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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Reset driver for the StarFive JH7100 SoC
*
* Copyright (C) 2021 Emil Renner Berthing <kernel@esmil.dk>
*/
#include <linux/bitmap.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/iopoll.h>
#include <linux/reset-controller.h>
#include <linux/spinlock.h>
#include "reset-starfive-jh71x0.h"
struct jh7100_reset {
struct reset_controller_dev rcdev;
/* protect registers against concurrent read-modify-write */
spinlock_t lock;
void __iomem *assert;
void __iomem *status;
const u64 *asserted;
};
static inline struct jh7100_reset *
jh7100_reset_from(struct reset_controller_dev *rcdev)
{
return container_of(rcdev, struct jh7100_reset, rcdev);
}
static int jh7100_reset_update(struct reset_controller_dev *rcdev,
unsigned long id, bool assert)
{
struct jh7100_reset *data = jh7100_reset_from(rcdev);
unsigned long offset = BIT_ULL_WORD(id);
u64 mask = BIT_ULL_MASK(id);
void __iomem *reg_assert = data->assert + offset * sizeof(u64);
void __iomem *reg_status = data->status + offset * sizeof(u64);
u64 done = data->asserted ? data->asserted[offset] & mask : 0;
u64 value;
unsigned long flags;
int ret;
if (!assert)
done ^= mask;
spin_lock_irqsave(&data->lock, flags);
value = readq(reg_assert);
if (assert)
value |= mask;
else
value &= ~mask;
writeq(value, reg_assert);
/* if the associated clock is gated, deasserting might otherwise hang forever */
ret = readq_poll_timeout_atomic(reg_status, value, (value & mask) == done, 0, 1000);
spin_unlock_irqrestore(&data->lock, flags);
return ret;
}
static int jh7100_reset_assert(struct reset_controller_dev *rcdev,
unsigned long id)
{
return jh7100_reset_update(rcdev, id, true);
}
static int jh7100_reset_deassert(struct reset_controller_dev *rcdev,
unsigned long id)
{
return jh7100_reset_update(rcdev, id, false);
}
static int jh7100_reset_reset(struct reset_controller_dev *rcdev,
unsigned long id)
{
int ret;
ret = jh7100_reset_assert(rcdev, id);
if (ret)
return ret;
return jh7100_reset_deassert(rcdev, id);
}
static int jh7100_reset_status(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct jh7100_reset *data = jh7100_reset_from(rcdev);
unsigned long offset = BIT_ULL_WORD(id);
u64 mask = BIT_ULL_MASK(id);
void __iomem *reg_status = data->status + offset * sizeof(u64);
u64 value = readq(reg_status);
return !((value ^ data->asserted[offset]) & mask);
}
static const struct reset_control_ops jh7100_reset_ops = {
.assert = jh7100_reset_assert,
.deassert = jh7100_reset_deassert,
.reset = jh7100_reset_reset,
.status = jh7100_reset_status,
};
int reset_starfive_jh7100_register(struct device *dev, struct device_node *of_node,
void __iomem *assert, void __iomem *status,
const u64 *asserted, unsigned int nr_resets,
struct module *owner)
{
struct jh7100_reset *data;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->rcdev.ops = &jh7100_reset_ops;
data->rcdev.owner = owner;
data->rcdev.nr_resets = nr_resets;
data->rcdev.dev = dev;
data->rcdev.of_node = of_node;
spin_lock_init(&data->lock);
data->assert = assert;
data->status = status;
data->asserted = asserted;
return devm_reset_controller_register(dev, &data->rcdev);
}
EXPORT_SYMBOL_GPL(reset_starfive_jh7100_register);
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