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Andrew Victorccb8f432007-05-14 14:45:25 +02001/*
2 * Watchdog driver for Kendin/Micrel KS8695.
3 *
4 * (C) 2007 Andrew Victor
5 *
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.
9 */
10
Jiri Slaby1977f032007-10-18 23:40:25 -070011#include <linux/bitops.h>
Andrew Victorccb8f432007-05-14 14:45:25 +020012#include <linux/errno.h>
13#include <linux/fs.h>
14#include <linux/init.h>
15#include <linux/kernel.h>
16#include <linux/miscdevice.h>
17#include <linux/module.h>
18#include <linux/moduleparam.h>
19#include <linux/platform_device.h>
20#include <linux/types.h>
21#include <linux/watchdog.h>
Andrew Victorccb8f432007-05-14 14:45:25 +020022#include <asm/io.h>
23#include <asm/uaccess.h>
Russell Kinga09e64f2008-08-05 16:14:15 +010024#include <mach/regs-timer.h>
Andrew Victorccb8f432007-05-14 14:45:25 +020025
26
27#define WDT_DEFAULT_TIME 5 /* seconds */
28#define WDT_MAX_TIME 171 /* seconds */
29
30static int wdt_time = WDT_DEFAULT_TIME;
31static int nowayout = WATCHDOG_NOWAYOUT;
32
33module_param(wdt_time, int, 0);
34MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="__MODULE_STRING(WDT_DEFAULT_TIME) ")");
35
36#ifdef CONFIG_WATCHDOG_NOWAYOUT
37module_param(nowayout, int, 0);
38MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
39#endif
40
41
42static unsigned long ks8695wdt_busy;
43
44/* ......................................................................... */
45
46/*
47 * Disable the watchdog.
48 */
49static void inline ks8695_wdt_stop(void)
50{
51 unsigned long tmcon;
52
53 /* disable timer0 */
54 tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
55 __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
56}
57
58/*
59 * Enable and reset the watchdog.
60 */
61static void inline ks8695_wdt_start(void)
62{
63 unsigned long tmcon;
64 unsigned long tval = wdt_time * CLOCK_TICK_RATE;
65
66 /* disable timer0 */
67 tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
68 __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
69
70 /* program timer0 */
71 __raw_writel(tval | T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC);
72
73 /* re-enable timer0 */
74 tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
75 __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
76}
77
78/*
79 * Reload the watchdog timer. (ie, pat the watchdog)
80 */
81static void inline ks8695_wdt_reload(void)
82{
83 unsigned long tmcon;
84
85 /* disable, then re-enable timer0 */
86 tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
87 __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
88 __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
89}
90
91/*
92 * Change the watchdog time interval.
93 */
94static int ks8695_wdt_settimeout(int new_time)
95{
96 /*
97 * All counting occurs at SLOW_CLOCK / 128 = 0.256 Hz
98 *
99 * Since WDV is a 16-bit counter, the maximum period is
100 * 65536 / 0.256 = 256 seconds.
101 */
102 if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
103 return -EINVAL;
104
105 /* Set new watchdog time. It will be used when ks8695_wdt_start() is called. */
106 wdt_time = new_time;
107 return 0;
108}
109
110/* ......................................................................... */
111
112/*
113 * Watchdog device is opened, and watchdog starts running.
114 */
115static int ks8695_wdt_open(struct inode *inode, struct file *file)
116{
117 if (test_and_set_bit(0, &ks8695wdt_busy))
118 return -EBUSY;
119
120 ks8695_wdt_start();
121 return nonseekable_open(inode, file);
122}
123
124/*
125 * Close the watchdog device.
126 * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
127 * disabled.
128 */
129static int ks8695_wdt_close(struct inode *inode, struct file *file)
130{
131 if (!nowayout)
132 ks8695_wdt_stop(); /* Disable the watchdog when file is closed */
133
134 clear_bit(0, &ks8695wdt_busy);
135 return 0;
136}
137
138static struct watchdog_info ks8695_wdt_info = {
139 .identity = "ks8695 watchdog",
140 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
141};
142
143/*
144 * Handle commands from user-space.
145 */
146static int ks8695_wdt_ioctl(struct inode *inode, struct file *file,
147 unsigned int cmd, unsigned long arg)
148{
149 void __user *argp = (void __user *)arg;
150 int __user *p = argp;
151 int new_value;
152
153 switch(cmd) {
154 case WDIOC_KEEPALIVE:
155 ks8695_wdt_reload(); /* pat the watchdog */
156 return 0;
157
158 case WDIOC_GETSUPPORT:
159 return copy_to_user(argp, &ks8695_wdt_info, sizeof(ks8695_wdt_info)) ? -EFAULT : 0;
160
161 case WDIOC_SETTIMEOUT:
162 if (get_user(new_value, p))
163 return -EFAULT;
164
165 if (ks8695_wdt_settimeout(new_value))
166 return -EINVAL;
167
168 /* Enable new time value */
169 ks8695_wdt_start();
170
171 /* Return current value */
172 return put_user(wdt_time, p);
173
174 case WDIOC_GETTIMEOUT:
175 return put_user(wdt_time, p);
176
177 case WDIOC_GETSTATUS:
178 case WDIOC_GETBOOTSTATUS:
179 return put_user(0, p);
180
181 case WDIOC_SETOPTIONS:
182 if (get_user(new_value, p))
183 return -EFAULT;
184
185 if (new_value & WDIOS_DISABLECARD)
186 ks8695_wdt_stop();
187 if (new_value & WDIOS_ENABLECARD)
188 ks8695_wdt_start();
189 return 0;
190
191 default:
192 return -ENOTTY;
193 }
194}
195
196/*
197 * Pat the watchdog whenever device is written to.
198 */
199static ssize_t ks8695_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
200{
201 ks8695_wdt_reload(); /* pat the watchdog */
202 return len;
203}
204
205/* ......................................................................... */
206
207static const struct file_operations ks8695wdt_fops = {
208 .owner = THIS_MODULE,
209 .llseek = no_llseek,
210 .ioctl = ks8695_wdt_ioctl,
211 .open = ks8695_wdt_open,
212 .release = ks8695_wdt_close,
213 .write = ks8695_wdt_write,
214};
215
216static struct miscdevice ks8695wdt_miscdev = {
217 .minor = WATCHDOG_MINOR,
218 .name = "watchdog",
219 .fops = &ks8695wdt_fops,
220};
221
222static int __init ks8695wdt_probe(struct platform_device *pdev)
223{
224 int res;
225
226 if (ks8695wdt_miscdev.parent)
227 return -EBUSY;
228 ks8695wdt_miscdev.parent = &pdev->dev;
229
230 res = misc_register(&ks8695wdt_miscdev);
231 if (res)
232 return res;
233
234 printk("KS8695 Watchdog Timer enabled (%d seconds%s)\n", wdt_time, nowayout ? ", nowayout" : "");
235 return 0;
236}
237
238static int __exit ks8695wdt_remove(struct platform_device *pdev)
239{
240 int res;
241
242 res = misc_deregister(&ks8695wdt_miscdev);
243 if (!res)
244 ks8695wdt_miscdev.parent = NULL;
245
246 return res;
247}
248
249static void ks8695wdt_shutdown(struct platform_device *pdev)
250{
251 ks8695_wdt_stop();
252}
253
254#ifdef CONFIG_PM
255
256static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message)
257{
258 ks8695_wdt_stop();
259 return 0;
260}
261
262static int ks8695wdt_resume(struct platform_device *pdev)
263{
264 if (ks8695wdt_busy)
265 ks8695_wdt_start();
266 return 0;
267}
268
269#else
270#define ks8695wdt_suspend NULL
271#define ks8695wdt_resume NULL
272#endif
273
274static struct platform_driver ks8695wdt_driver = {
275 .probe = ks8695wdt_probe,
276 .remove = __exit_p(ks8695wdt_remove),
277 .shutdown = ks8695wdt_shutdown,
278 .suspend = ks8695wdt_suspend,
279 .resume = ks8695wdt_resume,
280 .driver = {
281 .name = "ks8695_wdt",
282 .owner = THIS_MODULE,
283 },
284};
285
286static int __init ks8695_wdt_init(void)
287{
288 /* Check that the heartbeat value is within range; if not reset to the default */
289 if (ks8695_wdt_settimeout(wdt_time)) {
290 ks8695_wdt_settimeout(WDT_DEFAULT_TIME);
291 pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i, using %d\n", wdt_time, WDT_MAX_TIME);
292 }
293
294 return platform_driver_register(&ks8695wdt_driver);
295}
296
297static void __exit ks8695_wdt_exit(void)
298{
299 platform_driver_unregister(&ks8695wdt_driver);
300}
301
302module_init(ks8695_wdt_init);
303module_exit(ks8695_wdt_exit);
304
305MODULE_AUTHOR("Andrew Victor");
306MODULE_DESCRIPTION("Watchdog driver for KS8695");
307MODULE_LICENSE("GPL");
308MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Kay Sieversf37d1932008-04-10 21:29:23 -0700309MODULE_ALIAS("platform:ks8695_wdt");