display/amdgpu_dm/dc_fpu.c

0001 // SPDX-License-Identifier: MIT
0002 /*
0003  * Copyright 2021 Advanced Micro Devices, Inc.
0004  *
0005  * Permission is hereby granted, free of charge, to any person obtaining a
0006  * copy of this software and associated documentation files (the "Software"),
0007  * to deal in the Software without restriction, including without limitation
0008  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
0009  * and/or sell copies of the Software, and to permit persons to whom the
0010  * Software is furnished to do so, subject to the following conditions:
0011  *
0012  * The above copyright notice and this permission notice shall be included in
0013  * all copies or substantial portions of the Software.
0014  *
0015  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
0016  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
0017  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
0018  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
0019  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
0020  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
0021  * OTHER DEALINGS IN THE SOFTWARE.
0022  *
0023  * Authors: AMD
0024  *
0025  */
0026
0027 #include "dc_trace.h"
0028
0029 #if defined(CONFIG_X86)
0030 #include <asm/fpu/api.h>
0031 #elif defined(CONFIG_PPC64)
0032 #include <asm/switch_to.h>
0033 #include <asm/cputable.h>
0034 #endif
0035
0036 /**
0037  * DOC: DC FPU manipulation overview
0038  *
0039  * DC core uses FPU operations in multiple parts of the code, which requires a
0040  * more specialized way to manage these areas' entrance. To fulfill this
0041  * requirement, we created some wrapper functions that encapsulate
0042  * kernel_fpu_begin/end to better fit our need in the display component. In
0043  * summary, in this file, you can find functions related to FPU operation
0044  * management.
0045  */
0046
0047 static DEFINE_PER_CPU(int, fpu_recursion_depth);
0048
0049 /**
0050  * dc_assert_fp_enabled - Check if FPU protection is enabled
0051  *
0052  * This function tells if the code is already under FPU protection or not. A
0053  * function that works as an API for a set of FPU operations can use this
0054  * function for checking if the caller invoked it after DC_FP_START(). For
0055  * example, take a look at dcn20_fpu.c file.
0056  */
0057 inline void dc_assert_fp_enabled(void)
0058 {
0059     int *pcpu, depth = 0;
0060
0061     pcpu = get_cpu_ptr(&fpu_recursion_depth);
0062     depth = *pcpu;
0063     put_cpu_ptr(&fpu_recursion_depth);
0064
0065     ASSERT(depth >= 1);
0066 }
0067
0068 /**
0069  * dc_fpu_begin - Enables FPU protection
0070  * @function_name: A string containing the function name for debug purposes
0071  *   (usually __func__)
0072  *
0073  * @line: A line number where DC_FP_START was invoked for debug purpose
0074  *   (usually __LINE__)
0075  *
0076  * This function is responsible for managing the use of kernel_fpu_begin() with
0077  * the advantage of providing an event trace for debugging.
0078  *
0079  * Note: Do not call this function directly; always use DC_FP_START().
0080  */
0081 void dc_fpu_begin(const char *function_name, const int line)
0082 {
0083     int *pcpu;
0084
0085     pcpu = get_cpu_ptr(&fpu_recursion_depth);
0086     *pcpu += 1;
0087
0088     if (*pcpu == 1) {
0089 #if defined(CONFIG_X86)
0090         kernel_fpu_begin();
0091 #elif defined(CONFIG_PPC64)
0092         if (cpu_has_feature(CPU_FTR_VSX_COMP)) {
0093             preempt_disable();
0094             enable_kernel_vsx();
0095         } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) {
0096             preempt_disable();
0097             enable_kernel_altivec();
0098         } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) {
0099             preempt_disable();
0100             enable_kernel_fp();
0101         }
0102 #endif
0103     }
0104
0105     TRACE_DCN_FPU(true, function_name, line, *pcpu);
0106     put_cpu_ptr(&fpu_recursion_depth);
0107 }
0108
0109 /**
0110  * dc_fpu_end - Disable FPU protection
0111  * @function_name: A string containing the function name for debug purposes
0112  * @line: A-line number where DC_FP_END was invoked for debug purpose
0113  *
0114  * This function is responsible for managing the use of kernel_fpu_end() with
0115  * the advantage of providing an event trace for debugging.
0116  *
0117  * Note: Do not call this function directly; always use DC_FP_END().
0118  */
0119 void dc_fpu_end(const char *function_name, const int line)
0120 {
0121     int *pcpu;
0122
0123     pcpu = get_cpu_ptr(&fpu_recursion_depth);
0124     *pcpu -= 1;
0125     if (*pcpu <= 0) {
0126 #if defined(CONFIG_X86)
0127         kernel_fpu_end();
0128 #elif defined(CONFIG_PPC64)
0129         if (cpu_has_feature(CPU_FTR_VSX_COMP)) {
0130             disable_kernel_vsx();
0131             preempt_enable();
0132         } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) {
0133             disable_kernel_altivec();
0134             preempt_enable();
0135         } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) {
0136             disable_kernel_fp();
0137             preempt_enable();
0138         }
0139 #endif
0140     }
0141
0142     TRACE_DCN_FPU(false, function_name, line, *pcpu);
0143     put_cpu_ptr(&fpu_recursion_depth);
0144 }