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
|
/*
* Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
* JZ4740 Watchdog driver
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/clk.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <asm/mach-jz4740/timer.h>
#define JZ_REG_WDT_TIMER_DATA 0x0
#define JZ_REG_WDT_COUNTER_ENABLE 0x4
#define JZ_REG_WDT_TIMER_COUNTER 0x8
#define JZ_REG_WDT_TIMER_CONTROL 0xC
#define JZ_WDT_CLOCK_PCLK 0x1
#define JZ_WDT_CLOCK_RTC 0x2
#define JZ_WDT_CLOCK_EXT 0x4
#define JZ_WDT_CLOCK_DIV_SHIFT 3
#define JZ_WDT_CLOCK_DIV_1 (0 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_4 (1 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_16 (2 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_64 (3 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_256 (4 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_1024 (5 << JZ_WDT_CLOCK_DIV_SHIFT)
#define DEFAULT_HEARTBEAT 5
#define MAX_HEARTBEAT 2048
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 unsigned int heartbeat = DEFAULT_HEARTBEAT;
module_param(heartbeat, uint, 0);
MODULE_PARM_DESC(heartbeat,
"Watchdog heartbeat period in seconds from 1 to "
__MODULE_STRING(MAX_HEARTBEAT) ", default "
__MODULE_STRING(DEFAULT_HEARTBEAT));
struct jz4740_wdt_drvdata {
struct watchdog_device wdt;
void __iomem *base;
struct clk *rtc_clk;
};
static int jz4740_wdt_ping(struct watchdog_device *wdt_dev)
{
struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
writew(0x0, drvdata->base + JZ_REG_WDT_TIMER_COUNTER);
return 0;
}
static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int new_timeout)
{
struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
unsigned int rtc_clk_rate;
unsigned int timeout_value;
unsigned short clock_div = JZ_WDT_CLOCK_DIV_1;
rtc_clk_rate = clk_get_rate(drvdata->rtc_clk);
timeout_value = rtc_clk_rate * new_timeout;
while (timeout_value > 0xffff) {
if (clock_div == JZ_WDT_CLOCK_DIV_1024) {
/* Requested timeout too high;
* use highest possible value. */
timeout_value = 0xffff;
break;
}
timeout_value >>= 2;
clock_div += (1 << JZ_WDT_CLOCK_DIV_SHIFT);
}
writeb(0x0, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
writew(clock_div, drvdata->base + JZ_REG_WDT_TIMER_CONTROL);
writew((u16)timeout_value, drvdata->base + JZ_REG_WDT_TIMER_DATA);
writew(0x0, drvdata->base + JZ_REG_WDT_TIMER_COUNTER);
writew(clock_div | JZ_WDT_CLOCK_RTC,
drvdata->base + JZ_REG_WDT_TIMER_CONTROL);
writeb(0x1, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
wdt_dev->timeout = new_timeout;
return 0;
}
static int jz4740_wdt_start(struct watchdog_device *wdt_dev)
{
jz4740_timer_enable_watchdog();
jz4740_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
return 0;
}
static int jz4740_wdt_stop(struct watchdog_device *wdt_dev)
{
struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
jz4740_timer_disable_watchdog();
writeb(0x0, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
return 0;
}
static const struct watchdog_info jz4740_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.identity = "jz4740 Watchdog",
};
static const struct watchdog_ops jz4740_wdt_ops = {
.owner = THIS_MODULE,
.start = jz4740_wdt_start,
.stop = jz4740_wdt_stop,
.ping = jz4740_wdt_ping,
.set_timeout = jz4740_wdt_set_timeout,
};
static int jz4740_wdt_probe(struct platform_device *pdev)
{
struct jz4740_wdt_drvdata *drvdata;
struct watchdog_device *jz4740_wdt;
struct resource *res;
int ret;
drvdata = devm_kzalloc(&pdev->dev, sizeof(struct jz4740_wdt_drvdata),
GFP_KERNEL);
if (!drvdata) {
dev_err(&pdev->dev, "Unable to alloacate watchdog device\n");
return -ENOMEM;
}
if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
heartbeat = DEFAULT_HEARTBEAT;
jz4740_wdt = &drvdata->wdt;
jz4740_wdt->info = &jz4740_wdt_info;
jz4740_wdt->ops = &jz4740_wdt_ops;
jz4740_wdt->timeout = heartbeat;
jz4740_wdt->min_timeout = 1;
jz4740_wdt->max_timeout = MAX_HEARTBEAT;
watchdog_set_nowayout(jz4740_wdt, nowayout);
watchdog_set_drvdata(jz4740_wdt, drvdata);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
drvdata->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(drvdata->base)) {
ret = PTR_ERR(drvdata->base);
goto err_out;
}
drvdata->rtc_clk = clk_get(NULL, "rtc");
if (IS_ERR(drvdata->rtc_clk)) {
dev_err(&pdev->dev, "cannot find RTC clock\n");
ret = PTR_ERR(drvdata->rtc_clk);
goto err_out;
}
ret = watchdog_register_device(&drvdata->wdt);
if (ret < 0)
goto err_disable_clk;
platform_set_drvdata(pdev, drvdata);
return 0;
err_disable_clk:
clk_put(drvdata->rtc_clk);
err_out:
return ret;
}
static int jz4740_wdt_remove(struct platform_device *pdev)
{
struct jz4740_wdt_drvdata *drvdata = platform_get_drvdata(pdev);
jz4740_wdt_stop(&drvdata->wdt);
watchdog_unregister_device(&drvdata->wdt);
clk_put(drvdata->rtc_clk);
return 0;
}
static struct platform_driver jz4740_wdt_driver = {
.probe = jz4740_wdt_probe,
.remove = jz4740_wdt_remove,
.driver = {
.name = "jz4740-wdt",
.owner = THIS_MODULE,
},
};
module_platform_driver(jz4740_wdt_driver);
MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
MODULE_DESCRIPTION("jz4740 Watchdog Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS("platform:jz4740-wdt");
|
