diff --git a/drivers/scsi/sata_sil24.c b/drivers/scsi/sata_sil24.c
index 55e744d..73803a5 100644
--- a/drivers/scsi/sata_sil24.c
+++ b/drivers/scsi/sata_sil24.c
@@ -139,6 +139,7 @@ enum {
 	PORT_CS_DEV_RST		= (1 << 1), /* device reset */
 	PORT_CS_INIT		= (1 << 2), /* port initialize */
 	PORT_CS_IRQ_WOC		= (1 << 3), /* interrupt write one to clear */
+	PORT_CS_CDB16		= (1 << 5), /* 0=12b cdb, 1=16b cdb */
 	PORT_CS_RESUME		= (1 << 6), /* port resume */
 	PORT_CS_32BIT_ACTV	= (1 << 10), /* 32-bit activation */
 	PORT_CS_PM_EN		= (1 << 13), /* port multiplier enable */
@@ -188,11 +189,36 @@ enum {
 	PORT_CERR_XFR_PCIPERR	= 35, /* PSD ecode 11 - PCI prity err during transfer */
 	PORT_CERR_SENDSERVICE	= 36, /* FIS received while sending service */
 
+	/* bits of PRB control field */
+	CTRL_PROTOCOL		= (1 << 0),  /* override def. ATA protocol */
+	CTRL_PACKET_READ	= (1 << 4),  /* PACKET cmd read */
+	CTRL_PACKET_WRITE	= (1 << 5),  /* PACKET cmd write */
+	CTRL_NIEN		= (1 << 6),  /* Mask completion irq */
+	CTRL_SRST		= (1 << 7),  /* Soft reset request (ign BSY?) */
+
+	/* PRB protocol field */
+	PRB_PROT_PACKET		= (1 << 16),
+	PRB_PROT_TCQ		= (1 << 17),
+	PRB_PROT_NCQ		= (1 << 18),
+	PRB_PROT_READ		= (1 << 19),
+	PRB_PROT_WRITE		= (1 << 20),
+	PRB_PROT_TRANSPARENT	= (1 << 21),
+
+	/* port RAM layout (0x000 - 0xFFF) */
+	RAM_SLOT_SZ		= 0x80,		/* size of one slot */
+	RAM_SLOT_N		= 31,
+	RAM_SLOT_PM_OFS		= 0xf80,
+	RAM_SLOT_PM_SZ		= 8,		/* struct sil24_pm_reg */
+	RAM_SLOT_PM_N		= 16,
+
 	/*
 	 * Other constants
 	 */
 	SGE_TRM			= (1 << 31), /* Last SGE in chain */
-	PRB_SOFT_RST		= (1 << 7),  /* Soft reset request (ign BSY?) */
+	SGE_LNK			= (1 << 30), /* linked list;
+						Points to SGT, not SGE */
+	SGE_DRD			= (1 << 29), /* discard data read (/dev/null) */
+					     /* data address ignored */
 
 	/* board id */
 	BID_SIL3124		= 0,
@@ -207,6 +233,19 @@ struct sil24_cmd_block {
 	struct sil24_sge sge[LIBATA_MAX_PRD];
 };
 
+/* ATAPI PRB */
+struct sil24_atapi_block {
+	struct sil24_prb prb;
+	u8 cdb[16];
+	struct sil24_sge sge[1];
+};
+
+/* per-port multiplier set of registers */
+struct sil24_pm_reg {
+	u32		status;
+	u32		qactive;
+};
+
 /*
  * ap->private_data
  *