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