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eMMC boot (boot partition)

Marvin Liang
Expert 3015 points

Other Parts Discussed in Thread: CSD

Hi,

    Anyone tried eMMC boot(boot partition/sysboot[3:0] 0b1011) on J6 EVM?  Development guid only give the guide for the eMMC boot/sysboot[3:0] 0b1000.

   Do we have a description how to test eMMC boot(boot part) on J6 EVM?

Best Regards.

   Marvin

  • 0
    TI__Expert 7885 points

    Marvin

    Please provide  release version details ?

    Please refer to  

    Regards

    Ravi

  • 0 in reply to Ravi B
    TI__Expert 4230 points

    Hi Marvin,

    Yes, I have tried it on DRA7x ES 2.0 Rev H EVM.

    Using eMMC Boot partition for boot is called Alternative Boot mode.

    Even when you use eMMC boot mode ROM code first tries Alternative Boot Mode and then switches to booting from User data area.

    You may find the detailed instructions in TRM 32.3.7.6.2.4 eMMC Partitions Handling in Alternative Boot Operation Mode and 32.3.7.6.2.4.1 eMMC Devices Preflashing

    One needs to set a few bits in the EXT_CSD register such as BOOT_ACK, BOOT_PART_ENABLE, RST_n etc., to ensure boot from boot partition. Details of the bits to be configured given in 32.3.7.6.2.4.1

    You can set these bits from u-boot prompt using "mmc" command or from kernel using "mmc-utils" 

    I would recommend using mmc-utils because you read back ext_csd and see the changes

    mmc-utils can be downloaded from "http://git.kernel.org/cgit/linux/kernel/git/cjb/mmc-utils.git"

     

    To flash the MLO to boot partition, in kernel,

    1. first enable write access

    To enable write access to /dev/mmcblkXbootY, disable the forced read-only
access with:

echo 0 > /sys/block/mmcblkXbootY/force_ro

    for ex,if using boot0
    echo 0 > /sys/block/mmcblk1boot0/force_ro

    2.  Flash MLO
    dd if=MLO of=/dev/mmcblk1boot0 bs=1K

    Change the sysboot to eMMC Boot or eMMC(Boot) and reboot system

    Regards,

    RK

    https://e2e.ti.com/support/arm/automotive_processors/f/1020