2 * Watchdog driver for Kendin/Micrel KS8695.
4 * (C) 2007 Andrew Victor
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/bitops.h>
14 #include <linux/errno.h>
16 #include <linux/init.h>
17 #include <linux/kernel.h>
18 #include <linux/miscdevice.h>
19 #include <linux/module.h>
20 #include <linux/moduleparam.h>
21 #include <linux/platform_device.h>
22 #include <linux/types.h>
23 #include <linux/watchdog.h>
25 #include <linux/uaccess.h>
26 #include <mach/hardware.h>
28 #define KS8695_TMR_OFFSET (0xF0000 + 0xE400)
29 #define KS8695_TMR_VA (KS8695_IO_VA + KS8695_TMR_OFFSET)
34 #define KS8695_TMCON (0x00) /* Timer Control Register */
35 #define KS8695_T0TC (0x08) /* Timer 0 Timeout Count Register */
36 #define TMCON_T0EN (1 << 0) /* Timer 0 Enable */
38 /* Timer0 Timeout Counter Register */
39 #define T0TC_WATCHDOG (0xff) /* Enable watchdog mode */
41 #define WDT_DEFAULT_TIME 5 /* seconds */
42 #define WDT_MAX_TIME 171 /* seconds */
44 static int wdt_time
= WDT_DEFAULT_TIME
;
45 static bool nowayout
= WATCHDOG_NOWAYOUT
;
47 module_param(wdt_time
, int, 0);
48 MODULE_PARM_DESC(wdt_time
, "Watchdog time in seconds. (default="
49 __MODULE_STRING(WDT_DEFAULT_TIME
) ")");
51 #ifdef CONFIG_WATCHDOG_NOWAYOUT
52 module_param(nowayout
, bool, 0);
53 MODULE_PARM_DESC(nowayout
, "Watchdog cannot be stopped once started (default="
54 __MODULE_STRING(WATCHDOG_NOWAYOUT
) ")");
58 static unsigned long ks8695wdt_busy
;
59 static DEFINE_SPINLOCK(ks8695_lock
);
61 /* ......................................................................... */
64 * Disable the watchdog.
66 static inline void ks8695_wdt_stop(void)
70 spin_lock(&ks8695_lock
);
72 tmcon
= __raw_readl(KS8695_TMR_VA
+ KS8695_TMCON
);
73 __raw_writel(tmcon
& ~TMCON_T0EN
, KS8695_TMR_VA
+ KS8695_TMCON
);
74 spin_unlock(&ks8695_lock
);
78 * Enable and reset the watchdog.
80 static inline void ks8695_wdt_start(void)
83 unsigned long tval
= wdt_time
* KS8695_CLOCK_RATE
;
85 spin_lock(&ks8695_lock
);
87 tmcon
= __raw_readl(KS8695_TMR_VA
+ KS8695_TMCON
);
88 __raw_writel(tmcon
& ~TMCON_T0EN
, KS8695_TMR_VA
+ KS8695_TMCON
);
91 __raw_writel(tval
| T0TC_WATCHDOG
, KS8695_TMR_VA
+ KS8695_T0TC
);
93 /* re-enable timer0 */
94 tmcon
= __raw_readl(KS8695_TMR_VA
+ KS8695_TMCON
);
95 __raw_writel(tmcon
| TMCON_T0EN
, KS8695_TMR_VA
+ KS8695_TMCON
);
96 spin_unlock(&ks8695_lock
);
100 * Reload the watchdog timer. (ie, pat the watchdog)
102 static inline void ks8695_wdt_reload(void)
106 spin_lock(&ks8695_lock
);
107 /* disable, then re-enable timer0 */
108 tmcon
= __raw_readl(KS8695_TMR_VA
+ KS8695_TMCON
);
109 __raw_writel(tmcon
& ~TMCON_T0EN
, KS8695_TMR_VA
+ KS8695_TMCON
);
110 __raw_writel(tmcon
| TMCON_T0EN
, KS8695_TMR_VA
+ KS8695_TMCON
);
111 spin_unlock(&ks8695_lock
);
115 * Change the watchdog time interval.
117 static int ks8695_wdt_settimeout(int new_time
)
120 * All counting occurs at KS8695_CLOCK_RATE / 128 = 0.256 Hz
122 * Since WDV is a 16-bit counter, the maximum period is
123 * 65536 / 0.256 = 256 seconds.
125 if ((new_time
<= 0) || (new_time
> WDT_MAX_TIME
))
128 /* Set new watchdog time. It will be used when
129 ks8695_wdt_start() is called. */
134 /* ......................................................................... */
137 * Watchdog device is opened, and watchdog starts running.
139 static int ks8695_wdt_open(struct inode
*inode
, struct file
*file
)
141 if (test_and_set_bit(0, &ks8695wdt_busy
))
145 return nonseekable_open(inode
, file
);
149 * Close the watchdog device.
150 * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
153 static int ks8695_wdt_close(struct inode
*inode
, struct file
*file
)
155 /* Disable the watchdog when file is closed */
158 clear_bit(0, &ks8695wdt_busy
);
162 static const struct watchdog_info ks8695_wdt_info
= {
163 .identity
= "ks8695 watchdog",
164 .options
= WDIOF_SETTIMEOUT
| WDIOF_KEEPALIVEPING
,
168 * Handle commands from user-space.
170 static long ks8695_wdt_ioctl(struct file
*file
, unsigned int cmd
,
173 void __user
*argp
= (void __user
*)arg
;
174 int __user
*p
= argp
;
178 case WDIOC_GETSUPPORT
:
179 return copy_to_user(argp
, &ks8695_wdt_info
,
180 sizeof(ks8695_wdt_info
)) ? -EFAULT
: 0;
181 case WDIOC_GETSTATUS
:
182 case WDIOC_GETBOOTSTATUS
:
183 return put_user(0, p
);
184 case WDIOC_SETOPTIONS
:
185 if (get_user(new_value
, p
))
187 if (new_value
& WDIOS_DISABLECARD
)
189 if (new_value
& WDIOS_ENABLECARD
)
192 case WDIOC_KEEPALIVE
:
193 ks8695_wdt_reload(); /* pat the watchdog */
195 case WDIOC_SETTIMEOUT
:
196 if (get_user(new_value
, p
))
198 if (ks8695_wdt_settimeout(new_value
))
200 /* Enable new time value */
202 /* Return current value */
203 return put_user(wdt_time
, p
);
204 case WDIOC_GETTIMEOUT
:
205 return put_user(wdt_time
, p
);
212 * Pat the watchdog whenever device is written to.
214 static ssize_t
ks8695_wdt_write(struct file
*file
, const char *data
,
215 size_t len
, loff_t
*ppos
)
217 ks8695_wdt_reload(); /* pat the watchdog */
221 /* ......................................................................... */
223 static const struct file_operations ks8695wdt_fops
= {
224 .owner
= THIS_MODULE
,
226 .unlocked_ioctl
= ks8695_wdt_ioctl
,
227 .open
= ks8695_wdt_open
,
228 .release
= ks8695_wdt_close
,
229 .write
= ks8695_wdt_write
,
232 static struct miscdevice ks8695wdt_miscdev
= {
233 .minor
= WATCHDOG_MINOR
,
235 .fops
= &ks8695wdt_fops
,
238 static int ks8695wdt_probe(struct platform_device
*pdev
)
242 if (ks8695wdt_miscdev
.parent
)
244 ks8695wdt_miscdev
.parent
= &pdev
->dev
;
246 res
= misc_register(&ks8695wdt_miscdev
);
250 pr_info("KS8695 Watchdog Timer enabled (%d seconds%s)\n",
251 wdt_time
, nowayout
? ", nowayout" : "");
255 static int ks8695wdt_remove(struct platform_device
*pdev
)
257 misc_deregister(&ks8695wdt_miscdev
);
258 ks8695wdt_miscdev
.parent
= NULL
;
263 static void ks8695wdt_shutdown(struct platform_device
*pdev
)
270 static int ks8695wdt_suspend(struct platform_device
*pdev
, pm_message_t message
)
276 static int ks8695wdt_resume(struct platform_device
*pdev
)
284 #define ks8695wdt_suspend NULL
285 #define ks8695wdt_resume NULL
288 static struct platform_driver ks8695wdt_driver
= {
289 .probe
= ks8695wdt_probe
,
290 .remove
= ks8695wdt_remove
,
291 .shutdown
= ks8695wdt_shutdown
,
292 .suspend
= ks8695wdt_suspend
,
293 .resume
= ks8695wdt_resume
,
295 .name
= "ks8695_wdt",
299 static int __init
ks8695_wdt_init(void)
301 /* Check that the heartbeat value is within range;
302 if not reset to the default */
303 if (ks8695_wdt_settimeout(wdt_time
)) {
304 ks8695_wdt_settimeout(WDT_DEFAULT_TIME
);
305 pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i"
306 ", using %d\n", wdt_time
, WDT_MAX_TIME
);
308 return platform_driver_register(&ks8695wdt_driver
);
311 static void __exit
ks8695_wdt_exit(void)
313 platform_driver_unregister(&ks8695wdt_driver
);
316 module_init(ks8695_wdt_init
);
317 module_exit(ks8695_wdt_exit
);
319 MODULE_AUTHOR("Andrew Victor");
320 MODULE_DESCRIPTION("Watchdog driver for KS8695");
321 MODULE_LICENSE("GPL");
322 MODULE_ALIAS("platform:ks8695_wdt");