[PATCH RFC 1/3] drm: Add drm_plane_add_modifiers()

[Tina Zhang <tina.zhang@xxxxxxxxx>]

Add a function to add modifiers to a plane.

Signed-off-by: Tina Zhang <tina.zhang@xxxxxxxxx>
---
 drivers/gpu/drm/drm_plane.c | 41 +++++++++++++++++++++++++++++++++++++
 include/drm/drm_plane.h     |  3 +++
 2 files changed, 44 insertions(+)

diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
index b570a480090a..793b16d84f86 100644
--- a/drivers/gpu/drm/drm_plane.c
+++ b/drivers/gpu/drm/drm_plane.c
@@ -288,6 +288,47 @@ int drm_universal_plane_init(struct drm_device *dev, struct drm_plane *plane,
 }
 EXPORT_SYMBOL(drm_universal_plane_init);
 
+int drm_plane_add_modifiers(struct drm_device *dev,
+				  struct drm_plane *plane,
+				  const uint64_t *format_modifiers)
+{
+	struct drm_mode_config *config = &dev->mode_config;
+	const uint64_t *temp_modifiers = format_modifiers;
+	unsigned int format_modifier_count = 0;
+
+	/*
+	 * Only considering adding modifiers when no modifier was
+	 * added to that plane before.
+	 */
+	if (!temp_modifiers || plane->modifier_count)
+		return -EINVAL;
+
+	while (*temp_modifiers++ != DRM_FORMAT_MOD_INVALID)
+		format_modifier_count++;
+
+	if (format_modifier_count)
+		config->allow_fb_modifiers = true;
+
+	plane->modifier_count = format_modifier_count;
+	plane->modifiers = kmalloc_array(format_modifier_count,
+					 sizeof(format_modifiers[0]),
+					 GFP_KERNEL);
+
+	if (format_modifier_count && !plane->modifiers) {
+		DRM_DEBUG_KMS("out of memory when allocating plane\n");
+		return -ENOMEM;
+	}
+
+	memcpy(plane->modifiers, format_modifiers,
+		   format_modifier_count * sizeof(format_modifiers[0]));
+	if (config->allow_fb_modifiers)
+		create_in_format_blob(dev, plane);
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_plane_add_modifiers);
+
+
 int drm_plane_register_all(struct drm_device *dev)
 {
 	unsigned int num_planes = 0;
diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h
index 50c23eb432b7..0dacdeffc3bc 100644
--- a/include/drm/drm_plane.h
+++ b/include/drm/drm_plane.h
@@ -827,6 +827,9 @@ int drm_universal_plane_init(struct drm_device *dev,
 			     const uint64_t *format_modifiers,
 			     enum drm_plane_type type,
 			     const char *name, ...);
+int drm_plane_add_modifiers(struct drm_device *dev,
+			       struct drm_plane *plane,
+			       const uint64_t *format_modifiers);
 int drm_plane_init(struct drm_device *dev,
 		   struct drm_plane *plane,
 		   uint32_t possible_crtcs,
-- 
2.25.1