xref: /openbmc/linux/drivers/reset/reset-sunxi.c (revision d2999e1b)
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 	struct sunxi_reset_data *data;
149 	struct resource *res;
150 
151 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
152 	if (!data)
153 		return -ENOMEM;
154 
155 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
156 	data->membase = devm_ioremap_resource(&pdev->dev, res);
157 	if (IS_ERR(data->membase))
158 		return PTR_ERR(data->membase);
159 
160 	data->rcdev.owner = THIS_MODULE;
161 	data->rcdev.nr_resets = resource_size(res) * 32;
162 	data->rcdev.ops = &sunxi_reset_ops;
163 	data->rcdev.of_node = pdev->dev.of_node;
164 
165 	return reset_controller_register(&data->rcdev);
166 }
167 
168 static int sunxi_reset_remove(struct platform_device *pdev)
169 {
170 	struct sunxi_reset_data *data = platform_get_drvdata(pdev);
171 
172 	reset_controller_unregister(&data->rcdev);
173 
174 	return 0;
175 }
176 
177 static struct platform_driver sunxi_reset_driver = {
178 	.probe	= sunxi_reset_probe,
179 	.remove	= sunxi_reset_remove,
180 	.driver = {
181 		.name		= "sunxi-reset",
182 		.owner		= THIS_MODULE,
183 		.of_match_table	= sunxi_reset_dt_ids,
184 	},
185 };
186 module_platform_driver(sunxi_reset_driver);
187 
188 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
189 MODULE_DESCRIPTION("Allwinner SoCs Reset Controller Driver");
190 MODULE_LICENSE("GPL");
191