[openwrt/openwrt] qualcommax: ipq50xx: fix NAND ECC for ELECOM WRC-X3000GS2

[LEDE Commits]

robimarko pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/8fb46725cf16bce8a3f17db22b9479a419dae105

commit 8fb46725cf16bce8a3f17db22b9479a419dae105
Author: INAGAKI Hiroshi <musashino.open at gmail.com>
AuthorDate: Sat May 10 16:33:04 2025 +0900

    qualcommax: ipq50xx: fix NAND ECC for ELECOM WRC-X3000GS2
    
    Specify 4-bit ECC strength instead of 8-bit, to resolve NAND I/O errors
    on ELECOM WRC-X3000GS2.
    
    ELECOM WRC-X3000GS2 has a Macronix MX35UF1G24AD SPI-NAND chip as a flash
    storage. That chip is registered as a chip that has 128 bytes OOB and
    requires 8-bit ECC, and described as the same in the Macronix's datasheet.
    
    But on WRC-X3000GS2, 8-bit ECC breaks NAND I/O on mtdblock devices with
    the following errors and 4-bit ECC needs to be used to resolve this issue.
    
    current (ECC strength=8):
    
    ```
    [    1.401566] 0x000000480000-0x000000500000 : "0:appsblenv"
    [    1.407128] 1 fixed-partitions partitions found on MTD device 0:appsblenv
    [    1.410663] Creating 1 MTD partitions on "0:appsblenv":
    [    1.417359] 0x000000000000-0x000000040000 : "env-data"
    [    1.479865] u-boot-env-layout: probe of 79b0000.qpic-nand:flash at 0:partitions:partition-0-appsblenv:partition at 0:nvmem-layout failed with error -74
    
    root at OpenWrt:~# strings /dev/mtdblock10
    [   55.693754] mtdblock: MTD device '0:appsblenv' is NAND, please consider using UBI block devices instead.
    [   55.694660] I/O error, dev mtdblock10, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 4 prio class 2
    [   55.703147] I/O error, dev mtdblock10, sector 8 op 0x0:(READ) flags 0x80700 phys_seg 3 prio class 2
    [   55.711884] I/O error, dev mtdblock10, sector 16 op 0x0:(READ) flags 0x80700 phys_seg 2 prio class 2
    [   55.720778] I/O error, dev mtdblock10, sector 24 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2
    [   55.730310] I/O error, dev mtdblock10, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2
    [   55.738607] Buffer I/O error on dev mtdblock10, logical block 0, async page read
    ```
    
    after fixing (ECC strength=4):
    
    ```
    [    1.402301] 0x000000480000-0x000000500000 : "0:appsblenv"
    [    1.407909] 1 fixed-partitions partitions found on MTD device 0:appsblenv
    [    1.411370] Creating 1 MTD partitions on "0:appsblenv":
    [    1.418075] 0x000000000000-0x000000040000 : "env-data"
    (no error)
    
    root at OpenWrt:~# strings /dev/mtdblock10
    [   39.131008] mtdblock: MTD device '0:appsblenv' is NAND, please consider using UBI block devices instead.
    bootcmd=bootipq
    baudrate=115200
    wifi2=7C:F8:54:01:BD:F3
    CRASH_COUNT=0
    ...
    
    ```
    
    Fixes: 01b72ce61e ("qualcommax: ipq50xx: remove ECC user config from board files")
    Signed-off-by: INAGAKI Hiroshi <musashino.open at gmail.com>
    Link: https://github.com/openwrt/openwrt/pull/18770
    Signed-off-by: Robert Marko <robimarko at gmail.com>
---
 .../files/arch/arm64/boot/dts/qcom/ipq5018-wrc-x3000gs2.dts           | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/target/linux/qualcommax/files/arch/arm64/boot/dts/qcom/ipq5018-wrc-x3000gs2.dts b/target/linux/qualcommax/files/arch/arm64/boot/dts/qcom/ipq5018-wrc-x3000gs2.dts
index 69f124cb9d..fc3e86b870 100644
--- a/target/linux/qualcommax/files/arch/arm64/boot/dts/qcom/ipq5018-wrc-x3000gs2.dts
+++ b/target/linux/qualcommax/files/arch/arm64/boot/dts/qcom/ipq5018-wrc-x3000gs2.dts
@@ -164,6 +164,10 @@
 		#size-cells = <1>;
 
 		nand-ecc-engine = <&qpic_nand>;
+
+		/* strength=8 breaks NAND I/O, use 4 instead */
+		nand-ecc-strength = <4>;
+		nand-ecc-step-size = <512>;
 		nand-bus-width = <8>;
 
 		partitions {