Messages in this thread Patch in this message | | | Date | Fri, 21 Nov 2008 01:19:41 +0900 | From | Hitoshi Mitake <> | Subject | Re: [PATCH 1/1] edac x38: new MC driver module |
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On Tue, 18 Nov 2008 12:32:15 +0000 Russell King <rmk+lkml@arm.linux.org.uk> wrote:
> On Tue, Nov 18, 2008 at 12:16:20PM +0000, Ralf Baechle wrote: > > On Sun, Nov 09, 2008 at 11:26:46AM -0800, Andrew Morton wrote: > > > > > Perhaps it would be better to have a CONFIG_ARCH_HAS_READQ and to then > > > disable these drivers on the architectures which don't provide > > > readq/writeq support. > > > > And we also need to define the exact semantics. Questions coming to mind: > > > > o are implementations performing 2 32-bit accesses acceptable? > > o if so, what ordering for the two accesses is acceptable? > > and don't forget to document the semantics. If we're going to end up > with CONFIG_ARCH_HAS_READQ which architectures can select, I suggest > putting it in the help for that symbol. Why not another random file > in Documentation/ ? Because it's a random file in Documentation/ > that'll be overlooked when someone decided to select ARCH_HAS_READQ. > If it's along side the relevent config option, there is a higher > chance it will be noticed. >
Sorry for my late response...
I knew that implementing architecture-independed readq/writeq is too hard. To check that implementation is good for every architecture and test that readq/writeq are difficult works.
So I wrote patch in Andrew's way. This patch adds ARCH_HAS_READQ to X86_32 and X86_64, adds ARCH_HAS_WRITEQ to X86_64 and adds readq() to X86_32 (writeq is yet).
I want someone to review it. If this patch is good enough, I'll write help document and more patch adding ARCH_HAS_READQ and ARCH_HAS_WRITEQ to other architectre which has readq/writeq.
description of this patch: Adding config value to x86 architecture to determine existence of readq/writeq
Signed-off-by: Hitoshi Mitake <h.mitake@gmail.com> --- arch/x86/Kconfig | 3 +++ arch/x86/include/asm/io.h | 8 ++++++++ 2 files changed, 11 insertions(+), 0 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index ac22bb7..8f3c949 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -11,9 +11,12 @@ config 64BIT config X86_32 def_bool !64BIT + select ARCH_HAS_READQ config X86_64 def_bool 64BIT + select ARCH_HAS_READQ + select ARCH_HAS_WRITEQ ### Arch settings config X86 diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index ac2abc8..2a8fc26 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -57,6 +57,14 @@ build_mmio_write(__writeq, "q", unsigned long, "r", ) /* Let people know we have them */ #define readq readq #define writeq writeq + +#else /* CONFIG_X86_32 */ + +static inline unsigned long readq(const volatile void __iomem *addr) +{ + return readl(addr) | (((u64)readl(addr + 4)) << 32); +} + #endif extern int iommu_bio_merge; -- 1.5.6.5
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