s/beggining/beginning/ in comments.

Remove closes 3 & 4 from my licence. Lots of thanks to Soren Jacobsen
for the booring work !

branches: 1.20.74;
Some drives disconnect after the last data phase without a save data pointer
message. In such case we would not update resid with the proper value
(eventually resid would not be updated at all if there was only one data
phase). To fix this, have the script save the offset in the data tables at
disconnect time if there was a transfer, and use this to compute the resid
if the current offset is 0.
Problem reported and patch tested by edwin, Roy Bixler and YAMAMOTO Takashi.
Fix kern/31990 by YAMAMOTO Takashi.

branches: 1.19.2; 1.19.4; 1.19.10;
nuke trailing whitespace

branches: 1.18.4; 1.18.6;
when an unexpected disconnect occurs only compute the resid; do the
real save data pointers when we get the message (or rather, at disconnect
time following the message).
Factor out code to do this, and to deal with xs->resid, in siop_common.c.

Properly compute xs->resid, instead of assuming it'll always be 0 when
a command is done.

branches: 1.16.4;
Remove references to University of California from my copyright notices.

Properly handle messages that we get at reconnect time (other than
SIMPLE_Q_TAG). Some drives start sync/wide negotiation at reconnect time.
Problem reported and fix tested by Andreas Wrede.

branches: 1.14.6;
Fix typo in comment.

branches: 1.13.2; 1.13.4; 1.13.6; 1.13.8;
Move a few things around, to save some JUMP.

Use a u_int32_t in script RAM instead of the SEM bit in ISTAT to pass flags
between script and driver. This allows more than one flag, and is easier to
manage (we almost can't read/write istat outside of the irq handler).

Implement a ring for the completed commands. This avoid a (problematic only
if error occurs after status is collected) race condition
when using the status byte to detect completed commands (a command descriptor
could be recycled before the device disconnected), and make the
interrupt routine handling completed commands more efficient (no need to
scan target * lun * tag array any more).

- We can't share the per-lun DSA entry for untagged and tag table DSA;
there may be tagged commands still running when we queue a request sense
command.
Solve this by using 2 DSA entry per LUN
- Now that we have the command DSA before select, we can load T/L/Q in
SCRATCHC. This makes the selection timeout handler simpler.
- Avoid a race condition when setting the free flag in the cmd ring (see
comment in the script)
- don't forget to update the ID in the head of LUN table after a sync/wide
negotiation. This fixes the command timeout at the first data command
after negotiation (the bus reset handler did update the ID properly,
so subsequent commands were OK).
- for DMA interrupts, clear fifo if it's not empty. Leaving the fifo dirty
would prevent subsequent interrupts from coming in.
- Various improvements in debug messages
- misc cleanups.

For a new command, use the id in the command table and get rid of the ID in the
scheduler slot. This costs a few more instructions but divide the size of the
scheduler ring by 2, saving 1k of onboard RAM (a bus with 15 devices would
overflow the on-board RAM by 128 bytes).

Bump the number of slots in the command ring to 256.

More copyright fixes, pointed out by Thomas. Thanks !

Fix copyrigth.

Bump the space for SCSI messages from 8 to 16 octets, as 8 may not be
enouth for IDENTIFY + TAG + PPR.
Get rid of constants in C code by use of a offsetof macro.

It seems that the script processor continue to exec a few intructions
after the selection timeout is posted but the number executed isn't
reliable. So wait for MSG_OUT rigth after the select so that the state of
the script when the interruption is handled is known.

Add the led_on/led_off script fragments.

Add support for tagged queuing to esiop (256 tags per device).
For this add another indirecton: the DSA in the LUN table points to
a table of DSA indexed by the tag number when tagged command is in use.
For non tagged command, the LUN DSA still points to the tables describing the
xfer directly.

First cut at a esiop driver (enhanced siop). Doesn't implement tagged queuing
yet.
If is restricted to SIOP which implement the load/store instruction, and
has 10 scratch registers (basically, 825 and newer, possibly 770).
It implements a different interface between host and script, using a real
ring for command starts, and improved support for reconnect which will allow
256 tag per device. It uses interrupt on the fly to signal complete command,
which allows several commands to be serviced per interrupt and doesn't require
the script to stop to signal command completion.