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if using AM335xBZCZ80 on Linux _SDK_05.06.00.00, what change is needed

Jason Z
Intellectual 560 points

Hi,

I am using  U_BOOT and Linux  based on the Linux_SDK_05.06.00.00 for my project which is using AM335xZCZ72,due to AM335xBZCZ80 is much easier for purchasing and also  many bugs existed before are fixed on B version,I want to using AM335xBZCZ80 to replace the AM335xZCZ72,Can you advice what modification is needed for Linux kernel and u-boot from Linux_SDK_05.06.00.00 ?

 

Cheers,

Jason

  • 0
    TI__Mastermind 25235 points

    Hi,

    Please take a look at this function, located in <u-boot_source_folder>/board/ti/am335x/board.c:

    void am33xx_spl_board_init(void)
    {
        int mpu_vdd, mpu_pll, sil_rev;

        /* Assume PG 1.0 */
        mpu_pll = MPUPLL_M_720;

        sil_rev = readl(&cdev->deviceid) >> 28;
        if (sil_rev == 1)
            /* PG 2.0, efuse may not be set. */
            mpu_pll = MPUPLL_M_800;
        else if (sil_rev >= 2) {
            /* Check what the efuse says our max speed is. */
            int efuse_arm_mpu_max_freq;
            efuse_arm_mpu_max_freq = readl(&cdev->efuse_sma);
            if ((efuse_arm_mpu_max_freq & DEVICE_ID_MASK) ==
                    AM335X_ZCZ_1000)
                mpu_pll = MPUPLL_M_1000;
            else if ((efuse_arm_mpu_max_freq & DEVICE_ID_MASK) ==
                    AM335X_ZCZ_800)
                mpu_pll = MPUPLL_M_800;
        }

    This is copied from the U-Boot source from TI SDK version 06.00.00.00. Please check if it is the same in your version of the SDK. Basically it sets the mpu_pll variable to represent the maximum allowed processor frequency based on the reading of an efuse. If this is not properly detected, the mpu_pll variable is set to 800MHz.

    Best regards,
    Miroslav