LXR linux/drivers/gpu/drm/amd/display/dc/calcs/dcn_calc

   1/*
   2 * Copyright 2017 Advanced Micro Devices, Inc.
   3 *
   4 * Permission is hereby granted, free of charge, to any person obtaining a
   5 * copy of this software and associated documentation files (the "Software"),
   6 * to deal in the Software without restriction, including without limitation
   7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8 * and/or sell copies of the Software, and to permit persons to whom the
   9 * Software is furnished to do so, subject to the following conditions:
  10 *
  11 * The above copyright notice and this permission notice shall be included in
  12 * all copies or substantial portions of the Software.
  13 *
  14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  20 * OTHER DEALINGS IN THE SOFTWARE.
  21 *
  22 * Authors: AMD
  23 *
  24 */
  25
  26#include "dcn_calc_math.h"
  27
  28#define isNaN(number) ((number) != (number))
  29
  30/*
  31 * NOTE:
  32 *   This file is gcc-parseable HW gospel, coming straight from HW engineers.
  33 *
  34 * It doesn't adhere to Linux kernel style and sometimes will do things in odd
  35 * ways. Unless there is something clearly wrong with it the code should
  36 * remain as-is as it provides us with a guarantee from HW that it is correct.
  37 */
  38
  39float dcn_bw_mod(const float arg1, const float arg2)
  40{
  41        if (isNaN(arg1))
  42                return arg2;
  43        if (isNaN(arg2))
  44                return arg1;
  45        return arg1 - arg1 * ((int) (arg1 / arg2));
  46}
  47
  48float dcn_bw_min2(const float arg1, const float arg2)
  49{
  50        if (isNaN(arg1))
  51                return arg2;
  52        if (isNaN(arg2))
  53                return arg1;
  54        return arg1 < arg2 ? arg1 : arg2;
  55}
  56
  57unsigned int dcn_bw_max(const unsigned int arg1, const unsigned int arg2)
  58{
  59        return arg1 > arg2 ? arg1 : arg2;
  60}
  61float dcn_bw_max2(const float arg1, const float arg2)
  62{
  63        if (isNaN(arg1))
  64                return arg2;
  65        if (isNaN(arg2))
  66                return arg1;
  67        return arg1 > arg2 ? arg1 : arg2;
  68}
  69
  70float dcn_bw_floor2(const float arg, const float significance)
  71{
  72        if (significance == 0)
  73                return 0;
  74        return ((int) (arg / significance)) * significance;
  75}
  76
  77float dcn_bw_ceil2(const float arg, const float significance)
  78{
  79        float flr = dcn_bw_floor2(arg, significance);
  80        if (significance == 0)
  81                return 0;
  82        return flr + 0.00001 >= arg ? arg : flr + significance;
  83}
  84
  85float dcn_bw_max3(float v1, float v2, float v3)
  86{
  87        return v3 > dcn_bw_max2(v1, v2) ? v3 : dcn_bw_max2(v1, v2);
  88}
  89
  90float dcn_bw_max5(float v1, float v2, float v3, float v4, float v5)
  91{
  92        return dcn_bw_max3(v1, v2, v3) > dcn_bw_max2(v4, v5) ? dcn_bw_max3(v1, v2, v3) : dcn_bw_max2(v4, v5);
  93}
  94
  95float dcn_bw_pow(float a, float exp)
  96{
  97        float temp;
  98        /*ASSERT(exp == (int)exp);*/
  99        if ((int)exp == 0)
 100                return 1;
 101        temp = dcn_bw_pow(a, (int)(exp / 2));
 102        if (((int)exp % 2) == 0) {
 103                return temp * temp;
 104        } else {
 105                if ((int)exp > 0)
 106                        return a * temp * temp;
 107                else
 108                        return (temp * temp) / a;
 109        }
 110}
 111
 112float dcn_bw_log(float a, float b)
 113{
 114        int * const exp_ptr = (int *)(&a);
 115        int x = *exp_ptr;
 116        const int log_2 = ((x >> 23) & 255) - 128;
 117        x &= ~(255 << 23);
 118        x += 127 << 23;
 119        *exp_ptr = x;
 120
 121        a = ((-1.0f / 3) * a + 2) * a - 2.0f / 3;
 122
 123        if (b > 2.00001 || b < 1.99999)
 124                return (a + log_2) / dcn_bw_log(b, 2);
 125        else
 126                return (a + log_2);
 127}
 128