1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* sl28cpld watchdog driver
*
* Copyright 2020 Kontron Europe GmbH
*/
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/watchdog.h>
/*
* Watchdog timer block registers.
*/
#define WDT_CTRL 0x00
#define WDT_CTRL_EN BIT(0)
#define WDT_CTRL_LOCK BIT(2)
#define WDT_CTRL_ASSERT_SYS_RESET BIT(6)
#define WDT_CTRL_ASSERT_WDT_TIMEOUT BIT(7)
#define WDT_TIMEOUT 0x01
#define WDT_KICK 0x02
#define WDT_KICK_VALUE 0x6b
#define WDT_COUNT 0x03
#define WDT_DEFAULT_TIMEOUT 10
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
static int timeout;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Initial watchdog timeout in seconds");
struct sl28cpld_wdt {
struct watchdog_device wdd;
struct regmap *regmap;
u32 offset;
bool assert_wdt_timeout;
};
static int sl28cpld_wdt_ping(struct watchdog_device *wdd)
{
struct sl28cpld_wdt *wdt = watchdog_get_drvdata(wdd);
return regmap_write(wdt->regmap, wdt->offset + WDT_KICK,
WDT_KICK_VALUE);
}
static int sl28cpld_wdt_start(struct watchdog_device *wdd)
{
struct sl28cpld_wdt *wdt = watchdog_get_drvdata(wdd);
unsigned int val;
val = WDT_CTRL_EN | WDT_CTRL_ASSERT_SYS_RESET;
if (wdt->assert_wdt_timeout)
val |= WDT_CTRL_ASSERT_WDT_TIMEOUT;
if (nowayout)
val |= WDT_CTRL_LOCK;
return regmap_update_bits(wdt->regmap, wdt->offset + WDT_CTRL,
val, val);
}
static int sl28cpld_wdt_stop(struct watchdog_device *wdd)
{
struct sl28cpld_wdt *wdt = watchdog_get_drvdata(wdd);
return regmap_update_bits(wdt->regmap, wdt->offset + WDT_CTRL,
WDT_CTRL_EN, 0);
}
static unsigned int sl28cpld_wdt_get_timeleft(struct watchdog_device *wdd)
{
struct sl28cpld_wdt *wdt = watchdog_get_drvdata(wdd);
unsigned int val;
int ret;
ret = regmap_read(wdt->regmap, wdt->offset + WDT_COUNT, &val);
if (ret)
return 0;
return val;
}
static int sl28cpld_wdt_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
struct sl28cpld_wdt *wdt = watchdog_get_drvdata(wdd);
int ret;
ret = regmap_write(wdt->regmap, wdt->offset + WDT_TIMEOUT, timeout);
if (ret)
return ret;
wdd->timeout = timeout;
return 0;
}
static const struct watchdog_info sl28cpld_wdt_info = {
.options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
.identity = "sl28cpld watchdog",
};
static const struct watchdog_ops sl28cpld_wdt_ops = {
.owner = THIS_MODULE,
.start = sl28cpld_wdt_start,
.stop = sl28cpld_wdt_stop,
.ping = sl28cpld_wdt_ping,
.set_timeout = sl28cpld_wdt_set_timeout,
.get_timeleft = sl28cpld_wdt_get_timeleft,
};
static int sl28cpld_wdt_probe(struct platform_device *pdev)
{
struct watchdog_device *wdd;
struct sl28cpld_wdt *wdt;
unsigned int status;
unsigned int val;
int ret;
if (!pdev->dev.parent)
return -ENODEV;
wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
wdt->regmap = dev_get_regmap(pdev->dev.parent, NULL);
if (!wdt->regmap)
return -ENODEV;
ret = device_property_read_u32(&pdev->dev, "reg", &wdt->offset);
if (ret)
return -EINVAL;
wdt->assert_wdt_timeout = device_property_read_bool(&pdev->dev,
"kontron,assert-wdt-timeout-pin");
/* initialize struct watchdog_device */
wdd = &wdt->wdd;
wdd->parent = &pdev->dev;
wdd->info = &sl28cpld_wdt_info;
wdd->ops = &sl28cpld_wdt_ops;
wdd->min_timeout = 1;
wdd->max_timeout = 255;
watchdog_set_drvdata(wdd, wdt);
watchdog_stop_on_reboot(wdd);
/*
* Read the status early, in case of an error, we haven't modified the
* hardware.
*/
ret = regmap_read(wdt->regmap, wdt->offset + WDT_CTRL, &status);
if (ret)
return ret;
/*
* Initial timeout value, may be overwritten by device tree or module
* parameter in watchdog_init_timeout().
*
* Reading a zero here means that either the hardware has a default
* value of zero (which is very unlikely and definitely a hardware
* bug) or the bootloader set it to zero. In any case, we handle
* this case gracefully and set out own timeout.
*/
ret = regmap_read(wdt->regmap, wdt->offset + WDT_TIMEOUT, &val);
if (ret)
return ret;
if (val)
wdd->timeout = val;
else
wdd->timeout = WDT_DEFAULT_TIMEOUT;
watchdog_init_timeout(wdd, timeout, &pdev->dev);
sl28cpld_wdt_set_timeout(wdd, wdd->timeout);
/* if the watchdog is locked, we set nowayout */
if (status & WDT_CTRL_LOCK)
nowayout = true;
watchdog_set_nowayout(wdd, nowayout);
/*
* If watchdog is already running, keep it enabled, but make
* sure its mode is set correctly.
*/
if (status & WDT_CTRL_EN) {
sl28cpld_wdt_start(wdd);
set_bit(WDOG_HW_RUNNING, &wdd->status);
}
ret = devm_watchdog_register_device(&pdev->dev, wdd);
if (ret < 0)
return ret;
dev_info(&pdev->dev, "initial timeout %d sec%s\n",
wdd->timeout, nowayout ? ", nowayout" : "");
return 0;
}
static const struct of_device_id sl28cpld_wdt_of_match[] = {
{ .compatible = "kontron,sl28cpld-wdt" },
{}
};
MODULE_DEVICE_TABLE(of, sl28cpld_wdt_of_match);
static struct platform_driver sl28cpld_wdt_driver = {
.probe = sl28cpld_wdt_probe,
.driver = {
.name = "sl28cpld-wdt",
.of_match_table = sl28cpld_wdt_of_match,
},
};
module_platform_driver(sl28cpld_wdt_driver);
MODULE_DESCRIPTION("sl28cpld Watchdog Driver");
MODULE_AUTHOR("Michael Walle <michael@walle.cc>");
MODULE_LICENSE("GPL");
|
