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| author | Maciej W. Rozycki <macro@linux-mips.org> | 2018-10-08 03:37:23 +0300 |
|---|---|---|
| committer | Paul Burton <paul.burton@mips.com> | 2018-10-09 20:44:29 +0300 |
| commit | 8b656253a7a4526f413f6b5ad0b03e11daa1d62d (patch) | |
| tree | d95f1b05680681dfb63c43250611810ae3f351f6 /arch/mips | |
| parent | 3d474dacae72ac0f28228b328cfa953b05484b7f (diff) | |
| download | linux-8b656253a7a4526f413f6b5ad0b03e11daa1d62d.tar.xz | |
MIPS: Provide actually relaxed MMIO accessors
Improve performance for the relevant systems and remove the DMA ordering
barrier from `readX_relaxed' and `writeX_relaxed' MMIO accessors, where
it is not needed according to our requirements[1]. For consistency make
the same arrangement with low-level port I/O accessors, but do not
actually provide any accessors making use of it.
References:
[1] "LINUX KERNEL MEMORY BARRIERS", Documentation/memory-barriers.txt,
Section "KERNEL I/O BARRIER EFFECTS"
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20865/
Cc: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips')
| -rw-r--r-- | arch/mips/include/asm/io.h | 48 |
1 files changed, 28 insertions, 20 deletions
diff --git a/arch/mips/include/asm/io.h b/arch/mips/include/asm/io.h index 9833a67eb9e6..266257d56fb6 100644 --- a/arch/mips/include/asm/io.h +++ b/arch/mips/include/asm/io.h @@ -46,6 +46,11 @@ # define __raw_ioswabq(a, x) (x) # define ____raw_ioswabq(a, x) (x) +# define __relaxed_ioswabb ioswabb +# define __relaxed_ioswabw ioswabw +# define __relaxed_ioswabl ioswabl +# define __relaxed_ioswabq ioswabq + /* ioswab[bwlq], __mem_ioswab[bwlq] are defined in mangle-port.h */ #define IO_SPACE_LIMIT 0xffff @@ -311,7 +316,7 @@ static inline void iounmap(const volatile void __iomem *addr) #define war_io_reorder_wmb() barrier() #endif -#define __BUILD_MEMORY_SINGLE(pfx, bwlq, type, barrier, irq) \ +#define __BUILD_MEMORY_SINGLE(pfx, bwlq, type, barrier, relax, irq) \ \ static inline void pfx##write##bwlq(type val, \ volatile void __iomem *mem) \ @@ -385,11 +390,12 @@ static inline type pfx##read##bwlq(const volatile void __iomem *mem) \ } \ \ /* prevent prefetching of coherent DMA data prematurely */ \ - rmb(); \ + if (!relax) \ + rmb(); \ return pfx##ioswab##bwlq(__mem, __val); \ } -#define __BUILD_IOPORT_SINGLE(pfx, bwlq, type, barrier, p) \ +#define __BUILD_IOPORT_SINGLE(pfx, bwlq, type, barrier, relax, p) \ \ static inline void pfx##out##bwlq##p(type val, unsigned long port) \ { \ @@ -426,19 +432,21 @@ static inline type pfx##in##bwlq##p(unsigned long port) \ __val = *__addr; \ \ /* prevent prefetching of coherent DMA data prematurely */ \ - rmb(); \ + if (!relax) \ + rmb(); \ return pfx##ioswab##bwlq(__addr, __val); \ } -#define __BUILD_MEMORY_PFX(bus, bwlq, type) \ +#define __BUILD_MEMORY_PFX(bus, bwlq, type, relax) \ \ -__BUILD_MEMORY_SINGLE(bus, bwlq, type, 1, 1) +__BUILD_MEMORY_SINGLE(bus, bwlq, type, 1, relax, 1) #define BUILDIO_MEM(bwlq, type) \ \ -__BUILD_MEMORY_PFX(__raw_, bwlq, type) \ -__BUILD_MEMORY_PFX(, bwlq, type) \ -__BUILD_MEMORY_PFX(__mem_, bwlq, type) \ +__BUILD_MEMORY_PFX(__raw_, bwlq, type, 0) \ +__BUILD_MEMORY_PFX(__relaxed_, bwlq, type, 1) \ +__BUILD_MEMORY_PFX(__mem_, bwlq, type, 0) \ +__BUILD_MEMORY_PFX(, bwlq, type, 0) BUILDIO_MEM(b, u8) BUILDIO_MEM(w, u16) @@ -446,8 +454,8 @@ BUILDIO_MEM(l, u32) BUILDIO_MEM(q, u64) #define __BUILD_IOPORT_PFX(bus, bwlq, type) \ - __BUILD_IOPORT_SINGLE(bus, bwlq, type, 1,) \ - __BUILD_IOPORT_SINGLE(bus, bwlq, type, 1, _p) + __BUILD_IOPORT_SINGLE(bus, bwlq, type, 1, 0,) \ + __BUILD_IOPORT_SINGLE(bus, bwlq, type, 1, 0, _p) #define BUILDIO_IOPORT(bwlq, type) \ __BUILD_IOPORT_PFX(, bwlq, type) \ @@ -462,19 +470,19 @@ BUILDIO_IOPORT(q, u64) #define __BUILDIO(bwlq, type) \ \ -__BUILD_MEMORY_SINGLE(____raw_, bwlq, type, 1, 0) +__BUILD_MEMORY_SINGLE(____raw_, bwlq, type, 1, 0, 0) __BUILDIO(q, u64) -#define readb_relaxed readb -#define readw_relaxed readw -#define readl_relaxed readl -#define readq_relaxed readq +#define readb_relaxed __relaxed_readb +#define readw_relaxed __relaxed_readw +#define readl_relaxed __relaxed_readl +#define readq_relaxed __relaxed_readq -#define writeb_relaxed writeb -#define writew_relaxed writew -#define writel_relaxed writel -#define writeq_relaxed writeq +#define writeb_relaxed __relaxed_writeb +#define writew_relaxed __relaxed_writew +#define writel_relaxed __relaxed_writel +#define writeq_relaxed __relaxed_writeq #define readb_be(addr) \ __raw_readb((__force unsigned *)(addr)) |