Re: [PATCH 1/3] mtd: rawnand: Add a NAND_NO_BBM_QUIRK flag

[Boris Brezillon <boris.brezillon@collabora.com>]

On Mon, 27 Apr 2020 09:24:51 +0200
Boris Brezillon <boris.brezillon@collabora.com> wrote:

> Some controllers with embedded ECC engines override the BBM marker with
> data or ECC bytes, thus making bad block detection through bad block
> marker impossible. Let's flag those chips so the core knows it shouldn't
> check the BBM and consider all blocks good.
> 
> This should allow us to get rid of two implementers of the
> legacy.block_bad() hook.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> ---
>  drivers/mtd/nand/raw/nand_base.c | 3 +++
>  include/linux/mtd/rawnand.h      | 8 ++++++++
>  2 files changed, 11 insertions(+)
> 
> diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> index f81b54634061..749ef0b40684 100644
> --- a/drivers/mtd/nand/raw/nand_base.c
> +++ b/drivers/mtd/nand/raw/nand_base.c
> @@ -345,6 +345,9 @@ static int nand_block_bad(struct nand_chip *chip, loff_t ofs)
>  
>  static int nand_isbad_bbm(struct nand_chip *chip, loff_t ofs)
>  {
> +	if (chip->options & NAND_NO_BBM_QUIRK)
> +		return 0;
> +
>  	if (chip->legacy.block_bad)
>  		return chip->legacy.block_bad(chip, ofs);
>  
> diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h
> index 99f4ac47c8d3..37613dd9e04b 100644
> --- a/include/linux/mtd/rawnand.h
> +++ b/include/linux/mtd/rawnand.h
> @@ -222,6 +222,14 @@ enum nand_ecc_algo {
>   */
>  #define NAND_KEEP_TIMINGS	0x00800000
>  
> +/*
> + * Some controllers with pipelined ECC engines override the BBM marker with
> + * data or ECC bytes, thus making bad block detection through bad block marker
> + * impossible. Let's flag those chips so the core knows it shouldn't check the
> + * BBM and consider all blocks good.
> + */
> +#define NAND_NO_BBM_QUIRK	0

Oops, should be 

#define NAND_NO_BBM_QUIRK	0x08000000

I'll have to rebase it on Miquel's series re-ordering the flag
definitions and using the BIT() macro anyway. But please don't take this
as an excuse for not reviewing this version :P.

> +
>  /* Cell info constants */
>  #define NAND_CI_CHIPNR_MSK	0x03
>  #define NAND_CI_CELLTYPE_MSK	0x0C


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