Date:   Tue, 21 Feb 2023 18:56:28 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc:     linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org, tsbogend@alpha.franken.de,
        mpe@ellerman.id.au, paul.walmsley@sifive.com, palmer@dabbelt.com,
        robh+dt@kernel.org, hch@lst.de, m.szyprowski@samsung.com,
        robin.murphy@arm.com
Subject: Re: [PATCH 1/7] MIPS: Remove DMA_PERDEV_COHERENT
Message-ID: <20230221175628.GB15247@lst.de>
References: <20230221124613.2859-1-jiaxun.yang@flygoat.com> <20230221124613.2859-2-jiaxun.yang@flygoat.com>
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On Tue, Feb 21, 2023 at 12:46:07PM +0000, Jiaxun Yang wrote:
> As now we are always managing DMA coherence on per dev bias,
> there is no need to have such option. And it's not selected
> by any platform.

I think the real point here is that this is dead code, so it can
obviously go away, but:

>  config MIPS_GENERIC_KERNEL
>  	bool "Generic board-agnostic MIPS kernel"
> -	select ARCH_HAS_SETUP_DMA_OPS
>  	select MIPS_GENERIC
>  	select BOOT_RAW
>  	select BUILTIN_DTB
> @@ -1079,11 +1078,6 @@ config FW_CFE
>  config ARCH_SUPPORTS_UPROBES
>  	bool

> @@ -1097,6 +1091,7 @@ config DMA_NONCOHERENT
>  	select ARCH_HAS_DMA_PREP_COHERENT
>  	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
>  	select ARCH_HAS_DMA_SET_UNCACHED
> +	select ARCH_HAS_SETUP_DMA_OPS

This is an unrelated und undocument change.  If you want to do it,
please do that as a separate patch with a commit log documenting
the rationale.