[WIC] Multiple WKS Files

[WIC] Multiple WKS Files

[Rudolf J Streif]

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eMMC devices commonly have three hardware partitions: two boot
partitions and a user partition. I was looking for a convenient way to
have wic build an image for the boot partition and one for the user
partition. However, that does not seem to be possible right out of the
box. The variable WKS_FILE only accepts one file and not a list. The
class image_types_wic.bbclass uses WKS_FILES internally but that seems
to be a search list and the code only builds the file it finds first.

Is my understanding correct?

Any smart ideas to make this work?

Thanks,
Rudi





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Re: [yocto] [WIC] Multiple WKS Files

[Joshua Watt]

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On Sat, May 2, 2020, 1:22 PM Rudolf J Streif <rudolf.streif@ibeeto.com>
wrote:

> eMMC devices commonly have three hardware partitions: two boot
> partitions and a user partition. I was looking for a convenient way to
> have wic build an image for the boot partition and one for the user
> partition. However, that does not seem to be possible right out of the
> box. The variable WKS_FILE only accepts one file and not a list. The
> class image_types_wic.bbclass uses WKS_FILES internally but that seems
> to be a search list and the code only builds the file it finds first.


I think part of the problem is that wks files are tied to a rootfs image,
so it's not currently possible to have multiple because there is no way to
differentiate them. Also because of that it's a little odd to have a wks
file that doesn't reference the rootfs it's built with.

You might be able to do it by making a simple dummy image recipe for the
boot partition(s), then overriding the WKS_FILE variable for the image with
a pn override in the machine.conf file (e.g. WKS_FILE_pn-my-emmc-boot =
"emmc-boot.wks" )


> Is my understanding correct?
>
> Any smart ideas to make this work?
>
> Thanks,
> Rudi
>
>
>
>
> 
>

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Re: [yocto] [WIC] Multiple WKS Files

[Rudolf J Streif]

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On 5/2/20 2:47 PM, Joshua Watt wrote:
>
>
> On Sat, May 2, 2020, 1:22 PM Rudolf J Streif <rudolf.streif@ibeeto.com
> <mailto:rudolf.streif@ibeeto.com>> wrote:
>
>     eMMC devices commonly have three hardware partitions: two boot
>     partitions and a user partition. I was looking for a convenient way to
>     have wic build an image for the boot partition and one for the user
>     partition. However, that does not seem to be possible right out of the
>     box. The variable WKS_FILE only accepts one file and not a list. The
>     class image_types_wic.bbclass uses WKS_FILES internally but that seems
>     to be a search list and the code only builds the file it finds first.
>
>
> I think part of the problem is that wks files are tied to a rootfs
> image, so it's not currently possible to have multiple because there
> is no way to differentiate them. Also because of that it's a little
> odd to have a wks file that doesn't reference the rootfs it's built with.
>
> You might be able to do it by making a simple dummy image recipe for
> the boot partition(s), then overriding the WKS_FILE variable for the
> image with a pn override in the machine.conf file (e.g.
> WKS_FILE_pn-my-emmc-boot = "emmc-boot.wks" )

Thank you, Joshua. I might try your idea. I have noticed that it is tied
to the rootfs as I tried to use ondisk/ondrive to create images for
different partitions. But that did not work. Actually, the use of the
ondisk/ondrive parameter is not entirely obvious to me (but I also have
not dissected the code to figure it out).

It might be worthwhile looking into enhancing wic to be able to create
multiple images. Devices now also use universal flash storage (UFS)
which supports multiple logical disks like a SCSI drive once it is
provisioned.

>
>
>     Is my understanding correct?
>
>     Any smart ideas to make this work?
>
>     Thanks,
>     Rudi
>
>
>
>
>
>
> 

-- 
-----
Rudolf J Streif
CEO/CTO ibeeto
+1.855.442.3386 x700


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Re: [yocto] [WIC] Multiple WKS Files

[Joshua Watt]

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On 5/4/20 11:14 AM, Rudolf J Streif wrote:
>
>
> On 5/2/20 2:47 PM, Joshua Watt wrote:
>>
>>
>> On Sat, May 2, 2020, 1:22 PM Rudolf J Streif 
>> <rudolf.streif@ibeeto.com <mailto:rudolf.streif@ibeeto.com>> wrote:
>>
>>     eMMC devices commonly have three hardware partitions: two boot
>>     partitions and a user partition. I was looking for a convenient
>>     way to
>>     have wic build an image for the boot partition and one for the user
>>     partition. However, that does not seem to be possible right out
>>     of the
>>     box. The variable WKS_FILE only accepts one file and not a list. The
>>     class image_types_wic.bbclass uses WKS_FILES internally but that
>>     seems
>>     to be a search list and the code only builds the file it finds first.
>>
>>
>> I think part of the problem is that wks files are tied to a rootfs 
>> image, so it's not currently possible to have multiple because there 
>> is no way to differentiate them. Also because of that it's a little 
>> odd to have a wks file that doesn't reference the rootfs it's built with.
>>
>> You might be able to do it by making a simple dummy image recipe for 
>> the boot partition(s), then overriding the WKS_FILE variable for the 
>> image with a pn override in the machine.conf file (e.g. 
>> WKS_FILE_pn-my-emmc-boot = "emmc-boot.wks" )
>
> Thank you, Joshua. I might try your idea. I have noticed that it is 
> tied to the rootfs as I tried to use ondisk/ondrive to create images 
> for different partitions. But that did not work. Actually, the use of 
> the ondisk/ondrive parameter is not entirely obvious to me (but I also 
> have not dissected the code to figure it out).
>
I haven't used it a whole lot because of the way we provision our 
devices, but I think its mostly so that wic can create a valid fstab in 
the root file system that will mount all the partitions. This way, the 
root file system image can remain generic and work with different 
partitions layouts specified in the wks file.

> It might be worthwhile looking into enhancing wic to be able to create 
> multiple images. Devices now also use universal flash storage (UFS) 
> which supports multiple logical disks like a SCSI drive once it is 
> provisioned.
>
Yes, that would be really nice. I don't think that wic currently has any 
concept of "hardware partitions" (e.g. the emmc boot partitions or the 
UFS SCSI LUNs), just GPT/MBR partitions. I'm not sure how you would add 
support for it.


>>
>>
>>     Is my understanding correct?
>>
>>     Any smart ideas to make this work?
>>
>>     Thanks,
>>     Rudi
>>
>>
>>
>>
>>
>>
> -- 
> -----
> Rudolf J Streif
> CEO/CTO ibeeto
> +1.855.442.3386 x700
>
> 

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