diff options
Diffstat (limited to 'drivers/pci')
| -rw-r--r-- | drivers/pci/Kconfig | 1 | ||||
| -rw-r--r-- | drivers/pci/Makefile | 1 | ||||
| -rw-r--r-- | drivers/pci/pwrctl/Kconfig | 8 | ||||
| -rw-r--r-- | drivers/pci/pwrctl/Makefile | 4 | ||||
| -rw-r--r-- | drivers/pci/pwrctl/core.c | 137 |
5 files changed, 151 insertions, 0 deletions
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig index d35001589d88..aa4d1833f442 100644 --- a/drivers/pci/Kconfig +++ b/drivers/pci/Kconfig @@ -296,5 +296,6 @@ source "drivers/pci/hotplug/Kconfig" source "drivers/pci/controller/Kconfig" source "drivers/pci/endpoint/Kconfig" source "drivers/pci/switch/Kconfig" +source "drivers/pci/pwrctl/Kconfig" endif diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile index 175302036890..8ddad57934a6 100644 --- a/drivers/pci/Makefile +++ b/drivers/pci/Makefile @@ -9,6 +9,7 @@ obj-$(CONFIG_PCI) += access.o bus.o probe.o host-bridge.o \ obj-$(CONFIG_PCI) += msi/ obj-$(CONFIG_PCI) += pcie/ +obj-$(CONFIG_PCI) += pwrctl/ ifdef CONFIG_PCI obj-$(CONFIG_PROC_FS) += proc.o diff --git a/drivers/pci/pwrctl/Kconfig b/drivers/pci/pwrctl/Kconfig new file mode 100644 index 000000000000..96195395af69 --- /dev/null +++ b/drivers/pci/pwrctl/Kconfig @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-2.0-only + +menu "PCI Power control drivers" + +config PCI_PWRCTL + tristate + +endmenu diff --git a/drivers/pci/pwrctl/Makefile b/drivers/pci/pwrctl/Makefile new file mode 100644 index 000000000000..52ae0640ef7b --- /dev/null +++ b/drivers/pci/pwrctl/Makefile @@ -0,0 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0-only + +obj-$(CONFIG_PCI_PWRCTL) += pci-pwrctl-core.o +pci-pwrctl-core-y := core.o diff --git a/drivers/pci/pwrctl/core.c b/drivers/pci/pwrctl/core.c new file mode 100644 index 000000000000..feca26ad2f6a --- /dev/null +++ b/drivers/pci/pwrctl/core.c @@ -0,0 +1,137 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2024 Linaro Ltd. + */ + +#include <linux/device.h> +#include <linux/export.h> +#include <linux/kernel.h> +#include <linux/pci.h> +#include <linux/pci-pwrctl.h> +#include <linux/property.h> +#include <linux/slab.h> + +static int pci_pwrctl_notify(struct notifier_block *nb, unsigned long action, + void *data) +{ + struct pci_pwrctl *pwrctl = container_of(nb, struct pci_pwrctl, nb); + struct device *dev = data; + + if (dev_fwnode(dev) != dev_fwnode(pwrctl->dev)) + return NOTIFY_DONE; + + switch (action) { + case BUS_NOTIFY_ADD_DEVICE: + /* + * We will have two struct device objects bound to two different + * drivers on different buses but consuming the same DT node. We + * must not bind the pins twice in this case but only once for + * the first device to be added. + * + * If we got here then the PCI device is the second after the + * power control platform device. Mark its OF node as reused. + */ + dev->of_node_reused = true; + break; + case BUS_NOTIFY_BOUND_DRIVER: + pwrctl->link = device_link_add(dev, pwrctl->dev, + DL_FLAG_AUTOREMOVE_CONSUMER); + if (!pwrctl->link) + dev_err(pwrctl->dev, "Failed to add device link\n"); + break; + case BUS_NOTIFY_UNBOUND_DRIVER: + if (pwrctl->link) + device_link_remove(dev, pwrctl->dev); + break; + } + + return NOTIFY_DONE; +} + +/** + * pci_pwrctl_device_set_ready() - Notify the pwrctl subsystem that the PCI + * device is powered-up and ready to be detected. + * + * @pwrctl: PCI power control data. + * + * Returns: + * 0 on success, negative error number on error. + * + * Note: + * This function returning 0 doesn't mean the device was detected. It means, + * that the bus rescan was successfully started. The device will get bound to + * its PCI driver asynchronously. + */ +int pci_pwrctl_device_set_ready(struct pci_pwrctl *pwrctl) +{ + int ret; + + if (!pwrctl->dev) + 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_unlock_rescan_remove(); + + return 0; +} +EXPORT_SYMBOL_GPL(pci_pwrctl_device_set_ready); + +/** + * pci_pwrctl_device_unset_ready() - Notify the pwrctl subsystem that the PCI + * device is about to be powered-down. + * + * @pwrctl: PCI power control data. + */ +void pci_pwrctl_device_unset_ready(struct pci_pwrctl *pwrctl) +{ + /* + * We don't have to delete the link here. Typically, this function + * is only called when the power control device is being detached. If + * it is being detached then the child PCI device must have already + * been unbound too or the device core wouldn't let us unbind. + */ + bus_unregister_notifier(&pci_bus_type, &pwrctl->nb); +} +EXPORT_SYMBOL_GPL(pci_pwrctl_device_unset_ready); + +static void devm_pci_pwrctl_device_unset_ready(void *data) +{ + struct pci_pwrctl *pwrctl = data; + + pci_pwrctl_device_unset_ready(pwrctl); +} + +/** + * devm_pci_pwrctl_device_set_ready - Managed variant of + * pci_pwrctl_device_set_ready(). + * + * @dev: Device managing this pwrctl provider. + * @pwrctl: PCI power control data. + * + * Returns: + * 0 on success, negative error number on error. + */ +int devm_pci_pwrctl_device_set_ready(struct device *dev, + struct pci_pwrctl *pwrctl) +{ + int ret; + + ret = pci_pwrctl_device_set_ready(pwrctl); + if (ret) + return ret; + + return devm_add_action_or_reset(dev, + devm_pci_pwrctl_device_unset_ready, + pwrctl); +} +EXPORT_SYMBOL_GPL(devm_pci_pwrctl_device_set_ready); + +MODULE_AUTHOR("Bartosz Golaszewski <bartosz.golaszewski@linaro.org>"); +MODULE_DESCRIPTION("PCI Device Power Control core driver"); +MODULE_LICENSE("GPL"); |