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// SPDX-License-Identifier: GPL-2.0+
/*
* Texas Instruments System Control Interface (TI SCI) reset driver
*
* Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
* Andreas Dannenberg <dannenberg@ti.com>
*
* Loosely based on Linux kernel reset-ti-sci.c...
*/
#include <common.h>
#include <dm.h>
#include <errno.h>
#include <reset-uclass.h>
#include <linux/soc/ti/ti_sci_protocol.h>
/**
* struct ti_sci_reset_data - reset controller information structure
* @sci: TI SCI handle used for communication with system controller
*/
struct ti_sci_reset_data {
const struct ti_sci_handle *sci;
};
static int ti_sci_reset_probe(struct udevice *dev)
{
struct ti_sci_reset_data *data = dev_get_priv(dev);
debug("%s(dev=%p)\n", __func__, dev);
if (!data)
return -ENOMEM;
/* Store handle for communication with the system controller */
data->sci = ti_sci_get_handle(dev);
if (IS_ERR(data->sci))
return PTR_ERR(data->sci);
return 0;
}
static int ti_sci_reset_of_xlate(struct reset_ctl *rst,
struct ofnode_phandle_args *args)
{
debug("%s(rst=%p, args_count=%d)\n", __func__, rst, args->args_count);
if (args->args_count != 2) {
debug("Invalid args_count: %d\n", args->args_count);
return -EINVAL;
}
/*
* On TI SCI-based devices, the reset provider id field is used as a
* device ID, and the data field is used as the associated reset mask.
*/
rst->id = args->args[0];
rst->data = args->args[1];
return 0;
}
static int ti_sci_reset_request(struct reset_ctl *rst)
{
debug("%s(rst=%p)\n", __func__, rst);
return 0;
}
static int ti_sci_reset_free(struct reset_ctl *rst)
{
debug("%s(rst=%p)\n", __func__, rst);
return 0;
}
/**
* ti_sci_reset_set() - program a device's reset
* @rst: Handle to a single reset signal
* @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_ctl *rst, bool assert)
{
struct ti_sci_reset_data *data = dev_get_priv(rst->dev);
const struct ti_sci_handle *sci = data->sci;
const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops;
u32 reset_state;
int ret;
ret = dops->get_device_resets(sci, rst->id, &reset_state);
if (ret) {
dev_err(rst->dev, "%s: get_device_resets failed (%d)\n",
__func__, ret);
return ret;
}
if (assert)
reset_state |= rst->data;
else
reset_state &= ~rst->data;
ret = dops->set_device_resets(sci, rst->id, reset_state);
if (ret) {
dev_err(rst->dev, "%s: set_device_resets failed (%d)\n",
__func__, ret);
return ret;
}
return 0;
}
/**
* ti_sci_reset_assert() - assert device reset
* @rst: Handle to a single reset signal
*
* 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_ctl *rst)
{
debug("%s(rst=%p)\n", __func__, rst);
return ti_sci_reset_set(rst, true);
}
/**
* ti_sci_reset_deassert() - deassert device reset
* @rst: Handle to a single reset signal
*
* 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_ctl *rst)
{
debug("%s(rst=%p)\n", __func__, rst);
return ti_sci_reset_set(rst, false);
}
/**
* ti_sci_reset_status() - check device reset status
* @rst: Handle to a single reset signal
*
* 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_ctl *rst)
{
struct ti_sci_reset_data *data = dev_get_priv(rst->dev);
const struct ti_sci_handle *sci = data->sci;
const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops;
u32 reset_state;
int ret;
debug("%s(rst=%p)\n", __func__, rst);
ret = dops->get_device_resets(sci, rst->id, &reset_state);
if (ret) {
dev_err(rst->dev, "%s: get_device_resets failed (%d)\n",
__func__, ret);
return ret;
}
return reset_state & rst->data;
}
static const struct udevice_id ti_sci_reset_of_match[] = {
{ .compatible = "ti,sci-reset", },
{ /* sentinel */ },
};
static struct reset_ops ti_sci_reset_ops = {
.of_xlate = ti_sci_reset_of_xlate,
.request = ti_sci_reset_request,
.free = ti_sci_reset_free,
.rst_assert = ti_sci_reset_assert,
.rst_deassert = ti_sci_reset_deassert,
.rst_status = ti_sci_reset_status,
};
U_BOOT_DRIVER(ti_sci_reset) = {
.name = "ti-sci-reset",
.id = UCLASS_RESET,
.of_match = ti_sci_reset_of_match,
.probe = ti_sci_reset_probe,
.priv_auto_alloc_size = sizeof(struct ti_sci_reset_data),
.ops = &ti_sci_reset_ops,
};
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