[PATCH] tiny-printf: Support %i

[Simon Glass]

Hi Marek,

On Tue, 14 Apr 2020 at 10:32, Marek Vasut <marex at denx.de> wrote:
>
> On 4/14/20 4:41 PM, Simon Glass wrote:
> > Hi Marek,
> >
> > On Tue, 14 Apr 2020 at 07:41, Marek Vasut <marex at denx.de> wrote:
> >>
> >> On 4/14/20 3:26 PM, Tom Rini wrote:
> >>> On Tue, Apr 14, 2020 at 02:24:18PM +0200, Marek Vasut wrote:
> >>>> On 4/14/20 5:03 AM, Tom Rini wrote:
> >>>>> On Tue, Apr 14, 2020 at 03:17:16AM +0200, Marek Vasut wrote:
> >>>>>> On 4/14/20 1:27 AM, Tom Rini wrote:
> >>>>>>> On Fri, Apr 10, 2020 at 08:54:49PM +0200, Marek Vasut wrote:
> >>>>>>>
> >>>>>>>> The most basic printf("%i", value) formating string was missing,
> >>>>>>>> add it for the sake of convenience.
> >>>>>>>>
> >>>>>>>> Signed-off-by: Marek Vasut <marex at denx.de>
> >>>>>>>> Cc: Simon Glass <sjg at chromium.org>
> >>>>>>>> Cc: Stefan Roese <sr at denx.de>
> >>>>>>>> ---
> >>>>>>>>  lib/tiny-printf.c | 3 ++-
> >>>>>>>>  1 file changed, 2 insertions(+), 1 deletion(-)
> >>>>>>>>
> >>>>>>>> diff --git a/lib/tiny-printf.c b/lib/tiny-printf.c
> >>>>>>>> index 1138c7012a..8fc7e48d99 100644
> >>>>>>>> --- a/lib/tiny-printf.c
> >>>>>>>> +++ b/lib/tiny-printf.c
> >>>>>>>> @@ -242,6 +242,7 @@ static int _vprintf(struct printf_info *info, const char *fmt, va_list va)
> >>>>>>>>                                  goto abort;
> >>>>>>>>                          case 'u':
> >>>>>>>>                          case 'd':
> >>>>>>>> +                        case 'i':
> >>>>>>>>                                  div = 1000000000;
> >>>>>>>>                                  if (islong) {
> >>>>>>>>                                          num = va_arg(va, unsigned long);
> >>>>>>>> @@ -251,7 +252,7 @@ static int _vprintf(struct printf_info *info, const char *fmt, va_list va)
> >>>>>>>>                                          num = va_arg(va, unsigned int);
> >>>>>>>>                                  }
> >>>>>>>>
> >>>>>>>> -                                if (ch == 'd') {
> >>>>>>>> +                                if (ch != 'u') {
> >>>>>>>>                                          if (islong && (long)num < 0) {
> >>>>>>>>                                                  num = -(long)num;
> >>>>>>>>                                                  out(info, '-');
> >>>>>>>
> >>>>>>> How much does the size change and where do we see this as a problem?
> >>>>>>
> >>>>>> Any code which uses %i in SPL just misbehaves, e.g.
> >>>>>> printf("%s[%i] value=%x", __func__, __LINE__, val);
> >>>>>> prints function name and then incorrect value, because %i is ignored.
> >>>>>> This is also documented in the commit message.
> >>>>>>
> >>>>>> U-Boot grows in size massively due to all the DM/DT bloat which is being
> >>>>>> forced upon everyone, but there the uncontrolled growth is apparently OK
> >>>>>> even if it brings no obvious improvement, rather the opposite. And yet
> >>>>>> here, size increase suddenly matters? Sorry, that's not right.
> >>>>>>
> >>>>>> The code grows by 6 bytes.
> >>>>>
> >>>>> Yes, it matters for _tiny-printf_ as that's where we have little to no
> >>>>> room for growth.
> >>>>
> >>>> How many systems that use tiny-printf in SPL are also forced to use DM
> >>>> in SPL ?
> >>>
> >>> I don't know how many times I've said no one is forced to switch to DM
> >>> in SPL.
> >>
> >> This is beside the point, there are boards which use SPL and DM, because
> >> the non-DM drivers are steadily going away. So the growth in SPL size is
> >> there, either directly or as a side-effect.
> >
> > I think this is a good point. For serial we have a debug UART. I am
> > think it would be useful to have a 'simple bypass' for more
> > subsystems. For example, for I2C we could have a simple option to
> > access a single I2C driver directly, bypassing driver model. Of course
> > this is painful to do before we have completed I2C migration.
>
> Right. Although it could be prototyped e.g. on the UART subssystem,
> which is a good candidate.

Yes it is on my mind, once i get my lab working properly. Will have a
think about it...

Regards,
Simon