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

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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



[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [Linux for Sparc]     [IETF Annouce]     [Security]     [Bugtraq]     [Linux MIPS]     [ECOS]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux