Yocto with Initial RamFS

Yocto with Initial RamFS

[Brian Smucker]

Hello,

I have an initial ramfs image that I want to convert to Yocto. That is 
in addition to the main yocto-based custom distro.

The initial ram fs is a tiny image based on uclibc (poky-tiny) and 
having busybox and two other compiled apps.  The main file system is 
eglibc-based.

How is this sort of thing typically done in the Yocto world?  Since the 
toolchain is totally different for the initial ramfs, do I need to have 
another distro and totally different directory for creating the 
initialramfs, giving two different distros and yocto directories?  Or 
can I somehow do it under the umbrella of one Yocto distro?

I would like some feedback on how this should be done.

Thanks,

Brian

Re: Yocto with Initial RamFS

[Brian Smucker]

Hi,

Was wondering why this has not been answered.  Maybe it is too dumb of a 
question? If so, let me know or point me to some documentation.

Thanks.

Brian

On 5/23/2014 11:37 AM, Brian Smucker wrote:
> Hello,
>
> I have an initial ramfs image that I want to convert to Yocto. That is 
> in addition to the main yocto-based custom distro.
>
> The initial ram fs is a tiny image based on uclibc (poky-tiny) and 
> having busybox and two other compiled apps.  The main file system is 
> eglibc-based.
>
> How is this sort of thing typically done in the Yocto world? Since the 
> toolchain is totally different for the initial ramfs, do I need to 
> have another distro and totally different directory for creating the 
> initialramfs, giving two different distros and yocto directories?  Or 
> can I somehow do it under the umbrella of one Yocto distro?
>
> I would like some feedback on how this should be done.
>
> Thanks,
>
> Brian

Re: Yocto with Initial RamFS

[Søren Holm]

Torsdag den 29. maj 2014 08:07:11 skrev Brian Smucker:
> Hi,
> 
> Was wondering why this has not been answered.  Maybe it is too dumb of a
> question? If so, let me know or point me to some documentation.
> 

I'm declaring an initramfs-image like this. As you can see the recipe is 
derived from core-image-minimal-initramfs. The package initramfs-vm provides 
the script /init executed on boot.

The "assembling" of the actual bootable image with initramfs and rootfs (in my 
case a squashfs) is done in another script.

<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
# initramfs for vm-image. Derived from core-image-minimal-initramfs
DESCRIPTION = "Small image capable of booting a a squashfs+aufs filesystem"

IMAGE_INSTALL = "initramfs-vm-boot busybox udev base-passwd"

# Do not pollute the initrd image with rootfs features
IMAGE_FEATURES = ""
IMAGE_LINGUAS = ""
#DISTRO_FEATURES = ""

inherit core-image

IMAGE_FSTYPES = "cpio"

IMAGE_PREPROCESS_COMMAND = "cb16_remote_bloat;"

cb16_remote_bloat() {
        rm -r ${IMAGE_ROOTFS}/boot
}
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

-- 
Søren Holm

Re: Yocto with Initial RamFS

[Brian Smucker]

Thanks Soren,

My followup question is: Can I mix toolchains in this situation?

Can I compile the initramfs binaries with the uclibc toolchain based on 
the poky-tiny distro and the regular file system binaries with the 
glibc-based toolchain (based on a different distro)?

If this is possible, how would I begin to do it?

Thanks,

Brian

On 5/29/2014 8:38 AM, Søren Holm wrote:
> Torsdag den 29. maj 2014 08:07:11 skrev Brian Smucker:
>> Hi,
>>
>> Was wondering why this has not been answered.  Maybe it is too dumb of a
>> question? If so, let me know or point me to some documentation.
>>
> I'm declaring an initramfs-image like this. As you can see the recipe is
> derived from core-image-minimal-initramfs. The package initramfs-vm provides
> the script /init executed on boot.
>
> The "assembling" of the actual bootable image with initramfs and rootfs (in my
> case a squashfs) is done in another script.
>
> <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
> # initramfs for vm-image. Derived from core-image-minimal-initramfs
> DESCRIPTION = "Small image capable of booting a a squashfs+aufs filesystem"
>
> IMAGE_INSTALL = "initramfs-vm-boot busybox udev base-passwd"
>
> # Do not pollute the initrd image with rootfs features
> IMAGE_FEATURES = ""
> IMAGE_LINGUAS = ""
> #DISTRO_FEATURES = ""
>
> inherit core-image
>
> IMAGE_FSTYPES = "cpio"
>
> IMAGE_PREPROCESS_COMMAND = "cb16_remote_bloat;"
>
> cb16_remote_bloat() {
>          rm -r ${IMAGE_ROOTFS}/boot
> }
> <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>

Re: Yocto with Initial RamFS

[Søren Holm]

Torsdag den 29. maj 2014 09:49:55 skrev Brian Smucker:
> Thanks Soren,
> 
> My followup question is: Can I mix toolchains in this situation?
> 
> Can I compile the initramfs binaries with the uclibc toolchain based on
> the poky-tiny distro and the regular file system binaries with the
> glibc-based toolchain (based on a different distro)?
> 
> If this is possible, how would I begin to do it?

I don't know, but I've got a simmilar need. Basically I was a very minimal 
busybox-static for the initramfs, but a "full-fledged" version for the main 
rootfs. I guess that's somehow the same thing.

Maybe you have an idea on how to do that?

 
-- 
Søren Holm

Re: Yocto with Initial RamFS

[Brian Smucker]

On 5/29/2014 12:38 PM, Søren Holm wrote:
> Torsdag den 29. maj 2014 09:49:55 skrev Brian Smucker:
>> Thanks Soren,
>>
>> My followup question is: Can I mix toolchains in this situation?
>>
>> Can I compile the initramfs binaries with the uclibc toolchain based on
>> the poky-tiny distro and the regular file system binaries with the
>> glibc-based toolchain (based on a different distro)?
>>
>> If this is possible, how would I begin to do it?
> I don't know, but I've got a simmilar need. Basically I was a very minimal
> busybox-static for the initramfs, but a "full-fledged" version for the main
> rootfs. I guess that's somehow the same thing.
>
> Maybe you have an idea on how to do that?
I don't know. I'm somewhat of a newbie here.

It seems this type of requirement should not be unusual in the embedded 
space.

Am hoping others can weigh in on this.

Thanks,

Brian

Re: Yocto with Initial RamFS

[Khem Raj]

On Thu, May 29, 2014 at 9:49 AM, Brian Smucker <bds@bsmucker.eu.org> wrote:
> My followup question is: Can I mix toolchains in this situation?
>

No, not easily. Although you can see if klibc is an option for you.
meta-initramfs has support for that

> Can I compile the initramfs binaries with the uclibc toolchain based on the
> poky-tiny distro and the regular file system binaries with the glibc-based
> toolchain (based on a different distro)?
>
> If this is possible, how would I begin to do it?
>
> T