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 13 #include <linux/slab.h> 14 #include <linux/kernel.h> 15 #include <linux/module.h> 16 #include <linux/device.h> 17 #include <linux/etherdevice.h> 18 19 #include "u_ether.h" 20 #include "u_ether_configfs.h" 21 #include "u_gether.h" 22 23 /* 24 * This function packages a simple "CDC Subset" Ethernet port with no real 25 * control mechanisms; just raw data transfer over two bulk endpoints. 26 * The data transfer model is exactly that of CDC Ethernet, which is 27 * why we call it the "CDC Subset". 28 * 29 * Because it's not standardized, this has some interoperability issues. 30 * They mostly relate to driver binding, since the data transfer model is 31 * so simple (CDC Ethernet). The original versions of this protocol used 32 * specific product/vendor IDs: byteswapped IDs for Digital Equipment's 33 * SA-1100 "Itsy" board, which could run Linux 2.4 kernels and supported 34 * daughtercards with USB peripheral connectors. (It was used more often 35 * with other boards, using the Itsy identifiers.) Linux hosts recognized 36 * this with CONFIG_USB_ARMLINUX; these devices have only one configuration 37 * and one interface. 38 * 39 * At some point, MCCI defined a (nonconformant) CDC MDLM variant called 40 * "SAFE", which happens to have a mode which is identical to the "CDC 41 * Subset" in terms of data transfer and lack of control model. This was 42 * adopted by later Sharp Zaurus models, and by some other software which 43 * Linux hosts recognize with CONFIG_USB_NET_ZAURUS. 44 * 45 * Because Microsoft's RNDIS drivers are far from robust, we added a few 46 * descriptors to the CDC Subset code, making this code look like a SAFE 47 * implementation. This lets you use MCCI's host side MS-Windows drivers 48 * if you get fed up with RNDIS. It also makes it easier for composite 49 * drivers to work, since they can use class based binding instead of 50 * caring about specific product and vendor IDs. 51 */ 52 53 struct f_gether { 54 struct gether port; 55 56 char ethaddr[14]; 57 }; 58 59 static inline struct f_gether *func_to_geth(struct usb_function *f) 60 { 61 return container_of(f, struct f_gether, port.func); 62 } 63 64 /*-------------------------------------------------------------------------*/ 65 66 /* 67 * "Simple" CDC-subset option is a simple vendor-neutral model that most 68 * full speed controllers can handle: one interface, two bulk endpoints. 69 * To assist host side drivers, we fancy it up a bit, and add descriptors so 70 * some host side drivers will understand it as a "SAFE" variant. 71 * 72 * "SAFE" loosely follows CDC WMC MDLM, violating the spec in various ways. 73 * Data endpoints live in the control interface, there's no data interface. 74 * And it's not used to talk to a cell phone radio. 75 */ 76 77 /* interface descriptor: */ 78 79 static struct usb_interface_descriptor subset_data_intf = { 80 .bLength = sizeof subset_data_intf, 81 .bDescriptorType = USB_DT_INTERFACE, 82 83 /* .bInterfaceNumber = DYNAMIC */ 84 .bAlternateSetting = 0, 85 .bNumEndpoints = 2, 86 .bInterfaceClass = USB_CLASS_COMM, 87 .bInterfaceSubClass = USB_CDC_SUBCLASS_MDLM, 88 .bInterfaceProtocol = 0, 89 /* .iInterface = DYNAMIC */ 90 }; 91 92 static struct usb_cdc_header_desc mdlm_header_desc = { 93 .bLength = sizeof mdlm_header_desc, 94 .bDescriptorType = USB_DT_CS_INTERFACE, 95 .bDescriptorSubType = USB_CDC_HEADER_TYPE, 96 97 .bcdCDC = cpu_to_le16(0x0110), 98 }; 99 100 static struct usb_cdc_mdlm_desc mdlm_desc = { 101 .bLength = sizeof mdlm_desc, 102 .bDescriptorType = USB_DT_CS_INTERFACE, 103 .bDescriptorSubType = USB_CDC_MDLM_TYPE, 104 105 .bcdVersion = cpu_to_le16(0x0100), 106 .bGUID = { 107 0x5d, 0x34, 0xcf, 0x66, 0x11, 0x18, 0x11, 0xd6, 108 0xa2, 0x1a, 0x00, 0x01, 0x02, 0xca, 0x9a, 0x7f, 109 }, 110 }; 111 112 /* since "usb_cdc_mdlm_detail_desc" is a variable length structure, we 113 * can't really use its struct. All we do here is say that we're using 114 * the submode of "SAFE" which directly matches the CDC Subset. 115 */ 116 static u8 mdlm_detail_desc[] = { 117 6, 118 USB_DT_CS_INTERFACE, 119 USB_CDC_MDLM_DETAIL_TYPE, 120 121 0, /* "SAFE" */ 122 0, /* network control capabilities (none) */ 123 0, /* network data capabilities ("raw" encapsulation) */ 124 }; 125 126 static struct usb_cdc_ether_desc ether_desc = { 127 .bLength = sizeof ether_desc, 128 .bDescriptorType = USB_DT_CS_INTERFACE, 129 .bDescriptorSubType = USB_CDC_ETHERNET_TYPE, 130 131 /* this descriptor actually adds value, surprise! */ 132 /* .iMACAddress = DYNAMIC */ 133 .bmEthernetStatistics = cpu_to_le32(0), /* no statistics */ 134 .wMaxSegmentSize = cpu_to_le16(ETH_FRAME_LEN), 135 .wNumberMCFilters = cpu_to_le16(0), 136 .bNumberPowerFilters = 0, 137 }; 138 139 /* full speed support: */ 140 141 static struct usb_endpoint_descriptor fs_subset_in_desc = { 142 .bLength = USB_DT_ENDPOINT_SIZE, 143 .bDescriptorType = USB_DT_ENDPOINT, 144 145 .bEndpointAddress = USB_DIR_IN, 146 .bmAttributes = USB_ENDPOINT_XFER_BULK, 147 }; 148 149 static struct usb_endpoint_descriptor fs_subset_out_desc = { 150 .bLength = USB_DT_ENDPOINT_SIZE, 151 .bDescriptorType = USB_DT_ENDPOINT, 152 153 .bEndpointAddress = USB_DIR_OUT, 154 .bmAttributes = USB_ENDPOINT_XFER_BULK, 155 }; 156 157 static struct usb_descriptor_header *fs_eth_function[] = { 158 (struct usb_descriptor_header *) &subset_data_intf, 159 (struct usb_descriptor_header *) &mdlm_header_desc, 160 (struct usb_descriptor_header *) &mdlm_desc, 161 (struct usb_descriptor_header *) &mdlm_detail_desc, 162 (struct usb_descriptor_header *) ðer_desc, 163 (struct usb_descriptor_header *) &fs_subset_in_desc, 164 (struct usb_descriptor_header *) &fs_subset_out_desc, 165 NULL, 166 }; 167 168 /* high speed support: */ 169 170 static struct usb_endpoint_descriptor hs_subset_in_desc = { 171 .bLength = USB_DT_ENDPOINT_SIZE, 172 .bDescriptorType = USB_DT_ENDPOINT, 173 174 .bmAttributes = USB_ENDPOINT_XFER_BULK, 175 .wMaxPacketSize = cpu_to_le16(512), 176 }; 177 178 static struct usb_endpoint_descriptor hs_subset_out_desc = { 179 .bLength = USB_DT_ENDPOINT_SIZE, 180 .bDescriptorType = USB_DT_ENDPOINT, 181 182 .bmAttributes = USB_ENDPOINT_XFER_BULK, 183 .wMaxPacketSize = cpu_to_le16(512), 184 }; 185 186 static struct usb_descriptor_header *hs_eth_function[] = { 187 (struct usb_descriptor_header *) &subset_data_intf, 188 (struct usb_descriptor_header *) &mdlm_header_desc, 189 (struct usb_descriptor_header *) &mdlm_desc, 190 (struct usb_descriptor_header *) &mdlm_detail_desc, 191 (struct usb_descriptor_header *) ðer_desc, 192 (struct usb_descriptor_header *) &hs_subset_in_desc, 193 (struct usb_descriptor_header *) &hs_subset_out_desc, 194 NULL, 195 }; 196 197 /* super speed support: */ 198 199 static struct usb_endpoint_descriptor ss_subset_in_desc = { 200 .bLength = USB_DT_ENDPOINT_SIZE, 201 .bDescriptorType = USB_DT_ENDPOINT, 202 203 .bmAttributes = USB_ENDPOINT_XFER_BULK, 204 .wMaxPacketSize = cpu_to_le16(1024), 205 }; 206 207 static struct usb_endpoint_descriptor ss_subset_out_desc = { 208 .bLength = USB_DT_ENDPOINT_SIZE, 209 .bDescriptorType = USB_DT_ENDPOINT, 210 211 .bmAttributes = USB_ENDPOINT_XFER_BULK, 212 .wMaxPacketSize = cpu_to_le16(1024), 213 }; 214 215 static struct usb_ss_ep_comp_descriptor ss_subset_bulk_comp_desc = { 216 .bLength = sizeof ss_subset_bulk_comp_desc, 217 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP, 218 219 /* the following 2 values can be tweaked if necessary */ 220 /* .bMaxBurst = 0, */ 221 /* .bmAttributes = 0, */ 222 }; 223 224 static struct usb_descriptor_header *ss_eth_function[] = { 225 (struct usb_descriptor_header *) &subset_data_intf, 226 (struct usb_descriptor_header *) &mdlm_header_desc, 227 (struct usb_descriptor_header *) &mdlm_desc, 228 (struct usb_descriptor_header *) &mdlm_detail_desc, 229 (struct usb_descriptor_header *) ðer_desc, 230 (struct usb_descriptor_header *) &ss_subset_in_desc, 231 (struct usb_descriptor_header *) &ss_subset_bulk_comp_desc, 232 (struct usb_descriptor_header *) &ss_subset_out_desc, 233 (struct usb_descriptor_header *) &ss_subset_bulk_comp_desc, 234 NULL, 235 }; 236 237 /* string descriptors: */ 238 239 static struct usb_string geth_string_defs[] = { 240 [0].s = "CDC Ethernet Subset/SAFE", 241 [1].s = "", 242 { } /* end of list */ 243 }; 244 245 static struct usb_gadget_strings geth_string_table = { 246 .language = 0x0409, /* en-us */ 247 .strings = geth_string_defs, 248 }; 249 250 static struct usb_gadget_strings *geth_strings[] = { 251 &geth_string_table, 252 NULL, 253 }; 254 255 /*-------------------------------------------------------------------------*/ 256 257 static int geth_set_alt(struct usb_function *f, unsigned intf, unsigned alt) 258 { 259 struct f_gether *geth = func_to_geth(f); 260 struct usb_composite_dev *cdev = f->config->cdev; 261 struct net_device *net; 262 263 /* we know alt == 0, so this is an activation or a reset */ 264 265 if (geth->port.in_ep->enabled) { 266 DBG(cdev, "reset cdc subset\n"); 267 gether_disconnect(&geth->port); 268 } 269 270 DBG(cdev, "init + activate cdc subset\n"); 271 if (config_ep_by_speed(cdev->gadget, f, geth->port.in_ep) || 272 config_ep_by_speed(cdev->gadget, f, geth->port.out_ep)) { 273 geth->port.in_ep->desc = NULL; 274 geth->port.out_ep->desc = NULL; 275 return -EINVAL; 276 } 277 278 net = gether_connect(&geth->port); 279 return PTR_ERR_OR_ZERO(net); 280 } 281 282 static void geth_disable(struct usb_function *f) 283 { 284 struct f_gether *geth = func_to_geth(f); 285 struct usb_composite_dev *cdev = f->config->cdev; 286 287 DBG(cdev, "net deactivated\n"); 288 gether_disconnect(&geth->port); 289 } 290 291 /*-------------------------------------------------------------------------*/ 292 293 /* serial function driver setup/binding */ 294 295 static int 296 geth_bind(struct usb_configuration *c, struct usb_function *f) 297 { 298 struct usb_composite_dev *cdev = c->cdev; 299 struct f_gether *geth = func_to_geth(f); 300 struct usb_string *us; 301 int status; 302 struct usb_ep *ep; 303 304 struct f_gether_opts *gether_opts; 305 306 gether_opts = container_of(f->fi, struct f_gether_opts, func_inst); 307 308 /* 309 * in drivers/usb/gadget/configfs.c:configfs_composite_bind() 310 * configurations are bound in sequence with list_for_each_entry, 311 * in each configuration its functions are bound in sequence 312 * with list_for_each_entry, so we assume no race condition 313 * with regard to gether_opts->bound access 314 */ 315 if (!gether_opts->bound) { 316 mutex_lock(&gether_opts->lock); 317 gether_set_gadget(gether_opts->net, cdev->gadget); 318 status = gether_register_netdev(gether_opts->net); 319 mutex_unlock(&gether_opts->lock); 320 if (status) 321 return status; 322 gether_opts->bound = true; 323 } 324 325 us = usb_gstrings_attach(cdev, geth_strings, 326 ARRAY_SIZE(geth_string_defs)); 327 if (IS_ERR(us)) 328 return PTR_ERR(us); 329 330 subset_data_intf.iInterface = us[0].id; 331 ether_desc.iMACAddress = us[1].id; 332 333 /* allocate instance-specific interface IDs */ 334 status = usb_interface_id(c, f); 335 if (status < 0) 336 goto fail; 337 subset_data_intf.bInterfaceNumber = status; 338 339 status = -ENODEV; 340 341 /* allocate instance-specific endpoints */ 342 ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_in_desc); 343 if (!ep) 344 goto fail; 345 geth->port.in_ep = ep; 346 347 ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_out_desc); 348 if (!ep) 349 goto fail; 350 geth->port.out_ep = ep; 351 352 /* support all relevant hardware speeds... we expect that when 353 * hardware is dual speed, all bulk-capable endpoints work at 354 * both speeds 355 */ 356 hs_subset_in_desc.bEndpointAddress = fs_subset_in_desc.bEndpointAddress; 357 hs_subset_out_desc.bEndpointAddress = 358 fs_subset_out_desc.bEndpointAddress; 359 360 ss_subset_in_desc.bEndpointAddress = fs_subset_in_desc.bEndpointAddress; 361 ss_subset_out_desc.bEndpointAddress = 362 fs_subset_out_desc.bEndpointAddress; 363 364 status = usb_assign_descriptors(f, fs_eth_function, hs_eth_function, 365 ss_eth_function); 366 if (status) 367 goto fail; 368 369 /* NOTE: all that is done without knowing or caring about 370 * the network link ... which is unavailable to this code 371 * until we're activated via set_alt(). 372 */ 373 374 DBG(cdev, "CDC Subset: %s speed IN/%s OUT/%s\n", 375 gadget_is_superspeed(c->cdev->gadget) ? "super" : 376 gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full", 377 geth->port.in_ep->name, geth->port.out_ep->name); 378 return 0; 379 380 fail: 381 ERROR(cdev, "%s: can't bind, err %d\n", f->name, status); 382 383 return status; 384 } 385 386 static inline struct f_gether_opts *to_f_gether_opts(struct config_item *item) 387 { 388 return container_of(to_config_group(item), struct f_gether_opts, 389 func_inst.group); 390 } 391 392 /* f_gether_item_ops */ 393 USB_ETHERNET_CONFIGFS_ITEM(gether); 394 395 /* f_gether_opts_dev_addr */ 396 USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(gether); 397 398 /* f_gether_opts_host_addr */ 399 USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(gether); 400 401 /* f_gether_opts_qmult */ 402 USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(gether); 403 404 /* f_gether_opts_ifname */ 405 USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(gether); 406 407 static struct configfs_attribute *gether_attrs[] = { 408 &gether_opts_attr_dev_addr, 409 &gether_opts_attr_host_addr, 410 &gether_opts_attr_qmult, 411 &gether_opts_attr_ifname, 412 NULL, 413 }; 414 415 static struct config_item_type gether_func_type = { 416 .ct_item_ops = &gether_item_ops, 417 .ct_attrs = gether_attrs, 418 .ct_owner = THIS_MODULE, 419 }; 420 421 static void geth_free_inst(struct usb_function_instance *f) 422 { 423 struct f_gether_opts *opts; 424 425 opts = container_of(f, struct f_gether_opts, func_inst); 426 if (opts->bound) 427 gether_cleanup(netdev_priv(opts->net)); 428 else 429 free_netdev(opts->net); 430 kfree(opts); 431 } 432 433 static struct usb_function_instance *geth_alloc_inst(void) 434 { 435 struct f_gether_opts *opts; 436 437 opts = kzalloc(sizeof(*opts), GFP_KERNEL); 438 if (!opts) 439 return ERR_PTR(-ENOMEM); 440 mutex_init(&opts->lock); 441 opts->func_inst.free_func_inst = geth_free_inst; 442 opts->net = gether_setup_default(); 443 if (IS_ERR(opts->net)) { 444 struct net_device *net = opts->net; 445 kfree(opts); 446 return ERR_CAST(net); 447 } 448 449 config_group_init_type_name(&opts->func_inst.group, "", 450 &gether_func_type); 451 452 return &opts->func_inst; 453 } 454 455 static void geth_free(struct usb_function *f) 456 { 457 struct f_gether *eth; 458 459 eth = func_to_geth(f); 460 kfree(eth); 461 } 462 463 static void geth_unbind(struct usb_configuration *c, struct usb_function *f) 464 { 465 geth_string_defs[0].id = 0; 466 usb_free_all_descriptors(f); 467 } 468 469 static struct usb_function *geth_alloc(struct usb_function_instance *fi) 470 { 471 struct f_gether *geth; 472 struct f_gether_opts *opts; 473 int status; 474 475 /* allocate and initialize one new instance */ 476 geth = kzalloc(sizeof(*geth), GFP_KERNEL); 477 if (!geth) 478 return ERR_PTR(-ENOMEM); 479 480 opts = container_of(fi, struct f_gether_opts, func_inst); 481 482 mutex_lock(&opts->lock); 483 opts->refcnt++; 484 /* export host's Ethernet address in CDC format */ 485 status = gether_get_host_addr_cdc(opts->net, geth->ethaddr, 486 sizeof(geth->ethaddr)); 487 if (status < 12) { 488 kfree(geth); 489 mutex_unlock(&opts->lock); 490 return ERR_PTR(-EINVAL); 491 } 492 geth_string_defs[1].s = geth->ethaddr; 493 494 geth->port.ioport = netdev_priv(opts->net); 495 mutex_unlock(&opts->lock); 496 geth->port.cdc_filter = DEFAULT_FILTER; 497 498 geth->port.func.name = "cdc_subset"; 499 geth->port.func.bind = geth_bind; 500 geth->port.func.unbind = geth_unbind; 501 geth->port.func.set_alt = geth_set_alt; 502 geth->port.func.disable = geth_disable; 503 geth->port.func.free_func = geth_free; 504 505 return &geth->port.func; 506 } 507 508 DECLARE_USB_FUNCTION_INIT(geth, geth_alloc_inst, geth_alloc); 509 MODULE_LICENSE("GPL"); 510 MODULE_AUTHOR("David Brownell"); 511