Re: booting from cramfs in flash

Steven Hein wrote:

My cramfs adventure continues.....

Okay, so I have a cramfs filesystem image creaed created.
Now, how do I tell the kernel to boot using that filesystem
when the filesystem is an image in flash?

Maybe I'm on the wrong path, but my previous setup used a compressed
kernel and gzip'ed ext2 filesystem as an initial ramdisk, which
also served as my permanent filesystem.   So I thought I should
be able to just replace my old initrd with my new cramfs image,
tell the kernel where it is (in flash), and it would go.

It turns out that cramfs is not supported for a root fs or initrd.
Basically, the kernel checks a hardcoded list of supported filesystems
and if the MAGIC number doesn't match it bails.  Midori has a patch to
add cramfs to this list.  I believe it is in thier kernel package.

But, that's not the case for me so far. If I pass the address in
flash of my cramfs image as the initrd_start
and initrd_end (in R3/R4, the kernel craps out because it can't reuse
the pages where I told it that the initrd lives).

So,how do I make this connection?  Or, do I still need an ext2
initrd like I used before?  If so, then how do I mount the CRAMFS
filesystem that is an image sitting flash?

You can do that too.  Actually that is how we do it on the iPaq.  You
need to enable MTD, so your flash looks like a block device. then
'mount' can mount cramfs images.

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