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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Watchdog driver for Atmel AT91RM9200 (Thunder)
4 *
5 * Copyright (C) 2003 SAN People (Pty) Ltd
6 *
7 */
8
9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11#include <linux/bitops.h>
12#include <linux/delay.h>
13#include <linux/errno.h>
14#include <linux/fs.h>
15#include <linux/init.h>
16#include <linux/io.h>
17#include <linux/kernel.h>
18#include <linux/mfd/syscon.h>
19#include <linux/mfd/syscon/atmel-st.h>
20#include <linux/miscdevice.h>
21#include <linux/mod_devicetable.h>
22#include <linux/module.h>
23#include <linux/moduleparam.h>
24#include <linux/platform_device.h>
25#include <linux/reboot.h>
26#include <linux/regmap.h>
27#include <linux/types.h>
28#include <linux/watchdog.h>
29#include <linux/uaccess.h>
30
31#define WDT_DEFAULT_TIME 5 /* seconds */
32#define WDT_MAX_TIME 256 /* seconds */
33
34static int wdt_time = WDT_DEFAULT_TIME;
35static bool nowayout = WATCHDOG_NOWAYOUT;
36static struct regmap *regmap_st;
37
38module_param(wdt_time, int, 0);
39MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
40 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
41
42#ifdef CONFIG_WATCHDOG_NOWAYOUT
43module_param(nowayout, bool, 0);
44MODULE_PARM_DESC(nowayout,
45 "Watchdog cannot be stopped once started (default="
46 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
47#endif
48
49
50static unsigned long at91wdt_busy;
51
52/* ......................................................................... */
53
54static int at91rm9200_restart(struct notifier_block *this,
55 unsigned long mode, void *cmd)
56{
57 /*
58 * Perform a hardware reset with the use of the Watchdog timer.
59 */
60 regmap_write(regmap_st, AT91_ST_WDMR,
61 AT91_ST_RSTEN | AT91_ST_EXTEN | 1);
62 regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
63
64 mdelay(2000);
65
66 pr_emerg("Unable to restart system\n");
67 return NOTIFY_DONE;
68}
69
70static struct notifier_block at91rm9200_restart_nb = {
71 .notifier_call = at91rm9200_restart,
72 .priority = 192,
73};
74
75/*
76 * Disable the watchdog.
77 */
78static inline void at91_wdt_stop(void)
79{
80 regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN);
81}
82
83/*
84 * Enable and reset the watchdog.
85 */
86static inline void at91_wdt_start(void)
87{
88 regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN |
89 (((65536 * wdt_time) >> 8) & AT91_ST_WDV));
90 regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
91}
92
93/*
94 * Reload the watchdog timer. (ie, pat the watchdog)
95 */
96static inline void at91_wdt_reload(void)
97{
98 regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
99}
100
101/* ......................................................................... */
102
103/*
104 * Watchdog device is opened, and watchdog starts running.
105 */
106static int at91_wdt_open(struct inode *inode, struct file *file)
107{
108 if (test_and_set_bit(0, &at91wdt_busy))
109 return -EBUSY;
110
111 at91_wdt_start();
112 return stream_open(inode, file);
113}
114
115/*
116 * Close the watchdog device.
117 * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
118 * disabled.
119 */
120static int at91_wdt_close(struct inode *inode, struct file *file)
121{
122 /* Disable the watchdog when file is closed */
123 if (!nowayout)
124 at91_wdt_stop();
125
126 clear_bit(0, &at91wdt_busy);
127 return 0;
128}
129
130/*
131 * Change the watchdog time interval.
132 */
133static int at91_wdt_settimeout(int new_time)
134{
135 /*
136 * All counting occurs at SLOW_CLOCK / 128 = 256 Hz
137 *
138 * Since WDV is a 16-bit counter, the maximum period is
139 * 65536 / 256 = 256 seconds.
140 */
141 if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
142 return -EINVAL;
143
144 /* Set new watchdog time. It will be used when
145 at91_wdt_start() is called. */
146 wdt_time = new_time;
147 return 0;
148}
149
150static const struct watchdog_info at91_wdt_info = {
151 .identity = "at91 watchdog",
152 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
153};
154
155/*
156 * Handle commands from user-space.
157 */
158static long at91_wdt_ioctl(struct file *file,
159 unsigned int cmd, unsigned long arg)
160{
161 void __user *argp = (void __user *)arg;
162 int __user *p = argp;
163 int new_value;
164
165 switch (cmd) {
166 case WDIOC_GETSUPPORT:
167 return copy_to_user(argp, &at91_wdt_info,
168 sizeof(at91_wdt_info)) ? -EFAULT : 0;
169 case WDIOC_GETSTATUS:
170 case WDIOC_GETBOOTSTATUS:
171 return put_user(0, p);
172 case WDIOC_SETOPTIONS:
173 if (get_user(new_value, p))
174 return -EFAULT;
175 if (new_value & WDIOS_DISABLECARD)
176 at91_wdt_stop();
177 if (new_value & WDIOS_ENABLECARD)
178 at91_wdt_start();
179 return 0;
180 case WDIOC_KEEPALIVE:
181 at91_wdt_reload(); /* pat the watchdog */
182 return 0;
183 case WDIOC_SETTIMEOUT:
184 if (get_user(new_value, p))
185 return -EFAULT;
186 if (at91_wdt_settimeout(new_value))
187 return -EINVAL;
188 /* Enable new time value */
189 at91_wdt_start();
190 /* Return current value */
191 return put_user(wdt_time, p);
192 case WDIOC_GETTIMEOUT:
193 return put_user(wdt_time, p);
194 default:
195 return -ENOTTY;
196 }
197}
198
199/*
200 * Pat the watchdog whenever device is written to.
201 */
202static ssize_t at91_wdt_write(struct file *file, const char *data,
203 size_t len, loff_t *ppos)
204{
205 at91_wdt_reload(); /* pat the watchdog */
206 return len;
207}
208
209/* ......................................................................... */
210
211static const struct file_operations at91wdt_fops = {
212 .owner = THIS_MODULE,
213 .llseek = no_llseek,
214 .unlocked_ioctl = at91_wdt_ioctl,
215 .compat_ioctl = compat_ptr_ioctl,
216 .open = at91_wdt_open,
217 .release = at91_wdt_close,
218 .write = at91_wdt_write,
219};
220
221static struct miscdevice at91wdt_miscdev = {
222 .minor = WATCHDOG_MINOR,
223 .name = "watchdog",
224 .fops = &at91wdt_fops,
225};
226
227static int at91wdt_probe(struct platform_device *pdev)
228{
229 struct device *dev = &pdev->dev;
230 struct device *parent;
231 int res;
232
233 if (at91wdt_miscdev.parent)
234 return -EBUSY;
235 at91wdt_miscdev.parent = &pdev->dev;
236
237 parent = dev->parent;
238 if (!parent) {
239 dev_err(dev, "no parent\n");
240 return -ENODEV;
241 }
242
243 regmap_st = syscon_node_to_regmap(parent->of_node);
244 if (IS_ERR(regmap_st))
245 return -ENODEV;
246
247 res = misc_register(&at91wdt_miscdev);
248 if (res)
249 return res;
250
251 res = register_restart_handler(&at91rm9200_restart_nb);
252 if (res)
253 dev_warn(dev, "failed to register restart handler\n");
254
255 pr_info("AT91 Watchdog Timer enabled (%d seconds%s)\n",
256 wdt_time, nowayout ? ", nowayout" : "");
257 return 0;
258}
259
260static void at91wdt_remove(struct platform_device *pdev)
261{
262 struct device *dev = &pdev->dev;
263 int res;
264
265 res = unregister_restart_handler(&at91rm9200_restart_nb);
266 if (res)
267 dev_warn(dev, "failed to unregister restart handler\n");
268
269 misc_deregister(&at91wdt_miscdev);
270 at91wdt_miscdev.parent = NULL;
271}
272
273static void at91wdt_shutdown(struct platform_device *pdev)
274{
275 at91_wdt_stop();
276}
277
278static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message)
279{
280 at91_wdt_stop();
281 return 0;
282}
283
284static int at91wdt_resume(struct platform_device *pdev)
285{
286 if (at91wdt_busy)
287 at91_wdt_start();
288 return 0;
289}
290
291static const struct of_device_id at91_wdt_dt_ids[] = {
292 { .compatible = "atmel,at91rm9200-wdt" },
293 { /* sentinel */ }
294};
295MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);
296
297static struct platform_driver at91wdt_driver = {
298 .probe = at91wdt_probe,
299 .remove_new = at91wdt_remove,
300 .shutdown = at91wdt_shutdown,
301 .suspend = pm_ptr(at91wdt_suspend),
302 .resume = pm_ptr(at91wdt_resume),
303 .driver = {
304 .name = "atmel_st_watchdog",
305 .of_match_table = at91_wdt_dt_ids,
306 },
307};
308
309static int __init at91_wdt_init(void)
310{
311 /* Check that the heartbeat value is within range;
312 if not reset to the default */
313 if (at91_wdt_settimeout(wdt_time)) {
314 at91_wdt_settimeout(WDT_DEFAULT_TIME);
315 pr_info("wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
316 wdt_time);
317 }
318
319 return platform_driver_register(&at91wdt_driver);
320}
321
322static void __exit at91_wdt_exit(void)
323{
324 platform_driver_unregister(&at91wdt_driver);
325}
326
327module_init(at91_wdt_init);
328module_exit(at91_wdt_exit);
329
330MODULE_AUTHOR("Andrew Victor");
331MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
332MODULE_LICENSE("GPL");
333MODULE_ALIAS("platform:atmel_st_watchdog");
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
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/bitops.h>
15#include <linux/delay.h>
16#include <linux/errno.h>
17#include <linux/fs.h>
18#include <linux/init.h>
19#include <linux/io.h>
20#include <linux/kernel.h>
21#include <linux/mfd/syscon.h>
22#include <linux/mfd/syscon/atmel-st.h>
23#include <linux/miscdevice.h>
24#include <linux/module.h>
25#include <linux/moduleparam.h>
26#include <linux/platform_device.h>
27#include <linux/reboot.h>
28#include <linux/regmap.h>
29#include <linux/types.h>
30#include <linux/watchdog.h>
31#include <linux/uaccess.h>
32#include <linux/of.h>
33#include <linux/of_device.h>
34
35#define WDT_DEFAULT_TIME 5 /* seconds */
36#define WDT_MAX_TIME 256 /* seconds */
37
38static int wdt_time = WDT_DEFAULT_TIME;
39static bool nowayout = WATCHDOG_NOWAYOUT;
40static struct regmap *regmap_st;
41
42module_param(wdt_time, int, 0);
43MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
44 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
45
46#ifdef CONFIG_WATCHDOG_NOWAYOUT
47module_param(nowayout, bool, 0);
48MODULE_PARM_DESC(nowayout,
49 "Watchdog cannot be stopped once started (default="
50 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
51#endif
52
53
54static unsigned long at91wdt_busy;
55
56/* ......................................................................... */
57
58static 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
74static struct notifier_block at91rm9200_restart_nb = {
75 .notifier_call = at91rm9200_restart,
76 .priority = 192,
77};
78
79/*
80 * Disable the watchdog.
81 */
82static inline void at91_wdt_stop(void)
83{
84 regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN);
85}
86
87/*
88 * Enable and reset the watchdog.
89 */
90static inline void at91_wdt_start(void)
91{
92 regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN |
93 (((65536 * wdt_time) >> 8) & AT91_ST_WDV));
94 regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
95}
96
97/*
98 * Reload the watchdog timer. (ie, pat the watchdog)
99 */
100static inline void at91_wdt_reload(void)
101{
102 regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
103}
104
105/* ......................................................................... */
106
107/*
108 * Watchdog device is opened, and watchdog starts running.
109 */
110static 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 */
124static int at91_wdt_close(struct inode *inode, struct file *file)
125{
126 /* Disable the watchdog when file is closed */
127 if (!nowayout)
128 at91_wdt_stop();
129
130 clear_bit(0, &at91wdt_busy);
131 return 0;
132}
133
134/*
135 * Change the watchdog time interval.
136 */
137static int at91_wdt_settimeout(int new_time)
138{
139 /*
140 * All counting occurs at SLOW_CLOCK / 128 = 256 Hz
141 *
142 * Since WDV is a 16-bit counter, the maximum period is
143 * 65536 / 256 = 256 seconds.
144 */
145 if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
146 return -EINVAL;
147
148 /* Set new watchdog time. It will be used when
149 at91_wdt_start() is called. */
150 wdt_time = new_time;
151 return 0;
152}
153
154static const struct watchdog_info at91_wdt_info = {
155 .identity = "at91 watchdog",
156 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
157};
158
159/*
160 * Handle commands from user-space.
161 */
162static long at91_wdt_ioctl(struct file *file,
163 unsigned int cmd, unsigned long arg)
164{
165 void __user *argp = (void __user *)arg;
166 int __user *p = argp;
167 int new_value;
168
169 switch (cmd) {
170 case WDIOC_GETSUPPORT:
171 return copy_to_user(argp, &at91_wdt_info,
172 sizeof(at91_wdt_info)) ? -EFAULT : 0;
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)
182 at91_wdt_start();
183 return 0;
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);
198 default:
199 return -ENOTTY;
200 }
201}
202
203/*
204 * Pat the watchdog whenever device is written to.
205 */
206static ssize_t at91_wdt_write(struct file *file, const char *data,
207 size_t len, loff_t *ppos)
208{
209 at91_wdt_reload(); /* pat the watchdog */
210 return len;
211}
212
213/* ......................................................................... */
214
215static const struct file_operations at91wdt_fops = {
216 .owner = THIS_MODULE,
217 .llseek = no_llseek,
218 .unlocked_ioctl = at91_wdt_ioctl,
219 .open = at91_wdt_open,
220 .release = at91_wdt_close,
221 .write = at91_wdt_write,
222};
223
224static struct miscdevice at91wdt_miscdev = {
225 .minor = WATCHDOG_MINOR,
226 .name = "watchdog",
227 .fops = &at91wdt_fops,
228};
229
230static int at91wdt_probe(struct platform_device *pdev)
231{
232 struct device *dev = &pdev->dev;
233 struct device *parent;
234 int res;
235
236 if (at91wdt_miscdev.parent)
237 return -EBUSY;
238 at91wdt_miscdev.parent = &pdev->dev;
239
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);
247 if (IS_ERR(regmap_st))
248 return -ENODEV;
249
250 res = misc_register(&at91wdt_miscdev);
251 if (res)
252 return res;
253
254 res = register_restart_handler(&at91rm9200_restart_nb);
255 if (res)
256 dev_warn(dev, "failed to register restart handler\n");
257
258 pr_info("AT91 Watchdog Timer enabled (%d seconds%s)\n",
259 wdt_time, nowayout ? ", nowayout" : "");
260 return 0;
261}
262
263static int at91wdt_remove(struct platform_device *pdev)
264{
265 struct device *dev = &pdev->dev;
266 int res;
267
268 res = unregister_restart_handler(&at91rm9200_restart_nb);
269 if (res)
270 dev_warn(dev, "failed to unregister restart handler\n");
271
272 misc_deregister(&at91wdt_miscdev);
273 at91wdt_miscdev.parent = NULL;
274
275 return res;
276}
277
278static void at91wdt_shutdown(struct platform_device *pdev)
279{
280 at91_wdt_stop();
281}
282
283#ifdef CONFIG_PM
284
285static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message)
286{
287 at91_wdt_stop();
288 return 0;
289}
290
291static int at91wdt_resume(struct platform_device *pdev)
292{
293 if (at91wdt_busy)
294 at91_wdt_start();
295 return 0;
296}
297
298#else
299#define at91wdt_suspend NULL
300#define at91wdt_resume NULL
301#endif
302
303static const struct of_device_id at91_wdt_dt_ids[] = {
304 { .compatible = "atmel,at91rm9200-wdt" },
305 { /* sentinel */ }
306};
307MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);
308
309static struct platform_driver at91wdt_driver = {
310 .probe = at91wdt_probe,
311 .remove = at91wdt_remove,
312 .shutdown = at91wdt_shutdown,
313 .suspend = at91wdt_suspend,
314 .resume = at91wdt_resume,
315 .driver = {
316 .name = "atmel_st_watchdog",
317 .of_match_table = at91_wdt_dt_ids,
318 },
319};
320
321static int __init at91_wdt_init(void)
322{
323 /* Check that the heartbeat value is within range;
324 if not reset to the default */
325 if (at91_wdt_settimeout(wdt_time)) {
326 at91_wdt_settimeout(WDT_DEFAULT_TIME);
327 pr_info("wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
328 wdt_time);
329 }
330
331 return platform_driver_register(&at91wdt_driver);
332}
333
334static void __exit at91_wdt_exit(void)
335{
336 platform_driver_unregister(&at91wdt_driver);
337}
338
339module_init(at91_wdt_init);
340module_exit(at91_wdt_exit);
341
342MODULE_AUTHOR("Andrew Victor");
343MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
344MODULE_LICENSE("GPL");
345MODULE_ALIAS("platform:atmel_st_watchdog");