[PATCH v3] Allow device tree to be modified by additonal device tree sections
Grant Likely
grant.likely at secretlab.ca
Fri Feb 26 03:58:29 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>
---
Changes since RFC (v1):
- Fix parser to ensure at least one 'devicetree' section
- merge labels too
- Don't change property value if property already has a value and
the redefinition is in the form of an empty property
ie: 'label: property;'
- Add test cases
Changes since v2:
- Revert code that doesn't change property value if the redefinition
is in the form of an empty property
- Improvements to test cases
dtc-parser.y | 14 ++++++++
dtc.h | 1 +
livetree.c | 75 +++++++++++++++++++++++++++++++++++++++++++-
tests/multilabel.dts | 12 +++++--
tests/multilabel_merge.dts | 66 +++++++++++++++++++++++++++++++++++++++
tests/run_tests.sh | 7 ++++
tests/test_tree1_merge.dts | 45 ++++++++++++++++++++++++++
7 files changed, 214 insertions(+), 6 deletions(-)
create mode 100644 tests/multilabel_merge.dts
create mode 100644 tests/test_tree1_merge.dts
diff --git a/dtc-parser.y b/dtc-parser.y
index 8fa1e4f..dea19c1 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
@@ -82,7 +83,7 @@ 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));
@@ -119,6 +120,17 @@ addr:
}
;
+devicetrees:
+ devicetree
+ {
+ $$ = $1;
+ }
+ | devicetrees devicetree
+ {
+ $$ = merge_nodes($1, $2);
+ }
+ ;
+
devicetree:
'/' nodedef
{
diff --git a/dtc.h b/dtc.h
index 6d61b6d..b36ac5d 100644
--- a/dtc.h
+++ b/dtc.h
@@ -174,6 +174,7 @@ 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);
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 f612b72..13c5f10 100644
--- a/livetree.c
+++ b/livetree.c
@@ -26,8 +26,14 @@
void add_label(struct label **labels, char *label)
{
- struct label *new = xmalloc(sizeof(*new));
+ struct label *new;
+ /* Make sure the label isn't already there */
+ for_each_label(*labels, new)
+ if (streq(new->label, label))
+ return;
+
+ new = xmalloc(sizeof(*new));
new->label = label;
new->next = *labels;
*labels = new;
@@ -94,6 +100,73 @@ struct node *name_node(struct node *node, char *name)
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;
+ struct label *l;
+
+ /* Add new node labels to old node */
+ for_each_label(new_node->labels, l)
+ add_label(&old_node->labels, l->label);
+
+ /* Move properties from the new node to the old node. If there
+ * is a collision, replace the old value 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 (streq(old_prop->name, new_prop->name)) {
+ /* Add new labels to old property */
+ for_each_label(new_prop->labels, l)
+ add_label(&old_prop->labels, l->label);
+
+ old_prop->val = new_prop->val;
+ free(new_prop);
+ new_prop = NULL;
+ break;
+ }
+ }
+
+ /* if no collision occurred, add 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 (streq(old_child->name, new_child->name)) {
+ merge_nodes(old_child, new_child);
+ new_child = NULL;
+ break;
+ }
+ }
+
+ /* if no collision occured, add 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/multilabel.dts b/tests/multilabel.dts
index 87c175c..31116ce 100644
--- a/tests/multilabel.dts
+++ b/tests/multilabel.dts
@@ -3,26 +3,27 @@
m1: mq: /memreserve/ 0 0x1000;
/ {
- p1: px: prop = "foo";
+ p0: pw: prop = "foo";
/* Explicit phandles */
n1: nx: node1 {
linux,phandle = <0x2000>;
ref = <&{/node2}>; /* reference precedes target */
- lref = <&ny>;
+ p1: px: lref = <&ny>;
};
ny: n2: node2 {
- phandle = <0x1>;
+ p2: py: phandle = <0x1>;
ref = <&{/node1}>; /* reference after target */
lref = <&nx>;
};
/* Implicit phandles */
n3: node3 {
- ref = <&{/node4}>;
+ p3: ref = <&{/node4}>;
lref = <&n4>;
};
n4: node4 {
+ p4: prop;
};
/* Explicit phandle with implicit value */
@@ -34,5 +35,8 @@ m1: mq: /memreserve/ 0 0x1000;
n5: nz: node5 {
linux,phandle = <&n5>;
phandle = <&nz>;
+ n1 = &n1;
+ n2 = &n2;
+ n3 = &n3;
};
};
diff --git a/tests/multilabel_merge.dts b/tests/multilabel_merge.dts
new file mode 100644
index 0000000..1632300
--- /dev/null
+++ b/tests/multilabel_merge.dts
@@ -0,0 +1,66 @@
+/dts-v1/;
+
+m1: mq: /memreserve/ 0 0x1000;
+
+/ {
+ p0: pw: prop = "foo";
+
+ /* Explicit phandles */
+ n1: node1 {
+ linux,phandle = <0x2000>;
+ ref = <&{/node2}>; /* reference precedes target */
+ p1: lref;
+ };
+ node2 {
+ phandle = <0x1>;
+ ref = <&{/node1}>; /* reference after target */
+ lref = <&nx>;
+ };
+
+ /* Implicit phandles */
+ n3: node3 {
+ p3: ref = <&{/node4}>;
+ lref = <&n4>;
+ };
+ n4: node4 {
+ p4: prop = "foo";
+ };
+
+ /* Explicit phandle with implicit value */
+ /* This self-reference is the standard way to tag a node as requiring
+ * a phandle (perhaps for reference by nodes that will be dynamically
+ * added) without explicitly allocating it a phandle.
+ * The self-reference requires some special internal handling, though
+ * so check it actually works */
+ n5: nz: node5 {
+ linux,phandle = <&n5>;
+ phandle = <&nz>;
+ n1 = &n1;
+ n2 = &n2;
+ n3 = &n3;
+ };
+};
+
+/ {
+ /* Append labels (also changes property content) */
+ nx: node1 {
+ px: lref = <&ny>;
+ };
+
+ /* Add multiple labels */
+ ny: n2: node2 {
+ /* Add a label to a property */
+ p2: py: phandle = <0x1>;
+ };
+
+ /* Reassigning the same label should be a no-op */
+ n3: node3 {
+ p3: ref = <&{/node4}>;
+ };
+
+ /* Redefining a node/property should not remove labels */
+ node4 {
+ prop;
+ };
+
+};
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index 08535ad..43b9d44 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -297,6 +297,13 @@ dtc_tests () {
done
done
+ # Check merge/overlay functionality
+ run_dtc_test -I dts -O dtb -o dtc_tree1_merge.test.dtb test_tree1_merge.dts
+ tree1_tests dtc_tree1_merge.test.dtb test_tree1.dtb
+ run_dtc_test -I dts -O dtb -o multilabel_merge.test.dtb multilabel_merge.dts
+ run_test references multilabel.test.dtb
+ run_test dtbs_equal_ordered multilabel.test.dtb multilabel_merge.test.dtb
+
# Check some checks
check_tests dup-nodename.dts duplicate_node_names
check_tests dup-propname.dts duplicate_property_names
diff --git a/tests/test_tree1_merge.dts b/tests/test_tree1_merge.dts
new file mode 100644
index 0000000..f580da8
--- /dev/null
+++ b/tests/test_tree1_merge.dts
@@ -0,0 +1,45 @@
+/dts-v1/;
+/memreserve/ 0xdeadbeef00000000 0x100000;
+/memreserve/ 123456789 010000;
+
+/ {
+ compatible = "test_tree1";
+ prop-int = "wrong!";
+ prop-str = "hello world";
+
+ subnode at 1 {
+ compatible = "subnode1";
+
+ subsubnode {
+ compatible = "subsubnode1", "subsubnode";
+ prop-int = <0xdeadbeef>;
+ };
+
+ ss1 {
+ };
+ };
+
+ subnode at 2 {
+ linux,phandle = <0x2000>;
+ prop-int = <123456789>;
+
+ ss2 {
+ };
+ };
+};
+
+/ {
+ prop-int = <0xdeadbeef>;
+ subnode at 1 {
+ prop-int = [deadbeef];
+ };
+ subnode at 2 {
+ subsubnode at 0 {
+ phandle = <0x2001>;
+ compatible = "subsubnode2", "subsubnode";
+ prop-int = <0726746425>;
+ };
+ };
+};
+
+
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