2022-06-14 14:17:10

by Ariel D'Alessandro

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Subject: [PATCH] ARM: dts: bcm2711-rpi: Use aliases to set custom MMC device index

Add MMC aliases to ensure that the /dev/mmcblk ID for the first
eMMC/SD card won't change depending on the probe order of the MMC
drivers.

Signed-off-by: Ariel D'Alessandro <[email protected]>
---

Changes in v2:
* Moved alias from bcm2711-rpi-4-b.dts to bcm2711-rpi.dtsi

arch/arm/boot/dts/bcm2711-rpi.dtsi | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/arm/boot/dts/bcm2711-rpi.dtsi b/arch/arm/boot/dts/bcm2711-rpi.dtsi
index ca266c5d9f9b..a39b2f68e4cc 100644
--- a/arch/arm/boot/dts/bcm2711-rpi.dtsi
+++ b/arch/arm/boot/dts/bcm2711-rpi.dtsi
@@ -13,6 +13,7 @@ memory@0 {
aliases {
emmc2bus = &emmc2bus;
ethernet0 = &genet;
+ mmc0 = &emmc2; /* mmcblk0 for eMMC/SD */
pcie0 = &pcie0;
blconfig = &blconfig;
};
--
2.34.1


2022-06-14 21:55:58

by Stefan Wahren

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Subject: Re: [PATCH] ARM: dts: bcm2711-rpi: Use aliases to set custom MMC device index

Hi Ariel,

Am 14.06.22 um 16:12 schrieb Ariel D'Alessandro:
> Add MMC aliases to ensure that the /dev/mmcblk ID for the first
> eMMC/SD card won't change depending on the probe order of the MMC
> drivers.

this changes the emmc2 from mmc1 to mmc0 in my case (RPi 4,
multi_v7_defconfig), which i consider as a regression / unexpected
change in userspace.

Could you please explain your actual motivation of your patch?

>
> Signed-off-by: Ariel D'Alessandro <[email protected]>
> ---
>
> Changes in v2:
> * Moved alias from bcm2711-rpi-4-b.dts to bcm2711-rpi.dtsi
>
> arch/arm/boot/dts/bcm2711-rpi.dtsi | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/arm/boot/dts/bcm2711-rpi.dtsi b/arch/arm/boot/dts/bcm2711-rpi.dtsi
> index ca266c5d9f9b..a39b2f68e4cc 100644
> --- a/arch/arm/boot/dts/bcm2711-rpi.dtsi
> +++ b/arch/arm/boot/dts/bcm2711-rpi.dtsi
> @@ -13,6 +13,7 @@ memory@0 {
> aliases {
> emmc2bus = &emmc2bus;
> ethernet0 = &genet;
> + mmc0 = &emmc2; /* mmcblk0 for eMMC/SD */
> pcie0 = &pcie0;
> blconfig = &blconfig;
> };

2022-06-29 18:46:12

by Ariel D'Alessandro

[permalink] [raw]
Subject: Re: [PATCH] ARM: dts: bcm2711-rpi: Use aliases to set custom MMC device index

Hi Stefan,

Sorry for the delay.

On 6/14/22 17:47, Stefan Wahren wrote:
> Hi Ariel,
>
> Am 14.06.22 um 16:12 schrieb Ariel D'Alessandro:
>> Add MMC aliases to ensure that the /dev/mmcblk ID for the first
>> eMMC/SD card won't change depending on the probe order of the MMC
>> drivers.
>
> this changes the emmc2 from mmc1 to mmc0 in my case (RPi 4,
> multi_v7_defconfig), which i consider as a regression / unexpected
> change in userspace.
>
> Could you please explain your actual motivation of your patch?

That's a good point. The original reason comes from u-boot in fact, I
just sent the patch here as u-boot is syncing the dts files from the kernel.

U-boot uses the same defconfig `configs/rpi_arm64_defconfig` for
different RPi versions, which have different mmcblk ids numbering.

In order to use bootcount support in u-boot, the config option
CONFIG_SYS_BOOTCOUNT_EXT_DEVPART needs to be filled with the fixed
dev/part ids. In general I'd expect mmcblk0 to be eMMC/SD, which is not
in this case, at least for RPi4.

Anyway, this is probably something to be discussed on the u-boot mailing
list, not here.

Thanks,
Ariel

>
>>
>> Signed-off-by: Ariel D'Alessandro <[email protected]>
>> ---
>>
>> Changes in v2:
>> * Moved alias from bcm2711-rpi-4-b.dts to bcm2711-rpi.dtsi
>>
>>   arch/arm/boot/dts/bcm2711-rpi.dtsi | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/arm/boot/dts/bcm2711-rpi.dtsi
>> b/arch/arm/boot/dts/bcm2711-rpi.dtsi
>> index ca266c5d9f9b..a39b2f68e4cc 100644
>> --- a/arch/arm/boot/dts/bcm2711-rpi.dtsi
>> +++ b/arch/arm/boot/dts/bcm2711-rpi.dtsi
>> @@ -13,6 +13,7 @@ memory@0 {
>>       aliases {
>>           emmc2bus = &emmc2bus;
>>           ethernet0 = &genet;
>> +        mmc0 = &emmc2;    /* mmcblk0 for eMMC/SD */
>>           pcie0 = &pcie0;
>>           blconfig = &blconfig;
>>       };