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0b36086b JC |
1 | /* Watchdog timer for the Geode GX/LX with the CS5535/CS5536 companion chip |
2 | * | |
3 | * Copyright (C) 2006-2007, Advanced Micro Devices, Inc. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU General Public License | |
7 | * as published by the Free Software Foundation; either version | |
8 | * 2 of the License, or (at your option) any later version. | |
9 | */ | |
10 | ||
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/moduleparam.h> | |
14 | #include <linux/types.h> | |
15 | #include <linux/miscdevice.h> | |
16 | #include <linux/watchdog.h> | |
17 | #include <linux/fs.h> | |
18 | #include <linux/platform_device.h> | |
19 | #include <linux/reboot.h> | |
089ab079 | 20 | #include <linux/uaccess.h> |
0b36086b | 21 | |
0b36086b JC |
22 | #include <asm/geode.h> |
23 | ||
24 | #define GEODEWDT_HZ 500 | |
25 | #define GEODEWDT_SCALE 6 | |
26 | #define GEODEWDT_MAX_SECONDS 131 | |
27 | ||
28 | #define WDT_FLAGS_OPEN 1 | |
29 | #define WDT_FLAGS_ORPHAN 2 | |
30 | ||
31 | #define DRV_NAME "geodewdt" | |
32 | #define WATCHDOG_NAME "Geode GX/LX WDT" | |
33 | #define WATCHDOG_TIMEOUT 60 | |
34 | ||
35 | static int timeout = WATCHDOG_TIMEOUT; | |
36 | module_param(timeout, int, 0); | |
143a2e54 WVS |
37 | MODULE_PARM_DESC(timeout, |
38 | "Watchdog timeout in seconds. 1<= timeout <=131, default=" | |
39 | __MODULE_STRING(WATCHDOG_TIMEOUT) "."); | |
0b36086b JC |
40 | |
41 | static int nowayout = WATCHDOG_NOWAYOUT; | |
42 | module_param(nowayout, int, 0); | |
143a2e54 WVS |
43 | MODULE_PARM_DESC(nowayout, |
44 | "Watchdog cannot be stopped once started (default=" | |
45 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
0b36086b JC |
46 | |
47 | static struct platform_device *geodewdt_platform_device; | |
48 | static unsigned long wdt_flags; | |
49 | static int wdt_timer; | |
50 | static int safe_close; | |
51 | ||
52 | static void geodewdt_ping(void) | |
53 | { | |
54 | /* Stop the counter */ | |
55 | geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0); | |
56 | ||
57 | /* Reset the counter */ | |
58 | geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0); | |
59 | ||
60 | /* Enable the counter */ | |
61 | geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN); | |
62 | } | |
63 | ||
64 | static void geodewdt_disable(void) | |
65 | { | |
66 | geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0); | |
67 | geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0); | |
68 | } | |
69 | ||
70 | static int geodewdt_set_heartbeat(int val) | |
71 | { | |
72 | if (val < 1 || val > GEODEWDT_MAX_SECONDS) | |
73 | return -EINVAL; | |
74 | ||
75 | geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0); | |
76 | geode_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ); | |
77 | geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0); | |
78 | geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN); | |
79 | ||
80 | timeout = val; | |
81 | return 0; | |
82 | } | |
83 | ||
7944d3a5 | 84 | static int geodewdt_open(struct inode *inode, struct file *file) |
0b36086b | 85 | { |
7944d3a5 WVS |
86 | if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags)) |
87 | return -EBUSY; | |
0b36086b | 88 | |
7944d3a5 WVS |
89 | if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags)) |
90 | __module_get(THIS_MODULE); | |
0b36086b JC |
91 | |
92 | geodewdt_ping(); | |
7944d3a5 | 93 | return nonseekable_open(inode, file); |
0b36086b JC |
94 | } |
95 | ||
7944d3a5 | 96 | static int geodewdt_release(struct inode *inode, struct file *file) |
0b36086b JC |
97 | { |
98 | if (safe_close) { | |
99 | geodewdt_disable(); | |
100 | module_put(THIS_MODULE); | |
7944d3a5 | 101 | } else { |
0b36086b JC |
102 | printk(KERN_CRIT "Unexpected close - watchdog is not stopping.\n"); |
103 | geodewdt_ping(); | |
104 | ||
105 | set_bit(WDT_FLAGS_ORPHAN, &wdt_flags); | |
106 | } | |
107 | ||
108 | clear_bit(WDT_FLAGS_OPEN, &wdt_flags); | |
109 | safe_close = 0; | |
110 | return 0; | |
111 | } | |
112 | ||
7944d3a5 WVS |
113 | static ssize_t geodewdt_write(struct file *file, const char __user *data, |
114 | size_t len, loff_t *ppos) | |
0b36086b | 115 | { |
7944d3a5 | 116 | if (len) { |
0b36086b JC |
117 | if (!nowayout) { |
118 | size_t i; | |
119 | safe_close = 0; | |
120 | ||
121 | for (i = 0; i != len; i++) { | |
122 | char c; | |
123 | ||
124 | if (get_user(c, data + i)) | |
125 | return -EFAULT; | |
126 | ||
127 | if (c == 'V') | |
128 | safe_close = 1; | |
129 | } | |
130 | } | |
131 | ||
132 | geodewdt_ping(); | |
133 | } | |
134 | return len; | |
135 | } | |
136 | ||
7275fc8c WVS |
137 | static long geodewdt_ioctl(struct file *file, unsigned int cmd, |
138 | unsigned long arg) | |
0b36086b JC |
139 | { |
140 | void __user *argp = (void __user *)arg; | |
141 | int __user *p = argp; | |
142 | int interval; | |
143 | ||
144 | static struct watchdog_info ident = { | |
145 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | |
146 | | WDIOF_MAGICCLOSE, | |
147 | .firmware_version = 1, | |
148 | .identity = WATCHDOG_NAME, | |
7944d3a5 | 149 | }; |
0b36086b | 150 | |
5eb82498 | 151 | switch (cmd) { |
0b36086b JC |
152 | case WDIOC_GETSUPPORT: |
153 | return copy_to_user(argp, &ident, | |
154 | sizeof(ident)) ? -EFAULT : 0; | |
155 | break; | |
156 | ||
157 | case WDIOC_GETSTATUS: | |
158 | case WDIOC_GETBOOTSTATUS: | |
159 | return put_user(0, p); | |
160 | ||
0b36086b JC |
161 | case WDIOC_SETOPTIONS: |
162 | { | |
163 | int options, ret = -EINVAL; | |
164 | ||
165 | if (get_user(options, p)) | |
166 | return -EFAULT; | |
167 | ||
168 | if (options & WDIOS_DISABLECARD) { | |
169 | geodewdt_disable(); | |
170 | ret = 0; | |
171 | } | |
172 | ||
173 | if (options & WDIOS_ENABLECARD) { | |
174 | geodewdt_ping(); | |
175 | ret = 0; | |
176 | } | |
177 | ||
178 | return ret; | |
179 | } | |
0c06090c WVS |
180 | case WDIOC_KEEPALIVE: |
181 | geodewdt_ping(); | |
182 | return 0; | |
183 | ||
184 | case WDIOC_SETTIMEOUT: | |
185 | if (get_user(interval, p)) | |
186 | return -EFAULT; | |
187 | ||
188 | if (geodewdt_set_heartbeat(interval)) | |
189 | return -EINVAL; | |
190 | /* Fall through */ | |
191 | case WDIOC_GETTIMEOUT: | |
192 | return put_user(timeout, p); | |
193 | ||
0b36086b JC |
194 | default: |
195 | return -ENOTTY; | |
196 | } | |
197 | ||
198 | return 0; | |
199 | } | |
200 | ||
201 | static const struct file_operations geodewdt_fops = { | |
7944d3a5 WVS |
202 | .owner = THIS_MODULE, |
203 | .llseek = no_llseek, | |
204 | .write = geodewdt_write, | |
7275fc8c | 205 | .unlocked_ioctl = geodewdt_ioctl, |
7944d3a5 WVS |
206 | .open = geodewdt_open, |
207 | .release = geodewdt_release, | |
0b36086b JC |
208 | }; |
209 | ||
210 | static struct miscdevice geodewdt_miscdev = { | |
211 | .minor = WATCHDOG_MINOR, | |
212 | .name = "watchdog", | |
7944d3a5 | 213 | .fops = &geodewdt_fops, |
0b36086b JC |
214 | }; |
215 | ||
7944d3a5 | 216 | static int __devinit geodewdt_probe(struct platform_device *dev) |
0b36086b JC |
217 | { |
218 | int ret, timer; | |
219 | ||
57f50ca1 | 220 | timer = geode_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING); |
0b36086b JC |
221 | |
222 | if (timer == -1) { | |
223 | printk(KERN_ERR "geodewdt: No timers were available\n"); | |
224 | return -ENODEV; | |
225 | } | |
226 | ||
227 | wdt_timer = timer; | |
228 | ||
229 | /* Set up the timer */ | |
230 | ||
231 | geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, | |
232 | GEODEWDT_SCALE | (3 << 8)); | |
233 | ||
234 | /* Set up comparator 2 to reset when the event fires */ | |
235 | geode_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1); | |
236 | ||
237 | /* Set up the initial timeout */ | |
238 | ||
239 | geode_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, | |
240 | timeout * GEODEWDT_HZ); | |
241 | ||
242 | ret = misc_register(&geodewdt_miscdev); | |
243 | ||
244 | return ret; | |
245 | } | |
246 | ||
7944d3a5 | 247 | static int __devexit geodewdt_remove(struct platform_device *dev) |
0b36086b JC |
248 | { |
249 | misc_deregister(&geodewdt_miscdev); | |
250 | return 0; | |
251 | } | |
252 | ||
7944d3a5 | 253 | static void geodewdt_shutdown(struct platform_device *dev) |
0b36086b JC |
254 | { |
255 | geodewdt_disable(); | |
256 | } | |
257 | ||
258 | static struct platform_driver geodewdt_driver = { | |
259 | .probe = geodewdt_probe, | |
260 | .remove = __devexit_p(geodewdt_remove), | |
261 | .shutdown = geodewdt_shutdown, | |
262 | .driver = { | |
263 | .owner = THIS_MODULE, | |
264 | .name = DRV_NAME, | |
265 | }, | |
266 | }; | |
267 | ||
7944d3a5 | 268 | static int __init geodewdt_init(void) |
0b36086b JC |
269 | { |
270 | int ret; | |
271 | ||
272 | ret = platform_driver_register(&geodewdt_driver); | |
273 | if (ret) | |
274 | return ret; | |
275 | ||
143a2e54 WVS |
276 | geodewdt_platform_device = platform_device_register_simple(DRV_NAME, |
277 | -1, NULL, 0); | |
0b36086b JC |
278 | if (IS_ERR(geodewdt_platform_device)) { |
279 | ret = PTR_ERR(geodewdt_platform_device); | |
280 | goto err; | |
281 | } | |
282 | ||
283 | return 0; | |
284 | err: | |
285 | platform_driver_unregister(&geodewdt_driver); | |
286 | return ret; | |
287 | } | |
288 | ||
7944d3a5 | 289 | static void __exit geodewdt_exit(void) |
0b36086b JC |
290 | { |
291 | platform_device_unregister(geodewdt_platform_device); | |
292 | platform_driver_unregister(&geodewdt_driver); | |
293 | } | |
294 | ||
295 | module_init(geodewdt_init); | |
296 | module_exit(geodewdt_exit); | |
297 | ||
298 | MODULE_AUTHOR("Advanced Micro Devices, Inc"); | |
299 | MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver"); | |
300 | MODULE_LICENSE("GPL"); | |
301 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |