xref: /linux/drivers/usb/misc/adutux.c (revision 8b4a40809e5330c9da5d20107d693d92d73b31dc)
1 /*
2  * adutux - driver for ADU devices from Ontrak Control Systems
3  * This is an experimental driver. Use at your own risk.
4  * This driver is not supported by Ontrak Control Systems.
5  *
6  * Copyright (c) 2003 John Homppi (SCO, leave this notice here)
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License as
10  * published by the Free Software Foundation; either version 2 of
11  * the License, or (at your option) any later version.
12  *
13  * derived from the Lego USB Tower driver 0.56:
14  * Copyright (c) 2003 David Glance <davidgsf@sourceforge.net>
15  *               2001 Juergen Stuber <stuber@loria.fr>
16  * that was derived from USB Skeleton driver - 0.5
17  * Copyright (c) 2001 Greg Kroah-Hartman (greg@kroah.com)
18  *
19  */
20 
21 #include <linux/kernel.h>
22 #include <linux/errno.h>
23 #include <linux/init.h>
24 #include <linux/slab.h>
25 #include <linux/module.h>
26 #include <linux/usb.h>
27 #include <asm/uaccess.h>
28 
29 #ifdef CONFIG_USB_DEBUG
30 static int debug = 5;
31 #else
32 static int debug = 1;
33 #endif
34 
35 /* Use our own dbg macro */
36 #undef dbg
37 #define dbg(lvl, format, arg...) 					\
38 do { 									\
39 	if (debug >= lvl)						\
40 		printk(KERN_DEBUG __FILE__ " : " format " \n", ## arg);	\
41 } while (0)
42 
43 
44 /* Version Information */
45 #define DRIVER_VERSION "v0.0.13"
46 #define DRIVER_AUTHOR "John Homppi"
47 #define DRIVER_DESC "adutux (see www.ontrak.net)"
48 
49 /* Module parameters */
50 module_param(debug, int, S_IRUGO | S_IWUSR);
51 MODULE_PARM_DESC(debug, "Debug enabled or not");
52 
53 /* Define these values to match your device */
54 #define ADU_VENDOR_ID 0x0a07
55 #define ADU_PRODUCT_ID 0x0064
56 
57 /* table of devices that work with this driver */
58 static struct usb_device_id device_table [] = {
59 	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID) },		/* ADU100 */
60 	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+20) }, 	/* ADU120 */
61 	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+30) }, 	/* ADU130 */
62 	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+100) },	/* ADU200 */
63 	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+108) },	/* ADU208 */
64 	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+118) },	/* ADU218 */
65 	{ }/* Terminating entry */
66 };
67 
68 MODULE_DEVICE_TABLE(usb, device_table);
69 
70 #ifdef CONFIG_USB_DYNAMIC_MINORS
71 #define ADU_MINOR_BASE	0
72 #else
73 #define ADU_MINOR_BASE	67
74 #endif
75 
76 /* we can have up to this number of device plugged in at once */
77 #define MAX_DEVICES	16
78 
79 #define COMMAND_TIMEOUT	(2*HZ)	/* 60 second timeout for a command */
80 
81 /* Structure to hold all of our device specific stuff */
82 struct adu_device {
83 	struct semaphore	sem; /* locks this structure */
84 	struct usb_device*	udev; /* save off the usb device pointer */
85 	struct usb_interface*	interface;
86 	unsigned char		minor; /* the starting minor number for this device */
87 	char			serial_number[8];
88 
89 	int			open_count; /* number of times this port has been opened */
90 
91 	char*			read_buffer_primary;
92 	int			read_buffer_length;
93 	char*			read_buffer_secondary;
94 	int			secondary_head;
95 	int			secondary_tail;
96 	spinlock_t		buflock;
97 
98 	wait_queue_head_t	read_wait;
99 	wait_queue_head_t	write_wait;
100 
101 	char*			interrupt_in_buffer;
102 	struct usb_endpoint_descriptor* interrupt_in_endpoint;
103 	struct urb*		interrupt_in_urb;
104 	int			read_urb_finished;
105 
106 	char*			interrupt_out_buffer;
107 	struct usb_endpoint_descriptor* interrupt_out_endpoint;
108 	struct urb*		interrupt_out_urb;
109 };
110 
111 static struct usb_driver adu_driver;
112 
113 static void adu_debug_data(int level, const char *function, int size,
114 			   const unsigned char *data)
115 {
116 	int i;
117 
118 	if (debug < level)
119 		return;
120 
121 	printk(KERN_DEBUG __FILE__": %s - length = %d, data = ",
122 	       function, size);
123 	for (i = 0; i < size; ++i)
124 		printk("%.2x ", data[i]);
125 	printk("\n");
126 }
127 
128 /**
129  * adu_abort_transfers
130  *      aborts transfers and frees associated data structures
131  */
132 static void adu_abort_transfers(struct adu_device *dev)
133 {
134 	dbg(2," %s : enter", __FUNCTION__);
135 
136 	if (dev == NULL) {
137 		dbg(1," %s : dev is null", __FUNCTION__);
138 		goto exit;
139 	}
140 
141 	if (dev->udev == NULL) {
142 		dbg(1," %s : udev is null", __FUNCTION__);
143 		goto exit;
144 	}
145 
146 	dbg(2," %s : udev state %d", __FUNCTION__, dev->udev->state);
147 	if (dev->udev->state == USB_STATE_NOTATTACHED) {
148 		dbg(1," %s : udev is not attached", __FUNCTION__);
149 		goto exit;
150 	}
151 
152 	/* shutdown transfer */
153 	usb_unlink_urb(dev->interrupt_in_urb);
154 	usb_unlink_urb(dev->interrupt_out_urb);
155 
156 exit:
157 	dbg(2," %s : leave", __FUNCTION__);
158 }
159 
160 static void adu_delete(struct adu_device *dev)
161 {
162 	dbg(2, "%s enter", __FUNCTION__);
163 
164 	adu_abort_transfers(dev);
165 
166 	/* free data structures */
167 	usb_free_urb(dev->interrupt_in_urb);
168 	usb_free_urb(dev->interrupt_out_urb);
169 	kfree(dev->read_buffer_primary);
170 	kfree(dev->read_buffer_secondary);
171 	kfree(dev->interrupt_in_buffer);
172 	kfree(dev->interrupt_out_buffer);
173 	kfree(dev);
174 
175 	dbg(2, "%s : leave", __FUNCTION__);
176 }
177 
178 static void adu_interrupt_in_callback(struct urb *urb)
179 {
180 	struct adu_device *dev = urb->context;
181 
182 	dbg(4," %s : enter, status %d", __FUNCTION__, urb->status);
183 	adu_debug_data(5, __FUNCTION__, urb->actual_length,
184 		       urb->transfer_buffer);
185 
186 	spin_lock(&dev->buflock);
187 
188 	if (urb->status != 0) {
189 		if ((urb->status != -ENOENT) && (urb->status != -ECONNRESET)) {
190 			dbg(1," %s : nonzero status received: %d",
191 			    __FUNCTION__, urb->status);
192 		}
193 		goto exit;
194 	}
195 
196 	if (urb->actual_length > 0 && dev->interrupt_in_buffer[0] != 0x00) {
197 		if (dev->read_buffer_length <
198 		    (4 * le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize)) -
199 		     (urb->actual_length)) {
200 			memcpy (dev->read_buffer_primary +
201 				dev->read_buffer_length,
202 				dev->interrupt_in_buffer, urb->actual_length);
203 
204 			dev->read_buffer_length += urb->actual_length;
205 			dbg(2," %s reading  %d ", __FUNCTION__,
206 			    urb->actual_length);
207 		} else {
208 			dbg(1," %s : read_buffer overflow", __FUNCTION__);
209 		}
210 	}
211 
212 exit:
213 	dev->read_urb_finished = 1;
214 	spin_unlock(&dev->buflock);
215 	/* always wake up so we recover from errors */
216 	wake_up_interruptible(&dev->read_wait);
217 	adu_debug_data(5, __FUNCTION__, urb->actual_length,
218 		       urb->transfer_buffer);
219 	dbg(4," %s : leave, status %d", __FUNCTION__, urb->status);
220 }
221 
222 static void adu_interrupt_out_callback(struct urb *urb)
223 {
224 	struct adu_device *dev = urb->context;
225 
226 	dbg(4," %s : enter, status %d", __FUNCTION__, urb->status);
227 	adu_debug_data(5,__FUNCTION__, urb->actual_length, urb->transfer_buffer);
228 
229 	if (urb->status != 0) {
230 		if ((urb->status != -ENOENT) &&
231 		    (urb->status != -ECONNRESET)) {
232 			dbg(1, " %s :nonzero status received: %d",
233 			    __FUNCTION__, urb->status);
234 		}
235 		goto exit;
236 	}
237 
238 	wake_up_interruptible(&dev->write_wait);
239 exit:
240 
241 	adu_debug_data(5, __FUNCTION__, urb->actual_length,
242 		       urb->transfer_buffer);
243 	dbg(4," %s : leave, status %d", __FUNCTION__, urb->status);
244 }
245 
246 static int adu_open(struct inode *inode, struct file *file)
247 {
248 	struct adu_device *dev = NULL;
249 	struct usb_interface *interface;
250 	int subminor;
251 	int retval = 0;
252 
253 	dbg(2,"%s : enter", __FUNCTION__);
254 
255 	subminor = iminor(inode);
256 
257 	interface = usb_find_interface(&adu_driver, subminor);
258 	if (!interface) {
259 		err("%s - error, can't find device for minor %d",
260 		    __FUNCTION__, subminor);
261 		retval = -ENODEV;
262 		goto exit_no_device;
263 	}
264 
265 	dev = usb_get_intfdata(interface);
266 	if (!dev) {
267 		retval = -ENODEV;
268 		goto exit_no_device;
269 	}
270 
271 	/* lock this device */
272 	if ((retval = down_interruptible(&dev->sem))) {
273 		dbg(2, "%s : sem down failed", __FUNCTION__);
274 		goto exit_no_device;
275 	}
276 
277 	/* increment our usage count for the device */
278 	++dev->open_count;
279 	dbg(2,"%s : open count %d", __FUNCTION__, dev->open_count);
280 
281 	/* save device in the file's private structure */
282 	file->private_data = dev;
283 
284 	if (dev->open_count == 1) {
285 		/* initialize in direction */
286 		dev->read_buffer_length = 0;
287 
288 		/* fixup first read by having urb waiting for it */
289 		usb_fill_int_urb(dev->interrupt_in_urb,dev->udev,
290 				 usb_rcvintpipe(dev->udev,
291 				 		dev->interrupt_in_endpoint->bEndpointAddress),
292 				 dev->interrupt_in_buffer,
293 				 le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
294 				 adu_interrupt_in_callback, dev,
295 				 dev->interrupt_in_endpoint->bInterval);
296 		/* dev->interrupt_in_urb->transfer_flags |= URB_ASYNC_UNLINK; */
297 		dev->read_urb_finished = 0;
298 		retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
299 		if (retval)
300 			--dev->open_count;
301 	}
302 	up(&dev->sem);
303 
304 exit_no_device:
305 	dbg(2,"%s : leave, return value %d ", __FUNCTION__, retval);
306 
307 	return retval;
308 }
309 
310 static int adu_release_internal(struct adu_device *dev)
311 {
312 	int retval = 0;
313 
314 	dbg(2," %s : enter", __FUNCTION__);
315 
316 	/* decrement our usage count for the device */
317 	--dev->open_count;
318 	dbg(2," %s : open count %d", __FUNCTION__, dev->open_count);
319 	if (dev->open_count <= 0) {
320 		adu_abort_transfers(dev);
321 		dev->open_count = 0;
322 	}
323 
324 	dbg(2," %s : leave", __FUNCTION__);
325 	return retval;
326 }
327 
328 static int adu_release(struct inode *inode, struct file *file)
329 {
330 	struct adu_device *dev = NULL;
331 	int retval = 0;
332 
333 	dbg(2," %s : enter", __FUNCTION__);
334 
335 	if (file == NULL) {
336  		dbg(1," %s : file is NULL", __FUNCTION__);
337 		retval = -ENODEV;
338 		goto exit;
339 	}
340 
341 	dev = file->private_data;
342 
343 	if (dev == NULL) {
344  		dbg(1," %s : object is NULL", __FUNCTION__);
345 		retval = -ENODEV;
346 		goto exit;
347 	}
348 
349 	/* lock our device */
350 	down(&dev->sem); /* not interruptible */
351 
352 	if (dev->open_count <= 0) {
353 		dbg(1," %s : device not opened", __FUNCTION__);
354 		retval = -ENODEV;
355 		goto exit;
356 	}
357 
358 	if (dev->udev == NULL) {
359 		/* the device was unplugged before the file was released */
360 		up(&dev->sem);
361 		adu_delete(dev);
362 		dev = NULL;
363 	} else {
364 		/* do the work */
365 		retval = adu_release_internal(dev);
366 	}
367 
368 exit:
369 	if (dev)
370 		up(&dev->sem);
371 	dbg(2," %s : leave, return value %d", __FUNCTION__, retval);
372 	return retval;
373 }
374 
375 static ssize_t adu_read(struct file *file, __user char *buffer, size_t count,
376 			loff_t *ppos)
377 {
378 	struct adu_device *dev;
379 	size_t bytes_read = 0;
380 	size_t bytes_to_read = count;
381 	int i;
382 	int retval = 0;
383 	int timeout = 0;
384 	int should_submit = 0;
385 	unsigned long flags;
386 	DECLARE_WAITQUEUE(wait, current);
387 
388 	dbg(2," %s : enter, count = %Zd, file=%p", __FUNCTION__, count, file);
389 
390 	dev = file->private_data;
391 	dbg(2," %s : dev=%p", __FUNCTION__, dev);
392 	/* lock this object */
393 	if (down_interruptible(&dev->sem))
394 		return -ERESTARTSYS;
395 
396 	/* verify that the device wasn't unplugged */
397 	if (dev->udev == NULL || dev->minor == 0) {
398 		retval = -ENODEV;
399 		err("No device or device unplugged %d", retval);
400 		goto exit;
401 	}
402 
403 	/* verify that some data was requested */
404 	if (count == 0) {
405 		dbg(1," %s : read request of 0 bytes", __FUNCTION__);
406 		goto exit;
407 	}
408 
409 	timeout = COMMAND_TIMEOUT;
410 	dbg(2," %s : about to start looping", __FUNCTION__);
411 	while (bytes_to_read) {
412 		int data_in_secondary = dev->secondary_tail - dev->secondary_head;
413 		dbg(2," %s : while, data_in_secondary=%d, status=%d",
414 		    __FUNCTION__, data_in_secondary,
415 		    dev->interrupt_in_urb->status);
416 
417 		if (data_in_secondary) {
418 			/* drain secondary buffer */
419 			int amount = bytes_to_read < data_in_secondary ? bytes_to_read : data_in_secondary;
420 			i = copy_to_user(buffer, dev->read_buffer_secondary+dev->secondary_head, amount);
421 			if (i < 0) {
422 				retval = -EFAULT;
423 				goto exit;
424 			}
425 			dev->secondary_head += (amount - i);
426 			bytes_read += (amount - i);
427 			bytes_to_read -= (amount - i);
428 			if (i) {
429 				retval = bytes_read ? bytes_read : -EFAULT;
430 				goto exit;
431 			}
432 		} else {
433 			/* we check the primary buffer */
434 			spin_lock_irqsave (&dev->buflock, flags);
435 			if (dev->read_buffer_length) {
436 				/* we secure access to the primary */
437 				char *tmp;
438 				dbg(2," %s : swap, read_buffer_length = %d",
439 				    __FUNCTION__, dev->read_buffer_length);
440 				tmp = dev->read_buffer_secondary;
441 				dev->read_buffer_secondary = dev->read_buffer_primary;
442 				dev->read_buffer_primary = tmp;
443 				dev->secondary_head = 0;
444 				dev->secondary_tail = dev->read_buffer_length;
445 				dev->read_buffer_length = 0;
446 				spin_unlock_irqrestore(&dev->buflock, flags);
447 				/* we have a free buffer so use it */
448 				should_submit = 1;
449 			} else {
450 				/* even the primary was empty - we may need to do IO */
451 				if (dev->interrupt_in_urb->status == -EINPROGRESS) {
452 					/* somebody is doing IO */
453 					spin_unlock_irqrestore(&dev->buflock, flags);
454 					dbg(2," %s : submitted already", __FUNCTION__);
455 				} else {
456 					/* we must initiate input */
457 					dbg(2," %s : initiate input", __FUNCTION__);
458 					dev->read_urb_finished = 0;
459 
460 					usb_fill_int_urb(dev->interrupt_in_urb,dev->udev,
461 							 usb_rcvintpipe(dev->udev,
462 							 		dev->interrupt_in_endpoint->bEndpointAddress),
463 							 dev->interrupt_in_buffer,
464 							 le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
465 							 adu_interrupt_in_callback,
466 							 dev,
467 							 dev->interrupt_in_endpoint->bInterval);
468 					retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
469 					if (!retval) {
470 						spin_unlock_irqrestore(&dev->buflock, flags);
471 						dbg(2," %s : submitted OK", __FUNCTION__);
472 					} else {
473 						if (retval == -ENOMEM) {
474 							retval = bytes_read ? bytes_read : -ENOMEM;
475 						}
476 						spin_unlock_irqrestore(&dev->buflock, flags);
477 						dbg(2," %s : submit failed", __FUNCTION__);
478 						goto exit;
479 					}
480 				}
481 
482 				/* we wait for I/O to complete */
483 				set_current_state(TASK_INTERRUPTIBLE);
484 				add_wait_queue(&dev->read_wait, &wait);
485 				if (!dev->read_urb_finished)
486 					timeout = schedule_timeout(COMMAND_TIMEOUT);
487 				else
488 					set_current_state(TASK_RUNNING);
489 				remove_wait_queue(&dev->read_wait, &wait);
490 
491 				if (timeout <= 0) {
492 					dbg(2," %s : timeout", __FUNCTION__);
493 					retval = bytes_read ? bytes_read : -ETIMEDOUT;
494 					goto exit;
495 				}
496 
497 				if (signal_pending(current)) {
498 					dbg(2," %s : signal pending", __FUNCTION__);
499 					retval = bytes_read ? bytes_read : -EINTR;
500 					goto exit;
501 				}
502 			}
503 		}
504 	}
505 
506 	retval = bytes_read;
507 	/* if the primary buffer is empty then use it */
508 	if (should_submit && !dev->interrupt_in_urb->status==-EINPROGRESS) {
509 		usb_fill_int_urb(dev->interrupt_in_urb,dev->udev,
510 				 usb_rcvintpipe(dev->udev,
511 				 		dev->interrupt_in_endpoint->bEndpointAddress),
512 						dev->interrupt_in_buffer,
513 						le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
514 						adu_interrupt_in_callback,
515 						dev,
516 						dev->interrupt_in_endpoint->bInterval);
517 		/* dev->interrupt_in_urb->transfer_flags |= URB_ASYNC_UNLINK; */
518 		dev->read_urb_finished = 0;
519 		usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
520 		/* we ignore failure */
521 	}
522 
523 exit:
524 	/* unlock the device */
525 	up(&dev->sem);
526 
527 	dbg(2," %s : leave, return value %d", __FUNCTION__, retval);
528 	return retval;
529 }
530 
531 static ssize_t adu_write(struct file *file, const __user char *buffer,
532 			 size_t count, loff_t *ppos)
533 {
534 	struct adu_device *dev;
535 	size_t bytes_written = 0;
536 	size_t bytes_to_write;
537 	size_t buffer_size;
538 	int retval;
539 	int timeout = 0;
540 
541 	dbg(2," %s : enter, count = %Zd", __FUNCTION__, count);
542 
543 	dev = file->private_data;
544 
545 	/* lock this object */
546 	retval = down_interruptible(&dev->sem);
547 	if (retval)
548 		goto exit_nolock;
549 
550 	/* verify that the device wasn't unplugged */
551 	if (dev->udev == NULL || dev->minor == 0) {
552 		retval = -ENODEV;
553 		err("No device or device unplugged %d", retval);
554 		goto exit;
555 	}
556 
557 	/* verify that we actually have some data to write */
558 	if (count == 0) {
559 		dbg(1," %s : write request of 0 bytes", __FUNCTION__);
560 		goto exit;
561 	}
562 
563 
564 	while (count > 0) {
565 		if (dev->interrupt_out_urb->status == -EINPROGRESS) {
566 			timeout = COMMAND_TIMEOUT;
567 
568 			while (timeout > 0) {
569 				if (signal_pending(current)) {
570 				dbg(1," %s : interrupted", __FUNCTION__);
571 				retval = -EINTR;
572 				goto exit;
573 			}
574 			up(&dev->sem);
575 			timeout = interruptible_sleep_on_timeout(&dev->write_wait, timeout);
576 			retval = down_interruptible(&dev->sem);
577 			if (retval) {
578 				retval = bytes_written ? bytes_written : retval;
579 				goto exit_nolock;
580 			}
581 			if (timeout > 0) {
582 				break;
583 			}
584 			dbg(1," %s : interrupted timeout: %d", __FUNCTION__, timeout);
585 		}
586 
587 
588 		dbg(1," %s : final timeout: %d", __FUNCTION__, timeout);
589 
590 		if (timeout == 0) {
591 			dbg(1, "%s - command timed out.", __FUNCTION__);
592 			retval = -ETIMEDOUT;
593 			goto exit;
594 		}
595 
596 		dbg(4," %s : in progress, count = %Zd", __FUNCTION__, count);
597 
598 		} else {
599 			dbg(4," %s : sending, count = %Zd", __FUNCTION__, count);
600 
601 			/* write the data into interrupt_out_buffer from userspace */
602 			buffer_size = le16_to_cpu(dev->interrupt_out_endpoint->wMaxPacketSize);
603 			bytes_to_write = count > buffer_size ? buffer_size : count;
604 			dbg(4," %s : buffer_size = %Zd, count = %Zd, bytes_to_write = %Zd",
605 			    __FUNCTION__, buffer_size, count, bytes_to_write);
606 
607 			if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write) != 0) {
608 				retval = -EFAULT;
609 				goto exit;
610 			}
611 
612 			/* send off the urb */
613 			usb_fill_int_urb(
614 				dev->interrupt_out_urb,
615 				dev->udev,
616 				usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
617 				dev->interrupt_out_buffer,
618 				bytes_to_write,
619 				adu_interrupt_out_callback,
620 				dev,
621 				dev->interrupt_in_endpoint->bInterval);
622 			/* dev->interrupt_in_urb->transfer_flags |= URB_ASYNC_UNLINK; */
623 			dev->interrupt_out_urb->actual_length = bytes_to_write;
624 			retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
625 			if (retval < 0) {
626 				err("Couldn't submit interrupt_out_urb %d", retval);
627 				goto exit;
628 			}
629 
630 			buffer += bytes_to_write;
631 			count -= bytes_to_write;
632 
633 			bytes_written += bytes_to_write;
634 		}
635 	}
636 
637 	retval = bytes_written;
638 
639 exit:
640 	/* unlock the device */
641 	up(&dev->sem);
642 exit_nolock:
643 
644 	dbg(2," %s : leave, return value %d", __FUNCTION__, retval);
645 
646 	return retval;
647 }
648 
649 /* file operations needed when we register this driver */
650 static const struct file_operations adu_fops = {
651 	.owner = THIS_MODULE,
652 	.read  = adu_read,
653 	.write = adu_write,
654 	.open = adu_open,
655 	.release = adu_release,
656 };
657 
658 /*
659  * usb class driver info in order to get a minor number from the usb core,
660  * and to have the device registered with devfs and the driver core
661  */
662 static struct usb_class_driver adu_class = {
663 	.name = "usb/adutux%d",
664 	.fops = &adu_fops,
665 	.minor_base = ADU_MINOR_BASE,
666 };
667 
668 /**
669  * adu_probe
670  *
671  * Called by the usb core when a new device is connected that it thinks
672  * this driver might be interested in.
673  */
674 static int adu_probe(struct usb_interface *interface,
675 		     const struct usb_device_id *id)
676 {
677 	struct usb_device *udev = interface_to_usbdev(interface);
678 	struct adu_device *dev = NULL;
679 	struct usb_host_interface *iface_desc;
680 	struct usb_endpoint_descriptor *endpoint;
681 	int retval = -ENODEV;
682 	int in_end_size;
683 	int out_end_size;
684 	int i;
685 
686 	dbg(2," %s : enter", __FUNCTION__);
687 
688 	if (udev == NULL) {
689 		dev_err(&interface->dev, "udev is NULL.\n");
690 		goto exit;
691 	}
692 
693 	/* allocate memory for our device state and intialize it */
694 	dev = kzalloc(sizeof(struct adu_device), GFP_KERNEL);
695 	if (dev == NULL) {
696 		dev_err(&interface->dev, "Out of memory\n");
697 		retval = -ENOMEM;
698 		goto exit;
699 	}
700 
701 	init_MUTEX(&dev->sem);
702 	spin_lock_init(&dev->buflock);
703 	dev->udev = udev;
704 	init_waitqueue_head(&dev->read_wait);
705 	init_waitqueue_head(&dev->write_wait);
706 
707 	iface_desc = &interface->altsetting[0];
708 
709 	/* set up the endpoint information */
710 	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
711 		endpoint = &iface_desc->endpoint[i].desc;
712 
713 		if (usb_endpoint_is_int_in(endpoint))
714 			dev->interrupt_in_endpoint = endpoint;
715 
716 		if (usb_endpoint_is_int_out(endpoint))
717 			dev->interrupt_out_endpoint = endpoint;
718 	}
719 	if (dev->interrupt_in_endpoint == NULL) {
720 		dev_err(&interface->dev, "interrupt in endpoint not found\n");
721 		goto error;
722 	}
723 	if (dev->interrupt_out_endpoint == NULL) {
724 		dev_err(&interface->dev, "interrupt out endpoint not found\n");
725 		goto error;
726 	}
727 
728 	in_end_size = le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize);
729 	out_end_size = le16_to_cpu(dev->interrupt_out_endpoint->wMaxPacketSize);
730 
731 	dev->read_buffer_primary = kmalloc((4 * in_end_size), GFP_KERNEL);
732 	if (!dev->read_buffer_primary) {
733 		dev_err(&interface->dev, "Couldn't allocate read_buffer_primary\n");
734 		retval = -ENOMEM;
735 		goto error;
736 	}
737 
738 	/* debug code prime the buffer */
739 	memset(dev->read_buffer_primary, 'a', in_end_size);
740 	memset(dev->read_buffer_primary + in_end_size, 'b', in_end_size);
741 	memset(dev->read_buffer_primary + (2 * in_end_size), 'c', in_end_size);
742 	memset(dev->read_buffer_primary + (3 * in_end_size), 'd', in_end_size);
743 
744 	dev->read_buffer_secondary = kmalloc((4 * in_end_size), GFP_KERNEL);
745 	if (!dev->read_buffer_secondary) {
746 		dev_err(&interface->dev, "Couldn't allocate read_buffer_secondary\n");
747 		retval = -ENOMEM;
748 		goto error;
749 	}
750 
751 	/* debug code prime the buffer */
752 	memset(dev->read_buffer_secondary, 'e', in_end_size);
753 	memset(dev->read_buffer_secondary + in_end_size, 'f', in_end_size);
754 	memset(dev->read_buffer_secondary + (2 * in_end_size), 'g', in_end_size);
755 	memset(dev->read_buffer_secondary + (3 * in_end_size), 'h', in_end_size);
756 
757 	dev->interrupt_in_buffer = kmalloc(in_end_size, GFP_KERNEL);
758 	if (!dev->interrupt_in_buffer) {
759 		dev_err(&interface->dev, "Couldn't allocate interrupt_in_buffer\n");
760 		goto error;
761 	}
762 
763 	/* debug code prime the buffer */
764 	memset(dev->interrupt_in_buffer, 'i', in_end_size);
765 
766 	dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
767 	if (!dev->interrupt_in_urb) {
768 		dev_err(&interface->dev, "Couldn't allocate interrupt_in_urb\n");
769 		goto error;
770 	}
771 	dev->interrupt_out_buffer = kmalloc(out_end_size, GFP_KERNEL);
772 	if (!dev->interrupt_out_buffer) {
773 		dev_err(&interface->dev, "Couldn't allocate interrupt_out_buffer\n");
774 		goto error;
775 	}
776 	dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
777 	if (!dev->interrupt_out_urb) {
778 		dev_err(&interface->dev, "Couldn't allocate interrupt_out_urb\n");
779 		goto error;
780 	}
781 
782 	if (!usb_string(udev, udev->descriptor.iSerialNumber, dev->serial_number,
783 			sizeof(dev->serial_number))) {
784 		dev_err(&interface->dev, "Could not retrieve serial number\n");
785 		goto error;
786 	}
787 	dbg(2," %s : serial_number=%s", __FUNCTION__, dev->serial_number);
788 
789 	/* we can register the device now, as it is ready */
790 	usb_set_intfdata(interface, dev);
791 
792 	retval = usb_register_dev(interface, &adu_class);
793 
794 	if (retval) {
795 		/* something prevented us from registering this driver */
796 		dev_err(&interface->dev, "Not able to get a minor for this device.\n");
797 		usb_set_intfdata(interface, NULL);
798 		goto error;
799 	}
800 
801 	dev->minor = interface->minor;
802 
803 	/* let the user know what node this device is now attached to */
804 	dev_info(&interface->dev, "ADU%d %s now attached to /dev/usb/adutux%d",
805 		 udev->descriptor.idProduct, dev->serial_number,
806 		 (dev->minor - ADU_MINOR_BASE));
807 exit:
808 	dbg(2," %s : leave, return value %p (dev)", __FUNCTION__, dev);
809 
810 	return retval;
811 
812 error:
813 	adu_delete(dev);
814 	return retval;
815 }
816 
817 /**
818  * adu_disconnect
819  *
820  * Called by the usb core when the device is removed from the system.
821  */
822 static void adu_disconnect(struct usb_interface *interface)
823 {
824 	struct adu_device *dev;
825 	int minor;
826 
827 	dbg(2," %s : enter", __FUNCTION__);
828 
829 	dev = usb_get_intfdata(interface);
830 	usb_set_intfdata(interface, NULL);
831 
832 	minor = dev->minor;
833 
834 	/* give back our minor */
835 	usb_deregister_dev(interface, &adu_class);
836 	dev->minor = 0;
837 
838 	down(&dev->sem); /* not interruptible */
839 
840 	/* if the device is not opened, then we clean up right now */
841 	dbg(2," %s : open count %d", __FUNCTION__, dev->open_count);
842 	if (!dev->open_count) {
843 		up(&dev->sem);
844 		adu_delete(dev);
845 	} else {
846 		dev->udev = NULL;
847 		up(&dev->sem);
848 	}
849 
850 	dev_info(&interface->dev, "ADU device adutux%d now disconnected",
851 		 (minor - ADU_MINOR_BASE));
852 
853 	dbg(2," %s : leave", __FUNCTION__);
854 }
855 
856 /* usb specific object needed to register this driver with the usb subsystem */
857 static struct usb_driver adu_driver = {
858 	.name = "adutux",
859 	.probe = adu_probe,
860 	.disconnect = adu_disconnect,
861 	.id_table = device_table,
862 };
863 
864 static int __init adu_init(void)
865 {
866 	int result;
867 
868 	dbg(2," %s : enter", __FUNCTION__);
869 
870 	/* register this driver with the USB subsystem */
871 	result = usb_register(&adu_driver);
872 	if (result < 0) {
873 		err("usb_register failed for the "__FILE__" driver. "
874 		    "Error number %d", result);
875 		goto exit;
876 	}
877 
878 	info("adutux " DRIVER_DESC " " DRIVER_VERSION);
879 	info("adutux is an experimental driver. Use at your own risk");
880 
881 exit:
882 	dbg(2," %s : leave, return value %d", __FUNCTION__, result);
883 
884 	return result;
885 }
886 
887 static void __exit adu_exit(void)
888 {
889 	dbg(2," %s : enter", __FUNCTION__);
890 	/* deregister this driver with the USB subsystem */
891 	usb_deregister(&adu_driver);
892 	dbg(2," %s : leave", __FUNCTION__);
893 }
894 
895 module_init(adu_init);
896 module_exit(adu_exit);
897 
898 MODULE_AUTHOR(DRIVER_AUTHOR);
899 MODULE_DESCRIPTION(DRIVER_DESC);
900 MODULE_LICENSE("GPL");
901