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 */
  78 static 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 };
 116 MODULE_DEVICE_TABLE(usb, ld_usb_table);
 117 MODULE_AUTHOR("Michael Hund <mhund@ld-didactic.de>");
 118 MODULE_DESCRIPTION("LD USB Driver");
 119 MODULE_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  */
 124 static int ring_buffer_size = 128;
 125 module_param(ring_buffer_size, int, 0000);
 126 MODULE_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  */
 130 static int write_buffer_size = 10;
 131 module_param(write_buffer_size, int, 0000);
 132 MODULE_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  */
 143 static int min_interrupt_in_interval = 2;
 144 module_param(min_interrupt_in_interval, int, 0000);
 145 MODULE_PARM_DESC(min_interrupt_in_interval, "Minimum interrupt in interval in ms");
 146
 147 static int min_interrupt_out_interval = 2;
 148 module_param(min_interrupt_out_interval, int, 0000);
 149 MODULE_PARM_DESC(min_interrupt_out_interval, "Minimum interrupt out interval in ms");
 150
 151 /* Structure to hold all of our device specific stuff */
 152 struct 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
 184 static struct usb_driver ld_usb_driver;
 185
 186 /*
 187  *      ld_usb_abort_transfers
 188  *      aborts transfers and frees associated data structures
 189  */
 190 static 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  */
 204 static 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  */
 218 static 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
 260 resubmit:
 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);
 271 exit:
 272         dev->interrupt_in_done = 1;
 273         wake_up_interruptible(&dev->read_wait);
 274 }
 275
 276 /*
 277  *      ld_usb_interrupt_out_callback
 278  */
 279 static 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  */
 299 static 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
 361 unlock_exit:
 362         mutex_unlock(&dev->mutex);
 363
 364         return retval;
 365 }
 366
 367 /*
 368  *      ld_usb_release
 369  */
 370 static 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
 402 unlock_exit:
 403         mutex_unlock(&dev->mutex);
 404
 405 exit:
 406         return retval;
 407 }
 408
 409 /*
 410  *      ld_usb_poll
 411  */
 412 static __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  */
 436 static 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
 512 unlock_exit:
 513         /* unlock the device */
 514         mutex_unlock(&dev->mutex);
 515
 516 exit:
 517         return retval;
 518 }
 519
 520 /*
 521  *      ld_usb_write
 522  */
 523 static 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
 614 unlock_exit:
 615         /* unlock the device */
 616         mutex_unlock(&dev->mutex);
 617
 618 exit:
 619         return retval;
 620 }
 621
 622 /* file operations needed when we register this driver */
 623 static 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  */
 637 static 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  */
 649 static 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 = max_t(int, min_interrupt_in_interval,
 720                                            dev->interrupt_in_endpoint->bInterval);
 721         if (dev->interrupt_out_endpoint)
 722                 dev->interrupt_out_interval = max_t(int, min_interrupt_out_interval,
 723                                                     dev->interrupt_out_endpoint->bInterval);
 724
 725         /* we can register the device now, as it is ready */
 726         usb_set_intfdata(intf, dev);
 727
 728         retval = usb_register_dev(intf, &ld_usb_class);
 729         if (retval) {
 730                 /* something prevented us from registering this driver */
 731                 dev_err(&intf->dev, "Not able to get a minor for this device.\n");
 732                 usb_set_intfdata(intf, NULL);
 733                 goto error;
 734         }
 735
 736         /* let the user know what node this device is now attached to */
 737         dev_info(&intf->dev, "LD USB Device #%d now attached to major %d minor %d\n",
 738                 (intf->minor - USB_LD_MINOR_BASE), USB_MAJOR, intf->minor);
 739
 740 exit:
 741         return retval;
 742
 743 error:
 744         ld_usb_delete(dev);
 745
 746         return retval;
 747 }
 748
 749 /*
 750  *      ld_usb_disconnect
 751  *
 752  *      Called by the usb core when the device is removed from the system.
 753  */
 754 static void ld_usb_disconnect(struct usb_interface *intf)
 755 {
 756         struct ld_usb *dev;
 757         int minor;
 758
 759         dev = usb_get_intfdata(intf);
 760         usb_set_intfdata(intf, NULL);
 761
 762         minor = intf->minor;
 763
 764         /* give back our minor */
 765         usb_deregister_dev(intf, &ld_usb_class);
 766
 767         usb_poison_urb(dev->interrupt_in_urb);
 768         usb_poison_urb(dev->interrupt_out_urb);
 769
 770         mutex_lock(&dev->mutex);
 771
 772         /* if the device is not opened, then we clean up right now */
 773         if (!dev->open_count) {
 774                 mutex_unlock(&dev->mutex);
 775                 ld_usb_delete(dev);
 776         } else {
 777                 dev->disconnected = 1;
 778                 /* wake up pollers */
 779                 wake_up_interruptible_all(&dev->read_wait);
 780                 wake_up_interruptible_all(&dev->write_wait);
 781                 mutex_unlock(&dev->mutex);
 782         }
 783
 784         dev_info(&intf->dev, "LD USB Device #%d now disconnected\n",
 785                  (minor - USB_LD_MINOR_BASE));
 786 }
 787
 788 /* usb specific object needed to register this driver with the usb subsystem */
 789 static struct usb_driver ld_usb_driver = {
 790         .name =         "ldusb",
 791         .probe =        ld_usb_probe,
 792         .disconnect =   ld_usb_disconnect,
 793         .id_table =     ld_usb_table,
 794 };
 795
 796 module_usb_driver(ld_usb_driver);
 797