diff --git a/drivers/scsi/atari_NCR5380.c b/drivers/scsi/atari_NCR5380.c
index 7955221..1331b8c 100644
--- a/drivers/scsi/atari_NCR5380.c
+++ b/drivers/scsi/atari_NCR5380.c
@@ -71,6 +71,9 @@
  * 1.  Test linked command handling code after Eric is ready with
  *     the high level code.
  */
+
+/* Adapted for the sun3 by Sam Creasey. */
+
 #include <scsi/scsi_dbg.h>
 #include <scsi/scsi_transport_spi.h>
 
@@ -458,6 +461,7 @@
 
 static void merge_contiguous_buffers(struct scsi_cmnd *cmd)
 {
+#if !defined(CONFIG_SUN3)
 	unsigned long endaddr;
 #if (NDEBUG & NDEBUG_MERGING)
 	unsigned long oldlen = cmd->SCp.this_residual;
@@ -482,6 +486,7 @@
 		dprintk(NDEBUG_MERGING, "merged %d buffers from %p, new length %08x\n",
 			   cnt, cmd->SCp.ptr, cmd->SCp.this_residual);
 #endif
+#endif /* !defined(CONFIG_SUN3) */
 }
 
 /*
@@ -1041,12 +1046,10 @@
 			     prev = NULL; tmp; prev = tmp, tmp = NEXT(tmp)) {
 				u8 lun = tmp->device->lun;
 
-#if (NDEBUG & NDEBUG_LISTS)
-				if (prev != tmp)
-					printk("MAIN tmp=%p   target=%d   busy=%d lun=%llu\n",
-					       tmp, tmp->device->id, hostdata->busy[tmp->device->id],
-					       lun);
-#endif
+				dprintk(NDEBUG_LISTS,
+				        "MAIN tmp=%p target=%d busy=%d lun=%d\n",
+				        tmp, scmd_id(tmp), hostdata->busy[scmd_id(tmp)],
+				        lun);
 				/*  When we find one, remove it from the issue queue. */
 				/* ++guenther: possible race with Falcon locking */
 				if (
@@ -1155,9 +1158,11 @@
 static void NCR5380_dma_complete(struct Scsi_Host *instance)
 {
 	SETUP_HOSTDATA(instance);
-	int transfered, saved_data = 0, overrun = 0, cnt, toPIO;
-	unsigned char **data, p;
+	int transfered;
+	unsigned char **data;
 	volatile int *count;
+	int saved_data = 0, overrun = 0;
+	unsigned char p;
 
 	if (!hostdata->connected) {
 		printk(KERN_WARNING "scsi%d: received end of DMA interrupt with "
@@ -1183,6 +1188,24 @@
 		   HOSTNO, NCR5380_read(BUS_AND_STATUS_REG),
 		   NCR5380_read(STATUS_REG));
 
+#if defined(CONFIG_SUN3)
+	if ((sun3scsi_dma_finish(rq_data_dir(hostdata->connected->request)))) {
+		pr_err("scsi%d: overrun in UDC counter -- not prepared to deal with this!\n",
+		       instance->host_no);
+		BUG();
+	}
+
+	/* make sure we're not stuck in a data phase */
+	if ((NCR5380_read(BUS_AND_STATUS_REG) & (BASR_PHASE_MATCH | BASR_ACK)) ==
+	    (BASR_PHASE_MATCH | BASR_ACK)) {
+		pr_err("scsi%d: BASR %02x\n", instance->host_no,
+		       NCR5380_read(BUS_AND_STATUS_REG));
+		pr_err("scsi%d: bus stuck in data phase -- probably a single byte overrun!\n",
+		       instance->host_no);
+		BUG();
+	}
+#endif
+
 	(void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
 	NCR5380_write(MODE_REG, MR_BASE);
 	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
@@ -1196,6 +1219,8 @@
 	*count -= transfered;
 
 	if (hostdata->read_overruns) {
+		int cnt, toPIO;
+
 		if ((NCR5380_read(STATUS_REG) & PHASE_MASK) == p && (p & SR_IO)) {
 			cnt = toPIO = hostdata->read_overruns;
 			if (overrun) {
@@ -1275,11 +1300,14 @@
 			{
 /* MS: Ignore unknown phase mismatch interrupts (caused by EOP interrupt) */
 				if (basr & BASR_PHASE_MATCH)
-					printk(KERN_NOTICE "scsi%d: unknown interrupt, "
+					dprintk(NDEBUG_INTR, "scsi%d: unknown interrupt, "
 					       "BASR 0x%x, MR 0x%x, SR 0x%x\n",
 					       HOSTNO, basr, NCR5380_read(MODE_REG),
 					       NCR5380_read(STATUS_REG));
 				(void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
+#ifdef SUN3_SCSI_VME
+				dregs->csr |= CSR_DMA_ENABLE;
+#endif
 			}
 		} /* if !(SELECTION || PARITY) */
 		handled = 1;
@@ -1288,6 +1316,9 @@
 		       "BASR 0x%X, MR 0x%X, SR 0x%x\n", HOSTNO, basr,
 		       NCR5380_read(MODE_REG), NCR5380_read(STATUS_REG));
 		(void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
+#ifdef SUN3_SCSI_VME
+		dregs->csr |= CSR_DMA_ENABLE;
+#endif
 	}
 
 	if (!done) {
@@ -1620,6 +1651,9 @@
 #ifndef SUPPORT_TAGS
 	hostdata->busy[cmd->device->id] |= (1 << cmd->device->lun);
 #endif
+#ifdef SUN3_SCSI_VME
+	dregs->csr |= CSR_INTR;
+#endif
 
 	initialize_SCp(cmd);
 
@@ -1843,9 +1877,54 @@
 	SETUP_HOSTDATA(instance);
 	register int c = *count;
 	register unsigned char p = *phase;
+	unsigned long flags;
+
+#if defined(CONFIG_SUN3)
+	/* sanity check */
+	if (!sun3_dma_setup_done) {
+		pr_err("scsi%d: transfer_dma without setup!\n",
+		       instance->host_no);
+		BUG();
+	}
+	hostdata->dma_len = c;
+
+	dprintk(NDEBUG_DMA, "scsi%d: initializing DMA for %s, %d bytes %s %p\n",
+		instance->host_no, (p & SR_IO) ? "reading" : "writing",
+		c, (p & SR_IO) ? "to" : "from", *data);
+
+	/* netbsd turns off ints here, why not be safe and do it too */
+	local_irq_save(flags);
+
+	/* send start chain */
+	sun3scsi_dma_start(c, *data);
+
+	if (p & SR_IO) {
+		NCR5380_write(TARGET_COMMAND_REG, 1);
+		NCR5380_read(RESET_PARITY_INTERRUPT_REG);
+		NCR5380_write(INITIATOR_COMMAND_REG, 0);
+		NCR5380_write(MODE_REG,
+			      (NCR5380_read(MODE_REG) | MR_DMA_MODE | MR_ENABLE_EOP_INTR));
+		NCR5380_write(START_DMA_INITIATOR_RECEIVE_REG, 0);
+	} else {
+		NCR5380_write(TARGET_COMMAND_REG, 0);
+		NCR5380_read(RESET_PARITY_INTERRUPT_REG);
+		NCR5380_write(INITIATOR_COMMAND_REG, ICR_ASSERT_DATA);
+		NCR5380_write(MODE_REG,
+			      (NCR5380_read(MODE_REG) | MR_DMA_MODE | MR_ENABLE_EOP_INTR));
+		NCR5380_write(START_DMA_SEND_REG, 0);
+	}
+
+#ifdef SUN3_SCSI_VME
+	dregs->csr |= CSR_DMA_ENABLE;
+#endif
+
+	local_irq_restore(flags);
+
+	sun3_dma_active = 1;
+
+#else /* !defined(CONFIG_SUN3) */
 	register unsigned char *d = *data;
 	unsigned char tmp;
-	unsigned long flags;
 
 	if ((tmp = (NCR5380_read(STATUS_REG) & PHASE_MASK)) != p) {
 		*phase = tmp;
@@ -1893,6 +1972,8 @@
 			NCR5380_dma_write_setup(instance, d, c);
 		local_irq_restore(flags);
 	}
+#endif /* !defined(CONFIG_SUN3) */
+
 	return 0;
 }
 #endif /* defined(REAL_DMA) */
@@ -1928,6 +2009,10 @@
 	unsigned char phase, tmp, extended_msg[10], old_phase = 0xff;
 	struct scsi_cmnd *cmd = (struct scsi_cmnd *) hostdata->connected;
 
+#ifdef SUN3_SCSI_VME
+	dregs->csr |= CSR_INTR;
+#endif
+
 	while (1) {
 		tmp = NCR5380_read(STATUS_REG);
 		/* We only have a valid SCSI phase when REQ is asserted */
@@ -1937,6 +2022,33 @@
 				old_phase = phase;
 				NCR5380_dprint_phase(NDEBUG_INFORMATION, instance);
 			}
+#if defined(CONFIG_SUN3)
+			if (phase == PHASE_CMDOUT) {
+#if defined(REAL_DMA)
+				void *d;
+				unsigned long count;
+
+				if (!cmd->SCp.this_residual && cmd->SCp.buffers_residual) {
+					count = cmd->SCp.buffer->length;
+					d = sg_virt(cmd->SCp.buffer);
+				} else {
+					count = cmd->SCp.this_residual;
+					d = cmd->SCp.ptr;
+				}
+				/* this command setup for dma yet? */
+				if ((count >= DMA_MIN_SIZE) && (sun3_dma_setup_done != cmd)) {
+					if (cmd->request->cmd_type == REQ_TYPE_FS) {
+						sun3scsi_dma_setup(d, count,
+						                   rq_data_dir(cmd->request));
+						sun3_dma_setup_done = cmd;
+					}
+				}
+#endif
+#ifdef SUN3_SCSI_VME
+				dregs->csr |= CSR_INTR;
+#endif
+			}
+#endif /* CONFIG_SUN3 */
 
 			if (sink && (phase != PHASE_MSGOUT)) {
 				NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(tmp));
@@ -1998,8 +2110,11 @@
 				 */
 
 #if defined(REAL_DMA)
-				if (!cmd->device->borken &&
-				    (transfersize = NCR5380_dma_xfer_len(instance,cmd,phase)) > 31) {
+				if (
+#if !defined(CONFIG_SUN3)
+				    !cmd->device->borken &&
+#endif
+				    (transfersize = NCR5380_dma_xfer_len(instance, cmd, phase)) >= DMA_MIN_SIZE) {
 					len = transfersize;
 					cmd->SCp.phase = phase;
 					if (NCR5380_transfer_dma(instance, &phase,
@@ -2036,6 +2151,11 @@
 					NCR5380_transfer_pio(instance, &phase,
 							     (int *)&cmd->SCp.this_residual,
 							     (unsigned char **)&cmd->SCp.ptr);
+#if defined(CONFIG_SUN3) && defined(REAL_DMA)
+				/* if we had intended to dma that command clear it */
+				if (sun3_dma_setup_done == cmd)
+					sun3_dma_setup_done = NULL;
+#endif
 				break;
 			case PHASE_MSGIN:
 				len = 1;
@@ -2241,6 +2361,9 @@
 					/* Wait for bus free to avoid nasty timeouts */
 					while ((NCR5380_read(STATUS_REG) & SR_BSY) && !hostdata->connected)
 						barrier();
+#ifdef SUN3_SCSI_VME
+					dregs->csr |= CSR_DMA_ENABLE;
+#endif
 					return;
 					/*
 					 * The SCSI data pointer is *IMPLICITLY* saved on a disconnect
@@ -2400,17 +2523,20 @@
  */
 
 
+/* it might eventually prove necessary to do a dma setup on
+   reselection, but it doesn't seem to be needed now -- sam */
+
 static void NCR5380_reselect(struct Scsi_Host *instance)
 {
 	SETUP_HOSTDATA(instance);
 	unsigned char target_mask;
-	unsigned char lun, phase;
-	int len;
+	unsigned char lun;
 #ifdef SUPPORT_TAGS
 	unsigned char tag;
 #endif
 	unsigned char msg[3];
-	unsigned char *data;
+	int __maybe_unused len;
+	unsigned char __maybe_unused *data, __maybe_unused phase;
 	struct scsi_cmnd *tmp = NULL, *prev;
 
 	/*
@@ -2447,10 +2573,18 @@
 	while (!(NCR5380_read(STATUS_REG) & SR_REQ))
 		;
 
+#if defined(CONFIG_SUN3) && defined(REAL_DMA)
+	/* acknowledge toggle to MSGIN */
+	NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(PHASE_MSGIN));
+
+	/* peek at the byte without really hitting the bus */
+	msg[0] = NCR5380_read(CURRENT_SCSI_DATA_REG);
+#else
 	len = 1;
 	data = msg;
 	phase = PHASE_MSGIN;
 	NCR5380_transfer_pio(instance, &phase, &len, &data);
+#endif
 
 	if (!(msg[0] & 0x80)) {
 		printk(KERN_DEBUG "scsi%d: expecting IDENTIFY message, got ", HOSTNO);
@@ -2460,7 +2594,7 @@
 	}
 	lun = (msg[0] & 0x07);
 
-#ifdef SUPPORT_TAGS
+#if defined(SUPPORT_TAGS) && !defined(CONFIG_SUN3)
 	/* 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.
@@ -2522,9 +2656,51 @@
 		return;
 	}
 
+#if defined(CONFIG_SUN3) && defined(REAL_DMA)
+	/* engage dma setup for the command we just saw */
+	{
+		void *d;
+		unsigned long count;
+
+		if (!tmp->SCp.this_residual && tmp->SCp.buffers_residual) {
+			count = tmp->SCp.buffer->length;
+			d = sg_virt(tmp->SCp.buffer);
+		} else {
+			count = tmp->SCp.this_residual;
+			d = tmp->SCp.ptr;
+		}
+		/* setup this command for dma if not already */
+		if ((count >= DMA_MIN_SIZE) && (sun3_dma_setup_done != tmp)) {
+			sun3scsi_dma_setup(d, count, rq_data_dir(tmp->request));
+			sun3_dma_setup_done = tmp;
+		}
+	}
+
+	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ACK);
+#endif
+
 	/* Accept message by clearing ACK */
 	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
 
+#if defined(SUPPORT_TAGS) && defined(CONFIG_SUN3)
+	/* 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
+
 	hostdata->connected = tmp;
 	dprintk(NDEBUG_RESELECTION, "scsi%d: nexus established, target = %d, lun = %llu, tag = %d\n",
 		   HOSTNO, tmp->device->id, tmp->device->lun, tmp->tag);
diff --git a/drivers/scsi/atari_scsi.c b/drivers/scsi/atari_scsi.c
index 0451121..f0da0c8 100644
--- a/drivers/scsi/atari_scsi.c
+++ b/drivers/scsi/atari_scsi.c
@@ -89,6 +89,7 @@
 #define REAL_DMA
 #define SUPPORT_TAGS
 #define MAX_TAGS                        32
+#define DMA_MIN_SIZE                    32
 
 #define NCR5380_implementation_fields   /* none */