[U-Boot] core ticks/timer code

[Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>]

On 07:25 Tue 31 Mar     , Mike Frysinger wrote:
> On Tuesday 31 March 2009 06:28:23 Wolfgang Denk wrote:
> > In message Mike Frysinger wrote:
> > > > I'll propose a new design with the following Requierement
> > > >
> > > > Generic delay function implementation
> > > >  - ndelay()
> > > >  - udelay()
> > > >  - mdelay()
> > > >
> > > > Generic helper
> > > >  - khz2cycles()
> > > >  - hz2cycles()
> > > >  - cs2ns()
> > > >
> > > > Timer API
> > > >  - timer_init()		- setup the timer
> > > >  - timer_reset()	- reset the timer (use in case of overflow)
> > > >  - get_ticks()		- return the current ticks
> > > >  - get_cycles()		- return the ticks frequency in ns
> > >
> > > do you have real use cases here ?  i'd actually propose the opposite:
> > > kill off the notion of "ticks", "cycles", and "hz".  i dont think
> > > ndelay() is really necessary, and mdelay() is a simple macro on top of
> > > udelay().  that leaves us with really only the three functions we have
> > > today: timer_init(), get_timer(), and reset_timer().  we clarify that the
> > > function operates in terms of milliseconds and blam, it's all so simple
> > > now.
> >
> > Agreed (except that we probably  cannot  completely  throw  away  the
> > tick;  IIRC  there  are  cases  in early startup when nothing else is
> > available yet).
> 
> hrm, i can see that.  but you agree that most use of ticks in common code can 
> be converted to get_timer() ?  on Blackfin systems (and it isnt alone going by 
> a grep), the ticks interface simply returns get_timer(0), so clearly we should 
> be able to convert common code to all use get_timer(0).  that'd leave the 
> ticks interface as optional ... for the systems that need early time sources, 
> they can implement/use it as they need without bringing down everyone else.
> 
> i wouldnt mind starting a patch series for post 2009.05 to clean this up ...
I've in mind too maybe I'll send a first version within few days for a arm soc
and a blackfin based on u-boot-v2

Best Regards,
J.