xref: /linux/drivers/usb/misc/iowarrior.c (revision 8b4a40809e5330c9da5d20107d693d92d73b31dc)
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/init.h>
19 #include <linux/slab.h>
20 #include <linux/sched.h>
21 #include <linux/poll.h>
22 #include <linux/version.h>
23 #include <linux/usb/iowarrior.h>
24 
25 /* Version Information */
26 #define DRIVER_VERSION "v0.4.0"
27 #define DRIVER_AUTHOR "Christian Lucht <lucht@codemercs.com>"
28 #define DRIVER_DESC "USB IO-Warrior driver (Linux 2.6.x)"
29 
30 #define USB_VENDOR_ID_CODEMERCS		1984
31 /* low speed iowarrior */
32 #define USB_DEVICE_ID_CODEMERCS_IOW40	0x1500
33 #define USB_DEVICE_ID_CODEMERCS_IOW24	0x1501
34 #define USB_DEVICE_ID_CODEMERCS_IOWPV1	0x1511
35 #define USB_DEVICE_ID_CODEMERCS_IOWPV2	0x1512
36 /* full speed iowarrior */
37 #define USB_DEVICE_ID_CODEMERCS_IOW56	0x1503
38 
39 /* Get a minor range for your devices from the usb maintainer */
40 #ifdef CONFIG_USB_DYNAMIC_MINORS
41 #define IOWARRIOR_MINOR_BASE	0
42 #else
43 #define IOWARRIOR_MINOR_BASE	208	// SKELETON_MINOR_BASE 192 + 16, not offical yet
44 #endif
45 
46 /* interrupt input queue size */
47 #define MAX_INTERRUPT_BUFFER 16
48 /*
49    maximum number of urbs that are submitted for writes at the same time,
50    this applies to the IOWarrior56 only!
51    IOWarrior24 and IOWarrior40 use synchronous usb_control_msg calls.
52 */
53 #define MAX_WRITES_IN_FLIGHT 4
54 
55 /* Use our own dbg macro */
56 #undef dbg
57 #define dbg( format, arg... ) do { if( debug ) printk( KERN_DEBUG __FILE__ ": " format "\n" , ## arg ); } while ( 0 )
58 
59 MODULE_AUTHOR(DRIVER_AUTHOR);
60 MODULE_DESCRIPTION(DRIVER_DESC);
61 MODULE_LICENSE("GPL");
62 
63 /* Module parameters */
64 static int debug = 0;
65 module_param(debug, bool, 0644);
66 MODULE_PARM_DESC(debug, "debug=1 enables debugging messages");
67 
68 static struct usb_driver iowarrior_driver;
69 
70 /*--------------*/
71 /*     data     */
72 /*--------------*/
73 
74 /* Structure to hold all of our device specific stuff */
75 struct iowarrior {
76 	struct mutex mutex;			/* locks this structure */
77 	struct usb_device *udev;		/* save off the usb device pointer */
78 	struct usb_interface *interface;	/* the interface for this device */
79 	unsigned char minor;			/* the starting minor number for this device */
80 	struct usb_endpoint_descriptor *int_out_endpoint;	/* endpoint for reading (needed for IOW56 only) */
81 	struct usb_endpoint_descriptor *int_in_endpoint;	/* endpoint for reading */
82 	struct urb *int_in_urb;		/* the urb for reading data */
83 	unsigned char *int_in_buffer;	/* buffer for data to be read */
84 	unsigned char serial_number;	/* to detect lost packages */
85 	unsigned char *read_queue;	/* size is MAX_INTERRUPT_BUFFER * packet size */
86 	wait_queue_head_t read_wait;
87 	wait_queue_head_t write_wait;	/* wait-queue for writing to the device */
88 	atomic_t write_busy;		/* number of write-urbs submitted */
89 	atomic_t read_idx;
90 	atomic_t intr_idx;
91 	spinlock_t intr_idx_lock;	/* protects intr_idx */
92 	atomic_t overflow_flag;		/* signals an index 'rollover' */
93 	int present;			/* this is 1 as long as the device is connected */
94 	int opened;			/* this is 1 if the device is currently open */
95 	char chip_serial[9];		/* the serial number string of the chip connected */
96 	int report_size;		/* number of bytes in a report */
97 	u16 product_id;
98 };
99 
100 /*--------------*/
101 /*    globals   */
102 /*--------------*/
103 
104 /*
105  *  USB spec identifies 5 second timeouts.
106  */
107 #define GET_TIMEOUT 5
108 #define USB_REQ_GET_REPORT  0x01
109 //#if 0
110 static int usb_get_report(struct usb_device *dev,
111 			  struct usb_host_interface *inter, unsigned char type,
112 			  unsigned char id, void *buf, int size)
113 {
114 	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
115 			       USB_REQ_GET_REPORT,
116 			       USB_DIR_IN | USB_TYPE_CLASS |
117 			       USB_RECIP_INTERFACE, (type << 8) + id,
118 			       inter->desc.bInterfaceNumber, buf, size,
119 			       GET_TIMEOUT*HZ);
120 }
121 //#endif
122 
123 #define USB_REQ_SET_REPORT 0x09
124 
125 static int usb_set_report(struct usb_interface *intf, unsigned char type,
126 			  unsigned char id, void *buf, int size)
127 {
128 	return usb_control_msg(interface_to_usbdev(intf),
129 			       usb_sndctrlpipe(interface_to_usbdev(intf), 0),
130 			       USB_REQ_SET_REPORT,
131 			       USB_TYPE_CLASS | USB_RECIP_INTERFACE,
132 			       (type << 8) + id,
133 			       intf->cur_altsetting->desc.bInterfaceNumber, buf,
134 			       size, HZ);
135 }
136 
137 /*---------------------*/
138 /* driver registration */
139 /*---------------------*/
140 /* table of devices that work with this driver */
141 static struct usb_device_id iowarrior_ids[] = {
142 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW40)},
143 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW24)},
144 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV1)},
145 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV2)},
146 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW56)},
147 	{}			/* Terminating entry */
148 };
149 MODULE_DEVICE_TABLE(usb, iowarrior_ids);
150 
151 /*
152  * USB callback handler for reading data
153  */
154 static void iowarrior_callback(struct urb *urb)
155 {
156 	struct iowarrior *dev = (struct iowarrior *)urb->context;
157 	int intr_idx;
158 	int read_idx;
159 	int aux_idx;
160 	int offset;
161 	int status;
162 
163 	switch (urb->status) {
164 	case 0:
165 		/* success */
166 		break;
167 	case -ECONNRESET:
168 	case -ENOENT:
169 	case -ESHUTDOWN:
170 		return;
171 	default:
172 		goto exit;
173 	}
174 
175 	spin_lock(&dev->intr_idx_lock);
176 	intr_idx = atomic_read(&dev->intr_idx);
177 	/* aux_idx become previous intr_idx */
178 	aux_idx = (intr_idx == 0) ? (MAX_INTERRUPT_BUFFER - 1) : (intr_idx - 1);
179 	read_idx = atomic_read(&dev->read_idx);
180 
181 	/* queue is not empty and it's interface 0 */
182 	if ((intr_idx != read_idx)
183 	    && (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0)) {
184 		/* + 1 for serial number */
185 		offset = aux_idx * (dev->report_size + 1);
186 		if (!memcmp
187 		    (dev->read_queue + offset, urb->transfer_buffer,
188 		     dev->report_size)) {
189 			/* equal values on interface 0 will be ignored */
190 			spin_unlock(&dev->intr_idx_lock);
191 			goto exit;
192 		}
193 	}
194 
195 	/* aux_idx become next intr_idx */
196 	aux_idx = (intr_idx == (MAX_INTERRUPT_BUFFER - 1)) ? 0 : (intr_idx + 1);
197 	if (read_idx == aux_idx) {
198 		/* queue full, dropping oldest input */
199 		read_idx = (++read_idx == MAX_INTERRUPT_BUFFER) ? 0 : read_idx;
200 		atomic_set(&dev->read_idx, read_idx);
201 		atomic_set(&dev->overflow_flag, 1);
202 	}
203 
204 	/* +1 for serial number */
205 	offset = intr_idx * (dev->report_size + 1);
206 	memcpy(dev->read_queue + offset, urb->transfer_buffer,
207 	       dev->report_size);
208 	*(dev->read_queue + offset + (dev->report_size)) = dev->serial_number++;
209 
210 	atomic_set(&dev->intr_idx, aux_idx);
211 	spin_unlock(&dev->intr_idx_lock);
212 	/* tell the blocking read about the new data */
213 	wake_up_interruptible(&dev->read_wait);
214 
215 exit:
216 	status = usb_submit_urb(urb, GFP_ATOMIC);
217 	if (status)
218 		dev_err(&dev->interface->dev, "%s - usb_submit_urb failed with result %d",
219 			__FUNCTION__, status);
220 
221 }
222 
223 /*
224  * USB Callback handler for write-ops
225  */
226 static void iowarrior_write_callback(struct urb *urb)
227 {
228 	struct iowarrior *dev;
229 	dev = (struct iowarrior *)urb->context;
230 	/* sync/async unlink faults aren't errors */
231 	if (urb->status &&
232 	    !(urb->status == -ENOENT ||
233 	      urb->status == -ECONNRESET || urb->status == -ESHUTDOWN)) {
234 		dbg("%s - nonzero write bulk status received: %d",
235 		    __func__, urb->status);
236 	}
237 	/* free up our allocated buffer */
238 	usb_buffer_free(urb->dev, urb->transfer_buffer_length,
239 			urb->transfer_buffer, urb->transfer_dma);
240 	/* tell a waiting writer the interrupt-out-pipe is available again */
241 	atomic_dec(&dev->write_busy);
242 	wake_up_interruptible(&dev->write_wait);
243 }
244 
245 /**
246  *	iowarrior_delete
247  */
248 static inline void iowarrior_delete(struct iowarrior *dev)
249 {
250 	dbg("%s - minor %d", __func__, dev->minor);
251 	kfree(dev->int_in_buffer);
252 	usb_free_urb(dev->int_in_urb);
253 	kfree(dev->read_queue);
254 	kfree(dev);
255 }
256 
257 /*---------------------*/
258 /* fops implementation */
259 /*---------------------*/
260 
261 static int read_index(struct iowarrior *dev)
262 {
263 	int intr_idx, read_idx;
264 
265 	read_idx = atomic_read(&dev->read_idx);
266 	intr_idx = atomic_read(&dev->intr_idx);
267 
268 	return (read_idx == intr_idx ? -1 : read_idx);
269 }
270 
271 /**
272  *  iowarrior_read
273  */
274 static ssize_t iowarrior_read(struct file *file, char __user *buffer,
275 			      size_t count, loff_t *ppos)
276 {
277 	struct iowarrior *dev;
278 	int read_idx;
279 	int offset;
280 
281 	dev = (struct iowarrior *)file->private_data;
282 
283 	/* verify that the device wasn't unplugged */
284 	if (dev == NULL || !dev->present)
285 		return -ENODEV;
286 
287 	dbg("%s - minor %d, count = %zd", __func__, dev->minor, count);
288 
289 	/* read count must be packet size (+ time stamp) */
290 	if ((count != dev->report_size)
291 	    && (count != (dev->report_size + 1)))
292 		return -EINVAL;
293 
294 	/* repeat until no buffer overrun in callback handler occur */
295 	do {
296 		atomic_set(&dev->overflow_flag, 0);
297 		if ((read_idx = read_index(dev)) == -1) {
298 			/* queue emty */
299 			if (file->f_flags & O_NONBLOCK)
300 				return -EAGAIN;
301 			else {
302 				//next line will return when there is either new data, or the device is unplugged
303 				int r = wait_event_interruptible(dev->read_wait,
304 								 (!dev->present
305 								  || (read_idx =
306 								      read_index
307 								      (dev)) !=
308 								  -1));
309 				if (r) {
310 					//we were interrupted by a signal
311 					return -ERESTART;
312 				}
313 				if (!dev->present) {
314 					//The device was unplugged
315 					return -ENODEV;
316 				}
317 				if (read_idx == -1) {
318 					// Can this happen ???
319 					return 0;
320 				}
321 			}
322 		}
323 
324 		offset = read_idx * (dev->report_size + 1);
325 		if (copy_to_user(buffer, dev->read_queue + offset, count)) {
326 			return -EFAULT;
327 		}
328 	} while (atomic_read(&dev->overflow_flag));
329 
330 	read_idx = ++read_idx == MAX_INTERRUPT_BUFFER ? 0 : read_idx;
331 	atomic_set(&dev->read_idx, read_idx);
332 	return count;
333 }
334 
335 /*
336  * iowarrior_write
337  */
338 static ssize_t iowarrior_write(struct file *file,
339 			       const char __user *user_buffer,
340 			       size_t count, loff_t *ppos)
341 {
342 	struct iowarrior *dev;
343 	int retval = 0;
344 	char *buf = NULL;	/* for IOW24 and IOW56 we need a buffer */
345 	struct urb *int_out_urb = NULL;
346 
347 	dev = (struct iowarrior *)file->private_data;
348 
349 	mutex_lock(&dev->mutex);
350 	/* verify that the device wasn't unplugged */
351 	if (dev == NULL || !dev->present) {
352 		retval = -ENODEV;
353 		goto exit;
354 	}
355 	dbg("%s - minor %d, count = %zd", __func__, dev->minor, count);
356 	/* if count is 0 we're already done */
357 	if (count == 0) {
358 		retval = 0;
359 		goto exit;
360 	}
361 	/* We only accept full reports */
362 	if (count != dev->report_size) {
363 		retval = -EINVAL;
364 		goto exit;
365 	}
366 	switch (dev->product_id) {
367 	case USB_DEVICE_ID_CODEMERCS_IOW24:
368 	case USB_DEVICE_ID_CODEMERCS_IOWPV1:
369 	case USB_DEVICE_ID_CODEMERCS_IOWPV2:
370 	case USB_DEVICE_ID_CODEMERCS_IOW40:
371 		/* IOW24 and IOW40 use a synchronous call */
372 		buf = kmalloc(8, GFP_KERNEL);	/* 8 bytes are enough for both products */
373 		if (!buf) {
374 			retval = -ENOMEM;
375 			goto exit;
376 		}
377 		if (copy_from_user(buf, user_buffer, count)) {
378 			retval = -EFAULT;
379 			kfree(buf);
380 			goto exit;
381 		}
382 		retval = usb_set_report(dev->interface, 2, 0, buf, count);
383 		kfree(buf);
384 		goto exit;
385 		break;
386 	case USB_DEVICE_ID_CODEMERCS_IOW56:
387 		/* The IOW56 uses asynchronous IO and more urbs */
388 		if (atomic_read(&dev->write_busy) == MAX_WRITES_IN_FLIGHT) {
389 			/* Wait until we are below the limit for submitted urbs */
390 			if (file->f_flags & O_NONBLOCK) {
391 				retval = -EAGAIN;
392 				goto exit;
393 			} else {
394 				retval = wait_event_interruptible(dev->write_wait,
395 								  (!dev->present || (atomic_read (&dev-> write_busy) < MAX_WRITES_IN_FLIGHT)));
396 				if (retval) {
397 					/* we were interrupted by a signal */
398 					retval = -ERESTART;
399 					goto exit;
400 				}
401 				if (!dev->present) {
402 					/* The device was unplugged */
403 					retval = -ENODEV;
404 					goto exit;
405 				}
406 				if (!dev->opened) {
407 					/* We were closed while waiting for an URB */
408 					retval = -ENODEV;
409 					goto exit;
410 				}
411 			}
412 		}
413 		atomic_inc(&dev->write_busy);
414 		int_out_urb = usb_alloc_urb(0, GFP_KERNEL);
415 		if (!int_out_urb) {
416 			retval = -ENOMEM;
417 			dbg("%s Unable to allocate urb ", __func__);
418 			goto error_no_urb;
419 		}
420 		buf = usb_buffer_alloc(dev->udev, dev->report_size,
421 				       GFP_KERNEL, &int_out_urb->transfer_dma);
422 		if (!buf) {
423 			retval = -ENOMEM;
424 			dbg("%s Unable to allocate buffer ", __func__);
425 			goto error_no_buffer;
426 		}
427 		usb_fill_int_urb(int_out_urb, dev->udev,
428 				 usb_sndintpipe(dev->udev,
429 						dev->int_out_endpoint->bEndpointAddress),
430 				 buf, dev->report_size,
431 				 iowarrior_write_callback, dev,
432 				 dev->int_out_endpoint->bInterval);
433 		int_out_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
434 		if (copy_from_user(buf, user_buffer, count)) {
435 			retval = -EFAULT;
436 			goto error;
437 		}
438 		retval = usb_submit_urb(int_out_urb, GFP_KERNEL);
439 		if (retval) {
440 			dbg("%s submit error %d for urb nr.%d", __func__,
441 			    retval, atomic_read(&dev->write_busy));
442 			goto error;
443 		}
444 		/* submit was ok */
445 		retval = count;
446 		usb_free_urb(int_out_urb);
447 		goto exit;
448 		break;
449 	default:
450 		/* what do we have here ? An unsupported Product-ID ? */
451 		dev_err(&dev->interface->dev, "%s - not supported for product=0x%x",
452 			__FUNCTION__, dev->product_id);
453 		retval = -EFAULT;
454 		goto exit;
455 		break;
456 	}
457 error:
458 	usb_buffer_free(dev->udev, dev->report_size, buf,
459 			int_out_urb->transfer_dma);
460 error_no_buffer:
461 	usb_free_urb(int_out_urb);
462 error_no_urb:
463 	atomic_dec(&dev->write_busy);
464 	wake_up_interruptible(&dev->write_wait);
465 exit:
466 	mutex_unlock(&dev->mutex);
467 	return retval;
468 }
469 
470 /**
471  *	iowarrior_ioctl
472  */
473 static int iowarrior_ioctl(struct inode *inode, struct file *file,
474 			   unsigned int cmd, unsigned long arg)
475 {
476 	struct iowarrior *dev = NULL;
477 	__u8 *buffer;
478 	__u8 __user *user_buffer;
479 	int retval;
480 	int io_res;		/* checks for bytes read/written and copy_to/from_user results */
481 
482 	dev = (struct iowarrior *)file->private_data;
483 	if (dev == NULL) {
484 		return -ENODEV;
485 	}
486 
487 	buffer = kzalloc(dev->report_size, GFP_KERNEL);
488 	if (!buffer)
489 		return -ENOMEM;
490 
491 	/* lock this object */
492 	mutex_lock(&dev->mutex);
493 
494 	/* verify that the device wasn't unplugged */
495 	if (!dev->present) {
496 		retval = -ENODEV;
497 		goto error_out;
498 	}
499 
500 	dbg("%s - minor %d, cmd 0x%.4x, arg %ld", __func__, dev->minor, cmd,
501 	    arg);
502 
503 	retval = 0;
504 	io_res = 0;
505 	switch (cmd) {
506 	case IOW_WRITE:
507 		if (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW24 ||
508 		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV1 ||
509 		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV2 ||
510 		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW40) {
511 			user_buffer = (__u8 __user *)arg;
512 			io_res = copy_from_user(buffer, user_buffer,
513 						dev->report_size);
514 			if (io_res) {
515 				retval = -EFAULT;
516 			} else {
517 				io_res = usb_set_report(dev->interface, 2, 0,
518 							buffer,
519 							dev->report_size);
520 				if (io_res < 0)
521 					retval = io_res;
522 			}
523 		} else {
524 			retval = -EINVAL;
525 			dev_err(&dev->interface->dev,
526 				"ioctl 'IOW_WRITE' is not supported for product=0x%x.",
527 				dev->product_id);
528 		}
529 		break;
530 	case IOW_READ:
531 		user_buffer = (__u8 __user *)arg;
532 		io_res = usb_get_report(dev->udev,
533 					dev->interface->cur_altsetting, 1, 0,
534 					buffer, dev->report_size);
535 		if (io_res < 0)
536 			retval = io_res;
537 		else {
538 			io_res = copy_to_user(user_buffer, buffer, dev->report_size);
539 			if (io_res < 0)
540 				retval = -EFAULT;
541 		}
542 		break;
543 	case IOW_GETINFO:
544 		{
545 			/* Report available information for the device */
546 			struct iowarrior_info info;
547 			/* needed for power consumption */
548 			struct usb_config_descriptor *cfg_descriptor = &dev->udev->actconfig->desc;
549 
550 			/* directly from the descriptor */
551 			info.vendor = le16_to_cpu(dev->udev->descriptor.idVendor);
552 			info.product = dev->product_id;
553 			info.revision = le16_to_cpu(dev->udev->descriptor.bcdDevice);
554 
555 			/* 0==UNKNOWN, 1==LOW(usb1.1) ,2=FULL(usb1.1), 3=HIGH(usb2.0) */
556 			info.speed = le16_to_cpu(dev->udev->speed);
557 			info.if_num = dev->interface->cur_altsetting->desc.bInterfaceNumber;
558 			info.report_size = dev->report_size;
559 
560 			/* serial number string has been read earlier 8 chars or empty string */
561 			memcpy(info.serial, dev->chip_serial,
562 			       sizeof(dev->chip_serial));
563 			if (cfg_descriptor == NULL) {
564 				info.power = -1;	/* no information available */
565 			} else {
566 				/* the MaxPower is stored in units of 2mA to make it fit into a byte-value */
567 				info.power = cfg_descriptor->bMaxPower * 2;
568 			}
569 			io_res = copy_to_user((struct iowarrior_info __user *)arg, &info,
570 					 sizeof(struct iowarrior_info));
571 			if (io_res < 0)
572 				retval = -EFAULT;
573 			break;
574 		}
575 	default:
576 		/* return that we did not understand this ioctl call */
577 		retval = -ENOTTY;
578 		break;
579 	}
580 error_out:
581 	/* unlock the device */
582 	mutex_unlock(&dev->mutex);
583 	kfree(buffer);
584 	return retval;
585 }
586 
587 /**
588  *	iowarrior_open
589  */
590 static int iowarrior_open(struct inode *inode, struct file *file)
591 {
592 	struct iowarrior *dev = NULL;
593 	struct usb_interface *interface;
594 	int subminor;
595 	int retval = 0;
596 
597 	dbg("%s", __func__);
598 
599 	subminor = iminor(inode);
600 
601 	interface = usb_find_interface(&iowarrior_driver, subminor);
602 	if (!interface) {
603 		err("%s - error, can't find device for minor %d", __FUNCTION__,
604 		    subminor);
605 		return -ENODEV;
606 	}
607 
608 	dev = usb_get_intfdata(interface);
609 	if (!dev)
610 		return -ENODEV;
611 
612 	mutex_lock(&dev->mutex);
613 
614 	/* Only one process can open each device, no sharing. */
615 	if (dev->opened) {
616 		retval = -EBUSY;
617 		goto out;
618 	}
619 
620 	/* setup interrupt handler for receiving values */
621 	if ((retval = usb_submit_urb(dev->int_in_urb, GFP_KERNEL)) < 0) {
622 		dev_err(&interface->dev, "Error %d while submitting URB\n", retval);
623 		retval = -EFAULT;
624 		goto out;
625 	}
626 	/* increment our usage count for the driver */
627 	++dev->opened;
628 	/* save our object in the file's private structure */
629 	file->private_data = dev;
630 	retval = 0;
631 
632 out:
633 	mutex_unlock(&dev->mutex);
634 	return retval;
635 }
636 
637 /**
638  *	iowarrior_release
639  */
640 static int iowarrior_release(struct inode *inode, struct file *file)
641 {
642 	struct iowarrior *dev;
643 	int retval = 0;
644 
645 	dev = (struct iowarrior *)file->private_data;
646 	if (dev == NULL) {
647 		return -ENODEV;
648 	}
649 
650 	dbg("%s - minor %d", __func__, dev->minor);
651 
652 	/* lock our device */
653 	mutex_lock(&dev->mutex);
654 
655 	if (dev->opened <= 0) {
656 		retval = -ENODEV;	/* close called more than once */
657 		mutex_unlock(&dev->mutex);
658 	} else {
659 		dev->opened = 0;	/* we're closeing now */
660 		retval = 0;
661 		if (dev->present) {
662 			/*
663 			   The device is still connected so we only shutdown
664 			   pending read-/write-ops.
665 			 */
666 			usb_kill_urb(dev->int_in_urb);
667 			wake_up_interruptible(&dev->read_wait);
668 			wake_up_interruptible(&dev->write_wait);
669 			mutex_unlock(&dev->mutex);
670 		} else {
671 			/* The device was unplugged, cleanup resources */
672 			mutex_unlock(&dev->mutex);
673 			iowarrior_delete(dev);
674 		}
675 	}
676 	return retval;
677 }
678 
679 static unsigned iowarrior_poll(struct file *file, poll_table * wait)
680 {
681 	struct iowarrior *dev = file->private_data;
682 	unsigned int mask = 0;
683 
684 	if (!dev->present)
685 		return POLLERR | POLLHUP;
686 
687 	poll_wait(file, &dev->read_wait, wait);
688 	poll_wait(file, &dev->write_wait, wait);
689 
690 	if (!dev->present)
691 		return POLLERR | POLLHUP;
692 
693 	if (read_index(dev) != -1)
694 		mask |= POLLIN | POLLRDNORM;
695 
696 	if (atomic_read(&dev->write_busy) < MAX_WRITES_IN_FLIGHT)
697 		mask |= POLLOUT | POLLWRNORM;
698 	return mask;
699 }
700 
701 /*
702  * File operations needed when we register this driver.
703  * This assumes that this driver NEEDS file operations,
704  * of course, which means that the driver is expected
705  * to have a node in the /dev directory. If the USB
706  * device were for a network interface then the driver
707  * would use "struct net_driver" instead, and a serial
708  * device would use "struct tty_driver".
709  */
710 static struct file_operations iowarrior_fops = {
711 	.owner = THIS_MODULE,
712 	.write = iowarrior_write,
713 	.read = iowarrior_read,
714 	.ioctl = iowarrior_ioctl,
715 	.open = iowarrior_open,
716 	.release = iowarrior_release,
717 	.poll = iowarrior_poll,
718 };
719 
720 /*
721  * usb class driver info in order to get a minor number from the usb core,
722  * and to have the device registered with devfs and the driver core
723  */
724 static struct usb_class_driver iowarrior_class = {
725 	.name = "iowarrior%d",
726 	.fops = &iowarrior_fops,
727 	.minor_base = IOWARRIOR_MINOR_BASE,
728 };
729 
730 /*---------------------------------*/
731 /*  probe and disconnect functions */
732 /*---------------------------------*/
733 /**
734  *	iowarrior_probe
735  *
736  *	Called by the usb core when a new device is connected that it thinks
737  *	this driver might be interested in.
738  */
739 static int iowarrior_probe(struct usb_interface *interface,
740 			   const struct usb_device_id *id)
741 {
742 	struct usb_device *udev = interface_to_usbdev(interface);
743 	struct iowarrior *dev = NULL;
744 	struct usb_host_interface *iface_desc;
745 	struct usb_endpoint_descriptor *endpoint;
746 	int i;
747 	int retval = -ENOMEM;
748 
749 	/* allocate memory for our device state and intialize it */
750 	dev = kzalloc(sizeof(struct iowarrior), GFP_KERNEL);
751 	if (dev == NULL) {
752 		dev_err(&interface->dev, "Out of memory");
753 		return retval;
754 	}
755 
756 	mutex_init(&dev->mutex);
757 
758 	atomic_set(&dev->intr_idx, 0);
759 	atomic_set(&dev->read_idx, 0);
760 	spin_lock_init(&dev->intr_idx_lock);
761 	atomic_set(&dev->overflow_flag, 0);
762 	init_waitqueue_head(&dev->read_wait);
763 	atomic_set(&dev->write_busy, 0);
764 	init_waitqueue_head(&dev->write_wait);
765 
766 	dev->udev = udev;
767 	dev->interface = interface;
768 
769 	iface_desc = interface->cur_altsetting;
770 	dev->product_id = le16_to_cpu(udev->descriptor.idProduct);
771 
772 	/* set up the endpoint information */
773 	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
774 		endpoint = &iface_desc->endpoint[i].desc;
775 
776 		if (usb_endpoint_is_int_in(endpoint))
777 			dev->int_in_endpoint = endpoint;
778 		if (usb_endpoint_is_int_out(endpoint))
779 			/* this one will match for the IOWarrior56 only */
780 			dev->int_out_endpoint = endpoint;
781 	}
782 	/* we have to check the report_size often, so remember it in the endianess suitable for our machine */
783 	dev->report_size = le16_to_cpu(dev->int_in_endpoint->wMaxPacketSize);
784 	if ((dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) &&
785 	    (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW56))
786 		/* IOWarrior56 has wMaxPacketSize different from report size */
787 		dev->report_size = 7;
788 
789 	/* create the urb and buffer for reading */
790 	dev->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);
791 	if (!dev->int_in_urb) {
792 		dev_err(&interface->dev, "Couldn't allocate interrupt_in_urb\n");
793 		goto error;
794 	}
795 	dev->int_in_buffer = kmalloc(dev->report_size, GFP_KERNEL);
796 	if (!dev->int_in_buffer) {
797 		dev_err(&interface->dev, "Couldn't allocate int_in_buffer\n");
798 		goto error;
799 	}
800 	usb_fill_int_urb(dev->int_in_urb, dev->udev,
801 			 usb_rcvintpipe(dev->udev,
802 					dev->int_in_endpoint->bEndpointAddress),
803 			 dev->int_in_buffer, dev->report_size,
804 			 iowarrior_callback, dev,
805 			 dev->int_in_endpoint->bInterval);
806 	/* create an internal buffer for interrupt data from the device */
807 	dev->read_queue =
808 	    kmalloc(((dev->report_size + 1) * MAX_INTERRUPT_BUFFER),
809 		    GFP_KERNEL);
810 	if (!dev->read_queue) {
811 		dev_err(&interface->dev, "Couldn't allocate read_queue\n");
812 		goto error;
813 	}
814 	/* Get the serial-number of the chip */
815 	memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
816 	usb_string(udev, udev->descriptor.iSerialNumber, dev->chip_serial,
817 		   sizeof(dev->chip_serial));
818 	if (strlen(dev->chip_serial) != 8)
819 		memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
820 
821 	/* Set the idle timeout to 0, if this is interface 0 */
822 	if (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) {
823 	    usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
824 			    0x0A,
825 			    USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0,
826 			    0, NULL, 0, USB_CTRL_SET_TIMEOUT);
827 	}
828 	/* allow device read and ioctl */
829 	dev->present = 1;
830 
831 	/* we can register the device now, as it is ready */
832 	usb_set_intfdata(interface, dev);
833 
834 	retval = usb_register_dev(interface, &iowarrior_class);
835 	if (retval) {
836 		/* something prevented us from registering this driver */
837 		dev_err(&interface->dev, "Not able to get a minor for this device.\n");
838 		usb_set_intfdata(interface, NULL);
839 		goto error;
840 	}
841 
842 	dev->minor = interface->minor;
843 
844 	/* let the user know what node this device is now attached to */
845 	dev_info(&interface->dev, "IOWarrior product=0x%x, serial=%s interface=%d "
846 		 "now attached to iowarrior%d\n", dev->product_id, dev->chip_serial,
847 		 iface_desc->desc.bInterfaceNumber, dev->minor - IOWARRIOR_MINOR_BASE);
848 	return retval;
849 
850 error:
851 	iowarrior_delete(dev);
852 	return retval;
853 }
854 
855 /**
856  *	iowarrior_disconnect
857  *
858  *	Called by the usb core when the device is removed from the system.
859  */
860 static void iowarrior_disconnect(struct usb_interface *interface)
861 {
862 	struct iowarrior *dev;
863 	int minor;
864 
865 	dev = usb_get_intfdata(interface);
866 	usb_set_intfdata(interface, NULL);
867 
868 	minor = dev->minor;
869 
870 	/* give back our minor */
871 	usb_deregister_dev(interface, &iowarrior_class);
872 
873 	mutex_lock(&dev->mutex);
874 
875 	/* prevent device read, write and ioctl */
876 	dev->present = 0;
877 
878 	mutex_unlock(&dev->mutex);
879 
880 	if (dev->opened) {
881 		/* There is a process that holds a filedescriptor to the device ,
882 		   so we only shutdown read-/write-ops going on.
883 		   Deleting the device is postponed until close() was called.
884 		 */
885 		usb_kill_urb(dev->int_in_urb);
886 		wake_up_interruptible(&dev->read_wait);
887 		wake_up_interruptible(&dev->write_wait);
888 	} else {
889 		/* no process is using the device, cleanup now */
890 		iowarrior_delete(dev);
891 	}
892 
893 	dev_info(&interface->dev, "I/O-Warror #%d now disconnected\n",
894 		 minor - IOWARRIOR_MINOR_BASE);
895 }
896 
897 /* usb specific object needed to register this driver with the usb subsystem */
898 static struct usb_driver iowarrior_driver = {
899 	.name = "iowarrior",
900 	.probe = iowarrior_probe,
901 	.disconnect = iowarrior_disconnect,
902 	.id_table = iowarrior_ids,
903 };
904 
905 static int __init iowarrior_init(void)
906 {
907 	return usb_register(&iowarrior_driver);
908 }
909 
910 static void __exit iowarrior_exit(void)
911 {
912 	usb_deregister(&iowarrior_driver);
913 }
914 
915 module_init(iowarrior_init);
916 module_exit(iowarrior_exit);
917