drivers/usb/gadget/function/f_ecm.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * f_ecm.c -- USB CDC Ethernet (ECM) link function driver
   4  *
   5  * Copyright (C) 2003-2005,2008 David Brownell
   6  * Copyright (C) 2008 Nokia Corporation
   7  */
   8
   9 /* #define VERBOSE_DEBUG */
  10
  11 #include <linux/slab.h>
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/device.h>
  15 #include <linux/etherdevice.h>
  16
  17 #include "u_ether.h"
  18 #include "u_ether_configfs.h"
  19 #include "u_ecm.h"
  20
  21
  22 /*
  23  * This function is a "CDC Ethernet Networking Control Model" (CDC ECM)
  24  * Ethernet link.  The data transfer model is simple (packets sent and
  25  * received over bulk endpoints using normal short packet termination),
  26  * and the control model exposes various data and optional notifications.
  27  *
  28  * ECM is well standardized and (except for Microsoft) supported by most
  29  * operating systems with USB host support.  It's the preferred interop
  30  * solution for Ethernet over USB, at least for firmware based solutions.
  31  * (Hardware solutions tend to be more minimalist.)  A newer and simpler
  32  * "Ethernet Emulation Model" (CDC EEM) hasn't yet caught on.
  33  *
  34  * Note that ECM requires the use of "alternate settings" for its data
  35  * interface.  This means that the set_alt() method has real work to do,
  36  * and also means that a get_alt() method is required.
  37  */
  38
  39
  40 enum ecm_notify_state {
  41         ECM_NOTIFY_NONE,                /* don't notify */
  42         ECM_NOTIFY_CONNECT,             /* issue CONNECT next */
  43         ECM_NOTIFY_SPEED,               /* issue SPEED_CHANGE next */
  44 };
  45
  46 struct f_ecm {
  47         struct gether                   port;
  48         u8                              ctrl_id, data_id;
  49
  50         char                            ethaddr[14];
  51
  52         struct usb_ep                   *notify;
  53         struct usb_request              *notify_req;
  54         u8                              notify_state;
  55         bool                            is_open;
  56
  57         /* FIXME is_open needs some irq-ish locking
  58          * ... possibly the same as port.ioport
  59          */
  60 };
  61
  62 static inline struct f_ecm *func_to_ecm(struct usb_function *f)
  63 {
  64         return container_of(f, struct f_ecm, port.func);
  65 }
  66
  67 /* peak (theoretical) bulk transfer rate in bits-per-second */
  68 static inline unsigned ecm_bitrate(struct usb_gadget *g)
  69 {
  70         if (gadget_is_superspeed(g) && g->speed == USB_SPEED_SUPER)
  71                 return 13 * 1024 * 8 * 1000 * 8;
  72         else if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
  73                 return 13 * 512 * 8 * 1000 * 8;
  74         else
  75                 return 19 * 64 * 1 * 1000 * 8;
  76 }
  77
  78 /*-------------------------------------------------------------------------*/
  79
  80 /*
  81  * Include the status endpoint if we can, even though it's optional.
  82  *
  83  * Use wMaxPacketSize big enough to fit CDC_NOTIFY_SPEED_CHANGE in one
  84  * packet, to simplify cancellation; and a big transfer interval, to
  85  * waste less bandwidth.
  86  *
  87  * Some drivers (like Linux 2.4 cdc-ether!) "need" it to exist even
  88  * if they ignore the connect/disconnect notifications that real aether
  89  * can provide.  More advanced cdc configurations might want to support
  90  * encapsulated commands (vendor-specific, using control-OUT).
  91  */
  92
  93 #define ECM_STATUS_INTERVAL_MS          32
  94 #define ECM_STATUS_BYTECOUNT            16      /* 8 byte header + data */
  95
  96
  97 /* interface descriptor: */
  98
  99 static struct usb_interface_assoc_descriptor
 100 ecm_iad_descriptor = {
 101         .bLength =              sizeof ecm_iad_descriptor,
 102         .bDescriptorType =      USB_DT_INTERFACE_ASSOCIATION,
 103
 104         /* .bFirstInterface =   DYNAMIC, */
 105         .bInterfaceCount =      2,      /* control + data */
 106         .bFunctionClass =       USB_CLASS_COMM,
 107         .bFunctionSubClass =    USB_CDC_SUBCLASS_ETHERNET,
 108         .bFunctionProtocol =    USB_CDC_PROTO_NONE,
 109         /* .iFunction =         DYNAMIC */
 110 };
 111
 112
 113 static struct usb_interface_descriptor ecm_control_intf = {
 114         .bLength =              sizeof ecm_control_intf,
 115         .bDescriptorType =      USB_DT_INTERFACE,
 116
 117         /* .bInterfaceNumber = DYNAMIC */
 118         /* status endpoint is optional; this could be patched later */
 119         .bNumEndpoints =        1,
 120         .bInterfaceClass =      USB_CLASS_COMM,
 121         .bInterfaceSubClass =   USB_CDC_SUBCLASS_ETHERNET,
 122         .bInterfaceProtocol =   USB_CDC_PROTO_NONE,
 123         /* .iInterface = DYNAMIC */
 124 };
 125
 126 static struct usb_cdc_header_desc ecm_header_desc = {
 127         .bLength =              sizeof ecm_header_desc,
 128         .bDescriptorType =      USB_DT_CS_INTERFACE,
 129         .bDescriptorSubType =   USB_CDC_HEADER_TYPE,
 130
 131         .bcdCDC =               cpu_to_le16(0x0110),
 132 };
 133
 134 static struct usb_cdc_union_desc ecm_union_desc = {
 135         .bLength =              sizeof(ecm_union_desc),
 136         .bDescriptorType =      USB_DT_CS_INTERFACE,
 137         .bDescriptorSubType =   USB_CDC_UNION_TYPE,
 138         /* .bMasterInterface0 = DYNAMIC */
 139         /* .bSlaveInterface0 =  DYNAMIC */
 140 };
 141
 142 static struct usb_cdc_ether_desc ecm_desc = {
 143         .bLength =              sizeof ecm_desc,
 144         .bDescriptorType =      USB_DT_CS_INTERFACE,
 145         .bDescriptorSubType =   USB_CDC_ETHERNET_TYPE,
 146
 147         /* this descriptor actually adds value, surprise! */
 148         /* .iMACAddress = DYNAMIC */
 149         .bmEthernetStatistics = cpu_to_le32(0), /* no statistics */
 150         .wMaxSegmentSize =      cpu_to_le16(ETH_FRAME_LEN),
 151         .wNumberMCFilters =     cpu_to_le16(0),
 152         .bNumberPowerFilters =  0,
 153 };
 154
 155 /* the default data interface has no endpoints ... */
 156
 157 static struct usb_interface_descriptor ecm_data_nop_intf = {
 158         .bLength =              sizeof ecm_data_nop_intf,
 159         .bDescriptorType =      USB_DT_INTERFACE,
 160
 161         .bInterfaceNumber =     1,
 162         .bAlternateSetting =    0,
 163         .bNumEndpoints =        0,
 164         .bInterfaceClass =      USB_CLASS_CDC_DATA,
 165         .bInterfaceSubClass =   0,
 166         .bInterfaceProtocol =   0,
 167         /* .iInterface = DYNAMIC */
 168 };
 169
 170 /* ... but the "real" data interface has two bulk endpoints */
 171
 172 static struct usb_interface_descriptor ecm_data_intf = {
 173         .bLength =              sizeof ecm_data_intf,
 174         .bDescriptorType =      USB_DT_INTERFACE,
 175
 176         .bInterfaceNumber =     1,
 177         .bAlternateSetting =    1,
 178         .bNumEndpoints =        2,
 179         .bInterfaceClass =      USB_CLASS_CDC_DATA,
 180         .bInterfaceSubClass =   0,
 181         .bInterfaceProtocol =   0,
 182         /* .iInterface = DYNAMIC */
 183 };
 184
 185 /* full speed support: */
 186
 187 static struct usb_endpoint_descriptor fs_ecm_notify_desc = {
 188         .bLength =              USB_DT_ENDPOINT_SIZE,
 189         .bDescriptorType =      USB_DT_ENDPOINT,
 190
 191         .bEndpointAddress =     USB_DIR_IN,
 192         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 193         .wMaxPacketSize =       cpu_to_le16(ECM_STATUS_BYTECOUNT),
 194         .bInterval =            ECM_STATUS_INTERVAL_MS,
 195 };
 196
 197 static struct usb_endpoint_descriptor fs_ecm_in_desc = {
 198         .bLength =              USB_DT_ENDPOINT_SIZE,
 199         .bDescriptorType =      USB_DT_ENDPOINT,
 200
 201         .bEndpointAddress =     USB_DIR_IN,
 202         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 203 };
 204
 205 static struct usb_endpoint_descriptor fs_ecm_out_desc = {
 206         .bLength =              USB_DT_ENDPOINT_SIZE,
 207         .bDescriptorType =      USB_DT_ENDPOINT,
 208
 209         .bEndpointAddress =     USB_DIR_OUT,
 210         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 211 };
 212
 213 static struct usb_descriptor_header *ecm_fs_function[] = {
 214         /* CDC ECM control descriptors */
 215         (struct usb_descriptor_header *) &ecm_iad_descriptor,
 216         (struct usb_descriptor_header *) &ecm_control_intf,
 217         (struct usb_descriptor_header *) &ecm_header_desc,
 218         (struct usb_descriptor_header *) &ecm_union_desc,
 219         (struct usb_descriptor_header *) &ecm_desc,
 220
 221         /* NOTE: status endpoint might need to be removed */
 222         (struct usb_descriptor_header *) &fs_ecm_notify_desc,
 223
 224         /* data interface, altsettings 0 and 1 */
 225         (struct usb_descriptor_header *) &ecm_data_nop_intf,
 226         (struct usb_descriptor_header *) &ecm_data_intf,
 227         (struct usb_descriptor_header *) &fs_ecm_in_desc,
 228         (struct usb_descriptor_header *) &fs_ecm_out_desc,
 229         NULL,
 230 };
 231
 232 /* high speed support: */
 233
 234 static struct usb_endpoint_descriptor hs_ecm_notify_desc = {
 235         .bLength =              USB_DT_ENDPOINT_SIZE,
 236         .bDescriptorType =      USB_DT_ENDPOINT,
 237
 238         .bEndpointAddress =     USB_DIR_IN,
 239         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 240         .wMaxPacketSize =       cpu_to_le16(ECM_STATUS_BYTECOUNT),
 241         .bInterval =            USB_MS_TO_HS_INTERVAL(ECM_STATUS_INTERVAL_MS),
 242 };
 243
 244 static struct usb_endpoint_descriptor hs_ecm_in_desc = {
 245         .bLength =              USB_DT_ENDPOINT_SIZE,
 246         .bDescriptorType =      USB_DT_ENDPOINT,
 247
 248         .bEndpointAddress =     USB_DIR_IN,
 249         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 250         .wMaxPacketSize =       cpu_to_le16(512),
 251 };
 252
 253 static struct usb_endpoint_descriptor hs_ecm_out_desc = {
 254         .bLength =              USB_DT_ENDPOINT_SIZE,
 255         .bDescriptorType =      USB_DT_ENDPOINT,
 256
 257         .bEndpointAddress =     USB_DIR_OUT,
 258         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 259         .wMaxPacketSize =       cpu_to_le16(512),
 260 };
 261
 262 static struct usb_descriptor_header *ecm_hs_function[] = {
 263         /* CDC ECM control descriptors */
 264         (struct usb_descriptor_header *) &ecm_iad_descriptor,
 265         (struct usb_descriptor_header *) &ecm_control_intf,
 266         (struct usb_descriptor_header *) &ecm_header_desc,
 267         (struct usb_descriptor_header *) &ecm_union_desc,
 268         (struct usb_descriptor_header *) &ecm_desc,
 269
 270         /* NOTE: status endpoint might need to be removed */
 271         (struct usb_descriptor_header *) &hs_ecm_notify_desc,
 272
 273         /* data interface, altsettings 0 and 1 */
 274         (struct usb_descriptor_header *) &ecm_data_nop_intf,
 275         (struct usb_descriptor_header *) &ecm_data_intf,
 276         (struct usb_descriptor_header *) &hs_ecm_in_desc,
 277         (struct usb_descriptor_header *) &hs_ecm_out_desc,
 278         NULL,
 279 };
 280
 281 /* super speed support: */
 282
 283 static struct usb_endpoint_descriptor ss_ecm_notify_desc = {
 284         .bLength =              USB_DT_ENDPOINT_SIZE,
 285         .bDescriptorType =      USB_DT_ENDPOINT,
 286
 287         .bEndpointAddress =     USB_DIR_IN,
 288         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 289         .wMaxPacketSize =       cpu_to_le16(ECM_STATUS_BYTECOUNT),
 290         .bInterval =            USB_MS_TO_HS_INTERVAL(ECM_STATUS_INTERVAL_MS),
 291 };
 292
 293 static struct usb_ss_ep_comp_descriptor ss_ecm_intr_comp_desc = {
 294         .bLength =              sizeof ss_ecm_intr_comp_desc,
 295         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 296
 297         /* the following 3 values can be tweaked if necessary */
 298         /* .bMaxBurst =         0, */
 299         /* .bmAttributes =      0, */
 300         .wBytesPerInterval =    cpu_to_le16(ECM_STATUS_BYTECOUNT),
 301 };
 302
 303 static struct usb_endpoint_descriptor ss_ecm_in_desc = {
 304         .bLength =              USB_DT_ENDPOINT_SIZE,
 305         .bDescriptorType =      USB_DT_ENDPOINT,
 306
 307         .bEndpointAddress =     USB_DIR_IN,
 308         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 309         .wMaxPacketSize =       cpu_to_le16(1024),
 310 };
 311
 312 static struct usb_endpoint_descriptor ss_ecm_out_desc = {
 313         .bLength =              USB_DT_ENDPOINT_SIZE,
 314         .bDescriptorType =      USB_DT_ENDPOINT,
 315
 316         .bEndpointAddress =     USB_DIR_OUT,
 317         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 318         .wMaxPacketSize =       cpu_to_le16(1024),
 319 };
 320
 321 static struct usb_ss_ep_comp_descriptor ss_ecm_bulk_comp_desc = {
 322         .bLength =              sizeof ss_ecm_bulk_comp_desc,
 323         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 324
 325         /* the following 2 values can be tweaked if necessary */
 326         /* .bMaxBurst =         0, */
 327         /* .bmAttributes =      0, */
 328 };
 329
 330 static struct usb_descriptor_header *ecm_ss_function[] = {
 331         /* CDC ECM control descriptors */
 332         (struct usb_descriptor_header *) &ecm_iad_descriptor,
 333         (struct usb_descriptor_header *) &ecm_control_intf,
 334         (struct usb_descriptor_header *) &ecm_header_desc,
 335         (struct usb_descriptor_header *) &ecm_union_desc,
 336         (struct usb_descriptor_header *) &ecm_desc,
 337
 338         /* NOTE: status endpoint might need to be removed */
 339         (struct usb_descriptor_header *) &ss_ecm_notify_desc,
 340         (struct usb_descriptor_header *) &ss_ecm_intr_comp_desc,
 341
 342         /* data interface, altsettings 0 and 1 */
 343         (struct usb_descriptor_header *) &ecm_data_nop_intf,
 344         (struct usb_descriptor_header *) &ecm_data_intf,
 345         (struct usb_descriptor_header *) &ss_ecm_in_desc,
 346         (struct usb_descriptor_header *) &ss_ecm_bulk_comp_desc,
 347         (struct usb_descriptor_header *) &ss_ecm_out_desc,
 348         (struct usb_descriptor_header *) &ss_ecm_bulk_comp_desc,
 349         NULL,
 350 };
 351
 352 /* string descriptors: */
 353
 354 static struct usb_string ecm_string_defs[] = {
 355         [0].s = "CDC Ethernet Control Model (ECM)",
 356         [1].s = "",
 357         [2].s = "CDC Ethernet Data",
 358         [3].s = "CDC ECM",
 359         {  } /* end of list */
 360 };
 361
 362 static struct usb_gadget_strings ecm_string_table = {
 363         .language =             0x0409, /* en-us */
 364         .strings =              ecm_string_defs,
 365 };
 366
 367 static struct usb_gadget_strings *ecm_strings[] = {
 368         &ecm_string_table,
 369         NULL,
 370 };
 371
 372 /*-------------------------------------------------------------------------*/
 373
 374 static void ecm_do_notify(struct f_ecm *ecm)
 375 {
 376         struct usb_request              *req = ecm->notify_req;
 377         struct usb_cdc_notification     *event;
 378         struct usb_composite_dev        *cdev = ecm->port.func.config->cdev;
 379         __le32                          *data;
 380         int                             status;
 381
 382         /* notification already in flight? */
 383         if (!req)
 384                 return;
 385
 386         event = req->buf;
 387         switch (ecm->notify_state) {
 388         case ECM_NOTIFY_NONE:
 389                 return;
 390
 391         case ECM_NOTIFY_CONNECT:
 392                 event->bNotificationType = USB_CDC_NOTIFY_NETWORK_CONNECTION;
 393                 if (ecm->is_open)
 394                         event->wValue = cpu_to_le16(1);
 395                 else
 396                         event->wValue = cpu_to_le16(0);
 397                 event->wLength = 0;
 398                 req->length = sizeof *event;
 399
 400                 DBG(cdev, "notify connect %s\n",
 401                                 ecm->is_open ? "true" : "false");
 402                 ecm->notify_state = ECM_NOTIFY_SPEED;
 403                 break;
 404
 405         case ECM_NOTIFY_SPEED:
 406                 event->bNotificationType = USB_CDC_NOTIFY_SPEED_CHANGE;
 407                 event->wValue = cpu_to_le16(0);
 408                 event->wLength = cpu_to_le16(8);
 409                 req->length = ECM_STATUS_BYTECOUNT;
 410
 411                 /* SPEED_CHANGE data is up/down speeds in bits/sec */
 412                 data = req->buf + sizeof *event;
 413                 data[0] = cpu_to_le32(ecm_bitrate(cdev->gadget));
 414                 data[1] = data[0];
 415
 416                 DBG(cdev, "notify speed %d\n", ecm_bitrate(cdev->gadget));
 417                 ecm->notify_state = ECM_NOTIFY_NONE;
 418                 break;
 419         }
 420         event->bmRequestType = 0xA1;
 421         event->wIndex = cpu_to_le16(ecm->ctrl_id);
 422
 423         ecm->notify_req = NULL;
 424         status = usb_ep_queue(ecm->notify, req, GFP_ATOMIC);
 425         if (status < 0) {
 426                 ecm->notify_req = req;
 427                 DBG(cdev, "notify --> %d\n", status);
 428         }
 429 }
 430
 431 static void ecm_notify(struct f_ecm *ecm)
 432 {
 433         /* NOTE on most versions of Linux, host side cdc-ethernet
 434          * won't listen for notifications until its netdevice opens.
 435          * The first notification then sits in the FIFO for a long
 436          * time, and the second one is queued.
 437          */
 438         ecm->notify_state = ECM_NOTIFY_CONNECT;
 439         ecm_do_notify(ecm);
 440 }
 441
 442 static void ecm_notify_complete(struct usb_ep *ep, struct usb_request *req)
 443 {
 444         struct f_ecm                    *ecm = req->context;
 445         struct usb_composite_dev        *cdev = ecm->port.func.config->cdev;
 446         struct usb_cdc_notification     *event = req->buf;
 447
 448         switch (req->status) {
 449         case 0:
 450                 /* no fault */
 451                 break;
 452         case -ECONNRESET:
 453         case -ESHUTDOWN:
 454                 ecm->notify_state = ECM_NOTIFY_NONE;
 455                 break;
 456         default:
 457                 DBG(cdev, "event %02x --> %d\n",
 458                         event->bNotificationType, req->status);
 459                 break;
 460         }
 461         ecm->notify_req = req;
 462         ecm_do_notify(ecm);
 463 }
 464
 465 static int ecm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 466 {
 467         struct f_ecm            *ecm = func_to_ecm(f);
 468         struct usb_composite_dev *cdev = f->config->cdev;
 469         struct usb_request      *req = cdev->req;
 470         int                     value = -EOPNOTSUPP;
 471         u16                     w_index = le16_to_cpu(ctrl->wIndex);
 472         u16                     w_value = le16_to_cpu(ctrl->wValue);
 473         u16                     w_length = le16_to_cpu(ctrl->wLength);
 474
 475         /* composite driver infrastructure handles everything except
 476          * CDC class messages; interface activation uses set_alt().
 477          */
 478         switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
 479         case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 480                         | USB_CDC_SET_ETHERNET_PACKET_FILTER:
 481                 /* see 6.2.30: no data, wIndex = interface,
 482                  * wValue = packet filter bitmap
 483                  */
 484                 if (w_length != 0 || w_index != ecm->ctrl_id)
 485                         goto invalid;
 486                 DBG(cdev, "packet filter %02x\n", w_value);
 487                 /* REVISIT locking of cdc_filter.  This assumes the UDC
 488                  * driver won't have a concurrent packet TX irq running on
 489                  * another CPU; or that if it does, this write is atomic...
 490                  */
 491                 ecm->port.cdc_filter = w_value;
 492                 value = 0;
 493                 break;
 494
 495         /* and optionally:
 496          * case USB_CDC_SEND_ENCAPSULATED_COMMAND:
 497          * case USB_CDC_GET_ENCAPSULATED_RESPONSE:
 498          * case USB_CDC_SET_ETHERNET_MULTICAST_FILTERS:
 499          * case USB_CDC_SET_ETHERNET_PM_PATTERN_FILTER:
 500          * case USB_CDC_GET_ETHERNET_PM_PATTERN_FILTER:
 501          * case USB_CDC_GET_ETHERNET_STATISTIC:
 502          */
 503
 504         default:
 505 invalid:
 506                 DBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
 507                         ctrl->bRequestType, ctrl->bRequest,
 508                         w_value, w_index, w_length);
 509         }
 510
 511         /* respond with data transfer or status phase? */
 512         if (value >= 0) {
 513                 DBG(cdev, "ecm req%02x.%02x v%04x i%04x l%d\n",
 514                         ctrl->bRequestType, ctrl->bRequest,
 515                         w_value, w_index, w_length);
 516                 req->zero = 0;
 517                 req->length = value;
 518                 value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
 519                 if (value < 0)
 520                         ERROR(cdev, "ecm req %02x.%02x response err %d\n",
 521                                         ctrl->bRequestType, ctrl->bRequest,
 522                                         value);
 523         }
 524
 525         /* device either stalls (value < 0) or reports success */
 526         return value;
 527 }
 528
 529
 530 static int ecm_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 531 {
 532         struct f_ecm            *ecm = func_to_ecm(f);
 533         struct usb_composite_dev *cdev = f->config->cdev;
 534
 535         /* Control interface has only altsetting 0 */
 536         if (intf == ecm->ctrl_id) {
 537                 if (alt != 0)
 538                         goto fail;
 539
 540                 VDBG(cdev, "reset ecm control %d\n", intf);
 541                 usb_ep_disable(ecm->notify);
 542                 if (!(ecm->notify->desc)) {
 543                         VDBG(cdev, "init ecm ctrl %d\n", intf);
 544                         if (config_ep_by_speed(cdev->gadget, f, ecm->notify))
 545                                 goto fail;
 546                 }
 547                 usb_ep_enable(ecm->notify);
 548
 549         /* Data interface has two altsettings, 0 and 1 */
 550         } else if (intf == ecm->data_id) {
 551                 if (alt > 1)
 552                         goto fail;
 553
 554                 if (ecm->port.in_ep->enabled) {
 555                         DBG(cdev, "reset ecm\n");
 556                         gether_disconnect(&ecm->port);
 557                 }
 558
 559                 if (!ecm->port.in_ep->desc ||
 560                     !ecm->port.out_ep->desc) {
 561                         DBG(cdev, "init ecm\n");
 562                         if (config_ep_by_speed(cdev->gadget, f,
 563                                                ecm->port.in_ep) ||
 564                             config_ep_by_speed(cdev->gadget, f,
 565                                                ecm->port.out_ep)) {
 566                                 ecm->port.in_ep->desc = NULL;
 567                                 ecm->port.out_ep->desc = NULL;
 568                                 goto fail;
 569                         }
 570                 }
 571
 572                 /* CDC Ethernet only sends data in non-default altsettings.
 573                  * Changing altsettings resets filters, statistics, etc.
 574                  */
 575                 if (alt == 1) {
 576                         struct net_device       *net;
 577
 578                         /* Enable zlps by default for ECM conformance;
 579                          * override for musb_hdrc (avoids txdma ovhead).
 580                          */
 581                         ecm->port.is_zlp_ok =
 582                                 gadget_is_zlp_supported(cdev->gadget);
 583                         ecm->port.cdc_filter = DEFAULT_FILTER;
 584                         DBG(cdev, "activate ecm\n");
 585                         net = gether_connect(&ecm->port);
 586                         if (IS_ERR(net))
 587                                 return PTR_ERR(net);
 588                 }
 589
 590                 /* NOTE this can be a minor disagreement with the ECM spec,
 591                  * which says speed notifications will "always" follow
 592                  * connection notifications.  But we allow one connect to
 593                  * follow another (if the first is in flight), and instead
 594                  * just guarantee that a speed notification is always sent.
 595                  */
 596                 ecm_notify(ecm);
 597         } else
 598                 goto fail;
 599
 600         return 0;
 601 fail:
 602         return -EINVAL;
 603 }
 604
 605 /* Because the data interface supports multiple altsettings,
 606  * this ECM function *MUST* implement a get_alt() method.
 607  */
 608 static int ecm_get_alt(struct usb_function *f, unsigned intf)
 609 {
 610         struct f_ecm            *ecm = func_to_ecm(f);
 611
 612         if (intf == ecm->ctrl_id)
 613                 return 0;
 614         return ecm->port.in_ep->enabled ? 1 : 0;
 615 }
 616
 617 static void ecm_disable(struct usb_function *f)
 618 {
 619         struct f_ecm            *ecm = func_to_ecm(f);
 620         struct usb_composite_dev *cdev = f->config->cdev;
 621
 622         DBG(cdev, "ecm deactivated\n");
 623
 624         if (ecm->port.in_ep->enabled)
 625                 gether_disconnect(&ecm->port);
 626
 627         usb_ep_disable(ecm->notify);
 628         ecm->notify->desc = NULL;
 629 }
 630
 631 /*-------------------------------------------------------------------------*/
 632
 633 /*
 634  * Callbacks let us notify the host about connect/disconnect when the
 635  * net device is opened or closed.
 636  *
 637  * For testing, note that link states on this side include both opened
 638  * and closed variants of:
 639  *
 640  *   - disconnected/unconfigured
 641  *   - configured but inactive (data alt 0)
 642  *   - configured and active (data alt 1)
 643  *
 644  * Each needs to be tested with unplug, rmmod, SET_CONFIGURATION, and
 645  * SET_INTERFACE (altsetting).  Remember also that "configured" doesn't
 646  * imply the host is actually polling the notification endpoint, and
 647  * likewise that "active" doesn't imply it's actually using the data
 648  * endpoints for traffic.
 649  */
 650
 651 static void ecm_open(struct gether *geth)
 652 {
 653         struct f_ecm            *ecm = func_to_ecm(&geth->func);
 654
 655         DBG(ecm->port.func.config->cdev, "%s\n", __func__);
 656
 657         ecm->is_open = true;
 658         ecm_notify(ecm);
 659 }
 660
 661 static void ecm_close(struct gether *geth)
 662 {
 663         struct f_ecm            *ecm = func_to_ecm(&geth->func);
 664
 665         DBG(ecm->port.func.config->cdev, "%s\n", __func__);
 666
 667         ecm->is_open = false;
 668         ecm_notify(ecm);
 669 }
 670
 671 /*-------------------------------------------------------------------------*/
 672
 673 /* ethernet function driver setup/binding */
 674
 675 static int
 676 ecm_bind(struct usb_configuration *c, struct usb_function *f)
 677 {
 678         struct usb_composite_dev *cdev = c->cdev;
 679         struct f_ecm            *ecm = func_to_ecm(f);
 680         struct usb_string       *us;
 681         int                     status;
 682         struct usb_ep           *ep;
 683
 684         struct f_ecm_opts       *ecm_opts;
 685
 686         if (!can_support_ecm(cdev->gadget))
 687                 return -EINVAL;
 688
 689         ecm_opts = container_of(f->fi, struct f_ecm_opts, func_inst);
 690
 691         /*
 692          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
 693          * configurations are bound in sequence with list_for_each_entry,
 694          * in each configuration its functions are bound in sequence
 695          * with list_for_each_entry, so we assume no race condition
 696          * with regard to ecm_opts->bound access
 697          */
 698         if (!ecm_opts->bound) {
 699                 mutex_lock(&ecm_opts->lock);
 700                 gether_set_gadget(ecm_opts->net, cdev->gadget);
 701                 status = gether_register_netdev(ecm_opts->net);
 702                 mutex_unlock(&ecm_opts->lock);
 703                 if (status)
 704                         return status;
 705                 ecm_opts->bound = true;
 706         }
 707
 708         ecm_string_defs[1].s = ecm->ethaddr;
 709
 710         us = usb_gstrings_attach(cdev, ecm_strings,
 711                                  ARRAY_SIZE(ecm_string_defs));
 712         if (IS_ERR(us))
 713                 return PTR_ERR(us);
 714         ecm_control_intf.iInterface = us[0].id;
 715         ecm_data_intf.iInterface = us[2].id;
 716         ecm_desc.iMACAddress = us[1].id;
 717         ecm_iad_descriptor.iFunction = us[3].id;
 718
 719         /* allocate instance-specific interface IDs */
 720         status = usb_interface_id(c, f);
 721         if (status < 0)
 722                 goto fail;
 723         ecm->ctrl_id = status;
 724         ecm_iad_descriptor.bFirstInterface = status;
 725
 726         ecm_control_intf.bInterfaceNumber = status;
 727         ecm_union_desc.bMasterInterface0 = status;
 728
 729         status = usb_interface_id(c, f);
 730         if (status < 0)
 731                 goto fail;
 732         ecm->data_id = status;
 733
 734         ecm_data_nop_intf.bInterfaceNumber = status;
 735         ecm_data_intf.bInterfaceNumber = status;
 736         ecm_union_desc.bSlaveInterface0 = status;
 737
 738         status = -ENODEV;
 739
 740         /* allocate instance-specific endpoints */
 741         ep = usb_ep_autoconfig(cdev->gadget, &fs_ecm_in_desc);
 742         if (!ep)
 743                 goto fail;
 744         ecm->port.in_ep = ep;
 745
 746         ep = usb_ep_autoconfig(cdev->gadget, &fs_ecm_out_desc);
 747         if (!ep)
 748                 goto fail;
 749         ecm->port.out_ep = ep;
 750
 751         /* NOTE:  a status/notification endpoint is *OPTIONAL* but we
 752          * don't treat it that way.  It's simpler, and some newer CDC
 753          * profiles (wireless handsets) no longer treat it as optional.
 754          */
 755         ep = usb_ep_autoconfig(cdev->gadget, &fs_ecm_notify_desc);
 756         if (!ep)
 757                 goto fail;
 758         ecm->notify = ep;
 759
 760         status = -ENOMEM;
 761
 762         /* allocate notification request and buffer */
 763         ecm->notify_req = usb_ep_alloc_request(ep, GFP_KERNEL);
 764         if (!ecm->notify_req)
 765                 goto fail;
 766         ecm->notify_req->buf = kmalloc(ECM_STATUS_BYTECOUNT, GFP_KERNEL);
 767         if (!ecm->notify_req->buf)
 768                 goto fail;
 769         ecm->notify_req->context = ecm;
 770         ecm->notify_req->complete = ecm_notify_complete;
 771
 772         /* support all relevant hardware speeds... we expect that when
 773          * hardware is dual speed, all bulk-capable endpoints work at
 774          * both speeds
 775          */
 776         hs_ecm_in_desc.bEndpointAddress = fs_ecm_in_desc.bEndpointAddress;
 777         hs_ecm_out_desc.bEndpointAddress = fs_ecm_out_desc.bEndpointAddress;
 778         hs_ecm_notify_desc.bEndpointAddress =
 779                 fs_ecm_notify_desc.bEndpointAddress;
 780
 781         ss_ecm_in_desc.bEndpointAddress = fs_ecm_in_desc.bEndpointAddress;
 782         ss_ecm_out_desc.bEndpointAddress = fs_ecm_out_desc.bEndpointAddress;
 783         ss_ecm_notify_desc.bEndpointAddress =
 784                 fs_ecm_notify_desc.bEndpointAddress;
 785
 786         status = usb_assign_descriptors(f, ecm_fs_function, ecm_hs_function,
 787                         ecm_ss_function, NULL);
 788         if (status)
 789                 goto fail;
 790
 791         /* NOTE:  all that is done without knowing or caring about
 792          * the network link ... which is unavailable to this code
 793          * until we're activated via set_alt().
 794          */
 795
 796         ecm->port.open = ecm_open;
 797         ecm->port.close = ecm_close;
 798
 799         DBG(cdev, "CDC Ethernet: %s speed IN/%s OUT/%s NOTIFY/%s\n",
 800                         gadget_is_superspeed(c->cdev->gadget) ? "super" :
 801                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 802                         ecm->port.in_ep->name, ecm->port.out_ep->name,
 803                         ecm->notify->name);
 804         return 0;
 805
 806 fail:
 807         if (ecm->notify_req) {
 808                 kfree(ecm->notify_req->buf);
 809                 usb_ep_free_request(ecm->notify, ecm->notify_req);
 810         }
 811
 812         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 813
 814         return status;
 815 }
 816
 817 static inline struct f_ecm_opts *to_f_ecm_opts(struct config_item *item)
 818 {
 819         return container_of(to_config_group(item), struct f_ecm_opts,
 820                             func_inst.group);
 821 }
 822
 823 /* f_ecm_item_ops */
 824 USB_ETHERNET_CONFIGFS_ITEM(ecm);
 825
 826 /* f_ecm_opts_dev_addr */
 827 USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(ecm);
 828
 829 /* f_ecm_opts_host_addr */
 830 USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(ecm);
 831
 832 /* f_ecm_opts_qmult */
 833 USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(ecm);
 834
 835 /* f_ecm_opts_ifname */
 836 USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(ecm);
 837
 838 static struct configfs_attribute *ecm_attrs[] = {
 839         &ecm_opts_attr_dev_addr,
 840         &ecm_opts_attr_host_addr,
 841         &ecm_opts_attr_qmult,
 842         &ecm_opts_attr_ifname,
 843         NULL,
 844 };
 845
 846 static const struct config_item_type ecm_func_type = {
 847         .ct_item_ops    = &ecm_item_ops,
 848         .ct_attrs       = ecm_attrs,
 849         .ct_owner       = THIS_MODULE,
 850 };
 851
 852 static void ecm_free_inst(struct usb_function_instance *f)
 853 {
 854         struct f_ecm_opts *opts;
 855
 856         opts = container_of(f, struct f_ecm_opts, func_inst);
 857         if (opts->bound)
 858                 gether_cleanup(netdev_priv(opts->net));
 859         else
 860                 free_netdev(opts->net);
 861         kfree(opts);
 862 }
 863
 864 static struct usb_function_instance *ecm_alloc_inst(void)
 865 {
 866         struct f_ecm_opts *opts;
 867
 868         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 869         if (!opts)
 870                 return ERR_PTR(-ENOMEM);
 871         mutex_init(&opts->lock);
 872         opts->func_inst.free_func_inst = ecm_free_inst;
 873         opts->net = gether_setup_default();
 874         if (IS_ERR(opts->net)) {
 875                 struct net_device *net = opts->net;
 876                 kfree(opts);
 877                 return ERR_CAST(net);
 878         }
 879
 880         config_group_init_type_name(&opts->func_inst.group, "", &ecm_func_type);
 881
 882         return &opts->func_inst;
 883 }
 884
 885 static void ecm_free(struct usb_function *f)
 886 {
 887         struct f_ecm *ecm;
 888         struct f_ecm_opts *opts;
 889
 890         ecm = func_to_ecm(f);
 891         opts = container_of(f->fi, struct f_ecm_opts, func_inst);
 892         kfree(ecm);
 893         mutex_lock(&opts->lock);
 894         opts->refcnt--;
 895         mutex_unlock(&opts->lock);
 896 }
 897
 898 static void ecm_unbind(struct usb_configuration *c, struct usb_function *f)
 899 {
 900         struct f_ecm            *ecm = func_to_ecm(f);
 901
 902         DBG(c->cdev, "ecm unbind\n");
 903
 904         usb_free_all_descriptors(f);
 905
 906         kfree(ecm->notify_req->buf);
 907         usb_ep_free_request(ecm->notify, ecm->notify_req);
 908 }
 909
 910 static struct usb_function *ecm_alloc(struct usb_function_instance *fi)
 911 {
 912         struct f_ecm    *ecm;
 913         struct f_ecm_opts *opts;
 914         int status;
 915
 916         /* allocate and initialize one new instance */
 917         ecm = kzalloc(sizeof(*ecm), GFP_KERNEL);
 918         if (!ecm)
 919                 return ERR_PTR(-ENOMEM);
 920
 921         opts = container_of(fi, struct f_ecm_opts, func_inst);
 922         mutex_lock(&opts->lock);
 923         opts->refcnt++;
 924
 925         /* export host's Ethernet address in CDC format */
 926         status = gether_get_host_addr_cdc(opts->net, ecm->ethaddr,
 927                                           sizeof(ecm->ethaddr));
 928         if (status < 12) {
 929                 kfree(ecm);
 930                 mutex_unlock(&opts->lock);
 931                 return ERR_PTR(-EINVAL);
 932         }
 933
 934         ecm->port.ioport = netdev_priv(opts->net);
 935         mutex_unlock(&opts->lock);
 936         ecm->port.cdc_filter = DEFAULT_FILTER;
 937
 938         ecm->port.func.name = "cdc_ethernet";
 939         /* descriptors are per-instance copies */
 940         ecm->port.func.bind = ecm_bind;
 941         ecm->port.func.unbind = ecm_unbind;
 942         ecm->port.func.set_alt = ecm_set_alt;
 943         ecm->port.func.get_alt = ecm_get_alt;
 944         ecm->port.func.setup = ecm_setup;
 945         ecm->port.func.disable = ecm_disable;
 946         ecm->port.func.free_func = ecm_free;
 947
 948         return &ecm->port.func;
 949 }
 950
 951 DECLARE_USB_FUNCTION_INIT(ecm, ecm_alloc_inst, ecm_alloc);
 952 MODULE_LICENSE("GPL");
 953 MODULE_AUTHOR("David Brownell");