watchdog: rzg2l_wdt: Use force reset for WDT reset

This patch uses the force reset(WDTRSTB) for triggering WDT reset for
restart callback. This method(ie, Generate Reset (WDTRSTB) Signal on
parity error)is faster compared to the overflow method for triggering
watchdog reset.

Overflow method:
	reboot: Restarting system
	Reboot failed -- System halted
	NOTICE:  BL2: v2.5(release):v2.5/rzg2l-1.00-27-gf48f1440c

Parity error method:
	reboot: Restarting system
	NOTICE:  BL2: v2.5(release):v2.5/rzg2l-1.00-27-gf48f1440c

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220225175320.11041-7-biju.das.jz@bp.renesas.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

diff --git a/drivers/watchdog/rzg2l_wdt.c b/drivers/watchdog/rzg2l_wdt.c
index 73b667e..4e71076 100644 (file)
--- a/drivers/watchdog/rzg2l_wdt.c
+++ b/drivers/watchdog/rzg2l_wdt.c
@@ -21,8 +21,11 @@
 #define WDTSET         0x04
 #define WDTTIM         0x08
 #define WDTINT         0x0C
+#define PECR           0x10
+#define PEEN           0x14
 #define WDTCNT_WDTEN   BIT(0)
 #define WDTINT_INTDISP BIT(0)
+#define PEEN_FORCE     BIT(0)
 
 #define WDT_DEFAULT_TIMEOUT            60U
 
@@ -117,17 +120,14 @@ static int rzg2l_wdt_restart(struct watchdog_device *wdev,
 {
        struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
 
-       /* Reset the module before we modify any register */
-       reset_control_reset(priv->rstc);
-
        clk_prepare_enable(priv->pclk);
        clk_prepare_enable(priv->osc_clk);
 
-       /* smallest counter value to reboot soon */
-       rzg2l_wdt_write(priv, WDTSET_COUNTER_VAL(1), WDTSET);
+       /* Generate Reset (WDTRSTB) Signal on parity error */
+       rzg2l_wdt_write(priv, 0, PECR);
 
-       /* Enable watchdog timer*/
-       rzg2l_wdt_write(priv, WDTCNT_WDTEN, WDTCNT);
+       /* Force parity error */
+       rzg2l_wdt_write(priv, PEEN_FORCE, PEEN);
 
        return 0;
 }