126 lines
3.4 KiB
C
126 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* ARM System Control and Management Interface (ARM SCMI) reset driver
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*
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* Copyright (C) 2019 ARM Ltd.
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*/
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/device.h>
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#include <linux/reset-controller.h>
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#include <linux/scmi_protocol.h>
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/**
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* struct scmi_reset_data - reset controller information structure
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* @rcdev: reset controller entity
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* @handle: ARM SCMI handle used for communication with system controller
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*/
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struct scmi_reset_data {
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struct reset_controller_dev rcdev;
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const struct scmi_handle *handle;
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};
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#define to_scmi_reset_data(p) container_of((p), struct scmi_reset_data, rcdev)
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#define to_scmi_handle(p) (to_scmi_reset_data(p)->handle)
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/**
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* scmi_reset_assert() - assert device reset
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* @rcdev: reset controller entity
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* @id: ID of the reset to be asserted
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*
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* This function implements the reset driver op to assert a device's reset
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* using the ARM SCMI protocol.
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*
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* Return: 0 for successful request, else a corresponding error value
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*/
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static int
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scmi_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
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{
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const struct scmi_handle *handle = to_scmi_handle(rcdev);
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return handle->reset_ops->assert(handle, id);
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}
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/**
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* scmi_reset_deassert() - deassert device reset
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* @rcdev: reset controller entity
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* @id: ID of the reset to be deasserted
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*
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* This function implements the reset driver op to deassert a device's reset
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* using the ARM SCMI protocol.
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*
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* Return: 0 for successful request, else a corresponding error value
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*/
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static int
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scmi_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
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{
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const struct scmi_handle *handle = to_scmi_handle(rcdev);
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return handle->reset_ops->deassert(handle, id);
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}
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/**
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* scmi_reset_reset() - reset the device
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* @rcdev: reset controller entity
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* @id: ID of the reset signal to be reset(assert + deassert)
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*
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* This function implements the reset driver op to trigger a device's
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* reset signal using the ARM SCMI protocol.
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*
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* Return: 0 for successful request, else a corresponding error value
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*/
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static int
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scmi_reset_reset(struct reset_controller_dev *rcdev, unsigned long id)
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{
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const struct scmi_handle *handle = to_scmi_handle(rcdev);
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return handle->reset_ops->reset(handle, id);
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}
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static const struct reset_control_ops scmi_reset_ops = {
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.assert = scmi_reset_assert,
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.deassert = scmi_reset_deassert,
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.reset = scmi_reset_reset,
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};
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static int scmi_reset_probe(struct scmi_device *sdev)
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{
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struct scmi_reset_data *data;
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struct device *dev = &sdev->dev;
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struct device_node *np = dev->of_node;
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const struct scmi_handle *handle = sdev->handle;
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if (!handle || !handle->reset_ops)
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return -ENODEV;
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data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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data->rcdev.ops = &scmi_reset_ops;
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data->rcdev.owner = THIS_MODULE;
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data->rcdev.of_node = np;
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data->rcdev.nr_resets = handle->reset_ops->num_domains_get(handle);
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data->handle = handle;
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return devm_reset_controller_register(dev, &data->rcdev);
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}
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static const struct scmi_device_id scmi_id_table[] = {
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{ SCMI_PROTOCOL_RESET },
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{ },
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};
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MODULE_DEVICE_TABLE(scmi, scmi_id_table);
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static struct scmi_driver scmi_reset_driver = {
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.name = "scmi-reset",
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.probe = scmi_reset_probe,
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.id_table = scmi_id_table,
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};
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module_scmi_driver(scmi_reset_driver);
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MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
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MODULE_DESCRIPTION("ARM SCMI reset controller driver");
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MODULE_LICENSE("GPL v2");
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