Hi,
On 20 February 2017 at 02:18, Dr. Philipp Tomsich philipp.tomsich@theobroma-systems.com wrote:
On 20 Feb 2017, at 08:22, Igor Grinberg grinberg@compulab.co.il wrote:
That sounds too odd... DT's purpose is to describe the h/w... and that does not look so... We also, have a dt file name in the environment, so this creates will create a chicken and an egg problem…
I don’t really follow… as far as I knew the DT name would have to come from some other source anyway, as the device containing the env might only be described through the device tree (e.g. mmc0).
Why? U-Boot can live pretty well w/o DT.
If U-Boot runs without DT, then nothing will/should change about how the setting is retrieved from CONFIG_ENV_OFFSET.
The platform that motivated this change is ARCH_SUNXI, which does not use per-board defines but aims to have one generic bootloader per-SoC.
I really don't think we should go that direction. DT is not meant to provide a solution to all your problems...
I don’t see how this is different from other entries in chosen and config as of today: common/autoboot.c allows an override through /config/bootdelay common/board_r.c uses /config/load-environment common/cli.c can pull in /config/bootcmd drivers/serial/serial-uclass.c uses /chosen/stdout-path
In fact, it is the absence of this mechanism that is causing problems today: CONFIG_ENV_OFFSET is not configurable through Kconfig, so we would need board-specific defines (e.g. CONFIG_SUNXI_BOARD_LYNX) and matching #ifdef primitives in a shared header (sunxi-common.h in our case).
Right. Exactly, I think we should move the CONFIG_ENV_OFFSET to Kconfig. And that will solve the problem.
Doing this would still get into the way of architectures that want to build a single ‘universal’ bootloader for their SoC: the ENV_OFFSET may not be the same across all board and vendor configurations. This can easily be handled with the (optional) prop in the DT, but not with the compile-time ENV_OFFSET.
If we decide to this, I’d at least like to introduce the function call to (the weak function) mmc_get_env_addr(…), so we can override this in the board code.
So putting this in the DT is the best (and least intrusive) option available.
Ok. I see your point now. Yet I think we should keep the DT to its purpose - which is to describe the h/w (and not the s/w placement layout).
Well actually we put things like flash map in there and the environment position seems like a very good thing to have there. So I like this patch. There is too compile-time configuration in U-Boot still...
In fact I wish we could support this for all environment types. Overall the environment drivers need some work to make them more similar...
Regards, Simon