr(node_id);
1586         return 0;
1587 }
1588 module_init(usbnet_init);
1589
1590 static void __exit usbnet_exit(void)
1591 {
1592 }
1593 module_exit(usbnet_exit);
1594
1595 MODULE_AUTHOR("David Brownell");
1596 MODULE_DESCRIPTION("USB network driver framework");
1597 MODULE_LICENSE("GPL");