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/*
* Allwinner SoCs Reset Controller driver
*
* Copyright 2013 Maxime Ripard
*
* Maxime Ripard <maxime.ripard@free-electrons.com>
*
* 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.
*/
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.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 <linux/types.h>
struct sunxi_reset_data {
spinlock_t lock;
void __iomem *membase;
struct reset_controller_dev rcdev;
};
static int sunxi_reset_assert(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct sunxi_reset_data *data = container_of(rcdev,
struct sunxi_reset_data,
rcdev);
int bank = id / BITS_PER_LONG;
int offset = id % BITS_PER_LONG;
unsigned long flags;
u32 reg;
spin_lock_irqsave(&data->lock, flags);
reg = readl(data->membase + (bank * 4));
writel(reg & ~BIT(offset), data->membase + (bank * 4));
spin_unlock_irqrestore(&data->lock, flags);
return 0;
}
static int sunxi_reset_deassert(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct sunxi_reset_data *data = container_of(rcdev,
struct sunxi_reset_data,
rcdev);
int bank = id / BITS_PER_LONG;
int offset = id % BITS_PER_LONG;
unsigned long flags;
u32 reg;
spin_lock_irqsave(&data->lock, flags);
reg = readl(data->membase + (bank * 4));
writel(reg | BIT(offset), data->membase + (bank * 4));
spin_unlock_irqrestore(&data->lock, flags);
return 0;
}
static struct reset_control_ops sunxi_reset_ops = {
.assert = sunxi_reset_assert,
.deassert = sunxi_reset_deassert,
};
static int sunxi_reset_init(struct device_node *np)
{
struct sunxi_reset_data *data;
struct resource res;
resource_size_t size;
int ret;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
ret = of_address_to_resource(np, 0, &res);
if (ret)
goto err_alloc;
size = resource_size(&res);
if (!request_mem_region(res.start, size, np->name)) {
ret = -EBUSY;
goto err_alloc;
}
data->membase = ioremap(res.start, size);
if (!data->membase) {
ret = -ENOMEM;
goto err_alloc;
}
data->rcdev.owner = THIS_MODULE;
data->rcdev.nr_resets = size * 32;
data->rcdev.ops = &sunxi_reset_ops;
data->rcdev.of_node = np;
reset_controller_register(&data->rcdev);
return 0;
err_alloc:
kfree(data);
return ret;
};
/*
* These are the reset controller we need to initialize early on in
* our system, before we can even think of using a regular device
* driver for it.
*/
static const struct of_device_id sunxi_early_reset_dt_ids[] __initdata = {
{ .compatible = "allwinner,sun6i-a31-ahb1-reset", },
{ /* sentinel */ },
};
void __init sun6i_reset_init(void)
{
struct device_node *np;
for_each_matching_node(np, sunxi_early_reset_dt_ids)
sunxi_reset_init(np);
}
/*
* And these are the controllers we can register through the regular
* device model.
*/
static const struct of_device_id sunxi_reset_dt_ids[] = {
{ .compatible = "allwinner,sun6i-a31-clock-reset", },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, sunxi_reset_dt_ids);
static int sunxi_reset_probe(struct platform_device *pdev)
{
return sunxi_reset_init(pdev->dev.of_node);
}
static int sunxi_reset_remove(struct platform_device *pdev)
{
struct sunxi_reset_data *data = platform_get_drvdata(pdev);
reset_controller_unregister(&data->rcdev);
iounmap(data->membase);
kfree(data);
return 0;
}
static struct platform_driver sunxi_reset_driver = {
.probe = sunxi_reset_probe,
.remove = sunxi_reset_remove,
.driver = {
.name = "sunxi-reset",
.owner = THIS_MODULE,
.of_match_table = sunxi_reset_dt_ids,
},
};
module_platform_driver(sunxi_reset_driver);
MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
MODULE_DESCRIPTION("Allwinner SoCs Reset Controller Driver");
MODULE_LICENSE("GPL");
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