[U-Boot] [RFC][Timer API] Revised Specification - Implementation details

[Reinhard Meyer <u-boot@emk-elektronik.de>]

Dear Graeme Russ,
> Hi Reinhard,
>
> On Tue, May 31, 2011 at 4:57 AM, Reinhard Meyer
> <u-boot@emk-elektronik.de>  wrote:
>> Dear ALL,
>>
>> it still escapes me why everyone tries to make things so complicated INSIDE the loop.
>>
>> Why not just define an API like this:
>>
>> u32 timeout = make_timeout(5); /* minimum 5 millisecond timeout */
>> u32 start = get_timer();
>>
>> while ((get_timer() - start)<  timeout)
>>     ...
>
> The would work if we typedef'd 'timeout'. Otherwise, one runs the risk of
> not calling make_timeout() and assuming get_timer() always has a 1ms
> resolution

If you think people cannot follow API conventions, then typedef it...

>
>> make_timeout() can be arch/soc/platform specific and take into account to return at least
>> such a value that the timeout is never cut short. (In case of a 10 ms NIOS timer,
>> make_timeout(5) would have to return the value 20, resulting in a real timeout of at least
>> 10 ms but upto 20 ms )
>
> What about this:
>
> 	u32 start = get_timer();
>
> 	while (!timer_expired(start, timeout))
> 		...

Again.. why put the complicated calculations INSIDE the loop?

>
>> If anyone sees the need, make_timeout (or what ever it might be called) could have
>> a second parameter, indicating whether round up or round down is desired.
>>
>> ...
>>
>> I also agree to remove the parameter of get_timer(), but we should also get rid of
>> CONFIG_SYS_HZ.
>
> Wholeheartedly agree

Regards,
Reinhard