| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20251124-pci-pwrctrl-rework-v1-4-78a72627683d@oss.qualcomm.com>
Date: Mon, 24 Nov 2025 21:50:47 +0530
From: Manivannan Sadhasivam via B4 Relay <devnull+manivannan.sadhasivam.oss.qualcomm.com@...nel.org>
To: Manivannan Sadhasivam <mani@...nel.org>,
Lorenzo Pieralisi <lpieralisi@...nel.org>,
Krzysztof Wilczyński <kwilczynski@...nel.org>,
Rob Herring <robh@...nel.org>, Bjorn Helgaas <bhelgaas@...gle.com>,
Bartosz Golaszewski <brgl@...ev.pl>
Cc: linux-pci@...r.kernel.org, linux-arm-msm@...r.kernel.org,
linux-kernel@...r.kernel.org, Chen-Yu Tsai <wens@...nel.org>,
Brian Norris <briannorris@...omium.org>,
Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>,
Niklas Cassel <cassel@...nel.org>, Alex Elder <elder@...cstar.com>,
Manivannan Sadhasivam <manivannan.sadhasivam@....qualcomm.com>
Subject: [PATCH 4/5] PCI/pwrctrl: Add APIs to power on/off the pwrctrl
devices
From: Manivannan Sadhasivam <manivannan.sadhasivam@....qualcomm.com>
To fix PCIe bridge resource allocation issues when powering PCIe
switches with the pwrctrl driver, introduce APIs to explicitly power
on and off all related devices simultaneously.
Previously, the individual pwrctrl drivers powered on/off the PCIe devices
autonomously, without any control from the controller drivers. But to
enforce ordering w.r.t powering on the devices, these APIs will power
on/off all the devices at the same time.
The pci_pwrctrl_power_on_devices() API recursively scans the PCI child
nodes, makes sure that pwrctrl drivers are bind to devices, and calls their
power_on() callbacks.
Similarly, pci_pwrctrl_power_off_devices() API powers off devices
recursively via their power_off() callbacks.
These APIs are expected to be called during the controller probe and
suspend/resume time to power on/off the devices. But before calling these
APIs, the pwrctrl devices should've been created beforehand using the
pci_pwrctrl_{create/destroy}_devices() APIs.
Co-developed-by: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@....qualcomm.com>
---
drivers/pci/pwrctrl/core.c | 121 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/pci-pwrctrl.h | 4 ++
2 files changed, 125 insertions(+)
diff --git a/drivers/pci/pwrctrl/core.c b/drivers/pci/pwrctrl/core.c
index 6eca54e0d540..e0a0cf015bd0 100644
--- a/drivers/pci/pwrctrl/core.c
+++ b/drivers/pci/pwrctrl/core.c
@@ -65,6 +65,7 @@ void pci_pwrctrl_init(struct pci_pwrctrl *pwrctrl, struct device *dev)
{
pwrctrl->dev = dev;
INIT_WORK(&pwrctrl->work, rescan_work_func);
+ dev_set_drvdata(dev, pwrctrl);
}
EXPORT_SYMBOL_GPL(pci_pwrctrl_init);
@@ -152,6 +153,126 @@ int devm_pci_pwrctrl_device_set_ready(struct device *dev,
}
EXPORT_SYMBOL_GPL(devm_pci_pwrctrl_device_set_ready);
+static int __pci_pwrctrl_power_on_device(struct device *dev)
+{
+ struct pci_pwrctrl *pwrctrl = dev_get_drvdata(dev);
+
+ if (!pwrctrl)
+ return 0;
+
+ return pwrctrl->power_on(pwrctrl);
+}
+
+/*
+ * Power on the devices in a depth first manner. Before powering on the device,
+ * make sure its driver is bound.
+ */
+static int pci_pwrctrl_power_on_device(struct device_node *np)
+{
+ struct platform_device *pdev;
+ int ret;
+
+ for_each_available_child_of_node_scoped(np, child) {
+ ret = pci_pwrctrl_power_on_device(child);
+ if (ret)
+ return ret;
+ }
+
+ pdev = of_find_device_by_node(np);
+ if (pdev) {
+ if (!device_is_bound(&pdev->dev)) {
+ dev_err(&pdev->dev, "driver is not bound\n");
+ ret = -EPROBE_DEFER;
+ } else {
+ ret = __pci_pwrctrl_power_on_device(&pdev->dev);
+ }
+ put_device(&pdev->dev);
+
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+/**
+ * pci_pwrctrl_power_on_devices - Power on the pwrctrl devices
+ *
+ * @parent: Parent PCI device for which the pwrctrl devices need to be powered
+ * on.
+ *
+ * This function recursively traverses all pwrctrl devices for the child nodes
+ * of the specified PCI parent device, and powers them on in a depth first
+ * manner.
+ *
+ * Returns: 0 on success, negative error number on error.
+ */
+int pci_pwrctrl_power_on_devices(struct device *parent)
+{
+ struct device_node *np = parent->of_node;
+ int ret;
+
+ for_each_available_child_of_node_scoped(np, child) {
+ ret = pci_pwrctrl_power_on_device(child);
+ if (ret) {
+ pci_pwrctrl_power_off_devices(parent);
+ return ret;
+ }
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(pci_pwrctrl_power_on_devices);
+
+static void __pci_pwrctrl_power_off_device(struct device *dev)
+{
+ struct pci_pwrctrl *pwrctrl = dev_get_drvdata(dev);
+
+ if (!pwrctrl)
+ return;
+
+ return pwrctrl->power_off(pwrctrl);
+}
+
+static int pci_pwrctrl_power_off_device(struct device_node *np)
+{
+ struct platform_device *pdev;
+
+ for_each_available_child_of_node_scoped(np, child)
+ pci_pwrctrl_power_off_device(child);
+
+ pdev = of_find_device_by_node(np);
+ if (pdev) {
+ if (device_is_bound(&pdev->dev))
+ __pci_pwrctrl_power_off_device(&pdev->dev);
+
+ put_device(&pdev->dev);
+ }
+
+ return 0;
+}
+
+/**
+ * pci_pwrctrl_power_off_devices - Power off the pwrctrl devices
+ *
+ * @parent: Parent PCI device for which the pwrctrl devices need to be powered
+ * off.
+ *
+ * This function recursively traverses all pwrctrl devices for the child nodes
+ * of the specified PCI parent device, and powers them off in a depth first
+ * manner.
+ *
+ * Returns: 0 on success, negative error number on error.
+ */
+void pci_pwrctrl_power_off_devices(struct device *parent)
+{
+ struct device_node *np = parent->of_node;
+
+ for_each_available_child_of_node_scoped(np, child)
+ pci_pwrctrl_power_off_device(child);
+}
+EXPORT_SYMBOL_GPL(pci_pwrctrl_power_off_devices);
+
static int pci_pwrctrl_create_device(struct device_node *np, struct device *parent)
{
struct platform_device *pdev;
diff --git a/include/linux/pci-pwrctrl.h b/include/linux/pci-pwrctrl.h
index 5590ffec0bea..1b77769eebbe 100644
--- a/include/linux/pci-pwrctrl.h
+++ b/include/linux/pci-pwrctrl.h
@@ -57,8 +57,12 @@ int devm_pci_pwrctrl_device_set_ready(struct device *dev,
#if IS_ENABLED(CONFIG_PCI_PWRCTRL)
int pci_pwrctrl_create_devices(struct device *parent);
void pci_pwrctrl_destroy_devices(struct device *parent);
+int pci_pwrctrl_power_on_devices(struct device *parent);
+void pci_pwrctrl_power_off_devices(struct device *parent);
#else
static inline int pci_pwrctrl_create_devices(struct device *parent) { return 0; }
static void pci_pwrctrl_destroy_devices(struct device *parent) { }
+static inline int pci_pwrctrl_power_on_devices(struct device *parent) { return 0; }
+static void pci_pwrctrl_power_off_devices(struct device *parent) { }
#endif
#endif /* __PCI_PWRCTRL_H__ */
--
2.48.1
Powered by blists - more mailing lists