Re: [PATCH v16 08/14] remoteproc: mediatek: Probe SCP cluster on multi-core SCP

[Mathieu Poirier <mathieu.poirier@linaro.org>]

Hi Tinghan,

On Fri, Jul 28, 2023 at 10:39:53AM +0800, Tinghan Shen wrote:
> The difference of single-core SCP and multi-core SCP device tree is
> the presence of child device nodes described SCP cores. The SCP
> driver populates the platform device and checks the child nodes
> to identify whether it's a single-core SCP or a multi-core SCP.
> 
> Add the remoteproc instances of multi-core SCP to the SCP cluster list.
> When the SCP driver is removed, it cleanup resources by walking
> through the cluster list.
> 
> Signed-off-by: Tinghan Shen <tinghan.shen@mediatek.com>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ---
>  drivers/remoteproc/mtk_scp.c | 118 +++++++++++++++++++++++++++++++++--
>  1 file changed, 113 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c
> index d67dcabdab9e..d9242c3eb0d7 100644
> --- a/drivers/remoteproc/mtk_scp.c
> +++ b/drivers/remoteproc/mtk_scp.c
> @@ -855,7 +855,8 @@ static void scp_remove_rpmsg_subdev(struct mtk_scp *scp)
>  }
>  
>  static struct mtk_scp *scp_rproc_init(struct platform_device *pdev,
> -				      struct mtk_scp_of_cluster *scp_cluster)
> +				      struct mtk_scp_of_cluster *scp_cluster,
> +				      const struct mtk_scp_of_data *of_data)
>  {
>  	struct device *dev = &pdev->dev;
>  	struct device_node *np = dev->of_node;
> @@ -878,7 +879,7 @@ static struct mtk_scp *scp_rproc_init(struct platform_device *pdev,
>  	scp = rproc->priv;
>  	scp->rproc = rproc;
>  	scp->dev = dev;
> -	scp->data = of_device_get_match_data(dev);
> +	scp->data = of_data;
>  	scp->cluster = scp_cluster;
>  	platform_set_drvdata(pdev, scp);
>  
> @@ -951,15 +952,15 @@ static void scp_free(struct mtk_scp *scp)
>  	mutex_destroy(&scp->send_lock);
>  }
>  
> -static int scp_cluster_init(struct platform_device *pdev,
> -			    struct mtk_scp_of_cluster *scp_cluster)
> +static int scp_add_single_core(struct platform_device *pdev,
> +			       struct mtk_scp_of_cluster *scp_cluster)
>  {
>  	struct device *dev = &pdev->dev;
>  	struct list_head *scp_list = &scp_cluster->mtk_scp_list;
>  	struct mtk_scp *scp;
>  	int ret;
>  
> -	scp = scp_rproc_init(pdev, scp_cluster);
> +	scp = scp_rproc_init(pdev, scp_cluster, of_device_get_match_data(dev));
>  	if (IS_ERR(scp))
>  		return PTR_ERR(scp);
>  
> @@ -975,6 +976,102 @@ static int scp_cluster_init(struct platform_device *pdev,
>  	return 0;
>  }
>  
> +static int scp_add_multi_core(struct platform_device *pdev,
> +			      struct mtk_scp_of_cluster *scp_cluster)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev_of_node(dev);
> +	struct platform_device *cpdev;
> +	struct device_node *child;
> +	struct list_head *scp_list = &scp_cluster->mtk_scp_list;
> +	const struct mtk_scp_of_data **cluster_of_data;
> +	struct mtk_scp *scp, *temp;
> +	int core_id = 0;
> +	int ret;
> +
> +	cluster_of_data = (const struct mtk_scp_of_data **)of_device_get_match_data(dev);
> +
> +	for_each_available_child_of_node(np, child) {
> +		if (!cluster_of_data[core_id]) {
> +			ret = -EINVAL;
> +			dev_err(dev, "Not support core %d\n", core_id);
> +			of_node_put(child);
> +			goto init_fail;
> +		}
> +
> +		cpdev = of_find_device_by_node(child);
> +		if (!cpdev) {
> +			ret = -ENODEV;
> +			dev_err(dev, "Not found platform device for core %d\n", core_id);
> +			of_node_put(child);
> +			goto init_fail;
> +		}
> +
> +		scp = scp_rproc_init(cpdev, scp_cluster, cluster_of_data[core_id]);
> +		put_device(&cpdev->dev);
> +		if (IS_ERR(scp)) {
> +			ret = PTR_ERR(scp);
> +			dev_err(dev, "Failed to initialize core %d rproc\n", core_id);
> +			of_node_put(child);
> +			goto init_fail;
> +		}
> +
> +		ret = rproc_add(scp->rproc);
> +		if (ret) {
> +			dev_err(dev, "Failed to add rproc of core %d\n", core_id);
> +			of_node_put(child);
> +			scp_free(scp);
> +			goto init_fail;
> +		}
> +
> +		list_add_tail(&scp->elem, scp_list);
> +		core_id++;
> +	}
> +
> +	platform_set_drvdata(pdev, scp);
> +

Here we are setting the platform device for @pdev to the last @scp that was
created, which is needed because (1) scp_rproc_init() is calling
platform_set_drvdata() on the child platform devices and (2) we need a handle to
the cluster list in scp_remove().

Please add a comment with the above just before calling platform_set_drvdata().
Otherwise it will be very difficult for people not familiar with the driver to
understand what is going on.

Otherwise I think we are done.

Thanks,
Mathieu

> +	return 0;
> +
> +init_fail:
> +	list_for_each_entry_safe_reverse(scp, temp, scp_list, elem) {
> +		list_del(&scp->elem);
> +		rproc_del(scp->rproc);
> +		scp_free(scp);
> +	}
> +
> +	return ret;
> +}
> +
> +static int scp_is_single_core(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev_of_node(dev);
> +	struct device_node *child;
> +
> +	child = of_get_next_available_child(np, NULL);
> +	if (!child)
> +		return dev_err_probe(dev, -ENODEV, "No child node\n");
> +
> +	of_node_put(child);
> +	return of_node_name_eq(child, "cros-ec-rpmsg");
> +}
> +
> +static int scp_cluster_init(struct platform_device *pdev, struct mtk_scp_of_cluster *scp_cluster)
> +{
> +	int ret;
> +
> +	ret = scp_is_single_core(pdev);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (ret)
> +		ret = scp_add_single_core(pdev, scp_cluster);
> +	else
> +		ret = scp_add_multi_core(pdev, scp_cluster);
> +
> +	return ret;
> +}
> +
>  static int scp_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -1007,6 +1104,10 @@ static int scp_probe(struct platform_device *pdev)
>  
>  	INIT_LIST_HEAD(&scp_cluster->mtk_scp_list);
>  
> +	ret = devm_of_platform_populate(dev);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to populate platform devices\n");
> +
>  	ret = scp_cluster_init(pdev, scp_cluster);
>  	if (ret)
>  		return ret;
> @@ -1101,12 +1202,19 @@ static const struct mtk_scp_of_data mt8195_of_data_c1 = {
>  	.host_to_scp_int_bit = MT8195_CORE1_HOST_IPC_INT_BIT,
>  };
>  
> +static const struct mtk_scp_of_data *mt8195_of_data_cores[] = {
> +	&mt8195_of_data,
> +	&mt8195_of_data_c1,
> +	NULL
> +};
> +
>  static const struct of_device_id mtk_scp_of_match[] = {
>  	{ .compatible = "mediatek,mt8183-scp", .data = &mt8183_of_data },
>  	{ .compatible = "mediatek,mt8186-scp", .data = &mt8186_of_data },
>  	{ .compatible = "mediatek,mt8188-scp", .data = &mt8188_of_data },
>  	{ .compatible = "mediatek,mt8192-scp", .data = &mt8192_of_data },
>  	{ .compatible = "mediatek,mt8195-scp", .data = &mt8195_of_data },
> +	{ .compatible = "mediatek,mt8195-scp-dual", .data = &mt8195_of_data_cores },
>  	{},
>  };
>  MODULE_DEVICE_TABLE(of, mtk_scp_of_match);
> -- 
> 2.18.0
>