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