1 /*
2 * TI keystone reboot driver
3 *
4 * Copyright (C) 2014 Texas Instruments Incorporated. http://www.ti.com/
5 *
6 * Author: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13 #include <linux/io.h>
14 #include <linux/module.h>
15 #include <linux/notifier.h>
16 #include <linux/reboot.h>
17 #include <linux/regmap.h>
18 #include <linux/mfd/syscon.h>
19 #include <linux/of_platform.h>
20
21 #define RSTYPE_RG 0x0
22 #define RSCTRL_RG 0x4
23 #define RSCFG_RG 0x8
24 #define RSISO_RG 0xc
25
26 #define RSCTRL_KEY_MASK 0x0000ffff
27 #define RSCTRL_RESET_MASK BIT(16)
28 #define RSCTRL_KEY 0x5a69
29
30 #define RSMUX_OMODE_MASK 0xe
31 #define RSMUX_OMODE_RESET_ON 0xa
32 #define RSMUX_OMODE_RESET_OFF 0x0
33 #define RSMUX_LOCK_MASK 0x1
34 #define RSMUX_LOCK_SET 0x1
35
36 #define RSCFG_RSTYPE_SOFT 0x300f
37 #define RSCFG_RSTYPE_HARD 0x0
38
39 #define WDT_MUX_NUMBER 0x4
40
41 static int rspll_offset;
42 static struct regmap *pllctrl_regs;
43
44 /**
45 * rsctrl_enable_rspll_write - enable access to RSCTRL, RSCFG
46 * To be able to access to RSCTRL, RSCFG registers
47 * we have to write a key before
48 */
rsctrl_enable_rspll_write(void)49 static inline int rsctrl_enable_rspll_write(void)
50 {
51 return regmap_update_bits(pllctrl_regs, rspll_offset + RSCTRL_RG,
52 RSCTRL_KEY_MASK, RSCTRL_KEY);
53 }
54
rsctrl_restart_handler(struct notifier_block * this,unsigned long mode,void * cmd)55 static int rsctrl_restart_handler(struct notifier_block *this,
56 unsigned long mode, void *cmd)
57 {
58 /* enable write access to RSTCTRL */
59 rsctrl_enable_rspll_write();
60
61 /* reset the SOC */
62 regmap_update_bits(pllctrl_regs, rspll_offset + RSCTRL_RG,
63 RSCTRL_RESET_MASK, 0);
64
65 return NOTIFY_DONE;
66 }
67
68 static struct notifier_block rsctrl_restart_nb = {
69 .notifier_call = rsctrl_restart_handler,
70 .priority = 128,
71 };
72
73 static const struct of_device_id rsctrl_of_match[] = {
74 {.compatible = "ti,keystone-reset", },
75 {},
76 };
77
rsctrl_probe(struct platform_device * pdev)78 static int rsctrl_probe(struct platform_device *pdev)
79 {
80 int i;
81 int ret;
82 u32 val;
83 unsigned int rg;
84 u32 rsmux_offset;
85 struct regmap *devctrl_regs;
86 struct device *dev = &pdev->dev;
87 struct device_node *np = dev->of_node;
88
89 if (!np)
90 return -ENODEV;
91
92 /* get regmaps */
93 pllctrl_regs = syscon_regmap_lookup_by_phandle(np, "ti,syscon-pll");
94 if (IS_ERR(pllctrl_regs))
95 return PTR_ERR(pllctrl_regs);
96
97 devctrl_regs = syscon_regmap_lookup_by_phandle(np, "ti,syscon-dev");
98 if (IS_ERR(devctrl_regs))
99 return PTR_ERR(devctrl_regs);
100
101 ret = of_property_read_u32_index(np, "ti,syscon-pll", 1, &rspll_offset);
102 if (ret) {
103 dev_err(dev, "couldn't read the reset pll offset!\n");
104 return -EINVAL;
105 }
106
107 ret = of_property_read_u32_index(np, "ti,syscon-dev", 1, &rsmux_offset);
108 if (ret) {
109 dev_err(dev, "couldn't read the rsmux offset!\n");
110 return -EINVAL;
111 }
112
113 /* set soft/hard reset */
114 val = of_property_read_bool(np, "ti,soft-reset");
115 val = val ? RSCFG_RSTYPE_SOFT : RSCFG_RSTYPE_HARD;
116
117 ret = rsctrl_enable_rspll_write();
118 if (ret)
119 return ret;
120
121 ret = regmap_write(pllctrl_regs, rspll_offset + RSCFG_RG, val);
122 if (ret)
123 return ret;
124
125 /* disable a reset isolation for all module clocks */
126 ret = regmap_write(pllctrl_regs, rspll_offset + RSISO_RG, 0);
127 if (ret)
128 return ret;
129
130 /* enable a reset for watchdogs from wdt-list */
131 for (i = 0; i < WDT_MUX_NUMBER; i++) {
132 ret = of_property_read_u32_index(np, "ti,wdt-list", i, &val);
133 if (ret == -EOVERFLOW && !i) {
134 dev_err(dev, "ti,wdt-list property has to contain at"
135 "least one entry\n");
136 return -EINVAL;
137 } else if (ret) {
138 break;
139 }
140
141 if (val >= WDT_MUX_NUMBER) {
142 dev_err(dev, "ti,wdt-list property can contain "
143 "only numbers < 4\n");
144 return -EINVAL;
145 }
146
147 rg = rsmux_offset + val * 4;
148
149 ret = regmap_update_bits(devctrl_regs, rg, RSMUX_OMODE_MASK,
150 RSMUX_OMODE_RESET_ON |
151 RSMUX_LOCK_SET);
152 if (ret)
153 return ret;
154 }
155
156 ret = register_restart_handler(&rsctrl_restart_nb);
157 if (ret)
158 dev_err(dev, "cannot register restart handler (err=%d)\n", ret);
159
160 return ret;
161 }
162
163 static struct platform_driver rsctrl_driver = {
164 .probe = rsctrl_probe,
165 .driver = {
166 .name = KBUILD_MODNAME,
167 .of_match_table = rsctrl_of_match,
168 },
169 };
170 module_platform_driver(rsctrl_driver);
171
172 MODULE_AUTHOR("Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>");
173 MODULE_DESCRIPTION("Texas Instruments keystone reset driver");
174 MODULE_LICENSE("GPL v2");
175 MODULE_ALIAS("platform:" KBUILD_MODNAME);
176
