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DM816x NAND ECC mode selection

Bandeg
Expert 1140 points

From the following information, TI recommends that we use 8-bit BCH when writing U-BOOT to nand.

http://processors.wiki.ti.com/index.php/DM816x_AM389x_PSP_U-Boot#Flashing_U-Boot_from_U-Boot

http://processors.wiki.ti.com/index.php/DM816x_AM389x_PSP_Flashing_Tools_Guide#Burning_images_to_NAND_Flash_.28using_CCS.29

We would like to boot a kernel that was written to NAND using the Linux mtd-utils program "nandwrite".   When we do this we are getting ECC errors when reading the kernel from u-boot.

Questions:

1) How do we configure Linux to use a desired ECC mode?

2) Do U-BOOT and the DM816x support booting U-boot and a kernel using other ECC modes than HW 8-bit BCH?

Thanks,

--B

  • 0
    TI__Intellectual 1265 points

    Bandeg,

    The Uboot should be flashed to NAND using 8bit BCH because the ROM code reads it using that scheme. The kernel can be flashed in 1 bit HW as well as 8 bit BCH scheme (depending on what scheme the Uboot is reading the flashed kernel). By default the Uboot reads in 1bit HW ECC scheme. So by default, the kernel should be flashed with 1 bit HW ECC scheme.

    1)The ECC mode that Linux would support (read/write) can be altered by changing the ECC scheme mentioned in the following 2 places in the code:

    - kernel/arch/arm/mach-omap2/board-flash.c

    (board_nand_init function - "board_nand_data.ecc_opt = OMAP_ECC_HAMMING_CODE_HW;")

    -kernel/drivers/mtd/nand/omap2.c

    (probe function - "pdata->ecc_opt = OMAP_ECC_HAMMING_CODE_HW;")

    2)The Uboot HAS to be flashed in 8bit BCH mode (as the ROM code reads only using that scheme). The Uboot and linux can support 1bit HW ECC by default.

    Regards,

    Parth