This is a completely rewritten scsipi_xfer execution engine, and the
associated changes to HBA drivers. Overview of changes & features:
- All xfers are queued in the mid-layer, rather than doing so in an
ad-hoc fashion in individual adapter drivers.
- Adapter/channel resource management in the mid-layer, avoids even trying
to start running an xfer if the adapter/channel doesn't have the resources.
- Better communication between the mid-layer and the adapters.
- Asynchronous event notification mechanism from adapter to mid-layer and
peripherals.
- Better peripheral queue management: freeze/thaw, sorted requeueing during
recovery, etc.
- Clean separation of peripherals, adapters, and adapter channels (no more
scsipi_link).
- Kernel thread for each scsipi_channel makes error recovery much easier
(no more dealing with interrupt context when recovering from an error).
- Mid-layer support for tagged queueing: commands can have the tag type
set explicitly, tag IDs are allocated in the mid-layer (thus eliminating
the need to use buggy tag ID allocation schemes in many adapter drivers).
- support for QUEUE FULL and CHECK CONDITION status in mid-layer; the command
will be requeued, or a REQUEST SENSE will be sent as appropriate.
Just before the merge syssrc has been tagged with thorpej_scsipi_beforemerge
dev/microcode/aic7xxx_seq.h,
dev/ic/aic7xxxreg.h:
Remove intrinsic knowledge about SDTR and WDTR messages and replace it
with a generic message system that allows the kernel driver to handle
SDTR, WDTR and any other type of extended message it chooses too. This
makes the sequencer code much simpler, makes extended message handling
debuggable since the bulk of the work is in the kernel driver, and saves
lots of instruction space.
Regen microcode header file.
dev/ic/aic7xxx.c, dev/ic/aic7xxxvar.h:
Add code to handle WDTR and SDTR negotiation in light of the changes in
the message interface to the sequencer. Don't reject targets that
negotiate async by sending an SDTR with a 0 offset. Use an sdtr message
with 0,0 to negotiate async when a target suggests a period that is too
long for us to handle. Some tape and cdrom drives don't like us doing
the message reject that we did in the past.
Fix a problem with handing the QUEUE FULL condition.
Fix a race condition (most likely the cause of the SCB paging problems) that
might allow the sequencer to get unpaused before the condition that caused
it to be paused (a SEQINT) was handled.
Race condition pointed out by Doug Ledford <dledford@dialnet.net> and
by "Dan Willis" <dan@plutotech.com>.
dev/pci/ahc_pci.c:
Add support for the 2940AU, an aic7860 based controller.
dev/pci/pcidevs.h, dev/pci/pcidevs_data.h:
Add product IDs for the 2940AU, aic7860 and aic7855.
Regen data file.
scsi/scsi_message.h:
Add MSG_EXT_SDTR_LEN and MSG_EXT_WDTR_LEN - the length of bytes in these
extended messages.
Thanks to Chuck Cranor <chuck@maria.wustl.edu> for testing these changes
out for me.
