Support ePAPR compliant phandle properties

Currently, the Linux kernel, libfdt and dtc, when using flattened
device trees encode a node's phandle into a property named
"linux,phandle".  The ePAPR specification, however - aiming as it is
to not be a Linux specific spec - requires that phandles be encoded in
a property named simply "phandle".

This patch adds support for this newer approach to dtc and libfdt.
Specifically:

	- fdt_get_phandle() will now return the correct phandle if it
          is supplied in either of these properties

	- fdt_node_offset_by_phandle() will correctly find a node with
          the given phandle encoded in either property.

	- By default, when auto-generating phandles, dtc will encode
          it into both properties for maximum compatibility.  A new -H
          option allows either only old-style or only new-style
          properties to be generated.

	- If phandle properties are explicitly supplied in the dts
	  file, dtc will not auto-generate ones in the alternate format.

	- If both properties are supplied, dtc will check that they
          have the same value.

	- Some existing testcases are updated to use a mix of old and
          new-style phandles, partially testing the changes.

	- A new phandle_format test further tests the libfdt support,
          and the -H option.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 20 insertions, 14 deletions

diff --git a/checks.c b/checks.c
index 35141f9..031cc59 100644
--- a/checks.c
+++ b/checks.c
@@ -279,20 +279,19 @@ static void check_property_name_chars(struct check *c, struct node *dt,
 PROP_CHECK(property_name_chars, PROPNODECHARS, ERROR);
 
 static void check_explicit_phandles(struct check *c, struct node *root,
-					  struct node *node)
+				    struct node *node, struct property *prop)
 {
-	struct property *prop;
 	struct marker *m;
 	struct node *other;
 	cell_t phandle;
 
-	prop = get_property(node, "linux,phandle");
-	if (! prop)
-		return; /* No phandle, that's fine */
+	if (!streq(prop->name, "phandle")
+	    && !streq(prop->name, "linux,phandle"))
+		return;
 
 	if (prop->val.len != sizeof(cell_t)) {
-		FAIL(c, "%s has bad length (%d) linux,phandle property",
-		     node->fullpath, prop->val.len);
+		FAIL(c, "%s has bad length (%d) %s property",
+		     node->fullpath, prop->val.len, prop->name);
 		return;
 	}
 
@@ -302,9 +301,11 @@ static void check_explicit_phandles(struct check *c, struct node *root,
 		if (node != get_node_by_ref(root, m->ref))
 			/* "Set this node's phandle equal to some
 			 * other node's phandle".  That's nonsensical
-			 * by construction. */
-			FAIL(c, "linux,phandle in %s is a reference to another node",
-			     node->fullpath);
+			 * by construction. */ {
+			FAIL(c, "%s in %s is a reference to another node",
+			     prop->name, node->fullpath);
+			return;
+		}
 		/* But setting this node's phandle equal to its own
 		 * phandle is allowed - that means allocate a unique
 		 * phandle for this node, even if it's not otherwise
@@ -314,14 +315,19 @@ static void check_explicit_phandles(struct check *c, struct node *root,
 	}
 
 	phandle = propval_cell(prop);
+
 	if ((phandle == 0) || (phandle == -1)) {
-		FAIL(c, "%s has invalid linux,phandle value 0x%x",
-		     node->fullpath, phandle);
+		FAIL(c, "%s has bad value (0x%x) in %s property",
+		     node->fullpath, phandle, prop->name);
 		return;
 	}
 
+	if (node->phandle && (node->phandle != phandle))
+		FAIL(c, "%s has %s property which replaces existing phandle information",
+		     node->fullpath, prop->name);
+
 	other = get_node_by_phandle(root, phandle);
-	if (other) {
+	if (other && (other != node)) {
 		FAIL(c, "%s has duplicated phandle 0x%x (seen before at %s)",
 		     node->fullpath, phandle, other->fullpath);
 		return;
@@ -329,7 +335,7 @@ static void check_explicit_phandles(struct check *c, struct node *root,
 
 	node->phandle = phandle;
 }
-NODE_CHECK(explicit_phandles, NULL, ERROR);
+PROP_CHECK(explicit_phandles, NULL, ERROR);
 
 static void check_name_properties(struct check *c, struct node *root,
 				  struct node *node)