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 #endif
35
36 /**
37 * DOC: DC FPU manipulation overview
38 *
39 * DC core uses FPU operations in multiple parts of the code, which requires a
40 * more specialized way to manage these areas' entrance. To fulfill this
41 * requirement, we created some wrapper functions that encapsulate
42 * kernel_fpu_begin/end to better fit our need in the display component. In
43 * summary, in this file, you can find functions related to FPU operation
44 * management.
45 */
46
47 static DEFINE_PER_CPU(int, fpu_recursion_depth);
48
49 /**
50 * dc_assert_fp_enabled - Check if FPU protection is enabled
51 *
52 * This function tells if the code is already under FPU protection or not. A
53 * function that works as an API for a set of FPU operations can use this
54 * function for checking if the caller invoked it after DC_FP_START(). For
55 * example, take a look at dcn20_fpu.c file.
56 */
dc_assert_fp_enabled(void)57 inline void dc_assert_fp_enabled(void)
58 {
59 int *pcpu, depth = 0;
60
61 pcpu = get_cpu_ptr(&fpu_recursion_depth);
62 depth = *pcpu;
63 put_cpu_ptr(&fpu_recursion_depth);
64
65 ASSERT(depth >= 1);
66 }
67
68 /**
69 * dc_fpu_begin - Enables FPU protection
70 * @function_name: A string containing the function name for debug purposes
71 * (usually __func__)
72 *
73 * @line: A line number where DC_FP_START was invoked for debug purpose
74 * (usually __LINE__)
75 *
76 * This function is responsible for managing the use of kernel_fpu_begin() with
77 * the advantage of providing an event trace for debugging.
78 *
79 * Note: Do not call this function directly; always use DC_FP_START().
80 */
dc_fpu_begin(const char * function_name,const int line)81 void dc_fpu_begin(const char *function_name, const int line)
82 {
83 int *pcpu;
84
85 pcpu = get_cpu_ptr(&fpu_recursion_depth);
86 *pcpu += 1;
87
88 if (*pcpu == 1) {
89 #if defined(CONFIG_X86)
90 kernel_fpu_begin();
91 #elif defined(CONFIG_PPC64)
92 if (cpu_has_feature(CPU_FTR_VSX_COMP)) {
93 preempt_disable();
94 enable_kernel_vsx();
95 } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) {
96 preempt_disable();
97 enable_kernel_altivec();
98 } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) {
99 preempt_disable();
100 enable_kernel_fp();
101 }
102 #endif
103 }
104
105 TRACE_DCN_FPU(true, function_name, line, *pcpu);
106 put_cpu_ptr(&fpu_recursion_depth);
107 }
108
109 /**
110 * dc_fpu_end - Disable FPU protection
111 * @function_name: A string containing the function name for debug purposes
112 * @line: A-line number where DC_FP_END was invoked for debug purpose
113 *
114 * This function is responsible for managing the use of kernel_fpu_end() with
115 * the advantage of providing an event trace for debugging.
116 *
117 * Note: Do not call this function directly; always use DC_FP_END().
118 */
dc_fpu_end(const char * function_name,const int line)119 void dc_fpu_end(const char *function_name, const int line)
120 {
121 int *pcpu;
122
123 pcpu = get_cpu_ptr(&fpu_recursion_depth);
124 *pcpu -= 1;
125 if (*pcpu <= 0) {
126 #if defined(CONFIG_X86)
127 kernel_fpu_end();
128 #elif defined(CONFIG_PPC64)
129 if (cpu_has_feature(CPU_FTR_VSX_COMP)) {
130 disable_kernel_vsx();
131 preempt_enable();
132 } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) {
133 disable_kernel_altivec();
134 preempt_enable();
135 } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) {
136 disable_kernel_fp();
137 preempt_enable();
138 }
139 #endif
140 }
141
142 TRACE_DCN_FPU(false, function_name, line, *pcpu);
143 put_cpu_ptr(&fpu_recursion_depth);
144 }
145