Re: [Linux-fbdev-devel] Re: [PATCH] fbdev: Fix IO access in rivafb

From: Antonino A. Daplas
Date: Mon Nov 08 2004 - 04:54:35 EST


On Monday 08 November 2004 13:57, Benjamin Herrenschmidt wrote:
> > diff -Nru a/drivers/video/riva/riva_hw.h b/drivers/video/riva/riva_hw.h
> > --- a/drivers/video/riva/riva_hw.h 2004-11-07 21:21:47 -08:00
> > +++ b/drivers/video/riva/riva_hw.h 2004-11-07 21:21:47 -08:00
> > @@ -78,13 +78,13 @@
> > #define NV_WR08(p,i,d) out_8(p+i, d)
> > #define NV_RD08(p,i) in_8(p+i)
> > #else
> > -#define NV_WR08(p,i,d) (((U008 *)(p))[i]=(d))
> > -#define NV_RD08(p,i) (((U008 *)(p))[i])
> > +#define NV_WR08(p,i,d) (writeb((d), (u8 __iomem *)(p) + (i)))
> > +#define NV_RD08(p,i) (readb((u8 __iomem *)(p) + (i)))
> > #endif
> > -#define NV_WR16(p,i,d) (((U016 *)(p))[(i)/2]=(d))
> > -#define NV_RD16(p,i) (((U016 *)(p))[(i)/2])
> > -#define NV_WR32(p,i,d) (((U032 *)(p))[(i)/4]=(d))
> > -#define NV_RD32(p,i) (((U032 *)(p))[(i)/4])
> > +#define NV_WR16(p,i,d) (writew((d), (u16 __iomem *)(p) + (i)/2))
> > +#define NV_RD16(p,i) (readw((u16 __iomem *)(p) + (i)/2))
> > +#define NV_WR32(p,i,d) (writel((d), (u32 __iomem *)(p) + (i)/4))
> > +#define NV_RD32(p,i) (readl((u32 __iomem *)(p) + (i)/4))
> > #define VGA_WR08(p,i,d) NV_WR08(p,i,d)
> > #define VGA_RD08(p,i) NV_RD08(p,i)
>
> You probably broke ppc versions here. The driver enables "big endian"
> register access, but readw/writew/l functions do byteswap, which will
> lead to incorrect results.
>
> The fix would be to probably just remove the code that puts the chip
> registers into big endian mode, this isn't necessary nor a very good
> idea actually.
>

How about this patch? This is almost the original macro in riva_hw.h,
with the __force annotation.

Signed-off-by: Antonino Daplas <adaplas@xxxxxxx>
---

diff -Nru a/drivers/video/riva/riva_hw.h b/drivers/video/riva/riva_hw.h
--- a/drivers/video/riva/riva_hw.h 2004-11-06 12:42:19 +08:00
+++ b/drivers/video/riva/riva_hw.h 2004-11-08 16:59:34 +08:00
@@ -77,14 +77,18 @@
#include <asm/io.h>
#define NV_WR08(p,i,d) out_8(p+i, d)
#define NV_RD08(p,i) in_8(p+i)
+#define NV_WR16(p,i,d) (((volatile u16 __force *)(p))[(i)/2]=(d))
+#define NV_RD16(p,i) (((volatile u16 __force *)(p))[(i)/2])
+#define NV_WR32(p,i,d) (((volatile u32 __force *)(p))[(i)/4]=(d))
+#define NV_RD32(p,i) (((volatile u32 __force *)(p))[(i)/4])
#else
#define NV_WR08(p,i,d) (writeb((d), (u8 __iomem *)(p) + (i)))
#define NV_RD08(p,i) (readb((u8 __iomem *)(p) + (i)))
-#endif
#define NV_WR16(p,i,d) (writew((d), (u16 __iomem *)(p) + (i)/2))
#define NV_RD16(p,i) (readw((u16 __iomem *)(p) + (i)/2))
#define NV_WR32(p,i,d) (writel((d), (u32 __iomem *)(p) + (i)/4))
#define NV_RD32(p,i) (readl((u32 __iomem *)(p) + (i)/4))
+#endif
#define VGA_WR08(p,i,d) NV_WR08(p,i,d)
#define VGA_RD08(p,i) NV_RD08(p,i)



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