Re: [RFC PATCH 40/77] dtc: Introduce dti_get_node_by_path()

David Gibson <[email protected]> Thu, 15 Jan 2026 17:47:29 +1100
Newsgroups	org.kernel.vger.devicetree-spec,org.kernel.vger.devicetree-compiler,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-kernel
Message-ID	<aWiNgZZ02-4jRc5l@zatzit>
On Mon, Jan 12, 2026 at 03:19:30PM +0100, Herve Codina wrote:
> The future introduction of orphan nodes for addons device-tree will lead
> to more than one tree in the addons data. Those trees will be:
>   - the classical root tree starting at the root node
>   - trees related to orphan nodes

This doesn't make sense to me.  The new function still just takes a
single path, nothing to specify which tree that path is looked up in.

You can probably guarantee that labels and phandles are unique across
all the trees.  Not paths, though.

> 
> Also, an addon device-tree can have only trees based on orphan nodes. In
> other words an addon device-tree is valid without having the classical
> 'root' tree.
> 
> To prepare this change, introduce and use dti_get_node_by_path().
> 
> dti_get_node_by_path() retrieves a node by its path like
> get_node_by_path() but it works at the struct dt_info level.
> 
> It handles the case where a 'root' device-tree is not present and will
> handle orphan nodes trees as soon as they will be introduced.
> 
> This introduction doesn't lead to any functional changes.
> 
> Signed-off-by: Herve Codina <[email protected]>
> ---
>  checks.c   |  2 +-
>  dtc.h      |  3 ++-
>  livetree.c | 15 ++++++++++++++-
>  3 files changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/checks.c b/checks.c
> index 9744431..b2b1bf7 100644
> --- a/checks.c
> +++ b/checks.c
> @@ -740,7 +740,7 @@ static void check_alias_paths(struct check *c, struct dt_info *dti,
>  
>  		/* This check does not work for overlays nor addons with external paths */
>  		if (!(dti->dtsflags & (DTSF_PLUGIN | DTSF_ADDON)) &&
> -		    (!prop->val.val || !get_node_by_path(dti->dt, prop->val.val))) {
> +		    (!prop->val.val || !dti_get_node_by_path(dti, prop->val.val))) {
>  			FAIL_PROP(c, dti, node, prop, "aliases property is not a valid node (%s)",
>  				  prop->val.val);
>  			continue;
> diff --git a/dtc.h b/dtc.h
> index 4ebe576..8ba093f 100644
> --- a/dtc.h
> +++ b/dtc.h
> @@ -323,7 +323,6 @@ struct property *get_property_by_label(struct node *tree, const char *label,
>  struct marker *get_marker_label(struct node *tree, const char *label,
>  				struct node **node, struct property **prop);
>  struct node *get_subnode(struct node *node, const char *nodename);
> -struct node *get_node_by_path(struct node *tree, const char *path);
>  struct node *get_node_by_label(struct node *tree, const char *label);
>  struct node *get_node_by_phandle(struct node *tree, cell_t phandle);
>  struct node *get_node_by_ref(struct node *tree, const char *ref);
> @@ -357,6 +356,8 @@ struct dt_info {
>  	const char *outname;		/* filename being written to, "-" for stdout */
>  };
>  
> +struct node *dti_get_node_by_path(struct dt_info *dti, const char *path);
> +
>  /* DTS version flags definitions */
>  #define DTSF_V1		0x0001	/* /dts-v1/ */
>  #define DTSF_PLUGIN	0x0002	/* /plugin/ */
> diff --git a/livetree.c b/livetree.c
> index 285f6e1..23ba957 100644
> --- a/livetree.c
> +++ b/livetree.c
> @@ -659,7 +659,7 @@ struct node *get_subnode(struct node *node, const char *nodename)
>  	return NULL;
>  }
>  
> -struct node *get_node_by_path(struct node *tree, const char *path)
> +static struct node *get_node_by_path(struct node *tree, const char *path)
>  {
>  	const char *p;
>  	struct node *child;
> @@ -785,6 +785,19 @@ struct node *get_node_by_ref(struct node *tree, const char *ref)
>  	return target;
>  }
>  
> +struct node *dti_get_node_by_path(struct dt_info *dti, const char *path)
> +{
> +	struct node *node;
> +
> +	if (dti->dt) {
> +		node = get_node_by_path(dti->dt, path);
> +		if (node)
> +			return node;
> +	}
> +
> +	return NULL;
> +}
> +
>  static void add_phandle_property(struct node *node,
>  				 const char *name, int format)
>  {
> -- 
> 2.52.0
> 
> 

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson
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