diff options
Diffstat (limited to 'drivers/reset')
| -rw-r--r-- | drivers/reset/Kconfig | 8 | ||||
| -rw-r--r-- | drivers/reset/Makefile | 1 | ||||
| -rw-r--r-- | drivers/reset/reset-ti-sci.c | 269 |
3 files changed, 278 insertions, 0 deletions
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig index 61fabf6ddaec..608c071e4bbf 100644 --- a/drivers/reset/Kconfig +++ b/drivers/reset/Kconfig @@ -87,6 +87,14 @@ config RESET_SUNXI help This enables the reset driver for Allwinner SoCs. +config RESET_TI_SCI + tristate "TI System Control Interface (TI-SCI) reset driver" + depends on TI_SCI_PROTOCOL + help + This enables the reset driver support over TI System Control Interface + available on some new TI's SoCs. If you wish to use reset resources + managed by the TI System Controller, say Y here. Otherwise, say N. + config RESET_TI_SYSCON tristate "TI SYSCON Reset Driver" depends on HAS_IOMEM diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile index e422a04f7b85..7081f9da2599 100644 --- a/drivers/reset/Makefile +++ b/drivers/reset/Makefile @@ -14,6 +14,7 @@ obj-$(CONFIG_RESET_PISTACHIO) += reset-pistachio.o obj-$(CONFIG_RESET_SOCFPGA) += reset-socfpga.o obj-$(CONFIG_RESET_STM32) += reset-stm32.o obj-$(CONFIG_RESET_SUNXI) += reset-sunxi.o +obj-$(CONFIG_RESET_TI_SCI) += reset-ti-sci.o obj-$(CONFIG_RESET_TI_SYSCON) += reset-ti-syscon.o obj-$(CONFIG_RESET_UNIPHIER) += reset-uniphier.o obj-$(CONFIG_RESET_ZX2967) += reset-zx2967.o diff --git a/drivers/reset/reset-ti-sci.c b/drivers/reset/reset-ti-sci.c new file mode 100644 index 000000000000..bf68729ab729 --- /dev/null +++ b/drivers/reset/reset-ti-sci.c @@ -0,0 +1,269 @@ +/* + * 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"); |