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TDA4VM: We want change the ram size from uboot(device tree)

Part Number: TDA4VM

Hi ,

We want change the ram size from 16G to 8G

device tree 

k3-j721s2-som-p0.dtsi

memory@80000000 {
        device_type = "memory";
        /* 16 GB RAM */
        reg = <0x00 0x80000000 0x00 0x80000000>,
              <0x08 0x80000000 0x03 0x80000000>;
    };
How colud we modify the reg to 8G?
or any other file need to modify ?
 
  • HI,

    There is an FAQ on J721e: https://e2e.ti.com/support/processors/f/791/t/1097117

    Please follow along the similar lines on j721s2.

    - Keerthy

  • I change as follow but still show 16G on uboot
    //Modify b/arch/arm/dts/k3-j721s2-som-p0.dtsi

    memory@80000000 {
            device_type = "memory";
            /* 16 GB RAM */
            reg = <0x00 0x80000000 0x00 0x80000000>,
    #            <0x08 0x80000000 0x03 0x80000000>;
                  <0x08 0x80000000 0x01 0x80000000>;
        };
    //b/arch/arm/mach-k3/arm64-mmu.c //don't know how to modify for block-size (example is 4g to 1g)
    //b/board/ti/j721s2/evm.c  //don't know how to modify for block-size (example is 4g to 1g)
    //b/configs/j721e_evm_a72_defconfig // we are 2 block of 4g , no need to modify to 1
    What should I do next setp or somethings wrong?
  • I find I missed modify evm.c . Thanks for your help

  • Hi Pierre,

    Great! For our reference could you please paste the complete code changes diff here?

    Closing this one.

    - Keerthy

  • Hi Keerthy:

    //b/board/ti/j721s2/evm.c 

    in't dram_init_banksize(void)
    {
        /* Bank 0 declares the memory available in the DDR low region */
        gd->bd->bi_dram[0].start = CONFIG_SYS_SDRAM_BASE;
        gd->bd->bi_dram[0].size = 0x7fffffff; //2g
        gd->ram_size = 0x80000000;

    #ifdef CONFIG_PHYS_64BIT
        /* Bank 1 declares the memory available in the DDR high region */
        gd->bd->bi_dram[1].start = CONFIG_SYS_SDRAM_BASE1;
    //  gd->bd->bi_dram[1].size = 0x37fffffff; // 14g to 6g 
        gd->bd->bi_dram[1].size = 0x17fffffff; // 14g to 6g 
        gd->ram_size = 0x400000000;
    #endif

        return 0;
    }
     
    Thanks for your help.