2024-06-12 01:20:17 -07:00
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2024 Linaro Ltd.
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*/
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#include <linux/device.h>
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#include <linux/export.h>
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#include <linux/kernel.h>
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#include <linux/pci.h>
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#include <linux/pci-pwrctl.h>
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#include <linux/property.h>
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#include <linux/slab.h>
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static int pci_pwrctl_notify(struct notifier_block *nb, unsigned long action,
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void *data)
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{
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struct pci_pwrctl *pwrctl = container_of(nb, struct pci_pwrctl, nb);
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struct device *dev = data;
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if (dev_fwnode(dev) != dev_fwnode(pwrctl->dev))
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return NOTIFY_DONE;
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switch (action) {
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case BUS_NOTIFY_ADD_DEVICE:
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/*
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* We will have two struct device objects bound to two different
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* drivers on different buses but consuming the same DT node. We
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* must not bind the pins twice in this case but only once for
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* the first device to be added.
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*
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* If we got here then the PCI device is the second after the
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* power control platform device. Mark its OF node as reused.
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*/
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dev->of_node_reused = true;
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break;
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case BUS_NOTIFY_BOUND_DRIVER:
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pwrctl->link = device_link_add(dev, pwrctl->dev,
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DL_FLAG_AUTOREMOVE_CONSUMER);
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if (!pwrctl->link)
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dev_err(pwrctl->dev, "Failed to add device link\n");
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break;
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case BUS_NOTIFY_UNBOUND_DRIVER:
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if (pwrctl->link)
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device_link_remove(dev, pwrctl->dev);
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break;
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}
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return NOTIFY_DONE;
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}
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2024-08-23 02:33:23 -07:00
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static void rescan_work_func(struct work_struct *work)
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{
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struct pci_pwrctl *pwrctl = container_of(work, struct pci_pwrctl, work);
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pci_lock_rescan_remove();
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pci_rescan_bus(to_pci_dev(pwrctl->dev->parent)->bus);
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pci_unlock_rescan_remove();
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}
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/**
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* pci_pwrctl_init() - Initialize the PCI power control context struct
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*
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* @pwrctl: PCI power control data
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* @dev: Parent device
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*/
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void pci_pwrctl_init(struct pci_pwrctl *pwrctl, struct device *dev)
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{
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pwrctl->dev = dev;
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INIT_WORK(&pwrctl->work, rescan_work_func);
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}
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EXPORT_SYMBOL_GPL(pci_pwrctl_init);
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2024-06-12 01:20:17 -07:00
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/**
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* pci_pwrctl_device_set_ready() - Notify the pwrctl subsystem that the PCI
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* device is powered-up and ready to be detected.
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*
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* @pwrctl: PCI power control data.
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*
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* Returns:
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* 0 on success, negative error number on error.
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*
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* Note:
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* This function returning 0 doesn't mean the device was detected. It means,
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* that the bus rescan was successfully started. The device will get bound to
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* its PCI driver asynchronously.
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*/
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int pci_pwrctl_device_set_ready(struct pci_pwrctl *pwrctl)
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{
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int ret;
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if (!pwrctl->dev)
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return -ENODEV;
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pwrctl->nb.notifier_call = pci_pwrctl_notify;
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ret = bus_register_notifier(&pci_bus_type, &pwrctl->nb);
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if (ret)
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return ret;
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2024-08-23 02:33:23 -07:00
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schedule_work(&pwrctl->work);
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2024-06-12 01:20:17 -07:00
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return 0;
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}
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EXPORT_SYMBOL_GPL(pci_pwrctl_device_set_ready);
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/**
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* pci_pwrctl_device_unset_ready() - Notify the pwrctl subsystem that the PCI
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* device is about to be powered-down.
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*
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* @pwrctl: PCI power control data.
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*/
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void pci_pwrctl_device_unset_ready(struct pci_pwrctl *pwrctl)
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{
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/*
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* We don't have to delete the link here. Typically, this function
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* is only called when the power control device is being detached. If
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* it is being detached then the child PCI device must have already
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* been unbound too or the device core wouldn't let us unbind.
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*/
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bus_unregister_notifier(&pci_bus_type, &pwrctl->nb);
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}
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EXPORT_SYMBOL_GPL(pci_pwrctl_device_unset_ready);
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static void devm_pci_pwrctl_device_unset_ready(void *data)
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{
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struct pci_pwrctl *pwrctl = data;
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pci_pwrctl_device_unset_ready(pwrctl);
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}
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/**
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* devm_pci_pwrctl_device_set_ready - Managed variant of
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* pci_pwrctl_device_set_ready().
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*
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* @dev: Device managing this pwrctl provider.
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* @pwrctl: PCI power control data.
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*
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* Returns:
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* 0 on success, negative error number on error.
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*/
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int devm_pci_pwrctl_device_set_ready(struct device *dev,
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struct pci_pwrctl *pwrctl)
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{
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int ret;
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ret = pci_pwrctl_device_set_ready(pwrctl);
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if (ret)
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return ret;
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return devm_add_action_or_reset(dev,
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devm_pci_pwrctl_device_unset_ready,
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pwrctl);
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}
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EXPORT_SYMBOL_GPL(devm_pci_pwrctl_device_set_ready);
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MODULE_AUTHOR("Bartosz Golaszewski <bartosz.golaszewski@linaro.org>");
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MODULE_DESCRIPTION("PCI Device Power Control core driver");
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MODULE_LICENSE("GPL");
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