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