[PATCH 5.15 146/230] drm/mediatek: Detect CMDQ execution timeout

Greg Kroah-Hartman
2022-07-11T09:54:55Z

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

[ Upstream commit eaf80126aba6fd1754837eec91e4c8bbd58ae52e ]

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 <jason-jh.lin@mediatek.com>
Signed-off-by: Sasha Levin <sashal@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)
+ 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);
}

--
2.35.1