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
some devices may not be found if the BIOS (which would normally
do the reset at startup) is disabled. Should really be done from the SCSI
layer.
Implement the SCBUSIORESET ioctl.
field in the softc, instead of relying on NPCI > 0. This would
prevent things from compiling if PCI buses were in the config file,
but ahc was attached only to something else than the PCI bus.
(currently only CD-ROM drives on i386). The sys/dev/scsipi system provides 2
busses to which devices can attach (scsibus and atapibus). This needed to
change some include files and structure names in the low level scsi drivers.
this code makes equal sense for memory and I/O space, prefer to map
the PCI front end via memory space (conditionalized on a patchable kernel
variable), and do a bit of other random NetBSD-specific cleanup. (These
changes were sent to Justin Gibbs on March 28.)
- No more distinction between i/o-mapped and memory-mapped
devices. It's all "bus space" now, and space tags
differentiate the space with finer grain than the
bus chipset tag.
- Add memory barrier methods.
- Implement space alloc/free methods.
- Implement region read/write methods (like memcpy to/from
bus space).
This interface provides a better abstraction for dealing with
machine-independent chipset drivers.
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.
