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1 | /* |
2 | * Copyright (C) 2014 Marvell Technology Group Ltd. | |
3 | * | |
4 | * Antoine Tenart <antoine.tenart@free-electrons.com> | |
5 | * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com> | |
6 | * | |
7 | * This file is licensed under the terms of the GNU General Public | |
8 | * License version 2. This program is licensed "as is" without any | |
9 | * warranty of any kind, whether express or implied. | |
10 | */ | |
11 | ||
12 | #include <linux/delay.h> | |
13 | #include <linux/io.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/of.h> | |
16 | #include <linux/of_address.h> | |
17 | #include <linux/platform_device.h> | |
18 | #include <linux/reset-controller.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/types.h> | |
21 | ||
22 | #define BERLIN_MAX_RESETS 32 | |
23 | ||
24 | #define to_berlin_reset_priv(p) \ | |
25 | container_of((p), struct berlin_reset_priv, rcdev) | |
26 | ||
27 | struct berlin_reset_priv { | |
28 | void __iomem *base; | |
29 | unsigned int size; | |
30 | struct reset_controller_dev rcdev; | |
31 | }; | |
32 | ||
33 | static int berlin_reset_reset(struct reset_controller_dev *rcdev, | |
34 | unsigned long id) | |
35 | { | |
36 | struct berlin_reset_priv *priv = to_berlin_reset_priv(rcdev); | |
37 | int offset = id >> 8; | |
38 | int mask = BIT(id & 0x1f); | |
39 | ||
40 | writel(mask, priv->base + offset); | |
41 | ||
42 | /* let the reset be effective */ | |
43 | udelay(10); | |
44 | ||
45 | return 0; | |
46 | } | |
47 | ||
48 | static struct reset_control_ops berlin_reset_ops = { | |
49 | .reset = berlin_reset_reset, | |
50 | }; | |
51 | ||
52 | static int berlin_reset_xlate(struct reset_controller_dev *rcdev, | |
53 | const struct of_phandle_args *reset_spec) | |
54 | { | |
55 | struct berlin_reset_priv *priv = to_berlin_reset_priv(rcdev); | |
56 | unsigned offset, bit; | |
57 | ||
58 | if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells)) | |
59 | return -EINVAL; | |
60 | ||
61 | offset = reset_spec->args[0]; | |
62 | bit = reset_spec->args[1]; | |
63 | ||
64 | if (offset >= priv->size) | |
65 | return -EINVAL; | |
66 | ||
67 | if (bit >= BERLIN_MAX_RESETS) | |
68 | return -EINVAL; | |
69 | ||
70 | return (offset << 8) | bit; | |
71 | } | |
72 | ||
73 | static int __berlin_reset_init(struct device_node *np) | |
74 | { | |
75 | struct berlin_reset_priv *priv; | |
76 | struct resource res; | |
77 | resource_size_t size; | |
78 | int ret; | |
79 | ||
80 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); | |
81 | if (!priv) | |
82 | return -ENOMEM; | |
83 | ||
84 | ret = of_address_to_resource(np, 0, &res); | |
85 | if (ret) | |
86 | goto err; | |
87 | ||
88 | size = resource_size(&res); | |
89 | priv->base = ioremap(res.start, size); | |
90 | if (!priv->base) { | |
91 | ret = -ENOMEM; | |
92 | goto err; | |
93 | } | |
94 | priv->size = size; | |
95 | ||
96 | priv->rcdev.owner = THIS_MODULE; | |
97 | priv->rcdev.ops = &berlin_reset_ops; | |
98 | priv->rcdev.of_node = np; | |
99 | priv->rcdev.of_reset_n_cells = 2; | |
100 | priv->rcdev.of_xlate = berlin_reset_xlate; | |
101 | ||
102 | reset_controller_register(&priv->rcdev); | |
103 | ||
104 | return 0; | |
105 | ||
106 | err: | |
107 | kfree(priv); | |
108 | return ret; | |
109 | } | |
110 | ||
111 | static const struct of_device_id berlin_reset_of_match[] __initconst = { | |
112 | { .compatible = "marvell,berlin2-chip-ctrl" }, | |
113 | { .compatible = "marvell,berlin2cd-chip-ctrl" }, | |
114 | { .compatible = "marvell,berlin2q-chip-ctrl" }, | |
115 | { }, | |
116 | }; | |
117 | ||
118 | static int __init berlin_reset_init(void) | |
119 | { | |
120 | struct device_node *np; | |
121 | int ret; | |
122 | ||
123 | for_each_matching_node(np, berlin_reset_of_match) { | |
124 | ret = __berlin_reset_init(np); | |
125 | if (ret) | |
126 | return ret; | |
127 | } | |
128 | ||
129 | return 0; | |
130 | } | |
131 | arch_initcall(berlin_reset_init); |