/*
 * Jeilinj subdriver
 *
 * Supports some Jeilin dual-mode cameras which use bulk transport and
 * download raw JPEG data.
 *
 * Copyright (C) 2009 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
 */

#define MODULE_NAME "jeilinj"

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

MODULE_AUTHOR("Theodore Kilgore <kilgota@auburn.edu>");
MODULE_DESCRIPTION("GSPCA/JEILINJ USB Camera Driver");
MODULE_LICENSE("GPL");

/* Default timeouts, in ms */
#define JEILINJ_CMD_TIMEOUT 500
#define JEILINJ_DATA_TIMEOUT 1000

/* Maximum transfer size to use. */
#define JEILINJ_MAX_TRANSFER 0x200

#define FRAME_HEADER_LEN 0x10

/* Structure to hold all of our device specific stuff */
struct sd {
	struct gspca_dev gspca_dev;	/* !! must be the first item */
	const struct v4l2_pix_format *cap_mode;
	/* Driver stuff */
	struct work_struct work_struct;
	struct workqueue_struct *work_thread;
	u8 quality;				 /* image quality */
	u8 jpegqual;				/* webcam quality */
	u8 jpeg_hdr[JPEG_HDR_SZ];
};

	struct jlj_command {
		unsigned char instruction[2];
		unsigned char ack_wanted;
	};

/* AFAICT these cameras will only do 320x240. */
static struct v4l2_pix_format jlj_mode[] = {
	{ 320, 240, V4L2_PIX_FMT_JPEG, V4L2_FIELD_NONE,
		.bytesperline = 320,
		.sizeimage = 320 * 240,
		.colorspace = V4L2_COLORSPACE_JPEG,
		.priv = 0}
};

/*
 * cam uses endpoint 0x03 to send commands, 0x84 for read commands,
 * and 0x82 for bulk transfer.
 */

/* All commands are two bytes only */
static int jlj_write2(struct gspca_dev *gspca_dev, unsigned char *command)
{
	int retval;

	memcpy(gspca_dev->usb_buf, command, 2);
	retval = usb_bulk_msg(gspca_dev->dev,
			usb_sndbulkpipe(gspca_dev->dev, 3),
			gspca_dev->usb_buf, 2, NULL, 500);
	if (retval < 0)
		err("command write [%02x] error %d",
				gspca_dev->usb_buf[0], retval);
	return retval;
}

/* Responses are one byte only */
static int jlj_read1(struct gspca_dev *gspca_dev, unsigned char response)
{
	int retval;

	retval = usb_bulk_msg(gspca_dev->dev,
	usb_rcvbulkpipe(gspca_dev->dev, 0x84),
				gspca_dev->usb_buf, 1, NULL, 500);
	response = gspca_dev->usb_buf[0];
	if (retval < 0)
		err("read command [%02x] error %d",
				gspca_dev->usb_buf[0], retval);
	return retval;
}

static int jlj_start(struct gspca_dev *gspca_dev)
{
	int i;
	int retval = -1;
	u8 response = 0xff;
	struct jlj_command start_commands[] = {
		{{0x71, 0x81}, 0},
		{{0x70, 0x05}, 0},
		{{0x95, 0x70}, 1},
		{{0x71, 0x81}, 0},
		{{0x70, 0x04}, 0},
		{{0x95, 0x70}, 1},
		{{0x71, 0x00}, 0},
		{{0x70, 0x08}, 0},
		{{0x95, 0x70}, 1},
		{{0x94, 0x02}, 0},
		{{0xde, 0x24}, 0},
		{{0x94, 0x02}, 0},
		{{0xdd, 0xf0}, 0},
		{{0x94, 0x02}, 0},
		{{0xe3, 0x2c}, 0},
		{{0x94, 0x02}, 0},
		{{0xe4, 0x00}, 0},
		{{0x94, 0x02}, 0},
		{{0xe5, 0x00}, 0},
		{{0x94, 0x02}, 0},
		{{0xe6, 0x2c}, 0},
		{{0x94, 0x03}, 0},
		{{0xaa, 0x00}, 0},
		{{0x71, 0x1e}, 0},
		{{0x70, 0x06}, 0},
		{{0x71, 0x80}, 0},
		{{0x70, 0x07}, 0}
	};
	for (i = 0; i < ARRAY_SIZE(start_commands); i++) {
		retval = jlj_write2(gspca_dev, start_commands[i].instruction);
		if (retval < 0)
			return retval;
		if (start_commands[i].ack_wanted)
			retval = jlj_read1(gspca_dev, response);
		if (retval < 0)
			return retval;
	}
	PDEBUG(D_ERR, "jlj_start retval is %d", retval);
	return retval;
}

static int jlj_stop(struct gspca_dev *gspca_dev)
{
	int i;
	int retval;
	struct jlj_command stop_commands[] = {
		{{0x71, 0x00}, 0},
		{{0x70, 0x09}, 0},
		{{0x71, 0x80}, 0},
		{{0x70, 0x05}, 0}
	};
	for (i = 0; i < ARRAY_SIZE(stop_commands); i++) {
		retval = jlj_write2(gspca_dev, stop_commands[i].instruction);
		if (retval < 0)
			return retval;
	}
	return retval;
}

/* 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 the gspca usb_lock is
 * used when performing the one USB control operation inside the workqueue,
 * which tells the camera to close the stream. In practice the only thing
 * which needs to be protected against is the usb_set_interface call that
 * gspca makes during stream_off. Otherwise the camera doesn't provide any
 * controls that the user could try to change.
 */

static void jlj_dostream(struct work_struct *work)
{
	struct sd *dev = container_of(work, struct sd, work_struct);
	struct gspca_dev *gspca_dev = &dev->gspca_dev;
	int blocks_left; /* 0x200-sized blocks remaining in current frame. */
	int size_in_blocks;
	int act_len;
	int packet_type;
	int ret;
	u8 *buffer;

	buffer = kmalloc(JEILINJ_MAX_TRANSFER, GFP_KERNEL | GFP_DMA);
	if (!buffer) {
		err("Couldn't allocate USB buffer");
		goto quit_stream;
	}
	while (gspca_dev->present && gspca_dev->streaming) {
		/*
		 * Now request data block 0. Line 0 reports the size
		 * to download, in blocks of size 0x200, and also tells the
		 * "actual" data size, in bytes, which seems best to ignore.
		 */
		ret = usb_bulk_msg(gspca_dev->dev,
				usb_rcvbulkpipe(gspca_dev->dev, 0x82),
				buffer, JEILINJ_MAX_TRANSFER, &act_len,
				JEILINJ_DATA_TIMEOUT);
		PDEBUG(D_STREAM,
			"Got %d bytes out of %d for Block 0",
			act_len, JEILINJ_MAX_TRANSFER);
		if (ret < 0 || act_len < FRAME_HEADER_LEN)
			goto quit_stream;
		size_in_blocks = buffer[0x0a];
		blocks_left = buffer[0x0a] - 1;
		PDEBUG(D_STREAM, "blocks_left = 0x%x", blocks_left);

		/* Start a new frame, and add the JPEG header, first thing */
		gspca_frame_add(gspca_dev, FIRST_PACKET,
				dev->jpeg_hdr, JPEG_HDR_SZ);
		/* Toss line 0 of data block 0, keep the rest. */
		gspca_frame_add(gspca_dev, INTER_PACKET,
				buffer + FRAME_HEADER_LEN,
				JEILINJ_MAX_TRANSFER - FRAME_HEADER_LEN);

		while (blocks_left > 0) {
			if (!gspca_dev->present)
				goto quit_stream;
			ret = usb_bulk_msg(gspca_dev->dev,
				usb_rcvbulkpipe(gspca_dev->dev, 0x82),
				buffer, JEILINJ_MAX_TRANSFER, &act_len,
				JEILINJ_DATA_TIMEOUT);
			if (ret < 0 || act_len < JEILINJ_MAX_TRANSFER)
				goto quit_stream;
			PDEBUG(D_STREAM,
				"%d blocks remaining for frame", blocks_left);
			blocks_left -= 1;
			if (blocks_left == 0)
				packet_type = LAST_PACKET;
			else
				packet_type = INTER_PACKET;
			gspca_frame_add(gspca_dev, packet_type,
					buffer, JEILINJ_MAX_TRANSFER);
		}
	}
quit_stream:
	mutex_lock(&gspca_dev->usb_lock);
	if (gspca_dev->present)
		jlj_stop(gspca_dev);
	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;

	dev->quality  = 85;
	dev->jpegqual = 85;
	PDEBUG(D_PROBE,
		"JEILINJ camera detected"
		" (vid/pid 0x%04X:0x%04X)", id->idVendor, id->idProduct);
	cam->cam_mode = jlj_mode;
	cam->nmodes = 1;
	cam->bulk = 1;
	/* We don't use the buffer gspca allocates so make it small. */
	cam->bulk_size = 32;
	INIT_WORK(&dev->work_struct, jlj_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 jlj_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)
{
	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;

	/* create the JPEG header */
	jpeg_define(dev->jpeg_hdr, gspca_dev->height, gspca_dev->width,
			0x21);          /* JPEG 422 */
	jpeg_set_qual(dev->jpeg_hdr, dev->quality);
	PDEBUG(D_STREAM, "Start streaming at 320x240");
	ret = jlj_start(gspca_dev);
	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 struct usb_device_id device_table[] = {
	{USB_DEVICE(0x0979, 0x0280)},
	{}
};

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)
{
	return usb_register(&sd_driver);
}

static void __exit sd_mod_exit(void)
{
	usb_deregister(&sd_driver);
}

module_init(sd_mod_init);
module_exit(sd_mod_exit);