1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * ZTE zx296702 SoC reset code
4 *
5 * Copyright (c) 2015 Linaro Ltd.
6 *
7 * Author: Jun Nie <jun.nie@linaro.org>
8 */
9
10#include <linux/delay.h>
11#include <linux/io.h>
12#include <linux/module.h>
13#include <linux/notifier.h>
14#include <linux/of_address.h>
15#include <linux/platform_device.h>
16#include <linux/reboot.h>
17
18static void __iomem *base;
19static void __iomem *pcu_base;
20
21static int zx_restart_handler(struct notifier_block *this,
22			      unsigned long mode, void *cmd)
23{
24	writel_relaxed(1, base + 0xb0);
25	writel_relaxed(1, pcu_base + 0x34);
26
27	mdelay(50);
28	pr_emerg("Unable to restart system\n");
29
30	return NOTIFY_DONE;
31}
32
33static struct notifier_block zx_restart_nb = {
34	.notifier_call = zx_restart_handler,
35	.priority = 128,
36};
37
38static int zx_reboot_probe(struct platform_device *pdev)
39{
40	struct device_node *np = pdev->dev.of_node;
41	int err;
42
43	base = of_iomap(np, 0);
44	if (!base) {
45		WARN(1, "failed to map base address");
46		return -ENODEV;
47	}
48
49	np = of_find_compatible_node(NULL, NULL, "zte,zx296702-pcu");
50	pcu_base = of_iomap(np, 0);
51	of_node_put(np);
52	if (!pcu_base) {
53		iounmap(base);
54		WARN(1, "failed to map pcu_base address");
55		return -ENODEV;
56	}
57
58	err = register_restart_handler(&zx_restart_nb);
59	if (err) {
60		iounmap(base);
61		iounmap(pcu_base);
62		dev_err(&pdev->dev, "Register restart handler failed(err=%d)\n",
63			err);
64	}
65
66	return err;
67}
68
69static const struct of_device_id zx_reboot_of_match[] = {
70	{ .compatible = "zte,sysctrl" },
71	{}
72};
73MODULE_DEVICE_TABLE(of, zx_reboot_of_match);
74
75static struct platform_driver zx_reboot_driver = {
76	.probe = zx_reboot_probe,
77	.driver = {
78		.name = "zx-reboot",
79		.of_match_table = zx_reboot_of_match,
80	},
81};
82module_platform_driver(zx_reboot_driver);
83
84MODULE_DESCRIPTION("ZTE SoCs reset driver");
85MODULE_AUTHOR("Jun Nie <jun.nie@linaro.org>");
86MODULE_LICENSE("GPL v2");
87