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
21static void __iomem *base;
22static u32 reboot_offset;
23
24static 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
35static struct notifier_block hisi_restart_nb = {
36	.notifier_call = hisi_restart_handler,
37	.priority = 128,
38};
39
40static 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
67static const struct of_device_id hisi_reboot_of_match[] = {
68	{ .compatible = "hisilicon,sysctrl" },
69	{}
70};
71MODULE_DEVICE_TABLE(of, hisi_reboot_of_match);
72
73static 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};
80module_platform_driver(hisi_reboot_driver);
81