diff options
| author | Jacky Bai <ping.bai@nxp.com> | 2022-08-25 16:32:51 +0800 |
|---|---|---|
| committer | Wim Van Sebroeck <wim@linux-watchdog.org> | 2022-10-02 12:55:44 +0200 |
| commit | 6371593fbad75cfb9ee14e8b462a5ebb1aa38c02 (patch) | |
| tree | 2567f47141eaf5e5925bac663127cca15cd43172 /drivers/watchdog | |
| parent | f182683333b5d8ac4af64517b6e3c444c4579e6e (diff) | |
| download | linux-6371593fbad75cfb9ee14e8b462a5ebb1aa38c02.tar.bz2 | |
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 <ye.li@nxp.com>
Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Signed-off-by: Alice Guo <alice.guo@nxp.com>
Reviewed-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220825083256.14565-3-alice.guo@oss.nxp.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Diffstat (limited to 'drivers/watchdog')
| -rw-r--r-- | drivers/watchdog/imx7ulp_wdt.c | 4 |
1 files changed, 4 insertions, 0 deletions
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; |