xref: /openbmc/linux/drivers/usb/misc/iowarrior.c (revision c21b37f6)
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 = urb->status;
162 	int retval;
163 
164 	switch (status) {
165 	case 0:
166 		/* success */
167 		break;
168 	case -ECONNRESET:
169 	case -ENOENT:
170 	case -ESHUTDOWN:
171 		return;
172 	default:
173 		goto exit;
174 	}
175 
176 	spin_lock(&dev->intr_idx_lock);
177 	intr_idx = atomic_read(&dev->intr_idx);
178 	/* aux_idx become previous intr_idx */
179 	aux_idx = (intr_idx == 0) ? (MAX_INTERRUPT_BUFFER - 1) : (intr_idx - 1);
180 	read_idx = atomic_read(&dev->read_idx);
181 
182 	/* queue is not empty and it's interface 0 */
183 	if ((intr_idx != read_idx)
184 	    && (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0)) {
185 		/* + 1 for serial number */
186 		offset = aux_idx * (dev->report_size + 1);
187 		if (!memcmp
188 		    (dev->read_queue + offset, urb->transfer_buffer,
189 		     dev->report_size)) {
190 			/* equal values on interface 0 will be ignored */
191 			spin_unlock(&dev->intr_idx_lock);
192 			goto exit;
193 		}
194 	}
195 
196 	/* aux_idx become next intr_idx */
197 	aux_idx = (intr_idx == (MAX_INTERRUPT_BUFFER - 1)) ? 0 : (intr_idx + 1);
198 	if (read_idx == aux_idx) {
199 		/* queue full, dropping oldest input */
200 		read_idx = (++read_idx == MAX_INTERRUPT_BUFFER) ? 0 : read_idx;
201 		atomic_set(&dev->read_idx, read_idx);
202 		atomic_set(&dev->overflow_flag, 1);
203 	}
204 
205 	/* +1 for serial number */
206 	offset = intr_idx * (dev->report_size + 1);
207 	memcpy(dev->read_queue + offset, urb->transfer_buffer,
208 	       dev->report_size);
209 	*(dev->read_queue + offset + (dev->report_size)) = dev->serial_number++;
210 
211 	atomic_set(&dev->intr_idx, aux_idx);
212 	spin_unlock(&dev->intr_idx_lock);
213 	/* tell the blocking read about the new data */
214 	wake_up_interruptible(&dev->read_wait);
215 
216 exit:
217 	retval = usb_submit_urb(urb, GFP_ATOMIC);
218 	if (retval)
219 		dev_err(&dev->interface->dev, "%s - usb_submit_urb failed with result %d",
220 			__FUNCTION__, retval);
221 
222 }
223 
224 /*
225  * USB Callback handler for write-ops
226  */
227 static void iowarrior_write_callback(struct urb *urb)
228 {
229 	struct iowarrior *dev;
230 	int status = urb->status;
231 
232 	dev = (struct iowarrior *)urb->context;
233 	/* sync/async unlink faults aren't errors */
234 	if (status &&
235 	    !(status == -ENOENT ||
236 	      status == -ECONNRESET || status == -ESHUTDOWN)) {
237 		dbg("%s - nonzero write bulk status received: %d",
238 		    __func__, status);
239 	}
240 	/* free up our allocated buffer */
241 	usb_buffer_free(urb->dev, urb->transfer_buffer_length,
242 			urb->transfer_buffer, urb->transfer_dma);
243 	/* tell a waiting writer the interrupt-out-pipe is available again */
244 	atomic_dec(&dev->write_busy);
245 	wake_up_interruptible(&dev->write_wait);
246 }
247 
248 /**
249  *	iowarrior_delete
250  */
251 static inline void iowarrior_delete(struct iowarrior *dev)
252 {
253 	dbg("%s - minor %d", __func__, dev->minor);
254 	kfree(dev->int_in_buffer);
255 	usb_free_urb(dev->int_in_urb);
256 	kfree(dev->read_queue);
257 	kfree(dev);
258 }
259 
260 /*---------------------*/
261 /* fops implementation */
262 /*---------------------*/
263 
264 static int read_index(struct iowarrior *dev)
265 {
266 	int intr_idx, read_idx;
267 
268 	read_idx = atomic_read(&dev->read_idx);
269 	intr_idx = atomic_read(&dev->intr_idx);
270 
271 	return (read_idx == intr_idx ? -1 : read_idx);
272 }
273 
274 /**
275  *  iowarrior_read
276  */
277 static ssize_t iowarrior_read(struct file *file, char __user *buffer,
278 			      size_t count, loff_t *ppos)
279 {
280 	struct iowarrior *dev;
281 	int read_idx;
282 	int offset;
283 
284 	dev = (struct iowarrior *)file->private_data;
285 
286 	/* verify that the device wasn't unplugged */
287 	if (dev == NULL || !dev->present)
288 		return -ENODEV;
289 
290 	dbg("%s - minor %d, count = %zd", __func__, dev->minor, count);
291 
292 	/* read count must be packet size (+ time stamp) */
293 	if ((count != dev->report_size)
294 	    && (count != (dev->report_size + 1)))
295 		return -EINVAL;
296 
297 	/* repeat until no buffer overrun in callback handler occur */
298 	do {
299 		atomic_set(&dev->overflow_flag, 0);
300 		if ((read_idx = read_index(dev)) == -1) {
301 			/* queue emty */
302 			if (file->f_flags & O_NONBLOCK)
303 				return -EAGAIN;
304 			else {
305 				//next line will return when there is either new data, or the device is unplugged
306 				int r = wait_event_interruptible(dev->read_wait,
307 								 (!dev->present
308 								  || (read_idx =
309 								      read_index
310 								      (dev)) !=
311 								  -1));
312 				if (r) {
313 					//we were interrupted by a signal
314 					return -ERESTART;
315 				}
316 				if (!dev->present) {
317 					//The device was unplugged
318 					return -ENODEV;
319 				}
320 				if (read_idx == -1) {
321 					// Can this happen ???
322 					return 0;
323 				}
324 			}
325 		}
326 
327 		offset = read_idx * (dev->report_size + 1);
328 		if (copy_to_user(buffer, dev->read_queue + offset, count)) {
329 			return -EFAULT;
330 		}
331 	} while (atomic_read(&dev->overflow_flag));
332 
333 	read_idx = ++read_idx == MAX_INTERRUPT_BUFFER ? 0 : read_idx;
334 	atomic_set(&dev->read_idx, read_idx);
335 	return count;
336 }
337 
338 /*
339  * iowarrior_write
340  */
341 static ssize_t iowarrior_write(struct file *file,
342 			       const char __user *user_buffer,
343 			       size_t count, loff_t *ppos)
344 {
345 	struct iowarrior *dev;
346 	int retval = 0;
347 	char *buf = NULL;	/* for IOW24 and IOW56 we need a buffer */
348 	struct urb *int_out_urb = NULL;
349 
350 	dev = (struct iowarrior *)file->private_data;
351 
352 	mutex_lock(&dev->mutex);
353 	/* verify that the device wasn't unplugged */
354 	if (dev == NULL || !dev->present) {
355 		retval = -ENODEV;
356 		goto exit;
357 	}
358 	dbg("%s - minor %d, count = %zd", __func__, dev->minor, count);
359 	/* if count is 0 we're already done */
360 	if (count == 0) {
361 		retval = 0;
362 		goto exit;
363 	}
364 	/* We only accept full reports */
365 	if (count != dev->report_size) {
366 		retval = -EINVAL;
367 		goto exit;
368 	}
369 	switch (dev->product_id) {
370 	case USB_DEVICE_ID_CODEMERCS_IOW24:
371 	case USB_DEVICE_ID_CODEMERCS_IOWPV1:
372 	case USB_DEVICE_ID_CODEMERCS_IOWPV2:
373 	case USB_DEVICE_ID_CODEMERCS_IOW40:
374 		/* IOW24 and IOW40 use a synchronous call */
375 		buf = kmalloc(8, GFP_KERNEL);	/* 8 bytes are enough for both products */
376 		if (!buf) {
377 			retval = -ENOMEM;
378 			goto exit;
379 		}
380 		if (copy_from_user(buf, user_buffer, count)) {
381 			retval = -EFAULT;
382 			kfree(buf);
383 			goto exit;
384 		}
385 		retval = usb_set_report(dev->interface, 2, 0, buf, count);
386 		kfree(buf);
387 		goto exit;
388 		break;
389 	case USB_DEVICE_ID_CODEMERCS_IOW56:
390 		/* The IOW56 uses asynchronous IO and more urbs */
391 		if (atomic_read(&dev->write_busy) == MAX_WRITES_IN_FLIGHT) {
392 			/* Wait until we are below the limit for submitted urbs */
393 			if (file->f_flags & O_NONBLOCK) {
394 				retval = -EAGAIN;
395 				goto exit;
396 			} else {
397 				retval = wait_event_interruptible(dev->write_wait,
398 								  (!dev->present || (atomic_read (&dev-> write_busy) < MAX_WRITES_IN_FLIGHT)));
399 				if (retval) {
400 					/* we were interrupted by a signal */
401 					retval = -ERESTART;
402 					goto exit;
403 				}
404 				if (!dev->present) {
405 					/* The device was unplugged */
406 					retval = -ENODEV;
407 					goto exit;
408 				}
409 				if (!dev->opened) {
410 					/* We were closed while waiting for an URB */
411 					retval = -ENODEV;
412 					goto exit;
413 				}
414 			}
415 		}
416 		atomic_inc(&dev->write_busy);
417 		int_out_urb = usb_alloc_urb(0, GFP_KERNEL);
418 		if (!int_out_urb) {
419 			retval = -ENOMEM;
420 			dbg("%s Unable to allocate urb ", __func__);
421 			goto error_no_urb;
422 		}
423 		buf = usb_buffer_alloc(dev->udev, dev->report_size,
424 				       GFP_KERNEL, &int_out_urb->transfer_dma);
425 		if (!buf) {
426 			retval = -ENOMEM;
427 			dbg("%s Unable to allocate buffer ", __func__);
428 			goto error_no_buffer;
429 		}
430 		usb_fill_int_urb(int_out_urb, dev->udev,
431 				 usb_sndintpipe(dev->udev,
432 						dev->int_out_endpoint->bEndpointAddress),
433 				 buf, dev->report_size,
434 				 iowarrior_write_callback, dev,
435 				 dev->int_out_endpoint->bInterval);
436 		int_out_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
437 		if (copy_from_user(buf, user_buffer, count)) {
438 			retval = -EFAULT;
439 			goto error;
440 		}
441 		retval = usb_submit_urb(int_out_urb, GFP_KERNEL);
442 		if (retval) {
443 			dbg("%s submit error %d for urb nr.%d", __func__,
444 			    retval, atomic_read(&dev->write_busy));
445 			goto error;
446 		}
447 		/* submit was ok */
448 		retval = count;
449 		usb_free_urb(int_out_urb);
450 		goto exit;
451 		break;
452 	default:
453 		/* what do we have here ? An unsupported Product-ID ? */
454 		dev_err(&dev->interface->dev, "%s - not supported for product=0x%x",
455 			__FUNCTION__, dev->product_id);
456 		retval = -EFAULT;
457 		goto exit;
458 		break;
459 	}
460 error:
461 	usb_buffer_free(dev->udev, dev->report_size, buf,
462 			int_out_urb->transfer_dma);
463 error_no_buffer:
464 	usb_free_urb(int_out_urb);
465 error_no_urb:
466 	atomic_dec(&dev->write_busy);
467 	wake_up_interruptible(&dev->write_wait);
468 exit:
469 	mutex_unlock(&dev->mutex);
470 	return retval;
471 }
472 
473 /**
474  *	iowarrior_ioctl
475  */
476 static int iowarrior_ioctl(struct inode *inode, struct file *file,
477 			   unsigned int cmd, unsigned long arg)
478 {
479 	struct iowarrior *dev = NULL;
480 	__u8 *buffer;
481 	__u8 __user *user_buffer;
482 	int retval;
483 	int io_res;		/* checks for bytes read/written and copy_to/from_user results */
484 
485 	dev = (struct iowarrior *)file->private_data;
486 	if (dev == NULL) {
487 		return -ENODEV;
488 	}
489 
490 	buffer = kzalloc(dev->report_size, GFP_KERNEL);
491 	if (!buffer)
492 		return -ENOMEM;
493 
494 	/* lock this object */
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 	dbg("%s - minor %d, cmd 0x%.4x, arg %ld", __func__, dev->minor, cmd,
504 	    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.",
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 < 0)
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 			/* directly from the descriptor */
554 			info.vendor = le16_to_cpu(dev->udev->descriptor.idVendor);
555 			info.product = dev->product_id;
556 			info.revision = le16_to_cpu(dev->udev->descriptor.bcdDevice);
557 
558 			/* 0==UNKNOWN, 1==LOW(usb1.1) ,2=FULL(usb1.1), 3=HIGH(usb2.0) */
559 			info.speed = le16_to_cpu(dev->udev->speed);
560 			info.if_num = dev->interface->cur_altsetting->desc.bInterfaceNumber;
561 			info.report_size = dev->report_size;
562 
563 			/* serial number string has been read earlier 8 chars or empty string */
564 			memcpy(info.serial, dev->chip_serial,
565 			       sizeof(dev->chip_serial));
566 			if (cfg_descriptor == NULL) {
567 				info.power = -1;	/* no information available */
568 			} else {
569 				/* the MaxPower is stored in units of 2mA to make it fit into a byte-value */
570 				info.power = cfg_descriptor->bMaxPower * 2;
571 			}
572 			io_res = copy_to_user((struct iowarrior_info __user *)arg, &info,
573 					 sizeof(struct iowarrior_info));
574 			if (io_res < 0)
575 				retval = -EFAULT;
576 			break;
577 		}
578 	default:
579 		/* return that we did not understand this ioctl call */
580 		retval = -ENOTTY;
581 		break;
582 	}
583 error_out:
584 	/* unlock the device */
585 	mutex_unlock(&dev->mutex);
586 	kfree(buffer);
587 	return retval;
588 }
589 
590 /**
591  *	iowarrior_open
592  */
593 static int iowarrior_open(struct inode *inode, struct file *file)
594 {
595 	struct iowarrior *dev = NULL;
596 	struct usb_interface *interface;
597 	int subminor;
598 	int retval = 0;
599 
600 	dbg("%s", __func__);
601 
602 	subminor = iminor(inode);
603 
604 	interface = usb_find_interface(&iowarrior_driver, subminor);
605 	if (!interface) {
606 		err("%s - error, can't find device for minor %d", __FUNCTION__,
607 		    subminor);
608 		return -ENODEV;
609 	}
610 
611 	dev = usb_get_intfdata(interface);
612 	if (!dev)
613 		return -ENODEV;
614 
615 	mutex_lock(&dev->mutex);
616 
617 	/* Only one process can open each device, no sharing. */
618 	if (dev->opened) {
619 		retval = -EBUSY;
620 		goto out;
621 	}
622 
623 	/* setup interrupt handler for receiving values */
624 	if ((retval = usb_submit_urb(dev->int_in_urb, GFP_KERNEL)) < 0) {
625 		dev_err(&interface->dev, "Error %d while submitting URB\n", retval);
626 		retval = -EFAULT;
627 		goto out;
628 	}
629 	/* increment our usage count for the driver */
630 	++dev->opened;
631 	/* save our object in the file's private structure */
632 	file->private_data = dev;
633 	retval = 0;
634 
635 out:
636 	mutex_unlock(&dev->mutex);
637 	return retval;
638 }
639 
640 /**
641  *	iowarrior_release
642  */
643 static int iowarrior_release(struct inode *inode, struct file *file)
644 {
645 	struct iowarrior *dev;
646 	int retval = 0;
647 
648 	dev = (struct iowarrior *)file->private_data;
649 	if (dev == NULL) {
650 		return -ENODEV;
651 	}
652 
653 	dbg("%s - minor %d", __func__, dev->minor);
654 
655 	/* lock our device */
656 	mutex_lock(&dev->mutex);
657 
658 	if (dev->opened <= 0) {
659 		retval = -ENODEV;	/* close called more than once */
660 		mutex_unlock(&dev->mutex);
661 	} else {
662 		dev->opened = 0;	/* we're closeing now */
663 		retval = 0;
664 		if (dev->present) {
665 			/*
666 			   The device is still connected so we only shutdown
667 			   pending read-/write-ops.
668 			 */
669 			usb_kill_urb(dev->int_in_urb);
670 			wake_up_interruptible(&dev->read_wait);
671 			wake_up_interruptible(&dev->write_wait);
672 			mutex_unlock(&dev->mutex);
673 		} else {
674 			/* The device was unplugged, cleanup resources */
675 			mutex_unlock(&dev->mutex);
676 			iowarrior_delete(dev);
677 		}
678 	}
679 	return retval;
680 }
681 
682 static unsigned iowarrior_poll(struct file *file, poll_table * wait)
683 {
684 	struct iowarrior *dev = file->private_data;
685 	unsigned int mask = 0;
686 
687 	if (!dev->present)
688 		return POLLERR | POLLHUP;
689 
690 	poll_wait(file, &dev->read_wait, wait);
691 	poll_wait(file, &dev->write_wait, wait);
692 
693 	if (!dev->present)
694 		return POLLERR | POLLHUP;
695 
696 	if (read_index(dev) != -1)
697 		mask |= POLLIN | POLLRDNORM;
698 
699 	if (atomic_read(&dev->write_busy) < MAX_WRITES_IN_FLIGHT)
700 		mask |= POLLOUT | POLLWRNORM;
701 	return mask;
702 }
703 
704 /*
705  * File operations needed when we register this driver.
706  * This assumes that this driver NEEDS file operations,
707  * of course, which means that the driver is expected
708  * to have a node in the /dev directory. If the USB
709  * device were for a network interface then the driver
710  * would use "struct net_driver" instead, and a serial
711  * device would use "struct tty_driver".
712  */
713 static struct file_operations iowarrior_fops = {
714 	.owner = THIS_MODULE,
715 	.write = iowarrior_write,
716 	.read = iowarrior_read,
717 	.ioctl = iowarrior_ioctl,
718 	.open = iowarrior_open,
719 	.release = iowarrior_release,
720 	.poll = iowarrior_poll,
721 };
722 
723 /*
724  * usb class driver info in order to get a minor number from the usb core,
725  * and to have the device registered with devfs and the driver core
726  */
727 static struct usb_class_driver iowarrior_class = {
728 	.name = "iowarrior%d",
729 	.fops = &iowarrior_fops,
730 	.minor_base = IOWARRIOR_MINOR_BASE,
731 };
732 
733 /*---------------------------------*/
734 /*  probe and disconnect functions */
735 /*---------------------------------*/
736 /**
737  *	iowarrior_probe
738  *
739  *	Called by the usb core when a new device is connected that it thinks
740  *	this driver might be interested in.
741  */
742 static int iowarrior_probe(struct usb_interface *interface,
743 			   const struct usb_device_id *id)
744 {
745 	struct usb_device *udev = interface_to_usbdev(interface);
746 	struct iowarrior *dev = NULL;
747 	struct usb_host_interface *iface_desc;
748 	struct usb_endpoint_descriptor *endpoint;
749 	int i;
750 	int retval = -ENOMEM;
751 
752 	/* allocate memory for our device state and intialize it */
753 	dev = kzalloc(sizeof(struct iowarrior), GFP_KERNEL);
754 	if (dev == NULL) {
755 		dev_err(&interface->dev, "Out of memory");
756 		return retval;
757 	}
758 
759 	mutex_init(&dev->mutex);
760 
761 	atomic_set(&dev->intr_idx, 0);
762 	atomic_set(&dev->read_idx, 0);
763 	spin_lock_init(&dev->intr_idx_lock);
764 	atomic_set(&dev->overflow_flag, 0);
765 	init_waitqueue_head(&dev->read_wait);
766 	atomic_set(&dev->write_busy, 0);
767 	init_waitqueue_head(&dev->write_wait);
768 
769 	dev->udev = udev;
770 	dev->interface = interface;
771 
772 	iface_desc = interface->cur_altsetting;
773 	dev->product_id = le16_to_cpu(udev->descriptor.idProduct);
774 
775 	/* set up the endpoint information */
776 	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
777 		endpoint = &iface_desc->endpoint[i].desc;
778 
779 		if (usb_endpoint_is_int_in(endpoint))
780 			dev->int_in_endpoint = endpoint;
781 		if (usb_endpoint_is_int_out(endpoint))
782 			/* this one will match for the IOWarrior56 only */
783 			dev->int_out_endpoint = endpoint;
784 	}
785 	/* we have to check the report_size often, so remember it in the endianess suitable for our machine */
786 	dev->report_size = le16_to_cpu(dev->int_in_endpoint->wMaxPacketSize);
787 	if ((dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) &&
788 	    (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW56))
789 		/* IOWarrior56 has wMaxPacketSize different from report size */
790 		dev->report_size = 7;
791 
792 	/* create the urb and buffer for reading */
793 	dev->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);
794 	if (!dev->int_in_urb) {
795 		dev_err(&interface->dev, "Couldn't allocate interrupt_in_urb\n");
796 		goto error;
797 	}
798 	dev->int_in_buffer = kmalloc(dev->report_size, GFP_KERNEL);
799 	if (!dev->int_in_buffer) {
800 		dev_err(&interface->dev, "Couldn't allocate int_in_buffer\n");
801 		goto error;
802 	}
803 	usb_fill_int_urb(dev->int_in_urb, dev->udev,
804 			 usb_rcvintpipe(dev->udev,
805 					dev->int_in_endpoint->bEndpointAddress),
806 			 dev->int_in_buffer, dev->report_size,
807 			 iowarrior_callback, dev,
808 			 dev->int_in_endpoint->bInterval);
809 	/* create an internal buffer for interrupt data from the device */
810 	dev->read_queue =
811 	    kmalloc(((dev->report_size + 1) * MAX_INTERRUPT_BUFFER),
812 		    GFP_KERNEL);
813 	if (!dev->read_queue) {
814 		dev_err(&interface->dev, "Couldn't allocate read_queue\n");
815 		goto error;
816 	}
817 	/* Get the serial-number of the chip */
818 	memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
819 	usb_string(udev, udev->descriptor.iSerialNumber, dev->chip_serial,
820 		   sizeof(dev->chip_serial));
821 	if (strlen(dev->chip_serial) != 8)
822 		memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
823 
824 	/* Set the idle timeout to 0, if this is interface 0 */
825 	if (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) {
826 	    usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
827 			    0x0A,
828 			    USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0,
829 			    0, NULL, 0, USB_CTRL_SET_TIMEOUT);
830 	}
831 	/* allow device read and ioctl */
832 	dev->present = 1;
833 
834 	/* we can register the device now, as it is ready */
835 	usb_set_intfdata(interface, dev);
836 
837 	retval = usb_register_dev(interface, &iowarrior_class);
838 	if (retval) {
839 		/* something prevented us from registering this driver */
840 		dev_err(&interface->dev, "Not able to get a minor for this device.\n");
841 		usb_set_intfdata(interface, NULL);
842 		goto error;
843 	}
844 
845 	dev->minor = interface->minor;
846 
847 	/* let the user know what node this device is now attached to */
848 	dev_info(&interface->dev, "IOWarrior product=0x%x, serial=%s interface=%d "
849 		 "now attached to iowarrior%d\n", dev->product_id, dev->chip_serial,
850 		 iface_desc->desc.bInterfaceNumber, dev->minor - IOWARRIOR_MINOR_BASE);
851 	return retval;
852 
853 error:
854 	iowarrior_delete(dev);
855 	return retval;
856 }
857 
858 /**
859  *	iowarrior_disconnect
860  *
861  *	Called by the usb core when the device is removed from the system.
862  */
863 static void iowarrior_disconnect(struct usb_interface *interface)
864 {
865 	struct iowarrior *dev;
866 	int minor;
867 
868 	dev = usb_get_intfdata(interface);
869 	usb_set_intfdata(interface, NULL);
870 
871 	minor = dev->minor;
872 
873 	/* give back our minor */
874 	usb_deregister_dev(interface, &iowarrior_class);
875 
876 	mutex_lock(&dev->mutex);
877 
878 	/* prevent device read, write and ioctl */
879 	dev->present = 0;
880 
881 	mutex_unlock(&dev->mutex);
882 
883 	if (dev->opened) {
884 		/* There is a process that holds a filedescriptor to the device ,
885 		   so we only shutdown read-/write-ops going on.
886 		   Deleting the device is postponed until close() was called.
887 		 */
888 		usb_kill_urb(dev->int_in_urb);
889 		wake_up_interruptible(&dev->read_wait);
890 		wake_up_interruptible(&dev->write_wait);
891 	} else {
892 		/* no process is using the device, cleanup now */
893 		iowarrior_delete(dev);
894 	}
895 
896 	dev_info(&interface->dev, "I/O-Warror #%d now disconnected\n",
897 		 minor - IOWARRIOR_MINOR_BASE);
898 }
899 
900 /* usb specific object needed to register this driver with the usb subsystem */
901 static struct usb_driver iowarrior_driver = {
902 	.name = "iowarrior",
903 	.probe = iowarrior_probe,
904 	.disconnect = iowarrior_disconnect,
905 	.id_table = iowarrior_ids,
906 };
907 
908 static int __init iowarrior_init(void)
909 {
910 	return usb_register(&iowarrior_driver);
911 }
912 
913 static void __exit iowarrior_exit(void)
914 {
915 	usb_deregister(&iowarrior_driver);
916 }
917 
918 module_init(iowarrior_init);
919 module_exit(iowarrior_exit);
920