/*
 * vimc-scaler.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/mod_devicetable.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_SCA_DRV_NAME "vimc-scaler"

static unsigned int sca_mult = 3;
module_param(sca_mult, uint, 0000);
MODULE_PARM_DESC(sca_mult, " the image size multiplier");

#define IS_SINK(pad)    (!pad)
#define IS_SRC(pad)     (pad)
#define MAX_ZOOM        8

struct vimc_sca_device {
        struct vimc_ent_device ved;
        struct v4l2_subdev sd;
        struct device *dev;
        /* NOTE: the source fmt is the same as the sink
         * with the width and hight multiplied by mult
         */
        struct v4l2_mbus_framefmt sink_fmt;
        /* Values calculated when the stream starts */
        u8 *src_frame;
        unsigned int src_line_size;
        unsigned int 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 int vimc_sca_init_cfg(struct v4l2_subdev *sd,
                             struct v4l2_subdev_pad_config *cfg)
{
        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->width = mf->width * sca_mult;
                mf->height = mf->height * sca_mult;
        }

        return 0;
}

static int vimc_sca_enum_mbus_code(struct v4l2_subdev *sd,
                                   struct v4l2_subdev_pad_config *cfg,
                                   struct v4l2_subdev_mbus_code_enum *code)
{
        const struct vimc_pix_map *vpix = vimc_pix_map_by_index(code->index);

        /* We don't support bayer format */
        if (!vpix || vpix->bayer)
                return -EINVAL;

        code->code = vpix->code;

        return 0;
}

static int vimc_sca_enum_frame_size(struct v4l2_subdev *sd,
                                    struct v4l2_subdev_pad_config *cfg,
                                    struct v4l2_subdev_frame_size_enum *fse)
{
        const struct vimc_pix_map *vpix;

        if (fse->index)
                return -EINVAL;

        /* Only accept code in the pix map table in non bayer format */
        vpix = vimc_pix_map_by_code(fse->code);
        if (!vpix || vpix->bayer)
                return -EINVAL;

        fse->min_width = VIMC_FRAME_MIN_WIDTH;
        fse->min_height = VIMC_FRAME_MIN_HEIGHT;

        if (IS_SINK(fse->pad)) {
                fse->max_width = VIMC_FRAME_MAX_WIDTH;
                fse->max_height = VIMC_FRAME_MAX_HEIGHT;
        } else {
                fse->max_width = VIMC_FRAME_MAX_WIDTH * MAX_ZOOM;
                fse->max_height = VIMC_FRAME_MAX_HEIGHT * MAX_ZOOM;
        }

        return 0;
}

static int vimc_sca_get_fmt(struct v4l2_subdev *sd,
                            struct v4l2_subdev_pad_config *cfg,
                            struct v4l2_subdev_format *format)
{
        struct vimc_sca_device *vsca = v4l2_get_subdevdata(sd);

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

        /* Scale the frame size for the source pad */
        if (IS_SRC(format->pad)) {
                format->format.width = vsca->sink_fmt.width * sca_mult;
                format->format.height = vsca->sink_fmt.height * sca_mult;
        }

        return 0;
}

static void vimc_sca_adjust_sink_fmt(struct v4l2_mbus_framefmt *fmt)
{
        const struct vimc_pix_map *vpix;

        /* Only accept code in the pix map table in non bayer format */
        vpix = vimc_pix_map_by_code(fmt->code);
        if (!vpix || vpix->bayer)
                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_sca_set_fmt(struct v4l2_subdev *sd,
                            struct v4l2_subdev_pad_config *cfg,
                            struct v4l2_subdev_format *fmt)
{
        struct vimc_sca_device *vsca = 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 (vsca->src_frame)
                        return -EBUSY;

                sink_fmt = &vsca->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;
                fmt->format.width = sink_fmt->width * sca_mult;
                fmt->format.height = sink_fmt->height * sca_mult;
        } else {
                /* Set the new format in the sink pad */
                vimc_sca_adjust_sink_fmt(&fmt->format);

                dev_dbg(vsca->dev, "%s: sink format update: "
                        "old:%dx%d (0x%x, %d, %d, %d, %d) "
                        "new:%dx%d (0x%x, %d, %d, %d, %d)\n", vsca->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_sca_pad_ops = {
        .init_cfg               = vimc_sca_init_cfg,
        .enum_mbus_code         = vimc_sca_enum_mbus_code,
        .enum_frame_size        = vimc_sca_enum_frame_size,
        .get_fmt                = vimc_sca_get_fmt,
        .set_fmt                = vimc_sca_set_fmt,
};

static int vimc_sca_s_stream(struct v4l2_subdev *sd, int enable)
{
        struct vimc_sca_device *vsca = v4l2_get_subdevdata(sd);
        int ret;

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

                if (vsca->src_frame)
                        return 0;

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

                /* Calculate the width in bytes of the src frame */
                vsca->src_line_size = vsca->sink_fmt.width *
                                      sca_mult * vsca->bpp;

                /* Calculate the frame size of the source pad */
                frame_size = vsca->src_line_size * vsca->sink_fmt.height *
                             sca_mult;

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

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

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

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

        return 0;
}

static const struct v4l2_subdev_video_ops vimc_sca_video_ops = {
        .s_stream = vimc_sca_s_stream,
};

static const struct v4l2_subdev_ops vimc_sca_ops = {
        .pad = &vimc_sca_pad_ops,
        .video = &vimc_sca_video_ops,
};

static void vimc_sca_fill_pix(u8 *const ptr,
                              const u8 *const pixel,
                              const unsigned int bpp)
{
        unsigned int i;

        /* copy the pixel to the pointer */
        for (i = 0; i < bpp; i++)
                ptr[i] = pixel[i];
}

static void vimc_sca_scale_pix(const struct vimc_sca_device *const vsca,
                               const unsigned int lin, const unsigned int col,
                               const u8 *const sink_frame)
{
        unsigned int i, j, index;
        const u8 *pixel;

        /* Point to the pixel value in position (lin, col) in the sink frame */
        index = VIMC_FRAME_INDEX(lin, col,
                                 vsca->sink_fmt.width,
                                 vsca->bpp);
        pixel = &sink_frame[index];

        dev_dbg(vsca->dev,
                "sca: %s: --- scale_pix sink pos %dx%d, index %d ---\n",
                vsca->sd.name, lin, col, index);

        /* point to the place we are going to put the first pixel
         * in the scaled src frame
         */
        index = VIMC_FRAME_INDEX(lin * sca_mult, col * sca_mult,
                                 vsca->sink_fmt.width * sca_mult, vsca->bpp);

        dev_dbg(vsca->dev, "sca: %s: scale_pix src pos %dx%d, index %d\n",
                vsca->sd.name, lin * sca_mult, col * sca_mult, index);

        /* Repeat this pixel mult times */
        for (i = 0; i < sca_mult; i++) {
                /* Iterate through each beginning of a
                 * pixel repetition in a line
                 */
                for (j = 0; j < sca_mult * vsca->bpp; j += vsca->bpp) {
                        dev_dbg(vsca->dev,
                                "sca: %s: sca: scale_pix src pos %d\n",
                                vsca->sd.name, index + j);

                        /* copy the pixel to the position index + j */
                        vimc_sca_fill_pix(&vsca->src_frame[index + j],
                                          pixel, vsca->bpp);
                }

                /* move the index to the next line */
                index += vsca->src_line_size;
        }
}

static void vimc_sca_fill_src_frame(const struct vimc_sca_device *const vsca,
                                    const u8 *const sink_frame)
{
        unsigned int i, j;

        /* Scale each pixel from the original sink frame */
        /* TODO: implement scale down, only scale up is supported for now */
        for (i = 0; i < vsca->sink_fmt.height; i++)
                for (j = 0; j < vsca->sink_fmt.width; j++)
                        vimc_sca_scale_pix(vsca, i, j, sink_frame);
}

static void vimc_sca_process_frame(struct vimc_ent_device *ved,
                                   struct media_pad *sink,
                                   const void *sink_frame)
{
        struct vimc_sca_device *vsca = container_of(ved, struct vimc_sca_device,
                                                    ved);
        unsigned int i;

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

        vimc_sca_fill_src_frame(vsca, sink_frame);

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

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

static void vimc_sca_comp_unbind(struct device *comp, struct device *master,
                                 void *master_data)
{
        struct vimc_ent_device *ved = dev_get_drvdata(comp);
        struct vimc_sca_device *vsca = container_of(ved, struct vimc_sca_device,
                                                    ved);

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


static int vimc_sca_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_sca_device *vsca;
        int ret;

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

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

        vsca->ved.process_frame = vimc_sca_process_frame;
        dev_set_drvdata(comp, &vsca->ved);
        vsca->dev = comp;

        /* Initialize the frame format */
        vsca->sink_fmt = sink_fmt_default;

        return 0;
}

static const struct component_ops vimc_sca_comp_ops = {
        .bind = vimc_sca_comp_bind,
        .unbind = vimc_sca_comp_unbind,
};

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

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

        return 0;
}

static const struct platform_device_id vimc_sca_driver_ids[] = {
        {
                .name           = VIMC_SCA_DRV_NAME,
        },
        { }
};

static struct platform_driver vimc_sca_pdrv = {
        .probe          = vimc_sca_probe,
        .remove         = vimc_sca_remove,
        .id_table       = vimc_sca_driver_ids,
        .driver         = {
                .name   = VIMC_SCA_DRV_NAME,
        },
};

module_platform_driver(vimc_sca_pdrv);

MODULE_DEVICE_TABLE(platform, vimc_sca_driver_ids);

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