reset: Add Allwinner SoCs Reset Controller Driver

obj-$(CONFIG_RESET_CONTROLLER) += core.o

obj-$(CONFIG_ARCH_SUNXI) += reset-sunxi.o

/*

 * 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");