Re: Re: RomFS

Hi

Hi!

That sounds good and it works. snip

But how can I mount this rom/ramdisk from the kernel as its root disk?

Well, um, you can't.
I guess you have to write a simple read-only block device driver yourself...
I think i've seen a posting before by a guy alex@signum.se who has written
a flash file system, you might be able to steal some code from him.
Search the linuxppc-dev and linuxppc-embedded lists.

What do I have to supply as boot parameter?

I would like to store the entire application in the flash (kernel + application)

If you have enough ram, make an initrd and load with 8xxrom (I don't remember
the command, but i've done it.)

But be sure to check/fix the ramdisk, it might be broken.

I don't know your budget, but small ATA-Flash cards are cheap.
And really nice.

I've got a almost-working pcmcia driver waiting to be bugchecked
and released here...

And 8xxrom boots from ATA-Flash too.

Cheers /

Magnus

\Ruedi

damm@kieraypc01.p.y.ki.era.ericsson.se on 31.01.2000 16:23:22
An: Ruedi.Hofer@ascom.ch @ MailGate
Kopie:
Thema: Re: RomFS

quoted

Hi,

Hi!

quoted

My ADS board is happily running with a NFS mounted linux box.

Great!

quoted

Now I have to put all the code into the flash memory to get a standalone
solution.

I'm using the 8xxrom Bootloader. In a file called config.h I can configure
CONFIG_DISK_ROM.  As far as I can see, the bootloader assumes
then that a complete FAT filesystem is stored from the position
0xFE020000 in flash.

My question:
- Is my assumption right?

Well, there is a file in the disk directory called rom.c.
It is a simple read-only block driver for 8xxrom.
It does not know anything about filesystems, so you can use any filesystem you want
as long it is supported by 8xxrom.

In rom.h can you find a define called ROM_DISKSTART which is the start address
of the filesystem.

quoted

- How can I produce a FAT filesystem in a file, which I can download
  with MPC8BUG into the onboard flash?

You have to look somewhere on the net.
I usually create a ramdisk and make a filesystem and copy my things to it.
Then I umount it and use dd to copy the data to a file which I burn to
a flash.

quoted

- Does it have anything in common with the romfs driver which is supported
  by the kernel? (I think not)

Nope.
But it would sure be great if we could read one romfs image from the 8xxrom.

Good luck /

magnus