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");
 120
 121/* All interrupt in transfers are collected in a ring buffer to
 122 * avoid racing conditions and get better performance of the driver.
 123 */
 124static int ring_buffer_size = 128;
 125module_param(ring_buffer_size, int, 0000);
 126MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size in reports");
 127
 128/* The write_buffer can contain more than one interrupt out transfer.
 129 */
 130static int write_buffer_size = 10;
 131module_param(write_buffer_size, int, 0000);
 132MODULE_PARM_DESC(write_buffer_size, "Write buffer size in reports");
 133
 134/* As of kernel version 2.6.4 ehci-hcd uses an
 135 * "only one interrupt transfer per frame" shortcut
 136 * to simplify the scheduling of periodic transfers.
 137 * This conflicts with our standard 1ms intervals for in and out URBs.
 138 * We use default intervals of 2ms for in and 2ms for out transfers,
 139 * which should be fast enough.
 140 * Increase the interval to allow more devices that do interrupt transfers,
 141 * or set to 1 to use the standard interval from the endpoint descriptors.
 142 */
 143static int min_interrupt_in_interval = 2;
 144module_param(min_interrupt_in_interval, int, 0000);
 145MODULE_PARM_DESC(min_interrupt_in_interval, "Minimum interrupt in interval in ms");
 146
 147static int min_interrupt_out_interval = 2;
 148module_param(min_interrupt_out_interval, int, 0000);
 149MODULE_PARM_DESC(min_interrupt_out_interval, "Minimum interrupt out interval in ms");
 150
 151/* Structure to hold all of our device specific stuff */
 152struct ld_usb {
 153        struct mutex            mutex;          /* locks this structure */
 154        struct usb_interface    *intf;          /* save off the usb interface pointer */
 155        unsigned long           disconnected:1;
 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                usb_kill_urb(dev->interrupt_in_urb);
 196        }
 197        if (dev->interrupt_out_busy)
 198                usb_kill_urb(dev->interrupt_out_urb);
 199}
 200
 201/*
 202 *      ld_usb_delete
 203 */
 204static void ld_usb_delete(struct ld_usb *dev)
 205{
 206        /* free data structures */
 207        usb_free_urb(dev->interrupt_in_urb);
 208        usb_free_urb(dev->interrupt_out_urb);
 209        kfree(dev->ring_buffer);
 210        kfree(dev->interrupt_in_buffer);
 211        kfree(dev->interrupt_out_buffer);
 212        kfree(dev);
 213}
 214
 215/*
 216 *      ld_usb_interrupt_in_callback
 217 */
 218static void ld_usb_interrupt_in_callback(struct urb *urb)
 219{
 220        struct ld_usb *dev = urb->context;
 221        size_t *actual_buffer;
 222        unsigned int next_ring_head;
 223        int status = urb->status;
 224        unsigned long flags;
 225        int retval;
 226
 227        if (status) {
 228                if (status == -ENOENT ||
 229                    status == -ECONNRESET ||
 230                    status == -ESHUTDOWN) {
 231                        goto exit;
 232                } else {
 233                        dev_dbg(&dev->intf->dev,
 234                                "%s: nonzero status received: %d\n", __func__,
 235                                status);
 236                        spin_lock_irqsave(&dev->rbsl, flags);
 237                        goto resubmit; /* maybe we can recover */
 238                }
 239        }
 240
 241        spin_lock_irqsave(&dev->rbsl, flags);
 242        if (urb->actual_length > 0) {
 243                next_ring_head = (dev->ring_head+1) % ring_buffer_size;
 244                if (next_ring_head != dev->ring_tail) {
 245                        actual_buffer = (size_t *)(dev->ring_buffer + dev->ring_head * (sizeof(size_t)+dev->interrupt_in_endpoint_size));
 246                        /* actual_buffer gets urb->actual_length + interrupt_in_buffer */
 247                        *actual_buffer = urb->actual_length;
 248                        memcpy(actual_buffer+1, dev->interrupt_in_buffer, urb->actual_length);
 249                        dev->ring_head = next_ring_head;
 250                        dev_dbg(&dev->intf->dev, "%s: received %d bytes\n",
 251                                __func__, urb->actual_length);
 252                } else {
 253                        dev_warn(&dev->intf->dev,
 254                                 "Ring buffer overflow, %d bytes dropped\n",
 255                                 urb->actual_length);
 256                        dev->buffer_overflow = 1;
 257                }
 258        }
 259
 260resubmit:
 261        /* resubmit if we're still running */
 262        if (dev->interrupt_in_running && !dev->buffer_overflow) {
 263                retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
 264                if (retval) {
 265                        dev_err(&dev->intf->dev,
 266                                "usb_submit_urb failed (%d)\n", retval);
 267                        dev->buffer_overflow = 1;
 268                }
 269        }
 270        spin_unlock_irqrestore(&dev->rbsl, flags);
 271exit:
 272        dev->interrupt_in_done = 1;
 273        wake_up_interruptible(&dev->read_wait);
 274}
 275
 276/*
 277 *      ld_usb_interrupt_out_callback
 278 */
 279static void ld_usb_interrupt_out_callback(struct urb *urb)
 280{
 281        struct ld_usb *dev = urb->context;
 282        int status = urb->status;
 283
 284        /* sync/async unlink faults aren't errors */
 285        if (status && !(status == -ENOENT ||
 286                        status == -ECONNRESET ||
 287                        status == -ESHUTDOWN))
 288                dev_dbg(&dev->intf->dev,
 289                        "%s - nonzero write interrupt status received: %d\n",
 290                        __func__, status);
 291
 292        dev->interrupt_out_busy = 0;
 293        wake_up_interruptible(&dev->write_wait);
 294}
 295
 296/*
 297 *      ld_usb_open
 298 */
 299static int ld_usb_open(struct inode *inode, struct file *file)
 300{
 301        struct ld_usb *dev;
 302        int subminor;
 303        int retval;
 304        struct usb_interface *interface;
 305
 306        stream_open(inode, file);
 307        subminor = iminor(inode);
 308
 309        interface = usb_find_interface(&ld_usb_driver, subminor);
 310
 311        if (!interface) {
 312                printk(KERN_ERR "%s - error, can't find device for minor %d\n",
 313                       __func__, subminor);
 314                return -ENODEV;
 315        }
 316
 317        dev = usb_get_intfdata(interface);
 318
 319        if (!dev)
 320                return -ENODEV;
 321
 322        /* lock this device */
 323        if (mutex_lock_interruptible(&dev->mutex))
 324                return -ERESTARTSYS;
 325
 326        /* allow opening only once */
 327        if (dev->open_count) {
 328                retval = -EBUSY;
 329                goto unlock_exit;
 330        }
 331        dev->open_count = 1;
 332
 333        /* initialize in direction */
 334        dev->ring_head = 0;
 335        dev->ring_tail = 0;
 336        dev->buffer_overflow = 0;
 337        usb_fill_int_urb(dev->interrupt_in_urb,
 338                         interface_to_usbdev(interface),
 339                         usb_rcvintpipe(interface_to_usbdev(interface),
 340                                        dev->interrupt_in_endpoint->bEndpointAddress),
 341                         dev->interrupt_in_buffer,
 342                         dev->interrupt_in_endpoint_size,
 343                         ld_usb_interrupt_in_callback,
 344                         dev,
 345                         dev->interrupt_in_interval);
 346
 347        dev->interrupt_in_running = 1;
 348        dev->interrupt_in_done = 0;
 349
 350        retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 351        if (retval) {
 352                dev_err(&interface->dev, "Couldn't submit interrupt_in_urb %d\n", retval);
 353                dev->interrupt_in_running = 0;
 354                dev->open_count = 0;
 355                goto unlock_exit;
 356        }
 357
 358        /* save device in the file's private structure */
 359        file->private_data = dev;
 360
 361unlock_exit:
 362        mutex_unlock(&dev->mutex);
 363
 364        return retval;
 365}
 366
 367/*
 368 *      ld_usb_release
 369 */
 370static int ld_usb_release(struct inode *inode, struct file *file)
 371{
 372        struct ld_usb *dev;
 373        int retval = 0;
 374
 375        dev = file->private_data;
 376
 377        if (dev == NULL) {
 378                retval = -ENODEV;
 379                goto exit;
 380        }
 381
 382        mutex_lock(&dev->mutex);
 383
 384        if (dev->open_count != 1) {
 385                retval = -ENODEV;
 386                goto unlock_exit;
 387        }
 388        if (dev->disconnected) {
 389                /* the device was unplugged before the file was released */
 390                mutex_unlock(&dev->mutex);
 391                /* unlock here as ld_usb_delete frees dev */
 392                ld_usb_delete(dev);
 393                goto exit;
 394        }
 395
 396        /* wait until write transfer is finished */
 397        if (dev->interrupt_out_busy)
 398                wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 399        ld_usb_abort_transfers(dev);
 400        dev->open_count = 0;
 401
 402unlock_exit:
 403        mutex_unlock(&dev->mutex);
 404
 405exit:
 406        return retval;
 407}
 408
 409/*
 410 *      ld_usb_poll
 411 */
 412static __poll_t ld_usb_poll(struct file *file, poll_table *wait)
 413{
 414        struct ld_usb *dev;
 415        __poll_t mask = 0;
 416
 417        dev = file->private_data;
 418
 419        if (dev->disconnected)
 420                return EPOLLERR | EPOLLHUP;
 421
 422        poll_wait(file, &dev->read_wait, wait);
 423        poll_wait(file, &dev->write_wait, wait);
 424
 425        if (dev->ring_head != dev->ring_tail)
 426                mask |= EPOLLIN | EPOLLRDNORM;
 427        if (!dev->interrupt_out_busy)
 428                mask |= EPOLLOUT | EPOLLWRNORM;
 429
 430        return mask;
 431}
 432
 433/*
 434 *      ld_usb_read
 435 */
 436static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
 437                           loff_t *ppos)
 438{
 439        struct ld_usb *dev;
 440        size_t *actual_buffer;
 441        size_t bytes_to_read;
 442        int retval = 0;
 443        int rv;
 444
 445        dev = file->private_data;
 446
 447        /* verify that we actually have some data to read */
 448        if (count == 0)
 449                goto exit;
 450
 451        /* lock this object */
 452        if (mutex_lock_interruptible(&dev->mutex)) {
 453                retval = -ERESTARTSYS;
 454                goto exit;
 455        }
 456
 457        /* verify that the device wasn't unplugged */
 458        if (dev->disconnected) {
 459                retval = -ENODEV;
 460                printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
 461                goto unlock_exit;
 462        }
 463
 464        /* wait for data */
 465        spin_lock_irq(&dev->rbsl);
 466        while (dev->ring_head == dev->ring_tail) {
 467                dev->interrupt_in_done = 0;
 468                spin_unlock_irq(&dev->rbsl);
 469                if (file->f_flags & O_NONBLOCK) {
 470                        retval = -EAGAIN;
 471                        goto unlock_exit;
 472                }
 473                retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
 474                if (retval < 0)
 475                        goto unlock_exit;
 476
 477                spin_lock_irq(&dev->rbsl);
 478        }
 479        spin_unlock_irq(&dev->rbsl);
 480
 481        /* actual_buffer contains actual_length + interrupt_in_buffer */
 482        actual_buffer = (size_t *)(dev->ring_buffer + dev->ring_tail * (sizeof(size_t)+dev->interrupt_in_endpoint_size));
 483        if (*actual_buffer > dev->interrupt_in_endpoint_size) {
 484                retval = -EIO;
 485                goto unlock_exit;
 486        }
 487        bytes_to_read = min(count, *actual_buffer);
 488        if (bytes_to_read < *actual_buffer)
 489                dev_warn(&dev->intf->dev, "Read buffer overflow, %zu bytes dropped\n",
 490                         *actual_buffer-bytes_to_read);
 491
 492        /* copy one interrupt_in_buffer from ring_buffer into userspace */
 493        if (copy_to_user(buffer, actual_buffer+1, bytes_to_read)) {
 494                retval = -EFAULT;
 495                goto unlock_exit;
 496        }
 497        retval = bytes_to_read;
 498
 499        spin_lock_irq(&dev->rbsl);
 500        dev->ring_tail = (dev->ring_tail + 1) % ring_buffer_size;
 501
 502        if (dev->buffer_overflow) {
 503                dev->buffer_overflow = 0;
 504                spin_unlock_irq(&dev->rbsl);
 505                rv = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 506                if (rv < 0)
 507                        dev->buffer_overflow = 1;
 508        } else {
 509                spin_unlock_irq(&dev->rbsl);
 510        }
 511
 512unlock_exit:
 513        /* unlock the device */
 514        mutex_unlock(&dev->mutex);
 515
 516exit:
 517        return retval;
 518}
 519
 520/*
 521 *      ld_usb_write
 522 */
 523static ssize_t ld_usb_write(struct file *file, const char __user *buffer,
 524                            size_t count, loff_t *ppos)
 525{
 526        struct ld_usb *dev;
 527        size_t bytes_to_write;
 528        int retval = 0;
 529
 530        dev = file->private_data;
 531
 532        /* verify that we actually have some data to write */
 533        if (count == 0)
 534                goto exit;
 535
 536        /* lock this object */
 537        if (mutex_lock_interruptible(&dev->mutex)) {
 538                retval = -ERESTARTSYS;
 539                goto exit;
 540        }
 541
 542        /* verify that the device wasn't unplugged */
 543        if (dev->disconnected) {
 544                retval = -ENODEV;
 545                printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
 546                goto unlock_exit;
 547        }
 548
 549        /* wait until previous transfer is finished */
 550        if (dev->interrupt_out_busy) {
 551                if (file->f_flags & O_NONBLOCK) {
 552                        retval = -EAGAIN;
 553                        goto unlock_exit;
 554                }
 555                retval = wait_event_interruptible(dev->write_wait, !dev->interrupt_out_busy);
 556                if (retval < 0) {
 557                        goto unlock_exit;
 558                }
 559        }
 560
 561        /* write the data into interrupt_out_buffer from userspace */
 562        bytes_to_write = min(count, write_buffer_size*dev->interrupt_out_endpoint_size);
 563        if (bytes_to_write < count)
 564                dev_warn(&dev->intf->dev, "Write buffer overflow, %zu bytes dropped\n",
 565                        count - bytes_to_write);
 566        dev_dbg(&dev->intf->dev, "%s: count = %zu, bytes_to_write = %zu\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);
 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 = kcalloc(ring_buffer_size,
 699                        sizeof(size_t) + dev->interrupt_in_endpoint_size,
 700                        GFP_KERNEL);
 701        if (!dev->ring_buffer)
 702                goto error;
 703        dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 704        if (!dev->interrupt_in_buffer)
 705                goto error;
 706        dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 707        if (!dev->interrupt_in_urb)
 708                goto error;
 709        dev->interrupt_out_endpoint_size = dev->interrupt_out_endpoint ? usb_endpoint_maxp(dev->interrupt_out_endpoint) :
 710                                                                         udev->descriptor.bMaxPacketSize0;
 711        dev->interrupt_out_buffer =
 712                kmalloc_array(write_buffer_size,
 713                              dev->interrupt_out_endpoint_size, GFP_KERNEL);
 714        if (!dev->interrupt_out_buffer)
 715                goto error;
 716        dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 717        if (!dev->interrupt_out_urb)
 718                goto error;
 719        dev->interrupt_in_interval = min_interrupt_in_interval > dev->interrupt_in_endpoint->bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 720        if (dev->interrupt_out_endpoint)
 721                dev->interrupt_out_interval = min_interrupt_out_interval > dev->interrupt_out_endpoint->bInterval ? min_interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 722
 723        /* we can register the device now, as it is ready */
 724        usb_set_intfdata(intf, dev);
 725
 726        retval = usb_register_dev(intf, &ld_usb_class);
 727        if (retval) {
 728                /* something prevented us from registering this driver */
 729                dev_err(&intf->dev, "Not able to get a minor for this device.\n");
 730                usb_set_intfdata(intf, NULL);
 731                goto error;
 732        }
 733
 734        /* let the user know what node this device is now attached to */
 735        dev_info(&intf->dev, "LD USB Device #%d now attached to major %d minor %d\n",
 736                (intf->minor - USB_LD_MINOR_BASE), USB_MAJOR, intf->minor);
 737
 738exit:
 739        return retval;
 740
 741error:
 742        ld_usb_delete(dev);
 743
 744        return retval;
 745}
 746
 747/*
 748 *      ld_usb_disconnect
 749 *
 750 *      Called by the usb core when the device is removed from the system.
 751 */
 752static void ld_usb_disconnect(struct usb_interface *intf)
 753{
 754        struct ld_usb *dev;
 755        int minor;
 756
 757        dev = usb_get_intfdata(intf);
 758        usb_set_intfdata(intf, NULL);
 759
 760        minor = intf->minor;
 761
 762        /* give back our minor */
 763        usb_deregister_dev(intf, &ld_usb_class);
 764
 765        usb_poison_urb(dev->interrupt_in_urb);
 766        usb_poison_urb(dev->interrupt_out_urb);
 767
 768        mutex_lock(&dev->mutex);
 769
 770        /* if the device is not opened, then we clean up right now */
 771        if (!dev->open_count) {
 772                mutex_unlock(&dev->mutex);
 773                ld_usb_delete(dev);
 774        } else {
 775                dev->disconnected = 1;
 776                /* wake up pollers */
 777                wake_up_interruptible_all(&dev->read_wait);
 778                wake_up_interruptible_all(&dev->write_wait);
 779                mutex_unlock(&dev->mutex);
 780        }
 781
 782        dev_info(&intf->dev, "LD USB Device #%d now disconnected\n",
 783                 (minor - USB_LD_MINOR_BASE));
 784}
 785
 786/* usb specific object needed to register this driver with the usb subsystem */
 787static struct usb_driver ld_usb_driver = {
 788        .name =         "ldusb",
 789        .probe =        ld_usb_probe,
 790        .disconnect =   ld_usb_disconnect,
 791        .id_table =     ld_usb_table,
 792};
 793
 794module_usb_driver(ld_usb_driver);
 795
 796