drm/amd/display: Support DRM_AMD_DC_FP on RISC-V

RISC-V uses kernel_fpu_begin()/kernel_fpu_end() like several other architectures. Enabling hardware FP requires overriding the ISA string for the relevant compilation units. Signed-off-by: Samuel Holland <[email protected]> Signed-off-by: Icenowy Zheng <[email protected]> Signed-off-by: Han Gao <[email protected]>
Avenger-285714 · Sep 13, 2024 · 15557da · 15557da
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commit 15557da
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Showing 3 changed files with 11 additions and 2 deletions.
diff --git a/drivers/gpu/drm/amd/display/Kconfig b/drivers/gpu/drm/amd/display/Kconfig
@@ -9,6 +9,7 @@ config DRM_AMD_DC
 	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 || LOONGARCH || (PPC64 && ALTIVEC) || (ARM64 && KERNEL_MODE_NEON && !CC_IS_CLANG))
+	select DRM_AMD_DC_DCN if RISCV && FPU
 	help
 	  Choose this option if you want to use the new display engine
 	  support for AMDGPU. This adds required support for Vega and

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c
@@ -35,6 +35,8 @@
 #include <asm/neon.h>
 #elif defined(CONFIG_LOONGARCH)
 #include <asm/fpu.h>
+#elif defined(CONFIG_RISCV)
+#include <asm/switch_to.h>
 #endif
 
 /**
@@ -90,7 +92,7 @@ void dc_fpu_begin(const char *function_name, const int line)
 	*pcpu += 1;
 
 	if (*pcpu == 1) {
-#if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH)
+#if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH) || defined(CONFIG_RISCV)
 		migrate_disable();
 		kernel_fpu_begin();
 #elif defined(CONFIG_PPC64)
@@ -130,7 +132,7 @@ 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) || defined(CONFIG_LOONGARCH)
+#if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH) || defined(CONFIG_RISCV)
 		kernel_fpu_end();
 		migrate_enable();
 #elif defined(CONFIG_PPC64)

diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile
@@ -43,6 +43,12 @@ dml_ccflags := -mfpu=64
 dml_rcflags := -msoft-float
 endif
 
+ifdef CONFIG_RISCV
+include $(srctree)/arch/riscv/Makefile.isa
+# Remove V from the ISA string, like in arch/riscv/Makefile, but keep F and D.
+dml_ccflags := -march=$(subst v,,$(riscv-march-y))
+endif
+
 ifdef CONFIG_CC_IS_GCC
 ifneq ($(call gcc-min-version, 70100),y)
 IS_OLD_GCC = 1