Re: [PATCH] mtd: nand: hynix: add support for 20nm NAND chips

[Boris Brezillon <boris.brezillon@free-electrons.com>]

Hi Martin,

Le Sat,  5 Aug 2017 14:16:24 +0200,
Martin Blumenstingl <martin.blumenstingl@googlemail.com> a écrit :

> According to the datasheet of the H27UCG8T2BTR the NAND Technology field
> (6th byte of the "Device Identifier Description", bits 0-2) the
> following values are possible:
> - 0x0 = 48nm
> - 0x1 = 41nm
> - 0x2 = 32nm
> - 0x3 = 26nm
> - 0x4 = 20nm
> - (all others are reserved)
> 
> Fix this by extending the mask for this field to allow detecting value
> 0x4 (20nm) as valid NAND technology.
> Without this the detection of the ECC requirements fails, because the
> code assumes that the device is a 48nm device (0x4 & 0x3 = 0x0) and
> aborts with "Invalid ECC requirements" because it cannot map the "ECC
> Level". Extending the mask makes the ECC requirement detection code
> recognize this chip as <= 26nm and sets up the ECC step size and ECC
> strength correctly.

Applied.

> 
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> ---
>  drivers/mtd/nand/nand_hynix.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/nand/nand_hynix.c b/drivers/mtd/nand/nand_hynix.c
> index b12dc7325378..bd9a6e343848 100644
> --- a/drivers/mtd/nand/nand_hynix.c
> +++ b/drivers/mtd/nand/nand_hynix.c
> @@ -477,7 +477,7 @@ static void hynix_nand_extract_ecc_requirements(struct nand_chip *chip,
>  		 * The ECC requirements field meaning depends on the
>  		 * NAND technology.
>  		 */
> -		u8 nand_tech = chip->id.data[5] & 0x3;
> +		u8 nand_tech = chip->id.data[5] & 0x7;

We should probably define macros to extract information from ID bytes
at some point, but let's keep that for later.

>  
>  		if (nand_tech < 3) {
>  			/* > 26nm, reference: H27UBG8T2A datasheet */
> @@ -533,7 +533,7 @@ static void hynix_nand_extract_scrambling_requirements(struct nand_chip *chip,
>  		if (nand_tech > 0)
>  			chip->options |= NAND_NEED_SCRAMBLING;
>  	} else {
> -		nand_tech = chip->id.data[5] & 0x3;
> +		nand_tech = chip->id.data[5] & 0x7;
>  
>  		/* < 32nm */
>  		if (nand_tech > 2)