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 | |
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(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: ®_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 | |
68 | release_region: |
69 | release_mem_region(res.start, size); |
70 | |
71 | err_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 | */ |
83 | static const struct of_device_id socfpga_early_reset_dt_ids[] __initconst = { |
84 | { .compatible = "altr,rst-mgr" , }, |
85 | { /* sentinel */ }, |
86 | }; |
87 | |
88 | void __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 | */ |
103 | static const struct of_device_id socfpga_reset_dt_ids[] = { |
104 | { .compatible = "altr,rst-mgr" , }, |
105 | { /* sentinel */ }, |
106 | }; |
107 | |
108 | static int reset_simple_probe(struct platform_device *pdev) |
109 | { |
110 | return 0; |
111 | } |
112 | |
113 | static 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 | }; |
120 | builtin_platform_driver(reset_socfpga_driver); |
121 | |