drivers/usb/gadget/function/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                 DBG(cdev, "reset eem\n");
 199                 gether_disconnect(&eem->port);
 200
 201                 if (!eem->port.in_ep->desc || !eem->port.out_ep->desc) {
 202                         DBG(cdev, "init eem\n");
 203                         if (config_ep_by_speed(cdev->gadget, f,
 204                                                eem->port.in_ep) ||
 205                             config_ep_by_speed(cdev->gadget, f,
 206                                                eem->port.out_ep)) {
 207                                 eem->port.in_ep->desc = NULL;
 208                                 eem->port.out_ep->desc = NULL;
 209                                 goto fail;
 210                         }
 211                 }
 212
 213                 /* zlps should not occur because zero-length EEM packets
 214                  * will be inserted in those cases where they would occur
 215                  */
 216                 eem->port.is_zlp_ok = 1;
 217                 eem->port.cdc_filter = DEFAULT_FILTER;
 218                 DBG(cdev, "activate eem\n");
 219                 net = gether_connect(&eem->port);
 220                 if (IS_ERR(net))
 221                         return PTR_ERR(net);
 222         } else
 223                 goto fail;
 224
 225         return 0;
 226 fail:
 227         return -EINVAL;
 228 }
 229
 230 static void eem_disable(struct usb_function *f)
 231 {
 232         struct f_eem            *eem = func_to_eem(f);
 233         struct usb_composite_dev *cdev = f->config->cdev;
 234
 235         DBG(cdev, "eem deactivated\n");
 236
 237         if (eem->port.in_ep->enabled)
 238                 gether_disconnect(&eem->port);
 239 }
 240
 241 /*-------------------------------------------------------------------------*/
 242
 243 /* EEM function driver setup/binding */
 244
 245 static int eem_bind(struct usb_configuration *c, struct usb_function *f)
 246 {
 247         struct usb_composite_dev *cdev = c->cdev;
 248         struct f_eem            *eem = func_to_eem(f);
 249         struct usb_string       *us;
 250         int                     status;
 251         struct usb_ep           *ep;
 252
 253         struct f_eem_opts       *eem_opts;
 254
 255         eem_opts = container_of(f->fi, struct f_eem_opts, func_inst);
 256         /*
 257          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
 258          * configurations are bound in sequence with list_for_each_entry,
 259          * in each configuration its functions are bound in sequence
 260          * with list_for_each_entry, so we assume no race condition
 261          * with regard to eem_opts->bound access
 262          */
 263         if (!eem_opts->bound) {
 264                 mutex_lock(&eem_opts->lock);
 265                 gether_set_gadget(eem_opts->net, cdev->gadget);
 266                 status = gether_register_netdev(eem_opts->net);
 267                 mutex_unlock(&eem_opts->lock);
 268                 if (status)
 269                         return status;
 270                 eem_opts->bound = true;
 271         }
 272
 273         us = usb_gstrings_attach(cdev, eem_strings,
 274                                  ARRAY_SIZE(eem_string_defs));
 275         if (IS_ERR(us))
 276                 return PTR_ERR(us);
 277         eem_intf.iInterface = us[0].id;
 278
 279         /* allocate instance-specific interface IDs */
 280         status = usb_interface_id(c, f);
 281         if (status < 0)
 282                 goto fail;
 283         eem->ctrl_id = status;
 284         eem_intf.bInterfaceNumber = status;
 285
 286         status = -ENODEV;
 287
 288         /* allocate instance-specific endpoints */
 289         ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_in_desc);
 290         if (!ep)
 291                 goto fail;
 292         eem->port.in_ep = ep;
 293
 294         ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_out_desc);
 295         if (!ep)
 296                 goto fail;
 297         eem->port.out_ep = ep;
 298
 299         status = -ENOMEM;
 300
 301         /* support all relevant hardware speeds... we expect that when
 302          * hardware is dual speed, all bulk-capable endpoints work at
 303          * both speeds
 304          */
 305         eem_hs_in_desc.bEndpointAddress = eem_fs_in_desc.bEndpointAddress;
 306         eem_hs_out_desc.bEndpointAddress = eem_fs_out_desc.bEndpointAddress;
 307
 308         eem_ss_in_desc.bEndpointAddress = eem_fs_in_desc.bEndpointAddress;
 309         eem_ss_out_desc.bEndpointAddress = eem_fs_out_desc.bEndpointAddress;
 310
 311         status = usb_assign_descriptors(f, eem_fs_function, eem_hs_function,
 312                         eem_ss_function, NULL);
 313         if (status)
 314                 goto fail;
 315
 316         DBG(cdev, "CDC Ethernet (EEM): %s speed IN/%s OUT/%s\n",
 317                         gadget_is_superspeed(c->cdev->gadget) ? "super" :
 318                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 319                         eem->port.in_ep->name, eem->port.out_ep->name);
 320         return 0;
 321
 322 fail:
 323         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 324
 325         return status;
 326 }
 327
 328 static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req)
 329 {
 330         struct sk_buff *skb = (struct sk_buff *)req->context;
 331
 332         dev_kfree_skb_any(skb);
 333 }
 334
 335 /*
 336  * Add the EEM header and ethernet checksum.
 337  * We currently do not attempt to put multiple ethernet frames
 338  * into a single USB transfer
 339  */
 340 static struct sk_buff *eem_wrap(struct gether *port, struct sk_buff *skb)
 341 {
 342         struct sk_buff  *skb2 = NULL;
 343         struct usb_ep   *in = port->in_ep;
 344         int             headroom, tailroom, padlen = 0;
 345         u16             len;
 346
 347         if (!skb)
 348                 return NULL;
 349
 350         len = skb->len;
 351         headroom = skb_headroom(skb);
 352         tailroom = skb_tailroom(skb);
 353
 354         /* When (len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) is 0,
 355          * stick two bytes of zero-length EEM packet on the end.
 356          */
 357         if (((len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) == 0)
 358                 padlen += 2;
 359
 360         if ((tailroom >= (ETH_FCS_LEN + padlen)) &&
 361                         (headroom >= EEM_HLEN) && !skb_cloned(skb))
 362                 goto done;
 363
 364         skb2 = skb_copy_expand(skb, EEM_HLEN, ETH_FCS_LEN + padlen, GFP_ATOMIC);
 365         dev_kfree_skb_any(skb);
 366         skb = skb2;
 367         if (!skb)
 368                 return skb;
 369
 370 done:
 371         /* use the "no CRC" option */
 372         put_unaligned_be32(0xdeadbeef, skb_put(skb, 4));
 373
 374         /* EEM packet header format:
 375          * b0..13:      length of ethernet frame
 376          * b14:         bmCRC (0 == sentinel CRC)
 377          * b15:         bmType (0 == data)
 378          */
 379         len = skb->len;
 380         put_unaligned_le16(len & 0x3FFF, skb_push(skb, 2));
 381
 382         /* add a zero-length EEM packet, if needed */
 383         if (padlen)
 384                 put_unaligned_le16(0, skb_put(skb, 2));
 385
 386         return skb;
 387 }
 388
 389 /*
 390  * Remove the EEM header.  Note that there can be many EEM packets in a single
 391  * USB transfer, so we need to break them out and handle them independently.
 392  */
 393 static int eem_unwrap(struct gether *port,
 394                         struct sk_buff *skb,
 395                         struct sk_buff_head *list)
 396 {
 397         struct usb_composite_dev        *cdev = port->func.config->cdev;
 398         int                             status = 0;
 399
 400         do {
 401                 struct sk_buff  *skb2;
 402                 u16             header;
 403                 u16             len = 0;
 404
 405                 if (skb->len < EEM_HLEN) {
 406                         status = -EINVAL;
 407                         DBG(cdev, "invalid EEM header\n");
 408                         goto error;
 409                 }
 410
 411                 /* remove the EEM header */
 412                 header = get_unaligned_le16(skb->data);
 413                 skb_pull(skb, EEM_HLEN);
 414
 415                 /* EEM packet header format:
 416                  * b0..14:      EEM type dependent (data or command)
 417                  * b15:         bmType (0 == data, 1 == command)
 418                  */
 419                 if (header & BIT(15)) {
 420                         struct usb_request      *req = cdev->req;
 421                         u16                     bmEEMCmd;
 422
 423                         /* EEM command packet format:
 424                          * b0..10:      bmEEMCmdParam
 425                          * b11..13:     bmEEMCmd
 426                          * b14:         reserved (must be zero)
 427                          * b15:         bmType (1 == command)
 428                          */
 429                         if (header & BIT(14))
 430                                 continue;
 431
 432                         bmEEMCmd = (header >> 11) & 0x7;
 433                         switch (bmEEMCmd) {
 434                         case 0: /* echo */
 435                                 len = header & 0x7FF;
 436                                 if (skb->len < len) {
 437                                         status = -EOVERFLOW;
 438                                         goto error;
 439                                 }
 440
 441                                 skb2 = skb_clone(skb, GFP_ATOMIC);
 442                                 if (unlikely(!skb2)) {
 443                                         DBG(cdev, "EEM echo response error\n");
 444                                         goto next;
 445                                 }
 446                                 skb_trim(skb2, len);
 447                                 put_unaligned_le16(BIT(15) | BIT(11) | len,
 448                                                         skb_push(skb2, 2));
 449                                 skb_copy_bits(skb2, 0, req->buf, skb2->len);
 450                                 req->length = skb2->len;
 451                                 req->complete = eem_cmd_complete;
 452                                 req->zero = 1;
 453                                 req->context = skb2;
 454                                 if (usb_ep_queue(port->in_ep, req, GFP_ATOMIC))
 455                                         DBG(cdev, "echo response queue fail\n");
 456                                 break;
 457
 458                         case 1:  /* echo response */
 459                         case 2:  /* suspend hint */
 460                         case 3:  /* response hint */
 461                         case 4:  /* response complete hint */
 462                         case 5:  /* tickle */
 463                         default: /* reserved */
 464                                 continue;
 465                         }
 466                 } else {
 467                         u32             crc, crc2;
 468                         struct sk_buff  *skb3;
 469
 470                         /* check for zero-length EEM packet */
 471                         if (header == 0)
 472                                 continue;
 473
 474                         /* EEM data packet format:
 475                          * b0..13:      length of ethernet frame
 476                          * b14:         bmCRC (0 == sentinel, 1 == calculated)
 477                          * b15:         bmType (0 == data)
 478                          */
 479                         len = header & 0x3FFF;
 480                         if ((skb->len < len)
 481                                         || (len < (ETH_HLEN + ETH_FCS_LEN))) {
 482                                 status = -EINVAL;
 483                                 goto error;
 484                         }
 485
 486                         /* validate CRC */
 487                         if (header & BIT(14)) {
 488                                 crc = get_unaligned_le32(skb->data + len
 489                                                         - ETH_FCS_LEN);
 490                                 crc2 = ~crc32_le(~0,
 491                                                 skb->data, len - ETH_FCS_LEN);
 492                         } else {
 493                                 crc = get_unaligned_be32(skb->data + len
 494                                                         - ETH_FCS_LEN);
 495                                 crc2 = 0xdeadbeef;
 496                         }
 497                         if (crc != crc2) {
 498                                 DBG(cdev, "invalid EEM CRC\n");
 499                                 goto next;
 500                         }
 501
 502                         skb2 = skb_clone(skb, GFP_ATOMIC);
 503                         if (unlikely(!skb2)) {
 504                                 DBG(cdev, "unable to unframe EEM packet\n");
 505                                 continue;
 506                         }
 507                         skb_trim(skb2, len - ETH_FCS_LEN);
 508
 509                         skb3 = skb_copy_expand(skb2,
 510                                                 NET_IP_ALIGN,
 511                                                 0,
 512                                                 GFP_ATOMIC);
 513                         if (unlikely(!skb3)) {
 514                                 DBG(cdev, "unable to realign EEM packet\n");
 515                                 dev_kfree_skb_any(skb2);
 516                                 continue;
 517                         }
 518                         dev_kfree_skb_any(skb2);
 519                         skb_queue_tail(list, skb3);
 520                 }
 521 next:
 522                 skb_pull(skb, len);
 523         } while (skb->len);
 524
 525 error:
 526         dev_kfree_skb_any(skb);
 527         return status;
 528 }
 529
 530 static inline struct f_eem_opts *to_f_eem_opts(struct config_item *item)
 531 {
 532         return container_of(to_config_group(item), struct f_eem_opts,
 533                             func_inst.group);
 534 }
 535
 536 /* f_eem_item_ops */
 537 USB_ETHERNET_CONFIGFS_ITEM(eem);
 538
 539 /* f_eem_opts_dev_addr */
 540 USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(eem);
 541
 542 /* f_eem_opts_host_addr */
 543 USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(eem);
 544
 545 /* f_eem_opts_qmult */
 546 USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(eem);
 547
 548 /* f_eem_opts_ifname */
 549 USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(eem);
 550
 551 static struct configfs_attribute *eem_attrs[] = {
 552         &eem_opts_attr_dev_addr,
 553         &eem_opts_attr_host_addr,
 554         &eem_opts_attr_qmult,
 555         &eem_opts_attr_ifname,
 556         NULL,
 557 };
 558
 559 static struct config_item_type eem_func_type = {
 560         .ct_item_ops    = &eem_item_ops,
 561         .ct_attrs       = eem_attrs,
 562         .ct_owner       = THIS_MODULE,
 563 };
 564
 565 static void eem_free_inst(struct usb_function_instance *f)
 566 {
 567         struct f_eem_opts *opts;
 568
 569         opts = container_of(f, struct f_eem_opts, func_inst);
 570         if (opts->bound)
 571                 gether_cleanup(netdev_priv(opts->net));
 572         else
 573                 free_netdev(opts->net);
 574         kfree(opts);
 575 }
 576
 577 static struct usb_function_instance *eem_alloc_inst(void)
 578 {
 579         struct f_eem_opts *opts;
 580
 581         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 582         if (!opts)
 583                 return ERR_PTR(-ENOMEM);
 584         mutex_init(&opts->lock);
 585         opts->func_inst.free_func_inst = eem_free_inst;
 586         opts->net = gether_setup_default();
 587         if (IS_ERR(opts->net)) {
 588                 struct net_device *net = opts->net;
 589                 kfree(opts);
 590                 return ERR_CAST(net);
 591         }
 592
 593         config_group_init_type_name(&opts->func_inst.group, "", &eem_func_type);
 594
 595         return &opts->func_inst;
 596 }
 597
 598 static void eem_free(struct usb_function *f)
 599 {
 600         struct f_eem *eem;
 601         struct f_eem_opts *opts;
 602
 603         eem = func_to_eem(f);
 604         opts = container_of(f->fi, struct f_eem_opts, func_inst);
 605         kfree(eem);
 606         mutex_lock(&opts->lock);
 607         opts->refcnt--;
 608         mutex_unlock(&opts->lock);
 609 }
 610
 611 static void eem_unbind(struct usb_configuration *c, struct usb_function *f)
 612 {
 613         DBG(c->cdev, "eem unbind\n");
 614
 615         usb_free_all_descriptors(f);
 616 }
 617
 618 static struct usb_function *eem_alloc(struct usb_function_instance *fi)
 619 {
 620         struct f_eem    *eem;
 621         struct f_eem_opts *opts;
 622
 623         /* allocate and initialize one new instance */
 624         eem = kzalloc(sizeof(*eem), GFP_KERNEL);
 625         if (!eem)
 626                 return ERR_PTR(-ENOMEM);
 627
 628         opts = container_of(fi, struct f_eem_opts, func_inst);
 629         mutex_lock(&opts->lock);
 630         opts->refcnt++;
 631
 632         eem->port.ioport = netdev_priv(opts->net);
 633         mutex_unlock(&opts->lock);
 634         eem->port.cdc_filter = DEFAULT_FILTER;
 635
 636         eem->port.func.name = "cdc_eem";
 637         /* descriptors are per-instance copies */
 638         eem->port.func.bind = eem_bind;
 639         eem->port.func.unbind = eem_unbind;
 640         eem->port.func.set_alt = eem_set_alt;
 641         eem->port.func.setup = eem_setup;
 642         eem->port.func.disable = eem_disable;
 643         eem->port.func.free_func = eem_free;
 644         eem->port.wrap = eem_wrap;
 645         eem->port.unwrap = eem_unwrap;
 646         eem->port.header_len = EEM_HLEN;
 647
 648         return &eem->port.func;
 649 }
 650
 651 DECLARE_USB_FUNCTION_INIT(eem, eem_alloc_inst, eem_alloc);
 652 MODULE_LICENSE("GPL");
 653 MODULE_AUTHOR("David Brownell");