drm: xlnx: zynqmp_dpsub: Support operation without DMA engine

To prepare for usage of the DPSUB as a DisplayPort bridge without
creating a DRM device, make initialization and usage of the DMA engine
optional. The flag that controls this feature is currently hardcoded to
operating with the DMA engine, this will be made dynamic based on the
device tree configuration in a subsequent change.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

drivers/gpu/drm/xlnx/zynqmp_disp.c

@@ -926,8 +926,10 @@ void zynqmp_disp_layer_disable(struct zynqmp_disp_layer *layer)
 {
 	unsigned int i;
 
-	for (i = 0; i < layer->drm_fmt->num_planes; i++)
+	if (layer->disp->dpsub->dma_enabled) {
-		dmaengine_terminate_sync(layer->dmas[i].chan);
+		for (i = 0; i < layer->drm_fmt->num_planes; i++)
+			dmaengine_terminate_sync(layer->dmas[i].chan);
+	}
 
 	zynqmp_disp_avbuf_disable_video(layer->disp, layer);
 	zynqmp_disp_blend_layer_disable(layer->disp, layer);
@@ -950,6 +952,9 @@ void zynqmp_disp_layer_set_format(struct zynqmp_disp_layer *layer,
 
 	zynqmp_disp_avbuf_set_format(layer->disp, layer, layer->disp_fmt);
 
+	if (!layer->disp->dpsub->dma_enabled)
+		return;
+
 	/*
 	 * Set pconfig for each DMA channel to indicate they're part of a
 	 * video group.
@@ -985,6 +990,9 @@ int zynqmp_disp_layer_update(struct zynqmp_disp_layer *layer,
 	const struct drm_format_info *info = layer->drm_fmt;
 	unsigned int i;
 
+	if (!layer->disp->dpsub->dma_enabled)
+		return 0;
+
 	for (i = 0; i < info->num_planes; i++) {
 		unsigned int width = state->crtc_w / (i ? info->hsub : 1);
 		unsigned int height = state->crtc_h / (i ? info->vsub : 1);
@@ -1032,7 +1040,7 @@ static void zynqmp_disp_layer_release_dma(struct zynqmp_disp *disp,
 {
 	unsigned int i;
 
-	if (!layer->info)
+	if (!layer->info || !disp->dpsub->dma_enabled)
 		return;
 
 	for (i = 0; i < layer->info->num_channels; i++) {
@@ -1075,6 +1083,9 @@ static int zynqmp_disp_layer_request_dma(struct zynqmp_disp *disp,
 	unsigned int i;
 	int ret;
 
+	if (!disp->dpsub->dma_enabled)
+		return 0;
+
 	for (i = 0; i < layer->info->num_channels; i++) {
 		struct zynqmp_disp_layer_dma *dma = &layer->dmas[i];
 		char dma_channel_name[16];
@@ -1217,7 +1228,6 @@ int zynqmp_disp_probe(struct zynqmp_dpsub *dpsub)
 {
 	struct platform_device *pdev = to_platform_device(dpsub->dev);
 	struct zynqmp_disp *disp;
-	struct zynqmp_disp_layer *layer;
 	struct resource *res;
 	int ret;
 
@@ -1253,8 +1263,12 @@ int zynqmp_disp_probe(struct zynqmp_dpsub *dpsub)
 	if (ret)
 		goto error;
 
-	layer = &disp->layers[ZYNQMP_DPSUB_LAYER_VID];
+	if (disp->dpsub->dma_enabled) {
-	dpsub->dma_align = 1 << layer->dmas[0].chan->device->copy_align;
+		struct zynqmp_disp_layer *layer;
+
+		layer = &disp->layers[ZYNQMP_DPSUB_LAYER_VID];
+		dpsub->dma_align = 1 << layer->dmas[0].chan->device->copy_align;
+	}
 
 	dpsub->disp = disp;
 

drivers/gpu/drm/xlnx/zynqmp_dpsub.c

@@ -158,6 +158,7 @@ static int zynqmp_dpsub_parse_dt(struct zynqmp_dpsub *dpsub)
 	if (!np) {
 		dev_warn(dpsub->dev, "missing ports, update DT bindings\n");
 		dpsub->connected_ports = BIT(ZYNQMP_DPSUB_PORT_OUT_DP);
+		dpsub->dma_enabled = true;
 		return 0;
 	}
 
@@ -177,6 +178,8 @@ static int zynqmp_dpsub_parse_dt(struct zynqmp_dpsub *dpsub)
 	    (dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_LIVE_GFX)))
 		dev_warn(dpsub->dev, "live video unsupported, ignoring\n");
 
+	dpsub->dma_enabled = true;
+
 	if (dpsub->connected_ports & BIT(ZYNQMP_DPSUB_PORT_LIVE_AUDIO))
 		dev_warn(dpsub->dev, "live audio unsupported, ignoring\n");
 

drivers/gpu/drm/xlnx/zynqmp_dpsub.h

@@ -48,6 +48,8 @@ enum zynqmp_dpsub_format {
  * @aud_clk: Audio clock
  * @aud_clk_from_ps: True of the audio clock comes from PS, false from PL
  * @connected_ports: Bitmask of connected ports in the device tree
+ * @dma_enabled: True if the DMA interface is enabled, false if the DPSUB is
+ *	driven by the live input
  * @drm: The DRM/KMS device data
  * @bridge: The DP encoder bridge
  * @disp: The display controller
@@ -64,6 +66,7 @@ struct zynqmp_dpsub {
 	bool aud_clk_from_ps;
 
 	unsigned int connected_ports;
+	bool dma_enabled;
 
 	struct zynqmp_dpsub_drm *drm;
 	struct drm_bridge *bridge;