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 "u_ether.c"
 118
 119 /*-------------------------------------------------------------------------*/
 120
 121 /* DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
 122  * Instead:  allocate your own, using normal USB-IF procedures.
 123  */
 124
 125 /* Thanks to NetChip Technologies for donating this product ID.
 126  * It's for devices with only CDC Ethernet configurations.
 127  */
 128 #define CDC_VENDOR_NUM          0x0525  /* NetChip */
 129 #define CDC_PRODUCT_NUM         0xa4a1  /* Linux-USB Ethernet Gadget */
 130
 131 /* For hardware that can't talk CDC, we use the same vendor ID that
 132  * ARM Linux has used for ethernet-over-usb, both with sa1100 and
 133  * with pxa250.  We're protocol-compatible, if the host-side drivers
 134  * use the endpoint descriptors.  bcdDevice (version) is nonzero, so
 135  * drivers that need to hard-wire endpoint numbers have a hook.
 136  *
 137  * The protocol is a minimal subset of CDC Ether, which works on any bulk
 138  * hardware that's not deeply broken ... even on hardware that can't talk
 139  * RNDIS (like SA-1100, with no interrupt endpoint, or anything that
 140  * doesn't handle control-OUT).
 141  */
 142 #define SIMPLE_VENDOR_NUM       0x049f
 143 #define SIMPLE_PRODUCT_NUM      0x505a
 144
 145 /* For hardware that can talk RNDIS and either of the above protocols,
 146  * use this ID ... the windows INF files will know it.  Unless it's
 147  * used with CDC Ethernet, Linux 2.4 hosts will need updates to choose
 148  * the non-RNDIS configuration.
 149  */
 150 #define RNDIS_VENDOR_NUM        0x0525  /* NetChip */
 151 #define RNDIS_PRODUCT_NUM       0xa4a2  /* Ethernet/RNDIS Gadget */
 152
 153 /*-------------------------------------------------------------------------*/
 154
 155 static struct usb_device_descriptor device_desc = {
 156         .bLength =              sizeof device_desc,
 157         .bDescriptorType =      USB_DT_DEVICE,
 158
 159         .bcdUSB =               cpu_to_le16 (0x0200),
 160
 161         .bDeviceClass =         USB_CLASS_COMM,
 162         .bDeviceSubClass =      0,
 163         .bDeviceProtocol =      0,
 164         /* .bMaxPacketSize0 = f(hardware) */
 165
 166         /* Vendor and product id defaults change according to what configs
 167          * we support.  (As does bNumConfigurations.)  These values can
 168          * also be overridden by module parameters.
 169          */
 170         .idVendor =             cpu_to_le16 (CDC_VENDOR_NUM),
 171         .idProduct =            cpu_to_le16 (CDC_PRODUCT_NUM),
 172         /* .bcdDevice = f(hardware) */
 173         /* .iManufacturer = DYNAMIC */
 174         /* .iProduct = DYNAMIC */
 175         /* NO SERIAL NUMBER */
 176         .bNumConfigurations =   1,
 177 };
 178
 179 static struct usb_otg_descriptor otg_descriptor = {
 180         .bLength =              sizeof otg_descriptor,
 181         .bDescriptorType =      USB_DT_OTG,
 182
 183         /* REVISIT SRP-only hardware is possible, although
 184          * it would not be called "OTG" ...
 185          */
 186         .bmAttributes =         USB_OTG_SRP | USB_OTG_HNP,
 187 };
 188
 189 static const struct usb_descriptor_header *otg_desc[] = {
 190         (struct usb_descriptor_header *) &otg_descriptor,
 191         NULL,
 192 };
 193
 194
 195 /* string IDs are assigned dynamically */
 196
 197 #define STRING_MANUFACTURER_IDX         0
 198 #define STRING_PRODUCT_IDX              1
 199
 200 static char manufacturer[50];
 201
 202 static struct usb_string strings_dev[] = {
 203         [STRING_MANUFACTURER_IDX].s = manufacturer,
 204         [STRING_PRODUCT_IDX].s = PREFIX DRIVER_DESC,
 205         {  } /* end of list */
 206 };
 207
 208 static struct usb_gadget_strings stringtab_dev = {
 209         .language       = 0x0409,       /* en-us */
 210         .strings        = strings_dev,
 211 };
 212
 213 static struct usb_gadget_strings *dev_strings[] = {
 214         &stringtab_dev,
 215         NULL,
 216 };
 217
 218 static u8 hostaddr[ETH_ALEN];
 219
 220 /*-------------------------------------------------------------------------*/
 221
 222 /*
 223  * We may not have an RNDIS configuration, but if we do it needs to be
 224  * the first one present.  That's to make Microsoft's drivers happy,
 225  * and to follow DOCSIS 1.0 (cable modem standard).
 226  */
 227 static int __init rndis_do_config(struct usb_configuration *c)
 228 {
 229         /* FIXME alloc iConfiguration string, set it in c->strings */
 230
 231         if (gadget_is_otg(c->cdev->gadget)) {
 232                 c->descriptors = otg_desc;
 233                 c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 234         }
 235
 236         return rndis_bind_config(c, hostaddr);
 237 }
 238
 239 static struct usb_configuration rndis_config_driver = {
 240         .label                  = "RNDIS",
 241         .bind                   = rndis_do_config,
 242         .bConfigurationValue    = 2,
 243         /* .iConfiguration = DYNAMIC */
 244         .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
 245 };
 246
 247 /*-------------------------------------------------------------------------*/
 248
 249 /*
 250  * We _always_ have an ECM or CDC Subset configuration.
 251  */
 252 static int __init eth_do_config(struct usb_configuration *c)
 253 {
 254         /* FIXME alloc iConfiguration string, set it in c->strings */
 255
 256         if (gadget_is_otg(c->cdev->gadget)) {
 257                 c->descriptors = otg_desc;
 258                 c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 259         }
 260
 261         if (can_support_ecm(c->cdev->gadget))
 262                 return ecm_bind_config(c, hostaddr);
 263         else
 264                 return geth_bind_config(c, hostaddr);
 265 }
 266
 267 static struct usb_configuration eth_config_driver = {
 268         /* .label = f(hardware) */
 269         .bind                   = eth_do_config,
 270         .bConfigurationValue    = 1,
 271         /* .iConfiguration = DYNAMIC */
 272         .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
 273 };
 274
 275 /*-------------------------------------------------------------------------*/
 276
 277 static int __init eth_bind(struct usb_composite_dev *cdev)
 278 {
 279         int                     gcnum;
 280         struct usb_gadget       *gadget = cdev->gadget;
 281         int                     status;
 282
 283         /* set up network link layer */
 284         status = gether_setup(cdev->gadget, hostaddr);
 285         if (status < 0)
 286                 return status;
 287
 288         /* set up main config label and device descriptor */
 289         if (can_support_ecm(cdev->gadget)) {
 290                 /* ECM */
 291                 eth_config_driver.label = "CDC Ethernet (ECM)";
 292         } else {
 293                 /* CDC Subset */
 294                 eth_config_driver.label = "CDC Subset/SAFE";
 295
 296                 device_desc.idVendor = cpu_to_le16(SIMPLE_VENDOR_NUM);
 297                 device_desc.idProduct = cpu_to_le16(SIMPLE_PRODUCT_NUM);
 298                 if (!has_rndis())
 299                         device_desc.bDeviceClass = USB_CLASS_VENDOR_SPEC;
 300         }
 301
 302         if (has_rndis()) {
 303                 /* RNDIS plus ECM-or-Subset */
 304                 device_desc.idVendor = cpu_to_le16(RNDIS_VENDOR_NUM);
 305                 device_desc.idProduct = cpu_to_le16(RNDIS_PRODUCT_NUM);
 306                 device_desc.bNumConfigurations = 2;
 307         }
 308
 309         gcnum = usb_gadget_controller_number(gadget);
 310         if (gcnum >= 0)
 311                 device_desc.bcdDevice = cpu_to_le16(0x0300 | gcnum);
 312         else {
 313                 /* We assume that can_support_ecm() tells the truth;
 314                  * but if the controller isn't recognized at all then
 315                  * that assumption is a bit more likely to be wrong.
 316                  */
 317                 dev_warn(&gadget->dev,
 318                                 "controller '%s' not recognized; trying %s\n",
 319                                 gadget->name,
 320                                 eth_config_driver.label);
 321                 device_desc.bcdDevice =
 322                         cpu_to_le16(0x0300 | 0x0099);
 323         }
 324
 325
 326         /* Allocate string descriptor numbers ... note that string
 327          * contents can be overridden by the composite_dev glue.
 328          */
 329
 330         /* device descriptor strings: manufacturer, product */
 331         snprintf(manufacturer, sizeof manufacturer, "%s %s with %s",
 332                 init_utsname()->sysname, init_utsname()->release,
 333                 gadget->name);
 334         status = usb_string_id(cdev);
 335         if (status < 0)
 336                 goto fail;
 337         strings_dev[STRING_MANUFACTURER_IDX].id = status;
 338         device_desc.iManufacturer = status;
 339
 340         status = usb_string_id(cdev);
 341         if (status < 0)
 342                 goto fail;
 343         strings_dev[STRING_PRODUCT_IDX].id = status;
 344         device_desc.iProduct = status;
 345
 346         /* register our configuration(s); RNDIS first, if it's used */
 347         if (has_rndis()) {
 348                 status = usb_add_config(cdev, &rndis_config_driver);
 349                 if (status < 0)
 350                         goto fail;
 351         }
 352
 353         status = usb_add_config(cdev, &eth_config_driver);
 354         if (status < 0)
 355                 goto fail;
 356
 357         dev_info(&gadget->dev, "%s, version: " DRIVER_VERSION "\n",
 358                         DRIVER_DESC);
 359
 360         return 0;
 361
 362 fail:
 363         gether_cleanup();
 364         return status;
 365 }
 366
 367 static int __exit eth_unbind(struct usb_composite_dev *cdev)
 368 {
 369         gether_cleanup();
 370         return 0;
 371 }
 372
 373 static struct usb_composite_driver eth_driver = {
 374         .name           = "g_ether",
 375         .dev            = &device_desc,
 376         .strings        = dev_strings,
 377         .bind           = eth_bind,
 378         .unbind         = __exit_p(eth_unbind),
 379 };
 380
 381 MODULE_DESCRIPTION(PREFIX DRIVER_DESC);
 382 MODULE_AUTHOR("David Brownell, Benedikt Spanger");
 383 MODULE_LICENSE("GPL");
 384
 385 static int __init init(void)
 386 {
 387         return usb_composite_register(&eth_driver);
 388 }
 389 module_init(init);
 390
 391 static void __exit cleanup(void)
 392 {
 393         usb_composite_unregister(&eth_driver);
 394 }
 395 module_exit(cleanup);