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
to the SCSIPI subsystem.
- Determine more characteristics about the board, including the number
of concurrent commands that the processor can execute at a time.
- Rework memory allocation strategy so that we can do dynamic pre-allocation
of resources according to workload.
Thanks to the Linux Buslogic driver for having some useful comments.
(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.
bit from the extended setup inquiry and key off it to:
- Force synchronous negotiation on targs > 7.
- Read additional information returned by wide cards on inquire setup.
- Read sync period on targs > 7.
- Display sync period/offset on targs > 7.
- Set scsi_link.max_target to 15.
cvs: ----------------------------------------------------------------------
ISA-compatible port space of PCI buslogic cards.
* Add call to bha_pci.c to disable the ISA-compatible ports of a PCI
device. The ISA-compatible ports are enabled by default, which
causes the card to be autoconfigured a second time as an ISA device,
which appears to deadlock the card.
* Change bha_cmd() to return the number of bytes it actually received
in response to a command, or -1 on error.
* Use heuristics (checking for bha-only registers, and checking the size
of the response to BHA_INQURE_EXTENDED) to bha_find, to make sure the
bha driver never matches an aha (Adaptec 1542 or compatible) device.
A single kernel should now boot on either Adaptec or BusLogic controllers,
provided we always probe for BusLogic devices before Adaptec devices,
but this has not yet been verified.
bouyer