/*
 * gspca ViCam subdriver
 *
 * Copyright (C) 2011 Hans de Goede <hdegoede@redhat.com>
 *
 * Based on the usbvideo vicam driver, which is:
 *
 * Copyright (c) 2002 Joe Burks (jburks@wavicle.org),
 *                    Chris Cheney (chris.cheney@gmail.com),
 *                    Pavel Machek (pavel@ucw.cz),
 *                    John Tyner (jtyner@cs.ucr.edu),
 *                    Monroe Williams (monroe@pobox.com)
 *
 * 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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#define MODULE_NAME "vicam"
#define HEADER_SIZE 64

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

#define VICAM_FIRMWARE "vicam/firmware.fw"

MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
MODULE_DESCRIPTION("GSPCA ViCam USB Camera Driver");
MODULE_LICENSE("GPL");
MODULE_FIRMWARE(VICAM_FIRMWARE);

struct sd {
        struct gspca_dev gspca_dev;     /* !! must be the first item */
        struct work_struct work_struct;
};

/* The vicam sensor has a resolution of 512 x 244, with I believe square
   pixels, but this is forced to a 4:3 ratio by optics. So it has
   non square pixels :( */
static struct v4l2_pix_format vicam_mode[] = {
        { 256, 122, V4L2_PIX_FMT_SGRBG8, V4L2_FIELD_NONE,
                .bytesperline = 256,
                .sizeimage = 256 * 122,
                .colorspace = V4L2_COLORSPACE_SRGB,},
        /* 2 modes with somewhat more square pixels */
        { 256, 200, V4L2_PIX_FMT_SGRBG8, V4L2_FIELD_NONE,
                .bytesperline = 256,
                .sizeimage = 256 * 200,
                .colorspace = V4L2_COLORSPACE_SRGB,},
        { 256, 240, V4L2_PIX_FMT_SGRBG8, V4L2_FIELD_NONE,
                .bytesperline = 256,
                .sizeimage = 256 * 240,
                .colorspace = V4L2_COLORSPACE_SRGB,},
#if 0   /* This mode has extremely non square pixels, testing use only */
        { 512, 122, V4L2_PIX_FMT_SGRBG8, V4L2_FIELD_NONE,
                .bytesperline = 512,
                .sizeimage = 512 * 122,
                .colorspace = V4L2_COLORSPACE_SRGB,},
#endif
        { 512, 244, V4L2_PIX_FMT_SGRBG8, V4L2_FIELD_NONE,
                .bytesperline = 512,
                .sizeimage = 512 * 244,
                .colorspace = V4L2_COLORSPACE_SRGB,},
};

static int vicam_control_msg(struct gspca_dev *gspca_dev, u8 request,
        u16 value, u16 index, u8 *data, u16 len)
{
        int ret;

        ret = usb_control_msg(gspca_dev->dev,
                              usb_sndctrlpipe(gspca_dev->dev, 0),
                              request,
                              USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
                              value, index, data, len, 1000);
        if (ret < 0)
                pr_err("control msg req %02X error %d\n", request, ret);

        return ret;
}

static int vicam_set_camera_power(struct gspca_dev *gspca_dev, int state)
{
        int ret;

        ret = vicam_control_msg(gspca_dev, 0x50, state, 0, NULL, 0);
        if (ret < 0)
                return ret;

        if (state)
                ret = vicam_control_msg(gspca_dev, 0x55, 1, 0, NULL, 0);

        return ret;
}

/*
 *  request and read a block of data
 */
static int vicam_read_frame(struct gspca_dev *gspca_dev, u8 *data, int size)
{
        int ret, unscaled_height, act_len = 0;
        u8 *req_data = gspca_dev->usb_buf;
        s32 expo = v4l2_ctrl_g_ctrl(gspca_dev->exposure);
        s32 gain = v4l2_ctrl_g_ctrl(gspca_dev->gain);

        memset(req_data, 0, 16);
        req_data[0] = gain;
        if (gspca_dev->pixfmt.width == 256)
                req_data[1] |= 0x01; /* low nibble x-scale */
        if (gspca_dev->pixfmt.height <= 122) {
                req_data[1] |= 0x10; /* high nibble y-scale */
                unscaled_height = gspca_dev->pixfmt.height * 2;
        } else
                unscaled_height = gspca_dev->pixfmt.height;
        req_data[2] = 0x90; /* unknown, does not seem to do anything */
        if (unscaled_height <= 200)
                req_data[3] = 0x06; /* vend? */
        else if (unscaled_height <= 242) /* Yes 242 not 240 */
                req_data[3] = 0x07; /* vend? */
        else /* Up to 244 lines with req_data[3] == 0x08 */
                req_data[3] = 0x08; /* vend? */

        if (expo < 256) {
                /* Frame rate maxed out, use partial frame expo time */
                req_data[4] = 255 - expo;
                req_data[5] = 0x00;
                req_data[6] = 0x00;
                req_data[7] = 0x01;
        } else {
                /* Modify frame rate */
                req_data[4] = 0x00;
                req_data[5] = 0x00;
                req_data[6] = expo & 0xFF;
                req_data[7] = expo >> 8;
        }
        req_data[8] = ((244 - unscaled_height) / 2) & ~0x01; /* vstart */
        /* bytes 9-15 do not seem to affect exposure or image quality */

        mutex_lock(&gspca_dev->usb_lock);
        ret = vicam_control_msg(gspca_dev, 0x51, 0x80, 0, req_data, 16);
        mutex_unlock(&gspca_dev->usb_lock);
        if (ret < 0)
                return ret;

        ret = usb_bulk_msg(gspca_dev->dev,
                           usb_rcvbulkpipe(gspca_dev->dev, 0x81),
                           data, size, &act_len, 10000);
        /* successful, it returns 0, otherwise  negative */
        if (ret < 0 || act_len != size) {
                pr_err("bulk read fail (%d) len %d/%d\n",
                       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 gspca_dev->usb_buf we take the usb_lock when
 * performing USB operations using it. In practice we don't really need this
 * as the cameras controls are only written from the workqueue.
 */
static void vicam_dostream(struct work_struct *work)
{
        struct sd *sd = container_of(work, struct sd, work_struct);
        struct gspca_dev *gspca_dev = &sd->gspca_dev;
        int ret, frame_sz;
        u8 *buffer;

        frame_sz = gspca_dev->cam.cam_mode[gspca_dev->curr_mode].sizeimage +
                   HEADER_SIZE;
        buffer = kmalloc(frame_sz, GFP_KERNEL | GFP_DMA);
        if (!buffer) {
                pr_err("Couldn't allocate USB buffer\n");
                goto exit;
        }

        while (gspca_dev->present && gspca_dev->streaming) {
#ifdef CONFIG_PM
                if (gspca_dev->frozen)
                        break;
#endif
                ret = vicam_read_frame(gspca_dev, buffer, frame_sz);
                if (ret < 0)
                        break;

                /* Note the frame header contents seem to be completely
                   constant, they do not change with either image, or
                   settings. So we simply discard it. The frames have
                   a very similar 64 byte footer, which we don't even
                   bother reading from the cam */
                gspca_frame_add(gspca_dev, FIRST_PACKET,
                                buffer + HEADER_SIZE,
                                frame_sz - HEADER_SIZE);
                gspca_frame_add(gspca_dev, LAST_PACKET, NULL, 0);
        }
exit:
        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 *sd = (struct sd *)gspca_dev;

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

        INIT_WORK(&sd->work_struct, vicam_dostream);

        return 0;
}

/* this function is called at probe and resume time */
static int sd_init(struct gspca_dev *gspca_dev)
{
        int ret;
        const struct ihex_binrec *rec;
        const struct firmware *uninitialized_var(fw);
        u8 *firmware_buf;

        ret = request_ihex_firmware(&fw, VICAM_FIRMWARE,
                                    &gspca_dev->dev->dev);
        if (ret) {
                pr_err("Failed to load \"vicam/firmware.fw\": %d\n", ret);
                return ret;
        }

        firmware_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
        if (!firmware_buf) {
                ret = -ENOMEM;
                goto exit;
        }
        for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) {
                memcpy(firmware_buf, rec->data, be16_to_cpu(rec->len));
                ret = vicam_control_msg(gspca_dev, 0xff, 0, 0, firmware_buf,
                                        be16_to_cpu(rec->len));
                if (ret < 0)
                        break;
        }

        kfree(firmware_buf);
exit:
        release_firmware(fw);
        return ret;
}

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

        ret = vicam_set_camera_power(gspca_dev, 1);
        if (ret < 0)
                return ret;

        schedule_work(&sd->work_struct);

        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 vicam_dostream to finish */
        flush_work(&dev->work_struct);
        mutex_lock(&gspca_dev->usb_lock);

        if (gspca_dev->present)
                vicam_set_camera_power(gspca_dev, 0);
}

static int sd_init_controls(struct gspca_dev *gspca_dev)
{
        struct v4l2_ctrl_handler *hdl = &gspca_dev->ctrl_handler;

        gspca_dev->vdev.ctrl_handler = hdl;
        v4l2_ctrl_handler_init(hdl, 2);
        gspca_dev->exposure = v4l2_ctrl_new_std(hdl, NULL,
                        V4L2_CID_EXPOSURE, 0, 2047, 1, 256);
        gspca_dev->gain = v4l2_ctrl_new_std(hdl, NULL,
                        V4L2_CID_GAIN, 0, 255, 1, 200);

        if (hdl->error) {
                pr_err("Could not initialize controls\n");
                return hdl->error;
        }
        return 0;
}

/* Table of supported USB devices */
static const struct usb_device_id device_table[] = {
        {USB_DEVICE(0x04c1, 0x009d)},
        {USB_DEVICE(0x0602, 0x1001)},
        {}
};

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,
        .init_controls = sd_init_controls,
        .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,
        .reset_resume = gspca_resume,
#endif
};

module_usb_driver(sd_driver);