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