[RFC] gen-dtb-s: make metadata binary fields always little-endian

[Uwe Kleine-König]

On Sun, Aug 03, 2014 at 09:53:38PM +0400, Antony Pavlov wrote:
> On Sun, 03 Aug 2014 18:17:45 +0200
> Jan Lübbe <jlu at pengutronix.de> wrote:
> 
> > Hi,
> > 
> > On Sat, 2014-08-02 at 09:45 +0400, Antony Pavlov wrote:
> > >  
> > >                 compatlen=$($FDTGET -t s "$dtb" / compatible | wc -c)
> > > -               echo ".int 0x640c8005"
> > > -               echo ".int " $compatlen
> > > +               echo ".byte 0x05, 0x80, 0x0c, 0x64"
> > > +               python -c "print(\".byte 0x%02x, 0x%02x, 0x%02x, 0x%02x\\n\" % ($compatlen & 0xff, ($compatlen >> 8) & 0xff, ($compatlen >> 16) & 0xff, ($compatlen >> 24) & 0xff))"
> > 
> > Rather than adding a build-time dependency on python, maybe we should
> > just handle this in C?
> 
> We use sphinx for documentation generation so we already have dependency on python.
> 
> Here is an another solution:
> 
> -               echo ".int " $compatlen
> +		echo ".byte " $(printf "%08x" $compatlen | sed "s/\(..\)/0x\1\n/g" | tac | xargs | sed "s/ /, /g")
yet another alternative:

awk -v var=$compatlen 'BEGIN { for (i = 0; i < 4; ++i) ba[i] = and(rshift(var, 8 * i), 0xff); printf ".byte 0x%02x, 0x%02x, 0x%02x, 0x%02x\n", ba[0], ba[1], ba[2], ba[3]; }'

It's not shorter, but maybe a bit more obvious what it does.

Best regards
Uwe

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