linux/drivers/usb/gadget/f_acm.c
<<
>>
Prefs
   1/*
   2 * f_acm.c -- USB CDC serial (ACM) function driver
   3 *
   4 * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
   5 * Copyright (C) 2008 by David Brownell
   6 * Copyright (C) 2008 by Nokia Corporation
   7 * Copyright (C) 2009 by Samsung Electronics
   8 * Author: Michal Nazarewicz (m.nazarewicz@samsung.com)
   9 *
  10 * This software is distributed under the terms of the GNU General
  11 * Public License ("GPL") as published by the Free Software Foundation,
  12 * either version 2 of that License or (at your option) any later version.
  13 */
  14
  15/* #define VERBOSE_DEBUG */
  16
  17#include <linux/slab.h>
  18#include <linux/kernel.h>
  19#include <linux/device.h>
  20
  21#include "u_serial.h"
  22#include "gadget_chips.h"
  23
  24
  25/*
  26 * This CDC ACM function support just wraps control functions and
  27 * notifications around the generic serial-over-usb code.
  28 *
  29 * Because CDC ACM is standardized by the USB-IF, many host operating
  30 * systems have drivers for it.  Accordingly, ACM is the preferred
  31 * interop solution for serial-port type connections.  The control
  32 * models are often not necessary, and in any case don't do much in
  33 * this bare-bones implementation.
  34 *
  35 * Note that even MS-Windows has some support for ACM.  However, that
  36 * support is somewhat broken because when you use ACM in a composite
  37 * device, having multiple interfaces confuses the poor OS.  It doesn't
  38 * seem to understand CDC Union descriptors.  The new "association"
  39 * descriptors (roughly equivalent to CDC Unions) may sometimes help.
  40 */
  41
  42struct f_acm {
  43        struct gserial                  port;
  44        u8                              ctrl_id, data_id;
  45        u8                              port_num;
  46
  47        u8                              pending;
  48
  49        /* lock is mostly for pending and notify_req ... they get accessed
  50         * by callbacks both from tty (open/close/break) under its spinlock,
  51         * and notify_req.complete() which can't use that lock.
  52         */
  53        spinlock_t                      lock;
  54
  55        struct usb_ep                   *notify;
  56        struct usb_request              *notify_req;
  57
  58        struct usb_cdc_line_coding      port_line_coding;       /* 8-N-1 etc */
  59
  60        /* SetControlLineState request -- CDC 1.1 section 6.2.14 (INPUT) */
  61        u16                             port_handshake_bits;
  62#define ACM_CTRL_RTS    (1 << 1)        /* unused with full duplex */
  63#define ACM_CTRL_DTR    (1 << 0)        /* host is ready for data r/w */
  64
  65        /* SerialState notification -- CDC 1.1 section 6.3.5 (OUTPUT) */
  66        u16                             serial_state;
  67#define ACM_CTRL_OVERRUN        (1 << 6)
  68#define ACM_CTRL_PARITY         (1 << 5)
  69#define ACM_CTRL_FRAMING        (1 << 4)
  70#define ACM_CTRL_RI             (1 << 3)
  71#define ACM_CTRL_BRK            (1 << 2)
  72#define ACM_CTRL_DSR            (1 << 1)
  73#define ACM_CTRL_DCD            (1 << 0)
  74};
  75
  76static inline struct f_acm *func_to_acm(struct usb_function *f)
  77{
  78        return container_of(f, struct f_acm, port.func);
  79}
  80
  81static inline struct f_acm *port_to_acm(struct gserial *p)
  82{
  83        return container_of(p, struct f_acm, port);
  84}
  85
  86/*-------------------------------------------------------------------------*/
  87
  88/* notification endpoint uses smallish and infrequent fixed-size messages */
  89
  90#define GS_LOG2_NOTIFY_INTERVAL         5       /* 1 << 5 == 32 msec */
  91#define GS_NOTIFY_MAXPACKET             10      /* notification + 2 bytes */
  92
  93/* interface and class descriptors: */
  94
  95static struct usb_interface_assoc_descriptor
  96acm_iad_descriptor = {
  97        .bLength =              sizeof acm_iad_descriptor,
  98        .bDescriptorType =      USB_DT_INTERFACE_ASSOCIATION,
  99
 100        /* .bFirstInterface =   DYNAMIC, */
 101        .bInterfaceCount =      2,      // control + data
 102        .bFunctionClass =       USB_CLASS_COMM,
 103        .bFunctionSubClass =    USB_CDC_SUBCLASS_ACM,
 104        .bFunctionProtocol =    USB_CDC_ACM_PROTO_AT_V25TER,
 105        /* .iFunction =         DYNAMIC */
 106};
 107
 108
 109static struct usb_interface_descriptor acm_control_interface_desc = {
 110        .bLength =              USB_DT_INTERFACE_SIZE,
 111        .bDescriptorType =      USB_DT_INTERFACE,
 112        /* .bInterfaceNumber = DYNAMIC */
 113        .bNumEndpoints =        1,
 114        .bInterfaceClass =      USB_CLASS_COMM,
 115        .bInterfaceSubClass =   USB_CDC_SUBCLASS_ACM,
 116        .bInterfaceProtocol =   USB_CDC_ACM_PROTO_AT_V25TER,
 117        /* .iInterface = DYNAMIC */
 118};
 119
 120static struct usb_interface_descriptor acm_data_interface_desc = {
 121        .bLength =              USB_DT_INTERFACE_SIZE,
 122        .bDescriptorType =      USB_DT_INTERFACE,
 123        /* .bInterfaceNumber = DYNAMIC */
 124        .bNumEndpoints =        2,
 125        .bInterfaceClass =      USB_CLASS_CDC_DATA,
 126        .bInterfaceSubClass =   0,
 127        .bInterfaceProtocol =   0,
 128        /* .iInterface = DYNAMIC */
 129};
 130
 131static struct usb_cdc_header_desc acm_header_desc = {
 132        .bLength =              sizeof(acm_header_desc),
 133        .bDescriptorType =      USB_DT_CS_INTERFACE,
 134        .bDescriptorSubType =   USB_CDC_HEADER_TYPE,
 135        .bcdCDC =               cpu_to_le16(0x0110),
 136};
 137
 138static struct usb_cdc_call_mgmt_descriptor
 139acm_call_mgmt_descriptor = {
 140        .bLength =              sizeof(acm_call_mgmt_descriptor),
 141        .bDescriptorType =      USB_DT_CS_INTERFACE,
 142        .bDescriptorSubType =   USB_CDC_CALL_MANAGEMENT_TYPE,
 143        .bmCapabilities =       0,
 144        /* .bDataInterface = DYNAMIC */
 145};
 146
 147static struct usb_cdc_acm_descriptor acm_descriptor = {
 148        .bLength =              sizeof(acm_descriptor),
 149        .bDescriptorType =      USB_DT_CS_INTERFACE,
 150        .bDescriptorSubType =   USB_CDC_ACM_TYPE,
 151        .bmCapabilities =       USB_CDC_CAP_LINE,
 152};
 153
 154static struct usb_cdc_union_desc acm_union_desc = {
 155        .bLength =              sizeof(acm_union_desc),
 156        .bDescriptorType =      USB_DT_CS_INTERFACE,
 157        .bDescriptorSubType =   USB_CDC_UNION_TYPE,
 158        /* .bMasterInterface0 = DYNAMIC */
 159        /* .bSlaveInterface0 =  DYNAMIC */
 160};
 161
 162/* full speed support: */
 163
 164static struct usb_endpoint_descriptor acm_fs_notify_desc = {
 165        .bLength =              USB_DT_ENDPOINT_SIZE,
 166        .bDescriptorType =      USB_DT_ENDPOINT,
 167        .bEndpointAddress =     USB_DIR_IN,
 168        .bmAttributes =         USB_ENDPOINT_XFER_INT,
 169        .wMaxPacketSize =       cpu_to_le16(GS_NOTIFY_MAXPACKET),
 170        .bInterval =            1 << GS_LOG2_NOTIFY_INTERVAL,
 171};
 172
 173static struct usb_endpoint_descriptor acm_fs_in_desc = {
 174        .bLength =              USB_DT_ENDPOINT_SIZE,
 175        .bDescriptorType =      USB_DT_ENDPOINT,
 176        .bEndpointAddress =     USB_DIR_IN,
 177        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 178};
 179
 180static struct usb_endpoint_descriptor acm_fs_out_desc = {
 181        .bLength =              USB_DT_ENDPOINT_SIZE,
 182        .bDescriptorType =      USB_DT_ENDPOINT,
 183        .bEndpointAddress =     USB_DIR_OUT,
 184        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 185};
 186
 187static struct usb_descriptor_header *acm_fs_function[] = {
 188        (struct usb_descriptor_header *) &acm_iad_descriptor,
 189        (struct usb_descriptor_header *) &acm_control_interface_desc,
 190        (struct usb_descriptor_header *) &acm_header_desc,
 191        (struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
 192        (struct usb_descriptor_header *) &acm_descriptor,
 193        (struct usb_descriptor_header *) &acm_union_desc,
 194        (struct usb_descriptor_header *) &acm_fs_notify_desc,
 195        (struct usb_descriptor_header *) &acm_data_interface_desc,
 196        (struct usb_descriptor_header *) &acm_fs_in_desc,
 197        (struct usb_descriptor_header *) &acm_fs_out_desc,
 198        NULL,
 199};
 200
 201/* high speed support: */
 202
 203static struct usb_endpoint_descriptor acm_hs_notify_desc = {
 204        .bLength =              USB_DT_ENDPOINT_SIZE,
 205        .bDescriptorType =      USB_DT_ENDPOINT,
 206        .bEndpointAddress =     USB_DIR_IN,
 207        .bmAttributes =         USB_ENDPOINT_XFER_INT,
 208        .wMaxPacketSize =       cpu_to_le16(GS_NOTIFY_MAXPACKET),
 209        .bInterval =            GS_LOG2_NOTIFY_INTERVAL+4,
 210};
 211
 212static struct usb_endpoint_descriptor acm_hs_in_desc = {
 213        .bLength =              USB_DT_ENDPOINT_SIZE,
 214        .bDescriptorType =      USB_DT_ENDPOINT,
 215        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 216        .wMaxPacketSize =       cpu_to_le16(512),
 217};
 218
 219static struct usb_endpoint_descriptor acm_hs_out_desc = {
 220        .bLength =              USB_DT_ENDPOINT_SIZE,
 221        .bDescriptorType =      USB_DT_ENDPOINT,
 222        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 223        .wMaxPacketSize =       cpu_to_le16(512),
 224};
 225
 226static struct usb_descriptor_header *acm_hs_function[] = {
 227        (struct usb_descriptor_header *) &acm_iad_descriptor,
 228        (struct usb_descriptor_header *) &acm_control_interface_desc,
 229        (struct usb_descriptor_header *) &acm_header_desc,
 230        (struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
 231        (struct usb_descriptor_header *) &acm_descriptor,
 232        (struct usb_descriptor_header *) &acm_union_desc,
 233        (struct usb_descriptor_header *) &acm_hs_notify_desc,
 234        (struct usb_descriptor_header *) &acm_data_interface_desc,
 235        (struct usb_descriptor_header *) &acm_hs_in_desc,
 236        (struct usb_descriptor_header *) &acm_hs_out_desc,
 237        NULL,
 238};
 239
 240/* string descriptors: */
 241
 242#define ACM_CTRL_IDX    0
 243#define ACM_DATA_IDX    1
 244#define ACM_IAD_IDX     2
 245
 246/* static strings, in UTF-8 */
 247static struct usb_string acm_string_defs[] = {
 248        [ACM_CTRL_IDX].s = "CDC Abstract Control Model (ACM)",
 249        [ACM_DATA_IDX].s = "CDC ACM Data",
 250        [ACM_IAD_IDX ].s = "CDC Serial",
 251        {  /* ZEROES END LIST */ },
 252};
 253
 254static struct usb_gadget_strings acm_string_table = {
 255        .language =             0x0409, /* en-us */
 256        .strings =              acm_string_defs,
 257};
 258
 259static struct usb_gadget_strings *acm_strings[] = {
 260        &acm_string_table,
 261        NULL,
 262};
 263
 264/*-------------------------------------------------------------------------*/
 265
 266/* ACM control ... data handling is delegated to tty library code.
 267 * The main task of this function is to activate and deactivate
 268 * that code based on device state; track parameters like line
 269 * speed, handshake state, and so on; and issue notifications.
 270 */
 271
 272static void acm_complete_set_line_coding(struct usb_ep *ep,
 273                struct usb_request *req)
 274{
 275        struct f_acm    *acm = ep->driver_data;
 276        struct usb_composite_dev *cdev = acm->port.func.config->cdev;
 277
 278        if (req->status != 0) {
 279                DBG(cdev, "acm ttyGS%d completion, err %d\n",
 280                                acm->port_num, req->status);
 281                return;
 282        }
 283
 284        /* normal completion */
 285        if (req->actual != sizeof(acm->port_line_coding)) {
 286                DBG(cdev, "acm ttyGS%d short resp, len %d\n",
 287                                acm->port_num, req->actual);
 288                usb_ep_set_halt(ep);
 289        } else {
 290                struct usb_cdc_line_coding      *value = req->buf;
 291
 292                /* REVISIT:  we currently just remember this data.
 293                 * If we change that, (a) validate it first, then
 294                 * (b) update whatever hardware needs updating,
 295                 * (c) worry about locking.  This is information on
 296                 * the order of 9600-8-N-1 ... most of which means
 297                 * nothing unless we control a real RS232 line.
 298                 */
 299                acm->port_line_coding = *value;
 300        }
 301}
 302
 303static int acm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 304{
 305        struct f_acm            *acm = func_to_acm(f);
 306        struct usb_composite_dev *cdev = f->config->cdev;
 307        struct usb_request      *req = cdev->req;
 308        int                     value = -EOPNOTSUPP;
 309        u16                     w_index = le16_to_cpu(ctrl->wIndex);
 310        u16                     w_value = le16_to_cpu(ctrl->wValue);
 311        u16                     w_length = le16_to_cpu(ctrl->wLength);
 312
 313        /* composite driver infrastructure handles everything except
 314         * CDC class messages; interface activation uses set_alt().
 315         *
 316         * Note CDC spec table 4 lists the ACM request profile.  It requires
 317         * encapsulated command support ... we don't handle any, and respond
 318         * to them by stalling.  Options include get/set/clear comm features
 319         * (not that useful) and SEND_BREAK.
 320         */
 321        switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
 322
 323        /* SET_LINE_CODING ... just read and save what the host sends */
 324        case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 325                        | USB_CDC_REQ_SET_LINE_CODING:
 326                if (w_length != sizeof(struct usb_cdc_line_coding)
 327                                || w_index != acm->ctrl_id)
 328                        goto invalid;
 329
 330                value = w_length;
 331                cdev->gadget->ep0->driver_data = acm;
 332                req->complete = acm_complete_set_line_coding;
 333                break;
 334
 335        /* GET_LINE_CODING ... return what host sent, or initial value */
 336        case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 337                        | USB_CDC_REQ_GET_LINE_CODING:
 338                if (w_index != acm->ctrl_id)
 339                        goto invalid;
 340
 341                value = min_t(unsigned, w_length,
 342                                sizeof(struct usb_cdc_line_coding));
 343                memcpy(req->buf, &acm->port_line_coding, value);
 344                break;
 345
 346        /* SET_CONTROL_LINE_STATE ... save what the host sent */
 347        case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 348                        | USB_CDC_REQ_SET_CONTROL_LINE_STATE:
 349                if (w_index != acm->ctrl_id)
 350                        goto invalid;
 351
 352                value = 0;
 353
 354                /* FIXME we should not allow data to flow until the
 355                 * host sets the ACM_CTRL_DTR bit; and when it clears
 356                 * that bit, we should return to that no-flow state.
 357                 */
 358                acm->port_handshake_bits = w_value;
 359                break;
 360
 361        default:
 362invalid:
 363                VDBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
 364                        ctrl->bRequestType, ctrl->bRequest,
 365                        w_value, w_index, w_length);
 366        }
 367
 368        /* respond with data transfer or status phase? */
 369        if (value >= 0) {
 370                DBG(cdev, "acm ttyGS%d req%02x.%02x v%04x i%04x l%d\n",
 371                        acm->port_num, ctrl->bRequestType, ctrl->bRequest,
 372                        w_value, w_index, w_length);
 373                req->zero = 0;
 374                req->length = value;
 375                value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
 376                if (value < 0)
 377                        ERROR(cdev, "acm response on ttyGS%d, err %d\n",
 378                                        acm->port_num, value);
 379        }
 380
 381        /* device either stalls (value < 0) or reports success */
 382        return value;
 383}
 384
 385static int acm_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 386{
 387        struct f_acm            *acm = func_to_acm(f);
 388        struct usb_composite_dev *cdev = f->config->cdev;
 389
 390        /* we know alt == 0, so this is an activation or a reset */
 391
 392        if (intf == acm->ctrl_id) {
 393                if (acm->notify->driver_data) {
 394                        VDBG(cdev, "reset acm control interface %d\n", intf);
 395                        usb_ep_disable(acm->notify);
 396                } else {
 397                        VDBG(cdev, "init acm ctrl interface %d\n", intf);
 398                        if (config_ep_by_speed(cdev->gadget, f, acm->notify))
 399                                return -EINVAL;
 400                }
 401                usb_ep_enable(acm->notify);
 402                acm->notify->driver_data = acm;
 403
 404        } else if (intf == acm->data_id) {
 405                if (acm->port.in->driver_data) {
 406                        DBG(cdev, "reset acm ttyGS%d\n", acm->port_num);
 407                        gserial_disconnect(&acm->port);
 408                }
 409                if (!acm->port.in->desc || !acm->port.out->desc) {
 410                        DBG(cdev, "activate acm ttyGS%d\n", acm->port_num);
 411                        if (config_ep_by_speed(cdev->gadget, f,
 412                                               acm->port.in) ||
 413                            config_ep_by_speed(cdev->gadget, f,
 414                                               acm->port.out)) {
 415                                acm->port.in->desc = NULL;
 416                                acm->port.out->desc = NULL;
 417                                return -EINVAL;
 418                        }
 419                }
 420                gserial_connect(&acm->port, acm->port_num);
 421
 422        } else
 423                return -EINVAL;
 424
 425        return 0;
 426}
 427
 428static void acm_disable(struct usb_function *f)
 429{
 430        struct f_acm    *acm = func_to_acm(f);
 431        struct usb_composite_dev *cdev = f->config->cdev;
 432
 433        DBG(cdev, "acm ttyGS%d deactivated\n", acm->port_num);
 434        gserial_disconnect(&acm->port);
 435        usb_ep_disable(acm->notify);
 436        acm->notify->driver_data = NULL;
 437}
 438
 439/*-------------------------------------------------------------------------*/
 440
 441/**
 442 * acm_cdc_notify - issue CDC notification to host
 443 * @acm: wraps host to be notified
 444 * @type: notification type
 445 * @value: Refer to cdc specs, wValue field.
 446 * @data: data to be sent
 447 * @length: size of data
 448 * Context: irqs blocked, acm->lock held, acm_notify_req non-null
 449 *
 450 * Returns zero on success or a negative errno.
 451 *
 452 * See section 6.3.5 of the CDC 1.1 specification for information
 453 * about the only notification we issue:  SerialState change.
 454 */
 455static int acm_cdc_notify(struct f_acm *acm, u8 type, u16 value,
 456                void *data, unsigned length)
 457{
 458        struct usb_ep                   *ep = acm->notify;
 459        struct usb_request              *req;
 460        struct usb_cdc_notification     *notify;
 461        const unsigned                  len = sizeof(*notify) + length;
 462        void                            *buf;
 463        int                             status;
 464
 465        req = acm->notify_req;
 466        acm->notify_req = NULL;
 467        acm->pending = false;
 468
 469        req->length = len;
 470        notify = req->buf;
 471        buf = notify + 1;
 472
 473        notify->bmRequestType = USB_DIR_IN | USB_TYPE_CLASS
 474                        | USB_RECIP_INTERFACE;
 475        notify->bNotificationType = type;
 476        notify->wValue = cpu_to_le16(value);
 477        notify->wIndex = cpu_to_le16(acm->ctrl_id);
 478        notify->wLength = cpu_to_le16(length);
 479        memcpy(buf, data, length);
 480
 481        /* ep_queue() can complete immediately if it fills the fifo... */
 482        spin_unlock(&acm->lock);
 483        status = usb_ep_queue(ep, req, GFP_ATOMIC);
 484        spin_lock(&acm->lock);
 485
 486        if (status < 0) {
 487                ERROR(acm->port.func.config->cdev,
 488                                "acm ttyGS%d can't notify serial state, %d\n",
 489                                acm->port_num, status);
 490                acm->notify_req = req;
 491        }
 492
 493        return status;
 494}
 495
 496static int acm_notify_serial_state(struct f_acm *acm)
 497{
 498        struct usb_composite_dev *cdev = acm->port.func.config->cdev;
 499        int                     status;
 500
 501        spin_lock(&acm->lock);
 502        if (acm->notify_req) {
 503                DBG(cdev, "acm ttyGS%d serial state %04x\n",
 504                                acm->port_num, acm->serial_state);
 505                status = acm_cdc_notify(acm, USB_CDC_NOTIFY_SERIAL_STATE,
 506                                0, &acm->serial_state, sizeof(acm->serial_state));
 507        } else {
 508                acm->pending = true;
 509                status = 0;
 510        }
 511        spin_unlock(&acm->lock);
 512        return status;
 513}
 514
 515static void acm_cdc_notify_complete(struct usb_ep *ep, struct usb_request *req)
 516{
 517        struct f_acm            *acm = req->context;
 518        u8                      doit = false;
 519
 520        /* on this call path we do NOT hold the port spinlock,
 521         * which is why ACM needs its own spinlock
 522         */
 523        spin_lock(&acm->lock);
 524        if (req->status != -ESHUTDOWN)
 525                doit = acm->pending;
 526        acm->notify_req = req;
 527        spin_unlock(&acm->lock);
 528
 529        if (doit)
 530                acm_notify_serial_state(acm);
 531}
 532
 533/* connect == the TTY link is open */
 534
 535static void acm_connect(struct gserial *port)
 536{
 537        struct f_acm            *acm = port_to_acm(port);
 538
 539        acm->serial_state |= ACM_CTRL_DSR | ACM_CTRL_DCD;
 540        acm_notify_serial_state(acm);
 541}
 542
 543static void acm_disconnect(struct gserial *port)
 544{
 545        struct f_acm            *acm = port_to_acm(port);
 546
 547        acm->serial_state &= ~(ACM_CTRL_DSR | ACM_CTRL_DCD);
 548        acm_notify_serial_state(acm);
 549}
 550
 551static int acm_send_break(struct gserial *port, int duration)
 552{
 553        struct f_acm            *acm = port_to_acm(port);
 554        u16                     state;
 555
 556        state = acm->serial_state;
 557        state &= ~ACM_CTRL_BRK;
 558        if (duration)
 559                state |= ACM_CTRL_BRK;
 560
 561        acm->serial_state = state;
 562        return acm_notify_serial_state(acm);
 563}
 564
 565/*-------------------------------------------------------------------------*/
 566
 567/* ACM function driver setup/binding */
 568static int
 569acm_bind(struct usb_configuration *c, struct usb_function *f)
 570{
 571        struct usb_composite_dev *cdev = c->cdev;
 572        struct f_acm            *acm = func_to_acm(f);
 573        int                     status;
 574        struct usb_ep           *ep;
 575
 576        /* allocate instance-specific interface IDs, and patch descriptors */
 577        status = usb_interface_id(c, f);
 578        if (status < 0)
 579                goto fail;
 580        acm->ctrl_id = status;
 581        acm_iad_descriptor.bFirstInterface = status;
 582
 583        acm_control_interface_desc.bInterfaceNumber = status;
 584        acm_union_desc .bMasterInterface0 = status;
 585
 586        status = usb_interface_id(c, f);
 587        if (status < 0)
 588                goto fail;
 589        acm->data_id = status;
 590
 591        acm_data_interface_desc.bInterfaceNumber = status;
 592        acm_union_desc.bSlaveInterface0 = status;
 593        acm_call_mgmt_descriptor.bDataInterface = status;
 594
 595        status = -ENODEV;
 596
 597        /* allocate instance-specific endpoints */
 598        ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_in_desc);
 599        if (!ep)
 600                goto fail;
 601        acm->port.in = ep;
 602        ep->driver_data = cdev; /* claim */
 603
 604        ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_out_desc);
 605        if (!ep)
 606                goto fail;
 607        acm->port.out = ep;
 608        ep->driver_data = cdev; /* claim */
 609
 610        ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_notify_desc);
 611        if (!ep)
 612                goto fail;
 613        acm->notify = ep;
 614        ep->driver_data = cdev; /* claim */
 615
 616        /* allocate notification */
 617        acm->notify_req = gs_alloc_req(ep,
 618                        sizeof(struct usb_cdc_notification) + 2,
 619                        GFP_KERNEL);
 620        if (!acm->notify_req)
 621                goto fail;
 622
 623        acm->notify_req->complete = acm_cdc_notify_complete;
 624        acm->notify_req->context = acm;
 625
 626        /* copy descriptors */
 627        f->descriptors = usb_copy_descriptors(acm_fs_function);
 628        if (!f->descriptors)
 629                goto fail;
 630
 631        /* support all relevant hardware speeds... we expect that when
 632         * hardware is dual speed, all bulk-capable endpoints work at
 633         * both speeds
 634         */
 635        if (gadget_is_dualspeed(c->cdev->gadget)) {
 636                acm_hs_in_desc.bEndpointAddress =
 637                                acm_fs_in_desc.bEndpointAddress;
 638                acm_hs_out_desc.bEndpointAddress =
 639                                acm_fs_out_desc.bEndpointAddress;
 640                acm_hs_notify_desc.bEndpointAddress =
 641                                acm_fs_notify_desc.bEndpointAddress;
 642
 643                /* copy descriptors */
 644                f->hs_descriptors = usb_copy_descriptors(acm_hs_function);
 645        }
 646
 647        DBG(cdev, "acm ttyGS%d: %s speed IN/%s OUT/%s NOTIFY/%s\n",
 648                        acm->port_num,
 649                        gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 650                        acm->port.in->name, acm->port.out->name,
 651                        acm->notify->name);
 652        return 0;
 653
 654fail:
 655        if (acm->notify_req)
 656                gs_free_req(acm->notify, acm->notify_req);
 657
 658        /* we might as well release our claims on endpoints */
 659        if (acm->notify)
 660                acm->notify->driver_data = NULL;
 661        if (acm->port.out)
 662                acm->port.out->driver_data = NULL;
 663        if (acm->port.in)
 664                acm->port.in->driver_data = NULL;
 665
 666        ERROR(cdev, "%s/%p: can't bind, err %d\n", f->name, f, status);
 667
 668        return status;
 669}
 670
 671static void
 672acm_unbind(struct usb_configuration *c, struct usb_function *f)
 673{
 674        struct f_acm            *acm = func_to_acm(f);
 675
 676        if (gadget_is_dualspeed(c->cdev->gadget))
 677                usb_free_descriptors(f->hs_descriptors);
 678        usb_free_descriptors(f->descriptors);
 679        gs_free_req(acm->notify, acm->notify_req);
 680        kfree(acm);
 681}
 682
 683/* Some controllers can't support CDC ACM ... */
 684static inline bool can_support_cdc(struct usb_configuration *c)
 685{
 686        /* everything else is *probably* fine ... */
 687        return true;
 688}
 689
 690/**
 691 * acm_bind_config - add a CDC ACM function to a configuration
 692 * @c: the configuration to support the CDC ACM instance
 693 * @port_num: /dev/ttyGS* port this interface will use
 694 * Context: single threaded during gadget setup
 695 *
 696 * Returns zero on success, else negative errno.
 697 *
 698 * Caller must have called @gserial_setup() with enough ports to
 699 * handle all the ones it binds.  Caller is also responsible
 700 * for calling @gserial_cleanup() before module unload.
 701 */
 702int acm_bind_config(struct usb_configuration *c, u8 port_num)
 703{
 704        struct f_acm    *acm;
 705        int             status;
 706
 707        if (!can_support_cdc(c))
 708                return -EINVAL;
 709
 710        /* REVISIT might want instance-specific strings to help
 711         * distinguish instances ...
 712         */
 713
 714        /* maybe allocate device-global string IDs, and patch descriptors */
 715        if (acm_string_defs[ACM_CTRL_IDX].id == 0) {
 716                status = usb_string_id(c->cdev);
 717                if (status < 0)
 718                        return status;
 719                acm_string_defs[ACM_CTRL_IDX].id = status;
 720
 721                acm_control_interface_desc.iInterface = status;
 722
 723                status = usb_string_id(c->cdev);
 724                if (status < 0)
 725                        return status;
 726                acm_string_defs[ACM_DATA_IDX].id = status;
 727
 728                acm_data_interface_desc.iInterface = status;
 729
 730                status = usb_string_id(c->cdev);
 731                if (status < 0)
 732                        return status;
 733                acm_string_defs[ACM_IAD_IDX].id = status;
 734
 735                acm_iad_descriptor.iFunction = status;
 736        }
 737
 738        /* allocate and initialize one new instance */
 739        acm = kzalloc(sizeof *acm, GFP_KERNEL);
 740        if (!acm)
 741                return -ENOMEM;
 742
 743        spin_lock_init(&acm->lock);
 744
 745        acm->port_num = port_num;
 746
 747        acm->port.connect = acm_connect;
 748        acm->port.disconnect = acm_disconnect;
 749        acm->port.send_break = acm_send_break;
 750
 751        acm->port.func.name = "acm";
 752        acm->port.func.strings = acm_strings;
 753        /* descriptors are per-instance copies */
 754        acm->port.func.bind = acm_bind;
 755        acm->port.func.unbind = acm_unbind;
 756        acm->port.func.set_alt = acm_set_alt;
 757        acm->port.func.setup = acm_setup;
 758        acm->port.func.disable = acm_disable;
 759
 760        status = usb_add_function(c, &acm->port.func);
 761        if (status)
 762                kfree(acm);
 763        return status;
 764}
 765