[U-Boot] [PATCH V3 5/6] omap3_beagle: support findfdt and loadfdt for devicetree support

[Tom Rini]

On Mon, Jul 15, 2013 at 04:52:51PM +0200, Koen Kooi wrote:
> 
> Op 15 jul. 2013, om 16:49 heeft Tom Rini <trini at ti.com> het volgende geschreven:
> 
> > On Mon, Jul 15, 2013 at 02:16:50PM +0200, Koen Kooi wrote:
> >> 
> >> Op 15 jul. 2013, om 14:11 heeft Nishanth Menon <nm at ti.com> het volgende geschreven:
> >> 
> >>> For folks not using concatenated device tree with uImage, having
> >>> an handy function to find and load device tree is very handy.
> >>> 
> >>> So introduce findfdt and loadfdt and run findfdt by default to make
> >>> it easier on user scripts.
> >>> 
> >>> Signed-off-by: Nishanth Menon <nm at ti.com>
> >>> ---
> >>> V3: Fixes typo mistake reported in http://marc.info/?t=137358212300006&r=1&w=2
> >>> 
> >>> include/configs/omap3_beagle.h |   15 +++++++++++++++
> >>> 1 file changed, 15 insertions(+)
> >>> 
> >>> diff --git a/include/configs/omap3_beagle.h b/include/configs/omap3_beagle.h
> >>> index bdeee17..5ec8ade 100644
> >>> --- a/include/configs/omap3_beagle.h
> >>> +++ b/include/configs/omap3_beagle.h
> >>> @@ -210,6 +210,8 @@
> >>> #define CONFIG_EXTRA_ENV_SETTINGS \
> >>> 	"loadaddr=0x80200000\0" \
> >>> 	"rdaddr=0x81000000\0" \
> >>> +	"fdt_high=0xffffffff\0" \
> >>> +	"fdtaddr=0x80f80000\0" \
> >>> 	"usbtty=cdc_acm\0" \
> >>> 	"bootfile=uImage\0" \
> >>> 	"ramdisk=ramdisk.gz\0" \
> >>> @@ -250,6 +252,17 @@
> >>> 		"omapdss.def_disp=${defaultdisplay} " \
> >>> 		"root=${nandroot} " \
> >>> 		"rootfstype=${nandrootfstype}\0" \
> >>> +	"findfdt=" \
> >>> +		"if test $beaglerev = AxBx; then " \
> >>> +			"setenv fdtfile omap3-beagle.dtb; fi; " \
> >>> +		"if test $beaglerev = Cx; then " \
> >>> +			"setenv fdtfile omap3-beagle.dtb; fi; " \
> >>> +		"if test $beaglerev = xMAB; then " \
> >>> +			"setenv fdtfile omap3-beagle-xm.dtb; fi; " \
> >>> +		"if test $beaglerev = xMC; then " \
> >>> +			"setenv fdtfile omap3-beagle-xm.dtb; fi; " \
> >>> +		"if test $fdtfile = undefined; then " \
> >>> +			"echo WARNING: Could not determine device tree to use; fi; \0" \
> >> 
> >> With the remote chance of a future xM rev D, can you make the
> >> fallthrough be 'omap3-beagle-xm.dtb' intead of 'undefined'?
> > 
> > I don't like that idea.  On am335x_evm configs we have undefined and
> > then say "hey, it's undefined!" so it's clear that we don't know what to
> > do.  That in theory future xM rev D might need a different device tree
> > for example.
> 
> And that's patched out on the build that actually ships with the
> beaglebone and beaglebone black so it will fall back to BBB when it
> can't ID the board. You'll see that the u-boot bits that need the ID
> for the xM also fallback to the latest rev. I don't see why the
> boardfile and script need to have different behaviour.

Yes, I'm not terribly happy with what gets done for the shipping U-Boot
on BBB, but I understand you're trying to not have too special of a
binary used in programming versus distribution of the board.  If the
vendor wants to ship software that says "when in doubt, it's likely this
board", that's OK for the vendor to do.

-- 
Tom
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