Re: [PATCH 4/7] watchdog: imx7ulp_wdt: Fix RCS timeout issue

From: Guenter Roeck
Date: Mon Aug 22 2022 - 10:09:54 EST


On Tue, Aug 16, 2022 at 12:36:40PM +0800, Alice Guo (OSS) wrote:
> From: Ye Li <ye.li@xxxxxxx>
>
> According to measure on i.MX7ULP and i.MX8ULP, the RCS done needs
> about 3400us and 6700us respectively. So current 20us timeout is
> not enough. When reconfiguring is on-going, unlock and configure CS
> will lead to unknown result.
>
> Increase the wait timeout value to 10ms and check the return value
> of RCS wait to fix the issue
>

You'll have to find a better solution. An active (non-sleep) wait of
10 ms is unacceptable.

Guenter

> Signed-off-by: Ye Li <ye.li@xxxxxxx>
> Signed-off-by: Alice Guo <alice.guo@xxxxxxx>
> Reviewed-by: Jacky Bai <ping.bai@xxxxxxx>
> Acked-by: Jason Liu <jason.hui.liu@xxxxxxx>
> ---
> drivers/watchdog/imx7ulp_wdt.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/watchdog/imx7ulp_wdt.c b/drivers/watchdog/imx7ulp_wdt.c
> index a0f6b8cea78f..12715c248688 100644
> --- a/drivers/watchdog/imx7ulp_wdt.c
> +++ b/drivers/watchdog/imx7ulp_wdt.c
> @@ -39,7 +39,7 @@
> #define DEFAULT_TIMEOUT 60
> #define MAX_TIMEOUT 128
> #define WDOG_CLOCK_RATE 1000
> -#define WDOG_WAIT_TIMEOUT 20
> +#define WDOG_WAIT_TIMEOUT 10000
>
> static bool nowayout = WATCHDOG_NOWAYOUT;
> module_param(nowayout, bool, 0000);
> @@ -80,7 +80,7 @@ static int imx7ulp_wdt_enable(struct watchdog_device *wdog, bool enable)
> writel(val | WDOG_CS_EN, wdt->base + WDOG_CS);
> else
> writel(val & ~WDOG_CS_EN, wdt->base + WDOG_CS);
> - imx7ulp_wdt_wait(wdt->base, WDOG_CS_RCS);
> + ret = imx7ulp_wdt_wait(wdt->base, WDOG_CS_RCS);
>
> enable_out:
> local_irq_enable();
> @@ -127,7 +127,9 @@ static int imx7ulp_wdt_set_timeout(struct watchdog_device *wdog,
> if (ret)
> goto timeout_out;
> writel(val, wdt->base + WDOG_TOVAL);
> - imx7ulp_wdt_wait(wdt->base, WDOG_CS_RCS);
> + ret = imx7ulp_wdt_wait(wdt->base, WDOG_CS_RCS);
> + if (ret)
> + goto timeout_out;
>
> wdog->timeout = timeout;
>
> --
> 2.17.1
>