drivers/usb/gadget/f_eem.c

   1 /*
   2  * f_eem.c -- USB CDC Ethernet (EEM) link function driver
   3  *
   4  * Copyright (C) 2003-2005,2008 David Brownell
   5  * Copyright (C) 2008 Nokia Corporation
   6  * Copyright (C) 2009 EF Johnson Technologies
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/device.h>
  17 #include <linux/etherdevice.h>
  18 #include <linux/crc32.h>
  19 #include <linux/slab.h>
  20
  21 #include "u_ether.h"
  22 #include "u_ether_configfs.h"
  23 #include "u_eem.h"
  24
  25 #define EEM_HLEN 2
  26
  27 /*
  28  * This function is a "CDC Ethernet Emulation Model" (CDC EEM)
  29  * Ethernet link.
  30  */
  31
  32 struct f_eem {
  33         struct gether                   port;
  34         u8                              ctrl_id;
  35 };
  36
  37 static inline struct f_eem *func_to_eem(struct usb_function *f)
  38 {
  39         return container_of(f, struct f_eem, port.func);
  40 }
  41
  42 /*-------------------------------------------------------------------------*/
  43
  44 /* interface descriptor: */
  45
  46 static struct usb_interface_descriptor eem_intf = {
  47         .bLength =              sizeof eem_intf,
  48         .bDescriptorType =      USB_DT_INTERFACE,
  49
  50         /* .bInterfaceNumber = DYNAMIC */
  51         .bNumEndpoints =        2,
  52         .bInterfaceClass =      USB_CLASS_COMM,
  53         .bInterfaceSubClass =   USB_CDC_SUBCLASS_EEM,
  54         .bInterfaceProtocol =   USB_CDC_PROTO_EEM,
  55         /* .iInterface = DYNAMIC */
  56 };
  57
  58 /* full speed support: */
  59
  60 static struct usb_endpoint_descriptor eem_fs_in_desc = {
  61         .bLength =              USB_DT_ENDPOINT_SIZE,
  62         .bDescriptorType =      USB_DT_ENDPOINT,
  63
  64         .bEndpointAddress =     USB_DIR_IN,
  65         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  66 };
  67
  68 static struct usb_endpoint_descriptor eem_fs_out_desc = {
  69         .bLength =              USB_DT_ENDPOINT_SIZE,
  70         .bDescriptorType =      USB_DT_ENDPOINT,
  71
  72         .bEndpointAddress =     USB_DIR_OUT,
  73         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  74 };
  75
  76 static struct usb_descriptor_header *eem_fs_function[] = {
  77         /* CDC EEM control descriptors */
  78         (struct usb_descriptor_header *) &eem_intf,
  79         (struct usb_descriptor_header *) &eem_fs_in_desc,
  80         (struct usb_descriptor_header *) &eem_fs_out_desc,
  81         NULL,
  82 };
  83
  84 /* high speed support: */
  85
  86 static struct usb_endpoint_descriptor eem_hs_in_desc = {
  87         .bLength =              USB_DT_ENDPOINT_SIZE,
  88         .bDescriptorType =      USB_DT_ENDPOINT,
  89
  90         .bEndpointAddress =     USB_DIR_IN,
  91         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  92         .wMaxPacketSize =       cpu_to_le16(512),
  93 };
  94
  95 static struct usb_endpoint_descriptor eem_hs_out_desc = {
  96         .bLength =              USB_DT_ENDPOINT_SIZE,
  97         .bDescriptorType =      USB_DT_ENDPOINT,
  98
  99         .bEndpointAddress =     USB_DIR_OUT,
 100         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 101         .wMaxPacketSize =       cpu_to_le16(512),
 102 };
 103
 104 static struct usb_descriptor_header *eem_hs_function[] = {
 105         /* CDC EEM control descriptors */
 106         (struct usb_descriptor_header *) &eem_intf,
 107         (struct usb_descriptor_header *) &eem_hs_in_desc,
 108         (struct usb_descriptor_header *) &eem_hs_out_desc,
 109         NULL,
 110 };
 111
 112 /* super speed support: */
 113
 114 static struct usb_endpoint_descriptor eem_ss_in_desc = {
 115         .bLength =              USB_DT_ENDPOINT_SIZE,
 116         .bDescriptorType =      USB_DT_ENDPOINT,
 117
 118         .bEndpointAddress =     USB_DIR_IN,
 119         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 120         .wMaxPacketSize =       cpu_to_le16(1024),
 121 };
 122
 123 static struct usb_endpoint_descriptor eem_ss_out_desc = {
 124         .bLength =              USB_DT_ENDPOINT_SIZE,
 125         .bDescriptorType =      USB_DT_ENDPOINT,
 126
 127         .bEndpointAddress =     USB_DIR_OUT,
 128         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 129         .wMaxPacketSize =       cpu_to_le16(1024),
 130 };
 131
 132 static struct usb_ss_ep_comp_descriptor eem_ss_bulk_comp_desc = {
 133         .bLength =              sizeof eem_ss_bulk_comp_desc,
 134         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 135
 136         /* the following 2 values can be tweaked if necessary */
 137         /* .bMaxBurst =         0, */
 138         /* .bmAttributes =      0, */
 139 };
 140
 141 static struct usb_descriptor_header *eem_ss_function[] = {
 142         /* CDC EEM control descriptors */
 143         (struct usb_descriptor_header *) &eem_intf,
 144         (struct usb_descriptor_header *) &eem_ss_in_desc,
 145         (struct usb_descriptor_header *) &eem_ss_bulk_comp_desc,
 146         (struct usb_descriptor_header *) &eem_ss_out_desc,
 147         (struct usb_descriptor_header *) &eem_ss_bulk_comp_desc,
 148         NULL,
 149 };
 150
 151 /* string descriptors: */
 152
 153 static struct usb_string eem_string_defs[] = {
 154         [0].s = "CDC Ethernet Emulation Model (EEM)",
 155         {  } /* end of list */
 156 };
 157
 158 static struct usb_gadget_strings eem_string_table = {
 159         .language =             0x0409, /* en-us */
 160         .strings =              eem_string_defs,
 161 };
 162
 163 static struct usb_gadget_strings *eem_strings[] = {
 164         &eem_string_table,
 165         NULL,
 166 };
 167
 168 /*-------------------------------------------------------------------------*/
 169
 170 static int eem_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 171 {
 172         struct usb_composite_dev *cdev = f->config->cdev;
 173         int                     value = -EOPNOTSUPP;
 174         u16                     w_index = le16_to_cpu(ctrl->wIndex);
 175         u16                     w_value = le16_to_cpu(ctrl->wValue);
 176         u16                     w_length = le16_to_cpu(ctrl->wLength);
 177
 178         DBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
 179                 ctrl->bRequestType, ctrl->bRequest,
 180                 w_value, w_index, w_length);
 181
 182         /* device either stalls (value < 0) or reports success */
 183         return value;
 184 }
 185
 186
 187 static int eem_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 188 {
 189         struct f_eem            *eem = func_to_eem(f);
 190         struct usb_composite_dev *cdev = f->config->cdev;
 191         struct net_device       *net;
 192
 193         /* we know alt == 0, so this is an activation or a reset */
 194         if (alt != 0)
 195                 goto fail;
 196
 197         if (intf == eem->ctrl_id) {
 198
 199                 if (eem->port.in_ep->driver_data) {
 200                         DBG(cdev, "reset eem\n");
 201                         gether_disconnect(&eem->port);
 202                 }
 203
 204                 if (!eem->port.in_ep->desc || !eem->port.out_ep->desc) {
 205                         DBG(cdev, "init eem\n");
 206                         if (config_ep_by_speed(cdev->gadget, f,
 207                                                eem->port.in_ep) ||
 208                             config_ep_by_speed(cdev->gadget, f,
 209                                                eem->port.out_ep)) {
 210                                 eem->port.in_ep->desc = NULL;
 211                                 eem->port.out_ep->desc = NULL;
 212                                 goto fail;
 213                         }
 214                 }
 215
 216                 /* zlps should not occur because zero-length EEM packets
 217                  * will be inserted in those cases where they would occur
 218                  */
 219                 eem->port.is_zlp_ok = 1;
 220                 eem->port.cdc_filter = DEFAULT_FILTER;
 221                 DBG(cdev, "activate eem\n");
 222                 net = gether_connect(&eem->port);
 223                 if (IS_ERR(net))
 224                         return PTR_ERR(net);
 225         } else
 226                 goto fail;
 227
 228         return 0;
 229 fail:
 230         return -EINVAL;
 231 }
 232
 233 static void eem_disable(struct usb_function *f)
 234 {
 235         struct f_eem            *eem = func_to_eem(f);
 236         struct usb_composite_dev *cdev = f->config->cdev;
 237
 238         DBG(cdev, "eem deactivated\n");
 239
 240         if (eem->port.in_ep->driver_data)
 241                 gether_disconnect(&eem->port);
 242 }
 243
 244 /*-------------------------------------------------------------------------*/
 245
 246 /* EEM function driver setup/binding */
 247
 248 static int eem_bind(struct usb_configuration *c, struct usb_function *f)
 249 {
 250         struct usb_composite_dev *cdev = c->cdev;
 251         struct f_eem            *eem = func_to_eem(f);
 252         struct usb_string       *us;
 253         int                     status;
 254         struct usb_ep           *ep;
 255
 256         struct f_eem_opts       *eem_opts;
 257
 258         eem_opts = container_of(f->fi, struct f_eem_opts, func_inst);
 259         /*
 260          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
 261          * configurations are bound in sequence with list_for_each_entry,
 262          * in each configuration its functions are bound in sequence
 263          * with list_for_each_entry, so we assume no race condition
 264          * with regard to eem_opts->bound access
 265          */
 266         if (!eem_opts->bound) {
 267                 mutex_lock(&eem_opts->lock);
 268                 gether_set_gadget(eem_opts->net, cdev->gadget);
 269                 status = gether_register_netdev(eem_opts->net);
 270                 mutex_unlock(&eem_opts->lock);
 271                 if (status)
 272                         return status;
 273                 eem_opts->bound = true;
 274         }
 275
 276         us = usb_gstrings_attach(cdev, eem_strings,
 277                                  ARRAY_SIZE(eem_string_defs));
 278         if (IS_ERR(us))
 279                 return PTR_ERR(us);
 280         eem_intf.iInterface = us[0].id;
 281
 282         /* allocate instance-specific interface IDs */
 283         status = usb_interface_id(c, f);
 284         if (status < 0)
 285                 goto fail;
 286         eem->ctrl_id = status;
 287         eem_intf.bInterfaceNumber = status;
 288
 289         status = -ENODEV;
 290
 291         /* allocate instance-specific endpoints */
 292         ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_in_desc);
 293         if (!ep)
 294                 goto fail;
 295         eem->port.in_ep = ep;
 296         ep->driver_data = cdev; /* claim */
 297
 298         ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_out_desc);
 299         if (!ep)
 300                 goto fail;
 301         eem->port.out_ep = ep;
 302         ep->driver_data = cdev; /* claim */
 303
 304         status = -ENOMEM;
 305
 306         /* support all relevant hardware speeds... we expect that when
 307          * hardware is dual speed, all bulk-capable endpoints work at
 308          * both speeds
 309          */
 310         eem_hs_in_desc.bEndpointAddress = eem_fs_in_desc.bEndpointAddress;
 311         eem_hs_out_desc.bEndpointAddress = eem_fs_out_desc.bEndpointAddress;
 312
 313         eem_ss_in_desc.bEndpointAddress = eem_fs_in_desc.bEndpointAddress;
 314         eem_ss_out_desc.bEndpointAddress = eem_fs_out_desc.bEndpointAddress;
 315
 316         status = usb_assign_descriptors(f, eem_fs_function, eem_hs_function,
 317                         eem_ss_function);
 318         if (status)
 319                 goto fail;
 320
 321         DBG(cdev, "CDC Ethernet (EEM): %s speed IN/%s OUT/%s\n",
 322                         gadget_is_superspeed(c->cdev->gadget) ? "super" :
 323                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 324                         eem->port.in_ep->name, eem->port.out_ep->name);
 325         return 0;
 326
 327 fail:
 328         usb_free_all_descriptors(f);
 329         if (eem->port.out_ep)
 330                 eem->port.out_ep->driver_data = NULL;
 331         if (eem->port.in_ep)
 332                 eem->port.in_ep->driver_data = NULL;
 333
 334         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 335
 336         return status;
 337 }
 338
 339 static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req)
 340 {
 341         struct sk_buff *skb = (struct sk_buff *)req->context;
 342
 343         dev_kfree_skb_any(skb);
 344 }
 345
 346 /*
 347  * Add the EEM header and ethernet checksum.
 348  * We currently do not attempt to put multiple ethernet frames
 349  * into a single USB transfer
 350  */
 351 static struct sk_buff *eem_wrap(struct gether *port, struct sk_buff *skb)
 352 {
 353         struct sk_buff  *skb2 = NULL;
 354         struct usb_ep   *in = port->in_ep;
 355         int             padlen = 0;
 356         u16             len = skb->len;
 357
 358         if (!skb_cloned(skb)) {
 359                 int headroom = skb_headroom(skb);
 360                 int tailroom = skb_tailroom(skb);
 361
 362                 /* When (len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) is 0,
 363                  * stick two bytes of zero-length EEM packet on the end.
 364                  */
 365                 if (((len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) == 0)
 366                         padlen += 2;
 367
 368                 if ((tailroom >= (ETH_FCS_LEN + padlen)) &&
 369                                 (headroom >= EEM_HLEN))
 370                         goto done;
 371         }
 372
 373         skb2 = skb_copy_expand(skb, EEM_HLEN, ETH_FCS_LEN + padlen, GFP_ATOMIC);
 374         dev_kfree_skb_any(skb);
 375         skb = skb2;
 376         if (!skb)
 377                 return skb;
 378
 379 done:
 380         /* use the "no CRC" option */
 381         put_unaligned_be32(0xdeadbeef, skb_put(skb, 4));
 382
 383         /* EEM packet header format:
 384          * b0..13:      length of ethernet frame
 385          * b14:         bmCRC (0 == sentinel CRC)
 386          * b15:         bmType (0 == data)
 387          */
 388         len = skb->len;
 389         put_unaligned_le16(len & 0x3FFF, skb_push(skb, 2));
 390
 391         /* add a zero-length EEM packet, if needed */
 392         if (padlen)
 393                 put_unaligned_le16(0, skb_put(skb, 2));
 394
 395         return skb;
 396 }
 397
 398 /*
 399  * Remove the EEM header.  Note that there can be many EEM packets in a single
 400  * USB transfer, so we need to break them out and handle them independently.
 401  */
 402 static int eem_unwrap(struct gether *port,
 403                         struct sk_buff *skb,
 404                         struct sk_buff_head *list)
 405 {
 406         struct usb_composite_dev        *cdev = port->func.config->cdev;
 407         int                             status = 0;
 408
 409         do {
 410                 struct sk_buff  *skb2;
 411                 u16             header;
 412                 u16             len = 0;
 413
 414                 if (skb->len < EEM_HLEN) {
 415                         status = -EINVAL;
 416                         DBG(cdev, "invalid EEM header\n");
 417                         goto error;
 418                 }
 419
 420                 /* remove the EEM header */
 421                 header = get_unaligned_le16(skb->data);
 422                 skb_pull(skb, EEM_HLEN);
 423
 424                 /* EEM packet header format:
 425                  * b0..14:      EEM type dependent (data or command)
 426                  * b15:         bmType (0 == data, 1 == command)
 427                  */
 428                 if (header & BIT(15)) {
 429                         struct usb_request      *req = cdev->req;
 430                         u16                     bmEEMCmd;
 431
 432                         /* EEM command packet format:
 433                          * b0..10:      bmEEMCmdParam
 434                          * b11..13:     bmEEMCmd
 435                          * b14:         reserved (must be zero)
 436                          * b15:         bmType (1 == command)
 437                          */
 438                         if (header & BIT(14))
 439                                 continue;
 440
 441                         bmEEMCmd = (header >> 11) & 0x7;
 442                         switch (bmEEMCmd) {
 443                         case 0: /* echo */
 444                                 len = header & 0x7FF;
 445                                 if (skb->len < len) {
 446                                         status = -EOVERFLOW;
 447                                         goto error;
 448                                 }
 449
 450                                 skb2 = skb_clone(skb, GFP_ATOMIC);
 451                                 if (unlikely(!skb2)) {
 452                                         DBG(cdev, "EEM echo response error\n");
 453                                         goto next;
 454                                 }
 455                                 skb_trim(skb2, len);
 456                                 put_unaligned_le16(BIT(15) | BIT(11) | len,
 457                                                         skb_push(skb2, 2));
 458                                 skb_copy_bits(skb2, 0, req->buf, skb2->len);
 459                                 req->length = skb2->len;
 460                                 req->complete = eem_cmd_complete;
 461                                 req->zero = 1;
 462                                 req->context = skb2;
 463                                 if (usb_ep_queue(port->in_ep, req, GFP_ATOMIC))
 464                                         DBG(cdev, "echo response queue fail\n");
 465                                 break;
 466
 467                         case 1:  /* echo response */
 468                         case 2:  /* suspend hint */
 469                         case 3:  /* response hint */
 470                         case 4:  /* response complete hint */
 471                         case 5:  /* tickle */
 472                         default: /* reserved */
 473                                 continue;
 474                         }
 475                 } else {
 476                         u32             crc, crc2;
 477                         struct sk_buff  *skb3;
 478
 479                         /* check for zero-length EEM packet */
 480                         if (header == 0)
 481                                 continue;
 482
 483                         /* EEM data packet format:
 484                          * b0..13:      length of ethernet frame
 485                          * b14:         bmCRC (0 == sentinel, 1 == calculated)
 486                          * b15:         bmType (0 == data)
 487                          */
 488                         len = header & 0x3FFF;
 489                         if ((skb->len < len)
 490                                         || (len < (ETH_HLEN + ETH_FCS_LEN))) {
 491                                 status = -EINVAL;
 492                                 goto error;
 493                         }
 494
 495                         /* validate CRC */
 496                         if (header & BIT(14)) {
 497                                 crc = get_unaligned_le32(skb->data + len
 498                                                         - ETH_FCS_LEN);
 499                                 crc2 = ~crc32_le(~0,
 500                                                 skb->data, len - ETH_FCS_LEN);
 501                         } else {
 502                                 crc = get_unaligned_be32(skb->data + len
 503                                                         - ETH_FCS_LEN);
 504                                 crc2 = 0xdeadbeef;
 505                         }
 506                         if (crc != crc2) {
 507                                 DBG(cdev, "invalid EEM CRC\n");
 508                                 goto next;
 509                         }
 510
 511                         skb2 = skb_clone(skb, GFP_ATOMIC);
 512                         if (unlikely(!skb2)) {
 513                                 DBG(cdev, "unable to unframe EEM packet\n");
 514                                 continue;
 515                         }
 516                         skb_trim(skb2, len - ETH_FCS_LEN);
 517
 518                         skb3 = skb_copy_expand(skb2,
 519                                                 NET_IP_ALIGN,
 520                                                 0,
 521                                                 GFP_ATOMIC);
 522                         if (unlikely(!skb3)) {
 523                                 DBG(cdev, "unable to realign EEM packet\n");
 524                                 dev_kfree_skb_any(skb2);
 525                                 continue;
 526                         }
 527                         dev_kfree_skb_any(skb2);
 528                         skb_queue_tail(list, skb3);
 529                 }
 530 next:
 531                 skb_pull(skb, len);
 532         } while (skb->len);
 533
 534 error:
 535         dev_kfree_skb_any(skb);
 536         return status;
 537 }
 538
 539 static inline struct f_eem_opts *to_f_eem_opts(struct config_item *item)
 540 {
 541         return container_of(to_config_group(item), struct f_eem_opts,
 542                             func_inst.group);
 543 }
 544
 545 /* f_eem_item_ops */
 546 USB_ETHERNET_CONFIGFS_ITEM(eem);
 547
 548 /* f_eem_opts_dev_addr */
 549 USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(eem);
 550
 551 /* f_eem_opts_host_addr */
 552 USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(eem);
 553
 554 /* f_eem_opts_qmult */
 555 USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(eem);
 556
 557 /* f_eem_opts_ifname */
 558 USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(eem);
 559
 560 static struct configfs_attribute *eem_attrs[] = {
 561         &f_eem_opts_dev_addr.attr,
 562         &f_eem_opts_host_addr.attr,
 563         &f_eem_opts_qmult.attr,
 564         &f_eem_opts_ifname.attr,
 565         NULL,
 566 };
 567
 568 static struct config_item_type eem_func_type = {
 569         .ct_item_ops    = &eem_item_ops,
 570         .ct_attrs       = eem_attrs,
 571         .ct_owner       = THIS_MODULE,
 572 };
 573
 574 static void eem_free_inst(struct usb_function_instance *f)
 575 {
 576         struct f_eem_opts *opts;
 577
 578         opts = container_of(f, struct f_eem_opts, func_inst);
 579         if (opts->bound)
 580                 gether_cleanup(netdev_priv(opts->net));
 581         else
 582                 free_netdev(opts->net);
 583         kfree(opts);
 584 }
 585
 586 static struct usb_function_instance *eem_alloc_inst(void)
 587 {
 588         struct f_eem_opts *opts;
 589
 590         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 591         if (!opts)
 592                 return ERR_PTR(-ENOMEM);
 593         mutex_init(&opts->lock);
 594         opts->func_inst.free_func_inst = eem_free_inst;
 595         opts->net = gether_setup_default();
 596         if (IS_ERR(opts->net)) {
 597                 struct net_device *net = opts->net;
 598                 kfree(opts);
 599                 return ERR_CAST(net);
 600         }
 601
 602         config_group_init_type_name(&opts->func_inst.group, "", &eem_func_type);
 603
 604         return &opts->func_inst;
 605 }
 606
 607 static void eem_free(struct usb_function *f)
 608 {
 609         struct f_eem *eem;
 610         struct f_eem_opts *opts;
 611
 612         eem = func_to_eem(f);
 613         opts = container_of(f->fi, struct f_eem_opts, func_inst);
 614         kfree(eem);
 615         mutex_lock(&opts->lock);
 616         opts->refcnt--;
 617         mutex_unlock(&opts->lock);
 618 }
 619
 620 static void eem_unbind(struct usb_configuration *c, struct usb_function *f)
 621 {
 622         DBG(c->cdev, "eem unbind\n");
 623
 624         usb_free_all_descriptors(f);
 625 }
 626
 627 struct usb_function *eem_alloc(struct usb_function_instance *fi)
 628 {
 629         struct f_eem    *eem;
 630         struct f_eem_opts *opts;
 631
 632         /* allocate and initialize one new instance */
 633         eem = kzalloc(sizeof(*eem), GFP_KERNEL);
 634         if (!eem)
 635                 return ERR_PTR(-ENOMEM);
 636
 637         opts = container_of(fi, struct f_eem_opts, func_inst);
 638         mutex_lock(&opts->lock);
 639         opts->refcnt++;
 640
 641         eem->port.ioport = netdev_priv(opts->net);
 642         mutex_unlock(&opts->lock);
 643         eem->port.cdc_filter = DEFAULT_FILTER;
 644
 645         eem->port.func.name = "cdc_eem";
 646         /* descriptors are per-instance copies */
 647         eem->port.func.bind = eem_bind;
 648         eem->port.func.unbind = eem_unbind;
 649         eem->port.func.set_alt = eem_set_alt;
 650         eem->port.func.setup = eem_setup;
 651         eem->port.func.disable = eem_disable;
 652         eem->port.func.free_func = eem_free;
 653         eem->port.wrap = eem_wrap;
 654         eem->port.unwrap = eem_unwrap;
 655         eem->port.header_len = EEM_HLEN;
 656
 657         return &eem->port.func;
 658 }
 659
 660 DECLARE_USB_FUNCTION_INIT(eem, eem_alloc_inst, eem_alloc);
 661 MODULE_LICENSE("GPL");
 662 MODULE_AUTHOR("David Brownell");