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
a historical leftover, and very few drivers actually look at it. But the
PCI `ncr' driver does, and if this field is not initialized to its default
value, that driver will fall over flat on its face when it attempts to get
sense data from a target.
fix 'cd' driver's NCD_SCSI bogosity (was using testing wrong macro!)
clean up in various ways:
* make common atapi_mode_{sense,select}() functions.
* put ATAPI data structures in more sensible headers, split up by
device type.
* include headers a bit more carefully.
* pass flags to attachment-specific cd functions, and use them.
* get rid of SCSI bits in scsipi_base.h's scsipi_make_xs(), move
them into the correct place in scsi_base.c.
* fix minor typo in struct name in scsipiconf.h (which was apparently
never used except in a #define later in the same file).
* use __attribute__ to force 4-byte alignment for xs command store,
so that architectures trying to bus_space_write_multi_N() (where
N > 1) that data to a controller won't lose.
* clean up a few comments in typos, and make a few #defines easier to
understand/maintain.
* rename cd_link.h to cdvar.h (via repository copy). This is exactly
what a 'var' file is supposed to be.
- Indent with tab of width 8.
- Use four column to indent continuation line.
- Fold long line if possible.
- Use return (xx) instead of return xx.
- Compare pointer against NULL instead of testing like boolean.
- Delete whitespace at the end of line.
- Delete whitespace in front of function call operator.
- Delete whitespace after cast.
- Dereference a pointer to function explicitly.
- Add an empty line after local variable declaration.
- Use NULL instead of (char *)0.
- Dont use block for single statement.
(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.
thorpej