Messages in this thread | | | Date | Mon, 6 Dec 2021 16:42:01 +0530 | Subject | Re: [PATCHv5 1/4] arm64: io: Use asm-generic high level MMIO accessors | From | Sai Prakash Ranjan <> |
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On 12/6/2021 2:20 PM, Arnd Bergmann wrote: > On Mon, Dec 6, 2021 at 9:28 AM Sai Prakash Ranjan > <quic_saipraka@quicinc.com> wrote: >> Remove custom arm64 MMIO accessors read{b,w,l,q} and their relaxed >> versions in support to use asm-generic ones. Also define arm64 >> barrier macros to override the asm-generic defined barriers. >> >> Suggested-by: Arnd Bergmann <arnd@arndb.de> >> Signed-off-by: Sai Prakash Ranjan <quic_saipraka@quicinc.com> > This looks correct, but I would change one detail: > >> +#define __io_ar(v) __io_par(v) >> +#define __io_bw() __iowmb() >> +#define __io_br(v) >> +#define __io_aw(v) > The default __io_par() is defined in terms of __io_ar(), so it would > be more logical > to remove the custom __io_par() and just define __io_ar() here.
Makes sense, will do this.
> 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?
Thanks, Sai
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