On Thu, Apr 9, 2015 at 11:07 PM, Stefan Roese sr@denx.de wrote:
Hi Tim,
(added Igor to cc)
On 10.04.2015 00:58, Tim Harvey wrote:
It seems the U-Boot's env storage is implemented by various types of storage from common/env_*.c, one (and only one) which is included by common/Makefile based off of the CONFIG_ENV_IS_IN_* config.
I want to build a single uboot image which can be installed on one of several supported boot devices (NAND, SATA, SD for example) and have the env storage hooked to the device that was detected as the boot device. Am I correct in assuming this is not currently possible and that instead I would have to build 3 versions of uboot each with one type of storage defined?
If it turns out that this is not currently possible, I'm open to suggestions on how to rectify it (or if you think I'm crazy for wanting to have a single uboot image for the above please explain your reasoning). I'm thinking I would start by making the env_init/saveenv functions (I believe those are the only ones that need to be implemented by an env storage subsystem) unique function names, then creating a wrapper for those functions that call the right one.
IIRC, Compulab has such a feature implemented in some of their U-Boot versions. Igor, please either correct me if I'm wrong. Or elaborate how you have implemented this dynamic env feature.
Thanks, Stefan
Igor,
I think what Stefan might be thinking of is ENV_IS_EMBEDED used in cm-bf537. It looks like this support was originally for the renesas sh775* boards which don't look to be maintained any longer. I haven't gone through it in depth yet but it seems this has to do with embedding the env within U-Boot binary itself yet I'm clear why this isn't just using the default_environment array (maybe it predated that notion?). If I'm understanding it correctly ENV_IS_EMBEDDED is not really what I'm looking for and likely that support could use some cleanup and updating.
I have an RFC patch I'm working on that will allow CONFIG_ENV_IS_DYNAMIC that currently does the following: - makes env_init(), saveenv(), env_relocate_spec(), env_ptr, env_name_spec namespace unique in env_*.c - provide a env_init(), saveenv(), env_relocate_spec() in env_common.c using spl_boot_device() to determine the boot device and calling the namespace unique impl instead - currently supports only mmc/nand
I don't see any clear maintainers of anything env related so I'm not sure who else may want to be involved in this conversation.
(added Wolfgang to cc)
Tim