132 lines
3.3 KiB
C
132 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Reset driver for the StarFive JH71X0 SoCs
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*
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* Copyright (C) 2021 Emil Renner Berthing <kernel@esmil.dk>
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*/
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#include <linux/bitmap.h>
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#include <linux/device.h>
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#include <linux/io.h>
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#include <linux/iopoll.h>
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#include <linux/reset-controller.h>
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#include <linux/spinlock.h>
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#include "reset-starfive-jh71x0.h"
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struct jh71x0_reset {
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struct reset_controller_dev rcdev;
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/* protect registers against concurrent read-modify-write */
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spinlock_t lock;
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void __iomem *assert;
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void __iomem *status;
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const u32 *asserted;
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};
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static inline struct jh71x0_reset *
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jh71x0_reset_from(struct reset_controller_dev *rcdev)
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{
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return container_of(rcdev, struct jh71x0_reset, rcdev);
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}
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static int jh71x0_reset_update(struct reset_controller_dev *rcdev,
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unsigned long id, bool assert)
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{
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struct jh71x0_reset *data = jh71x0_reset_from(rcdev);
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unsigned long offset = id / 32;
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u32 mask = BIT(id % 32);
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void __iomem *reg_assert = data->assert + offset * sizeof(u32);
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void __iomem *reg_status = data->status + offset * sizeof(u32);
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u32 done = data->asserted ? data->asserted[offset] & mask : 0;
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u32 value;
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unsigned long flags;
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int ret;
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if (!assert)
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done ^= mask;
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spin_lock_irqsave(&data->lock, flags);
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value = readl(reg_assert);
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if (assert)
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value |= mask;
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else
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value &= ~mask;
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writel(value, reg_assert);
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/* if the associated clock is gated, deasserting might otherwise hang forever */
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ret = readl_poll_timeout_atomic(reg_status, value, (value & mask) == done, 0, 1000);
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spin_unlock_irqrestore(&data->lock, flags);
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return ret;
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}
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static int jh71x0_reset_assert(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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return jh71x0_reset_update(rcdev, id, true);
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}
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static int jh71x0_reset_deassert(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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return jh71x0_reset_update(rcdev, id, false);
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}
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static int jh71x0_reset_reset(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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int ret;
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ret = jh71x0_reset_assert(rcdev, id);
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if (ret)
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return ret;
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return jh71x0_reset_deassert(rcdev, id);
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}
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static int jh71x0_reset_status(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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struct jh71x0_reset *data = jh71x0_reset_from(rcdev);
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unsigned long offset = id / 32;
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u32 mask = BIT(id % 32);
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void __iomem *reg_status = data->status + offset * sizeof(u32);
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u32 value = readl(reg_status);
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return !((value ^ data->asserted[offset]) & mask);
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}
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static const struct reset_control_ops jh71x0_reset_ops = {
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.assert = jh71x0_reset_assert,
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.deassert = jh71x0_reset_deassert,
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.reset = jh71x0_reset_reset,
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.status = jh71x0_reset_status,
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};
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int reset_starfive_jh71x0_register(struct device *dev, struct device_node *of_node,
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void __iomem *assert, void __iomem *status,
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const u32 *asserted, unsigned int nr_resets,
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struct module *owner)
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{
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struct jh71x0_reset *data;
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data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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data->rcdev.ops = &jh71x0_reset_ops;
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data->rcdev.owner = owner;
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data->rcdev.nr_resets = nr_resets;
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data->rcdev.dev = dev;
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data->rcdev.of_node = of_node;
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spin_lock_init(&data->lock);
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data->assert = assert;
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data->status = status;
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data->asserted = asserted;
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return devm_reset_controller_register(dev, &data->rcdev);
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}
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EXPORT_SYMBOL_GPL(reset_starfive_jh71x0_register);
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