2 * Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
3 * JZ4740 Watchdog driver
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; either version 2 of the License, or (at your
8 * option) any later version.
10 * You should have received a copy of the GNU General Public License along
11 * with this program; if not, write to the Free Software Foundation, Inc.,
12 * 675 Mass Ave, Cambridge, MA 02139, USA.
16 #include <linux/module.h>
17 #include <linux/moduleparam.h>
18 #include <linux/types.h>
19 #include <linux/kernel.h>
21 #include <linux/miscdevice.h>
22 #include <linux/watchdog.h>
23 #include <linux/init.h>
24 #include <linux/bitops.h>
25 #include <linux/platform_device.h>
26 #include <linux/spinlock.h>
27 #include <linux/uaccess.h>
29 #include <linux/device.h>
30 #include <linux/clk.h>
31 #include <linux/slab.h>
33 #include <asm/mach-jz4740/timer.h>
35 #define JZ_REG_WDT_TIMER_DATA 0x0
36 #define JZ_REG_WDT_COUNTER_ENABLE 0x4
37 #define JZ_REG_WDT_TIMER_COUNTER 0x8
38 #define JZ_REG_WDT_TIMER_CONTROL 0xC
40 #define JZ_WDT_CLOCK_PCLK 0x1
41 #define JZ_WDT_CLOCK_RTC 0x2
42 #define JZ_WDT_CLOCK_EXT 0x4
45 #define WDT_OK_TO_CLOSE 1
47 #define JZ_WDT_CLOCK_DIV_SHIFT 3
49 #define JZ_WDT_CLOCK_DIV_1 (0 << JZ_WDT_CLOCK_DIV_SHIFT)
50 #define JZ_WDT_CLOCK_DIV_4 (1 << JZ_WDT_CLOCK_DIV_SHIFT)
51 #define JZ_WDT_CLOCK_DIV_16 (2 << JZ_WDT_CLOCK_DIV_SHIFT)
52 #define JZ_WDT_CLOCK_DIV_64 (3 << JZ_WDT_CLOCK_DIV_SHIFT)
53 #define JZ_WDT_CLOCK_DIV_256 (4 << JZ_WDT_CLOCK_DIV_SHIFT)
54 #define JZ_WDT_CLOCK_DIV_1024 (5 << JZ_WDT_CLOCK_DIV_SHIFT)
56 #define DEFAULT_HEARTBEAT 5
57 #define MAX_HEARTBEAT 2048
66 static int heartbeat
= DEFAULT_HEARTBEAT
;
69 static void jz4740_wdt_service(void)
71 writew(0x0, jz4740_wdt
.base
+ JZ_REG_WDT_TIMER_COUNTER
);
74 static void jz4740_wdt_set_heartbeat(int new_heartbeat
)
76 unsigned int rtc_clk_rate
;
77 unsigned int timeout_value
;
78 unsigned short clock_div
= JZ_WDT_CLOCK_DIV_1
;
80 heartbeat
= new_heartbeat
;
82 rtc_clk_rate
= clk_get_rate(jz4740_wdt
.rtc_clk
);
84 timeout_value
= rtc_clk_rate
* heartbeat
;
85 while (timeout_value
> 0xffff) {
86 if (clock_div
== JZ_WDT_CLOCK_DIV_1024
) {
87 /* Requested timeout too high;
88 * use highest possible value. */
89 timeout_value
= 0xffff;
93 clock_div
+= (1 << JZ_WDT_CLOCK_DIV_SHIFT
);
96 writeb(0x0, jz4740_wdt
.base
+ JZ_REG_WDT_COUNTER_ENABLE
);
97 writew(clock_div
, jz4740_wdt
.base
+ JZ_REG_WDT_TIMER_CONTROL
);
99 writew((u16
)timeout_value
, jz4740_wdt
.base
+ JZ_REG_WDT_TIMER_DATA
);
100 writew(0x0, jz4740_wdt
.base
+ JZ_REG_WDT_TIMER_COUNTER
);
101 writew(clock_div
| JZ_WDT_CLOCK_RTC
,
102 jz4740_wdt
.base
+ JZ_REG_WDT_TIMER_CONTROL
);
104 writeb(0x1, jz4740_wdt
.base
+ JZ_REG_WDT_COUNTER_ENABLE
);
107 static void jz4740_wdt_enable(void)
109 jz4740_timer_enable_watchdog();
110 jz4740_wdt_set_heartbeat(heartbeat
);
113 static void jz4740_wdt_disable(void)
115 jz4740_timer_disable_watchdog();
116 writeb(0x0, jz4740_wdt
.base
+ JZ_REG_WDT_COUNTER_ENABLE
);
119 static int jz4740_wdt_open(struct inode
*inode
, struct file
*file
)
121 if (test_and_set_bit(WDT_IN_USE
, &jz4740_wdt
.status
))
126 return nonseekable_open(inode
, file
);
129 static ssize_t
jz4740_wdt_write(struct file
*file
, const char *data
,
130 size_t len
, loff_t
*ppos
)
133 if (data
[len
-1] == 'V')
134 set_bit(WDT_OK_TO_CLOSE
, &jz4740_wdt
.status
);
136 clear_bit(WDT_OK_TO_CLOSE
, &jz4740_wdt
.status
);
138 jz4740_wdt_service();
144 static const struct watchdog_info ident
= {
145 .options
= WDIOF_KEEPALIVEPING
,
146 .identity
= "jz4740 Watchdog",
149 static long jz4740_wdt_ioctl(struct file
*file
,
150 unsigned int cmd
, unsigned long arg
)
153 int heartbeat_seconds
;
156 case WDIOC_GETSUPPORT
:
157 ret
= copy_to_user((struct watchdog_info
*)arg
, &ident
,
158 sizeof(ident
)) ? -EFAULT
: 0;
161 case WDIOC_GETSTATUS
:
162 case WDIOC_GETBOOTSTATUS
:
163 ret
= put_user(0, (int *)arg
);
166 case WDIOC_KEEPALIVE
:
167 jz4740_wdt_service();
170 case WDIOC_SETTIMEOUT
:
171 if (get_user(heartbeat_seconds
, (int __user
*)arg
))
174 jz4740_wdt_set_heartbeat(heartbeat_seconds
);
177 case WDIOC_GETTIMEOUT
:
178 return put_user(heartbeat
, (int *)arg
);
187 static int jz4740_wdt_release(struct inode
*inode
, struct file
*file
)
189 jz4740_wdt_service();
191 if (test_and_clear_bit(WDT_OK_TO_CLOSE
, &jz4740_wdt
.status
))
192 jz4740_wdt_disable();
194 clear_bit(WDT_IN_USE
, &jz4740_wdt
.status
);
198 static const struct file_operations jz4740_wdt_fops
= {
199 .owner
= THIS_MODULE
,
201 .write
= jz4740_wdt_write
,
202 .unlocked_ioctl
= jz4740_wdt_ioctl
,
203 .open
= jz4740_wdt_open
,
204 .release
= jz4740_wdt_release
,
207 static struct miscdevice jz4740_wdt_miscdev
= {
208 .minor
= WATCHDOG_MINOR
,
210 .fops
= &jz4740_wdt_fops
,
213 static int __devinit
jz4740_wdt_probe(struct platform_device
*pdev
)
216 struct resource
*res
;
217 struct device
*dev
= &pdev
->dev
;
219 res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
221 dev_err(dev
, "failed to get memory region resource\n");
225 size
= resource_size(res
);
226 jz4740_wdt
.mem
= request_mem_region(res
->start
, size
, pdev
->name
);
227 if (jz4740_wdt
.mem
== NULL
) {
228 dev_err(dev
, "failed to get memory region\n");
232 jz4740_wdt
.base
= ioremap_nocache(res
->start
, size
);
233 if (jz4740_wdt
.base
== NULL
) {
234 dev_err(dev
, "failed to map memory region\n");
236 goto err_release_region
;
239 jz4740_wdt
.rtc_clk
= clk_get(NULL
, "rtc");
240 if (IS_ERR(jz4740_wdt
.rtc_clk
)) {
241 dev_err(dev
, "cannot find RTC clock\n");
242 ret
= PTR_ERR(jz4740_wdt
.rtc_clk
);
246 ret
= misc_register(&jz4740_wdt_miscdev
);
248 dev_err(dev
, "cannot register misc device\n");
249 goto err_disable_clk
;
255 clk_put(jz4740_wdt
.rtc_clk
);
257 iounmap(jz4740_wdt
.base
);
259 release_mem_region(jz4740_wdt
.mem
->start
,
260 resource_size(jz4740_wdt
.mem
));
265 static int __devexit
jz4740_wdt_remove(struct platform_device
*pdev
)
267 jz4740_wdt_disable();
268 misc_deregister(&jz4740_wdt_miscdev
);
269 clk_put(jz4740_wdt
.rtc_clk
);
271 iounmap(jz4740_wdt
.base
);
272 jz4740_wdt
.base
= NULL
;
274 release_mem_region(jz4740_wdt
.mem
->start
,
275 resource_size(jz4740_wdt
.mem
));
276 jz4740_wdt
.mem
= NULL
;
282 static struct platform_driver jz4740_wdt_driver
= {
283 .probe
= jz4740_wdt_probe
,
284 .remove
= __devexit_p(jz4740_wdt_remove
),
286 .name
= "jz4740-wdt",
287 .owner
= THIS_MODULE
,
292 static int __init
jz4740_wdt_init(void)
294 return platform_driver_register(&jz4740_wdt_driver
);
296 module_init(jz4740_wdt_init
);
298 static void __exit
jz4740_wdt_exit(void)
300 platform_driver_unregister(&jz4740_wdt_driver
);
302 module_exit(jz4740_wdt_exit
);
304 MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
305 MODULE_DESCRIPTION("jz4740 Watchdog Driver");
307 module_param(heartbeat
, int, 0);
308 MODULE_PARM_DESC(heartbeat
,
309 "Watchdog heartbeat period in seconds from 1 to "
310 __MODULE_STRING(MAX_HEARTBEAT
) ", default "
311 __MODULE_STRING(DEFAULT_HEARTBEAT
));
313 MODULE_LICENSE("GPL");
314 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR
);
315 MODULE_ALIAS("platform:jz4740-wdt");