1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * TI keystone reboot driver |
4 | * |
5 | * Copyright (C) 2014 Texas Instruments Incorporated. https://www.ti.com/ |
6 | * |
7 | * Author: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com> |
8 | */ |
9 | |
10 | #include <linux/io.h> |
11 | #include <linux/module.h> |
12 | #include <linux/notifier.h> |
13 | #include <linux/platform_device.h> |
14 | #include <linux/reboot.h> |
15 | #include <linux/regmap.h> |
16 | #include <linux/mfd/syscon.h> |
17 | #include <linux/of.h> |
18 | |
19 | #define RSTYPE_RG 0x0 |
20 | #define RSCTRL_RG 0x4 |
21 | #define RSCFG_RG 0x8 |
22 | #define RSISO_RG 0xc |
23 | |
24 | #define RSCTRL_KEY_MASK 0x0000ffff |
25 | #define RSCTRL_RESET_MASK BIT(16) |
26 | #define RSCTRL_KEY 0x5a69 |
27 | |
28 | #define RSMUX_OMODE_MASK 0xe |
29 | #define RSMUX_OMODE_RESET_ON 0xa |
30 | #define RSMUX_OMODE_RESET_OFF 0x0 |
31 | #define RSMUX_LOCK_MASK 0x1 |
32 | #define RSMUX_LOCK_SET 0x1 |
33 | |
34 | #define RSCFG_RSTYPE_SOFT 0x300f |
35 | #define RSCFG_RSTYPE_HARD 0x0 |
36 | |
37 | #define WDT_MUX_NUMBER 0x4 |
38 | |
39 | static int rspll_offset; |
40 | static struct regmap *pllctrl_regs; |
41 | |
42 | /** |
43 | * rsctrl_enable_rspll_write - enable access to RSCTRL, RSCFG |
44 | * To be able to access to RSCTRL, RSCFG registers |
45 | * we have to write a key before |
46 | */ |
47 | static inline int rsctrl_enable_rspll_write(void) |
48 | { |
49 | return regmap_update_bits(map: pllctrl_regs, reg: rspll_offset + RSCTRL_RG, |
50 | RSCTRL_KEY_MASK, RSCTRL_KEY); |
51 | } |
52 | |
53 | static int rsctrl_restart_handler(struct notifier_block *this, |
54 | unsigned long mode, void *cmd) |
55 | { |
56 | /* enable write access to RSTCTRL */ |
57 | rsctrl_enable_rspll_write(); |
58 | |
59 | /* reset the SOC */ |
60 | regmap_update_bits(map: pllctrl_regs, reg: rspll_offset + RSCTRL_RG, |
61 | RSCTRL_RESET_MASK, val: 0); |
62 | |
63 | return NOTIFY_DONE; |
64 | } |
65 | |
66 | static struct notifier_block rsctrl_restart_nb = { |
67 | .notifier_call = rsctrl_restart_handler, |
68 | .priority = 128, |
69 | }; |
70 | |
71 | static const struct of_device_id rsctrl_of_match[] = { |
72 | {.compatible = "ti,keystone-reset" , }, |
73 | {}, |
74 | }; |
75 | MODULE_DEVICE_TABLE(of, rsctrl_of_match); |
76 | |
77 | static int rsctrl_probe(struct platform_device *pdev) |
78 | { |
79 | int i; |
80 | int ret; |
81 | u32 val; |
82 | unsigned int rg; |
83 | u32 rsmux_offset; |
84 | struct regmap *devctrl_regs; |
85 | struct device *dev = &pdev->dev; |
86 | struct device_node *np = dev->of_node; |
87 | |
88 | if (!np) |
89 | return -ENODEV; |
90 | |
91 | /* get regmaps */ |
92 | pllctrl_regs = syscon_regmap_lookup_by_phandle(np, property: "ti,syscon-pll" ); |
93 | if (IS_ERR(ptr: pllctrl_regs)) |
94 | return PTR_ERR(ptr: pllctrl_regs); |
95 | |
96 | devctrl_regs = syscon_regmap_lookup_by_phandle(np, property: "ti,syscon-dev" ); |
97 | if (IS_ERR(ptr: devctrl_regs)) |
98 | return PTR_ERR(ptr: devctrl_regs); |
99 | |
100 | ret = of_property_read_u32_index(np, propname: "ti,syscon-pll" , index: 1, out_value: &rspll_offset); |
101 | if (ret) { |
102 | dev_err(dev, "couldn't read the reset pll offset!\n" ); |
103 | return -EINVAL; |
104 | } |
105 | |
106 | ret = of_property_read_u32_index(np, propname: "ti,syscon-dev" , index: 1, out_value: &rsmux_offset); |
107 | if (ret) { |
108 | dev_err(dev, "couldn't read the rsmux offset!\n" ); |
109 | return -EINVAL; |
110 | } |
111 | |
112 | /* set soft/hard reset */ |
113 | val = of_property_read_bool(np, propname: "ti,soft-reset" ); |
114 | val = val ? RSCFG_RSTYPE_SOFT : RSCFG_RSTYPE_HARD; |
115 | |
116 | ret = rsctrl_enable_rspll_write(); |
117 | if (ret) |
118 | return ret; |
119 | |
120 | ret = regmap_write(map: pllctrl_regs, reg: rspll_offset + RSCFG_RG, val); |
121 | if (ret) |
122 | return ret; |
123 | |
124 | /* disable a reset isolation for all module clocks */ |
125 | ret = regmap_write(map: pllctrl_regs, reg: rspll_offset + RSISO_RG, val: 0); |
126 | if (ret) |
127 | return ret; |
128 | |
129 | /* enable a reset for watchdogs from wdt-list */ |
130 | for (i = 0; i < WDT_MUX_NUMBER; i++) { |
131 | ret = of_property_read_u32_index(np, propname: "ti,wdt-list" , index: i, out_value: &val); |
132 | if (ret == -EOVERFLOW && !i) { |
133 | dev_err(dev, "ti,wdt-list property has to contain at" |
134 | "least one entry\n" ); |
135 | return -EINVAL; |
136 | } else if (ret) { |
137 | break; |
138 | } |
139 | |
140 | if (val >= WDT_MUX_NUMBER) { |
141 | dev_err(dev, "ti,wdt-list property can contain " |
142 | "only numbers < 4\n" ); |
143 | return -EINVAL; |
144 | } |
145 | |
146 | rg = rsmux_offset + val * 4; |
147 | |
148 | ret = regmap_update_bits(map: devctrl_regs, reg: rg, RSMUX_OMODE_MASK, |
149 | RSMUX_OMODE_RESET_ON | |
150 | RSMUX_LOCK_SET); |
151 | if (ret) |
152 | return ret; |
153 | } |
154 | |
155 | ret = register_restart_handler(&rsctrl_restart_nb); |
156 | if (ret) |
157 | dev_err(dev, "cannot register restart handler (err=%d)\n" , ret); |
158 | |
159 | return ret; |
160 | } |
161 | |
162 | static struct platform_driver rsctrl_driver = { |
163 | .probe = rsctrl_probe, |
164 | .driver = { |
165 | .name = KBUILD_MODNAME, |
166 | .of_match_table = rsctrl_of_match, |
167 | }, |
168 | }; |
169 | module_platform_driver(rsctrl_driver); |
170 | |
171 | MODULE_AUTHOR("Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>" ); |
172 | MODULE_DESCRIPTION("Texas Instruments keystone reset driver" ); |
173 | MODULE_ALIAS("platform:" KBUILD_MODNAME); |
174 | |