Messages in this thread Patch in this message | | | From | "Antonino A. Daplas" <> | Subject | Re: [Linux-fbdev-devel] Re: [PATCH] fbdev: Fix IO access in rivafb | Date | Tue, 9 Nov 2004 06:08:02 +0800 |
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On Tuesday 09 November 2004 04:13, 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, instead > > of read*/write*, use __raw_read*/__raw_write*. > > This fix should make the #ifdef CONFIG_PCC entirely superfluous afaik.
Ah, of course.
> > The thing is, once riva does its HW accesses right, the special cases just > go away. There's a reason we have abstractions.. > > Does anybody have the hardware to test with? >
I've asked Guido Guenther to test, might take a couple of days. I also asked him if he can use the in/out_be* which is probably safer for ppc. And the mb()'s scattered all over the driver may be removed.
Tony
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.
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 2004-11-09 05:39:48 +08:00 +++ b/drivers/video/riva/riva_hw.h 2004-11-09 06:00:09 +08:00 @@ -73,18 +73,13 @@ /* * HW access macros. */ -#if defined(__powerpc__) #include <asm/io.h> -#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) (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)) +#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)
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