1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Renesas R-Mobile Reset Driver |
4 | * |
5 | * Copyright (C) 2014 Glider bvba |
6 | */ |
7 | |
8 | #include <linux/io.h> |
9 | #include <linux/module.h> |
10 | #include <linux/notifier.h> |
11 | #include <linux/of_address.h> |
12 | #include <linux/platform_device.h> |
13 | #include <linux/printk.h> |
14 | #include <linux/reboot.h> |
15 | |
16 | /* SYSC Register Bank 2 */ |
17 | #define RESCNT2 0x20 /* Reset Control Register 2 */ |
18 | |
19 | /* Reset Control Register 2 */ |
20 | #define RESCNT2_PRES 0x80000000 /* Soft power-on reset */ |
21 | |
22 | static void __iomem *sysc_base2; |
23 | |
24 | static int rmobile_reset_handler(struct notifier_block *this, |
25 | unsigned long mode, void *cmd) |
26 | { |
27 | pr_debug("%s %lu\n" , __func__, mode); |
28 | |
29 | /* Let's assume we have acquired the HPB semaphore */ |
30 | writel(RESCNT2_PRES, addr: sysc_base2 + RESCNT2); |
31 | |
32 | return NOTIFY_DONE; |
33 | } |
34 | |
35 | static struct notifier_block rmobile_reset_nb = { |
36 | .notifier_call = rmobile_reset_handler, |
37 | .priority = 192, |
38 | }; |
39 | |
40 | static int rmobile_reset_probe(struct platform_device *pdev) |
41 | { |
42 | int error; |
43 | |
44 | sysc_base2 = of_iomap(node: pdev->dev.of_node, index: 1); |
45 | if (!sysc_base2) |
46 | return -ENODEV; |
47 | |
48 | error = register_restart_handler(&rmobile_reset_nb); |
49 | if (error) { |
50 | dev_err(&pdev->dev, |
51 | "cannot register restart handler (err=%d)\n" , error); |
52 | goto fail_unmap; |
53 | } |
54 | |
55 | return 0; |
56 | |
57 | fail_unmap: |
58 | iounmap(addr: sysc_base2); |
59 | return error; |
60 | } |
61 | |
62 | static int rmobile_reset_remove(struct platform_device *pdev) |
63 | { |
64 | unregister_restart_handler(&rmobile_reset_nb); |
65 | iounmap(addr: sysc_base2); |
66 | return 0; |
67 | } |
68 | |
69 | static const struct of_device_id rmobile_reset_of_match[] = { |
70 | { .compatible = "renesas,sysc-rmobile" , }, |
71 | { /* sentinel */ } |
72 | }; |
73 | MODULE_DEVICE_TABLE(of, rmobile_reset_of_match); |
74 | |
75 | static struct platform_driver rmobile_reset_driver = { |
76 | .probe = rmobile_reset_probe, |
77 | .remove = rmobile_reset_remove, |
78 | .driver = { |
79 | .name = "rmobile_reset" , |
80 | .of_match_table = rmobile_reset_of_match, |
81 | }, |
82 | }; |
83 | |
84 | module_platform_driver(rmobile_reset_driver); |
85 | |
86 | MODULE_DESCRIPTION("Renesas R-Mobile Reset Driver" ); |
87 | MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>" ); |
88 | MODULE_LICENSE("GPL v2" ); |
89 | |