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, 19 insertions, 0 deletions

diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_framebuffer.c b/drivers/gpu/drm/arm/display/komeda/komeda_framebuffer.c
index 9cc9935024f7..4d8160cf09c3 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_framebuffer.c
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_framebuffer.c
@@ -165,3 +165,22 @@ komeda_fb_get_pixel_addr(struct komeda_fb *kfb, int x, int y, int plane)
 
 	return obj->paddr + offset;
 }
+
+/* if the fb can be supported by a specific layer */
+bool komeda_fb_is_layer_supported(struct komeda_fb *kfb, u32 layer_type)
+{
+	struct drm_framebuffer *fb = &kfb->base;
+	struct komeda_dev *mdev = fb->dev->dev_private;
+	const struct komeda_format_caps *caps;
+	u32 fourcc = fb->format->format;
+	u64 modifier = fb->modifier;
+
+	caps = komeda_get_format_caps(&mdev->fmt_tbl, fourcc, modifier);
+	if (!caps)
+		return false;
+
+	if (!(caps->supported_layer_types & layer_type))
+		return false;
+
+	return true;
+}