drivers/usb/misc/iowarrior.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Native support for the I/O-Warrior USB devices
   4  *
   5  *  Copyright (c) 2003-2005  Code Mercenaries GmbH
   6  *  written by Christian Lucht <lucht@codemercs.com>
   7  *
   8  *  based on
   9
  10  *  usb-skeleton.c by Greg Kroah-Hartman  <greg@kroah.com>
  11  *  brlvger.c by Stephane Dalton  <sdalton@videotron.ca>
  12  *           and St�hane Doyon   <s.doyon@videotron.ca>
  13  *
  14  *  Released under the GPLv2.
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/usb.h>
  19 #include <linux/slab.h>
  20 #include <linux/sched.h>
  21 #include <linux/mutex.h>
  22 #include <linux/poll.h>
  23 #include <linux/usb/iowarrior.h>
  24
  25 #define DRIVER_AUTHOR "Christian Lucht <lucht@codemercs.com>"
  26 #define DRIVER_DESC "USB IO-Warrior driver"
  27
  28 #define USB_VENDOR_ID_CODEMERCS         1984
  29 /* low speed iowarrior */
  30 #define USB_DEVICE_ID_CODEMERCS_IOW40   0x1500
  31 #define USB_DEVICE_ID_CODEMERCS_IOW24   0x1501
  32 #define USB_DEVICE_ID_CODEMERCS_IOWPV1  0x1511
  33 #define USB_DEVICE_ID_CODEMERCS_IOWPV2  0x1512
  34 /* full speed iowarrior */
  35 #define USB_DEVICE_ID_CODEMERCS_IOW56   0x1503
  36
  37 /* Get a minor range for your devices from the usb maintainer */
  38 #ifdef CONFIG_USB_DYNAMIC_MINORS
  39 #define IOWARRIOR_MINOR_BASE    0
  40 #else
  41 #define IOWARRIOR_MINOR_BASE    208     // SKELETON_MINOR_BASE 192 + 16, not official yet
  42 #endif
  43
  44 /* interrupt input queue size */
  45 #define MAX_INTERRUPT_BUFFER 16
  46 /*
  47    maximum number of urbs that are submitted for writes at the same time,
  48    this applies to the IOWarrior56 only!
  49    IOWarrior24 and IOWarrior40 use synchronous usb_control_msg calls.
  50 */
  51 #define MAX_WRITES_IN_FLIGHT 4
  52
  53 MODULE_AUTHOR(DRIVER_AUTHOR);
  54 MODULE_DESCRIPTION(DRIVER_DESC);
  55 MODULE_LICENSE("GPL");
  56
  57 /* Module parameters */
  58 static DEFINE_MUTEX(iowarrior_mutex);
  59
  60 static struct usb_driver iowarrior_driver;
  61 static DEFINE_MUTEX(iowarrior_open_disc_lock);
  62
  63 /*--------------*/
  64 /*     data     */
  65 /*--------------*/
  66
  67 /* Structure to hold all of our device specific stuff */
  68 struct iowarrior {
  69         struct mutex mutex;                     /* locks this structure */
  70         struct usb_device *udev;                /* save off the usb device pointer */
  71         struct usb_interface *interface;        /* the interface for this device */
  72         unsigned char minor;                    /* the starting minor number for this device */
  73         struct usb_endpoint_descriptor *int_out_endpoint;       /* endpoint for reading (needed for IOW56 only) */
  74         struct usb_endpoint_descriptor *int_in_endpoint;        /* endpoint for reading */
  75         struct urb *int_in_urb;         /* the urb for reading data */
  76         unsigned char *int_in_buffer;   /* buffer for data to be read */
  77         unsigned char serial_number;    /* to detect lost packages */
  78         unsigned char *read_queue;      /* size is MAX_INTERRUPT_BUFFER * packet size */
  79         wait_queue_head_t read_wait;
  80         wait_queue_head_t write_wait;   /* wait-queue for writing to the device */
  81         atomic_t write_busy;            /* number of write-urbs submitted */
  82         atomic_t read_idx;
  83         atomic_t intr_idx;
  84         atomic_t overflow_flag;         /* signals an index 'rollover' */
  85         int present;                    /* this is 1 as long as the device is connected */
  86         int opened;                     /* this is 1 if the device is currently open */
  87         char chip_serial[9];            /* the serial number string of the chip connected */
  88         int report_size;                /* number of bytes in a report */
  89         u16 product_id;
  90 };
  91
  92 /*--------------*/
  93 /*    globals   */
  94 /*--------------*/
  95
  96 /*
  97  *  USB spec identifies 5 second timeouts.
  98  */
  99 #define GET_TIMEOUT 5
 100 #define USB_REQ_GET_REPORT  0x01
 101 //#if 0
 102 static int usb_get_report(struct usb_device *dev,
 103                           struct usb_host_interface *inter, unsigned char type,
 104                           unsigned char id, void *buf, int size)
 105 {
 106         return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
 107                                USB_REQ_GET_REPORT,
 108                                USB_DIR_IN | USB_TYPE_CLASS |
 109                                USB_RECIP_INTERFACE, (type << 8) + id,
 110                                inter->desc.bInterfaceNumber, buf, size,
 111                                GET_TIMEOUT*HZ);
 112 }
 113 //#endif
 114
 115 #define USB_REQ_SET_REPORT 0x09
 116
 117 static int usb_set_report(struct usb_interface *intf, unsigned char type,
 118                           unsigned char id, void *buf, int size)
 119 {
 120         return usb_control_msg(interface_to_usbdev(intf),
 121                                usb_sndctrlpipe(interface_to_usbdev(intf), 0),
 122                                USB_REQ_SET_REPORT,
 123                                USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 124                                (type << 8) + id,
 125                                intf->cur_altsetting->desc.bInterfaceNumber, buf,
 126                                size, HZ);
 127 }
 128
 129 /*---------------------*/
 130 /* driver registration */
 131 /*---------------------*/
 132 /* table of devices that work with this driver */
 133 static const struct usb_device_id iowarrior_ids[] = {
 134         {USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW40)},
 135         {USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW24)},
 136         {USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV1)},
 137         {USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV2)},
 138         {USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW56)},
 139         {}                      /* Terminating entry */
 140 };
 141 MODULE_DEVICE_TABLE(usb, iowarrior_ids);
 142
 143 /*
 144  * USB callback handler for reading data
 145  */
 146 static void iowarrior_callback(struct urb *urb)
 147 {
 148         struct iowarrior *dev = urb->context;
 149         int intr_idx;
 150         int read_idx;
 151         int aux_idx;
 152         int offset;
 153         int status = urb->status;
 154         int retval;
 155
 156         switch (status) {
 157         case 0:
 158                 /* success */
 159                 break;
 160         case -ECONNRESET:
 161         case -ENOENT:
 162         case -ESHUTDOWN:
 163                 return;
 164         default:
 165                 goto exit;
 166         }
 167
 168         intr_idx = atomic_read(&dev->intr_idx);
 169         /* aux_idx become previous intr_idx */
 170         aux_idx = (intr_idx == 0) ? (MAX_INTERRUPT_BUFFER - 1) : (intr_idx - 1);
 171         read_idx = atomic_read(&dev->read_idx);
 172
 173         /* queue is not empty and it's interface 0 */
 174         if ((intr_idx != read_idx)
 175             && (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0)) {
 176                 /* + 1 for serial number */
 177                 offset = aux_idx * (dev->report_size + 1);
 178                 if (!memcmp
 179                     (dev->read_queue + offset, urb->transfer_buffer,
 180                      dev->report_size)) {
 181                         /* equal values on interface 0 will be ignored */
 182                         goto exit;
 183                 }
 184         }
 185
 186         /* aux_idx become next intr_idx */
 187         aux_idx = (intr_idx == (MAX_INTERRUPT_BUFFER - 1)) ? 0 : (intr_idx + 1);
 188         if (read_idx == aux_idx) {
 189                 /* queue full, dropping oldest input */
 190                 read_idx = (++read_idx == MAX_INTERRUPT_BUFFER) ? 0 : read_idx;
 191                 atomic_set(&dev->read_idx, read_idx);
 192                 atomic_set(&dev->overflow_flag, 1);
 193         }
 194
 195         /* +1 for serial number */
 196         offset = intr_idx * (dev->report_size + 1);
 197         memcpy(dev->read_queue + offset, urb->transfer_buffer,
 198                dev->report_size);
 199         *(dev->read_queue + offset + (dev->report_size)) = dev->serial_number++;
 200
 201         atomic_set(&dev->intr_idx, aux_idx);
 202         /* tell the blocking read about the new data */
 203         wake_up_interruptible(&dev->read_wait);
 204
 205 exit:
 206         retval = usb_submit_urb(urb, GFP_ATOMIC);
 207         if (retval)
 208                 dev_err(&dev->interface->dev, "%s - usb_submit_urb failed with result %d\n",
 209                         __func__, retval);
 210
 211 }
 212
 213 /*
 214  * USB Callback handler for write-ops
 215  */
 216 static void iowarrior_write_callback(struct urb *urb)
 217 {
 218         struct iowarrior *dev;
 219         int status = urb->status;
 220
 221         dev = urb->context;
 222         /* sync/async unlink faults aren't errors */
 223         if (status &&
 224             !(status == -ENOENT ||
 225               status == -ECONNRESET || status == -ESHUTDOWN)) {
 226                 dev_dbg(&dev->interface->dev,
 227                         "nonzero write bulk status received: %d\n", status);
 228         }
 229         /* free up our allocated buffer */
 230         usb_free_coherent(urb->dev, urb->transfer_buffer_length,
 231                           urb->transfer_buffer, urb->transfer_dma);
 232         /* tell a waiting writer the interrupt-out-pipe is available again */
 233         atomic_dec(&dev->write_busy);
 234         wake_up_interruptible(&dev->write_wait);
 235 }
 236
 237 /**
 238  *      iowarrior_delete
 239  */
 240 static inline void iowarrior_delete(struct iowarrior *dev)
 241 {
 242         dev_dbg(&dev->interface->dev, "minor %d\n", dev->minor);
 243         kfree(dev->int_in_buffer);
 244         usb_free_urb(dev->int_in_urb);
 245         kfree(dev->read_queue);
 246         kfree(dev);
 247 }
 248
 249 /*---------------------*/
 250 /* fops implementation */
 251 /*---------------------*/
 252
 253 static int read_index(struct iowarrior *dev)
 254 {
 255         int intr_idx, read_idx;
 256
 257         read_idx = atomic_read(&dev->read_idx);
 258         intr_idx = atomic_read(&dev->intr_idx);
 259
 260         return (read_idx == intr_idx ? -1 : read_idx);
 261 }
 262
 263 /**
 264  *  iowarrior_read
 265  */
 266 static ssize_t iowarrior_read(struct file *file, char __user *buffer,
 267                               size_t count, loff_t *ppos)
 268 {
 269         struct iowarrior *dev;
 270         int read_idx;
 271         int offset;
 272
 273         dev = file->private_data;
 274
 275         /* verify that the device wasn't unplugged */
 276         if (!dev || !dev->present)
 277                 return -ENODEV;
 278
 279         dev_dbg(&dev->interface->dev, "minor %d, count = %zd\n",
 280                 dev->minor, count);
 281
 282         /* read count must be packet size (+ time stamp) */
 283         if ((count != dev->report_size)
 284             && (count != (dev->report_size + 1)))
 285                 return -EINVAL;
 286
 287         /* repeat until no buffer overrun in callback handler occur */
 288         do {
 289                 atomic_set(&dev->overflow_flag, 0);
 290                 if ((read_idx = read_index(dev)) == -1) {
 291                         /* queue empty */
 292                         if (file->f_flags & O_NONBLOCK)
 293                                 return -EAGAIN;
 294                         else {
 295                                 //next line will return when there is either new data, or the device is unplugged
 296                                 int r = wait_event_interruptible(dev->read_wait,
 297                                                                  (!dev->present
 298                                                                   || (read_idx =
 299                                                                       read_index
 300                                                                       (dev)) !=
 301                                                                   -1));
 302                                 if (r) {
 303                                         //we were interrupted by a signal
 304                                         return -ERESTART;
 305                                 }
 306                                 if (!dev->present) {
 307                                         //The device was unplugged
 308                                         return -ENODEV;
 309                                 }
 310                                 if (read_idx == -1) {
 311                                         // Can this happen ???
 312                                         return 0;
 313                                 }
 314                         }
 315                 }
 316
 317                 offset = read_idx * (dev->report_size + 1);
 318                 if (copy_to_user(buffer, dev->read_queue + offset, count)) {
 319                         return -EFAULT;
 320                 }
 321         } while (atomic_read(&dev->overflow_flag));
 322
 323         read_idx = ++read_idx == MAX_INTERRUPT_BUFFER ? 0 : read_idx;
 324         atomic_set(&dev->read_idx, read_idx);
 325         return count;
 326 }
 327
 328 /*
 329  * iowarrior_write
 330  */
 331 static ssize_t iowarrior_write(struct file *file,
 332                                const char __user *user_buffer,
 333                                size_t count, loff_t *ppos)
 334 {
 335         struct iowarrior *dev;
 336         int retval = 0;
 337         char *buf = NULL;       /* for IOW24 and IOW56 we need a buffer */
 338         struct urb *int_out_urb = NULL;
 339
 340         dev = file->private_data;
 341
 342         mutex_lock(&dev->mutex);
 343         /* verify that the device wasn't unplugged */
 344         if (!dev->present) {
 345                 retval = -ENODEV;
 346                 goto exit;
 347         }
 348         dev_dbg(&dev->interface->dev, "minor %d, count = %zd\n",
 349                 dev->minor, count);
 350         /* if count is 0 we're already done */
 351         if (count == 0) {
 352                 retval = 0;
 353                 goto exit;
 354         }
 355         /* We only accept full reports */
 356         if (count != dev->report_size) {
 357                 retval = -EINVAL;
 358                 goto exit;
 359         }
 360         switch (dev->product_id) {
 361         case USB_DEVICE_ID_CODEMERCS_IOW24:
 362         case USB_DEVICE_ID_CODEMERCS_IOWPV1:
 363         case USB_DEVICE_ID_CODEMERCS_IOWPV2:
 364         case USB_DEVICE_ID_CODEMERCS_IOW40:
 365                 /* IOW24 and IOW40 use a synchronous call */
 366                 buf = memdup_user(user_buffer, count);
 367                 if (IS_ERR(buf)) {
 368                         retval = PTR_ERR(buf);
 369                         goto exit;
 370                 }
 371                 retval = usb_set_report(dev->interface, 2, 0, buf, count);
 372                 kfree(buf);
 373                 goto exit;
 374                 break;
 375         case USB_DEVICE_ID_CODEMERCS_IOW56:
 376                 /* The IOW56 uses asynchronous IO and more urbs */
 377                 if (atomic_read(&dev->write_busy) == MAX_WRITES_IN_FLIGHT) {
 378                         /* Wait until we are below the limit for submitted urbs */
 379                         if (file->f_flags & O_NONBLOCK) {
 380                                 retval = -EAGAIN;
 381                                 goto exit;
 382                         } else {
 383                                 retval = wait_event_interruptible(dev->write_wait,
 384                                                                   (!dev->present || (atomic_read (&dev-> write_busy) < MAX_WRITES_IN_FLIGHT)));
 385                                 if (retval) {
 386                                         /* we were interrupted by a signal */
 387                                         retval = -ERESTART;
 388                                         goto exit;
 389                                 }
 390                                 if (!dev->present) {
 391                                         /* The device was unplugged */
 392                                         retval = -ENODEV;
 393                                         goto exit;
 394                                 }
 395                                 if (!dev->opened) {
 396                                         /* We were closed while waiting for an URB */
 397                                         retval = -ENODEV;
 398                                         goto exit;
 399                                 }
 400                         }
 401                 }
 402                 atomic_inc(&dev->write_busy);
 403                 int_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 404                 if (!int_out_urb) {
 405                         retval = -ENOMEM;
 406                         goto error_no_urb;
 407                 }
 408                 buf = usb_alloc_coherent(dev->udev, dev->report_size,
 409                                          GFP_KERNEL, &int_out_urb->transfer_dma);
 410                 if (!buf) {
 411                         retval = -ENOMEM;
 412                         dev_dbg(&dev->interface->dev,
 413                                 "Unable to allocate buffer\n");
 414                         goto error_no_buffer;
 415                 }
 416                 usb_fill_int_urb(int_out_urb, dev->udev,
 417                                  usb_sndintpipe(dev->udev,
 418                                                 dev->int_out_endpoint->bEndpointAddress),
 419                                  buf, dev->report_size,
 420                                  iowarrior_write_callback, dev,
 421                                  dev->int_out_endpoint->bInterval);
 422                 int_out_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 423                 if (copy_from_user(buf, user_buffer, count)) {
 424                         retval = -EFAULT;
 425                         goto error;
 426                 }
 427                 retval = usb_submit_urb(int_out_urb, GFP_KERNEL);
 428                 if (retval) {
 429                         dev_dbg(&dev->interface->dev,
 430                                 "submit error %d for urb nr.%d\n",
 431                                 retval, atomic_read(&dev->write_busy));
 432                         goto error;
 433                 }
 434                 /* submit was ok */
 435                 retval = count;
 436                 usb_free_urb(int_out_urb);
 437                 goto exit;
 438                 break;
 439         default:
 440                 /* what do we have here ? An unsupported Product-ID ? */
 441                 dev_err(&dev->interface->dev, "%s - not supported for product=0x%x\n",
 442                         __func__, dev->product_id);
 443                 retval = -EFAULT;
 444                 goto exit;
 445                 break;
 446         }
 447 error:
 448         usb_free_coherent(dev->udev, dev->report_size, buf,
 449                           int_out_urb->transfer_dma);
 450 error_no_buffer:
 451         usb_free_urb(int_out_urb);
 452 error_no_urb:
 453         atomic_dec(&dev->write_busy);
 454         wake_up_interruptible(&dev->write_wait);
 455 exit:
 456         mutex_unlock(&dev->mutex);
 457         return retval;
 458 }
 459
 460 /**
 461  *      iowarrior_ioctl
 462  */
 463 static long iowarrior_ioctl(struct file *file, unsigned int cmd,
 464                                                         unsigned long arg)
 465 {
 466         struct iowarrior *dev = NULL;
 467         __u8 *buffer;
 468         __u8 __user *user_buffer;
 469         int retval;
 470         int io_res;             /* checks for bytes read/written and copy_to/from_user results */
 471
 472         dev = file->private_data;
 473         if (!dev)
 474                 return -ENODEV;
 475
 476         buffer = kzalloc(dev->report_size, GFP_KERNEL);
 477         if (!buffer)
 478                 return -ENOMEM;
 479
 480         /* lock this object */
 481         mutex_lock(&iowarrior_mutex);
 482         mutex_lock(&dev->mutex);
 483
 484         /* verify that the device wasn't unplugged */
 485         if (!dev->present) {
 486                 retval = -ENODEV;
 487                 goto error_out;
 488         }
 489
 490         dev_dbg(&dev->interface->dev, "minor %d, cmd 0x%.4x, arg %ld\n",
 491                 dev->minor, cmd, arg);
 492
 493         retval = 0;
 494         io_res = 0;
 495         switch (cmd) {
 496         case IOW_WRITE:
 497                 if (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW24 ||
 498                     dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV1 ||
 499                     dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV2 ||
 500                     dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW40) {
 501                         user_buffer = (__u8 __user *)arg;
 502                         io_res = copy_from_user(buffer, user_buffer,
 503                                                 dev->report_size);
 504                         if (io_res) {
 505                                 retval = -EFAULT;
 506                         } else {
 507                                 io_res = usb_set_report(dev->interface, 2, 0,
 508                                                         buffer,
 509                                                         dev->report_size);
 510                                 if (io_res < 0)
 511                                         retval = io_res;
 512                         }
 513                 } else {
 514                         retval = -EINVAL;
 515                         dev_err(&dev->interface->dev,
 516                                 "ioctl 'IOW_WRITE' is not supported for product=0x%x.\n",
 517                                 dev->product_id);
 518                 }
 519                 break;
 520         case IOW_READ:
 521                 user_buffer = (__u8 __user *)arg;
 522                 io_res = usb_get_report(dev->udev,
 523                                         dev->interface->cur_altsetting, 1, 0,
 524                                         buffer, dev->report_size);
 525                 if (io_res < 0)
 526                         retval = io_res;
 527                 else {
 528                         io_res = copy_to_user(user_buffer, buffer, dev->report_size);
 529                         if (io_res)
 530                                 retval = -EFAULT;
 531                 }
 532                 break;
 533         case IOW_GETINFO:
 534                 {
 535                         /* Report available information for the device */
 536                         struct iowarrior_info info;
 537                         /* needed for power consumption */
 538                         struct usb_config_descriptor *cfg_descriptor = &dev->udev->actconfig->desc;
 539
 540                         memset(&info, 0, sizeof(info));
 541                         /* directly from the descriptor */
 542                         info.vendor = le16_to_cpu(dev->udev->descriptor.idVendor);
 543                         info.product = dev->product_id;
 544                         info.revision = le16_to_cpu(dev->udev->descriptor.bcdDevice);
 545
 546                         /* 0==UNKNOWN, 1==LOW(usb1.1) ,2=FULL(usb1.1), 3=HIGH(usb2.0) */
 547                         info.speed = dev->udev->speed;
 548                         info.if_num = dev->interface->cur_altsetting->desc.bInterfaceNumber;
 549                         info.report_size = dev->report_size;
 550
 551                         /* serial number string has been read earlier 8 chars or empty string */
 552                         memcpy(info.serial, dev->chip_serial,
 553                                sizeof(dev->chip_serial));
 554                         if (cfg_descriptor == NULL) {
 555                                 info.power = -1;        /* no information available */
 556                         } else {
 557                                 /* the MaxPower is stored in units of 2mA to make it fit into a byte-value */
 558                                 info.power = cfg_descriptor->bMaxPower * 2;
 559                         }
 560                         io_res = copy_to_user((struct iowarrior_info __user *)arg, &info,
 561                                          sizeof(struct iowarrior_info));
 562                         if (io_res)
 563                                 retval = -EFAULT;
 564                         break;
 565                 }
 566         default:
 567                 /* return that we did not understand this ioctl call */
 568                 retval = -ENOTTY;
 569                 break;
 570         }
 571 error_out:
 572         /* unlock the device */
 573         mutex_unlock(&dev->mutex);
 574         mutex_unlock(&iowarrior_mutex);
 575         kfree(buffer);
 576         return retval;
 577 }
 578
 579 /**
 580  *      iowarrior_open
 581  */
 582 static int iowarrior_open(struct inode *inode, struct file *file)
 583 {
 584         struct iowarrior *dev = NULL;
 585         struct usb_interface *interface;
 586         int subminor;
 587         int retval = 0;
 588
 589         mutex_lock(&iowarrior_mutex);
 590         subminor = iminor(inode);
 591
 592         interface = usb_find_interface(&iowarrior_driver, subminor);
 593         if (!interface) {
 594                 mutex_unlock(&iowarrior_mutex);
 595                 printk(KERN_ERR "%s - error, can't find device for minor %d\n",
 596                        __func__, subminor);
 597                 return -ENODEV;
 598         }
 599
 600         mutex_lock(&iowarrior_open_disc_lock);
 601         dev = usb_get_intfdata(interface);
 602         if (!dev) {
 603                 mutex_unlock(&iowarrior_open_disc_lock);
 604                 mutex_unlock(&iowarrior_mutex);
 605                 return -ENODEV;
 606         }
 607
 608         mutex_lock(&dev->mutex);
 609         mutex_unlock(&iowarrior_open_disc_lock);
 610
 611         /* Only one process can open each device, no sharing. */
 612         if (dev->opened) {
 613                 retval = -EBUSY;
 614                 goto out;
 615         }
 616
 617         /* setup interrupt handler for receiving values */
 618         if ((retval = usb_submit_urb(dev->int_in_urb, GFP_KERNEL)) < 0) {
 619                 dev_err(&interface->dev, "Error %d while submitting URB\n", retval);
 620                 retval = -EFAULT;
 621                 goto out;
 622         }
 623         /* increment our usage count for the driver */
 624         ++dev->opened;
 625         /* save our object in the file's private structure */
 626         file->private_data = dev;
 627         retval = 0;
 628
 629 out:
 630         mutex_unlock(&dev->mutex);
 631         mutex_unlock(&iowarrior_mutex);
 632         return retval;
 633 }
 634
 635 /**
 636  *      iowarrior_release
 637  */
 638 static int iowarrior_release(struct inode *inode, struct file *file)
 639 {
 640         struct iowarrior *dev;
 641         int retval = 0;
 642
 643         dev = file->private_data;
 644         if (!dev)
 645                 return -ENODEV;
 646
 647         dev_dbg(&dev->interface->dev, "minor %d\n", dev->minor);
 648
 649         /* lock our device */
 650         mutex_lock(&dev->mutex);
 651
 652         if (dev->opened <= 0) {
 653                 retval = -ENODEV;       /* close called more than once */
 654                 mutex_unlock(&dev->mutex);
 655         } else {
 656                 dev->opened = 0;        /* we're closing now */
 657                 retval = 0;
 658                 if (dev->present) {
 659                         /*
 660                            The device is still connected so we only shutdown
 661                            pending read-/write-ops.
 662                          */
 663                         usb_kill_urb(dev->int_in_urb);
 664                         wake_up_interruptible(&dev->read_wait);
 665                         wake_up_interruptible(&dev->write_wait);
 666                         mutex_unlock(&dev->mutex);
 667                 } else {
 668                         /* The device was unplugged, cleanup resources */
 669                         mutex_unlock(&dev->mutex);
 670                         iowarrior_delete(dev);
 671                 }
 672         }
 673         return retval;
 674 }
 675
 676 static __poll_t iowarrior_poll(struct file *file, poll_table * wait)
 677 {
 678         struct iowarrior *dev = file->private_data;
 679         __poll_t mask = 0;
 680
 681         if (!dev->present)
 682                 return EPOLLERR | EPOLLHUP;
 683
 684         poll_wait(file, &dev->read_wait, wait);
 685         poll_wait(file, &dev->write_wait, wait);
 686
 687         if (!dev->present)
 688                 return EPOLLERR | EPOLLHUP;
 689
 690         if (read_index(dev) != -1)
 691                 mask |= EPOLLIN | EPOLLRDNORM;
 692
 693         if (atomic_read(&dev->write_busy) < MAX_WRITES_IN_FLIGHT)
 694                 mask |= EPOLLOUT | EPOLLWRNORM;
 695         return mask;
 696 }
 697
 698 /*
 699  * File operations needed when we register this driver.
 700  * This assumes that this driver NEEDS file operations,
 701  * of course, which means that the driver is expected
 702  * to have a node in the /dev directory. If the USB
 703  * device were for a network interface then the driver
 704  * would use "struct net_driver" instead, and a serial
 705  * device would use "struct tty_driver".
 706  */
 707 static const struct file_operations iowarrior_fops = {
 708         .owner = THIS_MODULE,
 709         .write = iowarrior_write,
 710         .read = iowarrior_read,
 711         .unlocked_ioctl = iowarrior_ioctl,
 712         .open = iowarrior_open,
 713         .release = iowarrior_release,
 714         .poll = iowarrior_poll,
 715         .llseek = noop_llseek,
 716 };
 717
 718 static char *iowarrior_devnode(struct device *dev, umode_t *mode)
 719 {
 720         return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
 721 }
 722
 723 /*
 724  * usb class driver info in order to get a minor number from the usb core,
 725  * and to have the device registered with devfs and the driver core
 726  */
 727 static struct usb_class_driver iowarrior_class = {
 728         .name = "iowarrior%d",
 729         .devnode = iowarrior_devnode,
 730         .fops = &iowarrior_fops,
 731         .minor_base = IOWARRIOR_MINOR_BASE,
 732 };
 733
 734 /*---------------------------------*/
 735 /*  probe and disconnect functions */
 736 /*---------------------------------*/
 737 /**
 738  *      iowarrior_probe
 739  *
 740  *      Called by the usb core when a new device is connected that it thinks
 741  *      this driver might be interested in.
 742  */
 743 static int iowarrior_probe(struct usb_interface *interface,
 744                            const struct usb_device_id *id)
 745 {
 746         struct usb_device *udev = interface_to_usbdev(interface);
 747         struct iowarrior *dev = NULL;
 748         struct usb_host_interface *iface_desc;
 749         int retval = -ENOMEM;
 750         int res;
 751
 752         /* allocate memory for our device state and initialize it */
 753         dev = kzalloc(sizeof(struct iowarrior), GFP_KERNEL);
 754         if (!dev)
 755                 return retval;
 756
 757         mutex_init(&dev->mutex);
 758
 759         atomic_set(&dev->intr_idx, 0);
 760         atomic_set(&dev->read_idx, 0);
 761         atomic_set(&dev->overflow_flag, 0);
 762         init_waitqueue_head(&dev->read_wait);
 763         atomic_set(&dev->write_busy, 0);
 764         init_waitqueue_head(&dev->write_wait);
 765
 766         dev->udev = udev;
 767         dev->interface = interface;
 768
 769         iface_desc = interface->cur_altsetting;
 770         dev->product_id = le16_to_cpu(udev->descriptor.idProduct);
 771
 772         res = usb_find_last_int_in_endpoint(iface_desc, &dev->int_in_endpoint);
 773         if (res) {
 774                 dev_err(&interface->dev, "no interrupt-in endpoint found\n");
 775                 retval = res;
 776                 goto error;
 777         }
 778
 779         if (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW56) {
 780                 res = usb_find_last_int_out_endpoint(iface_desc,
 781                                 &dev->int_out_endpoint);
 782                 if (res) {
 783                         dev_err(&interface->dev, "no interrupt-out endpoint found\n");
 784                         retval = res;
 785                         goto error;
 786                 }
 787         }
 788
 789         /* we have to check the report_size often, so remember it in the endianness suitable for our machine */
 790         dev->report_size = usb_endpoint_maxp(dev->int_in_endpoint);
 791         if ((dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) &&
 792             (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW56))
 793                 /* IOWarrior56 has wMaxPacketSize different from report size */
 794                 dev->report_size = 7;
 795
 796         /* create the urb and buffer for reading */
 797         dev->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 798         if (!dev->int_in_urb)
 799                 goto error;
 800         dev->int_in_buffer = kmalloc(dev->report_size, GFP_KERNEL);
 801         if (!dev->int_in_buffer)
 802                 goto error;
 803         usb_fill_int_urb(dev->int_in_urb, dev->udev,
 804                          usb_rcvintpipe(dev->udev,
 805                                         dev->int_in_endpoint->bEndpointAddress),
 806                          dev->int_in_buffer, dev->report_size,
 807                          iowarrior_callback, dev,
 808                          dev->int_in_endpoint->bInterval);
 809         /* create an internal buffer for interrupt data from the device */
 810         dev->read_queue =
 811             kmalloc_array(dev->report_size + 1, MAX_INTERRUPT_BUFFER,
 812                           GFP_KERNEL);
 813         if (!dev->read_queue)
 814                 goto error;
 815         /* Get the serial-number of the chip */
 816         memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
 817         usb_string(udev, udev->descriptor.iSerialNumber, dev->chip_serial,
 818                    sizeof(dev->chip_serial));
 819         if (strlen(dev->chip_serial) != 8)
 820                 memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
 821
 822         /* Set the idle timeout to 0, if this is interface 0 */
 823         if (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) {
 824             usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
 825                             0x0A,
 826                             USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0,
 827                             0, NULL, 0, USB_CTRL_SET_TIMEOUT);
 828         }
 829         /* allow device read and ioctl */
 830         dev->present = 1;
 831
 832         /* we can register the device now, as it is ready */
 833         usb_set_intfdata(interface, dev);
 834
 835         retval = usb_register_dev(interface, &iowarrior_class);
 836         if (retval) {
 837                 /* something prevented us from registering this driver */
 838                 dev_err(&interface->dev, "Not able to get a minor for this device.\n");
 839                 usb_set_intfdata(interface, NULL);
 840                 goto error;
 841         }
 842
 843         dev->minor = interface->minor;
 844
 845         /* let the user know what node this device is now attached to */
 846         dev_info(&interface->dev, "IOWarrior product=0x%x, serial=%s interface=%d "
 847                  "now attached to iowarrior%d\n", dev->product_id, dev->chip_serial,
 848                  iface_desc->desc.bInterfaceNumber, dev->minor - IOWARRIOR_MINOR_BASE);
 849         return retval;
 850
 851 error:
 852         iowarrior_delete(dev);
 853         return retval;
 854 }
 855
 856 /**
 857  *      iowarrior_disconnect
 858  *
 859  *      Called by the usb core when the device is removed from the system.
 860  */
 861 static void iowarrior_disconnect(struct usb_interface *interface)
 862 {
 863         struct iowarrior *dev;
 864         int minor;
 865
 866         dev = usb_get_intfdata(interface);
 867         mutex_lock(&iowarrior_open_disc_lock);
 868         usb_set_intfdata(interface, NULL);
 869         /* prevent device read, write and ioctl */
 870         dev->present = 0;
 871
 872         minor = dev->minor;
 873         mutex_unlock(&iowarrior_open_disc_lock);
 874         /* give back our minor - this will call close() locks need to be dropped at this point*/
 875
 876         usb_deregister_dev(interface, &iowarrior_class);
 877
 878         mutex_lock(&dev->mutex);
 879
 880         /* prevent device read, write and ioctl */
 881
 882         mutex_unlock(&dev->mutex);
 883
 884         if (dev->opened) {
 885                 /* There is a process that holds a filedescriptor to the device ,
 886                    so we only shutdown read-/write-ops going on.
 887                    Deleting the device is postponed until close() was called.
 888                  */
 889                 usb_kill_urb(dev->int_in_urb);
 890                 wake_up_interruptible(&dev->read_wait);
 891                 wake_up_interruptible(&dev->write_wait);
 892         } else {
 893                 /* no process is using the device, cleanup now */
 894                 iowarrior_delete(dev);
 895         }
 896
 897         dev_info(&interface->dev, "I/O-Warror #%d now disconnected\n",
 898                  minor - IOWARRIOR_MINOR_BASE);
 899 }
 900
 901 /* usb specific object needed to register this driver with the usb subsystem */
 902 static struct usb_driver iowarrior_driver = {
 903         .name = "iowarrior",
 904         .probe = iowarrior_probe,
 905         .disconnect = iowarrior_disconnect,
 906         .id_table = iowarrior_ids,
 907 };
 908
 909 module_usb_driver(iowarrior_driver);