Message-ID: <ed2d7750-786d-82a1-5e79-1f216a682b20@arm.com>
Date:   Tue, 21 Feb 2023 19:46:08 +0000
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Subject: Re: [PATCH 0/7] MIPS DMA coherence fixes
Content-Language: en-GB
To:     Jiaxun Yang <jiaxun.yang@flygoat.com>,
        Christoph Hellwig <hch@lst.de>
Cc:     "linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>,
        linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        mpe@ellerman.id.au, paul.walmsley@sifive.com, palmer@dabbelt.com,
        Rob Herring <robh+dt@kernel.org>, m.szyprowski@samsung.com
References: <20230221124613.2859-1-jiaxun.yang@flygoat.com>
 <20230221175423.GA15247@lst.de>
 <A8AC22A0-E883-4D9B-A629-5A3721B976C5@flygoat.com>
From:   Robin Murphy <robin.murphy@arm.com>
In-Reply-To: <A8AC22A0-E883-4D9B-A629-5A3721B976C5@flygoat.com>
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On 2023-02-21 18:15, Jiaxun Yang wrote:
> 
> 
>> 2023年2月21日 17:54，Christoph Hellwig <hch@lst.de> 写道：
>>
>> Can you explain the motivation here?  Also why riscv patches are at
>> the end of a mips fіxes series?
> 
> Ah sorry for any confusion.
> 
> So the main purpose of this patch is to fix MIPS’s broken per-device coherency.
> To be more precise, we want to be able to control the default coherency for all devices probed from
> devicetree in early boot code.

Including the patch which actually does that would be helpful. As it is, 
patches 4-7 here just appear to be moving an option around for no 
practical effect.

Robin.

> To achieve that I decided to reuse dma_default_coherent to set default coherency for devicetree.
> And all later patches are severing for this purpose.
> 
> Thanks
> - Jiaxun