Dear Wolfgang Denk, Am Donnerstag, 22. Juli 2010, 09:09:12 schrieb Wolfgang Denk: > > Well, my problem is, that CONFIG_SYS_WDTC_WDMR_VAL is used to program the > > internal watchdog. But this watchdog can only be programmed once until a > > reset occurs. So there is no possibility for linux to reprogram it. > > 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. > > So, if CONFIG_SYS_WDTC_WDMR_VAL is not defined and the watchdog is not > > programed using my patch, the watchdog still runs with default settings > > (timeout of 16s). So a user may choose to trigger the watchdog from > > u-boot (define CONFIG_AT91SAM9_WATCHDOG and CONFIG_HW_WATCHDOG) or let > > it run silently. To summarize, CONFIG_SYS_WDTC_WDMR_VAL is not needed to > > use CONFIG_AT91SAM9_WATCHDOG and CONFIG_HW_WATCHDOG. > > Then the subject is misleading - it suggests you do not initialize / > let run the watchdog at all if CONFIG_SYS_WDTC_WDMR_VAL is undefined. Ok, maybe the subject need some rework. > I think we should make sure that everything is in a sane and > consistent state - if CONFIG_HW_WATCHDOG (and > CONFIG_AT91SAM9_WATCHDOG) are set, this indicates that U-Boot is > supposed to use the watchdog, which in turn means they should > initialize it. 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. Best regards, Alexander Stein _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot