/*
 * Copyright (C) 1999-2000 by David Brownell <dbrownell@users.sourceforge.net>
 *
 * 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 driver for Kodak DC-2XX series digital still cameras
 *
 * The protocol here is the same as the one going over a serial line, but
 * it uses USB for speed.  Set up /dev/kodak, get gphoto (www.gphoto.org),
 * and have fun!
 *
 * This should also work for a number of other digital (non-Kodak) cameras,
 * by adding the vendor and product IDs to the table below.  They'll need
 * to be the sort using USB just as a fast bulk data channel.
 */

/*
 * HISTORY
 *
 * 26 August, 1999 -- first release (0.1), works with my DC-240.
 *      The DC-280 (2Mpixel) should also work, but isn't tested.
 *      If you use gphoto, make sure you have the USB updates.
 *      Lives in a 2.3.14 or so Linux kernel, in drivers/usb.
 * 31 August, 1999 -- minor update to recognize DC-260 and handle
 *      its endpoints being in a different order.  Note that as
 *      of gPhoto 0.36pre, the USB updates are integrated.
 * 12 Oct, 1999 -- handle DC-280 interface class (0xff not 0x0);
 *      added timeouts to bulk_msg calls.  Minor updates, docs.
 * 03 Nov, 1999 -- update for 2.3.25 kernel API changes.
 * 08 Jan, 2000 .. multiple camera support
 * 12 Aug, 2000 .. add some real locking, remove an Oops
 * 10 Oct, 2000 .. usb_device_id table created. 
 * 01 Nov, 2000 .. usb_device_id support added by Adam J. Richter
 * 08 Apr, 2001 .. Identify version on module load. gb
 *
 * Thanks to:  the folk who've provided USB product IDs, sent in
 * patches, and shared their successes!
 */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/random.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/devfs_fs_kernel.h>

#ifdef CONFIG_USB_DEBUG
        #define DEBUG
#else
        #undef DEBUG
#endif
#include <linux/usb.h>


/* /dev/usb dir. */
extern devfs_handle_t usb_devfs_handle;                 

/*
 * Version Information
 */
#define DRIVER_VERSION "v1.0.0"
#define DRIVER_AUTHOR "David Brownell, <dbrownell@users.sourceforge.net>"
#define DRIVER_DESC "USB Camera Driver for Kodak DC-2xx series cameras"


/* current USB framework handles max of 16 USB devices per driver */
#define MAX_CAMERAS             16

/* USB char devs use USB_MAJOR and from USB_CAMERA_MINOR_BASE up */
#define USB_CAMERA_MINOR_BASE   80


// XXX remove packet size limit, now that bulk transfers seem fixed

/* Application protocol limit is 0x8002; USB has disliked that limit! */
#define MAX_PACKET_SIZE         0x2000          /* e.g. image downloading */

#define MAX_READ_RETRY          5               /* times to retry reads */
#define MAX_WRITE_RETRY         5               /* times to retry writes */
#define RETRY_TIMEOUT           (HZ)            /* sleep between retries */


/* table of cameras that work through this driver */
static struct usb_device_id camera_table [] = {
        /* These have the same application level protocol */  
        { USB_DEVICE(0x040a, 0x0120) },         // Kodak DC-240
        { USB_DEVICE(0x040a, 0x0130) },         // Kodak DC-280
        { USB_DEVICE(0x040a, 0x0131) },         // Kodak DC-5000
        { USB_DEVICE(0x040a, 0x0132) },         // Kodak DC-3400

        /* These have a different application level protocol which
         * is part of the Flashpoint "DigitaOS".  That supports some
         * non-camera devices, and some non-Kodak cameras.
         * Use this driver to get USB and "OpenDis" to talk.
         */  
        { USB_DEVICE(0x040a, 0x0100) },         // Kodak DC-220
        { USB_DEVICE(0x040a, 0x0110) },         // Kodak DC-260
        { USB_DEVICE(0x040a, 0x0111) },         // Kodak DC-265
        { USB_DEVICE(0x040a, 0x0112) },         // Kodak DC-290
        { USB_DEVICE(0xf003, 0x6002) },         // HP PhotoSmart C500
        { USB_DEVICE(0x03f0, 0x4102) },         // HP PhotoSmart C618
        { USB_DEVICE(0x0a17, 0x1001) },         // Pentax EI-200

        /* Other USB devices may well work here too, so long as they
         * just stick to half duplex bulk packet exchanges.  That
         * means, among other things, no iso or interrupt endpoints.
         */

        { }                                     /* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, camera_table);


struct camera_state {
        struct usb_device       *dev;           /* USB device handle */
        int                     inEP;           /* read endpoint */
        int                     outEP;          /* write endpoint */
        const struct usb_device_id      *info;  /* DC-240, etc */
        int                     subminor;       /* which minor dev #? */
        struct semaphore        sem;            /* locks this struct */

        /* this is non-null iff the device is open */
        char                    *buf;           /* buffer for I/O */

        devfs_handle_t          devfs;          /* devfs device */

        /* always valid */
        wait_queue_head_t       wait;           /* for timed waits */
};

/* Support multiple cameras, possibly of different types.  */
static struct camera_state *minor_data [MAX_CAMERAS];

/* make this an rwlock if contention becomes an issue */
static DECLARE_MUTEX (state_table_mutex);

static ssize_t camera_read (struct file *file,
        char *buf, size_t len, loff_t *ppos)
{
        struct camera_state     *camera;
        int                     retries;
        int                     retval = 0;

        if (len > MAX_PACKET_SIZE)
                return -EINVAL;

        camera = (struct camera_state *) file->private_data;
        down (&camera->sem);
        if (!camera->dev) {
                up (&camera->sem);
                return -ENODEV;
        }

        /* Big reads are common, for image downloading.  Smaller ones
         * are also common (even "directory listing" commands don't
         * send very much data).  We preserve packet boundaries here,
         * they matter in the application protocol.
         */
        for (retries = 0; retries < MAX_READ_RETRY; retries++) {
                int                     count;

                if (signal_pending (current)) {
                        retval = -EINTR;
                        break;
                }

                retval = usb_bulk_msg (camera->dev,
                          usb_rcvbulkpipe (camera->dev, camera->inEP),
                          camera->buf, len, &count, HZ*10);

                dbg ("read (%Zd) - 0x%x %d", len, retval, count);

                if (!retval) {
                        if (copy_to_user (buf, camera->buf, count))
                                retval = -EFAULT;
                        else
                                retval = count;
                        break;
                }
                if (retval != USB_ST_TIMEOUT)
                        break;
                interruptible_sleep_on_timeout (&camera->wait, RETRY_TIMEOUT);

                dbg ("read (%Zd) - retry", len);
        }
        up (&camera->sem);
        return retval;
}

static ssize_t camera_write (struct file *file,
        const char *buf, size_t len, loff_t *ppos)
{
        struct camera_state     *camera;
        ssize_t                 bytes_written = 0;

        if (len > MAX_PACKET_SIZE)
                return -EINVAL;

        camera = (struct camera_state *) file->private_data;
        down (&camera->sem);
        if (!camera->dev) {
                up (&camera->sem);
                return -ENODEV;
        }
        
        /* most writes will be small: simple commands, sometimes with
         * parameters.  putting images (like borders) into the camera
         * would be the main use of big writes.
         */
        while (len > 0) {
                char            *obuf = camera->buf;
                int             maxretry = MAX_WRITE_RETRY;
                unsigned long   copy_size, thistime;

                /* it's not clear that retrying can do any good ... or that
                 * fragmenting application packets into N writes is correct.
                 */
                thistime = copy_size = len;
                if (copy_from_user (obuf, buf, copy_size)) {
                        bytes_written = -EFAULT;
                        break;
                }
                while (thistime) {
                        int             result;
                        int             count;

                        if (signal_pending (current)) {
                                if (!bytes_written)
                                        bytes_written = -EINTR;
                                goto done;
                        }

                        result = usb_bulk_msg (camera->dev,
                                 usb_sndbulkpipe (camera->dev, camera->outEP),
                                 obuf, thistime, &count, HZ*10);

                        if (result)
                                dbg ("write USB err - %d", result);

                        if (count) {
                                obuf += count;
                                thistime -= count;
                                maxretry = MAX_WRITE_RETRY;
                                continue;
                        } else if (!result)
                                break;
                                
                        if (result == USB_ST_TIMEOUT) { /* NAK - delay a bit */
                                if (!maxretry--) {
                                        if (!bytes_written)
                                                bytes_written = -ETIME;
                                        goto done;
                                }
                                interruptible_sleep_on_timeout (&camera->wait,
                                        RETRY_TIMEOUT);
                                continue;
                        } 
                        if (!bytes_written)
                                bytes_written = -EIO;
                        goto done;
                }
                bytes_written += copy_size;
                len -= copy_size;
                buf += copy_size;
        }
done:
        up (&camera->sem);
        dbg ("wrote %Zd", bytes_written); 
        return bytes_written;
}

static int camera_open (struct inode *inode, struct file *file)
{
        struct camera_state     *camera = NULL;
        int                     subminor;
        int                     value = 0;

        down (&state_table_mutex);
        subminor = MINOR (inode->i_rdev) - USB_CAMERA_MINOR_BASE;
        if (subminor < 0 || subminor >= MAX_CAMERAS
                        || !(camera = minor_data [subminor])) {
                up (&state_table_mutex);
                return -ENODEV;
        }
        down (&camera->sem);
        up (&state_table_mutex);

        if (camera->buf) {
                value = -EBUSY;
                goto done;
        }

        if (!(camera->buf = (char *) kmalloc (MAX_PACKET_SIZE, GFP_KERNEL))) {
                value = -ENOMEM;
                goto done;
        }

        dbg ("open #%d", subminor); 

        file->private_data = camera;
done:
        up (&camera->sem);
        return value;
}

static int camera_release (struct inode *inode, struct file *file)
{
        struct camera_state     *camera;
        int                     subminor;

        camera = (struct camera_state *) file->private_data;
        down (&state_table_mutex);
        down (&camera->sem);

        if (camera->buf) {
                kfree (camera->buf);
                camera->buf = 0;
        }
        subminor = camera->subminor;

        /* If camera was unplugged with open file ... */
        if (!camera->dev) {
                minor_data [subminor] = NULL;
                kfree (camera);
        } else
                up (&camera->sem);
        
        up (&state_table_mutex);

        dbg ("close #%d", subminor); 

        return 0;
}

        /* XXX should define some ioctls to expose camera type
         * to applications ... what USB exposes should suffice.
         * apps should be able to see the camera type.
         */
static /* const */ struct file_operations usb_camera_fops = {
            /* Uses GCC initializer extension; simpler to maintain */
        owner:          THIS_MODULE,
        read:           camera_read,
        write:          camera_write,
        open:           camera_open,
        release:        camera_release,
};



static void *
camera_probe (struct usb_device *dev, unsigned int ifnum, const struct usb_device_id *camera_info)
{
        int                             i;
        struct usb_interface_descriptor *interface;
        struct usb_endpoint_descriptor  *endpoint;
        int                             direction, ep;
        char name[8];
        struct camera_state             *camera = NULL;


        /* these have one config, one interface */
        if (dev->descriptor.bNumConfigurations != 1
                        || dev->config[0].bNumInterfaces != 1) {
                dbg ("Bogus camera config info");
                return NULL;
        }

        /* models differ in how they report themselves */
        interface = &dev->actconfig->interface[ifnum].altsetting[0];
        if ((interface->bInterfaceClass != USB_CLASS_PER_INTERFACE
                && interface->bInterfaceClass != USB_CLASS_VENDOR_SPEC)
                        || interface->bInterfaceSubClass != 0
                        || interface->bInterfaceProtocol != 0
                        || interface->bNumEndpoints != 2
                        ) {
                dbg ("Bogus camera interface info");
                return NULL;
        }


        /* select "subminor" number (part of a minor number) */
        down (&state_table_mutex);
        for (i = 0; i < MAX_CAMERAS; i++) {
                if (!minor_data [i])
                        break;
        }
        if (i >= MAX_CAMERAS) {
                info ("Ignoring additional USB Camera");
                goto bye;
        }

        /* allocate & init camera state */
        camera = minor_data [i] = kmalloc (sizeof *camera, GFP_KERNEL);
        if (!camera) {
                err ("no memory!");
                goto bye;
        }

        init_MUTEX (&camera->sem);
        camera->info = camera_info;
        camera->subminor = i;
        camera->buf = NULL;
        init_waitqueue_head (&camera->wait);


        /* get input and output endpoints (either order) */
        endpoint = interface->endpoint;
        camera->outEP = camera->inEP =  -1;

        ep = endpoint [0].bEndpointAddress & USB_ENDPOINT_NUMBER_MASK;
        direction = endpoint [0].bEndpointAddress & USB_ENDPOINT_DIR_MASK;
        if (direction == USB_DIR_IN)
                camera->inEP = ep;
        else
                camera->outEP = ep;

        ep = endpoint [1].bEndpointAddress & USB_ENDPOINT_NUMBER_MASK;
        direction = endpoint [1].bEndpointAddress & USB_ENDPOINT_DIR_MASK;
        if (direction == USB_DIR_IN)
                camera->inEP = ep;
        else
                camera->outEP = ep;

        if (camera->outEP == -1 || camera->inEP == -1
                        || endpoint [0].bmAttributes != USB_ENDPOINT_XFER_BULK
                        || endpoint [1].bmAttributes != USB_ENDPOINT_XFER_BULK
                        ) {
                dbg ("Bogus endpoints");
                goto error;
        }

        info ("USB Camera #%d connected, major/minor %d/%d", camera->subminor,
                USB_MAJOR, USB_CAMERA_MINOR_BASE + camera->subminor);

        camera->dev = dev;
        usb_inc_dev_use (dev);

        /* If we have devfs, register the device */
        sprintf(name, "dc2xx%d", camera->subminor);
        camera->devfs = devfs_register(usb_devfs_handle, name,
                                       DEVFS_FL_DEFAULT, USB_MAJOR,
                                       USB_CAMERA_MINOR_BASE + camera->subminor,
                                       S_IFCHR | S_IRUSR | S_IWUSR | S_IRGRP |
                                       S_IWGRP, &usb_camera_fops, NULL);

        goto bye;

error:
        minor_data [camera->subminor] = NULL;
        kfree (camera);
        camera = NULL;
bye:
        up (&state_table_mutex);
        return camera;
}

static void camera_disconnect(struct usb_device *dev, void *ptr)
{
        struct camera_state     *camera = (struct camera_state *) ptr;
        int                     subminor = camera->subminor;

        down (&state_table_mutex);
        down (&camera->sem);

        devfs_unregister(camera->devfs); 

        /* If camera's not opened, we can clean up right away.
         * Else apps see a disconnect on next I/O; the release cleans.
         */
        if (!camera->buf) {
                minor_data [subminor] = NULL;
                kfree (camera);
                camera = NULL;
        } else
                camera->dev = NULL;

        info ("USB Camera #%d disconnected", subminor);
        usb_dec_dev_use (dev);

        if (camera != NULL)
                up (&camera->sem);
        up (&state_table_mutex);
}

static /* const */ struct usb_driver camera_driver = {
        name:           "dc2xx",

        id_table:       camera_table,
        probe:          camera_probe,
        disconnect:     camera_disconnect,

        fops:           &usb_camera_fops,
        minor:          USB_CAMERA_MINOR_BASE
};


int __init usb_dc2xx_init(void)
{
        if (usb_register (&camera_driver) < 0)
                return -1;
        info(DRIVER_VERSION ":" DRIVER_DESC);
        return 0;
}

void __exit usb_dc2xx_cleanup(void)
{
        usb_deregister (&camera_driver);
}

module_init (usb_dc2xx_init);
module_exit (usb_dc2xx_cleanup);

MODULE_AUTHOR( DRIVER_AUTHOR );
MODULE_DESCRIPTION( DRIVER_DESC );
MODULE_LICENSE("GPL");