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 */ 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 */ 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 */ 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