Commit | Line | Data |
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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> | |
ccb8f430 AV |
22 | #include <asm/io.h> |
23 | #include <asm/uaccess.h> | |
24 | #include <asm/arch/regs-timer.h> | |
25 | ||
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="__MODULE_STRING(WDT_DEFAULT_TIME) ")"); | |
35 | ||
36 | #ifdef CONFIG_WATCHDOG_NOWAYOUT | |
37 | module_param(nowayout, int, 0); | |
38 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
39 | #endif | |
40 | ||
41 | ||
42 | static unsigned long ks8695wdt_busy; | |
43 | ||
44 | /* ......................................................................... */ | |
45 | ||
46 | /* | |
47 | * Disable the watchdog. | |
48 | */ | |
49 | static 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 | */ | |
61 | static 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 | */ | |
81 | static 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 | */ | |
94 | static 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 | */ | |
115 | static 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 | */ | |
129 | static 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 | ||
138 | static 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 | */ | |
146 | static 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 | */ | |
199 | static 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 | ||
207 | static 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 | ||
216 | static struct miscdevice ks8695wdt_miscdev = { | |
217 | .minor = WATCHDOG_MINOR, | |
218 | .name = "watchdog", | |
219 | .fops = &ks8695wdt_fops, | |
220 | }; | |
221 | ||
222 | static 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 | ||
238 | static 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 | ||
249 | static void ks8695wdt_shutdown(struct platform_device *pdev) | |
250 | { | |
251 | ks8695_wdt_stop(); | |
252 | } | |
253 | ||
254 | #ifdef CONFIG_PM | |
255 | ||
256 | static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message) | |
257 | { | |
258 | ks8695_wdt_stop(); | |
259 | return 0; | |
260 | } | |
261 | ||
262 | static 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 | ||
274 | static 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 | ||
286 | static 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 | ||
297 | static void __exit ks8695_wdt_exit(void) | |
298 | { | |
299 | platform_driver_unregister(&ks8695wdt_driver); | |
300 | } | |
301 | ||
302 | module_init(ks8695_wdt_init); | |
303 | module_exit(ks8695_wdt_exit); | |
304 | ||
305 | MODULE_AUTHOR("Andrew Victor"); | |
306 | MODULE_DESCRIPTION("Watchdog driver for KS8695"); | |
307 | MODULE_LICENSE("GPL"); | |
308 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |