[RFC PATCH 43/77] dtc: Introduce dti_get_node_by_ref()

[Herve Codina <herve.codina@bootlin.com>]

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

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_ref().

dti_get_node_by_ref() retrieves a node by a reference (a label or a
path) like get_node_by_ref() 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 <herve.codina@bootlin.com>
---
 checks.c     | 10 ++++------
 dtc-parser.y | 22 +++++++++++++++++-----
 dtc.h        |  2 +-
 livetree.c   | 19 ++++++++++++++++---
 4 files changed, 38 insertions(+), 15 deletions(-)

diff --git a/checks.c b/checks.c
index fd22524..a47870d 100644
--- a/checks.c
+++ b/checks.c
@@ -486,7 +486,6 @@ ERROR(duplicate_label, check_duplicate_label_node, NULL);
 static cell_t check_phandle_prop(struct check *c, struct dt_info *dti,
 				 struct node *node, const char *propname)
 {
-	struct node *root = dti->dt;
 	struct property *prop;
 	struct marker *m;
 	cell_t phandle;
@@ -504,7 +503,7 @@ static cell_t check_phandle_prop(struct check *c, struct dt_info *dti,
 	m = prop->val.markers;
 	for_each_marker_of_type(m, REF_PHANDLE) {
 		assert(m->offset == 0);
-		if (node != get_node_by_ref(root, m->ref))
+		if (node != dti_get_node_by_ref(dti, m->ref))
 			/* "Set this node's phandle equal to some
 			 * other node's phandle".  That's nonsensical
 			 * by construction. */ {
@@ -614,7 +613,7 @@ static void fixup_phandle_references(struct check *c, struct dt_info *dti,
 		for_each_marker_of_type(m, REF_PHANDLE) {
 			assert(m->offset + sizeof(cell_t) <= prop->val.len);
 
-			refnode = get_node_by_ref(dt, m->ref);
+			refnode = dti_get_node_by_ref(dti, m->ref);
 			if (! refnode) {
 				if (!(dti->dtsflags & (DTSF_PLUGIN | DTSF_ADDON)))
 					FAIL(c, dti, node, "Reference to non-existent node or "
@@ -633,7 +632,7 @@ static void fixup_phandle_references(struct check *c, struct dt_info *dti,
 	}
 
 	for_each_symbol(node->exportsymlist, exportsym) {
-		refnode = get_node_by_ref(dt, exportsym->ref);
+		refnode = dti_get_node_by_ref(dti, exportsym->ref);
 		if (!refnode) {
 			if (!(dti->dtsflags & (DTSF_PLUGIN | DTSF_ADDON))) {
 				FAIL(c, dti, node,
@@ -657,7 +656,6 @@ ERROR(phandle_references, fixup_phandle_references, NULL,
 static void fixup_path_references(struct check *c, struct dt_info *dti,
 				  struct node *node)
 {
-	struct node *dt = dti->dt;
 	struct property *prop;
 
 	for_each_property(node, prop) {
@@ -668,7 +666,7 @@ static void fixup_path_references(struct check *c, struct dt_info *dti,
 		for_each_marker_of_type(m, REF_PATH) {
 			assert(m->offset <= prop->val.len);
 
-			refnode = get_node_by_ref(dt, m->ref);
+			refnode = dti_get_node_by_ref(dti, m->ref);
 			if (!refnode) {
 				FAIL(c, dti, node, "Reference to non-existent node or label \"%s\"\n",
 				     m->ref);
diff --git a/dtc-parser.y b/dtc-parser.y
index 61ebde2..08b3642 100644
--- a/dtc-parser.y
+++ b/dtc-parser.y
@@ -31,6 +31,18 @@ static bool is_ref_relative(const char *ref)
 	return ref[0] != '/' && strchr(&ref[1], '/');
 }
 
+static struct node *parser_get_node_by_ref(struct node *dt, const char *ref)
+{
+	/*
+	 * Use a temporary dt_info in order to use dti_get_node_by_ref()
+	 */
+	struct dt_info dti = {};
+
+	dti.dt = dt;
+
+	return dti_get_node_by_ref(&dti, ref);
+}
+
 %}
 
 %union {
@@ -240,7 +252,7 @@ devicetree:
 		}
 	| devicetree DT_LABEL dt_ref nodedef
 		{
-			struct node *target = get_node_by_ref($1, $3);
+			struct node *target = parser_get_node_by_ref($1, $3);
 
 			if ((last_header_flags & DTSF_PLUGIN) && is_ref_relative($3))
 				ERROR(&@2, "Label-relative reference %s not supported in plugin", $3);
@@ -259,7 +271,7 @@ devicetree:
 					ERROR(&@2, "Label-relative reference %s not supported in plugin", $2);
 				add_orphan_node($1, $3, $2);
 			} else {
-				struct node *target = get_node_by_ref($1, $2);
+				struct node *target = parser_get_node_by_ref($1, $2);
 
 				if (target)
 					merge_nodes(target, $3);
@@ -270,7 +282,7 @@ devicetree:
 		}
 	| devicetree DT_LABEL_REF nodedef
 		{
-			struct node *target = get_node_by_ref($1, $2);
+			struct node *target = parser_get_node_by_ref($1, $2);
 
 			if (target) {
 				merge_nodes(target, $3);
@@ -284,7 +296,7 @@ devicetree:
 		}
 	| devicetree DT_DEL_NODE dt_ref ';'
 		{
-			struct node *target = get_node_by_ref($1, $3);
+			struct node *target = parser_get_node_by_ref($1, $3);
 
 			if (target)
 				delete_node(target);
@@ -296,7 +308,7 @@ devicetree:
 		}
 	| devicetree DT_OMIT_NO_REF dt_ref ';'
 		{
-			struct node *target = get_node_by_ref($1, $3);
+			struct node *target = parser_get_node_by_ref($1, $3);
 
 			if (target)
 				omit_node_if_unused(target);
diff --git a/dtc.h b/dtc.h
index 7d53fcb..832265c 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_ref(struct node *tree, const char *ref);
 cell_t get_node_phandle(struct node *root, struct node *node);
 
 uint32_t guess_boot_cpuid(struct node *tree);
@@ -357,6 +356,7 @@ struct dt_info {
 struct node *dti_get_node_by_path(struct dt_info *dti, const char *path);
 struct node *dti_get_node_by_label(struct dt_info *dti, const char *label);
 struct node *dti_get_node_by_phandle(struct dt_info *dti, cell_t phandle);
+struct node *dti_get_node_by_ref(struct dt_info *dti, const char *ref);
 
 /* DTS version flags definitions */
 #define DTSF_V1		0x0001	/* /dts-v1/ */
diff --git a/livetree.c b/livetree.c
index a551307..f1c7e27 100644
--- a/livetree.c
+++ b/livetree.c
@@ -748,7 +748,7 @@ static struct node *get_node_by_phandle(struct node *tree, cell_t phandle)
 	return NULL;
 }
 
-struct node *get_node_by_ref(struct node *tree, const char *ref)
+static struct node *get_node_by_ref(struct node *tree, const char *ref)
 {
 	struct node *target = tree;
 	const char *label = NULL, *path = NULL;
@@ -824,6 +824,19 @@ struct node *dti_get_node_by_phandle(struct dt_info *dti, cell_t phandle)
 	return NULL;
 }
 
+struct node *dti_get_node_by_ref(struct dt_info *dti, const char *ref)
+{
+	struct node *node;
+
+	if (dti->dt) {
+		node = get_node_by_ref(dti->dt, ref);
+		if (node)
+			return node;
+	}
+
+	return NULL;
+}
+
 static void add_phandle_property(struct node *node,
 				 const char *name, int format)
 {
@@ -1407,7 +1420,7 @@ static void mark_local_phandles_internal(struct dt_info *dti,
 	for_each_property(node, prop) {
 		m = prop->val.markers;
 		for_each_marker_of_type(m, REF_PHANDLE) {
-			refnode = get_node_by_ref(dti->dt, m->ref);
+			refnode = dti_get_node_by_ref(dti, m->ref);
 			if (refnode)
 				m->is_local = true;
 		}
@@ -1460,7 +1473,7 @@ static void mark_local_exports_internal(struct dt_info *dti,
 	struct node *refnode;
 
 	for_each_symbol(node->exportsymlist, exportsym) {
-		refnode = get_node_by_ref(dti->dt, exportsym->ref);
+		refnode = dti_get_node_by_ref(dti, exportsym->ref);
 		if (refnode)
 			exportsym->is_local = true;
 	}
-- 
2.52.0