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Andrew Victor853807f2006-03-14 11:11:04 +02001/*
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
Joe Perches27c766a2012-02-15 15:06:19 -080012#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
Jiri Slaby1977f032007-10-18 23:40:25 -070014#include <linux/bitops.h>
Andrew Victor853807f2006-03-14 11:11:04 +020015#include <linux/errno.h>
16#include <linux/fs.h>
17#include <linux/init.h>
Jean-Christop PLAGNIOL-VILLARD02e07462009-01-23 10:06:07 +010018#include <linux/io.h>
Andrew Victor853807f2006-03-14 11:11:04 +020019#include <linux/kernel.h>
20#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>
Andrew Victor853807f2006-03-14 11:11:04 +020024#include <linux/types.h>
25#include <linux/watchdog.h>
Alan Cox27606002008-05-19 14:05:19 +010026#include <linux/uaccess.h>
Joachim Eastwooda6a1bcd2013-02-14 23:02:29 +010027#include <linux/of.h>
28#include <linux/of_device.h>
Russell Kinga09e64f2008-08-05 16:14:15 +010029#include <mach/at91_st.h>
Andrew Victor853807f2006-03-14 11:11:04 +020030
Andrew Victordfc7bd92006-05-21 15:32:59 +020031#define WDT_DEFAULT_TIME 5 /* seconds */
32#define WDT_MAX_TIME 256 /* seconds */
Andrew Victor853807f2006-03-14 11:11:04 +020033
34static int wdt_time = WDT_DEFAULT_TIME;
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010035static bool nowayout = WATCHDOG_NOWAYOUT;
Andrew Victor853807f2006-03-14 11:11:04 +020036
37module_param(wdt_time, int, 0);
Alan Cox27606002008-05-19 14:05:19 +010038MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
39 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
Andrew Victor853807f2006-03-14 11:11:04 +020040
Andrew Victordfc7bd92006-05-21 15:32:59 +020041#ifdef CONFIG_WATCHDOG_NOWAYOUT
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010042module_param(nowayout, bool, 0);
Alan Cox27606002008-05-19 14:05:19 +010043MODULE_PARM_DESC(nowayout,
44 "Watchdog cannot be stopped once started (default="
45 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Andrew Victordfc7bd92006-05-21 15:32:59 +020046#endif
Andrew Victor853807f2006-03-14 11:11:04 +020047
48
49static unsigned long at91wdt_busy;
50
51/* ......................................................................... */
52
53/*
54 * Disable the watchdog.
55 */
Alan Cox27606002008-05-19 14:05:19 +010056static inline void at91_wdt_stop(void)
Andrew Victor853807f2006-03-14 11:11:04 +020057{
Jean-Christophe PLAGNIOL-VILLARD5e9cf5e2012-02-20 11:07:39 +010058 at91_st_write(AT91_ST_WDMR, AT91_ST_EXTEN);
Andrew Victor853807f2006-03-14 11:11:04 +020059}
60
61/*
62 * Enable and reset the watchdog.
63 */
Alan Cox27606002008-05-19 14:05:19 +010064static inline void at91_wdt_start(void)
Andrew Victor853807f2006-03-14 11:11:04 +020065{
Jean-Christophe PLAGNIOL-VILLARD5e9cf5e2012-02-20 11:07:39 +010066 at91_st_write(AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN |
Alan Cox27606002008-05-19 14:05:19 +010067 (((65536 * wdt_time) >> 8) & AT91_ST_WDV));
Jean-Christophe PLAGNIOL-VILLARD5e9cf5e2012-02-20 11:07:39 +010068 at91_st_write(AT91_ST_CR, AT91_ST_WDRST);
Andrew Victor853807f2006-03-14 11:11:04 +020069}
70
71/*
72 * Reload the watchdog timer. (ie, pat the watchdog)
73 */
Alan Cox27606002008-05-19 14:05:19 +010074static inline void at91_wdt_reload(void)
Andrew Victor853807f2006-03-14 11:11:04 +020075{
Jean-Christophe PLAGNIOL-VILLARD5e9cf5e2012-02-20 11:07:39 +010076 at91_st_write(AT91_ST_CR, AT91_ST_WDRST);
Andrew Victor853807f2006-03-14 11:11:04 +020077}
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{
Alan Cox27606002008-05-19 14:05:19 +0100100 /* Disable the watchdog when file is closed */
Andrew Victor853807f2006-03-14 11:11:04 +0200101 if (!nowayout)
Alan Cox27606002008-05-19 14:05:19 +0100102 at91_wdt_stop();
Andrew Victor853807f2006-03-14 11:11:04 +0200103
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 /*
Andrew Victor2af29b72009-02-11 21:23:10 +0100114 * All counting occurs at SLOW_CLOCK / 128 = 256 Hz
Andrew Victor853807f2006-03-14 11:11:04 +0200115 *
116 * Since WDV is a 16-bit counter, the maximum period is
Andrew Victor2af29b72009-02-11 21:23:10 +0100117 * 65536 / 256 = 256 seconds.
Andrew Victor853807f2006-03-14 11:11:04 +0200118 */
119 if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
120 return -EINVAL;
121
Alan Cox27606002008-05-19 14:05:19 +0100122 /* Set new watchdog time. It will be used when
123 at91_wdt_start() is called. */
Andrew Victor853807f2006-03-14 11:11:04 +0200124 wdt_time = new_time;
125 return 0;
126}
127
Wim Van Sebroeck42747d72009-12-26 18:55:22 +0000128static const struct watchdog_info at91_wdt_info = {
Andrew Victor853807f2006-03-14 11:11:04 +0200129 .identity = "at91 watchdog",
130 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
131};
132
133/*
134 * Handle commands from user-space.
135 */
Adrian Bunk3c4fafd2008-08-08 18:57:45 +0300136static long at91_wdt_ioctl(struct file *file,
Alan Cox27606002008-05-19 14:05:19 +0100137 unsigned int cmd, unsigned long arg)
Andrew Victor853807f2006-03-14 11:11:04 +0200138{
139 void __user *argp = (void __user *)arg;
140 int __user *p = argp;
141 int new_value;
142
Alan Cox27606002008-05-19 14:05:19 +0100143 switch (cmd) {
Alan Cox27606002008-05-19 14:05:19 +0100144 case WDIOC_GETSUPPORT:
145 return copy_to_user(argp, &at91_wdt_info,
146 sizeof(at91_wdt_info)) ? -EFAULT : 0;
Alan Cox27606002008-05-19 14:05:19 +0100147 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)
Andrew Victor853807f2006-03-14 11:11:04 +0200156 at91_wdt_start();
Alan Cox27606002008-05-19 14:05:19 +0100157 return 0;
Wim Van Sebroeck0c060902008-07-18 11:41:17 +0000158 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);
Alan Cox27606002008-05-19 14:05:19 +0100172 default:
173 return -ENOTTY;
Andrew Victor853807f2006-03-14 11:11:04 +0200174 }
175}
176
177/*
178 * Pat the watchdog whenever device is written to.
179 */
Alan Cox27606002008-05-19 14:05:19 +0100180static ssize_t at91_wdt_write(struct file *file, const char *data,
181 size_t len, loff_t *ppos)
Andrew Victor853807f2006-03-14 11:11:04 +0200182{
183 at91_wdt_reload(); /* pat the watchdog */
184 return len;
185}
186
187/* ......................................................................... */
188
Arjan van de Ven62322d22006-07-03 00:24:21 -0700189static const struct file_operations at91wdt_fops = {
Andrew Victor853807f2006-03-14 11:11:04 +0200190 .owner = THIS_MODULE,
191 .llseek = no_llseek,
Alan Cox27606002008-05-19 14:05:19 +0100192 .unlocked_ioctl = at91_wdt_ioctl,
Andrew Victor853807f2006-03-14 11:11:04 +0200193 .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
Bill Pemberton2d991a12012-11-19 13:21:41 -0500204static int at91wdt_probe(struct platform_device *pdev)
Andrew Victor853807f2006-03-14 11:11:04 +0200205{
206 int res;
207
Andrew Victore0b79e02006-12-04 15:56:18 +0200208 if (at91wdt_miscdev.parent)
Andrew Victordfc7bd92006-05-21 15:32:59 +0200209 return -EBUSY;
Andrew Victore0b79e02006-12-04 15:56:18 +0200210 at91wdt_miscdev.parent = &pdev->dev;
Andrew Victor853807f2006-03-14 11:11:04 +0200211
212 res = misc_register(&at91wdt_miscdev);
213 if (res)
214 return res;
215
Joe Perches27c766a2012-02-15 15:06:19 -0800216 pr_info("AT91 Watchdog Timer enabled (%d seconds%s)\n",
217 wdt_time, nowayout ? ", nowayout" : "");
Andrew Victor853807f2006-03-14 11:11:04 +0200218 return 0;
219}
220
Bill Pemberton4b12b892012-11-19 13:26:24 -0500221static int at91wdt_remove(struct platform_device *pdev)
Andrew Victordfc7bd92006-05-21 15:32:59 +0200222{
223 int res;
224
225 res = misc_deregister(&at91wdt_miscdev);
226 if (!res)
Andrew Victore0b79e02006-12-04 15:56:18 +0200227 at91wdt_miscdev.parent = NULL;
Andrew Victordfc7bd92006-05-21 15:32:59 +0200228
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();
Ilpo Jarvinen95f62bd2008-08-19 09:01:14 +0300249 return 0;
Andrew Victordfc7bd92006-05-21 15:32:59 +0200250}
251
252#else
253#define at91wdt_suspend NULL
254#define at91wdt_resume NULL
255#endif
256
Joachim Eastwooda6a1bcd2013-02-14 23:02:29 +0100257static 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
Andrew Victordfc7bd92006-05-21 15:32:59 +0200263static struct platform_driver at91wdt_driver = {
264 .probe = at91wdt_probe,
Bill Pemberton82268712012-11-19 13:21:12 -0500265 .remove = at91wdt_remove,
Andrew Victordfc7bd92006-05-21 15:32:59 +0200266 .shutdown = at91wdt_shutdown,
267 .suspend = at91wdt_suspend,
268 .resume = at91wdt_resume,
269 .driver = {
270 .name = "at91_wdt",
Sachin Kamat85eee812013-09-30 10:12:51 +0530271 .of_match_table = at91_wdt_dt_ids,
Andrew Victordfc7bd92006-05-21 15:32:59 +0200272 },
273};
274
275static int __init at91_wdt_init(void)
276{
Alan Cox27606002008-05-19 14:05:19 +0100277 /* Check that the heartbeat value is within range;
278 if not reset to the default */
Andrew Victordfc7bd92006-05-21 15:32:59 +0200279 if (at91_wdt_settimeout(wdt_time)) {
280 at91_wdt_settimeout(WDT_DEFAULT_TIME);
Joe Perches27c766a2012-02-15 15:06:19 -0800281 pr_info("wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
282 wdt_time);
Andrew Victordfc7bd92006-05-21 15:32:59 +0200283 }
284
285 return platform_driver_register(&at91wdt_driver);
286}
287
Andrew Victor853807f2006-03-14 11:11:04 +0200288static void __exit at91_wdt_exit(void)
289{
Andrew Victordfc7bd92006-05-21 15:32:59 +0200290 platform_driver_unregister(&at91wdt_driver);
Andrew Victor853807f2006-03-14 11:11:04 +0200291}
292
293module_init(at91_wdt_init);
294module_exit(at91_wdt_exit);
295
296MODULE_AUTHOR("Andrew Victor");
297MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
298MODULE_LICENSE("GPL");
Kay Sieversf37d1932008-04-10 21:29:23 -0700299MODULE_ALIAS("platform:at91_wdt");