1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * HiSilicon SoC reset code
4 *
5 * Copyright (c) 2014 HiSilicon Ltd.
6 * Copyright (c) 2014 Linaro Ltd.
7 *
8 * Author: Haojian Zhuang <haojian.zhuang@linaro.org>
9 */
10
11 #include <linux/delay.h>
12 #include <linux/io.h>
13 #include <linux/module.h>
14 #include <linux/notifier.h>
15 #include <linux/of_address.h>
16 #include <linux/platform_device.h>
17 #include <linux/reboot.h>
18
19 #include <asm/proc-fns.h>
20
21 static void __iomem *base;
22 static u32 reboot_offset;
23
hisi_restart_handler(struct notifier_block * this,unsigned long mode,void * cmd)24 static int hisi_restart_handler(struct notifier_block *this,
25 unsigned long mode, void *cmd)
26 {
27 writel_relaxed(0xdeadbeef, base + reboot_offset);
28
29 while (1)
30 cpu_do_idle();
31
32 return NOTIFY_DONE;
33 }
34
35 static struct notifier_block hisi_restart_nb = {
36 .notifier_call = hisi_restart_handler,
37 .priority = 128,
38 };
39
hisi_reboot_probe(struct platform_device * pdev)40 static int hisi_reboot_probe(struct platform_device *pdev)
41 {
42 struct device_node *np = pdev->dev.of_node;
43 int err;
44
45 base = of_iomap(np, 0);
46 if (!base) {
47 WARN(1, "failed to map base address");
48 return -ENODEV;
49 }
50
51 if (of_property_read_u32(np, "reboot-offset", &reboot_offset) < 0) {
52 pr_err("failed to find reboot-offset property\n");
53 iounmap(base);
54 return -EINVAL;
55 }
56
57 err = register_restart_handler(&hisi_restart_nb);
58 if (err) {
59 dev_err(&pdev->dev, "cannot register restart handler (err=%d)\n",
60 err);
61 iounmap(base);
62 }
63
64 return err;
65 }
66
67 static const struct of_device_id hisi_reboot_of_match[] = {
68 { .compatible = "hisilicon,sysctrl" },
69 {}
70 };
71 MODULE_DEVICE_TABLE(of, hisi_reboot_of_match);
72
73 static struct platform_driver hisi_reboot_driver = {
74 .probe = hisi_reboot_probe,
75 .driver = {
76 .name = "hisi-reboot",
77 .of_match_table = hisi_reboot_of_match,
78 },
79 };
80 module_platform_driver(hisi_reboot_driver);
81