On Fri, Jun 01, 2018 at 12:16:33AM +0200, Stefan Agner wrote:
> Allow to define a NAND chip as a boot device. This can be helpful
> for the selection of the ECC algorithm and strength in case the boot
> ROM supports only a subset of controller provided options.
>
> Signed-off-by: Stefan Agner <ste...@agner.ch>
> ---
> Documentation/devicetree/bindings/mtd/nand.txt | 4 ++++
> drivers/mtd/nand/raw/nand_base.c | 3 +++
> include/linux/mtd/rawnand.h | 6 ++++++
> 3 files changed, 13 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/mtd/nand.txt
> b/Documentation/devicetree/bindings/mtd/nand.txt
> index 8bb11d809429..8daf81b9748c 100644
> --- a/Documentation/devicetree/bindings/mtd/nand.txt
> +++ b/Documentation/devicetree/bindings/mtd/nand.txt
> @@ -43,6 +43,10 @@ Optional NAND chip properties:
> This is particularly useful when only the in-band area is
> used by the upper layers, and you want to make your NAND
> as reliable as possible.
> +- nand-is-boot-medium: Whether the NAND chip is a boot medium. Drivers might
> use
> + this information to select ECC algorithms supported by
> + the boot ROM or similar restrictions.
> +
Shouldn't this be a partition level option? You could conceivably do one
ECC type for boot area and something else for the rest of the NAND.
> - nand-rb: shall contain the native Ready/Busy ids.
>
> The ECC strength and ECC step size properties define the correction
> capability
> diff --git a/drivers/mtd/nand/raw/nand_base.c
> b/drivers/mtd/nand/raw/nand_base.c
> index 9eb5678dd6d0..c8fb7c9855e2 100644
> --- a/drivers/mtd/nand/raw/nand_base.c
> +++ b/drivers/mtd/nand/raw/nand_base.c
> @@ -5826,6 +5826,9 @@ static int nand_dt_init(struct nand_chip *chip)
> if (of_get_nand_bus_width(dn) == 16)
> chip->options |= NAND_BUSWIDTH_16;
>
> + if (of_property_read_bool(dn, "nand-is-boot-medium"))
> + chip->options |= NAND_IS_BOOT_MEDIUM;
> +
> if (of_get_nand_on_flash_bbt(dn))
> chip->bbt_options |= NAND_BBT_USE_FLASH;
>
> diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h
> index 6a82da8c44ce..8e54fcf2fa94 100644
> --- a/include/linux/mtd/rawnand.h
> +++ b/include/linux/mtd/rawnand.h
> @@ -212,6 +212,12 @@ enum nand_ecc_algo {
> */
> #define NAND_WAIT_TCCS 0x00200000
>
> +/*
> + * Whether the NAND chip is a boot medium. Drivers might use this information
> + * to select ECC algorithms supported by the boot ROM or similar
> restrictions.
> + */
> +#define NAND_IS_BOOT_MEDIUM 0x00400000
> +
> /* Options set by nand scan */
> /* Nand scan has allocated controller struct */
> #define NAND_CONTROLLER_ALLOC 0x80000000
> --
> 2.17.0
>
