[lkml]   [2001]   [Jul]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC] I/O Access Abstractions
>  - Parsing of this cookie on each inx/outx access, which can
> take a bit of time (typically looking up the host bridge)

It depends on the implementation obviously, but its typically something like

take lock
writew(port&0xFFFF, port&0xFFFF0000);
writew(data, port&0xFFFF0000+1);
drop lock

Assuming you can drop the bridges on 64K boundaries in pci mem space, or
one extra deref and a register load if not.

Can you give me an idea of what sort of cookie decoding a PPC/PMac would need
and why - Im working off things like pa-risc so I dont have a full picture.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 12:55    [W:0.056 / U:0.868 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site