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         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
 318 static 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
 334 static 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)
 348 try_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;
 406 release_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
 416 static __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
 436 static int f_hidg_release(struct inode *inode, struct file *fd)
 437 {
 438         fd->private_data = NULL;
 439         return 0;
 440 }
 441
 442 static 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
 455 static 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
 461 static 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 */
 490 free_req:
 491                 free_ep_req(ep, req);
 492                 return;
 493         }
 494 }
 495
 496 static 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
 596 stall:
 597         return -EOPNOTSUPP;
 598
 599 respond:
 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
 608 static 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
 635 static 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;
 720 disable_out_ep:
 721         usb_ep_disable(hidg->out_ep);
 722 free_req_in:
 723         if (req_in)
 724                 free_ep_req(hidg->in_ep, req_in);
 725
 726 disable_ep_in:
 727         if (hidg->in_ep)
 728                 usb_ep_disable(hidg->in_ep);
 729
 730 fail:
 731         return status;
 732 }
 733
 734 static 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
 744 static 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;
 838 del:
 839         cdev_del(&hidg->cdev);
 840 fail_free_descs:
 841         usb_free_all_descriptors(f);
 842 fail:
 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
 850 static 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
 863 static 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
 869 static 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
 876 static struct configfs_item_operations hidg_item_ops = {
 877         .release        = hid_attr_release,
 878 };
 879
 880 #define F_HID_OPT(name, prec, limit)                                    \
 881 static 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                                                                         \
 893 static 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                                                                         \
 917 end:                                                                    \
 918         mutex_unlock(&opts->lock);                                      \
 919         return ret;                                                     \
 920 }                                                                       \
 921                                                                         \
 922 CONFIGFS_ATTR(f_hid_opts_, name)
 923
 924 F_HID_OPT(subclass, 8, 255);
 925 F_HID_OPT(protocol, 8, 255);
 926 F_HID_OPT(report_length, 16, 65535);
 927
 928 static 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
 941 static 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;
 966 end:
 967         mutex_unlock(&opts->lock);
 968         return ret;
 969 }
 970
 971 CONFIGFS_ATTR(f_hid_opts_, report_desc);
 972
 973 static 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
 980 CONFIGFS_ATTR_RO(f_hid_opts_, dev);
 981
 982 static 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
 991 static 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
 997 static inline void hidg_put_minor(int minor)
 998 {
 999         ida_simple_remove(&hidg_ida, minor);
1000 }
1001
1002 static 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
1022 static 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
1056 unlock:
1057         mutex_unlock(&hidg_ida_lock);
1058         return ret;
1059 }
1060
1061 static 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
1075 static 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
1085 static 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
1132 DECLARE_USB_FUNCTION_INIT(hid, hidg_alloc_inst, hidg_alloc);
1133 MODULE_LICENSE("GPL");
1134 MODULE_AUTHOR("Fabien Chouteau");
1135
1136 int 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
1161 void 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 }