Re: [PATCH v8 3/3] drm/mediatek: Implement OF graphs support for display paths

["CK Hu (胡俊光)" <ck.hu@mediatek.com>]

Hi, Angelo:

On Tue, 2024-06-18 at 12:17 +0200, AngeloGioacchino Del Regno wrote:
> It is impossible to add each and every possible DDP path combination
> for each and every possible combination of SoC and board: right now,
> this driver hardcodes configuration for 10 SoCs and this is going to
> grow larger and larger, and with new hacks like the introduction of
> mtk_drm_route which is anyway not enough for all final routes as the
> DSI cannot be connected to MERGE if it's not a dual-DSI, or enabling
> DSC preventively doesn't work if the display doesn't support it, or
> others.
> 
> Since practically all display IPs in MediaTek SoCs support being
> interconnected with different instances of other, or the same, IPs
> or with different IPs and in different combinations, the final DDP
> pipeline is effectively a board specific configuration.
> 
> Implement OF graphs support to the mediatek-drm drivers, allowing to
> stop hardcoding the paths, and preventing this driver to get a huge
> amount of arrays for each board and SoC combination, also paving the
> way to share the same mtk_mmsys_driver_data between multiple SoCs,
> making it more straightforward to add support for new chips.
> 
> Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
> Tested-by: Alexandre Mergnat <amergnat@baylibre.com>
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ---

[snip]

> +static int mtk_drm_of_ddp_path_build_one(struct device *dev, enum mtk_crtc_path cpath,
> +					 const unsigned int **out_path,
> +					 unsigned int *out_path_len)
> +{
> +	struct device_node *next, *prev, *vdo = dev->parent->of_node;
> +	unsigned int temp_path[DDP_COMPONENT_DRM_ID_MAX] = { 0 };
> +	unsigned int *final_ddp_path;
> +	unsigned short int idx = 0;
> +	bool ovl_adaptor_comp_added = false;
> +	int ret;
> +
> +	/* Get the first entry for the temp_path array */
> +	ret = mtk_drm_of_get_ddp_ep_cid(vdo, 0, cpath, &next, &temp_path[idx]);
> +	if (ret) {
> +		if (next && temp_path[idx] == DDP_COMPONENT_DRM_OVL_ADAPTOR) {
> +			dev_err(dev, "Adding OVL Adaptor for %pOF\n", next);

This looks not an error.

> +			ovl_adaptor_comp_added = true;
> +		} else {
> +			if (next)
> +				dev_err(dev, "Invalid component %pOF\n", next);
> +			else
> +				dev_err(dev, "Cannot find first endpoint for path %d\n", cpath);
> +
> +			return ret;
> +		}
> +	}
> +	idx++;
> +
> +	/*
> +	 * Walk through port outputs until we reach the last valid mediatek-drm component.
> +	 * To be valid, this must end with an "invalid" component that is a display node.
> +	 */
> +	do {
> +		prev = next;
> +		ret = mtk_drm_of_get_ddp_ep_cid(next, 1, cpath, &next, &temp_path[idx]);
> +		of_node_put(prev);
> +		if (ret) {
> +			of_node_put(next);
> +			break;
> +		}
> +
> +		/*
> +		 * If this is an OVL adaptor exclusive component and one of those
> +		 * was already added, don't add another instance of the generic
> +		 * DDP_COMPONENT_OVL_ADAPTOR, as this is used only to decide whether
> +		 * to probe that component master driver of which only one instance
> +		 * is needed and possible.
> +		 */
> +		if (temp_path[idx] == DDP_COMPONENT_DRM_OVL_ADAPTOR) {
> +			if (!ovl_adaptor_comp_added)
> +				ovl_adaptor_comp_added = true;
> +			else
> +				idx--;
> +		}
> +	} while (++idx < DDP_COMPONENT_DRM_ID_MAX);
> +
> +	/*
> +	 * The device component might not be enabled: in that case, don't
> +	 * check the last entry and just report that the device is missing.
> +	 */
> +	if (ret == -ENODEV)
> +		return ret;
> +
> +	/* If the last entry is not a final display output, the configuration is wrong */
> +	switch (temp_path[idx - 1]) {
> +	case DDP_COMPONENT_DP_INTF0:
> +	case DDP_COMPONENT_DP_INTF1:
> +	case DDP_COMPONENT_DPI0:
> +	case DDP_COMPONENT_DPI1:
> +	case DDP_COMPONENT_DSI0:
> +	case DDP_COMPONENT_DSI1:
> +	case DDP_COMPONENT_DSI2:
> +	case DDP_COMPONENT_DSI3:
> +		break;
> +	default:
> +		dev_err(dev, "Invalid display hw pipeline. Last component: %d (ret=%d)\n",
> +			temp_path[idx - 1], ret);
> +		return -EINVAL;
> +	}
> +
> +	final_ddp_path = devm_kmemdup(dev, temp_path, idx * sizeof(temp_path[0]), GFP_KERNEL);
> +	if (!final_ddp_path)
> +		return -ENOMEM;
> +
> +	dev_dbg(dev, "Display HW Pipeline built with %d components.\n", idx);
> +
> +	/* Pipeline built! */
> +	*out_path = final_ddp_path;
> +	*out_path_len = idx;
> +
> +	return 0;
> +}
> +
> +static int mtk_drm_of_ddp_path_build(struct device *dev, struct device_node *node,
> +				     struct mtk_mmsys_driver_data *data)
> +{
> +	struct device_node *ep_node;
> +	struct of_endpoint of_ep;
> +	bool output_present[MAX_CRTC] = { false };
> +	int ret;
> +
> +	for_each_endpoint_of_node(node, ep_node) {
> +		ret = of_graph_parse_endpoint(ep_node, &of_ep);
> +		if (ret) {
> +			dev_err_probe(dev, ret, "Cannot parse endpoint\n");
> +			break;
> +		}
> +
> +		if (of_ep.id >= MAX_CRTC) {
> +			ret = dev_err_probe(dev, -EINVAL,
> +					    "Invalid endpoint%u number\n", of_ep.port);
> +			break;
> +		}
> +
> +		output_present[of_ep.id] = true;
> +	}
> +
> +	if (ret) {
> +		of_node_put(ep_node);
> +		return ret;
> +	}
> +
> +	if (output_present[CRTC_MAIN]) {
> +		ret = mtk_drm_of_ddp_path_build_one(dev, CRTC_MAIN,
> +						    &data->main_path, &data->main_len);
> +		if (ret && ret != -ENODEV)
> +			return ret;
> +	}
> +
> +	if (output_present[CRTC_EXT]) {
> +		ret = mtk_drm_of_ddp_path_build_one(dev, CRTC_EXT,
> +						    &data->ext_path, &data->ext_len);
> +		if (ret && ret != -ENODEV)
> +			return ret;
> +	}
> +
> +	if (output_present[CRTC_THIRD]) {
> +		ret = mtk_drm_of_ddp_path_build_one(dev, CRTC_THIRD,
> +						    &data->third_path, &data->third_len);
> +		if (ret && ret != -ENODEV)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
>  static int mtk_drm_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
>  	struct device_node *phandle = dev->parent->of_node;
>  	const struct of_device_id *of_id;
>  	struct mtk_drm_private *private;
> +	struct mtk_mmsys_driver_data *mtk_drm_data;
>  	struct device_node *node;
>  	struct component_match *match = NULL;
>  	struct platform_device *ovl_adaptor;
> @@ -824,7 +1048,31 @@ static int mtk_drm_probe(struct platform_device *pdev)
>  	if (!of_id)
>  		return -ENODEV;
>  
> -	private->data = of_id->data;
> +	mtk_drm_data = (struct mtk_mmsys_driver_data *)of_id->data;
> +	if (!mtk_drm_data)
> +		return -EINVAL;
> +
> +	private->data = kmemdup(mtk_drm_data, sizeof(*mtk_drm_data), GFP_KERNEL);

This is redundant. You would assign private->data below.

> +	if (!private->data)
> +		return -ENOMEM;
> +
> +	/* Try to build the display pipeline from devicetree graphs */
> +	if (of_graph_is_present(phandle)) {
> +		dev_dbg(dev, "Building display pipeline for MMSYS %u\n",
> +			mtk_drm_data->mmsys_id);
> +		private->data = devm_kmemdup(dev, mtk_drm_data,
> +					     sizeof(*mtk_drm_data), GFP_KERNEL);
> +		if (!private->data)
> +			return -ENOMEM;
> +
> +		ret = mtk_drm_of_ddp_path_build(dev, phandle, private->data);
> +		if (ret)
> +			return ret;
> +	} else {
> +		/* No devicetree graphs support: go with hardcoded paths if present */
> +		dev_dbg(dev, "Using hardcoded paths for MMSYS %u\n", mtk_drm_data->mmsys_id);
> +		private->data = mtk_drm_data;
> +	};
>  
>  	private->all_drm_private = devm_kmalloc_array(dev, private->data->mmsys_dev_num,
>  						      sizeof(*private->all_drm_private),
> @@ -846,12 +1094,11 @@ static int mtk_drm_probe(struct platform_device *pdev)
>  
>  	/* Iterate over sibling DISP function blocks */
>  	for_each_child_of_node(phandle->parent, node) {
> -		const struct of_device_id *of_id;
>  		enum mtk_ddp_comp_type comp_type;
>  		int comp_id;
>  
> -		of_id = of_match_node(mtk_ddp_comp_dt_ids, node);
> -		if (!of_id)
> +		ret = mtk_drm_of_get_ddp_comp_type(node, &comp_type);
> +		if (ret)
>  			continue;
>  
>  		if (!of_device_is_available(node)) {
> @@ -860,8 +1107,6 @@ static int mtk_drm_probe(struct platform_device *pdev)
>  			continue;
>  		}
>  
> -		comp_type = (enum mtk_ddp_comp_type)(uintptr_t)of_id->data;
> -
>  		if (comp_type == MTK_DISP_MUTEX) {
>  			int id;
>  
> @@ -890,22 +1135,24 @@ static int mtk_drm_probe(struct platform_device *pdev)
>  		 * blocks have separate component platform drivers and initialize their own
>  		 * DDP component structure. The others are initialized here.
>  		 */
> -		if (comp_type == MTK_DISP_AAL ||
> -		    comp_type == MTK_DISP_CCORR ||
> -		    comp_type == MTK_DISP_COLOR ||
> -		    comp_type == MTK_DISP_GAMMA ||
> -		    comp_type == MTK_DISP_MERGE ||
> -		    comp_type == MTK_DISP_OVL ||
> -		    comp_type == MTK_DISP_OVL_2L ||
> -		    comp_type == MTK_DISP_OVL_ADAPTOR ||
> -		    comp_type == MTK_DISP_RDMA ||
> -		    comp_type == MTK_DP_INTF ||
> -		    comp_type == MTK_DPI ||
> -		    comp_type == MTK_DSI) {
> -			dev_info(dev, "Adding component match for %pOF\n",
> -				 node);
> -			drm_of_component_match_add(dev, &match, component_compare_of,
> -						   node);
> +		switch (comp_type) {
> +		default:
> +			break;
> +		case MTK_DISP_AAL:
> +		case MTK_DISP_CCORR:
> +		case MTK_DISP_COLOR:
> +		case MTK_DISP_GAMMA:
> +		case MTK_DISP_MERGE:
> +		case MTK_DISP_OVL:
> +		case MTK_DISP_OVL_2L:
> +		case MTK_DISP_OVL_ADAPTOR:
> +		case MTK_DISP_RDMA:
> +		case MTK_DP_INTF:
> +		case MTK_DPI:
> +		case MTK_DSI:
> +			dev_info(dev, "Adding component match for %pOF\n", node);
> +			drm_of_component_match_add(dev, &match, component_compare_of, node);
> +			break;

This modification seems not related to OF graphs support. If you need this, separate this to another patch.

>  		}
>  
>  		ret = mtk_ddp_comp_init(node, &private->ddp_comp[comp_id], comp_id);
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.h b/drivers/gpu/drm/mediatek/mtk_drm_drv.h
> index 78d698ede1bf..7e54d86e25a3 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.h
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.h
> @@ -59,7 +59,7 @@ struct mtk_drm_private {
>  	struct device *mmsys_dev;
>  	struct device_node *comp_node[DDP_COMPONENT_DRM_ID_MAX];
>  	struct mtk_ddp_comp ddp_comp[DDP_COMPONENT_DRM_ID_MAX];
> -	const struct mtk_mmsys_driver_data *data;
> +	struct mtk_mmsys_driver_data *data;
>  	struct drm_atomic_state *suspend_state;
>  	unsigned int mbox_index;
>  	struct mtk_drm_private **all_drm_private;
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index c255559cc56e..880ea37937da 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -904,9 +904,17 @@ static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
>  	dsi->lanes = device->lanes;
>  	dsi->format = device->format;
>  	dsi->mode_flags = device->mode_flags;
> -	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
> -	if (IS_ERR(dsi->next_bridge))
> -		return PTR_ERR(dsi->next_bridge);
> +	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
> +	if (IS_ERR(dsi->next_bridge)) {
> +		ret = PTR_ERR(dsi->next_bridge);
> +		if (ret == -EPROBE_DEFER)
> +			return ret;
> +
> +		/* Old devicetree has only one endpoint */
> +		dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
> +		if (IS_ERR(dsi->next_bridge))
> +			return PTR_ERR(dsi->next_bridge);
> +	}
>  
>  	drm_bridge_add(&dsi->bridge);
>