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watchdog: at91rm9200: implement restart handler 

Restarting the at91rm9200 is done through programming the watchdog and waiting
for it to reset.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
This commit is contained in:
Alexandre Belloni 2015-03-12 13:07:28 +01:00 committed by Nicolas Ferre
parent 8432f9e5e8
commit 9ab45f3fb2
1 changed files with 32 additions and 0 deletions
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32
drivers/watchdog/at91rm9200_wdt.c
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@ -12,6 +12,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
@ -23,6 +24,7 @@
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/regmap.h>
#include <linux/types.h>
#include <linux/watchdog.h>
@ -53,6 +55,27 @@ static unsigned long at91wdt_busy;
/* ......................................................................... */
static int at91rm9200_restart(struct notifier_block *this,
unsigned long mode, void *cmd)
{
/*
* Perform a hardware reset with the use of the Watchdog timer.
*/
regmap_write(regmap_st, AT91_ST_WDMR,
AT91_ST_RSTEN | AT91_ST_EXTEN | 1);
regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
mdelay(2000);
pr_emerg("Unable to restart system\n");
return NOTIFY_DONE;
}
static struct notifier_block at91rm9200_restart_nb = {
.notifier_call = at91rm9200_restart,
.priority = 192,
};
/*
* Disable the watchdog.
*/
@ -228,6 +251,10 @@ static int at91wdt_probe(struct platform_device *pdev)
if (res)
return res;
res = register_restart_handler(&at91rm9200_restart_nb);
if (res)
dev_warn(dev, "failed to register restart handler\n");
pr_info("AT91 Watchdog Timer enabled (%d seconds%s)\n",
wdt_time, nowayout ? ", nowayout" : "");
return 0;
@ -235,8 +262,13 @@ static int at91wdt_probe(struct platform_device *pdev)
static int at91wdt_remove(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
int res;
res = unregister_restart_handler(&at91rm9200_restart_nb);
if (res)
dev_warn(dev, "failed to unregister restart handler\n");
res = misc_deregister(&at91wdt_miscdev);
if (!res)
at91wdt_miscdev.parent = NULL;