Checkpoint of work-in-progress DMA support for oaic(4). Not working yet,

probably due to incorrect programming of the system board ``Diagnostic Control
Register'', for which I do not have documentation yet; commited so as not to
lose this work, since the machine I was testing on has apparently commited
suicide and will no longer POST.

2 files changed, 47 insertions, 2 deletions

diff --git a/sys/dev/ic/aic6250.c b/sys/dev/ic/aic6250.c
index c0c4f5c88a2..67a2bd02e48 100644
--- a/sys/dev/ic/aic6250.c
+++ b/sys/dev/ic/aic6250.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: aic6250.c,v 1.1 2013/10/15 01:41:45 miod Exp $	*/
+/*	$OpenBSD: aic6250.c,v 1.2 2013/10/23 10:07:14 miod Exp $	*/
 
 /*
  * Copyright (c) 2010, 2013 Miodrag Vallat.
@@ -100,6 +100,9 @@
 
 #define	AIC_ABORT_TIMEOUT	2000	/* time to wait for abort */
 
+/* threshold length for DMA transfer */
+#define	AIC_MIN_DMA_LEN		32
+
 /* End of customizable parameters */
 
 #include <sys/types.h>
@@ -1376,11 +1379,20 @@ aic6250_intr(void *arg)
 
 loop:
 	sr0 = (*sc->sc_read)(sc, AIC_STATUS_REG0);
+
 	/*
 	 * First check for abnormal conditions, such as reset.
 	 */
 	AIC_MISC(("sr0:0x%02x ", sr0));
 
+	/*
+	 * Check for the end of a DMA operation before doing anything else...
+	 */
+	if ((sc->sc_flags & AIC_DOINGDMA) != 0 &&
+	    (sr0 & AIC_SR1_CMD_DONE) != 0) {
+		(*sc->sc_dma_done)(sc);
+	}
+
 	if ((sr0 & AIC_SR0_SCSI_RST_OCCURED) != 0) {
 		printf("%s: SCSI bus reset\n", sc->sc_dev.dv_xname);
 		while (((*sc->sc_read)(sc, AIC_STATUS_REG1) &
@@ -1618,6 +1630,13 @@ loop:
 		}
 	}
 
+	/*
+	 * Do not change phase (yet) if we have a pending DMA operation.
+	 */
+	if ((sc->sc_flags & AIC_DOINGDMA) != 0) {
+		goto out;
+	}
+
 dophase:
 	if ((sr0 & AIC_SR0_SCSI_REQ_ON) == 0) {
 		/* Wait for AIC_SR0_SCSI_REQ_ON. */
@@ -1665,6 +1684,17 @@ dophase:
 		if (sc->sc_state != AIC_CONNECTED)
 			break;
 		AIC_MISC(("dataout dleft=%lu ", (u_long)sc->sc_dleft));
+		if (sc->sc_dma_start != NULL &&
+		    sc->sc_dleft > AIC_MIN_DMA_LEN) {
+			AIC_ASSERT(sc->sc_nexus != NULL);
+			acb = sc->sc_nexus;
+			if ((acb->xs->flags & SCSI_POLL) == 0 &&
+			    (*sc->sc_dma_start)
+			    (sc, sc->sc_dp, sc->sc_dleft, 0) == 0) {
+				sc->sc_prevphase = PH_DATAOUT;
+				goto out;
+			}
+		}
 		n = aic6250_dataout_pio(sc, sc->sc_dp, sc->sc_dleft, PH_DATAOUT);
 		sc->sc_dp += n;
 		sc->sc_dleft -= n;
@@ -1675,6 +1705,17 @@ dophase:
 		if (sc->sc_state != AIC_CONNECTED)
 			break;
 		AIC_MISC(("datain %lu ", (u_long)sc->sc_dleft));
+		if (sc->sc_dma_start != NULL &&
+		    sc->sc_dleft > AIC_MIN_DMA_LEN) {
+			AIC_ASSERT(sc->sc_nexus != NULL);
+			acb = sc->sc_nexus;
+			if ((acb->xs->flags & SCSI_POLL) == 0 &&
+			    (*sc->sc_dma_start)
+			    (sc, sc->sc_dp, sc->sc_dleft, 1) == 0) {
+				sc->sc_prevphase = PH_DATAIN;
+				goto out;
+			}
+		}
 		n = aic6250_datain_pio(sc, sc->sc_dp, sc->sc_dleft, PH_DATAIN);
 		sc->sc_dp += n;
 		sc->sc_dleft -= n;
diff --git a/sys/dev/ic/aic6250var.h b/sys/dev/ic/aic6250var.h
index 713e165ce0f..f5e49a24015 100644
--- a/sys/dev/ic/aic6250var.h
+++ b/sys/dev/ic/aic6250var.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: aic6250var.h,v 1.1 2013/10/15 01:41:46 miod Exp $	*/
+/*	$OpenBSD: aic6250var.h,v 1.2 2013/10/23 10:07:14 miod Exp $	*/
 
 /*
  * Copyright (c) 2010, 2013 Miodrag Vallat.
@@ -190,6 +190,10 @@ struct aic6250_softc {
 	int	sc_freq;		/* Clock frequency in MHz */
 	int	sc_minsync;		/* Minimum sync period / 4 */
 	int	sc_maxsync;		/* Maximum sync period / 4 */
+
+	/* DMA function set from MD code */
+	int	(*sc_dma_start)(struct aic6250_softc *, void *, size_t, int);
+	int	(*sc_dma_done)(struct aic6250_softc *);
 };
 
 #if AIC_DEBUG