Hi Sergey, Hi Heiko,
On 26.04.2016 07:43, Heiko Schocher wrote:
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.
I've missed such a tool a few years ago while porting U-Boot & Linux
to a i.MX6 based NAND booting board as well. And noticed since then
that barebox has included such a tool:
http://lists.infradead.org/pipermail/barebox/2014-March/018202.html
Perhaps its not too much work to port this tool over to U-Boot?
Just an idea...
Thanks,
Stefan
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