From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mike Frysinger <vapier@gentoo.org>
Date: Tue, 31 Mar 2009 07:25:19 -0400
Subject: [U-Boot] core ticks/timer code
In-Reply-To: <20090331102823.A2F9883797DC@gemini.denx.de>
References: <200903272130.26825.vapier@gentoo.org>
	<200903310513.09082.vapier@gentoo.org>
	<20090331102823.A2F9883797DC@gemini.denx.de>
Message-ID: <200903310725.20652.vapier@gentoo.org>
List-Id: <u-boot.lists.denx.de>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
To: u-boot@lists.denx.de

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 ...
-mike
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 836 bytes
Desc: This is a digitally signed message part.
Url : http://lists.denx.de/pipermail/u-boot/attachments/20090331/eb32f988/attachment.pgp