1 /* 2 * f_eem.c -- USB CDC Ethernet (EEM) link function driver 3 * 4 * Copyright (C) 2003-2005,2008 David Brownell 5 * Copyright (C) 2008 Nokia Corporation 6 * Copyright (C) 2009 EF Johnson Technologies 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 14 #include <linux/kernel.h> 15 #include <linux/module.h> 16 #include <linux/device.h> 17 #include <linux/etherdevice.h> 18 #include <linux/crc32.h> 19 #include <linux/slab.h> 20 21 #include "u_ether.h" 22 #include "u_ether_configfs.h" 23 #include "u_eem.h" 24 25 #define EEM_HLEN 2 26 27 /* 28 * This function is a "CDC Ethernet Emulation Model" (CDC EEM) 29 * Ethernet link. 30 */ 31 32 struct f_eem { 33 struct gether port; 34 u8 ctrl_id; 35 }; 36 37 static inline struct f_eem *func_to_eem(struct usb_function *f) 38 { 39 return container_of(f, struct f_eem, port.func); 40 } 41 42 /*-------------------------------------------------------------------------*/ 43 44 /* interface descriptor: */ 45 46 static struct usb_interface_descriptor eem_intf = { 47 .bLength = sizeof eem_intf, 48 .bDescriptorType = USB_DT_INTERFACE, 49 50 /* .bInterfaceNumber = DYNAMIC */ 51 .bNumEndpoints = 2, 52 .bInterfaceClass = USB_CLASS_COMM, 53 .bInterfaceSubClass = USB_CDC_SUBCLASS_EEM, 54 .bInterfaceProtocol = USB_CDC_PROTO_EEM, 55 /* .iInterface = DYNAMIC */ 56 }; 57 58 /* full speed support: */ 59 60 static struct usb_endpoint_descriptor eem_fs_in_desc = { 61 .bLength = USB_DT_ENDPOINT_SIZE, 62 .bDescriptorType = USB_DT_ENDPOINT, 63 64 .bEndpointAddress = USB_DIR_IN, 65 .bmAttributes = USB_ENDPOINT_XFER_BULK, 66 }; 67 68 static struct usb_endpoint_descriptor eem_fs_out_desc = { 69 .bLength = USB_DT_ENDPOINT_SIZE, 70 .bDescriptorType = USB_DT_ENDPOINT, 71 72 .bEndpointAddress = USB_DIR_OUT, 73 .bmAttributes = USB_ENDPOINT_XFER_BULK, 74 }; 75 76 static struct usb_descriptor_header *eem_fs_function[] = { 77 /* CDC EEM control descriptors */ 78 (struct usb_descriptor_header *) &eem_intf, 79 (struct usb_descriptor_header *) &eem_fs_in_desc, 80 (struct usb_descriptor_header *) &eem_fs_out_desc, 81 NULL, 82 }; 83 84 /* high speed support: */ 85 86 static struct usb_endpoint_descriptor eem_hs_in_desc = { 87 .bLength = USB_DT_ENDPOINT_SIZE, 88 .bDescriptorType = USB_DT_ENDPOINT, 89 90 .bEndpointAddress = USB_DIR_IN, 91 .bmAttributes = USB_ENDPOINT_XFER_BULK, 92 .wMaxPacketSize = cpu_to_le16(512), 93 }; 94 95 static struct usb_endpoint_descriptor eem_hs_out_desc = { 96 .bLength = USB_DT_ENDPOINT_SIZE, 97 .bDescriptorType = USB_DT_ENDPOINT, 98 99 .bEndpointAddress = USB_DIR_OUT, 100 .bmAttributes = USB_ENDPOINT_XFER_BULK, 101 .wMaxPacketSize = cpu_to_le16(512), 102 }; 103 104 static struct usb_descriptor_header *eem_hs_function[] = { 105 /* CDC EEM control descriptors */ 106 (struct usb_descriptor_header *) &eem_intf, 107 (struct usb_descriptor_header *) &eem_hs_in_desc, 108 (struct usb_descriptor_header *) &eem_hs_out_desc, 109 NULL, 110 }; 111 112 /* super speed support: */ 113 114 static struct usb_endpoint_descriptor eem_ss_in_desc = { 115 .bLength = USB_DT_ENDPOINT_SIZE, 116 .bDescriptorType = USB_DT_ENDPOINT, 117 118 .bEndpointAddress = USB_DIR_IN, 119 .bmAttributes = USB_ENDPOINT_XFER_BULK, 120 .wMaxPacketSize = cpu_to_le16(1024), 121 }; 122 123 static struct usb_endpoint_descriptor eem_ss_out_desc = { 124 .bLength = USB_DT_ENDPOINT_SIZE, 125 .bDescriptorType = USB_DT_ENDPOINT, 126 127 .bEndpointAddress = USB_DIR_OUT, 128 .bmAttributes = USB_ENDPOINT_XFER_BULK, 129 .wMaxPacketSize = cpu_to_le16(1024), 130 }; 131 132 static struct usb_ss_ep_comp_descriptor eem_ss_bulk_comp_desc = { 133 .bLength = sizeof eem_ss_bulk_comp_desc, 134 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP, 135 136 /* the following 2 values can be tweaked if necessary */ 137 /* .bMaxBurst = 0, */ 138 /* .bmAttributes = 0, */ 139 }; 140 141 static struct usb_descriptor_header *eem_ss_function[] = { 142 /* CDC EEM control descriptors */ 143 (struct usb_descriptor_header *) &eem_intf, 144 (struct usb_descriptor_header *) &eem_ss_in_desc, 145 (struct usb_descriptor_header *) &eem_ss_bulk_comp_desc, 146 (struct usb_descriptor_header *) &eem_ss_out_desc, 147 (struct usb_descriptor_header *) &eem_ss_bulk_comp_desc, 148 NULL, 149 }; 150 151 /* string descriptors: */ 152 153 static struct usb_string eem_string_defs[] = { 154 [0].s = "CDC Ethernet Emulation Model (EEM)", 155 { } /* end of list */ 156 }; 157 158 static struct usb_gadget_strings eem_string_table = { 159 .language = 0x0409, /* en-us */ 160 .strings = eem_string_defs, 161 }; 162 163 static struct usb_gadget_strings *eem_strings[] = { 164 &eem_string_table, 165 NULL, 166 }; 167 168 /*-------------------------------------------------------------------------*/ 169 170 static int eem_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl) 171 { 172 struct usb_composite_dev *cdev = f->config->cdev; 173 int value = -EOPNOTSUPP; 174 u16 w_index = le16_to_cpu(ctrl->wIndex); 175 u16 w_value = le16_to_cpu(ctrl->wValue); 176 u16 w_length = le16_to_cpu(ctrl->wLength); 177 178 DBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n", 179 ctrl->bRequestType, ctrl->bRequest, 180 w_value, w_index, w_length); 181 182 /* device either stalls (value < 0) or reports success */ 183 return value; 184 } 185 186 187 static int eem_set_alt(struct usb_function *f, unsigned intf, unsigned alt) 188 { 189 struct f_eem *eem = func_to_eem(f); 190 struct usb_composite_dev *cdev = f->config->cdev; 191 struct net_device *net; 192 193 /* we know alt == 0, so this is an activation or a reset */ 194 if (alt != 0) 195 goto fail; 196 197 if (intf == eem->ctrl_id) { 198 DBG(cdev, "reset eem\n"); 199 gether_disconnect(&eem->port); 200 201 if (!eem->port.in_ep->desc || !eem->port.out_ep->desc) { 202 DBG(cdev, "init eem\n"); 203 if (config_ep_by_speed(cdev->gadget, f, 204 eem->port.in_ep) || 205 config_ep_by_speed(cdev->gadget, f, 206 eem->port.out_ep)) { 207 eem->port.in_ep->desc = NULL; 208 eem->port.out_ep->desc = NULL; 209 goto fail; 210 } 211 } 212 213 /* zlps should not occur because zero-length EEM packets 214 * will be inserted in those cases where they would occur 215 */ 216 eem->port.is_zlp_ok = 1; 217 eem->port.cdc_filter = DEFAULT_FILTER; 218 DBG(cdev, "activate eem\n"); 219 net = gether_connect(&eem->port); 220 if (IS_ERR(net)) 221 return PTR_ERR(net); 222 } else 223 goto fail; 224 225 return 0; 226 fail: 227 return -EINVAL; 228 } 229 230 static void eem_disable(struct usb_function *f) 231 { 232 struct f_eem *eem = func_to_eem(f); 233 struct usb_composite_dev *cdev = f->config->cdev; 234 235 DBG(cdev, "eem deactivated\n"); 236 237 if (eem->port.in_ep->enabled) 238 gether_disconnect(&eem->port); 239 } 240 241 /*-------------------------------------------------------------------------*/ 242 243 /* EEM function driver setup/binding */ 244 245 static int eem_bind(struct usb_configuration *c, struct usb_function *f) 246 { 247 struct usb_composite_dev *cdev = c->cdev; 248 struct f_eem *eem = func_to_eem(f); 249 struct usb_string *us; 250 int status; 251 struct usb_ep *ep; 252 253 struct f_eem_opts *eem_opts; 254 255 eem_opts = container_of(f->fi, struct f_eem_opts, func_inst); 256 /* 257 * in drivers/usb/gadget/configfs.c:configfs_composite_bind() 258 * configurations are bound in sequence with list_for_each_entry, 259 * in each configuration its functions are bound in sequence 260 * with list_for_each_entry, so we assume no race condition 261 * with regard to eem_opts->bound access 262 */ 263 if (!eem_opts->bound) { 264 mutex_lock(&eem_opts->lock); 265 gether_set_gadget(eem_opts->net, cdev->gadget); 266 status = gether_register_netdev(eem_opts->net); 267 mutex_unlock(&eem_opts->lock); 268 if (status) 269 return status; 270 eem_opts->bound = true; 271 } 272 273 us = usb_gstrings_attach(cdev, eem_strings, 274 ARRAY_SIZE(eem_string_defs)); 275 if (IS_ERR(us)) 276 return PTR_ERR(us); 277 eem_intf.iInterface = us[0].id; 278 279 /* allocate instance-specific interface IDs */ 280 status = usb_interface_id(c, f); 281 if (status < 0) 282 goto fail; 283 eem->ctrl_id = status; 284 eem_intf.bInterfaceNumber = status; 285 286 status = -ENODEV; 287 288 /* allocate instance-specific endpoints */ 289 ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_in_desc); 290 if (!ep) 291 goto fail; 292 eem->port.in_ep = ep; 293 294 ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_out_desc); 295 if (!ep) 296 goto fail; 297 eem->port.out_ep = ep; 298 299 status = -ENOMEM; 300 301 /* support all relevant hardware speeds... we expect that when 302 * hardware is dual speed, all bulk-capable endpoints work at 303 * both speeds 304 */ 305 eem_hs_in_desc.bEndpointAddress = eem_fs_in_desc.bEndpointAddress; 306 eem_hs_out_desc.bEndpointAddress = eem_fs_out_desc.bEndpointAddress; 307 308 eem_ss_in_desc.bEndpointAddress = eem_fs_in_desc.bEndpointAddress; 309 eem_ss_out_desc.bEndpointAddress = eem_fs_out_desc.bEndpointAddress; 310 311 status = usb_assign_descriptors(f, eem_fs_function, eem_hs_function, 312 eem_ss_function, NULL); 313 if (status) 314 goto fail; 315 316 DBG(cdev, "CDC Ethernet (EEM): %s speed IN/%s OUT/%s\n", 317 gadget_is_superspeed(c->cdev->gadget) ? "super" : 318 gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full", 319 eem->port.in_ep->name, eem->port.out_ep->name); 320 return 0; 321 322 fail: 323 ERROR(cdev, "%s: can't bind, err %d\n", f->name, status); 324 325 return status; 326 } 327 328 static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req) 329 { 330 struct sk_buff *skb = (struct sk_buff *)req->context; 331 332 dev_kfree_skb_any(skb); 333 } 334 335 /* 336 * Add the EEM header and ethernet checksum. 337 * We currently do not attempt to put multiple ethernet frames 338 * into a single USB transfer 339 */ 340 static struct sk_buff *eem_wrap(struct gether *port, struct sk_buff *skb) 341 { 342 struct sk_buff *skb2 = NULL; 343 struct usb_ep *in = port->in_ep; 344 int padlen = 0; 345 u16 len = skb->len; 346 347 int headroom = skb_headroom(skb); 348 int tailroom = skb_tailroom(skb); 349 350 /* When (len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) is 0, 351 * stick two bytes of zero-length EEM packet on the end. 352 */ 353 if (((len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) == 0) 354 padlen += 2; 355 356 if ((tailroom >= (ETH_FCS_LEN + padlen)) && 357 (headroom >= EEM_HLEN) && !skb_cloned(skb)) 358 goto done; 359 360 skb2 = skb_copy_expand(skb, EEM_HLEN, ETH_FCS_LEN + padlen, GFP_ATOMIC); 361 dev_kfree_skb_any(skb); 362 skb = skb2; 363 if (!skb) 364 return skb; 365 366 done: 367 /* use the "no CRC" option */ 368 put_unaligned_be32(0xdeadbeef, skb_put(skb, 4)); 369 370 /* EEM packet header format: 371 * b0..13: length of ethernet frame 372 * b14: bmCRC (0 == sentinel CRC) 373 * b15: bmType (0 == data) 374 */ 375 len = skb->len; 376 put_unaligned_le16(len & 0x3FFF, skb_push(skb, 2)); 377 378 /* add a zero-length EEM packet, if needed */ 379 if (padlen) 380 put_unaligned_le16(0, skb_put(skb, 2)); 381 382 return skb; 383 } 384 385 /* 386 * Remove the EEM header. Note that there can be many EEM packets in a single 387 * USB transfer, so we need to break them out and handle them independently. 388 */ 389 static int eem_unwrap(struct gether *port, 390 struct sk_buff *skb, 391 struct sk_buff_head *list) 392 { 393 struct usb_composite_dev *cdev = port->func.config->cdev; 394 int status = 0; 395 396 do { 397 struct sk_buff *skb2; 398 u16 header; 399 u16 len = 0; 400 401 if (skb->len < EEM_HLEN) { 402 status = -EINVAL; 403 DBG(cdev, "invalid EEM header\n"); 404 goto error; 405 } 406 407 /* remove the EEM header */ 408 header = get_unaligned_le16(skb->data); 409 skb_pull(skb, EEM_HLEN); 410 411 /* EEM packet header format: 412 * b0..14: EEM type dependent (data or command) 413 * b15: bmType (0 == data, 1 == command) 414 */ 415 if (header & BIT(15)) { 416 struct usb_request *req = cdev->req; 417 u16 bmEEMCmd; 418 419 /* EEM command packet format: 420 * b0..10: bmEEMCmdParam 421 * b11..13: bmEEMCmd 422 * b14: reserved (must be zero) 423 * b15: bmType (1 == command) 424 */ 425 if (header & BIT(14)) 426 continue; 427 428 bmEEMCmd = (header >> 11) & 0x7; 429 switch (bmEEMCmd) { 430 case 0: /* echo */ 431 len = header & 0x7FF; 432 if (skb->len < len) { 433 status = -EOVERFLOW; 434 goto error; 435 } 436 437 skb2 = skb_clone(skb, GFP_ATOMIC); 438 if (unlikely(!skb2)) { 439 DBG(cdev, "EEM echo response error\n"); 440 goto next; 441 } 442 skb_trim(skb2, len); 443 put_unaligned_le16(BIT(15) | BIT(11) | len, 444 skb_push(skb2, 2)); 445 skb_copy_bits(skb2, 0, req->buf, skb2->len); 446 req->length = skb2->len; 447 req->complete = eem_cmd_complete; 448 req->zero = 1; 449 req->context = skb2; 450 if (usb_ep_queue(port->in_ep, req, GFP_ATOMIC)) 451 DBG(cdev, "echo response queue fail\n"); 452 break; 453 454 case 1: /* echo response */ 455 case 2: /* suspend hint */ 456 case 3: /* response hint */ 457 case 4: /* response complete hint */ 458 case 5: /* tickle */ 459 default: /* reserved */ 460 continue; 461 } 462 } else { 463 u32 crc, crc2; 464 struct sk_buff *skb3; 465 466 /* check for zero-length EEM packet */ 467 if (header == 0) 468 continue; 469 470 /* EEM data packet format: 471 * b0..13: length of ethernet frame 472 * b14: bmCRC (0 == sentinel, 1 == calculated) 473 * b15: bmType (0 == data) 474 */ 475 len = header & 0x3FFF; 476 if ((skb->len < len) 477 || (len < (ETH_HLEN + ETH_FCS_LEN))) { 478 status = -EINVAL; 479 goto error; 480 } 481 482 /* validate CRC */ 483 if (header & BIT(14)) { 484 crc = get_unaligned_le32(skb->data + len 485 - ETH_FCS_LEN); 486 crc2 = ~crc32_le(~0, 487 skb->data, len - ETH_FCS_LEN); 488 } else { 489 crc = get_unaligned_be32(skb->data + len 490 - ETH_FCS_LEN); 491 crc2 = 0xdeadbeef; 492 } 493 if (crc != crc2) { 494 DBG(cdev, "invalid EEM CRC\n"); 495 goto next; 496 } 497 498 skb2 = skb_clone(skb, GFP_ATOMIC); 499 if (unlikely(!skb2)) { 500 DBG(cdev, "unable to unframe EEM packet\n"); 501 continue; 502 } 503 skb_trim(skb2, len - ETH_FCS_LEN); 504 505 skb3 = skb_copy_expand(skb2, 506 NET_IP_ALIGN, 507 0, 508 GFP_ATOMIC); 509 if (unlikely(!skb3)) { 510 DBG(cdev, "unable to realign EEM packet\n"); 511 dev_kfree_skb_any(skb2); 512 continue; 513 } 514 dev_kfree_skb_any(skb2); 515 skb_queue_tail(list, skb3); 516 } 517 next: 518 skb_pull(skb, len); 519 } while (skb->len); 520 521 error: 522 dev_kfree_skb_any(skb); 523 return status; 524 } 525 526 static inline struct f_eem_opts *to_f_eem_opts(struct config_item *item) 527 { 528 return container_of(to_config_group(item), struct f_eem_opts, 529 func_inst.group); 530 } 531 532 /* f_eem_item_ops */ 533 USB_ETHERNET_CONFIGFS_ITEM(eem); 534 535 /* f_eem_opts_dev_addr */ 536 USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(eem); 537 538 /* f_eem_opts_host_addr */ 539 USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(eem); 540 541 /* f_eem_opts_qmult */ 542 USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(eem); 543 544 /* f_eem_opts_ifname */ 545 USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(eem); 546 547 static struct configfs_attribute *eem_attrs[] = { 548 &eem_opts_attr_dev_addr, 549 &eem_opts_attr_host_addr, 550 &eem_opts_attr_qmult, 551 &eem_opts_attr_ifname, 552 NULL, 553 }; 554 555 static struct config_item_type eem_func_type = { 556 .ct_item_ops = &eem_item_ops, 557 .ct_attrs = eem_attrs, 558 .ct_owner = THIS_MODULE, 559 }; 560 561 static void eem_free_inst(struct usb_function_instance *f) 562 { 563 struct f_eem_opts *opts; 564 565 opts = container_of(f, struct f_eem_opts, func_inst); 566 if (opts->bound) 567 gether_cleanup(netdev_priv(opts->net)); 568 else 569 free_netdev(opts->net); 570 kfree(opts); 571 } 572 573 static struct usb_function_instance *eem_alloc_inst(void) 574 { 575 struct f_eem_opts *opts; 576 577 opts = kzalloc(sizeof(*opts), GFP_KERNEL); 578 if (!opts) 579 return ERR_PTR(-ENOMEM); 580 mutex_init(&opts->lock); 581 opts->func_inst.free_func_inst = eem_free_inst; 582 opts->net = gether_setup_default(); 583 if (IS_ERR(opts->net)) { 584 struct net_device *net = opts->net; 585 kfree(opts); 586 return ERR_CAST(net); 587 } 588 589 config_group_init_type_name(&opts->func_inst.group, "", &eem_func_type); 590 591 return &opts->func_inst; 592 } 593 594 static void eem_free(struct usb_function *f) 595 { 596 struct f_eem *eem; 597 struct f_eem_opts *opts; 598 599 eem = func_to_eem(f); 600 opts = container_of(f->fi, struct f_eem_opts, func_inst); 601 kfree(eem); 602 mutex_lock(&opts->lock); 603 opts->refcnt--; 604 mutex_unlock(&opts->lock); 605 } 606 607 static void eem_unbind(struct usb_configuration *c, struct usb_function *f) 608 { 609 DBG(c->cdev, "eem unbind\n"); 610 611 usb_free_all_descriptors(f); 612 } 613 614 static struct usb_function *eem_alloc(struct usb_function_instance *fi) 615 { 616 struct f_eem *eem; 617 struct f_eem_opts *opts; 618 619 /* allocate and initialize one new instance */ 620 eem = kzalloc(sizeof(*eem), GFP_KERNEL); 621 if (!eem) 622 return ERR_PTR(-ENOMEM); 623 624 opts = container_of(fi, struct f_eem_opts, func_inst); 625 mutex_lock(&opts->lock); 626 opts->refcnt++; 627 628 eem->port.ioport = netdev_priv(opts->net); 629 mutex_unlock(&opts->lock); 630 eem->port.cdc_filter = DEFAULT_FILTER; 631 632 eem->port.func.name = "cdc_eem"; 633 /* descriptors are per-instance copies */ 634 eem->port.func.bind = eem_bind; 635 eem->port.func.unbind = eem_unbind; 636 eem->port.func.set_alt = eem_set_alt; 637 eem->port.func.setup = eem_setup; 638 eem->port.func.disable = eem_disable; 639 eem->port.func.free_func = eem_free; 640 eem->port.wrap = eem_wrap; 641 eem->port.unwrap = eem_unwrap; 642 eem->port.header_len = EEM_HLEN; 643 644 return &eem->port.func; 645 } 646 647 DECLARE_USB_FUNCTION_INIT(eem, eem_alloc_inst, eem_alloc); 648 MODULE_LICENSE("GPL"); 649 MODULE_AUTHOR("David Brownell"); 650