/*
 * copyright (C) 1999/2000 by Henning Zabel <henning@uni-paderborn.de>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */


/*
 *	USB-Kernel Driver for the Mustek MDC800 Digital Camera
 *	(c) 1999/2000 Henning Zabel <henning@uni-paderborn.de>
 *
 *
 * The driver brings the USB functions of the MDC800 to Linux.
 * To use the Camera you must support the USB Protocoll of the camera
 * to the Kernel Node.
 * The Driver uses a misc device Node. Create it with :
 * mknod /dev/mustek c 180 32
 *
 * The driver supports only one camera.
 * 
 * Fix: mdc800 used sleep_on and slept with io_lock held.
 * Converted sleep_on to waitqueues with schedule_timeout and made io_lock
 * a semaphore from a spinlock.
 * by Oliver Neukum <520047054719-0001@t-online.de>
 * (02/12/2001)
 * 
 * Identify version on module load.
 * (08/04/2001) gb
 *
 * version 0.7.5
 * Fixed potential SMP races with Spinlocks.
 * Thanks to Oliver Neukum <oliver.neukum@lrz.uni-muenchen.de> who 
 * noticed the race conditions.
 * (30/10/2000)
 *
 * Fixed: Setting urb->dev before submitting urb.
 * by Greg KH <greg@kroah.com>
 * (13/10/2000)
 *
 * version 0.7.3
 * bugfix : The mdc800->state field gets set to READY after the
 * the diconnect function sets it to NOT_CONNECTED. This makes the
 * driver running like the camera is connected and causes some
 * hang ups.
 *
 * version 0.7.1
 * MOD_INC and MOD_DEC are changed in usb_probe to prevent load/unload
 * problems when compiled as Module.
 * (04/04/2000)
 *
 * The mdc800 driver gets assigned the USB Minor 32-47. The Registration
 * was updated to use these values.
 * (26/03/2000)
 *
 * The Init und Exit Module Function are updated.
 * (01/03/2000)
 *
 * version 0.7.0
 * Rewrite of the driver : The driver now uses URB's. The old stuff
 * has been removed.
 *
 * version 0.6.0
 * Rewrite of this driver: The Emulation of the rs232 protocoll
 * has been removed from the driver. A special executeCommand function
 * for this driver is included to gphoto.
 * The driver supports two kind of communication to bulk endpoints.
 * Either with the dev->bus->ops->bulk... or with callback function.
 * (09/11/1999)
 *
 * version 0.5.0:
 * first Version that gets a version number. Most of the needed
 * functions work.
 * (20/10/1999)
 */

#include <linux/version.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/random.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/smp_lock.h>

#include <linux/usb.h>
#include <linux/fs.h>

/*
 * Version Information
 */
#define DRIVER_VERSION "v0.7.5 (30/10/2000)"
#define DRIVER_AUTHOR "Henning Zabel <henning@uni-paderborn.de>"
#define DRIVER_DESC "USB Driver for Mustek MDC800 Digital Camera"

/* Vendor and Product Information */
#define MDC800_VENDOR_ID 	0x055f
#define MDC800_PRODUCT_ID	0xa800

/* Timeouts (msec) */
#define TO_DOWNLOAD_GET_READY		1500
#define TO_DOWNLOAD_GET_BUSY		1500
#define TO_WRITE_GET_READY		1000
#define TO_DEFAULT_COMMAND		5000
#define TO_READ_FROM_IRQ 		TO_DEFAULT_COMMAND
#define TO_GET_READY			TO_DEFAULT_COMMAND

#ifdef CONFIG_USB_DYNAMIC_MINORS
#define MDC800_DEVICE_MINOR_BASE 0
#else
/* Minor Number of the device (create with mknod /dev/mustek c 180 32) */
#define MDC800_DEVICE_MINOR_BASE 32
#endif


/**************************************************************************
	Data and structs
***************************************************************************/


typedef enum {
	NOT_CONNECTED, READY, WORKING, DOWNLOAD
} mdc800_state;


/* Data for the driver */
struct mdc800_data
{
	struct usb_device *	dev;			// Device Data
	mdc800_state 		state;

	unsigned int		endpoint [4];

	struct urb *		irq_urb;
	wait_queue_head_t	irq_wait;
	int			irq_woken;
	char*			irq_urb_buffer;

	int			camera_busy;          // is camera busy ?
	int 			camera_request_ready; // Status to synchronize with irq
	char 			camera_response [8];  // last Bytes send after busy

	struct urb *   		write_urb;
	char*			write_urb_buffer;
	wait_queue_head_t	write_wait;
	int			written;


	struct urb *   		download_urb;
	char*			download_urb_buffer;
	wait_queue_head_t	download_wait;
	int			downloaded;
	int			download_left;		// Bytes left to download ?


	/* Device Data */
	char			out [64];	// Answer Buffer
	int 			out_ptr;	// Index to the first not readen byte
	int			out_count;	// Bytes in the buffer

	int			open;		// Camera device open ?
	struct semaphore	io_lock;	// IO -lock

	char 			in [8];		// Command Input Buffer
	int  			in_count;

	int			pic_index;	// Cache for the Imagesize (-1 for nothing cached )
	int			pic_len;
	int			minor;
};


/* Specification of the Endpoints */
static struct usb_endpoint_descriptor mdc800_ed [4] =
{
	{ 0,0, 0x01, 0x02,  8, 0,0,0 },
	{ 0,0, 0x82, 0x03,  8, 0,0,0 },
	{ 0,0, 0x03, 0x02, 64, 0,0,0 },
	{ 0,0, 0x84, 0x02, 64, 0,0,0 }
};


/* The Variable used by the driver */
static struct mdc800_data* mdc800=0;


/***************************************************************************
	The USB Part of the driver
****************************************************************************/

static int mdc800_endpoint_equals (struct usb_endpoint_descriptor *a,struct usb_endpoint_descriptor *b)
{
	return (
		   ( a->bEndpointAddress == b->bEndpointAddress )
		&& ( a->bmAttributes     == b->bmAttributes     )
		&& ( a->wMaxPacketSize   == b->wMaxPacketSize   )
	);
}


/*
 * Checks wether the camera responds busy
 */
static int mdc800_isBusy (char* ch)
{
	int i=0;
	while (i<8)
	{
		if (ch [i] != (char)0x99)
			return 0;
		i++;
	}
	return 1;
}


/*
 * Checks wether the Camera is ready
 */
static int mdc800_isReady (char *ch)
{
	int i=0;
	while (i<8)
	{
		if (ch [i] != (char)0xbb)
			return 0;
		i++;
	}
	return 1;
}



/*
 * USB IRQ Handler for InputLine
 */
static void mdc800_usb_irq (struct urb *urb)
{
	int data_received=0, wake_up;
	unsigned char* b=urb->transfer_buffer;
	struct mdc800_data* mdc800=urb->context;

	if (urb->status >= 0)
	{

		//dbg ("%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]);

		if (mdc800_isBusy (b))
		{
			if (!mdc800->camera_busy)
			{
				mdc800->camera_busy=1;
				dbg ("gets busy");
			}
		}
		else
		{
			if (mdc800->camera_busy && mdc800_isReady (b))
			{
				mdc800->camera_busy=0;
				dbg ("gets ready");
			}
		}
		if (!(mdc800_isBusy (b) || mdc800_isReady (b)))
		{
			/* Store Data in camera_answer field */
			dbg ("%i %i %i %i %i %i %i %i ",b[0],b[1],b[2],b[3],b[4],b[5],b[6],b[7]);

			memcpy (mdc800->camera_response,b,8);
			data_received=1;
		}
	}
	wake_up= ( mdc800->camera_request_ready > 0 )
		&&
		(
			((mdc800->camera_request_ready == 1) && (!mdc800->camera_busy))
		||
			((mdc800->camera_request_ready == 2) && data_received)
		||
			((mdc800->camera_request_ready == 3) && (mdc800->camera_busy))
		||
			(urb->status < 0)
		);

	if (wake_up)
	{
		mdc800->camera_request_ready=0;
		mdc800->irq_woken=1;
		wake_up_interruptible (&mdc800->irq_wait);
	}
}


/*
 * Waits a while until the irq responds that camera is ready
 *
 *  mode : 0: Wait for camera gets ready
 *         1: Wait for receiving data
 *         2: Wait for camera gets busy
 *
 * msec: Time to wait
 */
static int mdc800_usb_waitForIRQ (int mode, int msec)
{
        DECLARE_WAITQUEUE(wait, current);

	mdc800->camera_request_ready=1+mode;

	add_wait_queue(&mdc800->irq_wait, &wait);
	set_current_state(TASK_INTERRUPTIBLE);
	if (!mdc800->irq_woken)
	{
		schedule_timeout (msec*HZ/1000);
	}
        remove_wait_queue(&mdc800->irq_wait, &wait);
	set_current_state(TASK_RUNNING);
	mdc800->irq_woken = 0;

	if (mdc800->camera_request_ready>0)
	{
		mdc800->camera_request_ready=0;
		err ("timeout waiting for camera.");
		return -1;
	}
	
	if (mdc800->state == NOT_CONNECTED)
	{
		warn ("Camera gets disconnected during waiting for irq.");
		mdc800->camera_request_ready=0;
		return -2;
	}
	
	return 0;
}


/*
 * The write_urb callback function
 */
static void mdc800_usb_write_notify (struct urb *urb)
{
	struct mdc800_data* mdc800=urb->context;

	if (urb->status != 0)
	{
		err ("writing command fails (status=%i)", urb->status);
	}
	else
	{	
		mdc800->state=READY;
	}
	mdc800->written = 1;
	wake_up_interruptible (&mdc800->write_wait);
}


/*
 * The download_urb callback function
 */
static void mdc800_usb_download_notify (struct urb *urb)
{
	struct mdc800_data* mdc800=urb->context;

	if (urb->status == 0)
	{
		/* Fill output buffer with these data */
		memcpy (mdc800->out,  urb->transfer_buffer, 64);
		mdc800->out_count=64;
		mdc800->out_ptr=0;
		mdc800->download_left-=64;
		if (mdc800->download_left == 0)
		{
			mdc800->state=READY;
		}
	}
	else
	{
		err ("request bytes fails (status:%i)", urb->status);
	}
	mdc800->downloaded = 1;
	wake_up_interruptible (&mdc800->download_wait);
}


/***************************************************************************
	Probing for the Camera
 ***************************************************************************/

static struct usb_driver mdc800_usb_driver;

/*
 * Callback to search the Mustek MDC800 on the USB Bus
 */
static void* mdc800_usb_probe (struct usb_device *dev ,unsigned int ifnum,
			       const struct usb_device_id *id)
{
	int i,j;
	struct usb_interface_descriptor	*intf_desc;
	int irq_interval=0;
	int retval;

	dbg ("(mdc800_usb_probe) called.");


	if (mdc800->dev != 0)
	{
		warn ("only one Mustek MDC800 is supported.");
		return 0;
	}

	if (dev->descriptor.bNumConfigurations != 1)
	{
		err ("probe fails -> wrong Number of Configuration");
		return 0;
	}
	intf_desc=&dev->actconfig->interface[ifnum].altsetting[0];

	if (
			( intf_desc->bInterfaceClass != 0xff )
		||	( intf_desc->bInterfaceSubClass != 0 )
		|| ( intf_desc->bInterfaceProtocol != 0 )
		|| ( intf_desc->bNumEndpoints != 4)
	)
	{
		err ("probe fails -> wrong Interface");
		return 0;
	}

	/* Check the Endpoints */
	for (i=0; i<4; i++)
	{
		mdc800->endpoint[i]=-1;
		for (j=0; j<4; j++)
		{
			if (mdc800_endpoint_equals (&intf_desc->endpoint [j],&mdc800_ed [i]))
			{
				mdc800->endpoint[i]=intf_desc->endpoint [j].bEndpointAddress ;
				if (i==1)
				{
					irq_interval=intf_desc->endpoint [j].bInterval;
				}

				continue;
			}
		}
		if (mdc800->endpoint[i] == -1)
		{
			err ("probe fails -> Wrong Endpoints.");
			return 0;
		}
	}


	usb_driver_claim_interface (&mdc800_usb_driver, &dev->actconfig->interface[ifnum], mdc800);
	if (usb_set_interface (dev, ifnum, 0) < 0)
	{
		err ("MDC800 Configuration fails.");
		return 0;
	}

	info ("Found Mustek MDC800 on USB.");

	down (&mdc800->io_lock);

	retval = usb_register_dev (&mdc800_usb_driver, 1, &mdc800->minor);
	if (retval && (retval != -ENODEV)) {
		err ("Not able to get a minor for this device.");
		return 0;
	}

	mdc800->dev=dev;
	mdc800->open=0;

	/* Setup URB Structs */
	FILL_INT_URB (
		mdc800->irq_urb,
		mdc800->dev,
		usb_rcvintpipe (mdc800->dev,mdc800->endpoint [1]),
		mdc800->irq_urb_buffer,
		8,
		mdc800_usb_irq,
		mdc800,
		irq_interval
	);

	FILL_BULK_URB (
		mdc800->write_urb,
		mdc800->dev,
		usb_sndbulkpipe (mdc800->dev, mdc800->endpoint[0]),
		mdc800->write_urb_buffer,
		8,
		mdc800_usb_write_notify,
		mdc800
	);

	FILL_BULK_URB (
		mdc800->download_urb,
		mdc800->dev,
		usb_rcvbulkpipe (mdc800->dev, mdc800->endpoint [3]),
		mdc800->download_urb_buffer,
		64,
		mdc800_usb_download_notify,
		mdc800
	);

	mdc800->state=READY;

	up (&mdc800->io_lock);