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