Re: [Gumstix-users] Re: buildroot

[Dave S. <da...@sm...>]

Craig Hughes wrote:

> On Aug 30, 2005, at 12:21 PM, Dave Smith wrote:
>
>> I've just started doing something similar myself.  My idea was to  
>> modify the .mk files for non core stuff to use a new env var $ 
>> (TARGETUL_DIR) instead of $(TARGET_DIR).  This for XM owners would  
>> be a synomym for TARGET_DIR, but for others it would effectively  
>> point to a /usr/local directory on the MMC card mounted in a card  
>> reader (or something similar).
>
>
>> This would then give you a switch (i.e. where you pointed  
>> TARGETUL_DIR) to either everything in root_fs, or secondary  packages 
>> going uncompressed onto the MMC
>
>
> I don't like this approach as much as having 2 sets of targets, where  
> it defined TARGET_DIR differently for the two set of sub-makes.  The  
> way you propose means that if you change your mind and want to  
> install to flash instead of MMC or vice-versa, you have to edit lots  
> of make files, changing lots of lines in each file.  My way, you only  
> need to change the top-level Makefile to move the target(s) you  
> changed your mind about into the other variable.  Fundamentally, the  
> *.mk makefiles shouldn't really have to know what the ultimate  
> destination is.  They should just build themselves in whatever  
> upstream says their environment is, and then some later step does the  
> actual packaging (eg jffs2root.mk or mmcoverlay.mk which can be  
> written to look in the other target dir)
>
> C

If you wanted to move from Flash to MMC, you would only need to change 
the definition of the TARGETUL_DIR variable and all secondary targets 
would then get shifted to MMC.  There would be a one off hit in 
modifying some of the *.mk files, but that would be a simple search & 
replace for TARGET_DIR to TARGETUL_DIR for each target that was to be 
potentially MMCised.  They wouldn't know their final target, as that 
would be set by the top level makefile.  I don't see where you would 
define the second set of targets.  It's on a back burner right now 
anyway, so I'm happy to drop it if there is something better coming up :)

Regards,
Dave