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 f_eem {
  39         struct gether                   port;
  40         u8                              ctrl_id;
  41 };
  42
  43 static inline struct f_eem *func_to_eem(struct usb_function *f)
  44 {
  45         return container_of(f, struct f_eem, port.func);
  46 }
  47
  48 /*-------------------------------------------------------------------------*/
  49
  50 /* interface descriptor: */
  51
  52 static struct usb_interface_descriptor eem_intf __initdata = {
  53         .bLength =              sizeof eem_intf,
  54         .bDescriptorType =      USB_DT_INTERFACE,
  55
  56         /* .bInterfaceNumber = DYNAMIC */
  57         .bNumEndpoints =        2,
  58         .bInterfaceClass =      USB_CLASS_COMM,
  59         .bInterfaceSubClass =   USB_CDC_SUBCLASS_EEM,
  60         .bInterfaceProtocol =   USB_CDC_PROTO_EEM,
  61         /* .iInterface = DYNAMIC */
  62 };
  63
  64 /* full speed support: */
  65
  66 static struct usb_endpoint_descriptor eem_fs_in_desc __initdata = {
  67         .bLength =              USB_DT_ENDPOINT_SIZE,
  68         .bDescriptorType =      USB_DT_ENDPOINT,
  69
  70         .bEndpointAddress =     USB_DIR_IN,
  71         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  72 };
  73
  74 static struct usb_endpoint_descriptor eem_fs_out_desc __initdata = {
  75         .bLength =              USB_DT_ENDPOINT_SIZE,
  76         .bDescriptorType =      USB_DT_ENDPOINT,
  77
  78         .bEndpointAddress =     USB_DIR_OUT,
  79         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  80 };
  81
  82 static struct usb_descriptor_header *eem_fs_function[] __initdata = {
  83         /* CDC EEM control descriptors */
  84         (struct usb_descriptor_header *) &eem_intf,
  85         (struct usb_descriptor_header *) &eem_fs_in_desc,
  86         (struct usb_descriptor_header *) &eem_fs_out_desc,
  87         NULL,
  88 };
  89
  90 /* high speed support: */
  91
  92 static struct usb_endpoint_descriptor eem_hs_in_desc __initdata = {
  93         .bLength =              USB_DT_ENDPOINT_SIZE,
  94         .bDescriptorType =      USB_DT_ENDPOINT,
  95
  96         .bEndpointAddress =     USB_DIR_IN,
  97         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  98         .wMaxPacketSize =       cpu_to_le16(512),
  99 };
 100
 101 static struct usb_endpoint_descriptor eem_hs_out_desc __initdata = {
 102         .bLength =              USB_DT_ENDPOINT_SIZE,
 103         .bDescriptorType =      USB_DT_ENDPOINT,
 104
 105         .bEndpointAddress =     USB_DIR_OUT,
 106         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 107         .wMaxPacketSize =       cpu_to_le16(512),
 108 };
 109
 110 static struct usb_descriptor_header *eem_hs_function[] __initdata = {
 111         /* CDC EEM control descriptors */
 112         (struct usb_descriptor_header *) &eem_intf,
 113         (struct usb_descriptor_header *) &eem_hs_in_desc,
 114         (struct usb_descriptor_header *) &eem_hs_out_desc,
 115         NULL,
 116 };
 117
 118 /* super speed support: */
 119
 120 static struct usb_endpoint_descriptor eem_ss_in_desc __initdata = {
 121         .bLength =              USB_DT_ENDPOINT_SIZE,
 122         .bDescriptorType =      USB_DT_ENDPOINT,
 123
 124         .bEndpointAddress =     USB_DIR_IN,
 125         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 126         .wMaxPacketSize =       cpu_to_le16(1024),
 127 };
 128
 129 static struct usb_endpoint_descriptor eem_ss_out_desc __initdata = {
 130         .bLength =              USB_DT_ENDPOINT_SIZE,
 131         .bDescriptorType =      USB_DT_ENDPOINT,
 132
 133         .bEndpointAddress =     USB_DIR_OUT,
 134         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 135         .wMaxPacketSize =       cpu_to_le16(1024),
 136 };
 137
 138 static struct usb_ss_ep_comp_descriptor eem_ss_bulk_comp_desc __initdata = {
 139         .bLength =              sizeof eem_ss_bulk_comp_desc,
 140         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 141
 142         /* the following 2 values can be tweaked if necessary */
 143         /* .bMaxBurst =         0, */
 144         /* .bmAttributes =      0, */
 145 };
 146
 147 static struct usb_descriptor_header *eem_ss_function[] __initdata = {
 148         /* CDC EEM control descriptors */
 149         (struct usb_descriptor_header *) &eem_intf,
 150         (struct usb_descriptor_header *) &eem_ss_in_desc,
 151         (struct usb_descriptor_header *) &eem_ss_bulk_comp_desc,
 152         (struct usb_descriptor_header *) &eem_ss_out_desc,
 153         (struct usb_descriptor_header *) &eem_ss_bulk_comp_desc,
 154         NULL,
 155 };
 156
 157 /* string descriptors: */
 158
 159 static struct usb_string eem_string_defs[] = {
 160         [0].s = "CDC Ethernet Emulation Model (EEM)",
 161         {  } /* end of list */
 162 };
 163
 164 static struct usb_gadget_strings eem_string_table = {
 165         .language =             0x0409, /* en-us */
 166         .strings =              eem_string_defs,
 167 };
 168
 169 static struct usb_gadget_strings *eem_strings[] = {
 170         &eem_string_table,
 171         NULL,
 172 };
 173
 174 /*-------------------------------------------------------------------------*/
 175
 176 static int eem_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 177 {
 178         struct usb_composite_dev *cdev = f->config->cdev;
 179         int                     value = -EOPNOTSUPP;
 180         u16                     w_index = le16_to_cpu(ctrl->wIndex);
 181         u16                     w_value = le16_to_cpu(ctrl->wValue);
 182         u16                     w_length = le16_to_cpu(ctrl->wLength);
 183
 184         DBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
 185                 ctrl->bRequestType, ctrl->bRequest,
 186                 w_value, w_index, w_length);
 187
 188         /* device either stalls (value < 0) or reports success */
 189         return value;
 190 }
 191
 192
 193 static int eem_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 194 {
 195         struct f_eem            *eem = func_to_eem(f);
 196         struct usb_composite_dev *cdev = f->config->cdev;
 197         struct net_device       *net;
 198
 199         /* we know alt == 0, so this is an activation or a reset */
 200         if (alt != 0)
 201                 goto fail;
 202
 203         if (intf == eem->ctrl_id) {
 204
 205                 if (eem->port.in_ep->driver_data) {
 206                         DBG(cdev, "reset eem\n");
 207                         gether_disconnect(&eem->port);
 208                 }
 209
 210                 if (!eem->port.in_ep->desc || !eem->port.out_ep->desc) {
 211                         DBG(cdev, "init eem\n");
 212                         if (config_ep_by_speed(cdev->gadget, f,
 213                                                eem->port.in_ep) ||
 214                             config_ep_by_speed(cdev->gadget, f,
 215                                                eem->port.out_ep)) {
 216                                 eem->port.in_ep->desc = NULL;
 217                                 eem->port.out_ep->desc = NULL;
 218                                 goto fail;
 219                         }
 220                 }
 221
 222                 /* zlps should not occur because zero-length EEM packets
 223                  * will be inserted in those cases where they would occur
 224                  */
 225                 eem->port.is_zlp_ok = 1;
 226                 eem->port.cdc_filter = DEFAULT_FILTER;
 227                 DBG(cdev, "activate eem\n");
 228                 net = gether_connect(&eem->port);
 229                 if (IS_ERR(net))
 230                         return PTR_ERR(net);
 231         } else
 232                 goto fail;
 233
 234         return 0;
 235 fail:
 236         return -EINVAL;
 237 }
 238
 239 static void eem_disable(struct usb_function *f)
 240 {
 241         struct f_eem            *eem = func_to_eem(f);
 242         struct usb_composite_dev *cdev = f->config->cdev;
 243
 244         DBG(cdev, "eem deactivated\n");
 245
 246         if (eem->port.in_ep->driver_data)
 247                 gether_disconnect(&eem->port);
 248 }
 249
 250 /*-------------------------------------------------------------------------*/
 251
 252 /* EEM function driver setup/binding */
 253
 254 static int __init
 255 eem_bind(struct usb_configuration *c, struct usb_function *f)
 256 {
 257         struct usb_composite_dev *cdev = c->cdev;
 258         struct f_eem            *eem = func_to_eem(f);
 259         int                     status;
 260         struct usb_ep           *ep;
 261
 262         /* allocate instance-specific interface IDs */
 263         status = usb_interface_id(c, f);
 264         if (status < 0)
 265                 goto fail;
 266         eem->ctrl_id = status;
 267         eem_intf.bInterfaceNumber = status;
 268
 269         status = -ENODEV;
 270
 271         /* allocate instance-specific endpoints */
 272         ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_in_desc);
 273         if (!ep)
 274                 goto fail;
 275         eem->port.in_ep = ep;
 276         ep->driver_data = cdev; /* claim */
 277
 278         ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_out_desc);
 279         if (!ep)
 280                 goto fail;
 281         eem->port.out_ep = ep;
 282         ep->driver_data = cdev; /* claim */
 283
 284         status = -ENOMEM;
 285
 286         /* copy descriptors, and track endpoint copies */
 287         f->descriptors = usb_copy_descriptors(eem_fs_function);
 288         if (!f->descriptors)
 289                 goto fail;
 290
 291         /* support all relevant hardware speeds... we expect that when
 292          * hardware is dual speed, all bulk-capable endpoints work at
 293          * both speeds
 294          */
 295         if (gadget_is_dualspeed(c->cdev->gadget)) {
 296                 eem_hs_in_desc.bEndpointAddress =
 297                                 eem_fs_in_desc.bEndpointAddress;
 298                 eem_hs_out_desc.bEndpointAddress =
 299                                 eem_fs_out_desc.bEndpointAddress;
 300
 301                 /* copy descriptors, and track endpoint copies */
 302                 f->hs_descriptors = usb_copy_descriptors(eem_hs_function);
 303                 if (!f->hs_descriptors)
 304                         goto fail;
 305         }
 306
 307         if (gadget_is_superspeed(c->cdev->gadget)) {
 308                 eem_ss_in_desc.bEndpointAddress =
 309                                 eem_fs_in_desc.bEndpointAddress;
 310                 eem_ss_out_desc.bEndpointAddress =
 311                                 eem_fs_out_desc.bEndpointAddress;
 312
 313                 /* copy descriptors, and track endpoint copies */
 314                 f->ss_descriptors = usb_copy_descriptors(eem_ss_function);
 315                 if (!f->ss_descriptors)
 316                         goto fail;
 317         }
 318
 319         DBG(cdev, "CDC Ethernet (EEM): %s speed IN/%s OUT/%s\n",
 320                         gadget_is_superspeed(c->cdev->gadget) ? "super" :
 321                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 322                         eem->port.in_ep->name, eem->port.out_ep->name);
 323         return 0;
 324
 325 fail:
 326         if (f->descriptors)
 327                 usb_free_descriptors(f->descriptors);
 328         if (f->hs_descriptors)
 329                 usb_free_descriptors(f->hs_descriptors);
 330
 331         /* we might as well release our claims on endpoints */
 332         if (eem->port.out_ep->desc)
 333                 eem->port.out_ep->driver_data = NULL;
 334         if (eem->port.in_ep->desc)
 335                 eem->port.in_ep->driver_data = NULL;
 336
 337         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 338
 339         return status;
 340 }
 341
 342 static void
 343 eem_unbind(struct usb_configuration *c, struct usb_function *f)
 344 {
 345         struct f_eem    *eem = func_to_eem(f);
 346
 347         DBG(c->cdev, "eem unbind\n");
 348
 349         if (gadget_is_superspeed(c->cdev->gadget))
 350                 usb_free_descriptors(f->ss_descriptors);
 351         if (gadget_is_dualspeed(c->cdev->gadget))
 352                 usb_free_descriptors(f->hs_descriptors);
 353         usb_free_descriptors(f->descriptors);
 354         kfree(eem);
 355 }
 356
 357 static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req)
 358 {
 359         struct sk_buff *skb = (struct sk_buff *)req->context;
 360
 361         dev_kfree_skb_any(skb);
 362 }
 363
 364 /*
 365  * Add the EEM header and ethernet checksum.
 366  * We currently do not attempt to put multiple ethernet frames
 367  * into a single USB transfer
 368  */
 369 static struct sk_buff *eem_wrap(struct gether *port, struct sk_buff *skb)
 370 {
 371         struct sk_buff  *skb2 = NULL;
 372         struct usb_ep   *in = port->in_ep;
 373         int             padlen = 0;
 374         u16             len = skb->len;
 375
 376         if (!skb_cloned(skb)) {
 377                 int headroom = skb_headroom(skb);
 378                 int tailroom = skb_tailroom(skb);
 379
 380                 /* When (len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) is 0,
 381                  * stick two bytes of zero-length EEM packet on the end.
 382                  */
 383                 if (((len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) == 0)
 384                         padlen += 2;
 385
 386                 if ((tailroom >= (ETH_FCS_LEN + padlen)) &&
 387                                 (headroom >= EEM_HLEN))
 388                         goto done;
 389         }
 390
 391         skb2 = skb_copy_expand(skb, EEM_HLEN, ETH_FCS_LEN + padlen, GFP_ATOMIC);
 392         dev_kfree_skb_any(skb);
 393         skb = skb2;
 394         if (!skb)
 395                 return skb;
 396
 397 done:
 398         /* use the "no CRC" option */
 399         put_unaligned_be32(0xdeadbeef, skb_put(skb, 4));
 400
 401         /* EEM packet header format:
 402          * b0..13:      length of ethernet frame
 403          * b14:         bmCRC (0 == sentinel CRC)
 404          * b15:         bmType (0 == data)
 405          */
 406         len = skb->len;
 407         put_unaligned_le16(len & 0x3FFF, skb_push(skb, 2));
 408
 409         /* add a zero-length EEM packet, if needed */
 410         if (padlen)
 411                 put_unaligned_le16(0, skb_put(skb, 2));
 412
 413         return skb;
 414 }
 415
 416 /*
 417  * Remove the EEM header.  Note that there can be many EEM packets in a single
 418  * USB transfer, so we need to break them out and handle them independently.
 419  */
 420 static int eem_unwrap(struct gether *port,
 421                         struct sk_buff *skb,
 422                         struct sk_buff_head *list)
 423 {
 424         struct usb_composite_dev        *cdev = port->func.config->cdev;
 425         int                             status = 0;
 426
 427         do {
 428                 struct sk_buff  *skb2;
 429                 u16             header;
 430                 u16             len = 0;
 431
 432                 if (skb->len < EEM_HLEN) {
 433                         status = -EINVAL;
 434                         DBG(cdev, "invalid EEM header\n");
 435                         goto error;
 436                 }
 437
 438                 /* remove the EEM header */
 439                 header = get_unaligned_le16(skb->data);
 440                 skb_pull(skb, EEM_HLEN);
 441
 442                 /* EEM packet header format:
 443                  * b0..14:      EEM type dependent (data or command)
 444                  * b15:         bmType (0 == data, 1 == command)
 445                  */
 446                 if (header & BIT(15)) {
 447                         struct usb_request      *req = cdev->req;
 448                         u16                     bmEEMCmd;
 449
 450                         /* EEM command packet format:
 451                          * b0..10:      bmEEMCmdParam
 452                          * b11..13:     bmEEMCmd
 453                          * b14:         reserved (must be zero)
 454                          * b15:         bmType (1 == command)
 455                          */
 456                         if (header & BIT(14))
 457                                 continue;
 458
 459                         bmEEMCmd = (header >> 11) & 0x7;
 460                         switch (bmEEMCmd) {
 461                         case 0: /* echo */
 462                                 len = header & 0x7FF;
 463                                 if (skb->len < len) {
 464                                         status = -EOVERFLOW;
 465                                         goto error;
 466                                 }
 467
 468                                 skb2 = skb_clone(skb, GFP_ATOMIC);
 469                                 if (unlikely(!skb2)) {
 470                                         DBG(cdev, "EEM echo response error\n");
 471                                         goto next;
 472                                 }
 473                                 skb_trim(skb2, len);
 474                                 put_unaligned_le16(BIT(15) | BIT(11) | len,
 475                                                         skb_push(skb2, 2));
 476                                 skb_copy_bits(skb2, 0, req->buf, skb2->len);
 477                                 req->length = skb2->len;
 478                                 req->complete = eem_cmd_complete;
 479                                 req->zero = 1;
 480                                 req->context = skb2;
 481                                 if (usb_ep_queue(port->in_ep, req, GFP_ATOMIC))
 482                                         DBG(cdev, "echo response queue fail\n");
 483                                 break;
 484
 485                         case 1:  /* echo response */
 486                         case 2:  /* suspend hint */
 487                         case 3:  /* response hint */
 488                         case 4:  /* response complete hint */
 489                         case 5:  /* tickle */
 490                         default: /* reserved */
 491                                 continue;
 492                         }
 493                 } else {
 494                         u32             crc, crc2;
 495                         struct sk_buff  *skb3;
 496
 497                         /* check for zero-length EEM packet */
 498                         if (header == 0)
 499                                 continue;
 500
 501                         /* EEM data packet format:
 502                          * b0..13:      length of ethernet frame
 503                          * b14:         bmCRC (0 == sentinel, 1 == calculated)
 504                          * b15:         bmType (0 == data)
 505                          */
 506                         len = header & 0x3FFF;
 507                         if ((skb->len < len)
 508                                         || (len < (ETH_HLEN + ETH_FCS_LEN))) {
 509                                 status = -EINVAL;
 510                                 goto error;
 511                         }
 512
 513                         /* validate CRC */
 514                         if (header & BIT(14)) {
 515                                 crc = get_unaligned_le32(skb->data + len
 516                                                         - ETH_FCS_LEN);
 517                                 crc2 = ~crc32_le(~0,
 518                                                 skb->data, len - ETH_FCS_LEN);
 519                         } else {
 520                                 crc = get_unaligned_be32(skb->data + len
 521                                                         - ETH_FCS_LEN);
 522                                 crc2 = 0xdeadbeef;
 523                         }
 524                         if (crc != crc2) {
 525                                 DBG(cdev, "invalid EEM CRC\n");
 526                                 goto next;
 527                         }
 528
 529                         skb2 = skb_clone(skb, GFP_ATOMIC);
 530                         if (unlikely(!skb2)) {
 531                                 DBG(cdev, "unable to unframe EEM packet\n");
 532                                 continue;
 533                         }
 534                         skb_trim(skb2, len - ETH_FCS_LEN);
 535
 536                         skb3 = skb_copy_expand(skb2,
 537                                                 NET_IP_ALIGN,
 538                                                 0,
 539                                                 GFP_ATOMIC);
 540                         if (unlikely(!skb3)) {
 541                                 DBG(cdev, "unable to realign EEM packet\n");
 542                                 dev_kfree_skb_any(skb2);
 543                                 continue;
 544                         }
 545                         dev_kfree_skb_any(skb2);
 546                         skb_queue_tail(list, skb3);
 547                 }
 548 next:
 549                 skb_pull(skb, len);
 550         } while (skb->len);
 551
 552 error:
 553         dev_kfree_skb_any(skb);
 554         return status;
 555 }
 556
 557 /**
 558  * eem_bind_config - add CDC Ethernet (EEM) network link to a configuration
 559  * @c: the configuration to support the network link
 560  * Context: single threaded during gadget setup
 561  *
 562  * Returns zero on success, else negative errno.
 563  *
 564  * Caller must have called @gether_setup().  Caller is also responsible
 565  * for calling @gether_cleanup() before module unload.
 566  */
 567 int __init eem_bind_config(struct usb_configuration *c)
 568 {
 569         struct f_eem    *eem;
 570         int             status;
 571
 572         /* maybe allocate device-global string IDs */
 573         if (eem_string_defs[0].id == 0) {
 574
 575                 /* control interface label */
 576                 status = usb_string_id(c->cdev);
 577                 if (status < 0)
 578                         return status;
 579                 eem_string_defs[0].id = status;
 580                 eem_intf.iInterface = status;
 581         }
 582
 583         /* allocate and initialize one new instance */
 584         eem = kzalloc(sizeof *eem, GFP_KERNEL);
 585         if (!eem)
 586                 return -ENOMEM;
 587
 588         eem->port.cdc_filter = DEFAULT_FILTER;
 589
 590         eem->port.func.name = "cdc_eem";
 591         eem->port.func.strings = eem_strings;
 592         /* descriptors are per-instance copies */
 593         eem->port.func.bind = eem_bind;
 594         eem->port.func.unbind = eem_unbind;
 595         eem->port.func.set_alt = eem_set_alt;
 596         eem->port.func.setup = eem_setup;
 597         eem->port.func.disable = eem_disable;
 598         eem->port.wrap = eem_wrap;
 599         eem->port.unwrap = eem_unwrap;
 600         eem->port.header_len = EEM_HLEN;
 601
 602         status = usb_add_function(c, &eem->port.func);
 603         if (status)
 604                 kfree(eem);
 605         return status;
 606 }
 607