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References: <20220629215944.397952-1-heiko@sntech.de> <20220629215944.397952-2-heiko@sntech.de>
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From:   Rob Herring <robh+dt@kernel.org>
Date:   Thu, 30 Jun 2022 08:57:55 -0600
Message-ID: <CAL_JsqJEPL1Jc8k5W4P8hgGzOXxgfqNKNqYuc0nLkCnV274TxA@mail.gmail.com>
Subject: Re: [PATCH v5 1/4] of: also handle dma-noncoherent in of_dma_is_coherent()
To:     Heiko Stuebner <heiko@sntech.de>
Cc:     Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        linux-riscv <linux-riscv@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        wefu@redhat.com, Guo Ren <guoren@kernel.org>, cmuellner@linux.com,
        Philipp Tomsich <philipp.tomsich@vrull.eu>,
        Christoph Hellwig <hch@lst.de>,
        Samuel Holland <samuel@sholland.org>,
        Atish Patra <atishp@atishpatra.org>,
        Anup Patel <anup@brainfault.org>,
        Nick Kossifidis <mick@ics.forth.gr>,
        Krzysztof Kozlowski <krzk+dt@kernel.org>,
        devicetree@vger.kernel.org, Drew Fustini <drew@beagleboard.org>,
        Randy Dunlap <rdunlap@infradead.org>
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On Wed, Jun 29, 2022 at 4:00 PM Heiko Stuebner <heiko@sntech.de> wrote:
>
> of_dma_is_coherent() currently expects the architecture to be
> non-coherent and some devices being coherent getting marked
> as such with the dma-coherent devicetree property.
>
> For PowerPC CONFIG_OF_DMA_DEFAULT_COHERENT was added which currently
> makes of_dma_is_coherent() always return true but doesn't handle
> the case of the architecture being coherent but some devices not.
>
> So modify the function to also check for dma-noncoherent and
> set a suitable default return value. If CONFIG_OF_DMA_DEFAULT_COHERENT
> is set the value starts with true and finding dma-noncoherent will
> set it to false and without CONFIG_OF_DMA_DEFAULT_COHERENT, the
> behaviour is reversed.
>
> Signed-off-by: Heiko Stuebner <heiko@sntech.de>
> ---
>  drivers/of/address.c | 17 ++++++++++-------
>  1 file changed, 10 insertions(+), 7 deletions(-)

Reviewed-by: Rob Herring <robh@kernel.org>