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Subject: Re: [PATCH V4 1/3] mmc: sdhci: add support for using external DMA
 devices
To:     Chunyan Zhang <zhang.chunyan@linaro.org>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Faiz Abbas <faiz_abbas@ti.com>
Cc:     linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
        Arnd Bergmann <arnd@arndb.de>, Mark Brown <broonie@kernel.org>,
        Kishon Vijay Abraham I <kishon@ti.com>,
        Sekhar Nori <nsekhar@ti.com>,
        Chunyan Zhang <zhang.lyra@gmail.com>
References: <1544519572-21921-1-git-send-email-zhang.chunyan@linaro.org>
 <1544519572-21921-2-git-send-email-zhang.chunyan@linaro.org>
From:   Adrian Hunter <adrian.hunter@intel.com>
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Date:   Thu, 27 Dec 2018 09:42:56 +0200
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On 11/12/18 11:12 AM, Chunyan Zhang wrote:
> Some standard SD host controllers can support both external dma
> controllers as well as ADMA/SDMA in which the SD host controller
> acts as DMA master. TI's omap controller is the case as an example.
> 
> Currently the generic SDHCI code supports ADMA/SDMA integrated in
> the host controller but does not have any support for external DMA
> controllers implemented using dmaengine, meaning that custom code is
> needed for any systems that use an external DMA controller with SDHCI.
> 
> Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>

FYI, I am waiting on successful testing before reviewing these patches again.