[U-Boot] [PATCH] lib: time: Add microsecond timer

[Marek Vasut]

On 10/16/19 6:40 PM, Simon Glass wrote:
> Hi Marek,

Hi,

> On Wed, 16 Oct 2019 at 02:55, Marek Vasut wrote:
>>
>> On 10/16/19 3:30 AM, Simon Glass wrote:
>>> Hi Marek,
>>
>> Hi,
>>
>>> On Tue, 15 Oct 2019 at 14:43, Marek Vasut wrote:
>>>>
>>>> Add get_timer_us(), which is useful e.g. when we need higher
>>>> precision timestamps.
>>>
>>> Can we use timer_get_us()? It seems confusing to have two.
>>
>> Nope, that one doesn't have the range (unsigned long vs. u64) and also
>> doesn't behave the same way as old get_timer(). I wanted something which
>> is similar, just for uS instead of mS.
> 
> Can you add comments to your patch to indicate what is going on any
> why to use this?
> 
> Bootstage uses ulong which is enough for about an hour. How long is
> U-Boot running?

It can run as long as anyone needs.

> If you are using differential times, presumably for timeouts, then
> there seems to be little reason to need u64.

I use it for logging timestamps during profiling, e.g. of the EHCI driver.

-- 
Best regards,
Marek Vasut