[U-Boot] [PATCH 4/9] imx: nand: Place BBT patterns into free OOB region

[Scott Wood]

On 04/13/2012 06:20 AM, Timo Ketola wrote:
> First two bytes of the first OOB of erase block are reserved for factory
> bad block marking, usually.
> 
> Signed-off-by: Timo Ketola <timo at exertus.fi>
> ---
>  drivers/mtd/nand/mxc_nand.c |   35 +++++++++++++++++++++++++++++++++++
>  1 files changed, 35 insertions(+), 0 deletions(-)

So what happened before?  The default is at offset 8, which doesn't
conflict with the bad block marker.  It seems the actual issue is a
conflict with ECC?

And NAND_USE_FLASH_BBT wasn't defined before, so a better subject line
for this patch would be "nand/mxc: support flash-based BBT".

> diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c
> index 35e89a0..73813a2 100644
> --- a/drivers/mtd/nand/mxc_nand.c
> +++ b/drivers/mtd/nand/mxc_nand.c
> @@ -1302,12 +1302,47 @@ static void mxc_setup_config1(void)
>  #define mxc_setup_config1()
>  #endif
>  
> +#ifdef CONFIG_SYS_NAND_USE_FLASH_BBT
> +
> +static u8 bbt_pattern[] = {'B', 'b', 't', '0' };
> +static u8 mirror_pattern[] = {'1', 't', 'b', 'B' };
> +
> +static struct nand_bbt_descr bbt_main_descr = {
> +	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE |
> +		   NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
> +	.offs =	2,
> +	.len = 4,
> +	.veroffs = 6,
> +	.maxblocks = 4,
> +	.pattern = bbt_pattern,
> +};
> +
> +static struct nand_bbt_descr bbt_mirror_descr = {
> +	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE |
> +		   NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
> +	.offs =	2,
> +	.len = 4,
> +	.veroffs = 6,
> +	.maxblocks = 4,
> +	.pattern = mirror_pattern,
> +};
> +
> +#endif
> +

Won't veroffs = 6 conflict with ECC in the MXC_NFC_V1 case?

What about 8-bit small page support, in which case the bad block marker
is at offset 5?

>  int board_nand_init(struct nand_chip *this)
>  {
>  	struct mtd_info *mtd;
>  	uint16_t tmp;
>  	int err = 0;
>  
> +#ifdef CONFIG_SYS_NAND_USE_FLASH_BBT
> +
> +	this->options = NAND_USE_FLASH_BBT;
> +	this->bbt_td = &bbt_main_descr;
> +	this->bbt_md = &bbt_mirror_descr;
> +
> +#endif

Please remove those blank lines inside the ifdef.

-Scott