6.1-stable review patch. If anyone has any objections, please let me know.
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From: Finn Thain fthain@linux-m68k.org
[ 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@yahoo.com Fixes: 55181be8ced1 ("ncr5380: Replace redundant flags with FLAG_NO_DMA_FIXUP") Signed-off-by: Finn Thain fthain@linux-m68k.org Link: https://lore.kernel.org/r/99dc7d1f4c825621b5b120963a69f6cd3e9ca659.172300178... Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/NCR5380.c | 78 +++++++++++++++++++++--------------------- 1 file changed, 39 insertions(+), 39 deletions(-)
diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c index dece7d9eb4d36..ecd24af4b3f29 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"); } }