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         mutex_lock(&dev->mutex);
 384
 385         if (dev->open_count != 1) {
 386                 retval = -ENODEV;
 387                 goto unlock_exit;
 388         }
 389         if (dev->disconnected) {
 390                 /* the device was unplugged before the file was released */
 391                 mutex_unlock(&dev->mutex);
 392                 /* unlock here as ld_usb_delete frees dev */
 393                 ld_usb_delete(dev);
 394                 goto exit;
 395         }
 396
 397         /* wait until write transfer is finished */
 398         if (dev->interrupt_out_busy)
 399                 wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 400         ld_usb_abort_transfers(dev);
 401         dev->open_count = 0;
 402
 403 unlock_exit:
 404         mutex_unlock(&dev->mutex);
 405
 406 exit:
 407         return retval;
 408 }
 409
 410 /*
 411  *      ld_usb_poll
 412  */
 413 static __poll_t ld_usb_poll(struct file *file, poll_table *wait)
 414 {
 415         struct ld_usb *dev;
 416         __poll_t mask = 0;
 417
 418         dev = file->private_data;
 419
 420         if (dev->disconnected)
 421                 return EPOLLERR | EPOLLHUP;
 422
 423         poll_wait(file, &dev->read_wait, wait);
 424         poll_wait(file, &dev->write_wait, wait);
 425
 426         if (dev->ring_head != dev->ring_tail)
 427                 mask |= EPOLLIN | EPOLLRDNORM;
 428         if (!dev->interrupt_out_busy)
 429                 mask |= EPOLLOUT | EPOLLWRNORM;
 430
 431         return mask;
 432 }
 433
 434 /*
 435  *      ld_usb_read
 436  */
 437 static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
 438                            loff_t *ppos)
 439 {
 440         struct ld_usb *dev;
 441         size_t *actual_buffer;
 442         size_t bytes_to_read;
 443         int retval = 0;
 444         int rv;
 445
 446         dev = file->private_data;
 447
 448         /* verify that we actually have some data to read */
 449         if (count == 0)
 450                 goto exit;
 451
 452         /* lock this object */
 453         if (mutex_lock_interruptible(&dev->mutex)) {
 454                 retval = -ERESTARTSYS;
 455                 goto exit;
 456         }
 457
 458         /* verify that the device wasn't unplugged */
 459         if (dev->disconnected) {
 460                 retval = -ENODEV;
 461                 printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
 462                 goto unlock_exit;
 463         }
 464
 465         /* wait for data */
 466         spin_lock_irq(&dev->rbsl);
 467         while (dev->ring_head == dev->ring_tail) {
 468                 dev->interrupt_in_done = 0;
 469                 spin_unlock_irq(&dev->rbsl);
 470                 if (file->f_flags & O_NONBLOCK) {
 471                         retval = -EAGAIN;
 472                         goto unlock_exit;
 473                 }
 474                 retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
 475                 if (retval < 0)
 476                         goto unlock_exit;
 477
 478                 spin_lock_irq(&dev->rbsl);
 479         }
 480         spin_unlock_irq(&dev->rbsl);
 481
 482         /* actual_buffer contains actual_length + interrupt_in_buffer */
 483         actual_buffer = (size_t *)(dev->ring_buffer + dev->ring_tail * (sizeof(size_t)+dev->interrupt_in_endpoint_size));
 484         if (*actual_buffer > dev->interrupt_in_endpoint_size) {
 485                 retval = -EIO;
 486                 goto unlock_exit;
 487         }
 488         bytes_to_read = min(count, *actual_buffer);
 489         if (bytes_to_read < *actual_buffer)
 490                 dev_warn(&dev->intf->dev, "Read buffer overflow, %zu bytes dropped\n",
 491                          *actual_buffer-bytes_to_read);
 492
 493         /* copy one interrupt_in_buffer from ring_buffer into userspace */
 494         if (copy_to_user(buffer, actual_buffer+1, bytes_to_read)) {
 495                 retval = -EFAULT;
 496                 goto unlock_exit;
 497         }
 498         retval = bytes_to_read;
 499
 500         spin_lock_irq(&dev->rbsl);
 501         dev->ring_tail = (dev->ring_tail + 1) % ring_buffer_size;
 502
 503         if (dev->buffer_overflow) {
 504                 dev->buffer_overflow = 0;
 505                 spin_unlock_irq(&dev->rbsl);
 506                 rv = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 507                 if (rv < 0)
 508                         dev->buffer_overflow = 1;
 509         } else {
 510                 spin_unlock_irq(&dev->rbsl);
 511         }
 512
 513 unlock_exit:
 514         /* unlock the device */
 515         mutex_unlock(&dev->mutex);
 516
 517 exit:
 518         return retval;
 519 }
 520
 521 /*
 522  *      ld_usb_write
 523  */
 524 static ssize_t ld_usb_write(struct file *file, const char __user *buffer,
 525                             size_t count, loff_t *ppos)
 526 {
 527         struct ld_usb *dev;
 528         size_t bytes_to_write;
 529         int retval = 0;
 530
 531         dev = file->private_data;
 532
 533         /* verify that we actually have some data to write */
 534         if (count == 0)
 535                 goto exit;
 536
 537         /* lock this object */
 538         if (mutex_lock_interruptible(&dev->mutex)) {
 539                 retval = -ERESTARTSYS;
 540                 goto exit;
 541         }
 542
 543         /* verify that the device wasn't unplugged */
 544         if (dev->disconnected) {
 545                 retval = -ENODEV;
 546                 printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
 547                 goto unlock_exit;
 548         }
 549
 550         /* wait until previous transfer is finished */
 551         if (dev->interrupt_out_busy) {
 552                 if (file->f_flags & O_NONBLOCK) {
 553                         retval = -EAGAIN;
 554                         goto unlock_exit;
 555                 }
 556                 retval = wait_event_interruptible(dev->write_wait, !dev->interrupt_out_busy);
 557                 if (retval < 0) {
 558                         goto unlock_exit;
 559                 }
 560         }
 561
 562         /* write the data into interrupt_out_buffer from userspace */
 563         bytes_to_write = min(count, write_buffer_size*dev->interrupt_out_endpoint_size);
 564         if (bytes_to_write < count)
 565                 dev_warn(&dev->intf->dev, "Write buffer overflow, %zu bytes dropped\n",
 566                         count - bytes_to_write);
 567         dev_dbg(&dev->intf->dev, "%s: count = %zu, bytes_to_write = %zu\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);
 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 = kcalloc(ring_buffer_size,
 700                         sizeof(size_t) + dev->interrupt_in_endpoint_size,
 701                         GFP_KERNEL);
 702         if (!dev->ring_buffer)
 703                 goto error;
 704         dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 705         if (!dev->interrupt_in_buffer)
 706                 goto error;
 707         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 708         if (!dev->interrupt_in_urb)
 709                 goto error;
 710         dev->interrupt_out_endpoint_size = dev->interrupt_out_endpoint ? usb_endpoint_maxp(dev->interrupt_out_endpoint) :
 711                                                                          udev->descriptor.bMaxPacketSize0;
 712         dev->interrupt_out_buffer =
 713                 kmalloc_array(write_buffer_size,
 714                               dev->interrupt_out_endpoint_size, GFP_KERNEL);
 715         if (!dev->interrupt_out_buffer)
 716                 goto error;
 717         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 718         if (!dev->interrupt_out_urb)
 719                 goto error;
 720         dev->interrupt_in_interval = min_interrupt_in_interval > dev->interrupt_in_endpoint->bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 721         if (dev->interrupt_out_endpoint)
 722                 dev->interrupt_out_interval = min_interrupt_out_interval > dev->interrupt_out_endpoint->bInterval ? min_interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 723
 724         /* we can register the device now, as it is ready */
 725         usb_set_intfdata(intf, dev);
 726
 727         retval = usb_register_dev(intf, &ld_usb_class);
 728         if (retval) {
 729                 /* something prevented us from registering this driver */
 730                 dev_err(&intf->dev, "Not able to get a minor for this device.\n");
 731                 usb_set_intfdata(intf, NULL);
 732                 goto error;
 733         }
 734
 735         /* let the user know what node this device is now attached to */
 736         dev_info(&intf->dev, "LD USB Device #%d now attached to major %d minor %d\n",
 737                 (intf->minor - USB_LD_MINOR_BASE), USB_MAJOR, intf->minor);
 738
 739 exit:
 740         return retval;
 741
 742 error:
 743         ld_usb_delete(dev);
 744
 745         return retval;
 746 }
 747
 748 /*
 749  *      ld_usb_disconnect
 750  *
 751  *      Called by the usb core when the device is removed from the system.
 752  */
 753 static void ld_usb_disconnect(struct usb_interface *intf)
 754 {
 755         struct ld_usb *dev;
 756         int minor;
 757
 758         dev = usb_get_intfdata(intf);
 759         usb_set_intfdata(intf, NULL);
 760
 761         minor = intf->minor;
 762
 763         /* give back our minor */
 764         usb_deregister_dev(intf, &ld_usb_class);
 765
 766         usb_poison_urb(dev->interrupt_in_urb);
 767         usb_poison_urb(dev->interrupt_out_urb);
 768
 769         mutex_lock(&dev->mutex);
 770
 771         /* if the device is not opened, then we clean up right now */
 772         if (!dev->open_count) {
 773                 mutex_unlock(&dev->mutex);
 774                 ld_usb_delete(dev);
 775         } else {
 776                 dev->disconnected = 1;
 777                 /* wake up pollers */
 778                 wake_up_interruptible_all(&dev->read_wait);
 779                 wake_up_interruptible_all(&dev->write_wait);
 780                 mutex_unlock(&dev->mutex);
 781         }
 782
 783         dev_info(&intf->dev, "LD USB Device #%d now disconnected\n",
 784                  (minor - USB_LD_MINOR_BASE));
 785 }
 786
 787 /* usb specific object needed to register this driver with the usb subsystem */
 788 static struct usb_driver ld_usb_driver = {
 789         .name =         "ldusb",
 790         .probe =        ld_usb_probe,
 791         .disconnect =   ld_usb_disconnect,
 792         .id_table =     ld_usb_table,
 793 };
 794
 795 module_usb_driver(ld_usb_driver);
 796