Re: [PATCH 4/5] board: nxp: imx9{4,5}_evk: Add qb save option in SPL

[Francesco Dolcini <francesco@dolcini.it>]

On Tue, Mar 10, 2026 at 05:27:45PM +0200, Simona Toaca wrote:
> On Tue, Mar 10, 2026 at 04:04:19PM +0100, Emanuele Ghidoli wrote:
> > On 3/10/26 12:54, Simona Toaca (OSS) wrote:
> > > From: Simona Toaca <simona.toaca@nxp.com>
> > > 
> > > Call qb save automatically in the board-specific
> > > spl_board_init(), if SPL_QB option is enabled. This
> > > makes sure qb_save is called before any image loading
> > > is done by the SPL.
> > > 
> > > Signed-off-by: Simona Toaca <simona.toaca@nxp.com>

...

> > > diff --git a/board/nxp/imx94_evk/spl.c b/board/nxp/imx94_evk/spl.c
> > > index cc5b7f9ef0f..1d25795eb17 100644
> > > --- a/board/nxp/imx94_evk/spl.c
> > > +++ b/board/nxp/imx94_evk/spl.c
> > > @@ -44,6 +45,9 @@ void spl_board_init(void)
> > >  	ret = ele_start_rng();
> > >  	if (ret)
> > >  		printf("Fail to start RNG: %d\n", ret);
> > > +
> > > +	if (IS_ENABLED(CONFIG_SPL_IMX_QB))
> > > +		spl_qb_save();
> > Does it write to MMC/NOR/SD at every boot? Is that necessary if a quick boot
> > was performed and the data has not changed?
> > >  }
> No, the qb() method calls qb_check, which returns true only if OEI
> saved valid data to volatile memory (meaning it has run Training flow).
> So, if Quickboot flow is run, the data in volatile memory is not valid,
> qb_check fails -> qb returns and does not write anything to the NVM.
> 
> Also, another thing to keep in mind is that after a successfull
> qb save, the data in volatile memory is invalidated -> qb check will
> fail as well even if OEI doesn't run (so on a warm reboot).

Do you think that this is something that should be generally enabled on
any i.MX95 boards? Emanuele?

Francesco