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

[Arnd Bergmann]

On Mon, Dec 6, 2021 at 12:12 PM Sai Prakash Ranjan
<quic_saipraka at quicinc.com> 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