[PATCH 1/2] board: ti: am62x: am62x.env: Fix boot_targets

[Simon Glass]

Hi Andrew,

On Mon, 6 Nov 2023 at 10:27, Andrew Davis <afd at ti.com> wrote:
>
> On 11/6/23 9:31 AM, Tom Rini wrote:
> > On Mon, Nov 06, 2023 at 11:23:51AM +0530, Manorit Chawdhry wrote:
> >> Hi Simon,
> >>
> >> On 11:22-20231005, Simon Glass wrote:
> >>> Hi Nishanth,
> >>>
> >>> On Thu, 5 Oct 2023 at 11:16, Nishanth Menon <nm at ti.com> wrote:
> >>>>
> >>>> On 12:10-20231005, Nishanth Menon wrote:
> >>>>> On 12:36-20231005, Tom Rini wrote:
> >>>>>> On Thu, Oct 05, 2023 at 09:19:48AM -0500, Andrew Davis wrote:
> >>>>>>> On 10/4/23 8:54 AM, Nishanth Menon wrote:
> >>>>>>>> On 08:48-20231004, Andrew Davis wrote:
> >>>>>>>>> On 10/4/23 8:23 AM, Roger Quadros wrote:
> >>>>>>>>>> ti_mmc is not a valid boot_target for standard boot flow so
> >>>>>>>>>
> >>>>>>>>> Is there some way to make it into a valid boot_target? Otherwise
> >>>>>>>>> how do we use uEnv.txt files, or boot from FIT images with overlays?
> >>>>>>>>
> >>>>>>>> envboot takes care of uEnv.txt file (see
> >>>>>>>> https://lore.kernel.org/all/20231004132324.44198-3-rogerq@kernel.org/)
> >>>>>>>>
> >>>>>>>> Early remote proc loading and FIT image is a question for stdboot itself.
> >>>>>>>>
> >>>>>>>
> >>>>>>> If stdboot is missing these features then we shouldn't switch until it
> >>>>>>> has them. I'm all for switching to this, but only if it is complete.
> >>>>>>
> >>>>>> Depends on what you mean?  Did you mean an option to run scripts
> >>>>>> (exists) or an option to do what TI needs done, via
> >>>>>> boot/bootmeth_something.c ?  If the latter, someone from TI needs to
> >>>>>> figure out what that should be and do (but plumbing-wise everything it
> >>>>>> needs should exist).
> >>>>>
> >>>>> Andrew is generalizing here (on the wrong patch though).
> >>>>>
> >>>>> On am62x platforms, there is nothing regressing with this series. The
> >>>>> challenge is early remote_proc loading which is done for J7* platforms.
> >>>>>
> >>>>> How that is initiated as part of bootmethods is something of a gap.
> >>>>>
> >>>>> The other gap has been support for uEnv.txt -> which we can workaround
> >>>>> at the moment by using CONFIG_BOOTCOMMAND="run envboot; bootflow scan
> >>>>> -lb" in defconfig (This series from Roger already does that - hence I am
> >>>>> saying that Andrew is complaining on the wrong series).
> >>>>>
> >>>>> Ideally, we should just have CONFIG_BOOTCOMMAND="bootflow scan -lb" and
> >>>>> uEnv.txt remoteproc loads and the various standard bootmethods should
> >>>>> "just work".
> >>>>
> >>>>
> >>>> I forgot to add: FIT image authenticated boot flow. That is really what
> >>>> ti_mmc distroboot method was trying to solve.
> >>>>
> >>>> Maybe Simon or someone know how the stdboot flow handles authenticated
> >>>> kernel image and dtb boot flow with FIT image?
> >>>
> >>> Yes you can use FIT configuration verification and things should work as normal.
> >>>
> >>
> >> Could you give any reference documentation for this?
> >
> > I suspect you should start with doc/usage/fit/beaglebone_vboot.rst
> >
>
>  From that doc:
>
> ```
> Boot the board using the commands below::
>
>      setenv bootargs console=ttyO0,115200n8 quiet root=/dev/mmcblk0p2 ro rootfstype=ext4 rootwait
>      ext2load mmc 0:2 82000000 /boot/image.fit
>      bootm 82000000
> ```
>
> This is very much not stdboot :( This doc has some good and current info on building
> a secure FIT image, but much of it is showing its age. Stdboot is still missing
>
>   * ability to limit boot mode search to only one image (FIT)

What does this mean? Can you please be more specific or give an example?

>   * fetching and applying FIT overlay/config strings

Re overlays, is this the 'extension' command? What are config strings?

>   * remote proc loading

What command can do this?

>   * uEnv.txt processing

What command can do this?

>
> Last two can be solved by adding to CONFIG_BOOTCOMMAND before calling `bootflow scan`
> as suggested above. Until we figure out the first two I don't see us ready to switch.

I'm happy to help figure this out.

Regards,
SImon