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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2019 Intel Corporation.
* Lei Chuanhua <Chuanhua.lei@intel.com>
*/
#include <linux/bitfield.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/regmap.h>
#include <linux/reset-controller.h>
#define RCU_RST_STAT 0x0024
#define RCU_RST_REQ 0x0048
#define REG_OFFSET_MASK GENMASK(31, 16)
#define BIT_OFFSET_MASK GENMASK(15, 8)
#define STAT_BIT_OFFSET_MASK GENMASK(7, 0)
#define to_reset_data(x) container_of(x, struct intel_reset_data, rcdev)
struct intel_reset_soc {
bool legacy;
u32 reset_cell_count;
};
struct intel_reset_data {
struct reset_controller_dev rcdev;
struct notifier_block restart_nb;
const struct intel_reset_soc *soc_data;
struct regmap *regmap;
struct device *dev;
u32 reboot_id;
};
static const struct regmap_config intel_rcu_regmap_config = {
.name = "intel-reset",
.reg_bits = 32,
.reg_stride = 4,
.val_bits = 32,
.fast_io = true,
};
/*
* Reset status register offset relative to
* the reset control register(X) is X + 4
*/
static u32 id_to_reg_and_bit_offsets(struct intel_reset_data *data,
unsigned long id, u32 *rst_req,
u32 *req_bit, u32 *stat_bit)
{
*rst_req = FIELD_GET(REG_OFFSET_MASK, id);
*req_bit = FIELD_GET(BIT_OFFSET_MASK, id);
if (data->soc_data->legacy)
*stat_bit = FIELD_GET(STAT_BIT_OFFSET_MASK, id);
else
*stat_bit = *req_bit;
if (data->soc_data->legacy && *rst_req == RCU_RST_REQ)
return RCU_RST_STAT;
else
return *rst_req + 0x4;
}
static int intel_set_clr_bits(struct intel_reset_data *data, unsigned long id,
bool set)
{
u32 rst_req, req_bit, rst_stat, stat_bit, val;
int ret;
rst_stat = id_to_reg_and_bit_offsets(data, id, &rst_req,
&req_bit, &stat_bit);
val = set ? BIT(req_bit) : 0;
ret = regmap_update_bits(data->regmap, rst_req, BIT(req_bit), val);
if (ret)
return ret;
return regmap_read_poll_timeout(data->regmap, rst_stat, val,
set == !!(val & BIT(stat_bit)), 20,
200);
}
static int intel_assert_device(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct intel_reset_data *data = to_reset_data(rcdev);
int ret;
ret = intel_set_clr_bits(data, id, true);
if (ret)
dev_err(data->dev, "Reset assert failed %d\n", ret);
return ret;
}
static int intel_deassert_device(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct intel_reset_data *data = to_reset_data(rcdev);
int ret;
ret = intel_set_clr_bits(data, id, false);
if (ret)
dev_err(data->dev, "Reset deassert failed %d\n", ret);
return ret;
}
static int intel_reset_status(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct intel_reset_data *data = to_reset_data(rcdev);
u32 rst_req, req_bit, rst_stat, stat_bit, val;
int ret;
rst_stat = id_to_reg_and_bit_offsets(data, id, &rst_req,
&req_bit, &stat_bit);
ret = regmap_read(data->regmap, rst_stat, &val);
if (ret)
return ret;
return !!(val & BIT(stat_bit));
}
static const struct reset_control_ops intel_reset_ops = {
.assert = intel_assert_device,
.deassert = intel_deassert_device,
.status = intel_reset_status,
};
static int intel_reset_xlate(struct reset_controller_dev *rcdev,
const struct of_phandle_args *spec)
{
struct intel_reset_data *data = to_reset_data(rcdev);
u32 id;
if (spec->args[1] > 31)
return -EINVAL;
id = FIELD_PREP(REG_OFFSET_MASK, spec->args[0]);
id |= FIELD_PREP(BIT_OFFSET_MASK, spec->args[1]);
if (data->soc_data->legacy) {
if (spec->args[2] > 31)
return -EINVAL;
id |= FIELD_PREP(STAT_BIT_OFFSET_MASK, spec->args[2]);
}
return id;
}
static int intel_reset_restart_handler(struct notifier_block *nb,
unsigned long action, void *data)
{
struct intel_reset_data *reset_data;
reset_data = container_of(nb, struct intel_reset_data, restart_nb);
intel_assert_device(&reset_data->rcdev, reset_data->reboot_id);
return NOTIFY_DONE;
}
static int intel_reset_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct device *dev = &pdev->dev;
struct intel_reset_data *data;
void __iomem *base;
u32 rb_id[3];
int ret;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->soc_data = of_device_get_match_data(dev);
if (!data->soc_data)
return -ENODEV;
base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(base))
return PTR_ERR(base);
data->regmap = devm_regmap_init_mmio(dev, base,
&intel_rcu_regmap_config);
if (IS_ERR(data->regmap)) {
dev_err(dev, "regmap initialization failed\n");
return PTR_ERR(data->regmap);
}
ret = device_property_read_u32_array(dev, "intel,global-reset", rb_id,
data->soc_data->reset_cell_count);
if (ret) {
dev_err(dev, "Failed to get global reset offset!\n");
return ret;
}
data->dev = dev;
data->rcdev.of_node = np;
data->rcdev.owner = dev->driver->owner;
data->rcdev.ops = &intel_reset_ops;
data->rcdev.of_xlate = intel_reset_xlate;
data->rcdev.of_reset_n_cells = data->soc_data->reset_cell_count;
ret = devm_reset_controller_register(&pdev->dev, &data->rcdev);
if (ret)
return ret;
data->reboot_id = FIELD_PREP(REG_OFFSET_MASK, rb_id[0]);
data->reboot_id |= FIELD_PREP(BIT_OFFSET_MASK, rb_id[1]);
if (data->soc_data->legacy)
data->reboot_id |= FIELD_PREP(STAT_BIT_OFFSET_MASK, rb_id[2]);
data->restart_nb.notifier_call = intel_reset_restart_handler;
data->restart_nb.priority = 128;
register_restart_handler(&data->restart_nb);
return 0;
}
static const struct intel_reset_soc xrx200_data = {
.legacy = true,
.reset_cell_count = 3,
};
static const struct intel_reset_soc lgm_data = {
.legacy = false,
.reset_cell_count = 2,
};
static const struct of_device_id intel_reset_match[] = {
{ .compatible = "intel,rcu-lgm", .data = &lgm_data },
{ .compatible = "intel,rcu-xrx200", .data = &xrx200_data },
{}
};
static struct platform_driver intel_reset_driver = {
.probe = intel_reset_probe,
.driver = {
.name = "intel-reset",
.of_match_table = intel_reset_match,
},
};
static int __init intel_reset_init(void)
{
return platform_driver_register(&intel_reset_driver);
}
/*
* RCU is system core entity which is in Always On Domain whose clocks
* or resource initialization happens in system core initialization.
* Also, it is required for most of the platform or architecture
* specific devices to perform reset operation as part of initialization.
* So perform RCU as post core initialization.
*/
postcore_initcall(intel_reset_init);
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