Commit | Line | Data |
---|---|---|
853807fb AV |
1 | /* |
2 | * Watchdog driver for Atmel AT91RM9200 (Thunder) | |
3 | * | |
4 | * Copyright (C) 2003 SAN People (Pty) Ltd | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
27c766aa JP |
12 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
13 | ||
1977f032 | 14 | #include <linux/bitops.h> |
9ab45f3f | 15 | #include <linux/delay.h> |
853807fb AV |
16 | #include <linux/errno.h> |
17 | #include <linux/fs.h> | |
18 | #include <linux/init.h> | |
02e0746e | 19 | #include <linux/io.h> |
853807fb | 20 | #include <linux/kernel.h> |
8432f9e5 AB |
21 | #include <linux/mfd/syscon.h> |
22 | #include <linux/mfd/syscon/atmel-st.h> | |
853807fb AV |
23 | #include <linux/miscdevice.h> |
24 | #include <linux/module.h> | |
25 | #include <linux/moduleparam.h> | |
dfc7bd9c | 26 | #include <linux/platform_device.h> |
9ab45f3f | 27 | #include <linux/reboot.h> |
8432f9e5 | 28 | #include <linux/regmap.h> |
853807fb AV |
29 | #include <linux/types.h> |
30 | #include <linux/watchdog.h> | |
2760600d | 31 | #include <linux/uaccess.h> |
a6a1bcd3 JE |
32 | #include <linux/of.h> |
33 | #include <linux/of_device.h> | |
853807fb | 34 | |
dfc7bd9c AV |
35 | #define WDT_DEFAULT_TIME 5 /* seconds */ |
36 | #define WDT_MAX_TIME 256 /* seconds */ | |
853807fb AV |
37 | |
38 | static int wdt_time = WDT_DEFAULT_TIME; | |
86a1e189 | 39 | static bool nowayout = WATCHDOG_NOWAYOUT; |
8432f9e5 | 40 | static struct regmap *regmap_st; |
853807fb AV |
41 | |
42 | module_param(wdt_time, int, 0); | |
2760600d AC |
43 | MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default=" |
44 | __MODULE_STRING(WDT_DEFAULT_TIME) ")"); | |
853807fb | 45 | |
dfc7bd9c | 46 | #ifdef CONFIG_WATCHDOG_NOWAYOUT |
86a1e189 | 47 | module_param(nowayout, bool, 0); |
2760600d AC |
48 | MODULE_PARM_DESC(nowayout, |
49 | "Watchdog cannot be stopped once started (default=" | |
50 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
dfc7bd9c | 51 | #endif |
853807fb AV |
52 | |
53 | ||
54 | static unsigned long at91wdt_busy; | |
55 | ||
56 | /* ......................................................................... */ | |
57 | ||
9ab45f3f AB |
58 | static int at91rm9200_restart(struct notifier_block *this, |
59 | unsigned long mode, void *cmd) | |
60 | { | |
61 | /* | |
62 | * Perform a hardware reset with the use of the Watchdog timer. | |
63 | */ | |
64 | regmap_write(regmap_st, AT91_ST_WDMR, | |
65 | AT91_ST_RSTEN | AT91_ST_EXTEN | 1); | |
66 | regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST); | |
67 | ||
68 | mdelay(2000); | |
69 | ||
70 | pr_emerg("Unable to restart system\n"); | |
71 | return NOTIFY_DONE; | |
72 | } | |
73 | ||
74 | static struct notifier_block at91rm9200_restart_nb = { | |
75 | .notifier_call = at91rm9200_restart, | |
76 | .priority = 192, | |
77 | }; | |
78 | ||
853807fb AV |
79 | /* |
80 | * Disable the watchdog. | |
81 | */ | |
2760600d | 82 | static inline void at91_wdt_stop(void) |
853807fb | 83 | { |
8432f9e5 | 84 | regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN); |
853807fb AV |
85 | } |
86 | ||
87 | /* | |
88 | * Enable and reset the watchdog. | |
89 | */ | |
2760600d | 90 | static inline void at91_wdt_start(void) |
853807fb | 91 | { |
8432f9e5 | 92 | regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN | |
2760600d | 93 | (((65536 * wdt_time) >> 8) & AT91_ST_WDV)); |
8432f9e5 | 94 | regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST); |
853807fb AV |
95 | } |
96 | ||
97 | /* | |
98 | * Reload the watchdog timer. (ie, pat the watchdog) | |
99 | */ | |
2760600d | 100 | static inline void at91_wdt_reload(void) |
853807fb | 101 | { |
8432f9e5 | 102 | regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST); |
853807fb AV |
103 | } |
104 | ||
105 | /* ......................................................................... */ | |
106 | ||
107 | /* | |
108 | * Watchdog device is opened, and watchdog starts running. | |
109 | */ | |
110 | static int at91_wdt_open(struct inode *inode, struct file *file) | |
111 | { | |
112 | if (test_and_set_bit(0, &at91wdt_busy)) | |
113 | return -EBUSY; | |
114 | ||
115 | at91_wdt_start(); | |
116 | return nonseekable_open(inode, file); | |
117 | } | |
118 | ||
119 | /* | |
120 | * Close the watchdog device. | |
121 | * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also | |
122 | * disabled. | |
123 | */ | |
124 | static int at91_wdt_close(struct inode *inode, struct file *file) | |
125 | { | |
2760600d | 126 | /* Disable the watchdog when file is closed */ |
853807fb | 127 | if (!nowayout) |
2760600d | 128 | at91_wdt_stop(); |
853807fb AV |
129 | |
130 | clear_bit(0, &at91wdt_busy); | |
131 | return 0; | |
132 | } | |
133 | ||
134 | /* | |
135 | * Change the watchdog time interval. | |
136 | */ | |
137 | static int at91_wdt_settimeout(int new_time) | |
138 | { | |
139 | /* | |
2af29b78 | 140 | * All counting occurs at SLOW_CLOCK / 128 = 256 Hz |
853807fb AV |
141 | * |
142 | * Since WDV is a 16-bit counter, the maximum period is | |
2af29b78 | 143 | * 65536 / 256 = 256 seconds. |
853807fb AV |
144 | */ |
145 | if ((new_time <= 0) || (new_time > WDT_MAX_TIME)) | |
146 | return -EINVAL; | |
147 | ||
2760600d AC |
148 | /* Set new watchdog time. It will be used when |
149 | at91_wdt_start() is called. */ | |
853807fb AV |
150 | wdt_time = new_time; |
151 | return 0; | |
152 | } | |
153 | ||
42747d71 | 154 | static const struct watchdog_info at91_wdt_info = { |
853807fb AV |
155 | .identity = "at91 watchdog", |
156 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, | |
157 | }; | |
158 | ||
159 | /* | |
160 | * Handle commands from user-space. | |
161 | */ | |
3c4fafd6 | 162 | static long at91_wdt_ioctl(struct file *file, |
2760600d | 163 | unsigned int cmd, unsigned long arg) |
853807fb AV |
164 | { |
165 | void __user *argp = (void __user *)arg; | |
166 | int __user *p = argp; | |
167 | int new_value; | |
168 | ||
2760600d | 169 | switch (cmd) { |
2760600d AC |
170 | case WDIOC_GETSUPPORT: |
171 | return copy_to_user(argp, &at91_wdt_info, | |
172 | sizeof(at91_wdt_info)) ? -EFAULT : 0; | |
2760600d AC |
173 | case WDIOC_GETSTATUS: |
174 | case WDIOC_GETBOOTSTATUS: | |
175 | return put_user(0, p); | |
176 | case WDIOC_SETOPTIONS: | |
177 | if (get_user(new_value, p)) | |
178 | return -EFAULT; | |
179 | if (new_value & WDIOS_DISABLECARD) | |
180 | at91_wdt_stop(); | |
181 | if (new_value & WDIOS_ENABLECARD) | |
853807fb | 182 | at91_wdt_start(); |
2760600d | 183 | return 0; |
0c06090c WVS |
184 | case WDIOC_KEEPALIVE: |
185 | at91_wdt_reload(); /* pat the watchdog */ | |
186 | return 0; | |
187 | case WDIOC_SETTIMEOUT: | |
188 | if (get_user(new_value, p)) | |
189 | return -EFAULT; | |
190 | if (at91_wdt_settimeout(new_value)) | |
191 | return -EINVAL; | |
192 | /* Enable new time value */ | |
193 | at91_wdt_start(); | |
194 | /* Return current value */ | |
195 | return put_user(wdt_time, p); | |
196 | case WDIOC_GETTIMEOUT: | |
197 | return put_user(wdt_time, p); | |
2760600d AC |
198 | default: |
199 | return -ENOTTY; | |
853807fb AV |
200 | } |
201 | } | |
202 | ||
203 | /* | |
204 | * Pat the watchdog whenever device is written to. | |
205 | */ | |
2760600d AC |
206 | static ssize_t at91_wdt_write(struct file *file, const char *data, |
207 | size_t len, loff_t *ppos) | |
853807fb AV |
208 | { |
209 | at91_wdt_reload(); /* pat the watchdog */ | |
210 | return len; | |
211 | } | |
212 | ||
213 | /* ......................................................................... */ | |
214 | ||
62322d25 | 215 | static const struct file_operations at91wdt_fops = { |
853807fb AV |
216 | .owner = THIS_MODULE, |
217 | .llseek = no_llseek, | |
2760600d | 218 | .unlocked_ioctl = at91_wdt_ioctl, |
853807fb AV |
219 | .open = at91_wdt_open, |
220 | .release = at91_wdt_close, | |
221 | .write = at91_wdt_write, | |
222 | }; | |
223 | ||
224 | static struct miscdevice at91wdt_miscdev = { | |
225 | .minor = WATCHDOG_MINOR, | |
226 | .name = "watchdog", | |
227 | .fops = &at91wdt_fops, | |
228 | }; | |
229 | ||
2d991a16 | 230 | static int at91wdt_probe(struct platform_device *pdev) |
853807fb | 231 | { |
8432f9e5 AB |
232 | struct device *dev = &pdev->dev; |
233 | struct device *parent; | |
853807fb AV |
234 | int res; |
235 | ||
e0b79e0b | 236 | if (at91wdt_miscdev.parent) |
dfc7bd9c | 237 | return -EBUSY; |
e0b79e0b | 238 | at91wdt_miscdev.parent = &pdev->dev; |
853807fb | 239 | |
8432f9e5 AB |
240 | parent = dev->parent; |
241 | if (!parent) { | |
242 | dev_err(dev, "no parent\n"); | |
243 | return -ENODEV; | |
244 | } | |
245 | ||
246 | regmap_st = syscon_node_to_regmap(parent->of_node); | |
bf5125d5 | 247 | if (IS_ERR(regmap_st)) |
8432f9e5 AB |
248 | return -ENODEV; |
249 | ||
853807fb AV |
250 | res = misc_register(&at91wdt_miscdev); |
251 | if (res) | |
252 | return res; | |
253 | ||
9ab45f3f AB |
254 | res = register_restart_handler(&at91rm9200_restart_nb); |
255 | if (res) | |
256 | dev_warn(dev, "failed to register restart handler\n"); | |
257 | ||
27c766aa JP |
258 | pr_info("AT91 Watchdog Timer enabled (%d seconds%s)\n", |
259 | wdt_time, nowayout ? ", nowayout" : ""); | |
853807fb AV |
260 | return 0; |
261 | } | |
262 | ||
4b12b896 | 263 | static int at91wdt_remove(struct platform_device *pdev) |
dfc7bd9c | 264 | { |
9ab45f3f | 265 | struct device *dev = &pdev->dev; |
dfc7bd9c AV |
266 | int res; |
267 | ||
9ab45f3f AB |
268 | res = unregister_restart_handler(&at91rm9200_restart_nb); |
269 | if (res) | |
270 | dev_warn(dev, "failed to unregister restart handler\n"); | |
271 | ||
f368ed60 GKH |
272 | misc_deregister(&at91wdt_miscdev); |
273 | at91wdt_miscdev.parent = NULL; | |
dfc7bd9c AV |
274 | |
275 | return res; | |
276 | } | |
277 | ||
278 | static void at91wdt_shutdown(struct platform_device *pdev) | |
279 | { | |
280 | at91_wdt_stop(); | |
281 | } | |
282 | ||
283 | #ifdef CONFIG_PM | |
284 | ||
285 | static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message) | |
286 | { | |
287 | at91_wdt_stop(); | |
288 | return 0; | |
289 | } | |
290 | ||
291 | static int at91wdt_resume(struct platform_device *pdev) | |
292 | { | |
293 | if (at91wdt_busy) | |
294 | at91_wdt_start(); | |
95f62bdc | 295 | return 0; |
dfc7bd9c AV |
296 | } |
297 | ||
298 | #else | |
299 | #define at91wdt_suspend NULL | |
300 | #define at91wdt_resume NULL | |
301 | #endif | |
302 | ||
a6a1bcd3 JE |
303 | static const struct of_device_id at91_wdt_dt_ids[] = { |
304 | { .compatible = "atmel,at91rm9200-wdt" }, | |
305 | { /* sentinel */ } | |
306 | }; | |
307 | MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids); | |
308 | ||
dfc7bd9c AV |
309 | static struct platform_driver at91wdt_driver = { |
310 | .probe = at91wdt_probe, | |
82268714 | 311 | .remove = at91wdt_remove, |
dfc7bd9c AV |
312 | .shutdown = at91wdt_shutdown, |
313 | .suspend = at91wdt_suspend, | |
314 | .resume = at91wdt_resume, | |
315 | .driver = { | |
8432f9e5 | 316 | .name = "atmel_st_watchdog", |
85eee819 | 317 | .of_match_table = at91_wdt_dt_ids, |
dfc7bd9c AV |
318 | }, |
319 | }; | |
320 | ||
321 | static int __init at91_wdt_init(void) | |
322 | { | |
2760600d AC |
323 | /* Check that the heartbeat value is within range; |
324 | if not reset to the default */ | |
dfc7bd9c AV |
325 | if (at91_wdt_settimeout(wdt_time)) { |
326 | at91_wdt_settimeout(WDT_DEFAULT_TIME); | |
27c766aa JP |
327 | pr_info("wdt_time value must be 1 <= wdt_time <= 256, using %d\n", |
328 | wdt_time); | |
dfc7bd9c AV |
329 | } |
330 | ||
331 | return platform_driver_register(&at91wdt_driver); | |
332 | } | |
333 | ||
853807fb AV |
334 | static void __exit at91_wdt_exit(void) |
335 | { | |
dfc7bd9c | 336 | platform_driver_unregister(&at91wdt_driver); |
853807fb AV |
337 | } |
338 | ||
339 | module_init(at91_wdt_init); | |
340 | module_exit(at91_wdt_exit); | |
341 | ||
342 | MODULE_AUTHOR("Andrew Victor"); | |
343 | MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200"); | |
344 | MODULE_LICENSE("GPL"); | |
8432f9e5 | 345 | MODULE_ALIAS("platform:atmel_st_watchdog"); |