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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Bjorn Andersson , Konrad Dybcio , Catalin Marinas , Will Deacon , Bjorn Helgaas , Heiko Stuebner , Jernej Skrabec , Chris Morgan , Linus Walleij , Geert Uytterhoeven , Arnd Bergmann , Neil Armstrong , =?utf-8?q?N=C3=ADcolas_F_=2E_R_?= =?utf-8?q?=2E_A_=2E_Prado?= , Marek Szyprowski , Peng Fan , Robert Richter , Dan Williams , Jonathan Cameron , Terry Bowman , Lukas Wunner , Huacai Chen , Alex Elder , Srini Kandagatla , Greg Kroah-Hartman , Abel Vesa Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, Bartosz Golaszewski Subject: [PATCH 6/9] PCI/pwrseq: add pwrseq core code Date: Wed, 17 Jan 2024 17:07:45 +0100 Message-Id: <20240117160748.37682-7-brgl@bgdev.pl> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20240117160748.37682-1-brgl@bgdev.pl> References: <20240117160748.37682-1-brgl@bgdev.pl> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Bartosz Golaszewski Some PCI devices must be powered-on before they can be detected on the bus. Introduce a simple framework reusing the existing PCI OF infrastructure. The way this works is: a DT node representing a PCI device connected to the port can be matched against its power sequencing platform driver. If the match succeeds, the driver is responsible for powering-up the device and calling pcie_pwrseq_device_enable() which will trigger a PCI bus rescan as well as subscribe to PCI bus notifications. When the device is detected and created, we'll make it consume the same DT node that the platform device did. When the device is bound, we'll create a device link between it and the parent power sequencing device. Signed-off-by: Bartosz Golaszewski --- drivers/pci/Kconfig | 1 + drivers/pci/Makefile | 1 + drivers/pci/pwrseq/Kconfig | 8 ++++ drivers/pci/pwrseq/Makefile | 3 ++ drivers/pci/pwrseq/pwrseq.c | 82 +++++++++++++++++++++++++++++++++++++ include/linux/pci-pwrseq.h | 24 +++++++++++ 6 files changed, 119 insertions(+) create mode 100644 drivers/pci/pwrseq/Kconfig create mode 100644 drivers/pci/pwrseq/Makefile create mode 100644 drivers/pci/pwrseq/pwrseq.c create mode 100644 include/linux/pci-pwrseq.h diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig index 74147262625b..e0fd5caa1ffc 100644 --- a/drivers/pci/Kconfig +++ b/drivers/pci/Kconfig @@ -291,5 +291,6 @@ source "drivers/pci/hotplug/Kconfig" source "drivers/pci/controller/Kconfig" source "drivers/pci/endpoint/Kconfig" source "drivers/pci/switch/Kconfig" +source "drivers/pci/pwrseq/Kconfig" endif diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile index cc8b4e01e29d..0a1673ef2c9e 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) += pwrseq/ ifdef CONFIG_PCI obj-$(CONFIG_PROC_FS) += proc.o diff --git a/drivers/pci/pwrseq/Kconfig b/drivers/pci/pwrseq/Kconfig new file mode 100644 index 000000000000..a721a8a955c3 --- /dev/null +++ b/drivers/pci/pwrseq/Kconfig @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-2.0 + +menu "PCI Power sequencing drivers" + +config PCI_PWRSEQ + bool + +endmenu diff --git a/drivers/pci/pwrseq/Makefile b/drivers/pci/pwrseq/Makefile new file mode 100644 index 000000000000..4052b6bb5aa5 --- /dev/null +++ b/drivers/pci/pwrseq/Makefile @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0 + +obj-$(CONFIG_PCI_PWRSEQ) += pwrseq.o diff --git a/drivers/pci/pwrseq/pwrseq.c b/drivers/pci/pwrseq/pwrseq.c new file mode 100644 index 000000000000..a750c7bc6830 --- /dev/null +++ b/drivers/pci/pwrseq/pwrseq.c @@ -0,0 +1,82 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2024 Linaro Ltd. + */ + +#include +#include +#include +#include +#include +#include +#include + +static int pci_pwrseq_notify(struct notifier_block *nb, unsigned long action, + void *data) +{ + struct pci_pwrseq *pwrseq = container_of(nb, struct pci_pwrseq, nb); + struct device *dev = data; + + if (dev_fwnode(dev) != dev_fwnode(pwrseq->dev)) + return NOTIFY_DONE; + + switch (action) { + case BUS_NOTIFY_ADD_DEVICE: + device_set_of_node_from_dev(dev, pwrseq->dev); + break; + case BUS_NOTIFY_BOUND_DRIVER: + pwrseq->link = device_link_add(dev, pwrseq->dev, + DL_FLAG_AUTOREMOVE_CONSUMER); + if (!pwrseq->link) + dev_err(pwrseq->dev, "Failed to add device link\n"); + break; + case BUS_NOTIFY_UNBOUND_DRIVER: + device_link_del(pwrseq->link); + break; + } + + return NOTIFY_DONE; +} + +int pci_pwrseq_device_enable(struct pci_pwrseq *pwrseq) +{ + if (!pwrseq->dev) + return -ENODEV; + + pwrseq->nb.notifier_call = pci_pwrseq_notify; + bus_register_notifier(&pci_bus_type, &pwrseq->nb); + + pci_lock_rescan_remove(); + pci_rescan_bus(to_pci_dev(pwrseq->dev->parent)->bus); + pci_unlock_rescan_remove(); + + return 0; +} +EXPORT_SYMBOL_GPL(pci_pwrseq_device_enable); + +void pci_pwrseq_device_disable(struct pci_pwrseq *pwrseq) +{ + bus_unregister_notifier(&pci_bus_type, &pwrseq->nb); +} +EXPORT_SYMBOL_GPL(pci_pwrseq_device_disable); + +static void devm_pci_pwrseq_device_disable(void *data) +{ + struct pci_pwrseq *pwrseq = data; + + pci_pwrseq_device_disable(pwrseq); +} + +int devm_pci_pwrseq_device_enable(struct device *dev, + struct pci_pwrseq *pwrseq) +{ + int ret; + + ret = pci_pwrseq_device_enable(pwrseq); + if (ret) + return ret; + + return devm_add_action_or_reset(dev, devm_pci_pwrseq_device_disable, + pwrseq); +} +EXPORT_SYMBOL_GPL(devm_pci_pwrseq_device_enable); diff --git a/include/linux/pci-pwrseq.h b/include/linux/pci-pwrseq.h new file mode 100644 index 000000000000..137b82b99d1c --- /dev/null +++ b/include/linux/pci-pwrseq.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (C) 2024 Linaro Ltd. + */ + +#ifndef __PCI_PWRSEQ_H__ +#define __PCI_PWRSEQ_H__ + +#include + +struct device; + +struct pci_pwrseq { + struct notifier_block nb; + struct device *dev; + struct device_link *link; +}; + +int pci_pwrseq_device_enable(struct pci_pwrseq *pwrseq); +void pci_pwrseq_device_disable(struct pci_pwrseq *pwrseq); +int devm_pci_pwrseq_device_enable(struct device *dev, + struct pci_pwrseq *pwrseq); + +#endif /* __PCI_PWRSEQ_H__ */