Re: [PATCH V3 6/9] mtd: add a new field for ecc info in the nand_flash_dev{}

Brian Norris
2013-04-25T06:58:00Z

Last nitpicks for v3 :)

On Tue, Apr 23, 2013 at 1:54 AM, Huang Shijie <b32955@freescale.com> wrote:
> Add the @ecc_info in the nand_flash_dev{}.
> The lower 16 bits are used to store the ECC bits, while the upper 16 bits
> are used to store the ECC data chunk size.

A bit late on this one, but is there a good reason this wasn't just 2
separate 16-bit fields? We already have a few, and I don't see why
this couldn't be the same.

> Signed-off-by: Huang Shijie <b32955@freescale.com>
> ---
> include/linux/mtd/nand.h | 10 ++++++++++
> 1 files changed, 10 insertions(+), 0 deletions(-)
>
> diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
> index 063e517..f4c7777 100644
> --- a/include/linux/mtd/nand.h
> +++ b/include/linux/mtd/nand.h
> @@ -624,6 +624,10 @@ struct nand_chip {
> { .name = (nm), {{ .dev_id = (devid) }}, .chipsize = (chipsz), \
> .options = (opts) }
>
> +#define NAND_ECC_INFO(strength, size) (((strength) << 16) | (size))

We could redefine this:

#define NAND_ECC_INFO(strength, size) .ecc_strength = (strength),
.ecc_size = (size)

> +#define NAND_ECC_STRENGTH(x) (((x) >> 16) & 0xffff)
> +#define NAND_ECC_SIZE(x) ((x) & 0xffff)

Then we could just drop these unpacking macros.

> /**
> * struct nand_flash_dev - NAND Flash Device ID Structure
> * @name: a human-readable name of the NAND chip
> @@ -641,6 +645,11 @@ struct nand_chip {
> * @options: stores various chip bit options
> * @id_len: The valid length of the @id.
> * @oobsize: OOB size
> + * @ecc_info: The ECC information.
> + * lower 16 bits: store the ECC bits.
> + * upper 16 bits: store the ECC data chunk size.
> + * For example, the "4bit ECC for each 512Byte" can be set with
> + * NAND_ECC_INFO(4, 512) macro.
> */
> struct nand_flash_dev {
> char *name;
> @@ -657,6 +666,7 @@ struct nand_flash_dev {
> unsigned int options;
> uint16_t id_len;
> uint16_t oobsize;
> + uint32_t ecc_info;

This could be split to:

uint16_t ecc_strength;
uint16_t ecc_size;

> };
>
> /**

Brian