linux-kernel - [PATCH v3 1/2] PCI: don't rely on of_platform

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Message-ID: <20240823093323.33450-2-brgl@bgdev.pl>
Date: Fri, 23 Aug 2024 11:33:22 +0200
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Bjorn Helgaas <bhelgaas@...gle.com>,
	Krishna chaitanya chundru <quic_krichai@...cinc.com>,
	Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
Cc: linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: [PATCH v3 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 | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 910387e5bdbf..4770cb87e3f0 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -1,7 +1,10 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/pci.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
 #include "pci.h"
 
 static void pci_free_resources(struct pci_dev *dev)
@@ -14,12 +17,25 @@ static void pci_free_resources(struct pci_dev *dev)
 	}
 }
 
+static int pci_pwrctl_unregister(struct device *dev, void *data)
+{
+	struct device_node *pci_node = data, *plat_node = dev_of_node(dev);
+
+	if (dev_is_platform(dev) && plat_node && plat_node == pci_node) {
+		of_device_unregister(to_platform_device(dev));
+		of_node_clear_flag(plat_node, OF_POPULATED);
+	}
+
+	return 0;
+}
+
 static void pci_stop_dev(struct pci_dev *dev)
 {
 	pci_pme_active(dev, false);
 
 	if (pci_dev_is_added(dev)) {
-		of_platform_depopulate(&dev->dev);
+		device_for_each_child(dev->dev.parent, dev_of_node(&dev->dev),
+				      pci_pwrctl_unregister);
 		device_release_driver(&dev->dev);
 		pci_proc_detach_device(dev);
 		pci_remove_sysfs_dev_files(dev);
-- 
2.43.0