xref: /openbmc/linux/drivers/usb/misc/iowarrior.c (revision 22246614)
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 static DEFINE_MUTEX(iowarrior_open_disc_lock);
70 
71 /*--------------*/
72 /*     data     */
73 /*--------------*/
74 
75 /* Structure to hold all of our device specific stuff */
76 struct iowarrior {
77 	struct mutex mutex;			/* locks this structure */
78 	struct usb_device *udev;		/* save off the usb device pointer */
79 	struct usb_interface *interface;	/* the interface for this device */
80 	unsigned char minor;			/* the starting minor number for this device */
81 	struct usb_endpoint_descriptor *int_out_endpoint;	/* endpoint for reading (needed for IOW56 only) */
82 	struct usb_endpoint_descriptor *int_in_endpoint;	/* endpoint for reading */
83 	struct urb *int_in_urb;		/* the urb for reading data */
84 	unsigned char *int_in_buffer;	/* buffer for data to be read */
85 	unsigned char serial_number;	/* to detect lost packages */
86 	unsigned char *read_queue;	/* size is MAX_INTERRUPT_BUFFER * packet size */
87 	wait_queue_head_t read_wait;
88 	wait_queue_head_t write_wait;	/* wait-queue for writing to the device */
89 	atomic_t write_busy;		/* number of write-urbs submitted */
90 	atomic_t read_idx;
91 	atomic_t intr_idx;
92 	spinlock_t intr_idx_lock;	/* protects intr_idx */
93 	atomic_t overflow_flag;		/* signals an index 'rollover' */
94 	int present;			/* this is 1 as long as the device is connected */
95 	int opened;			/* this is 1 if the device is currently open */
96 	char chip_serial[9];		/* the serial number string of the chip connected */
97 	int report_size;		/* number of bytes in a report */
98 	u16 product_id;
99 };
100 
101 /*--------------*/
102 /*    globals   */
103 /*--------------*/
104 
105 /*
106  *  USB spec identifies 5 second timeouts.
107  */
108 #define GET_TIMEOUT 5
109 #define USB_REQ_GET_REPORT  0x01
110 //#if 0
111 static int usb_get_report(struct usb_device *dev,
112 			  struct usb_host_interface *inter, unsigned char type,
113 			  unsigned char id, void *buf, int size)
114 {
115 	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
116 			       USB_REQ_GET_REPORT,
117 			       USB_DIR_IN | USB_TYPE_CLASS |
118 			       USB_RECIP_INTERFACE, (type << 8) + id,
119 			       inter->desc.bInterfaceNumber, buf, size,
120 			       GET_TIMEOUT*HZ);
121 }
122 //#endif
123 
124 #define USB_REQ_SET_REPORT 0x09
125 
126 static int usb_set_report(struct usb_interface *intf, unsigned char type,
127 			  unsigned char id, void *buf, int size)
128 {
129 	return usb_control_msg(interface_to_usbdev(intf),
130 			       usb_sndctrlpipe(interface_to_usbdev(intf), 0),
131 			       USB_REQ_SET_REPORT,
132 			       USB_TYPE_CLASS | USB_RECIP_INTERFACE,
133 			       (type << 8) + id,
134 			       intf->cur_altsetting->desc.bInterfaceNumber, buf,
135 			       size, HZ);
136 }
137 
138 /*---------------------*/
139 /* driver registration */
140 /*---------------------*/
141 /* table of devices that work with this driver */
142 static struct usb_device_id iowarrior_ids[] = {
143 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW40)},
144 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW24)},
145 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV1)},
146 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV2)},
147 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW56)},
148 	{}			/* Terminating entry */
149 };
150 MODULE_DEVICE_TABLE(usb, iowarrior_ids);
151 
152 /*
153  * USB callback handler for reading data
154  */
155 static void iowarrior_callback(struct urb *urb)
156 {
157 	struct iowarrior *dev = urb->context;
158 	int intr_idx;
159 	int read_idx;
160 	int aux_idx;
161 	int offset;
162 	int status = urb->status;
163 	int retval;
164 
165 	switch (status) {
166 	case 0:
167 		/* success */
168 		break;
169 	case -ECONNRESET:
170 	case -ENOENT:
171 	case -ESHUTDOWN:
172 		return;
173 	default:
174 		goto exit;
175 	}
176 
177 	spin_lock(&dev->intr_idx_lock);
178 	intr_idx = atomic_read(&dev->intr_idx);
179 	/* aux_idx become previous intr_idx */
180 	aux_idx = (intr_idx == 0) ? (MAX_INTERRUPT_BUFFER - 1) : (intr_idx - 1);
181 	read_idx = atomic_read(&dev->read_idx);
182 
183 	/* queue is not empty and it's interface 0 */
184 	if ((intr_idx != read_idx)
185 	    && (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0)) {
186 		/* + 1 for serial number */
187 		offset = aux_idx * (dev->report_size + 1);
188 		if (!memcmp
189 		    (dev->read_queue + offset, urb->transfer_buffer,
190 		     dev->report_size)) {
191 			/* equal values on interface 0 will be ignored */
192 			spin_unlock(&dev->intr_idx_lock);
193 			goto exit;
194 		}
195 	}
196 
197 	/* aux_idx become next intr_idx */
198 	aux_idx = (intr_idx == (MAX_INTERRUPT_BUFFER - 1)) ? 0 : (intr_idx + 1);
199 	if (read_idx == aux_idx) {
200 		/* queue full, dropping oldest input */
201 		read_idx = (++read_idx == MAX_INTERRUPT_BUFFER) ? 0 : read_idx;
202 		atomic_set(&dev->read_idx, read_idx);
203 		atomic_set(&dev->overflow_flag, 1);
204 	}
205 
206 	/* +1 for serial number */
207 	offset = intr_idx * (dev->report_size + 1);
208 	memcpy(dev->read_queue + offset, urb->transfer_buffer,
209 	       dev->report_size);
210 	*(dev->read_queue + offset + (dev->report_size)) = dev->serial_number++;
211 
212 	atomic_set(&dev->intr_idx, aux_idx);
213 	spin_unlock(&dev->intr_idx_lock);
214 	/* tell the blocking read about the new data */
215 	wake_up_interruptible(&dev->read_wait);
216 
217 exit:
218 	retval = usb_submit_urb(urb, GFP_ATOMIC);
219 	if (retval)
220 		dev_err(&dev->interface->dev, "%s - usb_submit_urb failed with result %d\n",
221 			__func__, retval);
222 
223 }
224 
225 /*
226  * USB Callback handler for write-ops
227  */
228 static void iowarrior_write_callback(struct urb *urb)
229 {
230 	struct iowarrior *dev;
231 	int status = urb->status;
232 
233 	dev = urb->context;
234 	/* sync/async unlink faults aren't errors */
235 	if (status &&
236 	    !(status == -ENOENT ||
237 	      status == -ECONNRESET || status == -ESHUTDOWN)) {
238 		dbg("%s - nonzero write bulk status received: %d",
239 		    __func__, status);
240 	}
241 	/* free up our allocated buffer */
242 	usb_buffer_free(urb->dev, urb->transfer_buffer_length,
243 			urb->transfer_buffer, urb->transfer_dma);
244 	/* tell a waiting writer the interrupt-out-pipe is available again */
245 	atomic_dec(&dev->write_busy);
246 	wake_up_interruptible(&dev->write_wait);
247 }
248 
249 /**
250  *	iowarrior_delete
251  */
252 static inline void iowarrior_delete(struct iowarrior *dev)
253 {
254 	dbg("%s - minor %d", __func__, dev->minor);
255 	kfree(dev->int_in_buffer);
256 	usb_free_urb(dev->int_in_urb);
257 	kfree(dev->read_queue);
258 	kfree(dev);
259 }
260 
261 /*---------------------*/
262 /* fops implementation */
263 /*---------------------*/
264 
265 static int read_index(struct iowarrior *dev)
266 {
267 	int intr_idx, read_idx;
268 
269 	read_idx = atomic_read(&dev->read_idx);
270 	intr_idx = atomic_read(&dev->intr_idx);
271 
272 	return (read_idx == intr_idx ? -1 : read_idx);
273 }
274 
275 /**
276  *  iowarrior_read
277  */
278 static ssize_t iowarrior_read(struct file *file, char __user *buffer,
279 			      size_t count, loff_t *ppos)
280 {
281 	struct iowarrior *dev;
282 	int read_idx;
283 	int offset;
284 
285 	dev = (struct iowarrior *)file->private_data;
286 
287 	/* verify that the device wasn't unplugged */
288 	if (dev == NULL || !dev->present)
289 		return -ENODEV;
290 
291 	dbg("%s - minor %d, count = %zd", __func__, dev->minor, count);
292 
293 	/* read count must be packet size (+ time stamp) */
294 	if ((count != dev->report_size)
295 	    && (count != (dev->report_size + 1)))
296 		return -EINVAL;
297 
298 	/* repeat until no buffer overrun in callback handler occur */
299 	do {
300 		atomic_set(&dev->overflow_flag, 0);
301 		if ((read_idx = read_index(dev)) == -1) {
302 			/* queue emty */
303 			if (file->f_flags & O_NONBLOCK)
304 				return -EAGAIN;
305 			else {
306 				//next line will return when there is either new data, or the device is unplugged
307 				int r = wait_event_interruptible(dev->read_wait,
308 								 (!dev->present
309 								  || (read_idx =
310 								      read_index
311 								      (dev)) !=
312 								  -1));
313 				if (r) {
314 					//we were interrupted by a signal
315 					return -ERESTART;
316 				}
317 				if (!dev->present) {
318 					//The device was unplugged
319 					return -ENODEV;
320 				}
321 				if (read_idx == -1) {
322 					// Can this happen ???
323 					return 0;
324 				}
325 			}
326 		}
327 
328 		offset = read_idx * (dev->report_size + 1);
329 		if (copy_to_user(buffer, dev->read_queue + offset, count)) {
330 			return -EFAULT;
331 		}
332 	} while (atomic_read(&dev->overflow_flag));
333 
334 	read_idx = ++read_idx == MAX_INTERRUPT_BUFFER ? 0 : read_idx;
335 	atomic_set(&dev->read_idx, read_idx);
336 	return count;
337 }
338 
339 /*
340  * iowarrior_write
341  */
342 static ssize_t iowarrior_write(struct file *file,
343 			       const char __user *user_buffer,
344 			       size_t count, loff_t *ppos)
345 {
346 	struct iowarrior *dev;
347 	int retval = 0;
348 	char *buf = NULL;	/* for IOW24 and IOW56 we need a buffer */
349 	struct urb *int_out_urb = NULL;
350 
351 	dev = (struct iowarrior *)file->private_data;
352 
353 	mutex_lock(&dev->mutex);
354 	/* verify that the device wasn't unplugged */
355 	if (!dev->present) {
356 		retval = -ENODEV;
357 		goto exit;
358 	}
359 	dbg("%s - minor %d, count = %zd", __func__, dev->minor, count);
360 	/* if count is 0 we're already done */
361 	if (count == 0) {
362 		retval = 0;
363 		goto exit;
364 	}
365 	/* We only accept full reports */
366 	if (count != dev->report_size) {
367 		retval = -EINVAL;
368 		goto exit;
369 	}
370 	switch (dev->product_id) {
371 	case USB_DEVICE_ID_CODEMERCS_IOW24:
372 	case USB_DEVICE_ID_CODEMERCS_IOWPV1:
373 	case USB_DEVICE_ID_CODEMERCS_IOWPV2:
374 	case USB_DEVICE_ID_CODEMERCS_IOW40:
375 		/* IOW24 and IOW40 use a synchronous call */
376 		buf = kmalloc(8, GFP_KERNEL);	/* 8 bytes are enough for both products */
377 		if (!buf) {
378 			retval = -ENOMEM;
379 			goto exit;
380 		}
381 		if (copy_from_user(buf, user_buffer, count)) {
382 			retval = -EFAULT;
383 			kfree(buf);
384 			goto exit;
385 		}
386 		retval = usb_set_report(dev->interface, 2, 0, buf, count);
387 		kfree(buf);
388 		goto exit;
389 		break;
390 	case USB_DEVICE_ID_CODEMERCS_IOW56:
391 		/* The IOW56 uses asynchronous IO and more urbs */
392 		if (atomic_read(&dev->write_busy) == MAX_WRITES_IN_FLIGHT) {
393 			/* Wait until we are below the limit for submitted urbs */
394 			if (file->f_flags & O_NONBLOCK) {
395 				retval = -EAGAIN;
396 				goto exit;
397 			} else {
398 				retval = wait_event_interruptible(dev->write_wait,
399 								  (!dev->present || (atomic_read (&dev-> write_busy) < MAX_WRITES_IN_FLIGHT)));
400 				if (retval) {
401 					/* we were interrupted by a signal */
402 					retval = -ERESTART;
403 					goto exit;
404 				}
405 				if (!dev->present) {
406 					/* The device was unplugged */
407 					retval = -ENODEV;
408 					goto exit;
409 				}
410 				if (!dev->opened) {
411 					/* We were closed while waiting for an URB */
412 					retval = -ENODEV;
413 					goto exit;
414 				}
415 			}
416 		}
417 		atomic_inc(&dev->write_busy);
418 		int_out_urb = usb_alloc_urb(0, GFP_KERNEL);
419 		if (!int_out_urb) {
420 			retval = -ENOMEM;
421 			dbg("%s Unable to allocate urb ", __func__);
422 			goto error_no_urb;
423 		}
424 		buf = usb_buffer_alloc(dev->udev, dev->report_size,
425 				       GFP_KERNEL, &int_out_urb->transfer_dma);
426 		if (!buf) {
427 			retval = -ENOMEM;
428 			dbg("%s Unable to allocate buffer ", __func__);
429 			goto error_no_buffer;
430 		}
431 		usb_fill_int_urb(int_out_urb, dev->udev,
432 				 usb_sndintpipe(dev->udev,
433 						dev->int_out_endpoint->bEndpointAddress),
434 				 buf, dev->report_size,
435 				 iowarrior_write_callback, dev,
436 				 dev->int_out_endpoint->bInterval);
437 		int_out_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
438 		if (copy_from_user(buf, user_buffer, count)) {
439 			retval = -EFAULT;
440 			goto error;
441 		}
442 		retval = usb_submit_urb(int_out_urb, GFP_KERNEL);
443 		if (retval) {
444 			dbg("%s submit error %d for urb nr.%d", __func__,
445 			    retval, atomic_read(&dev->write_busy));
446 			goto error;
447 		}
448 		/* submit was ok */
449 		retval = count;
450 		usb_free_urb(int_out_urb);
451 		goto exit;
452 		break;
453 	default:
454 		/* what do we have here ? An unsupported Product-ID ? */
455 		dev_err(&dev->interface->dev, "%s - not supported for product=0x%x\n",
456 			__func__, dev->product_id);
457 		retval = -EFAULT;
458 		goto exit;
459 		break;
460 	}
461 error:
462 	usb_buffer_free(dev->udev, dev->report_size, buf,
463 			int_out_urb->transfer_dma);
464 error_no_buffer:
465 	usb_free_urb(int_out_urb);
466 error_no_urb:
467 	atomic_dec(&dev->write_busy);
468 	wake_up_interruptible(&dev->write_wait);
469 exit:
470 	mutex_unlock(&dev->mutex);
471 	return retval;
472 }
473 
474 /**
475  *	iowarrior_ioctl
476  */
477 static int iowarrior_ioctl(struct inode *inode, struct file *file,
478 			   unsigned int cmd, unsigned long arg)
479 {
480 	struct iowarrior *dev = NULL;
481 	__u8 *buffer;
482 	__u8 __user *user_buffer;
483 	int retval;
484 	int io_res;		/* checks for bytes read/written and copy_to/from_user results */
485 
486 	dev = (struct iowarrior *)file->private_data;
487 	if (dev == NULL) {
488 		return -ENODEV;
489 	}
490 
491 	buffer = kzalloc(dev->report_size, GFP_KERNEL);
492 	if (!buffer)
493 		return -ENOMEM;
494 
495 	/* lock this object */
496 	mutex_lock(&dev->mutex);
497 
498 	/* verify that the device wasn't unplugged */
499 	if (!dev->present) {
500 		retval = -ENODEV;
501 		goto error_out;
502 	}
503 
504 	dbg("%s - minor %d, cmd 0x%.4x, arg %ld", __func__, dev->minor, cmd,
505 	    arg);
506 
507 	retval = 0;
508 	io_res = 0;
509 	switch (cmd) {
510 	case IOW_WRITE:
511 		if (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW24 ||
512 		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV1 ||
513 		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV2 ||
514 		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW40) {
515 			user_buffer = (__u8 __user *)arg;
516 			io_res = copy_from_user(buffer, user_buffer,
517 						dev->report_size);
518 			if (io_res) {
519 				retval = -EFAULT;
520 			} else {
521 				io_res = usb_set_report(dev->interface, 2, 0,
522 							buffer,
523 							dev->report_size);
524 				if (io_res < 0)
525 					retval = io_res;
526 			}
527 		} else {
528 			retval = -EINVAL;
529 			dev_err(&dev->interface->dev,
530 				"ioctl 'IOW_WRITE' is not supported for product=0x%x.\n",
531 				dev->product_id);
532 		}
533 		break;
534 	case IOW_READ:
535 		user_buffer = (__u8 __user *)arg;
536 		io_res = usb_get_report(dev->udev,
537 					dev->interface->cur_altsetting, 1, 0,
538 					buffer, dev->report_size);
539 		if (io_res < 0)
540 			retval = io_res;
541 		else {
542 			io_res = copy_to_user(user_buffer, buffer, dev->report_size);
543 			if (io_res < 0)
544 				retval = -EFAULT;
545 		}
546 		break;
547 	case IOW_GETINFO:
548 		{
549 			/* Report available information for the device */
550 			struct iowarrior_info info;
551 			/* needed for power consumption */
552 			struct usb_config_descriptor *cfg_descriptor = &dev->udev->actconfig->desc;
553 
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 < 0)
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 	kfree(buffer);
588 	return retval;
589 }
590 
591 /**
592  *	iowarrior_open
593  */
594 static int iowarrior_open(struct inode *inode, struct file *file)
595 {
596 	struct iowarrior *dev = NULL;
597 	struct usb_interface *interface;
598 	int subminor;
599 	int retval = 0;
600 
601 	dbg("%s", __func__);
602 
603 	subminor = iminor(inode);
604 
605 	interface = usb_find_interface(&iowarrior_driver, subminor);
606 	if (!interface) {
607 		err("%s - error, can't find device for minor %d", __func__,
608 		    subminor);
609 		return -ENODEV;
610 	}
611 
612 	mutex_lock(&iowarrior_open_disc_lock);
613 	dev = usb_get_intfdata(interface);
614 	if (!dev) {
615 		mutex_unlock(&iowarrior_open_disc_lock);
616 		return -ENODEV;
617 	}
618 
619 	mutex_lock(&dev->mutex);
620 	mutex_unlock(&iowarrior_open_disc_lock);
621 
622 	/* Only one process can open each device, no sharing. */
623 	if (dev->opened) {
624 		retval = -EBUSY;
625 		goto out;
626 	}
627 
628 	/* setup interrupt handler for receiving values */
629 	if ((retval = usb_submit_urb(dev->int_in_urb, GFP_KERNEL)) < 0) {
630 		dev_err(&interface->dev, "Error %d while submitting URB\n", retval);
631 		retval = -EFAULT;
632 		goto out;
633 	}
634 	/* increment our usage count for the driver */
635 	++dev->opened;
636 	/* save our object in the file's private structure */
637 	file->private_data = dev;
638 	retval = 0;
639 
640 out:
641 	mutex_unlock(&dev->mutex);
642 	return retval;
643 }
644 
645 /**
646  *	iowarrior_release
647  */
648 static int iowarrior_release(struct inode *inode, struct file *file)
649 {
650 	struct iowarrior *dev;
651 	int retval = 0;
652 
653 	dev = (struct iowarrior *)file->private_data;
654 	if (dev == NULL) {
655 		return -ENODEV;
656 	}
657 
658 	dbg("%s - minor %d", __func__, dev->minor);
659 
660 	/* lock our device */
661 	mutex_lock(&dev->mutex);
662 
663 	if (dev->opened <= 0) {
664 		retval = -ENODEV;	/* close called more than once */
665 		mutex_unlock(&dev->mutex);
666 	} else {
667 		dev->opened = 0;	/* we're closeing now */
668 		retval = 0;
669 		if (dev->present) {
670 			/*
671 			   The device is still connected so we only shutdown
672 			   pending read-/write-ops.
673 			 */
674 			usb_kill_urb(dev->int_in_urb);
675 			wake_up_interruptible(&dev->read_wait);
676 			wake_up_interruptible(&dev->write_wait);
677 			mutex_unlock(&dev->mutex);
678 		} else {
679 			/* The device was unplugged, cleanup resources */
680 			mutex_unlock(&dev->mutex);
681 			iowarrior_delete(dev);
682 		}
683 	}
684 	return retval;
685 }
686 
687 static unsigned iowarrior_poll(struct file *file, poll_table * wait)
688 {
689 	struct iowarrior *dev = file->private_data;
690 	unsigned int mask = 0;
691 
692 	if (!dev->present)
693 		return POLLERR | POLLHUP;
694 
695 	poll_wait(file, &dev->read_wait, wait);
696 	poll_wait(file, &dev->write_wait, wait);
697 
698 	if (!dev->present)
699 		return POLLERR | POLLHUP;
700 
701 	if (read_index(dev) != -1)
702 		mask |= POLLIN | POLLRDNORM;
703 
704 	if (atomic_read(&dev->write_busy) < MAX_WRITES_IN_FLIGHT)
705 		mask |= POLLOUT | POLLWRNORM;
706 	return mask;
707 }
708 
709 /*
710  * File operations needed when we register this driver.
711  * This assumes that this driver NEEDS file operations,
712  * of course, which means that the driver is expected
713  * to have a node in the /dev directory. If the USB
714  * device were for a network interface then the driver
715  * would use "struct net_driver" instead, and a serial
716  * device would use "struct tty_driver".
717  */
718 static const struct file_operations iowarrior_fops = {
719 	.owner = THIS_MODULE,
720 	.write = iowarrior_write,
721 	.read = iowarrior_read,
722 	.ioctl = iowarrior_ioctl,
723 	.open = iowarrior_open,
724 	.release = iowarrior_release,
725 	.poll = iowarrior_poll,
726 };
727 
728 /*
729  * usb class driver info in order to get a minor number from the usb core,
730  * and to have the device registered with devfs and the driver core
731  */
732 static struct usb_class_driver iowarrior_class = {
733 	.name = "iowarrior%d",
734 	.fops = &iowarrior_fops,
735 	.minor_base = IOWARRIOR_MINOR_BASE,
736 };
737 
738 /*---------------------------------*/
739 /*  probe and disconnect functions */
740 /*---------------------------------*/
741 /**
742  *	iowarrior_probe
743  *
744  *	Called by the usb core when a new device is connected that it thinks
745  *	this driver might be interested in.
746  */
747 static int iowarrior_probe(struct usb_interface *interface,
748 			   const struct usb_device_id *id)
749 {
750 	struct usb_device *udev = interface_to_usbdev(interface);
751 	struct iowarrior *dev = NULL;
752 	struct usb_host_interface *iface_desc;
753 	struct usb_endpoint_descriptor *endpoint;
754 	int i;
755 	int retval = -ENOMEM;
756 
757 	/* allocate memory for our device state and intialize it */
758 	dev = kzalloc(sizeof(struct iowarrior), GFP_KERNEL);
759 	if (dev == NULL) {
760 		dev_err(&interface->dev, "Out of memory\n");
761 		return retval;
762 	}
763 
764 	mutex_init(&dev->mutex);
765 
766 	atomic_set(&dev->intr_idx, 0);
767 	atomic_set(&dev->read_idx, 0);
768 	spin_lock_init(&dev->intr_idx_lock);
769 	atomic_set(&dev->overflow_flag, 0);
770 	init_waitqueue_head(&dev->read_wait);
771 	atomic_set(&dev->write_busy, 0);
772 	init_waitqueue_head(&dev->write_wait);
773 
774 	dev->udev = udev;
775 	dev->interface = interface;
776 
777 	iface_desc = interface->cur_altsetting;
778 	dev->product_id = le16_to_cpu(udev->descriptor.idProduct);
779 
780 	/* set up the endpoint information */
781 	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
782 		endpoint = &iface_desc->endpoint[i].desc;
783 
784 		if (usb_endpoint_is_int_in(endpoint))
785 			dev->int_in_endpoint = endpoint;
786 		if (usb_endpoint_is_int_out(endpoint))
787 			/* this one will match for the IOWarrior56 only */
788 			dev->int_out_endpoint = endpoint;
789 	}
790 	/* we have to check the report_size often, so remember it in the endianess suitable for our machine */
791 	dev->report_size = le16_to_cpu(dev->int_in_endpoint->wMaxPacketSize);
792 	if ((dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) &&
793 	    (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW56))
794 		/* IOWarrior56 has wMaxPacketSize different from report size */
795 		dev->report_size = 7;
796 
797 	/* create the urb and buffer for reading */
798 	dev->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);
799 	if (!dev->int_in_urb) {
800 		dev_err(&interface->dev, "Couldn't allocate interrupt_in_urb\n");
801 		goto error;
802 	}
803 	dev->int_in_buffer = kmalloc(dev->report_size, GFP_KERNEL);
804 	if (!dev->int_in_buffer) {
805 		dev_err(&interface->dev, "Couldn't allocate int_in_buffer\n");
806 		goto error;
807 	}
808 	usb_fill_int_urb(dev->int_in_urb, dev->udev,
809 			 usb_rcvintpipe(dev->udev,
810 					dev->int_in_endpoint->bEndpointAddress),
811 			 dev->int_in_buffer, dev->report_size,
812 			 iowarrior_callback, dev,
813 			 dev->int_in_endpoint->bInterval);
814 	/* create an internal buffer for interrupt data from the device */
815 	dev->read_queue =
816 	    kmalloc(((dev->report_size + 1) * MAX_INTERRUPT_BUFFER),
817 		    GFP_KERNEL);
818 	if (!dev->read_queue) {
819 		dev_err(&interface->dev, "Couldn't allocate read_queue\n");
820 		goto error;
821 	}
822 	/* Get the serial-number of the chip */
823 	memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
824 	usb_string(udev, udev->descriptor.iSerialNumber, dev->chip_serial,
825 		   sizeof(dev->chip_serial));
826 	if (strlen(dev->chip_serial) != 8)
827 		memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
828 
829 	/* Set the idle timeout to 0, if this is interface 0 */
830 	if (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) {
831 	    usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
832 			    0x0A,
833 			    USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0,
834 			    0, NULL, 0, USB_CTRL_SET_TIMEOUT);
835 	}
836 	/* allow device read and ioctl */
837 	dev->present = 1;
838 
839 	/* we can register the device now, as it is ready */
840 	usb_set_intfdata(interface, dev);
841 
842 	retval = usb_register_dev(interface, &iowarrior_class);
843 	if (retval) {
844 		/* something prevented us from registering this driver */
845 		dev_err(&interface->dev, "Not able to get a minor for this device.\n");
846 		usb_set_intfdata(interface, NULL);
847 		goto error;
848 	}
849 
850 	dev->minor = interface->minor;
851 
852 	/* let the user know what node this device is now attached to */
853 	dev_info(&interface->dev, "IOWarrior product=0x%x, serial=%s interface=%d "
854 		 "now attached to iowarrior%d\n", dev->product_id, dev->chip_serial,
855 		 iface_desc->desc.bInterfaceNumber, dev->minor - IOWARRIOR_MINOR_BASE);
856 	return retval;
857 
858 error:
859 	iowarrior_delete(dev);
860 	return retval;
861 }
862 
863 /**
864  *	iowarrior_disconnect
865  *
866  *	Called by the usb core when the device is removed from the system.
867  */
868 static void iowarrior_disconnect(struct usb_interface *interface)
869 {
870 	struct iowarrior *dev;
871 	int minor;
872 
873 	dev = usb_get_intfdata(interface);
874 	mutex_lock(&iowarrior_open_disc_lock);
875 	usb_set_intfdata(interface, NULL);
876 
877 	minor = dev->minor;
878 
879 	/* give back our minor */
880 	usb_deregister_dev(interface, &iowarrior_class);
881 
882 	mutex_lock(&dev->mutex);
883 
884 	/* prevent device read, write and ioctl */
885 	dev->present = 0;
886 
887 	mutex_unlock(&dev->mutex);
888 	mutex_unlock(&iowarrior_open_disc_lock);
889 
890 	if (dev->opened) {
891 		/* There is a process that holds a filedescriptor to the device ,
892 		   so we only shutdown read-/write-ops going on.
893 		   Deleting the device is postponed until close() was called.
894 		 */
895 		usb_kill_urb(dev->int_in_urb);
896 		wake_up_interruptible(&dev->read_wait);
897 		wake_up_interruptible(&dev->write_wait);
898 	} else {
899 		/* no process is using the device, cleanup now */
900 		iowarrior_delete(dev);
901 	}
902 
903 	dev_info(&interface->dev, "I/O-Warror #%d now disconnected\n",
904 		 minor - IOWARRIOR_MINOR_BASE);
905 }
906 
907 /* usb specific object needed to register this driver with the usb subsystem */
908 static struct usb_driver iowarrior_driver = {
909 	.name = "iowarrior",
910 	.probe = iowarrior_probe,
911 	.disconnect = iowarrior_disconnect,
912 	.id_table = iowarrior_ids,
913 };
914 
915 static int __init iowarrior_init(void)
916 {
917 	return usb_register(&iowarrior_driver);
918 }
919 
920 static void __exit iowarrior_exit(void)
921 {
922 	usb_deregister(&iowarrior_driver);
923 }
924 
925 module_init(iowarrior_init);
926 module_exit(iowarrior_exit);
927