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

[Christophe Leroy]

Quoting Miquel Raynal <miquel.raynal at bootlin.com>:

> Hi Christophe,
>
> Christophe Leroy <christophe.leroy at csgroup.eu> wrote on Wed, 4 Nov 2020
> 19:37:57 +0100:
>
>> Hi Miquel,
>>
>> Le 04/11/2020 à 18:38, Miquel Raynal a écrit :
>> > Hi Christophe,
>> >
>> > Christophe Leroy <christophe.leroy at csgroup.eu> wrote on Wed, 04 Nov
>> > 2020 18:33:53 +0100:
>> >
>> >> 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
>> >
>> > Sorry for introducing this issue, I didn't had the time to send the
>> > Fixes PR yet but I think this issue has been solved already. Could
>> > you please try with a recent linux-next?
>> >
>>
>> Sorry, same problem with "Linux version 5.10.0-rc2-next-20201104"
>
> Can you please give this patch a try, please?
>
> ---8<---
>
> Author: Miquel Raynal <miquel.raynal at bootlin.com>
> Date:   Thu Nov 5 08:44:48 2020 +0100
>
>     mtd: rawnand: gpio: Move the ECC initialization to ->attach_chip()
>
>     While forcing a Hamming software ECC looks clearly wrong, let's just
>     fix the situation for now and move these lines to the ->attach_chip()
>     hook which gets executed after the user input parsing and NAND chip
>     discovery.
>
>     Fixes: d7157ff49a5b ("mtd: rawnand: Use the ECC framework user  
> input parsing bits")
>     Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
>
> diff --git a/drivers/mtd/nand/raw/gpio.c b/drivers/mtd/nand/raw/gpio.c
> index 3bd847ccc3f3..6feab847f5e0 100644
> --- a/drivers/mtd/nand/raw/gpio.c
> +++ b/drivers/mtd/nand/raw/gpio.c
> @@ -161,8 +161,15 @@ static int gpio_nand_exec_op(struct nand_chip *chip,
>         return ret;
>  }
>
> +static int gpio_nand_attach_chip(struct nand_chip *chip)
> +{
> +       chip->ecc.mode = NAND_ECC_SOFT;
> +       chip->ecc.algo = NAND_ECC_HAMMING;
> +}
> +
>  static const struct nand_controller_ops gpio_nand_ops = {
>         .exec_op = gpio_nand_exec_op,
> +       .attach_chip = gpio_nand_attach_chip,
>  };
>
>  #ifdef CONFIG_OF
> @@ -342,8 +349,6 @@ static int gpio_nand_probe(struct platform_device *pdev)
>         gpiomtd->base.ops = &gpio_nand_ops;
>
>         nand_set_flash_node(chip, pdev->dev.of_node);
> -       chip->ecc.mode          = NAND_ECC_SOFT;
> -       chip->ecc.algo          = NAND_ECC_HAMMING;
>         chip->options           = gpiomtd->plat.options;
>         chip->controller        = &gpiomtd->base;


Works with the following:

diff --git a/drivers/mtd/nand/raw/gpio.c b/drivers/mtd/nand/raw/gpio.c
index 4ec0a1e10867..66d3f1eb788c 100644
--- a/drivers/mtd/nand/raw/gpio.c
+++ b/drivers/mtd/nand/raw/gpio.c
@@ -161,8 +161,17 @@ static int gpio_nand_exec_op(struct nand_chip *chip,
  	return ret;
  }

+static int gpio_nand_attach_chip(struct nand_chip *chip)
+{
+	chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_SOFT;
+	chip->ecc.algo		= NAND_ECC_ALGO_HAMMING;
+
+	return 0;
+}
+
  static const struct nand_controller_ops gpio_nand_ops = {
  	.exec_op = gpio_nand_exec_op,
+	.attach_chip = gpio_nand_attach_chip,
  };

  #ifdef CONFIG_OF
@@ -342,8 +351,6 @@ static int gpio_nand_probe(struct platform_device *pdev)
  	gpiomtd->base.ops = &gpio_nand_ops;

  	nand_set_flash_node(chip, pdev->dev.of_node);
-	chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_SOFT;
-	chip->ecc.algo		= NAND_ECC_ALGO_HAMMING;
  	chip->options		= gpiomtd->plat.options;
  	chip->controller	= &gpiomtd->base;

---
Christophe