drivers/reset/reset-ti-sci.c - linux - Git at Google

 /*
  * Texas Instrument's System Control Interface (TI-SCI) reset driver
  *
  * Copyright (C) 2015-2017 Texas Instruments Incorporated - https://www.ti.com/
  *	Andrew F. Davis <afd@ti.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  * kind, whether express or implied; without even the implied warranty
  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */

 #include <linux/idr.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/reset-controller.h>
 #include <linux/soc/ti/ti_sci_protocol.h>

 /**
  * struct ti_sci_reset_control - reset control structure
  * @dev_id: SoC-specific device identifier
  * @reset_mask: reset mask to use for toggling reset
  * @lock: synchronize reset_mask read-modify-writes
  */
 struct ti_sci_reset_control {
 	u32 dev_id;
 	u32 reset_mask;
 	struct mutex lock;
 };

 /**
  * struct ti_sci_reset_data - reset controller information structure
  * @rcdev: reset controller entity
  * @dev: reset controller device pointer
  * @sci: TI SCI handle used for communication with system controller
  * @idr: idr structure for mapping ids to reset control structures
  */
 struct ti_sci_reset_data {
 	struct reset_controller_dev rcdev;
 	struct device *dev;
 	const struct ti_sci_handle *sci;
 	struct idr idr;
 };

 #define to_ti_sci_reset_data(p)	\
 	container_of((p), struct ti_sci_reset_data, rcdev)

 /**
  * ti_sci_reset_set() - program a device's reset
  * @rcdev: reset controller entity
  * @id: ID of the reset to toggle
  * @assert: boolean flag to indicate assert or deassert
  *
  * This is a common internal function used to assert or deassert a device's
  * reset using the TI SCI protocol. The device's reset is asserted if the
  * @assert argument is true, or deasserted if @assert argument is false.
  * The mechanism itself is a read-modify-write procedure, the current device
  * reset register is read using a TI SCI device operation, the new value is
  * set or un-set using the reset's mask, and the new reset value written by
  * using another TI SCI device operation.
  *
  * Return: 0 for successful request, else a corresponding error value
  */
 static int ti_sci_reset_set(struct reset_controller_dev *rcdev,
 			    unsigned long id, bool assert)
 {
 	struct ti_sci_reset_data *data = to_ti_sci_reset_data(rcdev);
 	const struct ti_sci_handle *sci = data->sci;
 	const struct ti_sci_dev_ops *dev_ops = &sci->ops.dev_ops;
 	struct ti_sci_reset_control *control;
 	u32 reset_state;
 	int ret;

 	control = idr_find(&data->idr, id);
 	if (!control)
 		return -EINVAL;

 	mutex_lock(&control->lock);

 	ret = dev_ops->get_device_resets(sci, control->dev_id, &reset_state);
 	if (ret)
 		goto out;

 	if (assert)
 		reset_state |= control->reset_mask;
 	else
 		reset_state &= ~control->reset_mask;

 	ret = dev_ops->set_device_resets(sci, control->dev_id, reset_state);
 out:
 	mutex_unlock(&control->lock);

 	return ret;
 }

 /**
  * ti_sci_reset_assert() - assert device reset
  * @rcdev: reset controller entity
  * @id: ID of the reset to be asserted
  *
  * This function implements the reset driver op to assert a device's reset
  * using the TI SCI protocol. This invokes the function ti_sci_reset_set()
  * with the corresponding parameters as passed in, but with the @assert
  * argument set to true for asserting the reset.
  *
  * Return: 0 for successful request, else a corresponding error value
  */
 static int ti_sci_reset_assert(struct reset_controller_dev *rcdev,
 			       unsigned long id)
 {
 	return ti_sci_reset_set(rcdev, id, true);
 }

 /**
  * ti_sci_reset_deassert() - deassert device reset
  * @rcdev: reset controller entity
  * @id: ID of the reset to be deasserted
  *
  * This function implements the reset driver op to deassert a device's reset
  * using the TI SCI protocol. This invokes the function ti_sci_reset_set()
  * with the corresponding parameters as passed in, but with the @assert
  * argument set to false for deasserting the reset.
  *
  * Return: 0 for successful request, else a corresponding error value
  */
 static int ti_sci_reset_deassert(struct reset_controller_dev *rcdev,
 				 unsigned long id)
 {
 	return ti_sci_reset_set(rcdev, id, false);
 }

 /**
  * ti_sci_reset_status() - check device reset status
  * @rcdev: reset controller entity
  * @id: ID of reset to be checked
  *
  * This function implements the reset driver op to return the status of a
  * device's reset using the TI SCI protocol. The reset register value is read
  * by invoking the TI SCI device operation .get_device_resets(), and the
  * status of the specific reset is extracted and returned using this reset's
  * reset mask.
  *
  * Return: 0 if reset is deasserted, or a non-zero value if reset is asserted
  */
 static int ti_sci_reset_status(struct reset_controller_dev *rcdev,
 			       unsigned long id)
 {
 	struct ti_sci_reset_data *data = to_ti_sci_reset_data(rcdev);
 	const struct ti_sci_handle *sci = data->sci;
 	const struct ti_sci_dev_ops *dev_ops = &sci->ops.dev_ops;
 	struct ti_sci_reset_control *control;
 	u32 reset_state;
 	int ret;

 	control = idr_find(&data->idr, id);
 	if (!control)
 		return -EINVAL;

 	ret = dev_ops->get_device_resets(sci, control->dev_id, &reset_state);
 	if (ret)
 		return ret;

 	return reset_state & control->reset_mask;
 }

 static const struct reset_control_ops ti_sci_reset_ops = {
 	.assert		= ti_sci_reset_assert,
 	.deassert	= ti_sci_reset_deassert,
 	.status		= ti_sci_reset_status,
 };

 /**
  * ti_sci_reset_of_xlate() - translate a set of OF arguments to a reset ID
  * @rcdev: reset controller entity
  * @reset_spec: OF reset argument specifier
  *
  * This function performs the translation of the reset argument specifier
  * values defined in a reset consumer device node. The function allocates a
  * reset control structure for that device reset, and will be used by the
  * driver for performing any reset functions on that reset. An idr structure
  * is allocated and used to map to the reset control structure. This idr
  * is used by the driver to do reset lookups.
  *
  * Return: 0 for successful request, else a corresponding error value
  */
 static int ti_sci_reset_of_xlate(struct reset_controller_dev *rcdev,
 				 const struct of_phandle_args *reset_spec)
 {
 	struct ti_sci_reset_data *data = to_ti_sci_reset_data(rcdev);
 	struct ti_sci_reset_control *control;

 	if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells))
 		return -EINVAL;

 	control = devm_kzalloc(data->dev, sizeof(*control), GFP_KERNEL);
 	if (!control)
 		return -ENOMEM;

 	control->dev_id = reset_spec->args[0];
 	control->reset_mask = reset_spec->args[1];
 	mutex_init(&control->lock);

 	return idr_alloc(&data->idr, control, 0, 0, GFP_KERNEL);
 }

 static const struct of_device_id ti_sci_reset_of_match[] = {
 	{ .compatible = "ti,sci-reset", },
 	{ /* sentinel */ },
 };
 MODULE_DEVICE_TABLE(of, ti_sci_reset_of_match);

 static int ti_sci_reset_probe(struct platform_device *pdev)
 {
 	struct ti_sci_reset_data *data;

 	if (!pdev->dev.of_node)
 		return -ENODEV;

 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;

 	data->sci = devm_ti_sci_get_handle(&pdev->dev);
 	if (IS_ERR(data->sci))
 		return PTR_ERR(data->sci);

 	data->rcdev.ops = &ti_sci_reset_ops;
 	data->rcdev.owner = THIS_MODULE;
 	data->rcdev.of_node = pdev->dev.of_node;
 	data->rcdev.of_reset_n_cells = 2;
 	data->rcdev.of_xlate = ti_sci_reset_of_xlate;
 	data->dev = &pdev->dev;
 	idr_init(&data->idr);

 	platform_set_drvdata(pdev, data);

 	return reset_controller_register(&data->rcdev);
 }

 static int ti_sci_reset_remove(struct platform_device *pdev)
 {
 	struct ti_sci_reset_data *data = platform_get_drvdata(pdev);

 	reset_controller_unregister(&data->rcdev);

 	idr_destroy(&data->idr);

 	return 0;
 }

 static struct platform_driver ti_sci_reset_driver = {
 	.probe = ti_sci_reset_probe,
 	.remove = ti_sci_reset_remove,
 	.driver = {
 		.name = "ti-sci-reset",
 		.of_match_table = ti_sci_reset_of_match,
 	},
 };
 module_platform_driver(ti_sci_reset_driver);

 MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
 MODULE_DESCRIPTION("TI System Control Interface (TI SCI) Reset driver");
 MODULE_LICENSE("GPL v2");
	/*
	* Texas Instrument's System Control Interface (TI-SCI) reset driver
	*
	* Copyright (C) 2015-2017 Texas Instruments Incorporated - https://www.ti.com/
	* Andrew F. Davis <afd@ti.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* This program is distributed "as is" WITHOUT ANY WARRANTY of any
	* kind, whether express or implied; without even the implied warranty
	* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*/

	#include <linux/idr.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/reset-controller.h>
	#include <linux/soc/ti/ti_sci_protocol.h>

	/**
	* struct ti_sci_reset_control - reset control structure
	* @dev_id: SoC-specific device identifier
	* @reset_mask: reset mask to use for toggling reset
	* @lock: synchronize reset_mask read-modify-writes
	*/
	struct ti_sci_reset_control {
	u32 dev_id;
	u32 reset_mask;
	struct mutex lock;
	};

	/**
	* struct ti_sci_reset_data - reset controller information structure
	* @rcdev: reset controller entity
	* @dev: reset controller device pointer
	* @sci: TI SCI handle used for communication with system controller
	* @idr: idr structure for mapping ids to reset control structures
	*/
	struct ti_sci_reset_data {
	struct reset_controller_dev rcdev;
	struct device *dev;
	const struct ti_sci_handle *sci;
	struct idr idr;
	};

	#define to_ti_sci_reset_data(p) \
	container_of((p), struct ti_sci_reset_data, rcdev)

	/**
	* ti_sci_reset_set() - program a device's reset
	* @rcdev: reset controller entity
	* @id: ID of the reset to toggle
	* @assert: boolean flag to indicate assert or deassert
	*
	* This is a common internal function used to assert or deassert a device's
	* reset using the TI SCI protocol. The device's reset is asserted if the
	* @assert argument is true, or deasserted if @assert argument is false.
	* The mechanism itself is a read-modify-write procedure, the current device
	* reset register is read using a TI SCI device operation, the new value is
	* set or un-set using the reset's mask, and the new reset value written by
	* using another TI SCI device operation.
	*
	* Return: 0 for successful request, else a corresponding error value
	*/
	static int ti_sci_reset_set(struct reset_controller_dev *rcdev,
	unsigned long id, bool assert)
	{
	struct ti_sci_reset_data *data = to_ti_sci_reset_data(rcdev);
	const struct ti_sci_handle *sci = data->sci;
	const struct ti_sci_dev_ops *dev_ops = &sci->ops.dev_ops;
	struct ti_sci_reset_control *control;
	u32 reset_state;
	int ret;

	control = idr_find(&data->idr, id);
	if (!control)
	return -EINVAL;

	mutex_lock(&control->lock);

	ret = dev_ops->get_device_resets(sci, control->dev_id, &reset_state);
	if (ret)
	goto out;

	if (assert)
	reset_state \|= control->reset_mask;
	else
	reset_state &= ~control->reset_mask;

	ret = dev_ops->set_device_resets(sci, control->dev_id, reset_state);
	out:
	mutex_unlock(&control->lock);

	return ret;
	}

	/**
	* ti_sci_reset_assert() - assert device reset
	* @rcdev: reset controller entity
	* @id: ID of the reset to be asserted
	*
	* This function implements the reset driver op to assert a device's reset
	* using the TI SCI protocol. This invokes the function ti_sci_reset_set()
	* with the corresponding parameters as passed in, but with the @assert
	* argument set to true for asserting the reset.
	*
	* Return: 0 for successful request, else a corresponding error value
	*/
	static int ti_sci_reset_assert(struct reset_controller_dev *rcdev,
	unsigned long id)
	{
	return ti_sci_reset_set(rcdev, id, true);
	}

	/**
	* ti_sci_reset_deassert() - deassert device reset
	* @rcdev: reset controller entity
	* @id: ID of the reset to be deasserted
	*
	* This function implements the reset driver op to deassert a device's reset
	* using the TI SCI protocol. This invokes the function ti_sci_reset_set()
	* with the corresponding parameters as passed in, but with the @assert
	* argument set to false for deasserting the reset.
	*
	* Return: 0 for successful request, else a corresponding error value
	*/
	static int ti_sci_reset_deassert(struct reset_controller_dev *rcdev,
	unsigned long id)
	{
	return ti_sci_reset_set(rcdev, id, false);
	}

	/**
	* ti_sci_reset_status() - check device reset status
	* @rcdev: reset controller entity
	* @id: ID of reset to be checked
	*
	* This function implements the reset driver op to return the status of a
	* device's reset using the TI SCI protocol. The reset register value is read
	* by invoking the TI SCI device operation .get_device_resets(), and the
	* status of the specific reset is extracted and returned using this reset's
	* reset mask.
	*
	* Return: 0 if reset is deasserted, or a non-zero value if reset is asserted
	*/
	static int ti_sci_reset_status(struct reset_controller_dev *rcdev,
	unsigned long id)
	{
	struct ti_sci_reset_data *data = to_ti_sci_reset_data(rcdev);
	const struct ti_sci_handle *sci = data->sci;
	const struct ti_sci_dev_ops *dev_ops = &sci->ops.dev_ops;
	struct ti_sci_reset_control *control;
	u32 reset_state;
	int ret;

	control = idr_find(&data->idr, id);
	if (!control)
	return -EINVAL;

	ret = dev_ops->get_device_resets(sci, control->dev_id, &reset_state);
	if (ret)
	return ret;

	return reset_state & control->reset_mask;
	}

	static const struct reset_control_ops ti_sci_reset_ops = {
	.assert = ti_sci_reset_assert,
	.deassert = ti_sci_reset_deassert,
	.status = ti_sci_reset_status,
	};

	/**
	* ti_sci_reset_of_xlate() - translate a set of OF arguments to a reset ID
	* @rcdev: reset controller entity
	* @reset_spec: OF reset argument specifier
	*
	* This function performs the translation of the reset argument specifier
	* values defined in a reset consumer device node. The function allocates a
	* reset control structure for that device reset, and will be used by the
	* driver for performing any reset functions on that reset. An idr structure
	* is allocated and used to map to the reset control structure. This idr
	* is used by the driver to do reset lookups.
	*
	* Return: 0 for successful request, else a corresponding error value
	*/
	static int ti_sci_reset_of_xlate(struct reset_controller_dev *rcdev,
	const struct of_phandle_args *reset_spec)
	{
	struct ti_sci_reset_data *data = to_ti_sci_reset_data(rcdev);
	struct ti_sci_reset_control *control;

	if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells))
	return -EINVAL;

	control = devm_kzalloc(data->dev, sizeof(*control), GFP_KERNEL);
	if (!control)
	return -ENOMEM;

	control->dev_id = reset_spec->args[0];
	control->reset_mask = reset_spec->args[1];
	mutex_init(&control->lock);

	return idr_alloc(&data->idr, control, 0, 0, GFP_KERNEL);
	}

	static const struct of_device_id ti_sci_reset_of_match[] = {
	{ .compatible = "ti,sci-reset", },
	{ /* sentinel */ },
	};
	MODULE_DEVICE_TABLE(of, ti_sci_reset_of_match);

	static int ti_sci_reset_probe(struct platform_device *pdev)
	{
	struct ti_sci_reset_data *data;

	if (!pdev->dev.of_node)
	return -ENODEV;

	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
	if (!data)
	return -ENOMEM;

	data->sci = devm_ti_sci_get_handle(&pdev->dev);
	if (IS_ERR(data->sci))
	return PTR_ERR(data->sci);

	data->rcdev.ops = &ti_sci_reset_ops;
	data->rcdev.owner = THIS_MODULE;
	data->rcdev.of_node = pdev->dev.of_node;
	data->rcdev.of_reset_n_cells = 2;
	data->rcdev.of_xlate = ti_sci_reset_of_xlate;
	data->dev = &pdev->dev;
	idr_init(&data->idr);

	platform_set_drvdata(pdev, data);

	return reset_controller_register(&data->rcdev);
	}

	static int ti_sci_reset_remove(struct platform_device *pdev)
	{
	struct ti_sci_reset_data *data = platform_get_drvdata(pdev);

	reset_controller_unregister(&data->rcdev);

	idr_destroy(&data->idr);

	return 0;
	}

	static struct platform_driver ti_sci_reset_driver = {
	.probe = ti_sci_reset_probe,
	.remove = ti_sci_reset_remove,
	.driver = {
	.name = "ti-sci-reset",
	.of_match_table = ti_sci_reset_of_match,
	},
	};
	module_platform_driver(ti_sci_reset_driver);

	MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
	MODULE_DESCRIPTION("TI System Control Interface (TI SCI) Reset driver");
	MODULE_LICENSE("GPL v2");