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) { 198 199 if (eem->port.in_ep->driver_data) { 200 DBG(cdev, "reset eem\n"); 201 gether_disconnect(&eem->port); 202 } 203 204 if (!eem->port.in_ep->desc || !eem->port.out_ep->desc) { 205 DBG(cdev, "init eem\n"); 206 if (config_ep_by_speed(cdev->gadget, f, 207 eem->port.in_ep) || 208 config_ep_by_speed(cdev->gadget, f, 209 eem->port.out_ep)) { 210 eem->port.in_ep->desc = NULL; 211 eem->port.out_ep->desc = NULL; 212 goto fail; 213 } 214 } 215 216 /* zlps should not occur because zero-length EEM packets 217 * will be inserted in those cases where they would occur 218 */ 219 eem->port.is_zlp_ok = 1; 220 eem->port.cdc_filter = DEFAULT_FILTER; 221 DBG(cdev, "activate eem\n"); 222 net = gether_connect(&eem->port); 223 if (IS_ERR(net)) 224 return PTR_ERR(net); 225 } else 226 goto fail; 227 228 return 0; 229 fail: 230 return -EINVAL; 231 } 232 233 static void eem_disable(struct usb_function *f) 234 { 235 struct f_eem *eem = func_to_eem(f); 236 struct usb_composite_dev *cdev = f->config->cdev; 237 238 DBG(cdev, "eem deactivated\n"); 239 240 if (eem->port.in_ep->driver_data) 241 gether_disconnect(&eem->port); 242 } 243 244 /*-------------------------------------------------------------------------*/ 245 246 /* EEM function driver setup/binding */ 247 248 static int eem_bind(struct usb_configuration *c, struct usb_function *f) 249 { 250 struct usb_composite_dev *cdev = c->cdev; 251 struct f_eem *eem = func_to_eem(f); 252 struct usb_string *us; 253 int status; 254 struct usb_ep *ep; 255 256 struct f_eem_opts *eem_opts; 257 258 eem_opts = container_of(f->fi, struct f_eem_opts, func_inst); 259 /* 260 * in drivers/usb/gadget/configfs.c:configfs_composite_bind() 261 * configurations are bound in sequence with list_for_each_entry, 262 * in each configuration its functions are bound in sequence 263 * with list_for_each_entry, so we assume no race condition 264 * with regard to eem_opts->bound access 265 */ 266 if (!eem_opts->bound) { 267 mutex_lock(&eem_opts->lock); 268 gether_set_gadget(eem_opts->net, cdev->gadget); 269 status = gether_register_netdev(eem_opts->net); 270 mutex_unlock(&eem_opts->lock); 271 if (status) 272 return status; 273 eem_opts->bound = true; 274 } 275 276 us = usb_gstrings_attach(cdev, eem_strings, 277 ARRAY_SIZE(eem_string_defs)); 278 if (IS_ERR(us)) 279 return PTR_ERR(us); 280 eem_intf.iInterface = us[0].id; 281 282 /* allocate instance-specific interface IDs */ 283 status = usb_interface_id(c, f); 284 if (status < 0) 285 goto fail; 286 eem->ctrl_id = status; 287 eem_intf.bInterfaceNumber = status; 288 289 status = -ENODEV; 290 291 /* allocate instance-specific endpoints */ 292 ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_in_desc); 293 if (!ep) 294 goto fail; 295 eem->port.in_ep = ep; 296 ep->driver_data = cdev; /* claim */ 297 298 ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_out_desc); 299 if (!ep) 300 goto fail; 301 eem->port.out_ep = ep; 302 ep->driver_data = cdev; /* claim */ 303 304 status = -ENOMEM; 305 306 /* support all relevant hardware speeds... we expect that when 307 * hardware is dual speed, all bulk-capable endpoints work at 308 * both speeds 309 */ 310 eem_hs_in_desc.bEndpointAddress = eem_fs_in_desc.bEndpointAddress; 311 eem_hs_out_desc.bEndpointAddress = eem_fs_out_desc.bEndpointAddress; 312 313 eem_ss_in_desc.bEndpointAddress = eem_fs_in_desc.bEndpointAddress; 314 eem_ss_out_desc.bEndpointAddress = eem_fs_out_desc.bEndpointAddress; 315 316 status = usb_assign_descriptors(f, eem_fs_function, eem_hs_function, 317 eem_ss_function); 318 if (status) 319 goto fail; 320 321 DBG(cdev, "CDC Ethernet (EEM): %s speed IN/%s OUT/%s\n", 322 gadget_is_superspeed(c->cdev->gadget) ? "super" : 323 gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full", 324 eem->port.in_ep->name, eem->port.out_ep->name); 325 return 0; 326 327 fail: 328 if (eem->port.out_ep) 329 eem->port.out_ep->driver_data = NULL; 330 if (eem->port.in_ep) 331 eem->port.in_ep->driver_data = NULL; 332 333 ERROR(cdev, "%s: can't bind, err %d\n", f->name, status); 334 335 return status; 336 } 337 338 static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req) 339 { 340 struct sk_buff *skb = (struct sk_buff *)req->context; 341 342 dev_kfree_skb_any(skb); 343 } 344 345 /* 346 * Add the EEM header and ethernet checksum. 347 * We currently do not attempt to put multiple ethernet frames 348 * into a single USB transfer 349 */ 350 static struct sk_buff *eem_wrap(struct gether *port, struct sk_buff *skb) 351 { 352 struct sk_buff *skb2 = NULL; 353 struct usb_ep *in = port->in_ep; 354 int padlen = 0; 355 u16 len = skb->len; 356 357 int headroom = skb_headroom(skb); 358 int tailroom = skb_tailroom(skb); 359 360 /* When (len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) is 0, 361 * stick two bytes of zero-length EEM packet on the end. 362 */ 363 if (((len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) == 0) 364 padlen += 2; 365 366 if ((tailroom >= (ETH_FCS_LEN + padlen)) && 367 (headroom >= EEM_HLEN) && !skb_cloned(skb)) 368 goto done; 369 370 skb2 = skb_copy_expand(skb, EEM_HLEN, ETH_FCS_LEN + padlen, GFP_ATOMIC); 371 dev_kfree_skb_any(skb); 372 skb = skb2; 373 if (!skb) 374 return skb; 375 376 done: 377 /* use the "no CRC" option */ 378 put_unaligned_be32(0xdeadbeef, skb_put(skb, 4)); 379 380 /* EEM packet header format: 381 * b0..13: length of ethernet frame 382 * b14: bmCRC (0 == sentinel CRC) 383 * b15: bmType (0 == data) 384 */ 385 len = skb->len; 386 put_unaligned_le16(len & 0x3FFF, skb_push(skb, 2)); 387 388 /* add a zero-length EEM packet, if needed */ 389 if (padlen) 390 put_unaligned_le16(0, skb_put(skb, 2)); 391 392 return skb; 393 } 394 395 /* 396 * Remove the EEM header. Note that there can be many EEM packets in a single 397 * USB transfer, so we need to break them out and handle them independently. 398 */ 399 static int eem_unwrap(struct gether *port, 400 struct sk_buff *skb, 401 struct sk_buff_head *list) 402 { 403 struct usb_composite_dev *cdev = port->func.config->cdev; 404 int status = 0; 405 406 do { 407 struct sk_buff *skb2; 408 u16 header; 409 u16 len = 0; 410 411 if (skb->len < EEM_HLEN) { 412 status = -EINVAL; 413 DBG(cdev, "invalid EEM header\n"); 414 goto error; 415 } 416 417 /* remove the EEM header */ 418 header = get_unaligned_le16(skb->data); 419 skb_pull(skb, EEM_HLEN); 420 421 /* EEM packet header format: 422 * b0..14: EEM type dependent (data or command) 423 * b15: bmType (0 == data, 1 == command) 424 */ 425 if (header & BIT(15)) { 426 struct usb_request *req = cdev->req; 427 u16 bmEEMCmd; 428 429 /* EEM command packet format: 430 * b0..10: bmEEMCmdParam 431 * b11..13: bmEEMCmd 432 * b14: reserved (must be zero) 433 * b15: bmType (1 == command) 434 */ 435 if (header & BIT(14)) 436 continue; 437 438 bmEEMCmd = (header >> 11) & 0x7; 439 switch (bmEEMCmd) { 440 case 0: /* echo */ 441 len = header & 0x7FF; 442 if (skb->len < len) { 443 status = -EOVERFLOW; 444 goto error; 445 } 446 447 skb2 = skb_clone(skb, GFP_ATOMIC); 448 if (unlikely(!skb2)) { 449 DBG(cdev, "EEM echo response error\n"); 450 goto next; 451 } 452 skb_trim(skb2, len); 453 put_unaligned_le16(BIT(15) | BIT(11) | len, 454 skb_push(skb2, 2)); 455 skb_copy_bits(skb2, 0, req->buf, skb2->len); 456 req->length = skb2->len; 457 req->complete = eem_cmd_complete; 458 req->zero = 1; 459 req->context = skb2; 460 if (usb_ep_queue(port->in_ep, req, GFP_ATOMIC)) 461 DBG(cdev, "echo response queue fail\n"); 462 break; 463 464 case 1: /* echo response */ 465 case 2: /* suspend hint */ 466 case 3: /* response hint */ 467 case 4: /* response complete hint */ 468 case 5: /* tickle */ 469 default: /* reserved */ 470 continue; 471 } 472 } else { 473 u32 crc, crc2; 474 struct sk_buff *skb3; 475 476 /* check for zero-length EEM packet */ 477 if (header == 0) 478 continue; 479 480 /* EEM data packet format: 481 * b0..13: length of ethernet frame 482 * b14: bmCRC (0 == sentinel, 1 == calculated) 483 * b15: bmType (0 == data) 484 */ 485 len = header & 0x3FFF; 486 if ((skb->len < len) 487 || (len < (ETH_HLEN + ETH_FCS_LEN))) { 488 status = -EINVAL; 489 goto error; 490 } 491 492 /* validate CRC */ 493 if (header & BIT(14)) { 494 crc = get_unaligned_le32(skb->data + len 495 - ETH_FCS_LEN); 496 crc2 = ~crc32_le(~0, 497 skb->data, len - ETH_FCS_LEN); 498 } else { 499 crc = get_unaligned_be32(skb->data + len 500 - ETH_FCS_LEN); 501 crc2 = 0xdeadbeef; 502 } 503 if (crc != crc2) { 504 DBG(cdev, "invalid EEM CRC\n"); 505 goto next; 506 } 507 508 skb2 = skb_clone(skb, GFP_ATOMIC); 509 if (unlikely(!skb2)) { 510 DBG(cdev, "unable to unframe EEM packet\n"); 511 continue; 512 } 513 skb_trim(skb2, len - ETH_FCS_LEN); 514 515 skb3 = skb_copy_expand(skb2, 516 NET_IP_ALIGN, 517 0, 518 GFP_ATOMIC); 519 if (unlikely(!skb3)) { 520 DBG(cdev, "unable to realign EEM packet\n"); 521 dev_kfree_skb_any(skb2); 522 continue; 523 } 524 dev_kfree_skb_any(skb2); 525 skb_queue_tail(list, skb3); 526 } 527 next: 528 skb_pull(skb, len); 529 } while (skb->len); 530 531 error: 532 dev_kfree_skb_any(skb); 533 return status; 534 } 535 536 static inline struct f_eem_opts *to_f_eem_opts(struct config_item *item) 537 { 538 return container_of(to_config_group(item), struct f_eem_opts, 539 func_inst.group); 540 } 541 542 /* f_eem_item_ops */ 543 USB_ETHERNET_CONFIGFS_ITEM(eem); 544 545 /* f_eem_opts_dev_addr */ 546 USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(eem); 547 548 /* f_eem_opts_host_addr */ 549 USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(eem); 550 551 /* f_eem_opts_qmult */ 552 USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(eem); 553 554 /* f_eem_opts_ifname */ 555 USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(eem); 556 557 static struct configfs_attribute *eem_attrs[] = { 558 &f_eem_opts_dev_addr.attr, 559 &f_eem_opts_host_addr.attr, 560 &f_eem_opts_qmult.attr, 561 &f_eem_opts_ifname.attr, 562 NULL, 563 }; 564 565 static struct config_item_type eem_func_type = { 566 .ct_item_ops = &eem_item_ops, 567 .ct_attrs = eem_attrs, 568 .ct_owner = THIS_MODULE, 569 }; 570 571 static void eem_free_inst(struct usb_function_instance *f) 572 { 573 struct f_eem_opts *opts; 574 575 opts = container_of(f, struct f_eem_opts, func_inst); 576 if (opts->bound) 577 gether_cleanup(netdev_priv(opts->net)); 578 else 579 free_netdev(opts->net); 580 kfree(opts); 581 } 582 583 static struct usb_function_instance *eem_alloc_inst(void) 584 { 585 struct f_eem_opts *opts; 586 587 opts = kzalloc(sizeof(*opts), GFP_KERNEL); 588 if (!opts) 589 return ERR_PTR(-ENOMEM); 590 mutex_init(&opts->lock); 591 opts->func_inst.free_func_inst = eem_free_inst; 592 opts->net = gether_setup_default(); 593 if (IS_ERR(opts->net)) { 594 struct net_device *net = opts->net; 595 kfree(opts); 596 return ERR_CAST(net); 597 } 598 599 config_group_init_type_name(&opts->func_inst.group, "", &eem_func_type); 600 601 return &opts->func_inst; 602 } 603 604 static void eem_free(struct usb_function *f) 605 { 606 struct f_eem *eem; 607 struct f_eem_opts *opts; 608 609 eem = func_to_eem(f); 610 opts = container_of(f->fi, struct f_eem_opts, func_inst); 611 kfree(eem); 612 mutex_lock(&opts->lock); 613 opts->refcnt--; 614 mutex_unlock(&opts->lock); 615 } 616 617 static void eem_unbind(struct usb_configuration *c, struct usb_function *f) 618 { 619 DBG(c->cdev, "eem unbind\n"); 620 621 usb_free_all_descriptors(f); 622 } 623 624 static struct usb_function *eem_alloc(struct usb_function_instance *fi) 625 { 626 struct f_eem *eem; 627 struct f_eem_opts *opts; 628 629 /* allocate and initialize one new instance */ 630 eem = kzalloc(sizeof(*eem), GFP_KERNEL); 631 if (!eem) 632 return ERR_PTR(-ENOMEM); 633 634 opts = container_of(fi, struct f_eem_opts, func_inst); 635 mutex_lock(&opts->lock); 636 opts->refcnt++; 637 638 eem->port.ioport = netdev_priv(opts->net); 639 mutex_unlock(&opts->lock); 640 eem->port.cdc_filter = DEFAULT_FILTER; 641 642 eem->port.func.name = "cdc_eem"; 643 /* descriptors are per-instance copies */ 644 eem->port.func.bind = eem_bind; 645 eem->port.func.unbind = eem_unbind; 646 eem->port.func.set_alt = eem_set_alt; 647 eem->port.func.setup = eem_setup; 648 eem->port.func.disable = eem_disable; 649 eem->port.func.free_func = eem_free; 650 eem->port.wrap = eem_wrap; 651 eem->port.unwrap = eem_unwrap; 652 eem->port.header_len = EEM_HLEN; 653 654 return &eem->port.func; 655 } 656 657 DECLARE_USB_FUNCTION_INIT(eem, eem_alloc_inst, eem_alloc); 658 MODULE_LICENSE("GPL"); 659 MODULE_AUTHOR("David Brownell"); 660