From 6371593fbad75cfb9ee14e8b462a5ebb1aa38c02 Mon Sep 17 00:00:00 2001 From: Jacky Bai Date: Thu, 25 Aug 2022 16:32:51 +0800 Subject: watchdog: imx7ulp: Add explict memory barrier for unlock sequence When reconfiguring the WDOG Timer of i.MX7ULP, there is a certain probability causes it to reset. The reason is that the CMD32EN of the WDOG Timer of i.MX7ULP is disabled in bootloader. The unlock sequence are two 16-bit writes to the CNT register within 16 bus clocks. Adding mb() is to guarantee that two 16-bit writes are finished within 16 bus clocks. Memory barriers cannot be added between these two 16-bit writes so that writel_relaxed is used. Suggested-by: Ye Li Signed-off-by: Jacky Bai Signed-off-by: Alice Guo Reviewed-by: Ye Li Reviewed-by: Guenter Roeck Link: https://lore.kernel.org/r/20220825083256.14565-3-alice.guo@oss.nxp.com Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck --- drivers/watchdog/imx7ulp_wdt.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'drivers/watchdog') diff --git a/drivers/watchdog/imx7ulp_wdt.c b/drivers/watchdog/imx7ulp_wdt.c index 014f497ea0dc..b8ac0cb04d2f 100644 --- a/drivers/watchdog/imx7ulp_wdt.c +++ b/drivers/watchdog/imx7ulp_wdt.c @@ -179,9 +179,13 @@ static int imx7ulp_wdt_init(void __iomem *base, unsigned int timeout) int ret; local_irq_disable(); + + mb(); /* unlock the wdog for reconfiguration */ writel_relaxed(UNLOCK_SEQ0, base + WDOG_CNT); writel_relaxed(UNLOCK_SEQ1, base + WDOG_CNT); + mb(); + ret = imx7ulp_wdt_wait(base, WDOG_CS_ULK); if (ret) goto init_out; -- cgit v1.2.3