/*
 * 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 */

/* 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 */
/* note that the capture command also controls the output dimensions */
/* 0x60 -> 160x120, 0x61 -> 320x240 0x62 -> 640x480 depends on camera */
/* 0x62 is not correct, at least for some cams. Should be 0x63 ? */

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

	u8 cam_type;

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

/* The driver only supports 320x240 so far. */
static struct v4l2_pix_format sq905_mode[1] = {
	{ 320, 240, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
		.bytesperline = 320,
		.sizeimage = 320 * 240,
		.colorspace = V4L2_COLORSPACE_SRGB,
		.priv = 0}
};

struct cam_type {
	u32 ident_word;
	char *name;
	struct v4l2_pix_format *min_mode;
	u8 num_modes;
	u8 sensor_flags;
};

#define SQ905_FLIP_HORIZ (1 << 0)
#define SQ905_FLIP_VERT  (1 << 1)

/* Last entry is default if nothing else matches */
static struct cam_type cam_types[] = {
	{ 0x19010509, "PocketCam", &sq905_mode[0], 1, SQ905_FLIP_HORIZ },
	{ 0x32010509, "Magpix", &sq905_mode[0], 1, SQ905_FLIP_HORIZ },
	{ 0, "Default", &sq905_mode[0], 1, SQ905_FLIP_HORIZ | SQ905_FLIP_VERT }
};

/*
 * 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 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;
	}

	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 = sq905_mode[0].sizeimage + FRAME_HEADER_LEN;
		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)
				gspca_frame_add(gspca_dev, packet_type,
						frame, data, data_len);
			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;

	cam->cam_mode = sq905_mode;
	cam->nmodes = 1;
	/* We don't use the buffer gspca allocates so make it small. */
	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)
{
	struct sd *dev = (struct sd *) 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. */
	ident = le32_to_cpup((u32 *)gspca_dev->usb_buf);
	ret = sq905_command(gspca_dev, SQ905_CLEAR);
	if (ret < 0)
		return ret;
	dev->cam_type = 0;
	while (dev->cam_type < ARRAY_SIZE(cam_types) - 1 &&
	       ident != cam_types[dev->cam_type].ident_word)
		dev->cam_type++;
	PDEBUG(D_CONF, "SQ905 camera %s, ID %08x detected",
	       cam_types[dev->cam_type].name, ident);
	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 */
	ret = sq905_command(&dev->gspca_dev, SQ905_CAPTURE_MED);
	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);