linux-kernel - [PATCH v3 2/2] PCI: of: Attach created of

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Date: Mon, 25 Mar 2024 16:39:15 +0100
From: Herve Codina <herve.codina@...tlin.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Lizhi Hou <lizhi.hou@....com>,
	Rob Herring <robh@...nel.org>
Cc: Max Zhen <max.zhen@....com>,
	Sonal Santan <sonal.santan@....com>,
	Stefano Stabellini <stefano.stabellini@...inx.com>,
	Jonathan Cameron <Jonathan.Cameron@...wei.com>,
	Krzysztof Wilczyński <kwilczynski@...nel.org>,
	linux-kernel@...r.kernel.org,
	linux-pci@...r.kernel.org,
	Allan Nielsen <allan.nielsen@...rochip.com>,
	Horatiu Vultur <horatiu.vultur@...rochip.com>,
	Steen Hegelund <steen.hegelund@...rochip.com>,
	Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
	Herve Codina <herve.codina@...tlin.com>,
	stable@...r.kernel.org
Subject: [PATCH v3 2/2] PCI: of: Attach created of_node to existing device

The commit 407d1a51921e ("PCI: Create device tree node for bridge")
creates of_node for PCI devices.

During the insertion handling of these new DT nodes done by of_platform,
new devices (struct device) are created. For each PCI devices a struct
device is already present (created and handled by the PCI core).
Having a second struct device to represent the exact same PCI device is
not correct.

On the of_node creation:
- tell the of_platform that there is no need to create a device for this
  node (OF_POPULATED flag),
- link this newly created of_node to the already present device,
- tell fwnode that the device attached to this of_node is ready using
  fwnode_dev_initialized().

With this fix, the of_node are available in the sysfs device tree:
/sys/devices/platform/soc/d0070000.pcie/
+ of_node -> .../devicetree/base/soc/pcie@...70000
+ pci0000:00
  + 0000:00:00.0
    + of_node -> .../devicetree/base/soc/pcie@...70000/pci@0,0
    + 0000:01:00.0
      + of_node -> .../devicetree/base/soc/pcie@...70000/pci@0,0/dev@0,0

On the of_node removal, revert the operations.

Fixes: 407d1a51921e ("PCI: Create device tree node for bridge")
Cc: stable@...r.kernel.org
Signed-off-by: Herve Codina <herve.codina@...tlin.com>
---
 drivers/pci/of.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index 51e3dd0ea5ab..5afd2731e876 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -615,7 +615,8 @@ void of_pci_remove_node(struct pci_dev *pdev)
 	np = pci_device_to_OF_node(pdev);
 	if (!np || !of_node_check_flag(np, OF_DYNAMIC))
 		return;
-	pdev->dev.of_node = NULL;
+
+	device_remove_of_node(&pdev->dev);
 
 	of_changeset_revert(np->data);
 	of_changeset_destroy(np->data);
@@ -668,12 +669,22 @@ void of_pci_make_dev_node(struct pci_dev *pdev)
 	if (ret)
 		goto out_free_node;
 
+	/*
+	 * This of_node will be added to an existing device.
+	 * Avoid any device creation and use the existing device
+	 */
+	of_node_set_flag(np, OF_POPULATED);
+	np->fwnode.dev = &pdev->dev;
+	fwnode_dev_initialized(&np->fwnode, true);
+
 	ret = of_changeset_apply(cset);
 	if (ret)
 		goto out_free_node;
 
 	np->data = cset;
-	pdev->dev.of_node = np;
+
+	/* Add the of_node to the existing device */
+	device_add_of_node(&pdev->dev, np);
 	kfree(name);
 
 	return;
-- 
2.44.0