[8733] in linux-scsi channel archive
Re: SCSI driver question
daemon@ATHENA.MIT.EDU (Mark Elkins)
Mon May 1 15:04:59 2000
Message-ID: <20000501185229.559.qmail@web4503.mail.yahoo.com>
Date: Mon, 1 May 2000 11:52:29 -0700 (PDT)
From: Mark Elkins <mokes2001@yahoo.com>
To: Eric Lee Green <eric@estinc.com>
Cc: linux-scsi@vger.rutgers.edu
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Hello,
I checked out the generic SCSI interface, but it
offers indirect transfers (i.e. user data is copied to
kernel buffers). I would like to perform direct
transfers (thus I can give a physical address, or a
virtual address which I know is mapped to a specific
physical address). Does anyone know of an appropriate
mechanism?
Thanks,
-Mark
--- Eric Lee Green <eric@estinc.com> wrote:
> Mark Elkins wrote:
> > I'm trying to directly read/write a SCSI disk. By
> > "direct" access I mean that I do not want the data
> to
> > be buffered, and that I can supply a physical
> address
> > (or a virtual address following a bus_to_virt
> call)
> > for the data buffers. Thus, the data to be written
> (or
> > buffers for read data) can possibly even be
> located on
> > a PCI device. Does anyone have any idea as to the
> > appropriate entry point/mechanism for such
> operations?
> >
> > Related to this, can anyone point me to good
> > documentation regarding the Linux SCSI
> architecture?
> > Most of the docs I've seen are ancient, nothing
> > pertaining to 2.2 or higher...
>
> "Read the Source, Luke" seems to be the usual
> response to documentation
> problems with the Linux kernel. Rather unsatisfying,
> but (shrug).
>
> http://www.torque.net/sg/
>
> is the place where the Linux SCSI Generic driver
> lives. This gives you direct
> access to the SCSI bus via an interface to the
> low-level SCSI device drivers.
> There is sample source code there showing you how to
> do various things such
> as, e.g., read/write blocks of data on a hard drive
> via the low-level READ and
> WRITE commands.
>
> --
> Eric Lee Green
> eric@estinc.com
> Software Engineer Visit our Web
> page:
> Enhanced Software Technologies, Inc.
> http://www.estinc.com/
> (602) 470-1115 voice (602)
> 470-1116 fax
>
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