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 <linux/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_POWERANALYSERCASSY     0x1040  /* USB Product ID of Power Analyser CASSY */
  50 #define USB_DEVICE_ID_LD_CONVERTERCONTROLLERCASSY       0x1042  /* USB Product ID of Converter Controller CASSY */
  51 #define USB_DEVICE_ID_LD_MACHINETESTCASSY       0x1043  /* USB Product ID of Machine Test CASSY */
  52 #define USB_DEVICE_ID_LD_JWM            0x1080  /* USB Product ID of Joule and Wattmeter */
  53 #define USB_DEVICE_ID_LD_DMMP           0x1081  /* USB Product ID of Digital Multimeter P (reserved) */
  54 #define USB_DEVICE_ID_LD_UMIP           0x1090  /* USB Product ID of UMI P */
  55 #define USB_DEVICE_ID_LD_UMIC           0x10A0  /* USB Product ID of UMI C */
  56 #define USB_DEVICE_ID_LD_UMIB           0x10B0  /* USB Product ID of UMI B */
  57 #define USB_DEVICE_ID_LD_XRAY           0x1100  /* USB Product ID of X-Ray Apparatus 55481 */
  58 #define USB_DEVICE_ID_LD_XRAY2          0x1101  /* USB Product ID of X-Ray Apparatus 554800 */
  59 #define USB_DEVICE_ID_LD_XRAYCT         0x1110  /* USB Product ID of X-Ray Apparatus CT 554821*/
  60 #define USB_DEVICE_ID_LD_VIDEOCOM       0x1200  /* USB Product ID of VideoCom */
  61 #define USB_DEVICE_ID_LD_MOTOR          0x1210  /* USB Product ID of Motor (reserved) */
  62 #define USB_DEVICE_ID_LD_COM3LAB        0x2000  /* USB Product ID of COM3LAB */
  63 #define USB_DEVICE_ID_LD_TELEPORT       0x2010  /* USB Product ID of Terminal Adapter */
  64 #define USB_DEVICE_ID_LD_NETWORKANALYSER 0x2020 /* USB Product ID of Network Analyser */
  65 #define USB_DEVICE_ID_LD_POWERCONTROL   0x2030  /* USB Product ID of Converter Control Unit */
  66 #define USB_DEVICE_ID_LD_MACHINETEST    0x2040  /* USB Product ID of Machine Test System */
  67 #define USB_DEVICE_ID_LD_MOSTANALYSER   0x2050  /* USB Product ID of MOST Protocol Analyser */
  68 #define USB_DEVICE_ID_LD_MOSTANALYSER2  0x2051  /* USB Product ID of MOST Protocol Analyser 2 */
  69 #define USB_DEVICE_ID_LD_ABSESP         0x2060  /* USB Product ID of ABS ESP */
  70 #define USB_DEVICE_ID_LD_AUTODATABUS    0x2070  /* USB Product ID of Automotive Data Buses */
  71 #define USB_DEVICE_ID_LD_MCT            0x2080  /* USB Product ID of Microcontroller technique */
  72 #define USB_DEVICE_ID_LD_HYBRID         0x2090  /* USB Product ID of Automotive Hybrid */
  73 #define USB_DEVICE_ID_LD_HEATCONTROL    0x20A0  /* USB Product ID of Heat control */
  74
  75 #ifdef CONFIG_USB_DYNAMIC_MINORS
  76 #define USB_LD_MINOR_BASE       0
  77 #else
  78 #define USB_LD_MINOR_BASE       176
  79 #endif
  80
  81 /* table of devices that work with this driver */
  82 static const struct usb_device_id ld_usb_table[] = {
  83         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CASSY) },
  84         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CASSY2) },
  85         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POCKETCASSY) },
  86         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POCKETCASSY2) },
  87         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOBILECASSY) },
  88         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOBILECASSY2) },
  89         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYVOLTAGE) },
  90         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYCURRENT) },
  91         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYTIME) },
  92         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYTEMPERATURE) },
  93         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYPH) },
  94         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POWERANALYSERCASSY) },
  95         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CONVERTERCONTROLLERCASSY) },
  96         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MACHINETESTCASSY) },
  97         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_JWM) },
  98         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_DMMP) },
  99         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIP) },
 100         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIC) },
 101         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIB) },
 102         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_XRAY) },
 103         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_XRAY2) },
 104         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_VIDEOCOM) },
 105         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOTOR) },
 106         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_COM3LAB) },
 107         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_TELEPORT) },
 108         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_NETWORKANALYSER) },
 109         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POWERCONTROL) },
 110         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MACHINETEST) },
 111         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOSTANALYSER) },
 112         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOSTANALYSER2) },
 113         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_ABSESP) },
 114         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_AUTODATABUS) },
 115         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MCT) },
 116         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_HYBRID) },
 117         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_HEATCONTROL) },
 118         { }                                     /* Terminating entry */
 119 };
 120 MODULE_DEVICE_TABLE(usb, ld_usb_table);
 121 MODULE_AUTHOR("Michael Hund <mhund@ld-didactic.de>");
 122 MODULE_DESCRIPTION("LD USB Driver");
 123 MODULE_LICENSE("GPL");
 124 MODULE_SUPPORTED_DEVICE("LD USB Devices");
 125
 126 /* All interrupt in transfers are collected in a ring buffer to
 127  * avoid racing conditions and get better performance of the driver.
 128  */
 129 static int ring_buffer_size = 128;
 130 module_param(ring_buffer_size, int, 0000);
 131 MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size in reports");
 132
 133 /* The write_buffer can contain more than one interrupt out transfer.
 134  */
 135 static int write_buffer_size = 10;
 136 module_param(write_buffer_size, int, 0000);
 137 MODULE_PARM_DESC(write_buffer_size, "Write buffer size in reports");
 138
 139 /* As of kernel version 2.6.4 ehci-hcd uses an
 140  * "only one interrupt transfer per frame" shortcut
 141  * to simplify the scheduling of periodic transfers.
 142  * This conflicts with our standard 1ms intervals for in and out URBs.
 143  * We use default intervals of 2ms for in and 2ms for out transfers,
 144  * which should be fast enough.
 145  * Increase the interval to allow more devices that do interrupt transfers,
 146  * or set to 1 to use the standard interval from the endpoint descriptors.
 147  */
 148 static int min_interrupt_in_interval = 2;
 149 module_param(min_interrupt_in_interval, int, 0000);
 150 MODULE_PARM_DESC(min_interrupt_in_interval, "Minimum interrupt in interval in ms");
 151
 152 static int min_interrupt_out_interval = 2;
 153 module_param(min_interrupt_out_interval, int, 0000);
 154 MODULE_PARM_DESC(min_interrupt_out_interval, "Minimum interrupt out interval in ms");
 155
 156 /* Structure to hold all of our device specific stuff */
 157 struct ld_usb {
 158         struct mutex            mutex;          /* locks this structure */
 159         struct usb_interface    *intf;          /* save off the usb interface pointer */
 160         unsigned long           disconnected:1;
 161
 162         int                     open_count;     /* number of times this port has been opened */
 163
 164         char                    *ring_buffer;
 165         unsigned int            ring_head;
 166         unsigned int            ring_tail;
 167
 168         wait_queue_head_t       read_wait;
 169         wait_queue_head_t       write_wait;
 170
 171         char                    *interrupt_in_buffer;
 172         struct usb_endpoint_descriptor *interrupt_in_endpoint;
 173         struct urb              *interrupt_in_urb;
 174         int                     interrupt_in_interval;
 175         size_t                  interrupt_in_endpoint_size;
 176         int                     interrupt_in_running;
 177         int                     interrupt_in_done;
 178         int                     buffer_overflow;
 179         spinlock_t              rbsl;
 180
 181         char                    *interrupt_out_buffer;
 182         struct usb_endpoint_descriptor *interrupt_out_endpoint;
 183         struct urb              *interrupt_out_urb;
 184         int                     interrupt_out_interval;
 185         size_t                  interrupt_out_endpoint_size;
 186         int                     interrupt_out_busy;
 187 };
 188
 189 static struct usb_driver ld_usb_driver;
 190
 191 /**
 192  *      ld_usb_abort_transfers
 193  *      aborts transfers and frees associated data structures
 194  */
 195 static void ld_usb_abort_transfers(struct ld_usb *dev)
 196 {
 197         /* shutdown transfer */
 198         if (dev->interrupt_in_running) {
 199                 dev->interrupt_in_running = 0;
 200                 usb_kill_urb(dev->interrupt_in_urb);
 201         }
 202         if (dev->interrupt_out_busy)
 203                 usb_kill_urb(dev->interrupt_out_urb);
 204 }
 205
 206 /**
 207  *      ld_usb_delete
 208  */
 209 static void ld_usb_delete(struct ld_usb *dev)
 210 {
 211         /* free data structures */
 212         usb_free_urb(dev->interrupt_in_urb);
 213         usb_free_urb(dev->interrupt_out_urb);
 214         kfree(dev->ring_buffer);
 215         kfree(dev->interrupt_in_buffer);
 216         kfree(dev->interrupt_out_buffer);
 217         kfree(dev);
 218 }
 219
 220 /**
 221  *      ld_usb_interrupt_in_callback
 222  */
 223 static void ld_usb_interrupt_in_callback(struct urb *urb)
 224 {
 225         struct ld_usb *dev = urb->context;
 226         size_t *actual_buffer;
 227         unsigned int next_ring_head;
 228         int status = urb->status;
 229         int retval;
 230
 231         if (status) {
 232                 if (status == -ENOENT ||
 233                     status == -ECONNRESET ||
 234                     status == -ESHUTDOWN) {
 235                         goto exit;
 236                 } else {
 237                         dev_dbg(&dev->intf->dev,
 238                                 "%s: nonzero status received: %d\n", __func__,
 239                                 status);
 240                         spin_lock(&dev->rbsl);
 241                         goto resubmit; /* maybe we can recover */
 242                 }
 243         }
 244
 245         spin_lock(&dev->rbsl);
 246         if (urb->actual_length > 0) {
 247                 next_ring_head = (dev->ring_head+1) % ring_buffer_size;
 248                 if (next_ring_head != dev->ring_tail) {
 249                         actual_buffer = (size_t *)(dev->ring_buffer + dev->ring_head * (sizeof(size_t)+dev->interrupt_in_endpoint_size));
 250                         /* actual_buffer gets urb->actual_length + interrupt_in_buffer */
 251                         *actual_buffer = urb->actual_length;
 252                         memcpy(actual_buffer+1, dev->interrupt_in_buffer, urb->actual_length);
 253                         dev->ring_head = next_ring_head;
 254                         dev_dbg(&dev->intf->dev, "%s: received %d bytes\n",
 255                                 __func__, urb->actual_length);
 256                 } else {
 257                         dev_warn(&dev->intf->dev,
 258                                  "Ring buffer overflow, %d bytes dropped\n",
 259                                  urb->actual_length);
 260                         dev->buffer_overflow = 1;
 261                 }
 262         }
 263
 264 resubmit:
 265         /* resubmit if we're still running */
 266         if (dev->interrupt_in_running && !dev->buffer_overflow) {
 267                 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
 268                 if (retval) {
 269                         dev_err(&dev->intf->dev,
 270                                 "usb_submit_urb failed (%d)\n", retval);
 271                         dev->buffer_overflow = 1;
 272                 }
 273         }
 274         spin_unlock(&dev->rbsl);
 275 exit:
 276         dev->interrupt_in_done = 1;
 277         wake_up_interruptible(&dev->read_wait);
 278 }
 279
 280 /**
 281  *      ld_usb_interrupt_out_callback
 282  */
 283 static void ld_usb_interrupt_out_callback(struct urb *urb)
 284 {
 285         struct ld_usb *dev = urb->context;
 286         int status = urb->status;
 287
 288         /* sync/async unlink faults aren't errors */
 289         if (status && !(status == -ENOENT ||
 290                         status == -ECONNRESET ||
 291                         status == -ESHUTDOWN))
 292                 dev_dbg(&dev->intf->dev,
 293                         "%s - nonzero write interrupt status received: %d\n",
 294                         __func__, status);
 295
 296         dev->interrupt_out_busy = 0;
 297         wake_up_interruptible(&dev->write_wait);
 298 }
 299
 300 /**
 301  *      ld_usb_open
 302  */
 303 static int ld_usb_open(struct inode *inode, struct file *file)
 304 {
 305         struct ld_usb *dev;
 306         int subminor;
 307         int retval;
 308         struct usb_interface *interface;
 309
 310         nonseekable_open(inode, file);
 311         subminor = iminor(inode);
 312
 313         interface = usb_find_interface(&ld_usb_driver, subminor);
 314
 315         if (!interface) {
 316                 printk(KERN_ERR "%s - error, can't find device for minor %d\n",
 317                        __func__, subminor);
 318                 return -ENODEV;
 319         }
 320
 321         dev = usb_get_intfdata(interface);
 322
 323         if (!dev)
 324                 return -ENODEV;
 325
 326         /* lock this device */
 327         if (mutex_lock_interruptible(&dev->mutex))
 328                 return -ERESTARTSYS;
 329
 330         /* allow opening only once */
 331         if (dev->open_count) {
 332                 retval = -EBUSY;
 333                 goto unlock_exit;
 334         }
 335         dev->open_count = 1;
 336
 337         /* initialize in direction */
 338         dev->ring_head = 0;
 339         dev->ring_tail = 0;
 340         dev->buffer_overflow = 0;
 341         usb_fill_int_urb(dev->interrupt_in_urb,
 342                          interface_to_usbdev(interface),
 343                          usb_rcvintpipe(interface_to_usbdev(interface),
 344                                         dev->interrupt_in_endpoint->bEndpointAddress),
 345                          dev->interrupt_in_buffer,
 346                          dev->interrupt_in_endpoint_size,
 347                          ld_usb_interrupt_in_callback,
 348                          dev,
 349                          dev->interrupt_in_interval);
 350
 351         dev->interrupt_in_running = 1;
 352         dev->interrupt_in_done = 0;
 353
 354         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 355         if (retval) {
 356                 dev_err(&interface->dev, "Couldn't submit interrupt_in_urb %d\n", retval);
 357                 dev->interrupt_in_running = 0;
 358                 dev->open_count = 0;
 359                 goto unlock_exit;
 360         }
 361
 362         /* save device in the file's private structure */
 363         file->private_data = dev;
 364
 365 unlock_exit:
 366         mutex_unlock(&dev->mutex);
 367
 368         return retval;
 369 }
 370
 371 /**
 372  *      ld_usb_release
 373  */
 374 static int ld_usb_release(struct inode *inode, struct file *file)
 375 {
 376         struct ld_usb *dev;
 377         int retval = 0;
 378
 379         dev = file->private_data;
 380
 381         if (dev == NULL) {
 382                 retval = -ENODEV;
 383                 goto exit;
 384         }
 385
 386         mutex_lock(&dev->mutex);
 387
 388         if (dev->open_count != 1) {
 389                 retval = -ENODEV;
 390                 goto unlock_exit;
 391         }
 392         if (dev->disconnected) {
 393                 /* the device was unplugged before the file was released */
 394                 mutex_unlock(&dev->mutex);
 395                 /* unlock here as ld_usb_delete frees dev */
 396                 ld_usb_delete(dev);
 397                 goto exit;
 398         }
 399
 400         /* wait until write transfer is finished */
 401         if (dev->interrupt_out_busy)
 402                 wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 403         ld_usb_abort_transfers(dev);
 404         dev->open_count = 0;
 405
 406 unlock_exit:
 407         mutex_unlock(&dev->mutex);
 408
 409 exit:
 410         return retval;
 411 }
 412
 413 /**
 414  *      ld_usb_poll
 415  */
 416 static unsigned int ld_usb_poll(struct file *file, poll_table *wait)
 417 {
 418         struct ld_usb *dev;
 419         unsigned int mask = 0;
 420
 421         dev = file->private_data;
 422
 423         if (dev->disconnected)
 424                 return POLLERR | POLLHUP;
 425
 426         poll_wait(file, &dev->read_wait, wait);
 427         poll_wait(file, &dev->write_wait, wait);
 428
 429         if (dev->ring_head != dev->ring_tail)
 430                 mask |= POLLIN | POLLRDNORM;
 431         if (!dev->interrupt_out_busy)
 432                 mask |= POLLOUT | POLLWRNORM;
 433
 434         return mask;
 435 }
 436
 437 /**
 438  *      ld_usb_read
 439  */
 440 static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
 441                            loff_t *ppos)
 442 {
 443         struct ld_usb *dev;
 444         size_t *actual_buffer;
 445         size_t bytes_to_read;
 446         int retval = 0;
 447         int rv;
 448
 449         dev = file->private_data;
 450
 451         /* verify that we actually have some data to read */
 452         if (count == 0)
 453                 goto exit;
 454
 455         /* lock this object */
 456         if (mutex_lock_interruptible(&dev->mutex)) {
 457                 retval = -ERESTARTSYS;
 458                 goto exit;
 459         }
 460
 461         /* verify that the device wasn't unplugged */
 462         if (dev->disconnected) {
 463                 retval = -ENODEV;
 464                 printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
 465                 goto unlock_exit;
 466         }
 467
 468         /* wait for data */
 469         spin_lock_irq(&dev->rbsl);
 470         while (dev->ring_head == dev->ring_tail) {
 471                 dev->interrupt_in_done = 0;
 472                 spin_unlock_irq(&dev->rbsl);
 473                 if (file->f_flags & O_NONBLOCK) {
 474                         retval = -EAGAIN;
 475                         goto unlock_exit;
 476                 }
 477                 retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
 478                 if (retval < 0)
 479                         goto unlock_exit;
 480
 481                 spin_lock_irq(&dev->rbsl);
 482         }
 483         spin_unlock_irq(&dev->rbsl);
 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         if (*actual_buffer > dev->interrupt_in_endpoint_size) {
 488                 retval = -EIO;
 489                 goto unlock_exit;
 490         }
 491         bytes_to_read = min(count, *actual_buffer);
 492         if (bytes_to_read < *actual_buffer)
 493                 dev_warn(&dev->intf->dev, "Read buffer overflow, %zu bytes dropped\n",
 494                          *actual_buffer-bytes_to_read);
 495
 496         /* copy one interrupt_in_buffer from ring_buffer into userspace */
 497         if (copy_to_user(buffer, actual_buffer+1, bytes_to_read)) {
 498                 retval = -EFAULT;
 499                 goto unlock_exit;
 500         }
 501         retval = bytes_to_read;
 502
 503         spin_lock_irq(&dev->rbsl);
 504         dev->ring_tail = (dev->ring_tail + 1) % ring_buffer_size;
 505
 506         if (dev->buffer_overflow) {
 507                 dev->buffer_overflow = 0;
 508                 spin_unlock_irq(&dev->rbsl);
 509                 rv = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 510                 if (rv < 0)
 511                         dev->buffer_overflow = 1;
 512         } else {
 513                 spin_unlock_irq(&dev->rbsl);
 514         }
 515
 516 unlock_exit:
 517         /* unlock the device */
 518         mutex_unlock(&dev->mutex);
 519
 520 exit:
 521         return retval;
 522 }
 523
 524 /**
 525  *      ld_usb_write
 526  */
 527 static ssize_t ld_usb_write(struct file *file, const char __user *buffer,
 528                             size_t count, loff_t *ppos)
 529 {
 530         struct ld_usb *dev;
 531         size_t bytes_to_write;
 532         int retval = 0;
 533
 534         dev = file->private_data;
 535
 536         /* verify that we actually have some data to write */
 537         if (count == 0)
 538                 goto exit;
 539
 540         /* lock this object */
 541         if (mutex_lock_interruptible(&dev->mutex)) {
 542                 retval = -ERESTARTSYS;
 543                 goto exit;
 544         }
 545
 546         /* verify that the device wasn't unplugged */
 547         if (dev->disconnected) {
 548                 retval = -ENODEV;
 549                 printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
 550                 goto unlock_exit;
 551         }
 552
 553         /* wait until previous transfer is finished */
 554         if (dev->interrupt_out_busy) {
 555                 if (file->f_flags & O_NONBLOCK) {
 556                         retval = -EAGAIN;
 557                         goto unlock_exit;
 558                 }
 559                 retval = wait_event_interruptible(dev->write_wait, !dev->interrupt_out_busy);
 560                 if (retval < 0) {
 561                         goto unlock_exit;
 562                 }
 563         }
 564
 565         /* write the data into interrupt_out_buffer from userspace */
 566         bytes_to_write = min(count, write_buffer_size*dev->interrupt_out_endpoint_size);
 567         if (bytes_to_write < count)
 568                 dev_warn(&dev->intf->dev, "Write buffer overflow, %zu bytes dropped\n",
 569                         count - bytes_to_write);
 570         dev_dbg(&dev->intf->dev, "%s: count = %zu, bytes_to_write = %zu\n",
 571                 __func__, count, bytes_to_write);
 572
 573         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 574                 retval = -EFAULT;
 575                 goto unlock_exit;
 576         }
 577
 578         if (dev->interrupt_out_endpoint == NULL) {
 579                 /* try HID_REQ_SET_REPORT=9 on control_endpoint instead of interrupt_out_endpoint */
 580                 retval = usb_control_msg(interface_to_usbdev(dev->intf),
 581                                          usb_sndctrlpipe(interface_to_usbdev(dev->intf), 0),
 582                                          9,
 583                                          USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
 584                                          1 << 8, 0,
 585                                          dev->interrupt_out_buffer,
 586                                          bytes_to_write,
 587                                          USB_CTRL_SET_TIMEOUT);
 588                 if (retval < 0)
 589                         dev_err(&dev->intf->dev,
 590                                 "Couldn't submit HID_REQ_SET_REPORT %d\n",
 591                                 retval);
 592                 goto unlock_exit;
 593         }
 594
 595         /* send off the urb */
 596         usb_fill_int_urb(dev->interrupt_out_urb,
 597                          interface_to_usbdev(dev->intf),
 598                          usb_sndintpipe(interface_to_usbdev(dev->intf),
 599                                         dev->interrupt_out_endpoint->bEndpointAddress),
 600                          dev->interrupt_out_buffer,
 601                          bytes_to_write,
 602                          ld_usb_interrupt_out_callback,
 603                          dev,
 604                          dev->interrupt_out_interval);
 605
 606         dev->interrupt_out_busy = 1;
 607         wmb();
 608
 609         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 610         if (retval) {
 611                 dev->interrupt_out_busy = 0;
 612                 dev_err(&dev->intf->dev,
 613                         "Couldn't submit interrupt_out_urb %d\n", retval);
 614                 goto unlock_exit;
 615         }
 616         retval = bytes_to_write;
 617
 618 unlock_exit:
 619         /* unlock the device */
 620         mutex_unlock(&dev->mutex);
 621
 622 exit:
 623         return retval;
 624 }
 625
 626 /* file operations needed when we register this driver */
 627 static const struct file_operations ld_usb_fops = {
 628         .owner =        THIS_MODULE,
 629         .read  =        ld_usb_read,
 630         .write =        ld_usb_write,
 631         .open =         ld_usb_open,
 632         .release =      ld_usb_release,
 633         .poll =         ld_usb_poll,
 634         .llseek =       no_llseek,
 635 };
 636
 637 /*
 638  * usb class driver info in order to get a minor number from the usb core,
 639  * and to have the device registered with the driver core
 640  */
 641 static struct usb_class_driver ld_usb_class = {
 642         .name =         "ldusb%d",
 643         .fops =         &ld_usb_fops,
 644         .minor_base =   USB_LD_MINOR_BASE,
 645 };
 646
 647 /**
 648  *      ld_usb_probe
 649  *
 650  *      Called by the usb core when a new device is connected that it thinks
 651  *      this driver might be interested in.
 652  */
 653 static int ld_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
 654 {
 655         struct usb_device *udev = interface_to_usbdev(intf);
 656         struct ld_usb *dev = NULL;
 657         struct usb_host_interface *iface_desc;
 658         char *buffer;
 659         int retval = -ENOMEM;
 660         int res;
 661
 662         /* allocate memory for our device state and initialize it */
 663
 664         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 665         if (!dev)
 666                 goto exit;
 667         mutex_init(&dev->mutex);
 668         spin_lock_init(&dev->rbsl);
 669         dev->intf = intf;
 670         init_waitqueue_head(&dev->read_wait);
 671         init_waitqueue_head(&dev->write_wait);
 672
 673         /* workaround for early firmware versions on fast computers */
 674         if ((le16_to_cpu(udev->descriptor.idVendor) == USB_VENDOR_ID_LD) &&
 675             ((le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_CASSY) ||
 676              (le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_COM3LAB)) &&
 677             (le16_to_cpu(udev->descriptor.bcdDevice) <= 0x103)) {
 678                 buffer = kmalloc(256, GFP_KERNEL);
 679                 if (!buffer)
 680                         goto error;
 681                 /* usb_string makes SETUP+STALL to leave always ControlReadLoop */
 682                 usb_string(udev, 255, buffer, 256);
 683                 kfree(buffer);
 684         }
 685
 686         iface_desc = intf->cur_altsetting;
 687
 688         res = usb_find_last_int_in_endpoint(iface_desc,
 689                         &dev->interrupt_in_endpoint);
 690         if (res) {
 691                 dev_err(&intf->dev, "Interrupt in endpoint not found\n");
 692                 retval = res;
 693                 goto error;
 694         }
 695
 696         res = usb_find_last_int_out_endpoint(iface_desc,
 697                         &dev->interrupt_out_endpoint);
 698         if (res)
 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 = kcalloc(ring_buffer_size,
 703                         sizeof(size_t) + dev->interrupt_in_endpoint_size,
 704                         GFP_KERNEL);
 705         if (!dev->ring_buffer)
 706                 goto error;
 707         dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 708         if (!dev->interrupt_in_buffer)
 709                 goto error;
 710         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 711         if (!dev->interrupt_in_urb)
 712                 goto error;
 713         dev->interrupt_out_endpoint_size = dev->interrupt_out_endpoint ? usb_endpoint_maxp(dev->interrupt_out_endpoint) :
 714                                                                          udev->descriptor.bMaxPacketSize0;
 715         dev->interrupt_out_buffer = kmalloc(write_buffer_size*dev->interrupt_out_endpoint_size, GFP_KERNEL);
 716         if (!dev->interrupt_out_buffer)
 717                 goto error;
 718         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 719         if (!dev->interrupt_out_urb)
 720                 goto error;
 721         dev->interrupt_in_interval = min_interrupt_in_interval > dev->interrupt_in_endpoint->bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 722         if (dev->interrupt_out_endpoint)
 723                 dev->interrupt_out_interval = min_interrupt_out_interval > dev->interrupt_out_endpoint->bInterval ? min_interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 724
 725         /* we can register the device now, as it is ready */
 726         usb_set_intfdata(intf, dev);
 727
 728         retval = usb_register_dev(intf, &ld_usb_class);
 729         if (retval) {
 730                 /* something prevented us from registering this driver */
 731                 dev_err(&intf->dev, "Not able to get a minor for this device.\n");
 732                 usb_set_intfdata(intf, NULL);
 733                 goto error;
 734         }
 735
 736         /* let the user know what node this device is now attached to */
 737         dev_info(&intf->dev, "LD USB Device #%d now attached to major %d minor %d\n",
 738                 (intf->minor - USB_LD_MINOR_BASE), USB_MAJOR, intf->minor);
 739
 740 exit:
 741         return retval;
 742
 743 error:
 744         ld_usb_delete(dev);
 745
 746         return retval;
 747 }
 748
 749 /**
 750  *      ld_usb_disconnect
 751  *
 752  *      Called by the usb core when the device is removed from the system.
 753  */
 754 static void ld_usb_disconnect(struct usb_interface *intf)
 755 {
 756         struct ld_usb *dev;
 757         int minor;
 758
 759         dev = usb_get_intfdata(intf);
 760         usb_set_intfdata(intf, NULL);
 761
 762         minor = intf->minor;
 763
 764         /* give back our minor */
 765         usb_deregister_dev(intf, &ld_usb_class);
 766
 767         usb_poison_urb(dev->interrupt_in_urb);
 768         usb_poison_urb(dev->interrupt_out_urb);
 769
 770         mutex_lock(&dev->mutex);
 771
 772         /* if the device is not opened, then we clean up right now */
 773         if (!dev->open_count) {
 774                 mutex_unlock(&dev->mutex);
 775                 ld_usb_delete(dev);
 776         } else {
 777                 dev->disconnected = 1;
 778                 /* wake up pollers */
 779                 wake_up_interruptible_all(&dev->read_wait);
 780                 wake_up_interruptible_all(&dev->write_wait);
 781                 mutex_unlock(&dev->mutex);
 782         }
 783
 784         dev_info(&intf->dev, "LD USB Device #%d now disconnected\n",
 785                  (minor - USB_LD_MINOR_BASE));
 786 }
 787
 788 /* usb specific object needed to register this driver with the usb subsystem */
 789 static struct usb_driver ld_usb_driver = {
 790         .name =         "ldusb",
 791         .probe =        ld_usb_probe,
 792         .disconnect =   ld_usb_disconnect,
 793         .id_table =     ld_usb_table,
 794 };
 795
 796 module_usb_driver(ld_usb_driver);
 797