[PATCH drm-misc-next v4 2/4] drm: verisilicon: subclass drm_plane_state

Icenowy Zheng
2026-03-31T06:01:51Z

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