Some devices do not transfer data with proper way on status phase
and it causes bus error in spc_datain_pio() which uses auto xfer
via DREG register on weird x68k hardware.
reading the FIFO status and reading the interrupt status, we could end up
leaving it in the FIFO. Force another round through the loop after reading the
interrupt status until the FIFO reads empty again.
Also, there is no point in having the extra loop to wait for the transfer
command to the controller to be acknowledged, because the transfer loop handles
that just fine -- and getting rid of it fixes another race condition.
- Don't use SCMD_XFR command in message-in phase and status phase.
It causes unexpected hangs on heavy load. Instead transfer data
manually via TEMP register by SCMD_SET_ACK and SCMD_RST_ACK.
- Don't set SCMD_ICPT_XFR in spc_dataout_pio() and spc_msgout().
- Rewrite spc_datain_pio() to handle FIFO more properly.
- disable debug code by default
- use MI minphys()
- add proper delay in spc_find()
- initialize TMOD register in spc_reset()
- wrap a sanity check with #ifdef DIAGNOSTIC (sync with aic6360.c)
- no need to set LUN bits in SCSI command which should be done in mid-layer
- set proper resid even in error case
- fix/remove some bogus comments
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
timeout()/untimeout() API:
- Clients supply callout handle storage, thus eliminating problems of
resource allocation.
- Insertion and removal of callouts is constant time, important as
this facility is used quite a lot in the kernel.
The old timeout()/untimeout() API has been removed from the kernel.
