Subject: Re: change bus_space_barrier() semantic
To: Jason Thorpe <thorpej@shagadelic.org>
From: Wolfgang Solfrank <ws@tools.de>
List: tech-kern
Date: 01/11/2006 11:20:22
Hi,

>>> Yes, modulo the name. Would save us from changing the drivers
>>> that assume implicit barriers.
>>
>>
>> I don't like it. The cross product of behviours, bit-widthes and other
>> options is already enourmous.
>>
>> My personal favorite solution is to stick to the documentation,  
>> explicitly
>> state so and start fixing drivers (where they are broken).
> 
> 
> I would rather have a mapping option.

Hmm, do we really need a runtime option here?

To me it looks like a driver is either written with explicit barriers
in mind, or not.  If it is, we can have some appropriate define before
including <machine/bus.h> and have the bus_space methods leave out the
implicit barriers.  And document that anyone using that driver (i.e.
bus specific frontends) have to map the neccessary regions with the
appropriate flags.

Ciao,
Wolfgang
-- 
ws@TooLs.DE                            Wolfgang Solfrank, TooLs GmbH