libata_scsi: Fix ATAPI transfer lengths
Some controller variants snoop the ATAPI length value for Packet
transfers to do state machine and FIFO management. Thus we want to
set it properly, even for cases where it is otherwise meaningless.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index df2e057..ea53e6a 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -2305,8 +2305,8 @@
qc->tf.feature |= ATAPI_PKT_DMA;
} else {
qc->tf.protocol = ATA_PROT_ATAPI;
- qc->tf.lbam = (8 * 1024) & 0xff;
- qc->tf.lbah = (8 * 1024) >> 8;
+ qc->tf.lbam = SCSI_SENSE_BUFFERSIZE;
+ qc->tf.lbah = 0;
}
qc->nbytes = SCSI_SENSE_BUFFERSIZE;
@@ -2415,6 +2415,7 @@
struct ata_device *dev = qc->dev;
int using_pio = (dev->flags & ATA_DFLAG_PIO);
int nodata = (scmd->sc_data_direction == DMA_NONE);
+ unsigned int nbytes;
memset(qc->cdb, 0, dev->cdb_len);
memcpy(qc->cdb, scmd->cmnd, scmd->cmd_len);
@@ -2434,14 +2435,20 @@
if (!using_pio && ata_check_atapi_dma(qc))
using_pio = 1;
+ /* Some controller variants snoop this value for Packet transfers
+ to do state machine and FIFO management. Thus we want to set it
+ properly, and for DMA where it is effectively meaningless */
+ nbytes = min(qc->nbytes, (unsigned int)63 * 1024);
+
+ qc->tf.lbam = (nbytes & 0xFF);
+ qc->tf.lbah = (nbytes >> 8);
+
if (using_pio || nodata) {
/* no data, or PIO data xfer */
if (nodata)
qc->tf.protocol = ATA_PROT_ATAPI_NODATA;
else
qc->tf.protocol = ATA_PROT_ATAPI;
- qc->tf.lbam = (8 * 1024) & 0xff;
- qc->tf.lbah = (8 * 1024) >> 8;
} else {
/* DMA data xfer */
qc->tf.protocol = ATA_PROT_ATAPI_DMA;
@@ -2452,6 +2459,9 @@
qc->tf.feature |= ATAPI_DMADIR;
}
+
+ /* FIXME: We need to translate 0x05 READ_BLOCK_LIMITS to a MODE_SENSE
+ as ATAPI tape drives don't get this right otherwise */
return 0;
}