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 MODULE_SUPPORTED_DEVICE("LD USB Devices");
 121
 122 /* All interrupt in transfers are collected in a ring buffer to
 123  * avoid racing conditions and get better performance of the driver.
 124  */
 125 static int ring_buffer_size = 128;
 126 module_param(ring_buffer_size, int, 0000);
 127 MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size in reports");
 128
 129 /* The write_buffer can contain more than one interrupt out transfer.
 130  */
 131 static int write_buffer_size = 10;
 132 module_param(write_buffer_size, int, 0000);
 133 MODULE_PARM_DESC(write_buffer_size, "Write buffer size in reports");
 134
 135 /* As of kernel version 2.6.4 ehci-hcd uses an
 136  * "only one interrupt transfer per frame" shortcut
 137  * to simplify the scheduling of periodic transfers.
 138  * This conflicts with our standard 1ms intervals for in and out URBs.
 139  * We use default intervals of 2ms for in and 2ms for out transfers,
 140  * which should be fast enough.
 141  * Increase the interval to allow more devices that do interrupt transfers,
 142  * or set to 1 to use the standard interval from the endpoint descriptors.
 143  */
 144 static int min_interrupt_in_interval = 2;
 145 module_param(min_interrupt_in_interval, int, 0000);
 146 MODULE_PARM_DESC(min_interrupt_in_interval, "Minimum interrupt in interval in ms");
 147
 148 static int min_interrupt_out_interval = 2;
 149 module_param(min_interrupt_out_interval, int, 0000);
 150 MODULE_PARM_DESC(min_interrupt_out_interval, "Minimum interrupt out interval in ms");
 151
 152 /* Structure to hold all of our device specific stuff */
 153 struct ld_usb {
 154         struct mutex            mutex;          /* locks this structure */
 155         struct usb_interface    *intf;          /* save off the usb interface pointer */
 156         unsigned long           disconnected:1;
 157
 158         int                     open_count;     /* number of times this port has been opened */
 159
 160         char                    *ring_buffer;
 161         unsigned int            ring_head;
 162         unsigned int            ring_tail;
 163
 164         wait_queue_head_t       read_wait;
 165         wait_queue_head_t       write_wait;
 166
 167         char                    *interrupt_in_buffer;
 168         struct usb_endpoint_descriptor *interrupt_in_endpoint;
 169         struct urb              *interrupt_in_urb;
 170         int                     interrupt_in_interval;
 171         size_t                  interrupt_in_endpoint_size;
 172         int                     interrupt_in_running;
 173         int                     interrupt_in_done;
 174         int                     buffer_overflow;
 175         spinlock_t              rbsl;
 176
 177         char                    *interrupt_out_buffer;
 178         struct usb_endpoint_descriptor *interrupt_out_endpoint;
 179         struct urb              *interrupt_out_urb;
 180         int                     interrupt_out_interval;
 181         size_t                  interrupt_out_endpoint_size;
 182         int                     interrupt_out_busy;
 183 };
 184
 185 static struct usb_driver ld_usb_driver;
 186
 187 /**
 188  *      ld_usb_abort_transfers
 189  *      aborts transfers and frees associated data structures
 190  */
 191 static void ld_usb_abort_transfers(struct ld_usb *dev)
 192 {
 193         /* shutdown transfer */
 194         if (dev->interrupt_in_running) {
 195                 dev->interrupt_in_running = 0;
 196                 usb_kill_urb(dev->interrupt_in_urb);
 197         }
 198         if (dev->interrupt_out_busy)
 199                 usb_kill_urb(dev->interrupt_out_urb);
 200 }
 201
 202 /**
 203  *      ld_usb_delete
 204  */
 205 static void ld_usb_delete(struct ld_usb *dev)
 206 {
 207         /* free data structures */
 208         usb_free_urb(dev->interrupt_in_urb);
 209         usb_free_urb(dev->interrupt_out_urb);
 210         kfree(dev->ring_buffer);
 211         kfree(dev->interrupt_in_buffer);
 212         kfree(dev->interrupt_out_buffer);
 213         kfree(dev);
 214 }
 215
 216 /**
 217  *      ld_usb_interrupt_in_callback
 218  */
 219 static void ld_usb_interrupt_in_callback(struct urb *urb)
 220 {
 221         struct ld_usb *dev = urb->context;
 222         size_t *actual_buffer;
 223         unsigned int next_ring_head;
 224         int status = urb->status;
 225         unsigned long flags;
 226         int retval;
 227
 228         if (status) {
 229                 if (status == -ENOENT ||
 230                     status == -ECONNRESET ||
 231                     status == -ESHUTDOWN) {
 232                         goto exit;
 233                 } else {
 234                         dev_dbg(&dev->intf->dev,
 235                                 "%s: nonzero status received: %d\n", __func__,
 236                                 status);
 237                         spin_lock_irqsave(&dev->rbsl, flags);
 238                         goto resubmit; /* maybe we can recover */
 239                 }
 240         }
 241
 242         spin_lock_irqsave(&dev->rbsl, flags);
 243         if (urb->actual_length > 0) {
 244                 next_ring_head = (dev->ring_head+1) % ring_buffer_size;
 245                 if (next_ring_head != dev->ring_tail) {
 246                         actual_buffer = (size_t *)(dev->ring_buffer + dev->ring_head * (sizeof(size_t)+dev->interrupt_in_endpoint_size));
 247                         /* actual_buffer gets urb->actual_length + interrupt_in_buffer */
 248                         *actual_buffer = urb->actual_length;
 249                         memcpy(actual_buffer+1, dev->interrupt_in_buffer, urb->actual_length);
 250                         dev->ring_head = next_ring_head;
 251                         dev_dbg(&dev->intf->dev, "%s: received %d bytes\n",
 252                                 __func__, urb->actual_length);
 253                 } else {
 254                         dev_warn(&dev->intf->dev,
 255                                  "Ring buffer overflow, %d bytes dropped\n",
 256                                  urb->actual_length);
 257                         dev->buffer_overflow = 1;
 258                 }
 259         }
 260
 261 resubmit:
 262         /* resubmit if we're still running */
 263         if (dev->interrupt_in_running && !dev->buffer_overflow) {
 264                 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
 265                 if (retval) {
 266                         dev_err(&dev->intf->dev,
 267                                 "usb_submit_urb failed (%d)\n", retval);
 268                         dev->buffer_overflow = 1;
 269                 }
 270         }
 271         spin_unlock_irqrestore(&dev->rbsl, flags);
 272 exit:
 273         dev->interrupt_in_done = 1;
 274         wake_up_interruptible(&dev->read_wait);
 275 }
 276
 277 /**
 278  *      ld_usb_interrupt_out_callback
 279  */
 280 static void ld_usb_interrupt_out_callback(struct urb *urb)
 281 {
 282         struct ld_usb *dev = urb->context;
 283         int status = urb->status;
 284
 285         /* sync/async unlink faults aren't errors */
 286         if (status && !(status == -ENOENT ||
 287                         status == -ECONNRESET ||
 288                         status == -ESHUTDOWN))
 289                 dev_dbg(&dev->intf->dev,
 290                         "%s - nonzero write interrupt status received: %d\n",
 291                         __func__, status);
 292
 293         dev->interrupt_out_busy = 0;
 294         wake_up_interruptible(&dev->write_wait);
 295 }
 296
 297 /**
 298  *      ld_usb_open
 299  */
 300 static int ld_usb_open(struct inode *inode, struct file *file)
 301 {
 302         struct ld_usb *dev;
 303         int subminor;
 304         int retval;
 305         struct usb_interface *interface;
 306
 307         stream_open(inode, file);
 308         subminor = iminor(inode);
 309
 310         interface = usb_find_interface(&ld_usb_driver, subminor);
 311
 312         if (!interface) {
 313                 printk(KERN_ERR "%s - error, can't find device for minor %d\n",
 314                        __func__, subminor);
 315                 return -ENODEV;
 316         }
 317
 318         dev = usb_get_intfdata(interface);
 319
 320         if (!dev)
 321                 return -ENODEV;
 322
 323         /* lock this device */
 324         if (mutex_lock_interruptible(&dev->mutex))
 325                 return -ERESTARTSYS;
 326
 327         /* allow opening only once */
 328         if (dev->open_count) {
 329                 retval = -EBUSY;
 330                 goto unlock_exit;
 331         }
 332         dev->open_count = 1;
 333
 334         /* initialize in direction */
 335         dev->ring_head = 0;
 336         dev->ring_tail = 0;
 337         dev->buffer_overflow = 0;
 338         usb_fill_int_urb(dev->interrupt_in_urb,
 339                          interface_to_usbdev(interface),
 340                          usb_rcvintpipe(interface_to_usbdev(interface),
 341                                         dev->interrupt_in_endpoint->bEndpointAddress),
 342                          dev->interrupt_in_buffer,
 343                          dev->interrupt_in_endpoint_size,
 344                          ld_usb_interrupt_in_callback,
 345                          dev,
 346                          dev->interrupt_in_interval);
 347
 348         dev->interrupt_in_running = 1;
 349         dev->interrupt_in_done = 0;
 350
 351         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 352         if (retval) {
 353                 dev_err(&interface->dev, "Couldn't submit interrupt_in_urb %d\n", retval);
 354                 dev->interrupt_in_running = 0;
 355                 dev->open_count = 0;
 356                 goto unlock_exit;
 357         }
 358
 359         /* save device in the file's private structure */
 360         file->private_data = dev;
 361
 362 unlock_exit:
 363         mutex_unlock(&dev->mutex);
 364
 365         return retval;
 366 }
 367
 368 /**
 369  *      ld_usb_release
 370  */
 371 static int ld_usb_release(struct inode *inode, struct file *file)
 372 {
 373         struct ld_usb *dev;
 374         int retval = 0;
 375
 376         dev = file->private_data;
 377
 378         if (dev == NULL) {
 379                 retval = -ENODEV;
 380                 goto exit;
 381         }
 382
 383         if (mutex_lock_interruptible(&dev->mutex)) {
 384                 retval = -ERESTARTSYS;
 385                 goto exit;
 386         }
 387
 388         if (dev->open_count != 1) {
 389                 retval = -ENODEV;
 390                 goto unlock_exit;
 391         }
 392         if (dev->disconnected) {
 393                 /* the device was unplugged before the file was released */
 394                 mutex_unlock(&dev->mutex);
 395                 /* unlock here as ld_usb_delete frees dev */
 396                 ld_usb_delete(dev);
 397                 goto exit;
 398         }
 399
 400         /* wait until write transfer is finished */
 401         if (dev->interrupt_out_busy)
 402                 wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 403         ld_usb_abort_transfers(dev);
 404         dev->open_count = 0;
 405
 406 unlock_exit:
 407         mutex_unlock(&dev->mutex);
 408
 409 exit:
 410         return retval;
 411 }
 412
 413 /**
 414  *      ld_usb_poll
 415  */
 416 static __poll_t ld_usb_poll(struct file *file, poll_table *wait)
 417 {
 418         struct ld_usb *dev;
 419         __poll_t mask = 0;
 420
 421         dev = file->private_data;
 422
 423         if (dev->disconnected)
 424                 return EPOLLERR | EPOLLHUP;
 425
 426         poll_wait(file, &dev->read_wait, wait);
 427         poll_wait(file, &dev->write_wait, wait);
 428
 429         if (dev->ring_head != dev->ring_tail)
 430                 mask |= EPOLLIN | EPOLLRDNORM;
 431         if (!dev->interrupt_out_busy)
 432                 mask |= EPOLLOUT | EPOLLWRNORM;
 433
 434         return mask;
 435 }
 436
 437 /**
 438  *      ld_usb_read
 439  */
 440 static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
 441                            loff_t *ppos)
 442 {
 443         struct ld_usb *dev;
 444         size_t *actual_buffer;
 445         size_t bytes_to_read;
 446         int retval = 0;
 447         int rv;
 448
 449         dev = file->private_data;
 450
 451         /* verify that we actually have some data to read */
 452         if (count == 0)
 453                 goto exit;
 454
 455         /* lock this object */
 456         if (mutex_lock_interruptible(&dev->mutex)) {
 457                 retval = -ERESTARTSYS;
 458                 goto exit;
 459         }
 460
 461         /* verify that the device wasn't unplugged */
 462         if (dev->disconnected) {
 463                 retval = -ENODEV;
 464                 printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
 465                 goto unlock_exit;
 466         }
 467
 468         /* wait for data */
 469         spin_lock_irq(&dev->rbsl);
 470         if (dev->ring_head == dev->ring_tail) {
 471                 dev->interrupt_in_done = 0;
 472                 spin_unlock_irq(&dev->rbsl);
 473                 if (file->f_flags & O_NONBLOCK) {
 474                         retval = -EAGAIN;
 475                         goto unlock_exit;
 476                 }
 477                 retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
 478                 if (retval < 0)
 479                         goto unlock_exit;
 480         } else {
 481                 spin_unlock_irq(&dev->rbsl);
 482         }
 483
 484         /* actual_buffer contains actual_length + interrupt_in_buffer */
 485         actual_buffer = (size_t *)(dev->ring_buffer + dev->ring_tail * (sizeof(size_t)+dev->interrupt_in_endpoint_size));
 486         bytes_to_read = min(count, *actual_buffer);
 487         if (bytes_to_read < *actual_buffer)
 488                 dev_warn(&dev->intf->dev, "Read buffer overflow, %zd bytes dropped\n",
 489                          *actual_buffer-bytes_to_read);
 490
 491         /* copy one interrupt_in_buffer from ring_buffer into userspace */
 492         if (copy_to_user(buffer, actual_buffer+1, bytes_to_read)) {
 493                 retval = -EFAULT;
 494                 goto unlock_exit;
 495         }
 496         dev->ring_tail = (dev->ring_tail+1) % ring_buffer_size;
 497
 498         retval = bytes_to_read;
 499
 500         spin_lock_irq(&dev->rbsl);
 501         if (dev->buffer_overflow) {
 502                 dev->buffer_overflow = 0;
 503                 spin_unlock_irq(&dev->rbsl);
 504                 rv = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 505                 if (rv < 0)
 506                         dev->buffer_overflow = 1;
 507         } else {
 508                 spin_unlock_irq(&dev->rbsl);
 509         }
 510
 511 unlock_exit:
 512         /* unlock the device */
 513         mutex_unlock(&dev->mutex);
 514
 515 exit:
 516         return retval;
 517 }
 518
 519 /**
 520  *      ld_usb_write
 521  */
 522 static ssize_t ld_usb_write(struct file *file, const char __user *buffer,
 523                             size_t count, loff_t *ppos)
 524 {
 525         struct ld_usb *dev;
 526         size_t bytes_to_write;
 527         int retval = 0;
 528
 529         dev = file->private_data;
 530
 531         /* verify that we actually have some data to write */
 532         if (count == 0)
 533                 goto exit;
 534
 535         /* lock this object */
 536         if (mutex_lock_interruptible(&dev->mutex)) {
 537                 retval = -ERESTARTSYS;
 538                 goto exit;
 539         }
 540
 541         /* verify that the device wasn't unplugged */
 542         if (dev->disconnected) {
 543                 retval = -ENODEV;
 544                 printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
 545                 goto unlock_exit;
 546         }
 547
 548         /* wait until previous transfer is finished */
 549         if (dev->interrupt_out_busy) {
 550                 if (file->f_flags & O_NONBLOCK) {
 551                         retval = -EAGAIN;
 552                         goto unlock_exit;
 553                 }
 554                 retval = wait_event_interruptible(dev->write_wait, !dev->interrupt_out_busy);
 555                 if (retval < 0) {
 556                         goto unlock_exit;
 557                 }
 558         }
 559
 560         /* write the data into interrupt_out_buffer from userspace */
 561         bytes_to_write = min(count, write_buffer_size*dev->interrupt_out_endpoint_size);
 562         if (bytes_to_write < count)
 563                 dev_warn(&dev->intf->dev, "Write buffer overflow, %zd bytes dropped\n", count-bytes_to_write);
 564         dev_dbg(&dev->intf->dev, "%s: count = %zd, bytes_to_write = %zd\n",
 565                 __func__, count, bytes_to_write);
 566
 567         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 568                 retval = -EFAULT;
 569                 goto unlock_exit;
 570         }
 571
 572         if (dev->interrupt_out_endpoint == NULL) {
 573                 /* try HID_REQ_SET_REPORT=9 on control_endpoint instead of interrupt_out_endpoint */
 574                 retval = usb_control_msg(interface_to_usbdev(dev->intf),
 575                                          usb_sndctrlpipe(interface_to_usbdev(dev->intf), 0),
 576                                          9,
 577                                          USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
 578                                          1 << 8, 0,
 579                                          dev->interrupt_out_buffer,
 580                                          bytes_to_write,
 581                                          USB_CTRL_SET_TIMEOUT * HZ);
 582                 if (retval < 0)
 583                         dev_err(&dev->intf->dev,
 584                                 "Couldn't submit HID_REQ_SET_REPORT %d\n",
 585                                 retval);
 586                 goto unlock_exit;
 587         }
 588
 589         /* send off the urb */
 590         usb_fill_int_urb(dev->interrupt_out_urb,
 591                          interface_to_usbdev(dev->intf),
 592                          usb_sndintpipe(interface_to_usbdev(dev->intf),
 593                                         dev->interrupt_out_endpoint->bEndpointAddress),
 594                          dev->interrupt_out_buffer,
 595                          bytes_to_write,
 596                          ld_usb_interrupt_out_callback,
 597                          dev,
 598                          dev->interrupt_out_interval);
 599
 600         dev->interrupt_out_busy = 1;
 601         wmb();
 602
 603         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 604         if (retval) {
 605                 dev->interrupt_out_busy = 0;
 606                 dev_err(&dev->intf->dev,
 607                         "Couldn't submit interrupt_out_urb %d\n", retval);
 608                 goto unlock_exit;
 609         }
 610         retval = bytes_to_write;
 611
 612 unlock_exit:
 613         /* unlock the device */
 614         mutex_unlock(&dev->mutex);
 615
 616 exit:
 617         return retval;
 618 }
 619
 620 /* file operations needed when we register this driver */
 621 static const struct file_operations ld_usb_fops = {
 622         .owner =        THIS_MODULE,
 623         .read  =        ld_usb_read,
 624         .write =        ld_usb_write,
 625         .open =         ld_usb_open,
 626         .release =      ld_usb_release,
 627         .poll =         ld_usb_poll,
 628         .llseek =       no_llseek,
 629 };
 630
 631 /*
 632  * usb class driver info in order to get a minor number from the usb core,
 633  * and to have the device registered with the driver core
 634  */
 635 static struct usb_class_driver ld_usb_class = {
 636         .name =         "ldusb%d",
 637         .fops =         &ld_usb_fops,
 638         .minor_base =   USB_LD_MINOR_BASE,
 639 };
 640
 641 /**
 642  *      ld_usb_probe
 643  *
 644  *      Called by the usb core when a new device is connected that it thinks
 645  *      this driver might be interested in.
 646  */
 647 static int ld_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
 648 {
 649         struct usb_device *udev = interface_to_usbdev(intf);
 650         struct ld_usb *dev = NULL;
 651         struct usb_host_interface *iface_desc;
 652         char *buffer;
 653         int retval = -ENOMEM;
 654         int res;
 655
 656         /* allocate memory for our device state and initialize it */
 657
 658         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 659         if (!dev)
 660                 goto exit;
 661         mutex_init(&dev->mutex);
 662         spin_lock_init(&dev->rbsl);
 663         dev->intf = intf;
 664         init_waitqueue_head(&dev->read_wait);
 665         init_waitqueue_head(&dev->write_wait);
 666
 667         /* workaround for early firmware versions on fast computers */
 668         if ((le16_to_cpu(udev->descriptor.idVendor) == USB_VENDOR_ID_LD) &&
 669             ((le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_CASSY) ||
 670              (le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_COM3LAB)) &&
 671             (le16_to_cpu(udev->descriptor.bcdDevice) <= 0x103)) {
 672                 buffer = kmalloc(256, GFP_KERNEL);
 673                 if (!buffer)
 674                         goto error;
 675                 /* usb_string makes SETUP+STALL to leave always ControlReadLoop */
 676                 usb_string(udev, 255, buffer, 256);
 677                 kfree(buffer);
 678         }
 679
 680         iface_desc = intf->cur_altsetting;
 681
 682         res = usb_find_last_int_in_endpoint(iface_desc,
 683                         &dev->interrupt_in_endpoint);
 684         if (res) {
 685                 dev_err(&intf->dev, "Interrupt in endpoint not found\n");
 686                 retval = res;
 687                 goto error;
 688         }
 689
 690         res = usb_find_last_int_out_endpoint(iface_desc,
 691                         &dev->interrupt_out_endpoint);
 692         if (res)
 693                 dev_warn(&intf->dev, "Interrupt out endpoint not found (using control endpoint instead)\n");
 694
 695         dev->interrupt_in_endpoint_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
 696         dev->ring_buffer =
 697                 kmalloc_array(ring_buffer_size,
 698                               sizeof(size_t) + dev->interrupt_in_endpoint_size,
 699                               GFP_KERNEL);
 700         if (!dev->ring_buffer)
 701                 goto error;
 702         dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 703         if (!dev->interrupt_in_buffer)
 704                 goto error;
 705         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 706         if (!dev->interrupt_in_urb)
 707                 goto error;
 708         dev->interrupt_out_endpoint_size = dev->interrupt_out_endpoint ? usb_endpoint_maxp(dev->interrupt_out_endpoint) :
 709                                                                          udev->descriptor.bMaxPacketSize0;
 710         dev->interrupt_out_buffer =
 711                 kmalloc_array(write_buffer_size,
 712                               dev->interrupt_out_endpoint_size, GFP_KERNEL);
 713         if (!dev->interrupt_out_buffer)
 714                 goto error;
 715         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 716         if (!dev->interrupt_out_urb)
 717                 goto error;
 718         dev->interrupt_in_interval = min_interrupt_in_interval > dev->interrupt_in_endpoint->bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 719         if (dev->interrupt_out_endpoint)
 720                 dev->interrupt_out_interval = min_interrupt_out_interval > dev->interrupt_out_endpoint->bInterval ? min_interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 721
 722         /* we can register the device now, as it is ready */
 723         usb_set_intfdata(intf, dev);
 724
 725         retval = usb_register_dev(intf, &ld_usb_class);
 726         if (retval) {
 727                 /* something prevented us from registering this driver */
 728                 dev_err(&intf->dev, "Not able to get a minor for this device.\n");
 729                 usb_set_intfdata(intf, NULL);
 730                 goto error;
 731         }
 732
 733         /* let the user know what node this device is now attached to */
 734         dev_info(&intf->dev, "LD USB Device #%d now attached to major %d minor %d\n",
 735                 (intf->minor - USB_LD_MINOR_BASE), USB_MAJOR, intf->minor);
 736
 737 exit:
 738         return retval;
 739
 740 error:
 741         ld_usb_delete(dev);
 742
 743         return retval;
 744 }
 745
 746 /**
 747  *      ld_usb_disconnect
 748  *
 749  *      Called by the usb core when the device is removed from the system.
 750  */
 751 static void ld_usb_disconnect(struct usb_interface *intf)
 752 {
 753         struct ld_usb *dev;
 754         int minor;
 755
 756         dev = usb_get_intfdata(intf);
 757         usb_set_intfdata(intf, NULL);
 758
 759         minor = intf->minor;
 760
 761         /* give back our minor */
 762         usb_deregister_dev(intf, &ld_usb_class);
 763
 764         usb_poison_urb(dev->interrupt_in_urb);
 765         usb_poison_urb(dev->interrupt_out_urb);
 766
 767         mutex_lock(&dev->mutex);
 768
 769         /* if the device is not opened, then we clean up right now */
 770         if (!dev->open_count) {
 771                 mutex_unlock(&dev->mutex);
 772                 ld_usb_delete(dev);
 773         } else {
 774                 dev->disconnected = 1;
 775                 /* wake up pollers */
 776                 wake_up_interruptible_all(&dev->read_wait);
 777                 wake_up_interruptible_all(&dev->write_wait);
 778                 mutex_unlock(&dev->mutex);
 779         }
 780
 781         dev_info(&intf->dev, "LD USB Device #%d now disconnected\n",
 782                  (minor - USB_LD_MINOR_BASE));
 783 }
 784
 785 /* usb specific object needed to register this driver with the usb subsystem */
 786 static struct usb_driver ld_usb_driver = {
 787         .name =         "ldusb",
 788         .probe =        ld_usb_probe,
 789         .disconnect =   ld_usb_disconnect,
 790         .id_table =     ld_usb_table,
 791 };
 792
 793 module_usb_driver(ld_usb_driver);
 794