Re: RFC: being more anal about iospace accesses..

[Russell King <rmk@arm.linux.org.uk>]

On Wed, Sep 15, 2004 at 12:16:35PM -0700, Linus Torvalds wrote:
> On Wed, 15 Sep 2004, Geert Uytterhoeven wrote:
> > Before people really start using this: what's the advantage of this scheme
> > compared to e.g. dev->busops->in8(), which some of us have been waiting for
> > since a long time?
> 
> Ehh, exactly why would you wait for that? 
> 
> What this new interface is doing is to slowlt move "ioremap()" users over
> to "pci_iomap()" (and by extension, maybe "sbus_ioremap()" etc if somebody
> ever starts doing that too), which allows you to do the bus- and device-
> specific translation just _once_.

What about (PCI!) bus types where you need to write one register with
the address and one with the data.  (I'm glaring at a certain embedded
CPU produced by a well known large chip manufacturer, which I think we
need to do these games to get byte accesses to work correctly.)

Sometimes unified accessor macros/functions just don't work.

> In other words, I hereby proclaim that anybody who does "dev->busops" is a 
> total idiot.

Good, I'll pass that comment on to other people and maybe we can force
certain sillycon manufacturers to stop selling broken hardware.  Or
maybe the universe will implode.  I think the latter is a more likely
scenario than the former.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
                 2.6 Serial core