[U-Boot] [PATCH] ddr:fsl: Fix warnings on gcc-6.x

[Tom Rini <trini@konsulko.com>]

On Fri, Feb 10, 2017 at 04:45:12PM +0000, york sun wrote:
> On 02/09/2017 03:10 PM, Tom Rini wrote:
> > With gcc-6.x we will see many warnings like:
> > warning: ?dual_0S? defined but not used [-Wunused-const-variable=]
> >
> > Depending on exactly what DDR choices are or are not enabled when we use
> > this file.  So we use slightly more exact #ifdef tests in order to
> > silence the warnings.
> >
> > Reported-by: Thomas Schaefer <Thomas.Schaefer@kontron.com>
> > Cc: York Sun <york.sun@nxp.com>
> > Signed-off-by: Tom Rini <trini@konsulko.com>
> > ---
> >  drivers/ddr/fsl/options.c | 27 ++++++++++++++++++++++++---
> >  1 file changed, 24 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/ddr/fsl/options.c b/drivers/ddr/fsl/options.c
> > index d6a8fcb216a4..7f7c16ced6f3 100644
> > --- a/drivers/ddr/fsl/options.c
> > +++ b/drivers/ddr/fsl/options.c
> > @@ -29,10 +29,12 @@ struct dynamic_odt {
> >  	unsigned int odt_rtt_wr;
> >  };
> >
> > -#ifdef CONFIG_SYS_FSL_DDR4
> > +#if defined(CONFIG_SYS_FSL_DDR4) && defined(CONFIG_DIMM_SLOTS_PER_CTLR)
> >  /* Quad rank is not verified yet due availability.
> >   * Replacing 20 OHM with 34 OHM since DDR4 doesn't have 20 OHM option
> >   */
> > +#if (CONFIG_DIMM_SLOTS_PER_CTLR == 1) || ((CONFIG_DIMM_SLOTS_PER_CTLR == 2) && \
> > +				defined(CONFIG_FSL_DDR_FIRST_SLOT_QUAD_CAPABLE))
> >  static const struct dynamic_odt single_Q[4] = {
> >  	{	/* cs0 */
> >  		FSL_DDR_ODT_NEVER,
> > @@ -59,7 +61,9 @@ static const struct dynamic_odt single_Q[4] = {
> >  		DDR4_RTT_120_OHM
> >  	}
> >  };
> > +#endif
> >
> > +#if (CONFIG_DIMM_SLOTS_PER_CTLR == 1)
> >  static const struct dynamic_odt single_D[4] = {
> >  	{	/* cs0 */
> >  		FSL_DDR_ODT_NEVER,
> > @@ -89,6 +93,8 @@ static const struct dynamic_odt single_S[4] = {
> >  	{0, 0, 0, 0},
> >  };
> >
> > +#elif (CONFIG_DIMM_SLOTS_PER_CTLR == 2)
> > +
> 
> <snip>
> 
> Tom,
> 
> What do you think about using __maybe_unused instead? As Thomas Schaefer 
> has verified that GCC optimized out unused constants.

Yeah, that ends up being clearer I think esp since we're not concerned
with the data being included by accident.  Thanks!

-- 
Tom
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