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         struct usb_anchor submitted;
  91 };
  92
  93 /*--------------*/
  94 /*    globals   */
  95 /*--------------*/
  96
  97 /*
  98  *  USB spec identifies 5 second timeouts.
  99  */
 100 #define GET_TIMEOUT 5
 101 #define USB_REQ_GET_REPORT  0x01
 102 //#if 0
 103 static int usb_get_report(struct usb_device *dev,
 104                           struct usb_host_interface *inter, unsigned char type,
 105                           unsigned char id, void *buf, int size)
 106 {
 107         return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
 108                                USB_REQ_GET_REPORT,
 109                                USB_DIR_IN | USB_TYPE_CLASS |
 110                                USB_RECIP_INTERFACE, (type << 8) + id,
 111                                inter->desc.bInterfaceNumber, buf, size,
 112                                GET_TIMEOUT*HZ);
 113 }
 114 //#endif
 115
 116 #define USB_REQ_SET_REPORT 0x09
 117
 118 static int usb_set_report(struct usb_interface *intf, unsigned char type,
 119                           unsigned char id, void *buf, int size)
 120 {
 121         return usb_control_msg(interface_to_usbdev(intf),
 122                                usb_sndctrlpipe(interface_to_usbdev(intf), 0),
 123                                USB_REQ_SET_REPORT,
 124                                USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 125                                (type << 8) + id,
 126                                intf->cur_altsetting->desc.bInterfaceNumber, buf,
 127                                size, HZ);
 128 }
 129
 130 /*---------------------*/
 131 /* driver registration */
 132 /*---------------------*/
 133 /* table of devices that work with this driver */
 134 static const struct usb_device_id iowarrior_ids[] = {
 135         {USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW40)},
 136         {USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW24)},
 137         {USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV1)},
 138         {USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV2)},
 139         {USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW56)},
 140         {}                      /* Terminating entry */
 141 };
 142 MODULE_DEVICE_TABLE(usb, iowarrior_ids);
 143
 144 /*
 145  * USB callback handler for reading data
 146  */
 147 static void iowarrior_callback(struct urb *urb)
 148 {
 149         struct iowarrior *dev = urb->context;
 150         int intr_idx;
 151         int read_idx;
 152         int aux_idx;
 153         int offset;
 154         int status = urb->status;
 155         int retval;
 156
 157         switch (status) {
 158         case 0:
 159                 /* success */
 160                 break;
 161         case -ECONNRESET:
 162         case -ENOENT:
 163         case -ESHUTDOWN:
 164                 return;
 165         default:
 166                 goto exit;
 167         }
 168
 169         intr_idx = atomic_read(&dev->intr_idx);
 170         /* aux_idx become previous intr_idx */
 171         aux_idx = (intr_idx == 0) ? (MAX_INTERRUPT_BUFFER - 1) : (intr_idx - 1);
 172         read_idx = atomic_read(&dev->read_idx);
 173
 174         /* queue is not empty and it's interface 0 */
 175         if ((intr_idx != read_idx)
 176             && (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0)) {
 177                 /* + 1 for serial number */
 178                 offset = aux_idx * (dev->report_size + 1);
 179                 if (!memcmp
 180                     (dev->read_queue + offset, urb->transfer_buffer,
 181                      dev->report_size)) {
 182                         /* equal values on interface 0 will be ignored */
 183                         goto exit;
 184                 }
 185         }
 186
 187         /* aux_idx become next intr_idx */
 188         aux_idx = (intr_idx == (MAX_INTERRUPT_BUFFER - 1)) ? 0 : (intr_idx + 1);
 189         if (read_idx == aux_idx) {
 190                 /* queue full, dropping oldest input */
 191                 read_idx = (++read_idx == MAX_INTERRUPT_BUFFER) ? 0 : read_idx;
 192                 atomic_set(&dev->read_idx, read_idx);
 193                 atomic_set(&dev->overflow_flag, 1);
 194         }
 195
 196         /* +1 for serial number */
 197         offset = intr_idx * (dev->report_size + 1);
 198         memcpy(dev->read_queue + offset, urb->transfer_buffer,
 199                dev->report_size);
 200         *(dev->read_queue + offset + (dev->report_size)) = dev->serial_number++;
 201
 202         atomic_set(&dev->intr_idx, aux_idx);
 203         /* tell the blocking read about the new data */
 204         wake_up_interruptible(&dev->read_wait);
 205
 206 exit:
 207         retval = usb_submit_urb(urb, GFP_ATOMIC);
 208         if (retval)
 209                 dev_err(&dev->interface->dev, "%s - usb_submit_urb failed with result %d\n",
 210                         __func__, retval);
 211
 212 }
 213
 214 /*
 215  * USB Callback handler for write-ops
 216  */
 217 static void iowarrior_write_callback(struct urb *urb)
 218 {
 219         struct iowarrior *dev;
 220         int status = urb->status;
 221
 222         dev = urb->context;
 223         /* sync/async unlink faults aren't errors */
 224         if (status &&
 225             !(status == -ENOENT ||
 226               status == -ECONNRESET || status == -ESHUTDOWN)) {
 227                 dev_dbg(&dev->interface->dev,
 228                         "nonzero write bulk status received: %d\n", status);
 229         }
 230         /* free up our allocated buffer */
 231         usb_free_coherent(urb->dev, urb->transfer_buffer_length,
 232                           urb->transfer_buffer, urb->transfer_dma);
 233         /* tell a waiting writer the interrupt-out-pipe is available again */
 234         atomic_dec(&dev->write_busy);
 235         wake_up_interruptible(&dev->write_wait);
 236 }
 237
 238 /**
 239  *      iowarrior_delete
 240  */
 241 static inline void iowarrior_delete(struct iowarrior *dev)
 242 {
 243         dev_dbg(&dev->interface->dev, "minor %d\n", dev->minor);
 244         kfree(dev->int_in_buffer);
 245         usb_free_urb(dev->int_in_urb);
 246         kfree(dev->read_queue);
 247         usb_put_intf(dev->interface);
 248         kfree(dev);
 249 }
 250
 251 /*---------------------*/
 252 /* fops implementation */
 253 /*---------------------*/
 254
 255 static int read_index(struct iowarrior *dev)
 256 {
 257         int intr_idx, read_idx;
 258
 259         read_idx = atomic_read(&dev->read_idx);
 260         intr_idx = atomic_read(&dev->intr_idx);
 261
 262         return (read_idx == intr_idx ? -1 : read_idx);
 263 }
 264
 265 /**
 266  *  iowarrior_read
 267  */
 268 static ssize_t iowarrior_read(struct file *file, char __user *buffer,
 269                               size_t count, loff_t *ppos)
 270 {
 271         struct iowarrior *dev;
 272         int read_idx;
 273         int offset;
 274
 275         dev = file->private_data;
 276
 277         /* verify that the device wasn't unplugged */
 278         if (!dev || !dev->present)
 279                 return -ENODEV;
 280
 281         dev_dbg(&dev->interface->dev, "minor %d, count = %zd\n",
 282                 dev->minor, count);
 283
 284         /* read count must be packet size (+ time stamp) */
 285         if ((count != dev->report_size)
 286             && (count != (dev->report_size + 1)))
 287                 return -EINVAL;
 288
 289         /* repeat until no buffer overrun in callback handler occur */
 290         do {
 291                 atomic_set(&dev->overflow_flag, 0);
 292                 if ((read_idx = read_index(dev)) == -1) {
 293                         /* queue empty */
 294                         if (file->f_flags & O_NONBLOCK)
 295                                 return -EAGAIN;
 296                         else {
 297                                 //next line will return when there is either new data, or the device is unplugged
 298                                 int r = wait_event_interruptible(dev->read_wait,
 299                                                                  (!dev->present
 300                                                                   || (read_idx =
 301                                                                       read_index
 302                                                                       (dev)) !=
 303                                                                   -1));
 304                                 if (r) {
 305                                         //we were interrupted by a signal
 306                                         return -ERESTART;
 307                                 }
 308                                 if (!dev->present) {
 309                                         //The device was unplugged
 310                                         return -ENODEV;
 311                                 }
 312                                 if (read_idx == -1) {
 313                                         // Can this happen ???
 314                                         return 0;
 315                                 }
 316                         }
 317                 }
 318
 319                 offset = read_idx * (dev->report_size + 1);
 320                 if (copy_to_user(buffer, dev->read_queue + offset, count)) {
 321                         return -EFAULT;
 322                 }
 323         } while (atomic_read(&dev->overflow_flag));
 324
 325         read_idx = ++read_idx == MAX_INTERRUPT_BUFFER ? 0 : read_idx;
 326         atomic_set(&dev->read_idx, read_idx);
 327         return count;
 328 }
 329
 330 /*
 331  * iowarrior_write
 332  */
 333 static ssize_t iowarrior_write(struct file *file,
 334                                const char __user *user_buffer,
 335                                size_t count, loff_t *ppos)
 336 {
 337         struct iowarrior *dev;
 338         int retval = 0;
 339         char *buf = NULL;       /* for IOW24 and IOW56 we need a buffer */
 340         struct urb *int_out_urb = NULL;
 341
 342         dev = file->private_data;
 343
 344         mutex_lock(&dev->mutex);
 345         /* verify that the device wasn't unplugged */
 346         if (!dev->present) {
 347                 retval = -ENODEV;
 348                 goto exit;
 349         }
 350         dev_dbg(&dev->interface->dev, "minor %d, count = %zd\n",
 351                 dev->minor, count);
 352         /* if count is 0 we're already done */
 353         if (count == 0) {
 354                 retval = 0;
 355                 goto exit;
 356         }
 357         /* We only accept full reports */
 358         if (count != dev->report_size) {
 359                 retval = -EINVAL;
 360                 goto exit;
 361         }
 362         switch (dev->product_id) {
 363         case USB_DEVICE_ID_CODEMERCS_IOW24:
 364         case USB_DEVICE_ID_CODEMERCS_IOWPV1:
 365         case USB_DEVICE_ID_CODEMERCS_IOWPV2:
 366         case USB_DEVICE_ID_CODEMERCS_IOW40:
 367                 /* IOW24 and IOW40 use a synchronous call */
 368                 buf = memdup_user(user_buffer, count);
 369                 if (IS_ERR(buf)) {
 370                         retval = PTR_ERR(buf);
 371                         goto exit;
 372                 }
 373                 retval = usb_set_report(dev->interface, 2, 0, buf, count);
 374                 kfree(buf);
 375                 goto exit;
 376                 break;
 377         case USB_DEVICE_ID_CODEMERCS_IOW56:
 378                 /* The IOW56 uses asynchronous IO and more urbs */
 379                 if (atomic_read(&dev->write_busy) == MAX_WRITES_IN_FLIGHT) {
 380                         /* Wait until we are below the limit for submitted urbs */
 381                         if (file->f_flags & O_NONBLOCK) {
 382                                 retval = -EAGAIN;
 383                                 goto exit;
 384                         } else {
 385                                 retval = wait_event_interruptible(dev->write_wait,
 386                                                                   (!dev->present || (atomic_read (&dev-> write_busy) < MAX_WRITES_IN_FLIGHT)));
 387                                 if (retval) {
 388                                         /* we were interrupted by a signal */
 389                                         retval = -ERESTART;
 390                                         goto exit;
 391                                 }
 392                                 if (!dev->present) {
 393                                         /* The device was unplugged */
 394                                         retval = -ENODEV;
 395                                         goto exit;
 396                                 }
 397                                 if (!dev->opened) {
 398                                         /* We were closed while waiting for an URB */
 399                                         retval = -ENODEV;
 400                                         goto exit;
 401                                 }
 402                         }
 403                 }
 404                 atomic_inc(&dev->write_busy);
 405                 int_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 406                 if (!int_out_urb) {
 407                         retval = -ENOMEM;
 408                         goto error_no_urb;
 409                 }
 410                 buf = usb_alloc_coherent(dev->udev, dev->report_size,
 411                                          GFP_KERNEL, &int_out_urb->transfer_dma);
 412                 if (!buf) {
 413                         retval = -ENOMEM;
 414                         dev_dbg(&dev->interface->dev,
 415                                 "Unable to allocate buffer\n");
 416                         goto error_no_buffer;
 417                 }
 418                 usb_fill_int_urb(int_out_urb, dev->udev,
 419                                  usb_sndintpipe(dev->udev,
 420                                                 dev->int_out_endpoint->bEndpointAddress),
 421                                  buf, dev->report_size,
 422                                  iowarrior_write_callback, dev,
 423                                  dev->int_out_endpoint->bInterval);
 424                 int_out_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 425                 if (copy_from_user(buf, user_buffer, count)) {
 426                         retval = -EFAULT;
 427                         goto error;
 428                 }
 429                 usb_anchor_urb(int_out_urb, &dev->submitted);
 430                 retval = usb_submit_urb(int_out_urb, GFP_KERNEL);
 431                 if (retval) {
 432                         dev_dbg(&dev->interface->dev,
 433                                 "submit error %d for urb nr.%d\n",
 434                                 retval, atomic_read(&dev->write_busy));
 435                         usb_unanchor_urb(int_out_urb);
 436                         goto error;
 437                 }
 438                 /* submit was ok */
 439                 retval = count;
 440                 usb_free_urb(int_out_urb);
 441                 goto exit;
 442                 break;
 443         default:
 444                 /* what do we have here ? An unsupported Product-ID ? */
 445                 dev_err(&dev->interface->dev, "%s - not supported for product=0x%x\n",
 446                         __func__, dev->product_id);
 447                 retval = -EFAULT;
 448                 goto exit;
 449                 break;
 450         }
 451 error:
 452         usb_free_coherent(dev->udev, dev->report_size, buf,
 453                           int_out_urb->transfer_dma);
 454 error_no_buffer:
 455         usb_free_urb(int_out_urb);
 456 error_no_urb:
 457         atomic_dec(&dev->write_busy);
 458         wake_up_interruptible(&dev->write_wait);
 459 exit:
 460         mutex_unlock(&dev->mutex);
 461         return retval;
 462 }
 463
 464 /**
 465  *      iowarrior_ioctl
 466  */
 467 static long iowarrior_ioctl(struct file *file, unsigned int cmd,
 468                                                         unsigned long arg)
 469 {
 470         struct iowarrior *dev = NULL;
 471         __u8 *buffer;
 472         __u8 __user *user_buffer;
 473         int retval;
 474         int io_res;             /* checks for bytes read/written and copy_to/from_user results */
 475
 476         dev = file->private_data;
 477         if (!dev)
 478                 return -ENODEV;
 479
 480         buffer = kzalloc(dev->report_size, GFP_KERNEL);
 481         if (!buffer)
 482                 return -ENOMEM;
 483
 484         /* lock this object */
 485         mutex_lock(&iowarrior_mutex);
 486         mutex_lock(&dev->mutex);
 487
 488         /* verify that the device wasn't unplugged */
 489         if (!dev->present) {
 490                 retval = -ENODEV;
 491                 goto error_out;
 492         }
 493
 494         dev_dbg(&dev->interface->dev, "minor %d, cmd 0x%.4x, arg %ld\n",
 495                 dev->minor, cmd, arg);
 496
 497         retval = 0;
 498         io_res = 0;
 499         switch (cmd) {
 500         case IOW_WRITE:
 501                 if (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW24 ||
 502                     dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV1 ||
 503                     dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV2 ||
 504                     dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW40) {
 505                         user_buffer = (__u8 __user *)arg;
 506                         io_res = copy_from_user(buffer, user_buffer,
 507                                                 dev->report_size);
 508                         if (io_res) {
 509                                 retval = -EFAULT;
 510                         } else {
 511                                 io_res = usb_set_report(dev->interface, 2, 0,
 512                                                         buffer,
 513                                                         dev->report_size);
 514                                 if (io_res < 0)
 515                                         retval = io_res;
 516                         }
 517                 } else {
 518                         retval = -EINVAL;
 519                         dev_err(&dev->interface->dev,
 520                                 "ioctl 'IOW_WRITE' is not supported for product=0x%x.\n",
 521                                 dev->product_id);
 522                 }
 523                 break;
 524         case IOW_READ:
 525                 user_buffer = (__u8 __user *)arg;
 526                 io_res = usb_get_report(dev->udev,
 527                                         dev->interface->cur_altsetting, 1, 0,
 528                                         buffer, dev->report_size);
 529                 if (io_res < 0)
 530                         retval = io_res;
 531                 else {
 532                         io_res = copy_to_user(user_buffer, buffer, dev->report_size);
 533                         if (io_res)
 534                                 retval = -EFAULT;
 535                 }
 536                 break;
 537         case IOW_GETINFO:
 538                 {
 539                         /* Report available information for the device */
 540                         struct iowarrior_info info;
 541                         /* needed for power consumption */
 542                         struct usb_config_descriptor *cfg_descriptor = &dev->udev->actconfig->desc;
 543
 544                         memset(&info, 0, sizeof(info));
 545                         /* directly from the descriptor */
 546                         info.vendor = le16_to_cpu(dev->udev->descriptor.idVendor);
 547                         info.product = dev->product_id;
 548                         info.revision = le16_to_cpu(dev->udev->descriptor.bcdDevice);
 549
 550                         /* 0==UNKNOWN, 1==LOW(usb1.1) ,2=FULL(usb1.1), 3=HIGH(usb2.0) */
 551                         info.speed = dev->udev->speed;
 552                         info.if_num = dev->interface->cur_altsetting->desc.bInterfaceNumber;
 553                         info.report_size = dev->report_size;
 554
 555                         /* serial number string has been read earlier 8 chars or empty string */
 556                         memcpy(info.serial, dev->chip_serial,
 557                                sizeof(dev->chip_serial));
 558                         if (cfg_descriptor == NULL) {
 559                                 info.power = -1;        /* no information available */
 560                         } else {
 561                                 /* the MaxPower is stored in units of 2mA to make it fit into a byte-value */
 562                                 info.power = cfg_descriptor->bMaxPower * 2;
 563                         }
 564                         io_res = copy_to_user((struct iowarrior_info __user *)arg, &info,
 565                                          sizeof(struct iowarrior_info));
 566                         if (io_res)
 567                                 retval = -EFAULT;
 568                         break;
 569                 }
 570         default:
 571                 /* return that we did not understand this ioctl call */
 572                 retval = -ENOTTY;
 573                 break;
 574         }
 575 error_out:
 576         /* unlock the device */
 577         mutex_unlock(&dev->mutex);
 578         mutex_unlock(&iowarrior_mutex);
 579         kfree(buffer);
 580         return retval;
 581 }
 582
 583 /**
 584  *      iowarrior_open
 585  */
 586 static int iowarrior_open(struct inode *inode, struct file *file)
 587 {
 588         struct iowarrior *dev = NULL;
 589         struct usb_interface *interface;
 590         int subminor;
 591         int retval = 0;
 592
 593         mutex_lock(&iowarrior_mutex);
 594         subminor = iminor(inode);
 595
 596         interface = usb_find_interface(&iowarrior_driver, subminor);
 597         if (!interface) {
 598                 mutex_unlock(&iowarrior_mutex);
 599                 printk(KERN_ERR "%s - error, can't find device for minor %d\n",
 600                        __func__, subminor);
 601                 return -ENODEV;
 602         }
 603
 604         mutex_lock(&iowarrior_open_disc_lock);
 605         dev = usb_get_intfdata(interface);
 606         if (!dev) {
 607                 mutex_unlock(&iowarrior_open_disc_lock);
 608                 mutex_unlock(&iowarrior_mutex);
 609                 return -ENODEV;
 610         }
 611
 612         mutex_lock(&dev->mutex);
 613         mutex_unlock(&iowarrior_open_disc_lock);
 614
 615         /* Only one process can open each device, no sharing. */
 616         if (dev->opened) {
 617                 retval = -EBUSY;
 618                 goto out;
 619         }
 620
 621         /* setup interrupt handler for receiving values */
 622         if ((retval = usb_submit_urb(dev->int_in_urb, GFP_KERNEL)) < 0) {
 623                 dev_err(&interface->dev, "Error %d while submitting URB\n", retval);
 624                 retval = -EFAULT;
 625                 goto out;
 626         }
 627         /* increment our usage count for the driver */
 628         ++dev->opened;
 629         /* save our object in the file's private structure */
 630         file->private_data = dev;
 631         retval = 0;
 632
 633 out:
 634         mutex_unlock(&dev->mutex);
 635         mutex_unlock(&iowarrior_mutex);
 636         return retval;
 637 }
 638
 639 /**
 640  *      iowarrior_release
 641  */
 642 static int iowarrior_release(struct inode *inode, struct file *file)
 643 {
 644         struct iowarrior *dev;
 645         int retval = 0;
 646
 647         dev = file->private_data;
 648         if (!dev)
 649                 return -ENODEV;
 650
 651         dev_dbg(&dev->interface->dev, "minor %d\n", dev->minor);
 652
 653         /* lock our device */
 654         mutex_lock(&dev->mutex);
 655
 656         if (dev->opened <= 0) {
 657                 retval = -ENODEV;       /* close called more than once */
 658                 mutex_unlock(&dev->mutex);
 659         } else {
 660                 dev->opened = 0;        /* we're closing now */
 661                 retval = 0;
 662                 if (dev->present) {
 663                         /*
 664                            The device is still connected so we only shutdown
 665                            pending read-/write-ops.
 666                          */
 667                         usb_kill_urb(dev->int_in_urb);
 668                         wake_up_interruptible(&dev->read_wait);
 669                         wake_up_interruptible(&dev->write_wait);
 670                         mutex_unlock(&dev->mutex);
 671                 } else {
 672                         /* The device was unplugged, cleanup resources */
 673                         mutex_unlock(&dev->mutex);
 674                         iowarrior_delete(dev);
 675                 }
 676         }
 677         return retval;
 678 }
 679
 680 static __poll_t iowarrior_poll(struct file *file, poll_table * wait)
 681 {
 682         struct iowarrior *dev = file->private_data;
 683         __poll_t mask = 0;
 684
 685         if (!dev->present)
 686                 return EPOLLERR | EPOLLHUP;
 687
 688         poll_wait(file, &dev->read_wait, wait);
 689         poll_wait(file, &dev->write_wait, wait);
 690
 691         if (!dev->present)
 692                 return EPOLLERR | EPOLLHUP;
 693
 694         if (read_index(dev) != -1)
 695                 mask |= EPOLLIN | EPOLLRDNORM;
 696
 697         if (atomic_read(&dev->write_busy) < MAX_WRITES_IN_FLIGHT)
 698                 mask |= EPOLLOUT | EPOLLWRNORM;
 699         return mask;
 700 }
 701
 702 /*
 703  * File operations needed when we register this driver.
 704  * This assumes that this driver NEEDS file operations,
 705  * of course, which means that the driver is expected
 706  * to have a node in the /dev directory. If the USB
 707  * device were for a network interface then the driver
 708  * would use "struct net_driver" instead, and a serial
 709  * device would use "struct tty_driver".
 710  */
 711 static const struct file_operations iowarrior_fops = {
 712         .owner = THIS_MODULE,
 713         .write = iowarrior_write,
 714         .read = iowarrior_read,
 715         .unlocked_ioctl = iowarrior_ioctl,
 716         .open = iowarrior_open,
 717         .release = iowarrior_release,
 718         .poll = iowarrior_poll,
 719         .llseek = noop_llseek,
 720 };
 721
 722 static char *iowarrior_devnode(struct device *dev, umode_t *mode)
 723 {
 724         return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
 725 }
 726
 727 /*
 728  * usb class driver info in order to get a minor number from the usb core,
 729  * and to have the device registered with devfs and the driver core
 730  */
 731 static struct usb_class_driver iowarrior_class = {
 732         .name = "iowarrior%d",
 733         .devnode = iowarrior_devnode,
 734         .fops = &iowarrior_fops,
 735         .minor_base = IOWARRIOR_MINOR_BASE,
 736 };
 737
 738 /*---------------------------------*/
 739 /*  probe and disconnect functions */
 740 /*---------------------------------*/
 741 /**
 742  *      iowarrior_probe
 743  *
 744  *      Called by the usb core when a new device is connected that it thinks
 745  *      this driver might be interested in.
 746  */
 747 static int iowarrior_probe(struct usb_interface *interface,
 748                            const struct usb_device_id *id)
 749 {
 750         struct usb_device *udev = interface_to_usbdev(interface);
 751         struct iowarrior *dev = NULL;
 752         struct usb_host_interface *iface_desc;
 753         int retval = -ENOMEM;
 754         int res;
 755
 756         /* allocate memory for our device state and initialize it */
 757         dev = kzalloc(sizeof(struct iowarrior), GFP_KERNEL);
 758         if (!dev)
 759                 return retval;
 760
 761         mutex_init(&dev->mutex);
 762
 763         atomic_set(&dev->intr_idx, 0);
 764         atomic_set(&dev->read_idx, 0);
 765         atomic_set(&dev->overflow_flag, 0);
 766         init_waitqueue_head(&dev->read_wait);
 767         atomic_set(&dev->write_busy, 0);
 768         init_waitqueue_head(&dev->write_wait);
 769
 770         dev->udev = udev;
 771         dev->interface = usb_get_intf(interface);
 772
 773         iface_desc = interface->cur_altsetting;
 774         dev->product_id = le16_to_cpu(udev->descriptor.idProduct);
 775
 776         init_usb_anchor(&dev->submitted);
 777
 778         res = usb_find_last_int_in_endpoint(iface_desc, &dev->int_in_endpoint);
 779         if (res) {
 780                 dev_err(&interface->dev, "no interrupt-in endpoint found\n");
 781                 retval = res;
 782                 goto error;
 783         }
 784
 785         if (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW56) {
 786                 res = usb_find_last_int_out_endpoint(iface_desc,
 787                                 &dev->int_out_endpoint);
 788                 if (res) {
 789                         dev_err(&interface->dev, "no interrupt-out endpoint found\n");
 790                         retval = res;
 791                         goto error;
 792                 }
 793         }
 794
 795         /* we have to check the report_size often, so remember it in the endianness suitable for our machine */
 796         dev->report_size = usb_endpoint_maxp(dev->int_in_endpoint);
 797         if ((dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) &&
 798             (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW56))
 799                 /* IOWarrior56 has wMaxPacketSize different from report size */
 800                 dev->report_size = 7;
 801
 802         /* create the urb and buffer for reading */
 803         dev->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 804         if (!dev->int_in_urb)
 805                 goto error;
 806         dev->int_in_buffer = kmalloc(dev->report_size, GFP_KERNEL);
 807         if (!dev->int_in_buffer)
 808                 goto error;
 809         usb_fill_int_urb(dev->int_in_urb, dev->udev,
 810                          usb_rcvintpipe(dev->udev,
 811                                         dev->int_in_endpoint->bEndpointAddress),
 812                          dev->int_in_buffer, dev->report_size,
 813                          iowarrior_callback, dev,
 814                          dev->int_in_endpoint->bInterval);
 815         /* create an internal buffer for interrupt data from the device */
 816         dev->read_queue =
 817             kmalloc_array(dev->report_size + 1, MAX_INTERRUPT_BUFFER,
 818                           GFP_KERNEL);
 819         if (!dev->read_queue)
 820                 goto error;
 821         /* Get the serial-number of the chip */
 822         memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
 823         usb_string(udev, udev->descriptor.iSerialNumber, dev->chip_serial,
 824                    sizeof(dev->chip_serial));
 825         if (strlen(dev->chip_serial) != 8)
 826                 memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
 827
 828         /* Set the idle timeout to 0, if this is interface 0 */
 829         if (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) {
 830             usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
 831                             0x0A,
 832                             USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0,
 833                             0, NULL, 0, USB_CTRL_SET_TIMEOUT);
 834         }
 835         /* allow device read and ioctl */
 836         dev->present = 1;
 837
 838         /* we can register the device now, as it is ready */
 839         usb_set_intfdata(interface, dev);
 840
 841         retval = usb_register_dev(interface, &iowarrior_class);
 842         if (retval) {
 843                 /* something prevented us from registering this driver */
 844                 dev_err(&interface->dev, "Not able to get a minor for this device.\n");
 845                 usb_set_intfdata(interface, NULL);
 846                 goto error;
 847         }
 848
 849         dev->minor = interface->minor;
 850
 851         /* let the user know what node this device is now attached to */
 852         dev_info(&interface->dev, "IOWarrior product=0x%x, serial=%s interface=%d "
 853                  "now attached to iowarrior%d\n", dev->product_id, dev->chip_serial,
 854                  iface_desc->desc.bInterfaceNumber, dev->minor - IOWARRIOR_MINOR_BASE);
 855         return retval;
 856
 857 error:
 858         iowarrior_delete(dev);
 859         return retval;
 860 }
 861
 862 /**
 863  *      iowarrior_disconnect
 864  *
 865  *      Called by the usb core when the device is removed from the system.
 866  */
 867 static void iowarrior_disconnect(struct usb_interface *interface)
 868 {
 869         struct iowarrior *dev;
 870         int minor;
 871
 872         dev = usb_get_intfdata(interface);
 873         mutex_lock(&iowarrior_open_disc_lock);
 874         usb_set_intfdata(interface, NULL);
 875
 876         minor = dev->minor;
 877         mutex_unlock(&iowarrior_open_disc_lock);
 878         /* give back our minor - this will call close() locks need to be dropped at this point*/
 879
 880         usb_deregister_dev(interface, &iowarrior_class);
 881
 882         mutex_lock(&dev->mutex);
 883
 884         /* prevent device read, write and ioctl */
 885         dev->present = 0;
 886
 887         if (dev->opened) {
 888                 /* There is a process that holds a filedescriptor to the device ,
 889                    so we only shutdown read-/write-ops going on.
 890                    Deleting the device is postponed until close() was called.
 891                  */
 892                 usb_kill_urb(dev->int_in_urb);
 893                 usb_kill_anchored_urbs(&dev->submitted);
 894                 wake_up_interruptible(&dev->read_wait);
 895                 wake_up_interruptible(&dev->write_wait);
 896                 mutex_unlock(&dev->mutex);
 897         } else {
 898                 /* no process is using the device, cleanup now */
 899                 mutex_unlock(&dev->mutex);
 900                 iowarrior_delete(dev);
 901         }
 902
 903         dev_info(&interface->dev, "I/O-Warror #%d now disconnected\n",
 904                  minor - IOWARRIOR_MINOR_BASE);
 905 }
 906
 907 /* usb specific object needed to register this driver with the usb subsystem */
 908 static struct usb_driver iowarrior_driver = {
 909         .name = "iowarrior",
 910         .probe = iowarrior_probe,
 911         .disconnect = iowarrior_disconnect,
 912         .id_table = iowarrior_ids,
 913 };
 914
 915 module_usb_driver(iowarrior_driver);