Dear Alexander,
In message 201007220924.51614.alexander.stein@systec-electronic.com you wrote:
This is normal. Any watchdog that is worth the name will behave similar.
Well, I encountered several watchdog which start only after the first trigger.
Me too. They are ok in many applications, but completely unacceptable for advanced security requirements.
Of course, if CONFIG_HW_WATCHDOG and CONFIG_AT91SAM9_WATCHDOG is set, u-boot should use/trigger the watchdog. But (re-)programming the watchdog on AT91 is not _always_ necessary. Without programming (using CONFIG_SYS_WDTC_WDMR_VAL), the watchdog just runs with default settings, allowing e.g. Linux to reprogram it later. This patch allows to program the watchdog from u-boot, if wanted, but also allows to reprogram it later from Linux. While triggering the watchdog from u- boot itself does still work, wrt. the default watchdog settings.
I can see the intention, but this should not depend on "val" being defined or not - and it needs explicit documentation (in the README, for example).
Best regards,
Wolfgang Denk