| Message ID | 20150506104504.GM2067@n2100.arm.linux.org.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, 6 May 2015, Russell King - ARM Linux wrote: > On Tue, Apr 28, 2015 at 11:28:53AM -0400, Nicolas Pitre wrote: > > On Tue, 28 Apr 2015, Russell King - ARM Linux wrote: > > > > > On Fri, Apr 24, 2015 at 03:46:56PM +0200, Geert Uytterhoeven wrote: > > > > So please optimize ARM's _memcpy_fromio(), _memcpy_toio(), and _memset_io(). > > > > That will benefit other drivers on ARM, too. > > > > > > That's not going to happen. > > > > > > I've had a patch which does that, but people are concerned that it changes > > > the behaviour of the functions by changing the access size, which could > > > cause regressions. It seems people are far too worried about that to even > > > consider trying. :( > > > > What about making the optimized implementation available via kconfig? > > I'd prefer not to. My personal feeling is to put the patch in and just be > done with it - these functions are supposed to be used on IO areas which > don't care about access size (in other words, are memory-like rather than > being register-like.) Here's the rather old patch: > > From: Russell King <rmk+kernel@arm.linux.org.uk> > Subject: [PATCH] ARM: optimize memset_io()/memcpy_fromio()/memcpy_toio() > > If we are building for a LE platform, and we haven't overriden the > MMIO ops, then we can optimize the mem*io operations using the > standard string functions. > > Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Nicolas Pitre <nico@linaro.org> > --- > arch/arm/include/asm/io.h | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h > index d070741b2b37..358c8206419b 100644 > --- a/arch/arm/include/asm/io.h > +++ b/arch/arm/include/asm/io.h > @@ -23,6 +23,7 @@ > > #ifdef __KERNEL__ > > +#include <linux/string.h> > #include <linux/types.h> > #include <asm/byteorder.h> > #include <asm/memory.h> > @@ -312,9 +313,33 @@ extern void _memset_io(volatile void __iomem *, int, size_t); > #define writesw(p,d,l) __raw_writesw(p,d,l) > #define writesl(p,d,l) __raw_writesl(p,d,l) > > +#ifndef __ARMBE__ > +static inline void memset_io(volatile void __iomem *dst, unsigned c, > + size_t count) > +{ > + memset((void __force *)dst, c, count); > +} > +#define memset_io(dst,c,count) memset_io(dst,c,count) > + > +static inline void memcpy_fromio(void *to, const volatile void __iomem *from, > + size_t count) > +{ > + memcpy(to, (const void __force *)from, count); > +} > +#define memcpy_fromio(to,from,count) memcpy_fromio(to,from,count) > + > +static inline void memcpy_toio(volatile void __iomem *to, const void *from, > + size_t count) > +{ > + memcpy((void __force *)to, from, count); > +} > +#define memcpy_toio(to,from,count) memcpy_toio(to,from,count) > + > +#else > #define memset_io(c,v,l) _memset_io(c,(v),(l)) > #define memcpy_fromio(a,c,l) _memcpy_fromio((a),c,(l)) > #define memcpy_toio(c,a,l) _memcpy_toio(c,(a),(l)) > +#endif > > #endif /* readl */ > > -- > 1.8.3.1 > > > > -- > FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up > according to speedtest.net. > > -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed 2015-05-06 11:45:04, Russell King - ARM Linux wrote: > On Tue, Apr 28, 2015 at 11:28:53AM -0400, Nicolas Pitre wrote: > > On Tue, 28 Apr 2015, Russell King - ARM Linux wrote: > > > > > On Fri, Apr 24, 2015 at 03:46:56PM +0200, Geert Uytterhoeven wrote: > > > > So please optimize ARM's _memcpy_fromio(), _memcpy_toio(), and _memset_io(). > > > > That will benefit other drivers on ARM, too. > > > > > > That's not going to happen. > > > > > > I've had a patch which does that, but people are concerned that it changes > > > the behaviour of the functions by changing the access size, which could > > > cause regressions. It seems people are far too worried about that to even > > > consider trying. :( > > > > What about making the optimized implementation available via kconfig? > > I'd prefer not to. My personal feeling is to put the patch in and just be > done with it - these functions are supposed to be used on IO areas which > don't care about access size (in other words, are memory-like rather than > being register-like.) Here's the rather old patch: > > From: Russell King <rmk+kernel@arm.linux.org.uk> > Subject: [PATCH] ARM: optimize memset_io()/memcpy_fromio()/memcpy_toio() > > If we are building for a LE platform, and we haven't overriden the > MMIO ops, then we can optimize the mem*io operations using the > standard string functions. > > Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Tested-by: Pavel Machek <pavel@ucw.cz> Acked-by: Pavel Machek <pavel@ucw.cz> Works for me, framebuffer performance is back in "too fast to measure" range. When this is merged, should 981409b25e2a99409b26daa67293ca1cfd5ea0a0 be reverted in -stable? Thanks, Pavel
diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h index d070741b2b37..358c8206419b 100644 --- a/arch/arm/include/asm/io.h +++ b/arch/arm/include/asm/io.h @@ -23,6 +23,7 @@ #ifdef __KERNEL__ +#include <linux/string.h> #include <linux/types.h> #include <asm/byteorder.h> #include <asm/memory.h> @@ -312,9 +313,33 @@ extern void _memset_io(volatile void __iomem *, int, size_t); #define writesw(p,d,l) __raw_writesw(p,d,l) #define writesl(p,d,l) __raw_writesl(p,d,l) +#ifndef __ARMBE__ +static inline void memset_io(volatile void __iomem *dst, unsigned c, + size_t count) +{ + memset((void __force *)dst, c, count); +} +#define memset_io(dst,c,count) memset_io(dst,c,count) + +static inline void memcpy_fromio(void *to, const volatile void __iomem *from, + size_t count) +{ + memcpy(to, (const void __force *)from, count); +} +#define memcpy_fromio(to,from,count) memcpy_fromio(to,from,count) + +static inline void memcpy_toio(volatile void __iomem *to, const void *from, + size_t count) +{ + memcpy((void __force *)to, from, count); +} +#define memcpy_toio(to,from,count) memcpy_toio(to,from,count) + +#else #define memset_io(c,v,l) _memset_io(c,(v),(l)) #define memcpy_fromio(a,c,l) _memcpy_fromio((a),c,(l)) #define memcpy_toio(c,a,l) _memcpy_toio(c,(a),(l)) +#endif #endif /* readl */