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 struct in_context {
  38         struct sk_buff  *skb;
  39         struct usb_ep   *ep;
  40 };
  41
  42 static inline struct f_eem *func_to_eem(struct usb_function *f)
  43 {
  44         return container_of(f, struct f_eem, port.func);
  45 }
  46
  47 /*-------------------------------------------------------------------------*/
  48
  49 /* interface descriptor: */
  50
  51 static struct usb_interface_descriptor eem_intf = {
  52         .bLength =              sizeof eem_intf,
  53         .bDescriptorType =      USB_DT_INTERFACE,
  54
  55         /* .bInterfaceNumber = DYNAMIC */
  56         .bNumEndpoints =        2,
  57         .bInterfaceClass =      USB_CLASS_COMM,
  58         .bInterfaceSubClass =   USB_CDC_SUBCLASS_EEM,
  59         .bInterfaceProtocol =   USB_CDC_PROTO_EEM,
  60         /* .iInterface = DYNAMIC */
  61 };
  62
  63 /* full speed support: */
  64
  65 static struct usb_endpoint_descriptor eem_fs_in_desc = {
  66         .bLength =              USB_DT_ENDPOINT_SIZE,
  67         .bDescriptorType =      USB_DT_ENDPOINT,
  68
  69         .bEndpointAddress =     USB_DIR_IN,
  70         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  71 };
  72
  73 static struct usb_endpoint_descriptor eem_fs_out_desc = {
  74         .bLength =              USB_DT_ENDPOINT_SIZE,
  75         .bDescriptorType =      USB_DT_ENDPOINT,
  76
  77         .bEndpointAddress =     USB_DIR_OUT,
  78         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  79 };
  80
  81 static struct usb_descriptor_header *eem_fs_function[] = {
  82         /* CDC EEM control descriptors */
  83         (struct usb_descriptor_header *) &eem_intf,
  84         (struct usb_descriptor_header *) &eem_fs_in_desc,
  85         (struct usb_descriptor_header *) &eem_fs_out_desc,
  86         NULL,
  87 };
  88
  89 /* high speed support: */
  90
  91 static struct usb_endpoint_descriptor eem_hs_in_desc = {
  92         .bLength =              USB_DT_ENDPOINT_SIZE,
  93         .bDescriptorType =      USB_DT_ENDPOINT,
  94
  95         .bEndpointAddress =     USB_DIR_IN,
  96         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  97         .wMaxPacketSize =       cpu_to_le16(512),
  98 };
  99
 100 static struct usb_endpoint_descriptor eem_hs_out_desc = {
 101         .bLength =              USB_DT_ENDPOINT_SIZE,
 102         .bDescriptorType =      USB_DT_ENDPOINT,
 103
 104         .bEndpointAddress =     USB_DIR_OUT,
 105         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 106         .wMaxPacketSize =       cpu_to_le16(512),
 107 };
 108
 109 static struct usb_descriptor_header *eem_hs_function[] = {
 110         /* CDC EEM control descriptors */
 111         (struct usb_descriptor_header *) &eem_intf,
 112         (struct usb_descriptor_header *) &eem_hs_in_desc,
 113         (struct usb_descriptor_header *) &eem_hs_out_desc,
 114         NULL,
 115 };
 116
 117 /* super speed support: */
 118
 119 static struct usb_endpoint_descriptor eem_ss_in_desc = {
 120         .bLength =              USB_DT_ENDPOINT_SIZE,
 121         .bDescriptorType =      USB_DT_ENDPOINT,
 122
 123         .bEndpointAddress =     USB_DIR_IN,
 124         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 125         .wMaxPacketSize =       cpu_to_le16(1024),
 126 };
 127
 128 static struct usb_endpoint_descriptor eem_ss_out_desc = {
 129         .bLength =              USB_DT_ENDPOINT_SIZE,
 130         .bDescriptorType =      USB_DT_ENDPOINT,
 131
 132         .bEndpointAddress =     USB_DIR_OUT,
 133         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 134         .wMaxPacketSize =       cpu_to_le16(1024),
 135 };
 136
 137 static struct usb_ss_ep_comp_descriptor eem_ss_bulk_comp_desc = {
 138         .bLength =              sizeof eem_ss_bulk_comp_desc,
 139         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 140
 141         /* the following 2 values can be tweaked if necessary */
 142         /* .bMaxBurst =         0, */
 143         /* .bmAttributes =      0, */
 144 };
 145
 146 static struct usb_descriptor_header *eem_ss_function[] = {
 147         /* CDC EEM control descriptors */
 148         (struct usb_descriptor_header *) &eem_intf,
 149         (struct usb_descriptor_header *) &eem_ss_in_desc,
 150         (struct usb_descriptor_header *) &eem_ss_bulk_comp_desc,
 151         (struct usb_descriptor_header *) &eem_ss_out_desc,
 152         (struct usb_descriptor_header *) &eem_ss_bulk_comp_desc,
 153         NULL,
 154 };
 155
 156 /* string descriptors: */
 157
 158 static struct usb_string eem_string_defs[] = {
 159         [0].s = "CDC Ethernet Emulation Model (EEM)",
 160         {  } /* end of list */
 161 };
 162
 163 static struct usb_gadget_strings eem_string_table = {
 164         .language =             0x0409, /* en-us */
 165         .strings =              eem_string_defs,
 166 };
 167
 168 static struct usb_gadget_strings *eem_strings[] = {
 169         &eem_string_table,
 170         NULL,
 171 };
 172
 173 /*-------------------------------------------------------------------------*/
 174
 175 static int eem_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 176 {
 177         struct usb_composite_dev *cdev = f->config->cdev;
 178         int                     value = -EOPNOTSUPP;
 179         u16                     w_index = le16_to_cpu(ctrl->wIndex);
 180         u16                     w_value = le16_to_cpu(ctrl->wValue);
 181         u16                     w_length = le16_to_cpu(ctrl->wLength);
 182
 183         DBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
 184                 ctrl->bRequestType, ctrl->bRequest,
 185                 w_value, w_index, w_length);
 186
 187         /* device either stalls (value < 0) or reports success */
 188         return value;
 189 }
 190
 191
 192 static int eem_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 193 {
 194         struct f_eem            *eem = func_to_eem(f);
 195         struct usb_composite_dev *cdev = f->config->cdev;
 196         struct net_device       *net;
 197
 198         /* we know alt == 0, so this is an activation or a reset */
 199         if (alt != 0)
 200                 goto fail;
 201
 202         if (intf == eem->ctrl_id) {
 203                 DBG(cdev, "reset eem\n");
 204                 gether_disconnect(&eem->port);
 205
 206                 if (!eem->port.in_ep->desc || !eem->port.out_ep->desc) {
 207                         DBG(cdev, "init eem\n");
 208                         if (config_ep_by_speed(cdev->gadget, f,
 209                                                eem->port.in_ep) ||
 210                             config_ep_by_speed(cdev->gadget, f,
 211                                                eem->port.out_ep)) {
 212                                 eem->port.in_ep->desc = NULL;
 213                                 eem->port.out_ep->desc = NULL;
 214                                 goto fail;
 215                         }
 216                 }
 217
 218                 /* zlps should not occur because zero-length EEM packets
 219                  * will be inserted in those cases where they would occur
 220                  */
 221                 eem->port.is_zlp_ok = 1;
 222                 eem->port.cdc_filter = DEFAULT_FILTER;
 223                 DBG(cdev, "activate eem\n");
 224                 net = gether_connect(&eem->port);
 225                 if (IS_ERR(net))
 226                         return PTR_ERR(net);
 227         } else
 228                 goto fail;
 229
 230         return 0;
 231 fail:
 232         return -EINVAL;
 233 }
 234
 235 static void eem_disable(struct usb_function *f)
 236 {
 237         struct f_eem            *eem = func_to_eem(f);
 238         struct usb_composite_dev *cdev = f->config->cdev;
 239
 240         DBG(cdev, "eem deactivated\n");
 241
 242         if (eem->port.in_ep->enabled)
 243                 gether_disconnect(&eem->port);
 244 }
 245
 246 /*-------------------------------------------------------------------------*/
 247
 248 /* EEM function driver setup/binding */
 249
 250 static int eem_bind(struct usb_configuration *c, struct usb_function *f)
 251 {
 252         struct usb_composite_dev *cdev = c->cdev;
 253         struct f_eem            *eem = func_to_eem(f);
 254         struct usb_string       *us;
 255         int                     status;
 256         struct usb_ep           *ep;
 257
 258         struct f_eem_opts       *eem_opts;
 259
 260         eem_opts = container_of(f->fi, struct f_eem_opts, func_inst);
 261         /*
 262          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
 263          * configurations are bound in sequence with list_for_each_entry,
 264          * in each configuration its functions are bound in sequence
 265          * with list_for_each_entry, so we assume no race condition
 266          * with regard to eem_opts->bound access
 267          */
 268         if (!eem_opts->bound) {
 269                 mutex_lock(&eem_opts->lock);
 270                 gether_set_gadget(eem_opts->net, cdev->gadget);
 271                 status = gether_register_netdev(eem_opts->net);
 272                 mutex_unlock(&eem_opts->lock);
 273                 if (status)
 274                         return status;
 275                 eem_opts->bound = true;
 276         }
 277
 278         us = usb_gstrings_attach(cdev, eem_strings,
 279                                  ARRAY_SIZE(eem_string_defs));
 280         if (IS_ERR(us))
 281                 return PTR_ERR(us);
 282         eem_intf.iInterface = us[0].id;
 283
 284         /* allocate instance-specific interface IDs */
 285         status = usb_interface_id(c, f);
 286         if (status < 0)
 287                 goto fail;
 288         eem->ctrl_id = status;
 289         eem_intf.bInterfaceNumber = status;
 290
 291         status = -ENODEV;
 292
 293         /* allocate instance-specific endpoints */
 294         ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_in_desc);
 295         if (!ep)
 296                 goto fail;
 297         eem->port.in_ep = ep;
 298
 299         ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_out_desc);
 300         if (!ep)
 301                 goto fail;
 302         eem->port.out_ep = ep;
 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, 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         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 329
 330         return status;
 331 }
 332
 333 static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req)
 334 {
 335         struct in_context *ctx = req->context;
 336
 337         dev_kfree_skb_any(ctx->skb);
 338         kfree(req->buf);
 339         usb_ep_free_request(ctx->ep, req);
 340         kfree(ctx);
 341 }
 342
 343 /*
 344  * Add the EEM header and ethernet checksum.
 345  * We currently do not attempt to put multiple ethernet frames
 346  * into a single USB transfer
 347  */
 348 static struct sk_buff *eem_wrap(struct gether *port, struct sk_buff *skb)
 349 {
 350         struct sk_buff  *skb2 = NULL;
 351         struct usb_ep   *in = port->in_ep;
 352         int             headroom, tailroom, padlen = 0;
 353         u16             len;
 354
 355         if (!skb)
 356                 return NULL;
 357
 358         len = skb->len;
 359         headroom = skb_headroom(skb);
 360         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) && !skb_cloned(skb))
 370                 goto done;
 371
 372         skb2 = skb_copy_expand(skb, EEM_HLEN, ETH_FCS_LEN + padlen, GFP_ATOMIC);
 373         dev_kfree_skb_any(skb);
 374         skb = skb2;
 375         if (!skb)
 376                 return skb;
 377
 378 done:
 379         /* use the "no CRC" option */
 380         put_unaligned_be32(0xdeadbeef, skb_put(skb, 4));
 381
 382         /* EEM packet header format:
 383          * b0..13:      length of ethernet frame
 384          * b14:         bmCRC (0 == sentinel CRC)
 385          * b15:         bmType (0 == data)
 386          */
 387         len = skb->len;
 388         put_unaligned_le16(len & 0x3FFF, skb_push(skb, 2));
 389
 390         /* add a zero-length EEM packet, if needed */
 391         if (padlen)
 392                 put_unaligned_le16(0, skb_put(skb, 2));
 393
 394         return skb;
 395 }
 396
 397 /*
 398  * Remove the EEM header.  Note that there can be many EEM packets in a single
 399  * USB transfer, so we need to break them out and handle them independently.
 400  */
 401 static int eem_unwrap(struct gether *port,
 402                         struct sk_buff *skb,
 403                         struct sk_buff_head *list)
 404 {
 405         struct usb_composite_dev        *cdev = port->func.config->cdev;
 406         int                             status = 0;
 407
 408         do {
 409                 struct sk_buff  *skb2;
 410                 u16             header;
 411                 u16             len = 0;
 412
 413                 if (skb->len < EEM_HLEN) {
 414                         status = -EINVAL;
 415                         DBG(cdev, "invalid EEM header\n");
 416                         goto error;
 417                 }
 418
 419                 /* remove the EEM header */
 420                 header = get_unaligned_le16(skb->data);
 421                 skb_pull(skb, EEM_HLEN);
 422
 423                 /* EEM packet header format:
 424                  * b0..14:      EEM type dependent (data or command)
 425                  * b15:         bmType (0 == data, 1 == command)
 426                  */
 427                 if (header & BIT(15)) {
 428                         struct usb_request      *req;
 429                         struct in_context       *ctx;
 430                         struct usb_ep           *ep;
 431                         u16                     bmEEMCmd;
 432
 433                         /* EEM command packet format:
 434                          * b0..10:      bmEEMCmdParam
 435                          * b11..13:     bmEEMCmd
 436                          * b14:         reserved (must be zero)
 437                          * b15:         bmType (1 == command)
 438                          */
 439                         if (header & BIT(14))
 440                                 continue;
 441
 442                         bmEEMCmd = (header >> 11) & 0x7;
 443                         switch (bmEEMCmd) {
 444                         case 0: /* echo */
 445                                 len = header & 0x7FF;
 446                                 if (skb->len < len) {
 447                                         status = -EOVERFLOW;
 448                                         goto error;
 449                                 }
 450
 451                                 skb2 = skb_clone(skb, GFP_ATOMIC);
 452                                 if (unlikely(!skb2)) {
 453                                         DBG(cdev, "EEM echo response error\n");
 454                                         goto next;
 455                                 }
 456                                 skb_trim(skb2, len);
 457                                 put_unaligned_le16(BIT(15) | BIT(11) | len,
 458                                                         skb_push(skb2, 2));
 459
 460                                 ep = port->in_ep;
 461                                 req = usb_ep_alloc_request(ep, GFP_ATOMIC);
 462                                 if (!req) {
 463                                         dev_kfree_skb_any(skb2);
 464                                         goto next;
 465                                 }
 466
 467                                 req->buf = kmalloc(skb2->len, GFP_KERNEL);
 468                                 if (!req->buf) {
 469                                         usb_ep_free_request(ep, req);
 470                                         dev_kfree_skb_any(skb2);
 471                                         goto next;
 472                                 }
 473
 474                                 ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
 475                                 if (!ctx) {
 476                                         kfree(req->buf);
 477                                         usb_ep_free_request(ep, req);
 478                                         dev_kfree_skb_any(skb2);
 479                                         goto next;
 480                                 }
 481                                 ctx->skb = skb2;
 482                                 ctx->ep = ep;
 483
 484                                 skb_copy_bits(skb2, 0, req->buf, skb2->len);
 485                                 req->length = skb2->len;
 486                                 req->complete = eem_cmd_complete;
 487                                 req->zero = 1;
 488                                 req->context = ctx;
 489                                 if (usb_ep_queue(port->in_ep, req, GFP_ATOMIC))
 490                                         DBG(cdev, "echo response queue fail\n");
 491                                 break;
 492
 493                         case 1:  /* echo response */
 494                         case 2:  /* suspend hint */
 495                         case 3:  /* response hint */
 496                         case 4:  /* response complete hint */
 497                         case 5:  /* tickle */
 498                         default: /* reserved */
 499                                 continue;
 500                         }
 501                 } else {
 502                         u32             crc, crc2;
 503                         struct sk_buff  *skb3;
 504
 505                         /* check for zero-length EEM packet */
 506                         if (header == 0)
 507                                 continue;
 508
 509                         /* EEM data packet format:
 510                          * b0..13:      length of ethernet frame
 511                          * b14:         bmCRC (0 == sentinel, 1 == calculated)
 512                          * b15:         bmType (0 == data)
 513                          */
 514                         len = header & 0x3FFF;
 515                         if ((skb->len < len)
 516                                         || (len < (ETH_HLEN + ETH_FCS_LEN))) {
 517                                 status = -EINVAL;
 518                                 goto error;
 519                         }
 520
 521                         /* validate CRC */
 522                         if (header & BIT(14)) {
 523                                 crc = get_unaligned_le32(skb->data + len
 524                                                         - ETH_FCS_LEN);
 525                                 crc2 = ~crc32_le(~0,
 526                                                 skb->data, len - ETH_FCS_LEN);
 527                         } else {
 528                                 crc = get_unaligned_be32(skb->data + len
 529                                                         - ETH_FCS_LEN);
 530                                 crc2 = 0xdeadbeef;
 531                         }
 532                         if (crc != crc2) {
 533                                 DBG(cdev, "invalid EEM CRC\n");
 534                                 goto next;
 535                         }
 536
 537                         skb2 = skb_clone(skb, GFP_ATOMIC);
 538                         if (unlikely(!skb2)) {
 539                                 DBG(cdev, "unable to unframe EEM packet\n");
 540                                 goto next;
 541                         }
 542                         skb_trim(skb2, len - ETH_FCS_LEN);
 543
 544                         skb3 = skb_copy_expand(skb2,
 545                                                 NET_IP_ALIGN,
 546                                                 0,
 547                                                 GFP_ATOMIC);
 548                         if (unlikely(!skb3)) {
 549                                 DBG(cdev, "unable to realign EEM packet\n");
 550                                 dev_kfree_skb_any(skb2);
 551                                 goto next;
 552                         }
 553                         dev_kfree_skb_any(skb2);
 554                         skb_queue_tail(list, skb3);
 555                 }
 556 next:
 557                 skb_pull(skb, len);
 558         } while (skb->len);
 559
 560 error:
 561         dev_kfree_skb_any(skb);
 562         return status;
 563 }
 564
 565 static inline struct f_eem_opts *to_f_eem_opts(struct config_item *item)
 566 {
 567         return container_of(to_config_group(item), struct f_eem_opts,
 568                             func_inst.group);
 569 }
 570
 571 /* f_eem_item_ops */
 572 USB_ETHERNET_CONFIGFS_ITEM(eem);
 573
 574 /* f_eem_opts_dev_addr */
 575 USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(eem);
 576
 577 /* f_eem_opts_host_addr */
 578 USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(eem);
 579
 580 /* f_eem_opts_qmult */
 581 USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(eem);
 582
 583 /* f_eem_opts_ifname */
 584 USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(eem);
 585
 586 static struct configfs_attribute *eem_attrs[] = {
 587         &eem_opts_attr_dev_addr,
 588         &eem_opts_attr_host_addr,
 589         &eem_opts_attr_qmult,
 590         &eem_opts_attr_ifname,
 591         NULL,
 592 };
 593
 594 static struct config_item_type eem_func_type = {
 595         .ct_item_ops    = &eem_item_ops,
 596         .ct_attrs       = eem_attrs,
 597         .ct_owner       = THIS_MODULE,
 598 };
 599
 600 static void eem_free_inst(struct usb_function_instance *f)
 601 {
 602         struct f_eem_opts *opts;
 603
 604         opts = container_of(f, struct f_eem_opts, func_inst);
 605         if (opts->bound)
 606                 gether_cleanup(netdev_priv(opts->net));
 607         else
 608                 free_netdev(opts->net);
 609         kfree(opts);
 610 }
 611
 612 static struct usb_function_instance *eem_alloc_inst(void)
 613 {
 614         struct f_eem_opts *opts;
 615
 616         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 617         if (!opts)
 618                 return ERR_PTR(-ENOMEM);
 619         mutex_init(&opts->lock);
 620         opts->func_inst.free_func_inst = eem_free_inst;
 621         opts->net = gether_setup_default();
 622         if (IS_ERR(opts->net)) {
 623                 struct net_device *net = opts->net;
 624                 kfree(opts);
 625                 return ERR_CAST(net);
 626         }
 627
 628         config_group_init_type_name(&opts->func_inst.group, "", &eem_func_type);
 629
 630         return &opts->func_inst;
 631 }
 632
 633 static void eem_free(struct usb_function *f)
 634 {
 635         struct f_eem *eem;
 636         struct f_eem_opts *opts;
 637
 638         eem = func_to_eem(f);
 639         opts = container_of(f->fi, struct f_eem_opts, func_inst);
 640         kfree(eem);
 641         mutex_lock(&opts->lock);
 642         opts->refcnt--;
 643         mutex_unlock(&opts->lock);
 644 }
 645
 646 static void eem_unbind(struct usb_configuration *c, struct usb_function *f)
 647 {
 648         DBG(c->cdev, "eem unbind\n");
 649
 650         usb_free_all_descriptors(f);
 651 }
 652
 653 static struct usb_function *eem_alloc(struct usb_function_instance *fi)
 654 {
 655         struct f_eem    *eem;
 656         struct f_eem_opts *opts;
 657
 658         /* allocate and initialize one new instance */
 659         eem = kzalloc(sizeof(*eem), GFP_KERNEL);
 660         if (!eem)
 661                 return ERR_PTR(-ENOMEM);
 662
 663         opts = container_of(fi, struct f_eem_opts, func_inst);
 664         mutex_lock(&opts->lock);
 665         opts->refcnt++;
 666
 667         eem->port.ioport = netdev_priv(opts->net);
 668         mutex_unlock(&opts->lock);
 669         eem->port.cdc_filter = DEFAULT_FILTER;
 670
 671         eem->port.func.name = "cdc_eem";
 672         /* descriptors are per-instance copies */
 673         eem->port.func.bind = eem_bind;
 674         eem->port.func.unbind = eem_unbind;
 675         eem->port.func.set_alt = eem_set_alt;
 676         eem->port.func.setup = eem_setup;
 677         eem->port.func.disable = eem_disable;
 678         eem->port.func.free_func = eem_free;
 679         eem->port.wrap = eem_wrap;
 680         eem->port.unwrap = eem_unwrap;
 681         eem->port.header_len = EEM_HLEN;
 682
 683         return &eem->port.func;
 684 }
 685
 686 DECLARE_USB_FUNCTION_INIT(eem, eem_alloc_inst, eem_alloc);
 687 MODULE_LICENSE("GPL");
 688 MODULE_AUTHOR("David Brownell");