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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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22 
23 #include <linux/kernel.h>
24 #include <linux/errno.h>
25 #include <linux/slab.h>
26 #include <linux/module.h>
27 #include <linux/usb.h>
28 #include <linux/mutex.h>
29 #include <linux/uaccess.h>
30 
31 /* Version Information */
32 #define DRIVER_VERSION "v0.0.13"
33 #define DRIVER_AUTHOR "John Homppi"
34 #define DRIVER_DESC "adutux (see www.ontrak.net)"
35 
36 /* Define these values to match your device */
37 #define ADU_VENDOR_ID 0x0a07
38 #define ADU_PRODUCT_ID 0x0064
39 
40 /* table of devices that work with this driver */
41 static const struct usb_device_id device_table[] = {
42 	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID) },		/* ADU100 */
43 	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+20) },	/* ADU120 */
44 	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+30) },	/* ADU130 */
45 	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+100) },	/* ADU200 */
46 	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+108) },	/* ADU208 */
47 	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+118) },	/* ADU218 */
48 	{ } /* Terminating entry */
49 };
50 
51 MODULE_DEVICE_TABLE(usb, device_table);
52 
53 #ifdef CONFIG_USB_DYNAMIC_MINORS
54 #define ADU_MINOR_BASE	0
55 #else
56 #define ADU_MINOR_BASE	67
57 #endif
58 
59 /* we can have up to this number of device plugged in at once */
60 #define MAX_DEVICES	16
61 
62 #define COMMAND_TIMEOUT	(2*HZ)	/* 60 second timeout for a command */
63 
64 /*
65  * The locking scheme is a vanilla 3-lock:
66  *   adu_device.buflock: A spinlock, covers what IRQs touch.
67  *   adutux_mutex:       A Static lock to cover open_count. It would also cover
68  *                       any globals, but we don't have them in 2.6.
69  *   adu_device.mtx:     A mutex to hold across sleepers like copy_from_user.
70  *                       It covers all of adu_device, except the open_count
71  *                       and what .buflock covers.
72  */
73 
74 /* Structure to hold all of our device specific stuff */
75 struct adu_device {
76 	struct mutex		mtx;
77 	struct usb_device *udev; /* save off the usb device pointer */
78 	struct usb_interface *interface;
79 	unsigned int		minor; /* the starting minor number for this device */
80 	char			serial_number[8];
81 
82 	int			open_count; /* number of times this port has been opened */
83 	unsigned long		disconnected:1;
84 
85 	char		*read_buffer_primary;
86 	int			read_buffer_length;
87 	char		*read_buffer_secondary;
88 	int			secondary_head;
89 	int			secondary_tail;
90 	spinlock_t		buflock;
91 
92 	wait_queue_head_t	read_wait;
93 	wait_queue_head_t	write_wait;
94 
95 	char		*interrupt_in_buffer;
96 	struct usb_endpoint_descriptor *interrupt_in_endpoint;
97 	struct urb	*interrupt_in_urb;
98 	int			read_urb_finished;
99 
100 	char		*interrupt_out_buffer;
101 	struct usb_endpoint_descriptor *interrupt_out_endpoint;
102 	struct urb	*interrupt_out_urb;
103 	int			out_urb_finished;
104 };
105 
106 static DEFINE_MUTEX(adutux_mutex);
107 
108 static struct usb_driver adu_driver;
109 
adu_debug_data(struct device * dev,const char * function,int size,const unsigned char * data)110 static inline void adu_debug_data(struct device *dev, const char *function,
111 				  int size, const unsigned char *data)
112 {
113 	dev_dbg(dev, "%s - length = %d, data = %*ph\n",
114 		function, size, size, data);
115 }
116 
117 /**
118  * adu_abort_transfers
119  *      aborts transfers and frees associated data structures
120  */
adu_abort_transfers(struct adu_device * dev)121 static void adu_abort_transfers(struct adu_device *dev)
122 {
123 	unsigned long flags;
124 
125 	if (dev->disconnected)
126 		return;
127 
128 	/* shutdown transfer */
129 
130 	/* XXX Anchor these instead */
131 	spin_lock_irqsave(&dev->buflock, flags);
132 	if (!dev->read_urb_finished) {
133 		spin_unlock_irqrestore(&dev->buflock, flags);
134 		usb_kill_urb(dev->interrupt_in_urb);
135 	} else
136 		spin_unlock_irqrestore(&dev->buflock, flags);
137 
138 	spin_lock_irqsave(&dev->buflock, flags);
139 	if (!dev->out_urb_finished) {
140 		spin_unlock_irqrestore(&dev->buflock, flags);
141 		usb_kill_urb(dev->interrupt_out_urb);
142 	} else
143 		spin_unlock_irqrestore(&dev->buflock, flags);
144 }
145 
adu_delete(struct adu_device * dev)146 static void adu_delete(struct adu_device *dev)
147 {
148 	/* free data structures */
149 	usb_free_urb(dev->interrupt_in_urb);
150 	usb_free_urb(dev->interrupt_out_urb);
151 	kfree(dev->read_buffer_primary);
152 	kfree(dev->read_buffer_secondary);
153 	kfree(dev->interrupt_in_buffer);
154 	kfree(dev->interrupt_out_buffer);
155 	usb_put_dev(dev->udev);
156 	kfree(dev);
157 }
158 
adu_interrupt_in_callback(struct urb * urb)159 static void adu_interrupt_in_callback(struct urb *urb)
160 {
161 	struct adu_device *dev = urb->context;
162 	int status = urb->status;
163 
164 	adu_debug_data(&dev->udev->dev, __func__,
165 		       urb->actual_length, urb->transfer_buffer);
166 
167 	spin_lock(&dev->buflock);
168 
169 	if (status != 0) {
170 		if ((status != -ENOENT) && (status != -ECONNRESET) &&
171 			(status != -ESHUTDOWN)) {
172 			dev_dbg(&dev->udev->dev,
173 				"%s : nonzero status received: %d\n",
174 				__func__, status);
175 		}
176 		goto exit;
177 	}
178 
179 	if (urb->actual_length > 0 && dev->interrupt_in_buffer[0] != 0x00) {
180 		if (dev->read_buffer_length <
181 		    (4 * usb_endpoint_maxp(dev->interrupt_in_endpoint)) -
182 		     (urb->actual_length)) {
183 			memcpy (dev->read_buffer_primary +
184 				dev->read_buffer_length,
185 				dev->interrupt_in_buffer, urb->actual_length);
186 
187 			dev->read_buffer_length += urb->actual_length;
188 			dev_dbg(&dev->udev->dev,"%s reading  %d\n", __func__,
189 				urb->actual_length);
190 		} else {
191 			dev_dbg(&dev->udev->dev,"%s : read_buffer overflow\n",
192 				__func__);
193 		}
194 	}
195 
196 exit:
197 	dev->read_urb_finished = 1;
198 	spin_unlock(&dev->buflock);
199 	/* always wake up so we recover from errors */
200 	wake_up_interruptible(&dev->read_wait);
201 }
202 
adu_interrupt_out_callback(struct urb * urb)203 static void adu_interrupt_out_callback(struct urb *urb)
204 {
205 	struct adu_device *dev = urb->context;
206 	int status = urb->status;
207 
208 	adu_debug_data(&dev->udev->dev, __func__,
209 		       urb->actual_length, urb->transfer_buffer);
210 
211 	if (status != 0) {
212 		if ((status != -ENOENT) &&
213 		    (status != -ESHUTDOWN) &&
214 		    (status != -ECONNRESET)) {
215 			dev_dbg(&dev->udev->dev,
216 				"%s :nonzero status received: %d\n", __func__,
217 				status);
218 		}
219 		return;
220 	}
221 
222 	spin_lock(&dev->buflock);
223 	dev->out_urb_finished = 1;
224 	wake_up(&dev->write_wait);
225 	spin_unlock(&dev->buflock);
226 }
227 
adu_open(struct inode * inode,struct file * file)228 static int adu_open(struct inode *inode, struct file *file)
229 {
230 	struct adu_device *dev = NULL;
231 	struct usb_interface *interface;
232 	int subminor;
233 	int retval;
234 
235 	subminor = iminor(inode);
236 
237 	retval = mutex_lock_interruptible(&adutux_mutex);
238 	if (retval)
239 		goto exit_no_lock;
240 
241 	interface = usb_find_interface(&adu_driver, subminor);
242 	if (!interface) {
243 		pr_err("%s - error, can't find device for minor %d\n",
244 		       __func__, subminor);
245 		retval = -ENODEV;
246 		goto exit_no_device;
247 	}
248 
249 	dev = usb_get_intfdata(interface);
250 	if (!dev) {
251 		retval = -ENODEV;
252 		goto exit_no_device;
253 	}
254 
255 	/* check that nobody else is using the device */
256 	if (dev->open_count) {
257 		retval = -EBUSY;
258 		goto exit_no_device;
259 	}
260 
261 	++dev->open_count;
262 	dev_dbg(&dev->udev->dev, "%s: open count %d\n", __func__,
263 		dev->open_count);
264 
265 	/* save device in the file's private structure */
266 	file->private_data = dev;
267 
268 	/* initialize in direction */
269 	dev->read_buffer_length = 0;
270 
271 	/* fixup first read by having urb waiting for it */
272 	usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
273 			 usb_rcvintpipe(dev->udev,
274 					dev->interrupt_in_endpoint->bEndpointAddress),
275 			 dev->interrupt_in_buffer,
276 			 usb_endpoint_maxp(dev->interrupt_in_endpoint),
277 			 adu_interrupt_in_callback, dev,
278 			 dev->interrupt_in_endpoint->bInterval);
279 	dev->read_urb_finished = 0;
280 	if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL))
281 		dev->read_urb_finished = 1;
282 	/* we ignore failure */
283 	/* end of fixup for first read */
284 
285 	/* initialize out direction */
286 	dev->out_urb_finished = 1;
287 
288 	retval = 0;
289 
290 exit_no_device:
291 	mutex_unlock(&adutux_mutex);
292 exit_no_lock:
293 	return retval;
294 }
295 
adu_release_internal(struct adu_device * dev)296 static void adu_release_internal(struct adu_device *dev)
297 {
298 	/* decrement our usage count for the device */
299 	--dev->open_count;
300 	dev_dbg(&dev->udev->dev, "%s : open count %d\n", __func__,
301 		dev->open_count);
302 	if (dev->open_count <= 0) {
303 		adu_abort_transfers(dev);
304 		dev->open_count = 0;
305 	}
306 }
307 
adu_release(struct inode * inode,struct file * file)308 static int adu_release(struct inode *inode, struct file *file)
309 {
310 	struct adu_device *dev;
311 	int retval = 0;
312 
313 	if (file == NULL) {
314 		retval = -ENODEV;
315 		goto exit;
316 	}
317 
318 	dev = file->private_data;
319 	if (dev == NULL) {
320 		retval = -ENODEV;
321 		goto exit;
322 	}
323 
324 	mutex_lock(&adutux_mutex); /* not interruptible */
325 
326 	if (dev->open_count <= 0) {
327 		dev_dbg(&dev->udev->dev, "%s : device not opened\n", __func__);
328 		retval = -ENODEV;
329 		goto unlock;
330 	}
331 
332 	adu_release_internal(dev);
333 	if (dev->disconnected) {
334 		/* the device was unplugged before the file was released */
335 		if (!dev->open_count)	/* ... and we're the last user */
336 			adu_delete(dev);
337 	}
338 unlock:
339 	mutex_unlock(&adutux_mutex);
340 exit:
341 	return retval;
342 }
343 
adu_read(struct file * file,__user char * buffer,size_t count,loff_t * ppos)344 static ssize_t adu_read(struct file *file, __user char *buffer, size_t count,
345 			loff_t *ppos)
346 {
347 	struct adu_device *dev;
348 	size_t bytes_read = 0;
349 	size_t bytes_to_read = count;
350 	int i;
351 	int retval = 0;
352 	int timeout = 0;
353 	int should_submit = 0;
354 	unsigned long flags;
355 	DECLARE_WAITQUEUE(wait, current);
356 
357 	dev = file->private_data;
358 	if (mutex_lock_interruptible(&dev->mtx))
359 		return -ERESTARTSYS;
360 
361 	/* verify that the device wasn't unplugged */
362 	if (dev->disconnected) {
363 		retval = -ENODEV;
364 		pr_err("No device or device unplugged %d\n", retval);
365 		goto exit;
366 	}
367 
368 	/* verify that some data was requested */
369 	if (count == 0) {
370 		dev_dbg(&dev->udev->dev, "%s : read request of 0 bytes\n",
371 			__func__);
372 		goto exit;
373 	}
374 
375 	timeout = COMMAND_TIMEOUT;
376 	dev_dbg(&dev->udev->dev, "%s : about to start looping\n", __func__);
377 	while (bytes_to_read) {
378 		int data_in_secondary = dev->secondary_tail - dev->secondary_head;
379 		dev_dbg(&dev->udev->dev,
380 			"%s : while, data_in_secondary=%d, status=%d\n",
381 			__func__, data_in_secondary,
382 			dev->interrupt_in_urb->status);
383 
384 		if (data_in_secondary) {
385 			/* drain secondary buffer */
386 			int amount = bytes_to_read < data_in_secondary ? bytes_to_read : data_in_secondary;
387 			i = copy_to_user(buffer, dev->read_buffer_secondary+dev->secondary_head, amount);
388 			if (i) {
389 				retval = -EFAULT;
390 				goto exit;
391 			}
392 			dev->secondary_head += (amount - i);
393 			bytes_read += (amount - i);
394 			bytes_to_read -= (amount - i);
395 			if (i) {
396 				retval = bytes_read ? bytes_read : -EFAULT;
397 				goto exit;
398 			}
399 		} else {
400 			/* we check the primary buffer */
401 			spin_lock_irqsave (&dev->buflock, flags);
402 			if (dev->read_buffer_length) {
403 				/* we secure access to the primary */
404 				char *tmp;
405 				dev_dbg(&dev->udev->dev,
406 					"%s : swap, read_buffer_length = %d\n",
407 					__func__, dev->read_buffer_length);
408 				tmp = dev->read_buffer_secondary;
409 				dev->read_buffer_secondary = dev->read_buffer_primary;
410 				dev->read_buffer_primary = tmp;
411 				dev->secondary_head = 0;
412 				dev->secondary_tail = dev->read_buffer_length;
413 				dev->read_buffer_length = 0;
414 				spin_unlock_irqrestore(&dev->buflock, flags);
415 				/* we have a free buffer so use it */
416 				should_submit = 1;
417 			} else {
418 				/* even the primary was empty - we may need to do IO */
419 				if (!dev->read_urb_finished) {
420 					/* somebody is doing IO */
421 					spin_unlock_irqrestore(&dev->buflock, flags);
422 					dev_dbg(&dev->udev->dev,
423 						"%s : submitted already\n",
424 						__func__);
425 				} else {
426 					/* we must initiate input */
427 					dev_dbg(&dev->udev->dev,
428 						"%s : initiate input\n",
429 						__func__);
430 					dev->read_urb_finished = 0;
431 					spin_unlock_irqrestore(&dev->buflock, flags);
432 
433 					usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
434 							usb_rcvintpipe(dev->udev,
435 								dev->interrupt_in_endpoint->bEndpointAddress),
436 							 dev->interrupt_in_buffer,
437 							 usb_endpoint_maxp(dev->interrupt_in_endpoint),
438 							 adu_interrupt_in_callback,
439 							 dev,
440 							 dev->interrupt_in_endpoint->bInterval);
441 					retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
442 					if (retval) {
443 						dev->read_urb_finished = 1;
444 						if (retval == -ENOMEM) {
445 							retval = bytes_read ? bytes_read : -ENOMEM;
446 						}
447 						dev_dbg(&dev->udev->dev,
448 							"%s : submit failed\n",
449 							__func__);
450 						goto exit;
451 					}
452 				}
453 
454 				/* we wait for I/O to complete */
455 				set_current_state(TASK_INTERRUPTIBLE);
456 				add_wait_queue(&dev->read_wait, &wait);
457 				spin_lock_irqsave(&dev->buflock, flags);
458 				if (!dev->read_urb_finished) {
459 					spin_unlock_irqrestore(&dev->buflock, flags);
460 					timeout = schedule_timeout(COMMAND_TIMEOUT);
461 				} else {
462 					spin_unlock_irqrestore(&dev->buflock, flags);
463 					set_current_state(TASK_RUNNING);
464 				}
465 				remove_wait_queue(&dev->read_wait, &wait);
466 
467 				if (timeout <= 0) {
468 					dev_dbg(&dev->udev->dev,
469 						"%s : timeout\n", __func__);
470 					retval = bytes_read ? bytes_read : -ETIMEDOUT;
471 					goto exit;
472 				}
473 
474 				if (signal_pending(current)) {
475 					dev_dbg(&dev->udev->dev,
476 						"%s : signal pending\n",
477 						__func__);
478 					retval = bytes_read ? bytes_read : -EINTR;
479 					goto exit;
480 				}
481 			}
482 		}
483 	}
484 
485 	retval = bytes_read;
486 	/* if the primary buffer is empty then use it */
487 	spin_lock_irqsave(&dev->buflock, flags);
488 	if (should_submit && dev->read_urb_finished) {
489 		dev->read_urb_finished = 0;
490 		spin_unlock_irqrestore(&dev->buflock, flags);
491 		usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
492 				 usb_rcvintpipe(dev->udev,
493 					dev->interrupt_in_endpoint->bEndpointAddress),
494 				dev->interrupt_in_buffer,
495 				usb_endpoint_maxp(dev->interrupt_in_endpoint),
496 				adu_interrupt_in_callback,
497 				dev,
498 				dev->interrupt_in_endpoint->bInterval);
499 		if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL) != 0)
500 			dev->read_urb_finished = 1;
501 		/* we ignore failure */
502 	} else {
503 		spin_unlock_irqrestore(&dev->buflock, flags);
504 	}
505 
506 exit:
507 	/* unlock the device */
508 	mutex_unlock(&dev->mtx);
509 
510 	return retval;
511 }
512 
adu_write(struct file * file,const __user char * buffer,size_t count,loff_t * ppos)513 static ssize_t adu_write(struct file *file, const __user char *buffer,
514 			 size_t count, loff_t *ppos)
515 {
516 	DECLARE_WAITQUEUE(waita, current);
517 	struct adu_device *dev;
518 	size_t bytes_written = 0;
519 	size_t bytes_to_write;
520 	size_t buffer_size;
521 	unsigned long flags;
522 	int retval;
523 
524 	dev = file->private_data;
525 
526 	retval = mutex_lock_interruptible(&dev->mtx);
527 	if (retval)
528 		goto exit_nolock;
529 
530 	/* verify that the device wasn't unplugged */
531 	if (dev->disconnected) {
532 		retval = -ENODEV;
533 		pr_err("No device or device unplugged %d\n", retval);
534 		goto exit;
535 	}
536 
537 	/* verify that we actually have some data to write */
538 	if (count == 0) {
539 		dev_dbg(&dev->udev->dev, "%s : write request of 0 bytes\n",
540 			__func__);
541 		goto exit;
542 	}
543 
544 	while (count > 0) {
545 		add_wait_queue(&dev->write_wait, &waita);
546 		set_current_state(TASK_INTERRUPTIBLE);
547 		spin_lock_irqsave(&dev->buflock, flags);
548 		if (!dev->out_urb_finished) {
549 			spin_unlock_irqrestore(&dev->buflock, flags);
550 
551 			mutex_unlock(&dev->mtx);
552 			if (signal_pending(current)) {
553 				dev_dbg(&dev->udev->dev, "%s : interrupted\n",
554 					__func__);
555 				set_current_state(TASK_RUNNING);
556 				retval = -EINTR;
557 				goto exit_onqueue;
558 			}
559 			if (schedule_timeout(COMMAND_TIMEOUT) == 0) {
560 				dev_dbg(&dev->udev->dev,
561 					"%s - command timed out.\n", __func__);
562 				retval = -ETIMEDOUT;
563 				goto exit_onqueue;
564 			}
565 			remove_wait_queue(&dev->write_wait, &waita);
566 			retval = mutex_lock_interruptible(&dev->mtx);
567 			if (retval) {
568 				retval = bytes_written ? bytes_written : retval;
569 				goto exit_nolock;
570 			}
571 
572 			dev_dbg(&dev->udev->dev,
573 				"%s : in progress, count = %Zd\n",
574 				__func__, count);
575 		} else {
576 			spin_unlock_irqrestore(&dev->buflock, flags);
577 			set_current_state(TASK_RUNNING);
578 			remove_wait_queue(&dev->write_wait, &waita);
579 			dev_dbg(&dev->udev->dev, "%s : sending, count = %Zd\n",
580 				__func__, count);
581 
582 			/* write the data into interrupt_out_buffer from userspace */
583 			buffer_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
584 			bytes_to_write = count > buffer_size ? buffer_size : count;
585 			dev_dbg(&dev->udev->dev,
586 				"%s : buffer_size = %Zd, count = %Zd, bytes_to_write = %Zd\n",
587 				__func__, buffer_size, count, bytes_to_write);
588 
589 			if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write) != 0) {
590 				retval = -EFAULT;
591 				goto exit;
592 			}
593 
594 			/* send off the urb */
595 			usb_fill_int_urb(
596 				dev->interrupt_out_urb,
597 				dev->udev,
598 				usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
599 				dev->interrupt_out_buffer,
600 				bytes_to_write,
601 				adu_interrupt_out_callback,
602 				dev,
603 				dev->interrupt_out_endpoint->bInterval);
604 			dev->interrupt_out_urb->actual_length = bytes_to_write;
605 			dev->out_urb_finished = 0;
606 			retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
607 			if (retval < 0) {
608 				dev->out_urb_finished = 1;
609 				dev_err(&dev->udev->dev, "Couldn't submit "
610 					"interrupt_out_urb %d\n", retval);
611 				goto exit;
612 			}
613 
614 			buffer += bytes_to_write;
615 			count -= bytes_to_write;
616 
617 			bytes_written += bytes_to_write;
618 		}
619 	}
620 	mutex_unlock(&dev->mtx);
621 	return bytes_written;
622 
623 exit:
624 	mutex_unlock(&dev->mtx);
625 exit_nolock:
626 	return retval;
627 
628 exit_onqueue:
629 	remove_wait_queue(&dev->write_wait, &waita);
630 	return retval;
631 }
632 
633 /* file operations needed when we register this driver */
634 static const struct file_operations adu_fops = {
635 	.owner = THIS_MODULE,
636 	.read  = adu_read,
637 	.write = adu_write,
638 	.open = adu_open,
639 	.release = adu_release,
640 	.llseek = noop_llseek,
641 };
642 
643 /*
644  * usb class driver info in order to get a minor number from the usb core,
645  * and to have the device registered with devfs and the driver core
646  */
647 static struct usb_class_driver adu_class = {
648 	.name = "usb/adutux%d",
649 	.fops = &adu_fops,
650 	.minor_base = ADU_MINOR_BASE,
651 };
652 
653 /**
654  * adu_probe
655  *
656  * Called by the usb core when a new device is connected that it thinks
657  * this driver might be interested in.
658  */
adu_probe(struct usb_interface * interface,const struct usb_device_id * id)659 static int adu_probe(struct usb_interface *interface,
660 		     const struct usb_device_id *id)
661 {
662 	struct usb_device *udev = interface_to_usbdev(interface);
663 	struct adu_device *dev = NULL;
664 	struct usb_host_interface *iface_desc;
665 	struct usb_endpoint_descriptor *endpoint;
666 	int retval = -ENODEV;
667 	int in_end_size;
668 	int out_end_size;
669 	int i;
670 
671 	if (udev == NULL) {
672 		dev_err(&interface->dev, "udev is NULL.\n");
673 		goto exit;
674 	}
675 
676 	/* allocate memory for our device state and initialize it */
677 	dev = kzalloc(sizeof(struct adu_device), GFP_KERNEL);
678 	if (dev == NULL) {
679 		dev_err(&interface->dev, "Out of memory\n");
680 		retval = -ENOMEM;
681 		goto exit;
682 	}
683 
684 	mutex_init(&dev->mtx);
685 	spin_lock_init(&dev->buflock);
686 	dev->udev = usb_get_dev(udev);
687 	init_waitqueue_head(&dev->read_wait);
688 	init_waitqueue_head(&dev->write_wait);
689 
690 	iface_desc = &interface->cur_altsetting[0];
691 
692 	/* set up the endpoint information */
693 	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
694 		endpoint = &iface_desc->endpoint[i].desc;
695 
696 		if (usb_endpoint_is_int_in(endpoint))
697 			dev->interrupt_in_endpoint = endpoint;
698 
699 		if (usb_endpoint_is_int_out(endpoint))
700 			dev->interrupt_out_endpoint = endpoint;
701 	}
702 	if (dev->interrupt_in_endpoint == NULL) {
703 		dev_err(&interface->dev, "interrupt in endpoint not found\n");
704 		goto error;
705 	}
706 	if (dev->interrupt_out_endpoint == NULL) {
707 		dev_err(&interface->dev, "interrupt out endpoint not found\n");
708 		goto error;
709 	}
710 
711 	in_end_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
712 	out_end_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
713 
714 	dev->read_buffer_primary = kmalloc((4 * in_end_size), GFP_KERNEL);
715 	if (!dev->read_buffer_primary) {
716 		dev_err(&interface->dev, "Couldn't allocate read_buffer_primary\n");
717 		retval = -ENOMEM;
718 		goto error;
719 	}
720 
721 	/* debug code prime the buffer */
722 	memset(dev->read_buffer_primary, 'a', in_end_size);
723 	memset(dev->read_buffer_primary + in_end_size, 'b', in_end_size);
724 	memset(dev->read_buffer_primary + (2 * in_end_size), 'c', in_end_size);
725 	memset(dev->read_buffer_primary + (3 * in_end_size), 'd', in_end_size);
726 
727 	dev->read_buffer_secondary = kmalloc((4 * in_end_size), GFP_KERNEL);
728 	if (!dev->read_buffer_secondary) {
729 		dev_err(&interface->dev, "Couldn't allocate read_buffer_secondary\n");
730 		retval = -ENOMEM;
731 		goto error;
732 	}
733 
734 	/* debug code prime the buffer */
735 	memset(dev->read_buffer_secondary, 'e', in_end_size);
736 	memset(dev->read_buffer_secondary + in_end_size, 'f', in_end_size);
737 	memset(dev->read_buffer_secondary + (2 * in_end_size), 'g', in_end_size);
738 	memset(dev->read_buffer_secondary + (3 * in_end_size), 'h', in_end_size);
739 
740 	dev->interrupt_in_buffer = kmalloc(in_end_size, GFP_KERNEL);
741 	if (!dev->interrupt_in_buffer) {
742 		dev_err(&interface->dev, "Couldn't allocate interrupt_in_buffer\n");
743 		goto error;
744 	}
745 
746 	/* debug code prime the buffer */
747 	memset(dev->interrupt_in_buffer, 'i', in_end_size);
748 
749 	dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
750 	if (!dev->interrupt_in_urb) {
751 		dev_err(&interface->dev, "Couldn't allocate interrupt_in_urb\n");
752 		goto error;
753 	}
754 	dev->interrupt_out_buffer = kmalloc(out_end_size, GFP_KERNEL);
755 	if (!dev->interrupt_out_buffer) {
756 		dev_err(&interface->dev, "Couldn't allocate interrupt_out_buffer\n");
757 		goto error;
758 	}
759 	dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
760 	if (!dev->interrupt_out_urb) {
761 		dev_err(&interface->dev, "Couldn't allocate interrupt_out_urb\n");
762 		goto error;
763 	}
764 
765 	if (!usb_string(udev, udev->descriptor.iSerialNumber, dev->serial_number,
766 			sizeof(dev->serial_number))) {
767 		dev_err(&interface->dev, "Could not retrieve serial number\n");
768 		goto error;
769 	}
770 	dev_dbg(&interface->dev,"serial_number=%s", dev->serial_number);
771 
772 	/* we can register the device now, as it is ready */
773 	usb_set_intfdata(interface, dev);
774 
775 	retval = usb_register_dev(interface, &adu_class);
776 
777 	if (retval) {
778 		/* something prevented us from registering this driver */
779 		dev_err(&interface->dev, "Not able to get a minor for this device.\n");
780 		usb_set_intfdata(interface, NULL);
781 		goto error;
782 	}
783 
784 	dev->minor = interface->minor;
785 
786 	/* let the user know what node this device is now attached to */
787 	dev_info(&interface->dev, "ADU%d %s now attached to /dev/usb/adutux%d\n",
788 		 le16_to_cpu(udev->descriptor.idProduct), dev->serial_number,
789 		 (dev->minor - ADU_MINOR_BASE));
790 exit:
791 	return retval;
792 
793 error:
794 	adu_delete(dev);
795 	return retval;
796 }
797 
798 /**
799  * adu_disconnect
800  *
801  * Called by the usb core when the device is removed from the system.
802  */
adu_disconnect(struct usb_interface * interface)803 static void adu_disconnect(struct usb_interface *interface)
804 {
805 	struct adu_device *dev;
806 
807 	dev = usb_get_intfdata(interface);
808 
809 	usb_deregister_dev(interface, &adu_class);
810 
811 	usb_poison_urb(dev->interrupt_in_urb);
812 	usb_poison_urb(dev->interrupt_out_urb);
813 
814 	mutex_lock(&adutux_mutex);
815 	usb_set_intfdata(interface, NULL);
816 
817 	mutex_lock(&dev->mtx);	/* not interruptible */
818 	dev->disconnected = 1;
819 	mutex_unlock(&dev->mtx);
820 
821 	/* if the device is not opened, then we clean up right now */
822 	if (!dev->open_count)
823 		adu_delete(dev);
824 
825 	mutex_unlock(&adutux_mutex);
826 }
827 
828 /* usb specific object needed to register this driver with the usb subsystem */
829 static struct usb_driver adu_driver = {
830 	.name = "adutux",
831 	.probe = adu_probe,
832 	.disconnect = adu_disconnect,
833 	.id_table = device_table,
834 };
835 
836 module_usb_driver(adu_driver);
837 
838 MODULE_AUTHOR(DRIVER_AUTHOR);
839 MODULE_DESCRIPTION(DRIVER_DESC);
840 MODULE_LICENSE("GPL");
841