[PATCH 6/7] ddr: altera: arria10: Change %i to %u for printf

[Marek Vasut]

On 4/15/20 7:44 PM, Tom Rini wrote:
> On Wed, Apr 15, 2020 at 05:16:52PM +0200, Marek Vasut wrote:
>> On 4/15/20 5:14 PM, Tom Rini wrote:
>>> On Wed, Apr 15, 2020 at 04:58:31PM +0200, Marek Vasut wrote:
>>>> On 4/15/20 4:56 PM, Tom Rini wrote:
>>>>> On Wed, Apr 15, 2020 at 02:45:08PM +0200, Marek Vasut wrote:
>>>>>> On 4/15/20 11:00 AM, Ley Foon Tan wrote:
>>>>>>> Tiny printf doesn't support %i, change to %u.
>>>>>>>
>>>>>>> Signed-off-by: Ley Foon Tan <ley.foon.tan at intel.com>
>>>>>>> ---
>>>>>>>  drivers/ddr/altera/sdram_arria10.c | 2 +-
>>>>>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>>>>>
>>>>>>> diff --git a/drivers/ddr/altera/sdram_arria10.c b/drivers/ddr/altera/sdram_arria10.c
>>>>>>> index e3f11984a978..8acf324117af 100644
>>>>>>> --- a/drivers/ddr/altera/sdram_arria10.c
>>>>>>> +++ b/drivers/ddr/altera/sdram_arria10.c
>>>>>>> @@ -195,7 +195,7 @@ static void sdram_init_ecc_bits(u32 size)
>>>>>>>  
>>>>>>>  	dcache_enable();
>>>>>>>  
>>>>>>> -	printf("DDRCAL: Scrubbing ECC RAM (%i MiB).\n", size >> 20);
>>>>>>> +	printf("DDRCAL: Scrubbing ECC RAM (%u MiB).\n", size >> 20);
>>>>>>>  	memset((void *)0x8000, 0, size - 0x8000);
>>>>>>>  	flush_dcache_all();
>>>>>>>  	printf("DDRCAL: Scrubbing ECC RAM done.\n");
>>>>>>
>>>>>> Yes, sadly, tiny printf is broken so we need to patch code to work
>>>>>> around that breakage.
>>>>>
>>>>> Yes, limited by design, thanks for changing.
>>>>
>>>> This code could be used without tiny printf, so this change is unnecessary.
>>>
>>> You've got it backwards.  Code that could be used by tiny printf needs
>>> to use the more limited set of formats.  But this should have been using
>>> %u all along?  %i is for int, %u is unsigned int.
>>
>> That would mean most of U-Boot needs to be limited to the subset of
>> formatting characters supported by tiny printf, which is unrealistic.
> 
> Not at all.  Only the code that's used in SPL and in tiny printf
> situations needs to be limited to reduced set.  Which is why we're at
> 4.5 years in and just now "oh, %i doesn't work?".

I keep running into "oh, %i, such a basic C printf() feature, doesn't
work" again and again, and it makes my work with U-Boot real annoying.
This should be fixed in the printf implementation, not all over the code
base. Also, it prevents sane code reuse, unless we start adding #ifdef
TINY_PRINTF all over the place, which is just ew ...