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/of_address.h>
18 #include <linux/platform_device.h>
19 #include <linux/reboot.h>
20 
21 #include <asm/proc-fns.h>
22 #include <asm/system_misc.h>
23 
24 static void __iomem *base;
25 static u32 reboot_offset;
26 
27 static void hisi_restart(enum reboot_mode mode, const char *cmd)
28 {
29 	writel_relaxed(0xdeadbeef, base + reboot_offset);
30 
31 	while (1)
32 		cpu_do_idle();
33 }
34 
35 static int hisi_reboot_probe(struct platform_device *pdev)
36 {
37 	struct device_node *np = pdev->dev.of_node;
38 
39 	base = of_iomap(np, 0);
40 	if (!base) {
41 		WARN(1, "failed to map base address");
42 		return -ENODEV;
43 	}
44 
45 	if (of_property_read_u32(np, "reboot-offset", &reboot_offset) < 0) {
46 		pr_err("failed to find reboot-offset property\n");
47 		return -EINVAL;
48 	}
49 
50 	arm_pm_restart = hisi_restart;
51 
52 	return 0;
53 }
54 
55 static struct of_device_id hisi_reboot_of_match[] = {
56 	{ .compatible = "hisilicon,sysctrl" },
57 	{}
58 };
59 
60 static struct platform_driver hisi_reboot_driver = {
61 	.probe = hisi_reboot_probe,
62 	.driver = {
63 		.name = "hisi-reboot",
64 		.of_match_table = hisi_reboot_of_match,
65 	},
66 };
67 module_platform_driver(hisi_reboot_driver);
68