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