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 static DEFINE_PER_CPU(int, fpu_recursion_depth);
52
53 /**
54 * dc_assert_fp_enabled - Check if FPU protection is enabled
55 *
56 * This function tells if the code is already under FPU protection or not. A
57 * function that works as an API for a set of FPU operations can use this
58 * function for checking if the caller invoked it after DC_FP_START(). For
59 * example, take a look at dcn20_fpu.c file.
60 */
dc_assert_fp_enabled(void)61 inline void dc_assert_fp_enabled(void)
62 {
63 int *pcpu, depth = 0;
64
65 pcpu = get_cpu_ptr(&fpu_recursion_depth);
66 depth = *pcpu;
67 put_cpu_ptr(&fpu_recursion_depth);
68
69 ASSERT(depth >= 1);
70 }
71
72 /**
73 * dc_fpu_begin - Enables FPU protection
74 * @function_name: A string containing the function name for debug purposes
75 * (usually __func__)
76 *
77 * @line: A line number where DC_FP_START was invoked for debug purpose
78 * (usually __LINE__)
79 *
80 * This function is responsible for managing the use of kernel_fpu_begin() with
81 * the advantage of providing an event trace for debugging.
82 *
83 * Note: Do not call this function directly; always use DC_FP_START().
84 */
dc_fpu_begin(const char * function_name,const int line)85 void dc_fpu_begin(const char *function_name, const int line)
86 {
87 int *pcpu;
88
89 pcpu = get_cpu_ptr(&fpu_recursion_depth);
90 *pcpu += 1;
91
92 if (*pcpu == 1) {
93 #if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH)
94 migrate_disable();
95 kernel_fpu_begin();
96 #elif defined(CONFIG_PPC64)
97 if (cpu_has_feature(CPU_FTR_VSX_COMP)) {
98 preempt_disable();
99 enable_kernel_vsx();
100 } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) {
101 preempt_disable();
102 enable_kernel_altivec();
103 } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) {
104 preempt_disable();
105 enable_kernel_fp();
106 }
107 #elif defined(CONFIG_ARM64)
108 kernel_neon_begin();
109 #endif
110 }
111
112 TRACE_DCN_FPU(true, function_name, line, *pcpu);
113 put_cpu_ptr(&fpu_recursion_depth);
114 }
115
116 /**
117 * dc_fpu_end - Disable FPU protection
118 * @function_name: A string containing the function name for debug purposes
119 * @line: A-line number where DC_FP_END was invoked for debug purpose
120 *
121 * This function is responsible for managing the use of kernel_fpu_end() with
122 * the advantage of providing an event trace for debugging.
123 *
124 * Note: Do not call this function directly; always use DC_FP_END().
125 */
dc_fpu_end(const char * function_name,const int line)126 void dc_fpu_end(const char *function_name, const int line)
127 {
128 int *pcpu;
129
130 pcpu = get_cpu_ptr(&fpu_recursion_depth);
131 *pcpu -= 1;
132 if (*pcpu <= 0) {
133 #if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH)
134 kernel_fpu_end();
135 migrate_enable();
136 #elif defined(CONFIG_PPC64)
137 if (cpu_has_feature(CPU_FTR_VSX_COMP)) {
138 disable_kernel_vsx();
139 preempt_enable();
140 } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) {
141 disable_kernel_altivec();
142 preempt_enable();
143 } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) {
144 disable_kernel_fp();
145 preempt_enable();
146 }
147 #elif defined(CONFIG_ARM64)
148 kernel_neon_end();
149 #endif
150 }
151
152 TRACE_DCN_FPU(false, function_name, line, *pcpu);
153 put_cpu_ptr(&fpu_recursion_depth);
154 }
155