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Marcus Folkesson2e62c492018-03-16 16:14:11 +01001// SPDX-License-Identifier: GPL-2.0+
Andrew Victor853807f2006-03-14 11:11:04 +02002/*
3 * Watchdog driver for Atmel AT91RM9200 (Thunder)
4 *
5 * Copyright (C) 2003 SAN People (Pty) Ltd
6 *
Andrew Victor853807f2006-03-14 11:11:04 +02007 */
8
Joe Perches27c766a2012-02-15 15:06:19 -08009#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
Jiri Slaby1977f032007-10-18 23:40:25 -070011#include <linux/bitops.h>
Alexandre Belloni9ab45f32015-03-12 13:07:28 +010012#include <linux/delay.h>
Andrew Victor853807f2006-03-14 11:11:04 +020013#include <linux/errno.h>
14#include <linux/fs.h>
15#include <linux/init.h>
Jean-Christop PLAGNIOL-VILLARD02e07462009-01-23 10:06:07 +010016#include <linux/io.h>
Andrew Victor853807f2006-03-14 11:11:04 +020017#include <linux/kernel.h>
Alexandre Belloni8432f9e2015-03-12 13:07:27 +010018#include <linux/mfd/syscon.h>
19#include <linux/mfd/syscon/atmel-st.h>
Andrew Victor853807f2006-03-14 11:11:04 +020020#include <linux/miscdevice.h>
21#include <linux/module.h>
22#include <linux/moduleparam.h>
Andrew Victordfc7bd92006-05-21 15:32:59 +020023#include <linux/platform_device.h>
Alexandre Belloni9ab45f32015-03-12 13:07:28 +010024#include <linux/reboot.h>
Alexandre Belloni8432f9e2015-03-12 13:07:27 +010025#include <linux/regmap.h>
Andrew Victor853807f2006-03-14 11:11:04 +020026#include <linux/types.h>
27#include <linux/watchdog.h>
Alan Cox27606002008-05-19 14:05:19 +010028#include <linux/uaccess.h>
Joachim Eastwooda6a1bcd2013-02-14 23:02:29 +010029#include <linux/of.h>
30#include <linux/of_device.h>
Andrew Victor853807f2006-03-14 11:11:04 +020031
Andrew Victordfc7bd92006-05-21 15:32:59 +020032#define WDT_DEFAULT_TIME 5 /* seconds */
33#define WDT_MAX_TIME 256 /* seconds */
Andrew Victor853807f2006-03-14 11:11:04 +020034
35static int wdt_time = WDT_DEFAULT_TIME;
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010036static bool nowayout = WATCHDOG_NOWAYOUT;
Alexandre Belloni8432f9e2015-03-12 13:07:27 +010037static struct regmap *regmap_st;
Andrew Victor853807f2006-03-14 11:11:04 +020038
39module_param(wdt_time, int, 0);
Alan Cox27606002008-05-19 14:05:19 +010040MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
41 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
Andrew Victor853807f2006-03-14 11:11:04 +020042
Andrew Victordfc7bd92006-05-21 15:32:59 +020043#ifdef CONFIG_WATCHDOG_NOWAYOUT
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010044module_param(nowayout, bool, 0);
Alan Cox27606002008-05-19 14:05:19 +010045MODULE_PARM_DESC(nowayout,
46 "Watchdog cannot be stopped once started (default="
47 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Andrew Victordfc7bd92006-05-21 15:32:59 +020048#endif
Andrew Victor853807f2006-03-14 11:11:04 +020049
50
51static unsigned long at91wdt_busy;
52
53/* ......................................................................... */
54
Alexandre Belloni9ab45f32015-03-12 13:07:28 +010055static int at91rm9200_restart(struct notifier_block *this,
56 unsigned long mode, void *cmd)
57{
58 /*
59 * Perform a hardware reset with the use of the Watchdog timer.
60 */
61 regmap_write(regmap_st, AT91_ST_WDMR,
62 AT91_ST_RSTEN | AT91_ST_EXTEN | 1);
63 regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
64
65 mdelay(2000);
66
67 pr_emerg("Unable to restart system\n");
68 return NOTIFY_DONE;
69}
70
71static struct notifier_block at91rm9200_restart_nb = {
72 .notifier_call = at91rm9200_restart,
73 .priority = 192,
74};
75
Andrew Victor853807f2006-03-14 11:11:04 +020076/*
77 * Disable the watchdog.
78 */
Alan Cox27606002008-05-19 14:05:19 +010079static inline void at91_wdt_stop(void)
Andrew Victor853807f2006-03-14 11:11:04 +020080{
Alexandre Belloni8432f9e2015-03-12 13:07:27 +010081 regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN);
Andrew Victor853807f2006-03-14 11:11:04 +020082}
83
84/*
85 * Enable and reset the watchdog.
86 */
Alan Cox27606002008-05-19 14:05:19 +010087static inline void at91_wdt_start(void)
Andrew Victor853807f2006-03-14 11:11:04 +020088{
Alexandre Belloni8432f9e2015-03-12 13:07:27 +010089 regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN |
Alan Cox27606002008-05-19 14:05:19 +010090 (((65536 * wdt_time) >> 8) & AT91_ST_WDV));
Alexandre Belloni8432f9e2015-03-12 13:07:27 +010091 regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
Andrew Victor853807f2006-03-14 11:11:04 +020092}
93
94/*
95 * Reload the watchdog timer. (ie, pat the watchdog)
96 */
Alan Cox27606002008-05-19 14:05:19 +010097static inline void at91_wdt_reload(void)
Andrew Victor853807f2006-03-14 11:11:04 +020098{
Alexandre Belloni8432f9e2015-03-12 13:07:27 +010099 regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
Andrew Victor853807f2006-03-14 11:11:04 +0200100}
101
102/* ......................................................................... */
103
104/*
105 * Watchdog device is opened, and watchdog starts running.
106 */
107static int at91_wdt_open(struct inode *inode, struct file *file)
108{
109 if (test_and_set_bit(0, &at91wdt_busy))
110 return -EBUSY;
111
112 at91_wdt_start();
Kirill Smelkovc5bf68f2019-03-26 23:51:19 +0300113 return stream_open(inode, file);
Andrew Victor853807f2006-03-14 11:11:04 +0200114}
115
116/*
117 * Close the watchdog device.
118 * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
119 * disabled.
120 */
121static int at91_wdt_close(struct inode *inode, struct file *file)
122{
Alan Cox27606002008-05-19 14:05:19 +0100123 /* Disable the watchdog when file is closed */
Andrew Victor853807f2006-03-14 11:11:04 +0200124 if (!nowayout)
Alan Cox27606002008-05-19 14:05:19 +0100125 at91_wdt_stop();
Andrew Victor853807f2006-03-14 11:11:04 +0200126
127 clear_bit(0, &at91wdt_busy);
128 return 0;
129}
130
131/*
132 * Change the watchdog time interval.
133 */
134static int at91_wdt_settimeout(int new_time)
135{
136 /*
Andrew Victor2af29b72009-02-11 21:23:10 +0100137 * All counting occurs at SLOW_CLOCK / 128 = 256 Hz
Andrew Victor853807f2006-03-14 11:11:04 +0200138 *
139 * Since WDV is a 16-bit counter, the maximum period is
Andrew Victor2af29b72009-02-11 21:23:10 +0100140 * 65536 / 256 = 256 seconds.
Andrew Victor853807f2006-03-14 11:11:04 +0200141 */
142 if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
143 return -EINVAL;
144
Alan Cox27606002008-05-19 14:05:19 +0100145 /* Set new watchdog time. It will be used when
146 at91_wdt_start() is called. */
Andrew Victor853807f2006-03-14 11:11:04 +0200147 wdt_time = new_time;
148 return 0;
149}
150
Wim Van Sebroeck42747d72009-12-26 18:55:22 +0000151static const struct watchdog_info at91_wdt_info = {
Andrew Victor853807f2006-03-14 11:11:04 +0200152 .identity = "at91 watchdog",
153 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
154};
155
156/*
157 * Handle commands from user-space.
158 */
Adrian Bunk3c4fafd2008-08-08 18:57:45 +0300159static long at91_wdt_ioctl(struct file *file,
Alan Cox27606002008-05-19 14:05:19 +0100160 unsigned int cmd, unsigned long arg)
Andrew Victor853807f2006-03-14 11:11:04 +0200161{
162 void __user *argp = (void __user *)arg;
163 int __user *p = argp;
164 int new_value;
165
Alan Cox27606002008-05-19 14:05:19 +0100166 switch (cmd) {
Alan Cox27606002008-05-19 14:05:19 +0100167 case WDIOC_GETSUPPORT:
168 return copy_to_user(argp, &at91_wdt_info,
169 sizeof(at91_wdt_info)) ? -EFAULT : 0;
Alan Cox27606002008-05-19 14:05:19 +0100170 case WDIOC_GETSTATUS:
171 case WDIOC_GETBOOTSTATUS:
172 return put_user(0, p);
173 case WDIOC_SETOPTIONS:
174 if (get_user(new_value, p))
175 return -EFAULT;
176 if (new_value & WDIOS_DISABLECARD)
177 at91_wdt_stop();
178 if (new_value & WDIOS_ENABLECARD)
Andrew Victor853807f2006-03-14 11:11:04 +0200179 at91_wdt_start();
Alan Cox27606002008-05-19 14:05:19 +0100180 return 0;
Wim Van Sebroeck0c060902008-07-18 11:41:17 +0000181 case WDIOC_KEEPALIVE:
182 at91_wdt_reload(); /* pat the watchdog */
183 return 0;
184 case WDIOC_SETTIMEOUT:
185 if (get_user(new_value, p))
186 return -EFAULT;
187 if (at91_wdt_settimeout(new_value))
188 return -EINVAL;
189 /* Enable new time value */
190 at91_wdt_start();
191 /* Return current value */
192 return put_user(wdt_time, p);
193 case WDIOC_GETTIMEOUT:
194 return put_user(wdt_time, p);
Alan Cox27606002008-05-19 14:05:19 +0100195 default:
196 return -ENOTTY;
Andrew Victor853807f2006-03-14 11:11:04 +0200197 }
198}
199
200/*
201 * Pat the watchdog whenever device is written to.
202 */
Alan Cox27606002008-05-19 14:05:19 +0100203static ssize_t at91_wdt_write(struct file *file, const char *data,
204 size_t len, loff_t *ppos)
Andrew Victor853807f2006-03-14 11:11:04 +0200205{
206 at91_wdt_reload(); /* pat the watchdog */
207 return len;
208}
209
210/* ......................................................................... */
211
Arjan van de Ven62322d22006-07-03 00:24:21 -0700212static const struct file_operations at91wdt_fops = {
Andrew Victor853807f2006-03-14 11:11:04 +0200213 .owner = THIS_MODULE,
214 .llseek = no_llseek,
Alan Cox27606002008-05-19 14:05:19 +0100215 .unlocked_ioctl = at91_wdt_ioctl,
Andrew Victor853807f2006-03-14 11:11:04 +0200216 .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
Bill Pemberton2d991a12012-11-19 13:21:41 -0500227static int at91wdt_probe(struct platform_device *pdev)
Andrew Victor853807f2006-03-14 11:11:04 +0200228{
Alexandre Belloni8432f9e2015-03-12 13:07:27 +0100229 struct device *dev = &pdev->dev;
230 struct device *parent;
Andrew Victor853807f2006-03-14 11:11:04 +0200231 int res;
232
Andrew Victore0b79e02006-12-04 15:56:18 +0200233 if (at91wdt_miscdev.parent)
Andrew Victordfc7bd92006-05-21 15:32:59 +0200234 return -EBUSY;
Andrew Victore0b79e02006-12-04 15:56:18 +0200235 at91wdt_miscdev.parent = &pdev->dev;
Andrew Victor853807f2006-03-14 11:11:04 +0200236
Alexandre Belloni8432f9e2015-03-12 13:07:27 +0100237 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);
Bjorn Anderssonbf5125d2015-08-17 09:19:03 -0700244 if (IS_ERR(regmap_st))
Alexandre Belloni8432f9e2015-03-12 13:07:27 +0100245 return -ENODEV;
246
Andrew Victor853807f2006-03-14 11:11:04 +0200247 res = misc_register(&at91wdt_miscdev);
248 if (res)
249 return res;
250
Alexandre Belloni9ab45f32015-03-12 13:07:28 +0100251 res = register_restart_handler(&at91rm9200_restart_nb);
252 if (res)
253 dev_warn(dev, "failed to register restart handler\n");
254
Joe Perches27c766a2012-02-15 15:06:19 -0800255 pr_info("AT91 Watchdog Timer enabled (%d seconds%s)\n",
256 wdt_time, nowayout ? ", nowayout" : "");
Andrew Victor853807f2006-03-14 11:11:04 +0200257 return 0;
258}
259
Bill Pemberton4b12b892012-11-19 13:26:24 -0500260static int at91wdt_remove(struct platform_device *pdev)
Andrew Victordfc7bd92006-05-21 15:32:59 +0200261{
Alexandre Belloni9ab45f32015-03-12 13:07:28 +0100262 struct device *dev = &pdev->dev;
Andrew Victordfc7bd92006-05-21 15:32:59 +0200263 int res;
264
Alexandre Belloni9ab45f32015-03-12 13:07:28 +0100265 res = unregister_restart_handler(&at91rm9200_restart_nb);
266 if (res)
267 dev_warn(dev, "failed to unregister restart handler\n");
268
Greg Kroah-Hartmanf368ed62015-07-30 15:59:57 -0700269 misc_deregister(&at91wdt_miscdev);
270 at91wdt_miscdev.parent = NULL;
Andrew Victordfc7bd92006-05-21 15:32:59 +0200271
272 return res;
273}
274
275static void at91wdt_shutdown(struct platform_device *pdev)
276{
277 at91_wdt_stop();
278}
279
280#ifdef CONFIG_PM
281
282static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message)
283{
284 at91_wdt_stop();
285 return 0;
286}
287
288static int at91wdt_resume(struct platform_device *pdev)
289{
290 if (at91wdt_busy)
291 at91_wdt_start();
Ilpo Jarvinen95f62bd2008-08-19 09:01:14 +0300292 return 0;
Andrew Victordfc7bd92006-05-21 15:32:59 +0200293}
294
295#else
296#define at91wdt_suspend NULL
297#define at91wdt_resume NULL
298#endif
299
Joachim Eastwooda6a1bcd2013-02-14 23:02:29 +0100300static const struct of_device_id at91_wdt_dt_ids[] = {
301 { .compatible = "atmel,at91rm9200-wdt" },
302 { /* sentinel */ }
303};
304MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);
305
Andrew Victordfc7bd92006-05-21 15:32:59 +0200306static struct platform_driver at91wdt_driver = {
307 .probe = at91wdt_probe,
Bill Pemberton82268712012-11-19 13:21:12 -0500308 .remove = at91wdt_remove,
Andrew Victordfc7bd92006-05-21 15:32:59 +0200309 .shutdown = at91wdt_shutdown,
310 .suspend = at91wdt_suspend,
311 .resume = at91wdt_resume,
312 .driver = {
Alexandre Belloni8432f9e2015-03-12 13:07:27 +0100313 .name = "atmel_st_watchdog",
Sachin Kamat85eee812013-09-30 10:12:51 +0530314 .of_match_table = at91_wdt_dt_ids,
Andrew Victordfc7bd92006-05-21 15:32:59 +0200315 },
316};
317
318static int __init at91_wdt_init(void)
319{
Alan Cox27606002008-05-19 14:05:19 +0100320 /* Check that the heartbeat value is within range;
321 if not reset to the default */
Andrew Victordfc7bd92006-05-21 15:32:59 +0200322 if (at91_wdt_settimeout(wdt_time)) {
323 at91_wdt_settimeout(WDT_DEFAULT_TIME);
Joe Perches27c766a2012-02-15 15:06:19 -0800324 pr_info("wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
325 wdt_time);
Andrew Victordfc7bd92006-05-21 15:32:59 +0200326 }
327
328 return platform_driver_register(&at91wdt_driver);
329}
330
Andrew Victor853807f2006-03-14 11:11:04 +0200331static void __exit at91_wdt_exit(void)
332{
Andrew Victordfc7bd92006-05-21 15:32:59 +0200333 platform_driver_unregister(&at91wdt_driver);
Andrew Victor853807f2006-03-14 11:11:04 +0200334}
335
336module_init(at91_wdt_init);
337module_exit(at91_wdt_exit);
338
339MODULE_AUTHOR("Andrew Victor");
340MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
341MODULE_LICENSE("GPL");
Alexandre Belloni8432f9e2015-03-12 13:07:27 +0100342MODULE_ALIAS("platform:atmel_st_watchdog");