drivers/usb/gadget/ether.c

   1 /*
   2  * ether.c -- Ethernet gadget driver, with CDC and non-CDC options
   3  *
   4  * Copyright (C) 2003-2005,2008 David Brownell
   5  * Copyright (C) 2003-2004 Robert Schwebel, Benedikt Spranger
   6  * Copyright (C) 2008 Nokia Corporation
   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 /* #define VERBOSE_DEBUG */
  24
  25 #include <linux/kernel.h>
  26 #include <linux/utsname.h>
  27
  28
  29 #if defined USB_ETH_RNDIS
  30 #  undef USB_ETH_RNDIS
  31 #endif
  32 #ifdef CONFIG_USB_ETH_RNDIS
  33 #  define USB_ETH_RNDIS y
  34 #endif
  35
  36 #include "u_ether.h"
  37
  38
  39 /*
  40  * Ethernet gadget driver -- with CDC and non-CDC options
  41  * Builds on hardware support for a full duplex link.
  42  *
  43  * CDC Ethernet is the standard USB solution for sending Ethernet frames
  44  * using USB.  Real hardware tends to use the same framing protocol but look
  45  * different for control features.  This driver strongly prefers to use
  46  * this USB-IF standard as its open-systems interoperability solution;
  47  * most host side USB stacks (except from Microsoft) support it.
  48  *
  49  * This is sometimes called "CDC ECM" (Ethernet Control Model) to support
  50  * TLA-soup.  "CDC ACM" (Abstract Control Model) is for modems, and a new
  51  * "CDC EEM" (Ethernet Emulation Model) is starting to spread.
  52  *
  53  * There's some hardware that can't talk CDC ECM.  We make that hardware
  54  * implement a "minimalist" vendor-agnostic CDC core:  same framing, but
  55  * link-level setup only requires activating the configuration.  Only the
  56  * endpoint descriptors, and product/vendor IDs, are relevant; no control
  57  * operations are available.  Linux supports it, but other host operating
  58  * systems may not.  (This is a subset of CDC Ethernet.)
  59  *
  60  * It turns out that if you add a few descriptors to that "CDC Subset",
  61  * (Windows) host side drivers from MCCI can treat it as one submode of
  62  * a proprietary scheme called "SAFE" ... without needing to know about
  63  * specific product/vendor IDs.  So we do that, making it easier to use
  64  * those MS-Windows drivers.  Those added descriptors make it resemble a
  65  * CDC MDLM device, but they don't change device behavior at all.  (See
  66  * MCCI Engineering report 950198 "SAFE Networking Functions".)
  67  *
  68  * A third option is also in use.  Rather than CDC Ethernet, or something
  69  * simpler, Microsoft pushes their own approach: RNDIS.  The published
  70  * RNDIS specs are ambiguous and appear to be incomplete, and are also
  71  * needlessly complex.  They borrow more from CDC ACM than CDC ECM.
  72  */
  73
  74 #define DRIVER_DESC             "Ethernet Gadget"
  75 #define DRIVER_VERSION          "Memorial Day 2008"
  76
  77 #ifdef USB_ETH_RNDIS
  78 #define PREFIX                  "RNDIS/"
  79 #else
  80 #define PREFIX                  ""
  81 #endif
  82
  83 /*
  84  * This driver aims for interoperability by using CDC ECM unless
  85  *
  86  *              can_support_ecm()
  87  *
  88  * returns false, in which case it supports the CDC Subset.  By default,
  89  * that returns true; most hardware has no problems with CDC ECM, that's
  90  * a good default.  Previous versions of this driver had no default; this
  91  * version changes that, removing overhead for new controller support.
  92  *
  93  *      IF YOUR HARDWARE CAN'T SUPPORT CDC ECM, UPDATE THAT ROUTINE!
  94  */
  95
  96 static inline bool has_rndis(void)
  97 {
  98 #ifdef  USB_ETH_RNDIS
  99         return true;
 100 #else
 101         return false;
 102 #endif
 103 }
 104
 105 /*-------------------------------------------------------------------------*/
 106
 107 /*
 108  * Kbuild is not very cooperative with respect to linking separately
 109  * compiled library objects into one module.  So for now we won't use
 110  * separate compilation ... ensuring init/exit sections work to shrink
 111  * the runtime footprint, and giving us at least some parts of what
 112  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
 113  */
 114 #include "composite.c"
 115 #include "usbstring.c"
 116 #include "config.c"
 117 #include "epautoconf.c"
 118
 119 #include "f_ecm.c"
 120 #include "f_subset.c"
 121 #ifdef  USB_ETH_RNDIS
 122 #include "f_rndis.c"
 123 #include "rndis.c"
 124 #endif
 125 #include "f_eem.c"
 126 #include "u_ether.c"
 127
 128 /*-------------------------------------------------------------------------*/
 129
 130 /* DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
 131  * Instead:  allocate your own, using normal USB-IF procedures.
 132  */
 133
 134 /* Thanks to NetChip Technologies for donating this product ID.
 135  * It's for devices with only CDC Ethernet configurations.
 136  */
 137 #define CDC_VENDOR_NUM          0x0525  /* NetChip */
 138 #define CDC_PRODUCT_NUM         0xa4a1  /* Linux-USB Ethernet Gadget */
 139
 140 /* For hardware that can't talk CDC, we use the same vendor ID that
 141  * ARM Linux has used for ethernet-over-usb, both with sa1100 and
 142  * with pxa250.  We're protocol-compatible, if the host-side drivers
 143  * use the endpoint descriptors.  bcdDevice (version) is nonzero, so
 144  * drivers that need to hard-wire endpoint numbers have a hook.
 145  *
 146  * The protocol is a minimal subset of CDC Ether, which works on any bulk
 147  * hardware that's not deeply broken ... even on hardware that can't talk
 148  * RNDIS (like SA-1100, with no interrupt endpoint, or anything that
 149  * doesn't handle control-OUT).
 150  */
 151 #define SIMPLE_VENDOR_NUM       0x049f
 152 #define SIMPLE_PRODUCT_NUM      0x505a
 153
 154 /* For hardware that can talk RNDIS and either of the above protocols,
 155  * use this ID ... the windows INF files will know it.  Unless it's
 156  * used with CDC Ethernet, Linux 2.4 hosts will need updates to choose
 157  * the non-RNDIS configuration.
 158  */
 159 #define RNDIS_VENDOR_NUM        0x0525  /* NetChip */
 160 #define RNDIS_PRODUCT_NUM       0xa4a2  /* Ethernet/RNDIS Gadget */
 161
 162 /* For EEM gadgets */
 163 #define EEM_VENDOR_NUM          0x1d6b  /* Linux Foundation */
 164 #define EEM_PRODUCT_NUM         0x0102  /* EEM Gadget */
 165
 166 /*-------------------------------------------------------------------------*/
 167
 168 static struct usb_device_descriptor device_desc = {
 169         .bLength =              sizeof device_desc,
 170         .bDescriptorType =      USB_DT_DEVICE,
 171
 172         .bcdUSB =               cpu_to_le16 (0x0200),
 173
 174         .bDeviceClass =         USB_CLASS_COMM,
 175         .bDeviceSubClass =      0,
 176         .bDeviceProtocol =      0,
 177         /* .bMaxPacketSize0 = f(hardware) */
 178
 179         /* Vendor and product id defaults change according to what configs
 180          * we support.  (As does bNumConfigurations.)  These values can
 181          * also be overridden by module parameters.
 182          */
 183         .idVendor =             cpu_to_le16 (CDC_VENDOR_NUM),
 184         .idProduct =            cpu_to_le16 (CDC_PRODUCT_NUM),
 185         /* .bcdDevice = f(hardware) */
 186         /* .iManufacturer = DYNAMIC */
 187         /* .iProduct = DYNAMIC */
 188         /* NO SERIAL NUMBER */
 189         .bNumConfigurations =   1,
 190 };
 191
 192 static struct usb_otg_descriptor otg_descriptor = {
 193         .bLength =              sizeof otg_descriptor,
 194         .bDescriptorType =      USB_DT_OTG,
 195
 196         /* REVISIT SRP-only hardware is possible, although
 197          * it would not be called "OTG" ...
 198          */
 199         .bmAttributes =         USB_OTG_SRP | USB_OTG_HNP,
 200 };
 201
 202 static const struct usb_descriptor_header *otg_desc[] = {
 203         (struct usb_descriptor_header *) &otg_descriptor,
 204         NULL,
 205 };
 206
 207
 208 /* string IDs are assigned dynamically */
 209
 210 #define STRING_MANUFACTURER_IDX         0
 211 #define STRING_PRODUCT_IDX              1
 212
 213 static char manufacturer[50];
 214
 215 static struct usb_string strings_dev[] = {
 216         [STRING_MANUFACTURER_IDX].s = manufacturer,
 217         [STRING_PRODUCT_IDX].s = PREFIX DRIVER_DESC,
 218         {  } /* end of list */
 219 };
 220
 221 static struct usb_gadget_strings stringtab_dev = {
 222         .language       = 0x0409,       /* en-us */
 223         .strings        = strings_dev,
 224 };
 225
 226 static struct usb_gadget_strings *dev_strings[] = {
 227         &stringtab_dev,
 228         NULL,
 229 };
 230
 231 static u8 hostaddr[ETH_ALEN];
 232
 233 /*-------------------------------------------------------------------------*/
 234
 235 /*
 236  * We may not have an RNDIS configuration, but if we do it needs to be
 237  * the first one present.  That's to make Microsoft's drivers happy,
 238  * and to follow DOCSIS 1.0 (cable modem standard).
 239  */
 240 static int __init rndis_do_config(struct usb_configuration *c)
 241 {
 242         /* FIXME alloc iConfiguration string, set it in c->strings */
 243
 244         if (gadget_is_otg(c->cdev->gadget)) {
 245                 c->descriptors = otg_desc;
 246                 c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 247         }
 248
 249         return rndis_bind_config(c, hostaddr);
 250 }
 251
 252 static struct usb_configuration rndis_config_driver = {
 253         .label                  = "RNDIS",
 254         .bConfigurationValue    = 2,
 255         /* .iConfiguration = DYNAMIC */
 256         .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
 257 };
 258
 259 /*-------------------------------------------------------------------------*/
 260
 261 #ifdef CONFIG_USB_ETH_EEM
 262 static int use_eem = 1;
 263 #else
 264 static int use_eem;
 265 #endif
 266 module_param(use_eem, bool, 0);
 267 MODULE_PARM_DESC(use_eem, "use CDC EEM mode");
 268
 269 /*
 270  * We _always_ have an ECM, CDC Subset, or EEM configuration.
 271  */
 272 static int __init eth_do_config(struct usb_configuration *c)
 273 {
 274         /* FIXME alloc iConfiguration string, set it in c->strings */
 275
 276         if (gadget_is_otg(c->cdev->gadget)) {
 277                 c->descriptors = otg_desc;
 278                 c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 279         }
 280
 281         if (use_eem)
 282                 return eem_bind_config(c);
 283         else if (can_support_ecm(c->cdev->gadget))
 284                 return ecm_bind_config(c, hostaddr);
 285         else
 286                 return geth_bind_config(c, hostaddr);
 287 }
 288
 289 static struct usb_configuration eth_config_driver = {
 290         /* .label = f(hardware) */
 291         .bConfigurationValue    = 1,
 292         /* .iConfiguration = DYNAMIC */
 293         .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
 294 };
 295
 296 /*-------------------------------------------------------------------------*/
 297
 298 static int __init eth_bind(struct usb_composite_dev *cdev)
 299 {
 300         int                     gcnum;
 301         struct usb_gadget       *gadget = cdev->gadget;
 302         int                     status;
 303
 304         /* set up network link layer */
 305         status = gether_setup(cdev->gadget, hostaddr);
 306         if (status < 0)
 307                 return status;
 308
 309         /* set up main config label and device descriptor */
 310         if (use_eem) {
 311                 /* EEM */
 312                 eth_config_driver.label = "CDC Ethernet (EEM)";
 313                 device_desc.idVendor = cpu_to_le16(EEM_VENDOR_NUM);
 314                 device_desc.idProduct = cpu_to_le16(EEM_PRODUCT_NUM);
 315         } else if (can_support_ecm(cdev->gadget)) {
 316                 /* ECM */
 317                 eth_config_driver.label = "CDC Ethernet (ECM)";
 318         } else {
 319                 /* CDC Subset */
 320                 eth_config_driver.label = "CDC Subset/SAFE";
 321
 322                 device_desc.idVendor = cpu_to_le16(SIMPLE_VENDOR_NUM);
 323                 device_desc.idProduct = cpu_to_le16(SIMPLE_PRODUCT_NUM);
 324                 if (!has_rndis())
 325                         device_desc.bDeviceClass = USB_CLASS_VENDOR_SPEC;
 326         }
 327
 328         if (has_rndis()) {
 329                 /* RNDIS plus ECM-or-Subset */
 330                 device_desc.idVendor = cpu_to_le16(RNDIS_VENDOR_NUM);
 331                 device_desc.idProduct = cpu_to_le16(RNDIS_PRODUCT_NUM);
 332                 device_desc.bNumConfigurations = 2;
 333         }
 334
 335         gcnum = usb_gadget_controller_number(gadget);
 336         if (gcnum >= 0)
 337                 device_desc.bcdDevice = cpu_to_le16(0x0300 | gcnum);
 338         else {
 339                 /* We assume that can_support_ecm() tells the truth;
 340                  * but if the controller isn't recognized at all then
 341                  * that assumption is a bit more likely to be wrong.
 342                  */
 343                 dev_warn(&gadget->dev,
 344                                 "controller '%s' not recognized; trying %s\n",
 345                                 gadget->name,
 346                                 eth_config_driver.label);
 347                 device_desc.bcdDevice =
 348                         cpu_to_le16(0x0300 | 0x0099);
 349         }
 350
 351
 352         /* Allocate string descriptor numbers ... note that string
 353          * contents can be overridden by the composite_dev glue.
 354          */
 355
 356         /* device descriptor strings: manufacturer, product */
 357         snprintf(manufacturer, sizeof manufacturer, "%s %s with %s",
 358                 init_utsname()->sysname, init_utsname()->release,
 359                 gadget->name);
 360         status = usb_string_id(cdev);
 361         if (status < 0)
 362                 goto fail;
 363         strings_dev[STRING_MANUFACTURER_IDX].id = status;
 364         device_desc.iManufacturer = status;
 365
 366         status = usb_string_id(cdev);
 367         if (status < 0)
 368                 goto fail;
 369         strings_dev[STRING_PRODUCT_IDX].id = status;
 370         device_desc.iProduct = status;
 371
 372         /* register our configuration(s); RNDIS first, if it's used */
 373         if (has_rndis()) {
 374                 status = usb_add_config(cdev, &rndis_config_driver,
 375                                 rndis_do_config);
 376                 if (status < 0)
 377                         goto fail;
 378         }
 379
 380         status = usb_add_config(cdev, &eth_config_driver, eth_do_config);
 381         if (status < 0)
 382                 goto fail;
 383
 384         dev_info(&gadget->dev, "%s, version: " DRIVER_VERSION "\n",
 385                         DRIVER_DESC);
 386
 387         return 0;
 388
 389 fail:
 390         gether_cleanup();
 391         return status;
 392 }
 393
 394 static int __exit eth_unbind(struct usb_composite_dev *cdev)
 395 {
 396         gether_cleanup();
 397         return 0;
 398 }
 399
 400 static struct usb_composite_driver eth_driver = {
 401         .name           = "g_ether",
 402         .dev            = &device_desc,
 403         .strings        = dev_strings,
 404         .unbind         = __exit_p(eth_unbind),
 405 };
 406
 407 MODULE_DESCRIPTION(PREFIX DRIVER_DESC);
 408 MODULE_AUTHOR("David Brownell, Benedikt Spanger");
 409 MODULE_LICENSE("GPL");
 410
 411 static int __init init(void)
 412 {
 413         return usb_composite_probe(&eth_driver, eth_bind);
 414 }
 415 module_init(init);
 416
 417 static void __exit cleanup(void)
 418 {
 419         usb_composite_unregister(&eth_driver);
 420 }
 421 module_exit(cleanup);