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Subject[PATCH v2 2/2] watchdog: dw_wdt: add restart handler support
Date
The kernel core now provides an API to trigger a system restart.
Register with it to support restarting the system via. watchdog.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
---
drivers/watchdog/dw_wdt.c | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)

diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
index 449c885..9e577a6 100644
--- a/drivers/watchdog/dw_wdt.c
+++ b/drivers/watchdog/dw_wdt.c
@@ -21,6 +21,7 @@

#include <linux/bitops.h>
#include <linux/clk.h>
+#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/fs.h>
@@ -29,9 +30,11 @@
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
+#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/pm.h>
#include <linux/platform_device.h>
+#include <linux/reboot.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <linux/uaccess.h>
@@ -63,6 +66,7 @@ static struct {
unsigned long next_heartbeat;
struct timer_list timer;
int expect_close;
+ struct notifier_block restart_handler;
} dw_wdt;

static inline int dw_wdt_is_enabled(void)
@@ -121,6 +125,26 @@ static void dw_wdt_keepalive(void)
WDOG_COUNTER_RESTART_REG_OFFSET);
}

+static int dw_wdt_restart_handle(struct notifier_block *this,
+ unsigned long mode, void *cmd)
+{
+ u32 val;
+
+ writel(0, dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
+ val = readl(dw_wdt.regs + WDOG_CONTROL_REG_OFFSET);
+ if (val & WDOG_CONTROL_REG_WDT_EN_MASK)
+ writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt.regs +
+ WDOG_COUNTER_RESTART_REG_OFFSET);
+ else
+ writel(WDOG_CONTROL_REG_WDT_EN_MASK,
+ dw_wdt.regs + WDOG_CONTROL_REG_OFFSET);
+
+ /* wait for reset to assert... */
+ mdelay(500);
+
+ return NOTIFY_DONE;
+}
+
static void dw_wdt_ping(unsigned long data)
{
if (time_before(jiffies, dw_wdt.next_heartbeat) ||
@@ -316,6 +340,12 @@ static int dw_wdt_drv_probe(struct platform_device *pdev)
if (ret)
goto out_disable_clk;

+ dw_wdt.restart_handler.notifier_call = dw_wdt_restart_handle;
+ dw_wdt.restart_handler.priority = 128;
+ ret = register_restart_handler(&dw_wdt.restart_handler);
+ if (ret)
+ pr_warn("cannot register restart handler\n");
+
dw_wdt_set_next_heartbeat();
setup_timer(&dw_wdt.timer, dw_wdt_ping, 0);
mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT);
@@ -330,6 +360,8 @@ out_disable_clk:

static int dw_wdt_drv_remove(struct platform_device *pdev)
{
+ unregister_restart_handler(&dw_wdt.restart_handler);
+
misc_deregister(&dw_wdt_miscdev);

clk_disable_unprepare(dw_wdt.clk);
--
2.1.0


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