TDA4VL-Q1: MMCSD driver: set pSLC mode for eMMC

Hi Andreas,

Andreas K said:

Is there any way to enable pSLC mode for the eMMC using the MMCSD driver?

Currently,it is not present in the MMCSD driver . Since this option is only one-time configurable,it is better to rather configure it from either UBOOT or linux kernel.

Andreas K said:

If not, which eMMC command can I use to write certain values of the ECSD register? Do you have any example of pSLC mode activation via SBL?

Configuring PSLC in Linux kernel using mmc-util:

Command : [mmc enh_area --help] command in the userspace of linux kernel.

Configuring PSLC in UBOOT:

1:Enter into Linux kernel,execute the following command ,and just note it down:

   > cat /sys/class/block/mmcblk0/size

   It basically indicates the number of 512 blocks present in the emmc uda partition

2:Reboot into Uboot and enter the below command which will just test if it is working:

> mmc hwpartition user enh <start> <number of 512B sized blocks> check

SYNTAX:



I am attaching an example below just for reference:

Here 62160896 is the value obtained after running cat /sys/class/block/mmcblk0/size as stated earlier.

Here 1264 indicates the maximum number of HC WP Group Size(8Mib(as in the below image)) blocks allowed.

Hence number of 512B sized blocks now = (1264×8×1024×1024)/512 which is equal to 20709376 which works fine.


3:Now to set this configuration permanently:

NOTE:Because all the operations are one-time only,be very careful before applying the below command.

 > mmc hwpartition user enh 0 20709376 wrrel on complete

4:Power cycle the board for the changes to get applied.

Hi Gokul,

I was able to perform this change manually in the SBL by utilizing the MMCSD_v2_transfer() function.

One last question for this topic: Do you have an idea how long it takes the eMMC to apply these changes after a powercycle? Does the SBL wait for finalization of the pSLC mode when initializing the eMMC with MMCSD_init()?

best regards,

Andreas