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 
17 #define INTEGRATOR_HDR_CTRL_OFFSET	0x0C
18 #define INTEGRATOR_HDR_LOCK_OFFSET	0x14
19 #define INTEGRATOR_CM_CTRL_RESET	(1 << 3)
20 
21 #define REALVIEW_SYS_LOCK_OFFSET	0x20
22 #define REALVIEW_SYS_RESETCTL_OFFSET	0x40
23 
24 /* Magic unlocking token used on all Versatile boards */
25 #define VERSATILE_LOCK_VAL		0xA05F
26 
27 /*
28  * We detect the different syscon types from the compatible strings.
29  */
30 enum versatile_reboot {
31 	INTEGRATOR_REBOOT_CM,
32 	REALVIEW_REBOOT_EB,
33 	REALVIEW_REBOOT_PB1176,
34 	REALVIEW_REBOOT_PB11MP,
35 	REALVIEW_REBOOT_PBA8,
36 	REALVIEW_REBOOT_PBX,
37 };
38 
39 /* Pointer to the system controller */
40 static struct regmap *syscon_regmap;
41 static enum versatile_reboot versatile_reboot_type;
42 
43 static const struct of_device_id versatile_reboot_of_match[] = {
44 	{
45 		.compatible = "arm,core-module-integrator",
46 		.data = (void *)INTEGRATOR_REBOOT_CM
47 	},
48 	{
49 		.compatible = "arm,realview-eb-syscon",
50 		.data = (void *)REALVIEW_REBOOT_EB,
51 	},
52 	{
53 		.compatible = "arm,realview-pb1176-syscon",
54 		.data = (void *)REALVIEW_REBOOT_PB1176,
55 	},
56 	{
57 		.compatible = "arm,realview-pb11mp-syscon",
58 		.data = (void *)REALVIEW_REBOOT_PB11MP,
59 	},
60 	{
61 		.compatible = "arm,realview-pba8-syscon",
62 		.data = (void *)REALVIEW_REBOOT_PBA8,
63 	},
64 	{
65 		.compatible = "arm,realview-pbx-syscon",
66 		.data = (void *)REALVIEW_REBOOT_PBX,
67 	},
68 	{},
69 };
70 
71 static int versatile_reboot(struct notifier_block *this, unsigned long mode,
72 			    void *cmd)
73 {
74 	/* Unlock the reset register */
75 	/* Then hit reset on the different machines */
76 	switch (versatile_reboot_type) {
77 	case INTEGRATOR_REBOOT_CM:
78 		regmap_write(syscon_regmap, INTEGRATOR_HDR_LOCK_OFFSET,
79 			     VERSATILE_LOCK_VAL);
80 		regmap_update_bits(syscon_regmap,
81 				   INTEGRATOR_HDR_CTRL_OFFSET,
82 				   INTEGRATOR_CM_CTRL_RESET,
83 				   INTEGRATOR_CM_CTRL_RESET);
84 		break;
85 	case REALVIEW_REBOOT_EB:
86 		regmap_write(syscon_regmap, REALVIEW_SYS_LOCK_OFFSET,
87 			     VERSATILE_LOCK_VAL);
88 		regmap_write(syscon_regmap,
89 			     REALVIEW_SYS_RESETCTL_OFFSET, 0x0008);
90 		break;
91 	case REALVIEW_REBOOT_PB1176:
92 		regmap_write(syscon_regmap, REALVIEW_SYS_LOCK_OFFSET,
93 			     VERSATILE_LOCK_VAL);
94 		regmap_write(syscon_regmap,
95 			     REALVIEW_SYS_RESETCTL_OFFSET, 0x0100);
96 		break;
97 	case REALVIEW_REBOOT_PB11MP:
98 	case REALVIEW_REBOOT_PBA8:
99 		regmap_write(syscon_regmap, REALVIEW_SYS_LOCK_OFFSET,
100 			     VERSATILE_LOCK_VAL);
101 		regmap_write(syscon_regmap, REALVIEW_SYS_RESETCTL_OFFSET,
102 			     0x0000);
103 		regmap_write(syscon_regmap, REALVIEW_SYS_RESETCTL_OFFSET,
104 			     0x0004);
105 		break;
106 	case REALVIEW_REBOOT_PBX:
107 		regmap_write(syscon_regmap, REALVIEW_SYS_LOCK_OFFSET,
108 			     VERSATILE_LOCK_VAL);
109 		regmap_write(syscon_regmap, REALVIEW_SYS_RESETCTL_OFFSET,
110 			     0x00f0);
111 		regmap_write(syscon_regmap, REALVIEW_SYS_RESETCTL_OFFSET,
112 			     0x00f4);
113 		break;
114 	}
115 	dsb();
116 
117 	return NOTIFY_DONE;
118 }
119 
120 static struct notifier_block versatile_reboot_nb = {
121 	.notifier_call = versatile_reboot,
122 	.priority = 192,
123 };
124 
125 static int __init versatile_reboot_probe(void)
126 {
127 	const struct of_device_id *reboot_id;
128 	struct device_node *np;
129 	int err;
130 
131 	np = of_find_matching_node_and_match(NULL, versatile_reboot_of_match,
132 						 &reboot_id);
133 	if (!np)
134 		return -ENODEV;
135 	versatile_reboot_type = (enum versatile_reboot)reboot_id->data;
136 
137 	syscon_regmap = syscon_node_to_regmap(np);
138 	if (IS_ERR(syscon_regmap))
139 		return PTR_ERR(syscon_regmap);
140 
141 	err = register_restart_handler(&versatile_reboot_nb);
142 	if (err)
143 		return err;
144 
145 	pr_info("versatile reboot driver registered\n");
146 	return 0;
147 }
148 device_initcall(versatile_reboot_probe);
149