[PATCH] ARM: optimize memset_io()/memcpy_fromio()/memcpy_toio()

[dirk.behme@gmail.com (Dirk Behme)]

On 05.06.2013 08:02, Dirk Behme wrote:
> On 28.09.2012 00:02, Russell King wrote:
>> 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>
>> ---
>>   arch/arm/include/asm/io.h |   25 +++++++++++++++++++++++++
>>   1 files changed, 25 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
>> index 815c669..ed0577e 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>
>> @@ -249,9 +250,33 @@ 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 */
>
> I'd like to ask if there is any chance to get anything like this or
> the even older proposal
>
> http://lists.infradead.org/pipermail/linux-arm-kernel/2009-November/004077.html
>
>
> merged? Maybe an updated version incorporating the discussion
> conclusions?
>
>
> In the discussion of
>
> http://lists.infradead.org/pipermail/linux-arm-kernel/2009-November/004077.html
>
>
> there have been some doubts if it's a good idea to enable it for all
> SoCs. Therefore that patch introduced a
>
> config OPTIMIZED_IOMEM_MEMCPY
>
> which would allow us to enable it for only known to be compatible
> SoCs. Just in case this helps to get it applied ;)

Any opinion on this?

Best regards

Dirk