1/*
2 * Copyright 2012-15 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 "dm_services.h"
27#include "basics/conversion.h"
28
29#define DIVIDER 10000
30
31/* S2D13 value in [-3.00...0.9999] */
32#define S2D13_MIN (-3 * DIVIDER)
33#define S2D13_MAX (3 * DIVIDER)
34
35uint16_t fixed_point_to_int_frac(
36 struct fixed31_32 arg,
37 uint8_t integer_bits,
38 uint8_t fractional_bits)
39{
40 int32_t numerator;
41 int32_t divisor = 1 << fractional_bits;
42
43 uint16_t result;
44
45 uint16_t d = (uint16_t)dc_fixpt_floor(
46 arg: dc_fixpt_abs(
47 arg));
48
49 if (d <= (uint16_t)(1 << integer_bits) - (1 / (uint16_t)divisor))
50 numerator = (uint16_t)dc_fixpt_round(
51 arg: dc_fixpt_mul_int(
52 arg1: arg,
53 arg2: divisor));
54 else {
55 numerator = dc_fixpt_floor(
56 arg: dc_fixpt_sub(
57 arg1: dc_fixpt_from_int(
58 arg: 1LL << integer_bits),
59 arg2: dc_fixpt_recip(
60 arg: dc_fixpt_from_int(
61 arg: divisor))));
62 }
63
64 if (numerator >= 0)
65 result = (uint16_t)numerator;
66 else
67 result = (uint16_t)(
68 (1 << (integer_bits + fractional_bits + 1)) + numerator);
69
70 if ((result != 0) && dc_fixpt_lt(
71 arg1: arg, arg2: dc_fixpt_zero))
72 result |= 1 << (integer_bits + fractional_bits);
73
74 return result;
75}
76/*
77 * convert_float_matrix - This converts a double into HW register spec defined format S2D13.
78 */
79void convert_float_matrix(
80 uint16_t *matrix,
81 struct fixed31_32 *flt,
82 uint32_t buffer_size)
83{
84 const struct fixed31_32 min_2_13 =
85 dc_fixpt_from_fraction(S2D13_MIN, DIVIDER);
86 const struct fixed31_32 max_2_13 =
87 dc_fixpt_from_fraction(S2D13_MAX, DIVIDER);
88 uint32_t i;
89
90 for (i = 0; i < buffer_size; ++i) {
91 uint32_t reg_value =
92 fixed_point_to_int_frac(
93 arg: dc_fixpt_clamp(
94 arg: flt[i],
95 min_value: min_2_13,
96 max_value: max_2_13),
97 integer_bits: 2,
98 fractional_bits: 13);
99
100 matrix[i] = (uint16_t)reg_value;
101 }
102}
103
104static struct fixed31_32 int_frac_to_fixed_point(uint16_t arg,
105 uint8_t integer_bits,
106 uint8_t fractional_bits)
107{
108 struct fixed31_32 result;
109 uint16_t sign_mask = 1 << (fractional_bits + integer_bits);
110 uint16_t value_mask = sign_mask - 1;
111
112 result.value = (long long)(arg & value_mask) <<
113 (FIXED31_32_BITS_PER_FRACTIONAL_PART - fractional_bits);
114
115 if (arg & sign_mask)
116 result = dc_fixpt_neg(arg: result);
117
118 return result;
119}
120
121/**
122 * convert_hw_matrix - converts HW values into fixed31_32 matrix.
123 * @matrix: fixed point 31.32 matrix
124 * @reg: array of register values
125 * @buffer_size: size of the array of register values
126 *
127 * Converts HW register spec defined format S2D13 into a fixed-point 31.32
128 * matrix.
129 */
130void convert_hw_matrix(struct fixed31_32 *matrix,
131 uint16_t *reg,
132 uint32_t buffer_size)
133{
134 for (int i = 0; i < buffer_size; ++i)
135 matrix[i] = int_frac_to_fixed_point(arg: reg[i], integer_bits: 2, fractional_bits: 13);
136}
137
138static uint32_t find_gcd(uint32_t a, uint32_t b)
139{
140 uint32_t remainder;
141
142 while (b != 0) {
143 remainder = a % b;
144 a = b;
145 b = remainder;
146 }
147 return a;
148}
149
150void reduce_fraction(uint32_t num, uint32_t den,
151 uint32_t *out_num, uint32_t *out_den)
152{
153 uint32_t gcd = 0;
154
155 gcd = find_gcd(a: num, b: den);
156 *out_num = num / gcd;
157 *out_den = den / gcd;
158}
159

source code of linux/drivers/gpu/drm/amd/display/dc/basics/conversion.c