drm/mediatek: apply CMDQ control flow

In some Mediatek SoC, there is no "shadow"
registers for performaing an atomic video mode
set or page flip at vblank/vsync.

The CMDQ (Commend Queue) is used to help
update all relevant display controller registers
with critical time limation.
Signed-off-by: YT Shen <yt.shen@mediatek.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Bibby Hsieh <bibby.hsieh@mediatek.com>
Signed-off-by: Yongqiang Niu <yongqiang.niu@mediatek.com>
Signed-off-by: CK Hu <ck.hu@mediatek.com>

drivers/gpu/drm/mediatek/mtk_drm_crtc.c

@@ -5,6 +5,7 @@
 
 #include <linux/clk.h>
 #include <linux/pm_runtime.h>
+#include <linux/soc/mediatek/mtk-cmdq.h>
 
 #include <asm/barrier.h>
 #include <soc/mediatek/smi.h>
@@ -44,6 +45,11 @@ struct mtk_drm_crtc {
 	bool				pending_planes;
 	bool				pending_async_planes;
 
+#if IS_REACHABLE(CONFIG_MTK_CMDQ)
+	struct cmdq_client		*cmdq_client;
+	u32				cmdq_event;
+#endif
+
 	void __iomem			*config_regs;
 	struct mtk_disp_mutex		*mutex;
 	unsigned int			ddp_comp_nr;
@@ -234,6 +240,13 @@ struct mtk_ddp_comp *mtk_drm_ddp_comp_for_plane(struct drm_crtc *crtc,
 	return NULL;
 }
 
+#if IS_REACHABLE(CONFIG_MTK_CMDQ)
+static void ddp_cmdq_cb(struct cmdq_cb_data data)
+{
+	cmdq_pkt_destroy(data.data);
+}
+#endif
+
 static int mtk_crtc_ddp_hw_init(struct mtk_drm_crtc *mtk_crtc)
 {
 	struct drm_crtc *crtc = &mtk_crtc->base;
@@ -367,7 +380,8 @@ static void mtk_crtc_ddp_hw_fini(struct mtk_drm_crtc *mtk_crtc)
 	}
 }
 
-static void mtk_crtc_ddp_config(struct drm_crtc *crtc)
+static void mtk_crtc_ddp_config(struct drm_crtc *crtc,
+				struct cmdq_pkt *cmdq_handle)
 {
 	struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
 	struct mtk_crtc_state *state = to_mtk_crtc_state(mtk_crtc->base.state);
@@ -383,7 +397,8 @@ static void mtk_crtc_ddp_config(struct drm_crtc *crtc)
 	if (state->pending_config) {
 		mtk_ddp_comp_config(comp, state->pending_width,
 				    state->pending_height,
-				    state->pending_vrefresh, 0, NULL);
+				    state->pending_vrefresh, 0,
+				    cmdq_handle);
 
 		state->pending_config = false;
 	}
@@ -403,7 +418,8 @@ static void mtk_crtc_ddp_config(struct drm_crtc *crtc)
 
 			if (comp)
 				mtk_ddp_comp_layer_config(comp, local_layer,
-							  plane_state, NULL);
+							  plane_state,
+							  cmdq_handle);
 			plane_state->pending.config = false;
 		}
 		mtk_crtc->pending_planes = false;
@@ -424,7 +440,8 @@ static void mtk_crtc_ddp_config(struct drm_crtc *crtc)
 
 			if (comp)
 				mtk_ddp_comp_layer_config(comp, local_layer,
-							  plane_state, NULL);
+							  plane_state,
+							  cmdq_handle);
 			plane_state->pending.async_config = false;
 		}
 		mtk_crtc->pending_async_planes = false;
@@ -433,6 +450,9 @@ static void mtk_crtc_ddp_config(struct drm_crtc *crtc)
 
 static void mtk_drm_crtc_hw_config(struct mtk_drm_crtc *mtk_crtc)
 {
+#if IS_REACHABLE(CONFIG_MTK_CMDQ)
+	struct cmdq_pkt *cmdq_handle;
+#endif
 	struct drm_crtc *crtc = &mtk_crtc->base;
 	struct mtk_drm_private *priv = crtc->dev->dev_private;
 	unsigned int pending_planes = 0, pending_async_planes = 0;
@@ -461,9 +481,18 @@ static void mtk_drm_crtc_hw_config(struct mtk_drm_crtc *mtk_crtc)
 
 	if (priv->data->shadow_register) {
 		mtk_disp_mutex_acquire(mtk_crtc->mutex);
-		mtk_crtc_ddp_config(crtc);
+		mtk_crtc_ddp_config(crtc, NULL);
 		mtk_disp_mutex_release(mtk_crtc->mutex);
 	}
+#if IS_REACHABLE(CONFIG_MTK_CMDQ)
+	if (mtk_crtc->cmdq_client) {
+		cmdq_handle = cmdq_pkt_create(mtk_crtc->cmdq_client, PAGE_SIZE);
+		cmdq_pkt_clear_event(cmdq_handle, mtk_crtc->cmdq_event);
+		cmdq_pkt_wfe(cmdq_handle, mtk_crtc->cmdq_event);
+		mtk_crtc_ddp_config(crtc, cmdq_handle);
+		cmdq_pkt_flush_async(cmdq_handle, ddp_cmdq_cb, cmdq_handle);
+	}
+#endif
 	mutex_unlock(&mtk_crtc->hw_lock);
 }
 
@@ -629,8 +658,12 @@ void mtk_crtc_ddp_irq(struct drm_crtc *crtc, struct mtk_ddp_comp *comp)
 	struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
 	struct mtk_drm_private *priv = crtc->dev->dev_private;
 
+#if IS_REACHABLE(CONFIG_MTK_CMDQ)
+	if (!priv->data->shadow_register && !mtk_crtc->cmdq_client)
+#else
 	if (!priv->data->shadow_register)
-		mtk_crtc_ddp_config(crtc);
+#endif
+		mtk_crtc_ddp_config(crtc, NULL);
 
 	mtk_drm_finish_page_flip(mtk_crtc);
 }
@@ -772,5 +805,21 @@ int mtk_drm_crtc_create(struct drm_device *drm_dev,
 	priv->num_pipes++;
 	mutex_init(&mtk_crtc->hw_lock);
 
+#if IS_REACHABLE(CONFIG_MTK_CMDQ)
+	mtk_crtc->cmdq_client =
+			cmdq_mbox_create(dev, drm_crtc_index(&mtk_crtc->base),
+					 2000);
+	if (IS_ERR(mtk_crtc->cmdq_client)) {
+		dev_dbg(dev, "mtk_crtc %d failed to create mailbox client, writing register by CPU now\n",
+			drm_crtc_index(&mtk_crtc->base));
+		mtk_crtc->cmdq_client = NULL;
+	}
+	ret = of_property_read_u32_index(dev->of_node, "mediatek,gce-events",
+					 drm_crtc_index(&mtk_crtc->base),
+					 &mtk_crtc->cmdq_event);
+	if (ret)
+		dev_dbg(dev, "mtk_crtc %d failed to get mediatek,gce-events property\n",
+			drm_crtc_index(&mtk_crtc->base));
+#endif
 	return 0;
 }