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