/*
 * Copyright 2016 Advanced Micro Devices, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Authors: AMD
 *
 */

#include <linux/mm.h>
#include <linux/slab.h>

#include "dc.h"
#include "opp.h"
#include "color_gamma.h"


#define NUM_PTS_IN_REGION 16
#define NUM_REGIONS 32
#define MAX_HW_POINTS (NUM_PTS_IN_REGION*NUM_REGIONS)

static struct hw_x_point coordinates_x[MAX_HW_POINTS + 2];

static struct fixed31_32 pq_table[MAX_HW_POINTS + 2];
static struct fixed31_32 de_pq_table[MAX_HW_POINTS + 2];

static bool pq_initialized; /* = false; */
static bool de_pq_initialized; /* = false; */

/* one-time setup of X points */
void setup_x_points_distribution(void)
{
        struct fixed31_32 region_size = dc_fixpt_from_int(128);
        int32_t segment;
        uint32_t seg_offset;
        uint32_t index;
        struct fixed31_32 increment;

        coordinates_x[MAX_HW_POINTS].x = region_size;
        coordinates_x[MAX_HW_POINTS + 1].x = region_size;

        for (segment = 6; segment > (6 - NUM_REGIONS); segment--) {
                region_size = dc_fixpt_div_int(region_size, 2);
                increment = dc_fixpt_div_int(region_size,
                                                NUM_PTS_IN_REGION);
                seg_offset = (segment + (NUM_REGIONS - 7)) * NUM_PTS_IN_REGION;
                coordinates_x[seg_offset].x = region_size;

                for (index = seg_offset + 1;
                                index < seg_offset + NUM_PTS_IN_REGION;
                                index++) {
                        coordinates_x[index].x = dc_fixpt_add
                                        (coordinates_x[index-1].x, increment);
                }
        }
}

static void compute_pq(struct fixed31_32 in_x, struct fixed31_32 *out_y)
{
        /* consts for PQ gamma formula. */
        const struct fixed31_32 m1 =
                dc_fixpt_from_fraction(159301758, 1000000000);
        const struct fixed31_32 m2 =
                dc_fixpt_from_fraction(7884375, 100000);
        const struct fixed31_32 c1 =
                dc_fixpt_from_fraction(8359375, 10000000);
        const struct fixed31_32 c2 =
                dc_fixpt_from_fraction(188515625, 10000000);
        const struct fixed31_32 c3 =
                dc_fixpt_from_fraction(186875, 10000);

        struct fixed31_32 l_pow_m1;
        struct fixed31_32 base;

        if (dc_fixpt_lt(in_x, dc_fixpt_zero))
                in_x = dc_fixpt_zero;

        l_pow_m1 = dc_fixpt_pow(in_x, m1);
        base = dc_fixpt_div(
                        dc_fixpt_add(c1,
                                        (dc_fixpt_mul(c2, l_pow_m1))),
                        dc_fixpt_add(dc_fixpt_one,
                                        (dc_fixpt_mul(c3, l_pow_m1))));
        *out_y = dc_fixpt_pow(base, m2);
}

static void compute_de_pq(struct fixed31_32 in_x, struct fixed31_32 *out_y)
{
        /* consts for dePQ gamma formula. */
        const struct fixed31_32 m1 =
                dc_fixpt_from_fraction(159301758, 1000000000);
        const struct fixed31_32 m2 =
                dc_fixpt_from_fraction(7884375, 100000);
        const struct fixed31_32 c1 =
                dc_fixpt_from_fraction(8359375, 10000000);
        const struct fixed31_32 c2 =
                dc_fixpt_from_fraction(188515625, 10000000);
        const struct fixed31_32 c3 =
                dc_fixpt_from_fraction(186875, 10000);

        struct fixed31_32 l_pow_m1;
        struct fixed31_32 base, div;


        if (dc_fixpt_lt(in_x, dc_fixpt_zero))
                in_x = dc_fixpt_zero;

        l_pow_m1 = dc_fixpt_pow(in_x,
                        dc_fixpt_div(dc_fixpt_one, m2));
        base = dc_fixpt_sub(l_pow_m1, c1);

        if (dc_fixpt_lt(base, dc_fixpt_zero))
                base = dc_fixpt_zero;

        div = dc_fixpt_sub(c2, dc_fixpt_mul(c3, l_pow_m1));

        *out_y = dc_fixpt_pow(dc_fixpt_div(base, div),
                        dc_fixpt_div(dc_fixpt_one, m1));

}

/*de gamma, none linear to linear*/
static void compute_hlg_oetf(struct fixed31_32 in_x, bool is_light0_12, struct fixed31_32 *out_y)
{
        struct fixed31_32 a;
        struct fixed31_32 b;
        struct fixed31_32 c;
        struct fixed31_32 threshold;
        struct fixed31_32 reference_white_level;

        a = dc_fixpt_from_fraction(17883277, 100000000);
        if (is_light0_12) {
                /*light 0-12*/
                b = dc_fixpt_from_fraction(28466892, 100000000);
                c = dc_fixpt_from_fraction(55991073, 100000000);
                threshold = dc_fixpt_one;
                reference_white_level = dc_fixpt_half;
        } else {
                /*light 0-1*/
                b = dc_fixpt_from_fraction(2372241, 100000000);
                c = dc_fixpt_add(dc_fixpt_one, dc_fixpt_from_fraction(429347, 100000000));
                threshold = dc_fixpt_from_fraction(1, 12);
                reference_white_level = dc_fixpt_pow(dc_fixpt_from_fraction(3, 1), dc_fixpt_half);
        }
        if (dc_fixpt_lt(threshold, in_x))
                *out_y = dc_fixpt_add(c, dc_fixpt_mul(a, dc_fixpt_log(dc_fixpt_sub(in_x, b))));
        else
                *out_y = dc_fixpt_mul(dc_fixpt_pow(in_x, dc_fixpt_half), reference_white_level);
}

/*re gamma, linear to none linear*/
static void compute_hlg_eotf(struct fixed31_32 in_x, bool is_light0_12, struct fixed31_32 *out_y)
{
        struct fixed31_32 a;
        struct fixed31_32 b;
        struct fixed31_32 c;
        struct fixed31_32 reference_white_level;

        a = dc_fixpt_from_fraction(17883277, 100000000);
        if (is_light0_12) {
                /*light 0-12*/
                b = dc_fixpt_from_fraction(28466892, 100000000);
                c = dc_fixpt_from_fraction(55991073, 100000000);
                reference_white_level = dc_fixpt_from_fraction(4, 1);
        } else {
                /*light 0-1*/
                b = dc_fixpt_from_fraction(2372241, 100000000);
                c = dc_fixpt_add(dc_fixpt_one, dc_fixpt_from_fraction(429347, 100000000));
                reference_white_level = dc_fixpt_from_fraction(1, 3);
        }
        if (dc_fixpt_lt(dc_fixpt_half, in_x))
                *out_y = dc_fixpt_add(dc_fixpt_exp(dc_fixpt_div(dc_fixpt_sub(in_x, c), a)), b);
        else
                *out_y = dc_fixpt_mul(dc_fixpt_pow(in_x, dc_fixpt_from_fraction(2, 1)), reference_white_level);
}


/* one-time pre-compute PQ values - only for sdr_white_level 80 */
void precompute_pq(void)
{
        int i;
        struct fixed31_32 x;
        const struct hw_x_point *coord_x = coordinates_x + 32;
        struct fixed31_32 scaling_factor =
                        dc_fixpt_from_fraction(80, 10000);

        /* pow function has problems with arguments too small */
        for (i = 0; i < 32; i++)
                pq_table[i] = dc_fixpt_zero;

        for (i = 32; i <= MAX_HW_POINTS; i++) {
                x = dc_fixpt_mul(coord_x->x, scaling_factor);
                compute_pq(x, &pq_table[i]);
                ++coord_x;
        }
}

/* one-time pre-compute dePQ values - only for max pixel value 125 FP16 */
void precompute_de_pq(void)
{
        int i;
        struct fixed31_32  y;
        uint32_t begin_index, end_index;

        struct fixed31_32 scaling_factor = dc_fixpt_from_int(125);

        /* X points is 2^-25 to 2^7
         * De-gamma X is 2^-12 to 2^0 – we are skipping first -12-(-25) = 13 regions
         */
        begin_index = 13 * NUM_PTS_IN_REGION;
        end_index = begin_index + 12 * NUM_PTS_IN_REGION;

        for (i = 0; i <= begin_index; i++)
                de_pq_table[i] = dc_fixpt_zero;

        for (; i <= end_index; i++) {
                compute_de_pq(coordinates_x[i].x, &y);
                de_pq_table[i] = dc_fixpt_mul(y, scaling_factor);
        }

        for (; i <= MAX_HW_POINTS; i++)
                de_pq_table[i] = de_pq_table[i-1];
}
struct dividers {
        struct fixed31_32 divider1;
        struct fixed31_32 divider2;
        struct fixed31_32 divider3;
};

enum gamma_type_index {
        gamma_type_index_2_4,
        gamma_type_index_2_2,
        gamma_type_index_2_2_flat
};

static void build_coefficients(struct gamma_coefficients *coefficients, enum gamma_type_index type)
{
        static const int32_t numerator01[] = { 31308,   180000, 0};
        static const int32_t numerator02[] = { 12920,   4500,   0};
        static const int32_t numerator03[] = { 55,              99,             0};
        static const int32_t numerator04[] = { 55,              99,             0};
        static const int32_t numerator05[] = { 2400,    2200, 2200};

        uint32_t i = 0;
        uint32_t index = 0;

        if (type == gamma_type_index_2_2)
                index = 1;
        else if (type == gamma_type_index_2_2_flat)
                index = 2;

        do {
                coefficients->a0[i] = dc_fixpt_from_fraction(
                        numerator01[index], 10000000);
                coefficients->a1[i] = dc_fixpt_from_fraction(
                        numerator02[index], 1000);
                coefficients->a2[i] = dc_fixpt_from_fraction(
                        numerator03[index], 1000);
                coefficients->a3[i] = dc_fixpt_from_fraction(
                        numerator04[index], 1000);
                coefficients->user_gamma[i] = dc_fixpt_from_fraction(
                        numerator05[index], 1000);

                ++i;
        } while (i != ARRAY_SIZE(coefficients->a0));
}

static struct fixed31_32 translate_from_linear_space(
        struct fixed31_32 arg,
        struct fixed31_32 a0,
        struct fixed31_32 a1,
        struct fixed31_32 a2,
        struct fixed31_32 a3,
        struct fixed31_32 gamma)
{
        const struct fixed31_32 one = dc_fixpt_from_int(1);

        if (dc_fixpt_lt(one, arg))
                return one;

        if (dc_fixpt_le(arg, dc_fixpt_neg(a0)))
                return dc_fixpt_sub(
                        a2,
                        dc_fixpt_mul(
                                dc_fixpt_add(
                                        one,
                                        a3),
                                dc_fixpt_pow(
                                        dc_fixpt_neg(arg),
                                        dc_fixpt_recip(gamma))));
        else if (dc_fixpt_le(a0, arg))
                return dc_fixpt_sub(
                        dc_fixpt_mul(
                                dc_fixpt_add(
                                        one,
                                        a3),
                                dc_fixpt_pow(
                                        arg,
                                        dc_fixpt_recip(gamma))),
                        a2);
        else
                return dc_fixpt_mul(
                        arg,
                        a1);
}

static struct fixed31_32 calculate_gamma22(struct fixed31_32 arg)
{
        struct fixed31_32 gamma = dc_fixpt_from_fraction(22, 10);

        return translate_from_linear_space(arg,
                        dc_fixpt_zero,
                        dc_fixpt_zero,
                        dc_fixpt_zero,
                        dc_fixpt_zero,
                        gamma);
}

static struct fixed31_32 translate_to_linear_space(
        struct fixed31_32 arg,
        struct fixed31_32 a0,
        struct fixed31_32 a1,
        struct fixed31_32 a2,
        struct fixed31_32 a3,
        struct fixed31_32 gamma)
{
        struct fixed31_32 linear;

        a0 = dc_fixpt_mul(a0, a1);
        if (dc_fixpt_le(arg, dc_fixpt_neg(a0)))

                linear = dc_fixpt_neg(
                                 dc_fixpt_pow(
                                 dc_fixpt_div(
                                 dc_fixpt_sub(a2, arg),
                                 dc_fixpt_add(
                                 dc_fixpt_one, a3)), gamma));

        else if (dc_fixpt_le(dc_fixpt_neg(a0), arg) &&
                         dc_fixpt_le(arg, a0))
                linear = dc_fixpt_div(arg, a1);
        else
                linear =  dc_fixpt_pow(
                                        dc_fixpt_div(
                                        dc_fixpt_add(a2, arg),
                                        dc_fixpt_add(
                                        dc_fixpt_one, a3)), gamma);

        return linear;
}

static inline struct fixed31_32 translate_from_linear_space_ex(
        struct fixed31_32 arg,
        struct gamma_coefficients *coeff,
        uint32_t color_index)
{
        return translate_from_linear_space(
                arg,
                coeff->a0[color_index],
                coeff->a1[color_index],
                coeff->a2[color_index],
                coeff->a3[color_index],
                coeff->user_gamma[color_index]);
}


static inline struct fixed31_32 translate_to_linear_space_ex(
        struct fixed31_32 arg,
        struct gamma_coefficients *coeff,
        uint32_t color_index)
{
        return translate_to_linear_space(
                arg,
                coeff->a0[color_index],
                coeff->a1[color_index],
                coeff->a2[color_index],
                coeff->a3[color_index],
                coeff->user_gamma[color_index]);
}


static bool find_software_points(
        const struct dc_gamma *ramp,
        const struct gamma_pixel *axis_x,
        struct fixed31_32 hw_point,
        enum channel_name channel,
        uint32_t *index_to_start,
        uint32_t *index_left,
        uint32_t *index_right,
        enum hw_point_position *pos)
{
        const uint32_t max_number = ramp->num_entries + 3;

        struct fixed31_32 left, right;

        uint32_t i = *index_to_start;

        while (i < max_number) {
                if (channel == CHANNEL_NAME_RED) {
                        left = axis_x[i].r;

                        if (i < max_number - 1)
                                right = axis_x[i + 1].r;
                        else
                                right = axis_x[max_number - 1].r;
                } else if (channel == CHANNEL_NAME_GREEN) {
                        left = axis_x[i].g;

                        if (i < max_number - 1)
                                right = axis_x[i + 1].g;
                        else
                                right = axis_x[max_number - 1].g;
                } else {
                        left = axis_x[i].b;

                        if (i < max_number - 1)
                                right = axis_x[i + 1].b;
                        else
                                right = axis_x[max_number - 1].b;
                }

                if (dc_fixpt_le(left, hw_point) &&
                        dc_fixpt_le(hw_point, right)) {
                        *index_to_start = i;
                        *index_left = i;

                        if (i < max_number - 1)
                                *index_right = i + 1;
                        else
                                *index_right = max_number - 1;

                        *pos = HW_POINT_POSITION_MIDDLE;

                        return true;
                } else if ((i == *index_to_start) &&
                        dc_fixpt_le(hw_point, left)) {
                        *index_to_start = i;
                        *index_left = i;
                        *index_right = i;

                        *pos = HW_POINT_POSITION_LEFT;

                        return true;
                } else if ((i == max_number - 1) &&
                        dc_fixpt_le(right, hw_point)) {
                        *index_to_start = i;
                        *index_left = i;
                        *index_right = i;

                        *pos = HW_POINT_POSITION_RIGHT;

                        return true;
                }

                ++i;
        }

        return false;
}

static bool build_custom_gamma_mapping_coefficients_worker(
        const struct dc_gamma *ramp,
        struct pixel_gamma_point *coeff,
        const struct hw_x_point *coordinates_x,
        const struct gamma_pixel *axis_x,
        enum channel_name channel,
        uint32_t number_of_points)
{
        uint32_t i = 0;

        while (i <= number_of_points) {
                struct fixed31_32 coord_x;

                uint32_t index_to_start = 0;
                uint32_t index_left = 0;
                uint32_t index_right = 0;

                enum hw_point_position hw_pos;

                struct gamma_point *point;

                struct fixed31_32 left_pos;
                struct fixed31_32 right_pos;

                if (channel == CHANNEL_NAME_RED)
                        coord_x = coordinates_x[i].regamma_y_red;
                else if (channel == CHANNEL_NAME_GREEN)
                        coord_x = coordinates_x[i].regamma_y_green;
                else
                        coord_x = coordinates_x[i].regamma_y_blue;

                if (!find_software_points(
                        ramp, axis_x, coord_x, channel,
                        &index_to_start, &index_left, &index_right, &hw_pos)) {
                        BREAK_TO_DEBUGGER();
                        return false;
                }

                if (index_left >= ramp->num_entries + 3) {
                        BREAK_TO_DEBUGGER();
                        return false;
                }

                if (index_right >= ramp->num_entries + 3) {
                        BREAK_TO_DEBUGGER();
                        return false;
                }

                if (channel == CHANNEL_NAME_RED) {
                        point = &coeff[i].r;

                        left_pos = axis_x[index_left].r;
                        right_pos = axis_x[index_right].r;
                } else if (channel == CHANNEL_NAME_GREEN) {
                        point = &coeff[i].g;

                        left_pos = axis_x[index_left].g;
                        right_pos = axis_x[index_right].g;
                } else {
                        point = &coeff[i].b;

                        left_pos = axis_x[index_left].b;
                        right_pos = axis_x[index_right].b;
                }

                if (hw_pos == HW_POINT_POSITION_MIDDLE)
                        point->coeff = dc_fixpt_div(
                                dc_fixpt_sub(
                                        coord_x,
                                        left_pos),
                                dc_fixpt_sub(
                                        right_pos,
                                        left_pos));
                else if (hw_pos == HW_POINT_POSITION_LEFT)
                        point->coeff = dc_fixpt_zero;
                else if (hw_pos == HW_POINT_POSITION_RIGHT)
                        point->coeff = dc_fixpt_from_int(2);
                else {
                        BREAK_TO_DEBUGGER();
                        return false;
                }

                point->left_index = index_left;
                point->right_index = index_right;
                point->pos = hw_pos;

                ++i;
        }

        return true;
}

static struct fixed31_32 calculate_mapped_value(
        struct pwl_float_data *rgb,
        const struct pixel_gamma_point *coeff,
        enum channel_name channel,
        uint32_t max_index)
{
        const struct gamma_point *point;

        struct fixed31_32 result;

        if (channel == CHANNEL_NAME_RED)
                point = &coeff->r;
        else if (channel == CHANNEL_NAME_GREEN)
                point = &coeff->g;
        else
                point = &coeff->b;

        if ((point->left_index < 0) || (point->left_index > max_index)) {
                BREAK_TO_DEBUGGER();
                return dc_fixpt_zero;
        }

        if ((point->right_index < 0) || (point->right_index > max_index)) {
                BREAK_TO_DEBUGGER();
                return dc_fixpt_zero;
        }

        if (point->pos == HW_POINT_POSITION_MIDDLE)
                if (channel == CHANNEL_NAME_RED)
                        result = dc_fixpt_add(
                                dc_fixpt_mul(
                                        point->coeff,
                                        dc_fixpt_sub(
                                                rgb[point->right_index].r,
                                                rgb[point->left_index].r)),
                                rgb[point->left_index].r);
                else if (channel == CHANNEL_NAME_GREEN)
                        result = dc_fixpt_add(
                                dc_fixpt_mul(
                                        point->coeff,
                                        dc_fixpt_sub(
                                                rgb[point->right_index].g,
                                                rgb[point->left_index].g)),
                                rgb[point->left_index].g);
                else
                        result = dc_fixpt_add(
                                dc_fixpt_mul(
                                        point->coeff,
                                        dc_fixpt_sub(
                                                rgb[point->right_index].b,
                                                rgb[point->left_index].b)),
                                rgb[point->left_index].b);
        else if (point->pos == HW_POINT_POSITION_LEFT) {
                BREAK_TO_DEBUGGER();
                result = dc_fixpt_zero;
        } else {
                BREAK_TO_DEBUGGER();
                result = dc_fixpt_one;
        }

        return result;
}

static void build_pq(struct pwl_float_data_ex *rgb_regamma,
                uint32_t hw_points_num,
                const struct hw_x_point *coordinate_x,
                uint32_t sdr_white_level)
{
        uint32_t i, start_index;

        struct pwl_float_data_ex *rgb = rgb_regamma;
        const struct hw_x_point *coord_x = coordinate_x;
        struct fixed31_32 x;
        struct fixed31_32 output;
        struct fixed31_32 scaling_factor =
                        dc_fixpt_from_fraction(sdr_white_level, 10000);

        if (!pq_initialized && sdr_white_level == 80) {
                precompute_pq();
                pq_initialized = true;
        }

        /* TODO: start index is from segment 2^-24, skipping first segment
         * due to x values too small for power calculations
         */
        start_index = 32;
        rgb += start_index;
        coord_x += start_index;

        for (i = start_index; i <= hw_points_num; i++) {
                /* Multiply 0.008 as regamma is 0-1 and FP16 input is 0-125.
                 * FP 1.0 = 80nits
                 */
                if (sdr_white_level == 80) {
                        output = pq_table[i];
                } else {
                        x = dc_fixpt_mul(coord_x->x, scaling_factor);
                        compute_pq(x, &output);
                }

                /* should really not happen? */
                if (dc_fixpt_lt(output, dc_fixpt_zero))
                        output = dc_fixpt_zero;
                else if (dc_fixpt_lt(dc_fixpt_one, output))
                        output = dc_fixpt_one;

                rgb->r = output;
                rgb->g = output;
                rgb->b = output;

                ++coord_x;
                ++rgb;
        }
}

static void build_de_pq(struct pwl_float_data_ex *de_pq,
                uint32_t hw_points_num,
                const struct hw_x_point *coordinate_x)
{
        uint32_t i;
        struct fixed31_32 output;

        struct fixed31_32 scaling_factor = dc_fixpt_from_int(125);

        if (!de_pq_initialized) {
                precompute_de_pq();
                de_pq_initialized = true;
        }


        for (i = 0; i <= hw_points_num; i++) {
                output = de_pq_table[i];
                /* should really not happen? */
                if (dc_fixpt_lt(output, dc_fixpt_zero))
                        output = dc_fixpt_zero;
                else if (dc_fixpt_lt(scaling_factor, output))
                        output = scaling_factor;
                de_pq[i].r = output;
                de_pq[i].g = output;
                de_pq[i].b = output;
        }
}

static void build_regamma(struct pwl_float_data_ex *rgb_regamma,
                uint32_t hw_points_num,
                const struct hw_x_point *coordinate_x, enum gamma_type_index type)
{
        uint32_t i;

        struct gamma_coefficients coeff;
        struct pwl_float_data_ex *rgb = rgb_regamma;
        const struct hw_x_point *coord_x = coordinate_x;

        build_coefficients(&coeff, type);

        i = 0;

        while (i != hw_points_num + 1) {
                /*TODO use y vs r,g,b*/
                rgb->r = translate_from_linear_space_ex(
                        coord_x->x, &coeff, 0);
                rgb->g = rgb->r;
                rgb->b = rgb->r;
                ++coord_x;
                ++rgb;
                ++i;
        }
}

static void hermite_spline_eetf(struct fixed31_32 input_x,
                                struct fixed31_32 max_display,
                                struct fixed31_32 min_display,
                                struct fixed31_32 max_content,
                                struct fixed31_32 *out_x)
{
        struct fixed31_32 min_lum_pq;
        struct fixed31_32 max_lum_pq;
        struct fixed31_32 max_content_pq;
        struct fixed31_32 ks;
        struct fixed31_32 E1;
        struct fixed31_32 E2;
        struct fixed31_32 E3;
        struct fixed31_32 t;
        struct fixed31_32 t2;
        struct fixed31_32 t3;
        struct fixed31_32 two;
        struct fixed31_32 three;
        struct fixed31_32 temp1;
        struct fixed31_32 temp2;
        struct fixed31_32 a = dc_fixpt_from_fraction(15, 10);
        struct fixed31_32 b = dc_fixpt_from_fraction(5, 10);
        struct fixed31_32 epsilon = dc_fixpt_from_fraction(1, 1000000); // dc_fixpt_epsilon is a bit too small

        if (dc_fixpt_eq(max_content, dc_fixpt_zero)) {
                *out_x = dc_fixpt_zero;
                return;
        }

        compute_pq(input_x, &E1);
        compute_pq(dc_fixpt_div(min_display, max_content), &min_lum_pq);
        compute_pq(dc_fixpt_div(max_display, max_content), &max_lum_pq);
        compute_pq(dc_fixpt_one, &max_content_pq); // always 1? DAL2 code is weird
        a = dc_fixpt_div(dc_fixpt_add(dc_fixpt_one, b), max_content_pq); // (1+b)/maxContent
        ks = dc_fixpt_sub(dc_fixpt_mul(a, max_lum_pq), b); // a * max_lum_pq - b

        if (dc_fixpt_lt(E1, ks))
                E2 = E1;
        else if (dc_fixpt_le(ks, E1) && dc_fixpt_le(E1, dc_fixpt_one)) {
                if (dc_fixpt_lt(epsilon, dc_fixpt_sub(dc_fixpt_one, ks)))
                        // t = (E1 - ks) / (1 - ks)
                        t = dc_fixpt_div(dc_fixpt_sub(E1, ks),
                                        dc_fixpt_sub(dc_fixpt_one, ks));
                else
                        t = dc_fixpt_zero;

                two = dc_fixpt_from_int(2);
                three = dc_fixpt_from_int(3);

                t2 = dc_fixpt_mul(t, t);
                t3 = dc_fixpt_mul(t2, t);
                temp1 = dc_fixpt_mul(two, t3);
                temp2 = dc_fixpt_mul(three, t2);

                // (2t^3 - 3t^2 + 1) * ks
                E2 = dc_fixpt_mul(ks, dc_fixpt_add(dc_fixpt_one,
                                dc_fixpt_sub(temp1, temp2)));

                // (-2t^3 + 3t^2) * max_lum_pq
                E2 = dc_fixpt_add(E2, dc_fixpt_mul(max_lum_pq,
                                dc_fixpt_sub(temp2, temp1)));

                temp1 = dc_fixpt_mul(two, t2);
                temp2 = dc_fixpt_sub(dc_fixpt_one, ks);

                // (t^3 - 2t^2 + t) * (1-ks)
                E2 = dc_fixpt_add(E2, dc_fixpt_mul(temp2,
                                dc_fixpt_add(t, dc_fixpt_sub(t3, temp1))));
        } else
                E2 = dc_fixpt_one;

        temp1 = dc_fixpt_sub(dc_fixpt_one, E2);
        temp2 = dc_fixpt_mul(temp1, temp1);
        temp2 = dc_fixpt_mul(temp2, temp2);
        // temp2 = (1-E2)^4

        E3 =  dc_fixpt_add(E2, dc_fixpt_mul(min_lum_pq, temp2));
        compute_de_pq(E3, out_x);

        *out_x = dc_fixpt_div(*out_x, dc_fixpt_div(max_display, max_content));
}

static bool build_freesync_hdr(struct pwl_float_data_ex *rgb_regamma,
                uint32_t hw_points_num,
                const struct hw_x_point *coordinate_x,
                const struct freesync_hdr_tf_params *fs_params)
{
        uint32_t i;
        struct pwl_float_data_ex *rgb = rgb_regamma;
        const struct hw_x_point *coord_x = coordinate_x;
        struct fixed31_32 scaledX = dc_fixpt_zero;
        struct fixed31_32 scaledX1 = dc_fixpt_zero;
        struct fixed31_32 max_display;
        struct fixed31_32 min_display;
        struct fixed31_32 max_content;
        struct fixed31_32 min_content;
        struct fixed31_32 clip = dc_fixpt_one;
        struct fixed31_32 output;
        bool use_eetf = false;
        bool is_clipped = false;
        struct fixed31_32 sdr_white_level;

        if (fs_params->max_content == 0 ||
                        fs_params->max_display == 0)
                return false;

        max_display = dc_fixpt_from_int(fs_params->max_display);
        min_display = dc_fixpt_from_fraction(fs_params->min_display, 10000);
        max_content = dc_fixpt_from_int(fs_params->max_content);
        min_content = dc_fixpt_from_fraction(fs_params->min_content, 10000);
        sdr_white_level = dc_fixpt_from_int(fs_params->sdr_white_level);

        if (fs_params->min_display > 1000) // cap at 0.1 at the bottom
                min_display = dc_fixpt_from_fraction(1, 10);
        if (fs_params->max_display < 100) // cap at 100 at the top
                max_display = dc_fixpt_from_int(100);

        if (fs_params->min_content < fs_params->min_display)
                use_eetf = true;
        else
                min_content = min_display;

        if (fs_params->max_content > fs_params->max_display)
                use_eetf = true;
        else
                max_content = max_display;

        rgb += 32; // first 32 points have problems with fixed point, too small
        coord_x += 32;
        for (i = 32; i <= hw_points_num; i++) {
                if (!is_clipped) {
                        if (use_eetf) {
                                /*max content is equal 1 */
                                scaledX1 = dc_fixpt_div(coord_x->x,
                                                dc_fixpt_div(max_content, sdr_white_level));
                                hermite_spline_eetf(scaledX1, max_display, min_display,
                                                max_content, &scaledX);
                        } else
                                scaledX = dc_fixpt_div(coord_x->x,
                                                dc_fixpt_div(max_display, sdr_white_level));

                        if (dc_fixpt_lt(scaledX, clip)) {
                                if (dc_fixpt_lt(scaledX, dc_fixpt_zero))
                                        output = dc_fixpt_zero;
                                else
                                        output = calculate_gamma22(scaledX);

                                rgb->r = output;
                                rgb->g = output;
                                rgb->b = output;
                        } else {
                                is_clipped = true;
                                rgb->r = clip;
                                rgb->g = clip;
                                rgb->b = clip;
                        }
                } else {
                        rgb->r = clip;
                        rgb->g = clip;
                        rgb->b = clip;
                }

                ++coord_x;
                ++rgb;
        }

        return true;
}

static void build_degamma(struct pwl_float_data_ex *curve,
                uint32_t hw_points_num,
                const struct hw_x_point *coordinate_x, enum gamma_type_index type)
{
        uint32_t i;
        struct gamma_coefficients coeff;
        uint32_t begin_index, end_index;

        build_coefficients(&coeff, type);
        i = 0;

        /* X points is 2^-25 to 2^7
         * De-gamma X is 2^-12 to 2^0 – we are skipping first -12-(-25) = 13 regions
         */
        begin_index = 13 * NUM_PTS_IN_REGION;
        end_index = begin_index + 12 * NUM_PTS_IN_REGION;

        while (i != begin_index) {
                curve[i].r = dc_fixpt_zero;
                curve[i].g = dc_fixpt_zero;
                curve[i].b = dc_fixpt_zero;
                i++;
        }

        while (i != end_index) {
                curve[i].r = translate_to_linear_space_ex(
                                coordinate_x[i].x, &coeff, 0);
                curve[i].g = curve[i].r;
                curve[i].b = curve[i].r;
                i++;
        }
        while (i != hw_points_num + 1) {
                curve[i].r = dc_fixpt_one;
                curve[i].g = dc_fixpt_one;
                curve[i].b = dc_fixpt_one;
                i++;
        }
}

static void build_hlg_degamma(struct pwl_float_data_ex *degamma,
                uint32_t hw_points_num,
                const struct hw_x_point *coordinate_x, bool is_light0_12)
{
        uint32_t i;

        struct pwl_float_data_ex *rgb = degamma;
        const struct hw_x_point *coord_x = coordinate_x;

        i = 0;

        while (i != hw_points_num + 1) {
                compute_hlg_oetf(coord_x->x, is_light0_12, &rgb->r);
                rgb->g = rgb->r;
                rgb->b = rgb->r;
                ++coord_x;
                ++rgb;
                ++i;
        }
}

static void build_hlg_regamma(struct pwl_float_data_ex *regamma,
                uint32_t hw_points_num,
                const struct hw_x_point *coordinate_x, bool is_light0_12)
{
        uint32_t i;

        struct pwl_float_data_ex *rgb = regamma;
        const struct hw_x_point *coord_x = coordinate_x;

        i = 0;

        while (i != hw_points_num + 1) {
                compute_hlg_eotf(coord_x->x, is_light0_12, &rgb->r);
                rgb->g = rgb->r;
                rgb->b = rgb->r;
                ++coord_x;
                ++rgb;
                ++i;
        }
}

static void scale_gamma(struct pwl_float_data *pwl_rgb,
                const struct dc_gamma *ramp,
                struct dividers dividers)
{
        const struct fixed31_32 max_driver = dc_fixpt_from_int(0xFFFF);
        const struct fixed31_32 max_os = dc_fixpt_from_int(0xFF00);
        struct fixed31_32 scaler = max_os;
        uint32_t i;
        struct pwl_float_data *rgb = pwl_rgb;
        struct pwl_float_data *rgb_last = rgb + ramp->num_entries - 1;

        i = 0;

        do {
                if (dc_fixpt_lt(max_os, ramp->entries.red[i]) ||
                        dc_fixpt_lt(max_os, ramp->entries.green[i]) ||
                        dc_fixpt_lt(max_os, ramp->entries.blue[i])) {
                        scaler = max_driver;
                        break;
                }
                ++i;
        } while (i != ramp->num_entries);

        i = 0;

        do {
                rgb->r = dc_fixpt_div(
                        ramp->entries.red[i], scaler);
                rgb->g = dc_fixpt_div(
                        ramp->entries.green[i], scaler);
                rgb->b = dc_fixpt_div(
                        ramp->entries.blue[i], scaler);

                ++rgb;
                ++i;
        } while (i != ramp->num_entries);

        rgb->r = dc_fixpt_mul(rgb_last->r,
                        dividers.divider1);
        rgb->g = dc_fixpt_mul(rgb_last->g,
                        dividers.divider1);
        rgb->b = dc_fixpt_mul(rgb_last->b,
                        dividers.divider1);

        ++rgb;

        rgb->r = dc_fixpt_mul(rgb_last->r,
                        dividers.divider2);
        rgb->g = dc_fixpt_mul(rgb_last->g,
                        dividers.divider2);
        rgb->b = dc_fixpt_mul(rgb_last->b,
                        dividers.divider2);

        ++rgb;

        rgb->r = dc_fixpt_mul(rgb_last->r,
                        dividers.divider3);
        rgb->g = dc_fixpt_mul(rgb_last->g,
                        dividers.divider3);
        rgb->b = dc_fixpt_mul(rgb_last->b,
                        dividers.divider3);
}

static void scale_gamma_dx(struct pwl_float_data *pwl_rgb,
                const struct dc_gamma *ramp,
                struct dividers dividers)
{
        uint32_t i;
        struct fixed31_32 min = dc_fixpt_zero;
        struct fixed31_32 max = dc_fixpt_one;

        struct fixed31_32 delta = dc_fixpt_zero;
        struct fixed31_32 offset = dc_fixpt_zero;

        for (i = 0 ; i < ramp->num_entries; i++) {
                if (dc_fixpt_lt(ramp->entries.red[i], min))
                        min = ramp->entries.red[i];

                if (dc_fixpt_lt(ramp->entries.green[i], min))
                        min = ramp->entries.green[i];

                if (dc_fixpt_lt(ramp->entries.blue[i], min))
                        min = ramp->entries.blue[i];

                if (dc_fixpt_lt(max, ramp->entries.red[i]))
                        max = ramp->entries.red[i];

                if (dc_fixpt_lt(max, ramp->entries.green[i]))
                        max = ramp->entries.green[i];

                if (dc_fixpt_lt(max, ramp->entries.blue[i]))
                        max = ramp->entries.blue[i];
        }

        if (dc_fixpt_lt(min, dc_fixpt_zero))
                delta = dc_fixpt_neg(min);

        offset = dc_fixpt_add(min, max);

        for (i = 0 ; i < ramp->num_entries; i++) {
                pwl_rgb[i].r = dc_fixpt_div(
                        dc_fixpt_add(
                                ramp->entries.red[i], delta), offset);
                pwl_rgb[i].g = dc_fixpt_div(
                        dc_fixpt_add(
                                ramp->entries.green[i], delta), offset);
                pwl_rgb[i].b = dc_fixpt_div(
                        dc_fixpt_add(
                                ramp->entries.blue[i], delta), offset);

        }

        pwl_rgb[i].r =  dc_fixpt_sub(dc_fixpt_mul_int(
                                pwl_rgb[i-1].r, 2), pwl_rgb[i-2].r);
        pwl_rgb[i].g =  dc_fixpt_sub(dc_fixpt_mul_int(
                                pwl_rgb[i-1].g, 2), pwl_rgb[i-2].g);
        pwl_rgb[i].b =  dc_fixpt_sub(dc_fixpt_mul_int(
                                pwl_rgb[i-1].b, 2), pwl_rgb[i-2].b);
        ++i;
        pwl_rgb[i].r =  dc_fixpt_sub(dc_fixpt_mul_int(
                                pwl_rgb[i-1].r, 2), pwl_rgb[i-2].r);
        pwl_rgb[i].g =  dc_fixpt_sub(dc_fixpt_mul_int(
                                pwl_rgb[i-1].g, 2), pwl_rgb[i-2].g);
        pwl_rgb[i].b =  dc_fixpt_sub(dc_fixpt_mul_int(
                                pwl_rgb[i-1].b, 2), pwl_rgb[i-2].b);
}

/* todo: all these scale_gamma functions are inherently the same but
 *  take different structures as params or different format for ramp
 *  values. We could probably implement it in a more generic fashion
 */
static void scale_user_regamma_ramp(struct pwl_float_data *pwl_rgb,
                const struct regamma_ramp *ramp,
                struct dividers dividers)
{
        unsigned short max_driver = 0xFFFF;
        unsigned short max_os = 0xFF00;
        unsigned short scaler = max_os;
        uint32_t i;
        struct pwl_float_data *rgb = pwl_rgb;
        struct pwl_float_data *rgb_last = rgb + GAMMA_RGB_256_ENTRIES - 1;

        i = 0;
        do {
                if (ramp->gamma[i] > max_os ||
                                ramp->gamma[i + 256] > max_os ||
                                ramp->gamma[i + 512] > max_os) {
                        scaler = max_driver;
                        break;
                }
                i++;
        } while (i != GAMMA_RGB_256_ENTRIES);

        i = 0;
        do {
                rgb->r = dc_fixpt_from_fraction(
                                ramp->gamma[i], scaler);
                rgb->g = dc_fixpt_from_fraction(
                                ramp->gamma[i + 256], scaler);
                rgb->b = dc_fixpt_from_fraction(
                                ramp->gamma[i + 512], scaler);

                ++rgb;
                ++i;
        } while (i != GAMMA_RGB_256_ENTRIES);

        rgb->r = dc_fixpt_mul(rgb_last->r,
                        dividers.divider1);
        rgb->g = dc_fixpt_mul(rgb_last->g,
                        dividers.divider1);
        rgb->b = dc_fixpt_mul(rgb_last->b,
                        dividers.divider1);

        ++rgb;

        rgb->r = dc_fixpt_mul(rgb_last->r,
                        dividers.divider2);
        rgb->g = dc_fixpt_mul(rgb_last->g,
                        dividers.divider2);
        rgb->b = dc_fixpt_mul(rgb_last->b,
                        dividers.divider2);

        ++rgb;

        rgb->r = dc_fixpt_mul(rgb_last->r,
                        dividers.divider3);
        rgb->g = dc_fixpt_mul(rgb_last->g,
                        dividers.divider3);
        rgb->b = dc_fixpt_mul(rgb_last->b,
                        dividers.divider3);
}

/*
 * RS3+ color transform DDI - 1D LUT adjustment is composed with regamma here
 * Input is evenly distributed in the output color space as specified in
 * SetTimings
 *
 * Interpolation details:
 * 1D LUT has 4096 values which give curve correction in 0-1 float range
 * for evenly spaced points in 0-1 range. lut1D[index] gives correction
 * for index/4095.
 * First we find index for which:
 *      index/4095 < regamma_y < (index+1)/4095 =>
 *      index < 4095*regamma_y < index + 1
 * norm_y = 4095*regamma_y, and index is just truncating to nearest integer
 * lut1 = lut1D[index], lut2 = lut1D[index+1]
 *
 * adjustedY is then linearly interpolating regamma Y between lut1 and lut2
 *
 * Custom degamma on Linux uses the same interpolation math, so is handled here
 */
static void apply_lut_1d(
                const struct dc_gamma *ramp,
                uint32_t num_hw_points,
                struct dc_transfer_func_distributed_points *tf_pts)
{
        int i = 0;
        int color = 0;
        struct fixed31_32 *regamma_y;
        struct fixed31_32 norm_y;
        struct fixed31_32 lut1;
        struct fixed31_32 lut2;
        const int max_lut_index = 4095;
        const struct fixed31_32 max_lut_index_f =
                        dc_fixpt_from_int(max_lut_index);
        int32_t index = 0, index_next = 0;
        struct fixed31_32 index_f;
        struct fixed31_32 delta_lut;
        struct fixed31_32 delta_index;

        if (ramp->type != GAMMA_CS_TFM_1D && ramp->type != GAMMA_CUSTOM)
                return; // this is not expected

        for (i = 0; i < num_hw_points; i++) {
                for (color = 0; color < 3; color++) {
                        if (color == 0)
                                regamma_y = &tf_pts->red[i];
                        else if (color == 1)
                                regamma_y = &tf_pts->green[i];
                        else
                                regamma_y = &tf_pts->blue[i];

                        norm_y = dc_fixpt_mul(max_lut_index_f,
                                                   *regamma_y);
                        index = dc_fixpt_floor(norm_y);
                        index_f = dc_fixpt_from_int(index);

                        if (index < 0 || index > max_lut_index)
                                continue;

                        index_next = (index == max_lut_index) ? index : index+1;

                        if (color == 0) {
                                lut1 = ramp->entries.red[index];
                                lut2 = ramp->entries.red[index_next];
                        } else if (color == 1) {
                                lut1 = ramp->entries.green[index];
                                lut2 = ramp->entries.green[index_next];
                        } else {
                                lut1 = ramp->entries.blue[index];
                                lut2 = ramp->entries.blue[index_next];
                        }

                        // we have everything now, so interpolate
                        delta_lut = dc_fixpt_sub(lut2, lut1);
                        delta_index = dc_fixpt_sub(norm_y, index_f);

                        *regamma_y = dc_fixpt_add(lut1,
                                dc_fixpt_mul(delta_index, delta_lut));
                }
        }
}

static void build_evenly_distributed_points(
        struct gamma_pixel *points,
        uint32_t numberof_points,
        struct dividers dividers)
{
        struct gamma_pixel *p = points;
        struct gamma_pixel *p_last;

        uint32_t i = 0;

        // This function should not gets called with 0 as a parameter
        ASSERT(numberof_points > 0);
        p_last = p + numberof_points - 1;

        do {
                struct fixed31_32 value = dc_fixpt_from_fraction(i,
                        numberof_points - 1);

                p->r = value;
                p->g = value;
                p->b = value;

                ++p;
                ++i;
        } while (i < numberof_points);

        p->r = dc_fixpt_div(p_last->r, dividers.divider1);
        p->g = dc_fixpt_div(p_last->g, dividers.divider1);
        p->b = dc_fixpt_div(p_last->b, dividers.divider1);

        ++p;

        p->r = dc_fixpt_div(p_last->r, dividers.divider2);
        p->g = dc_fixpt_div(p_last->g, dividers.divider2);
        p->b = dc_fixpt_div(p_last->b, dividers.divider2);

        ++p;

        p->r = dc_fixpt_div(p_last->r, dividers.divider3);
        p->g = dc_fixpt_div(p_last->g, dividers.divider3);
        p->b = dc_fixpt_div(p_last->b, dividers.divider3);
}

static inline void copy_rgb_regamma_to_coordinates_x(
                struct hw_x_point *coordinates_x,
                uint32_t hw_points_num,
                const struct pwl_float_data_ex *rgb_ex)
{
        struct hw_x_point *coords = coordinates_x;
        uint32_t i = 0;
        const struct pwl_float_data_ex *rgb_regamma = rgb_ex;

        while (i <= hw_points_num + 1) {
                coords->regamma_y_red = rgb_regamma->r;
                coords->regamma_y_green = rgb_regamma->g;
                coords->regamma_y_blue = rgb_regamma->b;

                ++coords;
                ++rgb_regamma;
                ++i;
        }
}

static bool calculate_interpolated_hardware_curve(
        const struct dc_gamma *ramp,
        struct pixel_gamma_point *coeff128,
        struct pwl_float_data *rgb_user,
        const struct hw_x_point *coordinates_x,
        const struct gamma_pixel *axis_x,
        uint32_t number_of_points,
        struct dc_transfer_func_distributed_points *tf_pts)
{

        const struct pixel_gamma_point *coeff = coeff128;
        uint32_t max_entries = 3 - 1;

        uint32_t i = 0;

        for (i = 0; i < 3; i++) {
                if (!build_custom_gamma_mapping_coefficients_worker(
                                ramp, coeff128, coordinates_x, axis_x, i,
                                number_of_points))
                        return false;
        }

        i = 0;
        max_entries += ramp->num_entries;

        /* TODO: float point case */

        while (i <= number_of_points) {
                tf_pts->red[i] = calculate_mapped_value(
                        rgb_user, coeff, CHANNEL_NAME_RED, max_entries);
                tf_pts->green[i] = calculate_mapped_value(
                        rgb_user, coeff, CHANNEL_NAME_GREEN, max_entries);
                tf_pts->blue[i] = calculate_mapped_value(
                        rgb_user, coeff, CHANNEL_NAME_BLUE, max_entries);

                ++coeff;
                ++i;
        }

        return true;
}

/* The "old" interpolation uses a complicated scheme to build an array of
 * coefficients while also using an array of 0-255 normalized to 0-1
 * Then there's another loop using both of the above + new scaled user ramp
 * and we concatenate them. It also searches for points of interpolation and
 * uses enums for positions.
 *
 * This function uses a different approach:
 * user ramp is always applied on X with 0/255, 1/255, 2/255, ..., 255/255
 * To find index for hwX , we notice the following:
 * i/255 <= hwX < (i+1)/255  <=> i <= 255*hwX < i+1
 * See apply_lut_1d which is the same principle, but on 4K entry 1D LUT
 *
 * Once the index is known, combined Y is simply:
 * user_ramp(index) + (hwX-index/255)*(user_ramp(index+1) - user_ramp(index)
 *
 * We should switch to this method in all cases, it's simpler and faster
 * ToDo one day - for now this only applies to ADL regamma to avoid regression
 * for regular use cases (sRGB and PQ)
 */
static void interpolate_user_regamma(uint32_t hw_points_num,
                struct pwl_float_data *rgb_user,
                bool apply_degamma,
                struct dc_transfer_func_distributed_points *tf_pts)
{
        uint32_t i;
        uint32_t color = 0;
        int32_t index;
        int32_t index_next;
        struct fixed31_32 *tf_point;
        struct fixed31_32 hw_x;
        struct fixed31_32 norm_factor =
                        dc_fixpt_from_int(255);
        struct fixed31_32 norm_x;
        struct fixed31_32 index_f;
        struct fixed31_32 lut1;
        struct fixed31_32 lut2;
        struct fixed31_32 delta_lut;
        struct fixed31_32 delta_index;

        i = 0;
        /* fixed_pt library has problems handling too small values */
        while (i != 32) {
                tf_pts->red[i] = dc_fixpt_zero;
                tf_pts->green[i] = dc_fixpt_zero;
                tf_pts->blue[i] = dc_fixpt_zero;
                ++i;
        }
        while (i <= hw_points_num + 1) {
                for (color = 0; color < 3; color++) {
                        if (color == 0)
                                tf_point = &tf_pts->red[i];
                        else if (color == 1)
                                tf_point = &tf_pts->green[i];
                        else
                                tf_point = &tf_pts->blue[i];

                        if (apply_degamma) {
                                if (color == 0)
                                        hw_x = coordinates_x[i].regamma_y_red;
                                else if (color == 1)
                                        hw_x = coordinates_x[i].regamma_y_green;
                                else
                                        hw_x = coordinates_x[i].regamma_y_blue;
                        } else
                                hw_x = coordinates_x[i].x;

                        norm_x = dc_fixpt_mul(norm_factor, hw_x);
                        index = dc_fixpt_floor(norm_x);
                        if (index < 0 || index > 255)
                                continue;

                        index_f = dc_fixpt_from_int(index);
                        index_next = (index == 255) ? index : index + 1;

                        if (color == 0) {
                                lut1 = rgb_user[index].r;
                                lut2 = rgb_user[index_next].r;
                        } else if (color == 1) {
                                lut1 = rgb_user[index].g;
                                lut2 = rgb_user[index_next].g;
                        } else {
                                lut1 = rgb_user[index].b;
                                lut2 = rgb_user[index_next].b;
                        }

                        // we have everything now, so interpolate
                        delta_lut = dc_fixpt_sub(lut2, lut1);
                        delta_index = dc_fixpt_sub(norm_x, index_f);

                        *tf_point = dc_fixpt_add(lut1,
                                dc_fixpt_mul(delta_index, delta_lut));
                }
                ++i;
        }
}

static void build_new_custom_resulted_curve(
        uint32_t hw_points_num,
        struct dc_transfer_func_distributed_points *tf_pts)
{
        uint32_t i;

        i = 0;

        while (i != hw_points_num + 1) {
                tf_pts->red[i] = dc_fixpt_clamp(
                        tf_pts->red[i], dc_fixpt_zero,
                        dc_fixpt_one);
                tf_pts->green[i] = dc_fixpt_clamp(
                        tf_pts->green[i], dc_fixpt_zero,
                        dc_fixpt_one);
                tf_pts->blue[i] = dc_fixpt_clamp(
                        tf_pts->blue[i], dc_fixpt_zero,
                        dc_fixpt_one);

                ++i;
        }
}

static void apply_degamma_for_user_regamma(struct pwl_float_data_ex *rgb_regamma,
                uint32_t hw_points_num)
{
        uint32_t i;

        struct gamma_coefficients coeff;
        struct pwl_float_data_ex *rgb = rgb_regamma;
        const struct hw_x_point *coord_x = coordinates_x;

        build_coefficients(&coeff, true);

        i = 0;
        while (i != hw_points_num + 1) {
                rgb->r = translate_from_linear_space_ex(
                                coord_x->x, &coeff, 0);
                rgb->g = rgb->r;
                rgb->b = rgb->r;
                ++coord_x;
                ++rgb;
                ++i;
        }
}

static bool map_regamma_hw_to_x_user(
        const struct dc_gamma *ramp,
        struct pixel_gamma_point *coeff128,
        struct pwl_float_data *rgb_user,
        struct hw_x_point *coords_x,
        const struct gamma_pixel *axis_x,
        const struct pwl_float_data_ex *rgb_regamma,
        uint32_t hw_points_num,
        struct dc_transfer_func_distributed_points *tf_pts,
        bool mapUserRamp)
{
        /* setup to spare calculated ideal regamma values */

        int i = 0;
        struct hw_x_point *coords = coords_x;
        const struct pwl_float_data_ex *regamma = rgb_regamma;

        if (ramp && mapUserRamp) {
                copy_rgb_regamma_to_coordinates_x(coords,
                                hw_points_num,
                                rgb_regamma);

                calculate_interpolated_hardware_curve(
                        ramp, coeff128, rgb_user, coords, axis_x,
                        hw_points_num, tf_pts);
        } else {
                /* just copy current rgb_regamma into  tf_pts */
                while (i <= hw_points_num) {
                        tf_pts->red[i] = regamma->r;
                        tf_pts->green[i] = regamma->g;
                        tf_pts->blue[i] = regamma->b;

                        ++regamma;
                        ++i;
                }
        }

        /* this should be named differently, all it does is clamp to 0-1 */
        build_new_custom_resulted_curve(hw_points_num, tf_pts);

        return true;
}

#define _EXTRA_POINTS 3

bool mod_color_calculate_regamma_params(struct dc_transfer_func *output_tf,
                const struct dc_gamma *ramp, bool mapUserRamp, bool canRomBeUsed,
                const struct freesync_hdr_tf_params *fs_params)
{
        struct dc_transfer_func_distributed_points *tf_pts = &output_tf->tf_pts;
        struct dividers dividers;

        struct pwl_float_data *rgb_user = NULL;
        struct pwl_float_data_ex *rgb_regamma = NULL;
        struct gamma_pixel *axis_x = NULL;
        struct pixel_gamma_point *coeff = NULL;
        enum dc_transfer_func_predefined tf = TRANSFER_FUNCTION_SRGB;
        bool ret = false;

        if (output_tf->type == TF_TYPE_BYPASS)
                return false;

        /* we can use hardcoded curve for plain SRGB TF */
        if (output_tf->type == TF_TYPE_PREDEFINED && canRomBeUsed == true &&
                        output_tf->tf == TRANSFER_FUNCTION_SRGB) {
                if (ramp == NULL)
                        return true;
                if ((ramp->is_logical_identity) ||
                                (!mapUserRamp && ramp->type == GAMMA_RGB_256))
                        return true;
        }

        output_tf->type = TF_TYPE_DISTRIBUTED_POINTS;

        if (ramp && (mapUserRamp || ramp->type != GAMMA_RGB_256)) {
                rgb_user = kvcalloc(ramp->num_entries + _EXTRA_POINTS,
                            sizeof(*rgb_user),
                            GFP_KERNEL);
                if (!rgb_user)
                        goto rgb_user_alloc_fail;

                axis_x = kvcalloc(ramp->num_entries + 3, sizeof(*axis_x),
                                GFP_KERNEL);
                if (!axis_x)
                        goto axis_x_alloc_fail;

                dividers.divider1 = dc_fixpt_from_fraction(3, 2);
                dividers.divider2 = dc_fixpt_from_int(2);
                dividers.divider3 = dc_fixpt_from_fraction(5, 2);

                build_evenly_distributed_points(
                                axis_x,
                                ramp->num_entries,
                                dividers);

                if (ramp->type == GAMMA_RGB_256 && mapUserRamp)
                        scale_gamma(rgb_user, ramp, dividers);
                else if (ramp->type == GAMMA_RGB_FLOAT_1024)
                        scale_gamma_dx(rgb_user, ramp, dividers);
        }

        rgb_regamma = kvcalloc(MAX_HW_POINTS + _EXTRA_POINTS,
                               sizeof(*rgb_regamma),
                               GFP_KERNEL);
        if (!rgb_regamma)
                goto rgb_regamma_alloc_fail;

        coeff = kvcalloc(MAX_HW_POINTS + _EXTRA_POINTS, sizeof(*coeff),
                         GFP_KERNEL);
        if (!coeff)
                goto coeff_alloc_fail;

        tf = output_tf->tf;
        if (tf == TRANSFER_FUNCTION_PQ) {
                tf_pts->end_exponent = 7;
                tf_pts->x_point_at_y1_red = 125;
                tf_pts->x_point_at_y1_green = 125;
                tf_pts->x_point_at_y1_blue = 125;

                build_pq(rgb_regamma,
                                MAX_HW_POINTS,
                                coordinates_x,
                                output_tf->sdr_ref_white_level);
        } else if (tf == TRANSFER_FUNCTION_GAMMA22 &&
                        fs_params != NULL && fs_params->skip_tm == 0) {
                build_freesync_hdr(rgb_regamma,
                                MAX_HW_POINTS,
                                coordinates_x,
                                fs_params);
        } else {
                tf_pts->end_exponent = 0;
                tf_pts->x_point_at_y1_red = 1;
                tf_pts->x_point_at_y1_green = 1;
                tf_pts->x_point_at_y1_blue = 1;

                build_regamma(rgb_regamma,
                                MAX_HW_POINTS,
                                coordinates_x, tf == TRANSFER_FUNCTION_SRGB ? gamma_type_index_2_4 :
                                        tf == TRANSFER_FUNCTION_GAMMA22 ?
                                        gamma_type_index_2_2_flat : gamma_type_index_2_2);
        }
        map_regamma_hw_to_x_user(ramp, coeff, rgb_user,
                        coordinates_x, axis_x, rgb_regamma,
                        MAX_HW_POINTS, tf_pts,
                        (mapUserRamp || (ramp && ramp->type != GAMMA_RGB_256)) &&
                        (ramp && ramp->type != GAMMA_CS_TFM_1D));

        if (ramp && ramp->type == GAMMA_CS_TFM_1D)
                apply_lut_1d(ramp, MAX_HW_POINTS, tf_pts);

        ret = true;

        kvfree(coeff);
coeff_alloc_fail:
        kvfree(rgb_regamma);
rgb_regamma_alloc_fail:
        kvfree(axis_x);
axis_x_alloc_fail:
        kvfree(rgb_user);
rgb_user_alloc_fail:
        return ret;
}

bool calculate_user_regamma_coeff(struct dc_transfer_func *output_tf,
                const struct regamma_lut *regamma)
{
        struct gamma_coefficients coeff;
        const struct hw_x_point *coord_x = coordinates_x;
        uint32_t i = 0;

        do {
                coeff.a0[i] = dc_fixpt_from_fraction(
                                regamma->coeff.A0[i], 10000000);
                coeff.a1[i] = dc_fixpt_from_fraction(
                                regamma->coeff.A1[i], 1000);
                coeff.a2[i] = dc_fixpt_from_fraction(
                                regamma->coeff.A2[i], 1000);
                coeff.a3[i] = dc_fixpt_from_fraction(
                                regamma->coeff.A3[i], 1000);
                coeff.user_gamma[i] = dc_fixpt_from_fraction(
                                regamma->coeff.gamma[i], 1000);

                ++i;
        } while (i != 3);

        i = 0;
        /* fixed_pt library has problems handling too small values */
        while (i != 32) {
                output_tf->tf_pts.red[i] = dc_fixpt_zero;
                output_tf->tf_pts.green[i] = dc_fixpt_zero;
                output_tf->tf_pts.blue[i] = dc_fixpt_zero;
                ++coord_x;
                ++i;
        }
        while (i != MAX_HW_POINTS + 1) {
                output_tf->tf_pts.red[i] = translate_from_linear_space_ex(
                                coord_x->x, &coeff, 0);
                output_tf->tf_pts.green[i] = translate_from_linear_space_ex(
                                coord_x->x, &coeff, 1);
                output_tf->tf_pts.blue[i] = translate_from_linear_space_ex(
                                coord_x->x, &coeff, 2);
                ++coord_x;
                ++i;
        }

        // this function just clamps output to 0-1
        build_new_custom_resulted_curve(MAX_HW_POINTS, &output_tf->tf_pts);
        output_tf->type = TF_TYPE_DISTRIBUTED_POINTS;

        return true;
}

bool calculate_user_regamma_ramp(struct dc_transfer_func *output_tf,
                const struct regamma_lut *regamma)
{
        struct dc_transfer_func_distributed_points *tf_pts = &output_tf->tf_pts;
        struct dividers dividers;

        struct pwl_float_data *rgb_user = NULL;
        struct pwl_float_data_ex *rgb_regamma = NULL;
        bool ret = false;

        if (regamma == NULL)
                return false;

        output_tf->type = TF_TYPE_DISTRIBUTED_POINTS;

        rgb_user = kcalloc(GAMMA_RGB_256_ENTRIES + _EXTRA_POINTS,
                           sizeof(*rgb_user),
                           GFP_KERNEL);
        if (!rgb_user)
                goto rgb_user_alloc_fail;

        rgb_regamma = kcalloc(MAX_HW_POINTS + _EXTRA_POINTS,
                              sizeof(*rgb_regamma),
                              GFP_KERNEL);
        if (!rgb_regamma)
                goto rgb_regamma_alloc_fail;

        dividers.divider1 = dc_fixpt_from_fraction(3, 2);
        dividers.divider2 = dc_fixpt_from_int(2);
        dividers.divider3 = dc_fixpt_from_fraction(5, 2);

        scale_user_regamma_ramp(rgb_user, &regamma->ramp, dividers);

        if (regamma->flags.bits.applyDegamma == 1) {
                apply_degamma_for_user_regamma(rgb_regamma, MAX_HW_POINTS);
                copy_rgb_regamma_to_coordinates_x(coordinates_x,
                                MAX_HW_POINTS, rgb_regamma);
        }

        interpolate_user_regamma(MAX_HW_POINTS, rgb_user,
                        regamma->flags.bits.applyDegamma, tf_pts);

        // no custom HDR curves!
        tf_pts->end_exponent = 0;
        tf_pts->x_point_at_y1_red = 1;
        tf_pts->x_point_at_y1_green = 1;
        tf_pts->x_point_at_y1_blue = 1;

        // this function just clamps output to 0-1
        build_new_custom_resulted_curve(MAX_HW_POINTS, tf_pts);

        ret = true;

        kfree(rgb_regamma);
rgb_regamma_alloc_fail:
        kvfree(rgb_user);
rgb_user_alloc_fail:
        return ret;
}

bool mod_color_calculate_degamma_params(struct dc_transfer_func *input_tf,
                const struct dc_gamma *ramp, bool mapUserRamp)
{
        struct dc_transfer_func_distributed_points *tf_pts = &input_tf->tf_pts;
        struct dividers dividers;
        struct pwl_float_data *rgb_user = NULL;
        struct pwl_float_data_ex *curve = NULL;
        struct gamma_pixel *axis_x = NULL;
        struct pixel_gamma_point *coeff = NULL;
        enum dc_transfer_func_predefined tf = TRANSFER_FUNCTION_SRGB;
        uint32_t i;
        bool ret = false;

        if (input_tf->type == TF_TYPE_BYPASS)
                return false;

        /* we can use hardcoded curve for plain SRGB TF
         * If linear, it's bypass if on user ramp
         */
        if (input_tf->type == TF_TYPE_PREDEFINED &&
                        (input_tf->tf == TRANSFER_FUNCTION_SRGB ||
                                        input_tf->tf == TRANSFER_FUNCTION_LINEAR) &&
                                        !mapUserRamp)
                return true;

        input_tf->type = TF_TYPE_DISTRIBUTED_POINTS;

        if (mapUserRamp && ramp && ramp->type == GAMMA_RGB_256) {
                rgb_user = kvcalloc(ramp->num_entries + _EXTRA_POINTS,
                                sizeof(*rgb_user),
                                GFP_KERNEL);
                if (!rgb_user)
                        goto rgb_user_alloc_fail;

                axis_x = kvcalloc(ramp->num_entries + _EXTRA_POINTS, sizeof(*axis_x),
                                GFP_KERNEL);
                if (!axis_x)
                        goto axis_x_alloc_fail;

                dividers.divider1 = dc_fixpt_from_fraction(3, 2);
                dividers.divider2 = dc_fixpt_from_int(2);
                dividers.divider3 = dc_fixpt_from_fraction(5, 2);

                build_evenly_distributed_points(
                                axis_x,
                                ramp->num_entries,
                                dividers);

                scale_gamma(rgb_user, ramp, dividers);
        }

        curve = kvcalloc(MAX_HW_POINTS + _EXTRA_POINTS, sizeof(*curve),
                        GFP_KERNEL);
        if (!curve)
                goto curve_alloc_fail;

        coeff = kvcalloc(MAX_HW_POINTS + _EXTRA_POINTS, sizeof(*coeff),
                        GFP_KERNEL);
        if (!coeff)
                goto coeff_alloc_fail;

        tf = input_tf->tf;

        if (tf == TRANSFER_FUNCTION_PQ)
                build_de_pq(curve,
                                MAX_HW_POINTS,
                                coordinates_x);
        else if (tf == TRANSFER_FUNCTION_SRGB ||
                        tf == TRANSFER_FUNCTION_BT709)
                build_degamma(curve,
                                MAX_HW_POINTS,
                                coordinates_x,
                                tf == TRANSFER_FUNCTION_SRGB ?
                                gamma_type_index_2_4 : tf == TRANSFER_FUNCTION_GAMMA22 ?
                                gamma_type_index_2_2_flat : gamma_type_index_2_2);
        else if (tf == TRANSFER_FUNCTION_LINEAR) {
                // just copy coordinates_x into curve
                i = 0;
                while (i != MAX_HW_POINTS + 1) {
                        curve[i].r = coordinates_x[i].x;
                        curve[i].g = curve[i].r;
                        curve[i].b = curve[i].r;
                        i++;
                }
        } else
                goto invalid_tf_fail;

        tf_pts->end_exponent = 0;
        tf_pts->x_point_at_y1_red = 1;
        tf_pts->x_point_at_y1_green = 1;
        tf_pts->x_point_at_y1_blue = 1;

        map_regamma_hw_to_x_user(ramp, coeff, rgb_user,
                        coordinates_x, axis_x, curve,
                        MAX_HW_POINTS, tf_pts,
                        mapUserRamp && ramp && ramp->type == GAMMA_RGB_256);
        if (ramp->type == GAMMA_CUSTOM)
                apply_lut_1d(ramp, MAX_HW_POINTS, tf_pts);

        ret = true;

invalid_tf_fail:
        kvfree(coeff);
coeff_alloc_fail:
        kvfree(curve);
curve_alloc_fail:
        kvfree(axis_x);
axis_x_alloc_fail:
        kvfree(rgb_user);
rgb_user_alloc_fail:

        return ret;
}


bool  mod_color_calculate_curve(enum dc_transfer_func_predefined trans,
                                struct dc_transfer_func_distributed_points *points,
                                uint32_t sdr_ref_white_level)
{
        uint32_t i;
        bool ret = false;
        struct pwl_float_data_ex *rgb_regamma = NULL;

        if (trans == TRANSFER_FUNCTION_UNITY ||
                trans == TRANSFER_FUNCTION_LINEAR) {
                points->end_exponent = 0;
                points->x_point_at_y1_red = 1;
                points->x_point_at_y1_green = 1;
                points->x_point_at_y1_blue = 1;

                for (i = 0; i <= MAX_HW_POINTS ; i++) {
                        points->red[i]    = coordinates_x[i].x;
                        points->green[i]  = coordinates_x[i].x;
                        points->blue[i]   = coordinates_x[i].x;
                }
                ret = true;
        } else if (trans == TRANSFER_FUNCTION_PQ) {
                rgb_regamma = kvcalloc(MAX_HW_POINTS + _EXTRA_POINTS,
                                       sizeof(*rgb_regamma),
                                       GFP_KERNEL);
                if (!rgb_regamma)
                        goto rgb_regamma_alloc_fail;
                points->end_exponent = 7;
                points->x_point_at_y1_red = 125;
                points->x_point_at_y1_green = 125;
                points->x_point_at_y1_blue = 125;


                build_pq(rgb_regamma,
                                MAX_HW_POINTS,
                                coordinates_x,
                                sdr_ref_white_level);
                for (i = 0; i <= MAX_HW_POINTS ; i++) {
                        points->red[i]    = rgb_regamma[i].r;
                        points->green[i]  = rgb_regamma[i].g;
                        points->blue[i]   = rgb_regamma[i].b;
                }
                ret = true;

                kvfree(rgb_regamma);
        } else if (trans == TRANSFER_FUNCTION_SRGB ||
                          trans == TRANSFER_FUNCTION_BT709) {
                rgb_regamma = kvcalloc(MAX_HW_POINTS + _EXTRA_POINTS,
                                       sizeof(*rgb_regamma),
                                       GFP_KERNEL);
                if (!rgb_regamma)
                        goto rgb_regamma_alloc_fail;
                points->end_exponent = 0;
                points->x_point_at_y1_red = 1;
                points->x_point_at_y1_green = 1;
                points->x_point_at_y1_blue = 1;

                build_regamma(rgb_regamma,
                                MAX_HW_POINTS,
                                coordinates_x,
                                trans == TRANSFER_FUNCTION_SRGB ?
                                gamma_type_index_2_4 : trans == TRANSFER_FUNCTION_GAMMA22 ?
                                gamma_type_index_2_2_flat : gamma_type_index_2_2);
                for (i = 0; i <= MAX_HW_POINTS ; i++) {
                        points->red[i]    = rgb_regamma[i].r;
                        points->green[i]  = rgb_regamma[i].g;
                        points->blue[i]   = rgb_regamma[i].b;
                }
                ret = true;

                kvfree(rgb_regamma);
        } else if (trans == TRANSFER_FUNCTION_HLG ||
                trans == TRANSFER_FUNCTION_HLG12) {
                rgb_regamma = kvcalloc(MAX_HW_POINTS + _EXTRA_POINTS,
                                       sizeof(*rgb_regamma),
                                       GFP_KERNEL);
                if (!rgb_regamma)
                        goto rgb_regamma_alloc_fail;

                build_hlg_regamma(rgb_regamma,
                                MAX_HW_POINTS,
                                coordinates_x,
                                trans == TRANSFER_FUNCTION_HLG12 ? true:false);
                for (i = 0; i <= MAX_HW_POINTS ; i++) {
                        points->red[i]    = rgb_regamma[i].r;
                        points->green[i]  = rgb_regamma[i].g;
                        points->blue[i]   = rgb_regamma[i].b;
                }
                ret = true;
                kvfree(rgb_regamma);
        }
rgb_regamma_alloc_fail:
        return ret;
}


bool  mod_color_calculate_degamma_curve(enum dc_transfer_func_predefined trans,
                                struct dc_transfer_func_distributed_points *points)
{
        uint32_t i;
        bool ret = false;
        struct pwl_float_data_ex *rgb_degamma = NULL;

        if (trans == TRANSFER_FUNCTION_UNITY ||
                trans == TRANSFER_FUNCTION_LINEAR) {

                for (i = 0; i <= MAX_HW_POINTS ; i++) {
                        points->red[i]    = coordinates_x[i].x;
                        points->green[i]  = coordinates_x[i].x;
                        points->blue[i]   = coordinates_x[i].x;
                }
                ret = true;
        } else if (trans == TRANSFER_FUNCTION_PQ) {
                rgb_degamma = kvcalloc(MAX_HW_POINTS + _EXTRA_POINTS,
                                       sizeof(*rgb_degamma),
                                       GFP_KERNEL);
                if (!rgb_degamma)
                        goto rgb_degamma_alloc_fail;


                build_de_pq(rgb_degamma,
                                MAX_HW_POINTS,
                                coordinates_x);
                for (i = 0; i <= MAX_HW_POINTS ; i++) {
                        points->red[i]    = rgb_degamma[i].r;
                        points->green[i]  = rgb_degamma[i].g;
                        points->blue[i]   = rgb_degamma[i].b;
                }
                ret = true;

                kvfree(rgb_degamma);
        } else if (trans == TRANSFER_FUNCTION_SRGB ||
                          trans == TRANSFER_FUNCTION_BT709 ||
                          trans == TRANSFER_FUNCTION_GAMMA22) {
                rgb_degamma = kvcalloc(MAX_HW_POINTS + _EXTRA_POINTS,
                                       sizeof(*rgb_degamma),
                                       GFP_KERNEL);
                if (!rgb_degamma)
                        goto rgb_degamma_alloc_fail;

                build_degamma(rgb_degamma,
                                MAX_HW_POINTS,
                                coordinates_x,
                                trans == TRANSFER_FUNCTION_SRGB ?
                                gamma_type_index_2_4 : trans == TRANSFER_FUNCTION_GAMMA22 ?
                                gamma_type_index_2_2_flat : gamma_type_index_2_2);
                for (i = 0; i <= MAX_HW_POINTS ; i++) {
                        points->red[i]    = rgb_degamma[i].r;
                        points->green[i]  = rgb_degamma[i].g;
                        points->blue[i]   = rgb_degamma[i].b;
                }
                ret = true;

                kvfree(rgb_degamma);
        } else if (trans == TRANSFER_FUNCTION_HLG ||
                trans == TRANSFER_FUNCTION_HLG12) {
                rgb_degamma = kvcalloc(MAX_HW_POINTS + _EXTRA_POINTS,
                                       sizeof(*rgb_degamma),
                                       GFP_KERNEL);
                if (!rgb_degamma)
                        goto rgb_degamma_alloc_fail;

                build_hlg_degamma(rgb_degamma,
                                MAX_HW_POINTS,
                                coordinates_x,
                                trans == TRANSFER_FUNCTION_HLG12 ? true:false);
                for (i = 0; i <= MAX_HW_POINTS ; i++) {
                        points->red[i]    = rgb_degamma[i].r;
                        points->green[i]  = rgb_degamma[i].g;
                        points->blue[i]   = rgb_degamma[i].b;
                }
                ret = true;
                kvfree(rgb_degamma);
        }
        points->end_exponent = 0;
        points->x_point_at_y1_red = 1;
        points->x_point_at_y1_green = 1;
        points->x_point_at_y1_blue = 1;

rgb_degamma_alloc_fail:
        return ret;
}