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
a10_reset_init(struct device_node * np)22 static 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", ®_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
64 err_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 */
76 static const struct of_device_id socfpga_early_reset_dt_ids[] __initconst = {
77 { .compatible = "altr,rst-mgr", },
78 { /* sentinel */ },
79 };
80
socfpga_reset_init(void)81 void __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 */
96 static const struct of_device_id socfpga_reset_dt_ids[] = {
97 { .compatible = "altr,rst-mgr", },
98 { /* sentinel */ },
99 };
100
reset_simple_probe(struct platform_device * pdev)101 static int reset_simple_probe(struct platform_device *pdev)
102 {
103 return 0;
104 }
105
106 static 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 };
113 builtin_platform_driver(reset_socfpga_driver);
114