[U-Boot] [PATCH 3/3] powerpc/mpc85xx: SECURE BOOT- Disable law 0 for non PBL platforms

[aneesh.bansal at freescale.com]

> > ISBC creates a LAW 0 entry for non PBL platforms, which is not
> > disabled before transferring the control to uboot.
> > The LAW 0 entry has to be disabled.
> >
> > Signed-off-by: Aneesh Bansal <aneesh.bansal at freescale.com>
> > ---
> >  arch/powerpc/cpu/mpc85xx/start.S | 58 ++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 58 insertions(+)
> >
> > diff --git a/arch/powerpc/cpu/mpc85xx/start.S b/arch/powerpc/cpu/mpc85xx/start.S
> > index 5440bf5..2b2c4dd 100644
> > --- a/arch/powerpc/cpu/mpc85xx/start.S
> > +++ b/arch/powerpc/cpu/mpc85xx/start.S
> > @@ -116,6 +116,64 @@ _start_e500:
> >       mtspr   SPRN_HDBCR0, r3
> >  #endif
> >
> > +#if defined(CONFIG_SECURE_BOOT) && defined(CONFIG_E500) && \
> > +                                             !defined(CONFIG_E500MC)
> 
> CONFIG_E500 can be assumed in this file.
> 
> > +     /* ISBC creates a LAW 0 entry for non PBL platforms,
> > +      * which is not disabled before transferring the control to uboot.
> > +      * Disable the LAW 0 entry here.
> > +      */
> 
> Could you explain what this LAW 0 entry is for, why we don't need it,
> and why we can't wait until later to clear it?
> 
> -Scott

Boot ROM creates a LAW 0 entry for IFC and at entry at U-boot during secure boot, we want to have the same environment as in case of Non-secure Boot. So, this LAW entry is being removed at start.

Regards,
Aneesh Bansal