1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Allwinner SoCs Reset Controller driver
4  *
5  * Copyright 2013 Maxime Ripard
6  *
7  * Maxime Ripard <maxime.ripard@free-electrons.com>
8  */
9 
10 #include <linux/err.h>
11 #include <linux/io.h>
12 #include <linux/init.h>
13 #include <linux/of.h>
14 #include <linux/of_address.h>
15 #include <linux/platform_device.h>
16 #include <linux/reset-controller.h>
17 #include <linux/reset/reset-simple.h>
18 #include <linux/reset/sunxi.h>
19 #include <linux/slab.h>
20 #include <linux/spinlock.h>
21 #include <linux/types.h>
22 
sunxi_reset_init(struct device_node * np)23 static int sunxi_reset_init(struct device_node *np)
24 {
25 	struct reset_simple_data *data;
26 	struct resource res;
27 	resource_size_t size;
28 	int ret;
29 
30 	data = kzalloc(sizeof(*data), GFP_KERNEL);
31 	if (!data)
32 		return -ENOMEM;
33 
34 	ret = of_address_to_resource(np, 0, &res);
35 	if (ret)
36 		goto err_alloc;
37 
38 	size = resource_size(&res);
39 	if (!request_mem_region(res.start, size, np->name)) {
40 		ret = -EBUSY;
41 		goto err_alloc;
42 	}
43 
44 	data->membase = ioremap(res.start, size);
45 	if (!data->membase) {
46 		ret = -ENOMEM;
47 		goto err_alloc;
48 	}
49 
50 	spin_lock_init(&data->lock);
51 
52 	data->rcdev.owner = THIS_MODULE;
53 	data->rcdev.nr_resets = size * 8;
54 	data->rcdev.ops = &reset_simple_ops;
55 	data->rcdev.of_node = np;
56 	data->active_low = true;
57 
58 	return reset_controller_register(&data->rcdev);
59 
60 err_alloc:
61 	kfree(data);
62 	return ret;
63 };
64 
65 /*
66  * These are the reset controller we need to initialize early on in
67  * our system, before we can even think of using a regular device
68  * driver for it.
69  * The controllers that we can register through the regular device
70  * model are handled by the simple reset driver directly.
71  */
72 static const struct of_device_id sunxi_early_reset_dt_ids[] __initconst = {
73 	{ .compatible = "allwinner,sun6i-a31-ahb1-reset", },
74 	{ /* sentinel */ },
75 };
76 
sun6i_reset_init(void)77 void __init sun6i_reset_init(void)
78 {
79 	struct device_node *np;
80 
81 	for_each_matching_node(np, sunxi_early_reset_dt_ids)
82 		sunxi_reset_init(np);
83 }
84