reset.c
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/*
* Hisilicon Reset Controller Driver
*
* Copyright (c) 2015-2016 HiSilicon Technologies Co., Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/reset-controller.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include "reset.h"
#define HISI_RESET_BIT_MASK 0x1f
#define HISI_RESET_OFFSET_SHIFT 8
#define HISI_RESET_OFFSET_MASK 0xffff00
struct hisi_reset_controller {
spinlock_t lock;
void __iomem *membase;
struct reset_controller_dev rcdev;
};
#define to_hisi_reset_controller(rcdev) \
container_of(rcdev, struct hisi_reset_controller, rcdev)
static int hisi_reset_of_xlate(struct reset_controller_dev *rcdev,
const struct of_phandle_args *reset_spec)
{
u32 offset;
u8 bit;
offset = (reset_spec->args[0] << HISI_RESET_OFFSET_SHIFT)
& HISI_RESET_OFFSET_MASK;
bit = reset_spec->args[1] & HISI_RESET_BIT_MASK;
return (offset | bit);
}
static int hisi_reset_assert(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct hisi_reset_controller *rstc = to_hisi_reset_controller(rcdev);
unsigned long flags;
u32 offset, reg;
u8 bit;
offset = (id & HISI_RESET_OFFSET_MASK) >> HISI_RESET_OFFSET_SHIFT;
bit = id & HISI_RESET_BIT_MASK;
spin_lock_irqsave(&rstc->lock, flags);
reg = readl(rstc->membase + offset);
writel(reg | BIT(bit), rstc->membase + offset);
spin_unlock_irqrestore(&rstc->lock, flags);
return 0;
}
static int hisi_reset_deassert(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct hisi_reset_controller *rstc = to_hisi_reset_controller(rcdev);
unsigned long flags;
u32 offset, reg;
u8 bit;
offset = (id & HISI_RESET_OFFSET_MASK) >> HISI_RESET_OFFSET_SHIFT;
bit = id & HISI_RESET_BIT_MASK;
spin_lock_irqsave(&rstc->lock, flags);
reg = readl(rstc->membase + offset);
writel(reg & ~BIT(bit), rstc->membase + offset);
spin_unlock_irqrestore(&rstc->lock, flags);
return 0;
}
static const struct reset_control_ops hisi_reset_ops = {
.assert = hisi_reset_assert,
.deassert = hisi_reset_deassert,
};
struct hisi_reset_controller *hisi_reset_init(struct platform_device *pdev)
{
struct hisi_reset_controller *rstc;
struct resource *res;
rstc = devm_kmalloc(&pdev->dev, sizeof(*rstc), GFP_KERNEL);
if (!rstc)
return NULL;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
rstc->membase = devm_ioremap(&pdev->dev,
res->start, resource_size(res));
if (!rstc->membase)
return NULL;
spin_lock_init(&rstc->lock);
rstc->rcdev.owner = THIS_MODULE;
rstc->rcdev.ops = &hisi_reset_ops;
rstc->rcdev.of_node = pdev->dev.of_node;
rstc->rcdev.of_reset_n_cells = 2;
rstc->rcdev.of_xlate = hisi_reset_of_xlate;
reset_controller_register(&rstc->rcdev);
return rstc;
}
EXPORT_SYMBOL_GPL(hisi_reset_init);
void hisi_reset_exit(struct hisi_reset_controller *rstc)
{
reset_controller_unregister(&rstc->rcdev);
}
EXPORT_SYMBOL_GPL(hisi_reset_exit);