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
 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                 if (dev->intf)
 196                         usb_kill_urb(dev->interrupt_in_urb);
 197         }
 198         if (dev->interrupt_out_busy)
 199                 if (dev->intf)
 200                         usb_kill_urb(dev->interrupt_out_urb);
 201 }
 202
 203 /**
 204  *      ld_usb_delete
 205  */
 206 static void ld_usb_delete(struct ld_usb *dev)
 207 {
 208         ld_usb_abort_transfers(dev);
 209
 210         /* free data structures */
 211         usb_free_urb(dev->interrupt_in_urb);
 212         usb_free_urb(dev->interrupt_out_urb);
 213         kfree(dev->ring_buffer);
 214         kfree(dev->interrupt_in_buffer);
 215         kfree(dev->interrupt_out_buffer);
 216         kfree(dev);
 217 }
 218
 219 /**
 220  *      ld_usb_interrupt_in_callback
 221  */
 222 static void ld_usb_interrupt_in_callback(struct urb *urb)
 223 {
 224         struct ld_usb *dev = urb->context;
 225         size_t *actual_buffer;
 226         unsigned int next_ring_head;
 227         int status = urb->status;
 228         unsigned long flags;
 229         int retval;
 230
 231         if (status) {
 232                 if (status == -ENOENT ||
 233                     status == -ECONNRESET ||
 234                     status == -ESHUTDOWN) {
 235                         goto exit;
 236                 } else {
 237                         dev_dbg(&dev->intf->dev,
 238                                 "%s: nonzero status received: %d\n", __func__,
 239                                 status);
 240                         spin_lock_irqsave(&dev->rbsl, flags);
 241                         goto resubmit; /* maybe we can recover */
 242                 }
 243         }
 244
 245         spin_lock_irqsave(&dev->rbsl, flags);
 246         if (urb->actual_length > 0) {
 247                 next_ring_head = (dev->ring_head+1) % ring_buffer_size;
 248                 if (next_ring_head != dev->ring_tail) {
 249                         actual_buffer = (size_t *)(dev->ring_buffer + dev->ring_head * (sizeof(size_t)+dev->interrupt_in_endpoint_size));
 250                         /* actual_buffer gets urb->actual_length + interrupt_in_buffer */
 251                         *actual_buffer = urb->actual_length;
 252                         memcpy(actual_buffer+1, dev->interrupt_in_buffer, urb->actual_length);
 253                         dev->ring_head = next_ring_head;
 254                         dev_dbg(&dev->intf->dev, "%s: received %d bytes\n",
 255                                 __func__, urb->actual_length);
 256                 } else {
 257                         dev_warn(&dev->intf->dev,
 258                                  "Ring buffer overflow, %d bytes dropped\n",
 259                                  urb->actual_length);
 260                         dev->buffer_overflow = 1;
 261                 }
 262         }
 263
 264 resubmit:
 265         /* resubmit if we're still running */
 266         if (dev->interrupt_in_running && !dev->buffer_overflow && dev->intf) {
 267                 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
 268                 if (retval) {
 269                         dev_err(&dev->intf->dev,
 270                                 "usb_submit_urb failed (%d)\n", retval);
 271                         dev->buffer_overflow = 1;
 272                 }
 273         }
 274         spin_unlock_irqrestore(&dev->rbsl, flags);
 275 exit:
 276         dev->interrupt_in_done = 1;
 277         wake_up_interruptible(&dev->read_wait);
 278 }
 279
 280 /**
 281  *      ld_usb_interrupt_out_callback
 282  */
 283 static void ld_usb_interrupt_out_callback(struct urb *urb)
 284 {
 285         struct ld_usb *dev = urb->context;
 286         int status = urb->status;
 287
 288         /* sync/async unlink faults aren't errors */
 289         if (status && !(status == -ENOENT ||
 290                         status == -ECONNRESET ||
 291                         status == -ESHUTDOWN))
 292                 dev_dbg(&dev->intf->dev,
 293                         "%s - nonzero write interrupt status received: %d\n",
 294                         __func__, status);
 295
 296         dev->interrupt_out_busy = 0;
 297         wake_up_interruptible(&dev->write_wait);
 298 }
 299
 300 /**
 301  *      ld_usb_open
 302  */
 303 static int ld_usb_open(struct inode *inode, struct file *file)
 304 {
 305         struct ld_usb *dev;
 306         int subminor;
 307         int retval;
 308         struct usb_interface *interface;
 309
 310         stream_open(inode, file);
 311         subminor = iminor(inode);
 312
 313         interface = usb_find_interface(&ld_usb_driver, subminor);
 314
 315         if (!interface) {
 316                 printk(KERN_ERR "%s - error, can't find device for minor %d\n",
 317                        __func__, subminor);
 318                 return -ENODEV;
 319         }
 320
 321         dev = usb_get_intfdata(interface);
 322
 323         if (!dev)
 324                 return -ENODEV;
 325
 326         /* lock this device */
 327         if (mutex_lock_interruptible(&dev->mutex))
 328                 return -ERESTARTSYS;
 329
 330         /* allow opening only once */
 331         if (dev->open_count) {
 332                 retval = -EBUSY;
 333                 goto unlock_exit;
 334         }
 335         dev->open_count = 1;
 336
 337         /* initialize in direction */
 338         dev->ring_head = 0;
 339         dev->ring_tail = 0;
 340         dev->buffer_overflow = 0;
 341         usb_fill_int_urb(dev->interrupt_in_urb,
 342                          interface_to_usbdev(interface),
 343                          usb_rcvintpipe(interface_to_usbdev(interface),
 344                                         dev->interrupt_in_endpoint->bEndpointAddress),
 345                          dev->interrupt_in_buffer,
 346                          dev->interrupt_in_endpoint_size,
 347                          ld_usb_interrupt_in_callback,
 348                          dev,
 349                          dev->interrupt_in_interval);
 350
 351         dev->interrupt_in_running = 1;
 352         dev->interrupt_in_done = 0;
 353
 354         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 355         if (retval) {
 356                 dev_err(&interface->dev, "Couldn't submit interrupt_in_urb %d\n", retval);
 357                 dev->interrupt_in_running = 0;
 358                 dev->open_count = 0;
 359                 goto unlock_exit;
 360         }
 361
 362         /* save device in the file's private structure */
 363         file->private_data = dev;
 364
 365 unlock_exit:
 366         mutex_unlock(&dev->mutex);
 367
 368         return retval;
 369 }
 370
 371 /**
 372  *      ld_usb_release
 373  */
 374 static int ld_usb_release(struct inode *inode, struct file *file)
 375 {
 376         struct ld_usb *dev;
 377         int retval = 0;
 378
 379         dev = file->private_data;
 380
 381         if (dev == NULL) {
 382                 retval = -ENODEV;
 383                 goto exit;
 384         }
 385
 386         if (mutex_lock_interruptible(&dev->mutex)) {
 387                 retval = -ERESTARTSYS;
 388                 goto exit;
 389         }
 390
 391         if (dev->open_count != 1) {
 392                 retval = -ENODEV;
 393                 goto unlock_exit;
 394         }
 395         if (dev->intf == NULL) {
 396                 /* the device was unplugged before the file was released */
 397                 mutex_unlock(&dev->mutex);
 398                 /* unlock here as ld_usb_delete frees dev */
 399                 ld_usb_delete(dev);
 400                 goto exit;
 401         }
 402
 403         /* wait until write transfer is finished */
 404         if (dev->interrupt_out_busy)
 405                 wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 406         ld_usb_abort_transfers(dev);
 407         dev->open_count = 0;
 408
 409 unlock_exit:
 410         mutex_unlock(&dev->mutex);
 411
 412 exit:
 413         return retval;
 414 }
 415
 416 /**
 417  *      ld_usb_poll
 418  */
 419 static __poll_t ld_usb_poll(struct file *file, poll_table *wait)
 420 {
 421         struct ld_usb *dev;
 422         __poll_t mask = 0;
 423
 424         dev = file->private_data;
 425
 426         if (!dev->intf)
 427                 return EPOLLERR | EPOLLHUP;
 428
 429         poll_wait(file, &dev->read_wait, wait);
 430         poll_wait(file, &dev->write_wait, wait);
 431
 432         if (dev->ring_head != dev->ring_tail)
 433                 mask |= EPOLLIN | EPOLLRDNORM;
 434         if (!dev->interrupt_out_busy)
 435                 mask |= EPOLLOUT | EPOLLWRNORM;
 436
 437         return mask;
 438 }
 439
 440 /**
 441  *      ld_usb_read
 442  */
 443 static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
 444                            loff_t *ppos)
 445 {
 446         struct ld_usb *dev;
 447         size_t *actual_buffer;
 448         size_t bytes_to_read;
 449         int retval = 0;
 450         int rv;
 451
 452         dev = file->private_data;
 453
 454         /* verify that we actually have some data to read */
 455         if (count == 0)
 456                 goto exit;
 457
 458         /* lock this object */
 459         if (mutex_lock_interruptible(&dev->mutex)) {
 460                 retval = -ERESTARTSYS;
 461                 goto exit;
 462         }
 463
 464         /* verify that the device wasn't unplugged */
 465         if (dev->intf == NULL) {
 466                 retval = -ENODEV;
 467                 printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
 468                 goto unlock_exit;
 469         }
 470
 471         /* wait for data */
 472         spin_lock_irq(&dev->rbsl);
 473         if (dev->ring_head == dev->ring_tail) {
 474                 dev->interrupt_in_done = 0;
 475                 spin_unlock_irq(&dev->rbsl);
 476                 if (file->f_flags & O_NONBLOCK) {
 477                         retval = -EAGAIN;
 478                         goto unlock_exit;
 479                 }
 480                 retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
 481                 if (retval < 0)
 482                         goto unlock_exit;
 483         } else {
 484                 spin_unlock_irq(&dev->rbsl);
 485         }
 486
 487         /* actual_buffer contains actual_length + interrupt_in_buffer */
 488         actual_buffer = (size_t *)(dev->ring_buffer + dev->ring_tail * (sizeof(size_t)+dev->interrupt_in_endpoint_size));
 489         bytes_to_read = min(count, *actual_buffer);
 490         if (bytes_to_read < *actual_buffer)
 491                 dev_warn(&dev->intf->dev, "Read buffer overflow, %zd bytes dropped\n",
 492                          *actual_buffer-bytes_to_read);
 493
 494         /* copy one interrupt_in_buffer from ring_buffer into userspace */
 495         if (copy_to_user(buffer, actual_buffer+1, bytes_to_read)) {
 496                 retval = -EFAULT;
 497                 goto unlock_exit;
 498         }
 499         dev->ring_tail = (dev->ring_tail+1) % ring_buffer_size;
 500
 501         retval = bytes_to_read;
 502
 503         spin_lock_irq(&dev->rbsl);
 504         if (dev->buffer_overflow) {
 505                 dev->buffer_overflow = 0;
 506                 spin_unlock_irq(&dev->rbsl);
 507                 rv = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 508                 if (rv < 0)
 509                         dev->buffer_overflow = 1;
 510         } else {
 511                 spin_unlock_irq(&dev->rbsl);
 512         }
 513
 514 unlock_exit:
 515         /* unlock the device */
 516         mutex_unlock(&dev->mutex);
 517
 518 exit:
 519         return retval;
 520 }
 521
 522 /**
 523  *      ld_usb_write
 524  */
 525 static ssize_t ld_usb_write(struct file *file, const char __user *buffer,
 526                             size_t count, loff_t *ppos)
 527 {
 528         struct ld_usb *dev;
 529         size_t bytes_to_write;
 530         int retval = 0;
 531
 532         dev = file->private_data;
 533
 534         /* verify that we actually have some data to write */
 535         if (count == 0)
 536                 goto exit;
 537
 538         /* lock this object */
 539         if (mutex_lock_interruptible(&dev->mutex)) {
 540                 retval = -ERESTARTSYS;
 541                 goto exit;
 542         }
 543
 544         /* verify that the device wasn't unplugged */
 545         if (dev->intf == NULL) {
 546                 retval = -ENODEV;
 547                 printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
 548                 goto unlock_exit;
 549         }
 550
 551         /* wait until previous transfer is finished */
 552         if (dev->interrupt_out_busy) {
 553                 if (file->f_flags & O_NONBLOCK) {
 554                         retval = -EAGAIN;
 555                         goto unlock_exit;
 556                 }
 557                 retval = wait_event_interruptible(dev->write_wait, !dev->interrupt_out_busy);
 558                 if (retval < 0) {
 559                         goto unlock_exit;
 560                 }
 561         }
 562
 563         /* write the data into interrupt_out_buffer from userspace */
 564         bytes_to_write = min(count, write_buffer_size*dev->interrupt_out_endpoint_size);
 565         if (bytes_to_write < count)
 566                 dev_warn(&dev->intf->dev, "Write buffer overflow, %zd bytes dropped\n", count-bytes_to_write);
 567         dev_dbg(&dev->intf->dev, "%s: count = %zd, bytes_to_write = %zd\n",
 568                 __func__, count, bytes_to_write);
 569
 570         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 571                 retval = -EFAULT;
 572                 goto unlock_exit;
 573         }
 574
 575         if (dev->interrupt_out_endpoint == NULL) {
 576                 /* try HID_REQ_SET_REPORT=9 on control_endpoint instead of interrupt_out_endpoint */
 577                 retval = usb_control_msg(interface_to_usbdev(dev->intf),
 578                                          usb_sndctrlpipe(interface_to_usbdev(dev->intf), 0),
 579                                          9,
 580                                          USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
 581                                          1 << 8, 0,
 582                                          dev->interrupt_out_buffer,
 583                                          bytes_to_write,
 584                                          USB_CTRL_SET_TIMEOUT * HZ);
 585                 if (retval < 0)
 586                         dev_err(&dev->intf->dev,
 587                                 "Couldn't submit HID_REQ_SET_REPORT %d\n",
 588                                 retval);
 589                 goto unlock_exit;
 590         }
 591
 592         /* send off the urb */
 593         usb_fill_int_urb(dev->interrupt_out_urb,
 594                          interface_to_usbdev(dev->intf),
 595                          usb_sndintpipe(interface_to_usbdev(dev->intf),
 596                                         dev->interrupt_out_endpoint->bEndpointAddress),
 597                          dev->interrupt_out_buffer,
 598                          bytes_to_write,
 599                          ld_usb_interrupt_out_callback,
 600                          dev,
 601                          dev->interrupt_out_interval);
 602
 603         dev->interrupt_out_busy = 1;
 604         wmb();
 605
 606         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 607         if (retval) {
 608                 dev->interrupt_out_busy = 0;
 609                 dev_err(&dev->intf->dev,
 610                         "Couldn't submit interrupt_out_urb %d\n", retval);
 611                 goto unlock_exit;
 612         }
 613         retval = bytes_to_write;
 614
 615 unlock_exit:
 616         /* unlock the device */
 617         mutex_unlock(&dev->mutex);
 618
 619 exit:
 620         return retval;
 621 }
 622
 623 /* file operations needed when we register this driver */
 624 static const struct file_operations ld_usb_fops = {
 625         .owner =        THIS_MODULE,
 626         .read  =        ld_usb_read,
 627         .write =        ld_usb_write,
 628         .open =         ld_usb_open,
 629         .release =      ld_usb_release,
 630         .poll =         ld_usb_poll,
 631         .llseek =       no_llseek,
 632 };
 633
 634 /*
 635  * usb class driver info in order to get a minor number from the usb core,
 636  * and to have the device registered with the driver core
 637  */
 638 static struct usb_class_driver ld_usb_class = {
 639         .name =         "ldusb%d",
 640         .fops =         &ld_usb_fops,
 641         .minor_base =   USB_LD_MINOR_BASE,
 642 };
 643
 644 /**
 645  *      ld_usb_probe
 646  *
 647  *      Called by the usb core when a new device is connected that it thinks
 648  *      this driver might be interested in.
 649  */
 650 static int ld_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
 651 {
 652         struct usb_device *udev = interface_to_usbdev(intf);
 653         struct ld_usb *dev = NULL;
 654         struct usb_host_interface *iface_desc;
 655         char *buffer;
 656         int retval = -ENOMEM;
 657         int res;
 658
 659         /* allocate memory for our device state and initialize it */
 660
 661         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 662         if (!dev)
 663                 goto exit;
 664         mutex_init(&dev->mutex);
 665         spin_lock_init(&dev->rbsl);
 666         dev->intf = intf;
 667         init_waitqueue_head(&dev->read_wait);
 668         init_waitqueue_head(&dev->write_wait);
 669
 670         /* workaround for early firmware versions on fast computers */
 671         if ((le16_to_cpu(udev->descriptor.idVendor) == USB_VENDOR_ID_LD) &&
 672             ((le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_CASSY) ||
 673              (le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_COM3LAB)) &&
 674             (le16_to_cpu(udev->descriptor.bcdDevice) <= 0x103)) {
 675                 buffer = kmalloc(256, GFP_KERNEL);
 676                 if (!buffer)
 677                         goto error;
 678                 /* usb_string makes SETUP+STALL to leave always ControlReadLoop */
 679                 usb_string(udev, 255, buffer, 256);
 680                 kfree(buffer);
 681         }
 682
 683         iface_desc = intf->cur_altsetting;
 684
 685         res = usb_find_last_int_in_endpoint(iface_desc,
 686                         &dev->interrupt_in_endpoint);
 687         if (res) {
 688                 dev_err(&intf->dev, "Interrupt in endpoint not found\n");
 689                 retval = res;
 690                 goto error;
 691         }
 692
 693         res = usb_find_last_int_out_endpoint(iface_desc,
 694                         &dev->interrupt_out_endpoint);
 695         if (res)
 696                 dev_warn(&intf->dev, "Interrupt out endpoint not found (using control endpoint instead)\n");
 697
 698         dev->interrupt_in_endpoint_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
 699         dev->ring_buffer =
 700                 kmalloc_array(ring_buffer_size,
 701                               sizeof(size_t) + dev->interrupt_in_endpoint_size,
 702                               GFP_KERNEL);
 703         if (!dev->ring_buffer)
 704                 goto error;
 705         dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 706         if (!dev->interrupt_in_buffer)
 707                 goto error;
 708         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 709         if (!dev->interrupt_in_urb)
 710                 goto error;
 711         dev->interrupt_out_endpoint_size = dev->interrupt_out_endpoint ? usb_endpoint_maxp(dev->interrupt_out_endpoint) :
 712                                                                          udev->descriptor.bMaxPacketSize0;
 713         dev->interrupt_out_buffer =
 714                 kmalloc_array(write_buffer_size,
 715                               dev->interrupt_out_endpoint_size, GFP_KERNEL);
 716         if (!dev->interrupt_out_buffer)
 717                 goto error;
 718         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 719         if (!dev->interrupt_out_urb)
 720                 goto error;
 721         dev->interrupt_in_interval = min_interrupt_in_interval > dev->interrupt_in_endpoint->bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 722         if (dev->interrupt_out_endpoint)
 723                 dev->interrupt_out_interval = min_interrupt_out_interval > dev->interrupt_out_endpoint->bInterval ? min_interrupt_out_interval : 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         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->intf = NULL;
 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