[Skiboot] [PATCH v13 4/9] dt: Add phandle fixup helpers

[Madhavan Srinivasan]

When there is a new device tree that needs to be added to
the main dt of the opal (ex, IMC catalog dtb loaded from
pnor partition), we need to check for the phandle values
in the new incoming device tree before attaching it.
Reason is that, incoming device tree could already have
phandle values initialized for its nodes. Now, if we attach
this new device tree to the main opal DT, we could
potentially hit phandle duplicate error (since the
phandles value usually start with 1).

To avoid this, a new helper function dt_adjust_subtree_phandle()
is added to scan the incoming device tree and update
node "phandle" accordingly based on the opal
"last_phandle" value.

Add to this, helper function also supports updates of
"properties" with in a node which may refer the
"phandle" value in the incoming device tree. Helper
function will also fix the "properties" field accordingly.

Signed-off-by: Madhavan Srinivasan <maddy at linux.vnet.ibm.com>
---
 core/device.c          | 38 ++++++++++++++++++++++++++++++++++++++
 core/test/run-device.c | 35 +++++++++++++++++++++++++++++++++--
 include/device.h       |  4 ++++
 3 files changed, 75 insertions(+), 2 deletions(-)

diff --git a/core/device.c b/core/device.c
index 7211570e1b3c..36b5d7b3637b 100644
--- a/core/device.c
+++ b/core/device.c
@@ -1069,3 +1069,41 @@ bool dt_node_is_enabled(struct dt_node *node)
 
 	return p->len > 1 && p->prop[0] == 'o' && p->prop[1] == 'k';
 }
+
+/*
+ * Function to fixup the phandle in the subtree.
+ */
+void dt_adjust_subtree_phandle(struct dt_node *dev,
+			const char** (get_properties_to_fix)(struct dt_node *n))
+{
+	struct dt_node *node;
+	struct dt_property *prop;
+	u32 phandle, max_phandle = 0, import_phandle = new_phandle();
+	const char **name;
+
+	dt_for_each_node(dev, node) {
+		const char **props_to_update;
+		node->phandle += import_phandle;
+
+		/*
+		 * calculate max_phandle(new_tree), needed to update
+		 * last_phandle.
+		 */
+		if (node->phandle >= max_phandle)
+			max_phandle = node->phandle;
+
+		props_to_update = get_properties_to_fix(node);
+		if (!props_to_update)
+			continue;
+		for (name = props_to_update; *name != NULL; name++) {
+			prop = __dt_find_property(node, *name);
+			if (!prop)
+				continue;
+			phandle = dt_prop_get_u32(node, *name);
+			phandle += import_phandle;
+			memcpy((char *)&prop->prop, &phandle, prop->len);
+		}
+       }
+
+       set_last_phandle(max_phandle);
+}
diff --git a/core/test/run-device.c b/core/test/run-device.c
index 5939afc70e54..1a4cb1edeaf5 100644
--- a/core/test/run-device.c
+++ b/core/test/run-device.c
@@ -33,6 +33,8 @@ static inline bool fake_is_rodata(const void *p)
 #include "../device.c"
 #include <assert.h>
 #include "../../test/dt_common.c"
+const char *prop_to_fix[] = {"something", NULL};
+const char **props_to_fix(struct dt_node *node);
 
 static void check_path(const struct dt_node *node, const char * expected_path)
 {
@@ -87,18 +89,29 @@ static bool is_sorted(const struct dt_node *root)
 	return true;
 }
 
+/*handler for phandle fixup test */
+const char **props_to_fix(struct dt_node *node)
+{
+	const struct dt_property *prop;
+
+	prop = dt_find_property(node, "something");
+	if (prop)
+		return prop_to_fix;
+
+	return NULL;
+}
 
 int main(void)
 {
 	struct dt_node *root, *c1, *c2, *gc1, *gc2, *gc3, *ggc1, *ggc2;
 	struct dt_node *addrs, *addr1, *addr2;
-	struct dt_node *i;
+	struct dt_node *i, *subtree, *ev1, *ut1, *ut2;
 	const struct dt_property *p;
 	struct dt_property *p2;
 	unsigned int n;
 	char *s;
 	size_t sz;
-	u32 phandle;
+	u32 phandle, ev1_ph, new_prop_ph;
 
 	root = dt_new_root("");
 	assert(!list_top(&root->properties, struct dt_property, list));
@@ -412,6 +425,24 @@ int main(void)
 
 	dt_free(root);
 
+	/* phandle fixup test */
+	subtree = dt_new_root("subtree");
+	ev1 = dt_new(subtree, "ev at 1");
+	ev1_ph = ev1->phandle;
+	dt_new(ev1,"a at 1");
+	dt_new(ev1,"a at 2");
+	dt_new(ev1,"a at 3");
+	ut1 = dt_new(subtree, "ut at 1");
+	dt_add_property(ut1, "something", (const void *)&ev1->phandle, 4);
+	ut2 = dt_new(subtree, "ut at 2");
+	dt_add_property(ut2, "something", (const void *)&ev1->phandle, 4);
+
+	dt_adjust_subtree_phandle(subtree, props_to_fix);
+	assert(!(ev1->phandle == ev1_ph));
+	new_prop_ph = dt_prop_get_u32(ut1, "something");
+	assert(!(new_prop_ph == ev1_ph));
+	new_prop_ph = dt_prop_get_u32(ut2, "something");
+	assert(!(new_prop_ph == ev1_ph));
 	return 0;
 }
 
diff --git a/include/device.h b/include/device.h
index c51b3eea298e..1e5875dca584 100644
--- a/include/device.h
+++ b/include/device.h
@@ -268,4 +268,8 @@ struct dt_node *__dt_find_by_name_addr(struct dt_node *parent, const char *name,
 struct dt_node *dt_find_by_name_addr(struct dt_node *parent, const char *name,
 				uint64_t addr);
 
+/* phandle fixup helper */
+void dt_adjust_subtree_phandle(struct dt_node *subtree,
+				const char** (get_properties_to_fix)(struct dt_node *n));
+
 #endif /* __DEVICE_H */
-- 
2.7.4