/* * Texas Instrument's System Control Interface (TI-SCI) reset driver * * Copyright (C) 2015-2017 Texas Instruments Incorporated - http://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");