On Wed, Apr 10, 2024 at 12:06:29PM +0300, Tomi Valkeinen wrote: > On 08/04/2024 20:04, Ville Syrjala wrote: > > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > > > __iowmb() isn't available on most architectures. Make > > its use optional so that the driver can be built on > > other architectures with COMPILE_TEST=y. > > > > Cc: Jyri Sarha <jyri.sarha@xxxxxx> > > Cc: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx> > > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > --- > > drivers/gpu/drm/tilcdc/tilcdc_regs.h | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/drivers/gpu/drm/tilcdc/tilcdc_regs.h b/drivers/gpu/drm/tilcdc/tilcdc_regs.h > > index f90e2dc3457c..44e4ada30fba 100644 > > --- a/drivers/gpu/drm/tilcdc/tilcdc_regs.h > > +++ b/drivers/gpu/drm/tilcdc/tilcdc_regs.h > > @@ -125,7 +125,9 @@ static inline void tilcdc_write64(struct drm_device *dev, u32 reg, u64 data) > > #if defined(iowrite64) && !defined(iowrite64_is_nonatomic) > > iowrite64(data, addr); > > #else > > +#ifdef __iowmb > > __iowmb(); > > +#endif > > /* This compiles to strd (=64-bit write) on ARM7 */ > > *(volatile u64 __force *)addr = __cpu_to_le64(data); > > #endif > > As the memory barrier is an important part there, would it be better to > ifdef based on COMPILE_TEST, to make it clear why it's being done? I can do that if you prefer. I suppose the real question is why iowrite64() doesn't work if a hand rolled version does work? -- Ville Syrjälä Intel
