[9fans] ata au naturel

[9fans] ata au naturel

[erik quanstrom]

the sd raw file is one of the really cool things about
plan 9.  while the raw file works pretty well on ata
devices, there are some things you can't get.

so i spent a little bit working out this problem.
there is a paper at http://www.quanstro.net/plan9/atazz.pdf
i promise this link is legal.  it may also resolve.

the current implementation is in these files in
/n/sources/contrib/quanstro/src/9/^(pc/ahci.h pc/sd*.[ch] pc/fis.[ch] port/devsd.c port/sd.h)

i have modified my pccpu configuration file
with these lines instead of the original.

	sdiahci		pci sdscsi fis
	sdaoe
	sdata		pci sdscsi fis
	sdmv50xx	pci fis

astute readers will notice that all ata drivers
were also modified to support 48-bit lbas.
there are also some fixes for recently-reported
ahci problems.

the implementation has a few rough edges,
but i thought that it was important to get
feedback.  papers and code are easy to modify.

- erik