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
pci_attach_args *" instead of from four separate parameters which in
all cases were extracted from the same "struct pci_attach_args".
This both simplifies the driver api, and allows for alternate PCI
interrupt mapping schemes, such as one using the tables described in
the Intel Multiprocessor Spec which describe interrupt wirings for
devices behind pci-pci bridges based on the device's location rather
the bridge's location.
Tested on alpha and i386; welcome to 1.5Q
- Bus specific front-end is now responsible for reading EATA configuration
- EATA configuration data is now saved in the softc
- Make synchronous writes work properly
- Don't ignore HBA timeouts in dpt_cmd()
- Prefix eata_cfg's members with `ec_', not `dc_'
