[PATCH] remoteproc: mediatek: Refactor single core check and fix retrocompatibility

[Mathieu Poirier]

On Tue, Sep 19, 2023 at 11:23:36AM +0200, AngeloGioacchino Del Regno wrote:
> In older devicetrees we had the ChromeOS EC in a node called "cros-ec"
> instead of the newer "cros-ec-rpmsg", but this driver is now checking
> only for the latter, breaking compatibility with those.
> 
> Besides, we can check if the SCP is single or dual core by simply
> walking through the children of the main SCP node and checking if
> if there's more than one "mediatek,scp-core" compatible node.
> 
> Fixes: 1fdbf0cdde98 ("remoteproc: mediatek: Probe SCP cluster on multi-core SCP")
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
> ---
>  drivers/remoteproc/mtk_scp.c | 18 +++++++-----------
>  1 file changed, 7 insertions(+), 11 deletions(-)
> 

I find this patch to be the most appropriate to fix this problem.  Laura,
Chen-Yu and Tinghan, please test the patch and reply public with your Testeb-by
tags.

Thanks,
Mathieu

> diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c
> index ea227b566c54..a35409eda0cf 100644
> --- a/drivers/remoteproc/mtk_scp.c
> +++ b/drivers/remoteproc/mtk_scp.c
> @@ -1144,29 +1144,25 @@ static int scp_add_multi_core(struct platform_device *pdev,
>  	return ret;
>  }
>  
> -static int scp_is_single_core(struct platform_device *pdev)
> +static bool 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;
> +	int num_cores = 0;
>  
> -	child = of_get_next_available_child(np, NULL);
> -	if (!child)
> -		return dev_err_probe(dev, -ENODEV, "No child node\n");
> +	for_each_child_of_node(np, child)
> +		if (of_device_is_compatible(child, "mediatek,scp-core"))
> +			num_cores++;
>  
> -	of_node_put(child);
> -	return of_node_name_eq(child, "cros-ec-rpmsg");
> +	return num_cores < 2;
>  }
>  
>  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)
> +	if (scp_is_single_core(pdev))
>  		ret = scp_add_single_core(pdev, scp_cluster);
>  	else
>  		ret = scp_add_multi_core(pdev, scp_cluster);
> -- 
> 2.42.0
>