xref: /openbmc/linux/drivers/usb/misc/iowarrior.c (revision 1eb4c977)
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/mutex.h>
22 #include <linux/poll.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 official 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 DEFINE_MUTEX(iowarrior_mutex);
65 static bool debug = 0;
66 module_param(debug, bool, 0644);
67 MODULE_PARM_DESC(debug, "debug=1 enables debugging messages");
68 
69 static struct usb_driver iowarrior_driver;
70 static DEFINE_MUTEX(iowarrior_open_disc_lock);
71 
72 /*--------------*/
73 /*     data     */
74 /*--------------*/
75 
76 /* Structure to hold all of our device specific stuff */
77 struct iowarrior {
78 	struct mutex mutex;			/* locks this structure */
79 	struct usb_device *udev;		/* save off the usb device pointer */
80 	struct usb_interface *interface;	/* the interface for this device */
81 	unsigned char minor;			/* the starting minor number for this device */
82 	struct usb_endpoint_descriptor *int_out_endpoint;	/* endpoint for reading (needed for IOW56 only) */
83 	struct usb_endpoint_descriptor *int_in_endpoint;	/* endpoint for reading */
84 	struct urb *int_in_urb;		/* the urb for reading data */
85 	unsigned char *int_in_buffer;	/* buffer for data to be read */
86 	unsigned char serial_number;	/* to detect lost packages */
87 	unsigned char *read_queue;	/* size is MAX_INTERRUPT_BUFFER * packet size */
88 	wait_queue_head_t read_wait;
89 	wait_queue_head_t write_wait;	/* wait-queue for writing to the device */
90 	atomic_t write_busy;		/* number of write-urbs submitted */
91 	atomic_t read_idx;
92 	atomic_t intr_idx;
93 	spinlock_t intr_idx_lock;	/* protects intr_idx */
94 	atomic_t overflow_flag;		/* signals an index 'rollover' */
95 	int present;			/* this is 1 as long as the device is connected */
96 	int opened;			/* this is 1 if the device is currently open */
97 	char chip_serial[9];		/* the serial number string of the chip connected */
98 	int report_size;		/* number of bytes in a report */
99 	u16 product_id;
100 };
101 
102 /*--------------*/
103 /*    globals   */
104 /*--------------*/
105 
106 /*
107  *  USB spec identifies 5 second timeouts.
108  */
109 #define GET_TIMEOUT 5
110 #define USB_REQ_GET_REPORT  0x01
111 //#if 0
112 static int usb_get_report(struct usb_device *dev,
113 			  struct usb_host_interface *inter, unsigned char type,
114 			  unsigned char id, void *buf, int size)
115 {
116 	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
117 			       USB_REQ_GET_REPORT,
118 			       USB_DIR_IN | USB_TYPE_CLASS |
119 			       USB_RECIP_INTERFACE, (type << 8) + id,
120 			       inter->desc.bInterfaceNumber, buf, size,
121 			       GET_TIMEOUT*HZ);
122 }
123 //#endif
124 
125 #define USB_REQ_SET_REPORT 0x09
126 
127 static int usb_set_report(struct usb_interface *intf, unsigned char type,
128 			  unsigned char id, void *buf, int size)
129 {
130 	return usb_control_msg(interface_to_usbdev(intf),
131 			       usb_sndctrlpipe(interface_to_usbdev(intf), 0),
132 			       USB_REQ_SET_REPORT,
133 			       USB_TYPE_CLASS | USB_RECIP_INTERFACE,
134 			       (type << 8) + id,
135 			       intf->cur_altsetting->desc.bInterfaceNumber, buf,
136 			       size, HZ);
137 }
138 
139 /*---------------------*/
140 /* driver registration */
141 /*---------------------*/
142 /* table of devices that work with this driver */
143 static const struct usb_device_id iowarrior_ids[] = {
144 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW40)},
145 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW24)},
146 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV1)},
147 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV2)},
148 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW56)},
149 	{}			/* Terminating entry */
150 };
151 MODULE_DEVICE_TABLE(usb, iowarrior_ids);
152 
153 /*
154  * USB callback handler for reading data
155  */
156 static void iowarrior_callback(struct urb *urb)
157 {
158 	struct iowarrior *dev = urb->context;
159 	int intr_idx;
160 	int read_idx;
161 	int aux_idx;
162 	int offset;
163 	int status = urb->status;
164 	int retval;
165 
166 	switch (status) {
167 	case 0:
168 		/* success */
169 		break;
170 	case -ECONNRESET:
171 	case -ENOENT:
172 	case -ESHUTDOWN:
173 		return;
174 	default:
175 		goto exit;
176 	}
177 
178 	spin_lock(&dev->intr_idx_lock);
179 	intr_idx = atomic_read(&dev->intr_idx);
180 	/* aux_idx become previous intr_idx */
181 	aux_idx = (intr_idx == 0) ? (MAX_INTERRUPT_BUFFER - 1) : (intr_idx - 1);
182 	read_idx = atomic_read(&dev->read_idx);
183 
184 	/* queue is not empty and it's interface 0 */
185 	if ((intr_idx != read_idx)
186 	    && (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0)) {
187 		/* + 1 for serial number */
188 		offset = aux_idx * (dev->report_size + 1);
189 		if (!memcmp
190 		    (dev->read_queue + offset, urb->transfer_buffer,
191 		     dev->report_size)) {
192 			/* equal values on interface 0 will be ignored */
193 			spin_unlock(&dev->intr_idx_lock);
194 			goto exit;
195 		}
196 	}
197 
198 	/* aux_idx become next intr_idx */
199 	aux_idx = (intr_idx == (MAX_INTERRUPT_BUFFER - 1)) ? 0 : (intr_idx + 1);
200 	if (read_idx == aux_idx) {
201 		/* queue full, dropping oldest input */
202 		read_idx = (++read_idx == MAX_INTERRUPT_BUFFER) ? 0 : read_idx;
203 		atomic_set(&dev->read_idx, read_idx);
204 		atomic_set(&dev->overflow_flag, 1);
205 	}
206 
207 	/* +1 for serial number */
208 	offset = intr_idx * (dev->report_size + 1);
209 	memcpy(dev->read_queue + offset, urb->transfer_buffer,
210 	       dev->report_size);
211 	*(dev->read_queue + offset + (dev->report_size)) = dev->serial_number++;
212 
213 	atomic_set(&dev->intr_idx, aux_idx);
214 	spin_unlock(&dev->intr_idx_lock);
215 	/* tell the blocking read about the new data */
216 	wake_up_interruptible(&dev->read_wait);
217 
218 exit:
219 	retval = usb_submit_urb(urb, GFP_ATOMIC);
220 	if (retval)
221 		dev_err(&dev->interface->dev, "%s - usb_submit_urb failed with result %d\n",
222 			__func__, retval);
223 
224 }
225 
226 /*
227  * USB Callback handler for write-ops
228  */
229 static void iowarrior_write_callback(struct urb *urb)
230 {
231 	struct iowarrior *dev;
232 	int status = urb->status;
233 
234 	dev = urb->context;
235 	/* sync/async unlink faults aren't errors */
236 	if (status &&
237 	    !(status == -ENOENT ||
238 	      status == -ECONNRESET || status == -ESHUTDOWN)) {
239 		dbg("%s - nonzero write bulk status received: %d",
240 		    __func__, status);
241 	}
242 	/* free up our allocated buffer */
243 	usb_free_coherent(urb->dev, urb->transfer_buffer_length,
244 			  urb->transfer_buffer, urb->transfer_dma);
245 	/* tell a waiting writer the interrupt-out-pipe is available again */
246 	atomic_dec(&dev->write_busy);
247 	wake_up_interruptible(&dev->write_wait);
248 }
249 
250 /**
251  *	iowarrior_delete
252  */
253 static inline void iowarrior_delete(struct iowarrior *dev)
254 {
255 	dbg("%s - minor %d", __func__, dev->minor);
256 	kfree(dev->int_in_buffer);
257 	usb_free_urb(dev->int_in_urb);
258 	kfree(dev->read_queue);
259 	kfree(dev);
260 }
261 
262 /*---------------------*/
263 /* fops implementation */
264 /*---------------------*/
265 
266 static int read_index(struct iowarrior *dev)
267 {
268 	int intr_idx, read_idx;
269 
270 	read_idx = atomic_read(&dev->read_idx);
271 	intr_idx = atomic_read(&dev->intr_idx);
272 
273 	return (read_idx == intr_idx ? -1 : read_idx);
274 }
275 
276 /**
277  *  iowarrior_read
278  */
279 static ssize_t iowarrior_read(struct file *file, char __user *buffer,
280 			      size_t count, loff_t *ppos)
281 {
282 	struct iowarrior *dev;
283 	int read_idx;
284 	int offset;
285 
286 	dev = file->private_data;
287 
288 	/* verify that the device wasn't unplugged */
289 	if (dev == NULL || !dev->present)
290 		return -ENODEV;
291 
292 	dbg("%s - minor %d, count = %zd", __func__, dev->minor, count);
293 
294 	/* read count must be packet size (+ time stamp) */
295 	if ((count != dev->report_size)
296 	    && (count != (dev->report_size + 1)))
297 		return -EINVAL;
298 
299 	/* repeat until no buffer overrun in callback handler occur */
300 	do {
301 		atomic_set(&dev->overflow_flag, 0);
302 		if ((read_idx = read_index(dev)) == -1) {
303 			/* queue emty */
304 			if (file->f_flags & O_NONBLOCK)
305 				return -EAGAIN;
306 			else {
307 				//next line will return when there is either new data, or the device is unplugged
308 				int r = wait_event_interruptible(dev->read_wait,
309 								 (!dev->present
310 								  || (read_idx =
311 								      read_index
312 								      (dev)) !=
313 								  -1));
314 				if (r) {
315 					//we were interrupted by a signal
316 					return -ERESTART;
317 				}
318 				if (!dev->present) {
319 					//The device was unplugged
320 					return -ENODEV;
321 				}
322 				if (read_idx == -1) {
323 					// Can this happen ???
324 					return 0;
325 				}
326 			}
327 		}
328 
329 		offset = read_idx * (dev->report_size + 1);
330 		if (copy_to_user(buffer, dev->read_queue + offset, count)) {
331 			return -EFAULT;
332 		}
333 	} while (atomic_read(&dev->overflow_flag));
334 
335 	read_idx = ++read_idx == MAX_INTERRUPT_BUFFER ? 0 : read_idx;
336 	atomic_set(&dev->read_idx, read_idx);
337 	return count;
338 }
339 
340 /*
341  * iowarrior_write
342  */
343 static ssize_t iowarrior_write(struct file *file,
344 			       const char __user *user_buffer,
345 			       size_t count, loff_t *ppos)
346 {
347 	struct iowarrior *dev;
348 	int retval = 0;
349 	char *buf = NULL;	/* for IOW24 and IOW56 we need a buffer */
350 	struct urb *int_out_urb = NULL;
351 
352 	dev = file->private_data;
353 
354 	mutex_lock(&dev->mutex);
355 	/* verify that the device wasn't unplugged */
356 	if (!dev->present) {
357 		retval = -ENODEV;
358 		goto exit;
359 	}
360 	dbg("%s - minor %d, count = %zd", __func__, dev->minor, count);
361 	/* if count is 0 we're already done */
362 	if (count == 0) {
363 		retval = 0;
364 		goto exit;
365 	}
366 	/* We only accept full reports */
367 	if (count != dev->report_size) {
368 		retval = -EINVAL;
369 		goto exit;
370 	}
371 	switch (dev->product_id) {
372 	case USB_DEVICE_ID_CODEMERCS_IOW24:
373 	case USB_DEVICE_ID_CODEMERCS_IOWPV1:
374 	case USB_DEVICE_ID_CODEMERCS_IOWPV2:
375 	case USB_DEVICE_ID_CODEMERCS_IOW40:
376 		/* IOW24 and IOW40 use a synchronous call */
377 		buf = kmalloc(count, GFP_KERNEL);
378 		if (!buf) {
379 			retval = -ENOMEM;
380 			goto exit;
381 		}
382 		if (copy_from_user(buf, user_buffer, count)) {
383 			retval = -EFAULT;
384 			kfree(buf);
385 			goto exit;
386 		}
387 		retval = usb_set_report(dev->interface, 2, 0, buf, count);
388 		kfree(buf);
389 		goto exit;
390 		break;
391 	case USB_DEVICE_ID_CODEMERCS_IOW56:
392 		/* The IOW56 uses asynchronous IO and more urbs */
393 		if (atomic_read(&dev->write_busy) == MAX_WRITES_IN_FLIGHT) {
394 			/* Wait until we are below the limit for submitted urbs */
395 			if (file->f_flags & O_NONBLOCK) {
396 				retval = -EAGAIN;
397 				goto exit;
398 			} else {
399 				retval = wait_event_interruptible(dev->write_wait,
400 								  (!dev->present || (atomic_read (&dev-> write_busy) < MAX_WRITES_IN_FLIGHT)));
401 				if (retval) {
402 					/* we were interrupted by a signal */
403 					retval = -ERESTART;
404 					goto exit;
405 				}
406 				if (!dev->present) {
407 					/* The device was unplugged */
408 					retval = -ENODEV;
409 					goto exit;
410 				}
411 				if (!dev->opened) {
412 					/* We were closed while waiting for an URB */
413 					retval = -ENODEV;
414 					goto exit;
415 				}
416 			}
417 		}
418 		atomic_inc(&dev->write_busy);
419 		int_out_urb = usb_alloc_urb(0, GFP_KERNEL);
420 		if (!int_out_urb) {
421 			retval = -ENOMEM;
422 			dbg("%s Unable to allocate urb ", __func__);
423 			goto error_no_urb;
424 		}
425 		buf = usb_alloc_coherent(dev->udev, dev->report_size,
426 					 GFP_KERNEL, &int_out_urb->transfer_dma);
427 		if (!buf) {
428 			retval = -ENOMEM;
429 			dbg("%s Unable to allocate buffer ", __func__);
430 			goto error_no_buffer;
431 		}
432 		usb_fill_int_urb(int_out_urb, dev->udev,
433 				 usb_sndintpipe(dev->udev,
434 						dev->int_out_endpoint->bEndpointAddress),
435 				 buf, dev->report_size,
436 				 iowarrior_write_callback, dev,
437 				 dev->int_out_endpoint->bInterval);
438 		int_out_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
439 		if (copy_from_user(buf, user_buffer, count)) {
440 			retval = -EFAULT;
441 			goto error;
442 		}
443 		retval = usb_submit_urb(int_out_urb, GFP_KERNEL);
444 		if (retval) {
445 			dbg("%s submit error %d for urb nr.%d", __func__,
446 			    retval, atomic_read(&dev->write_busy));
447 			goto error;
448 		}
449 		/* submit was ok */
450 		retval = count;
451 		usb_free_urb(int_out_urb);
452 		goto exit;
453 		break;
454 	default:
455 		/* what do we have here ? An unsupported Product-ID ? */
456 		dev_err(&dev->interface->dev, "%s - not supported for product=0x%x\n",
457 			__func__, dev->product_id);
458 		retval = -EFAULT;
459 		goto exit;
460 		break;
461 	}
462 error:
463 	usb_free_coherent(dev->udev, dev->report_size, buf,
464 			  int_out_urb->transfer_dma);
465 error_no_buffer:
466 	usb_free_urb(int_out_urb);
467 error_no_urb:
468 	atomic_dec(&dev->write_busy);
469 	wake_up_interruptible(&dev->write_wait);
470 exit:
471 	mutex_unlock(&dev->mutex);
472 	return retval;
473 }
474 
475 /**
476  *	iowarrior_ioctl
477  */
478 static long iowarrior_ioctl(struct file *file, unsigned int cmd,
479 							unsigned long arg)
480 {
481 	struct iowarrior *dev = NULL;
482 	__u8 *buffer;
483 	__u8 __user *user_buffer;
484 	int retval;
485 	int io_res;		/* checks for bytes read/written and copy_to/from_user results */
486 
487 	dev = file->private_data;
488 	if (dev == NULL) {
489 		return -ENODEV;
490 	}
491 
492 	buffer = kzalloc(dev->report_size, GFP_KERNEL);
493 	if (!buffer)
494 		return -ENOMEM;
495 
496 	/* lock this object */
497 	mutex_lock(&iowarrior_mutex);
498 	mutex_lock(&dev->mutex);
499 
500 	/* verify that the device wasn't unplugged */
501 	if (!dev->present) {
502 		retval = -ENODEV;
503 		goto error_out;
504 	}
505 
506 	dbg("%s - minor %d, cmd 0x%.4x, arg %ld", __func__, dev->minor, cmd,
507 	    arg);
508 
509 	retval = 0;
510 	io_res = 0;
511 	switch (cmd) {
512 	case IOW_WRITE:
513 		if (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW24 ||
514 		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV1 ||
515 		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV2 ||
516 		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW40) {
517 			user_buffer = (__u8 __user *)arg;
518 			io_res = copy_from_user(buffer, user_buffer,
519 						dev->report_size);
520 			if (io_res) {
521 				retval = -EFAULT;
522 			} else {
523 				io_res = usb_set_report(dev->interface, 2, 0,
524 							buffer,
525 							dev->report_size);
526 				if (io_res < 0)
527 					retval = io_res;
528 			}
529 		} else {
530 			retval = -EINVAL;
531 			dev_err(&dev->interface->dev,
532 				"ioctl 'IOW_WRITE' is not supported for product=0x%x.\n",
533 				dev->product_id);
534 		}
535 		break;
536 	case IOW_READ:
537 		user_buffer = (__u8 __user *)arg;
538 		io_res = usb_get_report(dev->udev,
539 					dev->interface->cur_altsetting, 1, 0,
540 					buffer, dev->report_size);
541 		if (io_res < 0)
542 			retval = io_res;
543 		else {
544 			io_res = copy_to_user(user_buffer, buffer, dev->report_size);
545 			if (io_res)
546 				retval = -EFAULT;
547 		}
548 		break;
549 	case IOW_GETINFO:
550 		{
551 			/* Report available information for the device */
552 			struct iowarrior_info info;
553 			/* needed for power consumption */
554 			struct usb_config_descriptor *cfg_descriptor = &dev->udev->actconfig->desc;
555 
556 			memset(&info, 0, sizeof(info));
557 			/* directly from the descriptor */
558 			info.vendor = le16_to_cpu(dev->udev->descriptor.idVendor);
559 			info.product = dev->product_id;
560 			info.revision = le16_to_cpu(dev->udev->descriptor.bcdDevice);
561 
562 			/* 0==UNKNOWN, 1==LOW(usb1.1) ,2=FULL(usb1.1), 3=HIGH(usb2.0) */
563 			info.speed = le16_to_cpu(dev->udev->speed);
564 			info.if_num = dev->interface->cur_altsetting->desc.bInterfaceNumber;
565 			info.report_size = dev->report_size;
566 
567 			/* serial number string has been read earlier 8 chars or empty string */
568 			memcpy(info.serial, dev->chip_serial,
569 			       sizeof(dev->chip_serial));
570 			if (cfg_descriptor == NULL) {
571 				info.power = -1;	/* no information available */
572 			} else {
573 				/* the MaxPower is stored in units of 2mA to make it fit into a byte-value */
574 				info.power = cfg_descriptor->bMaxPower * 2;
575 			}
576 			io_res = copy_to_user((struct iowarrior_info __user *)arg, &info,
577 					 sizeof(struct iowarrior_info));
578 			if (io_res)
579 				retval = -EFAULT;
580 			break;
581 		}
582 	default:
583 		/* return that we did not understand this ioctl call */
584 		retval = -ENOTTY;
585 		break;
586 	}
587 error_out:
588 	/* unlock the device */
589 	mutex_unlock(&dev->mutex);
590 	mutex_unlock(&iowarrior_mutex);
591 	kfree(buffer);
592 	return retval;
593 }
594 
595 /**
596  *	iowarrior_open
597  */
598 static int iowarrior_open(struct inode *inode, struct file *file)
599 {
600 	struct iowarrior *dev = NULL;
601 	struct usb_interface *interface;
602 	int subminor;
603 	int retval = 0;
604 
605 	dbg("%s", __func__);
606 
607 	mutex_lock(&iowarrior_mutex);
608 	subminor = iminor(inode);
609 
610 	interface = usb_find_interface(&iowarrior_driver, subminor);
611 	if (!interface) {
612 		mutex_unlock(&iowarrior_mutex);
613 		err("%s - error, can't find device for minor %d", __func__,
614 		    subminor);
615 		return -ENODEV;
616 	}
617 
618 	mutex_lock(&iowarrior_open_disc_lock);
619 	dev = usb_get_intfdata(interface);
620 	if (!dev) {
621 		mutex_unlock(&iowarrior_open_disc_lock);
622 		mutex_unlock(&iowarrior_mutex);
623 		return -ENODEV;
624 	}
625 
626 	mutex_lock(&dev->mutex);
627 	mutex_unlock(&iowarrior_open_disc_lock);
628 
629 	/* Only one process can open each device, no sharing. */
630 	if (dev->opened) {
631 		retval = -EBUSY;
632 		goto out;
633 	}
634 
635 	/* setup interrupt handler for receiving values */
636 	if ((retval = usb_submit_urb(dev->int_in_urb, GFP_KERNEL)) < 0) {
637 		dev_err(&interface->dev, "Error %d while submitting URB\n", retval);
638 		retval = -EFAULT;
639 		goto out;
640 	}
641 	/* increment our usage count for the driver */
642 	++dev->opened;
643 	/* save our object in the file's private structure */
644 	file->private_data = dev;
645 	retval = 0;
646 
647 out:
648 	mutex_unlock(&dev->mutex);
649 	mutex_unlock(&iowarrior_mutex);
650 	return retval;
651 }
652 
653 /**
654  *	iowarrior_release
655  */
656 static int iowarrior_release(struct inode *inode, struct file *file)
657 {
658 	struct iowarrior *dev;
659 	int retval = 0;
660 
661 	dev = file->private_data;
662 	if (dev == NULL) {
663 		return -ENODEV;
664 	}
665 
666 	dbg("%s - minor %d", __func__, dev->minor);
667 
668 	/* lock our device */
669 	mutex_lock(&dev->mutex);
670 
671 	if (dev->opened <= 0) {
672 		retval = -ENODEV;	/* close called more than once */
673 		mutex_unlock(&dev->mutex);
674 	} else {
675 		dev->opened = 0;	/* we're closeing now */
676 		retval = 0;
677 		if (dev->present) {
678 			/*
679 			   The device is still connected so we only shutdown
680 			   pending read-/write-ops.
681 			 */
682 			usb_kill_urb(dev->int_in_urb);
683 			wake_up_interruptible(&dev->read_wait);
684 			wake_up_interruptible(&dev->write_wait);
685 			mutex_unlock(&dev->mutex);
686 		} else {
687 			/* The device was unplugged, cleanup resources */
688 			mutex_unlock(&dev->mutex);
689 			iowarrior_delete(dev);
690 		}
691 	}
692 	return retval;
693 }
694 
695 static unsigned iowarrior_poll(struct file *file, poll_table * wait)
696 {
697 	struct iowarrior *dev = file->private_data;
698 	unsigned int mask = 0;
699 
700 	if (!dev->present)
701 		return POLLERR | POLLHUP;
702 
703 	poll_wait(file, &dev->read_wait, wait);
704 	poll_wait(file, &dev->write_wait, wait);
705 
706 	if (!dev->present)
707 		return POLLERR | POLLHUP;
708 
709 	if (read_index(dev) != -1)
710 		mask |= POLLIN | POLLRDNORM;
711 
712 	if (atomic_read(&dev->write_busy) < MAX_WRITES_IN_FLIGHT)
713 		mask |= POLLOUT | POLLWRNORM;
714 	return mask;
715 }
716 
717 /*
718  * File operations needed when we register this driver.
719  * This assumes that this driver NEEDS file operations,
720  * of course, which means that the driver is expected
721  * to have a node in the /dev directory. If the USB
722  * device were for a network interface then the driver
723  * would use "struct net_driver" instead, and a serial
724  * device would use "struct tty_driver".
725  */
726 static const struct file_operations iowarrior_fops = {
727 	.owner = THIS_MODULE,
728 	.write = iowarrior_write,
729 	.read = iowarrior_read,
730 	.unlocked_ioctl = iowarrior_ioctl,
731 	.open = iowarrior_open,
732 	.release = iowarrior_release,
733 	.poll = iowarrior_poll,
734 	.llseek = noop_llseek,
735 };
736 
737 static char *iowarrior_devnode(struct device *dev, umode_t *mode)
738 {
739 	return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
740 }
741 
742 /*
743  * usb class driver info in order to get a minor number from the usb core,
744  * and to have the device registered with devfs and the driver core
745  */
746 static struct usb_class_driver iowarrior_class = {
747 	.name = "iowarrior%d",
748 	.devnode = iowarrior_devnode,
749 	.fops = &iowarrior_fops,
750 	.minor_base = IOWARRIOR_MINOR_BASE,
751 };
752 
753 /*---------------------------------*/
754 /*  probe and disconnect functions */
755 /*---------------------------------*/
756 /**
757  *	iowarrior_probe
758  *
759  *	Called by the usb core when a new device is connected that it thinks
760  *	this driver might be interested in.
761  */
762 static int iowarrior_probe(struct usb_interface *interface,
763 			   const struct usb_device_id *id)
764 {
765 	struct usb_device *udev = interface_to_usbdev(interface);
766 	struct iowarrior *dev = NULL;
767 	struct usb_host_interface *iface_desc;
768 	struct usb_endpoint_descriptor *endpoint;
769 	int i;
770 	int retval = -ENOMEM;
771 
772 	/* allocate memory for our device state and initialize it */
773 	dev = kzalloc(sizeof(struct iowarrior), GFP_KERNEL);
774 	if (dev == NULL) {
775 		dev_err(&interface->dev, "Out of memory\n");
776 		return retval;
777 	}
778 
779 	mutex_init(&dev->mutex);
780 
781 	atomic_set(&dev->intr_idx, 0);
782 	atomic_set(&dev->read_idx, 0);
783 	spin_lock_init(&dev->intr_idx_lock);
784 	atomic_set(&dev->overflow_flag, 0);
785 	init_waitqueue_head(&dev->read_wait);
786 	atomic_set(&dev->write_busy, 0);
787 	init_waitqueue_head(&dev->write_wait);
788 
789 	dev->udev = udev;
790 	dev->interface = interface;
791 
792 	iface_desc = interface->cur_altsetting;
793 	dev->product_id = le16_to_cpu(udev->descriptor.idProduct);
794 
795 	/* set up the endpoint information */
796 	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
797 		endpoint = &iface_desc->endpoint[i].desc;
798 
799 		if (usb_endpoint_is_int_in(endpoint))
800 			dev->int_in_endpoint = endpoint;
801 		if (usb_endpoint_is_int_out(endpoint))
802 			/* this one will match for the IOWarrior56 only */
803 			dev->int_out_endpoint = endpoint;
804 	}
805 	/* we have to check the report_size often, so remember it in the endianess suitable for our machine */
806 	dev->report_size = usb_endpoint_maxp(dev->int_in_endpoint);
807 	if ((dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) &&
808 	    (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW56))
809 		/* IOWarrior56 has wMaxPacketSize different from report size */
810 		dev->report_size = 7;
811 
812 	/* create the urb and buffer for reading */
813 	dev->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);
814 	if (!dev->int_in_urb) {
815 		dev_err(&interface->dev, "Couldn't allocate interrupt_in_urb\n");
816 		goto error;
817 	}
818 	dev->int_in_buffer = kmalloc(dev->report_size, GFP_KERNEL);
819 	if (!dev->int_in_buffer) {
820 		dev_err(&interface->dev, "Couldn't allocate int_in_buffer\n");
821 		goto error;
822 	}
823 	usb_fill_int_urb(dev->int_in_urb, dev->udev,
824 			 usb_rcvintpipe(dev->udev,
825 					dev->int_in_endpoint->bEndpointAddress),
826 			 dev->int_in_buffer, dev->report_size,
827 			 iowarrior_callback, dev,
828 			 dev->int_in_endpoint->bInterval);
829 	/* create an internal buffer for interrupt data from the device */
830 	dev->read_queue =
831 	    kmalloc(((dev->report_size + 1) * MAX_INTERRUPT_BUFFER),
832 		    GFP_KERNEL);
833 	if (!dev->read_queue) {
834 		dev_err(&interface->dev, "Couldn't allocate read_queue\n");
835 		goto error;
836 	}
837 	/* Get the serial-number of the chip */
838 	memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
839 	usb_string(udev, udev->descriptor.iSerialNumber, dev->chip_serial,
840 		   sizeof(dev->chip_serial));
841 	if (strlen(dev->chip_serial) != 8)
842 		memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
843 
844 	/* Set the idle timeout to 0, if this is interface 0 */
845 	if (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) {
846 	    usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
847 			    0x0A,
848 			    USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0,
849 			    0, NULL, 0, USB_CTRL_SET_TIMEOUT);
850 	}
851 	/* allow device read and ioctl */
852 	dev->present = 1;
853 
854 	/* we can register the device now, as it is ready */
855 	usb_set_intfdata(interface, dev);
856 
857 	retval = usb_register_dev(interface, &iowarrior_class);
858 	if (retval) {
859 		/* something prevented us from registering this driver */
860 		dev_err(&interface->dev, "Not able to get a minor for this device.\n");
861 		usb_set_intfdata(interface, NULL);
862 		goto error;
863 	}
864 
865 	dev->minor = interface->minor;
866 
867 	/* let the user know what node this device is now attached to */
868 	dev_info(&interface->dev, "IOWarrior product=0x%x, serial=%s interface=%d "
869 		 "now attached to iowarrior%d\n", dev->product_id, dev->chip_serial,
870 		 iface_desc->desc.bInterfaceNumber, dev->minor - IOWARRIOR_MINOR_BASE);
871 	return retval;
872 
873 error:
874 	iowarrior_delete(dev);
875 	return retval;
876 }
877 
878 /**
879  *	iowarrior_disconnect
880  *
881  *	Called by the usb core when the device is removed from the system.
882  */
883 static void iowarrior_disconnect(struct usb_interface *interface)
884 {
885 	struct iowarrior *dev;
886 	int minor;
887 
888 	dev = usb_get_intfdata(interface);
889 	mutex_lock(&iowarrior_open_disc_lock);
890 	usb_set_intfdata(interface, NULL);
891 
892 	minor = dev->minor;
893 
894 	/* give back our minor */
895 	usb_deregister_dev(interface, &iowarrior_class);
896 
897 	mutex_lock(&dev->mutex);
898 
899 	/* prevent device read, write and ioctl */
900 	dev->present = 0;
901 
902 	mutex_unlock(&dev->mutex);
903 	mutex_unlock(&iowarrior_open_disc_lock);
904 
905 	if (dev->opened) {
906 		/* There is a process that holds a filedescriptor to the device ,
907 		   so we only shutdown read-/write-ops going on.
908 		   Deleting the device is postponed until close() was called.
909 		 */
910 		usb_kill_urb(dev->int_in_urb);
911 		wake_up_interruptible(&dev->read_wait);
912 		wake_up_interruptible(&dev->write_wait);
913 	} else {
914 		/* no process is using the device, cleanup now */
915 		iowarrior_delete(dev);
916 	}
917 
918 	dev_info(&interface->dev, "I/O-Warror #%d now disconnected\n",
919 		 minor - IOWARRIOR_MINOR_BASE);
920 }
921 
922 /* usb specific object needed to register this driver with the usb subsystem */
923 static struct usb_driver iowarrior_driver = {
924 	.name = "iowarrior",
925 	.probe = iowarrior_probe,
926 	.disconnect = iowarrior_disconnect,
927 	.id_table = iowarrior_ids,
928 };
929 
930 module_usb_driver(iowarrior_driver);
931