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