linux/drivers/usb/gadget/function/f_midi.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * f_midi.c -- USB MIDI class function driver
   4 *
   5 * Copyright (C) 2006 Thumtronics Pty Ltd.
   6 * Developed for Thumtronics by Grey Innovation
   7 * Ben Williamson <ben.williamson@greyinnovation.com>
   8 *
   9 * Rewritten for the composite framework
  10 *   Copyright (C) 2011 Daniel Mack <zonque@gmail.com>
  11 *
  12 * Based on drivers/usb/gadget/f_audio.c,
  13 *   Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
  14 *   Copyright (C) 2008 Analog Devices, Inc
  15 *
  16 * and drivers/usb/gadget/midi.c,
  17 *   Copyright (C) 2006 Thumtronics Pty Ltd.
  18 *   Ben Williamson <ben.williamson@greyinnovation.com>
  19 */
  20
  21#include <linux/kernel.h>
  22#include <linux/module.h>
  23#include <linux/slab.h>
  24#include <linux/device.h>
  25#include <linux/kfifo.h>
  26#include <linux/spinlock.h>
  27
  28#include <sound/core.h>
  29#include <sound/initval.h>
  30#include <sound/rawmidi.h>
  31
  32#include <linux/usb/ch9.h>
  33#include <linux/usb/gadget.h>
  34#include <linux/usb/audio.h>
  35#include <linux/usb/midi.h>
  36
  37#include "u_f.h"
  38#include "u_midi.h"
  39
  40MODULE_AUTHOR("Ben Williamson");
  41MODULE_LICENSE("GPL v2");
  42
  43static const char f_midi_shortname[] = "f_midi";
  44static const char f_midi_longname[] = "MIDI Gadget";
  45
  46/*
  47 * We can only handle 16 cables on one single endpoint, as cable numbers are
  48 * stored in 4-bit fields. And as the interface currently only holds one
  49 * single endpoint, this is the maximum number of ports we can allow.
  50 */
  51#define MAX_PORTS 16
  52
  53/* MIDI message states */
  54enum {
  55        STATE_INITIAL = 0,      /* pseudo state */
  56        STATE_1PARAM,
  57        STATE_2PARAM_1,
  58        STATE_2PARAM_2,
  59        STATE_SYSEX_0,
  60        STATE_SYSEX_1,
  61        STATE_SYSEX_2,
  62        STATE_REAL_TIME,
  63        STATE_FINISHED,         /* pseudo state */
  64};
  65
  66/*
  67 * This is a gadget, and the IN/OUT naming is from the host's perspective.
  68 * USB -> OUT endpoint -> rawmidi
  69 * USB <- IN endpoint  <- rawmidi
  70 */
  71struct gmidi_in_port {
  72        struct snd_rawmidi_substream *substream;
  73        int active;
  74        uint8_t cable;
  75        uint8_t state;
  76        uint8_t data[2];
  77};
  78
  79struct f_midi {
  80        struct usb_function     func;
  81        struct usb_gadget       *gadget;
  82        struct usb_ep           *in_ep, *out_ep;
  83        struct snd_card         *card;
  84        struct snd_rawmidi      *rmidi;
  85        u8                      ms_id;
  86
  87        struct snd_rawmidi_substream *out_substream[MAX_PORTS];
  88
  89        unsigned long           out_triggered;
  90        struct tasklet_struct   tasklet;
  91        unsigned int in_ports;
  92        unsigned int out_ports;
  93        int index;
  94        char *id;
  95        unsigned int buflen, qlen;
  96        /* This fifo is used as a buffer ring for pre-allocated IN usb_requests */
  97        DECLARE_KFIFO_PTR(in_req_fifo, struct usb_request *);
  98        spinlock_t transmit_lock;
  99        unsigned int in_last_port;
 100        unsigned char free_ref;
 101
 102        struct gmidi_in_port    in_ports_array[/* in_ports */];
 103};
 104
 105static inline struct f_midi *func_to_midi(struct usb_function *f)
 106{
 107        return container_of(f, struct f_midi, func);
 108}
 109
 110static void f_midi_transmit(struct f_midi *midi);
 111static void f_midi_rmidi_free(struct snd_rawmidi *rmidi);
 112static void f_midi_free_inst(struct usb_function_instance *f);
 113
 114DECLARE_UAC_AC_HEADER_DESCRIPTOR(1);
 115DECLARE_USB_MIDI_OUT_JACK_DESCRIPTOR(1);
 116DECLARE_USB_MS_ENDPOINT_DESCRIPTOR(16);
 117
 118/* B.3.1  Standard AC Interface Descriptor */
 119static struct usb_interface_descriptor ac_interface_desc = {
 120        .bLength =              USB_DT_INTERFACE_SIZE,
 121        .bDescriptorType =      USB_DT_INTERFACE,
 122        /* .bInterfaceNumber =  DYNAMIC */
 123        /* .bNumEndpoints =     DYNAMIC */
 124        .bInterfaceClass =      USB_CLASS_AUDIO,
 125        .bInterfaceSubClass =   USB_SUBCLASS_AUDIOCONTROL,
 126        /* .iInterface =        DYNAMIC */
 127};
 128
 129/* B.3.2  Class-Specific AC Interface Descriptor */
 130static struct uac1_ac_header_descriptor_1 ac_header_desc = {
 131        .bLength =              UAC_DT_AC_HEADER_SIZE(1),
 132        .bDescriptorType =      USB_DT_CS_INTERFACE,
 133        .bDescriptorSubtype =   USB_MS_HEADER,
 134        .bcdADC =               cpu_to_le16(0x0100),
 135        .wTotalLength =         cpu_to_le16(UAC_DT_AC_HEADER_SIZE(1)),
 136        .bInCollection =        1,
 137        /* .baInterfaceNr =     DYNAMIC */
 138};
 139
 140/* B.4.1  Standard MS Interface Descriptor */
 141static struct usb_interface_descriptor ms_interface_desc = {
 142        .bLength =              USB_DT_INTERFACE_SIZE,
 143        .bDescriptorType =      USB_DT_INTERFACE,
 144        /* .bInterfaceNumber =  DYNAMIC */
 145        .bNumEndpoints =        2,
 146        .bInterfaceClass =      USB_CLASS_AUDIO,
 147        .bInterfaceSubClass =   USB_SUBCLASS_MIDISTREAMING,
 148        /* .iInterface =        DYNAMIC */
 149};
 150
 151/* B.4.2  Class-Specific MS Interface Descriptor */
 152static struct usb_ms_header_descriptor ms_header_desc = {
 153        .bLength =              USB_DT_MS_HEADER_SIZE,
 154        .bDescriptorType =      USB_DT_CS_INTERFACE,
 155        .bDescriptorSubtype =   USB_MS_HEADER,
 156        .bcdMSC =               cpu_to_le16(0x0100),
 157        /* .wTotalLength =      DYNAMIC */
 158};
 159
 160/* B.5.1  Standard Bulk OUT Endpoint Descriptor */
 161static struct usb_endpoint_descriptor bulk_out_desc = {
 162        .bLength =              USB_DT_ENDPOINT_AUDIO_SIZE,
 163        .bDescriptorType =      USB_DT_ENDPOINT,
 164        .bEndpointAddress =     USB_DIR_OUT,
 165        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 166};
 167
 168static struct usb_ss_ep_comp_descriptor bulk_out_ss_comp_desc = {
 169        .bLength                = sizeof(bulk_out_ss_comp_desc),
 170        .bDescriptorType        = USB_DT_SS_ENDPOINT_COMP,
 171        /* .bMaxBurst           = 0, */
 172        /* .bmAttributes        = 0, */
 173};
 174
 175/* B.5.2  Class-specific MS Bulk OUT Endpoint Descriptor */
 176static struct usb_ms_endpoint_descriptor_16 ms_out_desc = {
 177        /* .bLength =           DYNAMIC */
 178        .bDescriptorType =      USB_DT_CS_ENDPOINT,
 179        .bDescriptorSubtype =   USB_MS_GENERAL,
 180        /* .bNumEmbMIDIJack =   DYNAMIC */
 181        /* .baAssocJackID =     DYNAMIC */
 182};
 183
 184/* B.6.1  Standard Bulk IN Endpoint Descriptor */
 185static struct usb_endpoint_descriptor bulk_in_desc = {
 186        .bLength =              USB_DT_ENDPOINT_AUDIO_SIZE,
 187        .bDescriptorType =      USB_DT_ENDPOINT,
 188        .bEndpointAddress =     USB_DIR_IN,
 189        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 190};
 191
 192static struct usb_ss_ep_comp_descriptor bulk_in_ss_comp_desc = {
 193        .bLength                = sizeof(bulk_in_ss_comp_desc),
 194        .bDescriptorType        = USB_DT_SS_ENDPOINT_COMP,
 195        /* .bMaxBurst           = 0, */
 196        /* .bmAttributes        = 0, */
 197};
 198
 199/* B.6.2  Class-specific MS Bulk IN Endpoint Descriptor */
 200static struct usb_ms_endpoint_descriptor_16 ms_in_desc = {
 201        /* .bLength =           DYNAMIC */
 202        .bDescriptorType =      USB_DT_CS_ENDPOINT,
 203        .bDescriptorSubtype =   USB_MS_GENERAL,
 204        /* .bNumEmbMIDIJack =   DYNAMIC */
 205        /* .baAssocJackID =     DYNAMIC */
 206};
 207
 208/* string IDs are assigned dynamically */
 209
 210#define STRING_FUNC_IDX                 0
 211
 212static struct usb_string midi_string_defs[] = {
 213        [STRING_FUNC_IDX].s = "MIDI function",
 214        {  } /* end of list */
 215};
 216
 217static struct usb_gadget_strings midi_stringtab = {
 218        .language       = 0x0409,       /* en-us */
 219        .strings        = midi_string_defs,
 220};
 221
 222static struct usb_gadget_strings *midi_strings[] = {
 223        &midi_stringtab,
 224        NULL,
 225};
 226
 227static inline struct usb_request *midi_alloc_ep_req(struct usb_ep *ep,
 228                                                    unsigned length)
 229{
 230        return alloc_ep_req(ep, length);
 231}
 232
 233static const uint8_t f_midi_cin_length[] = {
 234        0, 0, 2, 3, 3, 1, 2, 3, 3, 3, 3, 3, 2, 2, 3, 1
 235};
 236
 237/*
 238 * Receives a chunk of MIDI data.
 239 */
 240static void f_midi_read_data(struct usb_ep *ep, int cable,
 241                             uint8_t *data, int length)
 242{
 243        struct f_midi *midi = ep->driver_data;
 244        struct snd_rawmidi_substream *substream = midi->out_substream[cable];
 245
 246        if (!substream)
 247                /* Nobody is listening - throw it on the floor. */
 248                return;
 249
 250        if (!test_bit(cable, &midi->out_triggered))
 251                return;
 252
 253        snd_rawmidi_receive(substream, data, length);
 254}
 255
 256static void f_midi_handle_out_data(struct usb_ep *ep, struct usb_request *req)
 257{
 258        unsigned int i;
 259        u8 *buf = req->buf;
 260
 261        for (i = 0; i + 3 < req->actual; i += 4)
 262                if (buf[i] != 0) {
 263                        int cable = buf[i] >> 4;
 264                        int length = f_midi_cin_length[buf[i] & 0x0f];
 265                        f_midi_read_data(ep, cable, &buf[i + 1], length);
 266                }
 267}
 268
 269static void
 270f_midi_complete(struct usb_ep *ep, struct usb_request *req)
 271{
 272        struct f_midi *midi = ep->driver_data;
 273        struct usb_composite_dev *cdev = midi->func.config->cdev;
 274        int status = req->status;
 275
 276        switch (status) {
 277        case 0:                  /* normal completion */
 278                if (ep == midi->out_ep) {
 279                        /* We received stuff. req is queued again, below */
 280                        f_midi_handle_out_data(ep, req);
 281                } else if (ep == midi->in_ep) {
 282                        /* Our transmit completed. See if there's more to go.
 283                         * f_midi_transmit eats req, don't queue it again. */
 284                        req->length = 0;
 285                        f_midi_transmit(midi);
 286                        return;
 287                }
 288                break;
 289
 290        /* this endpoint is normally active while we're configured */
 291        case -ECONNABORTED:     /* hardware forced ep reset */
 292        case -ECONNRESET:       /* request dequeued */
 293        case -ESHUTDOWN:        /* disconnect from host */
 294                VDBG(cdev, "%s gone (%d), %d/%d\n", ep->name, status,
 295                                req->actual, req->length);
 296                if (ep == midi->out_ep) {
 297                        f_midi_handle_out_data(ep, req);
 298                        /* We don't need to free IN requests because it's handled
 299                         * by the midi->in_req_fifo. */
 300                        free_ep_req(ep, req);
 301                }
 302                return;
 303
 304        case -EOVERFLOW:        /* buffer overrun on read means that
 305                                 * we didn't provide a big enough buffer.
 306                                 */
 307        default:
 308                DBG(cdev, "%s complete --> %d, %d/%d\n", ep->name,
 309                                status, req->actual, req->length);
 310                break;
 311        case -EREMOTEIO:        /* short read */
 312                break;
 313        }
 314
 315        status = usb_ep_queue(ep, req, GFP_ATOMIC);
 316        if (status) {
 317                ERROR(cdev, "kill %s:  resubmit %d bytes --> %d\n",
 318                                ep->name, req->length, status);
 319                usb_ep_set_halt(ep);
 320                /* FIXME recover later ... somehow */
 321        }
 322}
 323
 324static void f_midi_drop_out_substreams(struct f_midi *midi)
 325{
 326        unsigned int i;
 327
 328        for (i = 0; i < midi->in_ports; i++) {
 329                struct gmidi_in_port *port = midi->in_ports_array + i;
 330                struct snd_rawmidi_substream *substream = port->substream;
 331
 332                if (port->active && substream)
 333                        snd_rawmidi_drop_output(substream);
 334        }
 335}
 336
 337static int f_midi_start_ep(struct f_midi *midi,
 338                           struct usb_function *f,
 339                           struct usb_ep *ep)
 340{
 341        int err;
 342        struct usb_composite_dev *cdev = f->config->cdev;
 343
 344        usb_ep_disable(ep);
 345
 346        err = config_ep_by_speed(midi->gadget, f, ep);
 347        if (err) {
 348                ERROR(cdev, "can't configure %s: %d\n", ep->name, err);
 349                return err;
 350        }
 351
 352        err = usb_ep_enable(ep);
 353        if (err) {
 354                ERROR(cdev, "can't start %s: %d\n", ep->name, err);
 355                return err;
 356        }
 357
 358        ep->driver_data = midi;
 359
 360        return 0;
 361}
 362
 363static int f_midi_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 364{
 365        struct f_midi *midi = func_to_midi(f);
 366        unsigned i;
 367        int err;
 368
 369        /* we only set alt for MIDIStreaming interface */
 370        if (intf != midi->ms_id)
 371                return 0;
 372
 373        err = f_midi_start_ep(midi, f, midi->in_ep);
 374        if (err)
 375                return err;
 376
 377        err = f_midi_start_ep(midi, f, midi->out_ep);
 378        if (err)
 379                return err;
 380
 381        /* pre-allocate write usb requests to use on f_midi_transmit. */
 382        while (kfifo_avail(&midi->in_req_fifo)) {
 383                struct usb_request *req =
 384                        midi_alloc_ep_req(midi->in_ep, midi->buflen);
 385
 386                if (req == NULL)
 387                        return -ENOMEM;
 388
 389                req->length = 0;
 390                req->complete = f_midi_complete;
 391
 392                kfifo_put(&midi->in_req_fifo, req);
 393        }
 394
 395        /* allocate a bunch of read buffers and queue them all at once. */
 396        for (i = 0; i < midi->qlen && err == 0; i++) {
 397                struct usb_request *req =
 398                        midi_alloc_ep_req(midi->out_ep, midi->buflen);
 399
 400                if (req == NULL)
 401                        return -ENOMEM;
 402
 403                req->complete = f_midi_complete;
 404                err = usb_ep_queue(midi->out_ep, req, GFP_ATOMIC);
 405                if (err) {
 406                        ERROR(midi, "%s: couldn't enqueue request: %d\n",
 407                                    midi->out_ep->name, err);
 408                        if (req->buf != NULL)
 409                                free_ep_req(midi->out_ep, req);
 410                        return err;
 411                }
 412        }
 413
 414        return 0;
 415}
 416
 417static void f_midi_disable(struct usb_function *f)
 418{
 419        struct f_midi *midi = func_to_midi(f);
 420        struct usb_composite_dev *cdev = f->config->cdev;
 421        struct usb_request *req = NULL;
 422
 423        DBG(cdev, "disable\n");
 424
 425        /*
 426         * just disable endpoints, forcing completion of pending i/o.
 427         * all our completion handlers free their requests in this case.
 428         */
 429        usb_ep_disable(midi->in_ep);
 430        usb_ep_disable(midi->out_ep);
 431
 432        /* release IN requests */
 433        while (kfifo_get(&midi->in_req_fifo, &req))
 434                free_ep_req(midi->in_ep, req);
 435
 436        f_midi_drop_out_substreams(midi);
 437}
 438
 439static int f_midi_snd_free(struct snd_device *device)
 440{
 441        return 0;
 442}
 443
 444/*
 445 * Converts MIDI commands to USB MIDI packets.
 446 */
 447static void f_midi_transmit_byte(struct usb_request *req,
 448                                 struct gmidi_in_port *port, uint8_t b)
 449{
 450        uint8_t p[4] = { port->cable << 4, 0, 0, 0 };
 451        uint8_t next_state = STATE_INITIAL;
 452
 453        switch (b) {
 454        case 0xf8 ... 0xff:
 455                /* System Real-Time Messages */
 456                p[0] |= 0x0f;
 457                p[1] = b;
 458                next_state = port->state;
 459                port->state = STATE_REAL_TIME;
 460                break;
 461
 462        case 0xf7:
 463                /* End of SysEx */
 464                switch (port->state) {
 465                case STATE_SYSEX_0:
 466                        p[0] |= 0x05;
 467                        p[1] = 0xf7;
 468                        next_state = STATE_FINISHED;
 469                        break;
 470                case STATE_SYSEX_1:
 471                        p[0] |= 0x06;
 472                        p[1] = port->data[0];
 473                        p[2] = 0xf7;
 474                        next_state = STATE_FINISHED;
 475                        break;
 476                case STATE_SYSEX_2:
 477                        p[0] |= 0x07;
 478                        p[1] = port->data[0];
 479                        p[2] = port->data[1];
 480                        p[3] = 0xf7;
 481                        next_state = STATE_FINISHED;
 482                        break;
 483                default:
 484                        /* Ignore byte */
 485                        next_state = port->state;
 486                        port->state = STATE_INITIAL;
 487                }
 488                break;
 489
 490        case 0xf0 ... 0xf6:
 491                /* System Common Messages */
 492                port->data[0] = port->data[1] = 0;
 493                port->state = STATE_INITIAL;
 494                switch (b) {
 495                case 0xf0:
 496                        port->data[0] = b;
 497                        port->data[1] = 0;
 498                        next_state = STATE_SYSEX_1;
 499                        break;
 500                case 0xf1:
 501                case 0xf3:
 502                        port->data[0] = b;
 503                        next_state = STATE_1PARAM;
 504                        break;
 505                case 0xf2:
 506                        port->data[0] = b;
 507                        next_state = STATE_2PARAM_1;
 508                        break;
 509                case 0xf4:
 510                case 0xf5:
 511                        next_state = STATE_INITIAL;
 512                        break;
 513                case 0xf6:
 514                        p[0] |= 0x05;
 515                        p[1] = 0xf6;
 516                        next_state = STATE_FINISHED;
 517                        break;
 518                }
 519                break;
 520
 521        case 0x80 ... 0xef:
 522                /*
 523                 * Channel Voice Messages, Channel Mode Messages
 524                 * and Control Change Messages.
 525                 */
 526                port->data[0] = b;
 527                port->data[1] = 0;
 528                port->state = STATE_INITIAL;
 529                if (b >= 0xc0 && b <= 0xdf)
 530                        next_state = STATE_1PARAM;
 531                else
 532                        next_state = STATE_2PARAM_1;
 533                break;
 534
 535        case 0x00 ... 0x7f:
 536                /* Message parameters */
 537                switch (port->state) {
 538                case STATE_1PARAM:
 539                        if (port->data[0] < 0xf0)
 540                                p[0] |= port->data[0] >> 4;
 541                        else
 542                                p[0] |= 0x02;
 543
 544                        p[1] = port->data[0];
 545                        p[2] = b;
 546                        /* This is to allow Running State Messages */
 547                        next_state = STATE_1PARAM;
 548                        break;
 549                case STATE_2PARAM_1:
 550                        port->data[1] = b;
 551                        next_state = STATE_2PARAM_2;
 552                        break;
 553                case STATE_2PARAM_2:
 554                        if (port->data[0] < 0xf0)
 555                                p[0] |= port->data[0] >> 4;
 556                        else
 557                                p[0] |= 0x03;
 558
 559                        p[1] = port->data[0];
 560                        p[2] = port->data[1];
 561                        p[3] = b;
 562                        /* This is to allow Running State Messages */
 563                        next_state = STATE_2PARAM_1;
 564                        break;
 565                case STATE_SYSEX_0:
 566                        port->data[0] = b;
 567                        next_state = STATE_SYSEX_1;
 568                        break;
 569                case STATE_SYSEX_1:
 570                        port->data[1] = b;
 571                        next_state = STATE_SYSEX_2;
 572                        break;
 573                case STATE_SYSEX_2:
 574                        p[0] |= 0x04;
 575                        p[1] = port->data[0];
 576                        p[2] = port->data[1];
 577                        p[3] = b;
 578                        next_state = STATE_SYSEX_0;
 579                        break;
 580                }
 581                break;
 582        }
 583
 584        /* States where we have to write into the USB request */
 585        if (next_state == STATE_FINISHED ||
 586            port->state == STATE_SYSEX_2 ||
 587            port->state == STATE_1PARAM ||
 588            port->state == STATE_2PARAM_2 ||
 589            port->state == STATE_REAL_TIME) {
 590
 591                unsigned int length = req->length;
 592                u8 *buf = (u8 *)req->buf + length;
 593
 594                memcpy(buf, p, sizeof(p));
 595                req->length = length + sizeof(p);
 596
 597                if (next_state == STATE_FINISHED) {
 598                        next_state = STATE_INITIAL;
 599                        port->data[0] = port->data[1] = 0;
 600                }
 601        }
 602
 603        port->state = next_state;
 604}
 605
 606static int f_midi_do_transmit(struct f_midi *midi, struct usb_ep *ep)
 607{
 608        struct usb_request *req = NULL;
 609        unsigned int len, i;
 610        bool active = false;
 611        int err;
 612
 613        /*
 614         * We peek the request in order to reuse it if it fails to enqueue on
 615         * its endpoint
 616         */
 617        len = kfifo_peek(&midi->in_req_fifo, &req);
 618        if (len != 1) {
 619                ERROR(midi, "%s: Couldn't get usb request\n", __func__);
 620                return -1;
 621        }
 622
 623        /*
 624         * If buffer overrun, then we ignore this transmission.
 625         * IMPORTANT: This will cause the user-space rawmidi device to block
 626         * until a) usb requests have been completed or b) snd_rawmidi_write()
 627         * times out.
 628         */
 629        if (req->length > 0)
 630                return 0;
 631
 632        for (i = midi->in_last_port; i < midi->in_ports; ++i) {
 633                struct gmidi_in_port *port = midi->in_ports_array + i;
 634                struct snd_rawmidi_substream *substream = port->substream;
 635
 636                if (!port->active || !substream)
 637                        continue;
 638
 639                while (req->length + 3 < midi->buflen) {
 640                        uint8_t b;
 641
 642                        if (snd_rawmidi_transmit(substream, &b, 1) != 1) {
 643                                port->active = 0;
 644                                break;
 645                        }
 646                        f_midi_transmit_byte(req, port, b);
 647                }
 648
 649                active = !!port->active;
 650                if (active)
 651                        break;
 652        }
 653        midi->in_last_port = active ? i : 0;
 654
 655        if (req->length <= 0)
 656                goto done;
 657
 658        err = usb_ep_queue(ep, req, GFP_ATOMIC);
 659        if (err < 0) {
 660                ERROR(midi, "%s failed to queue req: %d\n",
 661                      midi->in_ep->name, err);
 662                req->length = 0; /* Re-use request next time. */
 663        } else {
 664                /* Upon success, put request at the back of the queue. */
 665                kfifo_skip(&midi->in_req_fifo);
 666                kfifo_put(&midi->in_req_fifo, req);
 667        }
 668
 669done:
 670        return active;
 671}
 672
 673static void f_midi_transmit(struct f_midi *midi)
 674{
 675        struct usb_ep *ep = midi->in_ep;
 676        int ret;
 677        unsigned long flags;
 678
 679        /* We only care about USB requests if IN endpoint is enabled */
 680        if (!ep || !ep->enabled)
 681                goto drop_out;
 682
 683        spin_lock_irqsave(&midi->transmit_lock, flags);
 684
 685        do {
 686                ret = f_midi_do_transmit(midi, ep);
 687                if (ret < 0) {
 688                        spin_unlock_irqrestore(&midi->transmit_lock, flags);
 689                        goto drop_out;
 690                }
 691        } while (ret);
 692
 693        spin_unlock_irqrestore(&midi->transmit_lock, flags);
 694
 695        return;
 696
 697drop_out:
 698        f_midi_drop_out_substreams(midi);
 699}
 700
 701static void f_midi_in_tasklet(unsigned long data)
 702{
 703        struct f_midi *midi = (struct f_midi *) data;
 704        f_midi_transmit(midi);
 705}
 706
 707static int f_midi_in_open(struct snd_rawmidi_substream *substream)
 708{
 709        struct f_midi *midi = substream->rmidi->private_data;
 710        struct gmidi_in_port *port;
 711
 712        if (substream->number >= midi->in_ports)
 713                return -EINVAL;
 714
 715        VDBG(midi, "%s()\n", __func__);
 716        port = midi->in_ports_array + substream->number;
 717        port->substream = substream;
 718        port->state = STATE_INITIAL;
 719        return 0;
 720}
 721
 722static int f_midi_in_close(struct snd_rawmidi_substream *substream)
 723{
 724        struct f_midi *midi = substream->rmidi->private_data;
 725
 726        VDBG(midi, "%s()\n", __func__);
 727        return 0;
 728}
 729
 730static void f_midi_in_trigger(struct snd_rawmidi_substream *substream, int up)
 731{
 732        struct f_midi *midi = substream->rmidi->private_data;
 733
 734        if (substream->number >= midi->in_ports)
 735                return;
 736
 737        VDBG(midi, "%s() %d\n", __func__, up);
 738        midi->in_ports_array[substream->number].active = up;
 739        if (up)
 740                tasklet_hi_schedule(&midi->tasklet);
 741}
 742
 743static int f_midi_out_open(struct snd_rawmidi_substream *substream)
 744{
 745        struct f_midi *midi = substream->rmidi->private_data;
 746
 747        if (substream->number >= MAX_PORTS)
 748                return -EINVAL;
 749
 750        VDBG(midi, "%s()\n", __func__);
 751        midi->out_substream[substream->number] = substream;
 752        return 0;
 753}
 754
 755static int f_midi_out_close(struct snd_rawmidi_substream *substream)
 756{
 757        struct f_midi *midi = substream->rmidi->private_data;
 758
 759        VDBG(midi, "%s()\n", __func__);
 760        return 0;
 761}
 762
 763static void f_midi_out_trigger(struct snd_rawmidi_substream *substream, int up)
 764{
 765        struct f_midi *midi = substream->rmidi->private_data;
 766
 767        VDBG(midi, "%s()\n", __func__);
 768
 769        if (up)
 770                set_bit(substream->number, &midi->out_triggered);
 771        else
 772                clear_bit(substream->number, &midi->out_triggered);
 773}
 774
 775static const struct snd_rawmidi_ops gmidi_in_ops = {
 776        .open = f_midi_in_open,
 777        .close = f_midi_in_close,
 778        .trigger = f_midi_in_trigger,
 779};
 780
 781static const struct snd_rawmidi_ops gmidi_out_ops = {
 782        .open = f_midi_out_open,
 783        .close = f_midi_out_close,
 784        .trigger = f_midi_out_trigger
 785};
 786
 787static inline void f_midi_unregister_card(struct f_midi *midi)
 788{
 789        if (midi->card) {
 790                snd_card_free(midi->card);
 791                midi->card = NULL;
 792        }
 793}
 794
 795/* register as a sound "card" */
 796static int f_midi_register_card(struct f_midi *midi)
 797{
 798        struct snd_card *card;
 799        struct snd_rawmidi *rmidi;
 800        int err;
 801        static struct snd_device_ops ops = {
 802                .dev_free = f_midi_snd_free,
 803        };
 804
 805        err = snd_card_new(&midi->gadget->dev, midi->index, midi->id,
 806                           THIS_MODULE, 0, &card);
 807        if (err < 0) {
 808                ERROR(midi, "snd_card_new() failed\n");
 809                goto fail;
 810        }
 811        midi->card = card;
 812
 813        err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, midi, &ops);
 814        if (err < 0) {
 815                ERROR(midi, "snd_device_new() failed: error %d\n", err);
 816                goto fail;
 817        }
 818
 819        strcpy(card->driver, f_midi_longname);
 820        strcpy(card->longname, f_midi_longname);
 821        strcpy(card->shortname, f_midi_shortname);
 822
 823        /* Set up rawmidi */
 824        snd_component_add(card, "MIDI");
 825        err = snd_rawmidi_new(card, card->longname, 0,
 826                              midi->out_ports, midi->in_ports, &rmidi);
 827        if (err < 0) {
 828                ERROR(midi, "snd_rawmidi_new() failed: error %d\n", err);
 829                goto fail;
 830        }
 831        midi->rmidi = rmidi;
 832        midi->in_last_port = 0;
 833        strcpy(rmidi->name, card->shortname);
 834        rmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
 835                            SNDRV_RAWMIDI_INFO_INPUT |
 836                            SNDRV_RAWMIDI_INFO_DUPLEX;
 837        rmidi->private_data = midi;
 838        rmidi->private_free = f_midi_rmidi_free;
 839        midi->free_ref++;
 840
 841        /*
 842         * Yes, rawmidi OUTPUT = USB IN, and rawmidi INPUT = USB OUT.
 843         * It's an upside-down world being a gadget.
 844         */
 845        snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &gmidi_in_ops);
 846        snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &gmidi_out_ops);
 847
 848        /* register it - we're ready to go */
 849        err = snd_card_register(card);
 850        if (err < 0) {
 851                ERROR(midi, "snd_card_register() failed\n");
 852                goto fail;
 853        }
 854
 855        VDBG(midi, "%s() finished ok\n", __func__);
 856        return 0;
 857
 858fail:
 859        f_midi_unregister_card(midi);
 860        return err;
 861}
 862
 863/* MIDI function driver setup/binding */
 864
 865static int f_midi_bind(struct usb_configuration *c, struct usb_function *f)
 866{
 867        struct usb_descriptor_header **midi_function;
 868        struct usb_midi_in_jack_descriptor jack_in_ext_desc[MAX_PORTS];
 869        struct usb_midi_in_jack_descriptor jack_in_emb_desc[MAX_PORTS];
 870        struct usb_midi_out_jack_descriptor_1 jack_out_ext_desc[MAX_PORTS];
 871        struct usb_midi_out_jack_descriptor_1 jack_out_emb_desc[MAX_PORTS];
 872        struct usb_composite_dev *cdev = c->cdev;
 873        struct f_midi *midi = func_to_midi(f);
 874        struct usb_string *us;
 875        int status, n, jack = 1, i = 0, endpoint_descriptor_index = 0;
 876
 877        midi->gadget = cdev->gadget;
 878        tasklet_init(&midi->tasklet, f_midi_in_tasklet, (unsigned long) midi);
 879        status = f_midi_register_card(midi);
 880        if (status < 0)
 881                goto fail_register;
 882
 883        /* maybe allocate device-global string ID */
 884        us = usb_gstrings_attach(c->cdev, midi_strings,
 885                                 ARRAY_SIZE(midi_string_defs));
 886        if (IS_ERR(us)) {
 887                status = PTR_ERR(us);
 888                goto fail;
 889        }
 890        ac_interface_desc.iInterface = us[STRING_FUNC_IDX].id;
 891
 892        /* We have two interfaces, AudioControl and MIDIStreaming */
 893        status = usb_interface_id(c, f);
 894        if (status < 0)
 895                goto fail;
 896        ac_interface_desc.bInterfaceNumber = status;
 897
 898        status = usb_interface_id(c, f);
 899        if (status < 0)
 900                goto fail;
 901        ms_interface_desc.bInterfaceNumber = status;
 902        ac_header_desc.baInterfaceNr[0] = status;
 903        midi->ms_id = status;
 904
 905        status = -ENODEV;
 906
 907        /* allocate instance-specific endpoints */
 908        midi->in_ep = usb_ep_autoconfig(cdev->gadget, &bulk_in_desc);
 909        if (!midi->in_ep)
 910                goto fail;
 911
 912        midi->out_ep = usb_ep_autoconfig(cdev->gadget, &bulk_out_desc);
 913        if (!midi->out_ep)
 914                goto fail;
 915
 916        /* allocate temporary function list */
 917        midi_function = kcalloc((MAX_PORTS * 4) + 11, sizeof(*midi_function),
 918                                GFP_KERNEL);
 919        if (!midi_function) {
 920                status = -ENOMEM;
 921                goto fail;
 922        }
 923
 924        /*
 925         * construct the function's descriptor set. As the number of
 926         * input and output MIDI ports is configurable, we have to do
 927         * it that way.
 928         */
 929
 930        /* add the headers - these are always the same */
 931        midi_function[i++] = (struct usb_descriptor_header *) &ac_interface_desc;
 932        midi_function[i++] = (struct usb_descriptor_header *) &ac_header_desc;
 933        midi_function[i++] = (struct usb_descriptor_header *) &ms_interface_desc;
 934
 935        /* calculate the header's wTotalLength */
 936        n = USB_DT_MS_HEADER_SIZE
 937                + (midi->in_ports + midi->out_ports) *
 938                        (USB_DT_MIDI_IN_SIZE + USB_DT_MIDI_OUT_SIZE(1));
 939        ms_header_desc.wTotalLength = cpu_to_le16(n);
 940
 941        midi_function[i++] = (struct usb_descriptor_header *) &ms_header_desc;
 942
 943        /* configure the external IN jacks, each linked to an embedded OUT jack */
 944        for (n = 0; n < midi->in_ports; n++) {
 945                struct usb_midi_in_jack_descriptor *in_ext = &jack_in_ext_desc[n];
 946                struct usb_midi_out_jack_descriptor_1 *out_emb = &jack_out_emb_desc[n];
 947
 948                in_ext->bLength                 = USB_DT_MIDI_IN_SIZE;
 949                in_ext->bDescriptorType         = USB_DT_CS_INTERFACE;
 950                in_ext->bDescriptorSubtype      = USB_MS_MIDI_IN_JACK;
 951                in_ext->bJackType               = USB_MS_EXTERNAL;
 952                in_ext->bJackID                 = jack++;
 953                in_ext->iJack                   = 0;
 954                midi_function[i++] = (struct usb_descriptor_header *) in_ext;
 955
 956                out_emb->bLength                = USB_DT_MIDI_OUT_SIZE(1);
 957                out_emb->bDescriptorType        = USB_DT_CS_INTERFACE;
 958                out_emb->bDescriptorSubtype     = USB_MS_MIDI_OUT_JACK;
 959                out_emb->bJackType              = USB_MS_EMBEDDED;
 960                out_emb->bJackID                = jack++;
 961                out_emb->bNrInputPins           = 1;
 962                out_emb->pins[0].baSourcePin    = 1;
 963                out_emb->pins[0].baSourceID     = in_ext->bJackID;
 964                out_emb->iJack                  = 0;
 965                midi_function[i++] = (struct usb_descriptor_header *) out_emb;
 966
 967                /* link it to the endpoint */
 968                ms_in_desc.baAssocJackID[n] = out_emb->bJackID;
 969        }
 970
 971        /* configure the external OUT jacks, each linked to an embedded IN jack */
 972        for (n = 0; n < midi->out_ports; n++) {
 973                struct usb_midi_in_jack_descriptor *in_emb = &jack_in_emb_desc[n];
 974                struct usb_midi_out_jack_descriptor_1 *out_ext = &jack_out_ext_desc[n];
 975
 976                in_emb->bLength                 = USB_DT_MIDI_IN_SIZE;
 977                in_emb->bDescriptorType         = USB_DT_CS_INTERFACE;
 978                in_emb->bDescriptorSubtype      = USB_MS_MIDI_IN_JACK;
 979                in_emb->bJackType               = USB_MS_EMBEDDED;
 980                in_emb->bJackID                 = jack++;
 981                in_emb->iJack                   = 0;
 982                midi_function[i++] = (struct usb_descriptor_header *) in_emb;
 983
 984                out_ext->bLength =              USB_DT_MIDI_OUT_SIZE(1);
 985                out_ext->bDescriptorType =      USB_DT_CS_INTERFACE;
 986                out_ext->bDescriptorSubtype =   USB_MS_MIDI_OUT_JACK;
 987                out_ext->bJackType =            USB_MS_EXTERNAL;
 988                out_ext->bJackID =              jack++;
 989                out_ext->bNrInputPins =         1;
 990                out_ext->iJack =                0;
 991                out_ext->pins[0].baSourceID =   in_emb->bJackID;
 992                out_ext->pins[0].baSourcePin =  1;
 993                midi_function[i++] = (struct usb_descriptor_header *) out_ext;
 994
 995                /* link it to the endpoint */
 996                ms_out_desc.baAssocJackID[n] = in_emb->bJackID;
 997        }
 998
 999        /* configure the endpoint descriptors ... */
1000        ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
1001        ms_out_desc.bNumEmbMIDIJack = midi->in_ports;
1002
1003        ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
1004        ms_in_desc.bNumEmbMIDIJack = midi->out_ports;
1005
1006        /* ... and add them to the list */
1007        endpoint_descriptor_index = i;
1008        midi_function[i++] = (struct usb_descriptor_header *) &bulk_out_desc;
1009        midi_function[i++] = (struct usb_descriptor_header *) &ms_out_desc;
1010        midi_function[i++] = (struct usb_descriptor_header *) &bulk_in_desc;
1011        midi_function[i++] = (struct usb_descriptor_header *) &ms_in_desc;
1012        midi_function[i++] = NULL;
1013
1014        /*
1015         * support all relevant hardware speeds... we expect that when
1016         * hardware is dual speed, all bulk-capable endpoints work at
1017         * both speeds
1018         */
1019        /* copy descriptors, and track endpoint copies */
1020        f->fs_descriptors = usb_copy_descriptors(midi_function);
1021        if (!f->fs_descriptors)
1022                goto fail_f_midi;
1023
1024        if (gadget_is_dualspeed(c->cdev->gadget)) {
1025                bulk_in_desc.wMaxPacketSize = cpu_to_le16(512);
1026                bulk_out_desc.wMaxPacketSize = cpu_to_le16(512);
1027                f->hs_descriptors = usb_copy_descriptors(midi_function);
1028                if (!f->hs_descriptors)
1029                        goto fail_f_midi;
1030        }
1031
1032        if (gadget_is_superspeed(c->cdev->gadget)) {
1033                bulk_in_desc.wMaxPacketSize = cpu_to_le16(1024);
1034                bulk_out_desc.wMaxPacketSize = cpu_to_le16(1024);
1035                i = endpoint_descriptor_index;
1036                midi_function[i++] = (struct usb_descriptor_header *)
1037                                     &bulk_out_desc;
1038                midi_function[i++] = (struct usb_descriptor_header *)
1039                                     &bulk_out_ss_comp_desc;
1040                midi_function[i++] = (struct usb_descriptor_header *)
1041                                     &ms_out_desc;
1042                midi_function[i++] = (struct usb_descriptor_header *)
1043                                     &bulk_in_desc;
1044                midi_function[i++] = (struct usb_descriptor_header *)
1045                                     &bulk_in_ss_comp_desc;
1046                midi_function[i++] = (struct usb_descriptor_header *)
1047                                     &ms_in_desc;
1048                f->ss_descriptors = usb_copy_descriptors(midi_function);
1049                if (!f->ss_descriptors)
1050                        goto fail_f_midi;
1051        }
1052
1053        kfree(midi_function);
1054
1055        return 0;
1056
1057fail_f_midi:
1058        kfree(midi_function);
1059        usb_free_all_descriptors(f);
1060fail:
1061        f_midi_unregister_card(midi);
1062fail_register:
1063        ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
1064
1065        return status;
1066}
1067
1068static inline struct f_midi_opts *to_f_midi_opts(struct config_item *item)
1069{
1070        return container_of(to_config_group(item), struct f_midi_opts,
1071                            func_inst.group);
1072}
1073
1074static void midi_attr_release(struct config_item *item)
1075{
1076        struct f_midi_opts *opts = to_f_midi_opts(item);
1077
1078        usb_put_function_instance(&opts->func_inst);
1079}
1080
1081static struct configfs_item_operations midi_item_ops = {
1082        .release        = midi_attr_release,
1083};
1084
1085#define F_MIDI_OPT(name, test_limit, limit)                             \
1086static ssize_t f_midi_opts_##name##_show(struct config_item *item, char *page) \
1087{                                                                       \
1088        struct f_midi_opts *opts = to_f_midi_opts(item);                \
1089        int result;                                                     \
1090                                                                        \
1091        mutex_lock(&opts->lock);                                        \
1092        result = sprintf(page, "%d\n", opts->name);                     \
1093        mutex_unlock(&opts->lock);                                      \
1094                                                                        \
1095        return result;                                                  \
1096}                                                                       \
1097                                                                        \
1098static ssize_t f_midi_opts_##name##_store(struct config_item *item,     \
1099                                         const char *page, size_t len)  \
1100{                                                                       \
1101        struct f_midi_opts *opts = to_f_midi_opts(item);                \
1102        int ret;                                                        \
1103        u32 num;                                                        \
1104                                                                        \
1105        mutex_lock(&opts->lock);                                        \
1106        if (opts->refcnt > 1) {                                         \
1107                ret = -EBUSY;                                           \
1108                goto end;                                               \
1109        }                                                               \
1110                                                                        \
1111        ret = kstrtou32(page, 0, &num);                                 \
1112        if (ret)                                                        \
1113                goto end;                                               \
1114                                                                        \
1115        if (test_limit && num > limit) {                                \
1116                ret = -EINVAL;                                          \
1117                goto end;                                               \
1118        }                                                               \
1119        opts->name = num;                                               \
1120        ret = len;                                                      \
1121                                                                        \
1122end:                                                                    \
1123        mutex_unlock(&opts->lock);                                      \
1124        return ret;                                                     \
1125}                                                                       \
1126                                                                        \
1127CONFIGFS_ATTR(f_midi_opts_, name);
1128
1129F_MIDI_OPT(index, true, SNDRV_CARDS);
1130F_MIDI_OPT(buflen, false, 0);
1131F_MIDI_OPT(qlen, false, 0);
1132F_MIDI_OPT(in_ports, true, MAX_PORTS);
1133F_MIDI_OPT(out_ports, true, MAX_PORTS);
1134
1135static ssize_t f_midi_opts_id_show(struct config_item *item, char *page)
1136{
1137        struct f_midi_opts *opts = to_f_midi_opts(item);
1138        int result;
1139
1140        mutex_lock(&opts->lock);
1141        if (opts->id) {
1142                result = strlcpy(page, opts->id, PAGE_SIZE);
1143        } else {
1144                page[0] = 0;
1145                result = 0;
1146        }
1147
1148        mutex_unlock(&opts->lock);
1149
1150        return result;
1151}
1152
1153static ssize_t f_midi_opts_id_store(struct config_item *item,
1154                                    const char *page, size_t len)
1155{
1156        struct f_midi_opts *opts = to_f_midi_opts(item);
1157        int ret;
1158        char *c;
1159
1160        mutex_lock(&opts->lock);
1161        if (opts->refcnt > 1) {
1162                ret = -EBUSY;
1163                goto end;
1164        }
1165
1166        c = kstrndup(page, len, GFP_KERNEL);
1167        if (!c) {
1168                ret = -ENOMEM;
1169                goto end;
1170        }
1171        if (opts->id_allocated)
1172                kfree(opts->id);
1173        opts->id = c;
1174        opts->id_allocated = true;
1175        ret = len;
1176end:
1177        mutex_unlock(&opts->lock);
1178        return ret;
1179}
1180
1181CONFIGFS_ATTR(f_midi_opts_, id);
1182
1183static struct configfs_attribute *midi_attrs[] = {
1184        &f_midi_opts_attr_index,
1185        &f_midi_opts_attr_buflen,
1186        &f_midi_opts_attr_qlen,
1187        &f_midi_opts_attr_in_ports,
1188        &f_midi_opts_attr_out_ports,
1189        &f_midi_opts_attr_id,
1190        NULL,
1191};
1192
1193static const struct config_item_type midi_func_type = {
1194        .ct_item_ops    = &midi_item_ops,
1195        .ct_attrs       = midi_attrs,
1196        .ct_owner       = THIS_MODULE,
1197};
1198
1199static void f_midi_free_inst(struct usb_function_instance *f)
1200{
1201        struct f_midi_opts *opts;
1202        bool free = false;
1203
1204        opts = container_of(f, struct f_midi_opts, func_inst);
1205
1206        mutex_lock(&opts->lock);
1207        if (!--opts->refcnt) {
1208                free = true;
1209        }
1210        mutex_unlock(&opts->lock);
1211
1212        if (free) {
1213                if (opts->id_allocated)
1214                        kfree(opts->id);
1215                kfree(opts);
1216        }
1217}
1218
1219static struct usb_function_instance *f_midi_alloc_inst(void)
1220{
1221        struct f_midi_opts *opts;
1222
1223        opts = kzalloc(sizeof(*opts), GFP_KERNEL);
1224        if (!opts)
1225                return ERR_PTR(-ENOMEM);
1226
1227        mutex_init(&opts->lock);
1228        opts->func_inst.free_func_inst = f_midi_free_inst;
1229        opts->index = SNDRV_DEFAULT_IDX1;
1230        opts->id = SNDRV_DEFAULT_STR1;
1231        opts->buflen = 512;
1232        opts->qlen = 32;
1233        opts->in_ports = 1;
1234        opts->out_ports = 1;
1235        opts->refcnt = 1;
1236
1237        config_group_init_type_name(&opts->func_inst.group, "",
1238                                    &midi_func_type);
1239
1240        return &opts->func_inst;
1241}
1242
1243static void f_midi_free(struct usb_function *f)
1244{
1245        struct f_midi *midi;
1246        struct f_midi_opts *opts;
1247        bool free = false;
1248
1249        midi = func_to_midi(f);
1250        opts = container_of(f->fi, struct f_midi_opts, func_inst);
1251        mutex_lock(&opts->lock);
1252        if (!--midi->free_ref) {
1253                kfree(midi->id);
1254                kfifo_free(&midi->in_req_fifo);
1255                kfree(midi);
1256                free = true;
1257        }
1258        mutex_unlock(&opts->lock);
1259
1260        if (free)
1261                f_midi_free_inst(&opts->func_inst);
1262}
1263
1264static void f_midi_rmidi_free(struct snd_rawmidi *rmidi)
1265{
1266        f_midi_free(rmidi->private_data);
1267}
1268
1269static void f_midi_unbind(struct usb_configuration *c, struct usb_function *f)
1270{
1271        struct usb_composite_dev *cdev = f->config->cdev;
1272        struct f_midi *midi = func_to_midi(f);
1273        struct snd_card *card;
1274
1275        DBG(cdev, "unbind\n");
1276
1277        /* just to be sure */
1278        f_midi_disable(f);
1279
1280        card = midi->card;
1281        midi->card = NULL;
1282        if (card)
1283                snd_card_free_when_closed(card);
1284
1285        usb_free_all_descriptors(f);
1286}
1287
1288static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
1289{
1290        struct f_midi *midi = NULL;
1291        struct f_midi_opts *opts;
1292        int status, i;
1293
1294        opts = container_of(fi, struct f_midi_opts, func_inst);
1295
1296        mutex_lock(&opts->lock);
1297        /* sanity check */
1298        if (opts->in_ports > MAX_PORTS || opts->out_ports > MAX_PORTS) {
1299                status = -EINVAL;
1300                goto setup_fail;
1301        }
1302
1303        /* allocate and initialize one new instance */
1304        midi = kzalloc(struct_size(midi, in_ports_array, opts->in_ports),
1305                       GFP_KERNEL);
1306        if (!midi) {
1307                status = -ENOMEM;
1308                goto setup_fail;
1309        }
1310
1311        for (i = 0; i < opts->in_ports; i++)
1312                midi->in_ports_array[i].cable = i;
1313
1314        /* set up ALSA midi devices */
1315        midi->id = kstrdup(opts->id, GFP_KERNEL);
1316        if (opts->id && !midi->id) {
1317                status = -ENOMEM;
1318                goto setup_fail;
1319        }
1320        midi->in_ports = opts->in_ports;
1321        midi->out_ports = opts->out_ports;
1322        midi->index = opts->index;
1323        midi->buflen = opts->buflen;
1324        midi->qlen = opts->qlen;
1325        midi->in_last_port = 0;
1326        midi->free_ref = 1;
1327
1328        status = kfifo_alloc(&midi->in_req_fifo, midi->qlen, GFP_KERNEL);
1329        if (status)
1330                goto setup_fail;
1331
1332        spin_lock_init(&midi->transmit_lock);
1333
1334        ++opts->refcnt;
1335        mutex_unlock(&opts->lock);
1336
1337        midi->func.name         = "gmidi function";
1338        midi->func.bind         = f_midi_bind;
1339        midi->func.unbind       = f_midi_unbind;
1340        midi->func.set_alt      = f_midi_set_alt;
1341        midi->func.disable      = f_midi_disable;
1342        midi->func.free_func    = f_midi_free;
1343
1344        return &midi->func;
1345
1346setup_fail:
1347        mutex_unlock(&opts->lock);
1348        kfree(midi);
1349        return ERR_PTR(status);
1350}
1351
1352DECLARE_USB_FUNCTION_INIT(midi, f_midi_alloc_inst, f_midi_alloc);
1353