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Subject: Re: [PATCH v2 0/3] Add support for using external dma in SDHCI
From:   "Rizvi, Mohammad Faiz Abbas" <faiz_abbas@ti.com>
To:     Chunyan Zhang <zhang.chunyan@linaro.org>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Adrian Hunter <adrian.hunter@intel.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>, <broonie@kernel.org>
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Message-ID: <5a45f520-03b0-3679-2175-a19681062bf6@ti.com>
Date:   Wed, 28 Nov 2018 22:28:52 +0530
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+ Mark Brown

Chunyan,

On 11/21/2018 5:17 PM, Faiz Abbas wrote:
> Hi Chunyan,
> 
> On 12/11/18 12:56 PM, Chunyan Zhang wrote:
>> Currently the generic SDHCI code in the Linux kernel supports the SD
>> standard DMA integrated into 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 a generic DMA
>> controller with SDHCI which in practice means any SDHCI controller that
>> doesn't have an integrated DMA controller so we should have this as a
>> generic feature.
>>
>> There are already a number of controller specific drivers that have dmaengine
>> code, and some could use sdhci.c actually, but needed to implement mmc_ops->request()
>> in their specific driver for sending command with external dma using dmaengine
>> framework, with this patchset, them will take advantage of the generic support.
>> TI's omap controller is the case as an example.
>>
>> Any comments are very appreciated.
>>
> 
> This is great. It helps us move am335x and am43xx platforms to
> sdhci-omap. What platforms have you tested this on?
> 

Gentle ping on this. I tried testing these with an am335x-evm board. In 
their current condition, the card fails to enumerate altogether. The 
changes suggested by Adrian should fix this. Let me know when you post a v3.

Thanks,
Faiz