1 /*
2  * Hisilicon SoC reset code
3  *
4  * Copyright (c) 2014 Hisilicon Ltd.
5  * Copyright (c) 2014 Linaro Ltd.
6  *
7  * Author: Haojian Zhuang <haojian.zhuang@linaro.org>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  */
13 
14 #include <linux/delay.h>
15 #include <linux/io.h>
16 #include <linux/module.h>
17 #include <linux/notifier.h>
18 #include <linux/of_address.h>
19 #include <linux/platform_device.h>
20 #include <linux/reboot.h>
21 
22 #include <asm/proc-fns.h>
23 
24 static void __iomem *base;
25 static u32 reboot_offset;
26 
27 static int hisi_restart_handler(struct notifier_block *this,
28 				unsigned long mode, void *cmd)
29 {
30 	writel_relaxed(0xdeadbeef, base + reboot_offset);
31 
32 	while (1)
33 		cpu_do_idle();
34 
35 	return NOTIFY_DONE;
36 }
37 
38 static struct notifier_block hisi_restart_nb = {
39 	.notifier_call = hisi_restart_handler,
40 	.priority = 128,
41 };
42 
43 static int hisi_reboot_probe(struct platform_device *pdev)
44 {
45 	struct device_node *np = pdev->dev.of_node;
46 	int err;
47 
48 	base = of_iomap(np, 0);
49 	if (!base) {
50 		WARN(1, "failed to map base address");
51 		return -ENODEV;
52 	}
53 
54 	if (of_property_read_u32(np, "reboot-offset", &reboot_offset) < 0) {
55 		pr_err("failed to find reboot-offset property\n");
56 		iounmap(base);
57 		return -EINVAL;
58 	}
59 
60 	err = register_restart_handler(&hisi_restart_nb);
61 	if (err) {
62 		dev_err(&pdev->dev, "cannot register restart handler (err=%d)\n",
63 			err);
64 		iounmap(base);
65 	}
66 
67 	return err;
68 }
69 
70 static const struct of_device_id hisi_reboot_of_match[] = {
71 	{ .compatible = "hisilicon,sysctrl" },
72 	{}
73 };
74 
75 static struct platform_driver hisi_reboot_driver = {
76 	.probe = hisi_reboot_probe,
77 	.driver = {
78 		.name = "hisi-reboot",
79 		.of_match_table = hisi_reboot_of_match,
80 	},
81 };
82 module_platform_driver(hisi_reboot_driver);
83