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#endif
 37
 38/**
 39 * DOC: DC FPU manipulation overview
 40 *
 41 * DC core uses FPU operations in multiple parts of the code, which requires a
 42 * more specialized way to manage these areas' entrance. To fulfill this
 43 * requirement, we created some wrapper functions that encapsulate
 44 * kernel_fpu_begin/end to better fit our need in the display component. In
 45 * summary, in this file, you can find functions related to FPU operation
 46 * management.
 47 */
 48
 49static DEFINE_PER_CPU(int, fpu_recursion_depth);
 50
 51/**
 52 * dc_assert_fp_enabled - Check if FPU protection is enabled
 53 *
 54 * This function tells if the code is already under FPU protection or not. A
 55 * function that works as an API for a set of FPU operations can use this
 56 * function for checking if the caller invoked it after DC_FP_START(). For
 57 * example, take a look at dcn20_fpu.c file.
 58 */
 59inline void dc_assert_fp_enabled(void)
 60{
 61	int *pcpu, depth = 0;
 62
 63	pcpu = get_cpu_ptr(&fpu_recursion_depth);
 64	depth = *pcpu;
 65	put_cpu_ptr(&fpu_recursion_depth);
 66
 67	ASSERT(depth >= 1);
 68}
 69
 70/**
 71 * dc_fpu_begin - Enables FPU protection
 72 * @function_name: A string containing the function name for debug purposes
 73 *   (usually __func__)
 74 *
 75 * @line: A line number where DC_FP_START was invoked for debug purpose
 76 *   (usually __LINE__)
 77 *
 78 * This function is responsible for managing the use of kernel_fpu_begin() with
 79 * the advantage of providing an event trace for debugging.
 80 *
 81 * Note: Do not call this function directly; always use DC_FP_START().
 82 */
 83void dc_fpu_begin(const char *function_name, const int line)
 84{
 85	int *pcpu;
 86
 87	pcpu = get_cpu_ptr(&fpu_recursion_depth);
 88	*pcpu += 1;
 89
 90	if (*pcpu == 1) {
 91#if defined(CONFIG_X86)
 92		kernel_fpu_begin();
 93#elif defined(CONFIG_PPC64)
 94		if (cpu_has_feature(CPU_FTR_VSX_COMP)) {
 95			preempt_disable();
 96			enable_kernel_vsx();
 97		} else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) {
 98			preempt_disable();
 99			enable_kernel_altivec();
100		} else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) {
101			preempt_disable();
102			enable_kernel_fp();
103		}
104#elif defined(CONFIG_ARM64)
105		kernel_neon_begin();
106#endif
107	}
108
109	TRACE_DCN_FPU(true, function_name, line, *pcpu);
110	put_cpu_ptr(&fpu_recursion_depth);
111}
112
113/**
114 * dc_fpu_end - Disable FPU protection
115 * @function_name: A string containing the function name for debug purposes
116 * @line: A-line number where DC_FP_END was invoked for debug purpose
117 *
118 * This function is responsible for managing the use of kernel_fpu_end() with
119 * the advantage of providing an event trace for debugging.
120 *
121 * Note: Do not call this function directly; always use DC_FP_END().
122 */
123void dc_fpu_end(const char *function_name, const int line)
124{
125	int *pcpu;
126
127	pcpu = get_cpu_ptr(&fpu_recursion_depth);
128	*pcpu -= 1;
129	if (*pcpu <= 0) {
130#if defined(CONFIG_X86)
131		kernel_fpu_end();
132#elif defined(CONFIG_PPC64)
133		if (cpu_has_feature(CPU_FTR_VSX_COMP)) {
134			disable_kernel_vsx();
135			preempt_enable();
136		} else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) {
137			disable_kernel_altivec();
138			preempt_enable();
139		} else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) {
140			disable_kernel_fp();
141			preempt_enable();
142		}
143#elif defined(CONFIG_ARM64)
144		kernel_neon_end();
145#endif
146	}
147
148	TRACE_DCN_FPU(false, function_name, line, *pcpu);
149	put_cpu_ptr(&fpu_recursion_depth);
150}