From: "Antonino A. Daplas" <adaplas@hotpop.com>
Reply-To: adaplas@pol.net
To: linux-fbdev-devel@lists.sourceforge.net,
       Benjamin Herrenschmidt <benh@kernel.crashing.org>,
       Linux Kernel list <linux-kernel@vger.kernel.org>
Subject: Re: [Linux-fbdev-devel] Re: [PATCH] fbdev: Fix IO access in rivafb
Date: Mon, 8 Nov 2004 17:06:54 +0800
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Cc: Linux Fbdev development list 
	<linux-fbdev-devel@lists.sourceforge.net>,
       Andrew Morton <akpm@osdl.org>, Linus Torvalds <torvalds@osdl.org>
References: <200411080521.iA85LbG6025914@hera.kernel.org> <1099893447.10262.154.camel@gaston>
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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@pol.net>
---

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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