drivers/usb/gadget/f_adb.c

   1 /*
   2  * Gadget Driver for Android ADB
   3  *
   4  * Copyright (C) 2008 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 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/poll.h>
  21 #include <linux/delay.h>
  22 #include <linux/wait.h>
  23 #include <linux/err.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/sched.h>
  26 #include <linux/types.h>
  27 #include <linux/device.h>
  28 #include <linux/miscdevice.h>
  29
  30 #define ADB_BULK_BUFFER_SIZE           4096
  31
  32 /* number of tx requests to allocate */
  33 #define TX_REQ_MAX 4
  34
  35 static const char adb_shortname[] = "android_adb";
  36
  37 struct adb_dev {
  38         struct usb_function function;
  39         struct usb_composite_dev *cdev;
  40         spinlock_t lock;
  41
  42         struct usb_ep *ep_in;
  43         struct usb_ep *ep_out;
  44
  45         int online;
  46         int error;
  47
  48         atomic_t read_excl;
  49         atomic_t write_excl;
  50         atomic_t open_excl;
  51
  52         struct list_head tx_idle;
  53
  54         wait_queue_head_t read_wq;
  55         wait_queue_head_t write_wq;
  56         struct usb_request *rx_req;
  57         int rx_done;
  58 };
  59
  60 static struct usb_interface_descriptor adb_interface_desc = {
  61         .bLength                = USB_DT_INTERFACE_SIZE,
  62         .bDescriptorType        = USB_DT_INTERFACE,
  63         .bInterfaceNumber       = 0,
  64         .bNumEndpoints          = 2,
  65         .bInterfaceClass        = 0xFF,
  66         .bInterfaceSubClass     = 0x42,
  67         .bInterfaceProtocol     = 1,
  68 };
  69
  70 static struct usb_endpoint_descriptor adb_highspeed_in_desc = {
  71         .bLength                = USB_DT_ENDPOINT_SIZE,
  72         .bDescriptorType        = USB_DT_ENDPOINT,
  73         .bEndpointAddress       = USB_DIR_IN,
  74         .bmAttributes           = USB_ENDPOINT_XFER_BULK,
  75         .wMaxPacketSize         = __constant_cpu_to_le16(64),
  76 };
  77
  78 static struct usb_endpoint_descriptor adb_highspeed_out_desc = {
  79         .bLength                = USB_DT_ENDPOINT_SIZE,
  80         .bDescriptorType        = USB_DT_ENDPOINT,
  81         .bEndpointAddress       = USB_DIR_OUT,
  82         .bmAttributes           = USB_ENDPOINT_XFER_BULK,
  83         .wMaxPacketSize         = __constant_cpu_to_le16(512),
  84 };
  85
  86 static struct usb_endpoint_descriptor adb_fullspeed_in_desc = {
  87         .bLength                = USB_DT_ENDPOINT_SIZE,
  88         .bDescriptorType        = USB_DT_ENDPOINT,
  89         .bEndpointAddress       = USB_DIR_IN,
  90         .bmAttributes           = USB_ENDPOINT_XFER_BULK,
  91 };
  92
  93 static struct usb_endpoint_descriptor adb_fullspeed_out_desc = {
  94         .bLength                = USB_DT_ENDPOINT_SIZE,
  95         .bDescriptorType        = USB_DT_ENDPOINT,
  96         .bEndpointAddress       = USB_DIR_OUT,
  97         .bmAttributes           = USB_ENDPOINT_XFER_BULK,
  98 };
  99
 100 static struct usb_descriptor_header *fs_adb_descs[] = {
 101         (struct usb_descriptor_header *) &adb_interface_desc,
 102         (struct usb_descriptor_header *) &adb_fullspeed_in_desc,
 103         (struct usb_descriptor_header *) &adb_fullspeed_out_desc,
 104         NULL,
 105 };
 106
 107 static struct usb_descriptor_header *hs_adb_descs[] = {
 108         (struct usb_descriptor_header *) &adb_interface_desc,
 109         (struct usb_descriptor_header *) &adb_highspeed_in_desc,
 110         (struct usb_descriptor_header *) &adb_highspeed_out_desc,
 111         NULL,
 112 };
 113
 114
 115 /* temporary variable used between adb_open() and adb_gadget_bind() */
 116 static struct adb_dev *_adb_dev;
 117
 118 static inline struct adb_dev *func_to_adb(struct usb_function *f)
 119 {
 120         return container_of(f, struct adb_dev, function);
 121 }
 122
 123
 124 static struct usb_request *adb_request_new(struct usb_ep *ep, int buffer_size)
 125 {
 126         struct usb_request *req = usb_ep_alloc_request(ep, GFP_KERNEL);
 127         if (!req)
 128                 return NULL;
 129
 130         /* now allocate buffers for the requests */
 131         req->buf = kmalloc(buffer_size, GFP_KERNEL);
 132         if (!req->buf) {
 133                 usb_ep_free_request(ep, req);
 134                 return NULL;
 135         }
 136
 137         return req;
 138 }
 139
 140 static void adb_request_free(struct usb_request *req, struct usb_ep *ep)
 141 {
 142         if (req) {
 143                 kfree(req->buf);
 144                 usb_ep_free_request(ep, req);
 145         }
 146 }
 147
 148 static inline int adb_lock(atomic_t *excl)
 149 {
 150         if (atomic_inc_return(excl) == 1) {
 151                 return 0;
 152         } else {
 153                 atomic_dec(excl);
 154                 return -1;
 155         }
 156 }
 157
 158 static inline void adb_unlock(atomic_t *excl)
 159 {
 160         atomic_dec(excl);
 161 }
 162
 163 /* add a request to the tail of a list */
 164 void adb_req_put(struct adb_dev *dev, struct list_head *head,
 165                 struct usb_request *req)
 166 {
 167         unsigned long flags;
 168
 169         spin_lock_irqsave(&dev->lock, flags);
 170         list_add_tail(&req->list, head);
 171         spin_unlock_irqrestore(&dev->lock, flags);
 172 }
 173
 174 /* remove a request from the head of a list */
 175 struct usb_request *adb_req_get(struct adb_dev *dev, struct list_head *head)
 176 {
 177         unsigned long flags;
 178         struct usb_request *req;
 179
 180         spin_lock_irqsave(&dev->lock, flags);
 181         if (list_empty(head)) {
 182                 req = 0;
 183         } else {
 184                 req = list_first_entry(head, struct usb_request, list);
 185                 list_del(&req->list);
 186         }
 187         spin_unlock_irqrestore(&dev->lock, flags);
 188         return req;
 189 }
 190
 191 static void adb_complete_in(struct usb_ep *ep, struct usb_request *req)
 192 {
 193         struct adb_dev *dev = _adb_dev;
 194
 195         if (req->status != 0)
 196                 dev->error = 1;
 197
 198         adb_req_put(dev, &dev->tx_idle, req);
 199
 200         wake_up(&dev->write_wq);
 201 }
 202
 203 static void adb_complete_out(struct usb_ep *ep, struct usb_request *req)
 204 {
 205         struct adb_dev *dev = _adb_dev;
 206
 207         dev->rx_done = 1;
 208         if (req->status != 0)
 209                 dev->error = 1;
 210
 211         wake_up(&dev->read_wq);
 212 }
 213
 214 static int adb_create_bulk_endpoints(struct adb_dev *dev,
 215                                 struct usb_endpoint_descriptor *in_desc,
 216                                 struct usb_endpoint_descriptor *out_desc)
 217 {
 218         struct usb_composite_dev *cdev = dev->cdev;
 219         struct usb_request *req;
 220         struct usb_ep *ep;
 221         int i;
 222
 223         DBG(cdev, "create_bulk_endpoints dev: %p\n", dev);
 224
 225         ep = usb_ep_autoconfig(cdev->gadget, in_desc);
 226         if (!ep) {
 227                 DBG(cdev, "usb_ep_autoconfig for ep_in failed\n");
 228                 return -ENODEV;
 229         }
 230         DBG(cdev, "usb_ep_autoconfig for ep_in got %s\n", ep->name);
 231         ep->driver_data = dev;          /* claim the endpoint */
 232         dev->ep_in = ep;
 233
 234         ep = usb_ep_autoconfig(cdev->gadget, out_desc);
 235         if (!ep) {
 236                 DBG(cdev, "usb_ep_autoconfig for ep_out failed\n");
 237                 return -ENODEV;
 238         }
 239         DBG(cdev, "usb_ep_autoconfig for adb ep_out got %s\n", ep->name);
 240         ep->driver_data = dev;          /* claim the endpoint */
 241         dev->ep_out = ep;
 242
 243         /* now allocate requests for our endpoints */
 244         req = adb_request_new(dev->ep_out, ADB_BULK_BUFFER_SIZE);
 245         if (!req)
 246                 goto fail;
 247         req->complete = adb_complete_out;
 248         dev->rx_req = req;
 249
 250         for (i = 0; i < TX_REQ_MAX; i++) {
 251                 req = adb_request_new(dev->ep_in, ADB_BULK_BUFFER_SIZE);
 252                 if (!req)
 253                         goto fail;
 254                 req->complete = adb_complete_in;
 255                 adb_req_put(dev, &dev->tx_idle, req);
 256         }
 257
 258         return 0;
 259
 260 fail:
 261         printk(KERN_ERR "adb_bind() could not allocate requests\n");
 262         return -1;
 263 }
 264
 265 static ssize_t adb_read(struct file *fp, char __user *buf,
 266                                 size_t count, loff_t *pos)
 267 {
 268         struct adb_dev *dev = fp->private_data;
 269         struct usb_request *req;
 270         int r = count, xfer;
 271         int ret;
 272
 273         pr_debug("adb_read(%d)\n", count);
 274         if (!_adb_dev)
 275                 return -ENODEV;
 276
 277         if (count > ADB_BULK_BUFFER_SIZE)
 278                 return -EINVAL;
 279
 280         if (adb_lock(&dev->read_excl))
 281                 return -EBUSY;
 282
 283         /* we will block until we're online */
 284         while (!(dev->online || dev->error)) {
 285                 pr_debug("adb_read: waiting for online state\n");
 286                 ret = wait_event_interruptible(dev->read_wq,
 287                                 (dev->online || dev->error));
 288                 if (ret < 0) {
 289                         adb_unlock(&dev->read_excl);
 290                         return ret;
 291                 }
 292         }
 293         if (dev->error) {
 294                 r = -EIO;
 295                 goto done;
 296         }
 297
 298 requeue_req:
 299         /* queue a request */
 300         req = dev->rx_req;
 301         req->length = count;
 302         dev->rx_done = 0;
 303         ret = usb_ep_queue(dev->ep_out, req, GFP_ATOMIC);
 304         if (ret < 0) {
 305                 pr_debug("adb_read: failed to queue req %p (%d)\n", req, ret);
 306                 r = -EIO;
 307                 dev->error = 1;
 308                 goto done;
 309         } else {
 310                 pr_debug("rx %p queue\n", req);
 311         }
 312
 313         /* wait for a request to complete */
 314         ret = wait_event_interruptible(dev->read_wq, dev->rx_done);
 315         if (ret < 0) {
 316                 dev->error = 1;
 317                 r = ret;
 318                 usb_ep_dequeue(dev->ep_out, req);
 319                 goto done;
 320         }
 321         if (!dev->error) {
 322                 /* If we got a 0-len packet, throw it back and try again. */
 323                 if (req->actual == 0)
 324                         goto requeue_req;
 325
 326                 pr_debug("rx %p %d\n", req, req->actual);
 327                 xfer = (req->actual < count) ? req->actual : count;
 328                 if (copy_to_user(buf, req->buf, xfer))
 329                         r = -EFAULT;
 330
 331         } else
 332                 r = -EIO;
 333
 334 done:
 335         adb_unlock(&dev->read_excl);
 336         pr_debug("adb_read returning %d\n", r);
 337         return r;
 338 }
 339
 340 static ssize_t adb_write(struct file *fp, const char __user *buf,
 341                                  size_t count, loff_t *pos)
 342 {
 343         struct adb_dev *dev = fp->private_data;
 344         struct usb_request *req = 0;
 345         int r = count, xfer;
 346         int ret;
 347
 348         if (!_adb_dev)
 349                 return -ENODEV;
 350         pr_debug("adb_write(%d)\n", count);
 351
 352         if (adb_lock(&dev->write_excl))
 353                 return -EBUSY;
 354
 355         while (count > 0) {
 356                 if (dev->error) {
 357                         pr_debug("adb_write dev->error\n");
 358                         r = -EIO;
 359                         break;
 360                 }
 361
 362                 /* get an idle tx request to use */
 363                 req = 0;
 364                 ret = wait_event_interruptible(dev->write_wq,
 365                         (req = adb_req_get(dev, &dev->tx_idle)) || dev->error);
 366
 367                 if (ret < 0) {
 368                         r = ret;
 369                         break;
 370                 }
 371
 372                 if (req != 0) {
 373                         if (count > ADB_BULK_BUFFER_SIZE)
 374                                 xfer = ADB_BULK_BUFFER_SIZE;
 375                         else
 376                                 xfer = count;
 377                         if (copy_from_user(req->buf, buf, xfer)) {
 378                                 r = -EFAULT;
 379                                 break;
 380                         }
 381
 382                         req->length = xfer;
 383                         ret = usb_ep_queue(dev->ep_in, req, GFP_ATOMIC);
 384                         if (ret < 0) {
 385                                 pr_debug("adb_write: xfer error %d\n", ret);
 386                                 dev->error = 1;
 387                                 r = -EIO;
 388                                 break;
 389                         }
 390
 391                         buf += xfer;
 392                         count -= xfer;
 393
 394                         /* zero this so we don't try to free it on error exit */
 395                         req = 0;
 396                 }
 397         }
 398
 399         if (req)
 400                 adb_req_put(dev, &dev->tx_idle, req);
 401
 402         adb_unlock(&dev->write_excl);
 403         pr_debug("adb_write returning %d\n", r);
 404         return r;
 405 }
 406
 407 static int adb_open(struct inode *ip, struct file *fp)
 408 {
 409         printk(KERN_INFO "adb_open\n");
 410         if (!_adb_dev)
 411                 return -ENODEV;
 412
 413         if (adb_lock(&_adb_dev->open_excl))
 414                 return -EBUSY;
 415
 416         fp->private_data = _adb_dev;
 417
 418         /* clear the error latch */
 419         _adb_dev->error = 0;
 420
 421         return 0;
 422 }
 423
 424 static int adb_release(struct inode *ip, struct file *fp)
 425 {
 426         printk(KERN_INFO "adb_release\n");
 427         adb_unlock(&_adb_dev->open_excl);
 428         return 0;
 429 }
 430
 431 /* file operations for ADB device /dev/android_adb */
 432 static struct file_operations adb_fops = {
 433         .owner = THIS_MODULE,
 434         .read = adb_read,
 435         .write = adb_write,
 436         .open = adb_open,
 437         .release = adb_release,
 438 };
 439
 440 static struct miscdevice adb_device = {
 441         .minor = MISC_DYNAMIC_MINOR,
 442         .name = adb_shortname,
 443         .fops = &adb_fops,
 444 };
 445
 446
 447
 448
 449 static int
 450 adb_function_bind(struct usb_configuration *c, struct usb_function *f)
 451 {
 452         struct usb_composite_dev *cdev = c->cdev;
 453         struct adb_dev  *dev = func_to_adb(f);
 454         int                     id;
 455         int                     ret;
 456
 457         dev->cdev = cdev;
 458         DBG(cdev, "adb_function_bind dev: %p\n", dev);
 459
 460         /* allocate interface ID(s) */
 461         id = usb_interface_id(c, f);
 462         if (id < 0)
 463                 return id;
 464         adb_interface_desc.bInterfaceNumber = id;
 465
 466         /* allocate endpoints */
 467         ret = adb_create_bulk_endpoints(dev, &adb_fullspeed_in_desc,
 468                         &adb_fullspeed_out_desc);
 469         if (ret)
 470                 return ret;
 471
 472         /* support high speed hardware */
 473         if (gadget_is_dualspeed(c->cdev->gadget)) {
 474                 adb_highspeed_in_desc.bEndpointAddress =
 475                         adb_fullspeed_in_desc.bEndpointAddress;
 476                 adb_highspeed_out_desc.bEndpointAddress =
 477                         adb_fullspeed_out_desc.bEndpointAddress;
 478         }
 479
 480         DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n",
 481                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 482                         f->name, dev->ep_in->name, dev->ep_out->name);
 483         return 0;
 484 }
 485
 486 static void
 487 adb_function_unbind(struct usb_configuration *c, struct usb_function *f)
 488 {
 489         struct adb_dev  *dev = func_to_adb(f);
 490         struct usb_request *req;
 491
 492
 493         dev->online = 0;
 494         dev->error = 1;
 495
 496         wake_up(&dev->read_wq);
 497
 498         adb_request_free(dev->rx_req, dev->ep_out);
 499         while ((req = adb_req_get(dev, &dev->tx_idle)))
 500                 adb_request_free(req, dev->ep_in);
 501 }
 502
 503 static int adb_function_set_alt(struct usb_function *f,
 504                 unsigned intf, unsigned alt)
 505 {
 506         struct adb_dev  *dev = func_to_adb(f);
 507         struct usb_composite_dev *cdev = f->config->cdev;
 508         int ret;
 509
 510         DBG(cdev, "adb_function_set_alt intf: %d alt: %d\n", intf, alt);
 511         ret = usb_ep_enable(dev->ep_in,
 512                         ep_choose(cdev->gadget,
 513                                 &adb_highspeed_in_desc,
 514                                 &adb_fullspeed_in_desc));
 515         if (ret)
 516                 return ret;
 517         ret = usb_ep_enable(dev->ep_out,
 518                         ep_choose(cdev->gadget,
 519                                 &adb_highspeed_out_desc,
 520                                 &adb_fullspeed_out_desc));
 521         if (ret) {
 522                 usb_ep_disable(dev->ep_in);
 523                 return ret;
 524         }
 525         dev->online = 1;
 526
 527         /* readers may be blocked waiting for us to go online */
 528         wake_up(&dev->read_wq);
 529         return 0;
 530 }
 531
 532 static void adb_function_disable(struct usb_function *f)
 533 {
 534         struct adb_dev  *dev = func_to_adb(f);
 535         struct usb_composite_dev        *cdev = dev->cdev;
 536
 537         DBG(cdev, "adb_function_disable cdev %p\n", cdev);
 538         dev->online = 0;
 539         dev->error = 1;
 540         usb_ep_disable(dev->ep_in);
 541         dev->ep_in->driver_data = NULL;
 542         usb_ep_disable(dev->ep_out);
 543         dev->ep_out->driver_data = NULL;
 544
 545         /* readers may be blocked waiting for us to go online */
 546         wake_up(&dev->read_wq);
 547
 548         VDBG(cdev, "%s disabled\n", dev->function.name);
 549 }
 550
 551 static int adb_bind_config(struct usb_configuration *c)
 552 {
 553         struct adb_dev *dev = _adb_dev;
 554
 555         dev->cdev = c->cdev;
 556         dev->function.name = "adb";
 557         dev->function.descriptors = fs_adb_descs;
 558         dev->function.hs_descriptors = hs_adb_descs;
 559         dev->function.bind = adb_function_bind;
 560         dev->function.unbind = adb_function_unbind;
 561         dev->function.set_alt = adb_function_set_alt;
 562         dev->function.disable = adb_function_disable;
 563
 564         return usb_add_function(c, &dev->function);
 565 }
 566
 567 static int adb_setup(void)
 568 {
 569         struct adb_dev *dev;
 570         int ret;
 571
 572         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 573         if (!dev)
 574                 return -ENOMEM;
 575
 576         spin_lock_init(&dev->lock);
 577
 578         init_waitqueue_head(&dev->read_wq);
 579         init_waitqueue_head(&dev->write_wq);
 580
 581         atomic_set(&dev->open_excl, 0);
 582         atomic_set(&dev->read_excl, 0);
 583         atomic_set(&dev->write_excl, 0);
 584
 585         INIT_LIST_HEAD(&dev->tx_idle);
 586
 587         _adb_dev = dev;
 588
 589         ret = misc_register(&adb_device);
 590         if (ret)
 591                 goto err;
 592
 593         return 0;
 594
 595 err:
 596         kfree(dev);
 597         printk(KERN_ERR "adb gadget driver failed to initialize\n");
 598         return ret;
 599 }
 600
 601 static void adb_cleanup(void)
 602 {
 603         misc_deregister(&adb_device);
 604
 605         kfree(_adb_dev);
 606         _adb_dev = NULL;
 607 }