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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/timex.h> |
25 | #include <mach/regs-timer.h> |
26 | |
27 | #define WDT_DEFAULT_TIME 5 /* seconds */ |
28 | #define WDT_MAX_TIME 171 /* seconds */ |
29 | |
30 | static int wdt_time = WDT_DEFAULT_TIME; |
31 | static int nowayout = WATCHDOG_NOWAYOUT; |
32 | |
33 | module_param(wdt_time, int, 0); |
34 | MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default=" |
35 | __MODULE_STRING(WDT_DEFAULT_TIME) ")"); |
36 | |
37 | #ifdef CONFIG_WATCHDOG_NOWAYOUT |
38 | module_param(nowayout, int, 0); |
39 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
40 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
41 | #endif |
42 | |
43 | |
44 | static unsigned long ks8695wdt_busy; |
45 | static spinlock_t ks8695_lock; |
46 | |
47 | /* ......................................................................... */ |
48 | |
49 | /* |
50 | * Disable the watchdog. |
51 | */ |
52 | static 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 | */ |
66 | static 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 | */ |
88 | static 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 | */ |
103 | static 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 | */ |
125 | static 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 | */ |
139 | static 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 | |
148 | static 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 | */ |
156 | static 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 | */ |
200 | static 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 | |
209 | static 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 | |
218 | static struct miscdevice ks8695wdt_miscdev = { |
219 | .minor = WATCHDOG_MINOR, |
220 | .name = "watchdog", |
221 | .fops = &ks8695wdt_fops, |
222 | }; |
223 | |
224 | static 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 | |
241 | static 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 | |
252 | static void ks8695wdt_shutdown(struct platform_device *pdev) |
253 | { |
254 | ks8695_wdt_stop(); |
255 | } |
256 | |
257 | #ifdef CONFIG_PM |
258 | |
259 | static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message) |
260 | { |
261 | ks8695_wdt_stop(); |
262 | return 0; |
263 | } |
264 | |
265 | static 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 | |
277 | static 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 | |
289 | static 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 | |
302 | static void __exit ks8695_wdt_exit(void) |
303 | { |
304 | platform_driver_unregister(&ks8695wdt_driver); |
305 | } |
306 | |
307 | module_init(ks8695_wdt_init); |
308 | module_exit(ks8695_wdt_exit); |
309 | |
310 | MODULE_AUTHOR("Andrew Victor"); |
311 | MODULE_DESCRIPTION("Watchdog driver for KS8695"); |
312 | MODULE_LICENSE("GPL"); |
313 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
314 | MODULE_ALIAS("platform:ks8695_wdt"); |
315 |
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