[PATCH v2] drm/mediatek: add dma buffer control for drm plane disable

[Yongqiang Niu]

dma buffer release before overlay disable, that will cause
m4u translation fault warning.

add dma buffer control flow in mediatek driver:
get dma buffer when drm plane disable
put dma buffer when overlay really disable

Signed-off-by: Yongqiang Niu <yongqiang.niu@xxxxxxxxxxxx>
---
 drivers/gpu/drm/mediatek/mtk_drm_crtc.c  | 19 +++++++++++++++++--
 drivers/gpu/drm/mediatek/mtk_drm_plane.c | 12 ++++++++++++
 drivers/gpu/drm/mediatek/mtk_drm_plane.h |  1 +
 3 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
index 5071f1263216..ff7924d8a167 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/clk.h>
+#include <linux/dma-buf.h>
 #include <linux/dma-mapping.h>
 #include <linux/mailbox_controller.h>
 #include <linux/pm_runtime.h>
@@ -282,6 +283,14 @@ struct mtk_ddp_comp *mtk_drm_ddp_comp_for_plane(struct drm_crtc *crtc,
 	return NULL;
 }
 
+static void mtk_drm_dma_buf_put(struct mtk_plane_state *plane_state)
+{
+	if (plane_state && plane_state->pending.dma_buf) {
+		dma_buf_put(plane_state->pending.dma_buf);
+		plane_state->pending.dma_buf = NULL;
+	}
+}
+
 #if IS_REACHABLE(CONFIG_MTK_CMDQ)
 static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
 {
@@ -306,6 +315,7 @@ static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
 			plane_state = to_mtk_plane_state(plane->state);
 
 			plane_state->pending.config = false;
+			mtk_drm_dma_buf_put(plane_state);
 		}
 		mtk_crtc->pending_planes = false;
 	}
@@ -318,6 +328,7 @@ static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
 			plane_state = to_mtk_plane_state(plane->state);
 
 			plane_state->pending.async_config = false;
+			mtk_drm_dma_buf_put(plane_state);
 		}
 		mtk_crtc->pending_async_planes = false;
 	}
@@ -498,8 +509,10 @@ static void mtk_crtc_ddp_config(struct drm_crtc *crtc,
 				mtk_ddp_comp_layer_config(comp, local_layer,
 							  plane_state,
 							  cmdq_handle);
-			if (!cmdq_handle)
+			if (!cmdq_handle) {
 				plane_state->pending.config = false;
+				mtk_drm_dma_buf_put(plane_state);
+			}
 		}
 
 		if (!cmdq_handle)
@@ -523,8 +536,10 @@ static void mtk_crtc_ddp_config(struct drm_crtc *crtc,
 				mtk_ddp_comp_layer_config(comp, local_layer,
 							  plane_state,
 							  cmdq_handle);
-			if (!cmdq_handle)
+			if (!cmdq_handle) {
 				plane_state->pending.async_config = false;
+				mtk_drm_dma_buf_put(plane_state);
+			}
 		}
 
 		if (!cmdq_handle)
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_plane.c b/drivers/gpu/drm/mediatek/mtk_drm_plane.c
index d54fbf34b000..16495a057c42 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_plane.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_plane.c
@@ -12,6 +12,7 @@
 #include <drm/drm_framebuffer.h>
 #include <drm/drm_gem_atomic_helper.h>
 #include <linux/align.h>
+#include <linux/dma-buf.h>
 
 #include "mtk_drm_crtc.h"
 #include "mtk_drm_ddp_comp.h"
@@ -280,6 +281,17 @@ static void mtk_plane_atomic_disable(struct drm_plane *plane,
 	struct drm_plane_state *new_state = drm_atomic_get_new_plane_state(state,
 									   plane);
 	struct mtk_plane_state *mtk_plane_state = to_mtk_plane_state(new_state);
+	struct drm_plane_state *old_state = drm_atomic_get_old_plane_state(state,
+									   plane);
+
+	if (old_state && old_state->fb) {
+		struct drm_gem_object *gem = old_state->fb->obj[0];
+
+		if (gem && gem->dma_buf) {
+			get_dma_buf(gem->dma_buf);
+			mtk_plane_state->pending.dma_buf = gem->dma_buf;
+		}
+	}
 	mtk_plane_state->pending.enable = false;
 	wmb(); /* Make sure the above parameter is set before update */
 	mtk_plane_state->pending.dirty = true;
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_plane.h b/drivers/gpu/drm/mediatek/mtk_drm_plane.h
index 8f39011cdbfc..b724e56b7283 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_plane.h
+++ b/drivers/gpu/drm/mediatek/mtk_drm_plane.h
@@ -33,6 +33,7 @@ struct mtk_plane_pending_state {
 	bool				async_dirty;
 	bool				async_config;
 	enum drm_color_encoding		color_encoding;
+	struct dma_buf			*dma_buf;
 };
 
 struct mtk_plane_state {
-- 
2.25.1