Date: Fri, 17 Feb 1995 15:13:43 -0800 (PST) From: julian@tfs.com (Julian Elischer) To: dufault@hda.com (Peter Dufault) Cc: freebsd-hackers@freefall.cdrom.com Subject: Re: SCSI and config(8): Done. Message-ID: <m0rfbrr-0003wTC@TFS.COM> In-Reply-To: <199502171257.HAA21778@hda.com> from "Peter Dufault" at Feb 17, 95 07:57:44 am
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>
> I've added support to configure the SCSI system using config(8).
> I'm going to wait for the "slice" code to settle before committing.
this looks good, and I was wondering how to get this information to the
system.. There is the question however of:
if a device doesn't match what's there, how do we find out, and what do we do?
should we have a call in each driver that confirms that it can handle what it sees?
What do we do it it DOESN't match....
how can we force a device that reports itself as type B (eroneously) to be handled
by the driver for type C (I have devices that report as tape but should be type
processor)...
>
> Here is what I did.
>
> This config file entry:
>
> > controller scbus0 at aha0
> >
> > disk sd0 at scbus0 target 0 unit 0
> > disk sd1 at scbus0 target 1
> > disk sd2 at scbus0 target 3
> > device cd? at scbus?
> > tape st0 at scbus0 target 6
>
> Generates this in ioconf.c:
>
> > #include "scsi/scsiconf.h"
> >
> > struct scsi_ctlr_config scsi_cinit[] = {
> > /* driver unit */
> > { "aha", 0 },
> > { 0, 0 }
> > };
> >
> > struct scsi_device_config scsi_dinit[] = {
> > /* type unit cunit target LUN flags */
> > { T_DIRECT, 0, 0, 0, 0, 0x0 },
> > { T_DIRECT, 1, 0, 1, -1, 0x0 },
> > { T_DIRECT, 2, 0, 3, -1, 0x0 },
> > { T_READONLY, '?', '?', -1, -1, 0x0 },
> > { T_SEQUENTIAL, 0, 0, 6, -1, 0x0 },
> > { -1, 0, 0, 0, 0, 0 }
> > };
>
> (cunit in scsi_dinit is the controller unit and is the index into
> the scsi_cinit table for that device)
>
> The SCSI bus (scsi_cinit) table is passing in names instead of
> "isa_dev's", but I wanted to use the adapter name since I'm not
> sure how the PCI stuff wires in.
>
> When you configure a SCSI controller it looks up its bus number by
> driver name and unit number. When there is no match it uses the
> lowest unused bus number greater than the highest configured bus
> number.
for this to really work properly, we need to disable the autonumbering of
the adapters, so that if aha- dies, aha1 doesn't suddenly become aha0..
>
> (I have to look at how the multiple SCSI bus adapters work - I
> suppose both busses have the same driver and adapter unit number,
> so this current scheme may not work: I may need driver, unit and
> bus in the scsi_cinit table.)
controller scbus0 at ahx0
controller scbus1 at ahx0
I guess Every layer in the hierarchy needs some sort of 'subunit'
field... in isa it's port-address,
in scsi it's target,
in adapters it's unit#, similar to wd0 and wd1
I guess it means adding a field to the structure..
We are slowely heading in the direction of NetBSD(& BSDI I think)
config, in which the softc structure is allocated by the
config routine, and every layer in the hierarchy
is defined the same way......
>
> When you configure a device it looks through the dinit table for
> the unit to use. Each type (T_DIRECT == "sd", etc) is handled
> independently and the same approach is used as for the busses: If
> there is an exact match then that is used, if there is no match
> you use the lowest unused unit number greater than the highest
> configured unit number. Unknown LUNS (LUN == -1) are treated as
> LUN 0 for matching.
>
> All information from the config file is stored in the structures
> so you can go backwards from the structures to the config if you
> want.
>
> For current config files this approach degenerates into the current
> autocounting scheme.
>
> For new config files this becomes "use assignments when provided,
> then autocount beginning after the highest assigned number".
yes....
now, what about devices that are turned off and probed later when turned on..?
>
> Peter
>
> --
> Peter Dufault Real Time Machine Control and Simulation
> HD Associates, Inc. Voice: 508 433 6936
> dufault@hda.com Fax: 508 433 5267
>
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