Re: APUS bus access

[<gri...@ps...>]

> BTW  Gerard said the driver should be MMIO and not IO_MAPPED. I may try
> turning off I/O mapped and see what happens.  He also said he would have
> liked to work on MMIO, on non-PC hardware I presume, but has no hardware
> to do the work.  Does anyone have any ideas on MMIO vs IO MAPPED?  On
> first thought I'm not sure I understand the differences.

Probably some subtle difference. MMIO should be the way we're used to on the
680x0 and PPC. 'flat' register space in memory. No special tricks required,
just a base-address and some offsets.

I'm not sure what the difference would be between MMIO and IO_MAPPED, but 
perhaps it's some way of mapping the Intel I/O port concept onto 
memory. That my require some tricks when accessing (eg. write register 
number first, then read or write data).

Perhaps Geert has seen this difference before in video-cards? They also
have all sorts of MMIO and I/O mapping stuff.

								Bye, Arno.

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