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1// SPDX-License-Identifier: MIT2/*3 * Copyright 2021 Advanced Micro Devices, Inc.4 *5 * Permission is hereby granted, free of charge, to any person obtaining a6 * copy of this software and associated documentation files (the "Software"),7 * to deal in the Software without restriction, including without limitation8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,9 * and/or sell copies of the Software, and to permit persons to whom the10 * Software is furnished to do so, subject to the following conditions:11 *12 * The above copyright notice and this permission notice shall be included in13 * all copies or substantial portions of the Software.14 *15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL18 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR19 * 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 OR21 * OTHER DEALINGS IN THE SOFTWARE.22 *23 * Authors: AMD24 *25 */26 27#include "dc_trace.h"28 29#include <linux/fpu.h>30 31/**32 * DOC: DC FPU manipulation overview33 *34 * DC core uses FPU operations in multiple parts of the code, which requires a35 * more specialized way to manage these areas' entrance. To fulfill this36 * requirement, we created some wrapper functions that encapsulate37 * kernel_fpu_begin/end to better fit our need in the display component. In38 * summary, in this file, you can find functions related to FPU operation39 * management.40 */41 42static DEFINE_PER_CPU(int, fpu_recursion_depth);43 44/**45 * dc_assert_fp_enabled - Check if FPU protection is enabled46 *47 * This function tells if the code is already under FPU protection or not. A48 * function that works as an API for a set of FPU operations can use this49 * function for checking if the caller invoked it after DC_FP_START(). For50 * example, take a look at dcn20_fpu.c file.51 */52inline void dc_assert_fp_enabled(void)53{54 int depth;55 56 depth = __this_cpu_read(fpu_recursion_depth);57 58 ASSERT(depth >= 1);59}60 61/**62 * dc_fpu_begin - Enables FPU protection63 * @function_name: A string containing the function name for debug purposes64 * (usually __func__)65 *66 * @line: A line number where DC_FP_START was invoked for debug purpose67 * (usually __LINE__)68 *69 * This function is responsible for managing the use of kernel_fpu_begin() with70 * the advantage of providing an event trace for debugging.71 *72 * Note: Do not call this function directly; always use DC_FP_START().73 */74void dc_fpu_begin(const char *function_name, const int line)75{76 int depth;77 78 WARN_ON_ONCE(!in_task());79 preempt_disable();80 depth = __this_cpu_inc_return(fpu_recursion_depth);81 if (depth == 1) {82 BUG_ON(!kernel_fpu_available());83 kernel_fpu_begin();84 }85 86 TRACE_DCN_FPU(true, function_name, line, depth);87}88 89/**90 * dc_fpu_end - Disable FPU protection91 * @function_name: A string containing the function name for debug purposes92 * @line: A-line number where DC_FP_END was invoked for debug purpose93 *94 * This function is responsible for managing the use of kernel_fpu_end() with95 * the advantage of providing an event trace for debugging.96 *97 * Note: Do not call this function directly; always use DC_FP_END().98 */99void dc_fpu_end(const char *function_name, const int line)100{101 int depth;102 103 depth = __this_cpu_dec_return(fpu_recursion_depth);104 if (depth == 0) {105 kernel_fpu_end();106 } else {107 WARN_ON_ONCE(depth < 0);108 }109 110 TRACE_DCN_FPU(false, function_name, line, depth);111 preempt_enable();112}113