Kernel 5.10-rc1 not mounting NAND flash (Bisected to d7157ff49a5b ("mtd: rawnand: Use the ECC framework user input parsing bits"))

[Christophe Leroy]

Hi Miquel,

I'm unable to boot 5.10-rc1 on my boards. I get the following error:

[    4.125811] nand: device found, Manufacturer ID: 0xad, Chip ID: 0x76
[    4.131992] nand: Hynix NAND 64MiB 3,3V 8-bit
[    4.136173] nand: 64 MiB, SLC, erase size: 16 KiB, page size: 512,  
OOB size: 16
[    4.143534] ------------[ cut here ]------------
[    4.147934] Unsupported ECC algorithm!
[    4.152142] WARNING: CPU: 0 PID: 1 at  
drivers/mtd/nand/raw/nand_base.c:5244 nand_scan_with_ids+0x1260/0x1640
...
[    4.332052] ---[ end trace e3a36f62cae4ac56 ]---
[    4.336882] gpio-nand: probe of c0000000.nand failed with error -22

Bisected to commit d7157ff49a5b ("mtd: rawnand: Use the ECC framework  
user input parsing bits")

My first impression is that with that change, the value set in chip->ecc.algo
by gpio_nand_probe() in drivers/mtd/nand/raw/gpio.c gets overwritten  
in rawnand_dt_init()

The following change fixes the problem, though I'm not sure it is the  
right fix. Can you have a look ?

diff --git a/drivers/mtd/nand/raw/nand_base.c  
b/drivers/mtd/nand/raw/nand_base.c
index 1f0d542d5923..aa74797cf2da 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -5032,7 +5032,8 @@ static int rawnand_dt_init(struct nand_chip *chip)
  		chip->ecc.engine_type = nand->ecc.defaults.engine_type;

  	chip->ecc.placement = nand->ecc.user_conf.placement;
-	chip->ecc.algo = nand->ecc.user_conf.algo;
+	if (chip->ecc.algo == NAND_ECC_ALGO_UNKNOWN)
+		chip->ecc.algo = nand->ecc.user_conf.algo;
  	chip->ecc.strength = nand->ecc.user_conf.strength;
  	chip->ecc.size = nand->ecc.user_conf.step_size;

---

Thanks
Christophe