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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 | ||
27c766aa JP |
11 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
12 | ||
1977f032 | 13 | #include <linux/bitops.h> |
ccb8f430 AV |
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> | |
f4fabce1 AC |
24 | #include <linux/io.h> |
25 | #include <linux/uaccess.h> | |
568dba66 | 26 | #include <mach/hardware.h> |
cab463a2 LW |
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 */ | |
ccb8f430 | 40 | |
ccb8f430 AV |
41 | #define WDT_DEFAULT_TIME 5 /* seconds */ |
42 | #define WDT_MAX_TIME 171 /* seconds */ | |
43 | ||
44 | static int wdt_time = WDT_DEFAULT_TIME; | |
86a1e189 | 45 | static bool nowayout = WATCHDOG_NOWAYOUT; |
ccb8f430 AV |
46 | |
47 | module_param(wdt_time, int, 0); | |
f4fabce1 AC |
48 | MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default=" |
49 | __MODULE_STRING(WDT_DEFAULT_TIME) ")"); | |
ccb8f430 AV |
50 | |
51 | #ifdef CONFIG_WATCHDOG_NOWAYOUT | |
86a1e189 | 52 | module_param(nowayout, bool, 0); |
f4fabce1 AC |
53 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
54 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
ccb8f430 AV |
55 | #endif |
56 | ||
57 | ||
58 | static unsigned long ks8695wdt_busy; | |
1334f329 | 59 | static DEFINE_SPINLOCK(ks8695_lock); |
ccb8f430 AV |
60 | |
61 | /* ......................................................................... */ | |
62 | ||
63 | /* | |
64 | * Disable the watchdog. | |
65 | */ | |
f4fabce1 | 66 | static inline void ks8695_wdt_stop(void) |
ccb8f430 AV |
67 | { |
68 | unsigned long tmcon; | |
69 | ||
f4fabce1 | 70 | spin_lock(&ks8695_lock); |
ccb8f430 AV |
71 | /* disable timer0 */ |
72 | tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON); | |
73 | __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON); | |
f4fabce1 | 74 | spin_unlock(&ks8695_lock); |
ccb8f430 AV |
75 | } |
76 | ||
77 | /* | |
78 | * Enable and reset the watchdog. | |
79 | */ | |
f4fabce1 | 80 | static inline void ks8695_wdt_start(void) |
ccb8f430 AV |
81 | { |
82 | unsigned long tmcon; | |
0a51810a | 83 | unsigned long tval = wdt_time * KS8695_CLOCK_RATE; |
ccb8f430 | 84 | |
f4fabce1 | 85 | spin_lock(&ks8695_lock); |
ccb8f430 AV |
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); | |
f4fabce1 | 96 | spin_unlock(&ks8695_lock); |
ccb8f430 AV |
97 | } |
98 | ||
99 | /* | |
100 | * Reload the watchdog timer. (ie, pat the watchdog) | |
101 | */ | |
f4fabce1 | 102 | static inline void ks8695_wdt_reload(void) |
ccb8f430 AV |
103 | { |
104 | unsigned long tmcon; | |
105 | ||
f4fabce1 | 106 | spin_lock(&ks8695_lock); |
ccb8f430 AV |
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); | |
f4fabce1 | 111 | spin_unlock(&ks8695_lock); |
ccb8f430 AV |
112 | } |
113 | ||
114 | /* | |
115 | * Change the watchdog time interval. | |
116 | */ | |
117 | static int ks8695_wdt_settimeout(int new_time) | |
118 | { | |
119 | /* | |
0a51810a | 120 | * All counting occurs at KS8695_CLOCK_RATE / 128 = 0.256 Hz |
ccb8f430 AV |
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 | ||
f4fabce1 AC |
128 | /* Set new watchdog time. It will be used when |
129 | ks8695_wdt_start() is called. */ | |
ccb8f430 AV |
130 | wdt_time = new_time; |
131 | return 0; | |
132 | } | |
133 | ||
134 | /* ......................................................................... */ | |
135 | ||
136 | /* | |
137 | * Watchdog device is opened, and watchdog starts running. | |
138 | */ | |
139 | static 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 | */ | |
153 | static int ks8695_wdt_close(struct inode *inode, struct file *file) | |
154 | { | |
f4fabce1 | 155 | /* Disable the watchdog when file is closed */ |
ccb8f430 | 156 | if (!nowayout) |
f4fabce1 | 157 | ks8695_wdt_stop(); |
ccb8f430 AV |
158 | clear_bit(0, &ks8695wdt_busy); |
159 | return 0; | |
160 | } | |
161 | ||
42747d71 | 162 | static const struct watchdog_info ks8695_wdt_info = { |
ccb8f430 AV |
163 | .identity = "ks8695 watchdog", |
164 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, | |
165 | }; | |
166 | ||
167 | /* | |
168 | * Handle commands from user-space. | |
169 | */ | |
f4fabce1 AC |
170 | static long ks8695_wdt_ioctl(struct file *file, unsigned int cmd, |
171 | unsigned long arg) | |
ccb8f430 AV |
172 | { |
173 | void __user *argp = (void __user *)arg; | |
174 | int __user *p = argp; | |
175 | int new_value; | |
176 | ||
f4fabce1 | 177 | switch (cmd) { |
f4fabce1 AC |
178 | case WDIOC_GETSUPPORT: |
179 | return copy_to_user(argp, &ks8695_wdt_info, | |
180 | sizeof(ks8695_wdt_info)) ? -EFAULT : 0; | |
f4fabce1 AC |
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) | |
ccb8f430 | 190 | ks8695_wdt_start(); |
f4fabce1 | 191 | return 0; |
0c06090c WVS |
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); | |
f4fabce1 AC |
206 | default: |
207 | return -ENOTTY; | |
ccb8f430 AV |
208 | } |
209 | } | |
210 | ||
211 | /* | |
212 | * Pat the watchdog whenever device is written to. | |
213 | */ | |
f4fabce1 AC |
214 | static ssize_t ks8695_wdt_write(struct file *file, const char *data, |
215 | size_t len, loff_t *ppos) | |
ccb8f430 AV |
216 | { |
217 | ks8695_wdt_reload(); /* pat the watchdog */ | |
218 | return len; | |
219 | } | |
220 | ||
221 | /* ......................................................................... */ | |
222 | ||
223 | static const struct file_operations ks8695wdt_fops = { | |
224 | .owner = THIS_MODULE, | |
225 | .llseek = no_llseek, | |
f4fabce1 | 226 | .unlocked_ioctl = ks8695_wdt_ioctl, |
ccb8f430 AV |
227 | .open = ks8695_wdt_open, |
228 | .release = ks8695_wdt_close, | |
229 | .write = ks8695_wdt_write, | |
230 | }; | |
231 | ||
232 | static struct miscdevice ks8695wdt_miscdev = { | |
233 | .minor = WATCHDOG_MINOR, | |
234 | .name = "watchdog", | |
235 | .fops = &ks8695wdt_fops, | |
236 | }; | |
237 | ||
2d991a16 | 238 | static int ks8695wdt_probe(struct platform_device *pdev) |
ccb8f430 AV |
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 | ||
27c766aa JP |
250 | pr_info("KS8695 Watchdog Timer enabled (%d seconds%s)\n", |
251 | wdt_time, nowayout ? ", nowayout" : ""); | |
ccb8f430 AV |
252 | return 0; |
253 | } | |
254 | ||
4b12b896 | 255 | static int ks8695wdt_remove(struct platform_device *pdev) |
ccb8f430 AV |
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 | ||
266 | static void ks8695wdt_shutdown(struct platform_device *pdev) | |
267 | { | |
268 | ks8695_wdt_stop(); | |
269 | } | |
270 | ||
271 | #ifdef CONFIG_PM | |
272 | ||
273 | static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message) | |
274 | { | |
275 | ks8695_wdt_stop(); | |
276 | return 0; | |
277 | } | |
278 | ||
279 | static 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 | ||
291 | static struct platform_driver ks8695wdt_driver = { | |
292 | .probe = ks8695wdt_probe, | |
82268714 | 293 | .remove = ks8695wdt_remove, |
ccb8f430 AV |
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 | ||
303 | static int __init ks8695_wdt_init(void) | |
304 | { | |
f4fabce1 AC |
305 | /* Check that the heartbeat value is within range; |
306 | if not reset to the default */ | |
ccb8f430 AV |
307 | if (ks8695_wdt_settimeout(wdt_time)) { |
308 | ks8695_wdt_settimeout(WDT_DEFAULT_TIME); | |
a77dba7e WVS |
309 | pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i" |
310 | ", using %d\n", wdt_time, WDT_MAX_TIME); | |
ccb8f430 | 311 | } |
ccb8f430 AV |
312 | return platform_driver_register(&ks8695wdt_driver); |
313 | } | |
314 | ||
315 | static void __exit ks8695_wdt_exit(void) | |
316 | { | |
317 | platform_driver_unregister(&ks8695wdt_driver); | |
318 | } | |
319 | ||
320 | module_init(ks8695_wdt_init); | |
321 | module_exit(ks8695_wdt_exit); | |
322 | ||
323 | MODULE_AUTHOR("Andrew Victor"); | |
324 | MODULE_DESCRIPTION("Watchdog driver for KS8695"); | |
325 | MODULE_LICENSE("GPL"); | |
326 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
f37d193c | 327 | MODULE_ALIAS("platform:ks8695_wdt"); |