Re: [PATCHv5 1/4] arm64: io: Use asm-generic high level MMIO accessors

[Sai Prakash Ranjan]

On 12/6/2021 5:00 PM, Arnd Bergmann wrote:
> On Mon, Dec 6, 2021 at 12:12 PM Sai Prakash Ranjan
> <quic_saipraka@xxxxxxxxxxx> wrote:
> > On 12/6/2021 2:20 PM, Arnd Bergmann wrote:
> > > I think it would be even better to flip these around and make the low-level
> > > definitions __io_ar() and __io_bw(), and then defining the arm64 specific
> > > macros based on those:
> > >
> > > /* arm64-specific, don't use in portable drivers */
> > > #define __iormb(v)     __io_ar(v)
> > > #define __iowmb()      __io_bw()
> > > #define __iomb()        dma_mb()
> > So __iormb on arm64 has some dummy control dependency stuff as well based on
> > ("arm64: io: Ensure calls to delay routines are ordered against prior
> > readX()") and then we would need to change __iormb definition to __io_ar which
> > doesn't seem like __iormb definition to be exact right?
> I'm not sure what you are asking here. As far as I can tell, __io_ar()
> and __iormb() have the same calling conventions and the same barrier
> requirements, so they should be interchangeable, we just need to decide
> which one is the primary definition.
>
>         Arnd

Sorry, what I meant was the literal name of these macros, i.e., 
__iormb() has more explicit naming as
IO read memory barrier and __io_ar() is IO after read? So doesn't it 
make more sense that __iormb()
should be the primary definition which is already the case and ar/bw 
should be based on them.

Thanks,
Sai