[Pdbg] [PATCH v4 12/30] libpdbg: Create virtual nodes based on system-path property

[Alistair Popple]

Reviewed-by: Alistair Popple <alistair at popple.id.au>

On Thursday, 3 October 2019 2:18:51 PM AEDT Amitay Isaacs wrote:
> 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.
> 
> If a virtual node is mapped to a real node, then copy any properties
> (except #address-cells and #size-cells) to the real node.
> 
> Signed-off-by: Amitay Isaacs <amitay at ozlabs.org>
> ---
>  libpdbg/device.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 97 insertions(+)
> 
> diff --git a/libpdbg/device.c b/libpdbg/device.c
> index 2f3d677..d7cd980 100644
> --- a/libpdbg/device.c
> +++ b/libpdbg/device.c
> @@ -651,6 +651,102 @@ 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 dt_link_virtual(struct pdbg_target *node, struct pdbg_target *vnode)
> +{
> +	struct dt_property *prop = NULL, *next;
> +
> +	node->vnode = vnode;
> +	vnode->vnode = node;
> +
> +	/* Move any properties on virtual node to real node */
> +	list_for_each_safe(&vnode->properties, prop, next, list) {
> +		if (!strcmp(prop->name, "#address-cells") || !strcmp(prop->name, "#size-cells"))
> +			continue;
> +
> +		list_del(&prop->list);
> +		list_add_tail(&node->properties, &prop->list);
> +	}
> +}
> +
> +static void pdbg_targets_init_virtual(struct pdbg_target *node, struct pdbg_target *root)
> +{
> +	struct pdbg_target *vnode, *child = NULL;
> +	const char *system_path;
> +	size_t len;
> +
> +	system_path = (const char *)pdbg_target_property(node, "system-path", &len);
> +	if (!system_path)
> +		goto skip;
> +
> +	/*
> +	 * A virtual node identifies the attachment point of a node in the
> +	 * system tree.
> +	 */
> +	vnode = dt_find_by_path(root, system_path);
> +	if (!vnode)
> +		vnode = dt_new_virtual(root, system_path);
> +
> +	/* If virtual node does not exist, or cannot be created, skip */
> +	if (!vnode)
> +		goto skip;
> +
> +	assert(target_is_virtual(vnode));
> +
> +	/*
> +	 * If virtual node is not linked, then link with node;
> +	 * otherwise skip
> +	 */
> +	if (!vnode->vnode)
> +		dt_link_virtual(node, vnode);
> +
> +skip:
> +	list_for_each(&node->children, child, list) {
> +		/* If a virtual node is already linked, skip */
> +		if (target_is_virtual(child) && child->vnode)
> +			continue;
> +
> +		pdbg_targets_init_virtual(child, root);
> +	}
> +}
> +
>  void pdbg_targets_init(void *fdt)
>  {
>  	/* Root node needs to be valid when this function returns */
> @@ -665,6 +761,7 @@ 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)
>