Messages in this thread | | | Subject | Re: [RFC] I/O Access Abstractions | Date | Tue, 03 Jul 2001 08:55:16 +0100 | From | David Howells <> |
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> The question I think being ignored here is. Why not leave things as is. The > multiple bus stuff is a port specific detail hidden behind readb() and > friends.
This isn't so much for the case where the address generation is done by a simple addition. That could be optimised away by the compiler with an entirely inline function (as per David Woodhouse's suggestion).
It's far more important for non-x86 platforms which only have a single address space and have to fold multiple external address spaces into it.
For example, one board I've got doesn't allow you to do a straight memory-mapped I/O access to your PCI device directly, but have to reposition a window in the CPU's memory space over part of the PCI memory space first, and then hold a spinlock whilst you do it.
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