On 23:28 Tue 07 Jul , Wolfgang Denk wrote:
Dear Jean-Christophe PLAGNIOL-VILLARD,
In message 20090707202432.GK30172@game.jcrosoft.org you wrote:
- These macros provide a convenient way to write 8, 16 and 32 bit data
- to any address.
I think this comment might be wrong. It should probably read "... to any _memory_ address". Using these macros to access device registers and the like is probably nore recommended?
you can access cpu register without problem with these macros
Is it guaranteed that none of the existing ARM architectures and all the plethora of their specific implementations of the zillions of SoCs do not require any form of memory barrier instructions when accessing device registers? Even when these are external peripherals on some external bus?
Sorry for such a stupid question about things that are eventually obvious to you, but I don't know ARM processors that well...
you may need it in specific case as cache, tlb, co-processor or smp otherwise you do not need it
so normaly no-need for register access
Best Regards, J.