Create a subclass of drm_plane_state to store hardware-specific state
information (e.g. hardware plane format settings) in the future.

Signed-off-by: Icenowy Zheng <zhengxingda@iscas.ac.cn>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
---
Changes in v4:
- Add code clearing plane->state pointer after freeing it.
- Add Thomas's R-b.

Changes in v3:
- Switch to drm_WARN_ON().
- Stop to memdup the state.
- Move the code freeing the existing plane state to the branch checking
  whether it's not NULL.
- Rename the typecast function to `to_vs_plane_state()`.

Changes in v2:
- Add the #include clause for atomic state helpers, which was wrongly
  placed in the previous patch in v1.
- Switch to kzalloc_obj helper for allocating the state.

 drivers/gpu/drm/verisilicon/vs_plane.c        | 43 +++++++++++++++++++
 drivers/gpu/drm/verisilicon/vs_plane.h        | 14 ++++++
 .../gpu/drm/verisilicon/vs_primary_plane.c    |  6 +--
 3 files changed, 60 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/verisilicon/vs_plane.c b/drivers/gpu/drm/verisilicon/vs_plane.c
index fa88ed14e41d7..7c6b905c9e1fa 100644
--- a/drivers/gpu/drm/verisilicon/vs_plane.c
+++ b/drivers/gpu/drm/verisilicon/vs_plane.c
@@ -6,9 +6,11 @@
 #include <linux/errno.h>
 #include <linux/printk.h>
 
+#include <drm/drm_atomic_state_helper.h>
 #include <drm/drm_fb_dma_helper.h>
 #include <drm/drm_fourcc.h>
 #include <drm/drm_gem_dma_helper.h>
+#include <drm/drm_print.h>
 
 #include "vs_plane.h"
 
@@ -124,3 +126,44 @@ dma_addr_t vs_fb_get_dma_addr(struct drm_framebuffer *fb,
 
 	return dma_addr;
 }
+
+struct drm_plane_state *vs_plane_duplicate_state(struct drm_plane *plane)
+{
+	struct vs_plane_state *vs_state;
+
+	if (drm_WARN_ON(plane->dev, !plane->state))
+		return NULL;
+
+	vs_state = kzalloc_obj(*vs_state, GFP_KERNEL);
+	if (!vs_state)
+		return NULL;
+
+	__drm_atomic_helper_plane_duplicate_state(plane, &vs_state->base);
+
+	return &vs_state->base;
+}
+
+void vs_plane_destroy_state(struct drm_plane *plane,
+			    struct drm_plane_state *state)
+{
+	__drm_atomic_helper_plane_destroy_state(state);
+	kfree(state);
+}
+
+/* Called during init to allocate the plane's atomic state. */
+void vs_plane_reset(struct drm_plane *plane)
+{
+	struct vs_plane_state *vs_state;
+
+	if (plane->state) {
+		__drm_atomic_helper_plane_destroy_state(plane->state);
+		kfree(plane->state);
+		plane->state = NULL;
+	}
+
+	vs_state = kzalloc_obj(*vs_state, GFP_KERNEL);
+	if (!vs_state)
+		return;
+
+	__drm_atomic_helper_plane_reset(plane, &vs_state->base);
+}
diff --git a/drivers/gpu/drm/verisilicon/vs_plane.h b/drivers/gpu/drm/verisilicon/vs_plane.h
index a88cc19f2202e..48ed8fc754d18 100644
--- a/drivers/gpu/drm/verisilicon/vs_plane.h
+++ b/drivers/gpu/drm/verisilicon/vs_plane.h
@@ -63,10 +63,24 @@ struct vs_format {
 	bool uv_swizzle;
 };
 
+struct vs_plane_state {
+	struct drm_plane_state base;
+};
+
+static inline struct vs_plane_state *to_vs_plane_state(struct drm_plane_state *state)
+{
+	return container_of(state, struct vs_plane_state, base);
+}
+
 int drm_format_to_vs_format(u32 drm_format, struct vs_format *vs_format);
 dma_addr_t vs_fb_get_dma_addr(struct drm_framebuffer *fb,
 			      const struct drm_rect *src_rect);
 
+struct drm_plane_state *vs_plane_duplicate_state(struct drm_plane *plane);
+void vs_plane_destroy_state(struct drm_plane *plane,
+			    struct drm_plane_state *state);
+void vs_plane_reset(struct drm_plane *plane);
+
 struct drm_plane *vs_primary_plane_init(struct drm_device *dev, struct vs_dc *dc);
 
 #endif /* _VS_PLANE_H_ */
diff --git a/drivers/gpu/drm/verisilicon/vs_primary_plane.c b/drivers/gpu/drm/verisilicon/vs_primary_plane.c
index e8fcb5958615c..bad0bc5e3242d 100644
--- a/drivers/gpu/drm/verisilicon/vs_primary_plane.c
+++ b/drivers/gpu/drm/verisilicon/vs_primary_plane.c
@@ -145,10 +145,10 @@ static const struct drm_plane_helper_funcs vs_primary_plane_helper_funcs = {
 };
 
 static const struct drm_plane_funcs vs_primary_plane_funcs = {
-	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
-	.atomic_duplicate_state	= drm_atomic_helper_plane_duplicate_state,
+	.atomic_destroy_state	= vs_plane_destroy_state,
+	.atomic_duplicate_state	= vs_plane_duplicate_state,
 	.disable_plane		= drm_atomic_helper_disable_plane,
-	.reset			= drm_atomic_helper_plane_reset,
+	.reset			= vs_plane_reset,
 	.update_plane		= drm_atomic_helper_update_plane,
 };
 
-- 
2.52.0