Re: readl/writel: swap or not to swap

From: Yasushi SHOJI
Date: Fri Nov 19 2004 - 02:26:45 EST


Hi Jeff,

At Thu, 18 Nov 2004 23:09:19 -0500,
Jeff Garzik wrote:
>
> > is there any rule we should follow? Is the ppc way the right
> > direction to follow? I can ifdef anytime for my own use but I just
> > want to know what _should_ be done.
>
>
> readl()/writel() are defined as being for the PCI bus (little endian).
> As such, they should swap on big endian platforms.

thanks for your input. so read*() and write*() family should _only_
be used for pci bus?

the "Understanding the linux kernel" state that those macro should be
used for i/o shared memory. and it has three bus listed: isa, vlb,
pci.

I'm a bit confused... i know some arch have bus-dedicated read and
write macro, ie isa_readl(). is this the way to go?

sorry for dumb questions. if this is RTFM thing, just tell me.

thanks,
--
yashi

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