How to support a TrueIDE (ATA) NANDrive chip

[M. Warner Losh]

In message: <20081205113502.f9871231.stas at FreeBSD.org>
            Stanislav Sedov <stas at freebsd.org> writes:
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: On Thu, 4 Dec 2008 17:23:41 -0500
: Andrew Duane <aduane at juniper.net> mentioned:
: 
: > We have an SST NANDrive chip on our board that supports the simple ATA
: > command set. What's the easiest way to get support for this into our
: > kernel so we can partition and mount the device?
: > 
: > Using "da" and "umass" isn't really an option, since it is neither SCSI,
: > nor attached to USB. Pulling in all of "ata" seems like overkill; all we
: > really need is read/write block and some simple sense commands. They are
: > all synchronous, it's low traffic and we are more concerned with
: > simplicity than performance. Is there some subset of "ata" I can use
: > that won't involve pci bus, controllers, etc? We just want to be able to
: > write the LBA, SECT_CNT, and GO command and read the data.
: > 
: 
: Why not attach the ATA stack to the register space the chip provides.
: Doesn't look like an overkill to me. It should work pretty well.
: I'm using something like this for AT91 CF controller. I'v attached
: it source, it might be useful to you. It's simple enough.

I'd concur.  I believe that we can configure the ata stuff such that
we don't get pci, et al, in this case.  If not, we should fix that.

Warner