xref: /linux/drivers/usb/misc/ldusb.c (revision 14b42963f64b98ab61fa9723c03d71aa5ef4f862)
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  * V0.1  (mh) Initial version
25  * V0.11 (mh) Added raw support for HID 1.0 devices (no interrupt out endpoint)
26  * V0.12 (mh) Added kmalloc check for string buffer
27  * V0.13 (mh) Added support for LD X-Ray and Machine Test System
28  */
29 
30 #include <linux/kernel.h>
31 #include <linux/errno.h>
32 #include <linux/init.h>
33 #include <linux/slab.h>
34 #include <linux/module.h>
35 #include <linux/mutex.h>
36 
37 #include <asm/uaccess.h>
38 #include <linux/input.h>
39 #include <linux/usb.h>
40 #include <linux/poll.h>
41 
42 /* Define these values to match your devices */
43 #define USB_VENDOR_ID_LD		0x0f11	/* USB Vendor ID of LD Didactic GmbH */
44 #define USB_DEVICE_ID_LD_CASSY		0x1000	/* USB Product ID of CASSY-S */
45 #define USB_DEVICE_ID_LD_POCKETCASSY	0x1010	/* USB Product ID of Pocket-CASSY */
46 #define USB_DEVICE_ID_LD_MOBILECASSY	0x1020	/* USB Product ID of Mobile-CASSY */
47 #define USB_DEVICE_ID_LD_JWM		0x1080	/* USB Product ID of Joule and Wattmeter */
48 #define USB_DEVICE_ID_LD_DMMP		0x1081	/* USB Product ID of Digital Multimeter P (reserved) */
49 #define USB_DEVICE_ID_LD_UMIP		0x1090	/* USB Product ID of UMI P */
50 #define USB_DEVICE_ID_LD_XRAY1		0x1100	/* USB Product ID of X-Ray Apparatus */
51 #define USB_DEVICE_ID_LD_XRAY2		0x1101	/* USB Product ID of X-Ray Apparatus */
52 #define USB_DEVICE_ID_LD_VIDEOCOM	0x1200	/* USB Product ID of VideoCom */
53 #define USB_DEVICE_ID_LD_COM3LAB	0x2000	/* USB Product ID of COM3LAB */
54 #define USB_DEVICE_ID_LD_TELEPORT	0x2010	/* USB Product ID of Terminal Adapter */
55 #define USB_DEVICE_ID_LD_NETWORKANALYSER 0x2020	/* USB Product ID of Network Analyser */
56 #define USB_DEVICE_ID_LD_POWERCONTROL	0x2030	/* USB Product ID of Converter Control Unit */
57 #define USB_DEVICE_ID_LD_MACHINETEST	0x2040	/* USB Product ID of Machine Test System */
58 
59 #define USB_VENDOR_ID_VERNIER		0x08f7
60 #define USB_DEVICE_ID_VERNIER_LABPRO	0x0001
61 #define USB_DEVICE_ID_VERNIER_GOTEMP	0x0002
62 #define USB_DEVICE_ID_VERNIER_SKIP	0x0003
63 #define USB_DEVICE_ID_VERNIER_CYCLOPS	0x0004
64 
65 
66 #ifdef CONFIG_USB_DYNAMIC_MINORS
67 #define USB_LD_MINOR_BASE	0
68 #else
69 #define USB_LD_MINOR_BASE	176
70 #endif
71 
72 /* table of devices that work with this driver */
73 static struct usb_device_id ld_usb_table [] = {
74 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CASSY) },
75 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POCKETCASSY) },
76 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOBILECASSY) },
77 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_JWM) },
78 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_DMMP) },
79 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIP) },
80 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_XRAY1) },
81 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_XRAY2) },
82 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_VIDEOCOM) },
83 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_COM3LAB) },
84 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_TELEPORT) },
85 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_NETWORKANALYSER) },
86 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POWERCONTROL) },
87 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MACHINETEST) },
88 	{ USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_LABPRO) },
89 	{ USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_GOTEMP) },
90 	{ USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_SKIP) },
91 	{ USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_CYCLOPS) },
92 	{ }					/* Terminating entry */
93 };
94 MODULE_DEVICE_TABLE(usb, ld_usb_table);
95 MODULE_VERSION("V0.13");
96 MODULE_AUTHOR("Michael Hund <mhund@ld-didactic.de>");
97 MODULE_DESCRIPTION("LD USB Driver");
98 MODULE_LICENSE("GPL");
99 MODULE_SUPPORTED_DEVICE("LD USB Devices");
100 
101 #ifdef CONFIG_USB_DEBUG
102 	static int debug = 1;
103 #else
104 	static int debug = 0;
105 #endif
106 
107 /* Use our own dbg macro */
108 #define dbg_info(dev, format, arg...) do { if (debug) dev_info(dev , format , ## arg); } while (0)
109 
110 /* Module parameters */
111 module_param(debug, int, S_IRUGO | S_IWUSR);
112 MODULE_PARM_DESC(debug, "Debug enabled or not");
113 
114 /* All interrupt in transfers are collected in a ring buffer to
115  * avoid racing conditions and get better performance of the driver.
116  */
117 static int ring_buffer_size = 128;
118 module_param(ring_buffer_size, int, 0);
119 MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size in reports");
120 
121 /* The write_buffer can contain more than one interrupt out transfer.
122  */
123 static int write_buffer_size = 10;
124 module_param(write_buffer_size, int, 0);
125 MODULE_PARM_DESC(write_buffer_size, "Write buffer size in reports");
126 
127 /* As of kernel version 2.6.4 ehci-hcd uses an
128  * "only one interrupt transfer per frame" shortcut
129  * to simplify the scheduling of periodic transfers.
130  * This conflicts with our standard 1ms intervals for in and out URBs.
131  * We use default intervals of 2ms for in and 2ms for out transfers,
132  * which should be fast enough.
133  * Increase the interval to allow more devices that do interrupt transfers,
134  * or set to 1 to use the standard interval from the endpoint descriptors.
135  */
136 static int min_interrupt_in_interval = 2;
137 module_param(min_interrupt_in_interval, int, 0);
138 MODULE_PARM_DESC(min_interrupt_in_interval, "Minimum interrupt in interval in ms");
139 
140 static int min_interrupt_out_interval = 2;
141 module_param(min_interrupt_out_interval, int, 0);
142 MODULE_PARM_DESC(min_interrupt_out_interval, "Minimum interrupt out interval in ms");
143 
144 /* Structure to hold all of our device specific stuff */
145 struct ld_usb {
146 	struct semaphore	sem;		/* locks this structure */
147 	struct usb_interface*	intf;		/* save off the usb interface pointer */
148 
149 	int			open_count;	/* number of times this port has been opened */
150 
151 	char*			ring_buffer;
152 	unsigned int		ring_head;
153 	unsigned int		ring_tail;
154 
155 	wait_queue_head_t	read_wait;
156 	wait_queue_head_t	write_wait;
157 
158 	char*			interrupt_in_buffer;
159 	struct usb_endpoint_descriptor* interrupt_in_endpoint;
160 	struct urb*		interrupt_in_urb;
161 	int			interrupt_in_interval;
162 	size_t			interrupt_in_endpoint_size;
163 	int			interrupt_in_running;
164 	int			interrupt_in_done;
165 
166 	char*			interrupt_out_buffer;
167 	struct usb_endpoint_descriptor* interrupt_out_endpoint;
168 	struct urb*		interrupt_out_urb;
169 	int			interrupt_out_interval;
170 	size_t			interrupt_out_endpoint_size;
171 	int			interrupt_out_busy;
172 };
173 
174 /* prevent races between open() and disconnect() */
175 static DEFINE_MUTEX(disconnect_mutex);
176 
177 static struct usb_driver ld_usb_driver;
178 
179 /**
180  *	ld_usb_abort_transfers
181  *      aborts transfers and frees associated data structures
182  */
183 static void ld_usb_abort_transfers(struct ld_usb *dev)
184 {
185 	/* shutdown transfer */
186 	if (dev->interrupt_in_running) {
187 		dev->interrupt_in_running = 0;
188 		if (dev->intf)
189 			usb_kill_urb(dev->interrupt_in_urb);
190 	}
191 	if (dev->interrupt_out_busy)
192 		if (dev->intf)
193 			usb_kill_urb(dev->interrupt_out_urb);
194 }
195 
196 /**
197  *	ld_usb_delete
198  */
199 static void ld_usb_delete(struct ld_usb *dev)
200 {
201 	ld_usb_abort_transfers(dev);
202 
203 	/* free data structures */
204 	usb_free_urb(dev->interrupt_in_urb);
205 	usb_free_urb(dev->interrupt_out_urb);
206 	kfree(dev->ring_buffer);
207 	kfree(dev->interrupt_in_buffer);
208 	kfree(dev->interrupt_out_buffer);
209 	kfree(dev);
210 }
211 
212 /**
213  *	ld_usb_interrupt_in_callback
214  */
215 static void ld_usb_interrupt_in_callback(struct urb *urb, struct pt_regs *regs)
216 {
217 	struct ld_usb *dev = urb->context;
218 	size_t *actual_buffer;
219 	unsigned int next_ring_head;
220 	int retval;
221 
222 	if (urb->status) {
223 		if (urb->status == -ENOENT ||
224 		    urb->status == -ECONNRESET ||
225 		    urb->status == -ESHUTDOWN) {
226 			goto exit;
227 		} else {
228 			dbg_info(&dev->intf->dev, "%s: nonzero status received: %d\n",
229 				 __FUNCTION__, urb->status);
230 			goto resubmit; /* maybe we can recover */
231 		}
232 	}
233 
234 	if (urb->actual_length > 0) {
235 		next_ring_head = (dev->ring_head+1) % ring_buffer_size;
236 		if (next_ring_head != dev->ring_tail) {
237 			actual_buffer = (size_t*)(dev->ring_buffer + dev->ring_head*(sizeof(size_t)+dev->interrupt_in_endpoint_size));
238 			/* actual_buffer gets urb->actual_length + interrupt_in_buffer */
239 			*actual_buffer = urb->actual_length;
240 			memcpy(actual_buffer+1, dev->interrupt_in_buffer, urb->actual_length);
241 			dev->ring_head = next_ring_head;
242 			dbg_info(&dev->intf->dev, "%s: received %d bytes\n",
243 				 __FUNCTION__, urb->actual_length);
244 		} else
245 			dev_warn(&dev->intf->dev,
246 				 "Ring buffer overflow, %d bytes dropped\n",
247 				 urb->actual_length);
248 	}
249 
250 resubmit:
251 	/* resubmit if we're still running */
252 	if (dev->interrupt_in_running && dev->intf) {
253 		retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
254 		if (retval)
255 			dev_err(&dev->intf->dev,
256 				"usb_submit_urb failed (%d)\n", retval);
257 	}
258 
259 exit:
260 	dev->interrupt_in_done = 1;
261 	wake_up_interruptible(&dev->read_wait);
262 }
263 
264 /**
265  *	ld_usb_interrupt_out_callback
266  */
267 static void ld_usb_interrupt_out_callback(struct urb *urb, struct pt_regs *regs)
268 {
269 	struct ld_usb *dev = urb->context;
270 
271 	/* sync/async unlink faults aren't errors */
272 	if (urb->status && !(urb->status == -ENOENT ||
273 			     urb->status == -ECONNRESET ||
274 			     urb->status == -ESHUTDOWN))
275 		dbg_info(&dev->intf->dev,
276 			 "%s - nonzero write interrupt status received: %d\n",
277 			 __FUNCTION__, urb->status);
278 
279 	dev->interrupt_out_busy = 0;
280 	wake_up_interruptible(&dev->write_wait);
281 }
282 
283 /**
284  *	ld_usb_open
285  */
286 static int ld_usb_open(struct inode *inode, struct file *file)
287 {
288 	struct ld_usb *dev;
289 	int subminor;
290 	int retval = 0;
291 	struct usb_interface *interface;
292 
293 	nonseekable_open(inode, file);
294 	subminor = iminor(inode);
295 
296 	mutex_lock(&disconnect_mutex);
297 
298 	interface = usb_find_interface(&ld_usb_driver, subminor);
299 
300 	if (!interface) {
301 		err("%s - error, can't find device for minor %d\n",
302 		     __FUNCTION__, subminor);
303 		retval = -ENODEV;
304 		goto unlock_disconnect_exit;
305 	}
306 
307 	dev = usb_get_intfdata(interface);
308 
309 	if (!dev) {
310 		retval = -ENODEV;
311 		goto unlock_disconnect_exit;
312 	}
313 
314 	/* lock this device */
315 	if (down_interruptible(&dev->sem)) {
316 		retval = -ERESTARTSYS;
317 		goto unlock_disconnect_exit;
318 	}
319 
320 	/* allow opening only once */
321 	if (dev->open_count) {
322 		retval = -EBUSY;
323 		goto unlock_exit;
324 	}
325 	dev->open_count = 1;
326 
327 	/* initialize in direction */
328 	dev->ring_head = 0;
329 	dev->ring_tail = 0;
330 	usb_fill_int_urb(dev->interrupt_in_urb,
331 			 interface_to_usbdev(interface),
332 			 usb_rcvintpipe(interface_to_usbdev(interface),
333 					dev->interrupt_in_endpoint->bEndpointAddress),
334 			 dev->interrupt_in_buffer,
335 			 dev->interrupt_in_endpoint_size,
336 			 ld_usb_interrupt_in_callback,
337 			 dev,
338 			 dev->interrupt_in_interval);
339 
340 	dev->interrupt_in_running = 1;
341 	dev->interrupt_in_done = 0;
342 
343 	retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
344 	if (retval) {
345 		dev_err(&interface->dev, "Couldn't submit interrupt_in_urb %d\n", retval);
346 		dev->interrupt_in_running = 0;
347 		dev->open_count = 0;
348 		goto unlock_exit;
349 	}
350 
351 	/* save device in the file's private structure */
352 	file->private_data = dev;
353 
354 unlock_exit:
355 	up(&dev->sem);
356 
357 unlock_disconnect_exit:
358 	mutex_unlock(&disconnect_mutex);
359 
360 	return retval;
361 }
362 
363 /**
364  *	ld_usb_release
365  */
366 static int ld_usb_release(struct inode *inode, struct file *file)
367 {
368 	struct ld_usb *dev;
369 	int retval = 0;
370 
371 	dev = file->private_data;
372 
373 	if (dev == NULL) {
374 		retval = -ENODEV;
375 		goto exit;
376 	}
377 
378 	if (down_interruptible(&dev->sem)) {
379 		retval = -ERESTARTSYS;
380 		goto exit;
381 	}
382 
383 	if (dev->open_count != 1) {
384 		retval = -ENODEV;
385 		goto unlock_exit;
386 	}
387 	if (dev->intf == NULL) {
388 		/* the device was unplugged before the file was released */
389 		up(&dev->sem);
390 		/* unlock here as ld_usb_delete frees dev */
391 		ld_usb_delete(dev);
392 		goto exit;
393 	}
394 
395 	/* wait until write transfer is finished */
396 	if (dev->interrupt_out_busy)
397 		wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
398 	ld_usb_abort_transfers(dev);
399 	dev->open_count = 0;
400 
401 unlock_exit:
402 	up(&dev->sem);
403 
404 exit:
405 	return retval;
406 }
407 
408 /**
409  *	ld_usb_poll
410  */
411 static unsigned int ld_usb_poll(struct file *file, poll_table *wait)
412 {
413 	struct ld_usb *dev;
414 	unsigned int mask = 0;
415 
416 	dev = file->private_data;
417 
418 	poll_wait(file, &dev->read_wait, wait);
419 	poll_wait(file, &dev->write_wait, wait);
420 
421 	if (dev->ring_head != dev->ring_tail)
422 		mask |= POLLIN | POLLRDNORM;
423 	if (!dev->interrupt_out_busy)
424 		mask |= POLLOUT | POLLWRNORM;
425 
426 	return mask;
427 }
428 
429 /**
430  *	ld_usb_read
431  */
432 static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
433 			   loff_t *ppos)
434 {
435 	struct ld_usb *dev;
436 	size_t *actual_buffer;
437 	size_t bytes_to_read;
438 	int retval = 0;
439 
440 	dev = file->private_data;
441 
442 	/* verify that we actually have some data to read */
443 	if (count == 0)
444 		goto exit;
445 
446 	/* lock this object */
447 	if (down_interruptible(&dev->sem)) {
448 		retval = -ERESTARTSYS;
449 		goto exit;
450 	}
451 
452 	/* verify that the device wasn't unplugged */
453 	if (dev->intf == NULL) {
454 		retval = -ENODEV;
455 		err("No device or device unplugged %d\n", retval);
456 		goto unlock_exit;
457 	}
458 
459 	/* wait for data */
460 	if (dev->ring_head == dev->ring_tail) {
461 		if (file->f_flags & O_NONBLOCK) {
462 			retval = -EAGAIN;
463 			goto unlock_exit;
464 		}
465 		retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
466 		if (retval < 0)
467 			goto unlock_exit;
468 	}
469 
470 	/* actual_buffer contains actual_length + interrupt_in_buffer */
471 	actual_buffer = (size_t*)(dev->ring_buffer + dev->ring_tail*(sizeof(size_t)+dev->interrupt_in_endpoint_size));
472 	bytes_to_read = min(count, *actual_buffer);
473 	if (bytes_to_read < *actual_buffer)
474 		dev_warn(&dev->intf->dev, "Read buffer overflow, %zd bytes dropped\n",
475 			 *actual_buffer-bytes_to_read);
476 
477 	/* copy one interrupt_in_buffer from ring_buffer into userspace */
478 	if (copy_to_user(buffer, actual_buffer+1, bytes_to_read)) {
479 		retval = -EFAULT;
480 		goto unlock_exit;
481 	}
482 	dev->ring_tail = (dev->ring_tail+1) % ring_buffer_size;
483 
484 	retval = bytes_to_read;
485 
486 unlock_exit:
487 	/* unlock the device */
488 	up(&dev->sem);
489 
490 exit:
491 	return retval;
492 }
493 
494 /**
495  *	ld_usb_write
496  */
497 static ssize_t ld_usb_write(struct file *file, const char __user *buffer,
498 			    size_t count, loff_t *ppos)
499 {
500 	struct ld_usb *dev;
501 	size_t bytes_to_write;
502 	int retval = 0;
503 
504 	dev = file->private_data;
505 
506 	/* verify that we actually have some data to write */
507 	if (count == 0)
508 		goto exit;
509 
510 	/* lock this object */
511 	if (down_interruptible(&dev->sem)) {
512 		retval = -ERESTARTSYS;
513 		goto exit;
514 	}
515 
516 	/* verify that the device wasn't unplugged */
517 	if (dev->intf == NULL) {
518 		retval = -ENODEV;
519 		err("No device or device unplugged %d\n", retval);
520 		goto unlock_exit;
521 	}
522 
523 	/* wait until previous transfer is finished */
524 	if (dev->interrupt_out_busy) {
525 		if (file->f_flags & O_NONBLOCK) {
526 			retval = -EAGAIN;
527 			goto unlock_exit;
528 		}
529 		retval = wait_event_interruptible(dev->write_wait, !dev->interrupt_out_busy);
530 		if (retval < 0) {
531 			goto unlock_exit;
532 		}
533 	}
534 
535 	/* write the data into interrupt_out_buffer from userspace */
536 	bytes_to_write = min(count, write_buffer_size*dev->interrupt_out_endpoint_size);
537 	if (bytes_to_write < count)
538 		dev_warn(&dev->intf->dev, "Write buffer overflow, %zd bytes dropped\n",count-bytes_to_write);
539 	dbg_info(&dev->intf->dev, "%s: count = %zd, bytes_to_write = %zd\n", __FUNCTION__, count, bytes_to_write);
540 
541 	if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
542 		retval = -EFAULT;
543 		goto unlock_exit;
544 	}
545 
546 	if (dev->interrupt_out_endpoint == NULL) {
547 		/* try HID_REQ_SET_REPORT=9 on control_endpoint instead of interrupt_out_endpoint */
548 		retval = usb_control_msg(interface_to_usbdev(dev->intf),
549 					 usb_sndctrlpipe(interface_to_usbdev(dev->intf), 0),
550 					 9,
551 					 USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
552 					 1 << 8, 0,
553 					 dev->interrupt_out_buffer,
554 					 bytes_to_write,
555 					 USB_CTRL_SET_TIMEOUT * HZ);
556 		if (retval < 0)
557 			err("Couldn't submit HID_REQ_SET_REPORT %d\n", retval);
558 		goto unlock_exit;
559 	}
560 
561 	/* send off the urb */
562 	usb_fill_int_urb(dev->interrupt_out_urb,
563 			 interface_to_usbdev(dev->intf),
564 			 usb_sndintpipe(interface_to_usbdev(dev->intf),
565 					dev->interrupt_out_endpoint->bEndpointAddress),
566 			 dev->interrupt_out_buffer,
567 			 bytes_to_write,
568 			 ld_usb_interrupt_out_callback,
569 			 dev,
570 			 dev->interrupt_out_interval);
571 
572 	dev->interrupt_out_busy = 1;
573 	wmb();
574 
575 	retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
576 	if (retval) {
577 		dev->interrupt_out_busy = 0;
578 		err("Couldn't submit interrupt_out_urb %d\n", retval);
579 		goto unlock_exit;
580 	}
581 	retval = bytes_to_write;
582 
583 unlock_exit:
584 	/* unlock the device */
585 	up(&dev->sem);
586 
587 exit:
588 	return retval;
589 }
590 
591 /* file operations needed when we register this driver */
592 static struct file_operations ld_usb_fops = {
593 	.owner =	THIS_MODULE,
594 	.read  =	ld_usb_read,
595 	.write =	ld_usb_write,
596 	.open =		ld_usb_open,
597 	.release =	ld_usb_release,
598 	.poll =		ld_usb_poll,
599 };
600 
601 /*
602  * usb class driver info in order to get a minor number from the usb core,
603  * and to have the device registered with the driver core
604  */
605 static struct usb_class_driver ld_usb_class = {
606 	.name =		"ldusb%d",
607 	.fops =		&ld_usb_fops,
608 	.minor_base =	USB_LD_MINOR_BASE,
609 };
610 
611 /**
612  *	ld_usb_probe
613  *
614  *	Called by the usb core when a new device is connected that it thinks
615  *	this driver might be interested in.
616  */
617 static int ld_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
618 {
619 	struct usb_device *udev = interface_to_usbdev(intf);
620 	struct ld_usb *dev = NULL;
621 	struct usb_host_interface *iface_desc;
622 	struct usb_endpoint_descriptor *endpoint;
623 	char *buffer;
624 	int i;
625 	int retval = -ENOMEM;
626 
627 	/* allocate memory for our device state and intialize it */
628 
629 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
630 	if (dev == NULL) {
631 		dev_err(&intf->dev, "Out of memory\n");
632 		goto exit;
633 	}
634 	init_MUTEX(&dev->sem);
635 	dev->intf = intf;
636 	init_waitqueue_head(&dev->read_wait);
637 	init_waitqueue_head(&dev->write_wait);
638 
639 	/* workaround for early firmware versions on fast computers */
640 	if ((le16_to_cpu(udev->descriptor.idVendor) == USB_VENDOR_ID_LD) &&
641 	    ((le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_CASSY) ||
642 	     (le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_COM3LAB)) &&
643 	    (le16_to_cpu(udev->descriptor.bcdDevice) <= 0x103)) {
644 		buffer = kmalloc(256, GFP_KERNEL);
645 		if (buffer == NULL) {
646 			dev_err(&intf->dev, "Couldn't allocate string buffer\n");
647 			goto error;
648 		}
649 		/* usb_string makes SETUP+STALL to leave always ControlReadLoop */
650 		usb_string(udev, 255, buffer, 256);
651 		kfree(buffer);
652 	}
653 
654 	iface_desc = intf->cur_altsetting;
655 
656 	/* set up the endpoint information */
657 	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
658 		endpoint = &iface_desc->endpoint[i].desc;
659 
660 		if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_IN) &&
661 		    ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT)) {
662 			dev->interrupt_in_endpoint = endpoint;
663 		}
664 
665 		if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT) &&
666 		    ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT)) {
667 			dev->interrupt_out_endpoint = endpoint;
668 		}
669 	}
670 	if (dev->interrupt_in_endpoint == NULL) {
671 		dev_err(&intf->dev, "Interrupt in endpoint not found\n");
672 		goto error;
673 	}
674 	if (dev->interrupt_out_endpoint == NULL)
675 		dev_warn(&intf->dev, "Interrupt out endpoint not found (using control endpoint instead)\n");
676 
677 	dev->interrupt_in_endpoint_size = le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize);
678 	dev->ring_buffer = kmalloc(ring_buffer_size*(sizeof(size_t)+dev->interrupt_in_endpoint_size), GFP_KERNEL);
679 	if (!dev->ring_buffer) {
680 		dev_err(&intf->dev, "Couldn't allocate ring_buffer\n");
681 		goto error;
682 	}
683 	dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
684 	if (!dev->interrupt_in_buffer) {
685 		dev_err(&intf->dev, "Couldn't allocate interrupt_in_buffer\n");
686 		goto error;
687 	}
688 	dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
689 	if (!dev->interrupt_in_urb) {
690 		dev_err(&intf->dev, "Couldn't allocate interrupt_in_urb\n");
691 		goto error;
692 	}
693 	dev->interrupt_out_endpoint_size = dev->interrupt_out_endpoint ? le16_to_cpu(dev->interrupt_out_endpoint->wMaxPacketSize) :
694 									 udev->descriptor.bMaxPacketSize0;
695 	dev->interrupt_out_buffer = kmalloc(write_buffer_size*dev->interrupt_out_endpoint_size, GFP_KERNEL);
696 	if (!dev->interrupt_out_buffer) {
697 		dev_err(&intf->dev, "Couldn't allocate interrupt_out_buffer\n");
698 		goto error;
699 	}
700 	dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
701 	if (!dev->interrupt_out_urb) {
702 		dev_err(&intf->dev, "Couldn't allocate interrupt_out_urb\n");
703 		goto error;
704 	}
705 	dev->interrupt_in_interval = min_interrupt_in_interval > dev->interrupt_in_endpoint->bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
706 	if (dev->interrupt_out_endpoint)
707 		dev->interrupt_out_interval = min_interrupt_out_interval > dev->interrupt_out_endpoint->bInterval ? min_interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
708 
709 	/* we can register the device now, as it is ready */
710 	usb_set_intfdata(intf, dev);
711 
712 	retval = usb_register_dev(intf, &ld_usb_class);
713 	if (retval) {
714 		/* something prevented us from registering this driver */
715 		dev_err(&intf->dev, "Not able to get a minor for this device.\n");
716 		usb_set_intfdata(intf, NULL);
717 		goto error;
718 	}
719 
720 	/* let the user know what node this device is now attached to */
721 	dev_info(&intf->dev, "LD USB Device #%d now attached to major %d minor %d\n",
722 		(intf->minor - USB_LD_MINOR_BASE), USB_MAJOR, intf->minor);
723 
724 exit:
725 	return retval;
726 
727 error:
728 	ld_usb_delete(dev);
729 
730 	return retval;
731 }
732 
733 /**
734  *	ld_usb_disconnect
735  *
736  *	Called by the usb core when the device is removed from the system.
737  */
738 static void ld_usb_disconnect(struct usb_interface *intf)
739 {
740 	struct ld_usb *dev;
741 	int minor;
742 
743 	mutex_lock(&disconnect_mutex);
744 
745 	dev = usb_get_intfdata(intf);
746 	usb_set_intfdata(intf, NULL);
747 
748 	down(&dev->sem);
749 
750 	minor = intf->minor;
751 
752 	/* give back our minor */
753 	usb_deregister_dev(intf, &ld_usb_class);
754 
755 	/* if the device is not opened, then we clean up right now */
756 	if (!dev->open_count) {
757 		up(&dev->sem);
758 		ld_usb_delete(dev);
759 	} else {
760 		dev->intf = NULL;
761 		up(&dev->sem);
762 	}
763 
764 	mutex_unlock(&disconnect_mutex);
765 
766 	dev_info(&intf->dev, "LD USB Device #%d now disconnected\n",
767 		 (minor - USB_LD_MINOR_BASE));
768 }
769 
770 /* usb specific object needed to register this driver with the usb subsystem */
771 static struct usb_driver ld_usb_driver = {
772 	.name =		"ldusb",
773 	.probe =	ld_usb_probe,
774 	.disconnect =	ld_usb_disconnect,
775 	.id_table =	ld_usb_table,
776 };
777 
778 /**
779  *	ld_usb_init
780  */
781 static int __init ld_usb_init(void)
782 {
783 	int retval;
784 
785 	/* register this driver with the USB subsystem */
786 	retval = usb_register(&ld_usb_driver);
787 	if (retval)
788 		err("usb_register failed for the "__FILE__" driver. Error number %d\n", retval);
789 
790 	return retval;
791 }
792 
793 /**
794  *	ld_usb_exit
795  */
796 static void __exit ld_usb_exit(void)
797 {
798 	/* deregister this driver with the USB subsystem */
799 	usb_deregister(&ld_usb_driver);
800 }
801 
802 module_init(ld_usb_init);
803 module_exit(ld_usb_exit);
804 
805