emmc 4.4/4.5 device tree

[niklasmolin]

Hi.

I have an emmc with version 4.4/4.5 on my board.

How can I change the dts file to support the higher rate (I assume it just uses the "normal" rate if I don't tell it to use a higher rate or DDR)?

Or is this something I need to change in the code instead?

Also is it possible to boot this device from the i.MX6, since it's using version emmc 4.5 (what is the difference between 4,4 and 4.5 when it comes to boot)  ?

When I populate the image in my flash, what is the best way?

Right now I tried to use the .sdcard file with dd, or do I need to do it in a different way?

Thanks,

Niklas

[igorpadykov]

Hi, Niklas,

from i.MX6Q and i.MX6DL RM:

only support eMMC4.4.1, not support 4.5.

Differencies are significant, you can read them in emmc specs documents.

However BSP supports basic read/write from eMMC 4.5 bypassing eMMC version checking,

so that eMMC v4.5 can work on current kernel as eMMC v4.4 cards, no specific v4.5 feature supported.

ENGR00234519 mmc: support eMMC v4.5 memory cards · 1aa1446 · u-mobo/linux-imx · GitHub

Higher rate or DDR are supported by driver automatically reading eMMC CSD register,

no need for additional configurations.

Populating image to flash is described in i.MX_6Dual6Quad_SABRE-SD_Linux_User's_Guide.pdf

document.

L3.0.35_4.1.0_LINUX_DOCS

i.MX6Q: i.MX 6Quad Family of Applications Processors

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