drm/mediatek: Add vblank register/unregister callback functions

We encountered a kernel panic issue that callback data will be NULL when
it's using in ovl irq handler. There is a timing issue between
mtk_disp_ovl_irq_handler() and mtk_ovl_disable_vblank().

To resolve this issue, we use the flow to register/unregister vblank cb:
- Register callback function and callback data when crtc creates.
- Unregister callback function and callback data when crtc destroies.

With this solution, we can assure callback data will not be NULL when
vblank is disable.

Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20220321072320.15019-1-rex-bc.chen@mediatek.com/
Fixes: 9b0704988b15 ("drm/mediatek: Register vblank callback function")
Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
Reviewed-by: jason-jh.lin <jason-jh.lin@mediatek.com>
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

1 files changed, 13 insertions, 1 deletions

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
index a6adc4ea48e1..42cc7052b050 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
@@ -152,6 +152,7 @@ static void mtk_drm_cmdq_pkt_destroy(struct cmdq_pkt *pkt)
 static void mtk_drm_crtc_destroy(struct drm_crtc *crtc)
 {
 	struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
+	int i;
 
 	mtk_mutex_put(mtk_crtc->mutex);
 #if IS_REACHABLE(CONFIG_MTK_CMDQ)
@@ -162,6 +163,14 @@ static void mtk_drm_crtc_destroy(struct drm_crtc *crtc)
 		mtk_crtc->cmdq_client.chan = NULL;
 	}
 #endif
+
+	for (i = 0; i < mtk_crtc->ddp_comp_nr; i++) {
+		struct mtk_ddp_comp *comp;
+
+		comp = mtk_crtc->ddp_comp[i];
+		mtk_ddp_comp_unregister_vblank_cb(comp);
+	}
+
 	drm_crtc_cleanup(crtc);
 }
 
@@ -618,7 +627,7 @@ static int mtk_drm_crtc_enable_vblank(struct drm_crtc *crtc)
 	struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
 	struct mtk_ddp_comp *comp = mtk_crtc->ddp_comp[0];
 
-	mtk_ddp_comp_enable_vblank(comp, mtk_crtc_ddp_irq, &mtk_crtc->base);
+	mtk_ddp_comp_enable_vblank(comp);
 
 	return 0;
 }
@@ -927,6 +936,9 @@ int mtk_drm_crtc_create(struct drm_device *drm_dev,
 			if (comp->funcs->ctm_set)
 				has_ctm = true;
 		}
+
+		mtk_ddp_comp_register_vblank_cb(comp, mtk_crtc_ddp_irq,
+						&mtk_crtc->base);
 	}
 
 	for (i = 0; i < mtk_crtc->ddp_comp_nr; i++)