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 VERSATILE_SYS_LOCK_OFFSET	0x20
22 #define VERSATILE_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 	VERSATILE_REBOOT_CM,
33 	REALVIEW_REBOOT_EB,
34 	REALVIEW_REBOOT_PB1176,
35 	REALVIEW_REBOOT_PB11MP,
36 	REALVIEW_REBOOT_PBA8,
37 	REALVIEW_REBOOT_PBX,
38 };
39 
40 /* Pointer to the system controller */
41 static struct regmap *syscon_regmap;
42 static enum versatile_reboot versatile_reboot_type;
43 
44 static const struct of_device_id versatile_reboot_of_match[] = {
45 	{
46 		.compatible = "arm,core-module-integrator",
47 		.data = (void *)INTEGRATOR_REBOOT_CM
48 	},
49 	{
50 		.compatible = "arm,core-module-versatile",
51 		.data = (void *)VERSATILE_REBOOT_CM,
52 	},
53 	{
54 		.compatible = "arm,realview-eb-syscon",
55 		.data = (void *)REALVIEW_REBOOT_EB,
56 	},
57 	{
58 		.compatible = "arm,realview-pb1176-syscon",
59 		.data = (void *)REALVIEW_REBOOT_PB1176,
60 	},
61 	{
62 		.compatible = "arm,realview-pb11mp-syscon",
63 		.data = (void *)REALVIEW_REBOOT_PB11MP,
64 	},
65 	{
66 		.compatible = "arm,realview-pba8-syscon",
67 		.data = (void *)REALVIEW_REBOOT_PBA8,
68 	},
69 	{
70 		.compatible = "arm,realview-pbx-syscon",
71 		.data = (void *)REALVIEW_REBOOT_PBX,
72 	},
73 	{},
74 };
75 
76 static int versatile_reboot(struct notifier_block *this, unsigned long mode,
77 			    void *cmd)
78 {
79 	/* Unlock the reset register */
80 	/* Then hit reset on the different machines */
81 	switch (versatile_reboot_type) {
82 	case INTEGRATOR_REBOOT_CM:
83 		regmap_write(syscon_regmap, INTEGRATOR_HDR_LOCK_OFFSET,
84 			     VERSATILE_LOCK_VAL);
85 		regmap_update_bits(syscon_regmap,
86 				   INTEGRATOR_HDR_CTRL_OFFSET,
87 				   INTEGRATOR_CM_CTRL_RESET,
88 				   INTEGRATOR_CM_CTRL_RESET);
89 		break;
90 	case VERSATILE_REBOOT_CM:
91 		regmap_write(syscon_regmap, VERSATILE_SYS_LOCK_OFFSET,
92 			     VERSATILE_LOCK_VAL);
93 		regmap_update_bits(syscon_regmap,
94 				   VERSATILE_SYS_RESETCTL_OFFSET,
95 				   0x0107,
96 				   0x0105);
97 		regmap_write(syscon_regmap, VERSATILE_SYS_LOCK_OFFSET,
98 			     0);
99 		break;
100 	case REALVIEW_REBOOT_EB:
101 		regmap_write(syscon_regmap, VERSATILE_SYS_LOCK_OFFSET,
102 			     VERSATILE_LOCK_VAL);
103 		regmap_write(syscon_regmap,
104 			     VERSATILE_SYS_RESETCTL_OFFSET, 0x0008);
105 		break;
106 	case REALVIEW_REBOOT_PB1176:
107 		regmap_write(syscon_regmap, VERSATILE_SYS_LOCK_OFFSET,
108 			     VERSATILE_LOCK_VAL);
109 		regmap_write(syscon_regmap,
110 			     VERSATILE_SYS_RESETCTL_OFFSET, 0x0100);
111 		break;
112 	case REALVIEW_REBOOT_PB11MP:
113 	case REALVIEW_REBOOT_PBA8:
114 		regmap_write(syscon_regmap, VERSATILE_SYS_LOCK_OFFSET,
115 			     VERSATILE_LOCK_VAL);
116 		regmap_write(syscon_regmap, VERSATILE_SYS_RESETCTL_OFFSET,
117 			     0x0000);
118 		regmap_write(syscon_regmap, VERSATILE_SYS_RESETCTL_OFFSET,
119 			     0x0004);
120 		break;
121 	case REALVIEW_REBOOT_PBX:
122 		regmap_write(syscon_regmap, VERSATILE_SYS_LOCK_OFFSET,
123 			     VERSATILE_LOCK_VAL);
124 		regmap_write(syscon_regmap, VERSATILE_SYS_RESETCTL_OFFSET,
125 			     0x00f0);
126 		regmap_write(syscon_regmap, VERSATILE_SYS_RESETCTL_OFFSET,
127 			     0x00f4);
128 		break;
129 	}
130 	dsb();
131 
132 	return NOTIFY_DONE;
133 }
134 
135 static struct notifier_block versatile_reboot_nb = {
136 	.notifier_call = versatile_reboot,
137 	.priority = 192,
138 };
139 
140 static int __init versatile_reboot_probe(void)
141 {
142 	const struct of_device_id *reboot_id;
143 	struct device_node *np;
144 	int err;
145 
146 	np = of_find_matching_node_and_match(NULL, versatile_reboot_of_match,
147 						 &reboot_id);
148 	if (!np)
149 		return -ENODEV;
150 	versatile_reboot_type = (enum versatile_reboot)reboot_id->data;
151 
152 	syscon_regmap = syscon_node_to_regmap(np);
153 	if (IS_ERR(syscon_regmap))
154 		return PTR_ERR(syscon_regmap);
155 
156 	err = register_restart_handler(&versatile_reboot_nb);
157 	if (err)
158 		return err;
159 
160 	pr_info("versatile reboot driver registered\n");
161 	return 0;
162 }
163 device_initcall(versatile_reboot_probe);
164