drm: xlnx: zynqmp_dpsub: Add support for live video input

Add partial live video support, with a single video input that bypasses
blending. Skip registration of the DRM device in that case, but register
the DRM bridge instead. The DRM device will be created by the driver for
the display controller in the PL.

Full live video mode with concurrent usage of the video and gfx inputs,
and blending in the DPSUB video pipeline, is currently unsupported.

Signed-off-by: Laurent Pinchart <[e-mail]>

drivers/gpu/drm/xlnx/zynqmp_dp.c

···
 #include <drm/drm_crtc.h>
 #include <drm/drm_device.h>
 #include <drm/drm_edid.h>
+#include <drm/drm_fourcc.h>
 #include <drm/drm_modes.h>
 #include <drm/drm_of.h>
 
···
 }
 
 /* -----------------------------------------------------------------------------
+ * DISP Configuration
+ */
+
+static void zynqmp_dp_disp_enable(struct zynqmp_dp *dp,
+				  struct drm_bridge_state *old_bridge_state)
+{
+	enum zynqmp_dpsub_layer_id layer_id;
+	struct zynqmp_disp_layer *layer;
+	const struct drm_format_info *info;
+
+	if (dp->dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_LIVE_VIDEO))
+		layer_id = ZYNQMP_DPSUB_LAYER_VID;
+	else if (dp->dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_LIVE_GFX))
+		layer_id = ZYNQMP_DPSUB_LAYER_GFX;
+	else
+		return;
+
+	layer = dp->dpsub->layers[layer_id];
+
+	/* TODO: Make the format configurable. */
+	info = drm_format_info(DRM_FORMAT_YUV422);
+	zynqmp_disp_layer_set_format(layer, info);
+	zynqmp_disp_layer_enable(layer, ZYNQMP_DPSUB_LAYER_LIVE);
+
+	if (layer_id == ZYNQMP_DPSUB_LAYER_GFX)
+		zynqmp_disp_blend_set_global_alpha(dp->dpsub->disp, true, 255);
+	else
+		zynqmp_disp_blend_set_global_alpha(dp->dpsub->disp, false, 0);
+
+	zynqmp_disp_enable(dp->dpsub->disp);
+}
+
+static void zynqmp_dp_disp_disable(struct zynqmp_dp *dp,
+				   struct drm_bridge_state *old_bridge_state)
+{
+	struct zynqmp_disp_layer *layer;
+
+	if (dp->dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_LIVE_VIDEO))
+		layer = dp->dpsub->layers[ZYNQMP_DPSUB_LAYER_VID];
+	else if (dp->dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_LIVE_GFX))
+		layer = dp->dpsub->layers[ZYNQMP_DPSUB_LAYER_GFX];
+	else
+		return;
+
+	zynqmp_disp_disable(dp->dpsub->disp);
+	zynqmp_disp_layer_disable(layer);
+}
+
+/* -----------------------------------------------------------------------------
  * DRM Bridge
  */
 
···
 
 	pm_runtime_get_sync(dp->dev);
 
+	zynqmp_dp_disp_enable(dp, old_bridge_state);
+
 	/*
 	 * Retrieve the CRTC mode and adjusted mode. This requires a little
 	 * dance to go from the bridge to the encoder, to the connector and to
···
 			ZYNQMP_DP_TX_PHY_POWER_DOWN_ALL);
 	if (zynqmp_dpsub_audio_enabled(dp->dpsub))
 		zynqmp_dp_write(dp, ZYNQMP_DP_TX_AUDIO_CONTROL, 0);
+
+	zynqmp_dp_disp_disable(dp, old_bridge_state);
+
 	pm_runtime_put_sync(dp->dev);
 }
 

drivers/gpu/drm/xlnx/zynqmp_dpsub.c

···
 #include <linux/slab.h>
 
 #include <drm/drm_atomic_helper.h>
+#include <drm/drm_bridge.h>
 #include <drm/drm_modeset_helper.h>
 #include <drm/drm_module.h>
 
···
 	}
 
 	/* Sanity checks. */
-	if ((dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_LIVE_VIDEO)) ||
-	    (dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_LIVE_GFX)))
-		dev_warn(dpsub->dev, "live video unsupported, ignoring\n");
+	if ((dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_LIVE_VIDEO)) &&
+	    (dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_LIVE_GFX))) {
+		dev_err(dpsub->dev, "only one live video input is supported\n");
+		return -EINVAL;
+	}
 
-	dpsub->dma_enabled = true;
+	if ((dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_LIVE_VIDEO)) ||
+	    (dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_LIVE_GFX))) {
+		if (dpsub->vid_clk_from_ps) {
+			dev_err(dpsub->dev,
+				"live video input requires PL clock\n");
+			return -EINVAL;
+		}
+	} else {
+		dpsub->dma_enabled = true;
+	}
 
 	if (dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_LIVE_AUDIO))
 		dev_warn(dpsub->dev, "live audio unsupported, ignoring\n");
···
 	if (ret)
 		goto err_dp;
 
-	ret = zynqmp_dpsub_drm_init(dpsub);
-	if (ret)
-		goto err_disp;
+	if (dpsub->dma_enabled) {
+		ret = zynqmp_dpsub_drm_init(dpsub);
+		if (ret)
+			goto err_disp;
+	} else {
+		drm_bridge_add(dpsub->bridge);
+	}
 
 	dev_info(&pdev->dev, "ZynqMP DisplayPort Subsystem driver probed");
 
···
 
 	if (dpsub->drm)
 		zynqmp_dpsub_drm_cleanup(dpsub);
+	else
+		drm_bridge_remove(dpsub->bridge);
 
 	zynqmp_disp_remove(dpsub);
 	zynqmp_dp_remove(dpsub);