1 // SPDX-License-Identifier: MIT
2 /*
3 * Copyright 2021 Advanced Micro Devices, Inc.
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be included in
13 * all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
19 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
20 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
21 * OTHER DEALINGS IN THE SOFTWARE.
22 *
23 * Authors: AMD
24 *
25 */
26
27 #include "dc_trace.h"
28
29 #if defined(CONFIG_X86)
30 #include <asm/fpu/api.h>
31 #elif defined(CONFIG_PPC64)
32 #include <asm/switch_to.h>
33 #include <asm/cputable.h>
34 #elif defined(CONFIG_ARM64)
35 #include <asm/neon.h>
36 #elif defined(CONFIG_LOONGARCH)
37 #include <asm/fpu.h>
38 #endif
39
40 /**
41 * DOC: DC FPU manipulation overview
42 *
43 * DC core uses FPU operations in multiple parts of the code, which requires a
44 * more specialized way to manage these areas' entrance. To fulfill this
45 * requirement, we created some wrapper functions that encapsulate
46 * kernel_fpu_begin/end to better fit our need in the display component. In
47 * summary, in this file, you can find functions related to FPU operation
48 * management.
49 */
50
51 #ifdef notyet
52 static DEFINE_PER_CPU(int, fpu_recursion_depth);
53 #else
54 static int fpu_recursion_depth;
55
56 #define get_cpu_ptr(x) (x)
57 #define put_cpu_ptr(x) do {} while(0)
58 #endif
59
60 /**
61 * dc_assert_fp_enabled - Check if FPU protection is enabled
62 *
63 * This function tells if the code is already under FPU protection or not. A
64 * function that works as an API for a set of FPU operations can use this
65 * function for checking if the caller invoked it after DC_FP_START(). For
66 * example, take a look at dcn20_fpu.c file.
67 */
dc_assert_fp_enabled(void)68 void dc_assert_fp_enabled(void)
69 {
70 int *pcpu, depth = 0;
71
72 pcpu = get_cpu_ptr(&fpu_recursion_depth);
73 depth = *pcpu;
74 put_cpu_ptr(&fpu_recursion_depth);
75
76 ASSERT(depth >= 1);
77 }
78
79 /**
80 * dc_fpu_begin - Enables FPU protection
81 * @function_name: A string containing the function name for debug purposes
82 * (usually __func__)
83 *
84 * @line: A line number where DC_FP_START was invoked for debug purpose
85 * (usually __LINE__)
86 *
87 * This function is responsible for managing the use of kernel_fpu_begin() with
88 * the advantage of providing an event trace for debugging.
89 *
90 * Note: Do not call this function directly; always use DC_FP_START().
91 */
dc_fpu_begin(const char * function_name,const int line)92 void dc_fpu_begin(const char *function_name, const int line)
93 {
94 int *pcpu;
95
96 pcpu = get_cpu_ptr(&fpu_recursion_depth);
97 *pcpu += 1;
98
99 if (*pcpu == 1) {
100 #if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH)
101 migrate_disable();
102 kernel_fpu_begin();
103 #elif defined(CONFIG_PPC64)
104 if (cpu_has_feature(CPU_FTR_VSX_COMP)) {
105 preempt_disable();
106 enable_kernel_vsx();
107 } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) {
108 preempt_disable();
109 enable_kernel_altivec();
110 } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) {
111 preempt_disable();
112 enable_kernel_fp();
113 }
114 #elif defined(CONFIG_ARM64)
115 kernel_neon_begin();
116 #endif
117 }
118
119 TRACE_DCN_FPU(true, function_name, line, *pcpu);
120 put_cpu_ptr(&fpu_recursion_depth);
121 }
122
123 /**
124 * dc_fpu_end - Disable FPU protection
125 * @function_name: A string containing the function name for debug purposes
126 * @line: A-line number where DC_FP_END was invoked for debug purpose
127 *
128 * This function is responsible for managing the use of kernel_fpu_end() with
129 * the advantage of providing an event trace for debugging.
130 *
131 * Note: Do not call this function directly; always use DC_FP_END().
132 */
dc_fpu_end(const char * function_name,const int line)133 void dc_fpu_end(const char *function_name, const int line)
134 {
135 int *pcpu;
136
137 pcpu = get_cpu_ptr(&fpu_recursion_depth);
138 *pcpu -= 1;
139 if (*pcpu <= 0) {
140 #if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH)
141 kernel_fpu_end();
142 migrate_enable();
143 #elif defined(CONFIG_PPC64)
144 if (cpu_has_feature(CPU_FTR_VSX_COMP)) {
145 disable_kernel_vsx();
146 preempt_enable();
147 } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) {
148 disable_kernel_altivec();
149 preempt_enable();
150 } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) {
151 disable_kernel_fp();
152 preempt_enable();
153 }
154 #elif defined(CONFIG_ARM64)
155 kernel_neon_end();
156 #endif
157 }
158
159 TRACE_DCN_FPU(false, function_name, line, *pcpu);
160 put_cpu_ptr(&fpu_recursion_depth);
161 }
162