Hello raw NAND fans, today I thought it would be interesting to have all that automatic NAND flash timings setting usable with an old board featuring a at91sam9g20 SoC, which would pave the way to get rid of the old atmel raw nand driver eventually. My "let's try this quickly" ended up in "damn this took hours and now I'm stuck".
Those older SoCs have no hardware ecc engine like the sama5d2 or sam9x60 have, which the Linux driver can work with. (The U-Boot driver was ported from Linux back then.) The problem is NAND flash detection fails because the atmel nand controller drivers fails on probing. In fact `atmel_nand_controller_init()` tries to set the pointer `nc->pmecc` by calling `devm_atmel_pmecc_get()`. That one probably gets a -EPROBE_DEFER returned by `atmel_pmecc_get_by_node()` and then `atmel_nand_controller_init()` returns -EPROBE_DEFER too and probing the driver fails. I suspect it should work fine if `nc->pmecc` would be NULL, but I have no idea what would be the right place to implement this. I also suspect that -EPROBE_DEFER contradicts the U-Boot driver model somehow? The raw/atmel/nand-controller driver was adapted (quite a bit) to work with U-Boot, but maybe some aspects of U-Boot driver model where not considered correctly? The attached patches are what I have so far, marked them as RFC because my actual goal of using the new dm based driver for the old SoC was not completed. Greets Alex P.S.: Patch stack based on next. Alexander Dahl (3): ARM: dts: at91sam9260: Add modern NAND controller nodes memory: atmel-ebi: Add compatible for older 9260 cores mtd: nand: raw: atmel: Remove redundant PMECC probe arch/arm/dts/at91sam9260.dtsi | 47 ++++++++++++++++++++ drivers/memory/atmel_ebi.c | 1 + drivers/mtd/nand/raw/atmel/nand-controller.c | 7 --- drivers/mtd/nand/raw/atmel/pmecc.c | 1 + 4 files changed, 49 insertions(+), 7 deletions(-) base-commit: beedf675b36841ce1e077779157a87a6505317e6 -- 2.39.2
