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/slab.h>
  23 #include <linux/kernel.h>
  24 #include <linux/device.h>
  25 #include <linux/etherdevice.h>
  26
  27 #include "u_ether.h"
  28
  29
  30 /*
  31  * This function packages a simple "CDC Subset" Ethernet port with no real
  32  * control mechanisms; just raw data transfer over two bulk endpoints.
  33  * The data transfer model is exactly that of CDC Ethernet, which is
  34  * why we call it the "CDC Subset".
  35  *
  36  * Because it's not standardized, this has some interoperability issues.
  37  * They mostly relate to driver binding, since the data transfer model is
  38  * so simple (CDC Ethernet).  The original versions of this protocol used
  39  * specific product/vendor IDs:  byteswapped IDs for Digital Equipment's
  40  * SA-1100 "Itsy" board, which could run Linux 2.4 kernels and supported
  41  * daughtercards with USB peripheral connectors.  (It was used more often
  42  * with other boards, using the Itsy identifiers.)  Linux hosts recognized
  43  * this with CONFIG_USB_ARMLINUX; these devices have only one configuration
  44  * and one interface.
  45  *
  46  * At some point, MCCI defined a (nonconformant) CDC MDLM variant called
  47  * "SAFE", which happens to have a mode which is identical to the "CDC
  48  * Subset" in terms of data transfer and lack of control model.  This was
  49  * adopted by later Sharp Zaurus models, and by some other software which
  50  * Linux hosts recognize with CONFIG_USB_NET_ZAURUS.
  51  *
  52  * Because Microsoft's RNDIS drivers are far from robust, we added a few
  53  * descriptors to the CDC Subset code, making this code look like a SAFE
  54  * implementation.  This lets you use MCCI's host side MS-Windows drivers
  55  * if you get fed up with RNDIS.  It also makes it easier for composite
  56  * drivers to work, since they can use class based binding instead of
  57  * caring about specific product and vendor IDs.
  58  */
  59
  60 struct f_gether {
  61         struct gether                   port;
  62
  63         char                            ethaddr[14];
  64 };
  65
  66 static inline struct f_gether *func_to_geth(struct usb_function *f)
  67 {
  68         return container_of(f, struct f_gether, port.func);
  69 }
  70
  71 /*-------------------------------------------------------------------------*/
  72
  73 /*
  74  * "Simple" CDC-subset option is a simple vendor-neutral model that most
  75  * full speed controllers can handle:  one interface, two bulk endpoints.
  76  * To assist host side drivers, we fancy it up a bit, and add descriptors so
  77  * some host side drivers will understand it as a "SAFE" variant.
  78  *
  79  * "SAFE" loosely follows CDC WMC MDLM, violating the spec in various ways.
  80  * Data endpoints live in the control interface, there's no data interface.
  81  * And it's not used to talk to a cell phone radio.
  82  */
  83
  84 /* interface descriptor: */
  85
  86 static struct usb_interface_descriptor subset_data_intf __initdata = {
  87         .bLength =              sizeof subset_data_intf,
  88         .bDescriptorType =      USB_DT_INTERFACE,
  89
  90         /* .bInterfaceNumber = DYNAMIC */
  91         .bAlternateSetting =    0,
  92         .bNumEndpoints =        2,
  93         .bInterfaceClass =      USB_CLASS_COMM,
  94         .bInterfaceSubClass =   USB_CDC_SUBCLASS_MDLM,
  95         .bInterfaceProtocol =   0,
  96         /* .iInterface = DYNAMIC */
  97 };
  98
  99 static struct usb_cdc_header_desc mdlm_header_desc __initdata = {
 100         .bLength =              sizeof mdlm_header_desc,
 101         .bDescriptorType =      USB_DT_CS_INTERFACE,
 102         .bDescriptorSubType =   USB_CDC_HEADER_TYPE,
 103
 104         .bcdCDC =               cpu_to_le16(0x0110),
 105 };
 106
 107 static struct usb_cdc_mdlm_desc mdlm_desc __initdata = {
 108         .bLength =              sizeof mdlm_desc,
 109         .bDescriptorType =      USB_DT_CS_INTERFACE,
 110         .bDescriptorSubType =   USB_CDC_MDLM_TYPE,
 111
 112         .bcdVersion =           cpu_to_le16(0x0100),
 113         .bGUID = {
 114                 0x5d, 0x34, 0xcf, 0x66, 0x11, 0x18, 0x11, 0xd6,
 115                 0xa2, 0x1a, 0x00, 0x01, 0x02, 0xca, 0x9a, 0x7f,
 116         },
 117 };
 118
 119 /* since "usb_cdc_mdlm_detail_desc" is a variable length structure, we
 120  * can't really use its struct.  All we do here is say that we're using
 121  * the submode of "SAFE" which directly matches the CDC Subset.
 122  */
 123 static u8 mdlm_detail_desc[] __initdata = {
 124         6,
 125         USB_DT_CS_INTERFACE,
 126         USB_CDC_MDLM_DETAIL_TYPE,
 127
 128         0,      /* "SAFE" */
 129         0,      /* network control capabilities (none) */
 130         0,      /* network data capabilities ("raw" encapsulation) */
 131 };
 132
 133 static struct usb_cdc_ether_desc ether_desc __initdata = {
 134         .bLength =              sizeof ether_desc,
 135         .bDescriptorType =      USB_DT_CS_INTERFACE,
 136         .bDescriptorSubType =   USB_CDC_ETHERNET_TYPE,
 137
 138         /* this descriptor actually adds value, surprise! */
 139         /* .iMACAddress = DYNAMIC */
 140         .bmEthernetStatistics = cpu_to_le32(0), /* no statistics */
 141         .wMaxSegmentSize =      cpu_to_le16(ETH_FRAME_LEN),
 142         .wNumberMCFilters =     cpu_to_le16(0),
 143         .bNumberPowerFilters =  0,
 144 };
 145
 146 /* full speed support: */
 147
 148 static struct usb_endpoint_descriptor fs_subset_in_desc __initdata = {
 149         .bLength =              USB_DT_ENDPOINT_SIZE,
 150         .bDescriptorType =      USB_DT_ENDPOINT,
 151
 152         .bEndpointAddress =     USB_DIR_IN,
 153         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 154 };
 155
 156 static struct usb_endpoint_descriptor fs_subset_out_desc __initdata = {
 157         .bLength =              USB_DT_ENDPOINT_SIZE,
 158         .bDescriptorType =      USB_DT_ENDPOINT,
 159
 160         .bEndpointAddress =     USB_DIR_OUT,
 161         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 162 };
 163
 164 static struct usb_descriptor_header *fs_eth_function[] __initdata = {
 165         (struct usb_descriptor_header *) &subset_data_intf,
 166         (struct usb_descriptor_header *) &mdlm_header_desc,
 167         (struct usb_descriptor_header *) &mdlm_desc,
 168         (struct usb_descriptor_header *) &mdlm_detail_desc,
 169         (struct usb_descriptor_header *) &ether_desc,
 170         (struct usb_descriptor_header *) &fs_subset_in_desc,
 171         (struct usb_descriptor_header *) &fs_subset_out_desc,
 172         NULL,
 173 };
 174
 175 /* high speed support: */
 176
 177 static struct usb_endpoint_descriptor hs_subset_in_desc __initdata = {
 178         .bLength =              USB_DT_ENDPOINT_SIZE,
 179         .bDescriptorType =      USB_DT_ENDPOINT,
 180
 181         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 182         .wMaxPacketSize =       cpu_to_le16(512),
 183 };
 184
 185 static struct usb_endpoint_descriptor hs_subset_out_desc __initdata = {
 186         .bLength =              USB_DT_ENDPOINT_SIZE,
 187         .bDescriptorType =      USB_DT_ENDPOINT,
 188
 189         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 190         .wMaxPacketSize =       cpu_to_le16(512),
 191 };
 192
 193 static struct usb_descriptor_header *hs_eth_function[] __initdata = {
 194         (struct usb_descriptor_header *) &subset_data_intf,
 195         (struct usb_descriptor_header *) &mdlm_header_desc,
 196         (struct usb_descriptor_header *) &mdlm_desc,
 197         (struct usb_descriptor_header *) &mdlm_detail_desc,
 198         (struct usb_descriptor_header *) &ether_desc,
 199         (struct usb_descriptor_header *) &hs_subset_in_desc,
 200         (struct usb_descriptor_header *) &hs_subset_out_desc,
 201         NULL,
 202 };
 203
 204 /* super speed support: */
 205
 206 static struct usb_endpoint_descriptor ss_subset_in_desc __initdata = {
 207         .bLength =              USB_DT_ENDPOINT_SIZE,
 208         .bDescriptorType =      USB_DT_ENDPOINT,
 209
 210         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 211         .wMaxPacketSize =       cpu_to_le16(1024),
 212 };
 213
 214 static struct usb_endpoint_descriptor ss_subset_out_desc __initdata = {
 215         .bLength =              USB_DT_ENDPOINT_SIZE,
 216         .bDescriptorType =      USB_DT_ENDPOINT,
 217
 218         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 219         .wMaxPacketSize =       cpu_to_le16(1024),
 220 };
 221
 222 static struct usb_ss_ep_comp_descriptor ss_subset_bulk_comp_desc __initdata = {
 223         .bLength =              sizeof ss_subset_bulk_comp_desc,
 224         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 225
 226         /* the following 2 values can be tweaked if necessary */
 227         /* .bMaxBurst =         0, */
 228         /* .bmAttributes =      0, */
 229 };
 230
 231 static struct usb_descriptor_header *ss_eth_function[] __initdata = {
 232         (struct usb_descriptor_header *) &subset_data_intf,
 233         (struct usb_descriptor_header *) &mdlm_header_desc,
 234         (struct usb_descriptor_header *) &mdlm_desc,
 235         (struct usb_descriptor_header *) &mdlm_detail_desc,
 236         (struct usb_descriptor_header *) &ether_desc,
 237         (struct usb_descriptor_header *) &ss_subset_in_desc,
 238         (struct usb_descriptor_header *) &ss_subset_bulk_comp_desc,
 239         (struct usb_descriptor_header *) &ss_subset_out_desc,
 240         (struct usb_descriptor_header *) &ss_subset_bulk_comp_desc,
 241         NULL,
 242 };
 243
 244 /* string descriptors: */
 245
 246 static struct usb_string geth_string_defs[] = {
 247         [0].s = "CDC Ethernet Subset/SAFE",
 248         [1].s = NULL /* DYNAMIC */,
 249         {  } /* end of list */
 250 };
 251
 252 static struct usb_gadget_strings geth_string_table = {
 253         .language =             0x0409, /* en-us */
 254         .strings =              geth_string_defs,
 255 };
 256
 257 static struct usb_gadget_strings *geth_strings[] = {
 258         &geth_string_table,
 259         NULL,
 260 };
 261
 262 /*-------------------------------------------------------------------------*/
 263
 264 static int geth_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 265 {
 266         struct f_gether         *geth = func_to_geth(f);
 267         struct usb_composite_dev *cdev = f->config->cdev;
 268         struct net_device       *net;
 269
 270         /* we know alt == 0, so this is an activation or a reset */
 271
 272         if (geth->port.in_ep->driver_data) {
 273                 DBG(cdev, "reset cdc subset\n");
 274                 gether_disconnect(&geth->port);
 275         }
 276
 277         DBG(cdev, "init + activate cdc subset\n");
 278         if (config_ep_by_speed(cdev->gadget, f, geth->port.in_ep) ||
 279             config_ep_by_speed(cdev->gadget, f, geth->port.out_ep)) {
 280                 geth->port.in_ep->desc = NULL;
 281                 geth->port.out_ep->desc = NULL;
 282                 return -EINVAL;
 283         }
 284
 285         net = gether_connect(&geth->port);
 286         return IS_ERR(net) ? PTR_ERR(net) : 0;
 287 }
 288
 289 static void geth_disable(struct usb_function *f)
 290 {
 291         struct f_gether *geth = func_to_geth(f);
 292         struct usb_composite_dev *cdev = f->config->cdev;
 293
 294         DBG(cdev, "net deactivated\n");
 295         gether_disconnect(&geth->port);
 296 }
 297
 298 /*-------------------------------------------------------------------------*/
 299
 300 /* serial function driver setup/binding */
 301
 302 static int __init
 303 geth_bind(struct usb_configuration *c, struct usb_function *f)
 304 {
 305         struct usb_composite_dev *cdev = c->cdev;
 306         struct f_gether         *geth = func_to_geth(f);
 307         int                     status;
 308         struct usb_ep           *ep;
 309
 310         /* allocate instance-specific interface IDs */
 311         status = usb_interface_id(c, f);
 312         if (status < 0)
 313                 goto fail;
 314         subset_data_intf.bInterfaceNumber = status;
 315
 316         status = -ENODEV;
 317
 318         /* allocate instance-specific endpoints */
 319         ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_in_desc);
 320         if (!ep)
 321                 goto fail;
 322         geth->port.in_ep = ep;
 323         ep->driver_data = cdev; /* claim */
 324
 325         ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_out_desc);
 326         if (!ep)
 327                 goto fail;
 328         geth->port.out_ep = ep;
 329         ep->driver_data = cdev; /* claim */
 330
 331         /* copy descriptors, and track endpoint copies */
 332         f->descriptors = usb_copy_descriptors(fs_eth_function);
 333         if (!f->descriptors)
 334                 goto fail;
 335
 336         /* support all relevant hardware speeds... we expect that when
 337          * hardware is dual speed, all bulk-capable endpoints work at
 338          * both speeds
 339          */
 340         if (gadget_is_dualspeed(c->cdev->gadget)) {
 341                 hs_subset_in_desc.bEndpointAddress =
 342                                 fs_subset_in_desc.bEndpointAddress;
 343                 hs_subset_out_desc.bEndpointAddress =
 344                                 fs_subset_out_desc.bEndpointAddress;
 345
 346                 /* copy descriptors, and track endpoint copies */
 347                 f->hs_descriptors = usb_copy_descriptors(hs_eth_function);
 348                 if (!f->hs_descriptors)
 349                         goto fail;
 350         }
 351
 352         if (gadget_is_superspeed(c->cdev->gadget)) {
 353                 ss_subset_in_desc.bEndpointAddress =
 354                                 fs_subset_in_desc.bEndpointAddress;
 355                 ss_subset_out_desc.bEndpointAddress =
 356                                 fs_subset_out_desc.bEndpointAddress;
 357
 358                 /* copy descriptors, and track endpoint copies */
 359                 f->ss_descriptors = usb_copy_descriptors(ss_eth_function);
 360                 if (!f->ss_descriptors)
 361                         goto fail;
 362         }
 363
 364         /* NOTE:  all that is done without knowing or caring about
 365          * the network link ... which is unavailable to this code
 366          * until we're activated via set_alt().
 367          */
 368
 369         DBG(cdev, "CDC Subset: %s speed IN/%s OUT/%s\n",
 370                         gadget_is_superspeed(c->cdev->gadget) ? "super" :
 371                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 372                         geth->port.in_ep->name, geth->port.out_ep->name);
 373         return 0;
 374
 375 fail:
 376         if (f->descriptors)
 377                 usb_free_descriptors(f->descriptors);
 378         if (f->hs_descriptors)
 379                 usb_free_descriptors(f->hs_descriptors);
 380
 381         /* we might as well release our claims on endpoints */
 382         if (geth->port.out_ep->desc)
 383                 geth->port.out_ep->driver_data = NULL;
 384         if (geth->port.in_ep->desc)
 385                 geth->port.in_ep->driver_data = NULL;
 386
 387         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 388
 389         return status;
 390 }
 391
 392 static void
 393 geth_unbind(struct usb_configuration *c, struct usb_function *f)
 394 {
 395         if (gadget_is_superspeed(c->cdev->gadget))
 396                 usb_free_descriptors(f->ss_descriptors);
 397         if (gadget_is_dualspeed(c->cdev->gadget))
 398                 usb_free_descriptors(f->hs_descriptors);
 399         usb_free_descriptors(f->descriptors);
 400         geth_string_defs[1].s = NULL;
 401         kfree(func_to_geth(f));
 402 }
 403
 404 /**
 405  * geth_bind_config - add CDC Subset network link to a configuration
 406  * @c: the configuration to support the network link
 407  * @ethaddr: a buffer in which the ethernet address of the host side
 408  *      side of the link was recorded
 409  * Context: single threaded during gadget setup
 410  *
 411  * Returns zero on success, else negative errno.
 412  *
 413  * Caller must have called @gether_setup().  Caller is also responsible
 414  * for calling @gether_cleanup() before module unload.
 415  */
 416 int __init geth_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN])
 417 {
 418         struct f_gether *geth;
 419         int             status;
 420
 421         if (!ethaddr)
 422                 return -EINVAL;
 423
 424         /* maybe allocate device-global string IDs */
 425         if (geth_string_defs[0].id == 0) {
 426
 427                 /* interface label */
 428                 status = usb_string_id(c->cdev);
 429                 if (status < 0)
 430                         return status;
 431                 geth_string_defs[0].id = status;
 432                 subset_data_intf.iInterface = status;
 433
 434                 /* MAC address */
 435                 status = usb_string_id(c->cdev);
 436                 if (status < 0)
 437                         return status;
 438                 geth_string_defs[1].id = status;
 439                 ether_desc.iMACAddress = status;
 440         }
 441
 442         /* allocate and initialize one new instance */
 443         geth = kzalloc(sizeof *geth, GFP_KERNEL);
 444         if (!geth)
 445                 return -ENOMEM;
 446
 447         /* export host's Ethernet address in CDC format */
 448         snprintf(geth->ethaddr, sizeof geth->ethaddr,
 449                 "%02X%02X%02X%02X%02X%02X",
 450                 ethaddr[0], ethaddr[1], ethaddr[2],
 451                 ethaddr[3], ethaddr[4], ethaddr[5]);
 452         geth_string_defs[1].s = geth->ethaddr;
 453
 454         geth->port.cdc_filter = DEFAULT_FILTER;
 455
 456         geth->port.func.name = "cdc_subset";
 457         geth->port.func.strings = geth_strings;
 458         geth->port.func.bind = geth_bind;
 459         geth->port.func.unbind = geth_unbind;
 460         geth->port.func.set_alt = geth_set_alt;
 461         geth->port.func.disable = geth_disable;
 462
 463         status = usb_add_function(c, &geth->port.func);
 464         if (status) {
 465                 geth_string_defs[1].s = NULL;
 466                 kfree(geth);
 467         }
 468         return status;
 469 }