VIM1S SDK for DDR3 Hardware

ysn_yaga · November 7, 2024, 5:03am

Hi Team,

I have used VIM1S (S905Y4) schematics to create the custom board with DDR3 instead of DDR4.

I need your help to understand the required boot loader and kernel changes to change from DDR4 to DDR3.

Kindly Advice ?

Regards,
Stalin

numbqq · November 8, 2024, 6:41am

Hello @ysn_yaga

We don’t suggest you to change the DDR type, it need well tuning and we can’t provide the support of this part.

We never tested DDR4, but you can try this way:

Copy this timing to VIM1S timing
Uncomment this line to enable DDR3 timing

github.com

khadas/u-boot/blob/khadas-vims-v2019.01/board/amlogic/s4_ap222/firmware/timing.c#L108


      
          //#define S4_LPDDR4_DONGLE_LAYER_4 1   //use for 1rank lpddr4
          //#define S4_LPDDR4_DONGLE_LAYER_6 1  //use for 1rank lpddr4
          
          #define S4_LPDDR4_2RANK 1
          #define S4_LPDDR4_2RANK_RAYSON_2GB 1
          //#define S4_LPDDR4_2RANK_FORESEE_2GB 1
          
          #define S4_DDR4_2RANK 1
          //#define S4_DDR4_1RANK 1
          //#define S4_DDR4_1RANK_PCB_MODE2_GANGZHENG 1
          //#define S4_DDR3  1
          
          ddr_set_ps0_only_t __ddr_setting[] __attribute__ ((section(".ddr_param"))) = {
          #if S4_DDR3
          	{
          		//timing_config,s4 ddr3
          		.cfg_board_common_setting.timming_magic = 0,
          		.cfg_board_common_setting.timming_max_valid_configs =
          			sizeof(__ddr_setting[0]) / sizeof(ddr_set_ps0_only_t),
          		.cfg_board_common_setting.timming_struct_version = 0,
          		.cfg_board_common_setting.timming_struct_org_size = sizeof(ddr_set_ps0_only_t),

ysn_yaga · November 8, 2024, 7:22am

Hi @numbqq

Is there any dependency on CONFIG_DDRFW_TYPE flag ?
Does linux kernel detect DDR3 / DDR4 automatically or need to change the kernel source as well ?
Regards,
Stalin