This is a note to let you know that I've just added the patch titled
scsi: NCR5380: Check for phase match during PDMA fixup
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
scsi-ncr5380-check-for-phase-match-during-pdma-fixup.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 254a58d768b19353159bed06fea5998afa7ba254
Author: Finn Thain <fthain@xxxxxxxxxxxxxx>
Date: Wed Aug 7 13:36:28 2024 +1000
scsi: NCR5380: Check for phase match during PDMA fixup
[ Upstream commit 5768718da9417331803fc4bc090544c2a93b88dc ]
It's not an error for a target to change the bus phase during a transfer.
Unfortunately, the FLAG_DMA_FIXUP workaround does not allow for that -- a
phase change produces a DRQ timeout error and the device borken flag will
be set.
Check the phase match bit during FLAG_DMA_FIXUP processing. Don't forget to
decrement the command residual. While we are here, change shost_printk()
into scmd_printk() for better consistency with other DMA error messages.
Tested-by: Stan Johnson <userm57@xxxxxxxxx>
Fixes: 55181be8ced1 ("ncr5380: Replace redundant flags with FLAG_NO_DMA_FIXUP")
Signed-off-by: Finn Thain <fthain@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/99dc7d1f4c825621b5b120963a69f6cd3e9ca659.1723001788.git.fthain@xxxxxxxxxxxxxx
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c
index cea3a79d538e4..00e245173320c 100644
--- a/drivers/scsi/NCR5380.c
+++ b/drivers/scsi/NCR5380.c
@@ -1485,6 +1485,7 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance,
unsigned char **data)
{
struct NCR5380_hostdata *hostdata = shost_priv(instance);
+ struct NCR5380_cmd *ncmd = NCR5380_to_ncmd(hostdata->connected);
int c = *count;
unsigned char p = *phase;
unsigned char *d = *data;
@@ -1496,7 +1497,7 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance,
return -1;
}
- NCR5380_to_ncmd(hostdata->connected)->phase = p;
+ ncmd->phase = p;
if (p & SR_IO) {
if (hostdata->read_overruns)
@@ -1608,45 +1609,44 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance,
* request.
*/
- if (hostdata->flags & FLAG_DMA_FIXUP) {
- if (p & SR_IO) {
- /*
- * The workaround was to transfer fewer bytes than we
- * intended to with the pseudo-DMA read function, wait for
- * the chip to latch the last byte, read it, and then disable
- * pseudo-DMA mode.
- *
- * After REQ is asserted, the NCR5380 asserts DRQ and ACK.
- * REQ is deasserted when ACK is asserted, and not reasserted
- * until ACK goes false. Since the NCR5380 won't lower ACK
- * until DACK is asserted, which won't happen unless we twiddle
- * the DMA port or we take the NCR5380 out of DMA mode, we
- * can guarantee that we won't handshake another extra
- * byte.
- */
-
- if (NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG,
- BASR_DRQ, BASR_DRQ, 0) < 0) {
- result = -1;
- shost_printk(KERN_ERR, instance, "PDMA read: DRQ timeout\n");
- }
- if (NCR5380_poll_politely(hostdata, STATUS_REG,
- SR_REQ, 0, 0) < 0) {
- result = -1;
- shost_printk(KERN_ERR, instance, "PDMA read: !REQ timeout\n");
- }
- d[*count - 1] = NCR5380_read(INPUT_DATA_REG);
- } else {
- /*
- * Wait for the last byte to be sent. If REQ is being asserted for
- * the byte we're interested, we'll ACK it and it will go false.
- */
- if (NCR5380_poll_politely2(hostdata,
- BUS_AND_STATUS_REG, BASR_DRQ, BASR_DRQ,
- BUS_AND_STATUS_REG, BASR_PHASE_MATCH, 0, 0) < 0) {
- result = -1;
- shost_printk(KERN_ERR, instance, "PDMA write: DRQ and phase timeout\n");
+ if ((hostdata->flags & FLAG_DMA_FIXUP) &&
+ (NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH)) {
+ /*
+ * The workaround was to transfer fewer bytes than we
+ * intended to with the pseudo-DMA receive function, wait for
+ * the chip to latch the last byte, read it, and then disable
+ * DMA mode.
+ *
+ * After REQ is asserted, the NCR5380 asserts DRQ and ACK.
+ * REQ is deasserted when ACK is asserted, and not reasserted
+ * until ACK goes false. Since the NCR5380 won't lower ACK
+ * until DACK is asserted, which won't happen unless we twiddle
+ * the DMA port or we take the NCR5380 out of DMA mode, we
+ * can guarantee that we won't handshake another extra
+ * byte.
+ *
+ * If sending, wait for the last byte to be sent. If REQ is
+ * being asserted for the byte we're interested, we'll ACK it
+ * and it will go false.
+ */
+ if (!NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG,
+ BASR_DRQ, BASR_DRQ, 0)) {
+ if ((p & SR_IO) &&
+ (NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH)) {
+ if (!NCR5380_poll_politely(hostdata, STATUS_REG,
+ SR_REQ, 0, 0)) {
+ d[c] = NCR5380_read(INPUT_DATA_REG);
+ --ncmd->this_residual;
+ } else {
+ result = -1;
+ scmd_printk(KERN_ERR, hostdata->connected,
+ "PDMA fixup: !REQ timeout\n");
+ }
}
+ } else if (NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH) {
+ result = -1;
+ scmd_printk(KERN_ERR, hostdata->connected,
+ "PDMA fixup: DRQ timeout\n");
}
}
