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(size: sizeof(*data), GFP_KERNEL);
31 if (!data)
32 return -ENOMEM;
33
34 ret = of_address_to_resource(dev: np, index: 0, r: &res);
35 if (ret)
36 goto err_alloc;
37
38 size = resource_size(res: &res);
39 if (!request_mem_region(res.start, size, np->name)) {
40 ret = -EBUSY;
41 goto err_alloc;
42 }
43
44 data->membase = ioremap(offset: res.start, size);
45 if (!data->membase) {
46 ret = -ENOMEM;
47 goto release_region;
48 }
49
50 if (of_property_read_u32(np, propname: "altr,modrst-offset", out_value: &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 ret = reset_controller_register(rcdev: &data->rcdev);
63 if (ret)
64 pr_err("unable to register device\n");
65
66 return ret;
67
68release_region:
69 release_mem_region(res.start, size);
70
71err_alloc:
72 kfree(objp: data);
73 return ret;
74};
75
76/*
77 * These are the reset controller we need to initialize early on in
78 * our system, before we can even think of using a regular device
79 * driver for it.
80 * The controllers that we can register through the regular device
81 * model are handled by the simple reset driver directly.
82 */
83static const struct of_device_id socfpga_early_reset_dt_ids[] __initconst = {
84 { .compatible = "altr,rst-mgr", },
85 { /* sentinel */ },
86};
87
88void __init socfpga_reset_init(void)
89{
90 struct device_node *np;
91
92 for_each_matching_node(np, socfpga_early_reset_dt_ids)
93 a10_reset_init(np);
94}
95
96/*
97 * The early driver is problematic, because it doesn't register
98 * itself as a driver. This causes certain device links to prevent
99 * consumer devices from probing. The hacky solution is to register
100 * an empty driver, whose only job is to attach itself to the reset
101 * manager and call probe.
102 */
103static const struct of_device_id socfpga_reset_dt_ids[] = {
104 { .compatible = "altr,rst-mgr", },
105 { /* sentinel */ },
106};
107
108static int reset_simple_probe(struct platform_device *pdev)
109{
110 return 0;
111}
112
113static struct platform_driver reset_socfpga_driver = {
114 .probe = reset_simple_probe,
115 .driver = {
116 .name = "socfpga-reset",
117 .of_match_table = socfpga_reset_dt_ids,
118 },
119};
120builtin_platform_driver(reset_socfpga_driver);
121

source code of linux/drivers/reset/reset-socfpga.c