LXR linux/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#define USB_VENDOR_ID_VERNIER           0x08f7
  73#define USB_DEVICE_ID_VERNIER_GOTEMP    0x0002
  74#define USB_DEVICE_ID_VERNIER_SKIP      0x0003
  75#define USB_DEVICE_ID_VERNIER_CYCLOPS   0x0004
  76#define USB_DEVICE_ID_VERNIER_LCSPEC    0x0006
  77
  78#ifdef CONFIG_USB_DYNAMIC_MINORS
  79#define USB_LD_MINOR_BASE       0
  80#else
  81#define USB_LD_MINOR_BASE       176
  82#endif
  83
  84/* table of devices that work with this driver */
  85static const struct usb_device_id ld_usb_table[] = {
  86        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CASSY) },
  87        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CASSY2) },
  88        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POCKETCASSY) },
  89        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POCKETCASSY2) },
  90        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOBILECASSY) },
  91        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOBILECASSY2) },
  92        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYVOLTAGE) },
  93        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYCURRENT) },
  94        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYTIME) },
  95        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYTEMPERATURE) },
  96        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYPH) },
  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        { USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_GOTEMP) },
 119        { USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_SKIP) },
 120        { USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_CYCLOPS) },
 121        { USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_LCSPEC) },
 122        { }                                     /* Terminating entry */
 123};
 124MODULE_DEVICE_TABLE(usb, ld_usb_table);
 125MODULE_VERSION("V0.14");
 126MODULE_AUTHOR("Michael Hund <mhund@ld-didactic.de>");
 127MODULE_DESCRIPTION("LD USB Driver");
 128MODULE_LICENSE("GPL");
 129MODULE_SUPPORTED_DEVICE("LD USB Devices");
 130
 131/* All interrupt in transfers are collected in a ring buffer to
 132 * avoid racing conditions and get better performance of the driver.
 133 */
 134static int ring_buffer_size = 128;
 135module_param(ring_buffer_size, int, 0);
 136MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size in reports");
 137
 138/* The write_buffer can contain more than one interrupt out transfer.
 139 */
 140static int write_buffer_size = 10;
 141module_param(write_buffer_size, int, 0);
 142MODULE_PARM_DESC(write_buffer_size, "Write buffer size in reports");
 143
 144/* As of kernel version 2.6.4 ehci-hcd uses an
 145 * "only one interrupt transfer per frame" shortcut
 146 * to simplify the scheduling of periodic transfers.
 147 * This conflicts with our standard 1ms intervals for in and out URBs.
 148 * We use default intervals of 2ms for in and 2ms for out transfers,
 149 * which should be fast enough.
 150 * Increase the interval to allow more devices that do interrupt transfers,
 151 * or set to 1 to use the standard interval from the endpoint descriptors.
 152 */
 153static int min_interrupt_in_interval = 2;
 154module_param(min_interrupt_in_interval, int, 0);
 155MODULE_PARM_DESC(min_interrupt_in_interval, "Minimum interrupt in interval in ms");
 156
 157static int min_interrupt_out_interval = 2;
 158module_param(min_interrupt_out_interval, int, 0);
 159MODULE_PARM_DESC(min_interrupt_out_interval, "Minimum interrupt out interval in ms");
 160
 161/* Structure to hold all of our device specific stuff */
 162struct ld_usb {
 163        struct mutex            mutex;          /* locks this structure */
 164        struct usb_interface*   intf;           /* save off the usb interface pointer */
 165
 166        int                     open_count;     /* number of times this port has been opened */
 167
 168        char*                   ring_buffer;
 169        unsigned int            ring_head;
 170        unsigned int            ring_tail;
 171
 172        wait_queue_head_t       read_wait;
 173        wait_queue_head_t       write_wait;
 174
 175        char*                   interrupt_in_buffer;
 176        struct usb_endpoint_descriptor* interrupt_in_endpoint;
 177        struct urb*             interrupt_in_urb;
 178        int                     interrupt_in_interval;
 179        size_t                  interrupt_in_endpoint_size;
 180        int                     interrupt_in_running;
 181        int                     interrupt_in_done;
 182        int                     buffer_overflow;
 183        spinlock_t              rbsl;
 184
 185        char*                   interrupt_out_buffer;
 186        struct usb_endpoint_descriptor* interrupt_out_endpoint;
 187        struct urb*             interrupt_out_urb;
 188        int                     interrupt_out_interval;
 189        size_t                  interrupt_out_endpoint_size;
 190        int                     interrupt_out_busy;
 191};
 192
 193static struct usb_driver ld_usb_driver;
 194
 195/**
 196 *      ld_usb_abort_transfers
 197 *      aborts transfers and frees associated data structures
 198 */
 199static void ld_usb_abort_transfers(struct ld_usb *dev)
 200{
 201        /* shutdown transfer */
 202        if (dev->interrupt_in_running) {
 203                dev->interrupt_in_running = 0;
 204                if (dev->intf)
 205                        usb_kill_urb(dev->interrupt_in_urb);
 206        }
 207        if (dev->interrupt_out_busy)
 208                if (dev->intf)
 209                        usb_kill_urb(dev->interrupt_out_urb);
 210}
 211
 212/**
 213 *      ld_usb_delete
 214 */
 215static void ld_usb_delete(struct ld_usb *dev)
 216{
 217        ld_usb_abort_transfers(dev);
 218
 219        /* free data structures */
 220        usb_free_urb(dev->interrupt_in_urb);
 221        usb_free_urb(dev->interrupt_out_urb);
 222        kfree(dev->ring_buffer);
 223        kfree(dev->interrupt_in_buffer);
 224        kfree(dev->interrupt_out_buffer);
 225        kfree(dev);
 226}
 227
 228/**
 229 *      ld_usb_interrupt_in_callback
 230 */
 231static void ld_usb_interrupt_in_callback(struct urb *urb)
 232{
 233        struct ld_usb *dev = urb->context;
 234        size_t *actual_buffer;
 235        unsigned int next_ring_head;
 236        int status = urb->status;
 237        int retval;
 238
 239        if (status) {
 240                if (status == -ENOENT ||
 241                    status == -ECONNRESET ||
 242                    status == -ESHUTDOWN) {
 243                        goto exit;
 244                } else {
 245                        dev_dbg(&dev->intf->dev,
 246                                "%s: nonzero status received: %d\n", __func__,
 247                                status);
 248                        spin_lock(&dev->rbsl);
 249                        goto resubmit; /* maybe we can recover */
 250                }
 251        }
 252
 253        spin_lock(&dev->rbsl);
 254        if (urb->actual_length > 0) {
 255                next_ring_head = (dev->ring_head+1) % ring_buffer_size;
 256                if (next_ring_head != dev->ring_tail) {
 257                        actual_buffer = (size_t*)(dev->ring_buffer + dev->ring_head*(sizeof(size_t)+dev->interrupt_in_endpoint_size));
 258                        /* actual_buffer gets urb->actual_length + interrupt_in_buffer */
 259                        *actual_buffer = urb->actual_length;
 260                        memcpy(actual_buffer+1, dev->interrupt_in_buffer, urb->actual_length);
 261                        dev->ring_head = next_ring_head;
 262                        dev_dbg(&dev->intf->dev, "%s: received %d bytes\n",
 263                                __func__, urb->actual_length);
 264                } else {
 265                        dev_warn(&dev->intf->dev,
 266                                 "Ring buffer overflow, %d bytes dropped\n",
 267                                 urb->actual_length);
 268                        dev->buffer_overflow = 1;
 269                }
 270        }
 271
 272resubmit:
 273        /* resubmit if we're still running */
 274        if (dev->interrupt_in_running && !dev->buffer_overflow && dev->intf) {
 275                retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
 276                if (retval) {
 277                        dev_err(&dev->intf->dev,
 278                                "usb_submit_urb failed (%d)\n", retval);
 279                        dev->buffer_overflow = 1;
 280                }
 281        }
 282        spin_unlock(&dev->rbsl);
 283exit:
 284        dev->interrupt_in_done = 1;
 285        wake_up_interruptible(&dev->read_wait);
 286}
 287
 288/**
 289 *      ld_usb_interrupt_out_callback
 290 */
 291static void ld_usb_interrupt_out_callback(struct urb *urb)
 292{
 293        struct ld_usb *dev = urb->context;
 294        int status = urb->status;
 295
 296        /* sync/async unlink faults aren't errors */
 297        if (status && !(status == -ENOENT ||
 298                        status == -ECONNRESET ||
 299                        status == -ESHUTDOWN))
 300                dev_dbg(&dev->intf->dev,
 301                        "%s - nonzero write interrupt status received: %d\n",
 302                        __func__, status);
 303
 304        dev->interrupt_out_busy = 0;
 305        wake_up_interruptible(&dev->write_wait);
 306}
 307
 308/**
 309 *      ld_usb_open
 310 */
 311static int ld_usb_open(struct inode *inode, struct file *file)
 312{
 313        struct ld_usb *dev;
 314        int subminor;
 315        int retval;
 316        struct usb_interface *interface;
 317
 318        nonseekable_open(inode, file);
 319        subminor = iminor(inode);
 320
 321        interface = usb_find_interface(&ld_usb_driver, subminor);
 322
 323        if (!interface) {
 324                printk(KERN_ERR "%s - error, can't find device for minor %d\n",
 325                       __func__, subminor);
 326                return -ENODEV;
 327        }
 328
 329        dev = usb_get_intfdata(interface);
 330
 331        if (!dev)
 332                return -ENODEV;
 333
 334        /* lock this device */
 335        if (mutex_lock_interruptible(&dev->mutex))
 336                return -ERESTARTSYS;
 337
 338        /* allow opening only once */
 339        if (dev->open_count) {
 340                retval = -EBUSY;
 341                goto unlock_exit;
 342        }
 343        dev->open_count = 1;
 344
 345        /* initialize in direction */
 346        dev->ring_head = 0;
 347        dev->ring_tail = 0;
 348        dev->buffer_overflow = 0;
 349        usb_fill_int_urb(dev->interrupt_in_urb,
 350                         interface_to_usbdev(interface),
 351                         usb_rcvintpipe(interface_to_usbdev(interface),
 352                                        dev->interrupt_in_endpoint->bEndpointAddress),
 353                         dev->interrupt_in_buffer,
 354                         dev->interrupt_in_endpoint_size,
 355                         ld_usb_interrupt_in_callback,
 356                         dev,
 357                         dev->interrupt_in_interval);
 358
 359        dev->interrupt_in_running = 1;
 360        dev->interrupt_in_done = 0;
 361
 362        retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 363        if (retval) {
 364                dev_err(&interface->dev, "Couldn't submit interrupt_in_urb %d\n", retval);
 365                dev->interrupt_in_running = 0;
 366                dev->open_count = 0;
 367                goto unlock_exit;
 368        }
 369
 370        /* save device in the file's private structure */
 371        file->private_data = dev;
 372
 373unlock_exit:
 374        mutex_unlock(&dev->mutex);
 375
 376        return retval;
 377}
 378
 379/**
 380 *      ld_usb_release
 381 */
 382static int ld_usb_release(struct inode *inode, struct file *file)
 383{
 384        struct ld_usb *dev;
 385        int retval = 0;
 386
 387        dev = file->private_data;
 388
 389        if (dev == NULL) {
 390                retval = -ENODEV;
 391                goto exit;
 392        }
 393
 394        if (mutex_lock_interruptible(&dev->mutex)) {
 395                retval = -ERESTARTSYS;
 396                goto exit;
 397        }
 398
 399        if (dev->open_count != 1) {
 400                retval = -ENODEV;
 401                goto unlock_exit;
 402        }
 403        if (dev->intf == NULL) {
 404                /* the device was unplugged before the file was released */
 405                mutex_unlock(&dev->mutex);
 406                /* unlock here as ld_usb_delete frees dev */
 407                ld_usb_delete(dev);
 408                goto exit;
 409        }
 410
 411        /* wait until write transfer is finished */
 412        if (dev->interrupt_out_busy)
 413                wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 414        ld_usb_abort_transfers(dev);
 415        dev->open_count = 0;
 416
 417unlock_exit:
 418        mutex_unlock(&dev->mutex);
 419
 420exit:
 421        return retval;
 422}
 423
 424/**
 425 *      ld_usb_poll
 426 */
 427static unsigned int ld_usb_poll(struct file *file, poll_table *wait)
 428{
 429        struct ld_usb *dev;
 430        unsigned int mask = 0;
 431
 432        dev = file->private_data;
 433
 434        if (!dev->intf)
 435                return POLLERR | POLLHUP;
 436
 437        poll_wait(file, &dev->read_wait, wait);
 438        poll_wait(file, &dev->write_wait, wait);
 439
 440        if (dev->ring_head != dev->ring_tail)
 441                mask |= POLLIN | POLLRDNORM;
 442        if (!dev->interrupt_out_busy)
 443                mask |= POLLOUT | POLLWRNORM;
 444
 445        return mask;
 446}
 447
 448/**
 449 *      ld_usb_read
 450 */
 451static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
 452                           loff_t *ppos)
 453{
 454        struct ld_usb *dev;
 455        size_t *actual_buffer;
 456        size_t bytes_to_read;
 457        int retval = 0;
 458        int rv;
 459
 460        dev = file->private_data;
 461
 462        /* verify that we actually have some data to read */
 463        if (count == 0)
 464                goto exit;
 465
 466        /* lock this object */
 467        if (mutex_lock_interruptible(&dev->mutex)) {
 468                retval = -ERESTARTSYS;
 469                goto exit;
 470        }
 471
 472        /* verify that the device wasn't unplugged */
 473        if (dev->intf == NULL) {
 474                retval = -ENODEV;
 475                printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
 476                goto unlock_exit;
 477        }
 478
 479        /* wait for data */
 480        spin_lock_irq(&dev->rbsl);
 481        if (dev->ring_head == dev->ring_tail) {
 482                dev->interrupt_in_done = 0;
 483                spin_unlock_irq(&dev->rbsl);
 484                if (file->f_flags & O_NONBLOCK) {
 485                        retval = -EAGAIN;
 486                        goto unlock_exit;
 487                }
 488                retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
 489                if (retval < 0)
 490                        goto unlock_exit;
 491        } else {
 492                spin_unlock_irq(&dev->rbsl);
 493        }
 494
 495        /* actual_buffer contains actual_length + interrupt_in_buffer */
 496        actual_buffer = (size_t*)(dev->ring_buffer + dev->ring_tail*(sizeof(size_t)+dev->interrupt_in_endpoint_size));
 497        bytes_to_read = min(count, *actual_buffer);
 498        if (bytes_to_read < *actual_buffer)
 499                dev_warn(&dev->intf->dev, "Read buffer overflow, %zd bytes dropped\n",
 500                         *actual_buffer-bytes_to_read);
 501
 502        /* copy one interrupt_in_buffer from ring_buffer into userspace */
 503        if (copy_to_user(buffer, actual_buffer+1, bytes_to_read)) {
 504                retval = -EFAULT;
 505                goto unlock_exit;
 506        }
 507        dev->ring_tail = (dev->ring_tail+1) % ring_buffer_size;
 508
 509        retval = bytes_to_read;
 510
 511        spin_lock_irq(&dev->rbsl);
 512        if (dev->buffer_overflow) {
 513                dev->buffer_overflow = 0;
 514                spin_unlock_irq(&dev->rbsl);
 515                rv = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 516                if (rv < 0)
 517                        dev->buffer_overflow = 1;
 518        } else {
 519                spin_unlock_irq(&dev->rbsl);
 520        }
 521
 522unlock_exit:
 523        /* unlock the device */
 524        mutex_unlock(&dev->mutex);
 525
 526exit:
 527        return retval;
 528}
 529
 530/**
 531 *      ld_usb_write
 532 */
 533static ssize_t ld_usb_write(struct file *file, const char __user *buffer,
 534                            size_t count, loff_t *ppos)
 535{
 536        struct ld_usb *dev;
 537        size_t bytes_to_write;
 538        int retval = 0;
 539
 540        dev = file->private_data;
 541
 542        /* verify that we actually have some data to write */
 543        if (count == 0)
 544                goto exit;
 545
 546        /* lock this object */
 547        if (mutex_lock_interruptible(&dev->mutex)) {
 548                retval = -ERESTARTSYS;
 549                goto exit;
 550        }
 551
 552        /* verify that the device wasn't unplugged */
 553        if (dev->intf == NULL) {
 554                retval = -ENODEV;
 555                printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
 556                goto unlock_exit;
 557        }
 558
 559        /* wait until previous transfer is finished */
 560        if (dev->interrupt_out_busy) {
 561                if (file->f_flags & O_NONBLOCK) {
 562                        retval = -EAGAIN;
 563                        goto unlock_exit;
 564                }
 565                retval = wait_event_interruptible(dev->write_wait, !dev->interrupt_out_busy);
 566                if (retval < 0) {
 567                        goto unlock_exit;
 568                }
 569        }
 570
 571        /* write the data into interrupt_out_buffer from userspace */
 572        bytes_to_write = min(count, write_buffer_size*dev->interrupt_out_endpoint_size);
 573        if (bytes_to_write < count)
 574                dev_warn(&dev->intf->dev, "Write buffer overflow, %zd bytes dropped\n",count-bytes_to_write);
 575        dev_dbg(&dev->intf->dev, "%s: count = %zd, bytes_to_write = %zd\n",
 576                __func__, count, bytes_to_write);
 577
 578        if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 579                retval = -EFAULT;
 580                goto unlock_exit;
 581        }
 582
 583        if (dev->interrupt_out_endpoint == NULL) {
 584                /* try HID_REQ_SET_REPORT=9 on control_endpoint instead of interrupt_out_endpoint */
 585                retval = usb_control_msg(interface_to_usbdev(dev->intf),
 586                                         usb_sndctrlpipe(interface_to_usbdev(dev->intf), 0),
 587                                         9,
 588                                         USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
 589                                         1 << 8, 0,
 590                                         dev->interrupt_out_buffer,
 591                                         bytes_to_write,
 592                                         USB_CTRL_SET_TIMEOUT * HZ);
 593                if (retval < 0)
 594                        dev_err(&dev->intf->dev,
 595                                "Couldn't submit HID_REQ_SET_REPORT %d\n",
 596                                retval);
 597                goto unlock_exit;
 598        }
 599
 600        /* send off the urb */
 601        usb_fill_int_urb(dev->interrupt_out_urb,
 602                         interface_to_usbdev(dev->intf),
 603                         usb_sndintpipe(interface_to_usbdev(dev->intf),
 604                                        dev->interrupt_out_endpoint->bEndpointAddress),
 605                         dev->interrupt_out_buffer,
 606                         bytes_to_write,
 607                         ld_usb_interrupt_out_callback,
 608                         dev,
 609                         dev->interrupt_out_interval);
 610
 611        dev->interrupt_out_busy = 1;
 612        wmb();
 613
 614        retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 615        if (retval) {
 616                dev->interrupt_out_busy = 0;
 617                dev_err(&dev->intf->dev,
 618                        "Couldn't submit interrupt_out_urb %d\n", retval);
 619                goto unlock_exit;
 620        }
 621        retval = bytes_to_write;
 622
 623unlock_exit:
 624        /* unlock the device */
 625        mutex_unlock(&dev->mutex);
 626
 627exit:
 628        return retval;
 629}
 630
 631/* file operations needed when we register this driver */
 632static const struct file_operations ld_usb_fops = {
 633        .owner =        THIS_MODULE,
 634        .read  =        ld_usb_read,
 635        .write =        ld_usb_write,
 636        .open =         ld_usb_open,
 637        .release =      ld_usb_release,
 638        .poll =         ld_usb_poll,
 639        .llseek =       no_llseek,
 640};
 641
 642/*
 643 * usb class driver info in order to get a minor number from the usb core,
 644 * and to have the device registered with the driver core
 645 */
 646static struct usb_class_driver ld_usb_class = {
 647        .name =         "ldusb%d",
 648        .fops =         &ld_usb_fops,
 649        .minor_base =   USB_LD_MINOR_BASE,
 650};
 651
 652/**
 653 *      ld_usb_probe
 654 *
 655 *      Called by the usb core when a new device is connected that it thinks
 656 *      this driver might be interested in.
 657 */
 658static int ld_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
 659{
 660        struct usb_device *udev = interface_to_usbdev(intf);
 661        struct ld_usb *dev = NULL;
 662        struct usb_host_interface *iface_desc;
 663        struct usb_endpoint_descriptor *endpoint;
 664        char *buffer;
 665        int i;
 666        int retval = -ENOMEM;
 667
 668        /* allocate memory for our device state and initialize it */
 669
 670        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 671        if (dev == NULL) {
 672                dev_err(&intf->dev, "Out of memory\n");
 673                goto exit;
 674        }
 675        mutex_init(&dev->mutex);
 676        spin_lock_init(&dev->rbsl);
 677        dev->intf = intf;
 678        init_waitqueue_head(&dev->read_wait);
 679        init_waitqueue_head(&dev->write_wait);
 680
 681        /* workaround for early firmware versions on fast computers */
 682        if ((le16_to_cpu(udev->descriptor.idVendor) == USB_VENDOR_ID_LD) &&
 683            ((le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_CASSY) ||
 684             (le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_COM3LAB)) &&
 685            (le16_to_cpu(udev->descriptor.bcdDevice) <= 0x103)) {
 686                buffer = kmalloc(256, GFP_KERNEL);
 687                if (buffer == NULL) {
 688                        dev_err(&intf->dev, "Couldn't allocate string buffer\n");
 689                        goto error;
 690                }
 691                /* usb_string makes SETUP+STALL to leave always ControlReadLoop */
 692                usb_string(udev, 255, buffer, 256);
 693                kfree(buffer);
 694        }
 695
 696        iface_desc = intf->cur_altsetting;
 697
 698        /* set up the endpoint information */
 699        for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 700                endpoint = &iface_desc->endpoint[i].desc;
 701
 702                if (usb_endpoint_is_int_in(endpoint))
 703                        dev->interrupt_in_endpoint = endpoint;
 704
 705                if (usb_endpoint_is_int_out(endpoint))
 706                        dev->interrupt_out_endpoint = endpoint;
 707        }
 708        if (dev->interrupt_in_endpoint == NULL) {
 709                dev_err(&intf->dev, "Interrupt in endpoint not found\n");
 710                goto error;
 711        }
 712        if (dev->interrupt_out_endpoint == NULL)
 713                dev_warn(&intf->dev, "Interrupt out endpoint not found (using control endpoint instead)\n");
 714
 715        dev->interrupt_in_endpoint_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
 716        dev->ring_buffer = kmalloc(ring_buffer_size*(sizeof(size_t)+dev->interrupt_in_endpoint_size), GFP_KERNEL);
 717        if (!dev->ring_buffer) {
 718                dev_err(&intf->dev, "Couldn't allocate ring_buffer\n");
 719                goto error;
 720        }
 721        dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 722        if (!dev->interrupt_in_buffer) {
 723                dev_err(&intf->dev, "Couldn't allocate interrupt_in_buffer\n");
 724                goto error;
 725        }
 726        dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 727        if (!dev->interrupt_in_urb) {
 728                dev_err(&intf->dev, "Couldn't allocate interrupt_in_urb\n");
 729                goto error;
 730        }
 731        dev->interrupt_out_endpoint_size = dev->interrupt_out_endpoint ? usb_endpoint_maxp(dev->interrupt_out_endpoint) :
 732                                                                         udev->descriptor.bMaxPacketSize0;
 733        dev->interrupt_out_buffer = kmalloc(write_buffer_size*dev->interrupt_out_endpoint_size, GFP_KERNEL);
 734        if (!dev->interrupt_out_buffer) {
 735                dev_err(&intf->dev, "Couldn't allocate interrupt_out_buffer\n");
 736                goto error;
 737        }
 738        dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 739        if (!dev->interrupt_out_urb) {
 740                dev_err(&intf->dev, "Couldn't allocate interrupt_out_urb\n");
 741                goto error;
 742        }
 743        dev->interrupt_in_interval = min_interrupt_in_interval > dev->interrupt_in_endpoint->bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 744        if (dev->interrupt_out_endpoint)
 745                dev->interrupt_out_interval = min_interrupt_out_interval > dev->interrupt_out_endpoint->bInterval ? min_interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 746
 747        /* we can register the device now, as it is ready */
 748        usb_set_intfdata(intf, dev);
 749
 750        retval = usb_register_dev(intf, &ld_usb_class);
 751        if (retval) {
 752                /* something prevented us from registering this driver */
 753                dev_err(&intf->dev, "Not able to get a minor for this device.\n");
 754                usb_set_intfdata(intf, NULL);
 755                goto error;
 756        }
 757
 758        /* let the user know what node this device is now attached to */
 759        dev_info(&intf->dev, "LD USB Device #%d now attached to major %d minor %d\n",
 760                (intf->minor - USB_LD_MINOR_BASE), USB_MAJOR, intf->minor);
 761
 762exit:
 763        return retval;
 764
 765error:
 766        ld_usb_delete(dev);
 767
 768        return retval;
 769}
 770
 771/**
 772 *      ld_usb_disconnect
 773 *
 774 *      Called by the usb core when the device is removed from the system.
 775 */
 776static void ld_usb_disconnect(struct usb_interface *intf)
 777{
 778        struct ld_usb *dev;
 779        int minor;
 780
 781        dev = usb_get_intfdata(intf);
 782        usb_set_intfdata(intf, NULL);
 783
 784        minor = intf->minor;
 785
 786        /* give back our minor */
 787        usb_deregister_dev(intf, &ld_usb_class);
 788
 789        mutex_lock(&dev->mutex);
 790
 791        /* if the device is not opened, then we clean up right now */
 792        if (!dev->open_count) {
 793                mutex_unlock(&dev->mutex);
 794                ld_usb_delete(dev);
 795        } else {
 796                dev->intf = NULL;
 797                /* wake up pollers */
 798                wake_up_interruptible_all(&dev->read_wait);
 799                wake_up_interruptible_all(&dev->write_wait);
 800                mutex_unlock(&dev->mutex);
 801        }
 802
 803        dev_info(&intf->dev, "LD USB Device #%d now disconnected\n",
 804                 (minor - USB_LD_MINOR_BASE));
 805}
 806
 807/* usb specific object needed to register this driver with the usb subsystem */
 808static struct usb_driver ld_usb_driver = {
 809        .name =         "ldusb",
 810        .probe =        ld_usb_probe,
 811        .disconnect =   ld_usb_disconnect,
 812        .id_table =     ld_usb_table,
 813};
 814
 815module_usb_driver(ld_usb_driver);
 816
 817