Re: Re: [PATCH] fbdev: Fix IO access in rivafb

[Guido Guenther <agx@sigxcpu.org>]

On Mon, Nov 08, 2004 at 02:25:04PM -0800, Linus Torvalds wrote:
> 
> 
> On Tue, 9 Nov 2004, Antonino A. Daplas wrote:
> > 
> > In big endian machines, the read*/write* accessors do a byteswap for an
> > inherently little endian PCI bus.  However, rivafb puts the hardwire in big
> > endian register access, thus the byteswap is not needed. So for 16- and
> > 32-bit access, instead of read*/write*, use __raw_read*/__raw_write* for all
> > archs.
> 
> Ok, applied with some further simplifications (use "void __iomem *" and 
> suddenly those /2 and /4 just go away - also use __raw_xxxx for the 
> single-byte versions to be consistent).
Doesn't work for me. This one works:

diff -u -u linux-2.6.10-rc1-mm5.orig/drivers/video/riva/riva_hw.h linux-2.6.10-rc1-mm5/drivers/video/riva/riva_hw.h
--- linux-2.6.10-rc1-mm5.orig/drivers/video/riva/riva_hw.h	2004-11-12 13:42:54.000000000 +0100
+++ linux-2.6.10-rc1-mm5/drivers/video/riva/riva_hw.h	2004-11-12 13:47:29.400807920 +0100
@@ -75,12 +75,12 @@
  */
 #include <asm/io.h>
 
-#define NV_WR08(p,i,d)  (__raw_writeb((d), (void __iomem *)(p) + (i)))
-#define NV_RD08(p,i)    (__raw_readb((void __iomem *)(p) + (i)))
-#define NV_WR16(p,i,d)  (__raw_writew((d), (void __iomem *)(p) + (i)))
-#define NV_RD16(p,i)    (__raw_readw((void __iomem *)(p) + (i)))
-#define NV_WR32(p,i,d)  (__raw_writel((d), (void __iomem *)(p) + (i)))
-#define NV_RD32(p,i)    (__raw_readl((void __iomem *)(p) + (i)))
+#define NV_WR08(p,i,d)  (writeb((d), (u8 __iomem *)(p) + (i)))
+#define NV_RD08(p,i)    (readb((u8 __iomem *)(p) + (i)))
+#define NV_WR16(p,i,d)  (__raw_writew((d), (u16 __iomem *)(p) + (i)/2))
+#define NV_RD16(p,i)    (__raw_readw((u16 __iomem *)(p) + (i)/2))
+#define NV_WR32(p,i,d)  (__raw_writel((d), (u32 __iomem *)(p) + (i)/4))
+#define NV_RD32(p,i)    (__raw_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)

Interesting enough this one doesn't (only differenc in NV_{WR,RW}08:

diff -u -u linux-2.6.10-rc1-mm5.orig/drivers/video/riva/riva_hw.h linux-2.6.10-rc1-mm5/drivers/video/riva/riva_hw.h
--- linux-2.6.10-rc1-mm5.orig/drivers/video/riva/riva_hw.h	2004-11-12 13:42:54.000000000 +0100
+++ linux-2.6.10-rc1-mm5/drivers/video/riva/riva_hw.h	2004-11-12 13:47:29.400807920 +0100
@@ -75,12 +75,12 @@
  */
 #include <asm/io.h>
 
-#define NV_WR08(p,i,d)  (__raw_writeb((d), (void __iomem *)(p) + (i)))
-#define NV_RD08(p,i)    (__raw_readb((void __iomem *)(p) + (i)))
-#define NV_WR16(p,i,d)  (__raw_writew((d), (void __iomem *)(p) + (i)))
-#define NV_RD16(p,i)    (__raw_readw((void __iomem *)(p) + (i)))
-#define NV_WR32(p,i,d)  (__raw_writel((d), (void __iomem *)(p) + (i)))
-#define NV_RD32(p,i)    (__raw_readl((void __iomem *)(p) + (i)))
+#define NV_WR08(p,i,d)  (writeb((d), (u8 __iomem *)(p) + (i)))
+#define NV_RD08(p,i)    (readb((u8 __iomem *)(p) + (i)))
+#define NV_WR16(p,i,d)  (__raw_writew((d), (u16 __iomem *)(p) + (i)/2))
+#define NV_RD16(p,i)    (__raw_readw((u16 __iomem *)(p) + (i)/2))
+#define NV_WR32(p,i,d)  (__raw_writel((d), (u32 __iomem *)(p) + (i)/4))
+#define NV_RD32(p,i)    (__raw_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)

Cheers,
 -- Guido


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