1 /* linux/drivers/char/watchdog/s3c2410_wdt.c
3 * Copyright (c) 2004 Simtec Electronics
4 * Ben Dooks <ben@simtec.co.uk>
6 * S3C2410 Watchdog Timer Support
8 * Based on, softdog.c by Alan Cox,
9 * (c) Copyright 1996 Alan Cox <alan@redhat.com>
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
26 * 05-Oct-2004 BJD Added semaphore init to stop crashes on open
27 * Fixed tmr_count / wdt_count confusion
28 * Added configurable debug
30 * 11-Jan-2005 BJD Fixed divide-by-2 in timeout code
32 * 25-Jan-2005 DA Added suspend/resume support
33 * Replaced reboot notifier with .shutdown method
35 * 10-Mar-2005 LCVR Changed S3C2410_VA to S3C24XX_VA
38 #include <linux/module.h>
39 #include <linux/moduleparam.h>
40 #include <linux/types.h>
41 #include <linux/timer.h>
42 #include <linux/miscdevice.h>
43 #include <linux/watchdog.h>
45 #include <linux/init.h>
46 #include <linux/platform_device.h>
47 #include <linux/interrupt.h>
48 #include <linux/clk.h>
49 #include <linux/uaccess.h>
54 #undef S3C_VA_WATCHDOG
55 #define S3C_VA_WATCHDOG (0)
57 #include <asm/plat-s3c/regs-watchdog.h>
59 #define PFX "s3c2410-wdt: "
61 #define CONFIG_S3C2410_WATCHDOG_ATBOOT (0)
62 #define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME (15)
64 static int nowayout
= WATCHDOG_NOWAYOUT
;
65 static int tmr_margin
= CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME
;
66 static int tmr_atboot
= CONFIG_S3C2410_WATCHDOG_ATBOOT
;
67 static int soft_noboot
;
70 module_param(tmr_margin
, int, 0);
71 module_param(tmr_atboot
, int, 0);
72 module_param(nowayout
, int, 0);
73 module_param(soft_noboot
, int, 0);
74 module_param(debug
, int, 0);
76 MODULE_PARM_DESC(tmr_margin
, "Watchdog tmr_margin in seconds. default="
77 __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME
) ")");
78 MODULE_PARM_DESC(tmr_atboot
,
79 "Watchdog is started at boot time if set to 1, default="
80 __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT
));
81 MODULE_PARM_DESC(nowayout
, "Watchdog cannot be stopped once started (default="
82 __MODULE_STRING(WATCHDOG_NOWAYOUT
) ")");
83 MODULE_PARM_DESC(soft_noboot
, "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default depends on ONLY_TESTING)");
84 MODULE_PARM_DESC(debug
, "Watchdog debug, set to >1 for debug, (default 0)");
87 typedef enum close_state
{
89 CLOSE_STATE_ALLOW
= 0x4021
92 static unsigned long open_lock
;
93 static struct device
*wdt_dev
; /* platform device attached to */
94 static struct resource
*wdt_mem
;
95 static struct resource
*wdt_irq
;
96 static struct clk
*wdt_clock
;
97 static void __iomem
*wdt_base
;
98 static unsigned int wdt_count
;
99 static close_state_t allow_close
;
100 static DEFINE_SPINLOCK(wdt_lock
);
102 /* watchdog control routines */
104 #define DBG(msg...) do { \
106 printk(KERN_INFO msg); \
111 static void s3c2410wdt_keepalive(void)
113 spin_lock(&wdt_lock
);
114 writel(wdt_count
, wdt_base
+ S3C2410_WTCNT
);
115 spin_unlock(&wdt_lock
);
118 static void __s3c2410wdt_stop(void)
122 wtcon
= readl(wdt_base
+ S3C2410_WTCON
);
123 wtcon
&= ~(S3C2410_WTCON_ENABLE
| S3C2410_WTCON_RSTEN
);
124 writel(wtcon
, wdt_base
+ S3C2410_WTCON
);
127 static void s3c2410wdt_stop(void)
129 spin_lock(&wdt_lock
);
131 spin_unlock(&wdt_lock
);
134 static void s3c2410wdt_start(void)
138 spin_lock(&wdt_lock
);
142 wtcon
= readl(wdt_base
+ S3C2410_WTCON
);
143 wtcon
|= S3C2410_WTCON_ENABLE
| S3C2410_WTCON_DIV128
;
146 wtcon
|= S3C2410_WTCON_INTEN
;
147 wtcon
&= ~S3C2410_WTCON_RSTEN
;
149 wtcon
&= ~S3C2410_WTCON_INTEN
;
150 wtcon
|= S3C2410_WTCON_RSTEN
;
153 DBG("%s: wdt_count=0x%08x, wtcon=%08lx\n",
154 __func__
, wdt_count
, wtcon
);
156 writel(wdt_count
, wdt_base
+ S3C2410_WTDAT
);
157 writel(wdt_count
, wdt_base
+ S3C2410_WTCNT
);
158 writel(wtcon
, wdt_base
+ S3C2410_WTCON
);
159 spin_unlock(&wdt_lock
);
162 static int s3c2410wdt_set_heartbeat(int timeout
)
164 unsigned int freq
= clk_get_rate(wdt_clock
);
166 unsigned int divisor
= 1;
173 count
= timeout
* freq
;
175 DBG("%s: count=%d, timeout=%d, freq=%d\n",
176 __func__
, count
, timeout
, freq
);
178 /* if the count is bigger than the watchdog register,
179 then work out what we need to do (and if) we can
180 actually make this value
183 if (count
>= 0x10000) {
184 for (divisor
= 1; divisor
<= 0x100; divisor
++) {
185 if ((count
/ divisor
) < 0x10000)
189 if ((count
/ divisor
) >= 0x10000) {
190 dev_err(wdt_dev
, "timeout %d too big\n", timeout
);
195 tmr_margin
= timeout
;
197 DBG("%s: timeout=%d, divisor=%d, count=%d (%08x)\n",
198 __func__
, timeout
, divisor
, count
, count
/divisor
);
203 /* update the pre-scaler */
204 wtcon
= readl(wdt_base
+ S3C2410_WTCON
);
205 wtcon
&= ~S3C2410_WTCON_PRESCALE_MASK
;
206 wtcon
|= S3C2410_WTCON_PRESCALE(divisor
-1);
208 writel(count
, wdt_base
+ S3C2410_WTDAT
);
209 writel(wtcon
, wdt_base
+ S3C2410_WTCON
);
215 * /dev/watchdog handling
218 static int s3c2410wdt_open(struct inode
*inode
, struct file
*file
)
220 if (test_and_set_bit(0, &open_lock
))
224 __module_get(THIS_MODULE
);
226 allow_close
= CLOSE_STATE_NOT
;
228 /* start the timer */
230 return nonseekable_open(inode
, file
);
233 static int s3c2410wdt_release(struct inode
*inode
, struct file
*file
)
236 * Shut off the timer.
237 * Lock it in if it's a module and we set nowayout
240 if (allow_close
== CLOSE_STATE_ALLOW
)
243 dev_err(wdt_dev
, "Unexpected close, not stopping watchdog\n");
244 s3c2410wdt_keepalive();
246 allow_close
= CLOSE_STATE_NOT
;
247 clear_bit(0, &open_lock
);
251 static ssize_t
s3c2410wdt_write(struct file
*file
, const char __user
*data
,
252 size_t len
, loff_t
*ppos
)
261 /* In case it was set long ago */
262 allow_close
= CLOSE_STATE_NOT
;
264 for (i
= 0; i
!= len
; i
++) {
267 if (get_user(c
, data
+ i
))
270 allow_close
= CLOSE_STATE_ALLOW
;
273 s3c2410wdt_keepalive();
278 #define OPTIONS WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE
280 static const struct watchdog_info s3c2410_wdt_ident
= {
282 .firmware_version
= 0,
283 .identity
= "S3C2410 Watchdog",
287 static long s3c2410wdt_ioctl(struct file
*file
, unsigned int cmd
,
290 void __user
*argp
= (void __user
*)arg
;
291 int __user
*p
= argp
;
295 case WDIOC_GETSUPPORT
:
296 return copy_to_user(argp
, &s3c2410_wdt_ident
,
297 sizeof(s3c2410_wdt_ident
)) ? -EFAULT
: 0;
298 case WDIOC_GETSTATUS
:
299 case WDIOC_GETBOOTSTATUS
:
300 return put_user(0, p
);
301 case WDIOC_KEEPALIVE
:
302 s3c2410wdt_keepalive();
304 case WDIOC_SETTIMEOUT
:
305 if (get_user(new_margin
, p
))
307 if (s3c2410wdt_set_heartbeat(new_margin
))
309 s3c2410wdt_keepalive();
310 return put_user(tmr_margin
, p
);
311 case WDIOC_GETTIMEOUT
:
312 return put_user(tmr_margin
, p
);
318 /* kernel interface */
320 static const struct file_operations s3c2410wdt_fops
= {
321 .owner
= THIS_MODULE
,
323 .write
= s3c2410wdt_write
,
324 .unlocked_ioctl
= s3c2410wdt_ioctl
,
325 .open
= s3c2410wdt_open
,
326 .release
= s3c2410wdt_release
,
329 static struct miscdevice s3c2410wdt_miscdev
= {
330 .minor
= WATCHDOG_MINOR
,
332 .fops
= &s3c2410wdt_fops
,
335 /* interrupt handler code */
337 static irqreturn_t
s3c2410wdt_irq(int irqno
, void *param
)
339 dev_info(wdt_dev
, "watchdog timer expired (irq)\n");
341 s3c2410wdt_keepalive();
344 /* device interface */
346 static int s3c2410wdt_probe(struct platform_device
*pdev
)
348 struct resource
*res
;
355 DBG("%s: probe=%p\n", __func__
, pdev
);
358 wdt_dev
= &pdev
->dev
;
360 /* get the memory region for the watchdog timer */
362 res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
364 dev_err(dev
, "no memory resource specified\n");
368 size
= (res
->end
-res
->start
)+1;
369 wdt_mem
= request_mem_region(res
->start
, size
, pdev
->name
);
370 if (wdt_mem
== NULL
) {
371 dev_err(dev
, "failed to get memory region\n");
376 wdt_base
= ioremap(res
->start
, size
);
378 dev_err(dev
, "failed to ioremap() region\n");
383 DBG("probe: mapped wdt_base=%p\n", wdt_base
);
385 wdt_irq
= platform_get_resource(pdev
, IORESOURCE_IRQ
, 0);
386 if (wdt_irq
== NULL
) {
387 dev_err(dev
, "no irq resource specified\n");
392 ret
= request_irq(wdt_irq
->start
, s3c2410wdt_irq
, 0, pdev
->name
, pdev
);
394 dev_err(dev
, "failed to install irq (%d)\n", ret
);
398 wdt_clock
= clk_get(&pdev
->dev
, "watchdog");
399 if (IS_ERR(wdt_clock
)) {
400 dev_err(dev
, "failed to find watchdog clock source\n");
401 ret
= PTR_ERR(wdt_clock
);
405 clk_enable(wdt_clock
);
407 /* see if we can actually set the requested timer margin, and if
408 * not, try the default value */
410 if (s3c2410wdt_set_heartbeat(tmr_margin
)) {
411 started
= s3c2410wdt_set_heartbeat(
412 CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME
);
416 "tmr_margin value out of range, default %d used\n",
417 CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME
);
419 dev_info(dev
, "default timer value is out of range, cannot start\n");
422 ret
= misc_register(&s3c2410wdt_miscdev
);
424 dev_err(dev
, "cannot register miscdev on minor=%d (%d)\n",
425 WATCHDOG_MINOR
, ret
);
429 if (tmr_atboot
&& started
== 0) {
430 dev_info(dev
, "starting watchdog timer\n");
432 } else if (!tmr_atboot
) {
433 /* if we're not enabling the watchdog, then ensure it is
434 * disabled if it has been left running from the bootloader
440 /* print out a statement of readiness */
442 wtcon
= readl(wdt_base
+ S3C2410_WTCON
);
444 dev_info(dev
, "watchdog %sactive, reset %sabled, irq %sabled\n",
445 (wtcon
& S3C2410_WTCON_ENABLE
) ? "" : "in",
446 (wtcon
& S3C2410_WTCON_RSTEN
) ? "" : "dis",
447 (wtcon
& S3C2410_WTCON_INTEN
) ? "" : "en");
452 clk_disable(wdt_clock
);
456 free_irq(wdt_irq
->start
, pdev
);
462 release_resource(wdt_mem
);
468 static int s3c2410wdt_remove(struct platform_device
*dev
)
470 release_resource(wdt_mem
);
474 free_irq(wdt_irq
->start
, dev
);
477 clk_disable(wdt_clock
);
482 misc_deregister(&s3c2410wdt_miscdev
);
486 static void s3c2410wdt_shutdown(struct platform_device
*dev
)
493 static unsigned long wtcon_save
;
494 static unsigned long wtdat_save
;
496 static int s3c2410wdt_suspend(struct platform_device
*dev
, pm_message_t state
)
498 /* Save watchdog state, and turn it off. */
499 wtcon_save
= readl(wdt_base
+ S3C2410_WTCON
);
500 wtdat_save
= readl(wdt_base
+ S3C2410_WTDAT
);
502 /* Note that WTCNT doesn't need to be saved. */
508 static int s3c2410wdt_resume(struct platform_device
*dev
)
510 /* Restore watchdog state. */
512 writel(wtdat_save
, wdt_base
+ S3C2410_WTDAT
);
513 writel(wtdat_save
, wdt_base
+ S3C2410_WTCNT
); /* Reset count */
514 writel(wtcon_save
, wdt_base
+ S3C2410_WTCON
);
516 printk(KERN_INFO PFX
"watchdog %sabled\n",
517 (wtcon_save
& S3C2410_WTCON_ENABLE
) ? "en" : "dis");
523 #define s3c2410wdt_suspend NULL
524 #define s3c2410wdt_resume NULL
525 #endif /* CONFIG_PM */
528 static struct platform_driver s3c2410wdt_driver
= {
529 .probe
= s3c2410wdt_probe
,
530 .remove
= s3c2410wdt_remove
,
531 .shutdown
= s3c2410wdt_shutdown
,
532 .suspend
= s3c2410wdt_suspend
,
533 .resume
= s3c2410wdt_resume
,
535 .owner
= THIS_MODULE
,
536 .name
= "s3c2410-wdt",
541 static char banner
[] __initdata
=
542 KERN_INFO
"S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";
544 static int __init
watchdog_init(void)
547 return platform_driver_register(&s3c2410wdt_driver
);
550 static void __exit
watchdog_exit(void)
552 platform_driver_unregister(&s3c2410wdt_driver
);
555 module_init(watchdog_init
);
556 module_exit(watchdog_exit
);
558 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, "
559 "Dimitry Andric <dimitry.andric@tomtom.com>");
560 MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
561 MODULE_LICENSE("GPL");
562 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR
);
563 MODULE_ALIAS("platform:s3c2410-wdt");