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/bitops.h>
15 #include <linux/device.h>
16 #include <linux/errno.h>
17 #include <linux/init.h>
18 #include <linux/io.h>
19 #include <linux/jiffies.h>
20 #include <linux/notifier.h>
21 #include <linux/of_address.h>
22 #include <linux/of_irq.h>
23 #include <linux/of_platform.h>
24 #include <linux/platform_device.h>
25 #include <linux/printk.h>
26 #include <linux/reboot.h>
27 #include <linux/regmap.h>
28 #include <linux/smp.h>
29 #include <linux/mfd/syscon.h>
30 
31 #define RESET_SOURCE_ENABLE_REG 1
32 #define SW_MASTER_RESET_REG 2
33 
34 static struct regmap *regmap;
35 static u32 rst_src_en;
36 static u32 sw_mstr_rst;
37 
38 struct reset_reg_mask {
39 	u32 rst_src_en_mask;
40 	u32 sw_mstr_rst_mask;
41 };
42 
43 static const struct reset_reg_mask *reset_masks;
44 
45 static int brcmstb_restart_handler(struct notifier_block *this,
46 				   unsigned long mode, void *cmd)
47 {
48 	int rc;
49 	u32 tmp;
50 
51 	rc = regmap_write(regmap, rst_src_en, reset_masks->rst_src_en_mask);
52 	if (rc) {
53 		pr_err("failed to write rst_src_en (%d)\n", rc);
54 		return NOTIFY_DONE;
55 	}
56 
57 	rc = regmap_read(regmap, rst_src_en, &tmp);
58 	if (rc) {
59 		pr_err("failed to read rst_src_en (%d)\n", rc);
60 		return NOTIFY_DONE;
61 	}
62 
63 	rc = regmap_write(regmap, sw_mstr_rst, reset_masks->sw_mstr_rst_mask);
64 	if (rc) {
65 		pr_err("failed to write sw_mstr_rst (%d)\n", rc);
66 		return NOTIFY_DONE;
67 	}
68 
69 	rc = regmap_read(regmap, sw_mstr_rst, &tmp);
70 	if (rc) {
71 		pr_err("failed to read sw_mstr_rst (%d)\n", rc);
72 		return NOTIFY_DONE;
73 	}
74 
75 	while (1)
76 		;
77 
78 	return NOTIFY_DONE;
79 }
80 
81 static struct notifier_block brcmstb_restart_nb = {
82 	.notifier_call = brcmstb_restart_handler,
83 	.priority = 128,
84 };
85 
86 static const struct reset_reg_mask reset_bits_40nm = {
87 	.rst_src_en_mask = BIT(0),
88 	.sw_mstr_rst_mask = BIT(0),
89 };
90 
91 static const struct reset_reg_mask reset_bits_65nm = {
92 	.rst_src_en_mask = BIT(3),
93 	.sw_mstr_rst_mask = BIT(31),
94 };
95 
96 static const struct of_device_id of_match[] = {
97 	{ .compatible = "brcm,brcmstb-reboot", .data = &reset_bits_40nm },
98 	{ .compatible = "brcm,bcm7038-reboot", .data = &reset_bits_65nm },
99 	{},
100 };
101 
102 static int brcmstb_reboot_probe(struct platform_device *pdev)
103 {
104 	int rc;
105 	struct device_node *np = pdev->dev.of_node;
106 	const struct of_device_id *of_id;
107 
108 	of_id = of_match_node(of_match, np);
109 	if (!of_id) {
110 		pr_err("failed to look up compatible string\n");
111 		return -EINVAL;
112 	}
113 	reset_masks = of_id->data;
114 
115 	regmap = syscon_regmap_lookup_by_phandle(np, "syscon");
116 	if (IS_ERR(regmap)) {
117 		pr_err("failed to get syscon phandle\n");
118 		return -EINVAL;
119 	}
120 
121 	rc = of_property_read_u32_index(np, "syscon", RESET_SOURCE_ENABLE_REG,
122 					&rst_src_en);
123 	if (rc) {
124 		pr_err("can't get rst_src_en offset (%d)\n", rc);
125 		return -EINVAL;
126 	}
127 
128 	rc = of_property_read_u32_index(np, "syscon", SW_MASTER_RESET_REG,
129 					&sw_mstr_rst);
130 	if (rc) {
131 		pr_err("can't get sw_mstr_rst offset (%d)\n", rc);
132 		return -EINVAL;
133 	}
134 
135 	rc = register_restart_handler(&brcmstb_restart_nb);
136 	if (rc)
137 		dev_err(&pdev->dev,
138 			"cannot register restart handler (err=%d)\n", rc);
139 
140 	return rc;
141 }
142 
143 static struct platform_driver brcmstb_reboot_driver = {
144 	.probe = brcmstb_reboot_probe,
145 	.driver = {
146 		.name = "brcmstb-reboot",
147 		.of_match_table = of_match,
148 	},
149 };
150 
151 static int __init brcmstb_reboot_init(void)
152 {
153 	return platform_driver_probe(&brcmstb_reboot_driver,
154 					brcmstb_reboot_probe);
155 }
156 subsys_initcall(brcmstb_reboot_init);
157