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// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/*
* SP7021 reset driver
*
* Copyright (C) Sunplus Technology Co., Ltd.
* All rights reserved.
*/
#include <linux/io.h>
#include <linux/init.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/reset-controller.h>
#include <linux/reboot.h>
/* HIWORD_MASK_REG BITS */
#define BITS_PER_HWM_REG 16
/* resets HW info: reg_index_shift */
static const u32 sp_resets[] = {
/* SP7021: mo_reset0 ~ mo_reset9 */
0x00,
0x02,
0x03,
0x04,
0x05,
0x06,
0x07,
0x08,
0x09,
0x0a,
0x0b,
0x0d,
0x0e,
0x0f,
0x10,
0x12,
0x14,
0x15,
0x16,
0x17,
0x18,
0x19,
0x1a,
0x1b,
0x1c,
0x1d,
0x1e,
0x1f,
0x20,
0x21,
0x22,
0x23,
0x24,
0x25,
0x26,
0x2a,
0x2b,
0x2d,
0x2e,
0x30,
0x31,
0x32,
0x33,
0x3d,
0x3e,
0x3f,
0x42,
0x44,
0x4b,
0x4c,
0x4d,
0x4e,
0x4f,
0x50,
0x55,
0x60,
0x61,
0x6a,
0x6f,
0x70,
0x73,
0x74,
0x86,
0x8a,
0x8b,
0x8d,
0x8e,
0x8f,
0x90,
0x92,
0x93,
0x94,
0x95,
0x96,
0x97,
0x98,
0x99,
};
struct sp_reset {
struct reset_controller_dev rcdev;
struct notifier_block notifier;
void __iomem *base;
};
static inline struct sp_reset *to_sp_reset(struct reset_controller_dev *rcdev)
{
return container_of(rcdev, struct sp_reset, rcdev);
}
static int sp_reset_update(struct reset_controller_dev *rcdev,
unsigned long id, bool assert)
{
struct sp_reset *reset = to_sp_reset(rcdev);
int index = sp_resets[id] / BITS_PER_HWM_REG;
int shift = sp_resets[id] % BITS_PER_HWM_REG;
u32 val;
val = (1 << (16 + shift)) | (assert << shift);
writel(val, reset->base + (index * 4));
return 0;
}
static int sp_reset_assert(struct reset_controller_dev *rcdev,
unsigned long id)
{
return sp_reset_update(rcdev, id, true);
}
static int sp_reset_deassert(struct reset_controller_dev *rcdev,
unsigned long id)
{
return sp_reset_update(rcdev, id, false);
}
static int sp_reset_status(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct sp_reset *reset = to_sp_reset(rcdev);
int index = sp_resets[id] / BITS_PER_HWM_REG;
int shift = sp_resets[id] % BITS_PER_HWM_REG;
u32 reg;
reg = readl(reset->base + (index * 4));
return !!(reg & BIT(shift));
}
static const struct reset_control_ops sp_reset_ops = {
.assert = sp_reset_assert,
.deassert = sp_reset_deassert,
.status = sp_reset_status,
};
static int sp_restart(struct notifier_block *nb, unsigned long mode,
void *cmd)
{
struct sp_reset *reset = container_of(nb, struct sp_reset, notifier);
sp_reset_assert(&reset->rcdev, 0);
sp_reset_deassert(&reset->rcdev, 0);
return NOTIFY_DONE;
}
static int sp_reset_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct sp_reset *reset;
struct resource *res;
int ret;
reset = devm_kzalloc(dev, sizeof(*reset), GFP_KERNEL);
if (!reset)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
reset->base = devm_ioremap_resource(dev, res);
if (IS_ERR(reset->base))
return PTR_ERR(reset->base);
reset->rcdev.ops = &sp_reset_ops;
reset->rcdev.owner = THIS_MODULE;
reset->rcdev.of_node = dev->of_node;
reset->rcdev.nr_resets = resource_size(res) / 4 * BITS_PER_HWM_REG;
ret = devm_reset_controller_register(dev, &reset->rcdev);
if (ret)
return ret;
reset->notifier.notifier_call = sp_restart;
reset->notifier.priority = 192;
return register_restart_handler(&reset->notifier);
}
static const struct of_device_id sp_reset_dt_ids[] = {
{.compatible = "sunplus,sp7021-reset",},
{ /* sentinel */ },
};
static struct platform_driver sp_reset_driver = {
.probe = sp_reset_probe,
.driver = {
.name = "sunplus-reset",
.of_match_table = sp_reset_dt_ids,
.suppress_bind_attrs = true,
},
};
builtin_platform_driver(sp_reset_driver);
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