@@ -1318,17 +1318,19 @@ static void NCR5380_transfer_pio(struct Scsi_Host *instance,
dsprintk(NDEBUG_HANDSHAKE, instance, "REQ negated, handshake complete\n");
-/*
- * We have several special cases to consider during REQ/ACK handshaking :
- * 1. We were in MSGOUT phase, and we are on the last byte of the
- * message. ATN must be dropped as ACK is dropped.
- *
- * 2. We are in a MSGIN phase, and we are on the last byte of the
- * message. We must exit with ACK asserted, so that the calling
- * code may raise ATN before dropping ACK to reject the message.
- *
- * 3. ACK and ATN are clear and the target may proceed as normal.
- */
+ /*
+ * We have several special cases to consider during REQ/ACK
+ * handshaking:
+ *
+ * 1. We were in MSGOUT phase, and we are on the last byte of
+ * the message. ATN must be dropped as ACK is dropped.
+ *
+ * 2. We are in MSGIN phase, and we are on the last byte of the
+ * message. We must exit with ACK asserted, so that the calling
+ * code may raise ATN before dropping ACK to reject the message.
+ *
+ * 3. ACK and ATN are clear & the target may proceed as normal.
+ */
if (!(p == PHASE_MSGIN && c == 1)) {
if (p == PHASE_MSGOUT && c > 1)
NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
@@ -1559,39 +1561,41 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance,
/* The result is zero iff pseudo DMA send/receive was completed. */
hostdata->dma_len = c;
-/*
- * A note regarding the DMA errata workarounds for early NMOS silicon.
- *
- * For DMA sends, we want to wait until the last byte has been
- * transferred out over the bus before we turn off DMA mode. Alas, there
- * seems to be no terribly good way of doing this on a 5380 under all
- * conditions. For non-scatter-gather operations, we can wait until REQ
- * and ACK both go false, or until a phase mismatch occurs. Gather-sends
- * are nastier, since the device will be expecting more data than we
- * are prepared to send it, and REQ will remain asserted. On a 53C8[01] we
- * could test Last Byte Sent to assure transfer (I imagine this is precisely
- * why this signal was added to the newer chips) but on the older 538[01]
- * this signal does not exist. The workaround for this lack is a watchdog;
- * we bail out of the wait-loop after a modest amount of wait-time if
- * the usual exit conditions are not met. Not a terribly clean or
- * correct solution :-%
- *
- * DMA receive is equally tricky due to a nasty characteristic of the NCR5380.
- * If the chip is in DMA receive mode, it will respond to a target's
- * REQ by latching the SCSI data into the INPUT DATA register and asserting
- * ACK, even if it has _already_ been notified by the DMA controller that
- * the current DMA transfer has completed! If the NCR5380 is then taken
- * out of DMA mode, this already-acknowledged byte is lost. This is
- * not a problem for "one DMA transfer per READ command", because
- * the situation will never arise... either all of the data is DMA'ed
- * properly, or the target switches to MESSAGE IN phase to signal a
- * disconnection (either operation bringing the DMA to a clean halt).
- * However, in order to handle scatter-receive, we must work around the
- * problem. The chosen fix is to DMA fewer bytes, then check for the
- * condition before taking the NCR5380 out of DMA mode. One or two extra
- * bytes are transferred via PIO as necessary to fill out the original
- * request.
- */
+ /*
+ * A note regarding the DMA errata workarounds for early NMOS silicon.
+ *
+ * For DMA sends, we want to wait until the last byte has been
+ * transferred out over the bus before we turn off DMA mode. Alas, there
+ * seems to be no terribly good way of doing this on a 5380 under all
+ * conditions. For non-scatter-gather operations, we can wait until REQ
+ * and ACK both go false, or until a phase mismatch occurs. Gather-sends
+ * are nastier, since the device will be expecting more data than we
+ * are prepared to send it, and REQ will remain asserted. On a 53C8[01]
+ * we could test Last Byte Sent to assure transfer (I imagine this is
+ * precisely why this signal was added to the newer chips) but on the
+ * older 538[01] this signal does not exist. The workaround for this
+ * lack is a watchdog; we bail out of the wait-loop after a modest
+ * amount of wait-time if the usual exit conditions are not met.
+ * Not a terribly clean or correct solution :-%
+ *
+ * DMA receive is equally tricky due to a nasty characteristic of the
+ * NCR5380. If the chip is in DMA receive mode, it will respond to a
+ * target's REQ by latching the SCSI data into the INPUT DATA register
+ * and asserting ACK, even if it has _already_ been notified by the
+ * DMA controller that the current DMA transfer has completed! If the
+ * NCR5380 is then taken out of DMA mode, this already-acknowledged
+ * byte is lost.
+ *
+ * This is not a problem for "one DMA transfer per READ
+ * command", because the situation will never arise... either all of
+ * the data is DMA'ed properly, or the target switches to MESSAGE IN
+ * phase to signal a disconnection (either operation bringing the DMA
+ * to a clean halt). However, in order to handle scatter-receive, we
+ * must work around the problem. The chosen fix is to DMA fewer bytes,
+ * then check for the condition before taking the NCR5380 out of DMA
+ * mode. One or two extra bytes are transferred via PIO as necessary
+ * to fill out the original request.
+ */
if ((hostdata->flags & FLAG_DMA_FIXUP) &&
(NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH)) {
@@ -3,10 +3,10 @@
* NCR 5380 defines
*
* Copyright 1993, Drew Eckhardt
- * Visionary Computing
- * (Unix consulting and custom programming)
- * drew@colorado.edu
- * +1 (303) 666-5836
+ * Visionary Computing
+ * (Unix consulting and custom programming)
+ * drew@colorado.edu
+ * +1 (303) 666-5836
*
* For more information, please consult
*
@@ -78,7 +78,7 @@
#define ICR_DIFF_ENABLE 0x20 /* wo Set to enable diff. drivers */
#define ICR_ASSERT_ACK 0x10 /* rw ini Set to assert ACK */
#define ICR_ASSERT_BSY 0x08 /* rw Set to assert BSY */
-#define ICR_ASSERT_SEL 0x04 /* rw Set to assert SEL */
+#define ICR_ASSERT_SEL 0x04 /* rw Set to assert SEL */
#define ICR_ASSERT_ATN 0x02 /* rw Set to assert ATN */
#define ICR_ASSERT_DATA 0x01 /* rw SCSI_DATA_REG is asserted */
@@ -135,7 +135,7 @@
#define BASR_IRQ 0x10 /* ro mirror of IRQ pin */
#define BASR_PHASE_MATCH 0x08 /* ro Set when MSG CD IO match TCR */
#define BASR_BUSY_ERROR 0x04 /* ro Unexpected change to inactive state */
-#define BASR_ATN 0x02 /* ro BUS status */
+#define BASR_ATN 0x02 /* ro BUS status */
#define BASR_ACK 0x01 /* ro BUS status */
/* Write any value to this register to start a DMA send */
@@ -170,7 +170,7 @@
#define CSR_BASE CSR_53C80_INTR
/* Note : PHASE_* macros are based on the values of the STATUS register */
-#define PHASE_MASK (SR_MSG | SR_CD | SR_IO)
+#define PHASE_MASK (SR_MSG | SR_CD | SR_IO)
#define PHASE_DATAOUT 0
#define PHASE_DATAIN SR_IO
@@ -304,7 +304,7 @@ static int sun3scsi_dma_setup(struct NCR5380_hostdata *hostdata,
sun3_udc_write(UDC_INT_ENABLE, UDC_CSR);
#endif
- return count;
+ return count;
}
Tidy up a few indentation annoyances. No functional change. Signed-off-by: Finn Thain <fthain@linux-m68k.org> --- drivers/scsi/NCR5380.c | 92 +++++++++++++++++++++------------------- drivers/scsi/NCR5380.h | 14 +++--- drivers/scsi/sun3_scsi.c | 2 +- 3 files changed, 56 insertions(+), 52 deletions(-)