1/*
  2 * Allwinner SoCs Reset Controller driver
  3 *
  4 * Copyright 2013 Maxime Ripard
  5 *
  6 * Maxime Ripard <maxime.ripard@free-electrons.com>
  7 *
  8 * This program is free software; you can redistribute it and/or modify
  9 * it under the terms of the GNU General Public License as published by
 10 * the Free Software Foundation; either version 2 of the License, or
 11 * (at your option) any later version.
 12 */
 13
 14#include <linux/err.h>
 15#include <linux/io.h>
 16#include <linux/module.h>
 17#include <linux/of.h>
 18#include <linux/of_address.h>
 19#include <linux/platform_device.h>
 20#include <linux/reset-controller.h>
 21#include <linux/slab.h>
 22#include <linux/spinlock.h>
 23#include <linux/types.h>
 24
 25struct sunxi_reset_data {
 26	spinlock_t			lock;
 27	void __iomem			*membase;
 28	struct reset_controller_dev	rcdev;
 29};
 30
 31static int sunxi_reset_assert(struct reset_controller_dev *rcdev,
 32			      unsigned long id)
 33{
 34	struct sunxi_reset_data *data = container_of(rcdev,
 35						     struct sunxi_reset_data,
 36						     rcdev);
 37	int bank = id / BITS_PER_LONG;
 38	int offset = id % BITS_PER_LONG;
 39	unsigned long flags;
 40	u32 reg;
 41
 42	spin_lock_irqsave(&data->lock, flags);
 43
 44	reg = readl(data->membase + (bank * 4));
 45	writel(reg & ~BIT(offset), data->membase + (bank * 4));
 46
 47	spin_unlock_irqrestore(&data->lock, flags);
 48
 49	return 0;
 50}
 51
 52static int sunxi_reset_deassert(struct reset_controller_dev *rcdev,
 53				unsigned long id)
 54{
 55	struct sunxi_reset_data *data = container_of(rcdev,
 56						     struct sunxi_reset_data,
 57						     rcdev);
 58	int bank = id / BITS_PER_LONG;
 59	int offset = id % BITS_PER_LONG;
 60	unsigned long flags;
 61	u32 reg;
 62
 63	spin_lock_irqsave(&data->lock, flags);
 64
 65	reg = readl(data->membase + (bank * 4));
 66	writel(reg | BIT(offset), data->membase + (bank * 4));
 67
 68	spin_unlock_irqrestore(&data->lock, flags);
 69
 70	return 0;
 71}
 72
 73static const struct reset_control_ops sunxi_reset_ops = {
 74	.assert		= sunxi_reset_assert,
 75	.deassert	= sunxi_reset_deassert,
 76};
 77
 78static int sunxi_reset_init(struct device_node *np)
 79{
 80	struct sunxi_reset_data *data;
 81	struct resource res;
 82	resource_size_t size;
 83	int ret;
 84
 85	data = kzalloc(sizeof(*data), GFP_KERNEL);
 86	if (!data)
 87		return -ENOMEM;
 88
 89	ret = of_address_to_resource(np, 0, &res);
 90	if (ret)
 91		goto err_alloc;
 92
 93	size = resource_size(&res);
 94	if (!request_mem_region(res.start, size, np->name)) {
 95		ret = -EBUSY;
 96		goto err_alloc;
 97	}
 98
 99	data->membase = ioremap(res.start, size);
100	if (!data->membase) {
101		ret = -ENOMEM;
102		goto err_alloc;
103	}
104
105	spin_lock_init(&data->lock);
106
107	data->rcdev.owner = THIS_MODULE;
108	data->rcdev.nr_resets = size * 32;
109	data->rcdev.ops = &sunxi_reset_ops;
110	data->rcdev.of_node = np;
111
112	return reset_controller_register(&data->rcdev);
113
114err_alloc:
115	kfree(data);
116	return ret;
117};
118
119/*
120 * These are the reset controller we need to initialize early on in
121 * our system, before we can even think of using a regular device
122 * driver for it.
123 */
124static const struct of_device_id sunxi_early_reset_dt_ids[] __initconst = {
125	{ .compatible = "allwinner,sun6i-a31-ahb1-reset", },
126	{ /* sentinel */ },
127};
128
129void __init sun6i_reset_init(void)
130{
131	struct device_node *np;
132
133	for_each_matching_node(np, sunxi_early_reset_dt_ids)
134		sunxi_reset_init(np);
135}
136
137/*
138 * And these are the controllers we can register through the regular
139 * device model.
140 */
141static const struct of_device_id sunxi_reset_dt_ids[] = {
142	 { .compatible = "allwinner,sun6i-a31-clock-reset", },
143	 { /* sentinel */ },
144};
145MODULE_DEVICE_TABLE(of, sunxi_reset_dt_ids);
146
147static int sunxi_reset_probe(struct platform_device *pdev)
148{
149	struct sunxi_reset_data *data;
150	struct resource *res;
151
152	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
153	if (!data)
154		return -ENOMEM;
155
156	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
157	data->membase = devm_ioremap_resource(&pdev->dev, res);
158	if (IS_ERR(data->membase))
159		return PTR_ERR(data->membase);
160
161	spin_lock_init(&data->lock);
162
163	data->rcdev.owner = THIS_MODULE;
164	data->rcdev.nr_resets = resource_size(res) * 32;
165	data->rcdev.ops = &sunxi_reset_ops;
166	data->rcdev.of_node = pdev->dev.of_node;
167
168	return reset_controller_register(&data->rcdev);
169}
170
171static int sunxi_reset_remove(struct platform_device *pdev)
172{
173	struct sunxi_reset_data *data = platform_get_drvdata(pdev);
174
175	reset_controller_unregister(&data->rcdev);
176
177	return 0;
178}
179
180static struct platform_driver sunxi_reset_driver = {
181	.probe	= sunxi_reset_probe,
182	.remove	= sunxi_reset_remove,
183	.driver = {
184		.name		= "sunxi-reset",
185		.of_match_table	= sunxi_reset_dt_ids,
186	},
187};
188module_platform_driver(sunxi_reset_driver);
189
190MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
191MODULE_DESCRIPTION("Allwinner SoCs Reset Controller Driver");
192MODULE_LICENSE("GPL");