Re: [PATCH u-boot v2 1/2] drivers: spi: Add support for disabling FMC_WDT2 for aspeed

Ivan Mikhaylov
2026-01-06T14:53:47Z

On Tue, Jan 6, 2026 at 3:05 AM Marc Olberding <molberding@nvidia.com> wrote:
>
> On Sat, Jan 03, 2026 at 12:24:07AM +0300, Иван Михайлов wrote:
> > On Wed, Dec 3, 2025 at 2:53 AM Marc Olberding <molberding@nvidia.com> wrote:
> > >
> > > Adds support for disabling the ast2600 FMC_WDT2 through
> > > a device tree entry in the fmc node.
> > > Set `aspeed,watchdog-disable` in your device tree to have
> > > the driver disable it.
> >
> > Marc, FMC_WDT2 doesn't disable watchdog, it controls ABR mode.
> > Watchdog with or without ABR still in operational mode.
> > So, maybe aspeed,abr-disable?
> >
> > Below namings probably should be corrected.
> We aren't disabling ABR mode with this change, right? That's only
> done through hardware straps or OTP changes. All this is doing is clearing bit 0
> of FMC64, which per the datasheet disables the watchdog. The idea here is
> to just allow boot to progress normally, without the watchdog. For ping pong update,
> userspace can flash the alternative SPI and re-enable the watchdog timer on complete,
> and the BMC will boot from the new image upon reset. Let me know if I'm misunderstanding
> your comment.
>

Marc, when you clrbits_le on FMC64/FMC_WDT2, then you disable ABR mode, I
assume you can check it with evb board or ast2600-a3 to prove. On my board
ast2600-a3 it works in that way I described with enabled OTP strap for ABR.

Also description of it in 14.2.2 Alternative Boot Recovery Function.

FMC_WDT2 & WDT2 as far as I know are different, you're not disabling
WDT2 with disabling FMC_WDT2.

According to the spec, it's right it disables/enables the watchdog with 0 bit
but which one. Probably FMC_WDT2, not WDT2, and it still works as should and
disabling WDT2/WDTX in different sections - WDT0C 0 bit and WDT30.

Thanks.