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 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	reset_controller_register(&data->rcdev);
112
113	return 0;
114
115err_alloc:
116	kfree(data);
117	return ret;
118};
119
120/*
121 * These are the reset controller we need to initialize early on in
122 * our system, before we can even think of using a regular device
123 * driver for it.
124 */
125static const struct of_device_id sunxi_early_reset_dt_ids[] __initdata = {
126	{ .compatible = "allwinner,sun6i-a31-ahb1-reset", },
127	{ /* sentinel */ },
128};
129
130void __init sun6i_reset_init(void)
131{
132	struct device_node *np;
133
134	for_each_matching_node(np, sunxi_early_reset_dt_ids)
135		sunxi_reset_init(np);
136}
137
138/*
139 * And these are the controllers we can register through the regular
140 * device model.
141 */
142static const struct of_device_id sunxi_reset_dt_ids[] = {
143	 { .compatible = "allwinner,sun6i-a31-clock-reset", },
144	 { /* sentinel */ },
145};
146MODULE_DEVICE_TABLE(of, sunxi_reset_dt_ids);
147
148static int sunxi_reset_probe(struct platform_device *pdev)
149{
150	struct sunxi_reset_data *data;
151	struct resource *res;
152
153	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
154	if (!data)
155		return -ENOMEM;
156
157	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
158	data->membase = devm_ioremap_resource(&pdev->dev, res);
159	if (IS_ERR(data->membase))
160		return PTR_ERR(data->membase);
161
162	spin_lock_init(&data->lock);
163
164	data->rcdev.owner = THIS_MODULE;
165	data->rcdev.nr_resets = resource_size(res) * 32;
166	data->rcdev.ops = &sunxi_reset_ops;
167	data->rcdev.of_node = pdev->dev.of_node;
168
169	return reset_controller_register(&data->rcdev);
170}
171
172static int sunxi_reset_remove(struct platform_device *pdev)
173{
174	struct sunxi_reset_data *data = platform_get_drvdata(pdev);
175
176	reset_controller_unregister(&data->rcdev);
177
178	return 0;
179}
180
181static struct platform_driver sunxi_reset_driver = {
182	.probe	= sunxi_reset_probe,
183	.remove	= sunxi_reset_remove,
184	.driver = {
185		.name		= "sunxi-reset",
186		.of_match_table	= sunxi_reset_dt_ids,
187	},
188};
189module_platform_driver(sunxi_reset_driver);
190
191MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
192MODULE_DESCRIPTION("Allwinner SoCs Reset Controller Driver");
193MODULE_LICENSE("GPL");
194