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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 .unlocked_ioctl = at91_wdt_ioctl,
214 .compat_ioctl = compat_ptr_ioctl,
215 .open = at91_wdt_open,
216 .release = at91_wdt_close,
217 .write = at91_wdt_write,
218};
219
220static struct miscdevice at91wdt_miscdev = {
221 .minor = WATCHDOG_MINOR,
222 .name = "watchdog",
223 .fops = &at91wdt_fops,
224};
225
226static int at91wdt_probe(struct platform_device *pdev)
227{
228 struct device *dev = &pdev->dev;
229 struct device *parent;
230 int res;
231
232 if (at91wdt_miscdev.parent)
233 return -EBUSY;
234 at91wdt_miscdev.parent = &pdev->dev;
235
236 parent = dev->parent;
237 if (!parent) {
238 dev_err(dev, "no parent\n");
239 return -ENODEV;
240 }
241
242 regmap_st = syscon_node_to_regmap(parent->of_node);
243 if (IS_ERR(regmap_st))
244 return -ENODEV;
245
246 res = misc_register(&at91wdt_miscdev);
247 if (res)
248 return res;
249
250 res = register_restart_handler(&at91rm9200_restart_nb);
251 if (res)
252 dev_warn(dev, "failed to register restart handler\n");
253
254 pr_info("AT91 Watchdog Timer enabled (%d seconds%s)\n",
255 wdt_time, nowayout ? ", nowayout" : "");
256 return 0;
257}
258
259static void at91wdt_remove(struct platform_device *pdev)
260{
261 struct device *dev = &pdev->dev;
262 int res;
263
264 res = unregister_restart_handler(&at91rm9200_restart_nb);
265 if (res)
266 dev_warn(dev, "failed to unregister restart handler\n");
267
268 misc_deregister(&at91wdt_miscdev);
269 at91wdt_miscdev.parent = NULL;
270}
271
272static void at91wdt_shutdown(struct platform_device *pdev)
273{
274 at91_wdt_stop();
275}
276
277static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message)
278{
279 at91_wdt_stop();
280 return 0;
281}
282
283static int at91wdt_resume(struct platform_device *pdev)
284{
285 if (at91wdt_busy)
286 at91_wdt_start();
287 return 0;
288}
289
290static const struct of_device_id at91_wdt_dt_ids[] = {
291 { .compatible = "atmel,at91rm9200-wdt" },
292 { /* sentinel */ }
293};
294MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);
295
296static struct platform_driver at91wdt_driver = {
297 .probe = at91wdt_probe,
298 .remove = at91wdt_remove,
299 .shutdown = at91wdt_shutdown,
300 .suspend = pm_ptr(at91wdt_suspend),
301 .resume = pm_ptr(at91wdt_resume),
302 .driver = {
303 .name = "atmel_st_watchdog",
304 .of_match_table = at91_wdt_dt_ids,
305 },
306};
307
308static int __init at91_wdt_init(void)
309{
310 /* Check that the heartbeat value is within range;
311 if not reset to the default */
312 if (at91_wdt_settimeout(wdt_time)) {
313 at91_wdt_settimeout(WDT_DEFAULT_TIME);
314 pr_info("wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
315 wdt_time);
316 }
317
318 return platform_driver_register(&at91wdt_driver);
319}
320
321static void __exit at91_wdt_exit(void)
322{
323 platform_driver_unregister(&at91wdt_driver);
324}
325
326module_init(at91_wdt_init);
327module_exit(at91_wdt_exit);
328
329MODULE_AUTHOR("Andrew Victor");
330MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
331MODULE_LICENSE("GPL");
332MODULE_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/errno.h>
16#include <linux/fs.h>
17#include <linux/init.h>
18#include <linux/io.h>
19#include <linux/kernel.h>
20#include <linux/miscdevice.h>
21#include <linux/module.h>
22#include <linux/moduleparam.h>
23#include <linux/platform_device.h>
24#include <linux/types.h>
25#include <linux/watchdog.h>
26#include <linux/uaccess.h>
27#include <linux/of.h>
28#include <linux/of_device.h>
29#include <mach/at91_st.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;
36
37module_param(wdt_time, int, 0);
38MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
39 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
40
41#ifdef CONFIG_WATCHDOG_NOWAYOUT
42module_param(nowayout, bool, 0);
43MODULE_PARM_DESC(nowayout,
44 "Watchdog cannot be stopped once started (default="
45 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
46#endif
47
48
49static unsigned long at91wdt_busy;
50
51/* ......................................................................... */
52
53/*
54 * Disable the watchdog.
55 */
56static inline void at91_wdt_stop(void)
57{
58 at91_st_write(AT91_ST_WDMR, AT91_ST_EXTEN);
59}
60
61/*
62 * Enable and reset the watchdog.
63 */
64static inline void at91_wdt_start(void)
65{
66 at91_st_write(AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN |
67 (((65536 * wdt_time) >> 8) & AT91_ST_WDV));
68 at91_st_write(AT91_ST_CR, AT91_ST_WDRST);
69}
70
71/*
72 * Reload the watchdog timer. (ie, pat the watchdog)
73 */
74static inline void at91_wdt_reload(void)
75{
76 at91_st_write(AT91_ST_CR, AT91_ST_WDRST);
77}
78
79/* ......................................................................... */
80
81/*
82 * Watchdog device is opened, and watchdog starts running.
83 */
84static int at91_wdt_open(struct inode *inode, struct file *file)
85{
86 if (test_and_set_bit(0, &at91wdt_busy))
87 return -EBUSY;
88
89 at91_wdt_start();
90 return nonseekable_open(inode, file);
91}
92
93/*
94 * Close the watchdog device.
95 * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
96 * disabled.
97 */
98static int at91_wdt_close(struct inode *inode, struct file *file)
99{
100 /* Disable the watchdog when file is closed */
101 if (!nowayout)
102 at91_wdt_stop();
103
104 clear_bit(0, &at91wdt_busy);
105 return 0;
106}
107
108/*
109 * Change the watchdog time interval.
110 */
111static int at91_wdt_settimeout(int new_time)
112{
113 /*
114 * All counting occurs at SLOW_CLOCK / 128 = 256 Hz
115 *
116 * Since WDV is a 16-bit counter, the maximum period is
117 * 65536 / 256 = 256 seconds.
118 */
119 if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
120 return -EINVAL;
121
122 /* Set new watchdog time. It will be used when
123 at91_wdt_start() is called. */
124 wdt_time = new_time;
125 return 0;
126}
127
128static const struct watchdog_info at91_wdt_info = {
129 .identity = "at91 watchdog",
130 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
131};
132
133/*
134 * Handle commands from user-space.
135 */
136static long at91_wdt_ioctl(struct file *file,
137 unsigned int cmd, unsigned long arg)
138{
139 void __user *argp = (void __user *)arg;
140 int __user *p = argp;
141 int new_value;
142
143 switch (cmd) {
144 case WDIOC_GETSUPPORT:
145 return copy_to_user(argp, &at91_wdt_info,
146 sizeof(at91_wdt_info)) ? -EFAULT : 0;
147 case WDIOC_GETSTATUS:
148 case WDIOC_GETBOOTSTATUS:
149 return put_user(0, p);
150 case WDIOC_SETOPTIONS:
151 if (get_user(new_value, p))
152 return -EFAULT;
153 if (new_value & WDIOS_DISABLECARD)
154 at91_wdt_stop();
155 if (new_value & WDIOS_ENABLECARD)
156 at91_wdt_start();
157 return 0;
158 case WDIOC_KEEPALIVE:
159 at91_wdt_reload(); /* pat the watchdog */
160 return 0;
161 case WDIOC_SETTIMEOUT:
162 if (get_user(new_value, p))
163 return -EFAULT;
164 if (at91_wdt_settimeout(new_value))
165 return -EINVAL;
166 /* Enable new time value */
167 at91_wdt_start();
168 /* Return current value */
169 return put_user(wdt_time, p);
170 case WDIOC_GETTIMEOUT:
171 return put_user(wdt_time, p);
172 default:
173 return -ENOTTY;
174 }
175}
176
177/*
178 * Pat the watchdog whenever device is written to.
179 */
180static ssize_t at91_wdt_write(struct file *file, const char *data,
181 size_t len, loff_t *ppos)
182{
183 at91_wdt_reload(); /* pat the watchdog */
184 return len;
185}
186
187/* ......................................................................... */
188
189static const struct file_operations at91wdt_fops = {
190 .owner = THIS_MODULE,
191 .llseek = no_llseek,
192 .unlocked_ioctl = at91_wdt_ioctl,
193 .open = at91_wdt_open,
194 .release = at91_wdt_close,
195 .write = at91_wdt_write,
196};
197
198static struct miscdevice at91wdt_miscdev = {
199 .minor = WATCHDOG_MINOR,
200 .name = "watchdog",
201 .fops = &at91wdt_fops,
202};
203
204static int at91wdt_probe(struct platform_device *pdev)
205{
206 int res;
207
208 if (at91wdt_miscdev.parent)
209 return -EBUSY;
210 at91wdt_miscdev.parent = &pdev->dev;
211
212 res = misc_register(&at91wdt_miscdev);
213 if (res)
214 return res;
215
216 pr_info("AT91 Watchdog Timer enabled (%d seconds%s)\n",
217 wdt_time, nowayout ? ", nowayout" : "");
218 return 0;
219}
220
221static int at91wdt_remove(struct platform_device *pdev)
222{
223 int res;
224
225 res = misc_deregister(&at91wdt_miscdev);
226 if (!res)
227 at91wdt_miscdev.parent = NULL;
228
229 return res;
230}
231
232static void at91wdt_shutdown(struct platform_device *pdev)
233{
234 at91_wdt_stop();
235}
236
237#ifdef CONFIG_PM
238
239static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message)
240{
241 at91_wdt_stop();
242 return 0;
243}
244
245static int at91wdt_resume(struct platform_device *pdev)
246{
247 if (at91wdt_busy)
248 at91_wdt_start();
249 return 0;
250}
251
252#else
253#define at91wdt_suspend NULL
254#define at91wdt_resume NULL
255#endif
256
257static const struct of_device_id at91_wdt_dt_ids[] = {
258 { .compatible = "atmel,at91rm9200-wdt" },
259 { /* sentinel */ }
260};
261MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);
262
263static struct platform_driver at91wdt_driver = {
264 .probe = at91wdt_probe,
265 .remove = at91wdt_remove,
266 .shutdown = at91wdt_shutdown,
267 .suspend = at91wdt_suspend,
268 .resume = at91wdt_resume,
269 .driver = {
270 .name = "at91_wdt",
271 .owner = THIS_MODULE,
272 .of_match_table = at91_wdt_dt_ids,
273 },
274};
275
276static int __init at91_wdt_init(void)
277{
278 /* Check that the heartbeat value is within range;
279 if not reset to the default */
280 if (at91_wdt_settimeout(wdt_time)) {
281 at91_wdt_settimeout(WDT_DEFAULT_TIME);
282 pr_info("wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
283 wdt_time);
284 }
285
286 return platform_driver_register(&at91wdt_driver);
287}
288
289static void __exit at91_wdt_exit(void)
290{
291 platform_driver_unregister(&at91wdt_driver);
292}
293
294module_init(at91_wdt_init);
295module_exit(at91_wdt_exit);
296
297MODULE_AUTHOR("Andrew Victor");
298MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
299MODULE_LICENSE("GPL");
300MODULE_ALIAS("platform:at91_wdt");