/*
 * 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 <linux/slab.h>

#include <math_support.h>
#include "sh_css_param_shading.h"
#include "ia_css_shading.h"
#include "assert_support.h"
#include "sh_css_defs.h"
#include "sh_css_internal.h"
#include "ia_css_debug.h"
#include "ia_css_pipe_binarydesc.h"

#include "sh_css_hrt.h"

#include "platform_support.h"

/* Bilinear interpolation on shading tables:
 * For each target point T, we calculate the 4 surrounding source points:
 * ul (upper left), ur (upper right), ll (lower left) and lr (lower right).
 * We then calculate the distances from the T to the source points: x0, x1,
 * y0 and y1.
 * We then calculate the value of T:
 *   dx0*dy0*Slr + dx0*dy1*Sur + dx1*dy0*Sll + dx1*dy1*Sul.
 * We choose a grid size of 1x1 which means:
 *   dx1 = 1-dx0
 *   dy1 = 1-dy0
 *
 *   Sul dx0         dx1      Sur
 *    .<----->|<------------->.
 *    ^
 * dy0|
 *    v        T
 *    -        .
 *    ^
 *    |
 * dy1|
 *    v
 *    .                        .
 *   Sll                      Slr
 *
 * Padding:
 * The area that the ISP operates on can include padding both on the left
 * and the right. We need to padd the shading table such that the shading
 * values end up on the correct pixel values. This means we must padd the
 * shading table to match the ISP padding.
 * We can have 5 cases:
 * 1. All 4 points fall in the left padding.
 * 2. The left 2 points fall in the left padding.
 * 3. All 4 points fall in the cropped (target) region.
 * 4. The right 2 points fall in the right padding.
 * 5. All 4 points fall in the right padding.
 * Cases 1 and 5 are easy to handle: we simply use the
 * value 1 in the shading table.
 * Cases 2 and 4 require interpolation that takes into
 * account how far into the padding area the pixels
 * fall. We extrapolate the shading table into the
 * padded area and then interpolate.
 */
static void
crop_and_interpolate(unsigned int cropped_width,
                     unsigned int cropped_height,
                     unsigned int left_padding,
                     int right_padding,
                     int top_padding,
                     const struct ia_css_shading_table *in_table,
                     struct ia_css_shading_table *out_table,
                     enum ia_css_sc_color color)
{
        unsigned int i, j,
                     sensor_width,
                     sensor_height,
                     table_width,
                     table_height,
                     table_cell_h,
                     out_cell_size,
                     in_cell_size,
                     out_start_row,
                     padded_width;
        int out_start_col, /* can be negative to indicate padded space */
            table_cell_w;
        unsigned short *in_ptr,
                       *out_ptr;

        assert(in_table != NULL);
        assert(out_table != NULL);

        sensor_width  = in_table->sensor_width;
        sensor_height = in_table->sensor_height;
        table_width   = in_table->width;
        table_height  = in_table->height;
        in_ptr = in_table->data[color];
        out_ptr = out_table->data[color];

        padded_width = cropped_width + left_padding + right_padding;
        out_cell_size = CEIL_DIV(padded_width, out_table->width - 1);
        in_cell_size  = CEIL_DIV(sensor_width, table_width - 1);

        out_start_col = ((int)sensor_width - (int)cropped_width)/2 - left_padding;
        out_start_row = ((int)sensor_height - (int)cropped_height)/2 - top_padding;
        table_cell_w = (int)((table_width-1) * in_cell_size);
        table_cell_h = (table_height-1) * in_cell_size;

        for (i = 0; i < out_table->height; i++) {
                int ty, src_y0, src_y1;
                unsigned int sy0, sy1, dy0, dy1, divy;

                /* calculate target point and make sure it falls within
                   the table */
                ty = out_start_row + i * out_cell_size;

                /* calculate closest source points in shading table and
                   make sure they fall within the table */
                src_y0 = ty / (int)in_cell_size;
                if (in_cell_size < out_cell_size)
                        src_y1 = (ty + out_cell_size) / in_cell_size;
                else
                        src_y1 = src_y0 + 1;
                src_y0 = clamp(src_y0, 0, (int)table_height-1);
                src_y1 = clamp(src_y1, 0, (int)table_height-1);
                ty = min(clamp(ty, 0, (int)sensor_height-1),
                                 (int)table_cell_h);

                /* calculate closest source points for distance computation */
                sy0 = min(src_y0 * in_cell_size, sensor_height-1);
                sy1 = min(src_y1 * in_cell_size, sensor_height-1);
                /* calculate distance between source and target pixels */
                dy0 = ty - sy0;
                dy1 = sy1 - ty;
                divy = sy1 - sy0;
                if (divy == 0) {
                        dy0 = 1;
                        divy = 1;
                }

                for (j = 0; j < out_table->width; j++, out_ptr++) {
                        int tx, src_x0, src_x1;
                        unsigned int sx0, sx1, dx0, dx1, divx;
                        unsigned short s_ul, s_ur, s_ll, s_lr;

                        /* calculate target point */
                        tx = out_start_col + j * out_cell_size;
                        /* calculate closest source points. */
                        src_x0 = tx / (int)in_cell_size;
                        if (in_cell_size < out_cell_size) {
                                src_x1 = (tx + out_cell_size) /
                                         (int)in_cell_size;
                        } else {
                                src_x1 = src_x0 + 1;
                        }
                        /* if src points fall in padding, select closest ones.*/
                        src_x0 = clamp(src_x0, 0, (int)table_width-1);
                        src_x1 = clamp(src_x1, 0, (int)table_width-1);
                        tx = min(clamp(tx, 0, (int)sensor_width-1),
                                 (int)table_cell_w);
                        /* calculate closest source points for distance
                           computation */
                        sx0 = min(src_x0 * in_cell_size, sensor_width-1);
                        sx1 = min(src_x1 * in_cell_size, sensor_width-1);
                        /* calculate distances between source and target
                           pixels */
                        dx0 = tx - sx0;
                        dx1 = sx1 - tx;
                        divx = sx1 - sx0;
                        /* if we're at the edge, we just use the closest
                           point still in the grid. We make up for the divider
                           in this case by setting the distance to
                           out_cell_size, since it's actually 0. */
                        if (divx == 0) {
                                dx0 = 1;
                                divx = 1;
                        }

                        /* get source pixel values */
                        s_ul = in_ptr[(table_width*src_y0)+src_x0];
                        s_ur = in_ptr[(table_width*src_y0)+src_x1];
                        s_ll = in_ptr[(table_width*src_y1)+src_x0];
                        s_lr = in_ptr[(table_width*src_y1)+src_x1];

                        *out_ptr = (unsigned short) ((dx0*dy0*s_lr + dx0*dy1*s_ur + dx1*dy0*s_ll + dx1*dy1*s_ul) /
                                        (divx*divy));
                }
        }
}

void
sh_css_params_shading_id_table_generate(
        struct ia_css_shading_table **target_table,
#ifndef ISP2401
        const struct ia_css_binary *binary)
#else
        unsigned int table_width,
        unsigned int table_height)
#endif
{
        /* initialize table with ones, shift becomes zero */
#ifndef ISP2401
        unsigned int i, j, table_width, table_height;
#else
        unsigned int i, j;
#endif
        struct ia_css_shading_table *result;

        assert(target_table != NULL);
#ifndef ISP2401
        assert(binary != NULL);
#endif

#ifndef ISP2401
        table_width  = binary->sctbl_width_per_color;
        table_height = binary->sctbl_height;
#endif
        result = ia_css_shading_table_alloc(table_width, table_height);
        if (result == NULL) {
                *target_table = NULL;
                return;
        }

        for (i = 0; i < IA_CSS_SC_NUM_COLORS; i++) {
                for (j = 0; j < table_height * table_width; j++)
                        result->data[i][j] = 1;
        }
        result->fraction_bits = 0;
        *target_table = result;
}

void
prepare_shading_table(const struct ia_css_shading_table *in_table,
                      unsigned int sensor_binning,
                      struct ia_css_shading_table **target_table,
                      const struct ia_css_binary *binary,
                      unsigned int bds_factor)
{
        unsigned int input_width,
                     input_height,
                     table_width,
                     table_height,
                     left_padding,
                     top_padding,
                     padded_width,
                     left_cropping,
                     i;
        unsigned int bds_numerator, bds_denominator;
        int right_padding;

        struct ia_css_shading_table *result;

        assert(target_table != NULL);
        assert(binary != NULL);

        if (!in_table) {
#ifndef ISP2401
                sh_css_params_shading_id_table_generate(target_table, binary);
#else
                sh_css_params_shading_id_table_generate(target_table,
                        binary->sctbl_legacy_width_per_color, binary->sctbl_legacy_height);
#endif
                return;
        }

        padded_width = binary->in_frame_info.padded_width;
        /* We use the ISP input resolution for the shading table because
           shading correction is performed in the bayer domain (before bayer
           down scaling). */
#if defined(USE_INPUT_SYSTEM_VERSION_2401)
        padded_width = CEIL_MUL(binary->effective_in_frame_res.width + 2*ISP_VEC_NELEMS,
                                        2*ISP_VEC_NELEMS);
#endif
        input_height  = binary->in_frame_info.res.height;
        input_width   = binary->in_frame_info.res.width;
        left_padding  = binary->left_padding;
        left_cropping = (binary->info->sp.pipeline.left_cropping == 0) ?
                        binary->dvs_envelope.width : 2*ISP_VEC_NELEMS;

        sh_css_bds_factor_get_numerator_denominator
                (bds_factor, &bds_numerator, &bds_denominator);

        left_padding  = (left_padding + binary->info->sp.pipeline.left_cropping) * bds_numerator / bds_denominator - binary->info->sp.pipeline.left_cropping;
        right_padding = (binary->internal_frame_info.res.width - binary->effective_in_frame_res.width * bds_denominator / bds_numerator - left_cropping) * bds_numerator / bds_denominator;
        top_padding = binary->info->sp.pipeline.top_cropping * bds_numerator / bds_denominator - binary->info->sp.pipeline.top_cropping;

#if !defined(USE_WINDOWS_BINNING_FACTOR)
        /* @deprecated{This part of the code will be replaced by the code
         * in the #else section below to make the calculation same across
         * all platforms.
         * Android and Windows platforms interpret the binning_factor parameter
         * differently. In Android, the binning factor is expressed in the form
         * 2^N * 2^N, whereas in Windows platform, the binning factor is N*N}
         */

        /* We take into account the binning done by the sensor. We do this
           by cropping the non-binned part of the shading table and then
           increasing the size of a grid cell with this same binning factor. */
        input_width  <<= sensor_binning;
        input_height <<= sensor_binning;
        /* We also scale the padding by the same binning factor. This will
           make it much easier later on to calculate the padding of the
           shading table. */
        left_padding  <<= sensor_binning;
        right_padding <<= sensor_binning;
        top_padding   <<= sensor_binning;
#else
        input_width   *= sensor_binning;
        input_height  *= sensor_binning;
        left_padding  *= sensor_binning;
        right_padding *= sensor_binning;
        top_padding   *= sensor_binning;
#endif /*USE_WINDOWS_BINNING_FACTOR*/

        /* during simulation, the used resolution can exceed the sensor
           resolution, so we clip it. */
        input_width  = min(input_width,  in_table->sensor_width);
        input_height = min(input_height, in_table->sensor_height);

#ifndef ISP2401
        table_width  = binary->sctbl_width_per_color;
        table_height = binary->sctbl_height;
#else
        /* This prepare_shading_table() function is called only in legacy API (not in new API).
           Then, the legacy shading table width and height should be used. */
        table_width  = binary->sctbl_legacy_width_per_color;
        table_height = binary->sctbl_legacy_height;
#endif

        result = ia_css_shading_table_alloc(table_width, table_height);
        if (result == NULL) {
                *target_table = NULL;
                return;
        }
        result->sensor_width  = in_table->sensor_width;
        result->sensor_height = in_table->sensor_height;
        result->fraction_bits = in_table->fraction_bits;

        /* now we crop the original shading table and then interpolate to the
           requested resolution and decimation factor. */
        for (i = 0; i < IA_CSS_SC_NUM_COLORS; i++) {
                crop_and_interpolate(input_width, input_height,
                                     left_padding, right_padding, top_padding,
                                     in_table,
                                     result, i);
        }
        *target_table = result;
}

struct ia_css_shading_table *
ia_css_shading_table_alloc(
        unsigned int width,
        unsigned int height)
{
        unsigned int i;
        struct ia_css_shading_table *me;

        IA_CSS_ENTER("");

        me = kmalloc(sizeof(*me), GFP_KERNEL);
        if (me == NULL) {
                IA_CSS_ERROR("out of memory");
                return me;
        }

        me->width         = width;
        me->height        = height;
        me->sensor_width  = 0;
        me->sensor_height = 0;
        me->fraction_bits = 0;
        for (i = 0; i < IA_CSS_SC_NUM_COLORS; i++) {
                me->data[i] =
                    sh_css_malloc(width * height * sizeof(*me->data[0]));
                if (me->data[i] == NULL) {
                        unsigned int j;
                        for (j = 0; j < i; j++) {
                                sh_css_free(me->data[j]);
                                me->data[j] = NULL;
                        }
                        kfree(me);
                        return NULL;
                }
        }

        IA_CSS_LEAVE("");
        return me;
}

void
ia_css_shading_table_free(struct ia_css_shading_table *table)
{
        unsigned int i;

        if (table == NULL)
                return;

        /* We only output logging when the table is not NULL, otherwise
         * logs will give the impression that a table was freed.
         * */
        IA_CSS_ENTER("");

        for (i = 0; i < IA_CSS_SC_NUM_COLORS; i++) {
                if (table->data[i]) {
                        sh_css_free(table->data[i]);
                        table->data[i] = NULL;
                }
        }
        kfree(table);

        IA_CSS_LEAVE("");
}