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Subject: Re: [PATCH 1/3] dt-bindings: mmc: meson-gx: add ddr-access-quirk
 property
To:     Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc:     ulf.hansson@linaro.org, khilman@baylibre.com,
        devicetree@vger.kernel.org, baylibre-upstreaming@groups.io,
        linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-amlogic@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org
References: <20190513091548.16674-1-narmstrong@baylibre.com>
 <20190513091548.16674-2-narmstrong@baylibre.com>
 <CAFBinCAhTeywLZRBhcX_myktU9k4_YcjsjgCeTHEkP7SX8JCMQ@mail.gmail.com>
From:   Neil Armstrong <narmstrong@baylibre.com>
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Organization: Baylibre
Message-ID: <9615cdb8-0a7e-fd39-45f0-79fdc7c0441c@baylibre.com>
Date:   Wed, 15 May 2019 14:43:31 +0200
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On 14/05/2019 19:50, Martin Blumenstingl wrote:
> Hi Neil,
> 
> On Mon, May 13, 2019 at 11:16 AM Neil Armstrong <narmstrong@baylibre.com> wrote:
>>
>> On the Amlogic G12A SoC family, (only) the SDIO controller has a bug which
>> makes any DDR access from the MMC controller fail.
>>
>> Add the amlogic,ddr-access-quirk property so signal this particular
>> controller has this bug and needs a quirk to work properly.
>>
>> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
> Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> 
>> ---
>>  Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt b/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
>> index 13e70409e8ac..f8914dab06c6 100644
>> --- a/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
>> +++ b/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
>> @@ -22,6 +22,10 @@ Required properties:
>>    clock rate requested by the MMC core.
>>  - resets     : phandle of the internal reset line
>>
>> +Optional properties:
>> +- amlogic,ddr-access-quirk: set when HW cannot access the DDR memory, like on
>> +  the G12A SDIO controller.
> (I believe we cannot use a standard property like "dma-ranges" to
> disable DMA access)
> personally I prefer "amlogic,no-direct-memory-access" or
> "amlogic,no-ddr-access", but if Rob is happy with the current naming
> then I'm happy as well

I have no preference, I can change it easily,

Neil

> 
> 
> Regards
> Martin
>