Re: [PATCH 01/02] ARM: shmobile: Add shared R-Car Gen2 CMA reservation code

[Simon Horman <horms@verge.net.au>]

On Tue, Jun 10, 2014 at 07:51:38PM +0900, Magnus Damm wrote:
> Hi Geert,
> 
> Thanks for your feedback!
> 
> On Tue, Jun 10, 2014 at 4:19 PM, Geert Uytterhoeven
> <geert@linux-m68k.org> wrote:
> > Hi Magnus,
> >
> > On Mon, Jun 9, 2014 at 2:38 PM, Magnus Damm <magnus.damm@gmail.com> wrote:
> >> --- 0001/arch/arm/mach-shmobile/setup-rcar-gen2.c
> >> +++ work/arch/arm/mach-shmobile/setup-rcar-gen2.c       2014-06-09 21:01:33.000000000 +0900
> >
> >> +static int __init rcar_gen2_scan_mem(unsigned long node, const char *uname,
> >> +                                    int depth, void *data)
> >> +{
> >
> >> +       u64 lpae_start = (u64)1 << 32;
> >
> > Casts are evil:
> >
> > 1ULL << 32
> >
> > (I hope one day gcc will gain a "-Wcast" option, so we can easily find and
> >  inspect all casts, as C-style casts are much more difficult to grep for than
> >  C++-style casts).
> 
> Oh, right, I totally forgot I added that one. =)
> 
> >> +       /* We are scanning "memory" nodes only */
> >> +       if (type = NULL) {
> >> +               /*
> >> +                * The longtrail doesn't have a device_type on the
> >> +                * /memory node, so look for the node called /memory@0.
> >> +                */
> >> +               if (depth != 1 || strcmp(uname, "memory@0") != 0)
> >> +                       return 0;
> >
> > AFAIK Open Firmware in the LongTrail does not support plugging in ARM CPUs
> > in its PPC 603e/604e-compatible CPU socket ;-)
> 
> You never know - anything is possible with DT. =)
> 
> But yes, I get your point - will clean up.
> 
> >> +struct cma *rcar_gen2_dma_contiguous;
> >> +
> >> +void __init rcar_gen2_reserve(void)
> >> +{
> >
> >> +#ifdef CONFIG_DMA_CMA
> >> +       if (mrc.size)
> >> +               dma_contiguous_reserve_area(mrc.size, mrc.base, 0,
> >> +                                           &rcar_gen2_dma_contiguous);
> >> +#endif
> >
> > I assume one day rcar_gen2_dma_contiguous will become used?
> 
> That's the idea, yes!
> 
> Since Simon kindly queued this up already I will submit an incremental
> fix to deal with the issues that you pointed out.

Thanks. FWIW I quite dislike casts.