ncr5380: Remove disused atari_NCR5380.c core driver

Now that atari_scsi and sun3_scsi have been converted to use the NCR5380.c
core driver, remove atari_NCR5380.c. Also remove the last vestiges of its
Tagged Command Queueing implementation from the wrapper drivers.

The TCQ support in atari_NCR5380.c is abandoned by this patch. It is not
merged into the remaining core driver because,

1) atari_scsi defines SUPPORT_TAGS but leaves FLAG_TAGGED_QUEUING disabled
by default, which indicates that it is mostly undesirable.

2) I'm told that it doesn't work correctly when enabled.

3) The algorithm does not make use of block layer tags which it will have
to do because scmd->tag is deprecated.

4) sun3_scsi doesn't define SUPPORT_TAGS at all, yet the the SUPPORT_TAGS
macro interacts with the CONFIG_SUN3 macro in 'interesting' ways.

5) Compile-time configuration with macros like SUPPORT_TAGS caused the
configuration space to explode, leading to untestable and unmaintainable
code that is too hard to reason about.

The merge_contiguous_buffers() code is also abandoned. This was unused
by sun3_scsi. Only atari_scsi used it and then only on TT, because only TT
supports scatter/gather. I suspect that the TT would work fine with
ENABLE_CLUSTERING instead. If someone can benchmark the difference then
perhaps the merge_contiguous_buffers() code can be be justified. Until
then we are better off without the extra complexity.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 2 insertions, 20 deletions

diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c
index a59b71f96365..305330b26349 100644
--- a/drivers/scsi/NCR5380.c
+++ b/drivers/scsi/NCR5380.c
@@ -34,13 +34,6 @@
 /* Adapted for the Sun 3 by Sam Creasey. */
 
 /*
- * Further development / testing that should be done :
- *
- * 4.  Test SCSI-II tagged queueing (I have no devices which support
- * tagged queueing)
- */
-
-/*
  * Design
  *
  * This is a generic 5380 driver.  To use it on a different platform,
@@ -1257,14 +1250,6 @@ static struct scsi_cmnd *NCR5380_select(struct Scsi_Host *instance,
 	 * was true but before BSY was false during selection, the information
 	 * transfer phase should be a MESSAGE OUT phase so that we can send the
 	 * IDENTIFY message.
-	 *
-	 * If SCSI-II tagged queuing is enabled, we also send a SIMPLE_QUEUE_TAG
-	 * message (2 bytes) with a tag ID that we increment with every command
-	 * until it wraps back to 0.
-	 *
-	 * XXX - it turns out that there are some broken SCSI-II devices,
-	 * which claim to support tagged queuing but fail when more than
-	 * some number of commands are issued at once.
 	 */
 
 	/* Wait for start of REQ/ACK handshake */
@@ -1287,9 +1272,6 @@ static struct scsi_cmnd *NCR5380_select(struct Scsi_Host *instance,
 	tmp[0] = IDENTIFY(((instance->irq == NO_IRQ) ? 0 : 1), cmd->device->lun);
 
 	len = 1;
-	cmd->tag = 0;
-
-	/* Send message(s) */
 	data = tmp;
 	phase = PHASE_MSGOUT;
 	NCR5380_transfer_pio(instance, &phase, &len, &data);
@@ -2256,8 +2238,8 @@ static void NCR5380_reselect(struct Scsi_Host *instance)
 	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
 
 	hostdata->connected = tmp;
-	dsprintk(NDEBUG_RESELECTION, instance, "nexus established, target %d, lun %llu, tag %d\n",
-	         scmd_id(tmp), tmp->device->lun, tmp->tag);
+	dsprintk(NDEBUG_RESELECTION, instance, "nexus established, target %d, lun %llu\n",
+	         scmd_id(tmp), tmp->device->lun);
 }
 
 /**