Howto implement bootchooser <-> rauc interaction

[Konstantin Kletschke]

Hi :-)

On Fri, Dec 17, 2021 at 10:46:42AM +0100, Ahmad Fatoum wrote:
 
> It was backported to stable in v5.10.20. Backport commit is 663a18271.

Sorry my git/google-foo is unsufficient, how do I get my hands on this
commit?

> > So one has to take care of the parent note size being big enough to contain the sum of
> > all length and thse itself must not overlap, right?
> 
> Yes. Device Tree compiler helps here a bit by warning if two nodes on the same bus
> have the same base address.

Okay.

> Open Firmware. It's the original standard that described device trees.

Oh, I wasn't aware, thanks for the information.

> > On the other hand, I could access plenty of space unallocated after the MBR if 1st partition
> > starts at a late sector like 1024 or so.
> 
> Latter is what I usually do.

Okay.

> arch/arm/dts/imx6qdl-prti6q-emmc.dtsi places it on eMMC. Check it out.

Yes, I will do, thank you!

> > And is doing this state thing in a file (for example on the 1st  FAT where barebox.env is)
> > for barebox and raux/barebox-state possible or not?
> 
> FAT isn't power-fail safe. It's ok for reading or writing stuff during
> development (e.g. environment), but you really don't want to use it
> for barebox-state that's meant to be power-fail safe.

Okay again, I am convinced about the no-file-in-FAT state.

So, just to be shure for the state OF partition placed after the MBR before 1st
MBR partition:

If I have 1st partition's start sector being 2048 I hafe plenty of room
before this after the MBR.

The barebox state OF partition should be in there and I could place it
at

reg = <0x300 0xfffff>

because the MBR ends at 0x1ff and the 1st partition starts at
sector 2048 ( 2048*512byte=1MB=0x10000), is that correct, is the reg
addressing done this way?

Of course a length of 0xfffff is far too much,
just to get a picture. Also to transfer this to an OF partition in a MBR
partition.

The container partition reg = <0xc0000 0x40000> in imx6qdl-prti6q-emmc.dtsi seems
to be directly going to below a MBR partiton starting at 2048th sector
with size 256kB, correct?  

Thanks for your patience!

Regards
Konstantin

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