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  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 #include <linux/kernel.h>
  24 #include <linux/device.h>
  25 #include <linux/etherdevice.h>
  26 #include <linux/crc32.h>
  27 #include <linux/slab.h>
  28
  29 #include "u_ether.h"
  30
  31 #define EEM_HLEN 2
  32
  33 /*
  34  * This function is a "CDC Ethernet Emulation Model" (CDC EEM)
  35  * Ethernet link.
  36  */
  37
  38 struct eem_ep_descs {
  39         struct usb_endpoint_descriptor  *in;
  40         struct usb_endpoint_descriptor  *out;
  41 };
  42
  43 struct f_eem {
  44         struct gether                   port;
  45         u8                              ctrl_id;
  46
  47         struct eem_ep_descs             fs;
  48         struct eem_ep_descs             hs;
  49 };
  50
  51 static inline struct f_eem *func_to_eem(struct usb_function *f)
  52 {
  53         return container_of(f, struct f_eem, port.func);
  54 }
  55
  56 /*-------------------------------------------------------------------------*/
  57
  58 /* interface descriptor: */
  59
  60 static struct usb_interface_descriptor eem_intf __initdata = {
  61         .bLength =              sizeof eem_intf,
  62         .bDescriptorType =      USB_DT_INTERFACE,
  63
  64         /* .bInterfaceNumber = DYNAMIC */
  65         .bNumEndpoints =        2,
  66         .bInterfaceClass =      USB_CLASS_COMM,
  67         .bInterfaceSubClass =   USB_CDC_SUBCLASS_EEM,
  68         .bInterfaceProtocol =   USB_CDC_PROTO_EEM,
  69         /* .iInterface = DYNAMIC */
  70 };
  71
  72 /* full speed support: */
  73
  74 static struct usb_endpoint_descriptor eem_fs_in_desc __initdata = {
  75         .bLength =              USB_DT_ENDPOINT_SIZE,
  76         .bDescriptorType =      USB_DT_ENDPOINT,
  77
  78         .bEndpointAddress =     USB_DIR_IN,
  79         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  80 };
  81
  82 static struct usb_endpoint_descriptor eem_fs_out_desc __initdata = {
  83         .bLength =              USB_DT_ENDPOINT_SIZE,
  84         .bDescriptorType =      USB_DT_ENDPOINT,
  85
  86         .bEndpointAddress =     USB_DIR_OUT,
  87         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  88 };
  89
  90 static struct usb_descriptor_header *eem_fs_function[] __initdata = {
  91         /* CDC EEM control descriptors */
  92         (struct usb_descriptor_header *) &eem_intf,
  93         (struct usb_descriptor_header *) &eem_fs_in_desc,
  94         (struct usb_descriptor_header *) &eem_fs_out_desc,
  95         NULL,
  96 };
  97
  98 /* high speed support: */
  99
 100 static struct usb_endpoint_descriptor eem_hs_in_desc __initdata = {
 101         .bLength =              USB_DT_ENDPOINT_SIZE,
 102         .bDescriptorType =      USB_DT_ENDPOINT,
 103
 104         .bEndpointAddress =     USB_DIR_IN,
 105         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 106         .wMaxPacketSize =       cpu_to_le16(512),
 107 };
 108
 109 static struct usb_endpoint_descriptor eem_hs_out_desc __initdata = {
 110         .bLength =              USB_DT_ENDPOINT_SIZE,
 111         .bDescriptorType =      USB_DT_ENDPOINT,
 112
 113         .bEndpointAddress =     USB_DIR_OUT,
 114         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 115         .wMaxPacketSize =       cpu_to_le16(512),
 116 };
 117
 118 static struct usb_descriptor_header *eem_hs_function[] __initdata = {
 119         /* CDC EEM control descriptors */
 120         (struct usb_descriptor_header *) &eem_intf,
 121         (struct usb_descriptor_header *) &eem_hs_in_desc,
 122         (struct usb_descriptor_header *) &eem_hs_out_desc,
 123         NULL,
 124 };
 125
 126 /* string descriptors: */
 127
 128 static struct usb_string eem_string_defs[] = {
 129         [0].s = "CDC Ethernet Emulation Model (EEM)",
 130         {  } /* end of list */
 131 };
 132
 133 static struct usb_gadget_strings eem_string_table = {
 134         .language =             0x0409, /* en-us */
 135         .strings =              eem_string_defs,
 136 };
 137
 138 static struct usb_gadget_strings *eem_strings[] = {
 139         &eem_string_table,
 140         NULL,
 141 };
 142
 143 /*-------------------------------------------------------------------------*/
 144
 145 static int eem_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 146 {
 147         struct usb_composite_dev *cdev = f->config->cdev;
 148         int                     value = -EOPNOTSUPP;
 149         u16                     w_index = le16_to_cpu(ctrl->wIndex);
 150         u16                     w_value = le16_to_cpu(ctrl->wValue);
 151         u16                     w_length = le16_to_cpu(ctrl->wLength);
 152
 153         DBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
 154                 ctrl->bRequestType, ctrl->bRequest,
 155                 w_value, w_index, w_length);
 156
 157         /* device either stalls (value < 0) or reports success */
 158         return value;
 159 }
 160
 161
 162 static int eem_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 163 {
 164         struct f_eem            *eem = func_to_eem(f);
 165         struct usb_composite_dev *cdev = f->config->cdev;
 166         struct net_device       *net;
 167
 168         /* we know alt == 0, so this is an activation or a reset */
 169         if (alt != 0)
 170                 goto fail;
 171
 172         if (intf == eem->ctrl_id) {
 173
 174                 if (eem->port.in_ep->driver_data) {
 175                         DBG(cdev, "reset eem\n");
 176                         gether_disconnect(&eem->port);
 177                 }
 178
 179                 if (!eem->port.in) {
 180                         DBG(cdev, "init eem\n");
 181                         eem->port.in = ep_choose(cdev->gadget,
 182                                         eem->hs.in, eem->fs.in);
 183                         eem->port.out = ep_choose(cdev->gadget,
 184                                         eem->hs.out, eem->fs.out);
 185                 }
 186
 187                 /* zlps should not occur because zero-length EEM packets
 188                  * will be inserted in those cases where they would occur
 189                  */
 190                 eem->port.is_zlp_ok = 1;
 191                 eem->port.cdc_filter = DEFAULT_FILTER;
 192                 DBG(cdev, "activate eem\n");
 193                 net = gether_connect(&eem->port);
 194                 if (IS_ERR(net))
 195                         return PTR_ERR(net);
 196         } else
 197                 goto fail;
 198
 199         return 0;
 200 fail:
 201         return -EINVAL;
 202 }
 203
 204 static void eem_disable(struct usb_function *f)
 205 {
 206         struct f_eem            *eem = func_to_eem(f);
 207         struct usb_composite_dev *cdev = f->config->cdev;
 208
 209         DBG(cdev, "eem deactivated\n");
 210
 211         if (eem->port.in_ep->driver_data)
 212                 gether_disconnect(&eem->port);
 213 }
 214
 215 /*-------------------------------------------------------------------------*/
 216
 217 /* EEM function driver setup/binding */
 218
 219 static int __init
 220 eem_bind(struct usb_configuration *c, struct usb_function *f)
 221 {
 222         struct usb_composite_dev *cdev = c->cdev;
 223         struct f_eem            *eem = func_to_eem(f);
 224         int                     status;
 225         struct usb_ep           *ep;
 226
 227         /* allocate instance-specific interface IDs */
 228         status = usb_interface_id(c, f);
 229         if (status < 0)
 230                 goto fail;
 231         eem->ctrl_id = status;
 232         eem_intf.bInterfaceNumber = status;
 233
 234         status = -ENODEV;
 235
 236         /* allocate instance-specific endpoints */
 237         ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_in_desc);
 238         if (!ep)
 239                 goto fail;
 240         eem->port.in_ep = ep;
 241         ep->driver_data = cdev; /* claim */
 242
 243         ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_out_desc);
 244         if (!ep)
 245                 goto fail;
 246         eem->port.out_ep = ep;
 247         ep->driver_data = cdev; /* claim */
 248
 249         status = -ENOMEM;
 250
 251         /* copy descriptors, and track endpoint copies */
 252         f->descriptors = usb_copy_descriptors(eem_fs_function);
 253         if (!f->descriptors)
 254                 goto fail;
 255
 256         eem->fs.in = usb_find_endpoint(eem_fs_function,
 257                         f->descriptors, &eem_fs_in_desc);
 258         eem->fs.out = usb_find_endpoint(eem_fs_function,
 259                         f->descriptors, &eem_fs_out_desc);
 260
 261         /* support all relevant hardware speeds... we expect that when
 262          * hardware is dual speed, all bulk-capable endpoints work at
 263          * both speeds
 264          */
 265         if (gadget_is_dualspeed(c->cdev->gadget)) {
 266                 eem_hs_in_desc.bEndpointAddress =
 267                                 eem_fs_in_desc.bEndpointAddress;
 268                 eem_hs_out_desc.bEndpointAddress =
 269                                 eem_fs_out_desc.bEndpointAddress;
 270
 271                 /* copy descriptors, and track endpoint copies */
 272                 f->hs_descriptors = usb_copy_descriptors(eem_hs_function);
 273                 if (!f->hs_descriptors)
 274                         goto fail;
 275
 276                 eem->hs.in = usb_find_endpoint(eem_hs_function,
 277                                 f->hs_descriptors, &eem_hs_in_desc);
 278                 eem->hs.out = usb_find_endpoint(eem_hs_function,
 279                                 f->hs_descriptors, &eem_hs_out_desc);
 280         }
 281
 282         DBG(cdev, "CDC Ethernet (EEM): %s speed IN/%s OUT/%s\n",
 283                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 284                         eem->port.in_ep->name, eem->port.out_ep->name);
 285         return 0;
 286
 287 fail:
 288         if (f->descriptors)
 289                 usb_free_descriptors(f->descriptors);
 290
 291         /* we might as well release our claims on endpoints */
 292         if (eem->port.out)
 293                 eem->port.out_ep->driver_data = NULL;
 294         if (eem->port.in)
 295                 eem->port.in_ep->driver_data = NULL;
 296
 297         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 298
 299         return status;
 300 }
 301
 302 static void
 303 eem_unbind(struct usb_configuration *c, struct usb_function *f)
 304 {
 305         struct f_eem    *eem = func_to_eem(f);
 306
 307         DBG(c->cdev, "eem unbind\n");
 308
 309         if (gadget_is_dualspeed(c->cdev->gadget))
 310                 usb_free_descriptors(f->hs_descriptors);
 311         usb_free_descriptors(f->descriptors);
 312         kfree(eem);
 313 }
 314
 315 static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req)
 316 {
 317         struct sk_buff *skb = (struct sk_buff *)req->context;
 318
 319         dev_kfree_skb_any(skb);
 320 }
 321
 322 /*
 323  * Add the EEM header and ethernet checksum.
 324  * We currently do not attempt to put multiple ethernet frames
 325  * into a single USB transfer
 326  */
 327 static struct sk_buff *eem_wrap(struct gether *port, struct sk_buff *skb)
 328 {
 329         struct sk_buff  *skb2 = NULL;
 330         struct usb_ep   *in = port->in_ep;
 331         int             padlen = 0;
 332         u16             len = skb->len;
 333
 334         if (!skb_cloned(skb)) {
 335                 int headroom = skb_headroom(skb);
 336                 int tailroom = skb_tailroom(skb);
 337
 338                 /* When (len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) is 0,
 339                  * stick two bytes of zero-length EEM packet on the end.
 340                  */
 341                 if (((len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) == 0)
 342                         padlen += 2;
 343
 344                 if ((tailroom >= (ETH_FCS_LEN + padlen)) &&
 345                                 (headroom >= EEM_HLEN))
 346                         goto done;
 347         }
 348
 349         skb2 = skb_copy_expand(skb, EEM_HLEN, ETH_FCS_LEN + padlen, GFP_ATOMIC);
 350         dev_kfree_skb_any(skb);
 351         skb = skb2;
 352         if (!skb)
 353                 return skb;
 354
 355 done:
 356         /* use the "no CRC" option */
 357         put_unaligned_be32(0xdeadbeef, skb_put(skb, 4));
 358
 359         /* EEM packet header format:
 360          * b0..13:      length of ethernet frame
 361          * b14:         bmCRC (0 == sentinel CRC)
 362          * b15:         bmType (0 == data)
 363          */
 364         len = skb->len;
 365         put_unaligned_le16(len & 0x3FFF, skb_push(skb, 2));
 366
 367         /* add a zero-length EEM packet, if needed */
 368         if (padlen)
 369                 put_unaligned_le16(0, skb_put(skb, 2));
 370
 371         return skb;
 372 }
 373
 374 /*
 375  * Remove the EEM header.  Note that there can be many EEM packets in a single
 376  * USB transfer, so we need to break them out and handle them independently.
 377  */
 378 static int eem_unwrap(struct gether *port,
 379                         struct sk_buff *skb,
 380                         struct sk_buff_head *list)
 381 {
 382         struct usb_composite_dev        *cdev = port->func.config->cdev;
 383         int                             status = 0;
 384
 385         do {
 386                 struct sk_buff  *skb2;
 387                 u16             header;
 388                 u16             len = 0;
 389
 390                 if (skb->len < EEM_HLEN) {
 391                         status = -EINVAL;
 392                         DBG(cdev, "invalid EEM header\n");
 393                         goto error;
 394                 }
 395
 396                 /* remove the EEM header */
 397                 header = get_unaligned_le16(skb->data);
 398                 skb_pull(skb, EEM_HLEN);
 399
 400                 /* EEM packet header format:
 401                  * b0..14:      EEM type dependent (data or command)
 402                  * b15:         bmType (0 == data, 1 == command)
 403                  */
 404                 if (header & BIT(15)) {
 405                         struct usb_request      *req = cdev->req;
 406                         u16                     bmEEMCmd;
 407
 408                         /* EEM command packet format:
 409                          * b0..10:      bmEEMCmdParam
 410                          * b11..13:     bmEEMCmd
 411                          * b14:         reserved (must be zero)
 412                          * b15:         bmType (1 == command)
 413                          */
 414                         if (header & BIT(14))
 415                                 continue;
 416
 417                         bmEEMCmd = (header >> 11) & 0x7;
 418                         switch (bmEEMCmd) {
 419                         case 0: /* echo */
 420                                 len = header & 0x7FF;
 421                                 if (skb->len < len) {
 422                                         status = -EOVERFLOW;
 423                                         goto error;
 424                                 }
 425
 426                                 skb2 = skb_clone(skb, GFP_ATOMIC);
 427                                 if (unlikely(!skb2)) {
 428                                         DBG(cdev, "EEM echo response error\n");
 429                                         goto next;
 430                                 }
 431                                 skb_trim(skb2, len);
 432                                 put_unaligned_le16(BIT(15) | BIT(11) | len,
 433                                                         skb_push(skb2, 2));
 434                                 skb_copy_bits(skb2, 0, req->buf, skb2->len);
 435                                 req->length = skb2->len;
 436                                 req->complete = eem_cmd_complete;
 437                                 req->zero = 1;
 438                                 req->context = skb2;
 439                                 if (usb_ep_queue(port->in_ep, req, GFP_ATOMIC))
 440                                         DBG(cdev, "echo response queue fail\n");
 441                                 break;
 442
 443                         case 1:  /* echo response */
 444                         case 2:  /* suspend hint */
 445                         case 3:  /* response hint */
 446                         case 4:  /* response complete hint */
 447                         case 5:  /* tickle */
 448                         default: /* reserved */
 449                                 continue;
 450                         }
 451                 } else {
 452                         u32             crc, crc2;
 453                         struct sk_buff  *skb3;
 454
 455                         /* check for zero-length EEM packet */
 456                         if (header == 0)
 457                                 continue;
 458
 459                         /* EEM data packet format:
 460                          * b0..13:      length of ethernet frame
 461                          * b14:         bmCRC (0 == sentinel, 1 == calculated)
 462                          * b15:         bmType (0 == data)
 463                          */
 464                         len = header & 0x3FFF;
 465                         if ((skb->len < len)
 466                                         || (len < (ETH_HLEN + ETH_FCS_LEN))) {
 467                                 status = -EINVAL;
 468                                 goto error;
 469                         }
 470
 471                         /* validate CRC */
 472                         if (header & BIT(14)) {
 473                                 crc = get_unaligned_le32(skb->data + len
 474                                                         - ETH_FCS_LEN);
 475                                 crc2 = ~crc32_le(~0,
 476                                                 skb->data, len - ETH_FCS_LEN);
 477                         } else {
 478                                 crc = get_unaligned_be32(skb->data + len
 479                                                         - ETH_FCS_LEN);
 480                                 crc2 = 0xdeadbeef;
 481                         }
 482                         if (crc != crc2) {
 483                                 DBG(cdev, "invalid EEM CRC\n");
 484                                 goto next;
 485                         }
 486
 487                         skb2 = skb_clone(skb, GFP_ATOMIC);
 488                         if (unlikely(!skb2)) {
 489                                 DBG(cdev, "unable to unframe EEM packet\n");
 490                                 continue;
 491                         }
 492                         skb_trim(skb2, len - ETH_FCS_LEN);
 493
 494                         skb3 = skb_copy_expand(skb2,
 495                                                 NET_IP_ALIGN,
 496                                                 0,
 497                                                 GFP_ATOMIC);
 498                         if (unlikely(!skb3)) {
 499                                 DBG(cdev, "unable to realign EEM packet\n");
 500                                 dev_kfree_skb_any(skb2);
 501                                 continue;
 502                         }
 503                         dev_kfree_skb_any(skb2);
 504                         skb_queue_tail(list, skb3);
 505                 }
 506 next:
 507                 skb_pull(skb, len);
 508         } while (skb->len);
 509
 510 error:
 511         dev_kfree_skb_any(skb);
 512         return status;
 513 }
 514
 515 /**
 516  * eem_bind_config - add CDC Ethernet (EEM) network link to a configuration
 517  * @c: the configuration to support the network link
 518  * Context: single threaded during gadget setup
 519  *
 520  * Returns zero on success, else negative errno.
 521  *
 522  * Caller must have called @gether_setup().  Caller is also responsible
 523  * for calling @gether_cleanup() before module unload.
 524  */
 525 int __init eem_bind_config(struct usb_configuration *c)
 526 {
 527         struct f_eem    *eem;
 528         int             status;
 529
 530         /* maybe allocate device-global string IDs */
 531         if (eem_string_defs[0].id == 0) {
 532
 533                 /* control interface label */
 534                 status = usb_string_id(c->cdev);
 535                 if (status < 0)
 536                         return status;
 537                 eem_string_defs[0].id = status;
 538                 eem_intf.iInterface = status;
 539         }
 540
 541         /* allocate and initialize one new instance */
 542         eem = kzalloc(sizeof *eem, GFP_KERNEL);
 543         if (!eem)
 544                 return -ENOMEM;
 545
 546         eem->port.cdc_filter = DEFAULT_FILTER;
 547
 548         eem->port.func.name = "cdc_eem";
 549         eem->port.func.strings = eem_strings;
 550         /* descriptors are per-instance copies */
 551         eem->port.func.bind = eem_bind;
 552         eem->port.func.unbind = eem_unbind;
 553         eem->port.func.set_alt = eem_set_alt;
 554         eem->port.func.setup = eem_setup;
 555         eem->port.func.disable = eem_disable;
 556         eem->port.wrap = eem_wrap;
 557         eem->port.unwrap = eem_unwrap;
 558         eem->port.header_len = EEM_HLEN;
 559
 560         status = usb_add_function(c, &eem->port.func);
 561         if (status)
 562                 kfree(eem);
 563         return status;
 564 }
 565