Re: [patch 2.6.24 3/6] spi_bfin: wait for tx to complete on some cs_chg paths

[David Brownell <david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>]

On Friday 01 February 2008, Bryan Wu wrote:
> 
> > > > +         while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
> > > > +                 cpu_relax();
> > > 
> > > I'd suggest that this commonly-occurring code sequence be implemented in a
> > > standalone function.
> > 
> > The bitmask to check can be a parameter too, as well as the
> > termination result after the mask.  That will allow other loops
> > to get properly limited too -- e.g. wait till RXS or TXS clears,
> > not just SPIF getting set.
> > 
> 
> Before SPIF getting set, we do wait for RXS or TXS clears in the code,
> right?

Sure, but it's the same kind of loop-forever thing.
All "loop-forever" primitives should be replaced by
ones that have some kind of ceiling, since it's far
from unheard-of that hardware glitch.

My observation was that the standalone function
can trivially handle "loop-till-set" as well as
"loop-till-clear".

- Dave


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