STM32MP157 FMC Dual Die DTS

[hreysenbach]

Hello,

I am trying to interface the STM32MP157 to a dual die NAND. I have found this previous post: https://community.st.com/t5/stm32-mpus-embedded-software-and/interfacing-fmc-with-multiple-chip-selects-on-a-single-nand/m-p/301979 and I can see Linux correctly detects the NAND:

[ 1.482407] stm32_fmc2_nfc 80000000.nand-controller: nand->ncs = 0x8
[ 1.482447] stm32_fmc2_nfc 80000000.nand-controller: nfc->cs_assigned = 0x3
[ 1.484296] nand: device found, Manufacturer ID: 0x01, Chip ID: 0xd3
[ 1.484322] nand: AMD/Spansion S34ML16G2
[ 1.484332] nand: 2048 MiB, SLC, erase size: 128 KiB, page size: 2048, OOB size: 128
[ 1.484371] nand: 2 chips detected
[ 1.484457] Scanning device for bad blocks

However when I run `ubiformat`, `flash_erase` or `mtdinfo`, the NAND is detected 4GiB instead of 2GiB:

root@device:/root# mtdinfo /dev/mtd13
mtd13
Name:                           80000000.nand-controller
Type:                           nand
Eraseblock size:                131072 bytes, 128.0 KiB
Amount of eraseblocks:          32768 (4294967296 bytes, 4.0 GiB)
Minimum input/output unit size: 2048 bytes
Sub-page size:                  2048 bytes
OOB size:                       128 bytes
Character device major/minor:   90:26
Bad blocks are allowed:         true
Device is writable:             true

Devicetree for reference:

&fmc{
    pinctrl-names = "default", "sleep";
    pinctrl-0 = <&fmc_pins_mx>;
    pinctrl-1 = <&fmc_sleep_pins_mx>;
    status = "disabled";

    /* USER CODE BEGIN fmc */
    nand-controller@4,0 {
        status = "okay";

            nand@0 {
                reg = <0 1>;
                nand-on-flash-bbt;
                nand-ecc-strength = <4>;
                nand-ecc-step-size = <512>;
                #address-cells = <1>;
                #size-cells = <1>;
            };
        };
    /* USER CODE END fmc */
};

This is causing any ubifs operations to fail because it rereads a PEB which contains a duplicated LEB and causes the ubifs operation to fail.
Any advice would be greatly appreciated.

Thanks!