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From: gibbs@narnia.plutotech.com (Justin T. Gibbs)
Subject: Bus/Processor specific I/O methods - was Re: Beginning SPARC port
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To: Amancio Hasty <hasty@rah.star-gate.com>
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NetBSD has already dealt with this issue.  It's called "bus.h".  All
of the new CAM SCSI drivers use a FreeBSD version of this file to
perform device I/O.  It also covers DMA and in fact the ISA bounce
buffers that are used in CAM use "bus DMA" instead of the older
bounce buffer scheme used in current.  We shouldn't re-invent the
wheel unless there are sound reasons to do so.  Please review these
files from a recent CAM snapshot to see if this is an acceptable
solution to the problem:

sys/i386/include/bus.h
sys/i386/i386/busdma_machdep.c

And to see how the APIs are used:
sys/dev/aic7xxx/aic7xxx.h
sys/dev/aic7xxx/aic7xxx.c
sys/pci/ahc_pci.c

These files are available in diff format in the archive:

ftp://ftp.FreeBSD.org/pub/FreeBSD/cam/cam-971209.diffs.gz

-- 
Justin T. Gibbs
===========================================
  FreeBSD - Turning PCs into workstations
===========================================