[PATCH] tiny-printf: Support %i

[Marek Vasut]

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.