Re: [RFC] drivers: brcmaxi: provide amba axi functionality in separate module

["Arend van Spriel" <arend@broadcom.com>]

On Wed, 23 Mar 2011 14:49:43 +0100, Michael Büsch <mb@bu3sch.de> wrote:

>
>> void foobar(void *r, u32 val)
>> {
>>     volatile u32 dummy;
>>
>>     WR_REG(r, val);
>>     dummy = RD_REG(r);
>> }
>>
>> The register read is necessary to assure the register write is properly
>> flushed out in hardware. Could removing the volatile for the dummy
>> variable cause removal of the register read due to code optimization.
>
> It shouldn't optimize the read away as long as the RD_REG uses a  
> volatile pointer internally. Which is the case if you use readl/w/b or  
> ioread... to implement RD_REG

Well, RD_REG(r) is a macro which translates to readb((volatile u8*)r). Are  
you referring to that being a volatile pointer or do you mean that inside  
the accessor function readb the 'r' parameter is treated as a volatile  
pointer.

Gr. AvS
-- 
"The most merciful thing in the world, I think, is the inability of the  
human
mind to correlate all its contents." - "The Call of Cthulhu"