diff --git a/arch/powerpc/boot/dts/mpc5121ads.dts
b/arch/powerpc/boot/dts/mpc5121ads.dts
index d2b2db7..bdaf534 100644
--- a/arch/powerpc/boot/dts/mpc5121ads.dts
+++ b/arch/powerpc/boot/dts/mpc5121ads.dts
@@ -325,6 +325,7 @@
 			interrupt-parent = < &ipic >;
 		};
 
+		// UART port numbers are enumerated in the order they
occur
 		// 512x PSCs are not 52xx PSC compatible
 		// PSC3 serial port A aka ttyPSC0
 		serial@11300 {
@@ -332,7 +333,6 @@
 			compatible = "fsl,mpc5121-psc-uart",
"fsl,mpc5121-psc";
 			// Logical port assignment needed until driver
 			// learns to use aliases
-			port-number = <0>;
 			cell-index = <3>;
 			reg = <0x11300 0x100>;
 			interrupts = <40 0x8>;
@@ -347,7 +347,6 @@
 			compatible = "fsl,mpc5121-psc-uart",
"fsl,mpc5121-psc";
 			// Logical port assignment needed until driver
 			// learns to use aliases
-			port-number = <1>;
 			cell-index = <4>;
 			reg = <0x11400 0x100>;
 			interrupts = <40 0x8>;
diff --git a/arch/powerpc/platforms/512x/clock.c
b/arch/powerpc/platforms/512x/clock.c
index 8733143..d32c83f 100644
--- a/arch/powerpc/platforms/512x/clock.c
+++ b/arch/powerpc/platforms/512x/clock.c
@@ -681,7 +681,7 @@ static void psc_clks_init(void)
 				psc_calc_rate(clk, pscnum, np);
 			sprintf(clk->name, "psc%d_mclk", pscnum);
 			clk_register(clk);
-			clk_enable(clk);
+			mpc5121_clk_enable(clk);
 		}
 	}
 }
diff --git a/arch/powerpc/platforms/512x/mpc5121_ads.c
b/arch/powerpc/platforms/512x/mpc5121_ads.c
index aa4d5a8..44a0a51 100644
--- a/arch/powerpc/platforms/512x/mpc5121_ads.c
+++ b/arch/powerpc/platforms/512x/mpc5121_ads.c
@@ -64,6 +64,7 @@ static int __init mpc5121_ads_probe(void)
 void __init mpc5121_ads_init_early(void)
 {
 	mpc512x_init_diu();
+	mpc5121_psc_early_init();
 }
 
 define_machine(mpc5121_ads) {
diff --git a/arch/powerpc/platforms/512x/mpc512x.h
b/arch/powerpc/platforms/512x/mpc512x.h
index 1cfe9d5..fb69e3f 100644
--- a/arch/powerpc/platforms/512x/mpc512x.h
+++ b/arch/powerpc/platforms/512x/mpc512x.h
@@ -21,3 +21,4 @@ extern void __init mpc512x_init_diu(void);
 extern void __init mpc512x_setup_diu(void);
 extern struct fsl_diu_shared_fb diu_shared_fb;
 #endif				/* __MPC512X_H__ */
+extern void __init mpc5121_psc_early_init(void);
diff --git a/arch/powerpc/platforms/512x/mpc512x_shared.c
b/arch/powerpc/platforms/512x/mpc512x_shared.c
index 65b0a5d..1d74046 100644
--- a/arch/powerpc/platforms/512x/mpc512x_shared.c
+++ b/arch/powerpc/platforms/512x/mpc512x_shared.c
@@ -61,6 +61,86 @@ void mpc512x_restart(char *cmd)
 		;
 }
 
+#define DEFAULT_FIFO_SIZE 16
+
+static unsigned int get_fifo_size(struct device_node *np, int psc_num,
char *fifo_name)
+{
+	const unsigned int *fp;
+
+	fp = of_get_property(np, fifo_name, NULL);
+	if (fp) {
+		/* make sure has at least 1 byte */
+		return *fp ? *fp : 1;
+	}
+
+	printk(KERN_WARNING "no %s property for psc%d defaulting to
%d\n",
+		fifo_name, psc_num, DEFAULT_FIFO_SIZE);
+	return DEFAULT_FIFO_SIZE;
+}
+
+static void __init mpc5121_psc_lowlevel_clock_init(void)
+{
+	struct device_node *np;
+	const u32 *cell_index;
+	void __iomem *clockctl;
+
+	np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121-clock");
+	clockctl = of_iomap(np, 0);
+	of_node_put(np);
+
+	if (clockctl) {
+		for_each_compatible_node(np, NULL,
"fsl,mpc5121-psc-uart") {
+			cell_index = of_get_property(np, "cell-index",
NULL);
+			if (cell_index) {
+				setbits32(clockctl+4, 0x08000000 >>
*cell_index);
+			}
+		}
+	}
+	iounmap(clockctl);
+}
+
+static void __init mpc5121_psc_fifo_init(void)
+{
+	struct device_node *np;
+	const u32 *cell_index;
+	int fifobase = 0; /* current fifo address in 32 bit words */
+
+	for_each_compatible_node(np, NULL, "fsl,mpc5121-psc") {
+		cell_index = of_get_property(np, "cell-index", NULL);
+		if (cell_index) {
+			int psc_num = *cell_index;
+			unsigned int tx_fifo_size;
+			unsigned int rx_fifo_size;
+			void __iomem *psc;
+
+			tx_fifo_size = get_fifo_size(np, psc_num,
"tx-fifo-size");
+			rx_fifo_size = get_fifo_size(np, psc_num,
"rx-fifo-size");
+
+			/* size in register is in 4 byte words */
+			tx_fifo_size = (tx_fifo_size + 3)/4;
+			rx_fifo_size = (rx_fifo_size + 3)/4;
+
+			psc = of_iomap(np, 0);
+
+			/* tx fifo size register is at 0x9c and rx at
0xdc */
+			out_be32(psc + 0x9c, (fifobase << 16) |
tx_fifo_size);
+			fifobase += tx_fifo_size;
+			out_be32(psc + 0xdc, (fifobase << 16) |
rx_fifo_size);
+			fifobase += rx_fifo_size;
+
+			iounmap(psc);
+		}
+	}
+}
+
+/* Early PSC initialization that may be
+ * needed before console_init is called */
+void __init mpc5121_psc_early_init(void)
+{
+	mpc5121_psc_lowlevel_clock_init();
+	mpc5121_psc_fifo_init();
+}
+
 
 struct fsl_diu_shared_fb {
 	char		gamma[0x300];	/* 32-bit aligned! */
diff --git a/drivers/serial/mpc52xx_uart.c
b/drivers/serial/mpc52xx_uart.c
index 7ce9e9f..d0b1d8f 100644
--- a/drivers/serial/mpc52xx_uart.c
+++ b/drivers/serial/mpc52xx_uart.c
@@ -154,9 +154,6 @@ static void mpc52xx_psc_fifo_init(struct uart_port
*port)
 	struct mpc52xx_psc __iomem *psc = PSC(port);
 	struct mpc52xx_psc_fifo __iomem *fifo = FIFO_52xx(port);
 
-	/* /32 prescaler */
-	out_be16(&psc->mpc52xx_psc_clock_select, 0xdd00);
-
 	out_8(&fifo->rfcntl, 0x00);
 	out_be16(&fifo->rfalarm, 0x1ff);
