Re: [PATCH] fsldma: fsl_ioread64*() do not need lower_32_bits()

[Christophe Leroy]

Le 29/08/2020 à 17:05, Guenter Roeck a écrit :
> On Sat, Aug 29, 2020 at 02:45:38PM +0200, Luc Van Oostenryck wrote:
> > For ppc32, the functions fsl_ioread64() & fsl_ioread64be()
> > use lower_32_bits() as a fancy way to cast the pointer to u32
> > in order to do non-atomic 64-bit IO.
> >
> > But the pointer is already 32-bit, so simply cast the pointer to u32.
> >
> > This fixes a compile error introduced by
> >     ef91bb196b0d ("kernel.h: Silence sparse warning in lower_32_bits")
> >
> > Fixes: ef91bb196b0db1013ef8705367bc2d7944ef696b
>
> checkpatch complains about this and prefers
>
> Fixes: ef91bb196b0d ("kernel.h: Silence sparse warning in lower_32_bits")

Checkpatch also complains about spacing:

CHECK:SPACING: No space is necessary after a cast
#39: FILE: drivers/dma/fsldma.h:208:
+	u32 fsl_addr = (u32) addr;

CHECK:SPACING: No space is necessary after a cast
#48: FILE: drivers/dma/fsldma.h:222:
+	u32 fsl_addr = (u32) addr;

total: 0 errors, 0 warnings, 2 checks, 16 lines checked

Christophe

> Otherwise
>
> Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
>
> > Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> > Cc: Li Yang <leoyang.li@xxxxxxx>
> > Cc: Zhang Wei <zw@xxxxxxxxxxxxx>
> > Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
> > Cc: Vinod Koul <vkoul@xxxxxxxxxx>
> > Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> > Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
> > Cc: dmaengine@xxxxxxxxxxxxxxx
> > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
> > ---
> >   drivers/dma/fsldma.h | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/dma/fsldma.h b/drivers/dma/fsldma.h
> > index 56f18ae99233..6f6fa7641fa2 100644
> > --- a/drivers/dma/fsldma.h
> > +++ b/drivers/dma/fsldma.h
> > @@ -205,7 +205,7 @@ struct fsldma_chan {
> >   #else
> >   static u64 fsl_ioread64(const u64 __iomem *addr)
> >   {
> > -	u32 fsl_addr = lower_32_bits(addr);
> > +	u32 fsl_addr = (u32) addr;
> >   	u64 fsl_addr_hi = (u64)in_le32((u32 *)(fsl_addr + 1)) << 32;
> >   
> >   	return fsl_addr_hi | in_le32((u32 *)fsl_addr);
> > @@ -219,7 +219,7 @@ static void fsl_iowrite64(u64 val, u64 __iomem *addr)
> >   
> >   static u64 fsl_ioread64be(const u64 __iomem *addr)
> >   {
> > -	u32 fsl_addr = lower_32_bits(addr);
> > +	u32 fsl_addr = (u32) addr;
> >   	u64 fsl_addr_hi = (u64)in_be32((u32 *)fsl_addr) << 32;
> >   
> >   	return fsl_addr_hi | in_be32((u32 *)(fsl_addr + 1));
> > --
> > 2.28.0