[U-Boot] [PATCH 3/7] cmd: bootimg: Add bootimg command

[Simon Glass]

Hi Sam,

On Tue, 24 Sep 2019 at 11:41, Sam Protsenko <semen.protsenko at linaro.org> wrote:
>
> Hi Igor,
>
> On Mon, Sep 23, 2019 at 11:36 PM Igor Opaniuk <igor.opaniuk at gmail.com> wrote:
> >
> > Hi Simon,
> >
> > On Fri, Sep 20, 2019 at 8:45 PM Simon Glass <sjg at chromium.org> wrote:
> > >
> > > Hi,
> > >
> > > On Thu, 19 Sep 2019 at 12:28, Sam Protsenko <semen.protsenko at linaro.org> wrote:
> > > >
> > > > This command can be used to extract fields and image payloads from
> > > > Android Boot Image. It can be used for example to implement boot flow
> > > > where dtb is taken from boot.img (as v2 incorporated dtb inside of
> > > > boot.img). Using this command, one can obtain needed dtb file from
> > > > boot.img in scripting manner, and then apply needed dtbo's (from "dtbo"
> > > > partition) on top of that, providing then the resulting image to bootm
> > > > command in order to boot the Android.
> > > >
> > > > Also right now this command has the sub-command to get an address and
> > > > size of recovery dtbo from recovery image. It can be further parsed using
> > > > 'dtimg' command and merged into dtb file (for non-A/B devices only, see
> > > > [1,2] for details).
> > > >
> > > > [1] https://source.android.com/devices/bootloader/boot-image-header
> > > > [2] https://source.android.com/devices/architecture/dto/partitions
> > > >
> > > > Signed-off-by: Sam Protsenko <semen.protsenko at linaro.org>
> > > > ---
> > > >  cmd/Kconfig   |   8 +++
> > > >  cmd/Makefile  |   1 +
> > > >  cmd/bootimg.c | 177 ++++++++++++++++++++++++++++++++++++++++++++++++++
> > > >  3 files changed, 186 insertions(+)
> > > >  create mode 100644 cmd/bootimg.c
> > >
> > >
> > > Shouldn't this be a subcommand of avb?
> >
> > I think there is some misunderstanding here, as avb
> > is used only for signature verification/roll-back protection, other
> > aspects of booting Android (parsing android boot image) are
> > handled by other commands (for instance, bootm).
> >
> > Howewer, I think (IMHO) that `bootimg` isn't a good choice for the
> > command name , which major functionality is manipulating
> > dtb/dtbos.
> >
>
> Actually, 'bootimg' manipulates only Android boot image, but new
> Android Boot Image v2 happen to have DTB field. For DTBO files in
> Android we already have 'dtimg' command.
>
> Simon,
>
> This command is not connected with AVB. It's only needed to obtain
> Android Boot Image payloads. We can't integrate its functionality in
> 'bootm' command, because we would need to merge some DTBO files (from
> 'dtbo' partition) into DTB file obtained from boot image. And bootm
> command can't possibly know which DTBO files vendor would like to use
> (e.g. different DTBOs for different boards). That's why I came up with
> 'bootimg' command.

OK, so can we say this is specific to Android. So perhaps 'boota' ?

Minor point - boom allows passing an image address rather than
requiring loadaddr to be set.

>
> Actually I think that we should think about implementing
> 'boot_android' next. Because the boot script is becoming quite
> cluttered. But we should have those tiny commands anyway, as it's
> convenient for development and provides a more flexible way to boot
> Android.

Agreed on both counts.

>
> I'm having presentation today at Linaro Connect, highlighting new
> Android boot scheme. Slides will be available at [1]. The Android boot
> flow becomes more and more extensive, so I think it's time to start
> discussion between community, Google and vendors w.r.t. this topic.
> One point we should bring up is the possibility to use FIT image
> instead of bunch of Android images. I hope this is discussable.

That sounds like a good idea.

>
> But for now I think we should stick to established Android boot
> architecture, as it was published at [2] and mandatory for new devices
> launching with Android 10.

OK. Let's make sure to add sandbox tests for new functionality too.


- SImon

>
> Thanks!
>
> [1] https://connect.linaro.org/resources/san19/san19-217/
> [2] https://source.android.com/devices/bootloader
>
> > >
> > > Regards,
> > > Simon
> >
> >
> >
> > --
> > Best regards - Freundliche Grüsse - Meilleures salutations
> >
> > Igor Opaniuk
> >
> > mailto: igor.opaniuk at gmail.com
> > skype: igor.opanyuk
> > +380 (93) 836 40 67
> > http://ua.linkedin.com/in/iopaniuk