[Pdbg] [PATCH v2 07/22] libpdbg: Create virtual nodes based on system-path property

[Amitay Isaacs]

To create a virtual node, "system-path" property is used to denote the
attachment point in the system device tree view.

It's also possible to create virtual nodes from backend device tree as
nodes without compatible property.

All nodes without "compatible" property will be treated as virtual
nodes.

Signed-off-by: Amitay Isaacs <amitay at ozlabs.org>
---
 libpdbg/device.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)

diff --git a/libpdbg/device.c b/libpdbg/device.c
index 9cb2a0a..77eac21 100644
--- a/libpdbg/device.c
+++ b/libpdbg/device.c
@@ -649,6 +649,88 @@ uint64_t pdbg_target_address(struct pdbg_target *target, uint64_t *out_size)
 	return dt_get_number(p->prop, na);
 }
 
+static struct pdbg_target *dt_new_virtual(struct pdbg_target *root, const char *system_path)
+{
+	char *parent_path, *sep;
+	struct pdbg_target *parent, *vnode;
+
+	parent_path = strdup(system_path);
+	assert(parent_path);
+
+	sep = strrchr(parent_path, '/');
+	if (!sep || sep[1] == '\0') {
+		PR_ERROR("Invalid path reference \"%s\"\n", system_path);
+		free(parent_path);
+		return NULL;
+	}
+
+	*sep = '\0';
+
+	parent = dt_find_by_path(root, parent_path);
+	if (!parent) {
+		PR_ERROR("Invalid path reference \"%s\"\n", system_path);
+		free(parent_path);
+		return NULL;
+	}
+
+	vnode = dt_new_node(sep+1, NULL, 0);
+	assert(vnode);
+
+	free(parent_path);
+
+	if (!dt_attach_node(parent, vnode)) {
+		free(vnode);
+		return NULL;
+	}
+
+	PR_DEBUG("Created virtual node %s\n", system_path);
+	return vnode;
+}
+
+static void pdbg_targets_init_virtual(struct pdbg_target *node, struct pdbg_target *root)
+{
+	struct pdbg_target *vnode, *child = NULL;
+	struct dt_property *prop;
+	const char *system_path;
+	size_t len;
+
+	system_path = (const char *)pdbg_target_property(node, "system-path", &len);
+	if (!system_path)
+		goto skip;
+
+	/*
+	 * If the virtual node exists,
+	 *   - if it is already linked, skip
+	 *   - else link the node
+	 */
+	vnode = dt_find_by_path(root, system_path);
+	if (vnode) {
+		if (vnode->vnode)
+			goto skip;
+		else
+			goto link_vnode;
+	}
+
+	vnode = dt_new_virtual(root, system_path);
+	if (!vnode)
+		goto skip;
+
+link_vnode:
+	node->vnode = vnode;
+	vnode->vnode = node;
+
+	while ((prop = list_pop(&vnode->properties, struct dt_property, list)))
+		list_add_tail(&node->properties, &prop->list);
+
+skip:
+	list_for_each(&node->children, child, list) {
+		if (child->vnode && !child->compatible)
+			continue;
+
+		pdbg_targets_init_virtual(child, root);
+	}
+}
+
 void pdbg_targets_init(void *fdt)
 {
 	/* Root node needs to be valid when this function returns */
@@ -663,6 +745,7 @@ void pdbg_targets_init(void *fdt)
 	}
 
 	dt_expand(pdbg_dt_root, fdt);
+	pdbg_targets_init_virtual(pdbg_dt_root, pdbg_dt_root);
 }
 
 char *pdbg_target_path(struct pdbg_target *target)
-- 
2.21.0