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https://github.com/brain-hackers/u-boot-brain
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207 lines
5.7 KiB
C
207 lines
5.7 KiB
C
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// SPDX-License-Identifier: GPL-2.0+
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/*
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* Texas Instruments System Control Interface (TI SCI) reset driver
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*
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* Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
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* Andreas Dannenberg <dannenberg@ti.com>
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*
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* Loosely based on Linux kernel reset-ti-sci.c...
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*/
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#include <common.h>
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#include <dm.h>
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#include <errno.h>
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#include <reset-uclass.h>
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#include <linux/soc/ti/ti_sci_protocol.h>
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/**
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* struct ti_sci_reset_data - reset controller information structure
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* @sci: TI SCI handle used for communication with system controller
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*/
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struct ti_sci_reset_data {
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const struct ti_sci_handle *sci;
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};
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static int ti_sci_reset_probe(struct udevice *dev)
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{
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struct ti_sci_reset_data *data = dev_get_priv(dev);
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debug("%s(dev=%p)\n", __func__, dev);
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if (!data)
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return -ENOMEM;
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/* Store handle for communication with the system controller */
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data->sci = ti_sci_get_handle(dev);
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if (IS_ERR(data->sci))
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return PTR_ERR(data->sci);
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return 0;
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}
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static int ti_sci_reset_of_xlate(struct reset_ctl *rst,
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struct ofnode_phandle_args *args)
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{
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debug("%s(rst=%p, args_count=%d)\n", __func__, rst, args->args_count);
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if (args->args_count != 2) {
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debug("Invalid args_count: %d\n", args->args_count);
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return -EINVAL;
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}
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/*
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* On TI SCI-based devices, the reset provider id field is used as a
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* device ID, and the data field is used as the associated reset mask.
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*/
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rst->id = args->args[0];
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rst->data = args->args[1];
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return 0;
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}
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static int ti_sci_reset_request(struct reset_ctl *rst)
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{
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debug("%s(rst=%p)\n", __func__, rst);
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return 0;
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}
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static int ti_sci_reset_free(struct reset_ctl *rst)
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{
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debug("%s(rst=%p)\n", __func__, rst);
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return 0;
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}
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/**
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* ti_sci_reset_set() - program a device's reset
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* @rst: Handle to a single reset signal
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* @assert: boolean flag to indicate assert or deassert
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*
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* This is a common internal function used to assert or deassert a device's
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* reset using the TI SCI protocol. The device's reset is asserted if the
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* @assert argument is true, or deasserted if @assert argument is false.
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* The mechanism itself is a read-modify-write procedure, the current device
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* reset register is read using a TI SCI device operation, the new value is
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* set or un-set using the reset's mask, and the new reset value written by
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* using another TI SCI device operation.
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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 ti_sci_reset_set(struct reset_ctl *rst, bool assert)
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{
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struct ti_sci_reset_data *data = dev_get_priv(rst->dev);
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const struct ti_sci_handle *sci = data->sci;
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const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops;
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u32 reset_state;
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int ret;
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ret = dops->get_device_resets(sci, rst->id, &reset_state);
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if (ret) {
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dev_err(rst->dev, "%s: get_device_resets failed (%d)\n",
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__func__, ret);
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return ret;
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}
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if (assert)
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reset_state |= rst->data;
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else
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reset_state &= ~rst->data;
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ret = dops->set_device_resets(sci, rst->id, reset_state);
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if (ret) {
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dev_err(rst->dev, "%s: set_device_resets failed (%d)\n",
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__func__, ret);
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return ret;
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}
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return 0;
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}
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/**
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* ti_sci_reset_assert() - assert device reset
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* @rst: Handle to a single reset signal
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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 TI SCI protocol. This invokes the function ti_sci_reset_set()
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* with the corresponding parameters as passed in, but with the @assert
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* argument set to true for asserting the reset.
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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 ti_sci_reset_assert(struct reset_ctl *rst)
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{
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debug("%s(rst=%p)\n", __func__, rst);
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return ti_sci_reset_set(rst, true);
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}
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/**
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* ti_sci_reset_deassert() - deassert device reset
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* @rst: Handle to a single reset signal
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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 TI SCI protocol. This invokes the function ti_sci_reset_set()
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* with the corresponding parameters as passed in, but with the @assert
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* argument set to false for deasserting the reset.
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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 ti_sci_reset_deassert(struct reset_ctl *rst)
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{
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debug("%s(rst=%p)\n", __func__, rst);
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return ti_sci_reset_set(rst, false);
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}
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/**
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* ti_sci_reset_status() - check device reset status
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* @rst: Handle to a single reset signal
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*
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* This function implements the reset driver op to return the status of a
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* device's reset using the TI SCI protocol. The reset register value is read
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* by invoking the TI SCI device operation .get_device_resets(), and the
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* status of the specific reset is extracted and returned using this reset's
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* reset mask.
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*
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* Return: 0 if reset is deasserted, or a non-zero value if reset is asserted
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*/
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static int ti_sci_reset_status(struct reset_ctl *rst)
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{
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struct ti_sci_reset_data *data = dev_get_priv(rst->dev);
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const struct ti_sci_handle *sci = data->sci;
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const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops;
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u32 reset_state;
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int ret;
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debug("%s(rst=%p)\n", __func__, rst);
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ret = dops->get_device_resets(sci, rst->id, &reset_state);
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if (ret) {
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dev_err(rst->dev, "%s: get_device_resets failed (%d)\n",
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__func__, ret);
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return ret;
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}
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return reset_state & rst->data;
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}
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static const struct udevice_id ti_sci_reset_of_match[] = {
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{ .compatible = "ti,sci-reset", },
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{ /* sentinel */ },
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};
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static struct reset_ops ti_sci_reset_ops = {
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.of_xlate = ti_sci_reset_of_xlate,
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.request = ti_sci_reset_request,
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.free = ti_sci_reset_free,
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.rst_assert = ti_sci_reset_assert,
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.rst_deassert = ti_sci_reset_deassert,
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.rst_status = ti_sci_reset_status,
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};
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U_BOOT_DRIVER(ti_sci_reset) = {
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.name = "ti-sci-reset",
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.id = UCLASS_RESET,
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.of_match = ti_sci_reset_of_match,
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.probe = ti_sci_reset_probe,
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.priv_auto_alloc_size = sizeof(struct ti_sci_reset_data),
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.ops = &ti_sci_reset_ops,
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};
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