http://mail-index.netbsd.org/tech-kern/2003/09/25/0006.html
This adds a device (atabus) between IDE controllers and wd or atapibus, to
have each ATA channel show up in the device tree. Later there will be atabus
devices in /dev, so that we can do IOCTL on them.
Each atabus has its own kernel thread, to handle operations that needs polling,
e.g. reset and others.
Device probing on each bus it defered to the atabus thread creation.
This allows to do the reset and basic device probes in parallel, which reduce
boot time on systems with several pciide controllers.
sector information in the kernel. Doing this uncovered some shortcomings
that should have been pretty obvious with the code committed prior, addressing
the major kludge with a new struct - disk_bacsecinfo to be passed into
DIOCBSLIST.
prempt read operations on matching regions with a failure rather than waiting
for the device to return a failure. The I/O operation must have already failed
MAXRETRIES times before being added to the list - this can generally take up
to 12 seconds.
List is made accessible to userspace via DIOCBSLIST and DIOCBSFLUSH.
Such RAID controllers are actually just IDE controllers with a BIOS that
can create RAID volumes and write the configuration info to config blocks
on the disks. The BIOS can do I/O to these volumes, and the OS must
understand the config blocks and implement RAID in software in order to be
able to use these volumes.
Only SPAN (simple concatenation) and RAID0 are supported at this time,
and writing back config blocks is also not supported at this time. Currently,
only the Promise configuration scheme is supported, although supporting
the Highpoint scheme should not be too difficult.
In any case, this is sufficient to use the Promise RAID0 volume (thus
preserving the win2k AS installation) on this new Intel server I have.
Thanks to Soren Schmidt for doing the work in FreeBSD; it made this
task much easier. The config block parsing code is adapted from his
work.
- move some functions from ata.c to ata_wdc.c or wdc.c.
- add callbacks to struct ata_bustype so that wd.c doesn't call directly
functions from the lower level driver.
kill ata_atapi_attach. Change atapibus to use a struct scsipi_channel instead
of ata_atapi_attach as attach arch. Create a ata_device, compatible with
scsipi_channel, to attach wd.
if an IRQ was not detected, unless the force flag was given. Use this to
detect if the IRQ was for us (closer to shared IRQ for controllers which
don't have their own IRQ handler in pciide.c) and to poll for DMA xfer.
Also makes the timeout recovery code simpler.
- ATAPI cleanup: don't call controller-specific functions from atapiconf.c
(wdc_*), so that it's possible to attach an atapibus to something else
than a wdc/pciide (Hi Lennart :).
Overload struct scsi_adapter with struct atapi_adapter, defined
as struct scsi_adapter + atapi-specific callbacks. scsipi_link still points
to an scsi_adapter, atapi code casts it to atapi_adapter if needed.
Move atapi_softc to atapiconf.h so that it can be used by the underlying
controller code (e.g. atapi_wdc.c).
Add an atapi-specific callback *atapi_probedev(), which probe a drive
in a controller-specific way, allocate the sc_link and fills in the
ataparams if needed. It then calls atapi_probedev() (from atapiconf.c)
to do the generic initialisations and attach the device.
- While I'm there merge and centralise the state definitions in atavar.h.
It should now be possible to use a common ata/atapi routine to set the
drive's modes (will do later).
thorpej