[U-Boot] [PATCH v1 (WIP) 09/16] [Timer]Replace get_timer() usage in drivers/block/

[Simon Glass]

Hi Graeme,

On Tue, Jun 28, 2011 at 10:19 PM, Graeme Russ <graeme.russ at gmail.com> wrote:
> Hi Reinhard,
>
> On Wed, Jun 29, 2011 at 3:06 PM, Reinhard Meyer
> <u-boot at emk-elektronik.de> wrote:
>> Dear All,
>>>
>>> Well I know i have asked this before, but I feel I should ask again
>>> because I didn't like the answer much.
>>>
>>> Imagine we change this code to:
>>>
>>> ts = time_now_ms() + msec
>>> do {
>>> ...
>>> } while (time_since_ms(ts)<  0);
>>>
>>> That should be legal, right? But I don't think this can work since the
>>> 'since' functions return an unsigned.
>>>
>>> [aside: this provides for another idiom that I think we talked about:
>>>
>>> ts = time_future_ms(msec)
>>> do {
>>> ...
>>> } while (!time_passed(ts))
>>>
>>> which I am not at all suggesting should be in the API :-)
>>> end aside]
>>
>> I still vouch for this concept, which is simple, clean, and easy to
>> understand.
>
> It really is a matter of personal taste ;) I find
>
>        u32 start = time_now_ms();
>
>        do {
>                ...blah...
>        } while(time_since_ms(start) < timeout);
>
> much easier to understand (Do whatever while time elapsed since I started
> is less than the timeout)
>
>        u32 end = time_future_ms(timeout);
>
>        do {
>                ...blah...
>        } while(time_now_ms() < end);
...

Actually:

} while (time_passed_ms(end))

but anyway I agree it is a matter of taste and I'm quite happy with
the approach here at the moment.

But what about my question about signed ints for deltas?

Regards,
Simon