+/*
+ * ata_scsi_map_proto - Map pass-thru protocol value to taskfile value.
+ * @byte1: Byte 1 from pass-thru CDB.
+ *
+ * RETURNS:
+ * ATA_PROT_UNKNOWN if mapping failed/unimplemented, protocol otherwise.
+ */
+static u8
+ata_scsi_map_proto(u8 byte1)
+{
+ switch((byte1 & 0x1e) >> 1) {
+ case 3: /* Non-data */
+ return ATA_PROT_NODATA;
+
+ case 6: /* DMA */
+ return ATA_PROT_DMA;
+
+ case 4: /* PIO Data-in */
+ case 5: /* PIO Data-out */
+ return ATA_PROT_PIO;
+
+ case 10: /* Device Reset */
+ case 0: /* Hard Reset */
+ case 1: /* SRST */
+ case 2: /* Bus Idle */
+ case 7: /* Packet */
+ case 8: /* DMA Queued */
+ case 9: /* Device Diagnostic */
+ case 11: /* UDMA Data-in */
+ case 12: /* UDMA Data-Out */
+ case 13: /* FPDMA */
+ default: /* Reserved */
+ break;
+ }
+
+ return ATA_PROT_UNKNOWN;
+}
+
+/**
+ * ata_scsi_pass_thru - convert ATA pass-thru CDB to taskfile
+ * @qc: command structure to be initialized
+ * @scsicmd: SCSI command to convert
+ *
+ * Handles either 12 or 16-byte versions of the CDB.
+ *
+ * RETURNS:
+ * Zero on success, non-zero on failure.
+ */
+static unsigned int
+ata_scsi_pass_thru(struct ata_queued_cmd *qc, const u8 *scsicmd)
+{
+ struct ata_taskfile *tf = &(qc->tf);
+ struct scsi_cmnd *cmd = qc->scsicmd;
+
+ if ((tf->protocol = ata_scsi_map_proto(scsicmd[1])) == ATA_PROT_UNKNOWN)
+ goto invalid_fld;
+
+ if (scsicmd[1] & 0xe0)
+ /* PIO multi not supported yet */
+ goto invalid_fld;
+
+ /*
+ * 12 and 16 byte CDBs use different offsets to
+ * provide the various register values.
+ */
+ if (scsicmd[0] == ATA_16) {
+ /*
+ * 16-byte CDB - may contain extended commands.
+ *
+ * If that is the case, copy the upper byte register values.
+ */
+ if (scsicmd[1] & 0x01) {
+ tf->hob_feature = scsicmd[3];
+ tf->hob_nsect = scsicmd[5];
+ tf->hob_lbal = scsicmd[7];
+ tf->hob_lbam = scsicmd[9];
+ tf->hob_lbah = scsicmd[11];
+ tf->flags |= ATA_TFLAG_LBA48;
+ } else
+ tf->flags &= ~ATA_TFLAG_LBA48;
+
+ /*
+ * Always copy low byte, device and command registers.
+ */
+ tf->feature = scsicmd[4];
+ tf->nsect = scsicmd[6];
+ tf->lbal = scsicmd[8];
+ tf->lbam = scsicmd[10];
+ tf->lbah = scsicmd[12];
+ tf->device = scsicmd[13];
+ tf->command = scsicmd[14];
+ } else {
+ /*
+ * 12-byte CDB - incapable of extended commands.
+ */
+ tf->flags &= ~ATA_TFLAG_LBA48;
+
+ tf->feature = scsicmd[3];
+ tf->nsect = scsicmd[4];
+ tf->lbal = scsicmd[5];
+ tf->lbam = scsicmd[6];
+ tf->lbah = scsicmd[7];
+ tf->device = scsicmd[8];
+ tf->command = scsicmd[9];
+ }
+ /*
+ * If slave is possible, enforce correct master/slave bit
+ */
+ if (qc->ap->flags & ATA_FLAG_SLAVE_POSS)
+ tf->device = qc->dev->devno ?
+ tf->device | ATA_DEV1 : tf->device & ~ATA_DEV1;
+
+ /*
+ * Filter SET_FEATURES - XFER MODE command -- otherwise,
+ * SET_FEATURES - XFER MODE must be preceded/succeeded
+ * by an update to hardware-specific registers for each
+ * controller (i.e. the reason for ->set_piomode(),
+ * ->set_dmamode(), and ->post_set_mode() hooks).
+ */
+ if ((tf->command == ATA_CMD_SET_FEATURES)
+ && (tf->feature == SETFEATURES_XFER))
+ goto invalid_fld;
+
+ /*
+ * Set flags so that all registers will be written,
+ * and pass on write indication (used for PIO/DMA
+ * setup.)
+ */
+ tf->flags |= (ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE);
+
+ if (cmd->sc_data_direction == DMA_TO_DEVICE)
+ tf->flags |= ATA_TFLAG_WRITE;
+
+ /*
+ * Set transfer length.
+ *
+ * TODO: find out if we need to do more here to
+ * cover scatter/gather case.
+ */
+ qc->nsect = cmd->bufflen / ATA_SECT_SIZE;
+
+ return 0;
+
+ invalid_fld:
+ ata_scsi_set_sense(qc->scsicmd, ILLEGAL_REQUEST, 0x24, 0x00);
+ /* "Invalid field in cdb" */
+ return 1;
+}
+