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List:       linux-ia64
Subject:    Re: [PATCH] add legacy I/O and memory access routines to /proc/bus/pci API
From:       Jesse Barnes <jbarnes () engr ! sgi ! com>
Date:       2004-12-16 16:26:31
Message-ID: 200412160826.32315.jbarnes () engr ! sgi ! com
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On Thursday, December 16, 2004 6:55 am, Benjamin Herrenschmidt wrote:
> On Wed, 2004-12-15 at 09:00 -0800, Jesse Barnes wrote:
> > Good, because that's exactly what it does.  The arch is responsible for
> > returning the legacy I/O port or legacy ISA memory base address given a
> > pci_dev, which is used as a base for the page offset passed into mmap. 
> > So e.g. mmap(..., 0xa0000) after doing ioctl(fd,
> > PCIIOC_MMAP_IS_LEGACY_MEM, ...) would get you the VGA framebuffer for the
> > device corresponding to 'fd'.
>
> Sounds good... The only thing is a pci_dev may not be available if you
> have a PCI->ISA bridge, tho you may just use the pci_dev of the
> bridge...

Well, you'll have to have a fake one at least.  Remember the fds used in the 
above example come from fd = open("/proc/bus/pci/BB/SS.F", O_RDWR)...

Jesse
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