diff -ruNpd linux-2.6.20.9/drivers/serial/sunzilog.c linux-test/drivers/serial/sunzilog.c
--- linux-2.6.20.9/drivers/serial/sunzilog.c	2007-04-28 15:02:39.000000000 +0100
+++ linux-test/drivers/serial/sunzilog.c	2007-04-28 14:54:49.000000000 +0100
@@ -93,6 +100,8 @@ struct uart_sunzilog_port {
 #define SUNZILOG_FLAG_REGS_HELD		0x00000040
 #define SUNZILOG_FLAG_TX_STOPPED	0x00000080
 #define SUNZILOG_FLAG_TX_ACTIVE		0x00000100
+#define SUNZILOG_FLAG_ESCC		0x00000200
+#define SUNZILOG_FLAG_ISR_HANDLER	0x00000400
 
 	unsigned int cflag;
 
@@ -175,9 +184,11 @@ static void sunzilog_clear_fifo(struct z
 /* This function must only be called when the TX is not busy.  The UART
  * port lock must be held and local interrupts disabled.
  */
-static void __load_zsregs(struct zilog_channel __iomem *channel, unsigned char *regs)
+static int __load_zsregs(struct zilog_channel __iomem *channel, unsigned char *regs)
 {
 	int i;
+	int escc;
+	unsigned char r15;
 
 	/* Let pending transmits finish.  */
 	for (i = 0; i < 1000; i++) {
@@ -230,11 +241,25 @@ static void __load_zsregs(struct zilog_c
 	write_zsreg(channel, R14, regs[R14]);
 
 	/* External status interrupt control.  */
-	write_zsreg(channel, R15, regs[R15]);
+	write_zsreg(channel, R15, (regs[R15] | WR7pEN) & ~FIFOEN);
+
+	/* ESCC Extension Register */
+	r15 = read_zsreg(channel, R15);
+	if (r15 & 0x01)	{
+		write_zsreg(channel, R7,  regs[R7p]);
+
+		/* External status interrupt and FIFO control.  */
+		write_zsreg(channel, R15, regs[R15] & ~WR7pEN);
+		escc = 1;
+	} else {
+		 /* Clear FIFO bit case it is an issue */
+		regs[R15] &= ~FIFOEN;
+		escc = 0;
+	}
 
 	/* Reset external status interrupts.  */
-	write_zsreg(channel, R0, RES_EXT_INT);
-	write_zsreg(channel, R0, RES_EXT_INT);
+	write_zsreg(channel, R0, RES_EXT_INT); /* First Latch  */
+	write_zsreg(channel, R0, RES_EXT_INT); /* Second Latch */
 
 	/* Rewrite R3/R5, this time without enables masked.  */
 	write_zsreg(channel, R3, regs[R3]);
@@ -242,6 +267,8 @@ static void __load_zsregs(struct zilog_c
 
 	/* Rewrite R1, this time without IRQ enabled masked.  */
 	write_zsreg(channel, R1, regs[R1]);
+
+	return escc;
 }
 
 /* Reprogram the Zilog channel HW registers with the copies found in the
@@ -732,7 +759,7 @@ static void sunzilog_enable_ms(struct ua
 		up->curregs[R15] = new_reg;
 
 		/* NOTE: Not subject to 'transmitter active' rule.  */ 
-		write_zsreg(channel, R15, up->curregs[R15]);
+		write_zsreg(channel, R15, up->curregs[R15] & ~WR7pEN);
 	}
 }
 
@@ -862,44 +889,44 @@ sunzilog_convert_to_zs(struct uart_sunzi
 	up->curregs[R14] = BRSRC | BRENAB;
 
 	/* Character size, stop bits, and parity. */
-	up->curregs[3] &= ~RxN_MASK;
-	up->curregs[5] &= ~TxN_MASK;
+	up->curregs[R3] &= ~RxN_MASK;
+	up->curregs[R5] &= ~TxN_MASK;
 	switch (cflag & CSIZE) {
 	case CS5:
-		up->curregs[3] |= Rx5;
-		up->curregs[5] |= Tx5;
+		up->curregs[R3] |= Rx5;
+		up->curregs[R5] |= Tx5;
 		up->parity_mask = 0x1f;
 		break;
 	case CS6:
-		up->curregs[3] |= Rx6;
-		up->curregs[5] |= Tx6;
+		up->curregs[R3] |= Rx6;
+		up->curregs[R5] |= Tx6;
 		up->parity_mask = 0x3f;
 		break;
 	case CS7:
-		up->curregs[3] |= Rx7;
-		up->curregs[5] |= Tx7;
+		up->curregs[R3] |= Rx7;
+		up->curregs[R5] |= Tx7;
 		up->parity_mask = 0x7f;
 		break;
 	case CS8:
 	default:
-		up->curregs[3] |= Rx8;
-		up->curregs[5] |= Tx8;
+		up->curregs[R3] |= Rx8;
+		up->curregs[R5] |= Tx8;
 		up->parity_mask = 0xff;
 		break;
 	};
-	up->curregs[4] &= ~0x0c;
+	up->curregs[R4] &= ~0x0c;
 	if (cflag & CSTOPB)
-		up->curregs[4] |= SB2;
+		up->curregs[R4] |= SB2;
 	else
-		up->curregs[4] |= SB1;
+		up->curregs[R4] |= SB1;
 	if (cflag & PARENB)
-		up->curregs[4] |= PAR_ENAB;
+		up->curregs[R4] |= PAR_ENAB;
 	else
-		up->curregs[4] &= ~PAR_ENAB;
+		up->curregs[R4] &= ~PAR_ENAB;
 	if (!(cflag & PARODD))
-		up->curregs[4] |= PAR_EVEN;
+		up->curregs[R4] |= PAR_EVEN;
 	else
-		up->curregs[4] &= ~PAR_EVEN;
+		up->curregs[R4] &= ~PAR_EVEN;
 
 	up->port.read_status_mask = Rx_OVR;
 	if (iflag & INPCK)
@@ -953,7 +980,9 @@ sunzilog_set_termios(struct uart_port *p
 
 static const char *sunzilog_type(struct uart_port *port)
 {
-	return "zs";
+	struct uart_sunzilog_port *up = UART_ZILOG(port);
+
+	return (up->flags & SUNZILOG_FLAG_ESCC) ? "zs (ESCC)" : "zs";
 }
 
 /* We do not request/release mappings of the registers here, this
@@ -1171,7 +1200,7 @@ static int __init sunzilog_console_setup
 
 	spin_lock_irqsave(&up->port.lock, flags);
 
-	up->curregs[R15] = BRKIE;
+	up->curregs[R15] |= BRKIE;
 	sunzilog_convert_to_zs(up, con->cflag, 0, brg);
 
 	sunzilog_set_mctrl(&up->port, TIOCM_DTR | TIOCM_RTS);
@@ -1230,7 +1259,7 @@ static void __init sunzilog_init_kbdms(s
 		baud = 4800;
 	}
 
-	up->curregs[R15] = BRKIE;
+	up->curregs[R15] |= BRKIE;
 	brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
 	sunzilog_convert_to_zs(up, up->cflag, 0, brg);
 	sunzilog_set_mctrl(&up->port, TIOCM_DTR | TIOCM_RTS);
@@ -1284,8 +1313,18 @@ static void __devinit sunzilog_init_hw(s
 
 	if (up->flags & (SUNZILOG_FLAG_CONS_KEYB |
 			 SUNZILOG_FLAG_CONS_MOUSE)) {
+		up->curregs[R1] = EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
+		up->curregs[R4] = PAR_EVEN | X16CLK | SB1;
+		up->curregs[R3] = RxENAB | Rx8;
+		up->curregs[R5] = TxENAB | Tx8;
+		up->curregs[R6] = 0x00; /* SDLC Address */
+		up->curregs[R7] = 0x7E; /* SDLC Flag    */
+		up->curregs[R9] = NV;
+		up->curregs[R7p] = 0x00;
 		sunzilog_init_kbdms(up, up->port.line);
-		up->curregs[R9] |= (NV | MIE);
+		/* Only enable interrupts if an ISR handler available */
+		if (up->flags & SUNZILOG_FLAG_ISR_HANDLER)
+			up->curregs[R9] |= MIE;
 		write_zsreg(channel, R9, up->curregs[R9]);
 	} else {
 		/* Normal serial TTY. */
@@ -1294,7 +1333,9 @@ static void __devinit sunzilog_init_hw(s
 		up->curregs[R4] = PAR_EVEN | X16CLK | SB1;
 		up->curregs[R3] = RxENAB | Rx8;
 		up->curregs[R5] = TxENAB | Tx8;
-		up->curregs[R9] = NV | MIE;
+		up->curregs[R6] = 0x00; /* SDLC Address */
+		up->curregs[R7] = 0x7E; /* SDLC Flag    */
+		up->curregs[R9] = NV;
 		up->curregs[R10] = NRZ;
 		up->curregs[R11] = TCBR | RCBR;
 		baud = 9600;
@@ -1302,7 +1343,14 @@ static void __devinit sunzilog_init_hw(s
 		up->curregs[R12] = (brg & 0xff);
 		up->curregs[R13] = (brg >> 8) & 0xff;
 		up->curregs[R14] = BRSRC | BRENAB;
-		__load_zsregs(channel, up->curregs);
+		up->curregs[R15] = FIFOEN; /* Use FIFO if on ESCC */
+		up->curregs[R7p] = TxFIFO_LVL | RxFIFO_LVL;
+		if (__load_zsregs(channel, up->curregs)) {
+			up->flags |= SUNZILOG_FLAG_ESCC;
+		}
+		/* Only enable interrupts if an ISR handler available */
+		if (up->flags & SUNZILOG_FLAG_ISR_HANDLER)
+			up->curregs[R9] |= MIE;
 		write_zsreg(channel, R9, up->curregs[R9]);
 	}
 
@@ -1391,12 +1439,14 @@ static int __devinit zs_probe(struct of_
 			return err;
 		}
 	} else {
-		printk(KERN_INFO "%s: Keyboard at MMIO %lx (irq = %d) "
-		       "is a zs\n",
-		       op->dev.bus_id, up[0].port.mapbase, op->irqs[0]);
-		printk(KERN_INFO "%s: Mouse at MMIO %lx (irq = %d) "
-		       "is a zs\n",
-		       op->dev.bus_id, up[1].port.mapbase, op->irqs[0]);
+		printk(KERN_INFO "%s: Keyboard at MMIO 0x%lx (irq = %d) "
+		       "is a %s\n",
+		       op->dev.bus_id, up[0].port.mapbase, op->irqs[0],
+		       sunzilog_type (&up[0].port));
+		printk(KERN_INFO "%s: Mouse at MMIO 0x%lx (irq = %d) "
+		       "is a %s\n",
+		       op->dev.bus_id, up[1].port.mapbase, op->irqs[0],
+		       sunzilog_type (&up[1].port));
 	}
 
 	dev_set_drvdata(&op->dev, &up[0]);
@@ -1488,10 +1538,23 @@ static int __init sunzilog_init(void)
 		goto out_unregister_uart;
 
 	if (zilog_irq != -1) {
+		struct uart_sunzilog_port *up = sunzilog_irq_chain;
 		err = request_irq(zilog_irq, sunzilog_interrupt, IRQF_SHARED,
 				  "zs", sunzilog_irq_chain);
 		if (err)
 			goto out_unregister_driver;
+
+		/* Enable Interrupts */
+		while (up) {
+			struct zilog_channel __iomem *channel;
+
+			/* printk (KERN_INFO "Enable IRQ for ZILOG Hardware %p\n", up); */
+			channel          = ZILOG_CHANNEL_FROM_PORT(&up->port);
+			up->flags       |= SUNZILOG_FLAG_ISR_HANDLER;
+			up->curregs[R9] |= MIE;
+			write_zsreg(channel, R9, up->curregs[R9]);
+			up = up->next;
+		}
 	}
 
 out:
@@ -1516,6 +1579,20 @@ static void __exit sunzilog_exit(void)
 	of_unregister_driver(&zs_driver);
 
 	if (zilog_irq != -1) {
+		struct uart_sunzilog_port *up = sunzilog_irq_chain;
+
+		/* Disable Interrupts */
+		while (up) {
+			struct zilog_channel __iomem *channel;
+
+			/* printk (KERN_INFO "Disable IRQ for ZILOG Hardware %p\n", up); */
+			channel          = ZILOG_CHANNEL_FROM_PORT(&up->port);
+			up->flags       &= ~SUNZILOG_FLAG_ISR_HANDLER;
+			up->curregs[R9] &= ~MIE;
+			write_zsreg(channel, R9, up->curregs[R9]);
+			up = up->next;
+		}
+
 		free_irq(zilog_irq, sunzilog_irq_chain);
 		zilog_irq = -1;
 	}
diff -ruNpd linux-2.6.20.9/drivers/serial/sunzilog.h linux-test/drivers/serial/sunzilog.h
--- linux-2.6.20.9/drivers/serial/sunzilog.h	2004-08-14 11:54:46.000000000 +0100
+++ linux-test/drivers/serial/sunzilog.h	2007-04-28 04:31:04.000000000 +0100
@@ -13,7 +13,8 @@ struct zilog_layout {
 	struct zilog_channel channelA;
 };
 
-#define NUM_ZSREGS    16
+#define	NUM_ZSREGS	17
+#define	R7p		16 /* Written as R7 with P15 bit 0 set */
 
 /* Conversion routines to/from brg time constants from/to bits
  * per second.
@@ -127,6 +128,15 @@ struct zilog_layout {
 
 /* Write Register 7 (Sync bits 8-15/SDLC 01111110) */
 
+/* Write Register 7' (ESCC Only) */
+#define	AUTO_TxFLAG	1	/* Automatic Tx SDLC Flag */
+#define	AUTO_EOM_RST	2	/* Automatic EOM Reset */
+#define	AUTOnRTS	4	/* Automatic /RTS pin deactivation */
+#define	RxFIFO_LVL	8	/* Receive FIFO interrupt level */
+#define	nDTRnREQ	0x10	/* /DTR/REQ timing */
+#define	TxFIFO_LVL	0x20	/* Transmit FIFO interrupt level */
+#define	EXT_RD_EN	0x40	/* Extended read register enable */
+
 /* Write Register 8 (transmit buffer) */
 
 /* Write Register 9 (Master interrupt control) */
@@ -135,6 +145,7 @@ struct zilog_layout {
 #define	DLC	4	/* Disable Lower Chain */
 #define	MIE	8	/* Master Interrupt Enable */
 #define	STATHI	0x10	/* Status high */
+#define	SWIACK  0x20    /* Software Interrupt Ack (not on NMOS) */
 #define	NORESET	0	/* No reset on write to R9 */
 #define	CHRB	0x40	/* Reset channel B */
 #define	CHRA	0x80	/* Reset channel A */
@@ -187,7 +198,9 @@ struct zilog_layout {
 #define	SNRZI	0xe0	/* Set NRZI mode */
 
 /* Write Register 15 (external/status interrupt control) */
+#define	WR7pEN	1	/* WR7' Enable (ESCC only) */
 #define	ZCIE	2	/* Zero count IE */
+#define	FIFOEN	4	/* FIFO Enable (ESCC only) */
 #define	DCDIE	8	/* DCD IE */
 #define	SYNCIE	0x10	/* Sync/hunt IE */
 #define	CTSIE	0x20	/* CTS IE */
@@ -241,6 +254,10 @@ struct zilog_layout {
 #define	CHATxIP	0x10		/* Channel A Tx IP */
 #define	CHARxIP	0x20		/* Channel A Rx IP */
 
+/* Read Register 6 (LSB frame byte count [Not on NMOS]) */
+
+/* Read Register 7 (MSB frame byte count and FIFO status [Not on NMOS]) */
+
 /* Read Register 8 (receive data register) */
 
 /* Read Register 10  (misc status bits) */