// SPDX-License-Identifier: GPL-2.0
/*
 * Support for Intel Camera Imaging ISP subsystem.
 * Copyright (c) 2015, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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 "ia_css_types.h"
#include "sh_css_defs.h"
#include "assert_support.h"

#include "ia_css_ctc2.host.h"

#define INEFFECTIVE_VAL 4096
#define BASIC_VAL 819

/*Default configuration of parameters for Ctc2*/
const struct ia_css_ctc2_config default_ctc2_config = {
        INEFFECTIVE_VAL, INEFFECTIVE_VAL, INEFFECTIVE_VAL,
        INEFFECTIVE_VAL, INEFFECTIVE_VAL, INEFFECTIVE_VAL,
        BASIC_VAL * 2, BASIC_VAL * 4, BASIC_VAL * 6,
        BASIC_VAL * 8, INEFFECTIVE_VAL, INEFFECTIVE_VAL,
        BASIC_VAL >> 1, BASIC_VAL
};

/* (dydx) = ctc2_slope(y1, y0, x1, x0)
 * -----------------------------------------------
 * Calculation of the Slope of a Line = ((y1 - y0) >> 8)/(x1 - x0)
 *
 * Note: y1, y0 , x1 & x0 must lie within the range 0 <-> 8191
 */
static int ctc2_slope(int y1, int y0, int x1, int x0)
{
        const int shift_val = 8;
        const int max_slope = (1 << IA_CSS_CTC_COEF_SHIFT) - 1;
        int dy = y1 - y0;
        int dx = x1 - x0;
        int rounding = (dx + 1) >> 1;
        int dy_shift = dy << shift_val;
        int slope, dydx;

        /*Protection for parameter values, & avoiding zero divisions*/
        assert(y0 >= 0 && y0 <= max_slope);
        assert(y1 >= 0 && y1 <= max_slope);
        assert(x0 >= 0 && x0 <= max_slope);
        assert(x1 > 0 && x1 <= max_slope);
        assert(dx > 0);

        if (dy < 0)
                rounding = -rounding;
        slope = (int)(dy_shift + rounding) / dx;

        /*the slope must lie within the range
          (-max_slope-1) >= (dydx) >= (max_slope)
        */
        if (slope <= -max_slope - 1) {
                dydx = -max_slope - 1;
        } else if (slope >= max_slope) {
                dydx = max_slope;
        } else {
                dydx = slope;
        }

        return dydx;
}

/* (void) = ia_css_ctc2_vmem_encode(*to, *from)
 * -----------------------------------------------
 * VMEM Encode Function to translate Y parameters from userspace into ISP space
 */
void ia_css_ctc2_vmem_encode(struct ia_css_isp_ctc2_vmem_params *to,
                             const struct ia_css_ctc2_config *from,
                             size_t size)
{
        unsigned int i, j;
        const unsigned int shffl_blck = 4;
        const unsigned int length_zeros = 11;
        short dydx0, dydx1, dydx2, dydx3, dydx4;

        (void)size;
        /*
        *  Calculation of slopes of lines interconnecting
        *  0.0 -> y_x1 -> y_x2 -> y _x3 -> y_x4 -> 1.0
        */
        dydx0 = ctc2_slope(from->y_y1, from->y_y0,
                           from->y_x1, 0);
        dydx1 = ctc2_slope(from->y_y2, from->y_y1,
                           from->y_x2, from->y_x1);
        dydx2 = ctc2_slope(from->y_y3, from->y_y2,
                           from->y_x3, from->y_x2);
        dydx3 = ctc2_slope(from->y_y4, from->y_y3,
                           from->y_x4, from->y_x3);
        dydx4 = ctc2_slope(from->y_y5, from->y_y4,
                           SH_CSS_BAYER_MAXVAL, from->y_x4);

        /*Fill 3 arrays with:
         * - Luma input gain values y_y0, y_y1, y_y2, y_3, y_y4
         * - Luma kneepoints 0, y_x1, y_x2, y_x3, y_x4
         * - Calculated slopes dydx0, dyxd1, dydx2, dydx3, dydx4
         *
         * - Each 64-element array is divided in blocks of 16 elements:
         *   the 5 parameters + zeros in the remaining 11 positions
         * - All blocks of the same array will contain the same data
         */
        for (i = 0; i < shffl_blck; i++) {
                to->y_x[0][(i << shffl_blck)]     = 0;
                to->y_x[0][(i << shffl_blck) + 1] = from->y_x1;
                to->y_x[0][(i << shffl_blck) + 2] = from->y_x2;
                to->y_x[0][(i << shffl_blck) + 3] = from->y_x3;
                to->y_x[0][(i << shffl_blck) + 4] = from->y_x4;

                to->y_y[0][(i << shffl_blck)]     = from->y_y0;
                to->y_y[0][(i << shffl_blck) + 1] = from->y_y1;
                to->y_y[0][(i << shffl_blck) + 2] = from->y_y2;
                to->y_y[0][(i << shffl_blck) + 3] = from->y_y3;
                to->y_y[0][(i << shffl_blck) + 4] = from->y_y4;

                to->e_y_slope[0][(i << shffl_blck)]    = dydx0;
                to->e_y_slope[0][(i << shffl_blck) + 1] = dydx1;
                to->e_y_slope[0][(i << shffl_blck) + 2] = dydx2;
                to->e_y_slope[0][(i << shffl_blck) + 3] = dydx3;
                to->e_y_slope[0][(i << shffl_blck) + 4] = dydx4;

                for (j = 0; j < length_zeros; j++) {
                        to->y_x[0][(i << shffl_blck) + 5 + j] = 0;
                        to->y_y[0][(i << shffl_blck) + 5 + j] = 0;
                        to->e_y_slope[0][(i << shffl_blck) + 5 + j] = 0;
                }
        }
}

/* (void) = ia_css_ctc2_encode(*to, *from)
 * -----------------------------------------------
 * DMEM Encode Function to translate UV parameters from userspace into ISP space
 */
void ia_css_ctc2_encode(struct ia_css_isp_ctc2_dmem_params *to,
                        struct ia_css_ctc2_config *from,
                        size_t size)
{
        (void)size;

        to->uv_y0 = from->uv_y0;
        to->uv_y1 = from->uv_y1;
        to->uv_x0 = from->uv_x0;
        to->uv_x1 = from->uv_x1;

        /*Slope Calculation*/
        to->uv_dydx = ctc2_slope(from->uv_y1, from->uv_y0,
                                 from->uv_x1, from->uv_x0);
}