1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * f_eem.c -- USB CDC Ethernet (EEM) link function driver 4 * 5 * Copyright (C) 2003-2005,2008 David Brownell 6 * Copyright (C) 2008 Nokia Corporation 7 * Copyright (C) 2009 EF Johnson Technologies 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/module.h> 12 #include <linux/device.h> 13 #include <linux/etherdevice.h> 14 #include <linux/crc32.h> 15 #include <linux/slab.h> 16 17 #include "u_ether.h" 18 #include "u_ether_configfs.h" 19 #include "u_eem.h" 20 21 #define EEM_HLEN 2 22 23 /* 24 * This function is a "CDC Ethernet Emulation Model" (CDC EEM) 25 * Ethernet link. 26 */ 27 28 struct f_eem { 29 struct gether port; 30 u8 ctrl_id; 31 }; 32 33 struct in_context { 34 struct sk_buff *skb; 35 struct usb_ep *ep; 36 }; 37 38 static inline struct f_eem *func_to_eem(struct usb_function *f) 39 { 40 return container_of(f, struct f_eem, port.func); 41 } 42 43 /*-------------------------------------------------------------------------*/ 44 45 /* interface descriptor: */ 46 47 static struct usb_interface_descriptor eem_intf = { 48 .bLength = sizeof eem_intf, 49 .bDescriptorType = USB_DT_INTERFACE, 50 51 /* .bInterfaceNumber = DYNAMIC */ 52 .bNumEndpoints = 2, 53 .bInterfaceClass = USB_CLASS_COMM, 54 .bInterfaceSubClass = USB_CDC_SUBCLASS_EEM, 55 .bInterfaceProtocol = USB_CDC_PROTO_EEM, 56 /* .iInterface = DYNAMIC */ 57 }; 58 59 /* full speed support: */ 60 61 static struct usb_endpoint_descriptor eem_fs_in_desc = { 62 .bLength = USB_DT_ENDPOINT_SIZE, 63 .bDescriptorType = USB_DT_ENDPOINT, 64 65 .bEndpointAddress = USB_DIR_IN, 66 .bmAttributes = USB_ENDPOINT_XFER_BULK, 67 }; 68 69 static struct usb_endpoint_descriptor eem_fs_out_desc = { 70 .bLength = USB_DT_ENDPOINT_SIZE, 71 .bDescriptorType = USB_DT_ENDPOINT, 72 73 .bEndpointAddress = USB_DIR_OUT, 74 .bmAttributes = USB_ENDPOINT_XFER_BULK, 75 }; 76 77 static struct usb_descriptor_header *eem_fs_function[] = { 78 /* CDC EEM control descriptors */ 79 (struct usb_descriptor_header *) &eem_intf, 80 (struct usb_descriptor_header *) &eem_fs_in_desc, 81 (struct usb_descriptor_header *) &eem_fs_out_desc, 82 NULL, 83 }; 84 85 /* high speed support: */ 86 87 static struct usb_endpoint_descriptor eem_hs_in_desc = { 88 .bLength = USB_DT_ENDPOINT_SIZE, 89 .bDescriptorType = USB_DT_ENDPOINT, 90 91 .bEndpointAddress = USB_DIR_IN, 92 .bmAttributes = USB_ENDPOINT_XFER_BULK, 93 .wMaxPacketSize = cpu_to_le16(512), 94 }; 95 96 static struct usb_endpoint_descriptor eem_hs_out_desc = { 97 .bLength = USB_DT_ENDPOINT_SIZE, 98 .bDescriptorType = USB_DT_ENDPOINT, 99 100 .bEndpointAddress = USB_DIR_OUT, 101 .bmAttributes = USB_ENDPOINT_XFER_BULK, 102 .wMaxPacketSize = cpu_to_le16(512), 103 }; 104 105 static struct usb_descriptor_header *eem_hs_function[] = { 106 /* CDC EEM control descriptors */ 107 (struct usb_descriptor_header *) &eem_intf, 108 (struct usb_descriptor_header *) &eem_hs_in_desc, 109 (struct usb_descriptor_header *) &eem_hs_out_desc, 110 NULL, 111 }; 112 113 /* super speed support: */ 114 115 static struct usb_endpoint_descriptor eem_ss_in_desc = { 116 .bLength = USB_DT_ENDPOINT_SIZE, 117 .bDescriptorType = USB_DT_ENDPOINT, 118 119 .bEndpointAddress = USB_DIR_IN, 120 .bmAttributes = USB_ENDPOINT_XFER_BULK, 121 .wMaxPacketSize = cpu_to_le16(1024), 122 }; 123 124 static struct usb_endpoint_descriptor eem_ss_out_desc = { 125 .bLength = USB_DT_ENDPOINT_SIZE, 126 .bDescriptorType = USB_DT_ENDPOINT, 127 128 .bEndpointAddress = USB_DIR_OUT, 129 .bmAttributes = USB_ENDPOINT_XFER_BULK, 130 .wMaxPacketSize = cpu_to_le16(1024), 131 }; 132 133 static struct usb_ss_ep_comp_descriptor eem_ss_bulk_comp_desc = { 134 .bLength = sizeof eem_ss_bulk_comp_desc, 135 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP, 136 137 /* the following 2 values can be tweaked if necessary */ 138 /* .bMaxBurst = 0, */ 139 /* .bmAttributes = 0, */ 140 }; 141 142 static struct usb_descriptor_header *eem_ss_function[] = { 143 /* CDC EEM control descriptors */ 144 (struct usb_descriptor_header *) &eem_intf, 145 (struct usb_descriptor_header *) &eem_ss_in_desc, 146 (struct usb_descriptor_header *) &eem_ss_bulk_comp_desc, 147 (struct usb_descriptor_header *) &eem_ss_out_desc, 148 (struct usb_descriptor_header *) &eem_ss_bulk_comp_desc, 149 NULL, 150 }; 151 152 /* string descriptors: */ 153 154 static struct usb_string eem_string_defs[] = { 155 [0].s = "CDC Ethernet Emulation Model (EEM)", 156 { } /* end of list */ 157 }; 158 159 static struct usb_gadget_strings eem_string_table = { 160 .language = 0x0409, /* en-us */ 161 .strings = eem_string_defs, 162 }; 163 164 static struct usb_gadget_strings *eem_strings[] = { 165 &eem_string_table, 166 NULL, 167 }; 168 169 /*-------------------------------------------------------------------------*/ 170 171 static int eem_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl) 172 { 173 struct usb_composite_dev *cdev = f->config->cdev; 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 -EOPNOTSUPP; 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 /* support all relevant hardware speeds... we expect that when 300 * hardware is dual speed, all bulk-capable endpoints work at 301 * both speeds 302 */ 303 eem_hs_in_desc.bEndpointAddress = eem_fs_in_desc.bEndpointAddress; 304 eem_hs_out_desc.bEndpointAddress = eem_fs_out_desc.bEndpointAddress; 305 306 eem_ss_in_desc.bEndpointAddress = eem_fs_in_desc.bEndpointAddress; 307 eem_ss_out_desc.bEndpointAddress = eem_fs_out_desc.bEndpointAddress; 308 309 status = usb_assign_descriptors(f, eem_fs_function, eem_hs_function, 310 eem_ss_function, eem_ss_function); 311 if (status) 312 goto fail; 313 314 DBG(cdev, "CDC Ethernet (EEM): %s speed IN/%s OUT/%s\n", 315 gadget_is_superspeed(c->cdev->gadget) ? "super" : 316 gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full", 317 eem->port.in_ep->name, eem->port.out_ep->name); 318 return 0; 319 320 fail: 321 ERROR(cdev, "%s: can't bind, err %d\n", f->name, status); 322 323 return status; 324 } 325 326 static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req) 327 { 328 struct in_context *ctx = req->context; 329 330 dev_kfree_skb_any(ctx->skb); 331 kfree(req->buf); 332 usb_ep_free_request(ctx->ep, req); 333 kfree(ctx); 334 } 335 336 /* 337 * Add the EEM header and ethernet checksum. 338 * We currently do not attempt to put multiple ethernet frames 339 * into a single USB transfer 340 */ 341 static struct sk_buff *eem_wrap(struct gether *port, struct sk_buff *skb) 342 { 343 struct sk_buff *skb2 = NULL; 344 struct usb_ep *in = port->in_ep; 345 int headroom, tailroom, padlen = 0; 346 u16 len; 347 348 if (!skb) 349 return NULL; 350 351 len = skb->len; 352 headroom = skb_headroom(skb); 353 tailroom = skb_tailroom(skb); 354 355 /* When (len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) is 0, 356 * stick two bytes of zero-length EEM packet on the end. 357 */ 358 if (((len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) == 0) 359 padlen += 2; 360 361 if ((tailroom >= (ETH_FCS_LEN + padlen)) && 362 (headroom >= EEM_HLEN) && !skb_cloned(skb)) 363 goto done; 364 365 skb2 = skb_copy_expand(skb, EEM_HLEN, ETH_FCS_LEN + padlen, GFP_ATOMIC); 366 dev_kfree_skb_any(skb); 367 skb = skb2; 368 if (!skb) 369 return skb; 370 371 done: 372 /* use the "no CRC" option */ 373 put_unaligned_be32(0xdeadbeef, skb_put(skb, 4)); 374 375 /* EEM packet header format: 376 * b0..13: length of ethernet frame 377 * b14: bmCRC (0 == sentinel CRC) 378 * b15: bmType (0 == data) 379 */ 380 len = skb->len; 381 put_unaligned_le16(len & 0x3FFF, skb_push(skb, 2)); 382 383 /* add a zero-length EEM packet, if needed */ 384 if (padlen) 385 put_unaligned_le16(0, skb_put(skb, 2)); 386 387 return skb; 388 } 389 390 /* 391 * Remove the EEM header. Note that there can be many EEM packets in a single 392 * USB transfer, so we need to break them out and handle them independently. 393 */ 394 static int eem_unwrap(struct gether *port, 395 struct sk_buff *skb, 396 struct sk_buff_head *list) 397 { 398 struct usb_composite_dev *cdev = port->func.config->cdev; 399 int status = 0; 400 401 do { 402 struct sk_buff *skb2; 403 u16 header; 404 u16 len = 0; 405 406 if (skb->len < EEM_HLEN) { 407 status = -EINVAL; 408 DBG(cdev, "invalid EEM header\n"); 409 goto error; 410 } 411 412 /* remove the EEM header */ 413 header = get_unaligned_le16(skb->data); 414 skb_pull(skb, EEM_HLEN); 415 416 /* EEM packet header format: 417 * b0..14: EEM type dependent (data or command) 418 * b15: bmType (0 == data, 1 == command) 419 */ 420 if (header & BIT(15)) { 421 struct usb_request *req; 422 struct in_context *ctx; 423 struct usb_ep *ep; 424 u16 bmEEMCmd; 425 426 /* EEM command packet format: 427 * b0..10: bmEEMCmdParam 428 * b11..13: bmEEMCmd 429 * b14: reserved (must be zero) 430 * b15: bmType (1 == command) 431 */ 432 if (header & BIT(14)) 433 continue; 434 435 bmEEMCmd = (header >> 11) & 0x7; 436 switch (bmEEMCmd) { 437 case 0: /* echo */ 438 len = header & 0x7FF; 439 if (skb->len < len) { 440 status = -EOVERFLOW; 441 goto error; 442 } 443 444 skb2 = skb_clone(skb, GFP_ATOMIC); 445 if (unlikely(!skb2)) { 446 DBG(cdev, "EEM echo response error\n"); 447 goto next; 448 } 449 skb_trim(skb2, len); 450 put_unaligned_le16(BIT(15) | BIT(11) | len, 451 skb_push(skb2, 2)); 452 453 ep = port->in_ep; 454 req = usb_ep_alloc_request(ep, GFP_ATOMIC); 455 if (!req) { 456 dev_kfree_skb_any(skb2); 457 goto next; 458 } 459 460 req->buf = kmalloc(skb2->len, GFP_KERNEL); 461 if (!req->buf) { 462 usb_ep_free_request(ep, req); 463 dev_kfree_skb_any(skb2); 464 goto next; 465 } 466 467 ctx = kmalloc(sizeof(*ctx), GFP_KERNEL); 468 if (!ctx) { 469 kfree(req->buf); 470 usb_ep_free_request(ep, req); 471 dev_kfree_skb_any(skb2); 472 goto next; 473 } 474 ctx->skb = skb2; 475 ctx->ep = ep; 476 477 skb_copy_bits(skb2, 0, req->buf, skb2->len); 478 req->length = skb2->len; 479 req->complete = eem_cmd_complete; 480 req->zero = 1; 481 req->context = ctx; 482 if (usb_ep_queue(port->in_ep, req, GFP_ATOMIC)) 483 DBG(cdev, "echo response queue fail\n"); 484 break; 485 486 case 1: /* echo response */ 487 case 2: /* suspend hint */ 488 case 3: /* response hint */ 489 case 4: /* response complete hint */ 490 case 5: /* tickle */ 491 default: /* reserved */ 492 continue; 493 } 494 } else { 495 u32 crc, crc2; 496 struct sk_buff *skb3; 497 498 /* check for zero-length EEM packet */ 499 if (header == 0) 500 continue; 501 502 /* EEM data packet format: 503 * b0..13: length of ethernet frame 504 * b14: bmCRC (0 == sentinel, 1 == calculated) 505 * b15: bmType (0 == data) 506 */ 507 len = header & 0x3FFF; 508 if ((skb->len < len) 509 || (len < (ETH_HLEN + ETH_FCS_LEN))) { 510 status = -EINVAL; 511 goto error; 512 } 513 514 /* validate CRC */ 515 if (header & BIT(14)) { 516 crc = get_unaligned_le32(skb->data + len 517 - ETH_FCS_LEN); 518 crc2 = ~crc32_le(~0, 519 skb->data, len - ETH_FCS_LEN); 520 } else { 521 crc = get_unaligned_be32(skb->data + len 522 - ETH_FCS_LEN); 523 crc2 = 0xdeadbeef; 524 } 525 if (crc != crc2) { 526 DBG(cdev, "invalid EEM CRC\n"); 527 goto next; 528 } 529 530 skb2 = skb_clone(skb, GFP_ATOMIC); 531 if (unlikely(!skb2)) { 532 DBG(cdev, "unable to unframe EEM packet\n"); 533 goto next; 534 } 535 skb_trim(skb2, len - ETH_FCS_LEN); 536 537 skb3 = skb_copy_expand(skb2, 538 NET_IP_ALIGN, 539 0, 540 GFP_ATOMIC); 541 if (unlikely(!skb3)) { 542 dev_kfree_skb_any(skb2); 543 goto next; 544 } 545 dev_kfree_skb_any(skb2); 546 skb_queue_tail(list, skb3); 547 } 548 next: 549 skb_pull(skb, len); 550 } while (skb->len); 551 552 error: 553 dev_kfree_skb_any(skb); 554 return status; 555 } 556 557 static inline struct f_eem_opts *to_f_eem_opts(struct config_item *item) 558 { 559 return container_of(to_config_group(item), struct f_eem_opts, 560 func_inst.group); 561 } 562 563 /* f_eem_item_ops */ 564 USB_ETHERNET_CONFIGFS_ITEM(eem); 565 566 /* f_eem_opts_dev_addr */ 567 USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(eem); 568 569 /* f_eem_opts_host_addr */ 570 USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(eem); 571 572 /* f_eem_opts_qmult */ 573 USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(eem); 574 575 /* f_eem_opts_ifname */ 576 USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(eem); 577 578 static struct configfs_attribute *eem_attrs[] = { 579 &eem_opts_attr_dev_addr, 580 &eem_opts_attr_host_addr, 581 &eem_opts_attr_qmult, 582 &eem_opts_attr_ifname, 583 NULL, 584 }; 585 586 static const struct config_item_type eem_func_type = { 587 .ct_item_ops = &eem_item_ops, 588 .ct_attrs = eem_attrs, 589 .ct_owner = THIS_MODULE, 590 }; 591 592 static void eem_free_inst(struct usb_function_instance *f) 593 { 594 struct f_eem_opts *opts; 595 596 opts = container_of(f, struct f_eem_opts, func_inst); 597 if (opts->bound) 598 gether_cleanup(netdev_priv(opts->net)); 599 else 600 free_netdev(opts->net); 601 kfree(opts); 602 } 603 604 static struct usb_function_instance *eem_alloc_inst(void) 605 { 606 struct f_eem_opts *opts; 607 608 opts = kzalloc(sizeof(*opts), GFP_KERNEL); 609 if (!opts) 610 return ERR_PTR(-ENOMEM); 611 mutex_init(&opts->lock); 612 opts->func_inst.free_func_inst = eem_free_inst; 613 opts->net = gether_setup_default(); 614 if (IS_ERR(opts->net)) { 615 struct net_device *net = opts->net; 616 kfree(opts); 617 return ERR_CAST(net); 618 } 619 620 config_group_init_type_name(&opts->func_inst.group, "", &eem_func_type); 621 622 return &opts->func_inst; 623 } 624 625 static void eem_free(struct usb_function *f) 626 { 627 struct f_eem *eem; 628 struct f_eem_opts *opts; 629 630 eem = func_to_eem(f); 631 opts = container_of(f->fi, struct f_eem_opts, func_inst); 632 kfree(eem); 633 mutex_lock(&opts->lock); 634 opts->refcnt--; 635 mutex_unlock(&opts->lock); 636 } 637 638 static void eem_unbind(struct usb_configuration *c, struct usb_function *f) 639 { 640 DBG(c->cdev, "eem unbind\n"); 641 642 usb_free_all_descriptors(f); 643 } 644 645 static struct usb_function *eem_alloc(struct usb_function_instance *fi) 646 { 647 struct f_eem *eem; 648 struct f_eem_opts *opts; 649 650 /* allocate and initialize one new instance */ 651 eem = kzalloc(sizeof(*eem), GFP_KERNEL); 652 if (!eem) 653 return ERR_PTR(-ENOMEM); 654 655 opts = container_of(fi, struct f_eem_opts, func_inst); 656 mutex_lock(&opts->lock); 657 opts->refcnt++; 658 659 eem->port.ioport = netdev_priv(opts->net); 660 mutex_unlock(&opts->lock); 661 eem->port.cdc_filter = DEFAULT_FILTER; 662 663 eem->port.func.name = "cdc_eem"; 664 /* descriptors are per-instance copies */ 665 eem->port.func.bind = eem_bind; 666 eem->port.func.unbind = eem_unbind; 667 eem->port.func.set_alt = eem_set_alt; 668 eem->port.func.setup = eem_setup; 669 eem->port.func.disable = eem_disable; 670 eem->port.func.free_func = eem_free; 671 eem->port.wrap = eem_wrap; 672 eem->port.unwrap = eem_unwrap; 673 eem->port.header_len = EEM_HLEN; 674 675 return &eem->port.func; 676 } 677 678 DECLARE_USB_FUNCTION_INIT(eem, eem_alloc_inst, eem_alloc); 679 MODULE_LICENSE("GPL"); 680 MODULE_AUTHOR("David Brownell"); 681