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8f1ae77f MR |
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 | ||
25 | struct sunxi_reset_data { | |
26 | spinlock_t lock; | |
27 | void __iomem *membase; | |
28 | struct reset_controller_dev rcdev; | |
29 | }; | |
30 | ||
31 | static 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 | ||
52 | static 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 | ||
73 | static struct reset_control_ops sunxi_reset_ops = { | |
74 | .assert = sunxi_reset_assert, | |
75 | .deassert = sunxi_reset_deassert, | |
76 | }; | |
77 | ||
78 | static 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 | ||
113 | err_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 | */ | |
123 | static const struct of_device_id sunxi_early_reset_dt_ids[] __initdata = { | |
124 | { .compatible = "allwinner,sun6i-a31-ahb1-reset", }, | |
125 | { /* sentinel */ }, | |
126 | }; | |
127 | ||
128 | void __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 | */ | |
140 | static const struct of_device_id sunxi_reset_dt_ids[] = { | |
141 | { .compatible = "allwinner,sun6i-a31-clock-reset", }, | |
142 | { /* sentinel */ }, | |
143 | }; | |
144 | MODULE_DEVICE_TABLE(of, sunxi_reset_dt_ids); | |
145 | ||
146 | static int sunxi_reset_probe(struct platform_device *pdev) | |
147 | { | |
148 | return sunxi_reset_init(pdev->dev.of_node); | |
149 | } | |
150 | ||
151 | static 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 | ||
162 | static 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 | }; | |
171 | module_platform_driver(sunxi_reset_driver); | |
172 | ||
173 | MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com"); | |
174 | MODULE_DESCRIPTION("Allwinner SoCs Reset Controller Driver"); | |
175 | MODULE_LICENSE("GPL"); |