[RFC 22/37] watchdog: renesas_wdt: Add restart support

[Fabrizio Castro]

This commit extends the driver to add restart support by implementing
the restart callback to trigger the watchdog as quickly as possible.

Signed-off-by: Fabrizio Castro <fabrizio.castro at bp.renesas.com>
Signed-off-by: Ramesh Shanmugasundaram <ramesh.shanmugasundaram at bp.renesas.com>
---
 drivers/watchdog/renesas_wdt.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c
index 831ef83..120ddac 100644
--- a/drivers/watchdog/renesas_wdt.c
+++ b/drivers/watchdog/renesas_wdt.c
@@ -107,6 +107,24 @@ static unsigned int rwdt_get_timeleft(struct watchdog_device *wdev)
 	return DIV_BY_CLKS_PER_SEC(priv, 65536 - val);
 }
 
+static int rwdt_restart(struct watchdog_device *wdev, unsigned long action,
+			void *data)
+{
+	struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
+
+	pm_runtime_get_sync(wdev->parent);
+
+	rwdt_write(priv, 0x00, RWTCSRB);
+	rwdt_write(priv, 0x00, RWTCSRA);
+	rwdt_write(priv, 0xffff, RWTCNT);
+
+	while (readb_relaxed(priv->base + RWTCSRA) & RWTCSRA_WRFLG)
+		cpu_relax();
+
+	rwdt_write(priv, 0x80, RWTCSRA);
+	return 0;
+}
+
 static const struct watchdog_info rwdt_ident = {
 	.options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
 	.identity = "Renesas WDT Watchdog",
@@ -118,6 +136,7 @@ static const struct watchdog_ops rwdt_ops = {
 	.stop = rwdt_stop,
 	.ping = rwdt_init_timeout,
 	.get_timeleft = rwdt_get_timeleft,
+	.restart = rwdt_restart,
 };
 
 static int rwdt_probe(struct platform_device *pdev)
-- 
2.7.4