[RFC] Allow device tree to be modified by additonal device tree sections
Grant Likely
grant.likely at secretlab.ca
Wed Feb 24 06:28:13 EST 2010
This patch allows the following construct:
/ {
property-a = "old";
property-b = "does not change";
};
/ {
property-a = "changed";
property-c = "new";
node-a {
};
};
Where the later device tree overrides the properties found in the
earlier tree. This is useful for laying down a template device tree
in an include file and modifying it for a specific board without having
to clone the entire tree.
Signed-off-by: Grant Likely <grant.likely at secretlab.ca>
---
I haven't extensively tested this patch yet, and I haven't figured out yet
how to properly write the test cases, but I want to get this out there to
make sure I'm taking the right approach.
Cheers,
g.
dtc-parser.y | 14 ++++++++-
dtc.h | 1 +
livetree.c | 63 ++++++++++++++++++++++++++++++++++++++++
tests/redefine-nodes-test1.dts | 8 +++++
tests/redefine-nodes-test2.dts | 9 ++++++
tests/redefine-nodes-test3.dts | 9 ++++++
tests/redefine-nodes-test4.dts | 11 +++++++
tests/redefine-nodes-test5.dts | 9 ++++++
tests/redefine-nodes-test6.dts | 11 +++++++
tests/redefine-nodes-test7.dts | 13 ++++++++
10 files changed, 147 insertions(+), 1 deletions(-)
create mode 100644 tests/redefine-nodes-test1.dts
create mode 100644 tests/redefine-nodes-test2.dts
create mode 100644 tests/redefine-nodes-test3.dts
create mode 100644 tests/redefine-nodes-test4.dts
create mode 100644 tests/redefine-nodes-test5.dts
create mode 100644 tests/redefine-nodes-test6.dts
create mode 100644 tests/redefine-nodes-test7.dts
diff --git a/dtc-parser.y b/dtc-parser.y
index bd9e097..8f5c4a3 100644
--- a/dtc-parser.y
+++ b/dtc-parser.y
@@ -75,6 +75,7 @@ static unsigned long long eval_literal(const char *s, int base, int bits);
%type <proplist> proplist
%type <node> devicetree
+%type <node> devicetrees
%type <node> nodedef
%type <node> subnode
%type <nodelist> subnodes
@@ -83,7 +84,7 @@ static unsigned long long eval_literal(const char *s, int base, int bits);
%%
sourcefile:
- DT_V1 ';' memreserves devicetree
+ DT_V1 ';' memreserves devicetrees
{
the_boot_info = build_boot_info($3, $4,
guess_boot_cpuid($4));
@@ -115,6 +116,17 @@ addr:
}
;
+devicetrees:
+ /* empty */
+ {
+ $$ = NULL;
+ }
+ | devicetree devicetrees
+ {
+ $$ = merge_nodes($1, $2);
+ }
+ ;
+
devicetree:
'/' nodedef
{
diff --git a/dtc.h b/dtc.h
index 5367198..815494a 100644
--- a/dtc.h
+++ b/dtc.h
@@ -164,6 +164,7 @@ struct property *reverse_properties(struct property *first);
struct node *build_node(struct property *proplist, struct node *children);
struct node *name_node(struct node *node, char *name, char *label);
struct node *chain_node(struct node *first, struct node *list);
+struct node *merge_nodes(struct node *old_node, struct node *new_node);
void add_property(struct node *node, struct property *prop);
void add_child(struct node *parent, struct node *child);
diff --git a/livetree.c b/livetree.c
index aa0edf1..0691599 100644
--- a/livetree.c
+++ b/livetree.c
@@ -89,6 +89,69 @@ struct node *name_node(struct node *node, char *name, char * label)
return node;
}
+struct node *merge_nodes(struct node *old_node, struct node *new_node)
+{
+ struct property *new_prop, *old_prop;
+ struct node *new_child, *old_child;
+
+ printf("Merge node, old_node:%s new_node:%s\n", old_node->name,
+ new_node ? new_node->name : "<NULL>" );
+ if (!new_node)
+ return old_node;
+
+ /* Move the override properties into the old node. If there
+ * is a collision, replace the old definition with the new */
+ while (new_node->proplist) {
+ /* Pop the property off the list */
+ new_prop = new_node->proplist;
+ new_node->proplist = new_prop->next;
+ new_prop->next = NULL;
+
+ /* Look for a collision, set new value if there is */
+ for_each_property(old_node, old_prop) {
+ if (strcmp(old_prop->name, new_prop->name) == 0) {
+ old_prop->val = new_prop->val;
+ free(new_prop);
+ new_prop = NULL;
+ break;
+ }
+ }
+
+ /* Assuming no collision, add the property to the old node. */
+ if (new_prop)
+ add_property(old_node, new_prop);
+ }
+
+ /* Move the override child nodes into the primary node. If
+ * there is a collision, then merge the nodes. */
+ while (new_node->children) {
+ /* Pop the child node off the list */
+ new_child = new_node->children;
+ new_node->children = new_child->next_sibling;
+ new_child->parent = NULL;
+ new_child->next_sibling = NULL;
+
+ /* Search for a collision. Merge if there is */
+ for_each_child(old_node, old_child) {
+ if (strcmp(old_child->name, new_child->name) == 0) {
+ merge_nodes(old_child, new_child);
+ new_child = NULL;
+ break;
+ }
+ }
+
+ /* Assuming no collision, add the child to the old node. */
+ if (new_child)
+ add_child(old_node, new_child);
+ }
+
+ /* The new node contents are now merged into the old node. Free
+ * the new node. */
+ free(new_node);
+
+ return old_node;
+}
+
struct node *chain_node(struct node *first, struct node *list)
{
assert(first->next_sibling == NULL);
diff --git a/tests/redefine-nodes-test1.dts b/tests/redefine-nodes-test1.dts
new file mode 100644
index 0000000..a9ccaa2
--- /dev/null
+++ b/tests/redefine-nodes-test1.dts
@@ -0,0 +1,8 @@
+/dts-v1/;
+
+/ {
+};
+
+/ {
+ prop = "new";
+};
diff --git a/tests/redefine-nodes-test2.dts b/tests/redefine-nodes-test2.dts
new file mode 100644
index 0000000..9e0b55e
--- /dev/null
+++ b/tests/redefine-nodes-test2.dts
@@ -0,0 +1,9 @@
+/dts-v1/;
+
+/ {
+ prop = "old";
+};
+
+/ {
+ prop = "new";
+};
diff --git a/tests/redefine-nodes-test3.dts b/tests/redefine-nodes-test3.dts
new file mode 100644
index 0000000..cb135f3
--- /dev/null
+++ b/tests/redefine-nodes-test3.dts
@@ -0,0 +1,9 @@
+/dts-v1/;
+
+/ {
+ prop1 = "old";
+};
+
+/ {
+ prop2 = "new";
+};
diff --git a/tests/redefine-nodes-test4.dts b/tests/redefine-nodes-test4.dts
new file mode 100644
index 0000000..a331c62
--- /dev/null
+++ b/tests/redefine-nodes-test4.dts
@@ -0,0 +1,11 @@
+/dts-v1/;
+
+/ {
+ prop1 = "olda";
+ prop2 = "oldb";
+ prop3 = "oldc";
+};
+
+/ {
+ prop2 = "new";
+};
diff --git a/tests/redefine-nodes-test5.dts b/tests/redefine-nodes-test5.dts
new file mode 100644
index 0000000..b12de06
--- /dev/null
+++ b/tests/redefine-nodes-test5.dts
@@ -0,0 +1,9 @@
+/dts-v1/;
+
+/ {
+};
+
+/ {
+ subnode {
+ };
+};
diff --git a/tests/redefine-nodes-test6.dts b/tests/redefine-nodes-test6.dts
new file mode 100644
index 0000000..de05b49
--- /dev/null
+++ b/tests/redefine-nodes-test6.dts
@@ -0,0 +1,11 @@
+/dts-v1/;
+
+/ {
+ subnode {
+ };
+};
+
+/ {
+ subnode {
+ };
+};
diff --git a/tests/redefine-nodes-test7.dts b/tests/redefine-nodes-test7.dts
new file mode 100644
index 0000000..7b9ab92
--- /dev/null
+++ b/tests/redefine-nodes-test7.dts
@@ -0,0 +1,13 @@
+/dts-v1/;
+
+/ {
+ subnode {
+ prop1 = "val1";
+ };
+};
+
+/ {
+ subnode {
+ prop2 = "val2";
+ };
+};
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