Commit | Line | Data |
---|---|---|
ccb8f430 AV |
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 | ||
1977f032 | 11 | #include <linux/bitops.h> |
ccb8f430 AV |
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> | |
f4fabce1 AC |
22 | #include <linux/io.h> |
23 | #include <linux/uaccess.h> | |
568dba66 | 24 | #include <mach/hardware.h> |
a09e64fb | 25 | #include <mach/regs-timer.h> |
ccb8f430 | 26 | |
ccb8f430 AV |
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); | |
f4fabce1 AC |
34 | MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default=" |
35 | __MODULE_STRING(WDT_DEFAULT_TIME) ")"); | |
ccb8f430 AV |
36 | |
37 | #ifdef CONFIG_WATCHDOG_NOWAYOUT | |
38 | module_param(nowayout, int, 0); | |
f4fabce1 AC |
39 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
40 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
ccb8f430 AV |
41 | #endif |
42 | ||
43 | ||
44 | static unsigned long ks8695wdt_busy; | |
f4fabce1 | 45 | static spinlock_t ks8695_lock; |
ccb8f430 AV |
46 | |
47 | /* ......................................................................... */ | |
48 | ||
49 | /* | |
50 | * Disable the watchdog. | |
51 | */ | |
f4fabce1 | 52 | static inline void ks8695_wdt_stop(void) |
ccb8f430 AV |
53 | { |
54 | unsigned long tmcon; | |
55 | ||
f4fabce1 | 56 | spin_lock(&ks8695_lock); |
ccb8f430 AV |
57 | /* disable timer0 */ |
58 | tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON); | |
59 | __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); | |
f4fabce1 | 60 | spin_unlock(&ks8695_lock); |
ccb8f430 AV |
61 | } |
62 | ||
63 | /* | |
64 | * Enable and reset the watchdog. | |
65 | */ | |
f4fabce1 | 66 | static inline void ks8695_wdt_start(void) |
ccb8f430 AV |
67 | { |
68 | unsigned long tmcon; | |
0a51810a | 69 | unsigned long tval = wdt_time * KS8695_CLOCK_RATE; |
ccb8f430 | 70 | |
f4fabce1 | 71 | spin_lock(&ks8695_lock); |
ccb8f430 AV |
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); | |
f4fabce1 | 82 | spin_unlock(&ks8695_lock); |
ccb8f430 AV |
83 | } |
84 | ||
85 | /* | |
86 | * Reload the watchdog timer. (ie, pat the watchdog) | |
87 | */ | |
f4fabce1 | 88 | static inline void ks8695_wdt_reload(void) |
ccb8f430 AV |
89 | { |
90 | unsigned long tmcon; | |
91 | ||
f4fabce1 | 92 | spin_lock(&ks8695_lock); |
ccb8f430 AV |
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); | |
f4fabce1 | 97 | spin_unlock(&ks8695_lock); |
ccb8f430 AV |
98 | } |
99 | ||
100 | /* | |
101 | * Change the watchdog time interval. | |
102 | */ | |
103 | static int ks8695_wdt_settimeout(int new_time) | |
104 | { | |
105 | /* | |
0a51810a | 106 | * All counting occurs at KS8695_CLOCK_RATE / 128 = 0.256 Hz |
ccb8f430 AV |
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 | ||
f4fabce1 AC |
114 | /* Set new watchdog time. It will be used when |
115 | ks8695_wdt_start() is called. */ | |
ccb8f430 AV |
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 | { | |
f4fabce1 | 141 | /* Disable the watchdog when file is closed */ |
ccb8f430 | 142 | if (!nowayout) |
f4fabce1 | 143 | ks8695_wdt_stop(); |
ccb8f430 AV |
144 | clear_bit(0, &ks8695wdt_busy); |
145 | return 0; | |
146 | } | |
147 | ||
42747d71 | 148 | static const struct watchdog_info ks8695_wdt_info = { |
ccb8f430 AV |
149 | .identity = "ks8695 watchdog", |
150 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, | |
151 | }; | |
152 | ||
153 | /* | |
154 | * Handle commands from user-space. | |
155 | */ | |
f4fabce1 AC |
156 | static long ks8695_wdt_ioctl(struct file *file, unsigned int cmd, |
157 | unsigned long arg) | |
ccb8f430 AV |
158 | { |
159 | void __user *argp = (void __user *)arg; | |
160 | int __user *p = argp; | |
161 | int new_value; | |
162 | ||
f4fabce1 | 163 | switch (cmd) { |
f4fabce1 AC |
164 | case WDIOC_GETSUPPORT: |
165 | return copy_to_user(argp, &ks8695_wdt_info, | |
166 | sizeof(ks8695_wdt_info)) ? -EFAULT : 0; | |
f4fabce1 AC |
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) | |
ccb8f430 | 176 | ks8695_wdt_start(); |
f4fabce1 | 177 | return 0; |
0c06090c WVS |
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); | |
f4fabce1 AC |
192 | default: |
193 | return -ENOTTY; | |
ccb8f430 AV |
194 | } |
195 | } | |
196 | ||
197 | /* | |
198 | * Pat the watchdog whenever device is written to. | |
199 | */ | |
f4fabce1 AC |
200 | static ssize_t ks8695_wdt_write(struct file *file, const char *data, |
201 | size_t len, loff_t *ppos) | |
ccb8f430 AV |
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, | |
f4fabce1 | 212 | .unlocked_ioctl = ks8695_wdt_ioctl, |
ccb8f430 AV |
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 | ||
c98d58e0 | 224 | static int __devinit ks8695wdt_probe(struct platform_device *pdev) |
ccb8f430 AV |
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 | ||
f4fabce1 AC |
236 | printk(KERN_INFO "KS8695 Watchdog Timer enabled (%d seconds%s)\n", |
237 | wdt_time, nowayout ? ", nowayout" : ""); | |
ccb8f430 AV |
238 | return 0; |
239 | } | |
240 | ||
c98d58e0 | 241 | static int __devexit ks8695wdt_remove(struct platform_device *pdev) |
ccb8f430 AV |
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, | |
c98d58e0 | 279 | .remove = __devexit_p(ks8695wdt_remove), |
ccb8f430 AV |
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 | { | |
f4fabce1 AC |
291 | spin_lock_init(&ks8695_lock); |
292 | /* Check that the heartbeat value is within range; | |
293 | if not reset to the default */ | |
ccb8f430 AV |
294 | if (ks8695_wdt_settimeout(wdt_time)) { |
295 | ks8695_wdt_settimeout(WDT_DEFAULT_TIME); | |
a77dba7e WVS |
296 | pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i" |
297 | ", using %d\n", wdt_time, WDT_MAX_TIME); | |
ccb8f430 | 298 | } |
ccb8f430 AV |
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); | |
f37d193c | 314 | MODULE_ALIAS("platform:ks8695_wdt"); |