1 /*
2  * Copyright (C) 2014 Linaro Ltd.
3  *
4  * Author: Linus Walleij <linus.walleij@linaro.org>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2, as
8  * published by the Free Software Foundation.
9  *
10  */
11 #include <linux/init.h>
12 #include <linux/mfd/syscon.h>
13 #include <linux/reboot.h>
14 #include <linux/regmap.h>
15 #include <linux/of.h>
16 #include <asm/system_misc.h>
17 
18 #define REALVIEW_SYS_LOCK_OFFSET	0x20
19 #define REALVIEW_SYS_LOCK_VAL		0xA05F
20 #define REALVIEW_SYS_RESETCTL_OFFSET	0x40
21 
22 /*
23  * We detect the different syscon types from the compatible strings.
24  */
25 enum versatile_reboot {
26 	REALVIEW_REBOOT_EB,
27 	REALVIEW_REBOOT_PB1176,
28 	REALVIEW_REBOOT_PB11MP,
29 	REALVIEW_REBOOT_PBA8,
30 	REALVIEW_REBOOT_PBX,
31 };
32 
33 /* Pointer to the system controller */
34 static struct regmap *syscon_regmap;
35 static enum versatile_reboot versatile_reboot_type;
36 
37 static const struct of_device_id versatile_reboot_of_match[] = {
38 	{
39 		.compatible = "arm,realview-eb-syscon",
40 		.data = (void *)REALVIEW_REBOOT_EB,
41 	},
42 	{
43 		.compatible = "arm,realview-pb1176-syscon",
44 		.data = (void *)REALVIEW_REBOOT_PB1176,
45 	},
46 	{
47 		.compatible = "arm,realview-pb11mp-syscon",
48 		.data = (void *)REALVIEW_REBOOT_PB11MP,
49 	},
50 	{
51 		.compatible = "arm,realview-pba8-syscon",
52 		.data = (void *)REALVIEW_REBOOT_PBA8,
53 	},
54 	{
55 		.compatible = "arm,realview-pbx-syscon",
56 		.data = (void *)REALVIEW_REBOOT_PBX,
57 	},
58 };
59 
60 static void versatile_reboot(enum reboot_mode mode, const char *cmd)
61 {
62 	/* Unlock the reset register */
63 	regmap_write(syscon_regmap, REALVIEW_SYS_LOCK_OFFSET,
64 		     REALVIEW_SYS_LOCK_VAL);
65 	/* Then hit reset on the different machines */
66 	switch (versatile_reboot_type) {
67 	case REALVIEW_REBOOT_EB:
68 		regmap_write(syscon_regmap,
69 			     REALVIEW_SYS_RESETCTL_OFFSET, 0x0008);
70 		break;
71 	case REALVIEW_REBOOT_PB1176:
72 		regmap_write(syscon_regmap,
73 			     REALVIEW_SYS_RESETCTL_OFFSET, 0x0100);
74 		break;
75 	case REALVIEW_REBOOT_PB11MP:
76 	case REALVIEW_REBOOT_PBA8:
77 		regmap_write(syscon_regmap, REALVIEW_SYS_RESETCTL_OFFSET,
78 			     0x0000);
79 		regmap_write(syscon_regmap, REALVIEW_SYS_RESETCTL_OFFSET,
80 			     0x0004);
81 		break;
82 	case REALVIEW_REBOOT_PBX:
83 		regmap_write(syscon_regmap, REALVIEW_SYS_RESETCTL_OFFSET,
84 			     0x00f0);
85 		regmap_write(syscon_regmap, REALVIEW_SYS_RESETCTL_OFFSET,
86 			     0x00f4);
87 		break;
88 	}
89 	dsb();
90 }
91 
92 static int __init versatile_reboot_probe(void)
93 {
94 	const struct of_device_id *reboot_id;
95 	struct device_node *np;
96 
97 	np = of_find_matching_node_and_match(NULL, versatile_reboot_of_match,
98 						 &reboot_id);
99 	if (!np)
100 		return -ENODEV;
101 	versatile_reboot_type = (enum versatile_reboot)reboot_id->data;
102 
103 	syscon_regmap = syscon_node_to_regmap(np);
104 	if (IS_ERR(syscon_regmap))
105 		return PTR_ERR(syscon_regmap);
106 
107 	arm_pm_restart = versatile_reboot;
108 	pr_info("versatile reboot driver registered\n");
109 	return 0;
110 }
111 device_initcall(versatile_reboot_probe);
112