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
 157        int                     open_count;     /* number of times this port has been opened */
 158
 159        char                    *ring_buffer;
 160        unsigned int            ring_head;
 161        unsigned int            ring_tail;
 162
 163        wait_queue_head_t       read_wait;
 164        wait_queue_head_t       write_wait;
 165
 166        char                    *interrupt_in_buffer;
 167        struct usb_endpoint_descriptor *interrupt_in_endpoint;
 168        struct urb              *interrupt_in_urb;
 169        int                     interrupt_in_interval;
 170        size_t                  interrupt_in_endpoint_size;
 171        int                     interrupt_in_running;
 172        int                     interrupt_in_done;
 173        int                     buffer_overflow;
 174        spinlock_t              rbsl;
 175
 176        char                    *interrupt_out_buffer;
 177        struct usb_endpoint_descriptor *interrupt_out_endpoint;
 178        struct urb              *interrupt_out_urb;
 179        int                     interrupt_out_interval;
 180        size_t                  interrupt_out_endpoint_size;
 181        int                     interrupt_out_busy;
 182};
 183
 184static struct usb_driver ld_usb_driver;
 185
 186/**
 187 *      ld_usb_abort_transfers
 188 *      aborts transfers and frees associated data structures
 189 */
 190static void ld_usb_abort_transfers(struct ld_usb *dev)
 191{
 192        /* shutdown transfer */
 193        if (dev->interrupt_in_running) {
 194                dev->interrupt_in_running = 0;
 195                if (dev->intf)
 196                        usb_kill_urb(dev->interrupt_in_urb);
 197        }
 198        if (dev->interrupt_out_busy)
 199                if (dev->intf)
 200                        usb_kill_urb(dev->interrupt_out_urb);
 201}
 202
 203/**
 204 *      ld_usb_delete
 205 */
 206static void ld_usb_delete(struct ld_usb *dev)
 207{
 208        ld_usb_abort_transfers(dev);
 209
 210        /* free data structures */
 211        usb_free_urb(dev->interrupt_in_urb);
 212        usb_free_urb(dev->interrupt_out_urb);
 213        kfree(dev->ring_buffer);
 214        kfree(dev->interrupt_in_buffer);
 215        kfree(dev->interrupt_out_buffer);
 216        kfree(dev);
 217}
 218
 219/**
 220 *      ld_usb_interrupt_in_callback
 221 */
 222static void ld_usb_interrupt_in_callback(struct urb *urb)
 223{
 224        struct ld_usb *dev = urb->context;
 225        size_t *actual_buffer;
 226        unsigned int next_ring_head;
 227        int status = urb->status;
 228        int retval;
 229
 230        if (status) {
 231                if (status == -ENOENT ||
 232                    status == -ECONNRESET ||
 233                    status == -ESHUTDOWN) {
 234                        goto exit;
 235                } else {
 236                        dev_dbg(&dev->intf->dev,
 237                                "%s: nonzero status received: %d\n", __func__,
 238                                status);
 239                        spin_lock(&dev->rbsl);
 240                        goto resubmit; /* maybe we can recover */
 241                }
 242        }
 243
 244        spin_lock(&dev->rbsl);
 245        if (urb->actual_length > 0) {
 246                next_ring_head = (dev->ring_head+1) % ring_buffer_size;
 247                if (next_ring_head != dev->ring_tail) {
 248                        actual_buffer = (size_t *)(dev->ring_buffer + dev->ring_head * (sizeof(size_t)+dev->interrupt_in_endpoint_size));
 249                        /* actual_buffer gets urb->actual_length + interrupt_in_buffer */
 250                        *actual_buffer = urb->actual_length;
 251                        memcpy(actual_buffer+1, dev->interrupt_in_buffer, urb->actual_length);
 252                        dev->ring_head = next_ring_head;
 253                        dev_dbg(&dev->intf->dev, "%s: received %d bytes\n",
 254                                __func__, urb->actual_length);
 255                } else {
 256                        dev_warn(&dev->intf->dev,
 257                                 "Ring buffer overflow, %d bytes dropped\n",
 258                                 urb->actual_length);
 259                        dev->buffer_overflow = 1;
 260                }
 261        }
 262
 263resubmit:
 264        /* resubmit if we're still running */
 265        if (dev->interrupt_in_running && !dev->buffer_overflow && dev->intf) {
 266                retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
 267                if (retval) {
 268                        dev_err(&dev->intf->dev,
 269                                "usb_submit_urb failed (%d)\n", retval);
 270                        dev->buffer_overflow = 1;
 271                }
 272        }
 273        spin_unlock(&dev->rbsl);
 274exit:
 275        dev->interrupt_in_done = 1;
 276        wake_up_interruptible(&dev->read_wait);
 277}
 278
 279/**
 280 *      ld_usb_interrupt_out_callback
 281 */
 282static void ld_usb_interrupt_out_callback(struct urb *urb)
 283{
 284        struct ld_usb *dev = urb->context;
 285        int status = urb->status;
 286
 287        /* sync/async unlink faults aren't errors */
 288        if (status && !(status == -ENOENT ||
 289                        status == -ECONNRESET ||
 290                        status == -ESHUTDOWN))
 291                dev_dbg(&dev->intf->dev,
 292                        "%s - nonzero write interrupt status received: %d\n",
 293                        __func__, status);
 294
 295        dev->interrupt_out_busy = 0;
 296        wake_up_interruptible(&dev->write_wait);
 297}
 298
 299/**
 300 *      ld_usb_open
 301 */
 302static int ld_usb_open(struct inode *inode, struct file *file)
 303{
 304        struct ld_usb *dev;
 305        int subminor;
 306        int retval;
 307        struct usb_interface *interface;
 308
 309        nonseekable_open(inode, file);
 310        subminor = iminor(inode);
 311
 312        interface = usb_find_interface(&ld_usb_driver, subminor);
 313
 314        if (!interface) {
 315                printk(KERN_ERR "%s - error, can't find device for minor %d\n",
 316                       __func__, subminor);
 317                return -ENODEV;
 318        }
 319
 320        dev = usb_get_intfdata(interface);
 321
 322        if (!dev)
 323                return -ENODEV;
 324
 325        /* lock this device */
 326        if (mutex_lock_interruptible(&dev->mutex))
 327                return -ERESTARTSYS;
 328
 329        /* allow opening only once */
 330        if (dev->open_count) {
 331                retval = -EBUSY;
 332                goto unlock_exit;
 333        }
 334        dev->open_count = 1;
 335
 336        /* initialize in direction */
 337        dev->ring_head = 0;
 338        dev->ring_tail = 0;
 339        dev->buffer_overflow = 0;
 340        usb_fill_int_urb(dev->interrupt_in_urb,
 341                         interface_to_usbdev(interface),
 342                         usb_rcvintpipe(interface_to_usbdev(interface),
 343                                        dev->interrupt_in_endpoint->bEndpointAddress),
 344                         dev->interrupt_in_buffer,
 345                         dev->interrupt_in_endpoint_size,
 346                         ld_usb_interrupt_in_callback,
 347                         dev,
 348                         dev->interrupt_in_interval);
 349
 350        dev->interrupt_in_running = 1;
 351        dev->interrupt_in_done = 0;
 352
 353        retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 354        if (retval) {
 355                dev_err(&interface->dev, "Couldn't submit interrupt_in_urb %d\n", retval);
 356                dev->interrupt_in_running = 0;
 357                dev->open_count = 0;
 358                goto unlock_exit;
 359        }
 360
 361        /* save device in the file's private structure */
 362        file->private_data = dev;
 363
 364unlock_exit:
 365        mutex_unlock(&dev->mutex);
 366
 367        return retval;
 368}
 369
 370/**
 371 *      ld_usb_release
 372 */
 373static int ld_usb_release(struct inode *inode, struct file *file)
 374{
 375        struct ld_usb *dev;
 376        int retval = 0;
 377
 378        dev = file->private_data;
 379
 380        if (dev == NULL) {
 381                retval = -ENODEV;
 382                goto exit;
 383        }
 384
 385        if (mutex_lock_interruptible(&dev->mutex)) {
 386                retval = -ERESTARTSYS;
 387                goto exit;
 388        }
 389
 390        if (dev->open_count != 1) {
 391                retval = -ENODEV;
 392                goto unlock_exit;
 393        }
 394        if (dev->intf == NULL) {
 395                /* the device was unplugged before the file was released */
 396                mutex_unlock(&dev->mutex);
 397                /* unlock here as ld_usb_delete frees dev */
 398                ld_usb_delete(dev);
 399                goto exit;
 400        }
 401
 402        /* wait until write transfer is finished */
 403        if (dev->interrupt_out_busy)
 404                wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 405        ld_usb_abort_transfers(dev);
 406        dev->open_count = 0;
 407
 408unlock_exit:
 409        mutex_unlock(&dev->mutex);
 410
 411exit:
 412        return retval;
 413}
 414
 415/**
 416 *      ld_usb_poll
 417 */
 418static __poll_t ld_usb_poll(struct file *file, poll_table *wait)
 419{
 420        struct ld_usb *dev;
 421        __poll_t mask = 0;
 422
 423        dev = file->private_data;
 424
 425        if (!dev->intf)
 426                return EPOLLERR | EPOLLHUP;
 427
 428        poll_wait(file, &dev->read_wait, wait);
 429        poll_wait(file, &dev->write_wait, wait);
 430
 431        if (dev->ring_head != dev->ring_tail)
 432                mask |= EPOLLIN | EPOLLRDNORM;
 433        if (!dev->interrupt_out_busy)
 434                mask |= EPOLLOUT | EPOLLWRNORM;
 435
 436        return mask;
 437}
 438
 439/**
 440 *      ld_usb_read
 441 */
 442static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
 443                           loff_t *ppos)
 444{
 445        struct ld_usb *dev;
 446        size_t *actual_buffer;
 447        size_t bytes_to_read;
 448        int retval = 0;
 449        int rv;
 450
 451        dev = file->private_data;
 452
 453        /* verify that we actually have some data to read */
 454        if (count == 0)
 455                goto exit;
 456
 457        /* lock this object */
 458        if (mutex_lock_interruptible(&dev->mutex)) {
 459                retval = -ERESTARTSYS;
 460                goto exit;
 461        }
 462
 463        /* verify that the device wasn't unplugged */
 464        if (dev->intf == NULL) {
 465                retval = -ENODEV;
 466                printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
 467                goto unlock_exit;
 468        }
 469
 470        /* wait for data */
 471        spin_lock_irq(&dev->rbsl);
 472        if (dev->ring_head == dev->ring_tail) {
 473                dev->interrupt_in_done = 0;
 474                spin_unlock_irq(&dev->rbsl);
 475                if (file->f_flags & O_NONBLOCK) {
 476                        retval = -EAGAIN;
 477                        goto unlock_exit;
 478                }
 479                retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
 480                if (retval < 0)
 481                        goto unlock_exit;
 482        } else {
 483                spin_unlock_irq(&dev->rbsl);
 484        }
 485
 486        /* actual_buffer contains actual_length + interrupt_in_buffer */
 487        actual_buffer = (size_t *)(dev->ring_buffer + dev->ring_tail * (sizeof(size_t)+dev->interrupt_in_endpoint_size));
 488        bytes_to_read = min(count, *actual_buffer);
 489        if (bytes_to_read < *actual_buffer)
 490                dev_warn(&dev->intf->dev, "Read buffer overflow, %zd 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        dev->ring_tail = (dev->ring_tail+1) % ring_buffer_size;
 499
 500        retval = bytes_to_read;
 501
 502        spin_lock_irq(&dev->rbsl);
 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->intf == NULL) {
 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, %zd bytes dropped\n", count-bytes_to_write);
 566        dev_dbg(&dev->intf->dev, "%s: count = %zd, bytes_to_write = %zd\n",
 567                __func__, count, bytes_to_write);
 568
 569        if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 570                retval = -EFAULT;
 571                goto unlock_exit;
 572        }
 573
 574        if (dev->interrupt_out_endpoint == NULL) {
 575                /* try HID_REQ_SET_REPORT=9 on control_endpoint instead of interrupt_out_endpoint */
 576                retval = usb_control_msg(interface_to_usbdev(dev->intf),
 577                                         usb_sndctrlpipe(interface_to_usbdev(dev->intf), 0),
 578                                         9,
 579                                         USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
 580                                         1 << 8, 0,
 581                                         dev->interrupt_out_buffer,
 582                                         bytes_to_write,
 583                                         USB_CTRL_SET_TIMEOUT * HZ);
 584                if (retval < 0)
 585                        dev_err(&dev->intf->dev,
 586                                "Couldn't submit HID_REQ_SET_REPORT %d\n",
 587                                retval);
 588                goto unlock_exit;
 589        }
 590
 591        /* send off the urb */
 592        usb_fill_int_urb(dev->interrupt_out_urb,
 593                         interface_to_usbdev(dev->intf),
 594                         usb_sndintpipe(interface_to_usbdev(dev->intf),
 595                                        dev->interrupt_out_endpoint->bEndpointAddress),
 596                         dev->interrupt_out_buffer,
 597                         bytes_to_write,
 598                         ld_usb_interrupt_out_callback,
 599                         dev,
 600                         dev->interrupt_out_interval);
 601
 602        dev->interrupt_out_busy = 1;
 603        wmb();
 604
 605        retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 606        if (retval) {
 607                dev->interrupt_out_busy = 0;
 608                dev_err(&dev->intf->dev,
 609                        "Couldn't submit interrupt_out_urb %d\n", retval);
 610                goto unlock_exit;
 611        }
 612        retval = bytes_to_write;
 613
 614unlock_exit:
 615        /* unlock the device */
 616        mutex_unlock(&dev->mutex);
 617
 618exit:
 619        return retval;
 620}
 621
 622/* file operations needed when we register this driver */
 623static const struct file_operations ld_usb_fops = {
 624        .owner =        THIS_MODULE,
 625        .read  =        ld_usb_read,
 626        .write =        ld_usb_write,
 627        .open =         ld_usb_open,
 628        .release =      ld_usb_release,
 629        .poll =         ld_usb_poll,
 630        .llseek =       no_llseek,
 631};
 632
 633/*
 634 * usb class driver info in order to get a minor number from the usb core,
 635 * and to have the device registered with the driver core
 636 */
 637static struct usb_class_driver ld_usb_class = {
 638        .name =         "ldusb%d",
 639        .fops =         &ld_usb_fops,
 640        .minor_base =   USB_LD_MINOR_BASE,
 641};
 642
 643/**
 644 *      ld_usb_probe
 645 *
 646 *      Called by the usb core when a new device is connected that it thinks
 647 *      this driver might be interested in.
 648 */
 649static int ld_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
 650{
 651        struct usb_device *udev = interface_to_usbdev(intf);
 652        struct ld_usb *dev = NULL;
 653        struct usb_host_interface *iface_desc;
 654        char *buffer;
 655        int retval = -ENOMEM;
 656        int res;
 657
 658        /* allocate memory for our device state and initialize it */
 659
 660        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 661        if (!dev)
 662                goto exit;
 663        mutex_init(&dev->mutex);
 664        spin_lock_init(&dev->rbsl);
 665        dev->intf = intf;
 666        init_waitqueue_head(&dev->read_wait);
 667        init_waitqueue_head(&dev->write_wait);
 668
 669        /* workaround for early firmware versions on fast computers */
 670        if ((le16_to_cpu(udev->descriptor.idVendor) == USB_VENDOR_ID_LD) &&
 671            ((le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_CASSY) ||
 672             (le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_COM3LAB)) &&
 673            (le16_to_cpu(udev->descriptor.bcdDevice) <= 0x103)) {
 674                buffer = kmalloc(256, GFP_KERNEL);
 675                if (!buffer)
 676                        goto error;
 677                /* usb_string makes SETUP+STALL to leave always ControlReadLoop */
 678                usb_string(udev, 255, buffer, 256);
 679                kfree(buffer);
 680        }
 681
 682        iface_desc = intf->cur_altsetting;
 683
 684        res = usb_find_last_int_in_endpoint(iface_desc,
 685                        &dev->interrupt_in_endpoint);
 686        if (res) {
 687                dev_err(&intf->dev, "Interrupt in endpoint not found\n");
 688                retval = res;
 689                goto error;
 690        }
 691
 692        res = usb_find_last_int_out_endpoint(iface_desc,
 693                        &dev->interrupt_out_endpoint);
 694        if (res)
 695                dev_warn(&intf->dev, "Interrupt out endpoint not found (using control endpoint instead)\n");
 696
 697        dev->interrupt_in_endpoint_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
 698        dev->ring_buffer = kmalloc(ring_buffer_size*(sizeof(size_t)+dev->interrupt_in_endpoint_size), GFP_KERNEL);
 699        if (!dev->ring_buffer)
 700                goto error;
 701        dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 702        if (!dev->interrupt_in_buffer)
 703                goto error;
 704        dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 705        if (!dev->interrupt_in_urb)
 706                goto error;
 707        dev->interrupt_out_endpoint_size = dev->interrupt_out_endpoint ? usb_endpoint_maxp(dev->interrupt_out_endpoint) :
 708                                                                         udev->descriptor.bMaxPacketSize0;
 709        dev->interrupt_out_buffer = kmalloc(write_buffer_size*dev->interrupt_out_endpoint_size, GFP_KERNEL);
 710        if (!dev->interrupt_out_buffer)
 711                goto error;
 712        dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 713        if (!dev->interrupt_out_urb)
 714                goto error;
 715        dev->interrupt_in_interval = min_interrupt_in_interval > dev->interrupt_in_endpoint->bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 716        if (dev->interrupt_out_endpoint)
 717                dev->interrupt_out_interval = min_interrupt_out_interval > dev->interrupt_out_endpoint->bInterval ? min_interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 718
 719        /* we can register the device now, as it is ready */
 720        usb_set_intfdata(intf, dev);
 721
 722        retval = usb_register_dev(intf, &ld_usb_class);
 723        if (retval) {
 724                /* something prevented us from registering this driver */
 725                dev_err(&intf->dev, "Not able to get a minor for this device.\n");
 726                usb_set_intfdata(intf, NULL);
 727                goto error;
 728        }
 729
 730        /* let the user know what node this device is now attached to */
 731        dev_info(&intf->dev, "LD USB Device #%d now attached to major %d minor %d\n",
 732                (intf->minor - USB_LD_MINOR_BASE), USB_MAJOR, intf->minor);
 733
 734exit:
 735        return retval;
 736
 737error:
 738        ld_usb_delete(dev);
 739
 740        return retval;
 741}
 742
 743/**
 744 *      ld_usb_disconnect
 745 *
 746 *      Called by the usb core when the device is removed from the system.
 747 */
 748static void ld_usb_disconnect(struct usb_interface *intf)
 749{
 750        struct ld_usb *dev;
 751        int minor;
 752
 753        dev = usb_get_intfdata(intf);
 754        usb_set_intfdata(intf, NULL);
 755
 756        minor = intf->minor;
 757
 758        /* give back our minor */
 759        usb_deregister_dev(intf, &ld_usb_class);
 760
 761        mutex_lock(&dev->mutex);
 762
 763        /* if the device is not opened, then we clean up right now */
 764        if (!dev->open_count) {
 765                mutex_unlock(&dev->mutex);
 766                ld_usb_delete(dev);
 767        } else {
 768                dev->intf = NULL;
 769                /* wake up pollers */
 770                wake_up_interruptible_all(&dev->read_wait);
 771                wake_up_interruptible_all(&dev->write_wait);
 772                mutex_unlock(&dev->mutex);
 773        }
 774
 775        dev_info(&intf->dev, "LD USB Device #%d now disconnected\n",
 776                 (minor - USB_LD_MINOR_BASE));
 777}
 778
 779/* usb specific object needed to register this driver with the usb subsystem */
 780static struct usb_driver ld_usb_driver = {
 781        .name =         "ldusb",
 782        .probe =        ld_usb_probe,
 783        .disconnect =   ld_usb_disconnect,
 784        .id_table =     ld_usb_table,
 785};
 786
 787module_usb_driver(ld_usb_driver);
 788
 789