Checking ECC operation

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This page documents the procedure to check whether Error Correction (1 bit or 4 bit) is working correctly from UBL or not on DM365 platform. This has been tested using PSP release 03.21.00.04 which can be downloaded from http://software-dl.ti.com/dsps/dsps_public_sw/psp/LinuxPSP/DaVinci_03_21/03_21_00_04/index_FDS.html.

• Flash the prebuilt UBL (DaVinci-PSP-SDK-03.21.00.04/images/boot-strap/serial_flash/dm36x/ubl_DM36x_ARM297_DDR243_OSC24_NAND.bin) and U-Boot (DaVinci-PSP-SDK-03.21.00.04/images/u-boot/dm36x/u-boot.bin) images onto NAND flash either using serial flash writer or CCS.
• When CCS is used for flashing, U-Boot image gets flashed at NAND offset 0x320000.
• Modify the DM365 board file arch/arm/mach-davinci/board-dm365-evm.c file under the DaVinci-PSP-SDK-03.21.00.04/src/kernel/linux-03.21.00.04 and make the first NAND partition as read/write.
• Build Linux kernel and boot the EVM with this kernel image.
• From Linux prompt, read the U-Boot contents and store in a file.

target$ nanddump -f correct_dump -l 0x60000 -s 0x320000 /dev/mtd0

• Edit the file and introduce a 1 bit error at some offset and save the modified file.
• Erase the blocks in which U-Boot is stored.

target$ flash_erase /dev/mtd0 0x320000 3

• Write back the data which has the incorrect data:

target$ nandwrite -n -o -s 0x320000 /dev/mtd0 incorrect_dump
Where:
-n, --noecc             Write without ecc
-o, --oob               Image contains oob data

• Reboot the EVM. If UBL is able to correct the data, then U-Boot should boot up without any problem.