drm/komeda: Add writeback support

Komeda driver uses a individual component to describe the HW's writeback
caps, but drivers doesn't define a new structure and still uses the
existing "struct komeda_layer" to describe this new component.
The detailed changes as follow:

1. Initialize wb_layer according to HW and report it to CORE.
2. CORE exposes wb_layer as a resource to KMS by private_obj.
3. Report writeback supporting by add a wb_connector to KMS, and then
   wb_connector will take act as a component resources user,
   so the func komeda_wb_encoder_atomic_check claims komeda resources
   (scaler and wb_layer) accroding to its state configuration to the
   wb_connector. and the wb_state configuration will be validated on the
   specific component resources to see if the caps of component can
   meet the requirement of wb_connector. if not check failed.
4. Update irq_handler to notify the completion of writeback.

NOTE:
This change doesn't add scaling writeback support, that support will
be added in the future after the scaler support.

v2: Rebase
v3: Rebase and constify the d71_wb_layer_funcs
v4: Addressed Ayan's comments

Depends on:
- https://patchwork.freedesktop.org/series/59915/

Signed-off-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Acked-by: Ayan Kumar Halder <ayan.halder@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_private_obj.c b/drivers/gpu/drm/arm/display/komeda/komeda_private_obj.c
index a54878cbd6e4..d53bd6c23c5d 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_private_obj.c
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_private_obj.c
@@ -252,6 +252,12 @@ int komeda_kms_add_private_objs(struct komeda_kms_dev *kms,
 				return err;
 		}
 
+		if (pipe->wb_layer) {
+			err = komeda_layer_obj_add(kms, pipe->wb_layer);
+			if (err)
+				return err;
+		}
+
 		err = komeda_compiz_obj_add(kms, pipe->compiz);
 		if (err)
 			return err;