[PATCH] NCR5380: Add disconnect_mask module parameter

[Finn Thain <fthain@telegraphics.com.au>]

Add a module parameter to inhibit disconnect/reselect for individual
targets. This gains compatibility with Aztec PowerMonster SCSI/SATA
adapters with buggy firmware. (No fix is available from the vendor.)

Apparently these adapters pass-through the product/vendor of the
attached SATA device. Since they can't be identified from the response
to an INQUIRY command, a device blacklist flag won't work.

Cc: Michael Schmitz <schmitzmic@gmail.com>
Reviewed-and-tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
---
This should be a per-host or per-bus setting and not per-driver
(though in the case of atari_scsi there is only one host).
Is there a better way?
---
 drivers/scsi/NCR5380.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c
index 536426f25e86..d4401c768a0c 100644
--- a/drivers/scsi/NCR5380.c
+++ b/drivers/scsi/NCR5380.c
@@ -129,6 +129,9 @@
 #define NCR5380_release_dma_irq(x)
 #endif
 
+static unsigned int disconnect_mask = ~0;
+module_param(disconnect_mask, int, 0444);
+
 static int do_abort(struct Scsi_Host *);
 static void do_reset(struct Scsi_Host *);
 static void bus_reset_cleanup(struct Scsi_Host *);
@@ -954,7 +957,8 @@ static bool NCR5380_select(struct Scsi_Host *instance, struct scsi_cmnd *cmd)
 	int err;
 	bool ret = true;
 	bool can_disconnect = instance->irq != NO_IRQ &&
-			      cmd->cmnd[0] != REQUEST_SENSE;
+			      cmd->cmnd[0] != REQUEST_SENSE &&
+			      (disconnect_mask & BIT(scmd_id(cmd)));
 
 	NCR5380_dprint(NDEBUG_ARBITRATION, instance);
 	dsprintk(NDEBUG_ARBITRATION, instance, "starting arbitration, id = %d\n",
-- 
2.23.0