[PATCH] target: Handle ATA_PASS_THROUGH_16 passthrough

[mengcong <mc@linux.vnet.ibm.com>]

The cdrecord uses ATA_PASS_THROUGH_16 command while burning CDs
with a SATA CD-ROM. This patch adds support to it so that PSCSI 
CD-ROM passthrough works with the cdrecord.

Signed-off-by: Cong Meng <mc@linux.vnet.ibm.com>
---
 drivers/target/target_core_transport.c |   30 ++++++++++++++++++++++++++++++
 include/scsi/scsi.h                    |    1 +
 2 files changed, 31 insertions(+), 0 deletions(-)

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 2d75c29..41439b3 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -2926,6 +2926,36 @@ static int transport_generic_cmd_sequencer(
 		size = (cdb[7] << 8) | cdb[8];
 		cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
 		break;
+	case ATA_PASS_THROUGH_16:
+		// T_LENGTH
+		switch (cdb[2] & 0x3) {
+		case 0x0:
+			sectors = 0;
+			break;
+		case 0x1:
+			sectors = (((cdb[1] & 0x1) ? cdb[3] : 0) << 8) | cdb[4];
+			break;
+		case 0x2:
+			sectors = (((cdb[1] & 0x1) ? cdb[5] : 0) << 8) | cdb[6];
+			break;
+		case 0x3:
+			pr_err("T_LENGTH=0x3 not supported\n");
+			goto out_invalid_cdb_field;
+			break;
+		}
+		
+		// BYTE_BLOCK
+		if (cdb[2] & 0x4) {
+			// BLOCK
+			// T_TYPE: 512 or sector
+			size = sectors * ((cdb[2] & 0x10) ? 
+				dev->se_sub_dev->se_dev_attrib.block_size : 512);
+		} else {
+			// BYTE
+			size = sectors;
+		}
+		cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
+		break;
 	default:
 		pr_warn("TARGET_CORE[%s]: Unsupported SCSI Opcode"
 			" 0x%02x, sending CHECK_CONDITION.\n",
diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h
index f34a5a8..f6dcd25 100644
--- a/include/scsi/scsi.h
+++ b/include/scsi/scsi.h
@@ -116,6 +116,7 @@ struct scsi_cmnd;
 #define PERSISTENT_RESERVE_IN 0x5e
 #define PERSISTENT_RESERVE_OUT 0x5f
 #define VARIABLE_LENGTH_CMD   0x7f
+#define ATA_PASS_THROUGH_16   0x85
 #define REPORT_LUNS           0xa0
 #define SECURITY_PROTOCOL_IN  0xa2
 #define MAINTENANCE_IN        0xa3
-- 
1.7.7