Version:  2.0.40 2.2.26 2.4.37 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2

Linux/drivers/usb/misc/ldusb.c

  1 /**
  2  * Generic USB driver for report based interrupt in/out devices
  3  * like LD Didactic's USB devices. LD Didactic's USB devices are
  4  * HID devices which do not use HID report definitons (they use
  5  * raw interrupt in and our reports only for communication).
  6  *
  7  * This driver uses a ring buffer for time critical reading of
  8  * interrupt in reports and provides read and write methods for
  9  * raw interrupt reports (similar to the Windows HID driver).
 10  * Devices based on the book USB COMPLETE by Jan Axelson may need
 11  * such a compatibility to the Windows HID driver.
 12  *
 13  * Copyright (C) 2005 Michael Hund <mhund@ld-didactic.de>
 14  *
 15  *      This program is free software; you can redistribute it and/or
 16  *      modify it under the terms of the GNU General Public License as
 17  *      published by the Free Software Foundation; either version 2 of
 18  *      the License, or (at your option) any later version.
 19  *
 20  * Derived from Lego USB Tower driver
 21  * Copyright (C) 2003 David Glance <advidgsf@sourceforge.net>
 22  *               2001-2004 Juergen Stuber <starblue@users.sourceforge.net>
 23  */
 24 
 25 #include <linux/kernel.h>
 26 #include <linux/errno.h>
 27 #include <linux/slab.h>
 28 #include <linux/module.h>
 29 #include <linux/mutex.h>
 30 
 31 #include <asm/uaccess.h>
 32 #include <linux/input.h>
 33 #include <linux/usb.h>
 34 #include <linux/poll.h>
 35 
 36 /* Define these values to match your devices */
 37 #define USB_VENDOR_ID_LD                0x0f11  /* USB Vendor ID of LD Didactic GmbH */
 38 #define USB_DEVICE_ID_LD_CASSY          0x1000  /* USB Product ID of CASSY-S modules with 8 bytes endpoint size */
 39 #define USB_DEVICE_ID_LD_CASSY2         0x1001  /* USB Product ID of CASSY-S modules with 64 bytes endpoint size */
 40 #define USB_DEVICE_ID_LD_POCKETCASSY    0x1010  /* USB Product ID of Pocket-CASSY */
 41 #define USB_DEVICE_ID_LD_POCKETCASSY2   0x1011  /* USB Product ID of Pocket-CASSY 2 (reserved) */
 42 #define USB_DEVICE_ID_LD_MOBILECASSY    0x1020  /* USB Product ID of Mobile-CASSY */
 43 #define USB_DEVICE_ID_LD_MOBILECASSY2   0x1021  /* USB Product ID of Mobile-CASSY 2 (reserved) */
 44 #define USB_DEVICE_ID_LD_MICROCASSYVOLTAGE      0x1031  /* USB Product ID of Micro-CASSY Voltage */
 45 #define USB_DEVICE_ID_LD_MICROCASSYCURRENT      0x1032  /* USB Product ID of Micro-CASSY Current */
 46 #define USB_DEVICE_ID_LD_MICROCASSYTIME         0x1033  /* USB Product ID of Micro-CASSY Time (reserved) */
 47 #define USB_DEVICE_ID_LD_MICROCASSYTEMPERATURE  0x1035  /* USB Product ID of Micro-CASSY Temperature */
 48 #define USB_DEVICE_ID_LD_MICROCASSYPH           0x1038  /* USB Product ID of Micro-CASSY pH */
 49 #define USB_DEVICE_ID_LD_JWM            0x1080  /* USB Product ID of Joule and Wattmeter */
 50 #define USB_DEVICE_ID_LD_DMMP           0x1081  /* USB Product ID of Digital Multimeter P (reserved) */
 51 #define USB_DEVICE_ID_LD_UMIP           0x1090  /* USB Product ID of UMI P */
 52 #define USB_DEVICE_ID_LD_UMIC           0x10A0  /* USB Product ID of UMI C */
 53 #define USB_DEVICE_ID_LD_UMIB           0x10B0  /* USB Product ID of UMI B */
 54 #define USB_DEVICE_ID_LD_XRAY           0x1100  /* USB Product ID of X-Ray Apparatus 55481 */
 55 #define USB_DEVICE_ID_LD_XRAY2          0x1101  /* USB Product ID of X-Ray Apparatus 554800 */
 56 #define USB_DEVICE_ID_LD_XRAYCT         0x1110  /* USB Product ID of X-Ray Apparatus CT 554821*/
 57 #define USB_DEVICE_ID_LD_VIDEOCOM       0x1200  /* USB Product ID of VideoCom */
 58 #define USB_DEVICE_ID_LD_MOTOR          0x1210  /* USB Product ID of Motor (reserved) */
 59 #define USB_DEVICE_ID_LD_COM3LAB        0x2000  /* USB Product ID of COM3LAB */
 60 #define USB_DEVICE_ID_LD_TELEPORT       0x2010  /* USB Product ID of Terminal Adapter */
 61 #define USB_DEVICE_ID_LD_NETWORKANALYSER 0x2020 /* USB Product ID of Network Analyser */
 62 #define USB_DEVICE_ID_LD_POWERCONTROL   0x2030  /* USB Product ID of Converter Control Unit */
 63 #define USB_DEVICE_ID_LD_MACHINETEST    0x2040  /* USB Product ID of Machine Test System */
 64 #define USB_DEVICE_ID_LD_MOSTANALYSER   0x2050  /* USB Product ID of MOST Protocol Analyser */
 65 #define USB_DEVICE_ID_LD_MOSTANALYSER2  0x2051  /* USB Product ID of MOST Protocol Analyser 2 */
 66 #define USB_DEVICE_ID_LD_ABSESP         0x2060  /* USB Product ID of ABS ESP */
 67 #define USB_DEVICE_ID_LD_AUTODATABUS    0x2070  /* USB Product ID of Automotive Data Buses */
 68 #define USB_DEVICE_ID_LD_MCT            0x2080  /* USB Product ID of Microcontroller technique */
 69 #define USB_DEVICE_ID_LD_HYBRID         0x2090  /* USB Product ID of Automotive Hybrid */
 70 #define USB_DEVICE_ID_LD_HEATCONTROL    0x20A0  /* USB Product ID of Heat control */
 71 
 72 #ifdef CONFIG_USB_DYNAMIC_MINORS
 73 #define USB_LD_MINOR_BASE       0
 74 #else
 75 #define USB_LD_MINOR_BASE       176
 76 #endif
 77 
 78 /* table of devices that work with this driver */
 79 static const struct usb_device_id ld_usb_table[] = {
 80         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CASSY) },
 81         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CASSY2) },
 82         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POCKETCASSY) },
 83         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POCKETCASSY2) },
 84         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOBILECASSY) },
 85         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOBILECASSY2) },
 86         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYVOLTAGE) },
 87         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYCURRENT) },
 88         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYTIME) },
 89         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYTEMPERATURE) },
 90         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYPH) },
 91         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_JWM) },
 92         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_DMMP) },
 93         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIP) },
 94         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIC) },
 95         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIB) },
 96         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_XRAY) },
 97         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_XRAY2) },
 98         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_VIDEOCOM) },
 99         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOTOR) },
100         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_COM3LAB) },
101         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_TELEPORT) },
102         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_NETWORKANALYSER) },
103         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POWERCONTROL) },
104         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MACHINETEST) },
105         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOSTANALYSER) },
106         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOSTANALYSER2) },
107         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_ABSESP) },
108         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_AUTODATABUS) },
109         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MCT) },
110         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_HYBRID) },
111         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_HEATCONTROL) },
112         { }                                     /* Terminating entry */
113 };
114 MODULE_DEVICE_TABLE(usb, ld_usb_table);
115 MODULE_VERSION("V0.14");
116 MODULE_AUTHOR("Michael Hund <mhund@ld-didactic.de>");
117 MODULE_DESCRIPTION("LD USB Driver");
118 MODULE_LICENSE("GPL");
119 MODULE_SUPPORTED_DEVICE("LD USB Devices");
120 
121 /* All interrupt in transfers are collected in a ring buffer to
122  * avoid racing conditions and get better performance of the driver.
123  */
124 static int ring_buffer_size = 128;
125 module_param(ring_buffer_size, int, 0);
126 MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size in reports");
127 
128 /* The write_buffer can contain more than one interrupt out transfer.
129  */
130 static int write_buffer_size = 10;
131 module_param(write_buffer_size, int, 0);
132 MODULE_PARM_DESC(write_buffer_size, "Write buffer size in reports");
133 
134 /* As of kernel version 2.6.4 ehci-hcd uses an
135  * "only one interrupt transfer per frame" shortcut
136  * to simplify the scheduling of periodic transfers.
137  * This conflicts with our standard 1ms intervals for in and out URBs.
138  * We use default intervals of 2ms for in and 2ms for out transfers,
139  * which should be fast enough.
140  * Increase the interval to allow more devices that do interrupt transfers,
141  * or set to 1 to use the standard interval from the endpoint descriptors.
142  */
143 static int min_interrupt_in_interval = 2;
144 module_param(min_interrupt_in_interval, int, 0);
145 MODULE_PARM_DESC(min_interrupt_in_interval, "Minimum interrupt in interval in ms");
146 
147 static int min_interrupt_out_interval = 2;
148 module_param(min_interrupt_out_interval, int, 0);
149 MODULE_PARM_DESC(min_interrupt_out_interval, "Minimum interrupt out interval in ms");
150 
151 /* Structure to hold all of our device specific stuff */
152 struct ld_usb {
153         struct mutex            mutex;          /* locks this structure */
154         struct usb_interface*   intf;           /* save off the usb interface pointer */
155 
156         int                     open_count;     /* number of times this port has been opened */
157 
158         char*                   ring_buffer;
159         unsigned int            ring_head;
160         unsigned int            ring_tail;
161 
162         wait_queue_head_t       read_wait;
163         wait_queue_head_t       write_wait;
164 
165         char*                   interrupt_in_buffer;
166         struct usb_endpoint_descriptor* interrupt_in_endpoint;
167         struct urb*             interrupt_in_urb;
168         int                     interrupt_in_interval;
169         size_t                  interrupt_in_endpoint_size;
170         int                     interrupt_in_running;
171         int                     interrupt_in_done;
172         int                     buffer_overflow;
173         spinlock_t              rbsl;
174 
175         char*                   interrupt_out_buffer;
176         struct usb_endpoint_descriptor* interrupt_out_endpoint;
177         struct urb*             interrupt_out_urb;
178         int                     interrupt_out_interval;
179         size_t                  interrupt_out_endpoint_size;
180         int                     interrupt_out_busy;
181 };
182 
183 static struct usb_driver ld_usb_driver;
184 
185 /**
186  *      ld_usb_abort_transfers
187  *      aborts transfers and frees associated data structures
188  */
189 static void ld_usb_abort_transfers(struct ld_usb *dev)
190 {
191         /* shutdown transfer */
192         if (dev->interrupt_in_running) {
193                 dev->interrupt_in_running = 0;
194                 if (dev->intf)
195                         usb_kill_urb(dev->interrupt_in_urb);
196         }
197         if (dev->interrupt_out_busy)
198                 if (dev->intf)
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         ld_usb_abort_transfers(dev);
208 
209         /* free data structures */
210         usb_free_urb(dev->interrupt_in_urb);
211         usb_free_urb(dev->interrupt_out_urb);
212         kfree(dev->ring_buffer);
213         kfree(dev->interrupt_in_buffer);
214         kfree(dev->interrupt_out_buffer);
215         kfree(dev);
216 }
217 
218 /**
219  *      ld_usb_interrupt_in_callback
220  */
221 static void ld_usb_interrupt_in_callback(struct urb *urb)
222 {
223         struct ld_usb *dev = urb->context;
224         size_t *actual_buffer;
225         unsigned int next_ring_head;
226         int status = urb->status;
227         int retval;
228 
229         if (status) {
230                 if (status == -ENOENT ||
231                     status == -ECONNRESET ||
232                     status == -ESHUTDOWN) {
233                         goto exit;
234                 } else {
235                         dev_dbg(&dev->intf->dev,
236                                 "%s: nonzero status received: %d\n", __func__,
237                                 status);
238                         spin_lock(&dev->rbsl);
239                         goto resubmit; /* maybe we can recover */
240                 }
241         }
242 
243         spin_lock(&dev->rbsl);
244         if (urb->actual_length > 0) {
245                 next_ring_head = (dev->ring_head+1) % ring_buffer_size;
246                 if (next_ring_head != dev->ring_tail) {
247                         actual_buffer = (size_t*)(dev->ring_buffer + dev->ring_head*(sizeof(size_t)+dev->interrupt_in_endpoint_size));
248                         /* actual_buffer gets urb->actual_length + interrupt_in_buffer */
249                         *actual_buffer = urb->actual_length;
250                         memcpy(actual_buffer+1, dev->interrupt_in_buffer, urb->actual_length);
251                         dev->ring_head = next_ring_head;
252                         dev_dbg(&dev->intf->dev, "%s: received %d bytes\n",
253                                 __func__, urb->actual_length);
254                 } else {
255                         dev_warn(&dev->intf->dev,
256                                  "Ring buffer overflow, %d bytes dropped\n",
257                                  urb->actual_length);
258                         dev->buffer_overflow = 1;
259                 }
260         }
261 
262 resubmit:
263         /* resubmit if we're still running */
264         if (dev->interrupt_in_running && !dev->buffer_overflow && dev->intf) {
265                 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
266                 if (retval) {
267                         dev_err(&dev->intf->dev,
268                                 "usb_submit_urb failed (%d)\n", retval);
269                         dev->buffer_overflow = 1;
270                 }
271         }
272         spin_unlock(&dev->rbsl);
273 exit:
274         dev->interrupt_in_done = 1;
275         wake_up_interruptible(&dev->read_wait);
276 }
277 
278 /**
279  *      ld_usb_interrupt_out_callback
280  */
281 static void ld_usb_interrupt_out_callback(struct urb *urb)
282 {
283         struct ld_usb *dev = urb->context;
284         int status = urb->status;
285 
286         /* sync/async unlink faults aren't errors */
287         if (status && !(status == -ENOENT ||
288                         status == -ECONNRESET ||
289                         status == -ESHUTDOWN))
290                 dev_dbg(&dev->intf->dev,
291                         "%s - nonzero write interrupt status received: %d\n",
292                         __func__, status);
293 
294         dev->interrupt_out_busy = 0;
295         wake_up_interruptible(&dev->write_wait);
296 }
297 
298 /**
299  *      ld_usb_open
300  */
301 static int ld_usb_open(struct inode *inode, struct file *file)
302 {
303         struct ld_usb *dev;
304         int subminor;
305         int retval;
306         struct usb_interface *interface;
307 
308         nonseekable_open(inode, file);
309         subminor = iminor(inode);
310 
311         interface = usb_find_interface(&ld_usb_driver, subminor);
312 
313         if (!interface) {
314                 printk(KERN_ERR "%s - error, can't find device for minor %d\n",
315                        __func__, subminor);
316                 return -ENODEV;
317         }
318 
319         dev = usb_get_intfdata(interface);
320 
321         if (!dev)
322                 return -ENODEV;
323 
324         /* lock this device */
325         if (mutex_lock_interruptible(&dev->mutex))
326                 return -ERESTARTSYS;
327 
328         /* allow opening only once */
329         if (dev->open_count) {
330                 retval = -EBUSY;
331                 goto unlock_exit;
332         }
333         dev->open_count = 1;
334 
335         /* initialize in direction */
336         dev->ring_head = 0;
337         dev->ring_tail = 0;
338         dev->buffer_overflow = 0;
339         usb_fill_int_urb(dev->interrupt_in_urb,
340                          interface_to_usbdev(interface),
341                          usb_rcvintpipe(interface_to_usbdev(interface),
342                                         dev->interrupt_in_endpoint->bEndpointAddress),
343                          dev->interrupt_in_buffer,
344                          dev->interrupt_in_endpoint_size,
345                          ld_usb_interrupt_in_callback,
346                          dev,
347                          dev->interrupt_in_interval);
348 
349         dev->interrupt_in_running = 1;
350         dev->interrupt_in_done = 0;
351 
352         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
353         if (retval) {
354                 dev_err(&interface->dev, "Couldn't submit interrupt_in_urb %d\n", retval);
355                 dev->interrupt_in_running = 0;
356                 dev->open_count = 0;
357                 goto unlock_exit;
358         }
359 
360         /* save device in the file's private structure */
361         file->private_data = dev;
362 
363 unlock_exit:
364         mutex_unlock(&dev->mutex);
365 
366         return retval;
367 }
368 
369 /**
370  *      ld_usb_release
371  */
372 static int ld_usb_release(struct inode *inode, struct file *file)
373 {
374         struct ld_usb *dev;
375         int retval = 0;
376 
377         dev = file->private_data;
378 
379         if (dev == NULL) {
380                 retval = -ENODEV;
381                 goto exit;
382         }
383 
384         if (mutex_lock_interruptible(&dev->mutex)) {
385                 retval = -ERESTARTSYS;
386                 goto exit;
387         }
388 
389         if (dev->open_count != 1) {
390                 retval = -ENODEV;
391                 goto unlock_exit;
392         }
393         if (dev->intf == NULL) {
394                 /* the device was unplugged before the file was released */
395                 mutex_unlock(&dev->mutex);
396                 /* unlock here as ld_usb_delete frees dev */
397                 ld_usb_delete(dev);
398                 goto exit;
399         }
400 
401         /* wait until write transfer is finished */
402         if (dev->interrupt_out_busy)
403                 wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
404         ld_usb_abort_transfers(dev);
405         dev->open_count = 0;
406 
407 unlock_exit:
408         mutex_unlock(&dev->mutex);
409 
410 exit:
411         return retval;
412 }
413 
414 /**
415  *      ld_usb_poll
416  */
417 static unsigned int ld_usb_poll(struct file *file, poll_table *wait)
418 {
419         struct ld_usb *dev;
420         unsigned int mask = 0;
421 
422         dev = file->private_data;
423 
424         if (!dev->intf)
425                 return POLLERR | POLLHUP;
426 
427         poll_wait(file, &dev->read_wait, wait);
428         poll_wait(file, &dev->write_wait, wait);
429 
430         if (dev->ring_head != dev->ring_tail)
431                 mask |= POLLIN | POLLRDNORM;
432         if (!dev->interrupt_out_busy)
433                 mask |= POLLOUT | POLLWRNORM;
434 
435         return mask;
436 }
437 
438 /**
439  *      ld_usb_read
440  */
441 static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
442                            loff_t *ppos)
443 {
444         struct ld_usb *dev;
445         size_t *actual_buffer;
446         size_t bytes_to_read;
447         int retval = 0;
448         int rv;
449 
450         dev = file->private_data;
451 
452         /* verify that we actually have some data to read */
453         if (count == 0)
454                 goto exit;
455 
456         /* lock this object */
457         if (mutex_lock_interruptible(&dev->mutex)) {
458                 retval = -ERESTARTSYS;
459                 goto exit;
460         }
461 
462         /* verify that the device wasn't unplugged */
463         if (dev->intf == NULL) {
464                 retval = -ENODEV;
465                 printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
466                 goto unlock_exit;
467         }
468 
469         /* wait for data */
470         spin_lock_irq(&dev->rbsl);
471         if (dev->ring_head == dev->ring_tail) {
472                 dev->interrupt_in_done = 0;
473                 spin_unlock_irq(&dev->rbsl);
474                 if (file->f_flags & O_NONBLOCK) {
475                         retval = -EAGAIN;
476                         goto unlock_exit;
477                 }
478                 retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
479                 if (retval < 0)
480                         goto unlock_exit;
481         } else {
482                 spin_unlock_irq(&dev->rbsl);
483         }
484 
485         /* actual_buffer contains actual_length + interrupt_in_buffer */
486         actual_buffer = (size_t*)(dev->ring_buffer + dev->ring_tail*(sizeof(size_t)+dev->interrupt_in_endpoint_size));
487         bytes_to_read = min(count, *actual_buffer);
488         if (bytes_to_read < *actual_buffer)
489                 dev_warn(&dev->intf->dev, "Read buffer overflow, %zd bytes dropped\n",
490                          *actual_buffer-bytes_to_read);
491 
492         /* copy one interrupt_in_buffer from ring_buffer into userspace */
493         if (copy_to_user(buffer, actual_buffer+1, bytes_to_read)) {
494                 retval = -EFAULT;
495                 goto unlock_exit;
496         }
497         dev->ring_tail = (dev->ring_tail+1) % ring_buffer_size;
498 
499         retval = bytes_to_read;
500 
501         spin_lock_irq(&dev->rbsl);
502         if (dev->buffer_overflow) {
503                 dev->buffer_overflow = 0;
504                 spin_unlock_irq(&dev->rbsl);
505                 rv = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
506                 if (rv < 0)
507                         dev->buffer_overflow = 1;
508         } else {
509                 spin_unlock_irq(&dev->rbsl);
510         }
511 
512 unlock_exit:
513         /* unlock the device */
514         mutex_unlock(&dev->mutex);
515 
516 exit:
517         return retval;
518 }
519 
520 /**
521  *      ld_usb_write
522  */
523 static ssize_t ld_usb_write(struct file *file, const char __user *buffer,
524                             size_t count, loff_t *ppos)
525 {
526         struct ld_usb *dev;
527         size_t bytes_to_write;
528         int retval = 0;
529 
530         dev = file->private_data;
531 
532         /* verify that we actually have some data to write */
533         if (count == 0)
534                 goto exit;
535 
536         /* lock this object */
537         if (mutex_lock_interruptible(&dev->mutex)) {
538                 retval = -ERESTARTSYS;
539                 goto exit;
540         }
541 
542         /* verify that the device wasn't unplugged */
543         if (dev->intf == NULL) {
544                 retval = -ENODEV;
545                 printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
546                 goto unlock_exit;
547         }
548 
549         /* wait until previous transfer is finished */
550         if (dev->interrupt_out_busy) {
551                 if (file->f_flags & O_NONBLOCK) {
552                         retval = -EAGAIN;
553                         goto unlock_exit;
554                 }
555                 retval = wait_event_interruptible(dev->write_wait, !dev->interrupt_out_busy);
556                 if (retval < 0) {
557                         goto unlock_exit;
558                 }
559         }
560 
561         /* write the data into interrupt_out_buffer from userspace */
562         bytes_to_write = min(count, write_buffer_size*dev->interrupt_out_endpoint_size);
563         if (bytes_to_write < count)
564                 dev_warn(&dev->intf->dev, "Write buffer overflow, %zd bytes dropped\n",count-bytes_to_write);
565         dev_dbg(&dev->intf->dev, "%s: count = %zd, bytes_to_write = %zd\n",
566                 __func__, count, bytes_to_write);
567 
568         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
569                 retval = -EFAULT;
570                 goto unlock_exit;
571         }
572 
573         if (dev->interrupt_out_endpoint == NULL) {
574                 /* try HID_REQ_SET_REPORT=9 on control_endpoint instead of interrupt_out_endpoint */
575                 retval = usb_control_msg(interface_to_usbdev(dev->intf),
576                                          usb_sndctrlpipe(interface_to_usbdev(dev->intf), 0),
577                                          9,
578                                          USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
579                                          1 << 8, 0,
580                                          dev->interrupt_out_buffer,
581                                          bytes_to_write,
582                                          USB_CTRL_SET_TIMEOUT * HZ);
583                 if (retval < 0)
584                         dev_err(&dev->intf->dev,
585                                 "Couldn't submit HID_REQ_SET_REPORT %d\n",
586                                 retval);
587                 goto unlock_exit;
588         }
589 
590         /* send off the urb */
591         usb_fill_int_urb(dev->interrupt_out_urb,
592                          interface_to_usbdev(dev->intf),
593                          usb_sndintpipe(interface_to_usbdev(dev->intf),
594                                         dev->interrupt_out_endpoint->bEndpointAddress),
595                          dev->interrupt_out_buffer,
596                          bytes_to_write,
597                          ld_usb_interrupt_out_callback,
598                          dev,
599                          dev->interrupt_out_interval);
600 
601         dev->interrupt_out_busy = 1;
602         wmb();
603 
604         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
605         if (retval) {
606                 dev->interrupt_out_busy = 0;
607                 dev_err(&dev->intf->dev,
608                         "Couldn't submit interrupt_out_urb %d\n", retval);
609                 goto unlock_exit;
610         }
611         retval = bytes_to_write;
612 
613 unlock_exit:
614         /* unlock the device */
615         mutex_unlock(&dev->mutex);
616 
617 exit:
618         return retval;
619 }
620 
621 /* file operations needed when we register this driver */
622 static const struct file_operations ld_usb_fops = {
623         .owner =        THIS_MODULE,
624         .read  =        ld_usb_read,
625         .write =        ld_usb_write,
626         .open =         ld_usb_open,
627         .release =      ld_usb_release,
628         .poll =         ld_usb_poll,
629         .llseek =       no_llseek,
630 };
631 
632 /*
633  * usb class driver info in order to get a minor number from the usb core,
634  * and to have the device registered with the driver core
635  */
636 static struct usb_class_driver ld_usb_class = {
637         .name =         "ldusb%d",
638         .fops =         &ld_usb_fops,
639         .minor_base =   USB_LD_MINOR_BASE,
640 };
641 
642 /**
643  *      ld_usb_probe
644  *
645  *      Called by the usb core when a new device is connected that it thinks
646  *      this driver might be interested in.
647  */
648 static int ld_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
649 {
650         struct usb_device *udev = interface_to_usbdev(intf);
651         struct ld_usb *dev = NULL;
652         struct usb_host_interface *iface_desc;
653         struct usb_endpoint_descriptor *endpoint;
654         char *buffer;
655         int i;
656         int retval = -ENOMEM;
657 
658         /* allocate memory for our device state and initialize it */
659 
660         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
661         if (dev == NULL) {
662                 dev_err(&intf->dev, "Out of memory\n");
663                 goto exit;
664         }
665         mutex_init(&dev->mutex);
666         spin_lock_init(&dev->rbsl);
667         dev->intf = intf;
668         init_waitqueue_head(&dev->read_wait);
669         init_waitqueue_head(&dev->write_wait);
670 
671         /* workaround for early firmware versions on fast computers */
672         if ((le16_to_cpu(udev->descriptor.idVendor) == USB_VENDOR_ID_LD) &&
673             ((le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_CASSY) ||
674              (le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_COM3LAB)) &&
675             (le16_to_cpu(udev->descriptor.bcdDevice) <= 0x103)) {
676                 buffer = kmalloc(256, GFP_KERNEL);
677                 if (buffer == NULL) {
678                         dev_err(&intf->dev, "Couldn't allocate string buffer\n");
679                         goto error;
680                 }
681                 /* usb_string makes SETUP+STALL to leave always ControlReadLoop */
682                 usb_string(udev, 255, buffer, 256);
683                 kfree(buffer);
684         }
685 
686         iface_desc = intf->cur_altsetting;
687 
688         /* set up the endpoint information */
689         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
690                 endpoint = &iface_desc->endpoint[i].desc;
691 
692                 if (usb_endpoint_is_int_in(endpoint))
693                         dev->interrupt_in_endpoint = endpoint;
694 
695                 if (usb_endpoint_is_int_out(endpoint))
696                         dev->interrupt_out_endpoint = endpoint;
697         }
698         if (dev->interrupt_in_endpoint == NULL) {
699                 dev_err(&intf->dev, "Interrupt in endpoint not found\n");
700                 goto error;
701         }
702         if (dev->interrupt_out_endpoint == NULL)
703                 dev_warn(&intf->dev, "Interrupt out endpoint not found (using control endpoint instead)\n");
704 
705         dev->interrupt_in_endpoint_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
706         dev->ring_buffer = kmalloc(ring_buffer_size*(sizeof(size_t)+dev->interrupt_in_endpoint_size), GFP_KERNEL);
707         if (!dev->ring_buffer) {
708                 dev_err(&intf->dev, "Couldn't allocate ring_buffer\n");
709                 goto error;
710         }
711         dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
712         if (!dev->interrupt_in_buffer) {
713                 dev_err(&intf->dev, "Couldn't allocate interrupt_in_buffer\n");
714                 goto error;
715         }
716         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
717         if (!dev->interrupt_in_urb) {
718                 dev_err(&intf->dev, "Couldn't allocate interrupt_in_urb\n");
719                 goto error;
720         }
721         dev->interrupt_out_endpoint_size = dev->interrupt_out_endpoint ? usb_endpoint_maxp(dev->interrupt_out_endpoint) :
722                                                                          udev->descriptor.bMaxPacketSize0;
723         dev->interrupt_out_buffer = kmalloc(write_buffer_size*dev->interrupt_out_endpoint_size, GFP_KERNEL);
724         if (!dev->interrupt_out_buffer) {
725                 dev_err(&intf->dev, "Couldn't allocate interrupt_out_buffer\n");
726                 goto error;
727         }
728         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
729         if (!dev->interrupt_out_urb) {
730                 dev_err(&intf->dev, "Couldn't allocate interrupt_out_urb\n");
731                 goto error;
732         }
733         dev->interrupt_in_interval = min_interrupt_in_interval > dev->interrupt_in_endpoint->bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
734         if (dev->interrupt_out_endpoint)
735                 dev->interrupt_out_interval = min_interrupt_out_interval > dev->interrupt_out_endpoint->bInterval ? min_interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
736 
737         /* we can register the device now, as it is ready */
738         usb_set_intfdata(intf, dev);
739 
740         retval = usb_register_dev(intf, &ld_usb_class);
741         if (retval) {
742                 /* something prevented us from registering this driver */
743                 dev_err(&intf->dev, "Not able to get a minor for this device.\n");
744                 usb_set_intfdata(intf, NULL);
745                 goto error;
746         }
747 
748         /* let the user know what node this device is now attached to */
749         dev_info(&intf->dev, "LD USB Device #%d now attached to major %d minor %d\n",
750                 (intf->minor - USB_LD_MINOR_BASE), USB_MAJOR, intf->minor);
751 
752 exit:
753         return retval;
754 
755 error:
756         ld_usb_delete(dev);
757 
758         return retval;
759 }
760 
761 /**
762  *      ld_usb_disconnect
763  *
764  *      Called by the usb core when the device is removed from the system.
765  */
766 static void ld_usb_disconnect(struct usb_interface *intf)
767 {
768         struct ld_usb *dev;
769         int minor;
770 
771         dev = usb_get_intfdata(intf);
772         usb_set_intfdata(intf, NULL);
773 
774         minor = intf->minor;
775 
776         /* give back our minor */
777         usb_deregister_dev(intf, &ld_usb_class);
778 
779         mutex_lock(&dev->mutex);
780 
781         /* if the device is not opened, then we clean up right now */
782         if (!dev->open_count) {
783                 mutex_unlock(&dev->mutex);
784                 ld_usb_delete(dev);
785         } else {
786                 dev->intf = NULL;
787                 /* wake up pollers */
788                 wake_up_interruptible_all(&dev->read_wait);
789                 wake_up_interruptible_all(&dev->write_wait);
790                 mutex_unlock(&dev->mutex);
791         }
792 
793         dev_info(&intf->dev, "LD USB Device #%d now disconnected\n",
794                  (minor - USB_LD_MINOR_BASE));
795 }
796 
797 /* usb specific object needed to register this driver with the usb subsystem */
798 static struct usb_driver ld_usb_driver = {
799         .name =         "ldusb",
800         .probe =        ld_usb_probe,
801         .disconnect =   ld_usb_disconnect,
802         .id_table =     ld_usb_table,
803 };
804 
805 module_usb_driver(ld_usb_driver);
806 
807 

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