[RFC] Qi Bootmenu

[Paul Fertser]

On Sat, Oct 10, 2009 at 01:24:56PM +1100, Carsten Haitzler wrote:
> On Fri, 09 Oct 2009 21:50:42 +0400 Paul Fertser <fercerpav at gmail.com> said:
> > Carsten Haitzler (The Rasterman) <raster at rasterman.com> writes:
> > >> This would require that the kernel partition in NAND is formated as a 
> > >> filesystem but then Qi couldn't read from it. Or am missing something
> > >> obvious here?
> > >
> > > the fs can be mounted as an offset from the start of a partition. you cn
> > > even split it into 2 partitions. 1 for kernel, 1 for rootfs. as such qi
> > > SHOULD be able to technically - it can read krenels from a FILESYSTEM on
> > > sd. it can read fs's.  no reason it cant read an fs from nand too (in
> > > principle) other than simply that having not been written in or explicitly
> > > avoided (can't think of a good reason myself if u handle fs's already).
> > 
> > And indeed Qi does read FSes from NAND. It uses ext2 factory partition
> > to extract usb MAC.
> 
> then no reason cramfs can't be added... or is it already there? imho it should
> be. that'd make the "kernel partition" much cleaner as it is a realfs - not
> just a kernel splatted onto the raw nand. oit allows for nice paritioning of
> that space for use of multiple bits of data - ie kenrel plus this
> rescuefs etc.

Currently Qi supports only ext2 and raw NAND. And it's ~easy. Anything
else would probably require building another abstraction layer. And
more complex code. Why not simply statically link initramfs in kernel
image? There's 8M in kernel partition, enough to fit the proposed
image. The only change that would be needed is to change the meaning
of the power button (since using AUX is risky on our SoC): currently
holding it gives you loglevel=8, we can make it mean boot from
NAND. For other devices where all the kernels will be located on uSD
we can make it mean boot from the 2nd partition or something like
that.

-- 
Be free, use free (http://www.gnu.org/philosophy/free-sw.html) software!
mailto:fercerpav at gmail.com