sk/msk no more

Bruce M. Simpson bms at FreeBSD.org
Tue Mar 24 08:07:51 PDT 2009


Wilkinson, Alex wrote:
>     0n Fri, Mar 20, 2009 at 12:42:08PM -0400, John Baldwin wrote: 
>
>     >mcfg is a mechanism for doing faster PCI config access using a memory mapped window.
>
> As opposed to what ?
>   

As opposed to bit-banging all PCI configuration space accesses through a 
couple of low ISA I/O space ports (PCI Configuration Mechanism #1... in 
the PCI SIG specs.) :-)

For years PCI was an x86/Intel only thing, architectures which don't 
have this notion of ISA I/O port space have used memory mapped windows 
like this for years.

cheers,
BMS


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