From: Chun-Kuang Hu <chunkuang.hu@kernel.org>

CMDQ is used to update display register in vblank period, so
it should be execute in next 2 vblank. One vblank interrupt
before send message (occasionally) and one vblank interrupt
after cmdq done. If it fail to execute in next 3 vblank,
tiemout happen.

Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Signed-off-by: jason-jh.lin <redacted>
Reviewed-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
---
 drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
index e23e3224ac67..dad1f85ee315 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c

@@ -54,6 +54,7 @@ struct mtk_drm_crtc {
 #if IS_REACHABLE(CONFIG_MTK_CMDQ)
        struct cmdq_client              cmdq_client;
        u32                             cmdq_event;
+       u32                             cmdq_vblank_cnt;
 #endif

        struct device                   *mmsys_dev;

@@ -227,7 +228,10 @@ struct mtk_ddp_comp *mtk_drm_ddp_comp_for_plane(struct drm_crtc *crtc,
 static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
 {
        struct cmdq_cb_data *data = mssg;
+       struct cmdq_client *cmdq_cl = container_of(cl, struct cmdq_client, client);
+       struct mtk_drm_crtc *mtk_crtc = container_of(cmdq_cl, struct mtk_drm_crtc, cmdq_client);

+       mtk_crtc->cmdq_vblank_cnt = 0;
        cmdq_pkt_destroy(data->pkt);
 }
 #endif

@@ -483,6 +487,15 @@ static void mtk_drm_crtc_update_config(struct mtk_drm_crtc *mtk_crtc,
                                           cmdq_handle->pa_base,
                                           cmdq_handle->cmd_buf_size,
                                           DMA_TO_DEVICE);
+               /*
+                * CMDQ command should execute in next 3 vblank.
+                * One vblank interrupt before send message (occasionally)
+                * and one vblank interrupt after cmdq done,
+                * so it's timeout after 3 vblank interrupt.
+                * If it fail to execute in next 3 vblank, timeout happen.
+                */
+               mtk_crtc->cmdq_vblank_cnt = 3;
+
                mbox_send_message(mtk_crtc->cmdq_client.chan, cmdq_handle);
                mbox_client_txdone(mtk_crtc->cmdq_client.chan, 0);
        }

@@ -499,11 +512,14 @@ static void mtk_crtc_ddp_irq(void *data)

 #if IS_REACHABLE(CONFIG_MTK_CMDQ)
        if (!priv->data->shadow_register && !mtk_crtc->cmdq_client.chan)
+               mtk_crtc_ddp_config(crtc, NULL);
+       else if (mtk_crtc->cmdq_vblank_cnt > 0 && --mtk_crtc->cmdq_vblank_cnt == 0)