[PATCH 1/4] of: fall back to parent-prefixed encoding when address translation fails

[Sascha Hauer]

of_get_reproducible_name() formatted the result of of_translate_address()
as [0x%llx] without checking for OF_BAD_ADDR ((u64)-1). For any node
whose reg can't be translated through the parent's ranges - notably PCI
child nodes whose reg[0] encodes a config-space address (space=0), which
host bridges don't list in ranges - this produced [0xffffffffffffffff]
for every such node, collapsing distinct nodes onto the same name and
making of_find_node_by_reproducible_name() return the wrong sibling.

Fall through to the existing parent-prefixed {offset} branch when
translation fails, so untranslatable siblings get disambiguated by
their parent chain.

Assisted-by: Claude Opus 4.7
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 drivers/of/base.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 5297894f60..1244664827 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -3368,7 +3368,14 @@ char *of_get_reproducible_name(struct device_node *node)
 
 	if (node->parent && of_get_property(node->parent, "ranges", NULL)) {
 		addr = of_translate_address(node, reg);
-		return basprintf("[0x%llx]", addr);
+		if (addr != OF_BAD_ADDR)
+			return basprintf("[0x%llx]", addr);
+		/*
+		 * Untranslatable - e.g. a PCI config-space address whose
+		 * tag (space=0) doesn't appear in the parent's ranges.
+		 * Fall through to the parent-prefixed encoding so distinct
+		 * untranslatable nodes don't all collide on OF_BAD_ADDR.
+		 */
 	}
 
 	na = of_n_addr_cells(node);

-- 
2.47.3