xref: /linux/drivers/usb/image/mdc800.c (revision 30e48a75df9c6ead93866bdf1511ca6ecfe17fbe)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * copyright (C) 1999/2000 by Henning Zabel <henning@uni-paderborn.de>
4  */
5 
6 
7 /*
8  *	USB-Kernel Driver for the Mustek MDC800 Digital Camera
9  *	(c) 1999/2000 Henning Zabel <henning@uni-paderborn.de>
10  *
11  *
12  * The driver brings the USB functions of the MDC800 to Linux.
13  * To use the Camera you must support the USB Protocol of the camera
14  * to the Kernel Node.
15  * The Driver uses a misc device Node. Create it with :
16  * mknod /dev/mustek c 180 32
17  *
18  * The driver supports only one camera.
19  *
20  * Fix: mdc800 used sleep_on and slept with io_lock held.
21  * Converted sleep_on to waitqueues with schedule_timeout and made io_lock
22  * a semaphore from a spinlock.
23  * by Oliver Neukum <oliver@neukum.name>
24  * (02/12/2001)
25  *
26  * Identify version on module load.
27  * (08/04/2001) gb
28  *
29  * version 0.7.5
30  * Fixed potential SMP races with Spinlocks.
31  * Thanks to Oliver Neukum <oliver@neukum.name> who
32  * noticed the race conditions.
33  * (30/10/2000)
34  *
35  * Fixed: Setting urb->dev before submitting urb.
36  * by Greg KH <greg@kroah.com>
37  * (13/10/2000)
38  *
39  * version 0.7.3
40  * bugfix : The mdc800->state field gets set to READY after the
41  * disconnect function sets it to NOT_CONNECTED. This makes the
42  * driver running like the camera is connected and causes some
43  * hang ups.
44  *
45  * version 0.7.1
46  * MOD_INC and MOD_DEC are changed in usb_probe to prevent load/unload
47  * problems when compiled as Module.
48  * (04/04/2000)
49  *
50  * The mdc800 driver gets assigned the USB Minor 32-47. The Registration
51  * was updated to use these values.
52  * (26/03/2000)
53  *
54  * The Init und Exit Module Function are updated.
55  * (01/03/2000)
56  *
57  * version 0.7.0
58  * Rewrite of the driver : The driver now uses URB's. The old stuff
59  * has been removed.
60  *
61  * version 0.6.0
62  * Rewrite of this driver: The Emulation of the rs232 protocoll
63  * has been removed from the driver. A special executeCommand function
64  * for this driver is included to gphoto.
65  * The driver supports two kind of communication to bulk endpoints.
66  * Either with the dev->bus->ops->bulk... or with callback function.
67  * (09/11/1999)
68  *
69  * version 0.5.0:
70  * first Version that gets a version number. Most of the needed
71  * functions work.
72  * (20/10/1999)
73  */
74 
75 #include <linux/sched/signal.h>
76 #include <linux/signal.h>
77 #include <linux/spinlock.h>
78 #include <linux/errno.h>
79 #include <linux/random.h>
80 #include <linux/poll.h>
81 #include <linux/init.h>
82 #include <linux/slab.h>
83 #include <linux/module.h>
84 #include <linux/wait.h>
85 #include <linux/mutex.h>
86 
87 #include <linux/usb.h>
88 #include <linux/fs.h>
89 
90 /*
91  * Version Information
92  */
93 #define DRIVER_VERSION "v0.7.5 (30/10/2000)"
94 #define DRIVER_AUTHOR "Henning Zabel <henning@uni-paderborn.de>"
95 #define DRIVER_DESC "USB Driver for Mustek MDC800 Digital Camera"
96 
97 /* Vendor and Product Information */
98 #define MDC800_VENDOR_ID 	0x055f
99 #define MDC800_PRODUCT_ID	0xa800
100 
101 /* Timeouts (msec) */
102 #define TO_DOWNLOAD_GET_READY		1500
103 #define TO_DOWNLOAD_GET_BUSY		1500
104 #define TO_WRITE_GET_READY		1000
105 #define TO_DEFAULT_COMMAND		5000
106 #define TO_READ_FROM_IRQ 		TO_DEFAULT_COMMAND
107 #define TO_GET_READY			TO_DEFAULT_COMMAND
108 
109 /* Minor Number of the device (create with mknod /dev/mustek c 180 32) */
110 #define MDC800_DEVICE_MINOR_BASE 32
111 
112 
113 /**************************************************************************
114 	Data and structs
115 ***************************************************************************/
116 
117 
118 typedef enum {
119 	NOT_CONNECTED, READY, WORKING, DOWNLOAD
120 } mdc800_state;
121 
122 
123 /* Data for the driver */
124 struct mdc800_data
125 {
126 	struct usb_device *	dev;			// Device Data
127 	mdc800_state 		state;
128 
129 	unsigned int		endpoint [4];
130 
131 	struct urb *		irq_urb;
132 	wait_queue_head_t	irq_wait;
133 	int			irq_woken;
134 	char*			irq_urb_buffer;
135 
136 	int			camera_busy;          // is camera busy ?
137 	int 			camera_request_ready; // Status to synchronize with irq
138 	char 			camera_response [8];  // last Bytes send after busy
139 
140 	struct urb *   		write_urb;
141 	char*			write_urb_buffer;
142 	wait_queue_head_t	write_wait;
143 	int			written;
144 
145 
146 	struct urb *   		download_urb;
147 	char*			download_urb_buffer;
148 	wait_queue_head_t	download_wait;
149 	int			downloaded;
150 	int			download_left;		// Bytes left to download ?
151 
152 
153 	/* Device Data */
154 	char			out [64];	// Answer Buffer
155 	int 			out_ptr;	// Index to the first not readen byte
156 	int			out_count;	// Bytes in the buffer
157 
158 	int			open;		// Camera device open ?
159 	struct mutex		io_lock;	// IO -lock
160 
161 	char 			in [8];		// Command Input Buffer
162 	int  			in_count;
163 
164 	int			pic_index;	// Cache for the Imagesize (-1 for nothing cached )
165 	int			pic_len;
166 	int			minor;
167 };
168 
169 
170 /* Specification of the Endpoints */
171 static struct usb_endpoint_descriptor mdc800_ed [4] =
172 {
173 	{
174 		.bLength = 		0,
175 		.bDescriptorType =	0,
176 		.bEndpointAddress =	0x01,
177 		.bmAttributes = 	0x02,
178 		.wMaxPacketSize =	cpu_to_le16(8),
179 		.bInterval = 		0,
180 		.bRefresh = 		0,
181 		.bSynchAddress = 	0,
182 	},
183 	{
184 		.bLength = 		0,
185 		.bDescriptorType = 	0,
186 		.bEndpointAddress = 	0x82,
187 		.bmAttributes = 	0x03,
188 		.wMaxPacketSize = 	cpu_to_le16(8),
189 		.bInterval = 		0,
190 		.bRefresh = 		0,
191 		.bSynchAddress = 	0,
192 	},
193 	{
194 		.bLength = 		0,
195 		.bDescriptorType = 	0,
196 		.bEndpointAddress = 	0x03,
197 		.bmAttributes = 	0x02,
198 		.wMaxPacketSize = 	cpu_to_le16(64),
199 		.bInterval = 		0,
200 		.bRefresh = 		0,
201 		.bSynchAddress = 	0,
202 	},
203 	{
204 		.bLength = 		0,
205 		.bDescriptorType = 	0,
206 		.bEndpointAddress = 	0x84,
207 		.bmAttributes = 	0x02,
208 		.wMaxPacketSize = 	cpu_to_le16(64),
209 		.bInterval = 		0,
210 		.bRefresh = 		0,
211 		.bSynchAddress = 	0,
212 	},
213 };
214 
215 /* The Variable used by the driver */
216 static struct mdc800_data* mdc800;
217 
218 
219 /***************************************************************************
220 	The USB Part of the driver
221 ****************************************************************************/
222 
223 static int mdc800_endpoint_equals (struct usb_endpoint_descriptor *a,struct usb_endpoint_descriptor *b)
224 {
225 	return (
226 		   ( a->bEndpointAddress == b->bEndpointAddress )
227 		&& ( a->bmAttributes     == b->bmAttributes     )
228 		&& ( a->wMaxPacketSize   == b->wMaxPacketSize   )
229 	);
230 }
231 
232 
233 /*
234  * Checks whether the camera responds busy
235  */
236 static int mdc800_isBusy (char* ch)
237 {
238 	int i=0;
239 	while (i<8)
240 	{
241 		if (ch [i] != (char)0x99)
242 			return 0;
243 		i++;
244 	}
245 	return 1;
246 }
247 
248 
249 /*
250  * Checks whether the Camera is ready
251  */
252 static int mdc800_isReady (char *ch)
253 {
254 	int i=0;
255 	while (i<8)
256 	{
257 		if (ch [i] != (char)0xbb)
258 			return 0;
259 		i++;
260 	}
261 	return 1;
262 }
263 
264 
265 
266 /*
267  * USB IRQ Handler for InputLine
268  */
269 static void mdc800_usb_irq (struct urb *urb)
270 {
271 	int data_received=0, wake_up;
272 	unsigned char* b=urb->transfer_buffer;
273 	struct mdc800_data* mdc800=urb->context;
274 	struct device *dev = &mdc800->dev->dev;
275 	int status = urb->status;
276 
277 	if (status >= 0) {
278 		if (mdc800_isBusy (b))
279 		{
280 			if (!mdc800->camera_busy)
281 			{
282 				mdc800->camera_busy=1;
283 				dev_dbg(dev, "gets busy\n");
284 			}
285 		}
286 		else
287 		{
288 			if (mdc800->camera_busy && mdc800_isReady (b))
289 			{
290 				mdc800->camera_busy=0;
291 				dev_dbg(dev, "gets ready\n");
292 			}
293 		}
294 		if (!(mdc800_isBusy (b) || mdc800_isReady (b)))
295 		{
296 			/* Store Data in camera_answer field */
297 			dev_dbg(dev, "%i %i %i %i %i %i %i %i \n",b[0],b[1],b[2],b[3],b[4],b[5],b[6],b[7]);
298 
299 			memcpy (mdc800->camera_response,b,8);
300 			data_received=1;
301 		}
302 	}
303 	wake_up= ( mdc800->camera_request_ready > 0 )
304 		&&
305 		(
306 			((mdc800->camera_request_ready == 1) && (!mdc800->camera_busy))
307 		||
308 			((mdc800->camera_request_ready == 2) && data_received)
309 		||
310 			((mdc800->camera_request_ready == 3) && (mdc800->camera_busy))
311 		||
312 			(status < 0)
313 		);
314 
315 	if (wake_up)
316 	{
317 		mdc800->camera_request_ready=0;
318 		mdc800->irq_woken=1;
319 		wake_up (&mdc800->irq_wait);
320 	}
321 }
322 
323 
324 /*
325  * Waits a while until the irq responds that camera is ready
326  *
327  *  mode : 0: Wait for camera gets ready
328  *         1: Wait for receiving data
329  *         2: Wait for camera gets busy
330  *
331  * msec: Time to wait
332  */
333 static int mdc800_usb_waitForIRQ (int mode, int msec)
334 {
335 	mdc800->camera_request_ready=1+mode;
336 
337 	wait_event_timeout(mdc800->irq_wait, mdc800->irq_woken,
338 			   msecs_to_jiffies(msec));
339 	mdc800->irq_woken = 0;
340 
341 	if (mdc800->camera_request_ready>0)
342 	{
343 		mdc800->camera_request_ready=0;
344 		dev_err(&mdc800->dev->dev, "timeout waiting for camera.\n");
345 		return -1;
346 	}
347 
348 	if (mdc800->state == NOT_CONNECTED)
349 	{
350 		printk(KERN_WARNING "mdc800: Camera gets disconnected "
351 		       "during waiting for irq.\n");
352 		mdc800->camera_request_ready=0;
353 		return -2;
354 	}
355 
356 	return 0;
357 }
358 
359 
360 /*
361  * The write_urb callback function
362  */
363 static void mdc800_usb_write_notify (struct urb *urb)
364 {
365 	struct mdc800_data* mdc800=urb->context;
366 	int status = urb->status;
367 
368 	if (status != 0)
369 		dev_err(&mdc800->dev->dev,
370 			"writing command fails (status=%i)\n", status);
371 	else
372 		mdc800->state=READY;
373 	mdc800->written = 1;
374 	wake_up (&mdc800->write_wait);
375 }
376 
377 
378 /*
379  * The download_urb callback function
380  */
381 static void mdc800_usb_download_notify (struct urb *urb)
382 {
383 	struct mdc800_data* mdc800=urb->context;
384 	int status = urb->status;
385 
386 	if (status == 0) {
387 		/* Fill output buffer with these data */
388 		memcpy (mdc800->out,  urb->transfer_buffer, 64);
389 		mdc800->out_count=64;
390 		mdc800->out_ptr=0;
391 		mdc800->download_left-=64;
392 		if (mdc800->download_left == 0)
393 		{
394 			mdc800->state=READY;
395 		}
396 	} else {
397 		dev_err(&mdc800->dev->dev,
398 			"request bytes fails (status:%i)\n", status);
399 	}
400 	mdc800->downloaded = 1;
401 	wake_up (&mdc800->download_wait);
402 }
403 
404 
405 /***************************************************************************
406 	Probing for the Camera
407  ***************************************************************************/
408 
409 static struct usb_driver mdc800_usb_driver;
410 static const struct file_operations mdc800_device_ops;
411 static struct usb_class_driver mdc800_class = {
412 	.name =		"mdc800%d",
413 	.fops =		&mdc800_device_ops,
414 	.minor_base =	MDC800_DEVICE_MINOR_BASE,
415 };
416 
417 
418 /*
419  * Callback to search the Mustek MDC800 on the USB Bus
420  */
421 static int mdc800_usb_probe (struct usb_interface *intf,
422 			       const struct usb_device_id *id)
423 {
424 	int i,j;
425 	struct usb_host_interface *intf_desc;
426 	struct usb_device *dev = interface_to_usbdev (intf);
427 	int irq_interval=0;
428 	int retval;
429 
430 	dev_dbg(&intf->dev, "(%s) called.\n", __func__);
431 
432 
433 	if (mdc800->dev != NULL)
434 	{
435 		dev_warn(&intf->dev, "only one Mustek MDC800 is supported.\n");
436 		return -ENODEV;
437 	}
438 
439 	if (dev->descriptor.bNumConfigurations != 1)
440 	{
441 		dev_err(&intf->dev,
442 			"probe fails -> wrong Number of Configuration\n");
443 		return -ENODEV;
444 	}
445 	intf_desc = intf->cur_altsetting;
446 
447 	if (
448 			( intf_desc->desc.bInterfaceClass != 0xff )
449 		||	( intf_desc->desc.bInterfaceSubClass != 0 )
450 		|| ( intf_desc->desc.bInterfaceProtocol != 0 )
451 		|| ( intf_desc->desc.bNumEndpoints != 4)
452 	)
453 	{
454 		dev_err(&intf->dev, "probe fails -> wrong Interface\n");
455 		return -ENODEV;
456 	}
457 
458 	/* Check the Endpoints */
459 	for (i=0; i<4; i++)
460 	{
461 		mdc800->endpoint[i]=-1;
462 		for (j=0; j<4; j++)
463 		{
464 			if (mdc800_endpoint_equals (&intf_desc->endpoint [j].desc,&mdc800_ed [i]))
465 			{
466 				mdc800->endpoint[i]=intf_desc->endpoint [j].desc.bEndpointAddress ;
467 				if (i==1)
468 				{
469 					irq_interval=intf_desc->endpoint [j].desc.bInterval;
470 				}
471 			}
472 		}
473 		if (mdc800->endpoint[i] == -1)
474 		{
475 			dev_err(&intf->dev, "probe fails -> Wrong Endpoints.\n");
476 			return -ENODEV;
477 		}
478 	}
479 
480 
481 	dev_info(&intf->dev, "Found Mustek MDC800 on USB.\n");
482 
483 	mutex_lock(&mdc800->io_lock);
484 
485 	retval = usb_register_dev(intf, &mdc800_class);
486 	if (retval) {
487 		dev_err(&intf->dev, "Not able to get a minor for this device.\n");
488 		mutex_unlock(&mdc800->io_lock);
489 		return -ENODEV;
490 	}
491 
492 	mdc800->dev=dev;
493 	mdc800->open=0;
494 
495 	/* Setup URB Structs */
496 	usb_fill_int_urb (
497 		mdc800->irq_urb,
498 		mdc800->dev,
499 		usb_rcvintpipe (mdc800->dev,mdc800->endpoint [1]),
500 		mdc800->irq_urb_buffer,
501 		8,
502 		mdc800_usb_irq,
503 		mdc800,
504 		irq_interval
505 	);
506 
507 	usb_fill_bulk_urb (
508 		mdc800->write_urb,
509 		mdc800->dev,
510 		usb_sndbulkpipe (mdc800->dev, mdc800->endpoint[0]),
511 		mdc800->write_urb_buffer,
512 		8,
513 		mdc800_usb_write_notify,
514 		mdc800
515 	);
516 
517 	usb_fill_bulk_urb (
518 		mdc800->download_urb,
519 		mdc800->dev,
520 		usb_rcvbulkpipe (mdc800->dev, mdc800->endpoint [3]),
521 		mdc800->download_urb_buffer,
522 		64,
523 		mdc800_usb_download_notify,
524 		mdc800
525 	);
526 
527 	mdc800->state=READY;
528 
529 	mutex_unlock(&mdc800->io_lock);
530 
531 	usb_set_intfdata(intf, mdc800);
532 	return 0;
533 }
534 
535 
536 /*
537  * Disconnect USB device (maybe the MDC800)
538  */
539 static void mdc800_usb_disconnect (struct usb_interface *intf)
540 {
541 	struct mdc800_data* mdc800 = usb_get_intfdata(intf);
542 
543 	dev_dbg(&intf->dev, "(%s) called\n", __func__);
544 
545 	if (mdc800) {
546 		if (mdc800->state == NOT_CONNECTED)
547 			return;
548 
549 		usb_deregister_dev(intf, &mdc800_class);
550 
551 		/* must be under lock to make sure no URB
552 		   is submitted after usb_kill_urb() */
553 		mutex_lock(&mdc800->io_lock);
554 		mdc800->state=NOT_CONNECTED;
555 
556 		usb_kill_urb(mdc800->irq_urb);
557 		usb_kill_urb(mdc800->write_urb);
558 		usb_kill_urb(mdc800->download_urb);
559 		mutex_unlock(&mdc800->io_lock);
560 
561 		mdc800->dev = NULL;
562 		usb_set_intfdata(intf, NULL);
563 	}
564 	dev_info(&intf->dev, "Mustek MDC800 disconnected from USB.\n");
565 }
566 
567 
568 /***************************************************************************
569 	The Misc device Part (file_operations)
570 ****************************************************************************/
571 
572 /*
573  * This Function calc the Answersize for a command.
574  */
575 static int mdc800_getAnswerSize (char command)
576 {
577 	switch ((unsigned char) command)
578 	{
579 		case 0x2a:
580 		case 0x49:
581 		case 0x51:
582 		case 0x0d:
583 		case 0x20:
584 		case 0x07:
585 		case 0x01:
586 		case 0x25:
587 		case 0x00:
588 			return 8;
589 
590 		case 0x05:
591 		case 0x3e:
592 			return mdc800->pic_len;
593 
594 		case 0x09:
595 			return 4096;
596 
597 		default:
598 			return 0;
599 	}
600 }
601 
602 
603 /*
604  * Init the device: (1) alloc mem (2) Increase MOD Count ..
605  */
606 static int mdc800_device_open (struct inode* inode, struct file *file)
607 {
608 	int retval=0;
609 	int errn=0;
610 
611 	mutex_lock(&mdc800->io_lock);
612 
613 	if (mdc800->state == NOT_CONNECTED)
614 	{
615 		errn=-EBUSY;
616 		goto error_out;
617 	}
618 	if (mdc800->open)
619 	{
620 		errn=-EBUSY;
621 		goto error_out;
622 	}
623 
624 	mdc800->in_count=0;
625 	mdc800->out_count=0;
626 	mdc800->out_ptr=0;
627 	mdc800->pic_index=0;
628 	mdc800->pic_len=-1;
629 	mdc800->download_left=0;
630 
631 	mdc800->camera_busy=0;
632 	mdc800->camera_request_ready=0;
633 
634 	mdc800->irq_urb->dev = mdc800->dev;
635 	retval = usb_submit_urb (mdc800->irq_urb, GFP_KERNEL);
636 	if (retval) {
637 		dev_err(&mdc800->dev->dev,
638 			"request USB irq fails (submit_retval=%i).\n", retval);
639 		errn = -EIO;
640 		goto error_out;
641 	}
642 
643 	mdc800->open=1;
644 	dev_dbg(&mdc800->dev->dev, "Mustek MDC800 device opened.\n");
645 
646 error_out:
647 	mutex_unlock(&mdc800->io_lock);
648 	return errn;
649 }
650 
651 
652 /*
653  * Close the Camera and release Memory
654  */
655 static int mdc800_device_release (struct inode* inode, struct file *file)
656 {
657 	int retval=0;
658 
659 	mutex_lock(&mdc800->io_lock);
660 	if (mdc800->open && (mdc800->state != NOT_CONNECTED))
661 	{
662 		usb_kill_urb(mdc800->irq_urb);
663 		usb_kill_urb(mdc800->write_urb);
664 		usb_kill_urb(mdc800->download_urb);
665 		mdc800->open=0;
666 	}
667 	else
668 	{
669 		retval=-EIO;
670 	}
671 
672 	mutex_unlock(&mdc800->io_lock);
673 	return retval;
674 }
675 
676 
677 /*
678  * The Device read callback Function
679  */
680 static ssize_t mdc800_device_read (struct file *file, char __user *buf, size_t len, loff_t *pos)
681 {
682 	size_t left=len, sts=len; /* single transfer size */
683 	char __user *ptr = buf;
684 	int retval;
685 
686 	mutex_lock(&mdc800->io_lock);
687 	if (mdc800->state == NOT_CONNECTED)
688 	{
689 		mutex_unlock(&mdc800->io_lock);
690 		return -EBUSY;
691 	}
692 	if (mdc800->state == WORKING)
693 	{
694 		printk(KERN_WARNING "mdc800: Illegal State \"working\""
695 		       "reached during read ?!\n");
696 		mutex_unlock(&mdc800->io_lock);
697 		return -EBUSY;
698 	}
699 	if (!mdc800->open)
700 	{
701 		mutex_unlock(&mdc800->io_lock);
702 		return -EBUSY;
703 	}
704 
705 	while (left)
706 	{
707 		if (signal_pending (current))
708 		{
709 			mutex_unlock(&mdc800->io_lock);
710 			return -EINTR;
711 		}
712 
713 		sts=left > (mdc800->out_count-mdc800->out_ptr)?mdc800->out_count-mdc800->out_ptr:left;
714 
715 		if (sts <= 0)
716 		{
717 			/* Too less Data in buffer */
718 			if (mdc800->state == DOWNLOAD)
719 			{
720 				mdc800->out_count=0;
721 				mdc800->out_ptr=0;
722 
723 				/* Download -> Request new bytes */
724 				mdc800->download_urb->dev = mdc800->dev;
725 				retval = usb_submit_urb (mdc800->download_urb, GFP_KERNEL);
726 				if (retval) {
727 					dev_err(&mdc800->dev->dev,
728 						"Can't submit download urb "
729 						"(retval=%i)\n", retval);
730 					mutex_unlock(&mdc800->io_lock);
731 					return len-left;
732 				}
733 				wait_event_timeout(mdc800->download_wait,
734 				     mdc800->downloaded,
735 				     msecs_to_jiffies(TO_DOWNLOAD_GET_READY));
736 				mdc800->downloaded = 0;
737 				if (mdc800->download_urb->status != 0)
738 				{
739 					dev_err(&mdc800->dev->dev,
740 						"request download-bytes fails "
741 						"(status=%i)\n",
742 						mdc800->download_urb->status);
743 					mutex_unlock(&mdc800->io_lock);
744 					return len-left;
745 				}
746 			}
747 			else
748 			{
749 				/* No more bytes -> that's an error*/
750 				mutex_unlock(&mdc800->io_lock);
751 				return -EIO;
752 			}
753 		}
754 		else
755 		{
756 			/* Copy Bytes */
757 			if (copy_to_user(ptr, &mdc800->out [mdc800->out_ptr],
758 						sts)) {
759 				mutex_unlock(&mdc800->io_lock);
760 				return -EFAULT;
761 			}
762 			ptr+=sts;
763 			left-=sts;
764 			mdc800->out_ptr+=sts;
765 		}
766 	}
767 
768 	mutex_unlock(&mdc800->io_lock);
769 	return len-left;
770 }
771 
772 
773 /*
774  * The Device write callback Function
775  * If a 8Byte Command is received, it will be send to the camera.
776  * After this the driver initiates the request for the answer or
777  * just waits until the camera becomes ready.
778  */
779 static ssize_t mdc800_device_write (struct file *file, const char __user *buf, size_t len, loff_t *pos)
780 {
781 	size_t i=0;
782 	int retval;
783 
784 	mutex_lock(&mdc800->io_lock);
785 	if (mdc800->state != READY)
786 	{
787 		mutex_unlock(&mdc800->io_lock);
788 		return -EBUSY;
789 	}
790 	if (!mdc800->open )
791 	{
792 		mutex_unlock(&mdc800->io_lock);
793 		return -EBUSY;
794 	}
795 
796 	while (i<len)
797 	{
798 		unsigned char c;
799 		if (signal_pending (current))
800 		{
801 			mutex_unlock(&mdc800->io_lock);
802 			return -EINTR;
803 		}
804 
805 		if(get_user(c, buf+i))
806 		{
807 			mutex_unlock(&mdc800->io_lock);
808 			return -EFAULT;
809 		}
810 
811 		/* check for command start */
812 		if (c == 0x55)
813 		{
814 			mdc800->in_count=0;
815 			mdc800->out_count=0;
816 			mdc800->out_ptr=0;
817 			mdc800->download_left=0;
818 		}
819 
820 		/* save command byte */
821 		if (mdc800->in_count < 8)
822 		{
823 			mdc800->in[mdc800->in_count] = c;
824 			mdc800->in_count++;
825 		}
826 		else
827 		{
828 			mutex_unlock(&mdc800->io_lock);
829 			return -EIO;
830 		}
831 
832 		/* Command Buffer full ? -> send it to camera */
833 		if (mdc800->in_count == 8)
834 		{
835 			int answersize;
836 
837 			if (mdc800_usb_waitForIRQ (0,TO_GET_READY))
838 			{
839 				dev_err(&mdc800->dev->dev,
840 					"Camera didn't get ready.\n");
841 				mutex_unlock(&mdc800->io_lock);
842 				return -EIO;
843 			}
844 
845 			answersize=mdc800_getAnswerSize (mdc800->in[1]);
846 
847 			mdc800->state=WORKING;
848 			memcpy (mdc800->write_urb->transfer_buffer, mdc800->in,8);
849 			mdc800->write_urb->dev = mdc800->dev;
850 			retval = usb_submit_urb (mdc800->write_urb, GFP_KERNEL);
851 			if (retval) {
852 				dev_err(&mdc800->dev->dev,
853 					"submitting write urb fails "
854 					"(retval=%i)\n", retval);
855 				mutex_unlock(&mdc800->io_lock);
856 				return -EIO;
857 			}
858 			wait_event_timeout(mdc800->write_wait, mdc800->written,
859 					msecs_to_jiffies(TO_WRITE_GET_READY));
860 			mdc800->written = 0;
861 			if (mdc800->state == WORKING)
862 			{
863 				usb_kill_urb(mdc800->write_urb);
864 				mutex_unlock(&mdc800->io_lock);
865 				return -EIO;
866 			}
867 
868 			switch ((unsigned char) mdc800->in[1])
869 			{
870 				case 0x05: /* Download Image */
871 				case 0x3e: /* Take shot in Fine Mode (WCam Mode) */
872 					if (mdc800->pic_len < 0)
873 					{
874 						dev_err(&mdc800->dev->dev,
875 							"call 0x07 before "
876 							"0x05,0x3e\n");
877 						mdc800->state=READY;
878 						mutex_unlock(&mdc800->io_lock);
879 						return -EIO;
880 					}
881 					mdc800->pic_len=-1;
882 					fallthrough;
883 
884 				case 0x09: /* Download Thumbnail */
885 					mdc800->download_left=answersize+64;
886 					mdc800->state=DOWNLOAD;
887 					mdc800_usb_waitForIRQ (0,TO_DOWNLOAD_GET_BUSY);
888 					break;
889 
890 
891 				default:
892 					if (answersize)
893 					{
894 
895 						if (mdc800_usb_waitForIRQ (1,TO_READ_FROM_IRQ))
896 						{
897 							dev_err(&mdc800->dev->dev, "requesting answer from irq fails\n");
898 							mutex_unlock(&mdc800->io_lock);
899 							return -EIO;
900 						}
901 
902 						/* Write dummy data, (this is ugly but part of the USB Protocol */
903 						/* if you use endpoint 1 as bulk and not as irq) */
904 						memcpy (mdc800->out, mdc800->camera_response,8);
905 
906 						/* This is the interpreted answer */
907 						memcpy (&mdc800->out[8], mdc800->camera_response,8);
908 
909 						mdc800->out_ptr=0;
910 						mdc800->out_count=16;
911 
912 						/* Cache the Imagesize, if command was getImageSize */
913 						if (mdc800->in [1] == (char) 0x07)
914 						{
915 							mdc800->pic_len=(int) 65536*(unsigned char) mdc800->camera_response[0]+256*(unsigned char) mdc800->camera_response[1]+(unsigned char) mdc800->camera_response[2];
916 
917 							dev_dbg(&mdc800->dev->dev, "cached imagesize = %i\n", mdc800->pic_len);
918 						}
919 
920 					}
921 					else
922 					{
923 						if (mdc800_usb_waitForIRQ (0,TO_DEFAULT_COMMAND))
924 						{
925 							dev_err(&mdc800->dev->dev, "Command Timeout.\n");
926 							mutex_unlock(&mdc800->io_lock);
927 							return -EIO;
928 						}
929 					}
930 					mdc800->state=READY;
931 					break;
932 			}
933 		}
934 		i++;
935 	}
936 	mutex_unlock(&mdc800->io_lock);
937 	return i;
938 }
939 
940 
941 /***************************************************************************
942 	Init and Cleanup this driver (Structs and types)
943 ****************************************************************************/
944 
945 /* File Operations of this drivers */
946 static const struct file_operations mdc800_device_ops =
947 {
948 	.owner =	THIS_MODULE,
949 	.read =		mdc800_device_read,
950 	.write =	mdc800_device_write,
951 	.open =		mdc800_device_open,
952 	.release =	mdc800_device_release,
953 	.llseek =	noop_llseek,
954 };
955 
956 
957 
958 static const struct usb_device_id mdc800_table[] = {
959 	{ USB_DEVICE(MDC800_VENDOR_ID, MDC800_PRODUCT_ID) },
960 	{ }						/* Terminating entry */
961 };
962 
963 MODULE_DEVICE_TABLE (usb, mdc800_table);
964 /*
965  * USB Driver Struct for this device
966  */
967 static struct usb_driver mdc800_usb_driver =
968 {
969 	.name =		"mdc800",
970 	.probe =	mdc800_usb_probe,
971 	.disconnect =	mdc800_usb_disconnect,
972 	.id_table =	mdc800_table
973 };
974 
975 
976 
977 /************************************************************************
978 	Init and Cleanup this driver (Main Functions)
979 *************************************************************************/
980 
981 static int __init usb_mdc800_init (void)
982 {
983 	int retval = -ENODEV;
984 	/* Allocate Memory */
985 	mdc800=kzalloc (sizeof (struct mdc800_data), GFP_KERNEL);
986 	if (!mdc800)
987 		goto cleanup_on_fail;
988 
989 	mdc800->dev = NULL;
990 	mdc800->state=NOT_CONNECTED;
991 	mutex_init (&mdc800->io_lock);
992 
993 	init_waitqueue_head (&mdc800->irq_wait);
994 	init_waitqueue_head (&mdc800->write_wait);
995 	init_waitqueue_head (&mdc800->download_wait);
996 
997 	mdc800->irq_woken = 0;
998 	mdc800->downloaded = 0;
999 	mdc800->written = 0;
1000 
1001 	mdc800->irq_urb_buffer=kmalloc (8, GFP_KERNEL);
1002 	if (!mdc800->irq_urb_buffer)
1003 		goto cleanup_on_fail;
1004 	mdc800->write_urb_buffer=kmalloc (8, GFP_KERNEL);
1005 	if (!mdc800->write_urb_buffer)
1006 		goto cleanup_on_fail;
1007 	mdc800->download_urb_buffer=kmalloc (64, GFP_KERNEL);
1008 	if (!mdc800->download_urb_buffer)
1009 		goto cleanup_on_fail;
1010 
1011 	mdc800->irq_urb=usb_alloc_urb (0, GFP_KERNEL);
1012 	if (!mdc800->irq_urb)
1013 		goto cleanup_on_fail;
1014 	mdc800->download_urb=usb_alloc_urb (0, GFP_KERNEL);
1015 	if (!mdc800->download_urb)
1016 		goto cleanup_on_fail;
1017 	mdc800->write_urb=usb_alloc_urb (0, GFP_KERNEL);
1018 	if (!mdc800->write_urb)
1019 		goto cleanup_on_fail;
1020 
1021 	/* Register the driver */
1022 	retval = usb_register(&mdc800_usb_driver);
1023 	if (retval)
1024 		goto cleanup_on_fail;
1025 
1026 	printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
1027 	       DRIVER_DESC "\n");
1028 
1029 	return 0;
1030 
1031 	/* Clean driver up, when something fails */
1032 
1033 cleanup_on_fail:
1034 
1035 	if (mdc800 != NULL)
1036 	{
1037 		printk(KERN_ERR "mdc800: can't alloc memory!\n");
1038 
1039 		kfree(mdc800->download_urb_buffer);
1040 		kfree(mdc800->write_urb_buffer);
1041 		kfree(mdc800->irq_urb_buffer);
1042 
1043 		usb_free_urb(mdc800->write_urb);
1044 		usb_free_urb(mdc800->download_urb);
1045 		usb_free_urb(mdc800->irq_urb);
1046 
1047 		kfree (mdc800);
1048 	}
1049 	mdc800 = NULL;
1050 	return retval;
1051 }
1052 
1053 
1054 static void __exit usb_mdc800_cleanup (void)
1055 {
1056 	usb_deregister (&mdc800_usb_driver);
1057 
1058 	usb_free_urb (mdc800->irq_urb);
1059 	usb_free_urb (mdc800->download_urb);
1060 	usb_free_urb (mdc800->write_urb);
1061 
1062 	kfree (mdc800->irq_urb_buffer);
1063 	kfree (mdc800->write_urb_buffer);
1064 	kfree (mdc800->download_urb_buffer);
1065 
1066 	kfree (mdc800);
1067 	mdc800 = NULL;
1068 }
1069 
1070 module_init (usb_mdc800_init);
1071 module_exit (usb_mdc800_cleanup);
1072 
1073 MODULE_AUTHOR( DRIVER_AUTHOR );
1074 MODULE_DESCRIPTION( DRIVER_DESC );
1075 MODULE_LICENSE("GPL");
1076 
1077