[U-Boot] [PATCH V2 1/2] mmc: change magic number to macro define

[Prafulla Wadaskar]

> -----Original Message-----
> From: u-boot-bounces at lists.denx.de [mailto:u-boot-bounces at lists.denx.de]
> On Behalf Of Lei Wen
> Sent: Thursday, October 06, 2011 8:41 PM
> To: Marek Vasut
> Cc: Lei Wen; u-boot at lists.denx.de; Andy Fleming
> Subject: Re: [U-Boot] [PATCH V2 1/2] mmc: change magic number to macro
> define
> 
> Hi Marek,
> 
> On Tue, Oct 4, 2011 at 8:07 PM, Marek Vasut <marek.vasut at gmail.com>
> wrote:
> > On Tuesday, October 04, 2011 08:35:10 AM Lei Wen wrote:
> >> Previous magic number is hard to parse its meaning, change it to
> >> respective macro definition
> >>
> >> Signed-off-by: Lei Wen <leiwen at marvell.com>
> >
> > [..]
> >
> >> --- a/include/mmc.h
> >> +++ b/include/mmc.h
> >> @@ -145,13 +145,15 @@
> >>  /*
> >>   * EXT_CSD fields
> >>   */
> >> -
> >> -#define EXT_CSD_PART_CONF    179     /* R/W */
> >> -#define EXT_CSD_BUS_WIDTH    183     /* R/W */
> >> -#define EXT_CSD_HS_TIMING    185     /* R/W */
> >> -#define EXT_CSD_CARD_TYPE    196     /* RO */
> >> -#define EXT_CSD_REV          192     /* RO */
> >> -#define EXT_CSD_SEC_CNT              212     /* RO, 4 bytes */
> >> +#define EXT_CSD_PARTITIONING_SUPPORT 160     /* RO */
> >> +#define EXT_CSD_ERASE_GROUP_DEF              175     /* R/W */
> >> +#define EXT_CSD_PART_CONF            179     /* R/W */
> >> +#define EXT_CSD_BUS_WIDTH            183     /* R/W */
> >> +#define EXT_CSD_HS_TIMING            185     /* R/W */
> >> +#define EXT_CSD_REV                  192     /* RO */
> >> +#define EXT_CSD_CARD_TYPE            196     /* RO */
> >> +#define EXT_CSD_SEC_CNT                      212     /* RO, 4 bytes
> */
> >> +#define EXT_CSD_HC_ERASE_GRP_SIZE    224     /* RO */
> >>
> >>  /*
> >>   * EXT_CSD field definitions
> >
> > Hi Lei,
> > this is better, but what about structure-based access ?
> >
> > struct somrthing {
> >  u8 a1;
> >  u8 a2;
> > ...
> > };
> >
> > Like this.
> >
> > Also, CC Andy.
> >
> 
> The ext_csd current usage in mmc.c is not too much, here I mean only few
> of
> the fields of the ext_csd is used, also fully definition of ext_csd
> member would seems so huge a structure at its appearence...
> 
> So macro may looks more concise and could parse from its meaning easily
> enough.
> 
> Anyway, more comments on this welcomes. :)

Dear Lei
Using c-struct is our strategy, may be full definition is huge, you may skip them inserting padding in the c-struct.

Regards..
Prafulla . .