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Subject: Re: [PATCH] ARM: dts: exynos: Assign a fixed index to mmc devices on
 ODROID XU3/4 boards
To:     Marek Szyprowski <m.szyprowski@samsung.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzk@kernel.org>
Cc:     devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org
References: <CGME20201104105152eucas1p28eb6ca629a685f24a2463c72898fdbc5@eucas1p2.samsung.com>
 <20201104100855.2337-1-m.reichl@fivetechno.de>
 <4ac01b71-e806-18c8-13ce-6acdcc1a3b41@samsung.com>
From:   Markus Reichl <m.reichl@fivetechno.de>
Organization: five technologies GmbH
Message-ID: <28660119-ffe3-cd01-0daa-8c0994e29571@fivetechno.de>
Date:   Wed, 4 Nov 2020 13:42:17 +0100
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Hi Marek,

Am 04.11.20 um 13:24 schrieb Marek Szyprowski:
> Hi Markus,
> 
> On 04.11.2020 11:08, Markus Reichl wrote:
>> Recently introduced async probe on mmc devices can shuffle block IDs.
>> Pin them to fixed values to ease booting in evironments where UUIDs
>> are not practical. Use newly introduced aliases for mmcblk devices from [1].
>>
>> [1]
>> https://patchwork.kernel.org/patch/11747669/
> 
> Wow, this is a long standing issue, called by others 'a feature'. Good
> that this has been finally solved.
> 
>> Signed-off-by: Markus Reichl <m.reichl@fivetechno.de>
>> ---
>>   arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi | 5 +++++
>>   1 file changed, 5 insertions(+)
>>
>> diff --git a/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi b/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
>> index e35af40a55cb..91d2840ac8ca 100644
>> --- a/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
>> +++ b/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
>> @@ -13,6 +13,11 @@
>>   #include "exynos5422-odroid-core.dtsi"
>>   
>>   / {
>> +	aliases {
>> +		mmc0 = &mmc_2;
>> +		mmc1 = &mmc_0;
> 
> Frankly, I would keep the MMC numbers the same as in u-boot and
> datasheets. 0 for the build-in eMMC and 2 for the SD-card. This would be
> much more natural. On the other hand, I would agree to do it differently
> only on Odroid HC1/HD2/MC1, which don't have build-in eMMC - just use 0
> there for the SD-card.

This would break present and long standing  boot ordering in mainline, which is
mmcblk0 = SD-card and
mmcblk1 = eMMC

Still desired?
> 
>> +	};
>> +
>>   	gpio-keys {
>>   		compatible = "gpio-keys";
>>   		pinctrl-names = "default";
> 
> Best regards
> 

Gruß,
-- 
Markus Reichl