blob: 695bd3496eba2d82a18f294ac79925f4a3b1cdf1 [file] [log] [blame]
Maxime Ripard8f1ae772013-09-24 11:07:43 +03001/*
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 data->rcdev.owner = THIS_MODULE;
106 data->rcdev.nr_resets = size * 32;
107 data->rcdev.ops = &sunxi_reset_ops;
108 data->rcdev.of_node = np;
109 reset_controller_register(&data->rcdev);
110
111 return 0;
112
113err_alloc:
114 kfree(data);
115 return ret;
116};
117
118/*
119 * These are the reset controller we need to initialize early on in
120 * our system, before we can even think of using a regular device
121 * driver for it.
122 */
123static const struct of_device_id sunxi_early_reset_dt_ids[] __initdata = {
124 { .compatible = "allwinner,sun6i-a31-ahb1-reset", },
125 { /* sentinel */ },
126};
127
128void __init sun6i_reset_init(void)
129{
130 struct device_node *np;
131
132 for_each_matching_node(np, sunxi_early_reset_dt_ids)
133 sunxi_reset_init(np);
134}
135
136/*
137 * And these are the controllers we can register through the regular
138 * device model.
139 */
140static const struct of_device_id sunxi_reset_dt_ids[] = {
141 { .compatible = "allwinner,sun6i-a31-clock-reset", },
142 { /* sentinel */ },
143};
144MODULE_DEVICE_TABLE(of, sunxi_reset_dt_ids);
145
146static int sunxi_reset_probe(struct platform_device *pdev)
147{
148 return sunxi_reset_init(pdev->dev.of_node);
149}
150
151static int sunxi_reset_remove(struct platform_device *pdev)
152{
153 struct sunxi_reset_data *data = platform_get_drvdata(pdev);
154
155 reset_controller_unregister(&data->rcdev);
156 iounmap(data->membase);
157 kfree(data);
158
159 return 0;
160}
161
162static struct platform_driver sunxi_reset_driver = {
163 .probe = sunxi_reset_probe,
164 .remove = sunxi_reset_remove,
165 .driver = {
166 .name = "sunxi-reset",
167 .owner = THIS_MODULE,
168 .of_match_table = sunxi_reset_dt_ids,
169 },
170};
171module_platform_driver(sunxi_reset_driver);
172
173MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
174MODULE_DESCRIPTION("Allwinner SoCs Reset Controller Driver");
175MODULE_LICENSE("GPL");