Re: [Ltib] Questions regarding Usage Scenarios

[Robert S. Grimes]

Hi Stuart,

Stuart Hughes wrote:
> Hi Bob,
>
> 1-2/ Definitely use Savannah as your baseline.  Although at times this
> lags in some respects, often the BSP ISO release images are older than
> the Savannah CVS.  The real deciding factor though is that if you use
> Savannah for a custom BSP you will be able to get some support.
> Furthermore, if you have a local tree (as you mention in 2) you will
> have a way of synchronising when there are updates at Savannah (whether
> CVS or later git).  If you use an ISO snapshot, there's no way to know
> if/when this might be updated.
>   
This is just the answer I needed - thanks!

> 3/ An ISO image generated from LTIB contains all the source/patches
> referenced in the default configuration.  Optionally, there's a
> "--fullbsp" flag that can be given that will pull in all the sources for
> all the packages (this is of course has a much larger footprint).
>
> Fundamentally to have your "own BSP" in LTIB means having/maintaining:
>
> a) A toolchain.  Often there is already one available that you can use.
>
> b) A Linux kernel source tree and config file (maybe just some patches
> against a standard kernel.org, or even just a vanilla kernel)
>
> c) Maintaining a directory e.g.: config/platform/mcf5329micro/
> This may contain as few files as:
>    * defconfig          : the default LTIB configuration
>    * main.lkc           : your config settings to select the kernel
>    * kernel-xxx.spec.in : listing the source+patches for the kernel
>    * linux-xxx.config   : your kernel config (not always needed)
>
>   
Excellent information!  I'm not sure I understood all this - most, yes, 
but probably not all! - so this is just what I need.

> My advice would be that if it's at all possible to have your platform
> represented in Savannah CVS with the kernel source/patches uploaded to
> the GPP.  This would mean the burden of support/releases would be much
> less for you.  Some other users have already submitted their own BSP
> abstractions and have them in Savannah (cobra5475, mpc82xx, phy3250).
>   
Hmm.  Well, the decision is probably my client's to make.  Personally, I 
assumed it not interesting to GPP users, as the board will not be 
available to them, so it would just be clutter.  Does it still make 
sense to do so?

> WARNING: for MMUless platforms only a sub-set of packages are available.
> This is because there is no 'fork' in MMUless (there is vfork) and so
> packages need adaptation or may fundamentally not be easy to port to a
> MMUless environment.  Therefore if something is in LTIB and not uClinux,
> this may well be because this works only for platforms with MMU (there's
> guards in the package selection see "depends CAP_HAS_MMU" in
> config/userspace/packages.lkc).  So for MMU-full platforms, LTIB would
> probably be the best choice, but for MMUless platforms uClinux-dist may
> be a better choice.  The deciding factor would be if you want to use
> LTIB because of it's structure (rpm packages, release ISOs etc) rather
> than the package content.
>   
Yes, of course - this much I understood...

Thanks!
-Bob