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  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include <linux/slab.h>
  23 #include <linux/kernel.h>
  24 #include <linux/device.h>
  25 #include <linux/etherdevice.h>
  26
  27 #include "u_ether.h"
  28
  29
  30 /*
  31  * This function packages a simple "CDC Subset" Ethernet port with no real
  32  * control mechanisms; just raw data transfer over two bulk endpoints.
  33  * The data transfer model is exactly that of CDC Ethernet, which is
  34  * why we call it the "CDC Subset".
  35  *
  36  * Because it's not standardized, this has some interoperability issues.
  37  * They mostly relate to driver binding, since the data transfer model is
  38  * so simple (CDC Ethernet).  The original versions of this protocol used
  39  * specific product/vendor IDs:  byteswapped IDs for Digital Equipment's
  40  * SA-1100 "Itsy" board, which could run Linux 2.4 kernels and supported
  41  * daughtercards with USB peripheral connectors.  (It was used more often
  42  * with other boards, using the Itsy identifiers.)  Linux hosts recognized
  43  * this with CONFIG_USB_ARMLINUX; these devices have only one configuration
  44  * and one interface.
  45  *
  46  * At some point, MCCI defined a (nonconformant) CDC MDLM variant called
  47  * "SAFE", which happens to have a mode which is identical to the "CDC
  48  * Subset" in terms of data transfer and lack of control model.  This was
  49  * adopted by later Sharp Zaurus models, and by some other software which
  50  * Linux hosts recognize with CONFIG_USB_NET_ZAURUS.
  51  *
  52  * Because Microsoft's RNDIS drivers are far from robust, we added a few
  53  * descriptors to the CDC Subset code, making this code look like a SAFE
  54  * implementation.  This lets you use MCCI's host side MS-Windows drivers
  55  * if you get fed up with RNDIS.  It also makes it easier for composite
  56  * drivers to work, since they can use class based binding instead of
  57  * caring about specific product and vendor IDs.
  58  */
  59
  60 struct geth_descs {
  61         struct usb_endpoint_descriptor  *in;
  62         struct usb_endpoint_descriptor  *out;
  63 };
  64
  65 struct f_gether {
  66         struct gether                   port;
  67
  68         char                            ethaddr[14];
  69
  70         struct geth_descs               fs;
  71         struct geth_descs               hs;
  72 };
  73
  74 static inline struct f_gether *func_to_geth(struct usb_function *f)
  75 {
  76         return container_of(f, struct f_gether, port.func);
  77 }
  78
  79 /*-------------------------------------------------------------------------*/
  80
  81 /*
  82  * "Simple" CDC-subset option is a simple vendor-neutral model that most
  83  * full speed controllers can handle:  one interface, two bulk endpoints.
  84  * To assist host side drivers, we fancy it up a bit, and add descriptors so
  85  * some host side drivers will understand it as a "SAFE" variant.
  86  *
  87  * "SAFE" loosely follows CDC WMC MDLM, violating the spec in various ways.
  88  * Data endpoints live in the control interface, there's no data interface.
  89  * And it's not used to talk to a cell phone radio.
  90  */
  91
  92 /* interface descriptor: */
  93
  94 static struct usb_interface_descriptor subset_data_intf __initdata = {
  95         .bLength =              sizeof subset_data_intf,
  96         .bDescriptorType =      USB_DT_INTERFACE,
  97
  98         /* .bInterfaceNumber = DYNAMIC */
  99         .bAlternateSetting =    0,
 100         .bNumEndpoints =        2,
 101         .bInterfaceClass =      USB_CLASS_COMM,
 102         .bInterfaceSubClass =   USB_CDC_SUBCLASS_MDLM,
 103         .bInterfaceProtocol =   0,
 104         /* .iInterface = DYNAMIC */
 105 };
 106
 107 static struct usb_cdc_header_desc mdlm_header_desc __initdata = {
 108         .bLength =              sizeof mdlm_header_desc,
 109         .bDescriptorType =      USB_DT_CS_INTERFACE,
 110         .bDescriptorSubType =   USB_CDC_HEADER_TYPE,
 111
 112         .bcdCDC =               cpu_to_le16(0x0110),
 113 };
 114
 115 static struct usb_cdc_mdlm_desc mdlm_desc __initdata = {
 116         .bLength =              sizeof mdlm_desc,
 117         .bDescriptorType =      USB_DT_CS_INTERFACE,
 118         .bDescriptorSubType =   USB_CDC_MDLM_TYPE,
 119
 120         .bcdVersion =           cpu_to_le16(0x0100),
 121         .bGUID = {
 122                 0x5d, 0x34, 0xcf, 0x66, 0x11, 0x18, 0x11, 0xd6,
 123                 0xa2, 0x1a, 0x00, 0x01, 0x02, 0xca, 0x9a, 0x7f,
 124         },
 125 };
 126
 127 /* since "usb_cdc_mdlm_detail_desc" is a variable length structure, we
 128  * can't really use its struct.  All we do here is say that we're using
 129  * the submode of "SAFE" which directly matches the CDC Subset.
 130  */
 131 static u8 mdlm_detail_desc[] __initdata = {
 132         6,
 133         USB_DT_CS_INTERFACE,
 134         USB_CDC_MDLM_DETAIL_TYPE,
 135
 136         0,      /* "SAFE" */
 137         0,      /* network control capabilities (none) */
 138         0,      /* network data capabilities ("raw" encapsulation) */
 139 };
 140
 141 static struct usb_cdc_ether_desc ether_desc __initdata = {
 142         .bLength =              sizeof ether_desc,
 143         .bDescriptorType =      USB_DT_CS_INTERFACE,
 144         .bDescriptorSubType =   USB_CDC_ETHERNET_TYPE,
 145
 146         /* this descriptor actually adds value, surprise! */
 147         /* .iMACAddress = DYNAMIC */
 148         .bmEthernetStatistics = cpu_to_le32(0), /* no statistics */
 149         .wMaxSegmentSize =      cpu_to_le16(ETH_FRAME_LEN),
 150         .wNumberMCFilters =     cpu_to_le16(0),
 151         .bNumberPowerFilters =  0,
 152 };
 153
 154 /* full speed support: */
 155
 156 static struct usb_endpoint_descriptor fs_subset_in_desc __initdata = {
 157         .bLength =              USB_DT_ENDPOINT_SIZE,
 158         .bDescriptorType =      USB_DT_ENDPOINT,
 159
 160         .bEndpointAddress =     USB_DIR_IN,
 161         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 162 };
 163
 164 static struct usb_endpoint_descriptor fs_subset_out_desc __initdata = {
 165         .bLength =              USB_DT_ENDPOINT_SIZE,
 166         .bDescriptorType =      USB_DT_ENDPOINT,
 167
 168         .bEndpointAddress =     USB_DIR_OUT,
 169         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 170 };
 171
 172 static struct usb_descriptor_header *fs_eth_function[] __initdata = {
 173         (struct usb_descriptor_header *) &subset_data_intf,
 174         (struct usb_descriptor_header *) &mdlm_header_desc,
 175         (struct usb_descriptor_header *) &mdlm_desc,
 176         (struct usb_descriptor_header *) &mdlm_detail_desc,
 177         (struct usb_descriptor_header *) &ether_desc,
 178         (struct usb_descriptor_header *) &fs_subset_in_desc,
 179         (struct usb_descriptor_header *) &fs_subset_out_desc,
 180         NULL,
 181 };
 182
 183 /* high speed support: */
 184
 185 static struct usb_endpoint_descriptor hs_subset_in_desc __initdata = {
 186         .bLength =              USB_DT_ENDPOINT_SIZE,
 187         .bDescriptorType =      USB_DT_ENDPOINT,
 188
 189         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 190         .wMaxPacketSize =       cpu_to_le16(512),
 191 };
 192
 193 static struct usb_endpoint_descriptor hs_subset_out_desc __initdata = {
 194         .bLength =              USB_DT_ENDPOINT_SIZE,
 195         .bDescriptorType =      USB_DT_ENDPOINT,
 196
 197         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 198         .wMaxPacketSize =       cpu_to_le16(512),
 199 };
 200
 201 static struct usb_descriptor_header *hs_eth_function[] __initdata = {
 202         (struct usb_descriptor_header *) &subset_data_intf,
 203         (struct usb_descriptor_header *) &mdlm_header_desc,
 204         (struct usb_descriptor_header *) &mdlm_desc,
 205         (struct usb_descriptor_header *) &mdlm_detail_desc,
 206         (struct usb_descriptor_header *) &ether_desc,
 207         (struct usb_descriptor_header *) &hs_subset_in_desc,
 208         (struct usb_descriptor_header *) &hs_subset_out_desc,
 209         NULL,
 210 };
 211
 212 /* string descriptors: */
 213
 214 static struct usb_string geth_string_defs[] = {
 215         [0].s = "CDC Ethernet Subset/SAFE",
 216         [1].s = NULL /* DYNAMIC */,
 217         {  } /* end of list */
 218 };
 219
 220 static struct usb_gadget_strings geth_string_table = {
 221         .language =             0x0409, /* en-us */
 222         .strings =              geth_string_defs,
 223 };
 224
 225 static struct usb_gadget_strings *geth_strings[] = {
 226         &geth_string_table,
 227         NULL,
 228 };
 229
 230 /*-------------------------------------------------------------------------*/
 231
 232 static int geth_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 233 {
 234         struct f_gether         *geth = func_to_geth(f);
 235         struct usb_composite_dev *cdev = f->config->cdev;
 236         struct net_device       *net;
 237
 238         /* we know alt == 0, so this is an activation or a reset */
 239
 240         if (geth->port.in_ep->driver_data) {
 241                 DBG(cdev, "reset cdc subset\n");
 242                 gether_disconnect(&geth->port);
 243         }
 244
 245         DBG(cdev, "init + activate cdc subset\n");
 246         geth->port.in = ep_choose(cdev->gadget,
 247                         geth->hs.in, geth->fs.in);
 248         geth->port.out = ep_choose(cdev->gadget,
 249                         geth->hs.out, geth->fs.out);
 250
 251         net = gether_connect(&geth->port);
 252         return IS_ERR(net) ? PTR_ERR(net) : 0;
 253 }
 254
 255 static void geth_disable(struct usb_function *f)
 256 {
 257         struct f_gether *geth = func_to_geth(f);
 258         struct usb_composite_dev *cdev = f->config->cdev;
 259
 260         DBG(cdev, "net deactivated\n");
 261         gether_disconnect(&geth->port);
 262 }
 263
 264 /*-------------------------------------------------------------------------*/
 265
 266 /* serial function driver setup/binding */
 267
 268 static int __init
 269 geth_bind(struct usb_configuration *c, struct usb_function *f)
 270 {
 271         struct usb_composite_dev *cdev = c->cdev;
 272         struct f_gether         *geth = func_to_geth(f);
 273         int                     status;
 274         struct usb_ep           *ep;
 275
 276         /* allocate instance-specific interface IDs */
 277         status = usb_interface_id(c, f);
 278         if (status < 0)
 279                 goto fail;
 280         subset_data_intf.bInterfaceNumber = status;
 281
 282         status = -ENODEV;
 283
 284         /* allocate instance-specific endpoints */
 285         ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_in_desc);
 286         if (!ep)
 287                 goto fail;
 288         geth->port.in_ep = ep;
 289         ep->driver_data = cdev; /* claim */
 290
 291         ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_out_desc);
 292         if (!ep)
 293                 goto fail;
 294         geth->port.out_ep = ep;
 295         ep->driver_data = cdev; /* claim */
 296
 297         /* copy descriptors, and track endpoint copies */
 298         f->descriptors = usb_copy_descriptors(fs_eth_function);
 299
 300         geth->fs.in = usb_find_endpoint(fs_eth_function,
 301                         f->descriptors, &fs_subset_in_desc);
 302         geth->fs.out = usb_find_endpoint(fs_eth_function,
 303                         f->descriptors, &fs_subset_out_desc);
 304
 305
 306         /* support all relevant hardware speeds... we expect that when
 307          * hardware is dual speed, all bulk-capable endpoints work at
 308          * both speeds
 309          */
 310         if (gadget_is_dualspeed(c->cdev->gadget)) {
 311                 hs_subset_in_desc.bEndpointAddress =
 312                                 fs_subset_in_desc.bEndpointAddress;
 313                 hs_subset_out_desc.bEndpointAddress =
 314                                 fs_subset_out_desc.bEndpointAddress;
 315
 316                 /* copy descriptors, and track endpoint copies */
 317                 f->hs_descriptors = usb_copy_descriptors(hs_eth_function);
 318
 319                 geth->hs.in = usb_find_endpoint(hs_eth_function,
 320                                 f->hs_descriptors, &hs_subset_in_desc);
 321                 geth->hs.out = usb_find_endpoint(hs_eth_function,
 322                                 f->hs_descriptors, &hs_subset_out_desc);
 323         }
 324
 325         /* NOTE:  all that is done without knowing or caring about
 326          * the network link ... which is unavailable to this code
 327          * until we're activated via set_alt().
 328          */
 329
 330         DBG(cdev, "CDC Subset: %s speed IN/%s OUT/%s\n",
 331                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 332                         geth->port.in_ep->name, geth->port.out_ep->name);
 333         return 0;
 334
 335 fail:
 336         /* we might as well release our claims on endpoints */
 337         if (geth->port.out)
 338                 geth->port.out_ep->driver_data = NULL;
 339         if (geth->port.in)
 340                 geth->port.in_ep->driver_data = NULL;
 341
 342         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 343
 344         return status;
 345 }
 346
 347 static void
 348 geth_unbind(struct usb_configuration *c, struct usb_function *f)
 349 {
 350         if (gadget_is_dualspeed(c->cdev->gadget))
 351                 usb_free_descriptors(f->hs_descriptors);
 352         usb_free_descriptors(f->descriptors);
 353         geth_string_defs[1].s = NULL;
 354         kfree(func_to_geth(f));
 355 }
 356
 357 /**
 358  * geth_bind_config - add CDC Subset network link to a configuration
 359  * @c: the configuration to support the network link
 360  * @ethaddr: a buffer in which the ethernet address of the host side
 361  *      side of the link was recorded
 362  * Context: single threaded during gadget setup
 363  *
 364  * Returns zero on success, else negative errno.
 365  *
 366  * Caller must have called @gether_setup().  Caller is also responsible
 367  * for calling @gether_cleanup() before module unload.
 368  */
 369 int __init geth_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN])
 370 {
 371         struct f_gether *geth;
 372         int             status;
 373
 374         if (!ethaddr)
 375                 return -EINVAL;
 376
 377         /* maybe allocate device-global string IDs */
 378         if (geth_string_defs[0].id == 0) {
 379
 380                 /* interface label */
 381                 status = usb_string_id(c->cdev);
 382                 if (status < 0)
 383                         return status;
 384                 geth_string_defs[0].id = status;
 385                 subset_data_intf.iInterface = status;
 386
 387                 /* MAC address */
 388                 status = usb_string_id(c->cdev);
 389                 if (status < 0)
 390                         return status;
 391                 geth_string_defs[1].id = status;
 392                 ether_desc.iMACAddress = status;
 393         }
 394
 395         /* allocate and initialize one new instance */
 396         geth = kzalloc(sizeof *geth, GFP_KERNEL);
 397         if (!geth)
 398                 return -ENOMEM;
 399
 400         /* export host's Ethernet address in CDC format */
 401         snprintf(geth->ethaddr, sizeof geth->ethaddr,
 402                 "%02X%02X%02X%02X%02X%02X",
 403                 ethaddr[0], ethaddr[1], ethaddr[2],
 404                 ethaddr[3], ethaddr[4], ethaddr[5]);
 405         geth_string_defs[1].s = geth->ethaddr;
 406
 407         geth->port.cdc_filter = DEFAULT_FILTER;
 408
 409         geth->port.func.name = "cdc_subset";
 410         geth->port.func.strings = geth_strings;
 411         geth->port.func.bind = geth_bind;
 412         geth->port.func.unbind = geth_unbind;
 413         geth->port.func.set_alt = geth_set_alt;
 414         geth->port.func.disable = geth_disable;
 415
 416         status = usb_add_function(c, &geth->port.func);
 417         if (status) {
 418                 geth_string_defs[1].s = NULL;
 419                 kfree(geth);
 420         }
 421         return status;
 422 }