[PATCH v5.1 9/7] watchdog: s3c2410: add restart handler

Heiko Stübner
2014-08-02T20:13:40Z

On a lot of Samsung systems the watchdog is responsible for restarting the
system and until now this code was contained in plat-samsung/watchdog-reset.c .

With the introduction of the restart handlers, this code can now move into
driver itself, removing the need for arch-specific code.

Tested on a S3C2442 based GTA02
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
[Guenter Roeck: Update to latest API; do not require static context variable]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Heiko Stuebner <heiko@sntech.de>
---
changes since v5:
- reintroduce the mdelay(500) from the platform code, to make sure the
watchdog has time to assert, as suggested by Tomasz Figa

drivers/watchdog/s3c2410_wdt.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)

diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
index 7c6ccd0..2955aef 100644
--- a/drivers/watchdog/s3c2410_wdt.c
+++ b/drivers/watchdog/s3c2410_wdt.c
@@ -41,6 +41,8 @@
#include <linux/of.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
+#include <linux/reboot.h>
+#include <linux/delay.h>

#define S3C2410_WTCON 0x00
#define S3C2410_WTDAT 0x04
@@ -128,6 +130,7 @@ struct s3c2410_wdt {
unsigned long wtdat_save;
struct watchdog_device wdt_device;
struct notifier_block freq_transition;
+ struct notifier_block restart_handler;
struct s3c2410_wdt_variant *drv_data;
struct regmap *pmureg;
};
@@ -438,6 +441,31 @@ static inline void s3c2410wdt_cpufreq_deregister(struct s3c2410_wdt *wdt)
}
#endif

+static int s3c2410wdt_restart(struct notifier_block *this,
+ unsigned long mode, void *cmd)
+{
+ struct s3c2410_wdt *wdt = container_of(this, struct s3c2410_wdt,
+ restart_handler);
+ void __iomem *wdt_base = wdt->reg_base;
+
+ /* disable watchdog, to be safe */
+ writel(0, wdt_base + S3C2410_WTCON);
+
+ /* put initial values into count and data */
+ writel(0x80, wdt_base + S3C2410_WTCNT);
+ writel(0x80, wdt_base + S3C2410_WTDAT);
+
+ /* set the watchdog to go and reset... */
+ writel(S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV16 |
+ S3C2410_WTCON_RSTEN | S3C2410_WTCON_PRESCALE(0x20),
+ wdt_base + S3C2410_WTCON);
+
+ /* wait for reset to assert... */
+ mdelay(500);
+
+ return NOTIFY_DONE;
+}
+
static inline unsigned int s3c2410wdt_get_bootstatus(struct s3c2410_wdt *wdt)
{
unsigned int rst_stat;
@@ -592,6 +620,12 @@ static int s3c2410wdt_probe(struct platform_device *pdev)

platform_set_drvdata(pdev, wdt);

+ wdt->restart_handler.notifier_call = s3c2410wdt_restart;
+ wdt->restart_handler.priority = 128;
+ ret = register_restart_handler(&wdt->restart_handler);
+ if (ret)
+ pr_err("cannot register restart handler, %d\n", ret);
+
/* print out a statement of readiness */

wtcon = readl(wdt->reg_base + S3C2410_WTCON);
@@ -621,6 +655,8 @@ static int s3c2410wdt_remove(struct platform_device *dev)
int ret;
struct s3c2410_wdt *wdt = platform_get_drvdata(dev);

+ unregister_restart_handler(&wdt->restart_handler);
+
ret = s3c2410wdt_mask_and_disable_reset(wdt, true);
if (ret < 0)
return ret;
--
2.0.1