[PATCH v7 2/6] g_NCR5380: End PDMA transfer correctly on target disconnection

[PATCH v7 2/6] g_NCR5380: End PDMA transfer correctly on target disconnection

[Finn Thain]

From: Ondrej Zary <linux@rainbow-software.org>

When an IRQ arrives during PDMA transfer, pread() and pwrite() return
without waiting for the 53C80 registers to be ready and this ends up
messing up the chip state. This was observed with SONY CDU-55S which is
slow enough to disconnect during 4096-byte reads.

IRQ during PDMA is not an error so don't return -1. Instead, store the
remaining byte count for use by NCR5380_dma_residual().

[Poll for the BASR_END_DMA_TRANSFER condition rather than remove the
error message -- F.T.]

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
---
 drivers/scsi/g_NCR5380.c | 48 +++++++++++++++++++++++++++++++-----------------
 1 file changed, 31 insertions(+), 17 deletions(-)

diff --git a/drivers/scsi/g_NCR5380.c b/drivers/scsi/g_NCR5380.c
index 14ef4e8c4713..911a4300ea51 100644
--- a/drivers/scsi/g_NCR5380.c
+++ b/drivers/scsi/g_NCR5380.c
@@ -44,12 +44,13 @@
 	int c400_ctl_status; \
 	int c400_blk_cnt; \
 	int c400_host_buf; \
-	int io_width
+	int io_width; \
+	int pdma_residual
 
 #define NCR5380_dma_xfer_len            generic_NCR5380_dma_xfer_len
 #define NCR5380_dma_recv_setup          generic_NCR5380_pread
 #define NCR5380_dma_send_setup          generic_NCR5380_pwrite
-#define NCR5380_dma_residual            NCR5380_dma_residual_none
+#define NCR5380_dma_residual            generic_NCR5380_dma_residual
 
 #define NCR5380_intr                    generic_NCR5380_intr
 #define NCR5380_queue_command           generic_NCR5380_queue_command
@@ -500,10 +501,8 @@ static inline int generic_NCR5380_pread(struct NCR5380_hostdata *hostdata,
 	while (1) {
 		if (NCR5380_read(hostdata->c400_blk_cnt) == 0)
 			break;
-		if (NCR5380_read(hostdata->c400_ctl_status) & CSR_GATED_53C80_IRQ) {
-			printk(KERN_ERR "53C400r: Got 53C80_IRQ start=%d, blocks=%d\n", start, blocks);
-			return -1;
-		}
+		if (NCR5380_read(hostdata->c400_ctl_status) & CSR_GATED_53C80_IRQ)
+			goto out_wait;
 		while (NCR5380_read(hostdata->c400_ctl_status) & CSR_HOST_BUF_NOT_RDY)
 			; /* FIXME - no timeout */
 
@@ -542,13 +541,19 @@ static inline int generic_NCR5380_pread(struct NCR5380_hostdata *hostdata,
 	if (!(NCR5380_read(hostdata->c400_ctl_status) & CSR_GATED_53C80_IRQ))
 		printk("53C400r: no 53C80 gated irq after transfer");
 
+out_wait:
+	hostdata->pdma_residual = len - start;
+
 	/* wait for 53C80 registers to be available */
 	while (!(NCR5380_read(hostdata->c400_ctl_status) & CSR_53C80_REG))
 		;
 
-	if (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_END_DMA_TRANSFER))
-		printk(KERN_ERR "53C400r: no end dma signal\n");
-		
+	if (NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG,
+	                          BASR_END_DMA_TRANSFER, BASR_END_DMA_TRANSFER,
+	                          HZ / 64) < 0)
+		scmd_printk(KERN_ERR, hostdata->connected, "%s: End of DMA timeout (%d)\n",
+		            __func__, hostdata->pdma_residual);
+
 	return 0;
 }
 
@@ -571,10 +576,8 @@ static inline int generic_NCR5380_pwrite(struct NCR5380_hostdata *hostdata,
 	NCR5380_write(hostdata->c400_ctl_status, CSR_BASE);
 	NCR5380_write(hostdata->c400_blk_cnt, blocks);
 	while (1) {
-		if (NCR5380_read(hostdata->c400_ctl_status) & CSR_GATED_53C80_IRQ) {
-			printk(KERN_ERR "53C400w: Got 53C80_IRQ start=%d, blocks=%d\n", start, blocks);
-			return -1;
-		}
+		if (NCR5380_read(hostdata->c400_ctl_status) & CSR_GATED_53C80_IRQ)
+			goto out_wait;
 
 		if (NCR5380_read(hostdata->c400_blk_cnt) == 0)
 			break;
@@ -612,18 +615,24 @@ static inline int generic_NCR5380_pwrite(struct NCR5380_hostdata *hostdata,
 		blocks--;
 	}
 
+out_wait:
+	hostdata->pdma_residual = len - start;
+
 	/* wait for 53C80 registers to be available */
 	while (!(NCR5380_read(hostdata->c400_ctl_status) & CSR_53C80_REG)) {
 		udelay(4); /* DTC436 chip hangs without this */
 		/* FIXME - no timeout */
 	}
 
-	if (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_END_DMA_TRANSFER)) {
-		printk(KERN_ERR "53C400w: no end dma signal\n");
-	}
-
 	while (!(NCR5380_read(TARGET_COMMAND_REG) & TCR_LAST_BYTE_SENT))
 		; 	// TIMEOUT
+
+	if (NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG,
+	                          BASR_END_DMA_TRANSFER, BASR_END_DMA_TRANSFER,
+	                          HZ / 64) < 0)
+		scmd_printk(KERN_ERR, hostdata->connected, "%s: End of DMA timeout (%d)\n",
+		            __func__, hostdata->pdma_residual);
+
 	return 0;
 }
 
@@ -642,6 +651,11 @@ static int generic_NCR5380_dma_xfer_len(struct NCR5380_hostdata *hostdata,
 	return min(transfersize, DMA_MAX_SIZE);
 }
 
+static int generic_NCR5380_dma_residual(struct NCR5380_hostdata *hostdata)
+{
+	return hostdata->pdma_residual;
+}
+
 /*
  *	Include the NCR5380 core code that we build our driver around	
  */
-- 
2.13.0

[PATCH v7 1/6] g_NCR5380: Fix PDMA transfer size

[Finn Thain]

From: Ondrej Zary <linux@rainbow-software.org>

generic_NCR5380_dma_xfer_len() incorrectly uses cmd->transfersize
which causes rescan-scsi-bus and CD-ROM access to hang the system.
Use cmd->SCp.this_residual instead, like other NCR5380 drivers.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
---
 drivers/scsi/g_NCR5380.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/g_NCR5380.c b/drivers/scsi/g_NCR5380.c
index 67c8dac321ad..14ef4e8c4713 100644
--- a/drivers/scsi/g_NCR5380.c
+++ b/drivers/scsi/g_NCR5380.c
@@ -76,6 +76,7 @@
 #define IRQ_AUTO 254
 
 #define MAX_CARDS 8
+#define DMA_MAX_SIZE 32768
 
 /* old-style parameters for compatibility */
 static int ncr_irq = -1;
@@ -629,23 +630,16 @@ static inline int generic_NCR5380_pwrite(struct NCR5380_hostdata *hostdata,
 static int generic_NCR5380_dma_xfer_len(struct NCR5380_hostdata *hostdata,
                                         struct scsi_cmnd *cmd)
 {
-	int transfersize = cmd->transfersize;
+	int transfersize = cmd->SCp.this_residual;
 
 	if (hostdata->flags & FLAG_NO_PSEUDO_DMA)
 		return 0;
 
-	/* Limit transfers to 32K, for xx400 & xx406
-	 * pseudoDMA that transfers in 128 bytes blocks.
-	 */
-	if (transfersize > 32 * 1024 && cmd->SCp.this_residual &&
-	    !(cmd->SCp.this_residual % transfersize))
-		transfersize = 32 * 1024;
-
 	/* 53C400 datasheet: non-modulo-128-byte transfers should use PIO */
 	if (transfersize % 128)
 		transfersize = 0;
 
-	return transfersize;
+	return min(transfersize, DMA_MAX_SIZE);
 }
 
 /*
-- 
2.13.0

[PATCH v7 0/6] g_NCR5380: PDMA fixes and cleanup

[Finn Thain]

Ondrej, would you please test this new series?

Changed since v1:
- PDMA transfer residual is calculated earlier.
- End of DMA flag check is now polled (if there is any residual).

Changed since v2:
- Bail out of transfer loops when Gated IRQ gets asserted.
- Make udelay conditional on board type.
- Drop sg_tablesize patch due to performance regression.

Changed since v3:
- Add Ondrej's workaround for corrupt WRITE commands on DTC boards.
- Reset the 53c400 logic after any short PDMA transfer.
- Don't fail the transfer if the 53c400 logic got a reset.

Changed since v4:
- Bail out of transfer loops when Gated IRQ gets asserted. (Again.)
- Always call wait_for_53c80_registers() at end of transfer.
- Drain chip buffers after PDMA receive is interrupted.
- Rework residual calculation.
- Add new patch to correct DMA terminology.

Changed since v5:
- Rework residual calculation to account for on-chip buffer swap.
- Attempt to retain the disconnect/IRQ detection in the DTC436 workaround.
- Move all DTC436 workarounds to final patch.

Changed since v6:
- Fix residual calculation for the buffer timeout case.
- Iterate after sending final 128 bytes to check for buffer timeout.
- Don't log the residual value when it is known to be zero.


Finn Thain (2):
  g_NCR5380: Cleanup comments and whitespace
  g_NCR5380: Use unambiguous terminology for PDMA send and receive

Ondrej Zary (4):
  g_NCR5380: Fix PDMA transfer size
  g_NCR5380: End PDMA transfer correctly on target disconnection
  g_NCR5380: Re-work PDMA loops
  g_NCR5380: Two DTC436 PDMA workarounds

 drivers/scsi/g_NCR5380.c | 277 ++++++++++++++++++++++++++---------------------
 1 file changed, 155 insertions(+), 122 deletions(-)

-- 
2.13.0

[PATCH v7 4/6] g_NCR5380: Use unambiguous terminology for PDMA send and receive

[Finn Thain]

The word "read" may be used to mean "DMA read operation" or
"SCSI READ command", though a READ command implies writing to memory.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
---
 drivers/scsi/g_NCR5380.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/g_NCR5380.c b/drivers/scsi/g_NCR5380.c
index dedaed2d16e4..33e1a480c903 100644
--- a/drivers/scsi/g_NCR5380.c
+++ b/drivers/scsi/g_NCR5380.c
@@ -48,8 +48,8 @@
 	int pdma_residual
 
 #define NCR5380_dma_xfer_len            generic_NCR5380_dma_xfer_len
-#define NCR5380_dma_recv_setup          generic_NCR5380_pread
-#define NCR5380_dma_send_setup          generic_NCR5380_pwrite
+#define NCR5380_dma_recv_setup          generic_NCR5380_precv
+#define NCR5380_dma_send_setup          generic_NCR5380_psend
 #define NCR5380_dma_residual            generic_NCR5380_dma_residual
 
 #define NCR5380_intr                    generic_NCR5380_intr
@@ -481,7 +481,7 @@ static void generic_NCR5380_release_resources(struct Scsi_Host *instance)
 }
 
 /**
- * generic_NCR5380_pread - pseudo DMA read
+ * generic_NCR5380_precv - pseudo DMA receive
  * @hostdata: scsi host private data
  * @dst: buffer to write into
  * @len: transfer size
@@ -489,7 +489,7 @@ static void generic_NCR5380_release_resources(struct Scsi_Host *instance)
  * Perform a pseudo DMA mode receive from a 53C400 or equivalent device.
  */
 
-static inline int generic_NCR5380_pread(struct NCR5380_hostdata *hostdata,
+static inline int generic_NCR5380_precv(struct NCR5380_hostdata *hostdata,
                                         unsigned char *dst, int len)
 {
 	int blocks = len / 128;
@@ -557,7 +557,7 @@ static inline int generic_NCR5380_pread(struct NCR5380_hostdata *hostdata,
 }
 
 /**
- * generic_NCR5380_pwrite - pseudo DMA write
+ * generic_NCR5380_psend - pseudo DMA send
  * @hostdata: scsi host private data
  * @src: buffer to read from
  * @len: transfer size
@@ -565,8 +565,8 @@ static inline int generic_NCR5380_pread(struct NCR5380_hostdata *hostdata,
  * Perform a pseudo DMA mode send to a 53C400 or equivalent device.
  */
 
-static inline int generic_NCR5380_pwrite(struct NCR5380_hostdata *hostdata,
-                                         unsigned char *src, int len)
+static inline int generic_NCR5380_psend(struct NCR5380_hostdata *hostdata,
+                                        unsigned char *src, int len)
 {
 	int blocks = len / 128;
 	int start = 0;
-- 
2.13.0

[PATCH v7 6/6] g_NCR5380: Two DTC436 PDMA workarounds

[Finn Thain]

From: Ondrej Zary <linux@rainbow-software.org>

Limit PDMA send to 512 B to avoid data corruption on DTC3181E. The
corruption is always the same: one byte missing at the beginning of
a 128 B block. It happens only with slow Quantum LPS 240 drive, not with
faster IBM DORS-32160. It's not clear what causes this. Documentation
for the DTC436 chip has not been made available.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
---
 drivers/scsi/g_NCR5380.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/g_NCR5380.c b/drivers/scsi/g_NCR5380.c
index af7aec394778..2bb934608373 100644
--- a/drivers/scsi/g_NCR5380.c
+++ b/drivers/scsi/g_NCR5380.c
@@ -45,7 +45,8 @@
 	int c400_blk_cnt; \
 	int c400_host_buf; \
 	int io_width; \
-	int pdma_residual
+	int pdma_residual; \
+	int board
 
 #define NCR5380_dma_xfer_len            generic_NCR5380_dma_xfer_len
 #define NCR5380_dma_recv_setup          generic_NCR5380_precv
@@ -316,6 +317,7 @@ static int generic_NCR5380_init_one(struct scsi_host_template *tpnt,
 	}
 	hostdata = shost_priv(instance);
 
+	hostdata->board = board;
 	hostdata->io = iomem;
 	hostdata->region_size = region_size;
 
@@ -492,6 +494,8 @@ static void wait_for_53c80_access(struct NCR5380_hostdata *hostdata)
 	int count = 10000;
 
 	do {
+		if (hostdata->board == BOARD_DTC3181E)
+			udelay(4); /* DTC436 chip hangs without this */
 		if (NCR5380_read(hostdata->c400_ctl_status) & CSR_53C80_REG)
 			return;
 	} while (--count > 0);
@@ -665,7 +669,12 @@ static int generic_NCR5380_dma_xfer_len(struct NCR5380_hostdata *hostdata,
 
 	/* 53C400 datasheet: non-modulo-128-byte transfers should use PIO */
 	if (transfersize % 128)
-		transfersize = 0;
+		return 0;
+
+	/* Limit PDMA send to 512 B to avoid random corruption on DTC3181E */
+	if (hostdata->board == BOARD_DTC3181E &&
+	    cmd->sc_data_direction == DMA_TO_DEVICE)
+		transfersize = min(cmd->SCp.this_residual, 512);
 
 	return min(transfersize, DMA_MAX_SIZE);
 }
-- 
2.13.0

[PATCH v7 5/6] g_NCR5380: Re-work PDMA loops

[Finn Thain]

From: Ondrej Zary <linux@rainbow-software.org>

The polling loops in pread() and pwrite() can easily become infinite
loops and hang the machine.

Merge the IRQ check into host buffer wait loop and add polling limit.

Also place a limit on polling for 53C80 registers accessibility.

[Use NCR5380_poll_politely2() for register polling. Rely on polling for
gated IRQ rather than polling for phase error, like the algorithm in the
53c400 datasheet. Move DTC436 workarounds into a separate patch.
Factor-out common code as wait_for_53c80_access(). Rework the residual
calculations. -- F.T.]

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
---
 drivers/scsi/g_NCR5380.c | 183 ++++++++++++++++++++++++++---------------------
 1 file changed, 102 insertions(+), 81 deletions(-)

diff --git a/drivers/scsi/g_NCR5380.c b/drivers/scsi/g_NCR5380.c
index 33e1a480c903..af7aec394778 100644
--- a/drivers/scsi/g_NCR5380.c
+++ b/drivers/scsi/g_NCR5380.c
@@ -480,6 +480,28 @@ static void generic_NCR5380_release_resources(struct Scsi_Host *instance)
 		release_mem_region(base, region_size);
 }
 
+/* wait_for_53c80_access - wait for 53C80 registers to become accessible
+ * @hostdata: scsi host private data
+ *
+ * The registers within the 53C80 logic block are inaccessible until
+ * bit 7 in the 53C400 control status register gets asserted.
+ */
+
+static void wait_for_53c80_access(struct NCR5380_hostdata *hostdata)
+{
+	int count = 10000;
+
+	do {
+		if (NCR5380_read(hostdata->c400_ctl_status) & CSR_53C80_REG)
+			return;
+	} while (--count > 0);
+
+	scmd_printk(KERN_ERR, hostdata->connected,
+	            "53c80 registers not accessible, device will be reset\n");
+	NCR5380_write(hostdata->c400_ctl_status, CSR_RESET);
+	NCR5380_write(hostdata->c400_ctl_status, CSR_BASE);
+}
+
 /**
  * generic_NCR5380_precv - pseudo DMA receive
  * @hostdata: scsi host private data
@@ -492,18 +514,27 @@ static void generic_NCR5380_release_resources(struct Scsi_Host *instance)
 static inline int generic_NCR5380_precv(struct NCR5380_hostdata *hostdata,
                                         unsigned char *dst, int len)
 {
-	int blocks = len / 128;
+	int residual;
 	int start = 0;
 
 	NCR5380_write(hostdata->c400_ctl_status, CSR_BASE | CSR_TRANS_DIR);
-	NCR5380_write(hostdata->c400_blk_cnt, blocks);
-	while (1) {
-		if (NCR5380_read(hostdata->c400_blk_cnt) == 0)
-			break;
-		if (NCR5380_read(hostdata->c400_ctl_status) & CSR_GATED_53C80_IRQ)
-			goto out_wait;
-		while (NCR5380_read(hostdata->c400_ctl_status) & CSR_HOST_BUF_NOT_RDY)
-			; /* FIXME - no timeout */
+	NCR5380_write(hostdata->c400_blk_cnt, len / 128);
+
+	do {
+		if (start == len - 128) {
+			/* Ignore End of DMA interrupt for the final buffer */
+			if (NCR5380_poll_politely(hostdata, hostdata->c400_ctl_status,
+			                          CSR_HOST_BUF_NOT_RDY, 0, HZ / 64) < 0)
+				break;
+		} else {
+			if (NCR5380_poll_politely2(hostdata, hostdata->c400_ctl_status,
+			                           CSR_HOST_BUF_NOT_RDY, 0,
+			                           hostdata->c400_ctl_status,
+			                           CSR_GATED_53C80_IRQ,
+			                           CSR_GATED_53C80_IRQ, HZ / 64) < 0 ||
+			    NCR5380_read(hostdata->c400_ctl_status) & CSR_HOST_BUF_NOT_RDY)
+				break;
+		}
 
 		if (hostdata->io_port && hostdata->io_width == 2)
 			insw(hostdata->io_port + hostdata->c400_host_buf,
@@ -514,44 +545,26 @@ static inline int generic_NCR5380_precv(struct NCR5380_hostdata *hostdata,
 		else
 			memcpy_fromio(dst + start,
 				hostdata->io + NCR53C400_host_buffer, 128);
-
 		start += 128;
-		blocks--;
-	}
+	} while (start < len);
 
-	if (blocks) {
-		while (NCR5380_read(hostdata->c400_ctl_status) & CSR_HOST_BUF_NOT_RDY)
-			; /* FIXME - no timeout */
-
-		if (hostdata->io_port && hostdata->io_width == 2)
-			insw(hostdata->io_port + hostdata->c400_host_buf,
-							dst + start, 64);
-		else if (hostdata->io_port)
-			insb(hostdata->io_port + hostdata->c400_host_buf,
-							dst + start, 128);
-		else
-			memcpy_fromio(dst + start,
-				hostdata->io + NCR53C400_host_buffer, 128);
+	residual = len - start;
 
-		start += 128;
-		blocks--;
+	if (residual != 0) {
+		/* 53c80 interrupt or transfer timeout. Reset 53c400 logic. */
+		NCR5380_write(hostdata->c400_ctl_status, CSR_RESET);
+		NCR5380_write(hostdata->c400_ctl_status, CSR_BASE);
 	}
+	wait_for_53c80_access(hostdata);
 
-	if (!(NCR5380_read(hostdata->c400_ctl_status) & CSR_GATED_53C80_IRQ))
-		printk("53C400r: no 53C80 gated irq after transfer");
-
-out_wait:
-	hostdata->pdma_residual = len - start;
+	if (residual == 0 && NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG,
+	                                           BASR_END_DMA_TRANSFER,
+	                                           BASR_END_DMA_TRANSFER,
+	                                           HZ / 64) < 0)
+		scmd_printk(KERN_ERR, hostdata->connected, "%s: End of DMA timeout\n",
+		            __func__);
 
-	/* wait for 53C80 registers to be available */
-	while (!(NCR5380_read(hostdata->c400_ctl_status) & CSR_53C80_REG))
-		;
-
-	if (NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG,
-	                          BASR_END_DMA_TRANSFER, BASR_END_DMA_TRANSFER,
-	                          HZ / 64) < 0)
-		scmd_printk(KERN_ERR, hostdata->connected, "%s: End of DMA timeout (%d)\n",
-		            __func__, hostdata->pdma_residual);
+	hostdata->pdma_residual = residual;
 
 	return 0;
 }
@@ -568,36 +581,39 @@ static inline int generic_NCR5380_precv(struct NCR5380_hostdata *hostdata,
 static inline int generic_NCR5380_psend(struct NCR5380_hostdata *hostdata,
                                         unsigned char *src, int len)
 {
-	int blocks = len / 128;
+	int residual;
 	int start = 0;
 
 	NCR5380_write(hostdata->c400_ctl_status, CSR_BASE);
-	NCR5380_write(hostdata->c400_blk_cnt, blocks);
-	while (1) {
-		if (NCR5380_read(hostdata->c400_ctl_status) & CSR_GATED_53C80_IRQ)
-			goto out_wait;
+	NCR5380_write(hostdata->c400_blk_cnt, len / 128);
+
+	do {
+		if (NCR5380_poll_politely2(hostdata, hostdata->c400_ctl_status,
+		                           CSR_HOST_BUF_NOT_RDY, 0,
+		                           hostdata->c400_ctl_status,
+		                           CSR_GATED_53C80_IRQ,
+		                           CSR_GATED_53C80_IRQ, HZ / 64) < 0 ||
+		    NCR5380_read(hostdata->c400_ctl_status) & CSR_HOST_BUF_NOT_RDY) {
+			/* Both 128 B buffers are in use */
+			if (start >= 128)
+				start -= 128;
+			if (start >= 128)
+				start -= 128;
+			break;
+		}
 
-		if (NCR5380_read(hostdata->c400_blk_cnt) == 0)
+		if (start >= len && NCR5380_read(hostdata->c400_blk_cnt) == 0)
 			break;
-		while (NCR5380_read(hostdata->c400_ctl_status) & CSR_HOST_BUF_NOT_RDY)
-			; // FIXME - timeout
 
-		if (hostdata->io_port && hostdata->io_width == 2)
-			outsw(hostdata->io_port + hostdata->c400_host_buf,
-							src + start, 64);
-		else if (hostdata->io_port)
-			outsb(hostdata->io_port + hostdata->c400_host_buf,
-							src + start, 128);
-		else
-			memcpy_toio(hostdata->io + NCR53C400_host_buffer,
-			            src + start, 128);
+		if (NCR5380_read(hostdata->c400_ctl_status) & CSR_GATED_53C80_IRQ) {
+			/* Host buffer is empty, other one is in use */
+			if (start >= 128)
+				start -= 128;
+			break;
+		}
 
-		start += 128;
-		blocks--;
-	}
-	if (blocks) {
-		while (NCR5380_read(hostdata->c400_ctl_status) & CSR_HOST_BUF_NOT_RDY)
-			; // FIXME - no timeout
+		if (start >= len)
+			continue;
 
 		if (hostdata->io_port && hostdata->io_width == 2)
 			outsw(hostdata->io_port + hostdata->c400_host_buf,
@@ -608,28 +624,33 @@ static inline int generic_NCR5380_psend(struct NCR5380_hostdata *hostdata,
 		else
 			memcpy_toio(hostdata->io + NCR53C400_host_buffer,
 			            src + start, 128);
-
 		start += 128;
-		blocks--;
-	}
+	} while (1);
 
-out_wait:
-	hostdata->pdma_residual = len - start;
+	residual = len - start;
 
-	/* wait for 53C80 registers to be available */
-	while (!(NCR5380_read(hostdata->c400_ctl_status) & CSR_53C80_REG)) {
-		udelay(4); /* DTC436 chip hangs without this */
-		/* FIXME - no timeout */
+	if (residual != 0) {
+		/* 53c80 interrupt or transfer timeout. Reset 53c400 logic. */
+		NCR5380_write(hostdata->c400_ctl_status, CSR_RESET);
+		NCR5380_write(hostdata->c400_ctl_status, CSR_BASE);
+	}
+	wait_for_53c80_access(hostdata);
+
+	if (residual == 0) {
+		if (NCR5380_poll_politely(hostdata, TARGET_COMMAND_REG,
+		                          TCR_LAST_BYTE_SENT, TCR_LAST_BYTE_SENT,
+		                          HZ / 64) < 0)
+			scmd_printk(KERN_ERR, hostdata->connected,
+			            "%s: Last Byte Sent timeout\n", __func__);
+
+		if (NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG,
+		                          BASR_END_DMA_TRANSFER, BASR_END_DMA_TRANSFER,
+		                          HZ / 64) < 0)
+			scmd_printk(KERN_ERR, hostdata->connected, "%s: End of DMA timeout\n",
+			            __func__);
 	}
 
-	while (!(NCR5380_read(TARGET_COMMAND_REG) & TCR_LAST_BYTE_SENT))
-		; 	// TIMEOUT
-
-	if (NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG,
-	                          BASR_END_DMA_TRANSFER, BASR_END_DMA_TRANSFER,
-	                          HZ / 64) < 0)
-		scmd_printk(KERN_ERR, hostdata->connected, "%s: End of DMA timeout (%d)\n",
-		            __func__, hostdata->pdma_residual);
+	hostdata->pdma_residual = residual;
 
 	return 0;
 }
-- 
2.13.0

[PATCH v7 3/6] g_NCR5380: Cleanup comments and whitespace

[Finn Thain]

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
---
 drivers/scsi/g_NCR5380.c | 61 ++++++++++++++++++++++--------------------------
 1 file changed, 28 insertions(+), 33 deletions(-)

diff --git a/drivers/scsi/g_NCR5380.c b/drivers/scsi/g_NCR5380.c
index 911a4300ea51..dedaed2d16e4 100644
--- a/drivers/scsi/g_NCR5380.c
+++ b/drivers/scsi/g_NCR5380.c
@@ -1,17 +1,17 @@
 /*
  * Generic Generic NCR5380 driver
- *	
+ *
  * Copyright 1993, Drew Eckhardt
- *	Visionary Computing
- *	(Unix and Linux consulting and custom programming)
- *	drew@colorado.edu
- *      +1 (303) 440-4894
+ * Visionary Computing
+ * (Unix and Linux consulting and custom programming)
+ * drew@colorado.edu
+ * +1 (303) 440-4894
  *
  * NCR53C400 extensions (c) 1994,1995,1996, Kevin Lentin
- *    K.Lentin@cs.monash.edu.au
+ * K.Lentin@cs.monash.edu.au
  *
  * NCR53C400A extensions (c) 1996, Ingmar Baumgart
- *    ingmar@gonzo.schwaben.de
+ * ingmar@gonzo.schwaben.de
  *
  * DTC3181E extensions (c) 1997, Ronald van Cuijlenborg
  * ronald.van.cuijlenborg@tip.nl or nutty@dds.nl
@@ -481,15 +481,14 @@ static void generic_NCR5380_release_resources(struct Scsi_Host *instance)
 }
 
 /**
- *	generic_NCR5380_pread - pseudo DMA read
- *	@hostdata: scsi host private data
- *	@dst: buffer to read into
- *	@len: buffer length
+ * generic_NCR5380_pread - pseudo DMA read
+ * @hostdata: scsi host private data
+ * @dst: buffer to write into
+ * @len: transfer size
  *
- *	Perform a pseudo DMA mode read from an NCR53C400 or equivalent
- *	controller
+ * Perform a pseudo DMA mode receive from a 53C400 or equivalent device.
  */
- 
+
 static inline int generic_NCR5380_pread(struct NCR5380_hostdata *hostdata,
                                         unsigned char *dst, int len)
 {
@@ -508,10 +507,10 @@ static inline int generic_NCR5380_pread(struct NCR5380_hostdata *hostdata,
 
 		if (hostdata->io_port && hostdata->io_width == 2)
 			insw(hostdata->io_port + hostdata->c400_host_buf,
-							dst + start, 64);
+			     dst + start, 64);
 		else if (hostdata->io_port)
 			insb(hostdata->io_port + hostdata->c400_host_buf,
-							dst + start, 128);
+			     dst + start, 128);
 		else
 			memcpy_fromio(dst + start,
 				hostdata->io + NCR53C400_host_buffer, 128);
@@ -558,13 +557,12 @@ static inline int generic_NCR5380_pread(struct NCR5380_hostdata *hostdata,
 }
 
 /**
- *	generic_NCR5380_pwrite - pseudo DMA write
- *	@hostdata: scsi host private data
- *	@dst: buffer to read into
- *	@len: buffer length
+ * generic_NCR5380_pwrite - pseudo DMA write
+ * @hostdata: scsi host private data
+ * @src: buffer to read from
+ * @len: transfer size
  *
- *	Perform a pseudo DMA mode read from an NCR53C400 or equivalent
- *	controller
+ * Perform a pseudo DMA mode send to a 53C400 or equivalent device.
  */
 
 static inline int generic_NCR5380_pwrite(struct NCR5380_hostdata *hostdata,
@@ -603,10 +601,10 @@ static inline int generic_NCR5380_pwrite(struct NCR5380_hostdata *hostdata,
 
 		if (hostdata->io_port && hostdata->io_width == 2)
 			outsw(hostdata->io_port + hostdata->c400_host_buf,
-							src + start, 64);
+			      src + start, 64);
 		else if (hostdata->io_port)
 			outsb(hostdata->io_port + hostdata->c400_host_buf,
-							src + start, 128);
+			      src + start, 128);
 		else
 			memcpy_toio(hostdata->io + NCR53C400_host_buffer,
 			            src + start, 128);
@@ -656,10 +654,8 @@ static int generic_NCR5380_dma_residual(struct NCR5380_hostdata *hostdata)
 	return hostdata->pdma_residual;
 }
 
-/*
- *	Include the NCR5380 core code that we build our driver around	
- */
- 
+/* Include the core driver code. */
+
 #include "NCR5380.c"
 
 static struct scsi_host_template driver_template = {
@@ -679,11 +675,10 @@ static struct scsi_host_template driver_template = {
 	.max_sectors		= 128,
 };
 
-
 static int generic_NCR5380_isa_match(struct device *pdev, unsigned int ndev)
 {
 	int ret = generic_NCR5380_init_one(&driver_template, pdev, base[ndev],
-					  irq[ndev], card[ndev]);
+	                                   irq[ndev], card[ndev]);
 	if (ret) {
 		if (base[ndev])
 			printk(KERN_WARNING "Card not found at address 0x%03x\n",
@@ -695,7 +690,7 @@ static int generic_NCR5380_isa_match(struct device *pdev, unsigned int ndev)
 }
 
 static int generic_NCR5380_isa_remove(struct device *pdev,
-				   unsigned int ndev)
+                                      unsigned int ndev)
 {
 	generic_NCR5380_release_resources(dev_get_drvdata(pdev));
 	dev_set_drvdata(pdev, NULL);
@@ -718,7 +713,7 @@ static struct pnp_device_id generic_NCR5380_pnp_ids[] = {
 MODULE_DEVICE_TABLE(pnp, generic_NCR5380_pnp_ids);
 
 static int generic_NCR5380_pnp_probe(struct pnp_dev *pdev,
-			       const struct pnp_device_id *id)
+                                     const struct pnp_device_id *id)
 {
 	int base, irq;
 
@@ -729,7 +724,7 @@ static int generic_NCR5380_pnp_probe(struct pnp_dev *pdev,
 	irq = pnp_irq(pdev, 0);
 
 	return generic_NCR5380_init_one(&driver_template, &pdev->dev, base, irq,
-				       id->driver_data);
+	                                id->driver_data);
 }
 
 static void generic_NCR5380_pnp_remove(struct pnp_dev *pdev)
-- 
2.13.0

Re: [PATCH v7 0/6] g_NCR5380: PDMA fixes and cleanup

[Ondrej Zary]

On Monday 03 July 2017 09:59:05 Finn Thain wrote:
> Ondrej, would you please test this new series?
>
> Changed since v1:
> - PDMA transfer residual is calculated earlier.
> - End of DMA flag check is now polled (if there is any residual).
>
> Changed since v2:
> - Bail out of transfer loops when Gated IRQ gets asserted.
> - Make udelay conditional on board type.
> - Drop sg_tablesize patch due to performance regression.
>
> Changed since v3:
> - Add Ondrej's workaround for corrupt WRITE commands on DTC boards.
> - Reset the 53c400 logic after any short PDMA transfer.
> - Don't fail the transfer if the 53c400 logic got a reset.
>
> Changed since v4:
> - Bail out of transfer loops when Gated IRQ gets asserted. (Again.)
> - Always call wait_for_53c80_registers() at end of transfer.
> - Drain chip buffers after PDMA receive is interrupted.
> - Rework residual calculation.
> - Add new patch to correct DMA terminology.
>
> Changed since v5:
> - Rework residual calculation to account for on-chip buffer swap.
> - Attempt to retain the disconnect/IRQ detection in the DTC436 workaround.
> - Move all DTC436 workarounds to final patch.
>
> Changed since v6:
> - Fix residual calculation for the buffer timeout case.
> - Iterate after sending final 128 bytes to check for buffer timeout.
> - Don't log the residual value when it is known to be zero.
>
>
> Finn Thain (2):
>   g_NCR5380: Cleanup comments and whitespace
>   g_NCR5380: Use unambiguous terminology for PDMA send and receive
>
> Ondrej Zary (4):
>   g_NCR5380: Fix PDMA transfer size
>   g_NCR5380: End PDMA transfer correctly on target disconnection
>   g_NCR5380: Re-work PDMA loops
>   g_NCR5380: Two DTC436 PDMA workarounds
>
>  drivers/scsi/g_NCR5380.c | 277
> ++++++++++++++++++++++++++--------------------- 1 file changed, 155
> insertions(+), 122 deletions(-)

Everything works fine! No corruption, no hangs, rescan-scsi-bus works.

Tested cards:
Canon FG2-5202 (53C400 chip, MMIO)
DTC-3181L (DTCT-436P chip, PIO)
HP C2502 (53C400A chip, PIO)

Tested devices:
QUANTUM  LP240S GM240S01X 4.6
IBM      DORS-32160       WA0A
SONY     CD-ROM CDU-415   1.1g
SONY     CD-ROM CDU-55S   1.0t

Tested-by: Ondrej Zary <linux@rainbow-software.org>

-- 
Ondrej Zary

Re: [PATCH v7 0/6] g_NCR5380: PDMA fixes and cleanup

[Finn Thain]

On Tue, 4 Jul 2017, Ondrej Zary wrote:

> 
> Everything works fine! No corruption, no hangs, rescan-scsi-bus works.
> 
> Tested cards:
> Canon FG2-5202 (53C400 chip, MMIO)
> DTC-3181L (DTCT-436P chip, PIO)
> HP C2502 (53C400A chip, PIO)
> 
> Tested devices:
> QUANTUM  LP240S GM240S01X 4.6
> IBM      DORS-32160       WA0A
> SONY     CD-ROM CDU-415   1.1g
> SONY     CD-ROM CDU-55S   1.0t
> 
> Tested-by: Ondrej Zary <linux@rainbow-software.org>
> 

Great! Thanks for testing all of those revisions.

-- 

Re: [PATCH v7 0/6] g_NCR5380: PDMA fixes and cleanup

[Martin K. Petersen]

Finn,

> Ondrej, would you please test this new series?

Applied to 4.14/scsi-queue. Thank you!

-- 
Martin K. Petersen	Oracle Linux Engineering