1 /*
2  * Copyright (C) 2013 Broadcom Corporation
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License as
6  * published by the Free Software Foundation version 2.
7  *
8  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
9  * kind, whether express or implied; without even the implied warranty
10  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11  * GNU General Public License for more details.
12  */
13 
14 #include <linux/device.h>
15 #include <linux/errno.h>
16 #include <linux/init.h>
17 #include <linux/io.h>
18 #include <linux/jiffies.h>
19 #include <linux/notifier.h>
20 #include <linux/of_address.h>
21 #include <linux/of_irq.h>
22 #include <linux/of_platform.h>
23 #include <linux/platform_device.h>
24 #include <linux/printk.h>
25 #include <linux/reboot.h>
26 #include <linux/regmap.h>
27 #include <linux/smp.h>
28 #include <linux/mfd/syscon.h>
29 
30 #define RESET_SOURCE_ENABLE_REG 1
31 #define SW_MASTER_RESET_REG 2
32 
33 static struct regmap *regmap;
34 static u32 rst_src_en;
35 static u32 sw_mstr_rst;
36 
37 static int brcmstb_restart_handler(struct notifier_block *this,
38 				   unsigned long mode, void *cmd)
39 {
40 	int rc;
41 	u32 tmp;
42 
43 	rc = regmap_write(regmap, rst_src_en, 1);
44 	if (rc) {
45 		pr_err("failed to write rst_src_en (%d)\n", rc);
46 		return NOTIFY_DONE;
47 	}
48 
49 	rc = regmap_read(regmap, rst_src_en, &tmp);
50 	if (rc) {
51 		pr_err("failed to read rst_src_en (%d)\n", rc);
52 		return NOTIFY_DONE;
53 	}
54 
55 	rc = regmap_write(regmap, sw_mstr_rst, 1);
56 	if (rc) {
57 		pr_err("failed to write sw_mstr_rst (%d)\n", rc);
58 		return NOTIFY_DONE;
59 	}
60 
61 	rc = regmap_read(regmap, sw_mstr_rst, &tmp);
62 	if (rc) {
63 		pr_err("failed to read sw_mstr_rst (%d)\n", rc);
64 		return NOTIFY_DONE;
65 	}
66 
67 	while (1)
68 		;
69 
70 	return NOTIFY_DONE;
71 }
72 
73 static struct notifier_block brcmstb_restart_nb = {
74 	.notifier_call = brcmstb_restart_handler,
75 	.priority = 128,
76 };
77 
78 static int brcmstb_reboot_probe(struct platform_device *pdev)
79 {
80 	int rc;
81 	struct device_node *np = pdev->dev.of_node;
82 
83 	regmap = syscon_regmap_lookup_by_phandle(np, "syscon");
84 	if (IS_ERR(regmap)) {
85 		pr_err("failed to get syscon phandle\n");
86 		return -EINVAL;
87 	}
88 
89 	rc = of_property_read_u32_index(np, "syscon", RESET_SOURCE_ENABLE_REG,
90 					&rst_src_en);
91 	if (rc) {
92 		pr_err("can't get rst_src_en offset (%d)\n", rc);
93 		return -EINVAL;
94 	}
95 
96 	rc = of_property_read_u32_index(np, "syscon", SW_MASTER_RESET_REG,
97 					&sw_mstr_rst);
98 	if (rc) {
99 		pr_err("can't get sw_mstr_rst offset (%d)\n", rc);
100 		return -EINVAL;
101 	}
102 
103 	rc = register_restart_handler(&brcmstb_restart_nb);
104 	if (rc)
105 		dev_err(&pdev->dev,
106 			"cannot register restart handler (err=%d)\n", rc);
107 
108 	return rc;
109 }
110 
111 static const struct of_device_id of_match[] = {
112 	{ .compatible = "brcm,brcmstb-reboot", },
113 	{},
114 };
115 
116 static struct platform_driver brcmstb_reboot_driver = {
117 	.probe = brcmstb_reboot_probe,
118 	.driver = {
119 		.name = "brcmstb-reboot",
120 		.of_match_table = of_match,
121 	},
122 };
123 
124 static int __init brcmstb_reboot_init(void)
125 {
126 	return platform_driver_probe(&brcmstb_reboot_driver,
127 					brcmstb_reboot_probe);
128 }
129 subsys_initcall(brcmstb_reboot_init);
130