drivers/usb/gadget/function/f_accessory.c

   1 /*
   2  * Gadget Function Driver for Android USB accessories
   3  *
   4  * Copyright (C) 2011 Google, Inc.
   5  * Author: Mike Lockwood <lockwood@android.com>
   6  *
   7  * This software is licensed under the terms of the GNU General Public
   8  * License version 2, as published by the Free Software Foundation, and
   9  * may be copied, distributed, and modified under those terms.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  */
  17
  18 /* #define DEBUG */
  19 /* #define VERBOSE_DEBUG */
  20
  21 #include <linux/module.h>
  22 #include <linux/init.h>
  23 #include <linux/poll.h>
  24 #include <linux/delay.h>
  25 #include <linux/wait.h>
  26 #include <linux/err.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/kthread.h>
  29 #include <linux/freezer.h>
  30
  31 #include <linux/types.h>
  32 #include <linux/file.h>
  33 #include <linux/device.h>
  34 #include <linux/miscdevice.h>
  35
  36 #include <linux/hid.h>
  37 #include <linux/hiddev.h>
  38 #include <linux/usb.h>
  39 #include <linux/usb/ch9.h>
  40 #include <linux/usb/f_accessory.h>
  41
  42 #include <linux/configfs.h>
  43 #include <linux/usb/composite.h>
  44
  45 #define MAX_INST_NAME_LEN        40
  46 #define BULK_BUFFER_SIZE    16384
  47 #define ACC_STRING_SIZE     256
  48
  49 #define PROTOCOL_VERSION    2
  50
  51 /* String IDs */
  52 #define INTERFACE_STRING_INDEX  0
  53
  54 /* number of tx and rx requests to allocate */
  55 #define TX_REQ_MAX 4
  56 #define RX_REQ_MAX 2
  57
  58 struct acc_hid_dev {
  59         struct list_head        list;
  60         struct hid_device *hid;
  61         struct acc_dev *dev;
  62         /* accessory defined ID */
  63         int id;
  64         /* HID report descriptor */
  65         u8 *report_desc;
  66         /* length of HID report descriptor */
  67         int report_desc_len;
  68         /* number of bytes of report_desc we have received so far */
  69         int report_desc_offset;
  70 };
  71
  72 struct acc_dev {
  73         struct usb_function function;
  74         struct usb_composite_dev *cdev;
  75         spinlock_t lock;
  76
  77         struct usb_ep *ep_in;
  78         struct usb_ep *ep_out;
  79
  80         /* set to 1 when we connect */
  81         int online:1;
  82         /* Set to 1 when we disconnect.
  83          * Not cleared until our file is closed.
  84          */
  85         int disconnected:1;
  86
  87         /* strings sent by the host */
  88         char manufacturer[ACC_STRING_SIZE];
  89         char model[ACC_STRING_SIZE];
  90         char description[ACC_STRING_SIZE];
  91         char version[ACC_STRING_SIZE];
  92         char uri[ACC_STRING_SIZE];
  93         char serial[ACC_STRING_SIZE];
  94
  95         /* for acc_complete_set_string */
  96         int string_index;
  97
  98         /* set to 1 if we have a pending start request */
  99         int start_requested;
 100
 101         int audio_mode;
 102
 103         /* synchronize access to our device file */
 104         atomic_t open_excl;
 105
 106         struct list_head tx_idle;
 107
 108         wait_queue_head_t read_wq;
 109         wait_queue_head_t write_wq;
 110         struct usb_request *rx_req[RX_REQ_MAX];
 111         int rx_done;
 112
 113         /* delayed work for handling ACCESSORY_START */
 114         struct delayed_work start_work;
 115
 116         /* worker for registering and unregistering hid devices */
 117         struct work_struct hid_work;
 118
 119         /* list of active HID devices */
 120         struct list_head        hid_list;
 121
 122         /* list of new HID devices to register */
 123         struct list_head        new_hid_list;
 124
 125         /* list of dead HID devices to unregister */
 126         struct list_head        dead_hid_list;
 127 };
 128
 129 static struct usb_interface_descriptor acc_interface_desc = {
 130         .bLength                = USB_DT_INTERFACE_SIZE,
 131         .bDescriptorType        = USB_DT_INTERFACE,
 132         .bInterfaceNumber       = 0,
 133         .bNumEndpoints          = 2,
 134         .bInterfaceClass        = USB_CLASS_VENDOR_SPEC,
 135         .bInterfaceSubClass     = USB_SUBCLASS_VENDOR_SPEC,
 136         .bInterfaceProtocol     = 0,
 137 };
 138
 139 static struct usb_endpoint_descriptor acc_highspeed_in_desc = {
 140         .bLength                = USB_DT_ENDPOINT_SIZE,
 141         .bDescriptorType        = USB_DT_ENDPOINT,
 142         .bEndpointAddress       = USB_DIR_IN,
 143         .bmAttributes           = USB_ENDPOINT_XFER_BULK,
 144         .wMaxPacketSize         = __constant_cpu_to_le16(512),
 145 };
 146
 147 static struct usb_endpoint_descriptor acc_highspeed_out_desc = {
 148         .bLength                = USB_DT_ENDPOINT_SIZE,
 149         .bDescriptorType        = USB_DT_ENDPOINT,
 150         .bEndpointAddress       = USB_DIR_OUT,
 151         .bmAttributes           = USB_ENDPOINT_XFER_BULK,
 152         .wMaxPacketSize         = __constant_cpu_to_le16(512),
 153 };
 154
 155 static struct usb_endpoint_descriptor acc_fullspeed_in_desc = {
 156         .bLength                = USB_DT_ENDPOINT_SIZE,
 157         .bDescriptorType        = USB_DT_ENDPOINT,
 158         .bEndpointAddress       = USB_DIR_IN,
 159         .bmAttributes           = USB_ENDPOINT_XFER_BULK,
 160 };
 161
 162 static struct usb_endpoint_descriptor acc_fullspeed_out_desc = {
 163         .bLength                = USB_DT_ENDPOINT_SIZE,
 164         .bDescriptorType        = USB_DT_ENDPOINT,
 165         .bEndpointAddress       = USB_DIR_OUT,
 166         .bmAttributes           = USB_ENDPOINT_XFER_BULK,
 167 };
 168
 169 static struct usb_descriptor_header *fs_acc_descs[] = {
 170         (struct usb_descriptor_header *) &acc_interface_desc,
 171         (struct usb_descriptor_header *) &acc_fullspeed_in_desc,
 172         (struct usb_descriptor_header *) &acc_fullspeed_out_desc,
 173         NULL,
 174 };
 175
 176 static struct usb_descriptor_header *hs_acc_descs[] = {
 177         (struct usb_descriptor_header *) &acc_interface_desc,
 178         (struct usb_descriptor_header *) &acc_highspeed_in_desc,
 179         (struct usb_descriptor_header *) &acc_highspeed_out_desc,
 180         NULL,
 181 };
 182
 183 static struct usb_string acc_string_defs[] = {
 184         [INTERFACE_STRING_INDEX].s      = "Android Accessory Interface",
 185         {  },   /* end of list */
 186 };
 187
 188 static struct usb_gadget_strings acc_string_table = {
 189         .language               = 0x0409,       /* en-US */
 190         .strings                = acc_string_defs,
 191 };
 192
 193 static struct usb_gadget_strings *acc_strings[] = {
 194         &acc_string_table,
 195         NULL,
 196 };
 197
 198 /* temporary variable used between acc_open() and acc_gadget_bind() */
 199 static struct acc_dev *_acc_dev;
 200
 201 struct acc_instance {
 202         struct usb_function_instance func_inst;
 203         const char *name;
 204 };
 205
 206 static inline struct acc_dev *func_to_dev(struct usb_function *f)
 207 {
 208         return container_of(f, struct acc_dev, function);
 209 }
 210
 211 static struct usb_request *acc_request_new(struct usb_ep *ep, int buffer_size)
 212 {
 213         struct usb_request *req = usb_ep_alloc_request(ep, GFP_KERNEL);
 214         if (!req)
 215                 return NULL;
 216
 217         /* now allocate buffers for the requests */
 218         req->buf = kmalloc(buffer_size, GFP_KERNEL);
 219         if (!req->buf) {
 220                 usb_ep_free_request(ep, req);
 221                 return NULL;
 222         }
 223
 224         return req;
 225 }
 226
 227 static void acc_request_free(struct usb_request *req, struct usb_ep *ep)
 228 {
 229         if (req) {
 230                 kfree(req->buf);
 231                 usb_ep_free_request(ep, req);
 232         }
 233 }
 234
 235 /* add a request to the tail of a list */
 236 static void req_put(struct acc_dev *dev, struct list_head *head,
 237                 struct usb_request *req)
 238 {
 239         unsigned long flags;
 240
 241         spin_lock_irqsave(&dev->lock, flags);
 242         list_add_tail(&req->list, head);
 243         spin_unlock_irqrestore(&dev->lock, flags);
 244 }
 245
 246 /* remove a request from the head of a list */
 247 static struct usb_request *req_get(struct acc_dev *dev, struct list_head *head)
 248 {
 249         unsigned long flags;
 250         struct usb_request *req;
 251
 252         spin_lock_irqsave(&dev->lock, flags);
 253         if (list_empty(head)) {
 254                 req = 0;
 255         } else {
 256                 req = list_first_entry(head, struct usb_request, list);
 257                 list_del(&req->list);
 258         }
 259         spin_unlock_irqrestore(&dev->lock, flags);
 260         return req;
 261 }
 262
 263 static void acc_set_disconnected(struct acc_dev *dev)
 264 {
 265         dev->online = 0;
 266         dev->disconnected = 1;
 267 }
 268
 269 static void acc_complete_in(struct usb_ep *ep, struct usb_request *req)
 270 {
 271         struct acc_dev *dev = _acc_dev;
 272
 273         if (req->status == -ESHUTDOWN) {
 274                 pr_debug("acc_complete_in set disconnected");
 275                 acc_set_disconnected(dev);
 276         }
 277
 278         req_put(dev, &dev->tx_idle, req);
 279
 280         wake_up(&dev->write_wq);
 281 }
 282
 283 static void acc_complete_out(struct usb_ep *ep, struct usb_request *req)
 284 {
 285         struct acc_dev *dev = _acc_dev;
 286
 287         dev->rx_done = 1;
 288         if (req->status == -ESHUTDOWN) {
 289                 pr_debug("acc_complete_out set disconnected");
 290                 acc_set_disconnected(dev);
 291         }
 292
 293         wake_up(&dev->read_wq);
 294 }
 295
 296 static void acc_complete_set_string(struct usb_ep *ep, struct usb_request *req)
 297 {
 298         struct acc_dev  *dev = ep->driver_data;
 299         char *string_dest = NULL;
 300         int length = req->actual;
 301
 302         if (req->status != 0) {
 303                 pr_err("acc_complete_set_string, err %d\n", req->status);
 304                 return;
 305         }
 306
 307         switch (dev->string_index) {
 308         case ACCESSORY_STRING_MANUFACTURER:
 309                 string_dest = dev->manufacturer;
 310                 break;
 311         case ACCESSORY_STRING_MODEL:
 312                 string_dest = dev->model;
 313                 break;
 314         case ACCESSORY_STRING_DESCRIPTION:
 315                 string_dest = dev->description;
 316                 break;
 317         case ACCESSORY_STRING_VERSION:
 318                 string_dest = dev->version;
 319                 break;
 320         case ACCESSORY_STRING_URI:
 321                 string_dest = dev->uri;
 322                 break;
 323         case ACCESSORY_STRING_SERIAL:
 324                 string_dest = dev->serial;
 325                 break;
 326         }
 327         if (string_dest) {
 328                 unsigned long flags;
 329
 330                 if (length >= ACC_STRING_SIZE)
 331                         length = ACC_STRING_SIZE - 1;
 332
 333                 spin_lock_irqsave(&dev->lock, flags);
 334                 memcpy(string_dest, req->buf, length);
 335                 /* ensure zero termination */
 336                 string_dest[length] = 0;
 337                 spin_unlock_irqrestore(&dev->lock, flags);
 338         } else {
 339                 pr_err("unknown accessory string index %d\n",
 340                         dev->string_index);
 341         }
 342 }
 343
 344 static void acc_complete_set_hid_report_desc(struct usb_ep *ep,
 345                 struct usb_request *req)
 346 {
 347         struct acc_hid_dev *hid = req->context;
 348         struct acc_dev *dev = hid->dev;
 349         int length = req->actual;
 350
 351         if (req->status != 0) {
 352                 pr_err("acc_complete_set_hid_report_desc, err %d\n",
 353                         req->status);
 354                 return;
 355         }
 356
 357         memcpy(hid->report_desc + hid->report_desc_offset, req->buf, length);
 358         hid->report_desc_offset += length;
 359         if (hid->report_desc_offset == hid->report_desc_len) {
 360                 /* After we have received the entire report descriptor
 361                  * we schedule work to initialize the HID device
 362                  */
 363                 schedule_work(&dev->hid_work);
 364         }
 365 }
 366
 367 static void acc_complete_send_hid_event(struct usb_ep *ep,
 368                 struct usb_request *req)
 369 {
 370         struct acc_hid_dev *hid = req->context;
 371         int length = req->actual;
 372
 373         if (req->status != 0) {
 374                 pr_err("acc_complete_send_hid_event, err %d\n", req->status);
 375                 return;
 376         }
 377
 378         hid_report_raw_event(hid->hid, HID_INPUT_REPORT, req->buf, length, 1);
 379 }
 380
 381 static int acc_hid_parse(struct hid_device *hid)
 382 {
 383         struct acc_hid_dev *hdev = hid->driver_data;
 384
 385         hid_parse_report(hid, hdev->report_desc, hdev->report_desc_len);
 386         return 0;
 387 }
 388
 389 static int acc_hid_start(struct hid_device *hid)
 390 {
 391         return 0;
 392 }
 393
 394 static void acc_hid_stop(struct hid_device *hid)
 395 {
 396 }
 397
 398 static int acc_hid_open(struct hid_device *hid)
 399 {
 400         return 0;
 401 }
 402
 403 static void acc_hid_close(struct hid_device *hid)
 404 {
 405 }
 406
 407 static int acc_hid_raw_request(struct hid_device *hid, unsigned char reportnum,
 408         __u8 *buf, size_t len, unsigned char rtype, int reqtype)
 409 {
 410         return 0;
 411 }
 412
 413 static struct hid_ll_driver acc_hid_ll_driver = {
 414         .parse = acc_hid_parse,
 415         .start = acc_hid_start,
 416         .stop = acc_hid_stop,
 417         .open = acc_hid_open,
 418         .close = acc_hid_close,
 419         .raw_request = acc_hid_raw_request,
 420 };
 421
 422 static struct acc_hid_dev *acc_hid_new(struct acc_dev *dev,
 423                 int id, int desc_len)
 424 {
 425         struct acc_hid_dev *hdev;
 426
 427         hdev = kzalloc(sizeof(*hdev), GFP_ATOMIC);
 428         if (!hdev)
 429                 return NULL;
 430         hdev->report_desc = kzalloc(desc_len, GFP_ATOMIC);
 431         if (!hdev->report_desc) {
 432                 kfree(hdev);
 433                 return NULL;
 434         }
 435         hdev->dev = dev;
 436         hdev->id = id;
 437         hdev->report_desc_len = desc_len;
 438
 439         return hdev;
 440 }
 441
 442 static struct acc_hid_dev *acc_hid_get(struct list_head *list, int id)
 443 {
 444         struct acc_hid_dev *hid;
 445
 446         list_for_each_entry(hid, list, list) {
 447                 if (hid->id == id)
 448                         return hid;
 449         }
 450         return NULL;
 451 }
 452
 453 static int acc_register_hid(struct acc_dev *dev, int id, int desc_length)
 454 {
 455         struct acc_hid_dev *hid;
 456         unsigned long flags;
 457
 458         /* report descriptor length must be > 0 */
 459         if (desc_length <= 0)
 460                 return -EINVAL;
 461
 462         spin_lock_irqsave(&dev->lock, flags);
 463         /* replace HID if one already exists with this ID */
 464         hid = acc_hid_get(&dev->hid_list, id);
 465         if (!hid)
 466                 hid = acc_hid_get(&dev->new_hid_list, id);
 467         if (hid)
 468                 list_move(&hid->list, &dev->dead_hid_list);
 469
 470         hid = acc_hid_new(dev, id, desc_length);
 471         if (!hid) {
 472                 spin_unlock_irqrestore(&dev->lock, flags);
 473                 return -ENOMEM;
 474         }
 475
 476         list_add(&hid->list, &dev->new_hid_list);
 477         spin_unlock_irqrestore(&dev->lock, flags);
 478
 479         /* schedule work to register the HID device */
 480         schedule_work(&dev->hid_work);
 481         return 0;
 482 }
 483
 484 static int acc_unregister_hid(struct acc_dev *dev, int id)
 485 {
 486         struct acc_hid_dev *hid;
 487         unsigned long flags;
 488
 489         spin_lock_irqsave(&dev->lock, flags);
 490         hid = acc_hid_get(&dev->hid_list, id);
 491         if (!hid)
 492                 hid = acc_hid_get(&dev->new_hid_list, id);
 493         if (!hid) {
 494                 spin_unlock_irqrestore(&dev->lock, flags);
 495                 return -EINVAL;
 496         }
 497
 498         list_move(&hid->list, &dev->dead_hid_list);
 499         spin_unlock_irqrestore(&dev->lock, flags);
 500
 501         schedule_work(&dev->hid_work);
 502         return 0;
 503 }
 504
 505 static int create_bulk_endpoints(struct acc_dev *dev,
 506                                 struct usb_endpoint_descriptor *in_desc,
 507                                 struct usb_endpoint_descriptor *out_desc)
 508 {
 509         struct usb_composite_dev *cdev = dev->cdev;
 510         struct usb_request *req;
 511         struct usb_ep *ep;
 512         int i;
 513
 514         DBG(cdev, "create_bulk_endpoints dev: %p\n", dev);
 515
 516         ep = usb_ep_autoconfig(cdev->gadget, in_desc);
 517         if (!ep) {
 518                 DBG(cdev, "usb_ep_autoconfig for ep_in failed\n");
 519                 return -ENODEV;
 520         }
 521         DBG(cdev, "usb_ep_autoconfig for ep_in got %s\n", ep->name);
 522         ep->driver_data = dev;          /* claim the endpoint */
 523         dev->ep_in = ep;
 524
 525         ep = usb_ep_autoconfig(cdev->gadget, out_desc);
 526         if (!ep) {
 527                 DBG(cdev, "usb_ep_autoconfig for ep_out failed\n");
 528                 return -ENODEV;
 529         }
 530         DBG(cdev, "usb_ep_autoconfig for ep_out got %s\n", ep->name);
 531         ep->driver_data = dev;          /* claim the endpoint */
 532         dev->ep_out = ep;
 533
 534         /* now allocate requests for our endpoints */
 535         for (i = 0; i < TX_REQ_MAX; i++) {
 536                 req = acc_request_new(dev->ep_in, BULK_BUFFER_SIZE);
 537                 if (!req)
 538                         goto fail;
 539                 req->complete = acc_complete_in;
 540                 req_put(dev, &dev->tx_idle, req);
 541         }
 542         for (i = 0; i < RX_REQ_MAX; i++) {
 543                 req = acc_request_new(dev->ep_out, BULK_BUFFER_SIZE);
 544                 if (!req)
 545                         goto fail;
 546                 req->complete = acc_complete_out;
 547                 dev->rx_req[i] = req;
 548         }
 549
 550         return 0;
 551
 552 fail:
 553         pr_err("acc_bind() could not allocate requests\n");
 554         while ((req = req_get(dev, &dev->tx_idle)))
 555                 acc_request_free(req, dev->ep_in);
 556         for (i = 0; i < RX_REQ_MAX; i++)
 557                 acc_request_free(dev->rx_req[i], dev->ep_out);
 558         return -1;
 559 }
 560
 561 static ssize_t acc_read(struct file *fp, char __user *buf,
 562         size_t count, loff_t *pos)
 563 {
 564         struct acc_dev *dev = fp->private_data;
 565         struct usb_request *req;
 566         ssize_t r = count;
 567         unsigned xfer;
 568         int ret = 0;
 569
 570         pr_debug("acc_read(%zu)\n", count);
 571
 572         if (dev->disconnected) {
 573                 pr_debug("acc_read disconnected");
 574                 return -ENODEV;
 575         }
 576
 577         if (count > BULK_BUFFER_SIZE)
 578                 count = BULK_BUFFER_SIZE;
 579
 580         /* we will block until we're online */
 581         pr_debug("acc_read: waiting for online\n");
 582         ret = wait_event_interruptible(dev->read_wq, dev->online);
 583         if (ret < 0) {
 584                 r = ret;
 585                 goto done;
 586         }
 587
 588         if (dev->rx_done) {
 589                 // last req cancelled. try to get it.
 590                 req = dev->rx_req[0];
 591                 goto copy_data;
 592         }
 593
 594 requeue_req:
 595         /* queue a request */
 596         req = dev->rx_req[0];
 597         req->length = count;
 598         dev->rx_done = 0;
 599         ret = usb_ep_queue(dev->ep_out, req, GFP_KERNEL);
 600         if (ret < 0) {
 601                 r = -EIO;
 602                 goto done;
 603         } else {
 604                 pr_debug("rx %p queue\n", req);
 605         }
 606
 607         /* wait for a request to complete */
 608         ret = wait_event_interruptible(dev->read_wq, dev->rx_done);
 609         if (ret < 0) {
 610                 r = ret;
 611                 ret = usb_ep_dequeue(dev->ep_out, req);
 612                 if (ret != 0) {
 613                         // cancel failed. There can be a data already received.
 614                         // it will be retrieved in the next read.
 615                         pr_debug("acc_read: cancelling failed %d", ret);
 616                 }
 617                 goto done;
 618         }
 619
 620 copy_data:
 621         dev->rx_done = 0;
 622         if (dev->online) {
 623                 /* If we got a 0-len packet, throw it back and try again. */
 624                 if (req->actual == 0)
 625                         goto requeue_req;
 626
 627                 pr_debug("rx %p %u\n", req, req->actual);
 628                 xfer = (req->actual < count) ? req->actual : count;
 629                 r = xfer;
 630                 if (copy_to_user(buf, req->buf, xfer))
 631                         r = -EFAULT;
 632         } else
 633                 r = -EIO;
 634
 635 done:
 636         pr_debug("acc_read returning %zd\n", r);
 637         return r;
 638 }
 639
 640 static ssize_t acc_write(struct file *fp, const char __user *buf,
 641         size_t count, loff_t *pos)
 642 {
 643         struct acc_dev *dev = fp->private_data;
 644         struct usb_request *req = 0;
 645         ssize_t r = count;
 646         unsigned xfer;
 647         int ret;
 648
 649         pr_debug("acc_write(%zu)\n", count);
 650
 651         if (!dev->online || dev->disconnected) {
 652                 pr_debug("acc_write disconnected or not online");
 653                 return -ENODEV;
 654         }
 655
 656         while (count > 0) {
 657                 if (!dev->online) {
 658                         pr_debug("acc_write dev->error\n");
 659                         r = -EIO;
 660                         break;
 661                 }
 662
 663                 /* get an idle tx request to use */
 664                 req = 0;
 665                 ret = wait_event_interruptible(dev->write_wq,
 666                         ((req = req_get(dev, &dev->tx_idle)) || !dev->online));
 667                 if (!req) {
 668                         r = ret;
 669                         break;
 670                 }
 671
 672                 if (count > BULK_BUFFER_SIZE) {
 673                         xfer = BULK_BUFFER_SIZE;
 674                         /* ZLP, They will be more TX requests so not yet. */
 675                         req->zero = 0;
 676                 } else {
 677                         xfer = count;
 678                         /* If the data length is a multple of the
 679                          * maxpacket size then send a zero length packet(ZLP).
 680                         */
 681                         req->zero = ((xfer % dev->ep_in->maxpacket) == 0);
 682                 }
 683                 if (copy_from_user(req->buf, buf, xfer)) {
 684                         r = -EFAULT;
 685                         break;
 686                 }
 687
 688                 req->length = xfer;
 689                 ret = usb_ep_queue(dev->ep_in, req, GFP_KERNEL);
 690                 if (ret < 0) {
 691                         pr_debug("acc_write: xfer error %d\n", ret);
 692                         r = -EIO;
 693                         break;
 694                 }
 695
 696                 buf += xfer;
 697                 count -= xfer;
 698
 699                 /* zero this so we don't try to free it on error exit */
 700                 req = 0;
 701         }
 702
 703         if (req)
 704                 req_put(dev, &dev->tx_idle, req);
 705
 706         pr_debug("acc_write returning %zd\n", r);
 707         return r;
 708 }
 709
 710 static long acc_ioctl(struct file *fp, unsigned code, unsigned long value)
 711 {
 712         struct acc_dev *dev = fp->private_data;
 713         char *src = NULL;
 714         int ret;
 715
 716         switch (code) {
 717         case ACCESSORY_GET_STRING_MANUFACTURER:
 718                 src = dev->manufacturer;
 719                 break;
 720         case ACCESSORY_GET_STRING_MODEL:
 721                 src = dev->model;
 722                 break;
 723         case ACCESSORY_GET_STRING_DESCRIPTION:
 724                 src = dev->description;
 725                 break;
 726         case ACCESSORY_GET_STRING_VERSION:
 727                 src = dev->version;
 728                 break;
 729         case ACCESSORY_GET_STRING_URI:
 730                 src = dev->uri;
 731                 break;
 732         case ACCESSORY_GET_STRING_SERIAL:
 733                 src = dev->serial;
 734                 break;
 735         case ACCESSORY_IS_START_REQUESTED:
 736                 return dev->start_requested;
 737         case ACCESSORY_GET_AUDIO_MODE:
 738                 return dev->audio_mode;
 739         }
 740         if (!src)
 741                 return -EINVAL;
 742
 743         ret = strlen(src) + 1;
 744         if (copy_to_user((void __user *)value, src, ret))
 745                 ret = -EFAULT;
 746         return ret;
 747 }
 748
 749 static int acc_open(struct inode *ip, struct file *fp)
 750 {
 751         printk(KERN_INFO "acc_open\n");
 752         if (atomic_xchg(&_acc_dev->open_excl, 1))
 753                 return -EBUSY;
 754
 755         _acc_dev->disconnected = 0;
 756         fp->private_data = _acc_dev;
 757         return 0;
 758 }
 759
 760 static int acc_release(struct inode *ip, struct file *fp)
 761 {
 762         printk(KERN_INFO "acc_release\n");
 763
 764         WARN_ON(!atomic_xchg(&_acc_dev->open_excl, 0));
 765         _acc_dev->disconnected = 0;
 766         return 0;
 767 }
 768
 769 /* file operations for /dev/usb_accessory */
 770 static const struct file_operations acc_fops = {
 771         .owner = THIS_MODULE,
 772         .read = acc_read,
 773         .write = acc_write,
 774         .unlocked_ioctl = acc_ioctl,
 775         .open = acc_open,
 776         .release = acc_release,
 777 };
 778
 779 static int acc_hid_probe(struct hid_device *hdev,
 780                 const struct hid_device_id *id)
 781 {
 782         int ret;
 783
 784         ret = hid_parse(hdev);
 785         if (ret)
 786                 return ret;
 787         return hid_hw_start(hdev, HID_CONNECT_DEFAULT);
 788 }
 789
 790 static struct miscdevice acc_device = {
 791         .minor = MISC_DYNAMIC_MINOR,
 792         .name = "usb_accessory",
 793         .fops = &acc_fops,
 794 };
 795
 796 static const struct hid_device_id acc_hid_table[] = {
 797         { HID_USB_DEVICE(HID_ANY_ID, HID_ANY_ID) },
 798         { }
 799 };
 800
 801 static struct hid_driver acc_hid_driver = {
 802         .name = "USB accessory",
 803         .id_table = acc_hid_table,
 804         .probe = acc_hid_probe,
 805 };
 806
 807 int acc_ctrlrequest(struct usb_composite_dev *cdev,
 808                                 const struct usb_ctrlrequest *ctrl)
 809 {
 810         struct acc_dev  *dev = _acc_dev;
 811         int     value = -EOPNOTSUPP;
 812         struct acc_hid_dev *hid;
 813         int offset;
 814         u8 b_requestType = ctrl->bRequestType;
 815         u8 b_request = ctrl->bRequest;
 816         u16     w_index = le16_to_cpu(ctrl->wIndex);
 817         u16     w_value = le16_to_cpu(ctrl->wValue);
 818         u16     w_length = le16_to_cpu(ctrl->wLength);
 819         unsigned long flags;
 820
 821 /*
 822         printk(KERN_INFO "acc_ctrlrequest "
 823                         "%02x.%02x v%04x i%04x l%u\n",
 824                         b_requestType, b_request,
 825                         w_value, w_index, w_length);
 826 */
 827
 828         if (b_requestType == (USB_DIR_OUT | USB_TYPE_VENDOR)) {
 829                 if (b_request == ACCESSORY_START) {
 830                         dev->start_requested = 1;
 831                         schedule_delayed_work(
 832                                 &dev->start_work, msecs_to_jiffies(10));
 833                         value = 0;
 834                 } else if (b_request == ACCESSORY_SEND_STRING) {
 835                         dev->string_index = w_index;
 836                         cdev->gadget->ep0->driver_data = dev;
 837                         cdev->req->complete = acc_complete_set_string;
 838                         value = w_length;
 839                 } else if (b_request == ACCESSORY_SET_AUDIO_MODE &&
 840                                 w_index == 0 && w_length == 0) {
 841                         dev->audio_mode = w_value;
 842                         value = 0;
 843                 } else if (b_request == ACCESSORY_REGISTER_HID) {
 844                         value = acc_register_hid(dev, w_value, w_index);
 845                 } else if (b_request == ACCESSORY_UNREGISTER_HID) {
 846                         value = acc_unregister_hid(dev, w_value);
 847                 } else if (b_request == ACCESSORY_SET_HID_REPORT_DESC) {
 848                         spin_lock_irqsave(&dev->lock, flags);
 849                         hid = acc_hid_get(&dev->new_hid_list, w_value);
 850                         spin_unlock_irqrestore(&dev->lock, flags);
 851                         if (!hid) {
 852                                 value = -EINVAL;
 853                                 goto err;
 854                         }
 855                         offset = w_index;
 856                         if (offset != hid->report_desc_offset
 857                                 || offset + w_length > hid->report_desc_len) {
 858                                 value = -EINVAL;
 859                                 goto err;
 860                         }
 861                         cdev->req->context = hid;
 862                         cdev->req->complete = acc_complete_set_hid_report_desc;
 863                         value = w_length;
 864                 } else if (b_request == ACCESSORY_SEND_HID_EVENT) {
 865                         spin_lock_irqsave(&dev->lock, flags);
 866                         hid = acc_hid_get(&dev->hid_list, w_value);
 867                         spin_unlock_irqrestore(&dev->lock, flags);
 868                         if (!hid) {
 869                                 value = -EINVAL;
 870                                 goto err;
 871                         }
 872                         cdev->req->context = hid;
 873                         cdev->req->complete = acc_complete_send_hid_event;
 874                         value = w_length;
 875                 }
 876         } else if (b_requestType == (USB_DIR_IN | USB_TYPE_VENDOR)) {
 877                 if (b_request == ACCESSORY_GET_PROTOCOL) {
 878                         *((u16 *)cdev->req->buf) = PROTOCOL_VERSION;
 879                         value = sizeof(u16);
 880
 881                         /* clear any string left over from a previous session */
 882                         memset(dev->manufacturer, 0, sizeof(dev->manufacturer));
 883                         memset(dev->model, 0, sizeof(dev->model));
 884                         memset(dev->description, 0, sizeof(dev->description));
 885                         memset(dev->version, 0, sizeof(dev->version));
 886                         memset(dev->uri, 0, sizeof(dev->uri));
 887                         memset(dev->serial, 0, sizeof(dev->serial));
 888                         dev->start_requested = 0;
 889                         dev->audio_mode = 0;
 890                 }
 891         }
 892
 893         if (value >= 0) {
 894                 cdev->req->zero = 0;
 895                 cdev->req->length = value;
 896                 value = usb_ep_queue(cdev->gadget->ep0, cdev->req, GFP_ATOMIC);
 897                 if (value < 0)
 898                         ERROR(cdev, "%s setup response queue error\n",
 899                                 __func__);
 900         }
 901
 902 err:
 903         if (value == -EOPNOTSUPP)
 904                 VDBG(cdev,
 905                         "unknown class-specific control req "
 906                         "%02x.%02x v%04x i%04x l%u\n",
 907                         ctrl->bRequestType, ctrl->bRequest,
 908                         w_value, w_index, w_length);
 909         return value;
 910 }
 911 EXPORT_SYMBOL_GPL(acc_ctrlrequest);
 912
 913 static int
 914 __acc_function_bind(struct usb_configuration *c,
 915                         struct usb_function *f, bool configfs)
 916 {
 917         struct usb_composite_dev *cdev = c->cdev;
 918         struct acc_dev  *dev = func_to_dev(f);
 919         int                     id;
 920         int                     ret;
 921
 922         DBG(cdev, "acc_function_bind dev: %p\n", dev);
 923
 924         if (configfs) {
 925                 if (acc_string_defs[INTERFACE_STRING_INDEX].id == 0) {
 926                         ret = usb_string_id(c->cdev);
 927                         if (ret < 0)
 928                                 return ret;
 929                         acc_string_defs[INTERFACE_STRING_INDEX].id = ret;
 930                         acc_interface_desc.iInterface = ret;
 931                 }
 932                 dev->cdev = c->cdev;
 933         }
 934         ret = hid_register_driver(&acc_hid_driver);
 935         if (ret)
 936                 return ret;
 937
 938         dev->start_requested = 0;
 939
 940         /* allocate interface ID(s) */
 941         id = usb_interface_id(c, f);
 942         if (id < 0)
 943                 return id;
 944         acc_interface_desc.bInterfaceNumber = id;
 945
 946         /* allocate endpoints */
 947         ret = create_bulk_endpoints(dev, &acc_fullspeed_in_desc,
 948                         &acc_fullspeed_out_desc);
 949         if (ret)
 950                 return ret;
 951
 952         /* support high speed hardware */
 953         if (gadget_is_dualspeed(c->cdev->gadget)) {
 954                 acc_highspeed_in_desc.bEndpointAddress =
 955                         acc_fullspeed_in_desc.bEndpointAddress;
 956                 acc_highspeed_out_desc.bEndpointAddress =
 957                         acc_fullspeed_out_desc.bEndpointAddress;
 958         }
 959
 960         DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n",
 961                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 962                         f->name, dev->ep_in->name, dev->ep_out->name);
 963         return 0;
 964 }
 965
 966 static int
 967 acc_function_bind_configfs(struct usb_configuration *c,
 968                         struct usb_function *f) {
 969         return __acc_function_bind(c, f, true);
 970 }
 971
 972 static void
 973 kill_all_hid_devices(struct acc_dev *dev)
 974 {
 975         struct acc_hid_dev *hid;
 976         struct list_head *entry, *temp;
 977         unsigned long flags;
 978
 979         /* do nothing if usb accessory device doesn't exist */
 980         if (!dev)
 981                 return;
 982
 983         spin_lock_irqsave(&dev->lock, flags);
 984         list_for_each_safe(entry, temp, &dev->hid_list) {
 985                 hid = list_entry(entry, struct acc_hid_dev, list);
 986                 list_del(&hid->list);
 987                 list_add(&hid->list, &dev->dead_hid_list);
 988         }
 989         list_for_each_safe(entry, temp, &dev->new_hid_list) {
 990                 hid = list_entry(entry, struct acc_hid_dev, list);
 991                 list_del(&hid->list);
 992                 list_add(&hid->list, &dev->dead_hid_list);
 993         }
 994         spin_unlock_irqrestore(&dev->lock, flags);
 995
 996         schedule_work(&dev->hid_work);
 997 }
 998
 999 static void
1000 acc_hid_unbind(struct acc_dev *dev)
1001 {
1002         hid_unregister_driver(&acc_hid_driver);
1003         kill_all_hid_devices(dev);
1004 }
1005
1006 static void
1007 acc_function_unbind(struct usb_configuration *c, struct usb_function *f)
1008 {
1009         struct acc_dev  *dev = func_to_dev(f);
1010         struct usb_request *req;
1011         int i;
1012
1013         while ((req = req_get(dev, &dev->tx_idle)))
1014                 acc_request_free(req, dev->ep_in);
1015         for (i = 0; i < RX_REQ_MAX; i++)
1016                 acc_request_free(dev->rx_req[i], dev->ep_out);
1017
1018         acc_hid_unbind(dev);
1019 }
1020
1021 static void acc_start_work(struct work_struct *data)
1022 {
1023         char *envp[2] = { "ACCESSORY=START", NULL };
1024         kobject_uevent_env(&acc_device.this_device->kobj, KOBJ_CHANGE, envp);
1025 }
1026
1027 static int acc_hid_init(struct acc_hid_dev *hdev)
1028 {
1029         struct hid_device *hid;
1030         int ret;
1031
1032         hid = hid_allocate_device();
1033         if (IS_ERR(hid))
1034                 return PTR_ERR(hid);
1035
1036         hid->ll_driver = &acc_hid_ll_driver;
1037         hid->dev.parent = acc_device.this_device;
1038
1039         hid->bus = BUS_USB;
1040         hid->vendor = HID_ANY_ID;
1041         hid->product = HID_ANY_ID;
1042         hid->driver_data = hdev;
1043         ret = hid_add_device(hid);
1044         if (ret) {
1045                 pr_err("can't add hid device: %d\n", ret);
1046                 hid_destroy_device(hid);
1047                 return ret;
1048         }
1049
1050         hdev->hid = hid;
1051         return 0;
1052 }
1053
1054 static void acc_hid_delete(struct acc_hid_dev *hid)
1055 {
1056         kfree(hid->report_desc);
1057         kfree(hid);
1058 }
1059
1060 static void acc_hid_work(struct work_struct *data)
1061 {
1062         struct acc_dev *dev = _acc_dev;
1063         struct list_head        *entry, *temp;
1064         struct acc_hid_dev *hid;
1065         struct list_head        new_list, dead_list;
1066         unsigned long flags;
1067
1068         INIT_LIST_HEAD(&new_list);
1069
1070         spin_lock_irqsave(&dev->lock, flags);
1071
1072         /* copy hids that are ready for initialization to new_list */
1073         list_for_each_safe(entry, temp, &dev->new_hid_list) {
1074                 hid = list_entry(entry, struct acc_hid_dev, list);
1075                 if (hid->report_desc_offset == hid->report_desc_len)
1076                         list_move(&hid->list, &new_list);
1077         }
1078
1079         if (list_empty(&dev->dead_hid_list)) {
1080                 INIT_LIST_HEAD(&dead_list);
1081         } else {
1082                 /* move all of dev->dead_hid_list to dead_list */
1083                 dead_list.prev = dev->dead_hid_list.prev;
1084                 dead_list.next = dev->dead_hid_list.next;
1085                 dead_list.next->prev = &dead_list;
1086                 dead_list.prev->next = &dead_list;
1087                 INIT_LIST_HEAD(&dev->dead_hid_list);
1088         }
1089
1090         spin_unlock_irqrestore(&dev->lock, flags);
1091
1092         /* register new HID devices */
1093         list_for_each_safe(entry, temp, &new_list) {
1094                 hid = list_entry(entry, struct acc_hid_dev, list);
1095                 if (acc_hid_init(hid)) {
1096                         pr_err("can't add HID device %p\n", hid);
1097                         acc_hid_delete(hid);
1098                 } else {
1099                         spin_lock_irqsave(&dev->lock, flags);
1100                         list_move(&hid->list, &dev->hid_list);
1101                         spin_unlock_irqrestore(&dev->lock, flags);
1102                 }
1103         }
1104
1105         /* remove dead HID devices */
1106         list_for_each_safe(entry, temp, &dead_list) {
1107                 hid = list_entry(entry, struct acc_hid_dev, list);
1108                 list_del(&hid->list);
1109                 if (hid->hid)
1110                         hid_destroy_device(hid->hid);
1111                 acc_hid_delete(hid);
1112         }
1113 }
1114
1115 static int acc_function_set_alt(struct usb_function *f,
1116                 unsigned intf, unsigned alt)
1117 {
1118         struct acc_dev  *dev = func_to_dev(f);
1119         struct usb_composite_dev *cdev = f->config->cdev;
1120         int ret;
1121
1122         DBG(cdev, "acc_function_set_alt intf: %d alt: %d\n", intf, alt);
1123
1124         ret = config_ep_by_speed(cdev->gadget, f, dev->ep_in);
1125         if (ret)
1126                 return ret;
1127
1128         ret = usb_ep_enable(dev->ep_in);
1129         if (ret)
1130                 return ret;
1131
1132         ret = config_ep_by_speed(cdev->gadget, f, dev->ep_out);
1133         if (ret)
1134                 return ret;
1135
1136         ret = usb_ep_enable(dev->ep_out);
1137         if (ret) {
1138                 usb_ep_disable(dev->ep_in);
1139                 return ret;
1140         }
1141
1142         dev->online = 1;
1143
1144         /* readers may be blocked waiting for us to go online */
1145         wake_up(&dev->read_wq);
1146         return 0;
1147 }
1148
1149 static void acc_function_disable(struct usb_function *f)
1150 {
1151         struct acc_dev  *dev = func_to_dev(f);
1152         struct usb_composite_dev        *cdev = dev->cdev;
1153
1154         DBG(cdev, "acc_function_disable\n");
1155         acc_set_disconnected(dev);
1156         usb_ep_disable(dev->ep_in);
1157         usb_ep_disable(dev->ep_out);
1158
1159         /* readers may be blocked waiting for us to go online */
1160         wake_up(&dev->read_wq);
1161
1162         VDBG(cdev, "%s disabled\n", dev->function.name);
1163 }
1164
1165 static int acc_setup(void)
1166 {
1167         struct acc_dev *dev;
1168         int ret;
1169
1170         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1171         if (!dev)
1172                 return -ENOMEM;
1173
1174         spin_lock_init(&dev->lock);
1175         init_waitqueue_head(&dev->read_wq);
1176         init_waitqueue_head(&dev->write_wq);
1177         atomic_set(&dev->open_excl, 0);
1178         INIT_LIST_HEAD(&dev->tx_idle);
1179         INIT_LIST_HEAD(&dev->hid_list);
1180         INIT_LIST_HEAD(&dev->new_hid_list);
1181         INIT_LIST_HEAD(&dev->dead_hid_list);
1182         INIT_DELAYED_WORK(&dev->start_work, acc_start_work);
1183         INIT_WORK(&dev->hid_work, acc_hid_work);
1184
1185         /* _acc_dev must be set before calling usb_gadget_register_driver */
1186         _acc_dev = dev;
1187
1188         ret = misc_register(&acc_device);
1189         if (ret)
1190                 goto err;
1191
1192         return 0;
1193
1194 err:
1195         kfree(dev);
1196         pr_err("USB accessory gadget driver failed to initialize\n");
1197         return ret;
1198 }
1199
1200 void acc_disconnect(void)
1201 {
1202         /* unregister all HID devices if USB is disconnected */
1203         kill_all_hid_devices(_acc_dev);
1204 }
1205 EXPORT_SYMBOL_GPL(acc_disconnect);
1206
1207 static void acc_cleanup(void)
1208 {
1209         misc_deregister(&acc_device);
1210         kfree(_acc_dev);
1211         _acc_dev = NULL;
1212 }
1213 static struct acc_instance *to_acc_instance(struct config_item *item)
1214 {
1215         return container_of(to_config_group(item), struct acc_instance,
1216                 func_inst.group);
1217 }
1218
1219 static void acc_attr_release(struct config_item *item)
1220 {
1221         struct acc_instance *fi_acc = to_acc_instance(item);
1222
1223         usb_put_function_instance(&fi_acc->func_inst);
1224 }
1225
1226 static struct configfs_item_operations acc_item_ops = {
1227         .release        = acc_attr_release,
1228 };
1229
1230 static struct config_item_type acc_func_type = {
1231         .ct_item_ops    = &acc_item_ops,
1232         .ct_owner       = THIS_MODULE,
1233 };
1234
1235 static struct acc_instance *to_fi_acc(struct usb_function_instance *fi)
1236 {
1237         return container_of(fi, struct acc_instance, func_inst);
1238 }
1239
1240 static int acc_set_inst_name(struct usb_function_instance *fi, const char *name)
1241 {
1242         struct acc_instance *fi_acc;
1243         char *ptr;
1244         int name_len;
1245
1246         name_len = strlen(name) + 1;
1247         if (name_len > MAX_INST_NAME_LEN)
1248                 return -ENAMETOOLONG;
1249
1250         ptr = kstrndup(name, name_len, GFP_KERNEL);
1251         if (!ptr)
1252                 return -ENOMEM;
1253
1254         fi_acc = to_fi_acc(fi);
1255         fi_acc->name = ptr;
1256         return 0;
1257 }
1258
1259 static void acc_free_inst(struct usb_function_instance *fi)
1260 {
1261         struct acc_instance *fi_acc;
1262
1263         fi_acc = to_fi_acc(fi);
1264         kfree(fi_acc->name);
1265         acc_cleanup();
1266 }
1267
1268 static struct usb_function_instance *acc_alloc_inst(void)
1269 {
1270         struct acc_instance *fi_acc;
1271         struct acc_dev *dev;
1272         int err;
1273
1274         fi_acc = kzalloc(sizeof(*fi_acc), GFP_KERNEL);
1275         if (!fi_acc)
1276                 return ERR_PTR(-ENOMEM);
1277         fi_acc->func_inst.set_inst_name = acc_set_inst_name;
1278         fi_acc->func_inst.free_func_inst = acc_free_inst;
1279
1280         err = acc_setup();
1281         if (err) {
1282                 kfree(fi_acc);
1283                 pr_err("Error setting ACCESSORY\n");
1284                 return ERR_PTR(err);
1285         }
1286
1287         config_group_init_type_name(&fi_acc->func_inst.group,
1288                                         "", &acc_func_type);
1289         dev = _acc_dev;
1290         return  &fi_acc->func_inst;
1291 }
1292
1293 static void acc_free(struct usb_function *f)
1294 {
1295 /*NO-OP: no function specific resource allocation in mtp_alloc*/
1296 }
1297
1298 int acc_ctrlrequest_configfs(struct usb_function *f,
1299                         const struct usb_ctrlrequest *ctrl) {
1300         if (f->config != NULL && f->config->cdev != NULL)
1301                 return acc_ctrlrequest(f->config->cdev, ctrl);
1302         else
1303                 return -1;
1304 }
1305
1306 static struct usb_function *acc_alloc(struct usb_function_instance *fi)
1307 {
1308         struct acc_dev *dev = _acc_dev;
1309
1310         pr_info("acc_alloc\n");
1311
1312         dev->function.name = "accessory";
1313         dev->function.strings = acc_strings,
1314         dev->function.fs_descriptors = fs_acc_descs;
1315         dev->function.hs_descriptors = hs_acc_descs;
1316         dev->function.bind = acc_function_bind_configfs;
1317         dev->function.unbind = acc_function_unbind;
1318         dev->function.set_alt = acc_function_set_alt;
1319         dev->function.disable = acc_function_disable;
1320         dev->function.free_func = acc_free;
1321         dev->function.setup = acc_ctrlrequest_configfs;
1322
1323         return &dev->function;
1324 }
1325 DECLARE_USB_FUNCTION_INIT(accessory, acc_alloc_inst, acc_alloc);
1326 MODULE_LICENSE("GPL");