On 21.11.24 09:03, A. Sverdlin wrote:

From: Alexander Sverdlin alexander.sverdlin@siemens.com

The hack itself seems to be copied from Linux rti_wdt.c, but the WDT reset principle is different in U-Boot. While Linux relies on correct frequencies and timers and doesn't check the actual WDT counter value U-Boot driver seems to be more robust: it does compare RTIDWDCNTR vs RTIDWDPRLD.

Now the root cause of the original motivation to manipulate the clock rate is said to be understood and fixed in Linux commit cae58516534e ("watchdog: rti_wdt: Set min_hw_heartbeat_ms to accommodate a safety margin") which simultaneously removed the hack itself.

While is fix part of the mentioned patch is neither applicable nor requried for the U-Boot driver just drop the hack setting WDT clock rate to 90% of the real rate. This has a nice effect that the WDT timeout is now as requested and not 10% shorter.

Signed-off-by: Alexander Sverdlin alexander.sverdlin@siemens.com Reviewed-by: Jan Kiszka jan.kiszka@siemens.com

Applied to u-boot-watchdog/master

Thanks, Stefan

---

Changelog: v2: 2 typos pointed by Jan corrected

drivers/watchdog/rti_wdt.c | 8 -------- 1 file changed, 8 deletions(-)

diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c index 99168d0cad03..f806e24e53da 100644 --- a/drivers/watchdog/rti_wdt.c +++ b/drivers/watchdog/rti_wdt.c @@ -186,14 +186,6 @@ static int rti_wdt_probe(struct udevice *dev)

priv->clk_hz = clk_get_rate(&clk);

• /*

• * If watchdog is running at 32k clock, it is not accurate.
  

• * Adjust frequency down in this case so that it does not expire
  

• * earlier than expected.
  

• */
  

• if (priv->clk_hz < 32768)

• priv->clk_hz = priv->clk_hz * 9 / 10;
  

• return 0; }

Viele Grüße, Stefan Roese