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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 | #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 | #include <mach/regs-timer.h> |
28 | |
29 | #define WDT_DEFAULT_TIME 5 /* seconds */ |
30 | #define WDT_MAX_TIME 171 /* seconds */ |
31 | |
32 | static int wdt_time = WDT_DEFAULT_TIME; |
33 | static bool nowayout = WATCHDOG_NOWAYOUT; |
34 | |
35 | module_param(wdt_time, int, 0); |
36 | MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default=" |
37 | __MODULE_STRING(WDT_DEFAULT_TIME) ")"); |
38 | |
39 | #ifdef CONFIG_WATCHDOG_NOWAYOUT |
40 | module_param(nowayout, bool, 0); |
41 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
42 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
43 | #endif |
44 | |
45 | |
46 | static unsigned long ks8695wdt_busy; |
47 | static DEFINE_SPINLOCK(ks8695_lock); |
48 | |
49 | /* ......................................................................... */ |
50 | |
51 | /* |
52 | * Disable the watchdog. |
53 | */ |
54 | static inline void ks8695_wdt_stop(void) |
55 | { |
56 | unsigned long tmcon; |
57 | |
58 | spin_lock(&ks8695_lock); |
59 | /* disable timer0 */ |
60 | tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON); |
61 | __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); |
62 | spin_unlock(&ks8695_lock); |
63 | } |
64 | |
65 | /* |
66 | * Enable and reset the watchdog. |
67 | */ |
68 | static inline void ks8695_wdt_start(void) |
69 | { |
70 | unsigned long tmcon; |
71 | unsigned long tval = wdt_time * KS8695_CLOCK_RATE; |
72 | |
73 | spin_lock(&ks8695_lock); |
74 | /* disable timer0 */ |
75 | tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON); |
76 | __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); |
77 | |
78 | /* program timer0 */ |
79 | __raw_writel(tval | T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC); |
80 | |
81 | /* re-enable timer0 */ |
82 | tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON); |
83 | __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); |
84 | spin_unlock(&ks8695_lock); |
85 | } |
86 | |
87 | /* |
88 | * Reload the watchdog timer. (ie, pat the watchdog) |
89 | */ |
90 | static inline void ks8695_wdt_reload(void) |
91 | { |
92 | unsigned long tmcon; |
93 | |
94 | spin_lock(&ks8695_lock); |
95 | /* disable, then re-enable timer0 */ |
96 | tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON); |
97 | __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); |
98 | __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); |
99 | spin_unlock(&ks8695_lock); |
100 | } |
101 | |
102 | /* |
103 | * Change the watchdog time interval. |
104 | */ |
105 | static int ks8695_wdt_settimeout(int new_time) |
106 | { |
107 | /* |
108 | * All counting occurs at KS8695_CLOCK_RATE / 128 = 0.256 Hz |
109 | * |
110 | * Since WDV is a 16-bit counter, the maximum period is |
111 | * 65536 / 0.256 = 256 seconds. |
112 | */ |
113 | if ((new_time <= 0) || (new_time > WDT_MAX_TIME)) |
114 | return -EINVAL; |
115 | |
116 | /* Set new watchdog time. It will be used when |
117 | ks8695_wdt_start() is called. */ |
118 | wdt_time = new_time; |
119 | return 0; |
120 | } |
121 | |
122 | /* ......................................................................... */ |
123 | |
124 | /* |
125 | * Watchdog device is opened, and watchdog starts running. |
126 | */ |
127 | static int ks8695_wdt_open(struct inode *inode, struct file *file) |
128 | { |
129 | if (test_and_set_bit(0, &ks8695wdt_busy)) |
130 | return -EBUSY; |
131 | |
132 | ks8695_wdt_start(); |
133 | return nonseekable_open(inode, file); |
134 | } |
135 | |
136 | /* |
137 | * Close the watchdog device. |
138 | * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also |
139 | * disabled. |
140 | */ |
141 | static int ks8695_wdt_close(struct inode *inode, struct file *file) |
142 | { |
143 | /* Disable the watchdog when file is closed */ |
144 | if (!nowayout) |
145 | ks8695_wdt_stop(); |
146 | clear_bit(0, &ks8695wdt_busy); |
147 | return 0; |
148 | } |
149 | |
150 | static const struct watchdog_info ks8695_wdt_info = { |
151 | .identity = "ks8695 watchdog", |
152 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, |
153 | }; |
154 | |
155 | /* |
156 | * Handle commands from user-space. |
157 | */ |
158 | static long ks8695_wdt_ioctl(struct file *file, unsigned int cmd, |
159 | unsigned long arg) |
160 | { |
161 | void __user *argp = (void __user *)arg; |
162 | int __user *p = argp; |
163 | int new_value; |
164 | |
165 | switch (cmd) { |
166 | case WDIOC_GETSUPPORT: |
167 | return copy_to_user(argp, &ks8695_wdt_info, |
168 | sizeof(ks8695_wdt_info)) ? -EFAULT : 0; |
169 | case WDIOC_GETSTATUS: |
170 | case WDIOC_GETBOOTSTATUS: |
171 | return put_user(0, p); |
172 | case WDIOC_SETOPTIONS: |
173 | if (get_user(new_value, p)) |
174 | return -EFAULT; |
175 | if (new_value & WDIOS_DISABLECARD) |
176 | ks8695_wdt_stop(); |
177 | if (new_value & WDIOS_ENABLECARD) |
178 | ks8695_wdt_start(); |
179 | return 0; |
180 | case WDIOC_KEEPALIVE: |
181 | ks8695_wdt_reload(); /* pat the watchdog */ |
182 | return 0; |
183 | case WDIOC_SETTIMEOUT: |
184 | if (get_user(new_value, p)) |
185 | return -EFAULT; |
186 | if (ks8695_wdt_settimeout(new_value)) |
187 | return -EINVAL; |
188 | /* Enable new time value */ |
189 | ks8695_wdt_start(); |
190 | /* Return current value */ |
191 | return put_user(wdt_time, p); |
192 | case WDIOC_GETTIMEOUT: |
193 | return put_user(wdt_time, p); |
194 | default: |
195 | return -ENOTTY; |
196 | } |
197 | } |
198 | |
199 | /* |
200 | * Pat the watchdog whenever device is written to. |
201 | */ |
202 | static ssize_t ks8695_wdt_write(struct file *file, const char *data, |
203 | size_t len, loff_t *ppos) |
204 | { |
205 | ks8695_wdt_reload(); /* pat the watchdog */ |
206 | return len; |
207 | } |
208 | |
209 | /* ......................................................................... */ |
210 | |
211 | static const struct file_operations ks8695wdt_fops = { |
212 | .owner = THIS_MODULE, |
213 | .llseek = no_llseek, |
214 | .unlocked_ioctl = ks8695_wdt_ioctl, |
215 | .open = ks8695_wdt_open, |
216 | .release = ks8695_wdt_close, |
217 | .write = ks8695_wdt_write, |
218 | }; |
219 | |
220 | static struct miscdevice ks8695wdt_miscdev = { |
221 | .minor = WATCHDOG_MINOR, |
222 | .name = "watchdog", |
223 | .fops = &ks8695wdt_fops, |
224 | }; |
225 | |
226 | static int __devinit ks8695wdt_probe(struct platform_device *pdev) |
227 | { |
228 | int res; |
229 | |
230 | if (ks8695wdt_miscdev.parent) |
231 | return -EBUSY; |
232 | ks8695wdt_miscdev.parent = &pdev->dev; |
233 | |
234 | res = misc_register(&ks8695wdt_miscdev); |
235 | if (res) |
236 | return res; |
237 | |
238 | pr_info("KS8695 Watchdog Timer enabled (%d seconds%s)\n", |
239 | wdt_time, nowayout ? ", nowayout" : ""); |
240 | return 0; |
241 | } |
242 | |
243 | static int __devexit ks8695wdt_remove(struct platform_device *pdev) |
244 | { |
245 | int res; |
246 | |
247 | res = misc_deregister(&ks8695wdt_miscdev); |
248 | if (!res) |
249 | ks8695wdt_miscdev.parent = NULL; |
250 | |
251 | return res; |
252 | } |
253 | |
254 | static void ks8695wdt_shutdown(struct platform_device *pdev) |
255 | { |
256 | ks8695_wdt_stop(); |
257 | } |
258 | |
259 | #ifdef CONFIG_PM |
260 | |
261 | static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message) |
262 | { |
263 | ks8695_wdt_stop(); |
264 | return 0; |
265 | } |
266 | |
267 | static int ks8695wdt_resume(struct platform_device *pdev) |
268 | { |
269 | if (ks8695wdt_busy) |
270 | ks8695_wdt_start(); |
271 | return 0; |
272 | } |
273 | |
274 | #else |
275 | #define ks8695wdt_suspend NULL |
276 | #define ks8695wdt_resume NULL |
277 | #endif |
278 | |
279 | static struct platform_driver ks8695wdt_driver = { |
280 | .probe = ks8695wdt_probe, |
281 | .remove = __devexit_p(ks8695wdt_remove), |
282 | .shutdown = ks8695wdt_shutdown, |
283 | .suspend = ks8695wdt_suspend, |
284 | .resume = ks8695wdt_resume, |
285 | .driver = { |
286 | .name = "ks8695_wdt", |
287 | .owner = THIS_MODULE, |
288 | }, |
289 | }; |
290 | |
291 | static int __init ks8695_wdt_init(void) |
292 | { |
293 | /* Check that the heartbeat value is within range; |
294 | if not reset to the default */ |
295 | if (ks8695_wdt_settimeout(wdt_time)) { |
296 | ks8695_wdt_settimeout(WDT_DEFAULT_TIME); |
297 | pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i" |
298 | ", using %d\n", wdt_time, WDT_MAX_TIME); |
299 | } |
300 | return platform_driver_register(&ks8695wdt_driver); |
301 | } |
302 | |
303 | static void __exit ks8695_wdt_exit(void) |
304 | { |
305 | platform_driver_unregister(&ks8695wdt_driver); |
306 | } |
307 | |
308 | module_init(ks8695_wdt_init); |
309 | module_exit(ks8695_wdt_exit); |
310 | |
311 | MODULE_AUTHOR("Andrew Victor"); |
312 | MODULE_DESCRIPTION("Watchdog driver for KS8695"); |
313 | MODULE_LICENSE("GPL"); |
314 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
315 | MODULE_ALIAS("platform:ks8695_wdt"); |
316 |
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