Re: [PATCH v2] locking/memory-barriers.txt: Improve documentation for writel() example

[Bagas Sanjaya]

On 10/5/22 17:47, Parav Pandit wrote:
> @@ -1927,10 +1927,12 @@ There are some more advanced barrier functions:
>       before we read the data from the descriptor, and the dma_wmb() allows
>       us to guarantee the data is written to the descriptor before the device
>       can see it now has ownership.  The dma_mb() implies both a dma_rmb() and
> -     a dma_wmb().  Note that, when using writel(), a prior wmb() is not needed
> -     to guarantee that the cache coherent memory writes have completed before
> -     writing to the MMIO region.  The cheaper writel_relaxed() does not provide
> -     this guarantee and must not be used here.
> +     a dma_wmb().  Note that, when using writel(), a prior barrier is not
> +     needed to guarantee that the cache coherent memory writes have completed
> +     before writing to the MMIO region.  The cheaper writel_relaxed() does not
> +     provide this guarantee and must not be used here. Hence, writeX() is always
> +     preferred which inserts needed platform specific barrier before writing to
> +     the specified MMIO region.
>  

Did you mean that writeX() is write() function family?

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