Re: [PATCH 4/4] board: vexpress64: enable bloblist for SPL handoff

[Tom Rini <trini@konsulko.com>]

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On Thu, Dec 19, 2024 at 04:04:04PM +0000, Harrison Mutai wrote:
> On 18/12/2024 16:31, Tom Rini wrote:
> > On Wed, Dec 18, 2024 at 03:39:31PM +0000, Harrison Mutai wrote:
> > 
> > > Enable bloblist on vexpress64 platforms to facilitate information
> > > passing from TF-A using the firmware handoff framework.
> > > 
> > > Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
> > [snip]
> > > diff --git a/configs/vexpress_fvp_bloblist_defconfig b/configs/vexpress_fvp_bloblist_defconfig
> > > new file mode 100644
> > > index 0000000000..dcc87db872
> > > --- /dev/null
> > > +++ b/configs/vexpress_fvp_bloblist_defconfig
> > > @@ -0,0 +1,5 @@
> > > +#include <configs/vexpress_fvp_defconfig>
> > > +
> > > +CONFIG_BLOBLIST=y
> > > +CONFIG_BLOBLIST_PASSAGE=y
> > > +CONFIG_BLOBLIST_SIZE_RELOC=0x10000
> > 
> > I wonder if this means we should also do:
> > 
> > diff --git a/common/Kconfig b/common/Kconfig
> > index 11066ec64315..cca33ed28f32 100644
> > --- a/common/Kconfig
> > +++ b/common/Kconfig
> > @@ -1087,7 +1087,6 @@ config BLOBLIST_SIZE
> >   config BLOBLIST_SIZE_RELOC
> >   	hex "Size of bloblist after relocation"
> >   	default BLOBLIST_SIZE if BLOBLIST_FIXED || BLOBLIST_ALLOC
> > -	default 0x0 if BLOBLIST_PASSAGE
> >   	default 0x20000 if (ARM && EFI_LOADER && GENERATE_ACPI_TABLE)
> >   	help
> >   	  Sets the size of the bloblist in bytes after relocation. Since U-Boot
> > 
> > Because in this case we do need to set the size of the bloblist we use
> > internally to non-zero?
> > 
> That makes sense. The relocation in board_f will fail, as reserve_bloblist
> relies on this value being non-zero. However, if CONFIG_BLOBLIST_PASSAGE
> implies GD_FLG_SKIP_RELOC, then the relocation may not be necessary?

We don't need to worry about the GD_FLG_SKIP_RELOC case really, it's a
corner case of the ARC architecture and nothing else. We do want to
however copy the bloblist from where it was passed to us (possibly in
the middle of memory for example) and move it to an area we can reserve.

-- 
Tom

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