Something went wrong. Try again.
Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Something went wrong. Try again.
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260// SPDX-License-Identifier: GPL-2.0-only/* * 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> */
#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 void 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);}
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");