On Sun, 3 Aug 2014, Michael Schmitz wrote:
NCR5380.c lacks support for tagged queueing, while sun3_NCR5380.c and
atari_NCR5380.c have divergent implementations of this.
Might be equivalent for all I've seen - just array vs. bitmap to store
tags..
It is messier than that. setup_use_tagged_queuing is disabled by default
on atari, and enabled by default on sun3. If we don't disable it by
default everywhere then we need to resolve a change to the algorithm: the
following code appears at the beginning of NCR5380_reselect() in
atari_NCR5380.c but appears at the end of that routine in sun3_NCR5380.c.
I still have to try to figure out the implications of this change.
#ifdef SUPPORT_TAGS
/* If the phase is still MSGIN, the target wants to send some more
* messages. In case it supports tagged queuing, this is probably a
* SIMPLE_QUEUE_TAG for the I_T_L_Q nexus.
*/
tag = TAG_NONE;
if (phase == PHASE_MSGIN && setup_use_tagged_queuing) {
/* Accept previous IDENTIFY message by clearing ACK */
NCR5380_write( INITIATOR_COMMAND_REG, ICR_BASE );
len = 2;
data = msg+1;
if (!NCR5380_transfer_pio(instance, &phase, &len, &data) &&
msg[1] == SIMPLE_QUEUE_TAG)
tag = msg[2];
dprintk(NDEBUG_TAGS, "scsi%d: target mask %02x, lun %d sent tag %d at "
"reselection\n", HOSTNO, target_mask, lun, tag);
}
#endif
Changes to NCR5380. are rather major though. I need to carefully go
through the diff again. ISTR trying to run the coroutine as delayed
workqueue instead of immediate but dropped that again for some reason.
I don't think it makes sense to unify NCR5380.c and atari_NCR5380.c at
this stage. The ISA cards' requirements together are more peculiar than,
say, ST-DMA, and are mostly irrelevant to the M68k, ARM and PCI devices.
As an aside, forking NCR5380.c into atari_NCR5380.c, sun3_NCR5380.c and
mac_NCR5380.c (deleted in v2.6.3) was clearly misguided as it never
actually produced a good alternative to NCR5380.c.
Forking just multiplied the maintenance demands, and diminishing man-power
of course lead to neglect and breakage. So I can sympathise with
Christoph's comment in NCR5380.c:
* (Note from hch: unfortunately it was not enough for the different
* m68k folks and instead of improving this driver they copied it
* and hacked it up for their needs. As a consequence they lost
* most updates to this driver. Maybe someone will fix all these
* drivers to use a common core one day..)
But one core is hard, even if you have all the hardware. Two cores is
better than three.
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