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1/*
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
11#include <linux/bitops.h>
12#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>
22#include <linux/io.h>
23#include <linux/uaccess.h>
24#include <mach/hardware.h>
25#include <mach/regs-timer.h>
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="
35 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
36
37#ifdef CONFIG_WATCHDOG_NOWAYOUT
38module_param(nowayout, int, 0);
39MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
40 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
41#endif
42
43
44static unsigned long ks8695wdt_busy;
45static spinlock_t ks8695_lock;
46
47/* ......................................................................... */
48
49/*
50 * Disable the watchdog.
51 */
52static inline void ks8695_wdt_stop(void)
53{
54 unsigned long tmcon;
55
56 spin_lock(&ks8695_lock);
57 /* disable timer0 */
58 tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
59 __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
60 spin_unlock(&ks8695_lock);
61}
62
63/*
64 * Enable and reset the watchdog.
65 */
66static inline void ks8695_wdt_start(void)
67{
68 unsigned long tmcon;
69 unsigned long tval = wdt_time * KS8695_CLOCK_RATE;
70
71 spin_lock(&ks8695_lock);
72 /* disable timer0 */
73 tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
74 __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
75
76 /* program timer0 */
77 __raw_writel(tval | T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC);
78
79 /* re-enable timer0 */
80 tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
81 __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
82 spin_unlock(&ks8695_lock);
83}
84
85/*
86 * Reload the watchdog timer. (ie, pat the watchdog)
87 */
88static inline void ks8695_wdt_reload(void)
89{
90 unsigned long tmcon;
91
92 spin_lock(&ks8695_lock);
93 /* disable, then re-enable timer0 */
94 tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
95 __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
96 __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
97 spin_unlock(&ks8695_lock);
98}
99
100/*
101 * Change the watchdog time interval.
102 */
103static int ks8695_wdt_settimeout(int new_time)
104{
105 /*
106 * All counting occurs at KS8695_CLOCK_RATE / 128 = 0.256 Hz
107 *
108 * Since WDV is a 16-bit counter, the maximum period is
109 * 65536 / 0.256 = 256 seconds.
110 */
111 if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
112 return -EINVAL;
113
114 /* Set new watchdog time. It will be used when
115 ks8695_wdt_start() is called. */
116 wdt_time = new_time;
117 return 0;
118}
119
120/* ......................................................................... */
121
122/*
123 * Watchdog device is opened, and watchdog starts running.
124 */
125static int ks8695_wdt_open(struct inode *inode, struct file *file)
126{
127 if (test_and_set_bit(0, &ks8695wdt_busy))
128 return -EBUSY;
129
130 ks8695_wdt_start();
131 return nonseekable_open(inode, file);
132}
133
134/*
135 * Close the watchdog device.
136 * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
137 * disabled.
138 */
139static int ks8695_wdt_close(struct inode *inode, struct file *file)
140{
141 /* Disable the watchdog when file is closed */
142 if (!nowayout)
143 ks8695_wdt_stop();
144 clear_bit(0, &ks8695wdt_busy);
145 return 0;
146}
147
148static const struct watchdog_info ks8695_wdt_info = {
149 .identity = "ks8695 watchdog",
150 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
151};
152
153/*
154 * Handle commands from user-space.
155 */
156static long ks8695_wdt_ioctl(struct file *file, unsigned int cmd,
157 unsigned long arg)
158{
159 void __user *argp = (void __user *)arg;
160 int __user *p = argp;
161 int new_value;
162
163 switch (cmd) {
164 case WDIOC_GETSUPPORT:
165 return copy_to_user(argp, &ks8695_wdt_info,
166 sizeof(ks8695_wdt_info)) ? -EFAULT : 0;
167 case WDIOC_GETSTATUS:
168 case WDIOC_GETBOOTSTATUS:
169 return put_user(0, p);
170 case WDIOC_SETOPTIONS:
171 if (get_user(new_value, p))
172 return -EFAULT;
173 if (new_value & WDIOS_DISABLECARD)
174 ks8695_wdt_stop();
175 if (new_value & WDIOS_ENABLECARD)
176 ks8695_wdt_start();
177 return 0;
178 case WDIOC_KEEPALIVE:
179 ks8695_wdt_reload(); /* pat the watchdog */
180 return 0;
181 case WDIOC_SETTIMEOUT:
182 if (get_user(new_value, p))
183 return -EFAULT;
184 if (ks8695_wdt_settimeout(new_value))
185 return -EINVAL;
186 /* Enable new time value */
187 ks8695_wdt_start();
188 /* Return current value */
189 return put_user(wdt_time, p);
190 case WDIOC_GETTIMEOUT:
191 return put_user(wdt_time, p);
192 default:
193 return -ENOTTY;
194 }
195}
196
197/*
198 * Pat the watchdog whenever device is written to.
199 */
200static ssize_t ks8695_wdt_write(struct file *file, const char *data,
201 size_t len, loff_t *ppos)
202{
203 ks8695_wdt_reload(); /* pat the watchdog */
204 return len;
205}
206
207/* ......................................................................... */
208
209static const struct file_operations ks8695wdt_fops = {
210 .owner = THIS_MODULE,
211 .llseek = no_llseek,
212 .unlocked_ioctl = ks8695_wdt_ioctl,
213 .open = ks8695_wdt_open,
214 .release = ks8695_wdt_close,
215 .write = ks8695_wdt_write,
216};
217
218static struct miscdevice ks8695wdt_miscdev = {
219 .minor = WATCHDOG_MINOR,
220 .name = "watchdog",
221 .fops = &ks8695wdt_fops,
222};
223
224static int __devinit ks8695wdt_probe(struct platform_device *pdev)
225{
226 int res;
227
228 if (ks8695wdt_miscdev.parent)
229 return -EBUSY;
230 ks8695wdt_miscdev.parent = &pdev->dev;
231
232 res = misc_register(&ks8695wdt_miscdev);
233 if (res)
234 return res;
235
236 printk(KERN_INFO "KS8695 Watchdog Timer enabled (%d seconds%s)\n",
237 wdt_time, nowayout ? ", nowayout" : "");
238 return 0;
239}
240
241static int __devexit ks8695wdt_remove(struct platform_device *pdev)
242{
243 int res;
244
245 res = misc_deregister(&ks8695wdt_miscdev);
246 if (!res)
247 ks8695wdt_miscdev.parent = NULL;
248
249 return res;
250}
251
252static void ks8695wdt_shutdown(struct platform_device *pdev)
253{
254 ks8695_wdt_stop();
255}
256
257#ifdef CONFIG_PM
258
259static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message)
260{
261 ks8695_wdt_stop();
262 return 0;
263}
264
265static int ks8695wdt_resume(struct platform_device *pdev)
266{
267 if (ks8695wdt_busy)
268 ks8695_wdt_start();
269 return 0;
270}
271
272#else
273#define ks8695wdt_suspend NULL
274#define ks8695wdt_resume NULL
275#endif
276
277static struct platform_driver ks8695wdt_driver = {
278 .probe = ks8695wdt_probe,
279 .remove = __devexit_p(ks8695wdt_remove),
280 .shutdown = ks8695wdt_shutdown,
281 .suspend = ks8695wdt_suspend,
282 .resume = ks8695wdt_resume,
283 .driver = {
284 .name = "ks8695_wdt",
285 .owner = THIS_MODULE,
286 },
287};
288
289static int __init ks8695_wdt_init(void)
290{
291 spin_lock_init(&ks8695_lock);
292 /* Check that the heartbeat value is within range;
293 if not reset to the default */
294 if (ks8695_wdt_settimeout(wdt_time)) {
295 ks8695_wdt_settimeout(WDT_DEFAULT_TIME);
296 pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i"
297 ", using %d\n", wdt_time, WDT_MAX_TIME);
298 }
299 return platform_driver_register(&ks8695wdt_driver);
300}
301
302static void __exit ks8695_wdt_exit(void)
303{
304 platform_driver_unregister(&ks8695wdt_driver);
305}
306
307module_init(ks8695_wdt_init);
308module_exit(ks8695_wdt_exit);
309
310MODULE_AUTHOR("Andrew Victor");
311MODULE_DESCRIPTION("Watchdog driver for KS8695");
312MODULE_LICENSE("GPL");
313MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
314MODULE_ALIAS("platform:ks8695_wdt");
1/*
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
11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13#include <linux/bitops.h>
14#include <linux/errno.h>
15#include <linux/fs.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>
24#include <linux/io.h>
25#include <linux/uaccess.h>
26#include <mach/hardware.h>
27
28#define KS8695_TMR_OFFSET (0xF0000 + 0xE400)
29#define KS8695_TMR_VA (KS8695_IO_VA + KS8695_TMR_OFFSET)
30
31/*
32 * Timer registers
33 */
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 */
37
38/* Timer0 Timeout Counter Register */
39#define T0TC_WATCHDOG (0xff) /* Enable watchdog mode */
40
41#define WDT_DEFAULT_TIME 5 /* seconds */
42#define WDT_MAX_TIME 171 /* seconds */
43
44static int wdt_time = WDT_DEFAULT_TIME;
45static bool nowayout = WATCHDOG_NOWAYOUT;
46
47module_param(wdt_time, int, 0);
48MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
49 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
50
51#ifdef CONFIG_WATCHDOG_NOWAYOUT
52module_param(nowayout, bool, 0);
53MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
54 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
55#endif
56
57
58static unsigned long ks8695wdt_busy;
59static DEFINE_SPINLOCK(ks8695_lock);
60
61/* ......................................................................... */
62
63/*
64 * Disable the watchdog.
65 */
66static inline void ks8695_wdt_stop(void)
67{
68 unsigned long tmcon;
69
70 spin_lock(&ks8695_lock);
71 /* disable timer0 */
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);
75}
76
77/*
78 * Enable and reset the watchdog.
79 */
80static inline void ks8695_wdt_start(void)
81{
82 unsigned long tmcon;
83 unsigned long tval = wdt_time * KS8695_CLOCK_RATE;
84
85 spin_lock(&ks8695_lock);
86 /* disable timer0 */
87 tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
88 __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
89
90 /* program timer0 */
91 __raw_writel(tval | T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC);
92
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);
97}
98
99/*
100 * Reload the watchdog timer. (ie, pat the watchdog)
101 */
102static inline void ks8695_wdt_reload(void)
103{
104 unsigned long tmcon;
105
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);
112}
113
114/*
115 * Change the watchdog time interval.
116 */
117static int ks8695_wdt_settimeout(int new_time)
118{
119 /*
120 * All counting occurs at KS8695_CLOCK_RATE / 128 = 0.256 Hz
121 *
122 * Since WDV is a 16-bit counter, the maximum period is
123 * 65536 / 0.256 = 256 seconds.
124 */
125 if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
126 return -EINVAL;
127
128 /* Set new watchdog time. It will be used when
129 ks8695_wdt_start() is called. */
130 wdt_time = new_time;
131 return 0;
132}
133
134/* ......................................................................... */
135
136/*
137 * Watchdog device is opened, and watchdog starts running.
138 */
139static int ks8695_wdt_open(struct inode *inode, struct file *file)
140{
141 if (test_and_set_bit(0, &ks8695wdt_busy))
142 return -EBUSY;
143
144 ks8695_wdt_start();
145 return nonseekable_open(inode, file);
146}
147
148/*
149 * Close the watchdog device.
150 * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
151 * disabled.
152 */
153static int ks8695_wdt_close(struct inode *inode, struct file *file)
154{
155 /* Disable the watchdog when file is closed */
156 if (!nowayout)
157 ks8695_wdt_stop();
158 clear_bit(0, &ks8695wdt_busy);
159 return 0;
160}
161
162static const struct watchdog_info ks8695_wdt_info = {
163 .identity = "ks8695 watchdog",
164 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
165};
166
167/*
168 * Handle commands from user-space.
169 */
170static long ks8695_wdt_ioctl(struct file *file, unsigned int cmd,
171 unsigned long arg)
172{
173 void __user *argp = (void __user *)arg;
174 int __user *p = argp;
175 int new_value;
176
177 switch (cmd) {
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))
186 return -EFAULT;
187 if (new_value & WDIOS_DISABLECARD)
188 ks8695_wdt_stop();
189 if (new_value & WDIOS_ENABLECARD)
190 ks8695_wdt_start();
191 return 0;
192 case WDIOC_KEEPALIVE:
193 ks8695_wdt_reload(); /* pat the watchdog */
194 return 0;
195 case WDIOC_SETTIMEOUT:
196 if (get_user(new_value, p))
197 return -EFAULT;
198 if (ks8695_wdt_settimeout(new_value))
199 return -EINVAL;
200 /* Enable new time value */
201 ks8695_wdt_start();
202 /* Return current value */
203 return put_user(wdt_time, p);
204 case WDIOC_GETTIMEOUT:
205 return put_user(wdt_time, p);
206 default:
207 return -ENOTTY;
208 }
209}
210
211/*
212 * Pat the watchdog whenever device is written to.
213 */
214static ssize_t ks8695_wdt_write(struct file *file, const char *data,
215 size_t len, loff_t *ppos)
216{
217 ks8695_wdt_reload(); /* pat the watchdog */
218 return len;
219}
220
221/* ......................................................................... */
222
223static const struct file_operations ks8695wdt_fops = {
224 .owner = THIS_MODULE,
225 .llseek = no_llseek,
226 .unlocked_ioctl = ks8695_wdt_ioctl,
227 .open = ks8695_wdt_open,
228 .release = ks8695_wdt_close,
229 .write = ks8695_wdt_write,
230};
231
232static struct miscdevice ks8695wdt_miscdev = {
233 .minor = WATCHDOG_MINOR,
234 .name = "watchdog",
235 .fops = &ks8695wdt_fops,
236};
237
238static int ks8695wdt_probe(struct platform_device *pdev)
239{
240 int res;
241
242 if (ks8695wdt_miscdev.parent)
243 return -EBUSY;
244 ks8695wdt_miscdev.parent = &pdev->dev;
245
246 res = misc_register(&ks8695wdt_miscdev);
247 if (res)
248 return res;
249
250 pr_info("KS8695 Watchdog Timer enabled (%d seconds%s)\n",
251 wdt_time, nowayout ? ", nowayout" : "");
252 return 0;
253}
254
255static int ks8695wdt_remove(struct platform_device *pdev)
256{
257 int res;
258
259 res = misc_deregister(&ks8695wdt_miscdev);
260 if (!res)
261 ks8695wdt_miscdev.parent = NULL;
262
263 return res;
264}
265
266static void ks8695wdt_shutdown(struct platform_device *pdev)
267{
268 ks8695_wdt_stop();
269}
270
271#ifdef CONFIG_PM
272
273static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message)
274{
275 ks8695_wdt_stop();
276 return 0;
277}
278
279static int ks8695wdt_resume(struct platform_device *pdev)
280{
281 if (ks8695wdt_busy)
282 ks8695_wdt_start();
283 return 0;
284}
285
286#else
287#define ks8695wdt_suspend NULL
288#define ks8695wdt_resume NULL
289#endif
290
291static struct platform_driver ks8695wdt_driver = {
292 .probe = ks8695wdt_probe,
293 .remove = ks8695wdt_remove,
294 .shutdown = ks8695wdt_shutdown,
295 .suspend = ks8695wdt_suspend,
296 .resume = ks8695wdt_resume,
297 .driver = {
298 .name = "ks8695_wdt",
299 .owner = THIS_MODULE,
300 },
301};
302
303static int __init ks8695_wdt_init(void)
304{
305 /* Check that the heartbeat value is within range;
306 if not reset to the default */
307 if (ks8695_wdt_settimeout(wdt_time)) {
308 ks8695_wdt_settimeout(WDT_DEFAULT_TIME);
309 pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i"
310 ", using %d\n", wdt_time, WDT_MAX_TIME);
311 }
312 return platform_driver_register(&ks8695wdt_driver);
313}
314
315static void __exit ks8695_wdt_exit(void)
316{
317 platform_driver_unregister(&ks8695wdt_driver);
318}
319
320module_init(ks8695_wdt_init);
321module_exit(ks8695_wdt_exit);
322
323MODULE_AUTHOR("Andrew Victor");
324MODULE_DESCRIPTION("Watchdog driver for KS8695");
325MODULE_LICENSE("GPL");
326MODULE_ALIAS("platform:ks8695_wdt");