1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2018, Intel Corporation
4 * Copied from reset-sunxi.c
5 */
6
7#include <linux/err.h>
8#include <linux/io.h>
9#include <linux/init.h>
10#include <linux/of.h>
11#include <linux/of_address.h>
12#include <linux/platform_device.h>
13#include <linux/reset-controller.h>
14#include <linux/reset/reset-simple.h>
15#include <linux/reset/socfpga.h>
16#include <linux/slab.h>
17#include <linux/spinlock.h>
18#include <linux/types.h>
19
20#define SOCFPGA_NR_BANKS	8
21
22static int a10_reset_init(struct device_node *np)
23{
24	struct reset_simple_data *data;
25	struct resource res;
26	resource_size_t size;
27	int ret;
28	u32 reg_offset = 0x10;
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	if (of_property_read_u32(np, "altr,modrst-offset", &reg_offset))
51		pr_warn("missing altr,modrst-offset property, assuming 0x10\n");
52	data->membase += reg_offset;
53
54	spin_lock_init(&data->lock);
55
56	data->rcdev.owner = THIS_MODULE;
57	data->rcdev.nr_resets = SOCFPGA_NR_BANKS * 32;
58	data->rcdev.ops = &reset_simple_ops;
59	data->rcdev.of_node = np;
60	data->status_active_low = true;
61
62	return reset_controller_register(&data->rcdev);
63
64err_alloc:
65	kfree(data);
66	return ret;
67};
68
69/*
70 * These are the reset controller we need to initialize early on in
71 * our system, before we can even think of using a regular device
72 * driver for it.
73 * The controllers that we can register through the regular device
74 * model are handled by the simple reset driver directly.
75 */
76static const struct of_device_id socfpga_early_reset_dt_ids[] __initconst = {
77	{ .compatible = "altr,rst-mgr", },
78	{ /* sentinel */ },
79};
80
81void __init socfpga_reset_init(void)
82{
83	struct device_node *np;
84
85	for_each_matching_node(np, socfpga_early_reset_dt_ids)
86		a10_reset_init(np);
87}
88
89/*
90 * The early driver is problematic, because it doesn't register
91 * itself as a driver. This causes certain device links to prevent
92 * consumer devices from probing. The hacky solution is to register
93 * an empty driver, whose only job is to attach itself to the reset
94 * manager and call probe.
95 */
96static const struct of_device_id socfpga_reset_dt_ids[] = {
97	{ .compatible = "altr,rst-mgr", },
98	{ /* sentinel */ },
99};
100
101static int reset_simple_probe(struct platform_device *pdev)
102{
103	return 0;
104}
105
106static struct platform_driver reset_socfpga_driver = {
107	.probe	= reset_simple_probe,
108	.driver = {
109		.name		= "socfpga-reset",
110		.of_match_table	= socfpga_reset_dt_ids,
111	},
112};
113builtin_platform_driver(reset_socfpga_driver);
114