drivers/usb/gadget/function/f_hid.c

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