drivers/usb/gadget/f_subset.c

   1 /*
   2  * f_subset.c -- "CDC Subset" Ethernet link function driver
   3  *
   4  * Copyright (C) 2003-2005,2008 David Brownell
   5  * Copyright (C) 2008 Nokia Corporation
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  */
  12
  13 #include <linux/slab.h>
  14 #include <linux/kernel.h>
  15 #include <linux/device.h>
  16 #include <linux/etherdevice.h>
  17
  18 #include "u_ether.h"
  19
  20
  21 /*
  22  * This function packages a simple "CDC Subset" Ethernet port with no real
  23  * control mechanisms; just raw data transfer over two bulk endpoints.
  24  * The data transfer model is exactly that of CDC Ethernet, which is
  25  * why we call it the "CDC Subset".
  26  *
  27  * Because it's not standardized, this has some interoperability issues.
  28  * They mostly relate to driver binding, since the data transfer model is
  29  * so simple (CDC Ethernet).  The original versions of this protocol used
  30  * specific product/vendor IDs:  byteswapped IDs for Digital Equipment's
  31  * SA-1100 "Itsy" board, which could run Linux 2.4 kernels and supported
  32  * daughtercards with USB peripheral connectors.  (It was used more often
  33  * with other boards, using the Itsy identifiers.)  Linux hosts recognized
  34  * this with CONFIG_USB_ARMLINUX; these devices have only one configuration
  35  * and one interface.
  36  *
  37  * At some point, MCCI defined a (nonconformant) CDC MDLM variant called
  38  * "SAFE", which happens to have a mode which is identical to the "CDC
  39  * Subset" in terms of data transfer and lack of control model.  This was
  40  * adopted by later Sharp Zaurus models, and by some other software which
  41  * Linux hosts recognize with CONFIG_USB_NET_ZAURUS.
  42  *
  43  * Because Microsoft's RNDIS drivers are far from robust, we added a few
  44  * descriptors to the CDC Subset code, making this code look like a SAFE
  45  * implementation.  This lets you use MCCI's host side MS-Windows drivers
  46  * if you get fed up with RNDIS.  It also makes it easier for composite
  47  * drivers to work, since they can use class based binding instead of
  48  * caring about specific product and vendor IDs.
  49  */
  50
  51 struct f_gether {
  52         struct gether                   port;
  53
  54         char                            ethaddr[14];
  55 };
  56
  57 static inline struct f_gether *func_to_geth(struct usb_function *f)
  58 {
  59         return container_of(f, struct f_gether, port.func);
  60 }
  61
  62 /*-------------------------------------------------------------------------*/
  63
  64 /*
  65  * "Simple" CDC-subset option is a simple vendor-neutral model that most
  66  * full speed controllers can handle:  one interface, two bulk endpoints.
  67  * To assist host side drivers, we fancy it up a bit, and add descriptors so
  68  * some host side drivers will understand it as a "SAFE" variant.
  69  *
  70  * "SAFE" loosely follows CDC WMC MDLM, violating the spec in various ways.
  71  * Data endpoints live in the control interface, there's no data interface.
  72  * And it's not used to talk to a cell phone radio.
  73  */
  74
  75 /* interface descriptor: */
  76
  77 static struct usb_interface_descriptor subset_data_intf = {
  78         .bLength =              sizeof subset_data_intf,
  79         .bDescriptorType =      USB_DT_INTERFACE,
  80
  81         /* .bInterfaceNumber = DYNAMIC */
  82         .bAlternateSetting =    0,
  83         .bNumEndpoints =        2,
  84         .bInterfaceClass =      USB_CLASS_COMM,
  85         .bInterfaceSubClass =   USB_CDC_SUBCLASS_MDLM,
  86         .bInterfaceProtocol =   0,
  87         /* .iInterface = DYNAMIC */
  88 };
  89
  90 static struct usb_cdc_header_desc mdlm_header_desc = {
  91         .bLength =              sizeof mdlm_header_desc,
  92         .bDescriptorType =      USB_DT_CS_INTERFACE,
  93         .bDescriptorSubType =   USB_CDC_HEADER_TYPE,
  94
  95         .bcdCDC =               cpu_to_le16(0x0110),
  96 };
  97
  98 static struct usb_cdc_mdlm_desc mdlm_desc = {
  99         .bLength =              sizeof mdlm_desc,
 100         .bDescriptorType =      USB_DT_CS_INTERFACE,
 101         .bDescriptorSubType =   USB_CDC_MDLM_TYPE,
 102
 103         .bcdVersion =           cpu_to_le16(0x0100),
 104         .bGUID = {
 105                 0x5d, 0x34, 0xcf, 0x66, 0x11, 0x18, 0x11, 0xd6,
 106                 0xa2, 0x1a, 0x00, 0x01, 0x02, 0xca, 0x9a, 0x7f,
 107         },
 108 };
 109
 110 /* since "usb_cdc_mdlm_detail_desc" is a variable length structure, we
 111  * can't really use its struct.  All we do here is say that we're using
 112  * the submode of "SAFE" which directly matches the CDC Subset.
 113  */
 114 static u8 mdlm_detail_desc[] = {
 115         6,
 116         USB_DT_CS_INTERFACE,
 117         USB_CDC_MDLM_DETAIL_TYPE,
 118
 119         0,      /* "SAFE" */
 120         0,      /* network control capabilities (none) */
 121         0,      /* network data capabilities ("raw" encapsulation) */
 122 };
 123
 124 static struct usb_cdc_ether_desc ether_desc = {
 125         .bLength =              sizeof ether_desc,
 126         .bDescriptorType =      USB_DT_CS_INTERFACE,
 127         .bDescriptorSubType =   USB_CDC_ETHERNET_TYPE,
 128
 129         /* this descriptor actually adds value, surprise! */
 130         /* .iMACAddress = DYNAMIC */
 131         .bmEthernetStatistics = cpu_to_le32(0), /* no statistics */
 132         .wMaxSegmentSize =      cpu_to_le16(ETH_FRAME_LEN),
 133         .wNumberMCFilters =     cpu_to_le16(0),
 134         .bNumberPowerFilters =  0,
 135 };
 136
 137 /* full speed support: */
 138
 139 static struct usb_endpoint_descriptor fs_subset_in_desc = {
 140         .bLength =              USB_DT_ENDPOINT_SIZE,
 141         .bDescriptorType =      USB_DT_ENDPOINT,
 142
 143         .bEndpointAddress =     USB_DIR_IN,
 144         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 145 };
 146
 147 static struct usb_endpoint_descriptor fs_subset_out_desc = {
 148         .bLength =              USB_DT_ENDPOINT_SIZE,
 149         .bDescriptorType =      USB_DT_ENDPOINT,
 150
 151         .bEndpointAddress =     USB_DIR_OUT,
 152         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 153 };
 154
 155 static struct usb_descriptor_header *fs_eth_function[] = {
 156         (struct usb_descriptor_header *) &subset_data_intf,
 157         (struct usb_descriptor_header *) &mdlm_header_desc,
 158         (struct usb_descriptor_header *) &mdlm_desc,
 159         (struct usb_descriptor_header *) &mdlm_detail_desc,
 160         (struct usb_descriptor_header *) &ether_desc,
 161         (struct usb_descriptor_header *) &fs_subset_in_desc,
 162         (struct usb_descriptor_header *) &fs_subset_out_desc,
 163         NULL,
 164 };
 165
 166 /* high speed support: */
 167
 168 static struct usb_endpoint_descriptor hs_subset_in_desc = {
 169         .bLength =              USB_DT_ENDPOINT_SIZE,
 170         .bDescriptorType =      USB_DT_ENDPOINT,
 171
 172         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 173         .wMaxPacketSize =       cpu_to_le16(512),
 174 };
 175
 176 static struct usb_endpoint_descriptor hs_subset_out_desc = {
 177         .bLength =              USB_DT_ENDPOINT_SIZE,
 178         .bDescriptorType =      USB_DT_ENDPOINT,
 179
 180         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 181         .wMaxPacketSize =       cpu_to_le16(512),
 182 };
 183
 184 static struct usb_descriptor_header *hs_eth_function[] = {
 185         (struct usb_descriptor_header *) &subset_data_intf,
 186         (struct usb_descriptor_header *) &mdlm_header_desc,
 187         (struct usb_descriptor_header *) &mdlm_desc,
 188         (struct usb_descriptor_header *) &mdlm_detail_desc,
 189         (struct usb_descriptor_header *) &ether_desc,
 190         (struct usb_descriptor_header *) &hs_subset_in_desc,
 191         (struct usb_descriptor_header *) &hs_subset_out_desc,
 192         NULL,
 193 };
 194
 195 /* super speed support: */
 196
 197 static struct usb_endpoint_descriptor ss_subset_in_desc = {
 198         .bLength =              USB_DT_ENDPOINT_SIZE,
 199         .bDescriptorType =      USB_DT_ENDPOINT,
 200
 201         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 202         .wMaxPacketSize =       cpu_to_le16(1024),
 203 };
 204
 205 static struct usb_endpoint_descriptor ss_subset_out_desc = {
 206         .bLength =              USB_DT_ENDPOINT_SIZE,
 207         .bDescriptorType =      USB_DT_ENDPOINT,
 208
 209         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 210         .wMaxPacketSize =       cpu_to_le16(1024),
 211 };
 212
 213 static struct usb_ss_ep_comp_descriptor ss_subset_bulk_comp_desc = {
 214         .bLength =              sizeof ss_subset_bulk_comp_desc,
 215         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 216
 217         /* the following 2 values can be tweaked if necessary */
 218         /* .bMaxBurst =         0, */
 219         /* .bmAttributes =      0, */
 220 };
 221
 222 static struct usb_descriptor_header *ss_eth_function[] = {
 223         (struct usb_descriptor_header *) &subset_data_intf,
 224         (struct usb_descriptor_header *) &mdlm_header_desc,
 225         (struct usb_descriptor_header *) &mdlm_desc,
 226         (struct usb_descriptor_header *) &mdlm_detail_desc,
 227         (struct usb_descriptor_header *) &ether_desc,
 228         (struct usb_descriptor_header *) &ss_subset_in_desc,
 229         (struct usb_descriptor_header *) &ss_subset_bulk_comp_desc,
 230         (struct usb_descriptor_header *) &ss_subset_out_desc,
 231         (struct usb_descriptor_header *) &ss_subset_bulk_comp_desc,
 232         NULL,
 233 };
 234
 235 /* string descriptors: */
 236
 237 static struct usb_string geth_string_defs[] = {
 238         [0].s = "CDC Ethernet Subset/SAFE",
 239         [1].s = NULL /* DYNAMIC */,
 240         {  } /* end of list */
 241 };
 242
 243 static struct usb_gadget_strings geth_string_table = {
 244         .language =             0x0409, /* en-us */
 245         .strings =              geth_string_defs,
 246 };
 247
 248 static struct usb_gadget_strings *geth_strings[] = {
 249         &geth_string_table,
 250         NULL,
 251 };
 252
 253 /*-------------------------------------------------------------------------*/
 254
 255 static int geth_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 256 {
 257         struct f_gether         *geth = func_to_geth(f);
 258         struct usb_composite_dev *cdev = f->config->cdev;
 259         struct net_device       *net;
 260
 261         /* we know alt == 0, so this is an activation or a reset */
 262
 263         if (geth->port.in_ep->driver_data) {
 264                 DBG(cdev, "reset cdc subset\n");
 265                 gether_disconnect(&geth->port);
 266         }
 267
 268         DBG(cdev, "init + activate cdc subset\n");
 269         if (config_ep_by_speed(cdev->gadget, f, geth->port.in_ep) ||
 270             config_ep_by_speed(cdev->gadget, f, geth->port.out_ep)) {
 271                 geth->port.in_ep->desc = NULL;
 272                 geth->port.out_ep->desc = NULL;
 273                 return -EINVAL;
 274         }
 275
 276         net = gether_connect(&geth->port);
 277         return IS_ERR(net) ? PTR_ERR(net) : 0;
 278 }
 279
 280 static void geth_disable(struct usb_function *f)
 281 {
 282         struct f_gether *geth = func_to_geth(f);
 283         struct usb_composite_dev *cdev = f->config->cdev;
 284
 285         DBG(cdev, "net deactivated\n");
 286         gether_disconnect(&geth->port);
 287 }
 288
 289 /*-------------------------------------------------------------------------*/
 290
 291 /* serial function driver setup/binding */
 292
 293 static int
 294 geth_bind(struct usb_configuration *c, struct usb_function *f)
 295 {
 296         struct usb_composite_dev *cdev = c->cdev;
 297         struct f_gether         *geth = func_to_geth(f);
 298         int                     status;
 299         struct usb_ep           *ep;
 300
 301         /* allocate instance-specific interface IDs */
 302         status = usb_interface_id(c, f);
 303         if (status < 0)
 304                 goto fail;
 305         subset_data_intf.bInterfaceNumber = status;
 306
 307         status = -ENODEV;
 308
 309         /* allocate instance-specific endpoints */
 310         ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_in_desc);
 311         if (!ep)
 312                 goto fail;
 313         geth->port.in_ep = ep;
 314         ep->driver_data = cdev; /* claim */
 315
 316         ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_out_desc);
 317         if (!ep)
 318                 goto fail;
 319         geth->port.out_ep = ep;
 320         ep->driver_data = cdev; /* claim */
 321
 322         /* copy descriptors, and track endpoint copies */
 323         f->descriptors = usb_copy_descriptors(fs_eth_function);
 324         if (!f->descriptors)
 325                 goto fail;
 326
 327         /* support all relevant hardware speeds... we expect that when
 328          * hardware is dual speed, all bulk-capable endpoints work at
 329          * both speeds
 330          */
 331         if (gadget_is_dualspeed(c->cdev->gadget)) {
 332                 hs_subset_in_desc.bEndpointAddress =
 333                                 fs_subset_in_desc.bEndpointAddress;
 334                 hs_subset_out_desc.bEndpointAddress =
 335                                 fs_subset_out_desc.bEndpointAddress;
 336
 337                 /* copy descriptors, and track endpoint copies */
 338                 f->hs_descriptors = usb_copy_descriptors(hs_eth_function);
 339                 if (!f->hs_descriptors)
 340                         goto fail;
 341         }
 342
 343         if (gadget_is_superspeed(c->cdev->gadget)) {
 344                 ss_subset_in_desc.bEndpointAddress =
 345                                 fs_subset_in_desc.bEndpointAddress;
 346                 ss_subset_out_desc.bEndpointAddress =
 347                                 fs_subset_out_desc.bEndpointAddress;
 348
 349                 /* copy descriptors, and track endpoint copies */
 350                 f->ss_descriptors = usb_copy_descriptors(ss_eth_function);
 351                 if (!f->ss_descriptors)
 352                         goto fail;
 353         }
 354
 355         /* NOTE:  all that is done without knowing or caring about
 356          * the network link ... which is unavailable to this code
 357          * until we're activated via set_alt().
 358          */
 359
 360         DBG(cdev, "CDC Subset: %s speed IN/%s OUT/%s\n",
 361                         gadget_is_superspeed(c->cdev->gadget) ? "super" :
 362                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 363                         geth->port.in_ep->name, geth->port.out_ep->name);
 364         return 0;
 365
 366 fail:
 367         if (f->descriptors)
 368                 usb_free_descriptors(f->descriptors);
 369         if (f->hs_descriptors)
 370                 usb_free_descriptors(f->hs_descriptors);
 371
 372         /* we might as well release our claims on endpoints */
 373         if (geth->port.out_ep->desc)
 374                 geth->port.out_ep->driver_data = NULL;
 375         if (geth->port.in_ep->desc)
 376                 geth->port.in_ep->driver_data = NULL;
 377
 378         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 379
 380         return status;
 381 }
 382
 383 static void
 384 geth_unbind(struct usb_configuration *c, struct usb_function *f)
 385 {
 386         if (gadget_is_superspeed(c->cdev->gadget))
 387                 usb_free_descriptors(f->ss_descriptors);
 388         if (gadget_is_dualspeed(c->cdev->gadget))
 389                 usb_free_descriptors(f->hs_descriptors);
 390         usb_free_descriptors(f->descriptors);
 391         geth_string_defs[1].s = NULL;
 392         kfree(func_to_geth(f));
 393 }
 394
 395 /**
 396  * geth_bind_config - add CDC Subset network link to a configuration
 397  * @c: the configuration to support the network link
 398  * @ethaddr: a buffer in which the ethernet address of the host side
 399  *      side of the link was recorded
 400  * Context: single threaded during gadget setup
 401  *
 402  * Returns zero on success, else negative errno.
 403  *
 404  * Caller must have called @gether_setup().  Caller is also responsible
 405  * for calling @gether_cleanup() before module unload.
 406  */
 407 int geth_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN])
 408 {
 409         struct f_gether *geth;
 410         int             status;
 411
 412         if (!ethaddr)
 413                 return -EINVAL;
 414
 415         /* maybe allocate device-global string IDs */
 416         if (geth_string_defs[0].id == 0) {
 417
 418                 /* interface label */
 419                 status = usb_string_id(c->cdev);
 420                 if (status < 0)
 421                         return status;
 422                 geth_string_defs[0].id = status;
 423                 subset_data_intf.iInterface = status;
 424
 425                 /* MAC address */
 426                 status = usb_string_id(c->cdev);
 427                 if (status < 0)
 428                         return status;
 429                 geth_string_defs[1].id = status;
 430                 ether_desc.iMACAddress = status;
 431         }
 432
 433         /* allocate and initialize one new instance */
 434         geth = kzalloc(sizeof *geth, GFP_KERNEL);
 435         if (!geth)
 436                 return -ENOMEM;
 437
 438         /* export host's Ethernet address in CDC format */
 439         snprintf(geth->ethaddr, sizeof geth->ethaddr,
 440                 "%02X%02X%02X%02X%02X%02X",
 441                 ethaddr[0], ethaddr[1], ethaddr[2],
 442                 ethaddr[3], ethaddr[4], ethaddr[5]);
 443         geth_string_defs[1].s = geth->ethaddr;
 444
 445         geth->port.cdc_filter = DEFAULT_FILTER;
 446
 447         geth->port.func.name = "cdc_subset";
 448         geth->port.func.strings = geth_strings;
 449         geth->port.func.bind = geth_bind;
 450         geth->port.func.unbind = geth_unbind;
 451         geth->port.func.set_alt = geth_set_alt;
 452         geth->port.func.disable = geth_disable;
 453
 454         status = usb_add_function(c, &geth->port.func);
 455         if (status) {
 456                 geth_string_defs[1].s = NULL;
 457                 kfree(geth);
 458         }
 459         return status;
 460 }