[PATCH v2 3/4] drm/mediatek: Detect CMDQ execution timeout

[Chun-Kuang Hu]

CMDQ is used to update display register in vblank period, so
it should be execute in next vblank. If it fail to execute
in next 2 vblank, tiemout happen.

Signed-off-by: Chun-Kuang Hu <chunkuang...@kernel.org>
---
 drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c 
b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
index da92a3fedd0a..ad4c1a3a9294 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
@@ -55,6 +55,7 @@ struct mtk_drm_crtc {
        struct mbox_client              cmdq_cl;
        struct mbox_chan                *cmdq_chan;
        u32                             cmdq_event;
+       u32                             cmdq_vblank_cnt;
 #endif
 
        struct device                   *mmsys_dev;
@@ -269,6 +270,7 @@ static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
        struct mtk_drm_crtc *mtk_crtc = container_of(cl, struct mtk_drm_crtc, 
cmdq_cl);
        struct cmdq_cb_data *data = mssg;
 
+       mtk_crtc->cmdq_vblank_cnt = 0;
        mtk_drm_cmdq_pkt_destroy(mtk_crtc->cmdq_chan, data->pkt);
 }
 #endif
@@ -524,6 +526,11 @@ 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 vblank,
+                * If it fail to execute in next 2 vblank, timeout happen.
+                */
+               mtk_crtc->cmdq_vblank_cnt = 2;
                mbox_send_message(mtk_crtc->cmdq_chan, cmdq_handle);
                mbox_client_txdone(mtk_crtc->cmdq_chan, 0);
        }
@@ -540,11 +547,14 @@ static void mtk_crtc_ddp_irq(void *data)
 
 #if IS_REACHABLE(CONFIG_MTK_CMDQ)
        if (!priv->data->shadow_register && !mtk_crtc->cmdq_chan)
+               mtk_crtc_ddp_config(crtc, NULL);
+       else if (mtk_crtc->cmdq_vblank_cnt > 0 && --mtk_crtc->cmdq_vblank_cnt 
== 0)
+               DRM_ERROR("mtk_crtc %d CMDQ execute command timeout!\n",
+                         drm_crtc_index(&mtk_crtc->base));
 #else
        if (!priv->data->shadow_register)
-#endif
                mtk_crtc_ddp_config(crtc, NULL);
-
+#endif
        mtk_drm_finish_page_flip(mtk_crtc);
 }
 
-- 
2.25.1