TDA4VM: J721 drive device number

Cherry Zhou

Part Number: TDA4VM

Hi team,

When used emmc for boot flash, the customer found that the emmc mapped device number had both /dev/mmcblk0, /dev/mmcblk1, and they would like the device number to be fixed. How to modify it? Thanks.

Best Regards,

Cherry

over 2 years ago

0 Diwakar Dhyani over 2 years ago

TI__Guru 57065 points

HI Cherry

You can fix the instance number by providing the alias like this

    aliases {
          mmc0 = &main_sdhci0;
          mmc1 = &main_sdhci1;
     };

Regards
Diwakar

0 Cherry Zhou over 2 years ago in reply to Diwakar Dhyani

TI__Mastermind 22235 points

Hi Diwakar,

Thank you for the support.

The customer tried to modify the device tree file and then recompile the Linux kernel without taking effect. The sequence of operation is as follows:

1) Modify SDK-path/board-support/Linux-5.10.162/arch/ARM64/boot/DTS/ti/K3-j721e-common-proc-board.DTS. Add aliases at:

2) Rebuild Linux and copy the Image and DTB files under the generated boot folder to the root FS partition boot folder under EMMC.

3) Multiple reboots, with only one MMC device (only EMMC without SD card), the /dev/mmcblk1 condition still occurs:

Thanks and regards,

Cherry

0 Diwakar Dhyani over 2 years ago in reply to Cherry Zhou

TI__Guru 57065 points

HI Cherry

Cherry Zhou said:
3) Multiple reboots, with only one MMC device (only EMMC without SD card), the /dev/mmcblk1 condition still occurs:

The customer is just using emmc and they dont have SD card ?

They want to make sure that emmc get dev/mmcblk0, am i correct ?

Help share the dtb they are using

Regards
Diwakar

0 Cherry Zhou over 2 years ago in reply to Diwakar Dhyani

TI__Mastermind 22235 points

Hi Diwakar,

Diwakar Dhyani said:
The customer is just using emmc and they dont have SD card ?

They want to make sure that emmc get dev/mmcblk0, am i correct ?

Yes, they are testing on the evaluation board with the goal of removing the SD card, using only EMMC, and fixing the device number of the EMMC to /dev/mmcblk0. The DTS file and the DTB file are as follows:

https://e2echina.ti.com/cfs-file/__key/communityserver-discussions-components-files/120/k3_2D00_j721e.rar

Thanks and regards,

Cherry

0 Diwakar Dhyani over 2 years ago in reply to Cherry Zhou

TI__Guru 57065 points

Hi Cherry

If they are not using sd card they can remove the sd node (main_sdhci1) from the both k3-j721e-main.dtsi and k3-j721e-common-proc-board.dt device tree.

also remove alias for mmc1 = &main_sdhci1;

Regards
Diwakar

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TDA4VM: J721 drive device number