LXR linux/drivers/usb/misc/ldusb.c

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Generic USB driver for report based interrupt in/out devices
   4 * like LD Didactic's USB devices. LD Didactic's USB devices are
   5 * HID devices which do not use HID report definitons (they use
   6 * raw interrupt in and our reports only for communication).
   7 *
   8 * This driver uses a ring buffer for time critical reading of
   9 * interrupt in reports and provides read and write methods for
  10 * raw interrupt reports (similar to the Windows HID driver).
  11 * Devices based on the book USB COMPLETE by Jan Axelson may need
  12 * such a compatibility to the Windows HID driver.
  13 *
  14 * Copyright (C) 2005 Michael Hund <mhund@ld-didactic.de>
  15 *
  16 * Derived from Lego USB Tower driver
  17 * Copyright (C) 2003 David Glance <advidgsf@sourceforge.net>
  18 *               2001-2004 Juergen Stuber <starblue@users.sourceforge.net>
  19 */
  20
  21#include <linux/kernel.h>
  22#include <linux/errno.h>
  23#include <linux/slab.h>
  24#include <linux/module.h>
  25#include <linux/mutex.h>
  26
  27#include <linux/uaccess.h>
  28#include <linux/input.h>
  29#include <linux/usb.h>
  30#include <linux/poll.h>
  31
  32/* Define these values to match your devices */
  33#define USB_VENDOR_ID_LD                0x0f11  /* USB Vendor ID of LD Didactic GmbH */
  34#define USB_DEVICE_ID_LD_CASSY          0x1000  /* USB Product ID of CASSY-S modules with 8 bytes endpoint size */
  35#define USB_DEVICE_ID_LD_CASSY2         0x1001  /* USB Product ID of CASSY-S modules with 64 bytes endpoint size */
  36#define USB_DEVICE_ID_LD_POCKETCASSY    0x1010  /* USB Product ID of Pocket-CASSY */
  37#define USB_DEVICE_ID_LD_POCKETCASSY2   0x1011  /* USB Product ID of Pocket-CASSY 2 (reserved) */
  38#define USB_DEVICE_ID_LD_MOBILECASSY    0x1020  /* USB Product ID of Mobile-CASSY */
  39#define USB_DEVICE_ID_LD_MOBILECASSY2   0x1021  /* USB Product ID of Mobile-CASSY 2 (reserved) */
  40#define USB_DEVICE_ID_LD_MICROCASSYVOLTAGE      0x1031  /* USB Product ID of Micro-CASSY Voltage */
  41#define USB_DEVICE_ID_LD_MICROCASSYCURRENT      0x1032  /* USB Product ID of Micro-CASSY Current */
  42#define USB_DEVICE_ID_LD_MICROCASSYTIME         0x1033  /* USB Product ID of Micro-CASSY Time (reserved) */
  43#define USB_DEVICE_ID_LD_MICROCASSYTEMPERATURE  0x1035  /* USB Product ID of Micro-CASSY Temperature */
  44#define USB_DEVICE_ID_LD_MICROCASSYPH           0x1038  /* USB Product ID of Micro-CASSY pH */
  45#define USB_DEVICE_ID_LD_POWERANALYSERCASSY     0x1040  /* USB Product ID of Power Analyser CASSY */
  46#define USB_DEVICE_ID_LD_CONVERTERCONTROLLERCASSY       0x1042  /* USB Product ID of Converter Controller CASSY */
  47#define USB_DEVICE_ID_LD_MACHINETESTCASSY       0x1043  /* USB Product ID of Machine Test CASSY */
  48#define USB_DEVICE_ID_LD_JWM            0x1080  /* USB Product ID of Joule and Wattmeter */
  49#define USB_DEVICE_ID_LD_DMMP           0x1081  /* USB Product ID of Digital Multimeter P (reserved) */
  50#define USB_DEVICE_ID_LD_UMIP           0x1090  /* USB Product ID of UMI P */
  51#define USB_DEVICE_ID_LD_UMIC           0x10A0  /* USB Product ID of UMI C */
  52#define USB_DEVICE_ID_LD_UMIB           0x10B0  /* USB Product ID of UMI B */
  53#define USB_DEVICE_ID_LD_XRAY           0x1100  /* USB Product ID of X-Ray Apparatus 55481 */
  54#define USB_DEVICE_ID_LD_XRAY2          0x1101  /* USB Product ID of X-Ray Apparatus 554800 */
  55#define USB_DEVICE_ID_LD_XRAYCT         0x1110  /* USB Product ID of X-Ray Apparatus CT 554821*/
  56#define USB_DEVICE_ID_LD_VIDEOCOM       0x1200  /* USB Product ID of VideoCom */
  57#define USB_DEVICE_ID_LD_MOTOR          0x1210  /* USB Product ID of Motor (reserved) */
  58#define USB_DEVICE_ID_LD_COM3LAB        0x2000  /* USB Product ID of COM3LAB */
  59#define USB_DEVICE_ID_LD_TELEPORT       0x2010  /* USB Product ID of Terminal Adapter */
  60#define USB_DEVICE_ID_LD_NETWORKANALYSER 0x2020 /* USB Product ID of Network Analyser */
  61#define USB_DEVICE_ID_LD_POWERCONTROL   0x2030  /* USB Product ID of Converter Control Unit */
  62#define USB_DEVICE_ID_LD_MACHINETEST    0x2040  /* USB Product ID of Machine Test System */
  63#define USB_DEVICE_ID_LD_MOSTANALYSER   0x2050  /* USB Product ID of MOST Protocol Analyser */
  64#define USB_DEVICE_ID_LD_MOSTANALYSER2  0x2051  /* USB Product ID of MOST Protocol Analyser 2 */
  65#define USB_DEVICE_ID_LD_ABSESP         0x2060  /* USB Product ID of ABS ESP */
  66#define USB_DEVICE_ID_LD_AUTODATABUS    0x2070  /* USB Product ID of Automotive Data Buses */
  67#define USB_DEVICE_ID_LD_MCT            0x2080  /* USB Product ID of Microcontroller technique */
  68#define USB_DEVICE_ID_LD_HYBRID         0x2090  /* USB Product ID of Automotive Hybrid */
  69#define USB_DEVICE_ID_LD_HEATCONTROL    0x20A0  /* USB Product ID of Heat control */
  70
  71#ifdef CONFIG_USB_DYNAMIC_MINORS
  72#define USB_LD_MINOR_BASE       0
  73#else
  74#define USB_LD_MINOR_BASE       176
  75#endif
  76
  77/* table of devices that work with this driver */
  78static const struct usb_device_id ld_usb_table[] = {
  79        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CASSY) },
  80        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CASSY2) },
  81        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POCKETCASSY) },
  82        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POCKETCASSY2) },
  83        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOBILECASSY) },
  84        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOBILECASSY2) },
  85        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYVOLTAGE) },
  86        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYCURRENT) },
  87        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYTIME) },
  88        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYTEMPERATURE) },
  89        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYPH) },
  90        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POWERANALYSERCASSY) },
  91        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CONVERTERCONTROLLERCASSY) },
  92        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MACHINETESTCASSY) },
  93        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_JWM) },
  94        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_DMMP) },
  95        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIP) },
  96        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIC) },
  97        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIB) },
  98        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_XRAY) },
  99        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_XRAY2) },
 100        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_VIDEOCOM) },
 101        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOTOR) },
 102        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_COM3LAB) },
 103        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_TELEPORT) },
 104        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_NETWORKANALYSER) },
 105        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POWERCONTROL) },
 106        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MACHINETEST) },
 107        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOSTANALYSER) },
 108        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOSTANALYSER2) },
 109        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_ABSESP) },
 110        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_AUTODATABUS) },
 111        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MCT) },
 112        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_HYBRID) },
 113        { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_HEATCONTROL) },
 114        { }                                     /* Terminating entry */
 115};
 116MODULE_DEVICE_TABLE(usb, ld_usb_table);
 117MODULE_AUTHOR("Michael Hund <mhund@ld-didactic.de>");
 118MODULE_DESCRIPTION("LD USB Driver");
 119MODULE_LICENSE("GPL");
 120MODULE_SUPPORTED_DEVICE("LD USB Devices");
 121
 122/* All interrupt in transfers are collected in a ring buffer to
 123 * avoid racing conditions and get better performance of the driver.
 124 */
 125static int ring_buffer_size = 128;
 126module_param(ring_buffer_size, int, 0000);
 127MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size in reports");
 128
 129/* The write_buffer can contain more than one interrupt out transfer.
 130 */
 131static int write_buffer_size = 10;
 132module_param(write_buffer_size, int, 0000);
 133MODULE_PARM_DESC(write_buffer_size, "Write buffer size in reports");
 134
 135/* As of kernel version 2.6.4 ehci-hcd uses an
 136 * "only one interrupt transfer per frame" shortcut
 137 * to simplify the scheduling of periodic transfers.
 138 * This conflicts with our standard 1ms intervals for in and out URBs.
 139 * We use default intervals of 2ms for in and 2ms for out transfers,
 140 * which should be fast enough.
 141 * Increase the interval to allow more devices that do interrupt transfers,
 142 * or set to 1 to use the standard interval from the endpoint descriptors.
 143 */
 144static int min_interrupt_in_interval = 2;
 145module_param(min_interrupt_in_interval, int, 0000);
 146MODULE_PARM_DESC(min_interrupt_in_interval, "Minimum interrupt in interval in ms");
 147
 148static int min_interrupt_out_interval = 2;
 149module_param(min_interrupt_out_interval, int, 0000);
 150MODULE_PARM_DESC(min_interrupt_out_interval, "Minimum interrupt out interval in ms");
 151
 152/* Structure to hold all of our device specific stuff */
 153struct ld_usb {
 154        struct mutex            mutex;          /* locks this structure */
 155        struct usb_interface    *intf;          /* save off the usb interface pointer */
 156        unsigned long           disconnected:1;
 157
 158        int                     open_count;     /* number of times this port has been opened */
 159
 160        char                    *ring_buffer;
 161        unsigned int            ring_head;
 162        unsigned int            ring_tail;
 163
 164        wait_queue_head_t       read_wait;
 165        wait_queue_head_t       write_wait;
 166
 167        char                    *interrupt_in_buffer;
 168        struct usb_endpoint_descriptor *interrupt_in_endpoint;
 169        struct urb              *interrupt_in_urb;
 170        int                     interrupt_in_interval;
 171        size_t                  interrupt_in_endpoint_size;
 172        int                     interrupt_in_running;
 173        int                     interrupt_in_done;
 174        int                     buffer_overflow;
 175        spinlock_t              rbsl;
 176
 177        char                    *interrupt_out_buffer;
 178        struct usb_endpoint_descriptor *interrupt_out_endpoint;
 179        struct urb              *interrupt_out_urb;
 180        int                     interrupt_out_interval;
 181        size_t                  interrupt_out_endpoint_size;
 182        int                     interrupt_out_busy;
 183};
 184
 185static struct usb_driver ld_usb_driver;
 186
 187/*
 188 *      ld_usb_abort_transfers
 189 *      aborts transfers and frees associated data structures
 190 */
 191static void ld_usb_abort_transfers(struct ld_usb *dev)
 192{
 193        /* shutdown transfer */
 194        if (dev->interrupt_in_running) {
 195                dev->interrupt_in_running = 0;
 196                usb_kill_urb(dev->interrupt_in_urb);
 197        }
 198        if (dev->interrupt_out_busy)
 199                usb_kill_urb(dev->interrupt_out_urb);
 200}
 201
 202/*
 203 *      ld_usb_delete
 204 */
 205static void ld_usb_delete(struct ld_usb *dev)
 206{
 207        /* free data structures */
 208        usb_free_urb(dev->interrupt_in_urb);
 209        usb_free_urb(dev->interrupt_out_urb);
 210        kfree(dev->ring_buffer);
 211        kfree(dev->interrupt_in_buffer);
 212        kfree(dev->interrupt_out_buffer);
 213        kfree(dev);
 214}
 215
 216/*
 217 *      ld_usb_interrupt_in_callback
 218 */
 219static void ld_usb_interrupt_in_callback(struct urb *urb)
 220{
 221        struct ld_usb *dev = urb->context;
 222        size_t *actual_buffer;
 223        unsigned int next_ring_head;
 224        int status = urb->status;
 225        unsigned long flags;
 226        int retval;
 227
 228        if (status) {
 229                if (status == -ENOENT ||
 230                    status == -ECONNRESET ||
 231                    status == -ESHUTDOWN) {
 232                        goto exit;
 233                } else {
 234                        dev_dbg(&dev->intf->dev,
 235                                "%s: nonzero status received: %d\n", __func__,
 236                                status);
 237                        spin_lock_irqsave(&dev->rbsl, flags);
 238                        goto resubmit; /* maybe we can recover */
 239                }
 240        }
 241
 242        spin_lock_irqsave(&dev->rbsl, flags);
 243        if (urb->actual_length > 0) {
 244                next_ring_head = (dev->ring_head+1) % ring_buffer_size;
 245                if (next_ring_head != dev->ring_tail) {
 246                        actual_buffer = (size_t *)(dev->ring_buffer + dev->ring_head * (sizeof(size_t)+dev->interrupt_in_endpoint_size));
 247                        /* actual_buffer gets urb->actual_length + interrupt_in_buffer */
 248                        *actual_buffer = urb->actual_length;
 249                        memcpy(actual_buffer+1, dev->interrupt_in_buffer, urb->actual_length);
 250                        dev->ring_head = next_ring_head;
 251                        dev_dbg(&dev->intf->dev, "%s: received %d bytes\n",
 252                                __func__, urb->actual_length);
 253                } else {
 254                        dev_warn(&dev->intf->dev,
 255                                 "Ring buffer overflow, %d bytes dropped\n",
 256                                 urb->actual_length);
 257                        dev->buffer_overflow = 1;
 258                }
 259        }
 260
 261resubmit:
 262        /* resubmit if we're still running */
 263        if (dev->interrupt_in_running && !dev->buffer_overflow) {
 264                retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
 265                if (retval) {
 266                        dev_err(&dev->intf->dev,
 267                                "usb_submit_urb failed (%d)\n", retval);
 268                        dev->buffer_overflow = 1;
 269                }
 270        }
 271        spin_unlock_irqrestore(&dev->rbsl, flags);
 272exit:
 273        dev->interrupt_in_done = 1;
 274        wake_up_interruptible(&dev->read_wait);
 275}
 276
 277/*
 278 *      ld_usb_interrupt_out_callback
 279 */
 280static void ld_usb_interrupt_out_callback(struct urb *urb)
 281{
 282        struct ld_usb *dev = urb->context;
 283        int status = urb->status;
 284
 285        /* sync/async unlink faults aren't errors */
 286        if (status && !(status == -ENOENT ||
 287                        status == -ECONNRESET ||
 288                        status == -ESHUTDOWN))
 289                dev_dbg(&dev->intf->dev,
 290                        "%s - nonzero write interrupt status received: %d\n",
 291                        __func__, status);
 292
 293        dev->interrupt_out_busy = 0;
 294        wake_up_interruptible(&dev->write_wait);
 295}
 296
 297/*
 298 *      ld_usb_open
 299 */
 300static int ld_usb_open(struct inode *inode, struct file *file)
 301{
 302        struct ld_usb *dev;
 303        int subminor;
 304        int retval;
 305        struct usb_interface *interface;
 306
 307        stream_open(inode, file);
 308        subminor = iminor(inode);
 309
 310        interface = usb_find_interface(&ld_usb_driver, subminor);
 311
 312        if (!interface) {
 313                printk(KERN_ERR "%s - error, can't find device for minor %d\n",
 314                       __func__, subminor);
 315                return -ENODEV;
 316        }
 317
 318        dev = usb_get_intfdata(interface);
 319
 320        if (!dev)
 321                return -ENODEV;
 322
 323        /* lock this device */
 324        if (mutex_lock_interruptible(&dev->mutex))
 325                return -ERESTARTSYS;
 326
 327        /* allow opening only once */
 328        if (dev->open_count) {
 329                retval = -EBUSY;
 330                goto unlock_exit;
 331        }
 332        dev->open_count = 1;
 333
 334        /* initialize in direction */
 335        dev->ring_head = 0;
 336        dev->ring_tail = 0;
 337        dev->buffer_overflow = 0;
 338        usb_fill_int_urb(dev->interrupt_in_urb,
 339                         interface_to_usbdev(interface),
 340                         usb_rcvintpipe(interface_to_usbdev(interface),
 341                                        dev->interrupt_in_endpoint->bEndpointAddress),
 342                         dev->interrupt_in_buffer,
 343                         dev->interrupt_in_endpoint_size,
 344                         ld_usb_interrupt_in_callback,
 345                         dev,
 346                         dev->interrupt_in_interval);
 347
 348        dev->interrupt_in_running = 1;
 349        dev->interrupt_in_done = 0;
 350
 351        retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 352        if (retval) {
 353                dev_err(&interface->dev, "Couldn't submit interrupt_in_urb %d\n", retval);
 354                dev->interrupt_in_running = 0;
 355                dev->open_count = 0;
 356                goto unlock_exit;
 357        }
 358
 359        /* save device in the file's private structure */
 360        file->private_data = dev;
 361
 362unlock_exit:
 363        mutex_unlock(&dev->mutex);
 364
 365        return retval;
 366}
 367
 368/*
 369 *      ld_usb_release
 370 */
 371static int ld_usb_release(struct inode *inode, struct file *file)
 372{
 373        struct ld_usb *dev;
 374        int retval = 0;
 375
 376        dev = file->private_data;
 377
 378        if (dev == NULL) {
 379                retval = -ENODEV;
 380                goto exit;
 381        }
 382
 383        mutex_lock(&dev->mutex);
 384
 385        if (dev->open_count != 1) {
 386                retval = -ENODEV;
 387                goto unlock_exit;
 388        }
 389        if (dev->disconnected) {
 390                /* the device was unplugged before the file was released */
 391                mutex_unlock(&dev->mutex);
 392                /* unlock here as ld_usb_delete frees dev */
 393                ld_usb_delete(dev);
 394                goto exit;
 395        }
 396
 397        /* wait until write transfer is finished */
 398        if (dev->interrupt_out_busy)
 399                wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 400        ld_usb_abort_transfers(dev);
 401        dev->open_count = 0;
 402
 403unlock_exit:
 404        mutex_unlock(&dev->mutex);
 405
 406exit:
 407        return retval;
 408}
 409
 410/*
 411 *      ld_usb_poll
 412 */
 413static __poll_t ld_usb_poll(struct file *file, poll_table *wait)
 414{
 415        struct ld_usb *dev;
 416        __poll_t mask = 0;
 417
 418        dev = file->private_data;
 419
 420        if (dev->disconnected)
 421                return EPOLLERR | EPOLLHUP;
 422
 423        poll_wait(file, &dev->read_wait, wait);
 424        poll_wait(file, &dev->write_wait, wait);
 425
 426        if (dev->ring_head != dev->ring_tail)
 427                mask |= EPOLLIN | EPOLLRDNORM;
 428        if (!dev->interrupt_out_busy)
 429                mask |= EPOLLOUT | EPOLLWRNORM;
 430
 431        return mask;
 432}
 433
 434/*
 435 *      ld_usb_read
 436 */
 437static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
 438                           loff_t *ppos)
 439{
 440        struct ld_usb *dev;
 441        size_t *actual_buffer;
 442        size_t bytes_to_read;
 443        int retval = 0;
 444        int rv;
 445
 446        dev = file->private_data;
 447
 448        /* verify that we actually have some data to read */
 449        if (count == 0)
 450                goto exit;
 451
 452        /* lock this object */
 453        if (mutex_lock_interruptible(&dev->mutex)) {
 454                retval = -ERESTARTSYS;
 455                goto exit;
 456        }
 457
 458        /* verify that the device wasn't unplugged */
 459        if (dev->disconnected) {
 460                retval = -ENODEV;
 461                printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
 462                goto unlock_exit;
 463        }
 464
 465        /* wait for data */
 466        spin_lock_irq(&dev->rbsl);
 467        while (dev->ring_head == dev->ring_tail) {
 468                dev->interrupt_in_done = 0;
 469                spin_unlock_irq(&dev->rbsl);
 470                if (file->f_flags & O_NONBLOCK) {
 471                        retval = -EAGAIN;
 472                        goto unlock_exit;
 473                }
 474                retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
 475                if (retval < 0)
 476                        goto unlock_exit;
 477
 478                spin_lock_irq(&dev->rbsl);
 479        }
 480        spin_unlock_irq(&dev->rbsl);
 481
 482        /* actual_buffer contains actual_length + interrupt_in_buffer */
 483        actual_buffer = (size_t *)(dev->ring_buffer + dev->ring_tail * (sizeof(size_t)+dev->interrupt_in_endpoint_size));
 484        if (*actual_buffer > dev->interrupt_in_endpoint_size) {
 485                retval = -EIO;
 486                goto unlock_exit;
 487        }
 488        bytes_to_read = min(count, *actual_buffer);
 489        if (bytes_to_read < *actual_buffer)
 490                dev_warn(&dev->intf->dev, "Read buffer overflow, %zu bytes dropped\n",
 491                         *actual_buffer-bytes_to_read);
 492
 493        /* copy one interrupt_in_buffer from ring_buffer into userspace */
 494        if (copy_to_user(buffer, actual_buffer+1, bytes_to_read)) {
 495                retval = -EFAULT;
 496                goto unlock_exit;
 497        }
 498        retval = bytes_to_read;
 499
 500        spin_lock_irq(&dev->rbsl);
 501        dev->ring_tail = (dev->ring_tail + 1) % ring_buffer_size;
 502
 503        if (dev->buffer_overflow) {
 504                dev->buffer_overflow = 0;
 505                spin_unlock_irq(&dev->rbsl);
 506                rv = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 507                if (rv < 0)
 508                        dev->buffer_overflow = 1;
 509        } else {
 510                spin_unlock_irq(&dev->rbsl);
 511        }
 512
 513unlock_exit:
 514        /* unlock the device */
 515        mutex_unlock(&dev->mutex);
 516
 517exit:
 518        return retval;
 519}
 520
 521/*
 522 *      ld_usb_write
 523 */
 524static ssize_t ld_usb_write(struct file *file, const char __user *buffer,
 525                            size_t count, loff_t *ppos)
 526{
 527        struct ld_usb *dev;
 528        size_t bytes_to_write;
 529        int retval = 0;
 530
 531        dev = file->private_data;
 532
 533        /* verify that we actually have some data to write */
 534        if (count == 0)
 535                goto exit;
 536
 537        /* lock this object */
 538        if (mutex_lock_interruptible(&dev->mutex)) {
 539                retval = -ERESTARTSYS;
 540                goto exit;
 541        }
 542
 543        /* verify that the device wasn't unplugged */
 544        if (dev->disconnected) {
 545                retval = -ENODEV;
 546                printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
 547                goto unlock_exit;
 548        }
 549
 550        /* wait until previous transfer is finished */
 551        if (dev->interrupt_out_busy) {
 552                if (file->f_flags & O_NONBLOCK) {
 553                        retval = -EAGAIN;
 554                        goto unlock_exit;
 555                }
 556                retval = wait_event_interruptible(dev->write_wait, !dev->interrupt_out_busy);
 557                if (retval < 0) {
 558                        goto unlock_exit;
 559                }
 560        }
 561
 562        /* write the data into interrupt_out_buffer from userspace */
 563        bytes_to_write = min(count, write_buffer_size*dev->interrupt_out_endpoint_size);
 564        if (bytes_to_write < count)
 565                dev_warn(&dev->intf->dev, "Write buffer overflow, %zu bytes dropped\n",
 566                        count - bytes_to_write);
 567        dev_dbg(&dev->intf->dev, "%s: count = %zu, bytes_to_write = %zu\n",
 568                __func__, count, bytes_to_write);
 569
 570        if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 571                retval = -EFAULT;
 572                goto unlock_exit;
 573        }
 574
 575        if (dev->interrupt_out_endpoint == NULL) {
 576                /* try HID_REQ_SET_REPORT=9 on control_endpoint instead of interrupt_out_endpoint */
 577                retval = usb_control_msg(interface_to_usbdev(dev->intf),
 578                                         usb_sndctrlpipe(interface_to_usbdev(dev->intf), 0),
 579                                         9,
 580                                         USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
 581                                         1 << 8, 0,
 582                                         dev->interrupt_out_buffer,
 583                                         bytes_to_write,
 584                                         USB_CTRL_SET_TIMEOUT);
 585                if (retval < 0)
 586                        dev_err(&dev->intf->dev,
 587                                "Couldn't submit HID_REQ_SET_REPORT %d\n",
 588                                retval);
 589                goto unlock_exit;
 590        }
 591
 592        /* send off the urb */
 593        usb_fill_int_urb(dev->interrupt_out_urb,
 594                         interface_to_usbdev(dev->intf),
 595                         usb_sndintpipe(interface_to_usbdev(dev->intf),
 596                                        dev->interrupt_out_endpoint->bEndpointAddress),
 597                         dev->interrupt_out_buffer,
 598                         bytes_to_write,
 599                         ld_usb_interrupt_out_callback,
 600                         dev,
 601                         dev->interrupt_out_interval);
 602
 603        dev->interrupt_out_busy = 1;
 604        wmb();
 605
 606        retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 607        if (retval) {
 608                dev->interrupt_out_busy = 0;
 609                dev_err(&dev->intf->dev,
 610                        "Couldn't submit interrupt_out_urb %d\n", retval);
 611                goto unlock_exit;
 612        }
 613        retval = bytes_to_write;
 614
 615unlock_exit:
 616        /* unlock the device */
 617        mutex_unlock(&dev->mutex);
 618
 619exit:
 620        return retval;
 621}
 622
 623/* file operations needed when we register this driver */
 624static const struct file_operations ld_usb_fops = {
 625        .owner =        THIS_MODULE,
 626        .read  =        ld_usb_read,
 627        .write =        ld_usb_write,
 628        .open =         ld_usb_open,
 629        .release =      ld_usb_release,
 630        .poll =         ld_usb_poll,
 631        .llseek =       no_llseek,
 632};
 633
 634/*
 635 * usb class driver info in order to get a minor number from the usb core,
 636 * and to have the device registered with the driver core
 637 */
 638static struct usb_class_driver ld_usb_class = {
 639        .name =         "ldusb%d",
 640        .fops =         &ld_usb_fops,
 641        .minor_base =   USB_LD_MINOR_BASE,
 642};
 643
 644/*
 645 *      ld_usb_probe
 646 *
 647 *      Called by the usb core when a new device is connected that it thinks
 648 *      this driver might be interested in.
 649 */
 650static int ld_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
 651{
 652        struct usb_device *udev = interface_to_usbdev(intf);
 653        struct ld_usb *dev = NULL;
 654        struct usb_host_interface *iface_desc;
 655        char *buffer;
 656        int retval = -ENOMEM;
 657        int res;
 658
 659        /* allocate memory for our device state and initialize it */
 660
 661        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 662        if (!dev)
 663                goto exit;
 664        mutex_init(&dev->mutex);
 665        spin_lock_init(&dev->rbsl);
 666        dev->intf = intf;
 667        init_waitqueue_head(&dev->read_wait);
 668        init_waitqueue_head(&dev->write_wait);
 669
 670        /* workaround for early firmware versions on fast computers */
 671        if ((le16_to_cpu(udev->descriptor.idVendor) == USB_VENDOR_ID_LD) &&
 672            ((le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_CASSY) ||
 673             (le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_COM3LAB)) &&
 674            (le16_to_cpu(udev->descriptor.bcdDevice) <= 0x103)) {
 675                buffer = kmalloc(256, GFP_KERNEL);
 676                if (!buffer)
 677                        goto error;
 678                /* usb_string makes SETUP+STALL to leave always ControlReadLoop */
 679                usb_string(udev, 255, buffer, 256);
 680                kfree(buffer);
 681        }
 682
 683        iface_desc = intf->cur_altsetting;
 684
 685        res = usb_find_last_int_in_endpoint(iface_desc,
 686                        &dev->interrupt_in_endpoint);
 687        if (res) {
 688                dev_err(&intf->dev, "Interrupt in endpoint not found\n");
 689                retval = res;
 690                goto error;
 691        }
 692
 693        res = usb_find_last_int_out_endpoint(iface_desc,
 694                        &dev->interrupt_out_endpoint);
 695        if (res)
 696                dev_warn(&intf->dev, "Interrupt out endpoint not found (using control endpoint instead)\n");
 697
 698        dev->interrupt_in_endpoint_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
 699        dev->ring_buffer = kcalloc(ring_buffer_size,
 700                        sizeof(size_t) + dev->interrupt_in_endpoint_size,
 701                        GFP_KERNEL);
 702        if (!dev->ring_buffer)
 703                goto error;
 704        dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 705        if (!dev->interrupt_in_buffer)
 706                goto error;
 707        dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 708        if (!dev->interrupt_in_urb)
 709                goto error;
 710        dev->interrupt_out_endpoint_size = dev->interrupt_out_endpoint ? usb_endpoint_maxp(dev->interrupt_out_endpoint) :
 711                                                                         udev->descriptor.bMaxPacketSize0;
 712        dev->interrupt_out_buffer =
 713                kmalloc_array(write_buffer_size,
 714                              dev->interrupt_out_endpoint_size, GFP_KERNEL);
 715        if (!dev->interrupt_out_buffer)
 716                goto error;
 717        dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 718        if (!dev->interrupt_out_urb)
 719                goto error;
 720        dev->interrupt_in_interval = min_interrupt_in_interval > dev->interrupt_in_endpoint->bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 721        if (dev->interrupt_out_endpoint)
 722                dev->interrupt_out_interval = min_interrupt_out_interval > dev->interrupt_out_endpoint->bInterval ? min_interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 723
 724        /* we can register the device now, as it is ready */
 725        usb_set_intfdata(intf, dev);
 726
 727        retval = usb_register_dev(intf, &ld_usb_class);
 728        if (retval) {
 729                /* something prevented us from registering this driver */
 730                dev_err(&intf->dev, "Not able to get a minor for this device.\n");
 731                usb_set_intfdata(intf, NULL);
 732                goto error;
 733        }
 734
 735        /* let the user know what node this device is now attached to */
 736        dev_info(&intf->dev, "LD USB Device #%d now attached to major %d minor %d\n",
 737                (intf->minor - USB_LD_MINOR_BASE), USB_MAJOR, intf->minor);
 738
 739exit:
 740        return retval;
 741
 742error:
 743        ld_usb_delete(dev);
 744
 745        return retval;
 746}
 747
 748/*
 749 *      ld_usb_disconnect
 750 *
 751 *      Called by the usb core when the device is removed from the system.
 752 */
 753static void ld_usb_disconnect(struct usb_interface *intf)
 754{
 755        struct ld_usb *dev;
 756        int minor;
 757
 758        dev = usb_get_intfdata(intf);
 759        usb_set_intfdata(intf, NULL);
 760
 761        minor = intf->minor;
 762
 763        /* give back our minor */
 764        usb_deregister_dev(intf, &ld_usb_class);
 765
 766        usb_poison_urb(dev->interrupt_in_urb);
 767        usb_poison_urb(dev->interrupt_out_urb);
 768
 769        mutex_lock(&dev->mutex);
 770
 771        /* if the device is not opened, then we clean up right now */
 772        if (!dev->open_count) {
 773                mutex_unlock(&dev->mutex);
 774                ld_usb_delete(dev);
 775        } else {
 776                dev->disconnected = 1;
 777                /* wake up pollers */
 778                wake_up_interruptible_all(&dev->read_wait);
 779                wake_up_interruptible_all(&dev->write_wait);
 780                mutex_unlock(&dev->mutex);
 781        }
 782
 783        dev_info(&intf->dev, "LD USB Device #%d now disconnected\n",
 784                 (minor - USB_LD_MINOR_BASE));
 785}
 786
 787/* usb specific object needed to register this driver with the usb subsystem */
 788static struct usb_driver ld_usb_driver = {
 789        .name =         "ldusb",
 790        .probe =        ld_usb_probe,
 791        .disconnect =   ld_usb_disconnect,
 792        .id_table =     ld_usb_table,
 793};
 794
 795module_usb_driver(ld_usb_driver);
 796
 797