Re: [Ltib] How to get device nodes into zImage?

[Stuart Hughes]

Hi Ned,

Your kernel should be able to cope with ramdisk or cramfs (if you enable
via the config).  However I may have misunderstood (your layout issues).

Do you have to move away from NFS deployment now?  if you can wait I'll
try to figure out when I can put out the initramfs changes.  However
even if I do I fear they won't be what you need as we still keep the
kernel image and initramfs image separate (with the exception of some
Coldfire platforms I think).  Reading between the lines it sounds like
you want some scheme that has a single image with the initramfs combined
with the kernel?

I'm not sure how to move forward.

Regards, Stuart

On Tue, 2008-11-18 at 06:35 -0800, Ned Konz wrote:
> On Nov 18, 2008, at 3:32 AM, Stuart Hughes wrote:
> 
> > Hi Ned,
> >
> > I'm a bit confused here. zImage is normally just the kernel, the  
> > device
> > nodes come from whatever userspace package is selected.  The default  
> > for
> > imx27 is static.  You should see these in rootfs/dev/
> >
> 
> Yes. Things work fine when I have rootfs mounted via NFS.
> 
> The problem is that I don't have a bootloader that can deal directly  
> with any of the ramdisk formats I've been able to generate so far, and  
> the root file system has to have at least the device nodes for my  
> console and for whatever I'm going to get the remaining file systems  
> from.
> 
> I have 64 Mib of RAM, 2Mib of NOR flash (where the bootloader lives)  
> and 64Mib of NAND flash, currently separated into 4 chunks:
> 128K
> 4096K
> 22528K
> 38784K
> 
> These sizes come from a static table in the kernel; I haven't  
> experimented with changing the partitioning from the kernel command  
> line yet.
> 
> The yaffs filesystem that I can get the bootloader to create isn't  
> recognized by the kernel yaffs code, for some reason (or vice versa).
> 
> So far I haven't been able to get the system to boot and get through  
> mounting the new root, since the console goes away when I can't  
> successfully mount the root.
> 
> > When ramdisk or jffs2 image is made, the device nodes are not copied
> > from there, instead genext2fs takes the option -D (which is
> > bin/device_table.txt) which is what it uses to create the device nodes
> > within the image.
> >
> > As I said before, initramfs is coming to Savannah later.  However even
> > then we normally keep the kernel image and the userspace initramfs
> > separate (as for ramdisk or jffs2 image).  It is possible to combine
> > then (catted kernel+root) but generally we don't do this (some  
> > platforms
> > do IIRC).
> >
> 
> That would be fine in this case. I just need to get to the point where  
> I can run Linux; I can mount the NAND partitions using the Linux yaffs  
> code but so far haven't been able to put a root disk on them reliably.  
> The more I fool with the NAND the more bad blocks I seem to get, for  
> some reason.
> 
> I'm OK with running from an initramfs that's copied from NAND, because  
> I just need this thing to be going by several days ago.
> 
> Having to put in multiple 12+ hour days hasn't helped my clarity, and  
> I still need to finish the application part.
> 
> > Regards, Stuart
> >
> > On Tue, 2008-11-18 at 00:50 -0800, Ned Konz wrote:
> >> I've been banging my head against this:
> >>
> >> LTIB will make a zImage that contains most of the filesystem entries
> >> you need to run your system.
> >>
> >> Unfortunately, it lacks any device nodes (there are only a few empty
> >> directories under /dev).
> >>
> >> Later, a rootfs.ext2.gz may be produced that has all the proper  
> >> device
> >> entries in it.
> >>
> >> How can we get the device entries in the zImage? I've tried pointing
> >> the source for the INITRAMFS at the rootfs.tmp but it doesn't have  
> >> the
> >> device entries yet.
> >>
> >> What is the best way to get a fully - populated ramdisk image into  
> >> the
> >> zImage -- with the device entries?
> >>
> >> This is a lot easier than using a separate kernel image and rootfs
> >> image.
> >>
> >
> >
>