drm/amd/display: add functionality to get pipe CRC source.

[Why]
We need to check the pipe crc source through debugfs for bypass mode test.

[How]
add implementation of amdgpu_dm_crtc_get_crc_sources and hook into drm_crtc
callback get_crc_sources.
Signed-off-by: Dingchen Zhang <dingchen.zhang@amd.com>
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -3735,6 +3735,7 @@ static const struct drm_crtc_funcs amdgpu_dm_crtc_funcs = {
 	.atomic_destroy_state = dm_crtc_destroy_state,
 	.set_crc_source = amdgpu_dm_crtc_set_crc_source,
 	.verify_crc_source = amdgpu_dm_crtc_verify_crc_source,
+	.get_crc_sources = amdgpu_dm_crtc_get_crc_sources,
 	.enable_vblank = dm_enable_vblank,
 	.disable_vblank = dm_disable_vblank,
 };

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

@@ -30,6 +30,13 @@
 #include "amdgpu_dm.h"
 #include "dc.h"
 
+static const char *const pipe_crc_sources[] = {
+	"none",
+	"crtc",
+	"dprx",
+	"auto",
+};
+
 static enum amdgpu_dm_pipe_crc_source dm_parse_crc_source(const char *source)
 {
 	if (!source || !strcmp(source, "none"))
@@ -42,6 +49,13 @@ static enum amdgpu_dm_pipe_crc_source dm_parse_crc_source(const char *source)
 	return AMDGPU_DM_PIPE_CRC_SOURCE_INVALID;
 }
 
+const char *const *amdgpu_dm_crtc_get_crc_sources(struct drm_crtc *crtc,
+						  size_t *count)
+{
+	*count = ARRAY_SIZE(pipe_crc_sources);
+	return pipe_crc_sources;
+}
+
 int
 amdgpu_dm_crtc_verify_crc_source(struct drm_crtc *crtc, const char *src_name,
 				 size_t *values_cnt)

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.h

@@ -46,10 +46,13 @@ int amdgpu_dm_crtc_set_crc_source(struct drm_crtc *crtc, const char *src_name);
 int amdgpu_dm_crtc_verify_crc_source(struct drm_crtc *crtc,
 				     const char *src_name,
 				     size_t *values_cnt);
+const char *const *amdgpu_dm_crtc_get_crc_sources(struct drm_crtc *crtc,
+						  size_t *count);
 void amdgpu_dm_crtc_handle_crc_irq(struct drm_crtc *crtc);
 #else
 #define amdgpu_dm_crtc_set_crc_source NULL
 #define amdgpu_dm_crtc_verify_crc_source NULL
+#define amdgpu_dm_crtc_get_crc_sources NULL
 #define amdgpu_dm_crtc_handle_crc_irq(x)
 #endif