Hi Geert,
On Fri, Sep 14, 2018 at 01:35:22PM +0200, Geert Uytterhoeven wrote:
> Hi Angelo,
>
> Thanks for your patch!
>
> On Fri, Sep 14, 2018 at 9:12 AM Angelo Dureghello <angelo@xxxxxxxx> wrote:
> > This patch fixes the compilation warning reported
> > during x86_64 allmodconfig build.
>
> Please quote the warning, so people know what it is about:
>
> drivers/dma/mcf-edma.c: In function 'mcf_edma_filter_fn':
> drivers/dma/mcf-edma.c:296:33: warning: cast from pointer to
> integer of different size [-Wpointer-to-int-cast]
> return (mcf_chan->slave_id == (u32)param);
>
Ok done.
> > Reported-By: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> > Signed-off-by: Angelo Dureghello <angelo@xxxxxxxx>
> > ---
> > Changes for v2:
> > - added Reported-By
> > ---
> > drivers/dma/mcf-edma.c | 3 ++-
> > include/linux/platform_data/dma-mcf-edma.h | 2 +-
> > 2 files changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/dma/mcf-edma.c b/drivers/dma/mcf-edma.c
> > index 4d30d5302649..e08e2409a102 100644
> > --- a/drivers/dma/mcf-edma.c
> > +++ b/drivers/dma/mcf-edma.c
> > @@ -292,8 +292,9 @@ bool mcf_edma_filter_fn(struct dma_chan *chan, void *param)
> > {
> > if (chan->device->dev->driver == &mcf_edma_driver.driver) {
> > struct fsl_edma_chan *mcf_chan = to_fsl_edma_chan(chan);
> > + unsigned int req = *(unsigned int *)param;
>
> This looks a bit hackish to me.
> >
> > - return (mcf_chan->slave_id == (u32)param);
>
> The recommended way to cast from pointers to integers is to
> use uintptr_t, which always has the same size as a pointer, i.e.:
>
slave_id is acually an u32. So, if i understsand, when compiled
on x86_64 using uintptr_t, the cast should trigger the same issue.
I preferred, as i.e. ti/omap dma driver is doing, to simply
use a pointer to an int (int[]) as passed type in param,
so i can then indirectly access the integer. I tested
proper functionality in ColdFire and that there are no warnings
anymore in both ColdFire and x86_64 allmodconfig so the patch,
hopefully, should be legal.
> return (mcf_chan->slave_id == (uintptr_t)param);
>
> > + return (mcf_chan->slave_id == req);
> > }
> >
> > return false;
> > diff --git a/include/linux/platform_data/dma-mcf-edma.h b/include/linux/platform_data/dma-mcf-edma.h
> > index d718ccfa3421..97cb79bda646 100644
> > --- a/include/linux/platform_data/dma-mcf-edma.h
> > +++ b/include/linux/platform_data/dma-mcf-edma.h
> > @@ -21,7 +21,7 @@ struct dma_slave_map;
> >
> > bool mcf_edma_filter_fn(struct dma_chan *chan, void *param);
> >
> > -#define MCF_EDMA_FILTER_PARAM(ch) ((void *)ch)
> > +#define MCF_EDMA_FILTER_PARAM(ch) ((int[]) { (ch) })
> >
> > /**
> > * struct mcf_edma_platform_data - platform specific data for eDMA engine
>
> Gr{oetje,eeting}s,
>
> Geert
>
Regards,
Angelo
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
> -- Linus Torvalds
