1 files changed, 112 insertions, 0 deletions
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c
new file mode 100644
index 000000000000..e46f8ce41d87
--- /dev/null
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright 2021 Advanced Micro Devices, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Authors: AMD
+ *
+ */
+
+#include "dc_trace.h"
+
+#include <linux/fpu.h>
+
+/**
+ * DOC: DC FPU manipulation overview
+ *
+ * DC core uses FPU operations in multiple parts of the code, which requires a
+ * more specialized way to manage these areas' entrance. To fulfill this
+ * requirement, we created some wrapper functions that encapsulate
+ * kernel_fpu_begin/end to better fit our need in the display component. In
+ * summary, in this file, you can find functions related to FPU operation
+ * management.
+ */
+
+static DEFINE_PER_CPU(int, fpu_recursion_depth);
+
+/**
+ * dc_assert_fp_enabled - Check if FPU protection is enabled
+ *
+ * This function tells if the code is already under FPU protection or not. A
+ * function that works as an API for a set of FPU operations can use this
+ * function for checking if the caller invoked it after DC_FP_START(). For
+ * example, take a look at dcn20_fpu.c file.
+ */
+inline void dc_assert_fp_enabled(void)
+{
+	int depth;
+
+	depth = __this_cpu_read(fpu_recursion_depth);
+
+	ASSERT(depth >= 1);
+}
+
+/**
+ * dc_fpu_begin - Enables FPU protection
+ * @function_name: A string containing the function name for debug purposes
+ *   (usually __func__)
+ *
+ * @line: A line number where DC_FP_START was invoked for debug purpose
+ *   (usually __LINE__)
+ *
+ * This function is responsible for managing the use of kernel_fpu_begin() with
+ * the advantage of providing an event trace for debugging.
+ *
+ * Note: Do not call this function directly; always use DC_FP_START().
+ */
+void dc_fpu_begin(const char *function_name, const int line)
+{
+	int depth;
+
+	WARN_ON_ONCE(!in_task());
+	preempt_disable();
+	depth = __this_cpu_inc_return(fpu_recursion_depth);
+	if (depth == 1) {
+		BUG_ON(!kernel_fpu_available());
+		kernel_fpu_begin();
+	}
+
+	TRACE_DCN_FPU(true, function_name, line, depth);
+}
+
+/**
+ * dc_fpu_end - Disable FPU protection
+ * @function_name: A string containing the function name for debug purposes
+ * @line: A-line number where DC_FP_END was invoked for debug purpose
+ *
+ * This function is responsible for managing the use of kernel_fpu_end() with
+ * the advantage of providing an event trace for debugging.
+ *
+ * Note: Do not call this function directly; always use DC_FP_END().
+ */
+void dc_fpu_end(const char *function_name, const int line)
+{
+	int depth;
+
+	depth = __this_cpu_dec_return(fpu_recursion_depth);
+	if (depth == 0) {
+		kernel_fpu_end();
+	} else {
+		WARN_ON_ONCE(depth < 0);
+	}
+
+	TRACE_DCN_FPU(false, function_name, line, depth);
+	preempt_enable();
+}