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/device.h>
  16 #include <linux/etherdevice.h>
  17 #include <linux/crc32.h>
  18 #include <linux/slab.h>
  19
  20 #include "u_ether.h"
  21
  22 #define EEM_HLEN 2
  23
  24 /*
  25  * This function is a "CDC Ethernet Emulation Model" (CDC EEM)
  26  * Ethernet link.
  27  */
  28
  29 struct f_eem {
  30         struct gether                   port;
  31         u8                              ctrl_id;
  32 };
  33
  34 static inline struct f_eem *func_to_eem(struct usb_function *f)
  35 {
  36         return container_of(f, struct f_eem, port.func);
  37 }
  38
  39 /*-------------------------------------------------------------------------*/
  40
  41 /* interface descriptor: */
  42
  43 static struct usb_interface_descriptor eem_intf __initdata = {
  44         .bLength =              sizeof eem_intf,
  45         .bDescriptorType =      USB_DT_INTERFACE,
  46
  47         /* .bInterfaceNumber = DYNAMIC */
  48         .bNumEndpoints =        2,
  49         .bInterfaceClass =      USB_CLASS_COMM,
  50         .bInterfaceSubClass =   USB_CDC_SUBCLASS_EEM,
  51         .bInterfaceProtocol =   USB_CDC_PROTO_EEM,
  52         /* .iInterface = DYNAMIC */
  53 };
  54
  55 /* full speed support: */
  56
  57 static struct usb_endpoint_descriptor eem_fs_in_desc __initdata = {
  58         .bLength =              USB_DT_ENDPOINT_SIZE,
  59         .bDescriptorType =      USB_DT_ENDPOINT,
  60
  61         .bEndpointAddress =     USB_DIR_IN,
  62         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  63 };
  64
  65 static struct usb_endpoint_descriptor eem_fs_out_desc __initdata = {
  66         .bLength =              USB_DT_ENDPOINT_SIZE,
  67         .bDescriptorType =      USB_DT_ENDPOINT,
  68
  69         .bEndpointAddress =     USB_DIR_OUT,
  70         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  71 };
  72
  73 static struct usb_descriptor_header *eem_fs_function[] __initdata = {
  74         /* CDC EEM control descriptors */
  75         (struct usb_descriptor_header *) &eem_intf,
  76         (struct usb_descriptor_header *) &eem_fs_in_desc,
  77         (struct usb_descriptor_header *) &eem_fs_out_desc,
  78         NULL,
  79 };
  80
  81 /* high speed support: */
  82
  83 static struct usb_endpoint_descriptor eem_hs_in_desc __initdata = {
  84         .bLength =              USB_DT_ENDPOINT_SIZE,
  85         .bDescriptorType =      USB_DT_ENDPOINT,
  86
  87         .bEndpointAddress =     USB_DIR_IN,
  88         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  89         .wMaxPacketSize =       cpu_to_le16(512),
  90 };
  91
  92 static struct usb_endpoint_descriptor eem_hs_out_desc __initdata = {
  93         .bLength =              USB_DT_ENDPOINT_SIZE,
  94         .bDescriptorType =      USB_DT_ENDPOINT,
  95
  96         .bEndpointAddress =     USB_DIR_OUT,
  97         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  98         .wMaxPacketSize =       cpu_to_le16(512),
  99 };
 100
 101 static struct usb_descriptor_header *eem_hs_function[] __initdata = {
 102         /* CDC EEM control descriptors */
 103         (struct usb_descriptor_header *) &eem_intf,
 104         (struct usb_descriptor_header *) &eem_hs_in_desc,
 105         (struct usb_descriptor_header *) &eem_hs_out_desc,
 106         NULL,
 107 };
 108
 109 /* super speed support: */
 110
 111 static struct usb_endpoint_descriptor eem_ss_in_desc __initdata = {
 112         .bLength =              USB_DT_ENDPOINT_SIZE,
 113         .bDescriptorType =      USB_DT_ENDPOINT,
 114
 115         .bEndpointAddress =     USB_DIR_IN,
 116         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 117         .wMaxPacketSize =       cpu_to_le16(1024),
 118 };
 119
 120 static struct usb_endpoint_descriptor eem_ss_out_desc __initdata = {
 121         .bLength =              USB_DT_ENDPOINT_SIZE,
 122         .bDescriptorType =      USB_DT_ENDPOINT,
 123
 124         .bEndpointAddress =     USB_DIR_OUT,
 125         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 126         .wMaxPacketSize =       cpu_to_le16(1024),
 127 };
 128
 129 static struct usb_ss_ep_comp_descriptor eem_ss_bulk_comp_desc __initdata = {
 130         .bLength =              sizeof eem_ss_bulk_comp_desc,
 131         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 132
 133         /* the following 2 values can be tweaked if necessary */
 134         /* .bMaxBurst =         0, */
 135         /* .bmAttributes =      0, */
 136 };
 137
 138 static struct usb_descriptor_header *eem_ss_function[] __initdata = {
 139         /* CDC EEM control descriptors */
 140         (struct usb_descriptor_header *) &eem_intf,
 141         (struct usb_descriptor_header *) &eem_ss_in_desc,
 142         (struct usb_descriptor_header *) &eem_ss_bulk_comp_desc,
 143         (struct usb_descriptor_header *) &eem_ss_out_desc,
 144         (struct usb_descriptor_header *) &eem_ss_bulk_comp_desc,
 145         NULL,
 146 };
 147
 148 /* string descriptors: */
 149
 150 static struct usb_string eem_string_defs[] = {
 151         [0].s = "CDC Ethernet Emulation Model (EEM)",
 152         {  } /* end of list */
 153 };
 154
 155 static struct usb_gadget_strings eem_string_table = {
 156         .language =             0x0409, /* en-us */
 157         .strings =              eem_string_defs,
 158 };
 159
 160 static struct usb_gadget_strings *eem_strings[] = {
 161         &eem_string_table,
 162         NULL,
 163 };
 164
 165 /*-------------------------------------------------------------------------*/
 166
 167 static int eem_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 168 {
 169         struct usb_composite_dev *cdev = f->config->cdev;
 170         int                     value = -EOPNOTSUPP;
 171         u16                     w_index = le16_to_cpu(ctrl->wIndex);
 172         u16                     w_value = le16_to_cpu(ctrl->wValue);
 173         u16                     w_length = le16_to_cpu(ctrl->wLength);
 174
 175         DBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
 176                 ctrl->bRequestType, ctrl->bRequest,
 177                 w_value, w_index, w_length);
 178
 179         /* device either stalls (value < 0) or reports success */
 180         return value;
 181 }
 182
 183
 184 static int eem_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 185 {
 186         struct f_eem            *eem = func_to_eem(f);
 187         struct usb_composite_dev *cdev = f->config->cdev;
 188         struct net_device       *net;
 189
 190         /* we know alt == 0, so this is an activation or a reset */
 191         if (alt != 0)
 192                 goto fail;
 193
 194         if (intf == eem->ctrl_id) {
 195
 196                 if (eem->port.in_ep->driver_data) {
 197                         DBG(cdev, "reset eem\n");
 198                         gether_disconnect(&eem->port);
 199                 }
 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->driver_data)
 238                 gether_disconnect(&eem->port);
 239 }
 240
 241 /*-------------------------------------------------------------------------*/
 242
 243 /* EEM function driver setup/binding */
 244
 245 static int __init
 246 eem_bind(struct usb_configuration *c, struct usb_function *f)
 247 {
 248         struct usb_composite_dev *cdev = c->cdev;
 249         struct f_eem            *eem = func_to_eem(f);
 250         int                     status;
 251         struct usb_ep           *ep;
 252
 253         /* allocate instance-specific interface IDs */
 254         status = usb_interface_id(c, f);
 255         if (status < 0)
 256                 goto fail;
 257         eem->ctrl_id = status;
 258         eem_intf.bInterfaceNumber = status;
 259
 260         status = -ENODEV;
 261
 262         /* allocate instance-specific endpoints */
 263         ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_in_desc);
 264         if (!ep)
 265                 goto fail;
 266         eem->port.in_ep = ep;
 267         ep->driver_data = cdev; /* claim */
 268
 269         ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_out_desc);
 270         if (!ep)
 271                 goto fail;
 272         eem->port.out_ep = ep;
 273         ep->driver_data = cdev; /* claim */
 274
 275         status = -ENOMEM;
 276
 277         /* copy descriptors, and track endpoint copies */
 278         f->descriptors = usb_copy_descriptors(eem_fs_function);
 279         if (!f->descriptors)
 280                 goto fail;
 281
 282         /* support all relevant hardware speeds... we expect that when
 283          * hardware is dual speed, all bulk-capable endpoints work at
 284          * both speeds
 285          */
 286         if (gadget_is_dualspeed(c->cdev->gadget)) {
 287                 eem_hs_in_desc.bEndpointAddress =
 288                                 eem_fs_in_desc.bEndpointAddress;
 289                 eem_hs_out_desc.bEndpointAddress =
 290                                 eem_fs_out_desc.bEndpointAddress;
 291
 292                 /* copy descriptors, and track endpoint copies */
 293                 f->hs_descriptors = usb_copy_descriptors(eem_hs_function);
 294                 if (!f->hs_descriptors)
 295                         goto fail;
 296         }
 297
 298         if (gadget_is_superspeed(c->cdev->gadget)) {
 299                 eem_ss_in_desc.bEndpointAddress =
 300                                 eem_fs_in_desc.bEndpointAddress;
 301                 eem_ss_out_desc.bEndpointAddress =
 302                                 eem_fs_out_desc.bEndpointAddress;
 303
 304                 /* copy descriptors, and track endpoint copies */
 305                 f->ss_descriptors = usb_copy_descriptors(eem_ss_function);
 306                 if (!f->ss_descriptors)
 307                         goto fail;
 308         }
 309
 310         DBG(cdev, "CDC Ethernet (EEM): %s speed IN/%s OUT/%s\n",
 311                         gadget_is_superspeed(c->cdev->gadget) ? "super" :
 312                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 313                         eem->port.in_ep->name, eem->port.out_ep->name);
 314         return 0;
 315
 316 fail:
 317         if (f->descriptors)
 318                 usb_free_descriptors(f->descriptors);
 319         if (f->hs_descriptors)
 320                 usb_free_descriptors(f->hs_descriptors);
 321
 322         /* we might as well release our claims on endpoints */
 323         if (eem->port.out_ep->desc)
 324                 eem->port.out_ep->driver_data = NULL;
 325         if (eem->port.in_ep->desc)
 326                 eem->port.in_ep->driver_data = NULL;
 327
 328         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 329
 330         return status;
 331 }
 332
 333 static void
 334 eem_unbind(struct usb_configuration *c, struct usb_function *f)
 335 {
 336         struct f_eem    *eem = func_to_eem(f);
 337
 338         DBG(c->cdev, "eem unbind\n");
 339
 340         if (gadget_is_superspeed(c->cdev->gadget))
 341                 usb_free_descriptors(f->ss_descriptors);
 342         if (gadget_is_dualspeed(c->cdev->gadget))
 343                 usb_free_descriptors(f->hs_descriptors);
 344         usb_free_descriptors(f->descriptors);
 345         kfree(eem);
 346 }
 347
 348 static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req)
 349 {
 350         struct sk_buff *skb = (struct sk_buff *)req->context;
 351
 352         dev_kfree_skb_any(skb);
 353 }
 354
 355 /*
 356  * Add the EEM header and ethernet checksum.
 357  * We currently do not attempt to put multiple ethernet frames
 358  * into a single USB transfer
 359  */
 360 static struct sk_buff *eem_wrap(struct gether *port, struct sk_buff *skb)
 361 {
 362         struct sk_buff  *skb2 = NULL;
 363         struct usb_ep   *in = port->in_ep;
 364         int             padlen = 0;
 365         u16             len = skb->len;
 366
 367         if (!skb_cloned(skb)) {
 368                 int headroom = skb_headroom(skb);
 369                 int tailroom = skb_tailroom(skb);
 370
 371                 /* When (len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) is 0,
 372                  * stick two bytes of zero-length EEM packet on the end.
 373                  */
 374                 if (((len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) == 0)
 375                         padlen += 2;
 376
 377                 if ((tailroom >= (ETH_FCS_LEN + padlen)) &&
 378                                 (headroom >= EEM_HLEN))
 379                         goto done;
 380         }
 381
 382         skb2 = skb_copy_expand(skb, EEM_HLEN, ETH_FCS_LEN + padlen, GFP_ATOMIC);
 383         dev_kfree_skb_any(skb);
 384         skb = skb2;
 385         if (!skb)
 386                 return skb;
 387
 388 done:
 389         /* use the "no CRC" option */
 390         put_unaligned_be32(0xdeadbeef, skb_put(skb, 4));
 391
 392         /* EEM packet header format:
 393          * b0..13:      length of ethernet frame
 394          * b14:         bmCRC (0 == sentinel CRC)
 395          * b15:         bmType (0 == data)
 396          */
 397         len = skb->len;
 398         put_unaligned_le16(len & 0x3FFF, skb_push(skb, 2));
 399
 400         /* add a zero-length EEM packet, if needed */
 401         if (padlen)
 402                 put_unaligned_le16(0, skb_put(skb, 2));
 403
 404         return skb;
 405 }
 406
 407 /*
 408  * Remove the EEM header.  Note that there can be many EEM packets in a single
 409  * USB transfer, so we need to break them out and handle them independently.
 410  */
 411 static int eem_unwrap(struct gether *port,
 412                         struct sk_buff *skb,
 413                         struct sk_buff_head *list)
 414 {
 415         struct usb_composite_dev        *cdev = port->func.config->cdev;
 416         int                             status = 0;
 417
 418         do {
 419                 struct sk_buff  *skb2;
 420                 u16             header;
 421                 u16             len = 0;
 422
 423                 if (skb->len < EEM_HLEN) {
 424                         status = -EINVAL;
 425                         DBG(cdev, "invalid EEM header\n");
 426                         goto error;
 427                 }
 428
 429                 /* remove the EEM header */
 430                 header = get_unaligned_le16(skb->data);
 431                 skb_pull(skb, EEM_HLEN);
 432
 433                 /* EEM packet header format:
 434                  * b0..14:      EEM type dependent (data or command)
 435                  * b15:         bmType (0 == data, 1 == command)
 436                  */
 437                 if (header & BIT(15)) {
 438                         struct usb_request      *req = cdev->req;
 439                         u16                     bmEEMCmd;
 440
 441                         /* EEM command packet format:
 442                          * b0..10:      bmEEMCmdParam
 443                          * b11..13:     bmEEMCmd
 444                          * b14:         reserved (must be zero)
 445                          * b15:         bmType (1 == command)
 446                          */
 447                         if (header & BIT(14))
 448                                 continue;
 449
 450                         bmEEMCmd = (header >> 11) & 0x7;
 451                         switch (bmEEMCmd) {
 452                         case 0: /* echo */
 453                                 len = header & 0x7FF;
 454                                 if (skb->len < len) {
 455                                         status = -EOVERFLOW;
 456                                         goto error;
 457                                 }
 458
 459                                 skb2 = skb_clone(skb, GFP_ATOMIC);
 460                                 if (unlikely(!skb2)) {
 461                                         DBG(cdev, "EEM echo response error\n");
 462                                         goto next;
 463                                 }
 464                                 skb_trim(skb2, len);
 465                                 put_unaligned_le16(BIT(15) | BIT(11) | len,
 466                                                         skb_push(skb2, 2));
 467                                 skb_copy_bits(skb2, 0, req->buf, skb2->len);
 468                                 req->length = skb2->len;
 469                                 req->complete = eem_cmd_complete;
 470                                 req->zero = 1;
 471                                 req->context = skb2;
 472                                 if (usb_ep_queue(port->in_ep, req, GFP_ATOMIC))
 473                                         DBG(cdev, "echo response queue fail\n");
 474                                 break;
 475
 476                         case 1:  /* echo response */
 477                         case 2:  /* suspend hint */
 478                         case 3:  /* response hint */
 479                         case 4:  /* response complete hint */
 480                         case 5:  /* tickle */
 481                         default: /* reserved */
 482                                 continue;
 483                         }
 484                 } else {
 485                         u32             crc, crc2;
 486                         struct sk_buff  *skb3;
 487
 488                         /* check for zero-length EEM packet */
 489                         if (header == 0)
 490                                 continue;
 491
 492                         /* EEM data packet format:
 493                          * b0..13:      length of ethernet frame
 494                          * b14:         bmCRC (0 == sentinel, 1 == calculated)
 495                          * b15:         bmType (0 == data)
 496                          */
 497                         len = header & 0x3FFF;
 498                         if ((skb->len < len)
 499                                         || (len < (ETH_HLEN + ETH_FCS_LEN))) {
 500                                 status = -EINVAL;
 501                                 goto error;
 502                         }
 503
 504                         /* validate CRC */
 505                         if (header & BIT(14)) {
 506                                 crc = get_unaligned_le32(skb->data + len
 507                                                         - ETH_FCS_LEN);
 508                                 crc2 = ~crc32_le(~0,
 509                                                 skb->data, len - ETH_FCS_LEN);
 510                         } else {
 511                                 crc = get_unaligned_be32(skb->data + len
 512                                                         - ETH_FCS_LEN);
 513                                 crc2 = 0xdeadbeef;
 514                         }
 515                         if (crc != crc2) {
 516                                 DBG(cdev, "invalid EEM CRC\n");
 517                                 goto next;
 518                         }
 519
 520                         skb2 = skb_clone(skb, GFP_ATOMIC);
 521                         if (unlikely(!skb2)) {
 522                                 DBG(cdev, "unable to unframe EEM packet\n");
 523                                 continue;
 524                         }
 525                         skb_trim(skb2, len - ETH_FCS_LEN);
 526
 527                         skb3 = skb_copy_expand(skb2,
 528                                                 NET_IP_ALIGN,
 529                                                 0,
 530                                                 GFP_ATOMIC);
 531                         if (unlikely(!skb3)) {
 532                                 DBG(cdev, "unable to realign EEM packet\n");
 533                                 dev_kfree_skb_any(skb2);
 534                                 continue;
 535                         }
 536                         dev_kfree_skb_any(skb2);
 537                         skb_queue_tail(list, skb3);
 538                 }
 539 next:
 540                 skb_pull(skb, len);
 541         } while (skb->len);
 542
 543 error:
 544         dev_kfree_skb_any(skb);
 545         return status;
 546 }
 547
 548 /**
 549  * eem_bind_config - add CDC Ethernet (EEM) network link to a configuration
 550  * @c: the configuration to support the network link
 551  * Context: single threaded during gadget setup
 552  *
 553  * Returns zero on success, else negative errno.
 554  *
 555  * Caller must have called @gether_setup().  Caller is also responsible
 556  * for calling @gether_cleanup() before module unload.
 557  */
 558 int __init eem_bind_config(struct usb_configuration *c)
 559 {
 560         struct f_eem    *eem;
 561         int             status;
 562
 563         /* maybe allocate device-global string IDs */
 564         if (eem_string_defs[0].id == 0) {
 565
 566                 /* control interface label */
 567                 status = usb_string_id(c->cdev);
 568                 if (status < 0)
 569                         return status;
 570                 eem_string_defs[0].id = status;
 571                 eem_intf.iInterface = status;
 572         }
 573
 574         /* allocate and initialize one new instance */
 575         eem = kzalloc(sizeof *eem, GFP_KERNEL);
 576         if (!eem)
 577                 return -ENOMEM;
 578
 579         eem->port.cdc_filter = DEFAULT_FILTER;
 580
 581         eem->port.func.name = "cdc_eem";
 582         eem->port.func.strings = eem_strings;
 583         /* descriptors are per-instance copies */
 584         eem->port.func.bind = eem_bind;
 585         eem->port.func.unbind = eem_unbind;
 586         eem->port.func.set_alt = eem_set_alt;
 587         eem->port.func.setup = eem_setup;
 588         eem->port.func.disable = eem_disable;
 589         eem->port.wrap = eem_wrap;
 590         eem->port.unwrap = eem_unwrap;
 591         eem->port.header_len = EEM_HLEN;
 592
 593         status = usb_add_function(c, &eem->port.func);
 594         if (status)
 595                 kfree(eem);
 596         return status;
 597 }
 598