linux-kernel - [PATCH 1/2] PCI: don't rely on of_platform

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Message-ID: <20240813191119.155103-2-brgl@bgdev.pl>
Date: Tue, 13 Aug 2024 21:11:17 +0200
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Bjorn Helgaas <bhelgaas@...gle.com>
Cc: linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: [PATCH 1/2] PCI: don't rely on of_platform_depopulate() for reused OF-nodes

From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>

of_platform_depopulate() doesn't play nice with reused OF nodes - it
ignores the ones that are not marked explicitly as populated and it may
happen that the PCI device goes away before the platform device in which
case the PCI core clears the OF_POPULATED bit. We need to
unconditionally unregister the platform devices for child nodes when
stopping the PCI device.

Fixes: 8fb18619d910 ("PCI/pwrctl: Create platform devices for child OF nodes of the port node")
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
---
 drivers/pci/remove.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 910387e5bdbf..7d78d0c0b7e2 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/pci.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/of_platform.h>
 #include "pci.h"
 
@@ -16,13 +17,26 @@ static void pci_free_resources(struct pci_dev *dev)
 
 static void pci_stop_dev(struct pci_dev *dev)
 {
+	struct platform_device *pdev;
+	struct device_node *child;
+
 	pci_pme_active(dev, false);
 
 	if (pci_dev_is_added(dev)) {
-		of_platform_depopulate(&dev->dev);
 		device_release_driver(&dev->dev);
 		pci_proc_detach_device(dev);
 		pci_remove_sysfs_dev_files(dev);
+
+		if (dev_of_node(&dev->dev)) {
+			for_each_child_of_node(dev_of_node(&dev->dev), child) {
+				pdev = of_find_device_by_node(child);
+				if (pdev) {
+					of_device_unregister(pdev);
+					of_node_clear_flag(child, OF_POPULATED);
+				}
+			}
+		}
+
 		of_pci_remove_node(dev);
 
 		pci_dev_assign_added(dev, false);
-- 
2.43.0