[PATCH] cmd: part: number: remove inconsistent 0x from returned value

[Simon Glass]

Hi,

On Fri, 5 Mar 2021 at 07:33, Stefan Herbrechtsmeier
<stefan.herbrechtsmeier-oss at weidmueller.com> wrote:
>
> Hi Eugeniu,
>
> Am 05.03.2021 um 12:52 schrieb Eugeniu Rosca:
> > Hello Stefan,
> >
> > On Fri, Mar 05, 2021 at 07:39:04AM +0000, Stefan Herbrechtsmeier wrote:
> >> From: Stefan Herbrechtsmeier <stefan.herbrechtsmeier at weidmueller.com>
> >>
> >> The part number sub-command returns the hexadecimal value with a leading
> >> 0x.
> >
> > That's to make sure that:
> >     - users have clear and unequivocal feedback that '10'
> >       returned by the command is really HEX 10, not DEC 10.
> >     - other U-Boot commands which need to take '0x10' as input
> >       will interpret it correctly, regardless of the way these
> >       other commands implement ascii-to-integer conversion.
>
> 'Almost all U-Boot commands expect numbers to be entered in hexadecimal
> input format.' [1]
>
> The filesystem commands use `simple_strtoul(.., 16)` and interpret the
> value as hexadecimal value.
>
> The 0x suggests that a 10 will be interpreted as decimal value and this
> isn't true.
>
> >> This is inconsistent with other values in the command
> >
> > It could be, but it is then better to fix the inconsistency in those
> > commands/sub-commands which add the ambiguity.
>
> Normally you are right but U-Boot by design use hexadecimal values
> without 0x. The env_set_hex functions doesn't use 0x.
>
> >> and U-Boot uses hexadecimal values generally.
> >
> > The key word is "generally", but not always. Some U-Boot commands will
> > process '10' as HEX 10 and some will process 10 as DEC 10. So, in order
> > to avoid these games, I vote for leaving the 0x in place.

I would be very surprised if 10 means 0d10 in a partition number. I
agree that putting a 0x in these values is a dangerous precedent and
will just cause confusion. U-Boot uses hex for addresses and most
arguments

>
> You can avoid it only if you could mark decimal numbers and that is
> impossible.

0d10 is available. People are not used to it though.

Reviewed-by: Simon Glass <sjg at chromium.org>

>
> @Tom: Does U-Boot still expect numbers to be hexadecimal values?
>
> [1] https://www.denx.de/wiki/DULG/UBootCommandLineInterface
>
> >>
> >> Signed-off-by: Stefan Herbrechtsmeier <stefan.herbrechtsmeier at weidmueller.com>
> >>
> >> ---
> >>
> >>   cmd/part.c | 2 +-
> >>   1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/cmd/part.c b/cmd/part.c
> >> index 3395c17b89..56e1852c66 100644
> >> --- a/cmd/part.c
> >> +++ b/cmd/part.c
> >> @@ -152,7 +152,7 @@ static int do_part_info(int argc, char *const argv[], enum cmd_part_info param)
> >>              snprintf(buf, sizeof(buf), LBAF, info.size);
> >>              break;
> >>      case CMD_PART_INFO_NUMBER:
> >> -            snprintf(buf, sizeof(buf), "0x%x", part);
> >> +            snprintf(buf, sizeof(buf), "%x", part);
> >