From patchwork Fri Mar 13 16:04:58 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rasmus Villemoes X-Patchwork-Id: 243619 List-Id: U-Boot discussion From: rasmus.villemoes at prevas.dk (Rasmus Villemoes) Date: Fri, 13 Mar 2020 17:04:58 +0100 Subject: [PATCH 3/3] watchdog: honour hw_margin_ms DT property In-Reply-To: <20200313160458.19727-1-rasmus.villemoes@prevas.dk> References: <39e2b876-6ba1-59b6-4ddd-068e120f9b4e@denx.de> <20200313160458.19727-1-rasmus.villemoes@prevas.dk> Message-ID: <20200313160458.19727-4-rasmus.villemoes@prevas.dk> Some watchdog devices, e.g. external gpio-triggered ones, must be reset more often than once per second, which means that the current rate-limiting logic in watchdog_reset() fails to keep the board alive. gpio-wdt.txt in the linux source tree defines a "hw_margin_ms" property used to specifiy the maximum time allowed between resetting the device. Allow any watchdog device to specify such a property, and then use a reset period of one quarter of that. We keep the current default of resetting once every 1000ms. Signed-off-by: Rasmus Villemoes Reviewed-by: Stefan Roese --- drivers/watchdog/wdt-uclass.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/watchdog/wdt-uclass.c b/drivers/watchdog/wdt-uclass.c index fb3e247c5f..436a52fd08 100644 --- a/drivers/watchdog/wdt-uclass.c +++ b/drivers/watchdog/wdt-uclass.c @@ -15,6 +15,12 @@ DECLARE_GLOBAL_DATA_PTR; #define WATCHDOG_TIMEOUT_SECS (CONFIG_WATCHDOG_TIMEOUT_MSECS / 1000) +/* + * Reset every 1000ms, or however often is required as indicated by a + * hw_margin_ms property. + */ +static ulong reset_period = 1000; + int initr_watchdog(void) { u32 timeout = WATCHDOG_TIMEOUT_SECS; @@ -36,6 +42,8 @@ int initr_watchdog(void) if (CONFIG_IS_ENABLED(OF_CONTROL)) { timeout = dev_read_u32_default(gd->watchdog_dev, "timeout-sec", WATCHDOG_TIMEOUT_SECS); + reset_period = dev_read_u32_default(gd->watchdog_dev, "hw_margin_ms", + 4*reset_period)/4; } wdt_start(gd->watchdog_dev, timeout * 1000, 0); @@ -117,7 +125,7 @@ void watchdog_reset(void) /* Do not reset the watchdog too often */ now = get_timer(0); if (time_after(now, next_reset)) { - next_reset = now + 1000; /* reset every 1000ms */ + next_reset = now + reset_period; wdt_reset(gd->watchdog_dev); } }