drm/amdgpu_dm/crc: Implement verify_crc_source callback

This patch implements "verify_crc_source" callback function for
AMD drm driver.
Signed-off-by: Mahesh Kumar <mahesh1.kumar@intel.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180713135942.25061-5-mahesh1.kumar@intel.com

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

@@ -2563,6 +2563,7 @@ static const struct drm_crtc_funcs amdgpu_dm_crtc_funcs = {
 	.atomic_duplicate_state = dm_crtc_duplicate_state,
 	.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,
 	.enable_vblank = dm_enable_vblank,
 	.disable_vblank = dm_disable_vblank,
 };

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

@@ -260,9 +260,13 @@ amdgpu_dm_remove_sink_from_freesync_module(struct drm_connector *connector);
 #ifdef CONFIG_DEBUG_FS
 int amdgpu_dm_crtc_set_crc_source(struct drm_crtc *crtc, const char *src_name,
 				  size_t *values_cnt);
+int amdgpu_dm_crtc_verify_crc_source(struct drm_crtc *crtc,
+				     const char *src_name,
+				     size_t *values_cnt);
 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_handle_crc_irq(x)
 #endif
 

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

@@ -46,6 +46,22 @@ static enum amdgpu_dm_pipe_crc_source dm_parse_crc_source(const char *source)
 	return AMDGPU_DM_PIPE_CRC_SOURCE_INVALID;
 }
 
+int
+amdgpu_dm_crtc_verify_crc_source(struct drm_crtc *crtc, const char *src_name,
+				 size_t *values_cnt)
+{
+	enum amdgpu_dm_pipe_crc_source source = dm_parse_crc_source(src_name);
+
+	if (source < 0) {
+		DRM_DEBUG_DRIVER("Unknown CRC source %s for CRTC%d\n",
+				 src_name, crtc->index);
+		return -EINVAL;
+	}
+
+	*values_cnt = 3;
+	return 0;
+}
+
 int amdgpu_dm_crtc_set_crc_source(struct drm_crtc *crtc, const char *src_name,
 			   size_t *values_cnt)
 {