MISC CHANGES
Add a new async event- ISP_TARGET_NOTIFY_ACK, that will guarantee
eventual delivery of a NOTIFY ACK. This is tons better than just
ignoring the return from isp_notify_ack and hoping for the best.
Clean up the lower level lun enable code to be a bit more sensible.
Fix a botch in isp_endcmd which was messing up the sense data.
Fix notify ack for SRR to use a sensible error code in the case
of a reject.
Clean up and make clear what kind of firmware we've loaded and
what capabilities it has.
FULL (252 byte) SENSE DATA
In CTIOs for the ISP, there's only a limimted amount of space
to load SENSE DATA for associated CHECK CONDITIONS (24 or 26
bytes). This makes it difficult to send full SENSE DATA that can
be up to 252 bytes.
Implement MODE 2 responses which have us build the FCP Response
in system memory which the ISP will put onto the wire directly.
On the initiator side, the same problem occurs in that a command
status response only has a limited amount of space for SENSE DATA.
This data is supplemented by status continuation responses that
the ISP pushes onto the response queue after the status response.
We now pull them all together so that full sense data can be
returned to the periph driver.
This is supported on 23XX, 24XX and 25XX cards.
This is also preparation for doing >16 byte CDBs.
FC TAPE
Implement full FC-TAPE on both initiator and target mode side. This
capability is driven by firmware loaded, board type, board NVRAM
settings, or hint configuration options to enable or disable. This
is supported for 23XX, 24XX and 25XX cards.
On the initiator side, we pretty much just have to generate a command
reference number for each command we send out. This is FCP-4 compliant
in that we do this per ITL nexus to generate the allowed 1 thru 255
CRN.
In order to support the target side of FC-TAPE, we now pay attention
to more of the PRLI word 3 parameters which will tell us whether
an initiator wants confirmed responses. While we're at it, we'll
pay attention to the initiator view too and report it.
On sending back CTIOs, we will notice whether the initiator wants
confirmed responses and we'll set up flags to do so.
If a response or data frame is lost the initiator sends us an SRR
(Sequence Retransmit Request) ELS which shows up as an SRR notify
and all outstanding CTIOs are nuked with SRR Received status. The
SRR notify contains the offset that the initiator wants us to restart
the data transfer from or to retransmit the response frame.
If the ISP driver still has the CCB around for which the data segment
or response applies, it will retransmit.
However, we typically don't know about a lost data frame until we
send the FCP Response and the initiator totes up counters for data
moved and notices missing segments. In this case we've already
completed the data CCBs already and sent themn back up to the periph
driver. Because there's no really clean mechanism yet in CAM to
handle this, a hack has been put into place to complete the CTIO
CCB with the CAM_MESSAGE_RECV status which will have a MODIFY DATA
POINTER extended message in it. The internal ISP target groks this
and ctl(8) will be modified to deal with this as well.
At any rate, the data is retransmitted and an an FCP response is
sent. The whole point here is to successfully complete a command
so that you don't have to depend on ULP (SCSI) to have to recover,
which in the case of tape is not really possible (hence the name
FC-TAPE).
Sponsored by: Spectralogic
MFC after: 1 month