linux/drivers/usb/gadget/function/f_hid.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * f_hid.c -- USB HID function driver
   4 *
   5 * Copyright (C) 2010 Fabien Chouteau <fabien.chouteau@barco.com>
   6 */
   7
   8#include <linux/kernel.h>
   9#include <linux/module.h>
  10#include <linux/hid.h>
  11#include <linux/idr.h>
  12#include <linux/cdev.h>
  13#include <linux/mutex.h>
  14#include <linux/poll.h>
  15#include <linux/uaccess.h>
  16#include <linux/wait.h>
  17#include <linux/sched.h>
  18#include <linux/usb/g_hid.h>
  19
  20#include "u_f.h"
  21#include "u_hid.h"
  22
  23#define HIDG_MINORS     4
  24
  25static int major, minors;
  26static struct class *hidg_class;
  27static DEFINE_IDA(hidg_ida);
  28static DEFINE_MUTEX(hidg_ida_lock); /* protects access to hidg_ida */
  29
  30/*-------------------------------------------------------------------------*/
  31/*                            HID gadget struct                            */
  32
  33struct f_hidg_req_list {
  34        struct usb_request      *req;
  35        unsigned int            pos;
  36        struct list_head        list;
  37};
  38
  39struct f_hidg {
  40        /* configuration */
  41        unsigned char                   bInterfaceSubClass;
  42        unsigned char                   bInterfaceProtocol;
  43        unsigned char                   protocol;
  44        unsigned short                  report_desc_length;
  45        char                            *report_desc;
  46        unsigned short                  report_length;
  47
  48        /* recv report */
  49        struct list_head                completed_out_req;
  50        spinlock_t                      read_spinlock;
  51        wait_queue_head_t               read_queue;
  52        unsigned int                    qlen;
  53
  54        /* send report */
  55        spinlock_t                      write_spinlock;
  56        bool                            write_pending;
  57        wait_queue_head_t               write_queue;
  58        struct usb_request              *req;
  59
  60        int                             minor;
  61        struct cdev                     cdev;
  62        struct usb_function             func;
  63
  64        struct usb_ep                   *in_ep;
  65        struct usb_ep                   *out_ep;
  66};
  67
  68static inline struct f_hidg *func_to_hidg(struct usb_function *f)
  69{
  70        return container_of(f, struct f_hidg, func);
  71}
  72
  73/*-------------------------------------------------------------------------*/
  74/*                           Static descriptors                            */
  75
  76static struct usb_interface_descriptor hidg_interface_desc = {
  77        .bLength                = sizeof hidg_interface_desc,
  78        .bDescriptorType        = USB_DT_INTERFACE,
  79        /* .bInterfaceNumber    = DYNAMIC */
  80        .bAlternateSetting      = 0,
  81        .bNumEndpoints          = 2,
  82        .bInterfaceClass        = USB_CLASS_HID,
  83        /* .bInterfaceSubClass  = DYNAMIC */
  84        /* .bInterfaceProtocol  = DYNAMIC */
  85        /* .iInterface          = DYNAMIC */
  86};
  87
  88static struct hid_descriptor hidg_desc = {
  89        .bLength                        = sizeof hidg_desc,
  90        .bDescriptorType                = HID_DT_HID,
  91        .bcdHID                         = 0x0101,
  92        .bCountryCode                   = 0x00,
  93        .bNumDescriptors                = 0x1,
  94        /*.desc[0].bDescriptorType      = DYNAMIC */
  95        /*.desc[0].wDescriptorLenght    = DYNAMIC */
  96};
  97
  98/* Super-Speed Support */
  99
 100static struct usb_endpoint_descriptor hidg_ss_in_ep_desc = {
 101        .bLength                = USB_DT_ENDPOINT_SIZE,
 102        .bDescriptorType        = USB_DT_ENDPOINT,
 103        .bEndpointAddress       = USB_DIR_IN,
 104        .bmAttributes           = USB_ENDPOINT_XFER_INT,
 105        /*.wMaxPacketSize       = DYNAMIC */
 106        .bInterval              = 4, /* FIXME: Add this field in the
 107                                      * HID gadget configuration?
 108                                      * (struct hidg_func_descriptor)
 109                                      */
 110};
 111
 112static struct usb_ss_ep_comp_descriptor hidg_ss_in_comp_desc = {
 113        .bLength                = sizeof(hidg_ss_in_comp_desc),
 114        .bDescriptorType        = USB_DT_SS_ENDPOINT_COMP,
 115
 116        /* .bMaxBurst           = 0, */
 117        /* .bmAttributes        = 0, */
 118        /* .wBytesPerInterval   = DYNAMIC */
 119};
 120
 121static struct usb_endpoint_descriptor hidg_ss_out_ep_desc = {
 122        .bLength                = USB_DT_ENDPOINT_SIZE,
 123        .bDescriptorType        = USB_DT_ENDPOINT,
 124        .bEndpointAddress       = USB_DIR_OUT,
 125        .bmAttributes           = USB_ENDPOINT_XFER_INT,
 126        /*.wMaxPacketSize       = DYNAMIC */
 127        .bInterval              = 4, /* FIXME: Add this field in the
 128                                      * HID gadget configuration?
 129                                      * (struct hidg_func_descriptor)
 130                                      */
 131};
 132
 133static struct usb_ss_ep_comp_descriptor hidg_ss_out_comp_desc = {
 134        .bLength                = sizeof(hidg_ss_out_comp_desc),
 135        .bDescriptorType        = USB_DT_SS_ENDPOINT_COMP,
 136
 137        /* .bMaxBurst           = 0, */
 138        /* .bmAttributes        = 0, */
 139        /* .wBytesPerInterval   = DYNAMIC */
 140};
 141
 142static struct usb_descriptor_header *hidg_ss_descriptors[] = {
 143        (struct usb_descriptor_header *)&hidg_interface_desc,
 144        (struct usb_descriptor_header *)&hidg_desc,
 145        (struct usb_descriptor_header *)&hidg_ss_in_ep_desc,
 146        (struct usb_descriptor_header *)&hidg_ss_in_comp_desc,
 147        (struct usb_descriptor_header *)&hidg_ss_out_ep_desc,
 148        (struct usb_descriptor_header *)&hidg_ss_out_comp_desc,
 149        NULL,
 150};
 151
 152/* High-Speed Support */
 153
 154static struct usb_endpoint_descriptor hidg_hs_in_ep_desc = {
 155        .bLength                = USB_DT_ENDPOINT_SIZE,
 156        .bDescriptorType        = USB_DT_ENDPOINT,
 157        .bEndpointAddress       = USB_DIR_IN,
 158        .bmAttributes           = USB_ENDPOINT_XFER_INT,
 159        /*.wMaxPacketSize       = DYNAMIC */
 160        .bInterval              = 4, /* FIXME: Add this field in the
 161                                      * HID gadget configuration?
 162                                      * (struct hidg_func_descriptor)
 163                                      */
 164};
 165
 166static struct usb_endpoint_descriptor hidg_hs_out_ep_desc = {
 167        .bLength                = USB_DT_ENDPOINT_SIZE,
 168        .bDescriptorType        = USB_DT_ENDPOINT,
 169        .bEndpointAddress       = USB_DIR_OUT,
 170        .bmAttributes           = USB_ENDPOINT_XFER_INT,
 171        /*.wMaxPacketSize       = DYNAMIC */
 172        .bInterval              = 4, /* FIXME: Add this field in the
 173                                      * HID gadget configuration?
 174                                      * (struct hidg_func_descriptor)
 175                                      */
 176};
 177
 178static struct usb_descriptor_header *hidg_hs_descriptors[] = {
 179        (struct usb_descriptor_header *)&hidg_interface_desc,
 180        (struct usb_descriptor_header *)&hidg_desc,
 181        (struct usb_descriptor_header *)&hidg_hs_in_ep_desc,
 182        (struct usb_descriptor_header *)&hidg_hs_out_ep_desc,
 183        NULL,
 184};
 185
 186/* Full-Speed Support */
 187
 188static struct usb_endpoint_descriptor hidg_fs_in_ep_desc = {
 189        .bLength                = USB_DT_ENDPOINT_SIZE,
 190        .bDescriptorType        = USB_DT_ENDPOINT,
 191        .bEndpointAddress       = USB_DIR_IN,
 192        .bmAttributes           = USB_ENDPOINT_XFER_INT,
 193        /*.wMaxPacketSize       = DYNAMIC */
 194        .bInterval              = 10, /* FIXME: Add this field in the
 195                                       * HID gadget configuration?
 196                                       * (struct hidg_func_descriptor)
 197                                       */
 198};
 199
 200static struct usb_endpoint_descriptor hidg_fs_out_ep_desc = {
 201        .bLength                = USB_DT_ENDPOINT_SIZE,
 202        .bDescriptorType        = USB_DT_ENDPOINT,
 203        .bEndpointAddress       = USB_DIR_OUT,
 204        .bmAttributes           = USB_ENDPOINT_XFER_INT,
 205        /*.wMaxPacketSize       = DYNAMIC */
 206        .bInterval              = 10, /* FIXME: Add this field in the
 207                                       * HID gadget configuration?
 208                                       * (struct hidg_func_descriptor)
 209                                       */
 210};
 211
 212static struct usb_descriptor_header *hidg_fs_descriptors[] = {
 213        (struct usb_descriptor_header *)&hidg_interface_desc,
 214        (struct usb_descriptor_header *)&hidg_desc,
 215        (struct usb_descriptor_header *)&hidg_fs_in_ep_desc,
 216        (struct usb_descriptor_header *)&hidg_fs_out_ep_desc,
 217        NULL,
 218};
 219
 220/*-------------------------------------------------------------------------*/
 221/*                                 Strings                                 */
 222
 223#define CT_FUNC_HID_IDX 0
 224
 225static struct usb_string ct_func_string_defs[] = {
 226        [CT_FUNC_HID_IDX].s     = "HID Interface",
 227        {},                     /* end of list */
 228};
 229
 230static struct usb_gadget_strings ct_func_string_table = {
 231        .language       = 0x0409,       /* en-US */
 232        .strings        = ct_func_string_defs,
 233};
 234
 235static struct usb_gadget_strings *ct_func_strings[] = {
 236        &ct_func_string_table,
 237        NULL,
 238};
 239
 240/*-------------------------------------------------------------------------*/
 241/*                              Char Device                                */
 242
 243static ssize_t f_hidg_read(struct file *file, char __user *buffer,
 244                        size_t count, loff_t *ptr)
 245{
 246        struct f_hidg *hidg = file->private_data;
 247        struct f_hidg_req_list *list;
 248        struct usb_request *req;
 249        unsigned long flags;
 250        int ret;
 251
 252        if (!count)
 253                return 0;
 254
 255        if (!access_ok(buffer, count))
 256                return -EFAULT;
 257
 258        spin_lock_irqsave(&hidg->read_spinlock, flags);
 259
 260#define READ_COND (!list_empty(&hidg->completed_out_req))
 261
 262        /* wait for at least one buffer to complete */
 263        while (!READ_COND) {
 264                spin_unlock_irqrestore(&hidg->read_spinlock, flags);
 265                if (file->f_flags & O_NONBLOCK)
 266                        return -EAGAIN;
 267
 268                if (wait_event_interruptible(hidg->read_queue, READ_COND))
 269                        return -ERESTARTSYS;
 270
 271                spin_lock_irqsave(&hidg->read_spinlock, flags);
 272        }
 273
 274        /* pick the first one */
 275        list = list_first_entry(&hidg->completed_out_req,
 276                                struct f_hidg_req_list, list);
 277
 278        /*
 279         * Remove this from list to protect it from beign free()
 280         * while host disables our function
 281         */
 282        list_del(&list->list);
 283
 284        req = list->req;
 285        count = min_t(unsigned int, count, req->actual - list->pos);
 286        spin_unlock_irqrestore(&hidg->read_spinlock, flags);
 287
 288        /* copy to user outside spinlock */
 289        count -= copy_to_user(buffer, req->buf + list->pos, count);
 290        list->pos += count;
 291
 292        /*
 293         * if this request is completely handled and transfered to
 294         * userspace, remove its entry from the list and requeue it
 295         * again. Otherwise, we will revisit it again upon the next
 296         * call, taking into account its current read position.
 297         */
 298        if (list->pos == req->actual) {
 299                kfree(list);
 300
 301                req->length = hidg->report_length;
 302                ret = usb_ep_queue(hidg->out_ep, req, GFP_KERNEL);
 303                if (ret < 0) {
 304                        free_ep_req(hidg->out_ep, req);
 305                        return ret;
 306                }
 307        } else {
 308                spin_lock_irqsave(&hidg->read_spinlock, flags);
 309                list_add(&list->list, &hidg->completed_out_req);
 310                spin_unlock_irqrestore(&hidg->read_spinlock, flags);
 311
 312                wake_up(&hidg->read_queue);
 313        }
 314
 315        return count;
 316}
 317
 318static void f_hidg_req_complete(struct usb_ep *ep, struct usb_request *req)
 319{
 320        struct f_hidg *hidg = (struct f_hidg *)ep->driver_data;
 321        unsigned long flags;
 322
 323        if (req->status != 0) {
 324                ERROR(hidg->func.config->cdev,
 325                        "End Point Request ERROR: %d\n", req->status);
 326        }
 327
 328        spin_lock_irqsave(&hidg->write_spinlock, flags);
 329        hidg->write_pending = 0;
 330        spin_unlock_irqrestore(&hidg->write_spinlock, flags);
 331        wake_up(&hidg->write_queue);
 332}
 333
 334static ssize_t f_hidg_write(struct file *file, const char __user *buffer,
 335                            size_t count, loff_t *offp)
 336{
 337        struct f_hidg *hidg  = file->private_data;
 338        struct usb_request *req;
 339        unsigned long flags;
 340        ssize_t status = -ENOMEM;
 341
 342        if (!access_ok(buffer, count))
 343                return -EFAULT;
 344
 345        spin_lock_irqsave(&hidg->write_spinlock, flags);
 346
 347#define WRITE_COND (!hidg->write_pending)
 348try_again:
 349        /* write queue */
 350        while (!WRITE_COND) {
 351                spin_unlock_irqrestore(&hidg->write_spinlock, flags);
 352                if (file->f_flags & O_NONBLOCK)
 353                        return -EAGAIN;
 354
 355                if (wait_event_interruptible_exclusive(
 356                                hidg->write_queue, WRITE_COND))
 357                        return -ERESTARTSYS;
 358
 359                spin_lock_irqsave(&hidg->write_spinlock, flags);
 360        }
 361
 362        hidg->write_pending = 1;
 363        req = hidg->req;
 364        count  = min_t(unsigned, count, hidg->report_length);
 365
 366        spin_unlock_irqrestore(&hidg->write_spinlock, flags);
 367        status = copy_from_user(req->buf, buffer, count);
 368
 369        if (status != 0) {
 370                ERROR(hidg->func.config->cdev,
 371                        "copy_from_user error\n");
 372                status = -EINVAL;
 373                goto release_write_pending;
 374        }
 375
 376        spin_lock_irqsave(&hidg->write_spinlock, flags);
 377
 378        /* when our function has been disabled by host */
 379        if (!hidg->req) {
 380                free_ep_req(hidg->in_ep, req);
 381                /*
 382                 * TODO
 383                 * Should we fail with error here?
 384                 */
 385                goto try_again;
 386        }
 387
 388        req->status   = 0;
 389        req->zero     = 0;
 390        req->length   = count;
 391        req->complete = f_hidg_req_complete;
 392        req->context  = hidg;
 393
 394        spin_unlock_irqrestore(&hidg->write_spinlock, flags);
 395
 396        status = usb_ep_queue(hidg->in_ep, req, GFP_ATOMIC);
 397        if (status < 0) {
 398                ERROR(hidg->func.config->cdev,
 399                        "usb_ep_queue error on int endpoint %zd\n", status);
 400                goto release_write_pending;
 401        } else {
 402                status = count;
 403        }
 404
 405        return status;
 406release_write_pending:
 407        spin_lock_irqsave(&hidg->write_spinlock, flags);
 408        hidg->write_pending = 0;
 409        spin_unlock_irqrestore(&hidg->write_spinlock, flags);
 410
 411        wake_up(&hidg->write_queue);
 412
 413        return status;
 414}
 415
 416static __poll_t f_hidg_poll(struct file *file, poll_table *wait)
 417{
 418        struct f_hidg   *hidg  = file->private_data;
 419        __poll_t        ret = 0;
 420
 421        poll_wait(file, &hidg->read_queue, wait);
 422        poll_wait(file, &hidg->write_queue, wait);
 423
 424        if (WRITE_COND)
 425                ret |= EPOLLOUT | EPOLLWRNORM;
 426
 427        if (READ_COND)
 428                ret |= EPOLLIN | EPOLLRDNORM;
 429
 430        return ret;
 431}
 432
 433#undef WRITE_COND
 434#undef READ_COND
 435
 436static int f_hidg_release(struct inode *inode, struct file *fd)
 437{
 438        fd->private_data = NULL;
 439        return 0;
 440}
 441
 442static int f_hidg_open(struct inode *inode, struct file *fd)
 443{
 444        struct f_hidg *hidg =
 445                container_of(inode->i_cdev, struct f_hidg, cdev);
 446
 447        fd->private_data = hidg;
 448
 449        return 0;
 450}
 451
 452/*-------------------------------------------------------------------------*/
 453/*                                usb_function                             */
 454
 455static inline struct usb_request *hidg_alloc_ep_req(struct usb_ep *ep,
 456                                                    unsigned length)
 457{
 458        return alloc_ep_req(ep, length);
 459}
 460
 461static void hidg_set_report_complete(struct usb_ep *ep, struct usb_request *req)
 462{
 463        struct f_hidg *hidg = (struct f_hidg *) req->context;
 464        struct usb_composite_dev *cdev = hidg->func.config->cdev;
 465        struct f_hidg_req_list *req_list;
 466        unsigned long flags;
 467
 468        switch (req->status) {
 469        case 0:
 470                req_list = kzalloc(sizeof(*req_list), GFP_ATOMIC);
 471                if (!req_list) {
 472                        ERROR(cdev, "Unable to allocate mem for req_list\n");
 473                        goto free_req;
 474                }
 475
 476                req_list->req = req;
 477
 478                spin_lock_irqsave(&hidg->read_spinlock, flags);
 479                list_add_tail(&req_list->list, &hidg->completed_out_req);
 480                spin_unlock_irqrestore(&hidg->read_spinlock, flags);
 481
 482                wake_up(&hidg->read_queue);
 483                break;
 484        default:
 485                ERROR(cdev, "Set report failed %d\n", req->status);
 486                /* FALLTHROUGH */
 487        case -ECONNABORTED:             /* hardware forced ep reset */
 488        case -ECONNRESET:               /* request dequeued */
 489        case -ESHUTDOWN:                /* disconnect from host */
 490free_req:
 491                free_ep_req(ep, req);
 492                return;
 493        }
 494}
 495
 496static int hidg_setup(struct usb_function *f,
 497                const struct usb_ctrlrequest *ctrl)
 498{
 499        struct f_hidg                   *hidg = func_to_hidg(f);
 500        struct usb_composite_dev        *cdev = f->config->cdev;
 501        struct usb_request              *req  = cdev->req;
 502        int status = 0;
 503        __u16 value, length;
 504
 505        value   = __le16_to_cpu(ctrl->wValue);
 506        length  = __le16_to_cpu(ctrl->wLength);
 507
 508        VDBG(cdev,
 509             "%s crtl_request : bRequestType:0x%x bRequest:0x%x Value:0x%x\n",
 510             __func__, ctrl->bRequestType, ctrl->bRequest, value);
 511
 512        switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
 513        case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
 514                  | HID_REQ_GET_REPORT):
 515                VDBG(cdev, "get_report\n");
 516
 517                /* send an empty report */
 518                length = min_t(unsigned, length, hidg->report_length);
 519                memset(req->buf, 0x0, length);
 520
 521                goto respond;
 522                break;
 523
 524        case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
 525                  | HID_REQ_GET_PROTOCOL):
 526                VDBG(cdev, "get_protocol\n");
 527                length = min_t(unsigned int, length, 1);
 528                ((u8 *) req->buf)[0] = hidg->protocol;
 529                goto respond;
 530                break;
 531
 532        case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
 533                  | HID_REQ_SET_REPORT):
 534                VDBG(cdev, "set_report | wLength=%d\n", ctrl->wLength);
 535                goto stall;
 536                break;
 537
 538        case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
 539                  | HID_REQ_SET_PROTOCOL):
 540                VDBG(cdev, "set_protocol\n");
 541                if (value > HID_REPORT_PROTOCOL)
 542                        goto stall;
 543                length = 0;
 544                /*
 545                 * We assume that programs implementing the Boot protocol
 546                 * are also compatible with the Report Protocol
 547                 */
 548                if (hidg->bInterfaceSubClass == USB_INTERFACE_SUBCLASS_BOOT) {
 549                        hidg->protocol = value;
 550                        goto respond;
 551                }
 552                goto stall;
 553                break;
 554
 555        case ((USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_INTERFACE) << 8
 556                  | USB_REQ_GET_DESCRIPTOR):
 557                switch (value >> 8) {
 558                case HID_DT_HID:
 559                {
 560                        struct hid_descriptor hidg_desc_copy = hidg_desc;
 561
 562                        VDBG(cdev, "USB_REQ_GET_DESCRIPTOR: HID\n");
 563                        hidg_desc_copy.desc[0].bDescriptorType = HID_DT_REPORT;
 564                        hidg_desc_copy.desc[0].wDescriptorLength =
 565                                cpu_to_le16(hidg->report_desc_length);
 566
 567                        length = min_t(unsigned short, length,
 568                                                   hidg_desc_copy.bLength);
 569                        memcpy(req->buf, &hidg_desc_copy, length);
 570                        goto respond;
 571                        break;
 572                }
 573                case HID_DT_REPORT:
 574                        VDBG(cdev, "USB_REQ_GET_DESCRIPTOR: REPORT\n");
 575                        length = min_t(unsigned short, length,
 576                                                   hidg->report_desc_length);
 577                        memcpy(req->buf, hidg->report_desc, length);
 578                        goto respond;
 579                        break;
 580
 581                default:
 582                        VDBG(cdev, "Unknown descriptor request 0x%x\n",
 583                                 value >> 8);
 584                        goto stall;
 585                        break;
 586                }
 587                break;
 588
 589        default:
 590                VDBG(cdev, "Unknown request 0x%x\n",
 591                         ctrl->bRequest);
 592                goto stall;
 593                break;
 594        }
 595
 596stall:
 597        return -EOPNOTSUPP;
 598
 599respond:
 600        req->zero = 0;
 601        req->length = length;
 602        status = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
 603        if (status < 0)
 604                ERROR(cdev, "usb_ep_queue error on ep0 %d\n", value);
 605        return status;
 606}
 607
 608static void hidg_disable(struct usb_function *f)
 609{
 610        struct f_hidg *hidg = func_to_hidg(f);
 611        struct f_hidg_req_list *list, *next;
 612        unsigned long flags;
 613
 614        usb_ep_disable(hidg->in_ep);
 615        usb_ep_disable(hidg->out_ep);
 616
 617        spin_lock_irqsave(&hidg->read_spinlock, flags);
 618        list_for_each_entry_safe(list, next, &hidg->completed_out_req, list) {
 619                free_ep_req(hidg->out_ep, list->req);
 620                list_del(&list->list);
 621                kfree(list);
 622        }
 623        spin_unlock_irqrestore(&hidg->read_spinlock, flags);
 624
 625        spin_lock_irqsave(&hidg->write_spinlock, flags);
 626        if (!hidg->write_pending) {
 627                free_ep_req(hidg->in_ep, hidg->req);
 628                hidg->write_pending = 1;
 629        }
 630
 631        hidg->req = NULL;
 632        spin_unlock_irqrestore(&hidg->write_spinlock, flags);
 633}
 634
 635static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 636{
 637        struct usb_composite_dev                *cdev = f->config->cdev;
 638        struct f_hidg                           *hidg = func_to_hidg(f);
 639        struct usb_request                      *req_in = NULL;
 640        unsigned long                           flags;
 641        int i, status = 0;
 642
 643        VDBG(cdev, "hidg_set_alt intf:%d alt:%d\n", intf, alt);
 644
 645        if (hidg->in_ep != NULL) {
 646                /* restart endpoint */
 647                usb_ep_disable(hidg->in_ep);
 648
 649                status = config_ep_by_speed(f->config->cdev->gadget, f,
 650                                            hidg->in_ep);
 651                if (status) {
 652                        ERROR(cdev, "config_ep_by_speed FAILED!\n");
 653                        goto fail;
 654                }
 655                status = usb_ep_enable(hidg->in_ep);
 656                if (status < 0) {
 657                        ERROR(cdev, "Enable IN endpoint FAILED!\n");
 658                        goto fail;
 659                }
 660                hidg->in_ep->driver_data = hidg;
 661
 662                req_in = hidg_alloc_ep_req(hidg->in_ep, hidg->report_length);
 663                if (!req_in) {
 664                        status = -ENOMEM;
 665                        goto disable_ep_in;
 666                }
 667        }
 668
 669
 670        if (hidg->out_ep != NULL) {
 671                /* restart endpoint */
 672                usb_ep_disable(hidg->out_ep);
 673
 674                status = config_ep_by_speed(f->config->cdev->gadget, f,
 675                                            hidg->out_ep);
 676                if (status) {
 677                        ERROR(cdev, "config_ep_by_speed FAILED!\n");
 678                        goto free_req_in;
 679                }
 680                status = usb_ep_enable(hidg->out_ep);
 681                if (status < 0) {
 682                        ERROR(cdev, "Enable OUT endpoint FAILED!\n");
 683                        goto free_req_in;
 684                }
 685                hidg->out_ep->driver_data = hidg;
 686
 687                /*
 688                 * allocate a bunch of read buffers and queue them all at once.
 689                 */
 690                for (i = 0; i < hidg->qlen && status == 0; i++) {
 691                        struct usb_request *req =
 692                                        hidg_alloc_ep_req(hidg->out_ep,
 693                                                          hidg->report_length);
 694                        if (req) {
 695                                req->complete = hidg_set_report_complete;
 696                                req->context  = hidg;
 697                                status = usb_ep_queue(hidg->out_ep, req,
 698                                                      GFP_ATOMIC);
 699                                if (status) {
 700                                        ERROR(cdev, "%s queue req --> %d\n",
 701                                                hidg->out_ep->name, status);
 702                                        free_ep_req(hidg->out_ep, req);
 703                                }
 704                        } else {
 705                                status = -ENOMEM;
 706                                goto disable_out_ep;
 707                        }
 708                }
 709        }
 710
 711        if (hidg->in_ep != NULL) {
 712                spin_lock_irqsave(&hidg->write_spinlock, flags);
 713                hidg->req = req_in;
 714                hidg->write_pending = 0;
 715                spin_unlock_irqrestore(&hidg->write_spinlock, flags);
 716
 717                wake_up(&hidg->write_queue);
 718        }
 719        return 0;
 720disable_out_ep:
 721        usb_ep_disable(hidg->out_ep);
 722free_req_in:
 723        if (req_in)
 724                free_ep_req(hidg->in_ep, req_in);
 725
 726disable_ep_in:
 727        if (hidg->in_ep)
 728                usb_ep_disable(hidg->in_ep);
 729
 730fail:
 731        return status;
 732}
 733
 734static const struct file_operations f_hidg_fops = {
 735        .owner          = THIS_MODULE,
 736        .open           = f_hidg_open,
 737        .release        = f_hidg_release,
 738        .write          = f_hidg_write,
 739        .read           = f_hidg_read,
 740        .poll           = f_hidg_poll,
 741        .llseek         = noop_llseek,
 742};
 743
 744static int hidg_bind(struct usb_configuration *c, struct usb_function *f)
 745{
 746        struct usb_ep           *ep;
 747        struct f_hidg           *hidg = func_to_hidg(f);
 748        struct usb_string       *us;
 749        struct device           *device;
 750        int                     status;
 751        dev_t                   dev;
 752
 753        /* maybe allocate device-global string IDs, and patch descriptors */
 754        us = usb_gstrings_attach(c->cdev, ct_func_strings,
 755                                 ARRAY_SIZE(ct_func_string_defs));
 756        if (IS_ERR(us))
 757                return PTR_ERR(us);
 758        hidg_interface_desc.iInterface = us[CT_FUNC_HID_IDX].id;
 759
 760        /* allocate instance-specific interface IDs, and patch descriptors */
 761        status = usb_interface_id(c, f);
 762        if (status < 0)
 763                goto fail;
 764        hidg_interface_desc.bInterfaceNumber = status;
 765
 766        /* allocate instance-specific endpoints */
 767        status = -ENODEV;
 768        ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_in_ep_desc);
 769        if (!ep)
 770                goto fail;
 771        hidg->in_ep = ep;
 772
 773        ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_out_ep_desc);
 774        if (!ep)
 775                goto fail;
 776        hidg->out_ep = ep;
 777
 778        /* set descriptor dynamic values */
 779        hidg_interface_desc.bInterfaceSubClass = hidg->bInterfaceSubClass;
 780        hidg_interface_desc.bInterfaceProtocol = hidg->bInterfaceProtocol;
 781        hidg->protocol = HID_REPORT_PROTOCOL;
 782        hidg_ss_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
 783        hidg_ss_in_comp_desc.wBytesPerInterval =
 784                                cpu_to_le16(hidg->report_length);
 785        hidg_hs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
 786        hidg_fs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
 787        hidg_ss_out_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
 788        hidg_ss_out_comp_desc.wBytesPerInterval =
 789                                cpu_to_le16(hidg->report_length);
 790        hidg_hs_out_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
 791        hidg_fs_out_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
 792        /*
 793         * We can use hidg_desc struct here but we should not relay
 794         * that its content won't change after returning from this function.
 795         */
 796        hidg_desc.desc[0].bDescriptorType = HID_DT_REPORT;
 797        hidg_desc.desc[0].wDescriptorLength =
 798                cpu_to_le16(hidg->report_desc_length);
 799
 800        hidg_hs_in_ep_desc.bEndpointAddress =
 801                hidg_fs_in_ep_desc.bEndpointAddress;
 802        hidg_hs_out_ep_desc.bEndpointAddress =
 803                hidg_fs_out_ep_desc.bEndpointAddress;
 804
 805        hidg_ss_in_ep_desc.bEndpointAddress =
 806                hidg_fs_in_ep_desc.bEndpointAddress;
 807        hidg_ss_out_ep_desc.bEndpointAddress =
 808                hidg_fs_out_ep_desc.bEndpointAddress;
 809
 810        status = usb_assign_descriptors(f, hidg_fs_descriptors,
 811                        hidg_hs_descriptors, hidg_ss_descriptors, NULL);
 812        if (status)
 813                goto fail;
 814
 815        spin_lock_init(&hidg->write_spinlock);
 816        hidg->write_pending = 1;
 817        hidg->req = NULL;
 818        spin_lock_init(&hidg->read_spinlock);
 819        init_waitqueue_head(&hidg->write_queue);
 820        init_waitqueue_head(&hidg->read_queue);
 821        INIT_LIST_HEAD(&hidg->completed_out_req);
 822
 823        /* create char device */
 824        cdev_init(&hidg->cdev, &f_hidg_fops);
 825        dev = MKDEV(major, hidg->minor);
 826        status = cdev_add(&hidg->cdev, dev, 1);
 827        if (status)
 828                goto fail_free_descs;
 829
 830        device = device_create(hidg_class, NULL, dev, NULL,
 831                               "%s%d", "hidg", hidg->minor);
 832        if (IS_ERR(device)) {
 833                status = PTR_ERR(device);
 834                goto del;
 835        }
 836
 837        return 0;
 838del:
 839        cdev_del(&hidg->cdev);
 840fail_free_descs:
 841        usb_free_all_descriptors(f);
 842fail:
 843        ERROR(f->config->cdev, "hidg_bind FAILED\n");
 844        if (hidg->req != NULL)
 845                free_ep_req(hidg->in_ep, hidg->req);
 846
 847        return status;
 848}
 849
 850static inline int hidg_get_minor(void)
 851{
 852        int ret;
 853
 854        ret = ida_simple_get(&hidg_ida, 0, 0, GFP_KERNEL);
 855        if (ret >= HIDG_MINORS) {
 856                ida_simple_remove(&hidg_ida, ret);
 857                ret = -ENODEV;
 858        }
 859
 860        return ret;
 861}
 862
 863static inline struct f_hid_opts *to_f_hid_opts(struct config_item *item)
 864{
 865        return container_of(to_config_group(item), struct f_hid_opts,
 866                            func_inst.group);
 867}
 868
 869static void hid_attr_release(struct config_item *item)
 870{
 871        struct f_hid_opts *opts = to_f_hid_opts(item);
 872
 873        usb_put_function_instance(&opts->func_inst);
 874}
 875
 876static struct configfs_item_operations hidg_item_ops = {
 877        .release        = hid_attr_release,
 878};
 879
 880#define F_HID_OPT(name, prec, limit)                                    \
 881static ssize_t f_hid_opts_##name##_show(struct config_item *item, char *page)\
 882{                                                                       \
 883        struct f_hid_opts *opts = to_f_hid_opts(item);                  \
 884        int result;                                                     \
 885                                                                        \
 886        mutex_lock(&opts->lock);                                        \
 887        result = sprintf(page, "%d\n", opts->name);                     \
 888        mutex_unlock(&opts->lock);                                      \
 889                                                                        \
 890        return result;                                                  \
 891}                                                                       \
 892                                                                        \
 893static ssize_t f_hid_opts_##name##_store(struct config_item *item,      \
 894                                         const char *page, size_t len)  \
 895{                                                                       \
 896        struct f_hid_opts *opts = to_f_hid_opts(item);                  \
 897        int ret;                                                        \
 898        u##prec num;                                                    \
 899                                                                        \
 900        mutex_lock(&opts->lock);                                        \
 901        if (opts->refcnt) {                                             \
 902                ret = -EBUSY;                                           \
 903                goto end;                                               \
 904        }                                                               \
 905                                                                        \
 906        ret = kstrtou##prec(page, 0, &num);                             \
 907        if (ret)                                                        \
 908                goto end;                                               \
 909                                                                        \
 910        if (num > limit) {                                              \
 911                ret = -EINVAL;                                          \
 912                goto end;                                               \
 913        }                                                               \
 914        opts->name = num;                                               \
 915        ret = len;                                                      \
 916                                                                        \
 917end:                                                                    \
 918        mutex_unlock(&opts->lock);                                      \
 919        return ret;                                                     \
 920}                                                                       \
 921                                                                        \
 922CONFIGFS_ATTR(f_hid_opts_, name)
 923
 924F_HID_OPT(subclass, 8, 255);
 925F_HID_OPT(protocol, 8, 255);
 926F_HID_OPT(report_length, 16, 65535);
 927
 928static ssize_t f_hid_opts_report_desc_show(struct config_item *item, char *page)
 929{
 930        struct f_hid_opts *opts = to_f_hid_opts(item);
 931        int result;
 932
 933        mutex_lock(&opts->lock);
 934        result = opts->report_desc_length;
 935        memcpy(page, opts->report_desc, opts->report_desc_length);
 936        mutex_unlock(&opts->lock);
 937
 938        return result;
 939}
 940
 941static ssize_t f_hid_opts_report_desc_store(struct config_item *item,
 942                                            const char *page, size_t len)
 943{
 944        struct f_hid_opts *opts = to_f_hid_opts(item);
 945        int ret = -EBUSY;
 946        char *d;
 947
 948        mutex_lock(&opts->lock);
 949
 950        if (opts->refcnt)
 951                goto end;
 952        if (len > PAGE_SIZE) {
 953                ret = -ENOSPC;
 954                goto end;
 955        }
 956        d = kmemdup(page, len, GFP_KERNEL);
 957        if (!d) {
 958                ret = -ENOMEM;
 959                goto end;
 960        }
 961        kfree(opts->report_desc);
 962        opts->report_desc = d;
 963        opts->report_desc_length = len;
 964        opts->report_desc_alloc = true;
 965        ret = len;
 966end:
 967        mutex_unlock(&opts->lock);
 968        return ret;
 969}
 970
 971CONFIGFS_ATTR(f_hid_opts_, report_desc);
 972
 973static ssize_t f_hid_opts_dev_show(struct config_item *item, char *page)
 974{
 975        struct f_hid_opts *opts = to_f_hid_opts(item);
 976
 977        return sprintf(page, "%d:%d\n", major, opts->minor);
 978}
 979
 980CONFIGFS_ATTR_RO(f_hid_opts_, dev);
 981
 982static struct configfs_attribute *hid_attrs[] = {
 983        &f_hid_opts_attr_subclass,
 984        &f_hid_opts_attr_protocol,
 985        &f_hid_opts_attr_report_length,
 986        &f_hid_opts_attr_report_desc,
 987        &f_hid_opts_attr_dev,
 988        NULL,
 989};
 990
 991static const struct config_item_type hid_func_type = {
 992        .ct_item_ops    = &hidg_item_ops,
 993        .ct_attrs       = hid_attrs,
 994        .ct_owner       = THIS_MODULE,
 995};
 996
 997static inline void hidg_put_minor(int minor)
 998{
 999        ida_simple_remove(&hidg_ida, minor);
1000}
1001
1002static void hidg_free_inst(struct usb_function_instance *f)
1003{
1004        struct f_hid_opts *opts;
1005
1006        opts = container_of(f, struct f_hid_opts, func_inst);
1007
1008        mutex_lock(&hidg_ida_lock);
1009
1010        hidg_put_minor(opts->minor);
1011        if (ida_is_empty(&hidg_ida))
1012                ghid_cleanup();
1013
1014        mutex_unlock(&hidg_ida_lock);
1015
1016        if (opts->report_desc_alloc)
1017                kfree(opts->report_desc);
1018
1019        kfree(opts);
1020}
1021
1022static struct usb_function_instance *hidg_alloc_inst(void)
1023{
1024        struct f_hid_opts *opts;
1025        struct usb_function_instance *ret;
1026        int status = 0;
1027
1028        opts = kzalloc(sizeof(*opts), GFP_KERNEL);
1029        if (!opts)
1030                return ERR_PTR(-ENOMEM);
1031        mutex_init(&opts->lock);
1032        opts->func_inst.free_func_inst = hidg_free_inst;
1033        ret = &opts->func_inst;
1034
1035        mutex_lock(&hidg_ida_lock);
1036
1037        if (ida_is_empty(&hidg_ida)) {
1038                status = ghid_setup(NULL, HIDG_MINORS);
1039                if (status)  {
1040                        ret = ERR_PTR(status);
1041                        kfree(opts);
1042                        goto unlock;
1043                }
1044        }
1045
1046        opts->minor = hidg_get_minor();
1047        if (opts->minor < 0) {
1048                ret = ERR_PTR(opts->minor);
1049                kfree(opts);
1050                if (ida_is_empty(&hidg_ida))
1051                        ghid_cleanup();
1052                goto unlock;
1053        }
1054        config_group_init_type_name(&opts->func_inst.group, "", &hid_func_type);
1055
1056unlock:
1057        mutex_unlock(&hidg_ida_lock);
1058        return ret;
1059}
1060
1061static void hidg_free(struct usb_function *f)
1062{
1063        struct f_hidg *hidg;
1064        struct f_hid_opts *opts;
1065
1066        hidg = func_to_hidg(f);
1067        opts = container_of(f->fi, struct f_hid_opts, func_inst);
1068        kfree(hidg->report_desc);
1069        kfree(hidg);
1070        mutex_lock(&opts->lock);
1071        --opts->refcnt;
1072        mutex_unlock(&opts->lock);
1073}
1074
1075static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)
1076{
1077        struct f_hidg *hidg = func_to_hidg(f);
1078
1079        device_destroy(hidg_class, MKDEV(major, hidg->minor));
1080        cdev_del(&hidg->cdev);
1081
1082        usb_free_all_descriptors(f);
1083}
1084
1085static struct usb_function *hidg_alloc(struct usb_function_instance *fi)
1086{
1087        struct f_hidg *hidg;
1088        struct f_hid_opts *opts;
1089
1090        /* allocate and initialize one new instance */
1091        hidg = kzalloc(sizeof(*hidg), GFP_KERNEL);
1092        if (!hidg)
1093                return ERR_PTR(-ENOMEM);
1094
1095        opts = container_of(fi, struct f_hid_opts, func_inst);
1096
1097        mutex_lock(&opts->lock);
1098        ++opts->refcnt;
1099
1100        hidg->minor = opts->minor;
1101        hidg->bInterfaceSubClass = opts->subclass;
1102        hidg->bInterfaceProtocol = opts->protocol;
1103        hidg->report_length = opts->report_length;
1104        hidg->report_desc_length = opts->report_desc_length;
1105        if (opts->report_desc) {
1106                hidg->report_desc = kmemdup(opts->report_desc,
1107                                            opts->report_desc_length,
1108                                            GFP_KERNEL);
1109                if (!hidg->report_desc) {
1110                        kfree(hidg);
1111                        mutex_unlock(&opts->lock);
1112                        return ERR_PTR(-ENOMEM);
1113                }
1114        }
1115
1116        mutex_unlock(&opts->lock);
1117
1118        hidg->func.name    = "hid";
1119        hidg->func.bind    = hidg_bind;
1120        hidg->func.unbind  = hidg_unbind;
1121        hidg->func.set_alt = hidg_set_alt;
1122        hidg->func.disable = hidg_disable;
1123        hidg->func.setup   = hidg_setup;
1124        hidg->func.free_func = hidg_free;
1125
1126        /* this could me made configurable at some point */
1127        hidg->qlen         = 4;
1128
1129        return &hidg->func;
1130}
1131
1132DECLARE_USB_FUNCTION_INIT(hid, hidg_alloc_inst, hidg_alloc);
1133MODULE_LICENSE("GPL");
1134MODULE_AUTHOR("Fabien Chouteau");
1135
1136int ghid_setup(struct usb_gadget *g, int count)
1137{
1138        int status;
1139        dev_t dev;
1140
1141        hidg_class = class_create(THIS_MODULE, "hidg");
1142        if (IS_ERR(hidg_class)) {
1143                status = PTR_ERR(hidg_class);
1144                hidg_class = NULL;
1145                return status;
1146        }
1147
1148        status = alloc_chrdev_region(&dev, 0, count, "hidg");
1149        if (status) {
1150                class_destroy(hidg_class);
1151                hidg_class = NULL;
1152                return status;
1153        }
1154
1155        major = MAJOR(dev);
1156        minors = count;
1157
1158        return 0;
1159}
1160
1161void ghid_cleanup(void)
1162{
1163        if (major) {
1164                unregister_chrdev_region(MKDEV(major, 0), minors);
1165                major = minors = 0;
1166        }
1167
1168        class_destroy(hidg_class);
1169        hidg_class = NULL;
1170}
1171