In some cases it makes sense to handle some phandles not as dependencies.
This is escpecially true for 'remote-endpoint' properties, because these
otherwise introducing dependency cycles into the graph. To avoid these,
one end of each remote-endpoint pairs has not to be handled as a
dependency.
The syntax is like
foo {
remote-endpoint = <&bar>;
};
bar {
remote-endpoint = <&foo>;
no-dependencies = <&foo>;
};
Without that 'no-dependencies' property dtc would automatically add a
dependency to foo to the property 'dependencies' of the node bar.
But with that 'no-dependencies' it will not automatically add the
listed dependencies.
The property 'no-dependencies' is virtual property and will not be added
to any output file.
Signed-off-by: Alexander Holler <holler@xxxxxxxxxxxxx>
---
scripts/dtc/dependencies.c | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)
diff --git a/scripts/dtc/dependencies.c b/scripts/dtc/dependencies.c
index 2c1e0d4..76e4d91 100644
--- a/scripts/dtc/dependencies.c
+++ b/scripts/dtc/dependencies.c
@@ -44,6 +44,23 @@ static bool is_parent_of(struct node *node1, struct node *node2)
}
+static bool is_no_dependency(struct node *dt, struct property *prop, cell_t ph)
+{
+ struct node *node;
+ unsigned i;
+ cell_t *cell = (cell_t *)(prop->val.val);
+
+ for (i = 0; i < prop->val.len/4; ++i) {
+ node = get_node_by_phandle(dt, cpu_to_fdt32(*cell++));
+ if (node) {
+ node = find_compatible_not_disabled(node);
+ if (node && get_node_phandle(dt, node) == ph)
+ return true;
+ }
+ }
+ return false;
+}
+
static void add_deps(struct node *dt, struct node *node, struct property *prop)
{
struct marker *m = prop->val.markers;
@@ -73,6 +90,10 @@ static void add_deps(struct node *dt, struct node *node, struct property *prop)
is_parent_of(target, source))
continue;
phandle = get_node_phandle(dt, target);
+ prop_deps = get_property(node, "no-dependencies");
+ if (prop_deps && is_no_dependency(dt, prop_deps, phandle))
+ /* avoid adding non-dependencies */
+ continue;
prop_deps = get_property(source, "dependencies");
if (!prop_deps) {
add_property(source,
@@ -102,9 +123,21 @@ static void process_nodes_props(struct node *dt, struct node *node)
process_nodes_props(dt, child);
}
+static void del_prop_no_dependencies(struct node *node)
+{
+ struct node *child;
+
+ if (!node)
+ return;
+ delete_property_by_name(node, "no-dependencies");
+ for_each_child(node, child)
+ del_prop_no_dependencies(child);
+}
+
void add_dependencies(struct boot_info *bi)
{
process_nodes_props(bi->dt, bi->dt);
+ del_prop_no_dependencies(bi->dt);
}
/*
--
2.1.0
--
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