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Andrew Victorccb8f432007-05-14 14:45:25 +02001/*
2 * Watchdog driver for Kendin/Micrel KS8695.
3 *
4 * (C) 2007 Andrew Victor
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
Joe Perches27c766a2012-02-15 15:06:19 -080011#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
Jiri Slaby1977f032007-10-18 23:40:25 -070013#include <linux/bitops.h>
Andrew Victorccb8f432007-05-14 14:45:25 +020014#include <linux/errno.h>
15#include <linux/fs.h>
16#include <linux/init.h>
17#include <linux/kernel.h>
18#include <linux/miscdevice.h>
19#include <linux/module.h>
20#include <linux/moduleparam.h>
21#include <linux/platform_device.h>
22#include <linux/types.h>
23#include <linux/watchdog.h>
Alan Coxf4fabce2008-05-19 14:06:53 +010024#include <linux/io.h>
25#include <linux/uaccess.h>
Yegor Yefremov568dba62010-12-14 16:29:31 +010026#include <mach/hardware.h>
Linus Walleijcab463a2012-09-11 07:48:15 +020027
28#define KS8695_TMR_OFFSET (0xF0000 + 0xE400)
29#define KS8695_TMR_VA (KS8695_IO_VA + KS8695_TMR_OFFSET)
30
31/*
32 * Timer registers
33 */
34#define KS8695_TMCON (0x00) /* Timer Control Register */
35#define KS8695_T0TC (0x08) /* Timer 0 Timeout Count Register */
36#define TMCON_T0EN (1 << 0) /* Timer 0 Enable */
37
38/* Timer0 Timeout Counter Register */
39#define T0TC_WATCHDOG (0xff) /* Enable watchdog mode */
Andrew Victorccb8f432007-05-14 14:45:25 +020040
Andrew Victorccb8f432007-05-14 14:45:25 +020041#define WDT_DEFAULT_TIME 5 /* seconds */
42#define WDT_MAX_TIME 171 /* seconds */
43
44static int wdt_time = WDT_DEFAULT_TIME;
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010045static bool nowayout = WATCHDOG_NOWAYOUT;
Andrew Victorccb8f432007-05-14 14:45:25 +020046
47module_param(wdt_time, int, 0);
Alan Coxf4fabce2008-05-19 14:06:53 +010048MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
49 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
Andrew Victorccb8f432007-05-14 14:45:25 +020050
51#ifdef CONFIG_WATCHDOG_NOWAYOUT
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010052module_param(nowayout, bool, 0);
Alan Coxf4fabce2008-05-19 14:06:53 +010053MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
54 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Andrew Victorccb8f432007-05-14 14:45:25 +020055#endif
56
57
58static unsigned long ks8695wdt_busy;
Axel Lin1334f322011-11-29 13:54:01 +080059static DEFINE_SPINLOCK(ks8695_lock);
Andrew Victorccb8f432007-05-14 14:45:25 +020060
61/* ......................................................................... */
62
63/*
64 * Disable the watchdog.
65 */
Alan Coxf4fabce2008-05-19 14:06:53 +010066static inline void ks8695_wdt_stop(void)
Andrew Victorccb8f432007-05-14 14:45:25 +020067{
68 unsigned long tmcon;
69
Alan Coxf4fabce2008-05-19 14:06:53 +010070 spin_lock(&ks8695_lock);
Andrew Victorccb8f432007-05-14 14:45:25 +020071 /* disable timer0 */
72 tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
73 __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
Alan Coxf4fabce2008-05-19 14:06:53 +010074 spin_unlock(&ks8695_lock);
Andrew Victorccb8f432007-05-14 14:45:25 +020075}
76
77/*
78 * Enable and reset the watchdog.
79 */
Alan Coxf4fabce2008-05-19 14:06:53 +010080static inline void ks8695_wdt_start(void)
Andrew Victorccb8f432007-05-14 14:45:25 +020081{
82 unsigned long tmcon;
Andrew Victor0a518102009-08-04 19:55:56 +010083 unsigned long tval = wdt_time * KS8695_CLOCK_RATE;
Andrew Victorccb8f432007-05-14 14:45:25 +020084
Alan Coxf4fabce2008-05-19 14:06:53 +010085 spin_lock(&ks8695_lock);
Andrew Victorccb8f432007-05-14 14:45:25 +020086 /* disable timer0 */
87 tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
88 __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
89
90 /* program timer0 */
91 __raw_writel(tval | T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC);
92
93 /* re-enable timer0 */
94 tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
95 __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
Alan Coxf4fabce2008-05-19 14:06:53 +010096 spin_unlock(&ks8695_lock);
Andrew Victorccb8f432007-05-14 14:45:25 +020097}
98
99/*
100 * Reload the watchdog timer. (ie, pat the watchdog)
101 */
Alan Coxf4fabce2008-05-19 14:06:53 +0100102static inline void ks8695_wdt_reload(void)
Andrew Victorccb8f432007-05-14 14:45:25 +0200103{
104 unsigned long tmcon;
105
Alan Coxf4fabce2008-05-19 14:06:53 +0100106 spin_lock(&ks8695_lock);
Andrew Victorccb8f432007-05-14 14:45:25 +0200107 /* disable, then re-enable timer0 */
108 tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
109 __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
110 __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
Alan Coxf4fabce2008-05-19 14:06:53 +0100111 spin_unlock(&ks8695_lock);
Andrew Victorccb8f432007-05-14 14:45:25 +0200112}
113
114/*
115 * Change the watchdog time interval.
116 */
117static int ks8695_wdt_settimeout(int new_time)
118{
119 /*
Andrew Victor0a518102009-08-04 19:55:56 +0100120 * All counting occurs at KS8695_CLOCK_RATE / 128 = 0.256 Hz
Andrew Victorccb8f432007-05-14 14:45:25 +0200121 *
122 * Since WDV is a 16-bit counter, the maximum period is
123 * 65536 / 0.256 = 256 seconds.
124 */
125 if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
126 return -EINVAL;
127
Alan Coxf4fabce2008-05-19 14:06:53 +0100128 /* Set new watchdog time. It will be used when
129 ks8695_wdt_start() is called. */
Andrew Victorccb8f432007-05-14 14:45:25 +0200130 wdt_time = new_time;
131 return 0;
132}
133
134/* ......................................................................... */
135
136/*
137 * Watchdog device is opened, and watchdog starts running.
138 */
139static int ks8695_wdt_open(struct inode *inode, struct file *file)
140{
141 if (test_and_set_bit(0, &ks8695wdt_busy))
142 return -EBUSY;
143
144 ks8695_wdt_start();
145 return nonseekable_open(inode, file);
146}
147
148/*
149 * Close the watchdog device.
150 * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
151 * disabled.
152 */
153static int ks8695_wdt_close(struct inode *inode, struct file *file)
154{
Alan Coxf4fabce2008-05-19 14:06:53 +0100155 /* Disable the watchdog when file is closed */
Andrew Victorccb8f432007-05-14 14:45:25 +0200156 if (!nowayout)
Alan Coxf4fabce2008-05-19 14:06:53 +0100157 ks8695_wdt_stop();
Andrew Victorccb8f432007-05-14 14:45:25 +0200158 clear_bit(0, &ks8695wdt_busy);
159 return 0;
160}
161
Wim Van Sebroeck42747d72009-12-26 18:55:22 +0000162static const struct watchdog_info ks8695_wdt_info = {
Andrew Victorccb8f432007-05-14 14:45:25 +0200163 .identity = "ks8695 watchdog",
164 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
165};
166
167/*
168 * Handle commands from user-space.
169 */
Alan Coxf4fabce2008-05-19 14:06:53 +0100170static long ks8695_wdt_ioctl(struct file *file, unsigned int cmd,
171 unsigned long arg)
Andrew Victorccb8f432007-05-14 14:45:25 +0200172{
173 void __user *argp = (void __user *)arg;
174 int __user *p = argp;
175 int new_value;
176
Alan Coxf4fabce2008-05-19 14:06:53 +0100177 switch (cmd) {
Alan Coxf4fabce2008-05-19 14:06:53 +0100178 case WDIOC_GETSUPPORT:
179 return copy_to_user(argp, &ks8695_wdt_info,
180 sizeof(ks8695_wdt_info)) ? -EFAULT : 0;
Alan Coxf4fabce2008-05-19 14:06:53 +0100181 case WDIOC_GETSTATUS:
182 case WDIOC_GETBOOTSTATUS:
183 return put_user(0, p);
184 case WDIOC_SETOPTIONS:
185 if (get_user(new_value, p))
186 return -EFAULT;
187 if (new_value & WDIOS_DISABLECARD)
188 ks8695_wdt_stop();
189 if (new_value & WDIOS_ENABLECARD)
Andrew Victorccb8f432007-05-14 14:45:25 +0200190 ks8695_wdt_start();
Alan Coxf4fabce2008-05-19 14:06:53 +0100191 return 0;
Wim Van Sebroeck0c06090c2008-07-18 11:41:17 +0000192 case WDIOC_KEEPALIVE:
193 ks8695_wdt_reload(); /* pat the watchdog */
194 return 0;
195 case WDIOC_SETTIMEOUT:
196 if (get_user(new_value, p))
197 return -EFAULT;
198 if (ks8695_wdt_settimeout(new_value))
199 return -EINVAL;
200 /* Enable new time value */
201 ks8695_wdt_start();
202 /* Return current value */
203 return put_user(wdt_time, p);
204 case WDIOC_GETTIMEOUT:
205 return put_user(wdt_time, p);
Alan Coxf4fabce2008-05-19 14:06:53 +0100206 default:
207 return -ENOTTY;
Andrew Victorccb8f432007-05-14 14:45:25 +0200208 }
209}
210
211/*
212 * Pat the watchdog whenever device is written to.
213 */
Alan Coxf4fabce2008-05-19 14:06:53 +0100214static ssize_t ks8695_wdt_write(struct file *file, const char *data,
215 size_t len, loff_t *ppos)
Andrew Victorccb8f432007-05-14 14:45:25 +0200216{
217 ks8695_wdt_reload(); /* pat the watchdog */
218 return len;
219}
220
221/* ......................................................................... */
222
223static const struct file_operations ks8695wdt_fops = {
224 .owner = THIS_MODULE,
225 .llseek = no_llseek,
Alan Coxf4fabce2008-05-19 14:06:53 +0100226 .unlocked_ioctl = ks8695_wdt_ioctl,
Andrew Victorccb8f432007-05-14 14:45:25 +0200227 .open = ks8695_wdt_open,
228 .release = ks8695_wdt_close,
229 .write = ks8695_wdt_write,
230};
231
232static struct miscdevice ks8695wdt_miscdev = {
233 .minor = WATCHDOG_MINOR,
234 .name = "watchdog",
235 .fops = &ks8695wdt_fops,
236};
237
Bill Pemberton2d991a12012-11-19 13:21:41 -0500238static int ks8695wdt_probe(struct platform_device *pdev)
Andrew Victorccb8f432007-05-14 14:45:25 +0200239{
240 int res;
241
242 if (ks8695wdt_miscdev.parent)
243 return -EBUSY;
244 ks8695wdt_miscdev.parent = &pdev->dev;
245
246 res = misc_register(&ks8695wdt_miscdev);
247 if (res)
248 return res;
249
Joe Perches27c766a2012-02-15 15:06:19 -0800250 pr_info("KS8695 Watchdog Timer enabled (%d seconds%s)\n",
251 wdt_time, nowayout ? ", nowayout" : "");
Andrew Victorccb8f432007-05-14 14:45:25 +0200252 return 0;
253}
254
Bill Pemberton4b12b892012-11-19 13:26:24 -0500255static int ks8695wdt_remove(struct platform_device *pdev)
Andrew Victorccb8f432007-05-14 14:45:25 +0200256{
257 int res;
258
259 res = misc_deregister(&ks8695wdt_miscdev);
260 if (!res)
261 ks8695wdt_miscdev.parent = NULL;
262
263 return res;
264}
265
266static void ks8695wdt_shutdown(struct platform_device *pdev)
267{
268 ks8695_wdt_stop();
269}
270
271#ifdef CONFIG_PM
272
273static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message)
274{
275 ks8695_wdt_stop();
276 return 0;
277}
278
279static int ks8695wdt_resume(struct platform_device *pdev)
280{
281 if (ks8695wdt_busy)
282 ks8695_wdt_start();
283 return 0;
284}
285
286#else
287#define ks8695wdt_suspend NULL
288#define ks8695wdt_resume NULL
289#endif
290
291static struct platform_driver ks8695wdt_driver = {
292 .probe = ks8695wdt_probe,
Bill Pemberton82268712012-11-19 13:21:12 -0500293 .remove = ks8695wdt_remove,
Andrew Victorccb8f432007-05-14 14:45:25 +0200294 .shutdown = ks8695wdt_shutdown,
295 .suspend = ks8695wdt_suspend,
296 .resume = ks8695wdt_resume,
297 .driver = {
298 .name = "ks8695_wdt",
299 .owner = THIS_MODULE,
300 },
301};
302
303static int __init ks8695_wdt_init(void)
304{
Alan Coxf4fabce2008-05-19 14:06:53 +0100305 /* Check that the heartbeat value is within range;
306 if not reset to the default */
Andrew Victorccb8f432007-05-14 14:45:25 +0200307 if (ks8695_wdt_settimeout(wdt_time)) {
308 ks8695_wdt_settimeout(WDT_DEFAULT_TIME);
Wim Van Sebroecka77dba72009-04-14 20:20:07 +0000309 pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i"
310 ", using %d\n", wdt_time, WDT_MAX_TIME);
Andrew Victorccb8f432007-05-14 14:45:25 +0200311 }
Andrew Victorccb8f432007-05-14 14:45:25 +0200312 return platform_driver_register(&ks8695wdt_driver);
313}
314
315static void __exit ks8695_wdt_exit(void)
316{
317 platform_driver_unregister(&ks8695wdt_driver);
318}
319
320module_init(ks8695_wdt_init);
321module_exit(ks8695_wdt_exit);
322
323MODULE_AUTHOR("Andrew Victor");
324MODULE_DESCRIPTION("Watchdog driver for KS8695");
325MODULE_LICENSE("GPL");
Kay Sieversf37d1932008-04-10 21:29:23 -0700326MODULE_ALIAS("platform:ks8695_wdt");