Hello Sergey,
add Stefano to Cc as he is the imx6 custodian,
Am 25.04.2016 um 22:29 schrieb Sergey Kubushyn:
Hi everybody,
It looks like using kobs-ng utility is the only way to make a bootable NAND for i.MX6 and their siblings. There might be other utilities I'm not aware of but that doesn't change anything -- you need Linux (or whatever that utility runs on) running on your board to create and write all those FCB and other parts onto a virgin raw NAND device.
Yes, I stumbled over that too recently ...
This makes initial programming a cumbersome and complicated operation. One can not program NAND on a development machine as it is easy to do with e.g. SD Card -- the OS must run on the same board where that NAND is because NAND is not removable.
It is possible, of course, to assemble something on an SD Card and use that to program NAND but that assumes there is an SD Card slot on a target system and some means to tell it to boot off of SD Card. However it is not always a case -- there might be boards with NAND as only storage device available. That leaves only Serial/USB boot as only options for initial boot on a virgin board. However it does not provide means for writing the NAND U-Boot into actual NAND.
There are many different varieties of NAND chips so those FCB and other structures are not generic i.e. they can not be defined beforehead and just prepended to the actual U-Boot image. Even if we have made those a configuration parameters there are still bad block tables that are chip specific so they should be discovered first i.e. FCB should be built dynamically based on NAND scanning results.
Sure, one can write a custom first stage SPL that would've booted the actual U-Boot via the same Serial/USB interface and run it but then what? Let's assume the target board doesn't have ethernet so it would make it impossible to mount rootfs over NFS and no other storage devices available. It is still possible to load Linux kernel and bare minimal rootfs in initramfs image but that's a lot of serial downloading just for initializing NAND...
It would be nice to have a U-Boot command that would've allowed initial NAND setup and writing NAND U-Boot image to it properly updating the headers.
Yes, that would be great!
There might be other ways to do this that I might've overlooked...
Does anybody knows a ready-made solution or works on something suitable for this purpose? I don't want to re-invent the wheel starting my own solution so it would've been good to hear from other guys who might've solved this dilemma.
Sorry, I do not know another way.
Any thoughts?
I think, an U-Boot command which writes the headers into the nand would be a good thing.
tools/imximage.c is may the wrong place, as the infos in FCB and DBBT are dependend on the boards nand.
bye, Heiko