linux-kernel - [PATCH 2/2] of: property: fw_devlink: Fix links to supplier when created from phandles

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Date: Tue, 20 Feb 2024 12:10:37 +0100
From: Herve Codina <herve.codina@...tlin.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	Rob Herring <robh+dt@...nel.org>,
	Frank Rowand <frowand.list@...il.com>,
	Shawn Guo <shawnguo@...nel.org>,
	Saravana Kannan <saravanak@...gle.com>,
	Wolfram Sang <wsa@...nel.org>,
	Mark Brown <broonie@...nel.org>
Cc: Geert Uytterhoeven <geert+renesas@...der.be>,
	Rob Herring <robh@...nel.org>,
	linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org,
	Luca Ceresoli <luca.ceresoli@...tlin.com>,
	Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
	Herve Codina <herve.codina@...tlin.com>,
	stable@...r.kernel.org
Subject: [PATCH 2/2] of: property: fw_devlink: Fix links to supplier when created from phandles

Since commit 1a50d9403fb9 ("treewide: Fix probing of devices in DT
overlays"), when using device-tree overlays, the FWNODE_FLAG_NOT_DEVICE
is set on each overlay nodes. This flag is cleared when a struct device
is actually created for the DT node.
Also, when a device is created, the device DT node is parsed for known
phandle and devlinks consumer/supplier links are created between the
device (consumer) and the devices referenced by phandles (suppliers).
As these supplier device can have a struct device not already created,
the FWNODE_FLAG_NOT_DEVICE can be set for suppliers and leads the
devlink supplier point to the device's parent instead of the device
itself.

Avoid this situation clearing the supplier FWNODE_FLAG_NOT_DEVICE just
before the devlink creation if a device is supposed to be created and
handled later in the process.

Fixes: 1a50d9403fb9 ("treewide: Fix probing of devices in DT overlays")
Cc: <stable@...r.kernel.org>
Signed-off-by: Herve Codina <herve.codina@...tlin.com>
---
 drivers/of/property.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/of/property.c b/drivers/of/property.c
index 641a40cf5cf3..ff5cac477dbe 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -1097,6 +1097,7 @@ static void of_link_to_phandle(struct device_node *con_np,
 			      struct device_node *sup_np)
 {
 	struct device_node *tmp_np = of_node_get(sup_np);
+	struct fwnode_handle *sup_fwnode;
 
 	/* Check that sup_np and its ancestors are available. */
 	while (tmp_np) {
@@ -1113,7 +1114,20 @@ static void of_link_to_phandle(struct device_node *con_np,
 		tmp_np = of_get_next_parent(tmp_np);
 	}
 
-	fwnode_link_add(of_fwnode_handle(con_np), of_fwnode_handle(sup_np));
+	/*
+	 * In case of overlays, the fwnode are added with FWNODE_FLAG_NOT_DEVICE
+	 * flag set. A node can have a phandle that references an other node
+	 * added by the overlay.
+	 * Clear the supplier's FWNODE_FLAG_NOT_DEVICE so that fw_devlink links
+	 * to this supplier instead of linking to its parent.
+	 */
+	sup_fwnode = of_fwnode_handle(sup_np);
+	if (sup_fwnode->flags & FWNODE_FLAG_NOT_DEVICE) {
+		if (of_property_present(sup_np, "compatible") &&
+		    of_device_is_available(sup_np))
+			sup_fwnode->flags &= ~FWNODE_FLAG_NOT_DEVICE;
+	}
+	fwnode_link_add(of_fwnode_handle(con_np), sup_fwnode);
 }
 
 /**
-- 
2.43.0