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From:   Michael Ellerman <mpe@ellerman.id.au>
To:     Ulf Hansson <ulf.hansson@linaro.org>
Cc:     Rob Herring <robh+dt@kernel.org>,
        DTML <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Christoph Hellwig <hch@lst.de>,
        Christian Zigotzky <chzigotzky@xenosoft.de>,
        linuxppc-dev@ozlabs.org
Subject: Re: [PATCH] of: Add OF_DMA_DEFAULT_COHERENT & select it on powerpc
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References: <20200126115247.13402-1-mpe@ellerman.id.au> <CAPDyKFrbYmV6_nV6psVLq6VRKMXf0PXpemBbj48yjOr3P130BA@mail.gmail.com>
Date:   Fri, 31 Jan 2020 21:40:03 +1100
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Ulf Hansson <ulf.hansson@linaro.org> writes:
> On Sun, 26 Jan 2020 at 12:53, Michael Ellerman <mpe@ellerman.id.au> wrote:
>> There's an OF helper called of_dma_is_coherent(), which checks if a
>> device has a "dma-coherent" property to see if the device is coherent
>> for DMA.
>>
>> But on some platforms devices are coherent by default, and on some
>> platforms it's not possible to update existing device trees to add the
>> "dma-coherent" property.
>>
>> So add a Kconfig symbol to allow arch code to tell
>> of_dma_is_coherent() that devices are coherent by default, regardless
>> of the presence of the property.
>>
>> Select that symbol on powerpc when NOT_COHERENT_CACHE is not set, ie.
>> when the system has a coherent cache.
>>
>> Fixes: 92ea637edea3 ("of: introduce of_dma_is_coherent() helper")
>> Cc: stable@vger.kernel.org # v3.16+
>> Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de>
>> Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
>> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
>
> Thanks Michael for helping out fixing and this! The patch looks good to me.
>
> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

Thanks for the review.

cheers