drivers/usb/misc/ldusb.c

   1 /**
   2  * Generic USB driver for report based interrupt in/out devices
   3  * like LD Didactic's USB devices. LD Didactic's USB devices are
   4  * HID devices which do not use HID report definitons (they use
   5  * raw interrupt in and our reports only for communication).
   6  *
   7  * This driver uses a ring buffer for time critical reading of
   8  * interrupt in reports and provides read and write methods for
   9  * raw interrupt reports (similar to the Windows HID driver).
  10  * Devices based on the book USB COMPLETE by Jan Axelson may need
  11  * such a compatibility to the Windows HID driver.
  12  *
  13  * Copyright (C) 2005 Michael Hund <mhund@ld-didactic.de>
  14  *
  15  *      This program is free software; you can redistribute it and/or
  16  *      modify it under the terms of the GNU General Public License as
  17  *      published by the Free Software Foundation; either version 2 of
  18  *      the License, or (at your option) any later version.
  19  *
  20  * Derived from Lego USB Tower driver
  21  * Copyright (C) 2003 David Glance <advidgsf@sourceforge.net>
  22  *               2001-2004 Juergen Stuber <starblue@users.sourceforge.net>
  23  */
  24
  25 #include <linux/kernel.h>
  26 #include <linux/errno.h>
  27 #include <linux/slab.h>
  28 #include <linux/module.h>
  29 #include <linux/mutex.h>
  30
  31 #include <asm/uaccess.h>
  32 #include <linux/input.h>
  33 #include <linux/usb.h>
  34 #include <linux/poll.h>
  35
  36 /* Define these values to match your devices */
  37 #define USB_VENDOR_ID_LD                0x0f11  /* USB Vendor ID of LD Didactic GmbH */
  38 #define USB_DEVICE_ID_LD_CASSY          0x1000  /* USB Product ID of CASSY-S modules with 8 bytes endpoint size */
  39 #define USB_DEVICE_ID_LD_CASSY2         0x1001  /* USB Product ID of CASSY-S modules with 64 bytes endpoint size */
  40 #define USB_DEVICE_ID_LD_POCKETCASSY    0x1010  /* USB Product ID of Pocket-CASSY */
  41 #define USB_DEVICE_ID_LD_POCKETCASSY2   0x1011  /* USB Product ID of Pocket-CASSY 2 (reserved) */
  42 #define USB_DEVICE_ID_LD_MOBILECASSY    0x1020  /* USB Product ID of Mobile-CASSY */
  43 #define USB_DEVICE_ID_LD_MOBILECASSY2   0x1021  /* USB Product ID of Mobile-CASSY 2 (reserved) */
  44 #define USB_DEVICE_ID_LD_MICROCASSYVOLTAGE      0x1031  /* USB Product ID of Micro-CASSY Voltage */
  45 #define USB_DEVICE_ID_LD_MICROCASSYCURRENT      0x1032  /* USB Product ID of Micro-CASSY Current */
  46 #define USB_DEVICE_ID_LD_MICROCASSYTIME         0x1033  /* USB Product ID of Micro-CASSY Time (reserved) */
  47 #define USB_DEVICE_ID_LD_MICROCASSYTEMPERATURE  0x1035  /* USB Product ID of Micro-CASSY Temperature */
  48 #define USB_DEVICE_ID_LD_MICROCASSYPH           0x1038  /* USB Product ID of Micro-CASSY pH */
  49 #define USB_DEVICE_ID_LD_JWM            0x1080  /* USB Product ID of Joule and Wattmeter */
  50 #define USB_DEVICE_ID_LD_DMMP           0x1081  /* USB Product ID of Digital Multimeter P (reserved) */
  51 #define USB_DEVICE_ID_LD_UMIP           0x1090  /* USB Product ID of UMI P */
  52 #define USB_DEVICE_ID_LD_UMIC           0x10A0  /* USB Product ID of UMI C */
  53 #define USB_DEVICE_ID_LD_UMIB           0x10B0  /* USB Product ID of UMI B */
  54 #define USB_DEVICE_ID_LD_XRAY           0x1100  /* USB Product ID of X-Ray Apparatus 55481 */
  55 #define USB_DEVICE_ID_LD_XRAY2          0x1101  /* USB Product ID of X-Ray Apparatus 554800 */
  56 #define USB_DEVICE_ID_LD_XRAYCT         0x1110  /* USB Product ID of X-Ray Apparatus CT 554821*/
  57 #define USB_DEVICE_ID_LD_VIDEOCOM       0x1200  /* USB Product ID of VideoCom */
  58 #define USB_DEVICE_ID_LD_MOTOR          0x1210  /* USB Product ID of Motor (reserved) */
  59 #define USB_DEVICE_ID_LD_COM3LAB        0x2000  /* USB Product ID of COM3LAB */
  60 #define USB_DEVICE_ID_LD_TELEPORT       0x2010  /* USB Product ID of Terminal Adapter */
  61 #define USB_DEVICE_ID_LD_NETWORKANALYSER 0x2020 /* USB Product ID of Network Analyser */
  62 #define USB_DEVICE_ID_LD_POWERCONTROL   0x2030  /* USB Product ID of Converter Control Unit */
  63 #define USB_DEVICE_ID_LD_MACHINETEST    0x2040  /* USB Product ID of Machine Test System */
  64 #define USB_DEVICE_ID_LD_MOSTANALYSER   0x2050  /* USB Product ID of MOST Protocol Analyser */
  65 #define USB_DEVICE_ID_LD_MOSTANALYSER2  0x2051  /* USB Product ID of MOST Protocol Analyser 2 */
  66 #define USB_DEVICE_ID_LD_ABSESP         0x2060  /* USB Product ID of ABS ESP */
  67 #define USB_DEVICE_ID_LD_AUTODATABUS    0x2070  /* USB Product ID of Automotive Data Buses */
  68 #define USB_DEVICE_ID_LD_MCT            0x2080  /* USB Product ID of Microcontroller technique */
  69 #define USB_DEVICE_ID_LD_HYBRID         0x2090  /* USB Product ID of Automotive Hybrid */
  70 #define USB_DEVICE_ID_LD_HEATCONTROL    0x20A0  /* USB Product ID of Heat control */
  71
  72 #ifdef CONFIG_USB_DYNAMIC_MINORS
  73 #define USB_LD_MINOR_BASE       0
  74 #else
  75 #define USB_LD_MINOR_BASE       176
  76 #endif
  77
  78 /* table of devices that work with this driver */
  79 static const struct usb_device_id ld_usb_table[] = {
  80         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CASSY) },
  81         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CASSY2) },
  82         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POCKETCASSY) },
  83         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POCKETCASSY2) },
  84         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOBILECASSY) },
  85         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOBILECASSY2) },
  86         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYVOLTAGE) },
  87         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYCURRENT) },
  88         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYTIME) },
  89         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYTEMPERATURE) },
  90         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYPH) },
  91         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_JWM) },
  92         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_DMMP) },
  93         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIP) },
  94         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIC) },
  95         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIB) },
  96         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_XRAY) },
  97         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_XRAY2) },
  98         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_VIDEOCOM) },
  99         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOTOR) },
 100         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_COM3LAB) },
 101         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_TELEPORT) },
 102         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_NETWORKANALYSER) },
 103         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POWERCONTROL) },
 104         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MACHINETEST) },
 105         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOSTANALYSER) },
 106         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOSTANALYSER2) },
 107         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_ABSESP) },
 108         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_AUTODATABUS) },
 109         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MCT) },
 110         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_HYBRID) },
 111         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_HEATCONTROL) },
 112         { }                                     /* Terminating entry */
 113 };
 114 MODULE_DEVICE_TABLE(usb, ld_usb_table);
 115 MODULE_VERSION("V0.14");
 116 MODULE_AUTHOR("Michael Hund <mhund@ld-didactic.de>");
 117 MODULE_DESCRIPTION("LD USB Driver");
 118 MODULE_LICENSE("GPL");
 119 MODULE_SUPPORTED_DEVICE("LD USB Devices");
 120
 121 /* All interrupt in transfers are collected in a ring buffer to
 122  * avoid racing conditions and get better performance of the driver.
 123  */
 124 static int ring_buffer_size = 128;
 125 module_param(ring_buffer_size, int, 0);
 126 MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size in reports");
 127
 128 /* The write_buffer can contain more than one interrupt out transfer.
 129  */
 130 static int write_buffer_size = 10;
 131 module_param(write_buffer_size, int, 0);
 132 MODULE_PARM_DESC(write_buffer_size, "Write buffer size in reports");
 133
 134 /* As of kernel version 2.6.4 ehci-hcd uses an
 135  * "only one interrupt transfer per frame" shortcut
 136  * to simplify the scheduling of periodic transfers.
 137  * This conflicts with our standard 1ms intervals for in and out URBs.
 138  * We use default intervals of 2ms for in and 2ms for out transfers,
 139  * which should be fast enough.
 140  * Increase the interval to allow more devices that do interrupt transfers,
 141  * or set to 1 to use the standard interval from the endpoint descriptors.
 142  */
 143 static int min_interrupt_in_interval = 2;
 144 module_param(min_interrupt_in_interval, int, 0);
 145 MODULE_PARM_DESC(min_interrupt_in_interval, "Minimum interrupt in interval in ms");
 146
 147 static int min_interrupt_out_interval = 2;
 148 module_param(min_interrupt_out_interval, int, 0);
 149 MODULE_PARM_DESC(min_interrupt_out_interval, "Minimum interrupt out interval in ms");
 150
 151 /* Structure to hold all of our device specific stuff */
 152 struct ld_usb {
 153         struct mutex            mutex;          /* locks this structure */
 154         struct usb_interface*   intf;           /* save off the usb interface pointer */
 155
 156         int                     open_count;     /* number of times this port has been opened */
 157
 158         char*                   ring_buffer;
 159         unsigned int            ring_head;
 160         unsigned int            ring_tail;
 161
 162         wait_queue_head_t       read_wait;
 163         wait_queue_head_t       write_wait;
 164
 165         char*                   interrupt_in_buffer;
 166         struct usb_endpoint_descriptor* interrupt_in_endpoint;
 167         struct urb*             interrupt_in_urb;
 168         int                     interrupt_in_interval;
 169         size_t                  interrupt_in_endpoint_size;
 170         int                     interrupt_in_running;
 171         int                     interrupt_in_done;
 172         int                     buffer_overflow;
 173         spinlock_t              rbsl;
 174
 175         char*                   interrupt_out_buffer;
 176         struct usb_endpoint_descriptor* interrupt_out_endpoint;
 177         struct urb*             interrupt_out_urb;
 178         int                     interrupt_out_interval;
 179         size_t                  interrupt_out_endpoint_size;
 180         int                     interrupt_out_busy;
 181 };
 182
 183 static struct usb_driver ld_usb_driver;
 184
 185 /**
 186  *      ld_usb_abort_transfers
 187  *      aborts transfers and frees associated data structures
 188  */
 189 static void ld_usb_abort_transfers(struct ld_usb *dev)
 190 {
 191         /* shutdown transfer */
 192         if (dev->interrupt_in_running) {
 193                 dev->interrupt_in_running = 0;
 194                 if (dev->intf)
 195                         usb_kill_urb(dev->interrupt_in_urb);
 196         }
 197         if (dev->interrupt_out_busy)
 198                 if (dev->intf)
 199                         usb_kill_urb(dev->interrupt_out_urb);
 200 }
 201
 202 /**
 203  *      ld_usb_delete
 204  */
 205 static void ld_usb_delete(struct ld_usb *dev)
 206 {
 207         ld_usb_abort_transfers(dev);
 208
 209         /* free data structures */
 210         usb_free_urb(dev->interrupt_in_urb);
 211         usb_free_urb(dev->interrupt_out_urb);
 212         kfree(dev->ring_buffer);
 213         kfree(dev->interrupt_in_buffer);
 214         kfree(dev->interrupt_out_buffer);
 215         kfree(dev);
 216 }
 217
 218 /**
 219  *      ld_usb_interrupt_in_callback
 220  */
 221 static void ld_usb_interrupt_in_callback(struct urb *urb)
 222 {
 223         struct ld_usb *dev = urb->context;
 224         size_t *actual_buffer;
 225         unsigned int next_ring_head;
 226         int status = urb->status;
 227         int retval;
 228
 229         if (status) {
 230                 if (status == -ENOENT ||
 231                     status == -ECONNRESET ||
 232                     status == -ESHUTDOWN) {
 233                         goto exit;
 234                 } else {
 235                         dev_dbg(&dev->intf->dev,
 236                                 "%s: nonzero status received: %d\n", __func__,
 237                                 status);
 238                         spin_lock(&dev->rbsl);
 239                         goto resubmit; /* maybe we can recover */
 240                 }
 241         }
 242
 243         spin_lock(&dev->rbsl);
 244         if (urb->actual_length > 0) {
 245                 next_ring_head = (dev->ring_head+1) % ring_buffer_size;
 246                 if (next_ring_head != dev->ring_tail) {
 247                         actual_buffer = (size_t*)(dev->ring_buffer + dev->ring_head*(sizeof(size_t)+dev->interrupt_in_endpoint_size));
 248                         /* actual_buffer gets urb->actual_length + interrupt_in_buffer */
 249                         *actual_buffer = urb->actual_length;
 250                         memcpy(actual_buffer+1, dev->interrupt_in_buffer, urb->actual_length);
 251                         dev->ring_head = next_ring_head;
 252                         dev_dbg(&dev->intf->dev, "%s: received %d bytes\n",
 253                                 __func__, urb->actual_length);
 254                 } else {
 255                         dev_warn(&dev->intf->dev,
 256                                  "Ring buffer overflow, %d bytes dropped\n",
 257                                  urb->actual_length);
 258                         dev->buffer_overflow = 1;
 259                 }
 260         }
 261
 262 resubmit:
 263         /* resubmit if we're still running */
 264         if (dev->interrupt_in_running && !dev->buffer_overflow && dev->intf) {
 265                 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
 266                 if (retval) {
 267                         dev_err(&dev->intf->dev,
 268                                 "usb_submit_urb failed (%d)\n", retval);
 269                         dev->buffer_overflow = 1;
 270                 }
 271         }
 272         spin_unlock(&dev->rbsl);
 273 exit:
 274         dev->interrupt_in_done = 1;
 275         wake_up_interruptible(&dev->read_wait);
 276 }
 277
 278 /**
 279  *      ld_usb_interrupt_out_callback
 280  */
 281 static void ld_usb_interrupt_out_callback(struct urb *urb)
 282 {
 283         struct ld_usb *dev = urb->context;
 284         int status = urb->status;
 285
 286         /* sync/async unlink faults aren't errors */
 287         if (status && !(status == -ENOENT ||
 288                         status == -ECONNRESET ||
 289                         status == -ESHUTDOWN))
 290                 dev_dbg(&dev->intf->dev,
 291                         "%s - nonzero write interrupt status received: %d\n",
 292                         __func__, status);
 293
 294         dev->interrupt_out_busy = 0;
 295         wake_up_interruptible(&dev->write_wait);
 296 }
 297
 298 /**
 299  *      ld_usb_open
 300  */
 301 static int ld_usb_open(struct inode *inode, struct file *file)
 302 {
 303         struct ld_usb *dev;
 304         int subminor;
 305         int retval;
 306         struct usb_interface *interface;
 307
 308         nonseekable_open(inode, file);
 309         subminor = iminor(inode);
 310
 311         interface = usb_find_interface(&ld_usb_driver, subminor);
 312
 313         if (!interface) {
 314                 printk(KERN_ERR "%s - error, can't find device for minor %d\n",
 315                        __func__, subminor);
 316                 return -ENODEV;
 317         }
 318
 319         dev = usb_get_intfdata(interface);
 320
 321         if (!dev)
 322                 return -ENODEV;
 323
 324         /* lock this device */
 325         if (mutex_lock_interruptible(&dev->mutex))
 326                 return -ERESTARTSYS;
 327
 328         /* allow opening only once */
 329         if (dev->open_count) {
 330                 retval = -EBUSY;
 331                 goto unlock_exit;
 332         }
 333         dev->open_count = 1;
 334
 335         /* initialize in direction */
 336         dev->ring_head = 0;
 337         dev->ring_tail = 0;
 338         dev->buffer_overflow = 0;
 339         usb_fill_int_urb(dev->interrupt_in_urb,
 340                          interface_to_usbdev(interface),
 341                          usb_rcvintpipe(interface_to_usbdev(interface),
 342                                         dev->interrupt_in_endpoint->bEndpointAddress),
 343                          dev->interrupt_in_buffer,
 344                          dev->interrupt_in_endpoint_size,
 345                          ld_usb_interrupt_in_callback,
 346                          dev,
 347                          dev->interrupt_in_interval);
 348
 349         dev->interrupt_in_running = 1;
 350         dev->interrupt_in_done = 0;
 351
 352         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 353         if (retval) {
 354                 dev_err(&interface->dev, "Couldn't submit interrupt_in_urb %d\n", retval);
 355                 dev->interrupt_in_running = 0;
 356                 dev->open_count = 0;
 357                 goto unlock_exit;
 358         }
 359
 360         /* save device in the file's private structure */
 361         file->private_data = dev;
 362
 363 unlock_exit:
 364         mutex_unlock(&dev->mutex);
 365
 366         return retval;
 367 }
 368
 369 /**
 370  *      ld_usb_release
 371  */
 372 static int ld_usb_release(struct inode *inode, struct file *file)
 373 {
 374         struct ld_usb *dev;
 375         int retval = 0;
 376
 377         dev = file->private_data;
 378
 379         if (dev == NULL) {
 380                 retval = -ENODEV;
 381                 goto exit;
 382         }
 383
 384         if (mutex_lock_interruptible(&dev->mutex)) {
 385                 retval = -ERESTARTSYS;
 386                 goto exit;
 387         }
 388
 389         if (dev->open_count != 1) {
 390                 retval = -ENODEV;
 391                 goto unlock_exit;
 392         }
 393         if (dev->intf == NULL) {
 394                 /* the device was unplugged before the file was released */
 395                 mutex_unlock(&dev->mutex);
 396                 /* unlock here as ld_usb_delete frees dev */
 397                 ld_usb_delete(dev);
 398                 goto exit;
 399         }
 400
 401         /* wait until write transfer is finished */
 402         if (dev->interrupt_out_busy)
 403                 wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 404         ld_usb_abort_transfers(dev);
 405         dev->open_count = 0;
 406
 407 unlock_exit:
 408         mutex_unlock(&dev->mutex);
 409
 410 exit:
 411         return retval;
 412 }
 413
 414 /**
 415  *      ld_usb_poll
 416  */
 417 static unsigned int ld_usb_poll(struct file *file, poll_table *wait)
 418 {
 419         struct ld_usb *dev;
 420         unsigned int mask = 0;
 421
 422         dev = file->private_data;
 423
 424         if (!dev->intf)
 425                 return POLLERR | POLLHUP;
 426
 427         poll_wait(file, &dev->read_wait, wait);
 428         poll_wait(file, &dev->write_wait, wait);
 429
 430         if (dev->ring_head != dev->ring_tail)
 431                 mask |= POLLIN | POLLRDNORM;
 432         if (!dev->interrupt_out_busy)
 433                 mask |= POLLOUT | POLLWRNORM;
 434
 435         return mask;
 436 }
 437
 438 /**
 439  *      ld_usb_read
 440  */
 441 static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
 442                            loff_t *ppos)
 443 {
 444         struct ld_usb *dev;
 445         size_t *actual_buffer;
 446         size_t bytes_to_read;
 447         int retval = 0;
 448         int rv;
 449
 450         dev = file->private_data;
 451
 452         /* verify that we actually have some data to read */
 453         if (count == 0)
 454                 goto exit;
 455
 456         /* lock this object */
 457         if (mutex_lock_interruptible(&dev->mutex)) {
 458                 retval = -ERESTARTSYS;
 459                 goto exit;
 460         }
 461
 462         /* verify that the device wasn't unplugged */
 463         if (dev->intf == NULL) {
 464                 retval = -ENODEV;
 465                 printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
 466                 goto unlock_exit;
 467         }
 468
 469         /* wait for data */
 470         spin_lock_irq(&dev->rbsl);
 471         if (dev->ring_head == dev->ring_tail) {
 472                 dev->interrupt_in_done = 0;
 473                 spin_unlock_irq(&dev->rbsl);
 474                 if (file->f_flags & O_NONBLOCK) {
 475                         retval = -EAGAIN;
 476                         goto unlock_exit;
 477                 }
 478                 retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
 479                 if (retval < 0)
 480                         goto unlock_exit;
 481         } else {
 482                 spin_unlock_irq(&dev->rbsl);
 483         }
 484
 485         /* actual_buffer contains actual_length + interrupt_in_buffer */
 486         actual_buffer = (size_t*)(dev->ring_buffer + dev->ring_tail*(sizeof(size_t)+dev->interrupt_in_endpoint_size));
 487         bytes_to_read = min(count, *actual_buffer);
 488         if (bytes_to_read < *actual_buffer)
 489                 dev_warn(&dev->intf->dev, "Read buffer overflow, %zd bytes dropped\n",
 490                          *actual_buffer-bytes_to_read);
 491
 492         /* copy one interrupt_in_buffer from ring_buffer into userspace */
 493         if (copy_to_user(buffer, actual_buffer+1, bytes_to_read)) {
 494                 retval = -EFAULT;
 495                 goto unlock_exit;
 496         }
 497         dev->ring_tail = (dev->ring_tail+1) % ring_buffer_size;
 498
 499         retval = bytes_to_read;
 500
 501         spin_lock_irq(&dev->rbsl);
 502         if (dev->buffer_overflow) {
 503                 dev->buffer_overflow = 0;
 504                 spin_unlock_irq(&dev->rbsl);
 505                 rv = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 506                 if (rv < 0)
 507                         dev->buffer_overflow = 1;
 508         } else {
 509                 spin_unlock_irq(&dev->rbsl);
 510         }
 511
 512 unlock_exit:
 513         /* unlock the device */
 514         mutex_unlock(&dev->mutex);
 515
 516 exit:
 517         return retval;
 518 }
 519
 520 /**
 521  *      ld_usb_write
 522  */
 523 static ssize_t ld_usb_write(struct file *file, const char __user *buffer,
 524                             size_t count, loff_t *ppos)
 525 {
 526         struct ld_usb *dev;
 527         size_t bytes_to_write;
 528         int retval = 0;
 529
 530         dev = file->private_data;
 531
 532         /* verify that we actually have some data to write */
 533         if (count == 0)
 534                 goto exit;
 535
 536         /* lock this object */
 537         if (mutex_lock_interruptible(&dev->mutex)) {
 538                 retval = -ERESTARTSYS;
 539                 goto exit;
 540         }
 541
 542         /* verify that the device wasn't unplugged */
 543         if (dev->intf == NULL) {
 544                 retval = -ENODEV;
 545                 printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
 546                 goto unlock_exit;
 547         }
 548
 549         /* wait until previous transfer is finished */
 550         if (dev->interrupt_out_busy) {
 551                 if (file->f_flags & O_NONBLOCK) {
 552                         retval = -EAGAIN;
 553                         goto unlock_exit;
 554                 }
 555                 retval = wait_event_interruptible(dev->write_wait, !dev->interrupt_out_busy);
 556                 if (retval < 0) {
 557                         goto unlock_exit;
 558                 }
 559         }
 560
 561         /* write the data into interrupt_out_buffer from userspace */
 562         bytes_to_write = min(count, write_buffer_size*dev->interrupt_out_endpoint_size);
 563         if (bytes_to_write < count)
 564                 dev_warn(&dev->intf->dev, "Write buffer overflow, %zd bytes dropped\n",count-bytes_to_write);
 565         dev_dbg(&dev->intf->dev, "%s: count = %zd, bytes_to_write = %zd\n",
 566                 __func__, count, bytes_to_write);
 567
 568         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 569                 retval = -EFAULT;
 570                 goto unlock_exit;
 571         }
 572
 573         if (dev->interrupt_out_endpoint == NULL) {
 574                 /* try HID_REQ_SET_REPORT=9 on control_endpoint instead of interrupt_out_endpoint */
 575                 retval = usb_control_msg(interface_to_usbdev(dev->intf),
 576                                          usb_sndctrlpipe(interface_to_usbdev(dev->intf), 0),
 577                                          9,
 578                                          USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
 579                                          1 << 8, 0,
 580                                          dev->interrupt_out_buffer,
 581                                          bytes_to_write,
 582                                          USB_CTRL_SET_TIMEOUT * HZ);
 583                 if (retval < 0)
 584                         dev_err(&dev->intf->dev,
 585                                 "Couldn't submit HID_REQ_SET_REPORT %d\n",
 586                                 retval);
 587                 goto unlock_exit;
 588         }
 589
 590         /* send off the urb */
 591         usb_fill_int_urb(dev->interrupt_out_urb,
 592                          interface_to_usbdev(dev->intf),
 593                          usb_sndintpipe(interface_to_usbdev(dev->intf),
 594                                         dev->interrupt_out_endpoint->bEndpointAddress),
 595                          dev->interrupt_out_buffer,
 596                          bytes_to_write,
 597                          ld_usb_interrupt_out_callback,
 598                          dev,
 599                          dev->interrupt_out_interval);
 600
 601         dev->interrupt_out_busy = 1;
 602         wmb();
 603
 604         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 605         if (retval) {
 606                 dev->interrupt_out_busy = 0;
 607                 dev_err(&dev->intf->dev,
 608                         "Couldn't submit interrupt_out_urb %d\n", retval);
 609                 goto unlock_exit;
 610         }
 611         retval = bytes_to_write;
 612
 613 unlock_exit:
 614         /* unlock the device */
 615         mutex_unlock(&dev->mutex);
 616
 617 exit:
 618         return retval;
 619 }
 620
 621 /* file operations needed when we register this driver */
 622 static const struct file_operations ld_usb_fops = {
 623         .owner =        THIS_MODULE,
 624         .read  =        ld_usb_read,
 625         .write =        ld_usb_write,
 626         .open =         ld_usb_open,
 627         .release =      ld_usb_release,
 628         .poll =         ld_usb_poll,
 629         .llseek =       no_llseek,
 630 };
 631
 632 /*
 633  * usb class driver info in order to get a minor number from the usb core,
 634  * and to have the device registered with the driver core
 635  */
 636 static struct usb_class_driver ld_usb_class = {
 637         .name =         "ldusb%d",
 638         .fops =         &ld_usb_fops,
 639         .minor_base =   USB_LD_MINOR_BASE,
 640 };
 641
 642 /**
 643  *      ld_usb_probe
 644  *
 645  *      Called by the usb core when a new device is connected that it thinks
 646  *      this driver might be interested in.
 647  */
 648 static int ld_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
 649 {
 650         struct usb_device *udev = interface_to_usbdev(intf);
 651         struct ld_usb *dev = NULL;
 652         struct usb_host_interface *iface_desc;
 653         struct usb_endpoint_descriptor *endpoint;
 654         char *buffer;
 655         int i;
 656         int retval = -ENOMEM;
 657
 658         /* allocate memory for our device state and initialize it */
 659
 660         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 661         if (!dev)
 662                 goto exit;
 663         mutex_init(&dev->mutex);
 664         spin_lock_init(&dev->rbsl);
 665         dev->intf = intf;
 666         init_waitqueue_head(&dev->read_wait);
 667         init_waitqueue_head(&dev->write_wait);
 668
 669         /* workaround for early firmware versions on fast computers */
 670         if ((le16_to_cpu(udev->descriptor.idVendor) == USB_VENDOR_ID_LD) &&
 671             ((le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_CASSY) ||
 672              (le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_COM3LAB)) &&
 673             (le16_to_cpu(udev->descriptor.bcdDevice) <= 0x103)) {
 674                 buffer = kmalloc(256, GFP_KERNEL);
 675                 if (!buffer)
 676                         goto error;
 677                 /* usb_string makes SETUP+STALL to leave always ControlReadLoop */
 678                 usb_string(udev, 255, buffer, 256);
 679                 kfree(buffer);
 680         }
 681
 682         iface_desc = intf->cur_altsetting;
 683
 684         /* set up the endpoint information */
 685         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 686                 endpoint = &iface_desc->endpoint[i].desc;
 687
 688                 if (usb_endpoint_is_int_in(endpoint))
 689                         dev->interrupt_in_endpoint = endpoint;
 690
 691                 if (usb_endpoint_is_int_out(endpoint))
 692                         dev->interrupt_out_endpoint = endpoint;
 693         }
 694         if (dev->interrupt_in_endpoint == NULL) {
 695                 dev_err(&intf->dev, "Interrupt in endpoint not found\n");
 696                 goto error;
 697         }
 698         if (dev->interrupt_out_endpoint == NULL)
 699                 dev_warn(&intf->dev, "Interrupt out endpoint not found (using control endpoint instead)\n");
 700
 701         dev->interrupt_in_endpoint_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
 702         dev->ring_buffer = kmalloc(ring_buffer_size*(sizeof(size_t)+dev->interrupt_in_endpoint_size), GFP_KERNEL);
 703         if (!dev->ring_buffer)
 704                 goto error;
 705         dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 706         if (!dev->interrupt_in_buffer)
 707                 goto error;
 708         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 709         if (!dev->interrupt_in_urb)
 710                 goto error;
 711         dev->interrupt_out_endpoint_size = dev->interrupt_out_endpoint ? usb_endpoint_maxp(dev->interrupt_out_endpoint) :
 712                                                                          udev->descriptor.bMaxPacketSize0;
 713         dev->interrupt_out_buffer = kmalloc(write_buffer_size*dev->interrupt_out_endpoint_size, GFP_KERNEL);
 714         if (!dev->interrupt_out_buffer)
 715                 goto error;
 716         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 717         if (!dev->interrupt_out_urb)
 718                 goto error;
 719         dev->interrupt_in_interval = min_interrupt_in_interval > dev->interrupt_in_endpoint->bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 720         if (dev->interrupt_out_endpoint)
 721                 dev->interrupt_out_interval = min_interrupt_out_interval > dev->interrupt_out_endpoint->bInterval ? min_interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 722
 723         /* we can register the device now, as it is ready */
 724         usb_set_intfdata(intf, dev);
 725
 726         retval = usb_register_dev(intf, &ld_usb_class);
 727         if (retval) {
 728                 /* something prevented us from registering this driver */
 729                 dev_err(&intf->dev, "Not able to get a minor for this device.\n");
 730                 usb_set_intfdata(intf, NULL);
 731                 goto error;
 732         }
 733
 734         /* let the user know what node this device is now attached to */
 735         dev_info(&intf->dev, "LD USB Device #%d now attached to major %d minor %d\n",
 736                 (intf->minor - USB_LD_MINOR_BASE), USB_MAJOR, intf->minor);
 737
 738 exit:
 739         return retval;
 740
 741 error:
 742         ld_usb_delete(dev);
 743
 744         return retval;
 745 }
 746
 747 /**
 748  *      ld_usb_disconnect
 749  *
 750  *      Called by the usb core when the device is removed from the system.
 751  */
 752 static void ld_usb_disconnect(struct usb_interface *intf)
 753 {
 754         struct ld_usb *dev;
 755         int minor;
 756
 757         dev = usb_get_intfdata(intf);
 758         usb_set_intfdata(intf, NULL);
 759
 760         minor = intf->minor;
 761
 762         /* give back our minor */
 763         usb_deregister_dev(intf, &ld_usb_class);
 764
 765         mutex_lock(&dev->mutex);
 766
 767         /* if the device is not opened, then we clean up right now */
 768         if (!dev->open_count) {
 769                 mutex_unlock(&dev->mutex);
 770                 ld_usb_delete(dev);
 771         } else {
 772                 dev->intf = NULL;
 773                 /* wake up pollers */
 774                 wake_up_interruptible_all(&dev->read_wait);
 775                 wake_up_interruptible_all(&dev->write_wait);
 776                 mutex_unlock(&dev->mutex);
 777         }
 778
 779         dev_info(&intf->dev, "LD USB Device #%d now disconnected\n",
 780                  (minor - USB_LD_MINOR_BASE));
 781 }
 782
 783 /* usb specific object needed to register this driver with the usb subsystem */
 784 static struct usb_driver ld_usb_driver = {
 785         .name =         "ldusb",
 786         .probe =        ld_usb_probe,
 787         .disconnect =   ld_usb_disconnect,
 788         .id_table =     ld_usb_table,
 789 };
 790
 791 module_usb_driver(ld_usb_driver);
 792