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

From: Miquel Raynal <[email-masked]>
Date: Thu, 5 Nov 2020 10:13:19 +0100

Hi Christophe,

Christophe Leroy <[email-masked]> wrote on Thu, 05 Nov
2020 10:06:51 +0100:

> Quoting Miquel Raynal <[email-masked]>:
> 
> > Hi Christophe,
> >
> > Christophe Leroy <[email-masked]> 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 <[email-masked]> 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: 0x  
> 76
> >> >> [    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 -2  
> 2
> >> >>
> >> >> 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 *ch  
> ip)
> >> >>    		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 <[email-masked]>
> > 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 <[email-masked]>
> >
> > 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 *pd  
> ev)
> >         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;
> +}

Yup indeed it was not even compile tested. Good to know, I'll check
the other drivers and send the patch soon.

Thanks,
Miquèl