linux-kernel - [PATCH RFC 3/7] pci: Change the parent of the platform devices for child OF nodes

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Date: Wed, 26 Jun 2024 18:07:51 +0530
From: Krishna chaitanya chundru <quic_krichai@...cinc.com>
To: Bartosz Golaszewski <brgl@...ev.pl>,
        Manivannan Sadhasivam
	<manivannan.sadhasivam@...aro.org>,
        Lorenzo Pieralisi
	<lpieralisi@...nel.org>,
        Krzysztof Wilczyński
	<kw@...ux.com>,
        Rob Herring <robh@...nel.org>, Bjorn Helgaas
	<bhelgaas@...gle.com>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley
	<conor+dt@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio
	<konrad.dybcio@...aro.org>,
        Jingoo Han <jingoohan1@...il.com>
CC: <quic_vbadigan@...cinc.com>, <quic_skananth@...cinc.com>,
        <quic_nitegupt@...cinc.com>, <linux-arm-msm@...r.kernel.org>,
        <linux-pci@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        Krishna chaitanya chundru
	<quic_krichai@...cinc.com>
Subject: [PATCH RFC 3/7] pci: Change the parent of the platform devices for
 child OF nodes

Currently the power control driver is child of pci-pci bridge driver,
this will cause issue when suspend resume is introduced in the pwr
control driver. If the supply is removed to the endpoint in the
power control driver then the config space access initaited by the
pci-pci bridge driver can cause issues like Timeouts.

For this reason change the parent to controller from pci-pci bridge.
Signed-off-by: Krishna chaitanya chundru <quic_krichai@...cinc.com>
---
 drivers/pci/bus.c         | 5 +++--
 drivers/pci/pwrctl/core.c | 7 ++++++-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 3e3517567721..eedab4aabd81 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -335,6 +335,7 @@ void __weak pcibios_bus_add_device(struct pci_dev *pdev) { }
 void pci_bus_add_device(struct pci_dev *dev)
 {
 	struct device_node *dn = dev->dev.of_node;
+	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
 	int retval;
 
 	/*
@@ -356,9 +357,9 @@ void pci_bus_add_device(struct pci_dev *dev)
 
 	pci_dev_assign_added(dev, true);
 
-	if (pci_is_bridge(dev)) {
+	if (pci_is_bridge(dev) && host) {
 		retval = of_platform_populate(dev->dev.of_node, NULL, NULL,
-					      &dev->dev);
+					      host->dev.parent);
 		if (retval)
 			pci_err(dev, "failed to populate child OF nodes (%d)\n",
 				retval);
diff --git a/drivers/pci/pwrctl/core.c b/drivers/pci/pwrctl/core.c
index feca26ad2f6a..4c0d0f3b15f8 100644
--- a/drivers/pci/pwrctl/core.c
+++ b/drivers/pci/pwrctl/core.c
@@ -10,6 +10,7 @@
 #include <linux/pci-pwrctl.h>
 #include <linux/property.h>
 #include <linux/slab.h>
+#include "../pci.h"
 
 static int pci_pwrctl_notify(struct notifier_block *nb, unsigned long action,
 			     void *data)
@@ -64,18 +65,22 @@ static int pci_pwrctl_notify(struct notifier_block *nb, unsigned long action,
  */
 int pci_pwrctl_device_set_ready(struct pci_pwrctl *pwrctl)
 {
+	struct pci_bus *bus = pci_find_bus(of_get_pci_domain_nr(pwrctl->dev->parent->of_node), 0);
 	int ret;
 
 	if (!pwrctl->dev)
 		return -ENODEV;
 
+	if (!bus)
+		return -ENODEV;
+
 	pwrctl->nb.notifier_call = pci_pwrctl_notify;
 	ret = bus_register_notifier(&pci_bus_type, &pwrctl->nb);
 	if (ret)
 		return ret;
 
 	pci_lock_rescan_remove();
-	pci_rescan_bus(to_pci_dev(pwrctl->dev->parent)->bus);
+	pci_rescan_bus(bus);
 	pci_unlock_rescan_remove();
 
 	return 0;

-- 
2.42.0