[PATCH 1/4] riscv: spl: Introduce SPL_OPENSBI_OS_BOOT

[Rick Chen]

Hi Tom

> On Fri, Dec 09, 2022 at 08:48:37AM -0500, Sean Anderson wrote:
> > On 12/7/22 01:23, Rick Chen wrote:
> > > In RISC-V, it only provide normal mode booting currently.
> > > To speed up the booting process, here provide SPL_OPENSBI_OS_BOOT
> > > to achieve this feature which will be call Fast-Boot mode. By
> >
> > Can you name this something different. We already have something called
> > fastboot in-tree (the Android-derived protocol) and there's a Microsoft
> > technology called fastboot (some kind of hibernation). "OS Boot" isn't
> > very specific either, since we (almost always) boot an OS. Maybe "Eagle
> > mode" by analogy to Falcon mode, which lets SPL directly boot an OS.
> >
> > (Is this substantially different from falcon mode anyway?)
>
> I was kind of wondering if this is different, really, from Falcon Mode.
> Falcon Mode didn't initially have to factor in other-firmware as that's
> not a hard requirement on arm32 like it is on arm64 or risc-v.  But my
> first read of this was that it seems like the RISC-V specific side of
> doing Falcon Mode and dealing with the prior stage needs correctly.
>

Yes. It is a little bit different from the Falcon mode (SPL_OS_BOOT=y).
When I try to enable SPL_OS_BOOT, it will encounter that SYS_SPL_ARGS_ADDR and
 jump_to_image_linux() shall be defined but they are un-necessary for RISC-V.
Because the flow of OpenSBI and SPL_OS_BOOT are totally different code
flow in board_init_r() of common/spl/spl.c.
That is why I added a new symbol called SPL_OPENSBI_OS_BOOT for this
RISC-V fast boot implementation.

Thanks,
Rick



> --
> Tom