[PATCH v5 04/10] watchdog: at91rm9200: implement restart handler

Alexandre Belloni
2015-03-12T12:08:14Z

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>
---
drivers/watchdog/at91rm9200_wdt.c | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)

diff --git a/drivers/watchdog/at91rm9200_wdt.c b/drivers/watchdog/at91rm9200_wdt.c
index e6fa87d85de3..41cecb55766c 100644
--- a/drivers/watchdog/at91rm9200_wdt.c
+++ b/drivers/watchdog/at91rm9200_wdt.c
@@ -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;
--
2.1.0