xref: /linux/drivers/usb/misc/iowarrior.c (revision f3539c12d8196ce0a1993364d30b3a18908470d1)
1 /*
2  *  Native support for the I/O-Warrior USB devices
3  *
4  *  Copyright (c) 2003-2005  Code Mercenaries GmbH
5  *  written by Christian Lucht <lucht@codemercs.com>
6  *
7  *  based on
8 
9  *  usb-skeleton.c by Greg Kroah-Hartman  <greg@kroah.com>
10  *  brlvger.c by Stephane Dalton  <sdalton@videotron.ca>
11  *           and St�hane Doyon   <s.doyon@videotron.ca>
12  *
13  *  Released under the GPLv2.
14  */
15 
16 #include <linux/module.h>
17 #include <linux/usb.h>
18 #include <linux/slab.h>
19 #include <linux/sched.h>
20 #include <linux/mutex.h>
21 #include <linux/poll.h>
22 #include <linux/usb/iowarrior.h>
23 
24 /* Version Information */
25 #define DRIVER_VERSION "v0.4.0"
26 #define DRIVER_AUTHOR "Christian Lucht <lucht@codemercs.com>"
27 #define DRIVER_DESC "USB IO-Warrior driver (Linux 2.6.x)"
28 
29 #define USB_VENDOR_ID_CODEMERCS		1984
30 /* low speed iowarrior */
31 #define USB_DEVICE_ID_CODEMERCS_IOW40	0x1500
32 #define USB_DEVICE_ID_CODEMERCS_IOW24	0x1501
33 #define USB_DEVICE_ID_CODEMERCS_IOWPV1	0x1511
34 #define USB_DEVICE_ID_CODEMERCS_IOWPV2	0x1512
35 /* full speed iowarrior */
36 #define USB_DEVICE_ID_CODEMERCS_IOW56	0x1503
37 
38 /* Get a minor range for your devices from the usb maintainer */
39 #ifdef CONFIG_USB_DYNAMIC_MINORS
40 #define IOWARRIOR_MINOR_BASE	0
41 #else
42 #define IOWARRIOR_MINOR_BASE	208	// SKELETON_MINOR_BASE 192 + 16, not official yet
43 #endif
44 
45 /* interrupt input queue size */
46 #define MAX_INTERRUPT_BUFFER 16
47 /*
48    maximum number of urbs that are submitted for writes at the same time,
49    this applies to the IOWarrior56 only!
50    IOWarrior24 and IOWarrior40 use synchronous usb_control_msg calls.
51 */
52 #define MAX_WRITES_IN_FLIGHT 4
53 
54 MODULE_AUTHOR(DRIVER_AUTHOR);
55 MODULE_DESCRIPTION(DRIVER_DESC);
56 MODULE_LICENSE("GPL");
57 
58 /* Module parameters */
59 static DEFINE_MUTEX(iowarrior_mutex);
60 
61 static struct usb_driver iowarrior_driver;
62 static DEFINE_MUTEX(iowarrior_open_disc_lock);
63 
64 /*--------------*/
65 /*     data     */
66 /*--------------*/
67 
68 /* Structure to hold all of our device specific stuff */
69 struct iowarrior {
70 	struct mutex mutex;			/* locks this structure */
71 	struct usb_device *udev;		/* save off the usb device pointer */
72 	struct usb_interface *interface;	/* the interface for this device */
73 	unsigned char minor;			/* the starting minor number for this device */
74 	struct usb_endpoint_descriptor *int_out_endpoint;	/* endpoint for reading (needed for IOW56 only) */
75 	struct usb_endpoint_descriptor *int_in_endpoint;	/* endpoint for reading */
76 	struct urb *int_in_urb;		/* the urb for reading data */
77 	unsigned char *int_in_buffer;	/* buffer for data to be read */
78 	unsigned char serial_number;	/* to detect lost packages */
79 	unsigned char *read_queue;	/* size is MAX_INTERRUPT_BUFFER * packet size */
80 	wait_queue_head_t read_wait;
81 	wait_queue_head_t write_wait;	/* wait-queue for writing to the device */
82 	atomic_t write_busy;		/* number of write-urbs submitted */
83 	atomic_t read_idx;
84 	atomic_t intr_idx;
85 	spinlock_t intr_idx_lock;	/* protects intr_idx */
86 	atomic_t overflow_flag;		/* signals an index 'rollover' */
87 	int present;			/* this is 1 as long as the device is connected */
88 	int opened;			/* this is 1 if the device is currently open */
89 	char chip_serial[9];		/* the serial number string of the chip connected */
90 	int report_size;		/* number of bytes in a report */
91 	u16 product_id;
92 };
93 
94 /*--------------*/
95 /*    globals   */
96 /*--------------*/
97 
98 /*
99  *  USB spec identifies 5 second timeouts.
100  */
101 #define GET_TIMEOUT 5
102 #define USB_REQ_GET_REPORT  0x01
103 //#if 0
104 static int usb_get_report(struct usb_device *dev,
105 			  struct usb_host_interface *inter, unsigned char type,
106 			  unsigned char id, void *buf, int size)
107 {
108 	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
109 			       USB_REQ_GET_REPORT,
110 			       USB_DIR_IN | USB_TYPE_CLASS |
111 			       USB_RECIP_INTERFACE, (type << 8) + id,
112 			       inter->desc.bInterfaceNumber, buf, size,
113 			       GET_TIMEOUT*HZ);
114 }
115 //#endif
116 
117 #define USB_REQ_SET_REPORT 0x09
118 
119 static int usb_set_report(struct usb_interface *intf, unsigned char type,
120 			  unsigned char id, void *buf, int size)
121 {
122 	return usb_control_msg(interface_to_usbdev(intf),
123 			       usb_sndctrlpipe(interface_to_usbdev(intf), 0),
124 			       USB_REQ_SET_REPORT,
125 			       USB_TYPE_CLASS | USB_RECIP_INTERFACE,
126 			       (type << 8) + id,
127 			       intf->cur_altsetting->desc.bInterfaceNumber, buf,
128 			       size, HZ);
129 }
130 
131 /*---------------------*/
132 /* driver registration */
133 /*---------------------*/
134 /* table of devices that work with this driver */
135 static const struct usb_device_id iowarrior_ids[] = {
136 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW40)},
137 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW24)},
138 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV1)},
139 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV2)},
140 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW56)},
141 	{}			/* Terminating entry */
142 };
143 MODULE_DEVICE_TABLE(usb, iowarrior_ids);
144 
145 /*
146  * USB callback handler for reading data
147  */
148 static void iowarrior_callback(struct urb *urb)
149 {
150 	struct iowarrior *dev = urb->context;
151 	int intr_idx;
152 	int read_idx;
153 	int aux_idx;
154 	int offset;
155 	int status = urb->status;
156 	int retval;
157 
158 	switch (status) {
159 	case 0:
160 		/* success */
161 		break;
162 	case -ECONNRESET:
163 	case -ENOENT:
164 	case -ESHUTDOWN:
165 		return;
166 	default:
167 		goto exit;
168 	}
169 
170 	spin_lock(&dev->intr_idx_lock);
171 	intr_idx = atomic_read(&dev->intr_idx);
172 	/* aux_idx become previous intr_idx */
173 	aux_idx = (intr_idx == 0) ? (MAX_INTERRUPT_BUFFER - 1) : (intr_idx - 1);
174 	read_idx = atomic_read(&dev->read_idx);
175 
176 	/* queue is not empty and it's interface 0 */
177 	if ((intr_idx != read_idx)
178 	    && (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0)) {
179 		/* + 1 for serial number */
180 		offset = aux_idx * (dev->report_size + 1);
181 		if (!memcmp
182 		    (dev->read_queue + offset, urb->transfer_buffer,
183 		     dev->report_size)) {
184 			/* equal values on interface 0 will be ignored */
185 			spin_unlock(&dev->intr_idx_lock);
186 			goto exit;
187 		}
188 	}
189 
190 	/* aux_idx become next intr_idx */
191 	aux_idx = (intr_idx == (MAX_INTERRUPT_BUFFER - 1)) ? 0 : (intr_idx + 1);
192 	if (read_idx == aux_idx) {
193 		/* queue full, dropping oldest input */
194 		read_idx = (++read_idx == MAX_INTERRUPT_BUFFER) ? 0 : read_idx;
195 		atomic_set(&dev->read_idx, read_idx);
196 		atomic_set(&dev->overflow_flag, 1);
197 	}
198 
199 	/* +1 for serial number */
200 	offset = intr_idx * (dev->report_size + 1);
201 	memcpy(dev->read_queue + offset, urb->transfer_buffer,
202 	       dev->report_size);
203 	*(dev->read_queue + offset + (dev->report_size)) = dev->serial_number++;
204 
205 	atomic_set(&dev->intr_idx, aux_idx);
206 	spin_unlock(&dev->intr_idx_lock);
207 	/* tell the blocking read about the new data */
208 	wake_up_interruptible(&dev->read_wait);
209 
210 exit:
211 	retval = usb_submit_urb(urb, GFP_ATOMIC);
212 	if (retval)
213 		dev_err(&dev->interface->dev, "%s - usb_submit_urb failed with result %d\n",
214 			__func__, retval);
215 
216 }
217 
218 /*
219  * USB Callback handler for write-ops
220  */
221 static void iowarrior_write_callback(struct urb *urb)
222 {
223 	struct iowarrior *dev;
224 	int status = urb->status;
225 
226 	dev = urb->context;
227 	/* sync/async unlink faults aren't errors */
228 	if (status &&
229 	    !(status == -ENOENT ||
230 	      status == -ECONNRESET || status == -ESHUTDOWN)) {
231 		dev_dbg(&dev->interface->dev,
232 			"nonzero write bulk status received: %d\n", status);
233 	}
234 	/* free up our allocated buffer */
235 	usb_free_coherent(urb->dev, urb->transfer_buffer_length,
236 			  urb->transfer_buffer, urb->transfer_dma);
237 	/* tell a waiting writer the interrupt-out-pipe is available again */
238 	atomic_dec(&dev->write_busy);
239 	wake_up_interruptible(&dev->write_wait);
240 }
241 
242 /**
243  *	iowarrior_delete
244  */
245 static inline void iowarrior_delete(struct iowarrior *dev)
246 {
247 	dev_dbg(&dev->interface->dev, "minor %d\n", dev->minor);
248 	kfree(dev->int_in_buffer);
249 	usb_free_urb(dev->int_in_urb);
250 	kfree(dev->read_queue);
251 	kfree(dev);
252 }
253 
254 /*---------------------*/
255 /* fops implementation */
256 /*---------------------*/
257 
258 static int read_index(struct iowarrior *dev)
259 {
260 	int intr_idx, read_idx;
261 
262 	read_idx = atomic_read(&dev->read_idx);
263 	intr_idx = atomic_read(&dev->intr_idx);
264 
265 	return (read_idx == intr_idx ? -1 : read_idx);
266 }
267 
268 /**
269  *  iowarrior_read
270  */
271 static ssize_t iowarrior_read(struct file *file, char __user *buffer,
272 			      size_t count, loff_t *ppos)
273 {
274 	struct iowarrior *dev;
275 	int read_idx;
276 	int offset;
277 
278 	dev = file->private_data;
279 
280 	/* verify that the device wasn't unplugged */
281 	if (dev == NULL || !dev->present)
282 		return -ENODEV;
283 
284 	dev_dbg(&dev->interface->dev, "minor %d, count = %zd\n",
285 		dev->minor, count);
286 
287 	/* read count must be packet size (+ time stamp) */
288 	if ((count != dev->report_size)
289 	    && (count != (dev->report_size + 1)))
290 		return -EINVAL;
291 
292 	/* repeat until no buffer overrun in callback handler occur */
293 	do {
294 		atomic_set(&dev->overflow_flag, 0);
295 		if ((read_idx = read_index(dev)) == -1) {
296 			/* queue empty */
297 			if (file->f_flags & O_NONBLOCK)
298 				return -EAGAIN;
299 			else {
300 				//next line will return when there is either new data, or the device is unplugged
301 				int r = wait_event_interruptible(dev->read_wait,
302 								 (!dev->present
303 								  || (read_idx =
304 								      read_index
305 								      (dev)) !=
306 								  -1));
307 				if (r) {
308 					//we were interrupted by a signal
309 					return -ERESTART;
310 				}
311 				if (!dev->present) {
312 					//The device was unplugged
313 					return -ENODEV;
314 				}
315 				if (read_idx == -1) {
316 					// Can this happen ???
317 					return 0;
318 				}
319 			}
320 		}
321 
322 		offset = read_idx * (dev->report_size + 1);
323 		if (copy_to_user(buffer, dev->read_queue + offset, count)) {
324 			return -EFAULT;
325 		}
326 	} while (atomic_read(&dev->overflow_flag));
327 
328 	read_idx = ++read_idx == MAX_INTERRUPT_BUFFER ? 0 : read_idx;
329 	atomic_set(&dev->read_idx, read_idx);
330 	return count;
331 }
332 
333 /*
334  * iowarrior_write
335  */
336 static ssize_t iowarrior_write(struct file *file,
337 			       const char __user *user_buffer,
338 			       size_t count, loff_t *ppos)
339 {
340 	struct iowarrior *dev;
341 	int retval = 0;
342 	char *buf = NULL;	/* for IOW24 and IOW56 we need a buffer */
343 	struct urb *int_out_urb = NULL;
344 
345 	dev = file->private_data;
346 
347 	mutex_lock(&dev->mutex);
348 	/* verify that the device wasn't unplugged */
349 	if (!dev->present) {
350 		retval = -ENODEV;
351 		goto exit;
352 	}
353 	dev_dbg(&dev->interface->dev, "minor %d, count = %zd\n",
354 		dev->minor, count);
355 	/* if count is 0 we're already done */
356 	if (count == 0) {
357 		retval = 0;
358 		goto exit;
359 	}
360 	/* We only accept full reports */
361 	if (count != dev->report_size) {
362 		retval = -EINVAL;
363 		goto exit;
364 	}
365 	switch (dev->product_id) {
366 	case USB_DEVICE_ID_CODEMERCS_IOW24:
367 	case USB_DEVICE_ID_CODEMERCS_IOWPV1:
368 	case USB_DEVICE_ID_CODEMERCS_IOWPV2:
369 	case USB_DEVICE_ID_CODEMERCS_IOW40:
370 		/* IOW24 and IOW40 use a synchronous call */
371 		buf = kmalloc(count, GFP_KERNEL);
372 		if (!buf) {
373 			retval = -ENOMEM;
374 			goto exit;
375 		}
376 		if (copy_from_user(buf, user_buffer, count)) {
377 			retval = -EFAULT;
378 			kfree(buf);
379 			goto exit;
380 		}
381 		retval = usb_set_report(dev->interface, 2, 0, buf, count);
382 		kfree(buf);
383 		goto exit;
384 		break;
385 	case USB_DEVICE_ID_CODEMERCS_IOW56:
386 		/* The IOW56 uses asynchronous IO and more urbs */
387 		if (atomic_read(&dev->write_busy) == MAX_WRITES_IN_FLIGHT) {
388 			/* Wait until we are below the limit for submitted urbs */
389 			if (file->f_flags & O_NONBLOCK) {
390 				retval = -EAGAIN;
391 				goto exit;
392 			} else {
393 				retval = wait_event_interruptible(dev->write_wait,
394 								  (!dev->present || (atomic_read (&dev-> write_busy) < MAX_WRITES_IN_FLIGHT)));
395 				if (retval) {
396 					/* we were interrupted by a signal */
397 					retval = -ERESTART;
398 					goto exit;
399 				}
400 				if (!dev->present) {
401 					/* The device was unplugged */
402 					retval = -ENODEV;
403 					goto exit;
404 				}
405 				if (!dev->opened) {
406 					/* We were closed while waiting for an URB */
407 					retval = -ENODEV;
408 					goto exit;
409 				}
410 			}
411 		}
412 		atomic_inc(&dev->write_busy);
413 		int_out_urb = usb_alloc_urb(0, GFP_KERNEL);
414 		if (!int_out_urb) {
415 			retval = -ENOMEM;
416 			dev_dbg(&dev->interface->dev,
417 				"Unable to allocate urb\n");
418 			goto error_no_urb;
419 		}
420 		buf = usb_alloc_coherent(dev->udev, dev->report_size,
421 					 GFP_KERNEL, &int_out_urb->transfer_dma);
422 		if (!buf) {
423 			retval = -ENOMEM;
424 			dev_dbg(&dev->interface->dev,
425 				"Unable to allocate buffer\n");
426 			goto error_no_buffer;
427 		}
428 		usb_fill_int_urb(int_out_urb, dev->udev,
429 				 usb_sndintpipe(dev->udev,
430 						dev->int_out_endpoint->bEndpointAddress),
431 				 buf, dev->report_size,
432 				 iowarrior_write_callback, dev,
433 				 dev->int_out_endpoint->bInterval);
434 		int_out_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
435 		if (copy_from_user(buf, user_buffer, count)) {
436 			retval = -EFAULT;
437 			goto error;
438 		}
439 		retval = usb_submit_urb(int_out_urb, GFP_KERNEL);
440 		if (retval) {
441 			dev_dbg(&dev->interface->dev,
442 				"submit error %d for urb nr.%d\n",
443 				retval, atomic_read(&dev->write_busy));
444 			goto error;
445 		}
446 		/* submit was ok */
447 		retval = count;
448 		usb_free_urb(int_out_urb);
449 		goto exit;
450 		break;
451 	default:
452 		/* what do we have here ? An unsupported Product-ID ? */
453 		dev_err(&dev->interface->dev, "%s - not supported for product=0x%x\n",
454 			__func__, dev->product_id);
455 		retval = -EFAULT;
456 		goto exit;
457 		break;
458 	}
459 error:
460 	usb_free_coherent(dev->udev, dev->report_size, buf,
461 			  int_out_urb->transfer_dma);
462 error_no_buffer:
463 	usb_free_urb(int_out_urb);
464 error_no_urb:
465 	atomic_dec(&dev->write_busy);
466 	wake_up_interruptible(&dev->write_wait);
467 exit:
468 	mutex_unlock(&dev->mutex);
469 	return retval;
470 }
471 
472 /**
473  *	iowarrior_ioctl
474  */
475 static long iowarrior_ioctl(struct file *file, unsigned int cmd,
476 							unsigned long arg)
477 {
478 	struct iowarrior *dev = NULL;
479 	__u8 *buffer;
480 	__u8 __user *user_buffer;
481 	int retval;
482 	int io_res;		/* checks for bytes read/written and copy_to/from_user results */
483 
484 	dev = file->private_data;
485 	if (dev == NULL) {
486 		return -ENODEV;
487 	}
488 
489 	buffer = kzalloc(dev->report_size, GFP_KERNEL);
490 	if (!buffer)
491 		return -ENOMEM;
492 
493 	/* lock this object */
494 	mutex_lock(&iowarrior_mutex);
495 	mutex_lock(&dev->mutex);
496 
497 	/* verify that the device wasn't unplugged */
498 	if (!dev->present) {
499 		retval = -ENODEV;
500 		goto error_out;
501 	}
502 
503 	dev_dbg(&dev->interface->dev, "minor %d, cmd 0x%.4x, arg %ld\n",
504 		dev->minor, cmd, arg);
505 
506 	retval = 0;
507 	io_res = 0;
508 	switch (cmd) {
509 	case IOW_WRITE:
510 		if (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW24 ||
511 		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV1 ||
512 		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV2 ||
513 		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW40) {
514 			user_buffer = (__u8 __user *)arg;
515 			io_res = copy_from_user(buffer, user_buffer,
516 						dev->report_size);
517 			if (io_res) {
518 				retval = -EFAULT;
519 			} else {
520 				io_res = usb_set_report(dev->interface, 2, 0,
521 							buffer,
522 							dev->report_size);
523 				if (io_res < 0)
524 					retval = io_res;
525 			}
526 		} else {
527 			retval = -EINVAL;
528 			dev_err(&dev->interface->dev,
529 				"ioctl 'IOW_WRITE' is not supported for product=0x%x.\n",
530 				dev->product_id);
531 		}
532 		break;
533 	case IOW_READ:
534 		user_buffer = (__u8 __user *)arg;
535 		io_res = usb_get_report(dev->udev,
536 					dev->interface->cur_altsetting, 1, 0,
537 					buffer, dev->report_size);
538 		if (io_res < 0)
539 			retval = io_res;
540 		else {
541 			io_res = copy_to_user(user_buffer, buffer, dev->report_size);
542 			if (io_res)
543 				retval = -EFAULT;
544 		}
545 		break;
546 	case IOW_GETINFO:
547 		{
548 			/* Report available information for the device */
549 			struct iowarrior_info info;
550 			/* needed for power consumption */
551 			struct usb_config_descriptor *cfg_descriptor = &dev->udev->actconfig->desc;
552 
553 			memset(&info, 0, sizeof(info));
554 			/* directly from the descriptor */
555 			info.vendor = le16_to_cpu(dev->udev->descriptor.idVendor);
556 			info.product = dev->product_id;
557 			info.revision = le16_to_cpu(dev->udev->descriptor.bcdDevice);
558 
559 			/* 0==UNKNOWN, 1==LOW(usb1.1) ,2=FULL(usb1.1), 3=HIGH(usb2.0) */
560 			info.speed = le16_to_cpu(dev->udev->speed);
561 			info.if_num = dev->interface->cur_altsetting->desc.bInterfaceNumber;
562 			info.report_size = dev->report_size;
563 
564 			/* serial number string has been read earlier 8 chars or empty string */
565 			memcpy(info.serial, dev->chip_serial,
566 			       sizeof(dev->chip_serial));
567 			if (cfg_descriptor == NULL) {
568 				info.power = -1;	/* no information available */
569 			} else {
570 				/* the MaxPower is stored in units of 2mA to make it fit into a byte-value */
571 				info.power = cfg_descriptor->bMaxPower * 2;
572 			}
573 			io_res = copy_to_user((struct iowarrior_info __user *)arg, &info,
574 					 sizeof(struct iowarrior_info));
575 			if (io_res)
576 				retval = -EFAULT;
577 			break;
578 		}
579 	default:
580 		/* return that we did not understand this ioctl call */
581 		retval = -ENOTTY;
582 		break;
583 	}
584 error_out:
585 	/* unlock the device */
586 	mutex_unlock(&dev->mutex);
587 	mutex_unlock(&iowarrior_mutex);
588 	kfree(buffer);
589 	return retval;
590 }
591 
592 /**
593  *	iowarrior_open
594  */
595 static int iowarrior_open(struct inode *inode, struct file *file)
596 {
597 	struct iowarrior *dev = NULL;
598 	struct usb_interface *interface;
599 	int subminor;
600 	int retval = 0;
601 
602 	mutex_lock(&iowarrior_mutex);
603 	subminor = iminor(inode);
604 
605 	interface = usb_find_interface(&iowarrior_driver, subminor);
606 	if (!interface) {
607 		mutex_unlock(&iowarrior_mutex);
608 		printk(KERN_ERR "%s - error, can't find device for minor %d\n",
609 		       __func__, subminor);
610 		return -ENODEV;
611 	}
612 
613 	mutex_lock(&iowarrior_open_disc_lock);
614 	dev = usb_get_intfdata(interface);
615 	if (!dev) {
616 		mutex_unlock(&iowarrior_open_disc_lock);
617 		mutex_unlock(&iowarrior_mutex);
618 		return -ENODEV;
619 	}
620 
621 	mutex_lock(&dev->mutex);
622 	mutex_unlock(&iowarrior_open_disc_lock);
623 
624 	/* Only one process can open each device, no sharing. */
625 	if (dev->opened) {
626 		retval = -EBUSY;
627 		goto out;
628 	}
629 
630 	/* setup interrupt handler for receiving values */
631 	if ((retval = usb_submit_urb(dev->int_in_urb, GFP_KERNEL)) < 0) {
632 		dev_err(&interface->dev, "Error %d while submitting URB\n", retval);
633 		retval = -EFAULT;
634 		goto out;
635 	}
636 	/* increment our usage count for the driver */
637 	++dev->opened;
638 	/* save our object in the file's private structure */
639 	file->private_data = dev;
640 	retval = 0;
641 
642 out:
643 	mutex_unlock(&dev->mutex);
644 	mutex_unlock(&iowarrior_mutex);
645 	return retval;
646 }
647 
648 /**
649  *	iowarrior_release
650  */
651 static int iowarrior_release(struct inode *inode, struct file *file)
652 {
653 	struct iowarrior *dev;
654 	int retval = 0;
655 
656 	dev = file->private_data;
657 	if (dev == NULL) {
658 		return -ENODEV;
659 	}
660 
661 	dev_dbg(&dev->interface->dev, "minor %d\n", dev->minor);
662 
663 	/* lock our device */
664 	mutex_lock(&dev->mutex);
665 
666 	if (dev->opened <= 0) {
667 		retval = -ENODEV;	/* close called more than once */
668 		mutex_unlock(&dev->mutex);
669 	} else {
670 		dev->opened = 0;	/* we're closing now */
671 		retval = 0;
672 		if (dev->present) {
673 			/*
674 			   The device is still connected so we only shutdown
675 			   pending read-/write-ops.
676 			 */
677 			usb_kill_urb(dev->int_in_urb);
678 			wake_up_interruptible(&dev->read_wait);
679 			wake_up_interruptible(&dev->write_wait);
680 			mutex_unlock(&dev->mutex);
681 		} else {
682 			/* The device was unplugged, cleanup resources */
683 			mutex_unlock(&dev->mutex);
684 			iowarrior_delete(dev);
685 		}
686 	}
687 	return retval;
688 }
689 
690 static unsigned iowarrior_poll(struct file *file, poll_table * wait)
691 {
692 	struct iowarrior *dev = file->private_data;
693 	unsigned int mask = 0;
694 
695 	if (!dev->present)
696 		return POLLERR | POLLHUP;
697 
698 	poll_wait(file, &dev->read_wait, wait);
699 	poll_wait(file, &dev->write_wait, wait);
700 
701 	if (!dev->present)
702 		return POLLERR | POLLHUP;
703 
704 	if (read_index(dev) != -1)
705 		mask |= POLLIN | POLLRDNORM;
706 
707 	if (atomic_read(&dev->write_busy) < MAX_WRITES_IN_FLIGHT)
708 		mask |= POLLOUT | POLLWRNORM;
709 	return mask;
710 }
711 
712 /*
713  * File operations needed when we register this driver.
714  * This assumes that this driver NEEDS file operations,
715  * of course, which means that the driver is expected
716  * to have a node in the /dev directory. If the USB
717  * device were for a network interface then the driver
718  * would use "struct net_driver" instead, and a serial
719  * device would use "struct tty_driver".
720  */
721 static const struct file_operations iowarrior_fops = {
722 	.owner = THIS_MODULE,
723 	.write = iowarrior_write,
724 	.read = iowarrior_read,
725 	.unlocked_ioctl = iowarrior_ioctl,
726 	.open = iowarrior_open,
727 	.release = iowarrior_release,
728 	.poll = iowarrior_poll,
729 	.llseek = noop_llseek,
730 };
731 
732 static char *iowarrior_devnode(struct device *dev, umode_t *mode)
733 {
734 	return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
735 }
736 
737 /*
738  * usb class driver info in order to get a minor number from the usb core,
739  * and to have the device registered with devfs and the driver core
740  */
741 static struct usb_class_driver iowarrior_class = {
742 	.name = "iowarrior%d",
743 	.devnode = iowarrior_devnode,
744 	.fops = &iowarrior_fops,
745 	.minor_base = IOWARRIOR_MINOR_BASE,
746 };
747 
748 /*---------------------------------*/
749 /*  probe and disconnect functions */
750 /*---------------------------------*/
751 /**
752  *	iowarrior_probe
753  *
754  *	Called by the usb core when a new device is connected that it thinks
755  *	this driver might be interested in.
756  */
757 static int iowarrior_probe(struct usb_interface *interface,
758 			   const struct usb_device_id *id)
759 {
760 	struct usb_device *udev = interface_to_usbdev(interface);
761 	struct iowarrior *dev = NULL;
762 	struct usb_host_interface *iface_desc;
763 	struct usb_endpoint_descriptor *endpoint;
764 	int i;
765 	int retval = -ENOMEM;
766 
767 	/* allocate memory for our device state and initialize it */
768 	dev = kzalloc(sizeof(struct iowarrior), GFP_KERNEL);
769 	if (dev == NULL) {
770 		dev_err(&interface->dev, "Out of memory\n");
771 		return retval;
772 	}
773 
774 	mutex_init(&dev->mutex);
775 
776 	atomic_set(&dev->intr_idx, 0);
777 	atomic_set(&dev->read_idx, 0);
778 	spin_lock_init(&dev->intr_idx_lock);
779 	atomic_set(&dev->overflow_flag, 0);
780 	init_waitqueue_head(&dev->read_wait);
781 	atomic_set(&dev->write_busy, 0);
782 	init_waitqueue_head(&dev->write_wait);
783 
784 	dev->udev = udev;
785 	dev->interface = interface;
786 
787 	iface_desc = interface->cur_altsetting;
788 	dev->product_id = le16_to_cpu(udev->descriptor.idProduct);
789 
790 	if (iface_desc->desc.bNumEndpoints < 1) {
791 		dev_err(&interface->dev, "Invalid number of endpoints\n");
792 		retval = -EINVAL;
793 		goto error;
794 	}
795 
796 	/* set up the endpoint information */
797 	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
798 		endpoint = &iface_desc->endpoint[i].desc;
799 
800 		if (usb_endpoint_is_int_in(endpoint))
801 			dev->int_in_endpoint = endpoint;
802 		if (usb_endpoint_is_int_out(endpoint))
803 			/* this one will match for the IOWarrior56 only */
804 			dev->int_out_endpoint = endpoint;
805 	}
806 	/* we have to check the report_size often, so remember it in the endianness suitable for our machine */
807 	dev->report_size = usb_endpoint_maxp(dev->int_in_endpoint);
808 	if ((dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) &&
809 	    (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW56))
810 		/* IOWarrior56 has wMaxPacketSize different from report size */
811 		dev->report_size = 7;
812 
813 	/* create the urb and buffer for reading */
814 	dev->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);
815 	if (!dev->int_in_urb) {
816 		dev_err(&interface->dev, "Couldn't allocate interrupt_in_urb\n");
817 		goto error;
818 	}
819 	dev->int_in_buffer = kmalloc(dev->report_size, GFP_KERNEL);
820 	if (!dev->int_in_buffer) {
821 		dev_err(&interface->dev, "Couldn't allocate int_in_buffer\n");
822 		goto error;
823 	}
824 	usb_fill_int_urb(dev->int_in_urb, dev->udev,
825 			 usb_rcvintpipe(dev->udev,
826 					dev->int_in_endpoint->bEndpointAddress),
827 			 dev->int_in_buffer, dev->report_size,
828 			 iowarrior_callback, dev,
829 			 dev->int_in_endpoint->bInterval);
830 	/* create an internal buffer for interrupt data from the device */
831 	dev->read_queue =
832 	    kmalloc(((dev->report_size + 1) * MAX_INTERRUPT_BUFFER),
833 		    GFP_KERNEL);
834 	if (!dev->read_queue) {
835 		dev_err(&interface->dev, "Couldn't allocate read_queue\n");
836 		goto error;
837 	}
838 	/* Get the serial-number of the chip */
839 	memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
840 	usb_string(udev, udev->descriptor.iSerialNumber, dev->chip_serial,
841 		   sizeof(dev->chip_serial));
842 	if (strlen(dev->chip_serial) != 8)
843 		memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
844 
845 	/* Set the idle timeout to 0, if this is interface 0 */
846 	if (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) {
847 	    usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
848 			    0x0A,
849 			    USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0,
850 			    0, NULL, 0, USB_CTRL_SET_TIMEOUT);
851 	}
852 	/* allow device read and ioctl */
853 	dev->present = 1;
854 
855 	/* we can register the device now, as it is ready */
856 	usb_set_intfdata(interface, dev);
857 
858 	retval = usb_register_dev(interface, &iowarrior_class);
859 	if (retval) {
860 		/* something prevented us from registering this driver */
861 		dev_err(&interface->dev, "Not able to get a minor for this device.\n");
862 		usb_set_intfdata(interface, NULL);
863 		goto error;
864 	}
865 
866 	dev->minor = interface->minor;
867 
868 	/* let the user know what node this device is now attached to */
869 	dev_info(&interface->dev, "IOWarrior product=0x%x, serial=%s interface=%d "
870 		 "now attached to iowarrior%d\n", dev->product_id, dev->chip_serial,
871 		 iface_desc->desc.bInterfaceNumber, dev->minor - IOWARRIOR_MINOR_BASE);
872 	return retval;
873 
874 error:
875 	iowarrior_delete(dev);
876 	return retval;
877 }
878 
879 /**
880  *	iowarrior_disconnect
881  *
882  *	Called by the usb core when the device is removed from the system.
883  */
884 static void iowarrior_disconnect(struct usb_interface *interface)
885 {
886 	struct iowarrior *dev;
887 	int minor;
888 
889 	dev = usb_get_intfdata(interface);
890 	mutex_lock(&iowarrior_open_disc_lock);
891 	usb_set_intfdata(interface, NULL);
892 
893 	minor = dev->minor;
894 
895 	/* give back our minor */
896 	usb_deregister_dev(interface, &iowarrior_class);
897 
898 	mutex_lock(&dev->mutex);
899 
900 	/* prevent device read, write and ioctl */
901 	dev->present = 0;
902 
903 	mutex_unlock(&dev->mutex);
904 	mutex_unlock(&iowarrior_open_disc_lock);
905 
906 	if (dev->opened) {
907 		/* There is a process that holds a filedescriptor to the device ,
908 		   so we only shutdown read-/write-ops going on.
909 		   Deleting the device is postponed until close() was called.
910 		 */
911 		usb_kill_urb(dev->int_in_urb);
912 		wake_up_interruptible(&dev->read_wait);
913 		wake_up_interruptible(&dev->write_wait);
914 	} else {
915 		/* no process is using the device, cleanup now */
916 		iowarrior_delete(dev);
917 	}
918 
919 	dev_info(&interface->dev, "I/O-Warror #%d now disconnected\n",
920 		 minor - IOWARRIOR_MINOR_BASE);
921 }
922 
923 /* usb specific object needed to register this driver with the usb subsystem */
924 static struct usb_driver iowarrior_driver = {
925 	.name = "iowarrior",
926 	.probe = iowarrior_probe,
927 	.disconnect = iowarrior_disconnect,
928 	.id_table = iowarrior_ids,
929 };
930 
931 module_usb_driver(iowarrior_driver);
932