xref: /linux/drivers/gpu/drm/amd/display/dc/basics/conversion.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
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 
35 uint16_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 		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 			dc_fixpt_mul_int(
52 				arg,
53 				divisor));
54 	else {
55 		numerator = dc_fixpt_floor(
56 			dc_fixpt_sub(
57 				dc_fixpt_from_int(
58 					1LL << integer_bits),
59 				dc_fixpt_recip(
60 					dc_fixpt_from_int(
61 						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 		arg, 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  */
79 void 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 					dc_fixpt_clamp(
94 						flt[i],
95 						min_2_13,
96 						max_2_13),
97 						2,
98 						13);
99 
100 		matrix[i] = (uint16_t)reg_value;
101 	}
102 }
103 
104 static 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(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  */
130 void 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(reg[i], 2, 13);
136 }
137 
138 static 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 
150 void 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(num, den);
156 	*out_num = num / gcd;
157 	*out_den = den / gcd;
158 }
159