RPX-CLLF & Flash root filesystem

RPX-CLLF & Flash root filesystem

[Sebastien Ruel]

Hi there,

I have an Embedded-Planet RPX-CLLF 860P board, and i'm trying to put a
root filesystem on the flash so I will no longer depend on nfs.

Up to date, i've been able to put the Linux image inside the Flash
memory, but I'm still using BOOTP and NFS for the root filesystem.

I'm using Hardhat Linux 2.2.14, with the standard PlanetCore Bootloader
v1.03.

Is there a procedure out there that could help me do this?

Thank's

Sebastien Ruel
system engineer
Oerlikon Contraves
Montreal, Canada.


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Re: RPX-CLLF & Flash root filesystem

[Sebastien Ruel]

Hello Scott,
initrd.txt is only part of the answer. I'm missing info on how to tell
Linux where to fetch the root filesystem.
Once a minimal/functional root filesystem has been created (and
compressed), you have to put it somewhere in the Flash memory (just like
the Linux image).
When the system boots, it needs to "see" this root filesystem that is
inside the flash.

I will continue to experiment different things.


Scott Anderson wrote:

>Sebastien Ruel wrote:
>
>>Is there a procedure out there that could help me do this?
>>
>
>Is the description in linux/Documentation/initrd.txt what you are
>looking for?
>
>    Scott Anderson
>    scott_anderson@mvista.com   MontaVista Software Inc.
>    (408)328-9214               1237 East Arques Ave.
>    http://www.mvista.com       Sunnyvale, CA  94085
>


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Re: RPX-CLLF & Flash root filesystem

[Wolfgang Denk]

In message <3BD5E62D.8000807@oerlikon.ca> you wrote:
>
> initrd.txt is only part of the answer. I'm missing info on how to tell
> Linux where to fetch the root filesystem.

This depends on how you load and boot Linux.

> Once a minimal/functional root filesystem has been created (and
> compressed), you have to put it somewhere in the Flash memory (just like
> the Linux image).

When using the "standard" bootloader method, you will run

	make zImage.initrd

which builds a  binary  image  that  contrains  the  bootloader,  the
compressed  Linux kernel image, and the (compressed) ramdisk image as
one file, "zImage.initrd".

With PPCBoot, you can build your kernel and ramdisk images separately
or optionally combine them as one file.

> When the system boots, it needs to "see" this root filesystem that is
> inside the flash.

The bootloader takes care of passing the  correct  arguments  to  the
Linux kernel.

With PPCBoot you pass the addresses of both images  as  arguments  to
the "bootm" command.

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
To the systems programmer,  users  and  applications  serve  only  to
provide a test load.

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Re: RPX-CLLF & Flash root filesystem

[Jim Thompson]

> With PPCBoot you pass the addresses of both images  as  arguments  to
> the "bootm" command.

Wolfgang,

Have you considered cramfs support for ppcboot?

Jim

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Re: RPX-CLLF & Flash root filesystem

[Wolfgang Denk]

Hi Jim,

in message <15318.24383.143536.778353@zaphod.smallworks.com> you wrote:
>
> > With PPCBoot you pass the addresses of both images  as  arguments  to
> > the "bootm" command.
>
> Have you considered cramfs support for ppcboot?

Ummm... I think this is a misunderstanding on your side. Support  for
the  root  filesystem is an issue for the Linux kernel configuration,
PPCBoot is completely unaffected by this.

The great flexibility is IMHO one of the strongest points of PPCBoot.
Assuming that you have support  for  all  filesystems  and  partition
types  configured  for  Linux,  you  can  use  the  SAME Linux kernel
image...

...and load it from flash:

	=> setenv kernel_addr 0x40040000

...and load it using DHCP or BOOTP or plain TFTP:

	=> setenv kernel_addr 0x00100000
	=> tftp $(kernel_addr) /tftpboot/pImage

...and load it from IDE device 0, partition 3 (hard disk, CompactFlash, etc):

	=> setenv kernel_addr 0x00100000
	=> disk $(kernel_addr) 0:3

etc. (depending on the board, add Floppy Disk, CDROM, SCSI, ...)


...and boot with a ramdisk image (compressed or uncompressed):

	=> setenv ramdisk_addr 0x40200000
	=> setenv bootargs root=/dev/ram rw ...
	=> bootm $(kernel_addr) $(ramdisk_addr)

...and boot it with root filesystem over NFS:

	=> setenv bootargs root=/dev/nfs rw nfsroot=...
	=> bootm $(kernel_addr)

...and boot it with root filesystem on IDE device 0, partition 5:

	=> setenv bootargs root=/dev/hda5 ...
	=> bootm $(kernel_addr)

...and boot it with root filesystem on MTD partition 3 with a
   JFFS/JFFS2 filesystem:

	=> setenv bootargs root=/dev/mtdblock2 ...
	=> bootm $(kernel_addr)

etc. etc. - all with the same kernel image, and  in  any  combination
you like.


PPCBoot does not need to know about the root  filesystem  type  -  it
just  has to know how to load the Linux kernel; for example, we don;t
have NFS support in PPCBoot but can boot a Linux kernel which  mounts
the root filesystem over NFS.

Does this explain your question, or am I missing something?

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
You can love it, change it, or leave it.    There is NO other option.
But do not complain - it is your own choice...                  -- wd

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