drm/sun4i: abstract a engine type

As we are going to add support for the Allwinner DE2 engine in sun4i-drm
driver, we will finally have two types of display engines -- the DE1
backend and the DE2 mixer. They both do some display blending and feed
graphics data to TCON, and is part of the "Display Engine" called by
Allwinner, so I choose to call them both "engine" here.

Abstract the engine type to a new struct with an ops struct, which contains
functions that should be called outside the engine-specified code (in
TCON, CRTC or TV Encoder code).

In order to preserve bisectability, we also switch the backend and layer
code in its own module.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

1 files changed, 98 insertions, 0 deletions

diff --git a/drivers/gpu/drm/sun4i/sunxi_engine.h b/drivers/gpu/drm/sun4i/sunxi_engine.h
new file mode 100644
index 0000000..4cb70ae
--- /dev/null
+++ b/drivers/gpu/drm/sun4i/sunxi_engine.h
@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2017 Icenowy Zheng <icenowy@aosc.io>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ */
+
+#ifndef _SUNXI_ENGINE_H_
+#define _SUNXI_ENGINE_H_
+
+struct drm_plane;
+struct drm_device;
+
+struct sunxi_engine;
+
+struct sunxi_engine_ops {
+	void (*commit)(struct sunxi_engine *engine);
+	struct drm_plane **(*layers_init)(struct drm_device *drm,
+					  struct sunxi_engine *engine);
+
+	void (*apply_color_correction)(struct sunxi_engine *engine);
+	void (*disable_color_correction)(struct sunxi_engine *engine);
+};
+
+/**
+ * struct sunxi_engine - the common parts of an engine for sun4i-drm driver
+ * @ops:	the operations of the engine
+ * @node:	the of device node of the engine
+ * @regs:	the regmap of the engine
+ * @id:		the id of the engine (-1 if not used)
+ */
+struct sunxi_engine {
+	const struct sunxi_engine_ops	*ops;
+
+	struct device_node		*node;
+	struct regmap			*regs;
+
+	int id;
+
+	/* Engine list management */
+	struct list_head		list;
+};
+
+/**
+ * sunxi_engine_commit() - commit all changes of the engine
+ * @engine:	pointer to the engine
+ */
+static inline void
+sunxi_engine_commit(struct sunxi_engine *engine)
+{
+	if (engine->ops && engine->ops->commit)
+		engine->ops->commit(engine);
+}
+
+/**
+ * sunxi_engine_layers_init() - Create planes (layers) for the engine
+ * @drm:	pointer to the drm_device for which planes will be created
+ * @engine:	pointer to the engine
+ */
+static inline struct drm_plane **
+sunxi_engine_layers_init(struct drm_device *drm, struct sunxi_engine *engine)
+{
+	if (engine->ops && engine->ops->layers_init)
+		return engine->ops->layers_init(drm, engine);
+	return ERR_PTR(-ENOSYS);
+}
+
+/**
+ * sunxi_engine_apply_color_correction - Apply the RGB2YUV color correction
+ * @engine:	pointer to the engine
+ *
+ * This functionality is optional for an engine, however, if the engine is
+ * intended to be used with TV Encoder, the output will be incorrect
+ * without the color correction, due to TV Encoder expects the engine to
+ * output directly YUV signal.
+ */
+static inline void
+sunxi_engine_apply_color_correction(struct sunxi_engine *engine)
+{
+	if (engine->ops && engine->ops->apply_color_correction)
+		engine->ops->apply_color_correction(engine);
+}
+
+/**
+ * sunxi_engine_disable_color_correction - Disable the color space correction
+ * @engine:	pointer to the engine
+ *
+ * This function is paired with apply_color_correction().
+ */
+static inline void
+sunxi_engine_disable_color_correction(struct sunxi_engine *engine)
+{
+	if (engine->ops && engine->ops->disable_color_correction)
+		engine->ops->disable_color_correction(engine);
+}
+#endif /* _SUNXI_ENGINE_H_ */