Messages in this thread | | | Date | Thu, 25 Apr 2013 23:15:18 -0700 | Subject | Re: [PATCH V3 6/9] mtd: add a new field for ecc info in the nand_flash_dev{} | From | Brian Norris <> |
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On Thu, Apr 25, 2013 at 1:56 AM, Huang Shijie <b32955@freescale.com> wrote: > 于 2013年04月25日 14:57, Brian Norris 写道: > >> >> 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. >> > I just want to make the ecc_strength/ecc_size more coupled for the > nand_flash_dev{}. > If we spilit to two fields. It makes the nand_flash_ids[] less readable.
Sure, that's a decent reason. But how about as an instance of an anonymous struct instead? See my suggestion below.
>>> 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) > > Do this type of macro could be accepted by the kernel?
Something like this should be acceptable, I think, if I can straighten it out so that it compiles right (!)
> I think your macro needs a pair of bracket, such as: > #define NAND_ECC_INFO(strength, size) (.ecc_strength = (strength), .ecc_size > = (size)) > > But if we add the brackets, we will meet a compiler error.
Here's my modification (note the underscores, since we can't have the field .strength in the same macro as the "parameter" strength):
#define ECC_INFO(_strength, _size) { .strength = (_strength), .size = (_size) } #define ECC_STRENGTH(type) ((type)->ecc.strength) #define ECC_SIZE(type) ((type)->ecc.strength)
And replace the field in nand_flash_dev with:
struct { uint16_t strength; uint16_t size; } ecc;
How does that look? It's actually quite similar to the construct Artem used with mfr_id and dev_id, except that we give the struct a name. And this time, it actually compiles!
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