/*
 * SQ905 subdriver
 *
 * Copyright (C) 2008, 2009 Adam Baker and Theodore Kilgore
 *
 * 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
 * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

/*
 * History and Acknowledgments
 *
 * The original Linux driver for SQ905 based cameras was written by
 * Marcell Lengyel and furter developed by many other contributers
 * and is available from http://sourceforge.net/projects/sqcam/
 *
 * This driver takes advantage of the reverse engineering work done for
 * that driver and for libgphoto2 but shares no code with them.
 *
 * This driver has used as a base the finepix driver and other gspca
 * based drivers and may still contain code fragments taken from those
 * drivers.
 */

#define MODULE_NAME "sq905"

#include <linux/workqueue.h>
#include "gspca.h"

MODULE_AUTHOR("Adam Baker <linux@baker-net.org.uk>, "
                "Theodore Kilgore <kilgota@auburn.edu>");
MODULE_DESCRIPTION("GSPCA/SQ905 USB Camera Driver");
MODULE_LICENSE("GPL");

/* Default timeouts, in ms */
#define SQ905_CMD_TIMEOUT 500
#define SQ905_DATA_TIMEOUT 1000

/* Maximum transfer size to use. */
#define SQ905_MAX_TRANSFER 0x8000
#define FRAME_HEADER_LEN 64

/* The known modes, or registers. These go in the "value" slot. */

/* 00 is "none" obviously */

#define SQ905_BULK_READ 0x03    /* precedes any bulk read */
#define SQ905_COMMAND   0x06    /* precedes the command codes below */
#define SQ905_PING      0x07    /* when reading an "idling" command */
#define SQ905_READ_DONE 0xc0    /* ack bulk read completed */

/* Any non-zero value in the bottom 2 bits of the 2nd byte of
 * the ID appears to indicate the camera can do 640*480. If the
 * LSB of that byte is set the image is just upside down, otherwise
 * it is rotated 180 degrees. */
#define SQ905_HIRES_MASK        0x00000300
#define SQ905_ORIENTATION_MASK  0x00000100

/* Some command codes. These go in the "index" slot. */

#define SQ905_ID      0xf0      /* asks for model string */
#define SQ905_CONFIG  0x20      /* gets photo alloc. table, not used here */
#define SQ905_DATA    0x30      /* accesses photo data, not used here */
#define SQ905_CLEAR   0xa0      /* clear everything */
#define SQ905_CAPTURE_LOW  0x60 /* Starts capture at 160x120 */
#define SQ905_CAPTURE_MED  0x61 /* Starts capture at 320x240 */
#define SQ905_CAPTURE_HIGH 0x62 /* Starts capture at 640x480 (some cams only) */
/* note that the capture command also controls the output dimensions */

/* Structure to hold all of our device specific stuff */
struct sd {
        struct gspca_dev gspca_dev;     /* !! must be the first item */

        /*
         * Driver stuff
         */
        struct work_struct work_struct;
        struct workqueue_struct *work_thread;
};

static struct v4l2_pix_format sq905_mode[] = {
        { 160, 120, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
                .bytesperline = 160,
                .sizeimage = 160 * 120,
                .colorspace = V4L2_COLORSPACE_SRGB,
                .priv = 0},
        { 320, 240, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
                .bytesperline = 320,
                .sizeimage = 320 * 240,
                .colorspace = V4L2_COLORSPACE_SRGB,
                .priv = 0},
        { 640, 480, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
                .bytesperline = 640,
                .sizeimage = 640 * 480,
                .colorspace = V4L2_COLORSPACE_SRGB,
                .priv = 0}
};

/*
 * Send a command to the camera.
 */
static int sq905_command(struct gspca_dev *gspca_dev, u16 index)
{
        int ret;

        gspca_dev->usb_buf[0] = '\0';
        ret = usb_control_msg(gspca_dev->dev,
                              usb_sndctrlpipe(gspca_dev->dev, 0),
                              USB_REQ_SYNCH_FRAME,                /* request */
                              USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
                              SQ905_COMMAND, index, gspca_dev->usb_buf, 1,
                              SQ905_CMD_TIMEOUT);
        if (ret < 0) {
                PDEBUG(D_ERR, "%s: usb_control_msg failed (%d)",
                        __func__, ret);
                return ret;
        }

        ret = usb_control_msg(gspca_dev->dev,
                              usb_sndctrlpipe(gspca_dev->dev, 0),
                              USB_REQ_SYNCH_FRAME,                /* request */
                              USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
                              SQ905_PING, 0, gspca_dev->usb_buf, 1,
                              SQ905_CMD_TIMEOUT);
        if (ret < 0) {
                PDEBUG(D_ERR, "%s: usb_control_msg failed 2 (%d)",
                        __func__, ret);
                return ret;
        }

        return 0;
}

/*
 * Acknowledge the end of a frame - see warning on sq905_command.
 */
static int sq905_ack_frame(struct gspca_dev *gspca_dev)
{
        int ret;

        gspca_dev->usb_buf[0] = '\0';
        ret = usb_control_msg(gspca_dev->dev,
                              usb_sndctrlpipe(gspca_dev->dev, 0),
                              USB_REQ_SYNCH_FRAME,                /* request */
                              USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
                              SQ905_READ_DONE, 0, gspca_dev->usb_buf, 1,
                              SQ905_CMD_TIMEOUT);
        if (ret < 0) {
                PDEBUG(D_ERR, "%s: usb_control_msg failed (%d)", __func__, ret);
                return ret;
        }

        return 0;
}

/*
 *  request and read a block of data - see warning on sq905_command.
 */
static int
sq905_read_data(struct gspca_dev *gspca_dev, u8 *data, int size)
{
        int ret;
        int act_len;

        gspca_dev->usb_buf[0] = '\0';
        ret = usb_control_msg(gspca_dev->dev,
                              usb_sndctrlpipe(gspca_dev->dev, 0),
                              USB_REQ_SYNCH_FRAME,                /* request */
                              USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
                              SQ905_BULK_READ, size, gspca_dev->usb_buf,
                              1, SQ905_CMD_TIMEOUT);
        if (ret < 0) {
                PDEBUG(D_ERR, "%s: usb_control_msg failed (%d)", __func__, ret);
                return ret;
        }
        ret = usb_bulk_msg(gspca_dev->dev,
                           usb_rcvbulkpipe(gspca_dev->dev, 0x81),
                           data, size, &act_len, SQ905_DATA_TIMEOUT);

        /* successful, it returns 0, otherwise  negative */
        if (ret < 0 || act_len != size) {
                PDEBUG(D_ERR, "bulk read fail (%d) len %d/%d",
                        ret, act_len, size);
                return -EIO;
        }
        return 0;
}

/* This function is called as a workqueue function and runs whenever the camera
 * is streaming data. Because it is a workqueue function it is allowed to sleep
 * so we can use synchronous USB calls. To avoid possible collisions with other
 * threads attempting to use the camera's USB interface we take the gspca
 * usb_lock when performing USB operations. In practice the only thing we need
 * to protect against is the usb_set_interface call that gspca makes during
 * stream_off as the camera doesn't provide any controls that the user could try
 * to change.
 */
static void sq905_dostream(struct work_struct *work)
{
        struct sd *dev = container_of(work, struct sd, work_struct);
        struct gspca_dev *gspca_dev = &dev->gspca_dev;
        struct gspca_frame *frame;
        int bytes_left; /* bytes remaining in current frame. */
        int data_len;   /* size to use for the next read. */
        int header_read; /* true if we have already read the frame header. */
        int discarding; /* true if we failed to get space for frame. */
        int packet_type;
        int frame_sz;
        int ret;
        u8 *data;
        u8 *buffer;

        buffer = kmalloc(SQ905_MAX_TRANSFER, GFP_KERNEL | GFP_DMA);
        mutex_lock(&gspca_dev->usb_lock);
        if (!buffer) {
                PDEBUG(D_ERR, "Couldn't allocate USB buffer");
                goto quit_stream;
        }

        frame_sz = gspca_dev->cam.cam_mode[gspca_dev->curr_mode].sizeimage
                        + FRAME_HEADER_LEN;

        while (gspca_dev->present && gspca_dev->streaming) {
                /* Need a short delay to ensure streaming flag was set by
                 * gspca and to make sure gspca can grab the mutex. */
                mutex_unlock(&gspca_dev->usb_lock);
                msleep(1);

                /* request some data and then read it until we have
                 * a complete frame. */
                bytes_left = frame_sz;
                header_read = 0;
                discarding = 0;

                while (bytes_left > 0) {
                        data_len = bytes_left > SQ905_MAX_TRANSFER ?
                                SQ905_MAX_TRANSFER : bytes_left;
                        mutex_lock(&gspca_dev->usb_lock);
                        if (!gspca_dev->present)
                                goto quit_stream;
                        ret = sq905_read_data(gspca_dev, buffer, data_len);
                        if (ret < 0)
                                goto quit_stream;
                        mutex_unlock(&gspca_dev->usb_lock);
                        PDEBUG(D_STREAM,
                                "Got %d bytes out of %d for frame",
                                data_len, bytes_left);
                        bytes_left -= data_len;
                        data = buffer;
                        if (!header_read) {
                                packet_type = FIRST_PACKET;
                                /* The first 64 bytes of each frame are
                                 * a header full of FF 00 bytes */
                                data += FRAME_HEADER_LEN;
                                data_len -= FRAME_HEADER_LEN;
                                header_read = 1;
                        } else if (bytes_left == 0) {
                                packet_type = LAST_PACKET;
                        } else {
                                packet_type = INTER_PACKET;
                        }
                        frame = gspca_get_i_frame(gspca_dev);
                        if (frame && !discarding) {
                                frame = gspca_frame_add(gspca_dev, packet_type,
                                                frame, data, data_len);
                                /* If entire frame fits in one packet we still
                                   need to add a LAST_PACKET */
                                if (packet_type == FIRST_PACKET &&
                                    bytes_left == 0)
                                        frame = gspca_frame_add(gspca_dev,
                                                        LAST_PACKET,
                                                        frame, data, 0);
                        } else {
                                discarding = 1;
                        }
                }
                /* acknowledge the frame */
                mutex_lock(&gspca_dev->usb_lock);
                if (!gspca_dev->present)
                        goto quit_stream;
                ret = sq905_ack_frame(gspca_dev);
                if (ret < 0)
                        goto quit_stream;
        }
quit_stream:
        /* the usb_lock is already acquired */
        if (gspca_dev->present)
                sq905_command(gspca_dev, SQ905_CLEAR);
        mutex_unlock(&gspca_dev->usb_lock);
        kfree(buffer);
}

/* This function is called at probe time just before sd_init */
static int sd_config(struct gspca_dev *gspca_dev,
                const struct usb_device_id *id)
{
        struct cam *cam = &gspca_dev->cam;
        struct sd *dev = (struct sd *) gspca_dev;

        /* We don't use the buffer gspca allocates so make it small. */
        cam->bulk = 1;
        cam->bulk_size = 64;

        INIT_WORK(&dev->work_struct, sq905_dostream);

        return 0;
}

/* called on streamoff with alt==0 and on disconnect */
/* the usb_lock is held at entry - restore on exit */
static void sd_stop0(struct gspca_dev *gspca_dev)
{
        struct sd *dev = (struct sd *) gspca_dev;

        /* wait for the work queue to terminate */
        mutex_unlock(&gspca_dev->usb_lock);
        /* This waits for sq905_dostream to finish */
        destroy_workqueue(dev->work_thread);
        dev->work_thread = NULL;
        mutex_lock(&gspca_dev->usb_lock);
}

/* this function is called at probe and resume time */
static int sd_init(struct gspca_dev *gspca_dev)
{
        u32 ident;
        int ret;

        /* connect to the camera and read
         * the model ID and process that and put it away.
         */
        ret = sq905_command(gspca_dev, SQ905_CLEAR);
        if (ret < 0)
                return ret;
        ret = sq905_command(gspca_dev, SQ905_ID);
        if (ret < 0)
                return ret;
        ret = sq905_read_data(gspca_dev, gspca_dev->usb_buf, 4);
        if (ret < 0)
                return ret;
        /* usb_buf is allocated with kmalloc so is aligned.
         * Camera model number is the right way round if we assume this
         * reverse engineered ID is supposed to be big endian. */
        ident = be32_to_cpup((__be32 *)gspca_dev->usb_buf);
        ret = sq905_command(gspca_dev, SQ905_CLEAR);
        if (ret < 0)
                return ret;
        PDEBUG(D_CONF, "SQ905 camera ID %08x detected", ident);
        gspca_dev->cam.cam_mode = sq905_mode;
        gspca_dev->cam.nmodes = ARRAY_SIZE(sq905_mode);
        if (!(ident & SQ905_HIRES_MASK))
                gspca_dev->cam.nmodes--;

        if (ident & SQ905_ORIENTATION_MASK)
                gspca_dev->cam.input_flags = V4L2_IN_ST_VFLIP;
        else
                gspca_dev->cam.input_flags = V4L2_IN_ST_VFLIP |
                                             V4L2_IN_ST_HFLIP;
        return 0;
}

/* Set up for getting frames. */
static int sd_start(struct gspca_dev *gspca_dev)
{
        struct sd *dev = (struct sd *) gspca_dev;
        int ret;

        /* "Open the shutter" and set size, to start capture */
        switch (gspca_dev->curr_mode) {
        default:
/*      case 2: */
                PDEBUG(D_STREAM, "Start streaming at high resolution");
                ret = sq905_command(&dev->gspca_dev, SQ905_CAPTURE_HIGH);
                break;
        case 1:
                PDEBUG(D_STREAM, "Start streaming at medium resolution");
                ret = sq905_command(&dev->gspca_dev, SQ905_CAPTURE_MED);
                break;
        case 0:
                PDEBUG(D_STREAM, "Start streaming at low resolution");
                ret = sq905_command(&dev->gspca_dev, SQ905_CAPTURE_LOW);
        }

        if (ret < 0) {
                PDEBUG(D_ERR, "Start streaming command failed");
                return ret;
        }
        /* Start the workqueue function to do the streaming */
        dev->work_thread = create_singlethread_workqueue(MODULE_NAME);
        queue_work(dev->work_thread, &dev->work_struct);

        return 0;
}

/* Table of supported USB devices */
static const __devinitdata struct usb_device_id device_table[] = {
        {USB_DEVICE(0x2770, 0x9120)},
        {}
};

MODULE_DEVICE_TABLE(usb, device_table);

/* sub-driver description */
static const struct sd_desc sd_desc = {
        .name   = MODULE_NAME,
        .config = sd_config,
        .init   = sd_init,
        .start  = sd_start,
        .stop0  = sd_stop0,
};

/* -- device connect -- */
static int sd_probe(struct usb_interface *intf,
                const struct usb_device_id *id)
{
        return gspca_dev_probe(intf, id,
                        &sd_desc,
                        sizeof(struct sd),
                        THIS_MODULE);
}

static struct usb_driver sd_driver = {
        .name       = MODULE_NAME,
        .id_table   = device_table,
        .probe      = sd_probe,
        .disconnect = gspca_disconnect,
#ifdef CONFIG_PM
        .suspend = gspca_suspend,
        .resume  = gspca_resume,
#endif
};

/* -- module insert / remove -- */
static int __init sd_mod_init(void)
{
        int ret;

        ret = usb_register(&sd_driver);
        if (ret < 0)
                return ret;
        PDEBUG(D_PROBE, "registered");
        return 0;
}

static void __exit sd_mod_exit(void)
{
        usb_deregister(&sd_driver);
        PDEBUG(D_PROBE, "deregistered");
}

module_init(sd_mod_init);
module_exit(sd_mod_exit);