LPDDR4x configuration

VIM4
1

Which system do you use? Android, Ubuntu, OOWOW or others?

Ubuntu 22.04 gnome version

Which version of system do you use? Khadas official images, self built images, or others?

Khadas official image

Please describe your issue below:

I’m studying u-boot.
There is a part in the [ timing.c ] file to set the DDR as follows:
…
.DramType = CONFIG_DDR_TYPE_LPDDR4,
.enable_lpddr4x_mode = ENABLE_LPDDR4X_MODE,
.DRAMFreq ={ 2016, 0, 0, 0 },
.ddr_rfc_type = DDR_RFC_TYPE_LPDDR4_8Gbx1,
…

And there is a part in the [ ddr_define.h ] file has a define of ddr_rfc_type as follows:

#define DDR_RFC_TYPE_DDR4_2Gbx1 5
#define DDR_RFC_TYPE_DDR4_2Gbx2 6
#define DDR_RFC_TYPE_DDR4_2Gbx4 7
#define DDR_RFC_TYPE_DDR4_2Gbx8 8

#define DDR_RFC_TYPE_LPDDR4_2Gbx1 9
#define DDR_RFC_TYPE_LPDDR4_3Gbx1 10
#define DDR_RFC_TYPE_LPDDR4_4Gbx1 11
#define DDR_RFC_TYPE_LPDDR4_6Gbx1 12
#define DDR_RFC_TYPE_LPDDR4_8Gbx1 13

Question :

  1. Why do DDR4 define have x1/x2/x4/x8 and LPDDR4 define only have x1 ?
  2. What does x1/x2/x4/x8 mean?
  3. VIM4 is equipped with 32Gb LPDDR4x 2ea, why is it set to LPDDR4_8Gbx1?

Post a console log of your issue below:


**Delete this line and post your log here.**
2

Hello @cuckoo933

There is no documentation about the DDR part, you can do nothing with it, and the DDR is already well trained, you don’t need to change anything.

3

I’m very curious, where can I find out if I want to know?

4

Sorry, we don’t have such documentations.