[U-Boot] [PATCH] sc520: fix build warning about unused temp var

[Mike Frysinger <vapier@gentoo.org>]

On Monday 05 March 2012 17:31:43 Graeme Russ wrote:
> On Tue, Mar 6, 2012 at 8:55 AM, Mike Frysinger wrote:
> > Building the eNET_SRAM board fails for me:
> >        sc520_timer.c: In function 'sc520_udelay':
> >        sc520_timer.c:81:7: error: variable 'temp' set but not used
> >                [-Werror=unused-but-set-variable]
> >        cc1: all warnings being treated as errors
> >        make[1]: *** [sc520_timer.o] Error 1
> > 
> > Signed-off-by: Mike Frysinger <vapier@gentoo.org>
> > ---
> >  arch/x86/cpu/sc520/sc520_timer.c |    5 ++---
> >  1 files changed, 2 insertions(+), 3 deletions(-)
> > 
> > diff --git a/arch/x86/cpu/sc520/sc520_timer.c
> > b/arch/x86/cpu/sc520/sc520_timer.c index 495a694..41f121f 100644
> > --- a/arch/x86/cpu/sc520/sc520_timer.c
> > +++ b/arch/x86/cpu/sc520/sc520_timer.c
> > @@ -78,10 +78,9 @@ void sc520_udelay(unsigned long usec)
> >  {
> >        int m = 0;
> >        long u;
> > -       long temp;
> > 
> > -       temp = readw(&sc520_mmcr->swtmrmilli);
> > -       temp = readw(&sc520_mmcr->swtmrmicro);
> > +       readw(&sc520_mmcr->swtmrmilli);
> > +       readw(&sc520_mmcr->swtmrmicro);
> > 
> >        do {
> >                m += readw(&sc520_mmcr->swtmrmilli);
> 
> I really appreciate the effort you (and others) have put into fixing this
> and I really should have made a more formal response earlier (sorry), but
> here goes...
> 
> Although this will fix the build warning, the actual implementation of
> sc520_udelay is wrong and can produce a timeout which is up to 1000us
> short (which I think we can all agree is a bad thing). On top of this,
> there is an sc520 silicon bug which means even a technically correct
> software implementation may produce erroneous results (although from
> memory that produces a timeout which could be 1000us long which is
> better than a short timeout)
> 
> And then there is the fact that this is a depricated platform - There is
> only one physical sc520 board which U-Boot has ever been loaded onto and
> that is buried on a shelf in my study somewhere - I'm working on another
> x86 board at the moment, but I'm not at liberty to release the code yet.
> As soon as that is released, I'm going to remove the sc520 anyway
> 
> So do I apply this to fix the build warning knowing there is another more
> serious bug and knowing this arch is getting scrapped soon, or do I just
> leave it as is?

considering this warning breaks `MAKEALL` testing, it's adding noise to people 
trying to verify their own unrelated changes.  so yes, i think this fix should 
be merged, or the code dropped.  leaving it in between is negatively affecting 
others.
-mike
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