Hi,
I was pleasantly surprised to get so many comments on this topic.
Thank you everyone for your input!
Since I want to avoid duplicating the i2c bus driver in a PBL capable
version, I decided to have a common barebox device tree for all boards.
This means that the detection takes place in the board init code and
then prepends the compatible with the matching board-specific entry.
If at some point the hardware no longer allows this approach, I still
can switch to the i2c-early solution.
Thanks
~Matthias
Am 16.05.2022 um 10:07 schrieb Sascha Hauer:
On Fri, May 13, 2022 at 02:10:32PM +0200, Matthias Fend wrote:
Hi Sascha,
Am 13.05.2022 um 13:00 schrieb Sascha Hauer:
Hi Matthias,
On Fri, May 13, 2022 at 10:55:02AM +0200, Matthias Fend wrote:
Hi,
I'm looking for a solution to support multiple boards with just one barebox
image. The few core components that are relevant for barebox are the same on
all boards, so that the same barebox image runs on all boards. It is
possible to dynamically detect the board type inside barebox, but as this
requires some infrastructure it is not possible during lowlevel init. So
basically Barebox should boot with a minimal core device tree, detect the
board type and then use the corresponding device tree of the detected board.
Something similar to arch/arm/boards/stm32mp15xx-dkx/lowlevel.c but not at
low level.
Do you even need the full device tree in barebox? The minimal core
device tree might be enough for barebox and only the kernel is then
booted with the full device tree.
If there is no trick to changing the used device tree at boardlevel init,
then this might be a possibility.
Replacing the live tree after it has been partly probed already is
dangerous and barebox is not really prepared for that.
The core device tree might not be as minimal then and in exceptional cases
minor fixups in the board code will be needed, but I think it could work.
In such a case, how should one ensure that the appropriate blspec entry is
booted? Maybe by simply replacing/updating the compatible string in the live
device tree after the board was detected?
As it happens Oleksij has just introduced of_prepend_machine_compatible()
exactly for this usecase. You can find it in current next branch.
Sascha
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