drm/amdgpu/display: Enable DC_FP for LoongArch

LoongArch now provides kernel_fpu_begin() and kernel_fpu_end() that are
used like the x86 counterparts in commit 2b3bd32e ("LoongArch:
Provide kernel fpu functions"), so we can enable DC_FP on LoongArch for
supporting more DCN devices.
Signed-off-by: WANG Xuerui <kernel@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/Kconfig

@@ -8,7 +8,7 @@ config DRM_AMD_DC
 	depends on BROKEN || !CC_IS_CLANG || X86_64 || SPARC64 || ARM64
 	select SND_HDA_COMPONENT if SND_HDA_CORE
 	# !CC_IS_CLANG: https://github.com/ClangBuiltLinux/linux/issues/1752
-	select DRM_AMD_DC_FP if (X86 || PPC64 || (ARM64 && KERNEL_MODE_NEON && !CC_IS_CLANG))
+	select DRM_AMD_DC_FP if (X86 || LOONGARCH || PPC64 || (ARM64 && KERNEL_MODE_NEON && !CC_IS_CLANG))
 	help
 	  Choose this option if you want to use the new display engine
 	  support for AMDGPU. This adds required support for Vega and

drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c

@@ -33,6 +33,8 @@
 #include <asm/cputable.h>
 #elif defined(CONFIG_ARM64)
 #include <asm/neon.h>
+#elif defined(CONFIG_LOONGARCH)
+#include <asm/fpu.h>
 #endif
 
 /**
@@ -88,7 +90,7 @@ void dc_fpu_begin(const char *function_name, const int line)
 	*pcpu += 1;
 
 	if (*pcpu == 1) {
-#if defined(CONFIG_X86)
+#if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH)
 		migrate_disable();
 		kernel_fpu_begin();
 #elif defined(CONFIG_PPC64)
@@ -128,7 +130,7 @@ void dc_fpu_end(const char *function_name, const int line)
 	pcpu = get_cpu_ptr(&fpu_recursion_depth);
 	*pcpu -= 1;
 	if (*pcpu <= 0) {
-#if defined(CONFIG_X86)
+#if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH)
 		kernel_fpu_end();
 		migrate_enable();
 #elif defined(CONFIG_PPC64)

drivers/gpu/drm/amd/display/dc/dml/Makefile

@@ -38,6 +38,11 @@ ifdef CONFIG_ARM64
 dml_rcflags := -mgeneral-regs-only
 endif
 
+ifdef CONFIG_LOONGARCH
+dml_ccflags := -mfpu=64
+dml_rcflags := -msoft-float
+endif
+
 ifdef CONFIG_CC_IS_GCC
 ifneq ($(call gcc-min-version, 70100),y)
 IS_OLD_GCC = 1