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