1 /* $NetBSD: amdgpu_bw_fixed.c,v 1.2 2021/12/18 23:45:01 riastradh Exp $ */
2
3 /*
4 * Copyright 2015 Advanced Micro Devices, Inc.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
20 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
21 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
22 * OTHER DEALINGS IN THE SOFTWARE.
23 *
24 * Authors: AMD
25 *
26 */
27 #include <sys/cdefs.h>
28 __KERNEL_RCSID(0, "$NetBSD: amdgpu_bw_fixed.c,v 1.2 2021/12/18 23:45:01 riastradh Exp $");
29
30 #include "dm_services.h"
31 #include "bw_fixed.h"
32
33
34 #define MIN_I64 \
35 (int64_t)(-(1LL << 63))
36
37 #define MAX_I64 \
38 (int64_t)((1ULL << 63) - 1)
39
40 #define FRACTIONAL_PART_MASK \
41 ((1ULL << BW_FIXED_BITS_PER_FRACTIONAL_PART) - 1)
42
43 #define GET_FRACTIONAL_PART(x) \
44 (FRACTIONAL_PART_MASK & (x))
45
abs_i64(int64_t arg)46 static uint64_t abs_i64(int64_t arg)
47 {
48 if (arg >= 0)
49 return (uint64_t)(arg);
50 else
51 return (uint64_t)(-arg);
52 }
53
bw_int_to_fixed_nonconst(int64_t value)54 struct bw_fixed bw_int_to_fixed_nonconst(int64_t value)
55 {
56 struct bw_fixed res;
57 ASSERT(value < BW_FIXED_MAX_I32 && value > BW_FIXED_MIN_I32);
58 res.value = value << BW_FIXED_BITS_PER_FRACTIONAL_PART;
59 return res;
60 }
61
bw_frc_to_fixed(int64_t numerator,int64_t denominator)62 struct bw_fixed bw_frc_to_fixed(int64_t numerator, int64_t denominator)
63 {
64 struct bw_fixed res;
65 bool arg1_negative = numerator < 0;
66 bool arg2_negative = denominator < 0;
67 uint64_t arg1_value;
68 uint64_t arg2_value;
69 uint64_t remainder;
70
71 /* determine integer part */
72 uint64_t res_value;
73
74 ASSERT(denominator != 0);
75
76 arg1_value = abs_i64(numerator);
77 arg2_value = abs_i64(denominator);
78 res_value = div64_u64_rem(arg1_value, arg2_value, &remainder);
79
80 ASSERT(res_value <= BW_FIXED_MAX_I32);
81
82 /* determine fractional part */
83 {
84 uint32_t i = BW_FIXED_BITS_PER_FRACTIONAL_PART;
85
86 do
87 {
88 remainder <<= 1;
89
90 res_value <<= 1;
91
92 if (remainder >= arg2_value)
93 {
94 res_value |= 1;
95 remainder -= arg2_value;
96 }
97 } while (--i != 0);
98 }
99
100 /* round up LSB */
101 {
102 uint64_t summand = (remainder << 1) >= arg2_value;
103
104 ASSERT(res_value <= MAX_I64 - summand);
105
106 res_value += summand;
107 }
108
109 res.value = (int64_t)(res_value);
110
111 if (arg1_negative ^ arg2_negative)
112 res.value = -res.value;
113 return res;
114 }
115
bw_floor2(const struct bw_fixed arg,const struct bw_fixed significance)116 struct bw_fixed bw_floor2(
117 const struct bw_fixed arg,
118 const struct bw_fixed significance)
119 {
120 struct bw_fixed result;
121 int64_t multiplicand;
122
123 multiplicand = div64_s64(arg.value, abs_i64(significance.value));
124 result.value = abs_i64(significance.value) * multiplicand;
125 ASSERT(abs_i64(result.value) <= abs_i64(arg.value));
126 return result;
127 }
128
bw_ceil2(const struct bw_fixed arg,const struct bw_fixed significance)129 struct bw_fixed bw_ceil2(
130 const struct bw_fixed arg,
131 const struct bw_fixed significance)
132 {
133 struct bw_fixed result;
134 int64_t multiplicand;
135
136 multiplicand = div64_s64(arg.value, abs_i64(significance.value));
137 result.value = abs_i64(significance.value) * multiplicand;
138 if (abs_i64(result.value) < abs_i64(arg.value)) {
139 if (arg.value < 0)
140 result.value -= abs_i64(significance.value);
141 else
142 result.value += abs_i64(significance.value);
143 }
144 return result;
145 }
146
bw_mul(const struct bw_fixed arg1,const struct bw_fixed arg2)147 struct bw_fixed bw_mul(const struct bw_fixed arg1, const struct bw_fixed arg2)
148 {
149 struct bw_fixed res;
150
151 bool arg1_negative = arg1.value < 0;
152 bool arg2_negative = arg2.value < 0;
153
154 uint64_t arg1_value = abs_i64(arg1.value);
155 uint64_t arg2_value = abs_i64(arg2.value);
156
157 uint64_t arg1_int = BW_FIXED_GET_INTEGER_PART(arg1_value);
158 uint64_t arg2_int = BW_FIXED_GET_INTEGER_PART(arg2_value);
159
160 uint64_t arg1_fra = GET_FRACTIONAL_PART(arg1_value);
161 uint64_t arg2_fra = GET_FRACTIONAL_PART(arg2_value);
162
163 uint64_t tmp;
164
165 res.value = arg1_int * arg2_int;
166
167 ASSERT(res.value <= BW_FIXED_MAX_I32);
168
169 res.value <<= BW_FIXED_BITS_PER_FRACTIONAL_PART;
170
171 tmp = arg1_int * arg2_fra;
172
173 ASSERT(tmp <= (uint64_t)(MAX_I64 - res.value));
174
175 res.value += tmp;
176
177 tmp = arg2_int * arg1_fra;
178
179 ASSERT(tmp <= (uint64_t)(MAX_I64 - res.value));
180
181 res.value += tmp;
182
183 tmp = arg1_fra * arg2_fra;
184
185 tmp = (tmp >> BW_FIXED_BITS_PER_FRACTIONAL_PART) +
186 (tmp >= (uint64_t)(bw_frc_to_fixed(1, 2).value));
187
188 ASSERT(tmp <= (uint64_t)(MAX_I64 - res.value));
189
190 res.value += tmp;
191
192 if (arg1_negative ^ arg2_negative)
193 res.value = -res.value;
194 return res;
195 }
196
197