/*
 * vimc-debayer.c Virtual Media Controller Driver
 *
 * Copyright (C) 2015-2017 Helen Koike <helen.fornazier@gmail.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
 * (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.
 *
 */

#include <linux/component.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/vmalloc.h>
#include <linux/v4l2-mediabus.h>
#include <media/v4l2-subdev.h>

#include "vimc-common.h"

#define VIMC_DEB_DRV_NAME "vimc-debayer"

static unsigned int deb_mean_win_size = 3;
module_param(deb_mean_win_size, uint, 0000);
MODULE_PARM_DESC(deb_mean_win_size, " the window size to calculate the mean.\n"
        "NOTE: the window size need to be an odd number, as the main pixel "
        "stays in the center of the window, otherwise the next odd number "
        "is considered");

#define IS_SINK(pad) (!pad)
#define IS_SRC(pad)  (pad)

enum vimc_deb_rgb_colors {
        VIMC_DEB_RED = 0,
        VIMC_DEB_GREEN = 1,
        VIMC_DEB_BLUE = 2,
};

struct vimc_deb_pix_map {
        u32 code;
        enum vimc_deb_rgb_colors order[2][2];
};

struct vimc_deb_device {
        struct vimc_ent_device ved;
        struct v4l2_subdev sd;
        struct device *dev;
        /* The active format */
        struct v4l2_mbus_framefmt sink_fmt;
        u32 src_code;
        void (*set_rgb_src)(struct vimc_deb_device *vdeb, unsigned int lin,
                            unsigned int col, unsigned int rgb[3]);
        /* Values calculated when the stream starts */
        u8 *src_frame;
        const struct vimc_deb_pix_map *sink_pix_map;
        unsigned int sink_bpp;
};

static const struct v4l2_mbus_framefmt sink_fmt_default = {
        .width = 640,
        .height = 480,
        .code = MEDIA_BUS_FMT_RGB888_1X24,
        .field = V4L2_FIELD_NONE,
        .colorspace = V4L2_COLORSPACE_DEFAULT,
};

static const struct vimc_deb_pix_map vimc_deb_pix_map_list[] = {
        {
                .code = MEDIA_BUS_FMT_SBGGR8_1X8,
                .order = { { VIMC_DEB_BLUE, VIMC_DEB_GREEN },
                           { VIMC_DEB_GREEN, VIMC_DEB_RED } }
        },
        {
                .code = MEDIA_BUS_FMT_SGBRG8_1X8,
                .order = { { VIMC_DEB_GREEN, VIMC_DEB_BLUE },
                           { VIMC_DEB_RED, VIMC_DEB_GREEN } }
        },
        {
                .code = MEDIA_BUS_FMT_SGRBG8_1X8,
                .order = { { VIMC_DEB_GREEN, VIMC_DEB_RED },
                           { VIMC_DEB_BLUE, VIMC_DEB_GREEN } }
        },
        {
                .code = MEDIA_BUS_FMT_SRGGB8_1X8,
                .order = { { VIMC_DEB_RED, VIMC_DEB_GREEN },
                           { VIMC_DEB_GREEN, VIMC_DEB_BLUE } }
        },
        {
                .code = MEDIA_BUS_FMT_SBGGR10_1X10,
                .order = { { VIMC_DEB_BLUE, VIMC_DEB_GREEN },
                           { VIMC_DEB_GREEN, VIMC_DEB_RED } }
        },
        {
                .code = MEDIA_BUS_FMT_SGBRG10_1X10,
                .order = { { VIMC_DEB_GREEN, VIMC_DEB_BLUE },
                           { VIMC_DEB_RED, VIMC_DEB_GREEN } }
        },
        {
                .code = MEDIA_BUS_FMT_SGRBG10_1X10,
                .order = { { VIMC_DEB_GREEN, VIMC_DEB_RED },
                           { VIMC_DEB_BLUE, VIMC_DEB_GREEN } }
        },
        {
                .code = MEDIA_BUS_FMT_SRGGB10_1X10,
                .order = { { VIMC_DEB_RED, VIMC_DEB_GREEN },
                           { VIMC_DEB_GREEN, VIMC_DEB_BLUE } }
        },
        {
                .code = MEDIA_BUS_FMT_SBGGR12_1X12,
                .order = { { VIMC_DEB_BLUE, VIMC_DEB_GREEN },
                           { VIMC_DEB_GREEN, VIMC_DEB_RED } }
        },
        {
                .code = MEDIA_BUS_FMT_SGBRG12_1X12,
                .order = { { VIMC_DEB_GREEN, VIMC_DEB_BLUE },
                           { VIMC_DEB_RED, VIMC_DEB_GREEN } }
        },
        {
                .code = MEDIA_BUS_FMT_SGRBG12_1X12,
                .order = { { VIMC_DEB_GREEN, VIMC_DEB_RED },
                           { VIMC_DEB_BLUE, VIMC_DEB_GREEN } }
        },
        {
                .code = MEDIA_BUS_FMT_SRGGB12_1X12,
                .order = { { VIMC_DEB_RED, VIMC_DEB_GREEN },
                           { VIMC_DEB_GREEN, VIMC_DEB_BLUE } }
        },
};

static const struct vimc_deb_pix_map *vimc_deb_pix_map_by_code(u32 code)
{
        unsigned int i;

        for (i = 0; i < ARRAY_SIZE(vimc_deb_pix_map_list); i++)
                if (vimc_deb_pix_map_list[i].code == code)
                        return &vimc_deb_pix_map_list[i];

        return NULL;
}

static int vimc_deb_init_cfg(struct v4l2_subdev *sd,
                             struct v4l2_subdev_pad_config *cfg)
{
        struct vimc_deb_device *vdeb = v4l2_get_subdevdata(sd);
        struct v4l2_mbus_framefmt *mf;
        unsigned int i;

        mf = v4l2_subdev_get_try_format(sd, cfg, 0);
        *mf = sink_fmt_default;

        for (i = 1; i < sd->entity.num_pads; i++) {
                mf = v4l2_subdev_get_try_format(sd, cfg, i);
                *mf = sink_fmt_default;
                mf->code = vdeb->src_code;
        }

        return 0;
}

static int vimc_deb_enum_mbus_code(struct v4l2_subdev *sd,
                                   struct v4l2_subdev_pad_config *cfg,
                                   struct v4l2_subdev_mbus_code_enum *code)
{
        /* We only support one format for source pads */
        if (IS_SRC(code->pad)) {
                struct vimc_deb_device *vdeb = v4l2_get_subdevdata(sd);

                if (code->index)
                        return -EINVAL;

                code->code = vdeb->src_code;
        } else {
                if (code->index >= ARRAY_SIZE(vimc_deb_pix_map_list))
                        return -EINVAL;

                code->code = vimc_deb_pix_map_list[code->index].code;
        }

        return 0;
}

static int vimc_deb_enum_frame_size(struct v4l2_subdev *sd,
                                    struct v4l2_subdev_pad_config *cfg,
                                    struct v4l2_subdev_frame_size_enum *fse)
{
        struct vimc_deb_device *vdeb = v4l2_get_subdevdata(sd);

        if (fse->index)
                return -EINVAL;

        if (IS_SINK(fse->pad)) {
                const struct vimc_deb_pix_map *vpix =
                        vimc_deb_pix_map_by_code(fse->code);

                if (!vpix)
                        return -EINVAL;
        } else if (fse->code != vdeb->src_code) {
                return -EINVAL;
        }

        fse->min_width = VIMC_FRAME_MIN_WIDTH;
        fse->max_width = VIMC_FRAME_MAX_WIDTH;
        fse->min_height = VIMC_FRAME_MIN_HEIGHT;
        fse->max_height = VIMC_FRAME_MAX_HEIGHT;

        return 0;
}

static int vimc_deb_get_fmt(struct v4l2_subdev *sd,
                            struct v4l2_subdev_pad_config *cfg,
                            struct v4l2_subdev_format *fmt)
{
        struct vimc_deb_device *vdeb = v4l2_get_subdevdata(sd);

        /* Get the current sink format */
        fmt->format = fmt->which == V4L2_SUBDEV_FORMAT_TRY ?
                      *v4l2_subdev_get_try_format(sd, cfg, 0) :
                      vdeb->sink_fmt;

        /* Set the right code for the source pad */
        if (IS_SRC(fmt->pad))
                fmt->format.code = vdeb->src_code;

        return 0;
}

static void vimc_deb_adjust_sink_fmt(struct v4l2_mbus_framefmt *fmt)
{
        const struct vimc_deb_pix_map *vpix;

        /* Don't accept a code that is not on the debayer table */
        vpix = vimc_deb_pix_map_by_code(fmt->code);
        if (!vpix)
                fmt->code = sink_fmt_default.code;

        fmt->width = clamp_t(u32, fmt->width, VIMC_FRAME_MIN_WIDTH,
                             VIMC_FRAME_MAX_WIDTH) & ~1;
        fmt->height = clamp_t(u32, fmt->height, VIMC_FRAME_MIN_HEIGHT,
                              VIMC_FRAME_MAX_HEIGHT) & ~1;

        if (fmt->field == V4L2_FIELD_ANY)
                fmt->field = sink_fmt_default.field;

        vimc_colorimetry_clamp(fmt);
}

static int vimc_deb_set_fmt(struct v4l2_subdev *sd,
                            struct v4l2_subdev_pad_config *cfg,
                            struct v4l2_subdev_format *fmt)
{
        struct vimc_deb_device *vdeb = v4l2_get_subdevdata(sd);
        struct v4l2_mbus_framefmt *sink_fmt;

        if (fmt->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
                /* Do not change the format while stream is on */
                if (vdeb->src_frame)
                        return -EBUSY;

                sink_fmt = &vdeb->sink_fmt;
        } else {
                sink_fmt = v4l2_subdev_get_try_format(sd, cfg, 0);
        }

        /*
         * Do not change the format of the source pad,
         * it is propagated from the sink
         */
        if (IS_SRC(fmt->pad)) {
                fmt->format = *sink_fmt;
                /* TODO: Add support for other formats */
                fmt->format.code = vdeb->src_code;
        } else {
                /* Set the new format in the sink pad */
                vimc_deb_adjust_sink_fmt(&fmt->format);

                dev_dbg(vdeb->dev, "%s: sink format update: "
                        "old:%dx%d (0x%x, %d, %d, %d, %d) "
                        "new:%dx%d (0x%x, %d, %d, %d, %d)\n", vdeb->sd.name,
                        /* old */
                        sink_fmt->width, sink_fmt->height, sink_fmt->code,
                        sink_fmt->colorspace, sink_fmt->quantization,
                        sink_fmt->xfer_func, sink_fmt->ycbcr_enc,
                        /* new */
                        fmt->format.width, fmt->format.height, fmt->format.code,
                        fmt->format.colorspace, fmt->format.quantization,
                        fmt->format.xfer_func, fmt->format.ycbcr_enc);

                *sink_fmt = fmt->format;
        }

        return 0;
}

static const struct v4l2_subdev_pad_ops vimc_deb_pad_ops = {
        .init_cfg               = vimc_deb_init_cfg,
        .enum_mbus_code         = vimc_deb_enum_mbus_code,
        .enum_frame_size        = vimc_deb_enum_frame_size,
        .get_fmt                = vimc_deb_get_fmt,
        .set_fmt                = vimc_deb_set_fmt,
};

static void vimc_deb_set_rgb_mbus_fmt_rgb888_1x24(struct vimc_deb_device *vdeb,
                                                  unsigned int lin,
                                                  unsigned int col,
                                                  unsigned int rgb[3])
{
        unsigned int i, index;

        index = VIMC_FRAME_INDEX(lin, col, vdeb->sink_fmt.width, 3);
        for (i = 0; i < 3; i++)
                vdeb->src_frame[index + i] = rgb[i];
}

static int vimc_deb_s_stream(struct v4l2_subdev *sd, int enable)
{
        struct vimc_deb_device *vdeb = v4l2_get_subdevdata(sd);
        int ret;

        if (enable) {
                const struct vimc_pix_map *vpix;
                unsigned int frame_size;

                if (vdeb->src_frame)
                        return 0;

                /* Calculate the frame size of the source pad */
                vpix = vimc_pix_map_by_code(vdeb->src_code);
                frame_size = vdeb->sink_fmt.width * vdeb->sink_fmt.height *
                                vpix->bpp;

                /* Save the bytes per pixel of the sink */
                vpix = vimc_pix_map_by_code(vdeb->sink_fmt.code);
                vdeb->sink_bpp = vpix->bpp;

                /* Get the corresponding pixel map from the table */
                vdeb->sink_pix_map =
                        vimc_deb_pix_map_by_code(vdeb->sink_fmt.code);

                /*
                 * Allocate the frame buffer. Use vmalloc to be able to
                 * allocate a large amount of memory
                 */
                vdeb->src_frame = vmalloc(frame_size);
                if (!vdeb->src_frame)
                        return -ENOMEM;

                /* Turn the stream on in the subdevices directly connected */
                ret = vimc_pipeline_s_stream(&vdeb->sd.entity, 1);
                if (ret) {
                        vfree(vdeb->src_frame);
                        vdeb->src_frame = NULL;
                        return ret;
                }
        } else {
                if (!vdeb->src_frame)
                        return 0;

                /* Disable streaming from the pipe */
                ret = vimc_pipeline_s_stream(&vdeb->sd.entity, 0);
                if (ret)
                        return ret;

                vfree(vdeb->src_frame);
                vdeb->src_frame = NULL;
        }

        return 0;
}

static const struct v4l2_subdev_video_ops vimc_deb_video_ops = {
        .s_stream = vimc_deb_s_stream,
};

static const struct v4l2_subdev_ops vimc_deb_ops = {
        .pad = &vimc_deb_pad_ops,
        .video = &vimc_deb_video_ops,
};

static unsigned int vimc_deb_get_val(const u8 *bytes,
                                     const unsigned int n_bytes)
{
        unsigned int i;
        unsigned int acc = 0;

        for (i = 0; i < n_bytes; i++)
                acc = acc + (bytes[i] << (8 * i));

        return acc;
}

static void vimc_deb_calc_rgb_sink(struct vimc_deb_device *vdeb,
                                   const u8 *frame,
                                   const unsigned int lin,
                                   const unsigned int col,
                                   unsigned int rgb[3])
{
        unsigned int i, seek, wlin, wcol;
        unsigned int n_rgb[3] = {0, 0, 0};

        for (i = 0; i < 3; i++)
                rgb[i] = 0;

        /*
         * Calculate how many we need to subtract to get to the pixel in
         * the top left corner of the mean window (considering the current
         * pixel as the center)
         */
        seek = deb_mean_win_size / 2;

        /* Sum the values of the colors in the mean window */

        dev_dbg(vdeb->dev,
                "deb: %s: --- Calc pixel %dx%d, window mean %d, seek %d ---\n",
                vdeb->sd.name, lin, col, vdeb->sink_fmt.height, seek);

        /*
         * Iterate through all the lines in the mean window, start
         * with zero if the pixel is outside the frame and don't pass
         * the height when the pixel is in the bottom border of the
         * frame
         */
        for (wlin = seek > lin ? 0 : lin - seek;
             wlin < lin + seek + 1 && wlin < vdeb->sink_fmt.height;
             wlin++) {

                /*
                 * Iterate through all the columns in the mean window, start
                 * with zero if the pixel is outside the frame and don't pass
                 * the width when the pixel is in the right border of the
                 * frame
                 */
                for (wcol = seek > col ? 0 : col - seek;
                     wcol < col + seek + 1 && wcol < vdeb->sink_fmt.width;
                     wcol++) {
                        enum vimc_deb_rgb_colors color;
                        unsigned int index;

                        /* Check which color this pixel is */
                        color = vdeb->sink_pix_map->order[wlin % 2][wcol % 2];

                        index = VIMC_FRAME_INDEX(wlin, wcol,
                                                 vdeb->sink_fmt.width,
                                                 vdeb->sink_bpp);

                        dev_dbg(vdeb->dev,
                                "deb: %s: RGB CALC: frame index %d, win pos %dx%d, color %d\n",
                                vdeb->sd.name, index, wlin, wcol, color);

                        /* Get its value */
                        rgb[color] = rgb[color] +
                                vimc_deb_get_val(&frame[index], vdeb->sink_bpp);

                        /* Save how many values we already added */
                        n_rgb[color]++;

                        dev_dbg(vdeb->dev, "deb: %s: RGB CALC: val %d, n %d\n",
                                vdeb->sd.name, rgb[color], n_rgb[color]);
                }
        }

        /* Calculate the mean */
        for (i = 0; i < 3; i++) {
                dev_dbg(vdeb->dev,
                        "deb: %s: PRE CALC: %dx%d Color %d, val %d, n %d\n",
                        vdeb->sd.name, lin, col, i, rgb[i], n_rgb[i]);

                if (n_rgb[i])
                        rgb[i] = rgb[i] / n_rgb[i];

                dev_dbg(vdeb->dev,
                        "deb: %s: FINAL CALC: %dx%d Color %d, val %d\n",
                        vdeb->sd.name, lin, col, i, rgb[i]);
        }
}

static void vimc_deb_process_frame(struct vimc_ent_device *ved,
                                   struct media_pad *sink,
                                   const void *sink_frame)
{
        struct vimc_deb_device *vdeb = container_of(ved, struct vimc_deb_device,
                                                    ved);
        unsigned int rgb[3];
        unsigned int i, j;

        /* If the stream in this node is not active, just return */
        if (!vdeb->src_frame)
                return;

        for (i = 0; i < vdeb->sink_fmt.height; i++)
                for (j = 0; j < vdeb->sink_fmt.width; j++) {
                        vimc_deb_calc_rgb_sink(vdeb, sink_frame, i, j, rgb);
                        vdeb->set_rgb_src(vdeb, i, j, rgb);
                }

        /* Propagate the frame through all source pads */
        for (i = 1; i < vdeb->sd.entity.num_pads; i++) {
                struct media_pad *pad = &vdeb->sd.entity.pads[i];

                vimc_propagate_frame(pad, vdeb->src_frame);
        }
}

static void vimc_deb_comp_unbind(struct device *comp, struct device *master,
                                 void *master_data)
{
        struct vimc_ent_device *ved = dev_get_drvdata(comp);
        struct vimc_deb_device *vdeb = container_of(ved, struct vimc_deb_device,
                                                    ved);

        vimc_ent_sd_unregister(ved, &vdeb->sd);
        kfree(vdeb);
}

static int vimc_deb_comp_bind(struct device *comp, struct device *master,
                              void *master_data)
{
        struct v4l2_device *v4l2_dev = master_data;
        struct vimc_platform_data *pdata = comp->platform_data;
        struct vimc_deb_device *vdeb;
        int ret;

        /* Allocate the vdeb struct */
        vdeb = kzalloc(sizeof(*vdeb), GFP_KERNEL);
        if (!vdeb)
                return -ENOMEM;

        /* Initialize ved and sd */
        ret = vimc_ent_sd_register(&vdeb->ved, &vdeb->sd, v4l2_dev,
                                   pdata->entity_name,
                                   MEDIA_ENT_F_ATV_DECODER, 2,
                                   (const unsigned long[2]) {MEDIA_PAD_FL_SINK,
                                   MEDIA_PAD_FL_SOURCE},
                                   &vimc_deb_ops);
        if (ret) {
                kfree(vdeb);
                return ret;
        }

        vdeb->ved.process_frame = vimc_deb_process_frame;
        dev_set_drvdata(comp, &vdeb->ved);
        vdeb->dev = comp;

        /* Initialize the frame format */
        vdeb->sink_fmt = sink_fmt_default;
        /*
         * TODO: Add support for more output formats, we only support
         * RGB888 for now
         * NOTE: the src format is always the same as the sink, except
         * for the code
         */
        vdeb->src_code = MEDIA_BUS_FMT_RGB888_1X24;
        vdeb->set_rgb_src = vimc_deb_set_rgb_mbus_fmt_rgb888_1x24;

        return 0;
}

static const struct component_ops vimc_deb_comp_ops = {
        .bind = vimc_deb_comp_bind,
        .unbind = vimc_deb_comp_unbind,
};

static int vimc_deb_probe(struct platform_device *pdev)
{
        return component_add(&pdev->dev, &vimc_deb_comp_ops);
}

static int vimc_deb_remove(struct platform_device *pdev)
{
        component_del(&pdev->dev, &vimc_deb_comp_ops);

        return 0;
}

static const struct platform_device_id vimc_deb_driver_ids[] = {
        {
                .name           = VIMC_DEB_DRV_NAME,
        },
        { }
};

static struct platform_driver vimc_deb_pdrv = {
        .probe          = vimc_deb_probe,
        .remove         = vimc_deb_remove,
        .id_table       = vimc_deb_driver_ids,
        .driver         = {
                .name   = VIMC_DEB_DRV_NAME,
        },
};

module_platform_driver(vimc_deb_pdrv);

MODULE_DEVICE_TABLE(platform, vimc_deb_driver_ids);

MODULE_DESCRIPTION("Virtual Media Controller Driver (VIMC) Debayer");
MODULE_AUTHOR("Helen Mae Koike Fornazier <helen.fornazier@gmail.com>");
MODULE_LICENSE("GPL");