watchdog: mediatek: Make sure system reset gets asserted in mtk_wdt_restart()

[ Upstream commit a1495a21e0b8aad92132dfcf9c6fffc1bde9d5b2 ]

Clear the IRQ enable bit of WDT_MODE before asserting software reset
in order to make TOPRGU issue a system reset signal instead of an IRQ.

Fixes: a44a45536f7b ("watchdog: Add driver for Mediatek watchdog")
Signed-off-by: Yassine Oudjana <y.oudjana@protonmail.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20241106104738.195968-2-y.oudjana@protonmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
index 796fbb048cbea9edfc926a18563969bcb0223ba8..a9d67ead9483809c28e22079c022795e5208dc86 100644 (file)
--- a/drivers/watchdog/mtk_wdt.c
+++ b/drivers/watchdog/mtk_wdt.c
@@ -164,9 +164,15 @@ static int mtk_wdt_restart(struct watchdog_device *wdt_dev,
 {
        struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
        void __iomem *wdt_base;
+       u32 reg;
 
        wdt_base = mtk_wdt->wdt_base;
 
+       /* Enable reset in order to issue a system reset instead of an IRQ */
+       reg = readl(wdt_base + WDT_MODE);
+       reg &= ~WDT_MODE_IRQ_EN;
+       writel(reg | WDT_MODE_KEY, wdt_base + WDT_MODE);
+
        while (1) {
                writel(WDT_SWRST_KEY, wdt_base + WDT_SWRST);
                mdelay(5);