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         /* support all relevant hardware speeds... we expect that when
 278          * hardware is dual speed, all bulk-capable endpoints work at
 279          * both speeds
 280          */
 281         eem_hs_in_desc.bEndpointAddress = eem_fs_in_desc.bEndpointAddress;
 282         eem_hs_out_desc.bEndpointAddress = eem_fs_out_desc.bEndpointAddress;
 283
 284         eem_ss_in_desc.bEndpointAddress = eem_fs_in_desc.bEndpointAddress;
 285         eem_ss_out_desc.bEndpointAddress = eem_fs_out_desc.bEndpointAddress;
 286
 287         status = usb_assign_descriptors(f, eem_fs_function, eem_hs_function,
 288                         eem_ss_function);
 289         if (status)
 290                 goto fail;
 291
 292         DBG(cdev, "CDC Ethernet (EEM): %s speed IN/%s OUT/%s\n",
 293                         gadget_is_superspeed(c->cdev->gadget) ? "super" :
 294                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 295                         eem->port.in_ep->name, eem->port.out_ep->name);
 296         return 0;
 297
 298 fail:
 299         usb_free_all_descriptors(f);
 300         if (eem->port.out_ep)
 301                 eem->port.out_ep->driver_data = NULL;
 302         if (eem->port.in_ep)
 303                 eem->port.in_ep->driver_data = NULL;
 304
 305         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 306
 307         return status;
 308 }
 309
 310 static void
 311 eem_unbind(struct usb_configuration *c, struct usb_function *f)
 312 {
 313         struct f_eem    *eem = func_to_eem(f);
 314
 315         DBG(c->cdev, "eem unbind\n");
 316
 317         usb_free_all_descriptors(f);
 318         kfree(eem);
 319 }
 320
 321 static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req)
 322 {
 323         struct sk_buff *skb = (struct sk_buff *)req->context;
 324
 325         dev_kfree_skb_any(skb);
 326 }
 327
 328 /*
 329  * Add the EEM header and ethernet checksum.
 330  * We currently do not attempt to put multiple ethernet frames
 331  * into a single USB transfer
 332  */
 333 static struct sk_buff *eem_wrap(struct gether *port, struct sk_buff *skb)
 334 {
 335         struct sk_buff  *skb2 = NULL;
 336         struct usb_ep   *in = port->in_ep;
 337         int             padlen = 0;
 338         u16             len = skb->len;
 339
 340         if (!skb_cloned(skb)) {
 341                 int headroom = skb_headroom(skb);
 342                 int tailroom = skb_tailroom(skb);
 343
 344                 /* When (len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) is 0,
 345                  * stick two bytes of zero-length EEM packet on the end.
 346                  */
 347                 if (((len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) == 0)
 348                         padlen += 2;
 349
 350                 if ((tailroom >= (ETH_FCS_LEN + padlen)) &&
 351                                 (headroom >= EEM_HLEN))
 352                         goto done;
 353         }
 354
 355         skb2 = skb_copy_expand(skb, EEM_HLEN, ETH_FCS_LEN + padlen, GFP_ATOMIC);
 356         dev_kfree_skb_any(skb);
 357         skb = skb2;
 358         if (!skb)
 359                 return skb;
 360
 361 done:
 362         /* use the "no CRC" option */
 363         put_unaligned_be32(0xdeadbeef, skb_put(skb, 4));
 364
 365         /* EEM packet header format:
 366          * b0..13:      length of ethernet frame
 367          * b14:         bmCRC (0 == sentinel CRC)
 368          * b15:         bmType (0 == data)
 369          */
 370         len = skb->len;
 371         put_unaligned_le16(len & 0x3FFF, skb_push(skb, 2));
 372
 373         /* add a zero-length EEM packet, if needed */
 374         if (padlen)
 375                 put_unaligned_le16(0, skb_put(skb, 2));
 376
 377         return skb;
 378 }
 379
 380 /*
 381  * Remove the EEM header.  Note that there can be many EEM packets in a single
 382  * USB transfer, so we need to break them out and handle them independently.
 383  */
 384 static int eem_unwrap(struct gether *port,
 385                         struct sk_buff *skb,
 386                         struct sk_buff_head *list)
 387 {
 388         struct usb_composite_dev        *cdev = port->func.config->cdev;
 389         int                             status = 0;
 390
 391         do {
 392                 struct sk_buff  *skb2;
 393                 u16             header;
 394                 u16             len = 0;
 395
 396                 if (skb->len < EEM_HLEN) {
 397                         status = -EINVAL;
 398                         DBG(cdev, "invalid EEM header\n");
 399                         goto error;
 400                 }
 401
 402                 /* remove the EEM header */
 403                 header = get_unaligned_le16(skb->data);
 404                 skb_pull(skb, EEM_HLEN);
 405
 406                 /* EEM packet header format:
 407                  * b0..14:      EEM type dependent (data or command)
 408                  * b15:         bmType (0 == data, 1 == command)
 409                  */
 410                 if (header & BIT(15)) {
 411                         struct usb_request      *req = cdev->req;
 412                         u16                     bmEEMCmd;
 413
 414                         /* EEM command packet format:
 415                          * b0..10:      bmEEMCmdParam
 416                          * b11..13:     bmEEMCmd
 417                          * b14:         reserved (must be zero)
 418                          * b15:         bmType (1 == command)
 419                          */
 420                         if (header & BIT(14))
 421                                 continue;
 422
 423                         bmEEMCmd = (header >> 11) & 0x7;
 424                         switch (bmEEMCmd) {
 425                         case 0: /* echo */
 426                                 len = header & 0x7FF;
 427                                 if (skb->len < len) {
 428                                         status = -EOVERFLOW;
 429                                         goto error;
 430                                 }
 431
 432                                 skb2 = skb_clone(skb, GFP_ATOMIC);
 433                                 if (unlikely(!skb2)) {
 434                                         DBG(cdev, "EEM echo response error\n");
 435                                         goto next;
 436                                 }
 437                                 skb_trim(skb2, len);
 438                                 put_unaligned_le16(BIT(15) | BIT(11) | len,
 439                                                         skb_push(skb2, 2));
 440                                 skb_copy_bits(skb2, 0, req->buf, skb2->len);
 441                                 req->length = skb2->len;
 442                                 req->complete = eem_cmd_complete;
 443                                 req->zero = 1;
 444                                 req->context = skb2;
 445                                 if (usb_ep_queue(port->in_ep, req, GFP_ATOMIC))
 446                                         DBG(cdev, "echo response queue fail\n");
 447                                 break;
 448
 449                         case 1:  /* echo response */
 450                         case 2:  /* suspend hint */
 451                         case 3:  /* response hint */
 452                         case 4:  /* response complete hint */
 453                         case 5:  /* tickle */
 454                         default: /* reserved */
 455                                 continue;
 456                         }
 457                 } else {
 458                         u32             crc, crc2;
 459                         struct sk_buff  *skb3;
 460
 461                         /* check for zero-length EEM packet */
 462                         if (header == 0)
 463                                 continue;
 464
 465                         /* EEM data packet format:
 466                          * b0..13:      length of ethernet frame
 467                          * b14:         bmCRC (0 == sentinel, 1 == calculated)
 468                          * b15:         bmType (0 == data)
 469                          */
 470                         len = header & 0x3FFF;
 471                         if ((skb->len < len)
 472                                         || (len < (ETH_HLEN + ETH_FCS_LEN))) {
 473                                 status = -EINVAL;
 474                                 goto error;
 475                         }
 476
 477                         /* validate CRC */
 478                         if (header & BIT(14)) {
 479                                 crc = get_unaligned_le32(skb->data + len
 480                                                         - ETH_FCS_LEN);
 481                                 crc2 = ~crc32_le(~0,
 482                                                 skb->data, len - ETH_FCS_LEN);
 483                         } else {
 484                                 crc = get_unaligned_be32(skb->data + len
 485                                                         - ETH_FCS_LEN);
 486                                 crc2 = 0xdeadbeef;
 487                         }
 488                         if (crc != crc2) {
 489                                 DBG(cdev, "invalid EEM CRC\n");
 490                                 goto next;
 491                         }
 492
 493                         skb2 = skb_clone(skb, GFP_ATOMIC);
 494                         if (unlikely(!skb2)) {
 495                                 DBG(cdev, "unable to unframe EEM packet\n");
 496                                 continue;
 497                         }
 498                         skb_trim(skb2, len - ETH_FCS_LEN);
 499
 500                         skb3 = skb_copy_expand(skb2,
 501                                                 NET_IP_ALIGN,
 502                                                 0,
 503                                                 GFP_ATOMIC);
 504                         if (unlikely(!skb3)) {
 505                                 DBG(cdev, "unable to realign EEM packet\n");
 506                                 dev_kfree_skb_any(skb2);
 507                                 continue;
 508                         }
 509                         dev_kfree_skb_any(skb2);
 510                         skb_queue_tail(list, skb3);
 511                 }
 512 next:
 513                 skb_pull(skb, len);
 514         } while (skb->len);
 515
 516 error:
 517         dev_kfree_skb_any(skb);
 518         return status;
 519 }
 520
 521 /**
 522  * eem_bind_config - add CDC Ethernet (EEM) network link to a configuration
 523  * @c: the configuration to support the network link
 524  * Context: single threaded during gadget setup
 525  *
 526  * Returns zero on success, else negative errno.
 527  *
 528  * Caller must have called @gether_setup().  Caller is also responsible
 529  * for calling @gether_cleanup() before module unload.
 530  */
 531 int __init eem_bind_config(struct usb_configuration *c)
 532 {
 533         struct f_eem    *eem;
 534         int             status;
 535
 536         /* maybe allocate device-global string IDs */
 537         if (eem_string_defs[0].id == 0) {
 538
 539                 /* control interface label */
 540                 status = usb_string_id(c->cdev);
 541                 if (status < 0)
 542                         return status;
 543                 eem_string_defs[0].id = status;
 544                 eem_intf.iInterface = status;
 545         }
 546
 547         /* allocate and initialize one new instance */
 548         eem = kzalloc(sizeof *eem, GFP_KERNEL);
 549         if (!eem)
 550                 return -ENOMEM;
 551
 552         eem->port.cdc_filter = DEFAULT_FILTER;
 553
 554         eem->port.func.name = "cdc_eem";
 555         eem->port.func.strings = eem_strings;
 556         /* descriptors are per-instance copies */
 557         eem->port.func.bind = eem_bind;
 558         eem->port.func.unbind = eem_unbind;
 559         eem->port.func.set_alt = eem_set_alt;
 560         eem->port.func.setup = eem_setup;
 561         eem->port.func.disable = eem_disable;
 562         eem->port.wrap = eem_wrap;
 563         eem->port.unwrap = eem_unwrap;
 564         eem->port.header_len = EEM_HLEN;
 565
 566         status = usb_add_function(c, &eem->port.func);
 567         if (status)
 568                 kfree(eem);
 569         return status;
 570 }
 571